Government of the United States of America, as Represented by the Secretary of Commerce

Other

National Institute of Standards and Technology

William P Dube

John M Moreland

Dale W Fitting

Thomas A Siewert

Glenn M Light

Richard D Albert

Cecil M Teller, Ii

Joseph David McColskey

Loren F Goodrich

Thomas E Capobianco

Martin C Renken

Raymond E Schramm

Kenneth W Fizer

Christopher M Fortunko

The present invention relates to x-ray diffraction measurement by using moving x-ray source x-ray diffraction. The invention comprises a raster-scanned x-ray source, a specimen, a collimator, and a detector. The x-ray source is electronically scanned which allows a complete image of the x-ray diffraction characteristics of the specimen to be produced. The specimen is placed remote from the x-ray source and the detector. The collimator is located directly in front of the detector. The x-rays are diffracted by the specimen at certain angles, which cause them to travel through the collimator and to the detector. The detector may be placed in any radial location relative to the specimen in order to take the necessary measurements. The detector can detect the intensity and/or the wavelength of the diffracted x-rays. All information needed to solve the Bragg equation as well as the Laue equations is available. The x-ray source may be scanned electronically or mechanically. The present invention is used to perform texture analysis and phase identification.

Method and apparatus for diffraction measurement using a scanning x-ray source

The present invention uses a high energy x-ray, neutron, or gamma source for monitoring the interface between a molten and solidified crystalline phase while in a furnace in a casting process. The radiation can also be used to determine the quality and orientation of the crystals in the crystalline phase. The invention uses the distinctive diffraction patterns produced by crystalline and amorphous phases to locate the interface.

Apparatus and method for monitoring casting process

A new ultrasonic method for measuring wall thickness and detecting material flaws in natural-gas pipelines, risers, and similar structures. The method is inherently suitable for the task, because it relies on the use of the natural gas as the coupling fluid for transmitting the probing ultrasonic signals into and out of the pipe wall. Furthermore, the method facilitates the operation of the inspection from the inside of the pipe. An experimental apparatus used to demonstrate the technical feasibility of this approach and provide experimental and theoretical evidence that support the claims is described. Significantly, it is shown that by the use of a diplexer, the same transducer can be used to generate and detect the probing ultrasonic signals. The same configuration is used in commercial ultrasonic inspection of oil pipelines where oil is the coupling fluid; but until now this method could not be used in natural gas pipelines due to the low specific acoustic impedance of natural gas.

Wall thickness and flow detection apparatus and method for gas pipelines

A method for thermal environment sensing utilizing superconducting materi finds utility in the production of low power cryogenic flow meters, bolometers, level detectors and other types of thermal environment sensors. A device for determining the first and second derivatives (dV/dI and d.sup.2 V/dI.sup.2) utilizes a ramped current until a set value of the first derivative (dV/dI) is achieved, the current supply being placed in a feedback mode to maintain the first derivative constant and monitoring any changes in the second derivative (d.sup.2 V/dI.sup.2) which indicate changes in the thermal environment. Alternatively, the second derivative is maintained constant and the first derivative is measured. Any parameter which is indicative of the non-linearity of the relationship between the voltage and the current can be utilized instead of the second derivative.

Thermal properties measurement using a superconductor sensor

A highly sensitive force detector using a tunneling junction as a strain gauge is disclosed. The tunneling junction is connected to a deflection member which receives the force to be measured. The junction is connected in a nulling circuit to a magnetic flux motor which generates a restoring force precisely equal to the force to be measured. The magnetic flux required by the flux motor to do so is measured by a SQUID, the output of which is directly proportional to the flux to be measured. The device has applications in pressure sensing, weighing, gravity measurements, detection of massive objects, and elsewhere.

Ultra-sensitive force detector employing servo-stabilized tunneling

A reference standard and a method for manufacturing a reference standard for use in calibrating an eddy current probe is disclosed. The reference standard is produced from a block of metal that is deformed by an indentation tool to provide a notch of prescribed dimensions. The reference standard is compressed along an axis substantially transverse to the longitudinal axis of the notch to substantially close the notch. A family of reference standards formed in this manner can be produced to calibrate an eddy current probe prior to use of the probe in evaluating metal components such as aircraft framework for the presence of fatigue cracks and the like.

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Denver, CO, United States of America

William P Dube