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

Description: 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 determinat… more
Date: 1984
Creator: Fortunko, C. M.; Schramm, R. E.; Moulder, J. C. & McColskey, J. D.
Item Type: Refine your search to only Report
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Small Aperture Analysis of the Dual TEM Cell and an Investigation of Test Object Scattering in a Single TEM Cell

Description: Introduction: Small aperture theory is used to investigate the dual TEM cell. Analyzing coupling through an empty versus a loaded aperture leads to a model of dual TEM cell shielding effectiveness measurements. Small obstacle scattering yields results for both the field perturbation and the change in a cell's transmission line characteristics due to the presence of a test object in a TEM cell. In each case, theoretical values are compared to experimental data.
Date: 1984
Creator: Wilson, Perry F. & Ma, Mark T.
Item Type: Refine your search to only Report
open access

A Review of Supercritical Fluid Extraction

Description: Forward: The purpose of this report is to summarize the results obtained from a brief investigation of supercritical fluid extraction principles and applications. This study was one portion of a project funded by the U.S. Department of Energy, Office of Fossil Energy, contract nuriber DE-AI01076PR06010, in response to a preliminary proposal submitted by the authors. This report sometimes uses company trade naries to identify processes and patent holders. This usage implies no endorsement by HBS… more
Date: December 1983
Creator: Ely, James F. & Baker, Jolene K.
Item Type: Refine your search to only Report
open access

Introduction to STARPAC: the Standards Time Series and Regression Package

Description: From preface: STARPAC documentation is being published as a series of Technical Notes. This Note is the first in the series. It gives an overview of the STARPAC library, defines conventions used in the documentation, provides an example using STARPAC subroutines, and presents general background material. This Note includes information which is essential for using the STARPAC library, and users should be familiar with its contents before attempting to use any STARPAC subroutine.
Date: October 1983
Creator: Donaldson, Janet R. & Tryon, Peter V.
Item Type: Refine your search to only Report
open access

Nonlinear Least Squares Regression Using STARPAC: The Standards Time Series and Regression Package

Description: From preface: This Note documents 16 subroutines for nonlinear least squares regression. Twelve of these compute the least squares estimates, performing either weighted or unweighted analysis with either numerically approximated or user-supplied (analytic) derivatives. The other four are user-callable subroutines for two procedures used within the estimation code: the first selects optimum step sizes for approximating the partial derivatives of the model; and the second checks the validity of a… more
Date: October 1983
Creator: Donaldson, Janet R. & Tryon, Peter V.
Item Type: Refine your search to only Report
open access

Reference Flat Pulse Generator

Description: Introduction: A reference step-like pulse generator is described which has been developed at NBS. This generator can be used for accurately characterizing the step response of various kinds of trap ient recording equipment (oscilloscopes, waveform recorders, transient digitizers, etc.). Basic design principles are given as well as complete circuit diagrams and descriptions. An analysis of the output stage of the generator is presented together with the circuit models for developing a time-domai… more
Date: October 1983
Creator: Andrews, J. R.; Bell, B. A. & Baldwin, E. E.
Item Type: Refine your search to only Report
open access

Mineral Investigation of the Lime Hills, Narrows, and Sand Cove Wilderness Study Areas, Mohave County, Arizona

Description: From introduction: During 1981 the Bureau of Mines conducted a field investigation of the Bureau of Land Management's Lime Hills, Narrows, and Sand Cove Wilderness Study Areas (WSA's), Mohave County, Arizona as part of a joint effort with the Geological Survey to make a mineral survey of the area. Surface workings and outcrops were examined and samples taken from rock sections that appeared to represent most of the mineralized area. Complete analytical results and sample descriptions are availa… more
Date: 1983
Creator: Briggs, John P.
Item Type: Refine your search to only Report
open access

Mineral Investigation of the North End Roadless Area, Cochise County, Arizona

Description: From introduction: During the spring and fall of 1979 the U.S. Bureau of Mines made a mineral investigation of the North End Roadless Area, including a literature search, a search of claim records in the Cochise County courthouse and the State office of the Bureau of Land Management, a search for mining claims and mineralized zones, and examination of known mines and prospects. Local residents and officials of mining companies the U.S. Forest Service, and Arizona State government agencies provi… more
Date: 1983
Creator: Bigsby, Philip R.
Item Type: Refine your search to only Report
open access

National Uranium Resource Evaluation: Data Release on the Salton Sea Quadrangle, California and Arizona

Description: From objectives: In the Salton Sea Quadrangle, reported uranium occurrences were evaluated, and geologic environments thought to be favorable were examined. This report includes the field data collected during that work and a summary of the quadrangle geology and uranium favorability. This is the final report to be prepared on this quadrangle under the NURE program.
Date: October 1982
Creator: Chew, Randall T., III & Antrim, Donald R.
Item Type: Refine your search to only Report
open access

Reports on Investigations of Uranium Anomalies

Description: Introduction: The Hylas Zone, a northeast-trending belt of mylonite and ultramylonite, lies in the eastern Piedmont Province of Virginia and borders the northern end of the Richmond Basin (Fig. I-1). The north-trending Richmond Basin is 58 km long and a maximum of 16 km wide. Early indications of anomalous uranium concentrations in the region came from discussions with Jan Krason, GeoExplorers International, Denver, who had worked in the area. Examination of aerial radiometric data (Geodata Int… more
Date: October 1982
Creator: Goodknight, Craig S. & Burger, John A.
Item Type: Refine your search to only Report
open access

Uranium Mineralization in the Wilson Creek and Cranberry Gneisses and the Grandfather Mountain Formation, North Carolina and Tennessee

Description: From abstract: Detailed petrologic investigations were conducted at 74 anomalies that have surface radioactivities of 5 to 300 times background in the Grandfather Mountain region of North Carolina and Tennessee. One or more specimens of radioactive rock and one specimen of nonanomalous (barren) rock were taken for chemical analysis from each of the 74 sites.
Date: September 1982
Creator: Wagener, H. D. & McHone, J. Gregory
Item Type: Refine your search to only Report
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