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Activities of the NBS Spectrochemical Analysis Section: July 1970 to June 1971 (open access)

Activities of the NBS Spectrochemical Analysis Section: July 1970 to June 1971

Review of the progress in research, instrumentation, and service activities of the Spectrochemical Analysis Section from July 1970 to June 1971.
Date: January 1972
Creator: Heinrich, Kurt F. J. & Rasberry, S. D.
System: The UNT Digital Library
Analysis of Tentative Seismic Design Provisions for Buildings (open access)

Analysis of Tentative Seismic Design Provisions for Buildings

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.
Date: July 1979
Creator: Harris, James Robert; Fenves, Steven J. & Wright, Richard N.
System: The UNT Digital Library
Automated Measurement of Frequency Response of Frequency-Modulated Generators Using the Bessel Null Method (open access)

Automated Measurement of Frequency Response of Frequency-Modulated Generators Using the Bessel Null Method

From abstract: This paper describes a Bessel null technique to measure the frequency response of a frequency-modulated rf carrier and a program to automate frequency response measurements of signal generators with output frequencies from 0.450 to 2000 MHz. The measurements obtained using this technique are more precise than those obtained by a highly trained technician using a manual system.
Date: March 1986
Creator: Major, J. R.; Livingston, E. M. & Adair, Robert T.
System: The UNT Digital Library
Basic Tables for Chemical Analysis (open access)

Basic Tables for Chemical Analysis

Abstract: Tables of important data for use in the analytical chemistry laboratory are provided. These tables contain information for use in gas chromatography, liquid chromatography, infrared and ultraviolet spectrophotometry, mass spectrometry, and wet chemical techniques. Tables relating to safe practice in the analytical laboratory are also included.
Date: April 1986
Creator: Bruno, Thomas J. & Svoronos, Paris D. N.
System: The UNT Digital Library
Beam-Profile Measurement of Laser Pulses Using a Spatial Filter to Sample the Hermite Modes of a String of Pulses (open access)

Beam-Profile Measurement of Laser Pulses Using a Spatial Filter to Sample the Hermite Modes of a String of Pulses

Abstract: As a first step in the development of a beam-profile measuring instrument for laser sources that is capable of determining the distribution of low-order (less than 25) Hermitian modes in a series of laser pulses, I designed and evaluated the three key parts of such an instrument. First, there is the telescope system which allows the incident laser beam to be phase, beamwidth, and beam center matched to the optical spatial filter. Second, there is a brief error analysis of the structure of the mismatch function between the beam out of the telescope and that expected by the filter. Finally, there is the detailed analysis and design of the computer-generated spatial filter that will cause the incident-laser beam to be cross correlated with the low-order Hermite modes and will create an array of light spots in the detector (Fourier transform) plane each of which can be uniquely related to a particular Hermite mode of the original laser pulse. The principal conclusion is that the Hermite mode analysis can be done with better than 99 percent separation between modes, provided the phase between modes is uncorrelated from pulse to pulse when the filter has been fabricated with a two-level, gray-scale …
Date: September 1982
Creator: Johnson, Eric Gunnar, Jr.
System: The UNT Digital Library
Calculation of Sunrise and Sunset Times at Ionospheric Heights Along a Great Circle Path (open access)

Calculation of Sunrise and Sunset Times at Ionospheric Heights Along a Great Circle Path

Formulas, computer program, and illustrations for a great circle path at ionospheric heights.
Date: November 8, 1964
Creator: Brady, A. H. & Crombie, D. D.
System: The UNT Digital Library
The Characteristics of Iris-Fed Millimeterwave Rectangular Microstrip Patch Antennas (open access)

The Characteristics of Iris-Fed Millimeterwave Rectangular Microstrip Patch Antennas

From introduction: The fabrication of various iris-fed millimeterwave rectangular microstrip patch antennas is described. A model is proposed to describe the iris-fed antenna. Irises ranging in size from 15 percent of the area of the patch to the fully open waveguide are used to couple energy into the antenna. Resonance of the antenna is observed to be insensitive to the size of the iris for irises up to 115 percent of the size of the patch. A study is also made of th? relationship of coupling to the antenna as a function of position of the iris with respect to the transverse plane of the waveguide, the iris always being centered with respect to the patch. In general, the antenna has a VSWR in the waveguide feed on the order of 5:1 at resonance, except for the fully open waveguide which gives rise to a VSWR of 2.9:1 at resonance. Far-field antenna power patterns are observed to be quite broad with H-plane beamwidths on the order of 1300. Maximum antenna gain is seen to be 4.5 dBi with 3 dBi typical. An initial study is made of the microstrip patch antenna fed from a longitudinal waveguide wall. Results indicate that …
Date: October 1983
Creator: Greenlee, D. H.; Kanda, Motohisa & Chang, David C.
System: The UNT Digital Library
The Characterization of Optical Fiber Waveguides: A Bibliography with Abstracts, 1970-1980 (open access)

The Characterization of Optical Fiber Waveguides: A Bibliography with Abstracts, 1970-1980

Abstract: This bibliography contains approximately 450 citations of papers concerning the characterization of optical fiber waveguides. Papers from scientific journals, trade journals and conferences are included along with book chapters. The citations of organized by parameter measured and measurement method. Where published abstracts are available they are included.
Date: June 1981
Creator: Day, G. W.
System: The UNT Digital Library
A Coaxial Noise Standard for the 1 GHz to 12.4 GHz Frequency Range (open access)

A Coaxial Noise Standard for the 1 GHz to 12.4 GHz Frequency Range

From introduction: This note describes the design and construction of a coaxial thermal noise standard. The standard is designed to operate at the boiling point of liquid nitrogen with a noise temperature accurate to t 1 K in the frequency range from 1 GHz to 12.4 GHz.
Date: 1984
Creator: Daywitt, William C.
System: The UNT Digital Library
A Comparison of Two Melting-Pressure Equations Constrained to Triple Point Using Data for Eleven Gases and Three Metals (open access)

A Comparison of Two Melting-Pressure Equations Constrained to Triple Point Using Data for Eleven Gases and Three Metals

Parameters determined by a least-squares method for the reduced Simon equation and for a new, empirical melting equation.
Date: October 6, 1963
Creator: Goodwin, Robert D. & Weber, Lloyd A.
System: The UNT Digital Library
A Compilation of the Physical Equilibria and Related Properties of the Hydrogen-Carbon Monoxide System (open access)

A Compilation of the Physical Equilibria and Related Properties of the Hydrogen-Carbon Monoxide System

Graphical presentation of K-factors for eight isotherms, published data on the solid-vapor region, and a bibliography of approximately 450 references.
Date: May 1961
Creator: Drayer, D. E. & Flynn, T. M.
System: The UNT Digital Library
Construction of a Flashlamp-Pumped Dye Laser and an Acousto-Optik Modulator for Mode-Locking (open access)

Construction of a Flashlamp-Pumped Dye Laser and an Acousto-Optik Modulator for Mode-Locking

Design of a flashlamp-pumped dye laser capable of emitting light pulses 500 ns wide with a risetime of 300 ns.
Date: July 1971
Creator: Jennings, D. A.
System: The UNT Digital Library
Construction of a Large Transverse Electromagnetic Cell (open access)

Construction of a Large Transverse Electromagnetic Cell

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.
Date: February 1979
Creator: Decker, W. F. & Wilson, W. A.
System: The UNT Digital Library
Cryogenic Fluids Density Reference System: Provisional Accuracy Statement (1980) (open access)

Cryogenic Fluids Density Reference System: Provisional Accuracy Statement (1980)

Abstract: The improved Density Reference System, the reference densimeter, and the method of determining sample density are described. The uncertainty of the density reference system is + 0.055%. The contribution from the estimated systema -ic error in density was + 0.022%. The estimated uncertainty caused by random error is three times the standard deviation of 0.011% and is based on sixty-three measurements of the densities of saturated liquid methane. The total density uncertainty is taken to be the sum of the systematic and random errors. This applies to the density range of 400 to 480 kg/m at pressures from 0.8 to 4 bar absolute and temperatures between 109 and 128 K. This accuracy statement is expected to apply over ranges of at least 400 to 1000 kg/m3 in density, 77 to 300 K in temperature, and 0.8 to 7 bar in pressure though the accuracy over these ranges has not been verified.
Date: April 1981
Creator: Siegwarth, J. D. & LaBrecque, J. F.
System: The UNT Digital Library
Design and Error Analysis for the WR10 Thermal Noise Standard (open access)

Design and Error Analysis for the WR10 Thermal Noise Standard

From introduction: This note describes the design and error analysis of a WR10 thermal noise power standard. The standard is designed to operate at the boiling point of liquid nitrogen with a noise temperature accurate to plus or minus 1 K.
Date: December 1983
Creator: Daywitt, William C.
System: The UNT Digital Library
Design, Evaluation, and Use of a Reverberation Chamber for Performing Electromagnetic Susceptibility/Vulnerability Measurements (open access)

Design, Evaluation, and Use of a Reverberation Chamber for Performing Electromagnetic Susceptibility/Vulnerability Measurements

Abstract: This report presents the results of work at the National Bureau of Standards, Boulder, Colorado, to carefully evaluate, document, develop (when necessary), and describe the methodology for performing radiated susceptibility/vulnerability measurements using a reverberation chamber. The report describes the reverberation chamber theory of operation, construction, evaluation, functional operation, and use for performing immunity measurements. It includes an estimate of measurement uncertainties derived empirically from test results and from comparisons with anechoic chamber measurements. Finally, it discusses the limitations and advantages of the measurement technique to assist potential users in determining the applicability for this technique to their electromagnetic compatibility (EMC) measurement needs.
Date: April 1986
Creator: Crawford, M. L. & Koepke, Galen H.
System: The UNT Digital Library
Design for a Variable-Output-Coupling Far-Infrared Michelson Laser (open access)

Design for a Variable-Output-Coupling Far-Infrared Michelson Laser

Technique for varying the coupling of power from far-infrared gas lasers and the design and construction of these lasers.
Date: January 1971
Creator: Wells, J. S.; Evenson, K. M.; Matarrese, L. M.; Jennings, D. A. & Wichman, G. L.
System: The UNT Digital Library
Design of the National Bureau of Standards Isotropic Magnetic Field Meter (MFM-10) 300 kHz to 100 MHz (open access)

Design of the National Bureau of Standards Isotropic Magnetic Field Meter (MFM-10) 300 kHz to 100 MHz

From introduction: In this report the following will he discussed: (1) design consideration of the broadband magnetic field sensor, (2) overall design of the magnetic field meter, (3) performance of the meter, (4) calibration and operating procedures, (5) alignment and adjustment procedures, and (6) summary and conclusions.
Date: October 1985
Creator: Cruz, J. E.; Driver, L. D. & Kanda, Motohisa
System: The UNT Digital Library
Direct Measurement of the Electric Field of a Laser Pulse--Theory (open access)

Direct Measurement of the Electric Field of a Laser Pulse--Theory

From abstract: This paper presents the conflicts in the design and gives a solution. The complete evaluation requires assembly of the proposed apparatus to assess final accuracy.
Date: August 1985
Creator: Johnson, Eric Gunnar, Jr.
System: The UNT Digital Library
An Electric and Magnetic Field Sensor for Simultaneous Electromagnetic Near-Field Measurements -- Theory (open access)

An Electric and Magnetic Field Sensor for Simultaneous Electromagnetic Near-Field Measurements -- Theory

Abstract: This paper describes the theory of a single sensor to perform simultaneous electric and magnetic near-field measurements. The theory indicates that it is possible to obtain the magnetic-loop and electric-dipole currents using a loop terminated with identical loads at diametrically opposite points. The theory also indicates that it is possible to obtain an ideal load impedance for achieving equal electric and magnetic field responses of the loop. Preliminary experiments have been performed using plane waves to verify these results. Key words: electric field, electromagnetic interference, electromagnetic radiation, loop, magnetic field, near fields.
Date: April 1983
Creator: Kanda, Motohisa
System: The UNT Digital Library
Electrical Properties of Materials and Their Measurement at Low Temperatures (open access)

Electrical Properties of Materials and Their Measurement at Low Temperatures

Abstract: A review is given of the electrical resistance of materials at cryogenic temperatures. Measurement techniques, the data base, and uses of the data are presented. The emphasis is on metals and alloys of technological importance; a toxic which covers a large range of materials. Similarly, the treatment of theory and of measurement techniques is primarily for the user interested in the more practical aspects of the subject. In every instance, however, references are given which allow the reader to pursue the subject at any level.
Date: March 1982
Creator: Fickett, F. R.
System: The UNT Digital Library
Electromagnetic-Acoustic-Transducer/Synthetic-Aperture System for Thick-Weld Inspection (open access)

Electromagnetic-Acoustic-Transducer/Synthetic-Aperture System for Thick-Weld Inspection

Abstract: This report describes a system based on electromagnetic-acoustic transducers (EMATs) as an approach to automated nondestructive evaluation of thick weldments (>25 mm). Good signal-to-noise ratios, often a problem with EMATs, were possibTe through careful design of the transducers and associated electronic circuits and the use of signal averaging. At 454 kHz, the transducers produce shear-horizontal waves of approximately 7-mm wavelength in steel. The long wavelength permits determination of through-thickness flaw depth from the amplitudes of scattered ultrasonic waves. A minicomputer controlled transducer positioning and acquired the digitized ultrasonic waveforms for synthetic aperture processing. The synthetic aperture technique further improved signal quality and yielded flaw localization through the weld thickness. Measurements on artificial flaws demonstrated a detectability threshold of 0.5 mm (through thickness) and sizing ability up to 2.5 mm, in agreement with theoretical predictions. Details include the design of the transducers and electronics, as well as the mechanical positioner, signal processing algorithms, and complete computer program listing.
Date: 1984
Creator: Fortunko, C. M.; Schramm, R. E.; Moulder, J. C. & McColskey, J. D.
System: The UNT Digital Library
Electromagnetic Compatibility and Interference Metrology (open access)

Electromagnetic Compatibility and Interference Metrology

From abstract: The material included in this report is intended for a short course on electromagnetic compatibility/interference (EMC/EMI) metrology to be offered jointly by the staff of the Fields Characterization Group (723.03) and the Interference Characterization Group (723.04) of the Electromagnetic Fields Division (723). The purpose of this short course is to present a review of some of the radiated EMC/EMI measurement methods, to which the National Bureau of Standards (NBS) at Boulder, Colorado, has made significant contributions during the past two decades.
Date: July 1986
Creator: Ma, Mark T. & Kanda, M.
System: The UNT Digital Library
An Equation of State for Fluid Ethylene (open access)

An Equation of State for Fluid Ethylene

Abstract: A thermodynamic property formulation for ethylene, developed as a part of a joint industry-government project, is presented. The formulation includes an equation of state, vapor pressure equation, and equation for the ideal gas heat capacity. The coefficients were determined by a least squares fit of selected experimental data. Comparisons of property values calculated using the equation of state with measured values are given. The equation of state is not valid in the critical region (pc + 0.3 pc for temperatures of Tc + 0.05 Tc). Errors on the order of 20 percent for derived properties and 10 percent for density may be encountered near the critical point. Tables of the thermodynamic properties of ethylene for the liquid and vapor phases for temperatures from the freezing line to 450 K with pressures to 40 MPa are presented. The equation of state and its derivative and integral functions for calculating thermodynamic properties are included. Estimates of the accuracy of calculated properties are given. A guide for use of computer programs for the calculation of thermodynamic properties of ethylene with listings of subprograms and a sample program to illustrate the use and results of the program are included.
Date: July 1981
Creator: McCarty, Robert D. & Jacobsen, Richard T.
System: The UNT Digital Library