354 research outputs found

    NDE: An effective approach to improved reliability and safety. A technology survey

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    Technical abstracts are presented for about 100 significant documents relating to nondestructive testing of aircraft structures or related structural testing and the reliability of the more commonly used evaluation methods. Particular attention is directed toward acoustic emission; liquid penetrant; magnetic particle; ultrasonics; eddy current; and radiography. The introduction of the report includes an overview of the state-of-the-art represented in the documents that have been abstracted

    NASA Tech Briefs Index, 1977, volume 2, numbers 1-4

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    Announcements of new technology derived from the research and development activities of NASA are presented. Abstracts, and indexes for subject, personal author, originating center, and Tech Brief number are presented for 1977

    Detecting corrosion in aircraft components using neutron radiography

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1996.Includes bibliographical references (leaves 120-123).by David Walter Fink.M.S

    Bibliography of information on mechanics of structural failure (hydrogen embrittlement, protective coatings, composite materials, NDE)

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    This bibliography is comprised of approximately 1,600 reference citations related to four problem areas in the mechanics of failure in aerospace structures. The bibliography represents a search of the literature published in the period 1962-1976, the effort being largely limited to documents published in the United States. Listings are subdivided into the four problem areas: Hydrogen Embrittlement; Protective Coatings; Composite Materials; and Nondestructive Evaluation. An author index is included

    NASA Tech Briefs Index, 1978

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    Approximately 601 announcements of new technology derived from the research and development activities of the National Aeronautics and Space Administration are presented. Emphasis is placed on information considered likely to be transferrable across industrial, regional, or disciplinary lines. Subject matter covered includes: electronic components and circuits; electron systems; physical sciences; materials; life sciences; mechanics; machinery; fabrication technology; and mathematics and information sciences

    Modeling x-ray scattering process and applications of the scattering model

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    Computer modeling of nondestructive inspections with x-rays is proving to be a very useful tool for enhancing the performance of these techniques. Two x-ray based inspection techniques are considered in this study. The first is Radiographic Inspection , where an existing simulation model has been improved to account for scattered radiation effects. The second technique is Inspection with Compton backscattering , where a new simulation model has been developed;The effect of scattered radiation on a simulated radiographic image can be insignificant, equally important, or more important than the effect of the uncollided flux. Techniques to account for the scattered radiation effects include Monte Carlo techniques, and solving the particle transport equation for photons. However, these two techniques although accurate, are computationally expensive and hence inappropriate for use in computer simulation of radiography. A less accurate approach but computationally efficient is the principle of buildup factors. Traditionally, buildup factors are defined for monoenergetic photons of energies typical of a nuclear reactor. In this work I have expanded the definition of buildup factors to include a bremsstrahlung spectrum of photons with energies typically used in radiography (keV\u27s instead of MeV\u27s). This expansion of the definition relies on an intensive experimental work to measure buildup factors for a white spectrum of x-rays. I have also developed a monte carlo code to reproduce the measured buildup factors. The code was then converted to a parallel code and distributed on a network of workstations to reduce the execution time;The second inspection technique is based on Compton backscattering, where photons are scattered at large angles, more than 90 degrees. The importance of this technique arises when the inspected object is very large, or when access is limited to only one side of the specimen. The downside of detecting photons from backscattering is the low cross section for Compton scattering at such angles. However, several parameters can be optimized to enhance the probability of a backscattering event. These include the x-ray tube settings, the orientation of the inspected object and the angles of the incident and backscattered radiation. Optimizing these parameters can be made fast, inexpensive and more convenient by using a simulation code

    Cumulative index to NASA Tech Briefs, 1963-1967

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    Cumulative index to NASA survey on technology utilization of aerospace research outpu

    Assessment of state-of-the-art of in-service inspection methods for graphite epoxy composite structures on commercial transport aircraft

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    A survey was conducted to determine current in-service inspection practices for all types of aircraft structure and particularly for advanced composite structures. The survey consisted of written questionnaires to commercial airlines, visits to airlines, aircraft manufacturers, and government agencies, and a literature search. Details of the survey including visits, questions asked, a bibliography of reviewed literature and details of the results are reported. From the results, a current in-service inspection baseline and a preliminary inspection program for advanced composite structures is documented as appendices to the report

    Quantitative evaluation of material composition of composites using X-ray energy-dispersive NDE technique

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    In a wide range of situations the need for characterization of material properties of man-made and natural materials arises. These situations can include inspection during fabrication of material, and in-sexvice inspection of mechanical parts as they wear and near their design life. The need to characterize the material of interest involves all aspects of material performance, such as: the strength of the material, fracture toughness, density, hardness, material uniformity, and conductivity, etc. We present here a technique that is capable of quantitatively determining composition, density and material uniformity. It should be pointed out that no one technique can measure all properties of interest

    Exploration of several radiation-based analytical techniques to investigate chlorides and chlorides effects within concrete

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    Magister Scientiae - MScIn this study, the capabilities of Neutron Radiography (NRad) and -Tomography (NTomo), as well as X-ray Radiography (XRad) to investigate chlorides and chlorides corrosion effects within steel reinforced laboratory concrete samples are practically explored. Capabilities of Scanning Electron Microscopy (SEM), Prompt Gamma Neutron Activation Analysis (PGNAA), Particle Induced X-ray Emission (PIXE), Small-Angle Neutron Scattering (SANS), Neutron Diffraction (NDIFF) and X-ray Diffraction (XDIFF) analytical techniques are also explored through review of literature
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