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Sample records for quantitative nondestructive evaluation

  1. Quantitative nondestructive evaluation: Requirements for tomorrow's reliability

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S.

    1991-01-01

    Quantitative Nondestructive Evaluation (QNDE) is the technology of measurement, analysis, and prediction of the state of material/structural systems for safety, reliability, and mission assurance. QNDE has impact on everyday life from the cars we drive, the planes we fly, the buildings we work or live in, literally to the infrastructure of our world. Here, researchers highlight some of the new sciences and technologies that are part of a safer, cost effective tomorrow. Specific technologies that are discussed are thermal QNDE of aircraft structural integrity, ultrasonic QNDE for materials characterization, and technology spinoffs from aerospace to the medical sector. In each case, examples are given of how new requirements result in enabling measurement technologies, which in turn change the boundaries of design/practice.

  2. The Nuclear Renaissance — Implications on Quantitative Nondestructive Evaluations

    NASA Astrophysics Data System (ADS)

    Matzie, Regis A.

    2007-03-01

    The world demand for energy is growing rapidly, particularly in developing countries that are trying to raise the standard of living for billions of people, many of whom do not even have access to electricity. With this increased energy demand and the high and volatile price of fossil fuels, nuclear energy is experiencing resurgence. This so-called nuclear renaissance is broad based, reaching across Asia, the United States, Europe, as well as selected countries in Africa and South America. Some countries, such as Italy, that have actually turned away from nuclear energy are reconsidering the advisability of this design. This renaissance provides the opportunity to deploy more advanced reactor designs that are operating today, with improved safety, economy, and operations. In this keynote address, I will briefly present three such advanced reactor designs in whose development Westinghouse is participating. These designs include the advanced passive PWR, AP1000, which recently received design certification for the US Nuclear Regulatory Commission; the Pebble Bed Modular reactor (PBMR) which is being demonstrated in South Africa; and the International Reactor Innovative and Secure (IRIS), which was showcased in the US Department of Energy's recently announced Global Nuclear Energy Partnership (GNEP), program. The salient features of these designs that impact future requirements on quantitative nondestructive evaluations will be discussed. Such features as reactor vessel materials, operating temperature regimes, and new geometric configurations will be described, and mention will be made of the impact on quantitative nondestructive evaluation (NDE) approaches.

  3. The Nuclear Renaissance - Implications on Quantitative Nondestructive Evaluations

    SciTech Connect

    Matzie, Regis A.

    2007-03-21

    The world demand for energy is growing rapidly, particularly in developing countries that are trying to raise the standard of living for billions of people, many of whom do not even have access to electricity. With this increased energy demand and the high and volatile price of fossil fuels, nuclear energy is experiencing resurgence. This so-called nuclear renaissance is broad based, reaching across Asia, the United States, Europe, as well as selected countries in Africa and South America. Some countries, such as Italy, that have actually turned away from nuclear energy are reconsidering the advisability of this design. This renaissance provides the opportunity to deploy more advanced reactor designs that are operating today, with improved safety, economy, and operations. In this keynote address, I will briefly present three such advanced reactor designs in whose development Westinghouse is participating. These designs include the advanced passive PWR, AP1000, which recently received design certification for the US Nuclear Regulatory Commission; the Pebble Bed Modular reactor (PBMR) which is being demonstrated in South Africa; and the International Reactor Innovative and Secure (IRIS), which was showcased in the US Department of Energy's recently announced Global Nuclear Energy Partnership (GNEP), program. The salient features of these designs that impact future requirements on quantitative nondestructive evaluations will be discussed. Such features as reactor vessel materials, operating temperature regimes, and new geometric configurations will be described, and mention will be made of the impact on quantitative nondestructive evaluation (NDE) approaches.

  4. Dual-band infrared thermography for quantitative nondestructive evaluation

    SciTech Connect

    Durbin, P.F.; Del Grande, N.K.; Dolan, K.W.; Perkins, D.E.; Shapiro, A.B.

    1993-04-01

    The authors have developed dual-band infrared (DBIR) thermography that is being applied to quantitative nondestructive evaluation (NDE) of aging aircraft. The DBIR technique resolves 0.2 degrees C surface temperature differences for inspecting interior flaws in heated aircraft structures. It locates cracks, corrosion sites, disbonds or delaminations in metallic laps and composite patches. By removing clutter from surface roughness effects, the authors clarify interpretation of subsurface flaws. To accomplish this, the authors ratio images recorded at two infrared bands, centered near 5 microns and 10 microns. These image ratios are used to decouple temperature patterns associated with interior flaw sites from spatially varying surface emissivity noise. They also discuss three-dimensional (3D) dynamic thermal imaging of structural flaws using dual-band infrared (DBIR) computed tomography. Conventional thermography provides single-band infrared images which are difficult to interpret. Standard procedures yield imprecise (or qualitative) information about subsurface flaw sites which are typically masked by surface clutter. They use a DBIR imaging technique pioneered at LLNL to capture the time history of surface temperature difference patterns for flash-heated targets. They relate these patterns to the location, size, shape and depth of subsurface flaws. They have demonstrated temperature accuracies of 0.2{degree}C, timing synchronization of 3 ms (after onset of heat flash) and intervals of 42 ms, between images, during an 8 s cooling (and heating) interval characterizing the front (and back) surface temperature-time history of an epoxy-glue disbond site in a flash-heated aluminum lap joint.

  5. Nondestructive evaluation

    SciTech Connect

    Martz, H.E.

    1997-02-01

    Research reported in the thrust area of nondestructive evaluation includes: advanced 3-D imaging technologies; new techniques in laser ultrasonic testing; infrared computed tomography for thermal NDE of materials, structures, sources, and processes; automated defect detection for large laser optics; multistatic micropower impulse radar imaging for nondestructive evaluation; and multi-modal NDE for AVLIS pod shielding components.

  6. Review of progress in quantitative NDE. [Nondestructive Evaluation (NDE)

    SciTech Connect

    Not Available

    1991-01-01

    This booklet is composed of abstracts from papers submitted at a meeting on quantitative NDE. A multitude of topics are discussed including analysis of composite materials, NMR uses, x-ray instruments and techniques, manufacturing uses, neural networks, eddy currents, stress measurements, magnetic materials, adhesive bonds, signal processing, NDE of mechanical structures, tomography,defect sizing, NDE of plastics and ceramics, new techniques, optical and electromagnetic techniques, and nonlinear techniques. (GHH)

  7. Nondestructive evaluations

    SciTech Connect

    Kulkarni, S.

    1993-03-01

    This report discusses Nondestructive Evaluation (NDE) thrust area which supports initiatives that advance inspection science and technology. The goal of the NDE thrust area is to provide cutting-edge technologies that have promise of inspection tools three to five years in the future. In selecting projects, the thrust area anticipates the needs of existing and future Lawrence Livermore National Laboratory (LLNL) programs. NDE provides materials characterization inspections, finished parts, and complex objects to find flaws and fabrication defects and to determine their physical and chemical characteristics. NDE also encompasses process monitoring and control sensors and the monitoring of in-service damage. For concurrent engineering, NDE becomes a frontline technology and strongly impacts issues of certification and of life prediction and extension. In FY-92, in addition to supporting LLNL programs and the activities of nuclear weapons contractors, NDE has initiated several projects with government agencies and private industries to study aging infrastructures and to advance manufacturing processes. Examples of these projects are (1) the Aging Airplanes Inspection Program for the Federal Aviation Administration, (2) Signal Processing of Acoustic Signatures of Heart Valves for Shiley, Inc.; and (3) Turbine Blade Inspection for the Air Force, jointly with Southwest Research Institute and Garrett. In FY-92, the primary contributions of the NDE thrust area, described in this report were in fieldable chemical sensor systems, computed tomography, and laser generation and detection of ultrasonic energy.

  8. Quantitative non-destructive evaluation of high-temperature superconducting materials

    SciTech Connect

    Achenbach, J.D.

    1990-09-15

    Even though the currently intensive research efforts on high-temperature superconducting materials have not yet converged on a well specified material, the strong indications are that such a material will be brittle, anisotropic, and may contain many flaws such as microcracks and voids at grain boundaries. Consequently, practical applications of high temperature superconducting materials will require a very careful strength analysis based on fracture mechanics considerations. Because of the high sensitivity of the strength of such materials to the presence of defects, methods of quantitative non-destructive evaluation may be expected to play an important role in strength determinations. This proposal is concerned with the use of ultrasonic methods to detect and characterize isolated cracks, clusters of microcracks and microcracks distributed throughout the material. Particular attention will be devoted to relating ultrasonic results directly to deterministic and statistical linear elastic fracture mechanics considerations.

  9. Quantitative non-destructive evaluation of high-temperature superconducting materials

    SciTech Connect

    Achenbach, J.D.

    1991-06-14

    Even though the currently intensive research efforts on high- temperature superconducting materials have not yet converged on a well specified practical material, the indications are that such a material may be quite brittle, anisotropic, and may contain many flaws such as microcracks and voids at grain boundaries. Consequently, practical applications of high temperature superconducting materials will require a very careful strength analysis based on fracture mechanics considerations. Because of the high sensitivity of the strength of such materials to the presence of defects, methods of quantitative non-destructive evaluation may be expected to play an important role in strength determinations. This proposal is concerned with the use of ultrasonic methods to detect and characterize isolated cracks, clusters of microcracks and microcracks distributed throughout the material. Particular attention has been, and will continue to be devoted to relating ultrasonic results to fracture mechanics considerations.

  10. Physical interpretation and development of ultrasonic nondestructive evaluation techniques applied to the quantitative characterization of textile composite materials

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1993-01-01

    In this Progress Report, we describe our current research activities concerning the development and implementation of advanced ultrasonic nondestructive evaluation methods applied to the characterization of stitched composite materials and bonded aluminum plate specimens. One purpose of this investigation is to identify and characterize specific features of polar backscatter interrogation which enhance the ability of ultrasound to detect flaws in a stitched composite laminate. Another focus is to explore the feasibility of implementing medical linear array imaging technology as a viable ultrasonic-based nondestructive evaluation method to inspect and characterize bonded aluminum lap joints. As an approach to implementing quantitative ultrasonic inspection methods to both of these materials, we focus on the physics that underlies the detection of flaws in such materials.

  11. Ultrasonic Nondestructive Evaluation Techniques Applied to the Quantitative Characterization of Textile Composite Materials

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1997-01-01

    In this Progress Report, we describe our further development of advanced ultrasonic nondestructive evaluation methods applied to the characterization of anisotropic materials. We present images obtained from experimental measurements of ultrasonic diffraction patterns transmitted through water only and transmitted through water and a thin woven composite. All images of diffraction patterns have been included on the accompanying CD-ROM in the JPEG format and Adobe TM Portable Document Format (PDF), in addition to the inclusion of hardcopies of the images contained in this report. In our previous semi-annual Progress Report (NAG 1-1848, December, 1996), we proposed a simple model to simulate the effect of a thin woven composite on an insonifying ultrasonic pressure field. This initial approach provided an avenue to begin development of a robust measurement method for nondestructive evaluation of anisotropic materials. In this Progress Report, we extend that work by performing experimental measurements on a single layer of a five-harness biaxial woven composite to investigate how a thin, yet architecturally complex, material interacts with the insonifying ultrasonic field. In Section 2 of this Progress Report we describe the experimental arrangement and methods for data acquisition of the ultrasonic diffraction patterns upon transmission through a thin woven composite. We also briefly describe the thin composite specimen investigated. Section 3 details the analysis of the experimental data followed by the experimental results in Section 4. Finally, a discussion of the observations and conclusions is found in Section 5.

  12. Quantitative broadband ultrasonic backscatter - An approach to nondestructive evaluation in acoustically inhomogeneous materials

    NASA Technical Reports Server (NTRS)

    Odonnell, M.; Miller, J. G.

    1981-01-01

    The use of a broadband backscatter technique to obtain the frequency dependence of the longitudinal-wave ultrasonic backscatter coefficient from a collection of scatterers in a solid is investigated. Measurements of the backscatter coefficient were obtained over the range of ultrasonic wave vector magnitude-glass sphere radius product between 0.1 and 3.0 from model systems consisting of dilute suspensions of randomly distributed crown glass spheres in hardened polyester resin. The results of these measurements were in good agreement with theoretical prediction. Consequently, broadband measurements of the ultrasonic backscatter coefficient may represent a useful approach toward characterizing the physical properties of scatterers in intrinsically inhomogeneous materials such as composites, metals, and ceramics, and may represent an approach toward nondestructive evaluation of these materials.

  13. Ultrasonic Nondestructive Evaluation Techniques Applied to the Quantitative Characterization of Textile Composite Materials

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1998-01-01

    An overall goal of this research has been to enhance our understanding of the scientific principles necessary to develop advanced ultrasonic nondestructive techniques for the quantitative characterization of advanced composite structures. To this end, we have investigated a thin woven composite (5-harness biaxial weave). We have studied the effects that variations of the physical parameters of the experimental setup can have on the ultrasonic determination of the material properties for this thin composite. In particular, we have considered the variation of the nominal center frequency and the f-number of the transmitting transducer which in turn address issues such as focusing and beam spread of ultrasonic fields. This study has employed a planar, two-dimensional, receiving pseudo-array that has permitted investigation of the diffraction patterns of ultrasonic fields. Distortion of the ultrasonic field due to the spatial anisotropy of the thin composite has prompted investigation of the phenomenon of phase cancellation at the face of a finite-aperture, piezoelectric receiver. We have performed phase-sensitive and phase-insensitive analyses to provide a measure of the amount of phase cancellation at the face of a finite-aperture, piezoelectric receiver. The pursuit of robust measurements of received energy (i.e., those not susceptible to phase cancellation at the face of a finite-aperture, piezoelectric receiver) supports the development of robust techniques to determine material properties from measure ultrasonic parameters.

  14. Laser optoacoustic method for quantitative nondestructive evaluation of the subsurface damage depth in ground silicon wafers

    NASA Astrophysics Data System (ADS)

    Podymova, N. B.; Karabutov, A. A.; Cherepetskaya, E. B.

    2014-08-01

    This paper is a report on the novel laser optoacoustic method for nondestructive evaluation of the depth of the subsurface damage in ground single-crystal silicon wafers. It is based on different mechanisms of laser excitation of ultrasound by absorption of Q-switched Nd:YAG laser pulses at the fundamental wavelength: the concentration-deformation mechanism in the undamaged single-crystal silicon and the thermoelastic one in the subsurface damaged layer. Due to the uniform heating of the whole damaged layer during the laser pulse action the amplitude of the compression phase of the laser-induced ultrasonic signal is proportional to the damaged depth. The rarefaction phase of this signal arises by absorption of the remaining laser energy in the single-crystal silicon beneath the damaged layer. The empirical relation between the depth of the subsurface damage and the ratio of the amplitudes of compression and rarefaction phases of the laser-induced ultrasonic signal can be fitted by a linear function within the depth variation and the corresponding spread of the signal amplitudes. The proposed method attracts some interest for in situ control of the solid surface condition that is important in different tasks of linear and nonlinear optics.

  15. A Bayesian quantitative nondestructive evaluation (QNDE) approach to estimating remaining life of aging pressure vessels and piping*

    NASA Astrophysics Data System (ADS)

    Fong, J. T.; Filliben, J. J.; Heckert, N. A.; Guthrie, W. F.

    2013-01-01

    In this paper, we use a Bayesian quantitative nondestructive evaluation (QNDE) approach to estimating the remaining life of aging structures and components. Our approach depends on in-situ NDE measurements of detectable crack lengths and crack growth rates in a multi-crack region of an aging component as a basis for estimating the mean and standard deviation of its remaining life. We introduce a general theory of crack growth involving multiple cracks such that the mean and standard deviation of the initial crack lengths can be directly estimated from NDEmeasured crack length data over a period of several inspection intervals. A numerical example using synthetic NDE data for high strength steels is presented to illustrate this new methodology.

  16. Quantitative non-destructive evaluation of high-temperature superconducting materials. Progress report, September 1, 1990--August 31, 1991

    SciTech Connect

    Achenbach, J.D.

    1991-06-14

    Even though the currently intensive research efforts on high- temperature superconducting materials have not yet converged on a well specified practical material, the indications are that such a material may be quite brittle, anisotropic, and may contain many flaws such as microcracks and voids at grain boundaries. Consequently, practical applications of high temperature superconducting materials will require a very careful strength analysis based on fracture mechanics considerations. Because of the high sensitivity of the strength of such materials to the presence of defects, methods of quantitative non-destructive evaluation may be expected to play an important role in strength determinations. This proposal is concerned with the use of ultrasonic methods to detect and characterize isolated cracks, clusters of microcracks and microcracks distributed throughout the material. Particular attention has been, and will continue to be devoted to relating ultrasonic results to fracture mechanics considerations.

  17. Quantitative non-destructive evaluation of high-temperature superconducting materials. Technical progress report, September 1, 1989--August 30, 1990

    SciTech Connect

    Achenbach, J.D.

    1990-09-15

    Even though the currently intensive research efforts on high-temperature superconducting materials have not yet converged on a well specified material, the strong indications are that such a material will be brittle, anisotropic, and may contain many flaws such as microcracks and voids at grain boundaries. Consequently, practical applications of high temperature superconducting materials will require a very careful strength analysis based on fracture mechanics considerations. Because of the high sensitivity of the strength of such materials to the presence of defects, methods of quantitative non-destructive evaluation may be expected to play an important role in strength determinations. This proposal is concerned with the use of ultrasonic methods to detect and characterize isolated cracks, clusters of microcracks and microcracks distributed throughout the material. Particular attention will be devoted to relating ultrasonic results directly to deterministic and statistical linear elastic fracture mechanics considerations.

  18. Quantitative nondestructive in-service evaluation of stay cables of cable-stayed bridges: methods and practical experience

    NASA Astrophysics Data System (ADS)

    Weischedel, Herbert R.; Hoehle, Hans-Werner

    1995-05-01

    Stay cables of cable-stayed bridges have corrosion protection systems that can be elaborate. For example, such a system may simply consist of one or several coats of paint, or--more complex--of plastic pipes that are wrapped with tape and filled with grout. Frequently, these corrosion protection systems prevent visual inspections. Therefore, alternative nondestructive examination methods are called for. For example, modern dual-function electromagnetic (EM) instruments allow the simultaneous detection of external and internal localized flaws (such as external and internal broken wires and corrosion piting) and the measurement of loss of metallic cross-sectional area (typically caused by external or internal corrosion or wear). Initially developed for mining and skiing applications, these instruments have been successfully used for the inspection of stays of cable-stayed bridges, and for the inspection of guys of smoke stacks, flare stacks, broadcast towers, suspended roofs, etc. As a rule, guys and bridge cables are not subjected to wear and bending stresses. However, their safety can be compromised by corrosion caused by the failure of corrosion protection systems. Furthermore, live loads and wind forces create intermittent tensile stresses that can cause fatigue breaks of wires. This paper discusses the use of dual-function EM instruments for the detection and the nondestructive quantitative evaluation of cable deterioration. It explains the underlying principles. Experiences with this method together with field inspection results will be presented.

  19. [Nondestructive Evaluation (NDE) Capabilities

    NASA Technical Reports Server (NTRS)

    Born, Martin

    2010-01-01

    These poster boards display the United Space Alliance's (USA) systems and equipment used for Nondestructive Evaluation. These include: (1) the Robotic Inspection Facility, (2) CAT-Scan and Laminography, (3) Laser Surface Profilometry, (4) Remote Eddy Current, (5) Ultrasonic Phased Array, (7) Infrared Flash Thermography, and (8) Backscatter X-Ray (BSX)

  20. Ultrasonic Nondestructive Evaluation Techniques Applied to the Quantitative Characterization of Textile Composite Materials

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1997-01-01

    In this Progress Report, we describe our recent developments of advanced ultrasonic nondestructive evaluation methods applied to the characterization of anisotropic materials. We present images obtained from experimental measurements of ultrasonic diffraction patterns for a thin woven composite in an immersion setup. In addition, we compare apparent signal loss measurements of the thin woven composite for phase-sensitive and phase-insensitive detection methods. All images of diffraction patterns have been included on the accompanying CD-ROM in the Adobe(Trademark) Portable Document Format (PDF). Due to the extensive amount of data, however, hardcopies of only a small representative selection of the images are included within the printed report. This Progress Report presents experimental results that support successful implementation of single element as well as one and two-dimensional ultrasonic array technologies for the inspection of textile composite structures. In our previous reports, we have addressed issues regarding beam profiles of ultrasonic pressure fields transmitted through a water reference path and transmitted through a thin woven composite sample path. Furthermore, we presented experimental results of the effect of a thin woven composite on the magnitude of an insonifying ultrasonic pressure field. In addition to the study of ultrasonic beam profiles, we consider issues relevant to the application of single-element, one-dimensional, and two-dimensional array technologies towards probing the mechanical properties of advanced engineering composites and structures. We provide comparisons between phase-sensitive and phase-insensitive detection methods for determination of textile composite structure parameters. We also compare phase-sensitive and phase-insensitive - - ---- ----- apparent signal loss measurements in an effort to study the phenomenon of phase cancellation at the face of a finite-aperture single-element receiver. Furthermore, in this Progress Report we extend our work on ultrasonic beam profile issues through investigation of the phase fronts of the pressure field. In Section H of this Progress Report we briefly describe the experimental arrangement and methods for data acquisition of the ultrasonic diffraction patterns upon transmission through a thin woven composite. Section III details the analysis of the experimental data followed by the experimental results in Section IV. Finally, a discussion of the observations and conclusions is found in Section V.

  1. Quantitative non-destructive evaluation of composite materials based on ultrasonic wave propagation

    NASA Technical Reports Server (NTRS)

    Miller, J. G.

    1984-01-01

    The size, shape, and orientation of damage correlates well between the polar backscatter technique and the deply technique. There is good quantitative correlation between the areas of damage indicated by the two techniques. These results suggest that the polar backscatter technique is sensitive to specific orientations of damage. The polar backscatter technique provides a good qualitative image of the size and shape of the largest zone of damage in each of the principal orientations. A quantitative estimate of the extent of these largest damage zones is obtained from the polar backscatter technique. The selective sensitivity of polar backscatter provides a useful tool for further studies of the mechanisms of impact damage in graphite fiber reinforced composite laminates.

  2. Advances in nondestructive evaluation technology

    NASA Technical Reports Server (NTRS)

    Heyman, J. S.

    1982-01-01

    Research at NASA Langley's Materials Characterization Instrumentation Section has followed the philosophy of improving the science base of nondestructive evaluation and advancing the state of the art of quantitative interpretability of physical measurements of materials. Details of several R&D programs choosen to highlight the last several years are given. Applications of these technologies are presented in the area of stress measurement, characterization of metal heat treatment, and evaluation of material internal structure. A second focus of the program is on quantitative transducers/measurements that have resulted in better data in irregular inhomogeneous materials such as composites. Examples are presented of new capabilities resulting from these advances that include fatigue and impact damage evaluation.

  3. Quantitative non-destructive evaluation of porous composite materials based on ultrasonic wave propagation

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1988-01-01

    Two complementary ultrasonic techniques for characterizing porosity in fiber-reinforced composite laminates are evaluated. Five uniaxial graphite-fiber/epoxy-matrix composites having a range of 1 to 8 percent volume fraction of solid glass inclusions to model porosity were investigated. In one technique, signal loss was measured in transmission mode and slope of attenuation, obtained from the first order coefficient of a two-parameter polynomial fit about the center frequency of the useful bandwidth, was used as the ultrasonic parameter to characterize the porosity. The results of these transmission mode measurements displayed a good correlation between the volume fraction of porosity and the slope of attenuation. Integrated polar backscatter was used as a second ultrasonic parameter for the characterization of the porosity in these samples. A single transducer insonified the samples and measured the resulting backscatter at a polar angle of 30 deg with respect to the normal of the sample surface with the azimuthal angles centered at 0 deg with respect to the fiber orientation (i.e., along the fibers). Integrated polar backscatter also displayed good correlation with the volume fraction of porosity.

  4. Nondestructive evaluation technique guide

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1973-01-01

    A total of 70 individual nondestructive evaluation (NDE) techniques are described. Information is presented that permits ease of comparison of the merits and limitations of each technique with respect to various NDE problems. An NDE technique classification system is presented. It is based on the system that was adopted by the National Materials Advisory Board (NMAB). The classification system presented follows the NMAB system closely with the exception of additional categories that have been added to cover more advanced techniques presently in use. The rationale of the technique is explained. The format provides for a concise description of each technique, the physical principles involved, objectives of interrogation, example applications, limitations of each technique, a schematic illustration, and key reference material. Cross-index tabulations are also provided so that particular NDE problems can be referred to appropriate techniques.

  5. Physical interpretation and development of ultrasonic nondestructive evaluation techniques applied to the quantitative characterization of textile composite materials

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1992-01-01

    The development and implementation of advanced ultrasonic nondestructive evaluation methods applied to the characterization of composite materials requires a better understanding of the physics underlying the interaction of ultrasound with the material. The purpose of this investigation is to identify and characterize the features of complex, three dimensional materials that limit the ability of ultrasound to detect flaws in this broad class of emerging materials. In order to explore the interaction of ultrasound with such complex media, we investigate the characteristics of ultrasonic fields which have propagated through samples with complex geometries and/or internal architecture. We focus on the physics that underlies the detection of flaws in such materials.

  6. Quantitative Ultrasound for Nondestructive Characterization of Engineered Tissues and Biomaterials.

    PubMed

    Dalecki, Diane; Mercado, Karla P; Hocking, Denise C

    2016-03-01

    Non-invasive, non-destructive technologies for imaging and quantitatively monitoring the development of artificial tissues are critical for the advancement of tissue engineering. Current standard techniques for evaluating engineered tissues, including histology, biochemical assays and mechanical testing, are destructive approaches. Ultrasound is emerging as a valuable tool for imaging and quantitatively monitoring the properties of engineered tissues and biomaterials longitudinally during fabrication and post-implantation. Ultrasound techniques are rapid, non-invasive, non-destructive and can be easily integrated into sterile environments necessary for tissue engineering. Furthermore, high-frequency quantitative ultrasound techniques can enable volumetric characterization of the structural, biological, and mechanical properties of engineered tissues during fabrication and post-implantation. This review provides an overview of ultrasound imaging, quantitative ultrasound techniques, and elastography, with representative examples of applications of these ultrasound-based techniques to the field of tissue engineering. PMID:26581347

  7. Physical interpretation and development of ultrasonic nondestructive evaluation techniques applied to the quantitative characterization of textile composite materials

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1994-01-01

    In this Progress Report, we describe our continuing research activities concerning the development and implementation of advanced ultrasonic nondestructive evaluation methods applied to the inspection and characterization of complex composite structures. We explore the feasibility of implementing medical linear array imaging technology as a viable ultrasonic-based nondestructive evaluation method to inspect and characterize complex materials. As an initial step toward the application of linear array imaging technology to the interrogation of a wide range of complex composite structures, we present images obtained using an unmodified medical ultrasonic imaging system of two epoxy-bonded aluminum plate specimens, each with intentionally disbonded regions. These images are compared with corresponding conventional ultrasonic contact transducer measurements in order to assess whether these images can detect disbonded regions and provide information regarding the nature of the disbonded region. We present a description of a standoff/delay fixture which has been designed, constructed, and implemented on a Hewlett-Packard SONOS 1500 medical imaging system. This standoff/delay fixture, when attached to a 7.5 MHz linear array probe, greatly enhances our ability to interrogate flat plate specimens. The final section of this Progress Report describes a woven composite plate specimen that has been specially machined to include intentional flaws. This woven composite specimen will allow us to assess the feasibility of applying linear array imaging technology to the inspection and characterization of complex textile composite materials. We anticipate the results of this on-going investigation may provide a step toward the development of a rapid, real-time, and portable method of ultrasonic inspection and characterization based on linear array technology.

  8. Physical interpretation and development of ultrasonic nondestructive evaluation techniques applied to the quantitative characterization of textile composite materials

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1995-01-01

    In this Progress Report, the author describes the continuing research to explore the feasibility of implementing medical linear array imaging technology as a viable ultrasonic-based nondestructive evaluation method to inspect and characterize complex materials. Images obtained using an unmodified medical ultrasonic imaging system of a bonded aluminum plate sample with a simulated disbond region are presented. The disbond region was produced by adhering a piece of plain white paper to a piece of cellophane tape and applying the paper-tape combination to one of the aluminum plates. Because the area under the paper was not adhesively bonded to the aluminum plate, this arrangement more closely simulates a disbond. Images are also presented for an aluminum plate sample with an epoxy strip adhered to one side to help provide information for the interpretation of the images of the bonded aluminum plate sample containing the disbond region. These images are compared with corresponding conventional ultrasonic contact transducer measurements in order to provide information regarding the nature of the disbonded region. The results of this on-going investigation may provide a step toward the development of a rapid, real-time, and portable method of ultrasonic inspection and characterization based on linear array technology. In Section 2 of this Progress Report, the preparation of the aluminum plate specimens is described. Section 3 describes the method of linear array imaging. Sections 4 and 5 present the linear array images and results from contact transducer measurements, respectively. A discussion of the results are presented in Section 6.

  9. Fast, Quantitative, and Nondestructive Evaluation on Hydrided LWR Fuel Cladding by Small Angle Incoherent Neutron Scattering of Hydrogen

    DOE PAGESBeta

    Littrell, Ken; Parish, Chad M

    2015-01-01

    A non-destructive neutron scattering method to precisely measure the uptake of hydrogen and the distribution of hydride precipitates in light water reactor (LWR) fuel cladding was developed. Zircaloy-4 cladding used in commercial LWRs was used to produce hydrided specimens. The hydriding apparatus consists of a closed stainless steel vessel that contains Zr alloy specimens and hydrogen gas. Following hydrogen charging, the hydrogen content of the hydrided specimens was measured using the vacuum hot extraction method, by which the samples with desired hydrogen concentration were selected for the neutron study. Optical microscopy shows that our hydriding procedure results in uniform distributionmore » of circumferential hydrides across the wall. Small angle neutron incoherent scattering was performed in the High Flux Isotope Reactor at Oak Ridge National Laboratory. Our study demonstrates that the hydrogen in commercial Zircaloy-4 cladding can be measured very accurately in minutes by this nondestructive method over a wide range of hydrogen concentrations from a very small amount ( 20 ppm) to over 1000 ppm. The hydrogen distribution in a tube sample was obtained by scaling the neutron scattering rate with a factor determined by a calibration process using standard, destructive direct chemical analysis methods on the specimens. This scale factor can be used in future tests with unknown hydrogen concentrations, thus providing a nondestructive method for absolute hydrogen concentration determination.« less

  10. Fast, Quantitative, and Nondestructive Evaluation on Hydrided LWR Fuel Cladding by Small Angle Incoherent Neutron Scattering of Hydrogen

    SciTech Connect

    Littrell, Ken; Parish, Chad M

    2015-01-01

    A non-destructive neutron scattering method to precisely measure the uptake of hydrogen and the distribution of hydride precipitates in light water reactor (LWR) fuel cladding was developed. Zircaloy-4 cladding used in commercial LWRs was used to produce hydrided specimens. The hydriding apparatus consists of a closed stainless steel vessel that contains Zr alloy specimens and hydrogen gas. Following hydrogen charging, the hydrogen content of the hydrided specimens was measured using the vacuum hot extraction method, by which the samples with desired hydrogen concentration were selected for the neutron study. Optical microscopy shows that our hydriding procedure results in uniform distribution of circumferential hydrides across the wall. Small angle neutron incoherent scattering was performed in the High Flux Isotope Reactor at Oak Ridge National Laboratory. Our study demonstrates that the hydrogen in commercial Zircaloy-4 cladding can be measured very accurately in minutes by this nondestructive method over a wide range of hydrogen concentrations from a very small amount ( 20 ppm) to over 1000 ppm. The hydrogen distribution in a tube sample was obtained by scaling the neutron scattering rate with a factor determined by a calibration process using standard, destructive direct chemical analysis methods on the specimens. This scale factor can be used in future tests with unknown hydrogen concentrations, thus providing a nondestructive method for absolute hydrogen concentration determination.

  11. Fast, quantitative, and nondestructive evaluation of hydrided LWR fuel cladding by small angle incoherent neutron scattering of hydrogen

    NASA Astrophysics Data System (ADS)

    Yan, Y.; Qian, S.; Littrell, K.; Parish, C. M.; Plummer, L. K.

    2015-05-01

    A nondestructive neutron scattering method to precisely measure the uptake of hydrogen and the distribution of hydride precipitates in light water reactor (LWR) fuel cladding was developed. Zircaloy-4 cladding used in commercial LWRs was used to produce hydrided specimens. The hydriding apparatus consists of a closed stainless-steel vessel that contains Zr alloy specimens and hydrogen gas. Following hydrogen charging, the hydrogen content of the hydrided specimens was measured using the vacuum hot extraction method, by which the samples with desired hydrogen concentrations were selected for the neutron study. Optical microscopy shows that our hydriding procedure results in uniform distribution of circumferential hydrides across the wall thickness. Small angle neutron incoherent scattering was performed in the High Flux Isotope Reactor at Oak Ridge National Laboratory. Our study demonstrates that the hydrogen in commercial Zircaloy-4 cladding can be measured very accurately in minutes by this nondestructive method over a wide range of hydrogen concentrations from a very small amount (≈20 ppm) to over 1000 ppm. The hydrogen distribution in a tube sample was obtained by scaling the neutron scattering rate with a factor determined by a calibration process using standard, destructive direct chemical analysis methods on the specimens. This scale factor can be used in future tests with unknown hydrogen concentrations, thus providing a nondestructive method for determining absolute hydrogen concentrations.

  12. Overview of nondestructive evaluation technologies

    SciTech Connect

    Thomas, G.

    1995-04-01

    The infrastructure in the US and the world is aging. There is an increasing awareness of the need to assess the severity of the damage occurring to the infrastructure. Limited resources preclude the replacement of all structures that need repairs or have exceeded their life times. Methods to assess the amount and severity of damage are crucial to implementing a systematic, cost effective approach to repair and/or replace the damaged structures. The challenges of inspecting aging structures without impairing their usefulness rely on a variety of technologies and techniques for nondestructive evaluation (NDE). This paper will briefly describe several nondestructive evaluation technologies that are required for inspecting a variety of systems and structures.

  13. Nondestructive evaluation of advanced ceramics

    NASA Technical Reports Server (NTRS)

    Klima, Stanley J.; Kautz, Harold E.

    1988-01-01

    A review is presented of Lewis Research Center efforts to develop nondestructive evaluation techniques for characterizing advanced ceramic materials. Various approaches involved the use of analytical ultrasonics to characterize monolythic ceramic microstructures, acousto-ultrasonics for characterizing ceramic matrix composites, damage monitoring in impact specimens by microfocus X-ray radiography and scanning ultrasonics, and high resolution computed X-ray tomography to identify structural features in fiber reinforced ceramics.

  14. An approach for relating the results of quantitative nondestructive evaluation to intrinsic properties of high-performance materials

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1990-01-01

    One of the most difficult problems the manufacturing community has faced during recent years has been to accurately assess the physical state of anisotropic high-performance materials by nondestructive means. In order to advance the design of ultrasonic nondestructive testing systems, a more fundamental understanding of how ultrasonic waves travel and interact within the anisotropic material is needed. The relationship between the ultrasonic and engineering parameters needs to be explored to understand their mutual dependence. One common denominator is provided by the elastic constants. The preparation of specific graphite/epoxy samples to be used in the experimental investigation of the anisotropic properties (through the measurement of the elastic stiffness constants) is discussed. Accurate measurements of these constants will depend upon knowledge of refraction effects as well as the direction of group velocity propagation. The continuing effort for the development of improved visualization techniques for physical parameters is discussed. Group velocity images are presented and discussed. In order to fully understand the relationship between the ultrasonic and the common engineering parameters, the physical interpretation of the linear elastic coefficients (the quantities that relate applied stresses to resulting strains) are discussed. This discussion builds a more intuitional understanding of how the ultrasonic parameters are related to the traditional engineering parameters.

  15. Nondestructive evaluation of structural ceramics

    NASA Technical Reports Server (NTRS)

    Klima, Stanley J.; Baaklini, George Y.; Abel, Phillip B.

    1987-01-01

    A review is presented on research and development of techniques for nondestructive evaluation and characterization of advanced ceramics for heat engine applications. Highlighted in this review are Lewis Research Center efforts in microfocus radiography, scanning laser acoustic microscopy (SLAM), scanning acoustic microscopy (SAM), scanning electron acoustic microscopy (SEAM), and photoacoustic microscopy (PAM). The techniques were evaluated by applying them to research samples of green and sintered silicon nitride and silicon carbide in the form of modulus-of-rupture bars containing seeded voids. Probabilities of detection of voids were determined for diameters as small as 20 microns for microfucus radiography, SLAM, and SAM. Strengths and limitations of the techniques for ceramic applications are identified. Application of ultrasonics for characterizing ceramic microstructures is also discussed.

  16. Nondestructive evaluation of electrodeposited chromium

    NASA Astrophysics Data System (ADS)

    Todaro, Mark E.

    1992-11-01

    Benet Laboratories is pursuing methods for nondestructively evaluating the quality and adhesion of electrodeposited chromium coatings on the bore of large caliber gun tubes. The Army currently has no suitable means for testing such coatings nondestructively. A poor quality or poorly adherent coating shows up only when several test rounds are fired through the tube, removing portions of the coating and exposing the steel underneath. Recent in-house work has investigated both photothermal and ultrasonic methods. The photothermal method involves briefly heating the surface of the chromium with a laser pulse. After the initial heating, the surface temperature decreases as heat diffuses into the coating and substrate. The characteristics of the coating, interface, and substrate affect the surface temperature profile in distinct ways. The temperature of the surface can be measured by observing the emitted infrared radiation with a focused detector or an infrared scanner. Although no experimental data using the photothermal technique has been obtained yet, a one-dimensional finite difference algorithm was used to model temperature changes on the surface of a chromium coating on steel due to an incident energy pulse. The model verifies that with a suitable choice of laser pulse width, one could measure the thermal characteristics of the coating and detect the presence of a thermal discontinuity at the interface.

  17. Problems associated with nondestructive evaluation of bridges

    NASA Astrophysics Data System (ADS)

    Prine, David W.

    1995-05-01

    The US has 542,000 bridges that consume billions of dollars per year in construction, rehabilitation, and maintenance funds and which are the lifelines of US commerce. The 1992 ISTEA (Intermodal Surface Transportation Efficiency Act) mandates the implementation of a quantitative computerized bridge management system by 1996. A prime need of such a system are quantitative bridge inspection methods to feed accurate reliable condition information to the huge database of bridges. Nondestructive evaluation (NDE) will fill a critical need in the implementation of effective bridge management. However, many serious barriers exist to the widespread routine application of this technology to bridges. This paper provides an overview of the typical problems associated with applying NDE to bridges.

  18. Assessment of and standardization for quantitative nondestructive test

    NASA Technical Reports Server (NTRS)

    Neuschaefer, R. W.; Beal, J. B.

    1972-01-01

    Present capabilities and limitations of nondestructive testing (NDT) as applied to aerospace structures during design, development, production, and operational phases are assessed. It will help determine what useful structural quantitative and qualitative data may be provided from raw materials to vehicle refurbishment. This assessment considers metal alloys systems and bonded composites presently applied in active NASA programs or strong contenders for future use. Quantitative and qualitative data has been summarized from recent literature, and in-house information, and presented along with a description of those structures or standards where the information was obtained. Examples, in tabular form, of NDT technique capabilities and limitations have been provided. NDT techniques discussed and assessed were radiography, ultrasonics, penetrants, thermal, acoustic, and electromagnetic. Quantitative data is sparse; therefore, obtaining statistically reliable flaw detection data must be strongly emphasized. The new requirements for reusable space vehicles have resulted in highly efficient design concepts operating in severe environments. This increases the need for quantitative NDT evaluation of selected structural components, the end item structure, and during refurbishment operations.

  19. Quantitative nondestructive characterization of visco-elastic materials at high pressure

    SciTech Connect

    Aizawa, Tatsuhiko; Kihara, Junji; Ohno, Jun

    1995-11-01

    New anvil apparatus was developed to realize high pressure atmosphere suitable to investigation of viscoelastic behaviors of such soft materials as polymers, lubricants, proteins and so forth. In addition, ultrasonic spectroscopy system was also newly constructed to make quantitative nondestructive evaluation of elasticity and viscosity of soft materials at high pressure. In order to demonstrate the validity and effectiveness of the developed system and methodology for quantitative nondestructive visco-elastic characterization, various silicone oils are employed, and measured spectra are compared to the theoretical results calculated by the three linear element model.

  20. Electromagnetic imaging methods for nondestructive evaluation applications.

    PubMed

    Deng, Yiming; Liu, Xin

    2011-01-01

    Electromagnetic nondestructive tests are important and widely used within the field of nondestructive evaluation (NDE). The recent advances in sensing technology, hardware and software development dedicated to imaging and image processing, and material sciences have greatly expanded the application fields, sophisticated the systems design and made the potential of electromagnetic NDE imaging seemingly unlimited. This review provides a comprehensive summary of research works on electromagnetic imaging methods for NDE applications, followed by the summary and discussions on future directions. PMID:22247693

  1. Electromagnetic Imaging Methods for Nondestructive Evaluation Applications

    PubMed Central

    Deng, Yiming; Liu, Xin

    2011-01-01

    Electromagnetic nondestructive tests are important and widely used within the field of nondestructive evaluation (NDE). The recent advances in sensing technology, hardware and software development dedicated to imaging and image processing, and material sciences have greatly expanded the application fields, sophisticated the systems design and made the potential of electromagnetic NDE imaging seemingly unlimited. This review provides a comprehensive summary of research works on electromagnetic imaging methods for NDE applications, followed by the summary and discussions on future directions. PMID:22247693

  2. Nondestructive Evaluation of Aircraft and Spacecraft Wiring

    NASA Technical Reports Server (NTRS)

    White, John E.; Tucholski, Edward J.; Green, Robert E., Jr.

    2004-01-01

    Spacecraft, and especially aircraft, often fry well past their original design lives and, therefore, the need to develop nondestructive evaluation procedures for inspection of vital structures in these craft is extremely important. One of the more recent problems is the degradation of wiring and wiring insulation. The present paper describes several nondestructive characterization methods which afford the possibility to detect wiring and insulation degradation in-situ prior to major problems with the safety of aircraft and spacecraft.

  3. Advancing technologies and applications in nondestructive evaluation

    SciTech Connect

    Logan, C.

    1997-12-01

    The methods used to inspect and evaluate materials, decides, and products are now based on imaging systems that collect digital data and process and interpret them through specially developed computer algorithms. Lawrence Livermore`s Nondestructive and Materials Evaluation Section has been developing a wide range of imaging systems, implementing them through a range of technologies, including digital radiography, computed tomography, machine vision, ultrasonics, and infrared computer thermography. Applications of these various technologies are described in the article. They demonstrate the range and increasing flexibility of the concept of nondestructive evaluation.

  4. NONDESTRUCTIVE EVALUATION (NDE) OF DAMAGED STRUCTURAL CERAMICS

    SciTech Connect

    Brennan, R. E.; Green, W. H.; Sands, J. M.; Yu, J. H.

    2009-03-03

    A combination of destructive and nondestructive testing methods was utilized to evaluate the impact velocity and energy conditions that caused fracture in alumina structural ceramics. Drop tower testing was used for low velocity impact with a high mass indenter and fragment simulating projectile testing was used for high velocity impact with a low mass projectile. The damaged samples were nondestructively evaluated using digital radiography and ultrasound C-scan imaging. The bulk damage detected by these techniques was compared to surface damage observed by visual inspection.

  5. Non-destructive evaluation of composite materials using ultrasound

    NASA Technical Reports Server (NTRS)

    Miller, J. G.

    1984-01-01

    Investigation of the nondestructive evaluation of advanced composite-laminates is summarized. Indices derived from the measurement of fundamental acoustic parameters are used in order to quantitatively estimate the local material properties of the laminate. The following sections describe ongoing studies of phase insensitive attenuation measurements, and discuss several phenomena which influences the previously reported technique of polar backscatter. A simple and effective programmable gate circuit designed for use in estimating attenuation from backscatter is described.

  6. Nondestructive Evaluation of Adhesively Bonded Joints

    NASA Technical Reports Server (NTRS)

    Nayeb-Hashemi, Hamid; Rossettos, J. N.

    1997-01-01

    The final report consists of 5 published papers in referred journals and a technical letter to the technical monitor. These papers include the following: (1) Comparison of the effects of debonds and voids in adhesive; (2) On the peak shear stresses in adhesive joints with voids; (3) Nondestructive evaluation of adhesively bonded joints by acousto-ultrasonic technique and acoustic emission; (4) Multiaxial fatigue life evaluation of tubular adhesively bonded joints; (5) Theoretical and experimental evaluation of the bond strength under peeling loads. The letter outlines the progress of the research. Also included is preliminary information on the study of nondestructive evaluation of composite materials subjected to localized heat damage. The investigators studied the effects of localized heat on unidirectional fiber glass epoxy composite panels. Specimens of the fiber glass epoxy composites were subjected to 400 C heat for varying lengths of time. The specimens were subjected to nondestructive tests. The specimens were then pulled to their failure and acoustic emission of these specimens were measured. The analysis of the data was continuing as of the writing of the letter, and includes a finite element stress analysis of the problem.

  7. Nondestructive evaluation of sintered ceramics

    NASA Technical Reports Server (NTRS)

    Baaklini, George Y.; Klima, Stanley J.; Sanders, William A.

    1988-01-01

    Radiography and several acoustic and thermoacoustic microscopy techniques are investigated for application to structural ceramics for advanced heat engines. A comparison is made of the results obtained from the use of scanning acoustic microscopy (SAM), scanning laser acoustic microscopy (SLAM), and thermoacoustic microscopy (TAM). These techniques are evaluated on research samples of green and sintered monolithic silicon nitrides and silicon carbides in the form of modulus-of-rupture (MOR) bars containing deliberately introduced flaws. Strengths and limitations of the techniques are described, with the emphasis being on statistics of detectability of flaws that constitute potential fracture origins. Further, it is shown that radiographic evaluation and guidance helped develop uniform high-density Si3N4 MOR bars with improved four-point flexural strength (875, 544, and 462 MPa at room temperature, 1200 C, 1370 C, respectively) and reduced scatter in bend strength.

  8. Development of instrumentation for magnetic nondestructive evaluation

    SciTech Connect

    Hariharan, S.

    1991-09-23

    The use of failure-prone components in critical applications has been traditionally governed by removing such components from service prior to the expiration of their predicted life expectancy. Such early retirement of materials does not guarantee that a particular sample will not fail in actual usage. The increasing cost of such life expectancy based operation and increased demand for improved reliability in industrial settings has necessitated an alternate form of quality control. Modern applications employ nondestructive evaluation (NDE), also known as nondestructive testing (NDT), as a means of monitoring the levels and growth of defects in a material throughout its operational life. This thesis describes the modifications made to existing instrumentation used for magnetic measurements at the Center for Nondestructive Evaluation at Iowa State University. Development of a new portable instrument is also given. An overview of the structure and operation of this instrumentation is presented. This thesis discusses the application of the magnetic hysteresis and Barkhausen measurement techniques, described in Sections 1.3.1 and 1.3.2 respectively, to a number of ferromagnetic specimens. Specifically, measurements were made on a number of railroad steel specimens for fatigue characterization, and on specimens of Damascus steel and Terfenol-D for materials evaluation. 60 refs., 51 figs., 5 tabs.

  9. Nondestructive optical methods of food quality evaluation.

    PubMed

    Deshpande, S S; Cheryan, M; Gunasekaran, S; Paulsen, M R; Salunkhe, D K

    1984-01-01

    Quality control is an important aspect of food production and processing from the point of view of providing foods of acceptable nutritional value, and for providing safety of products. Several characteristics such as size, shape, density, maturity, moisture content, oil content, flavor, firmness, tenderness, color, defects, blemishes, etc., are routinely used in the quality control of agricultural and biological food products. Until recently, most analytical techniques used in quality control required isolation of the food component of interest. The original properties of the product are, therefore, destroyed during sample preparation and analysis. Oftentimes, such analyses are expensive, time consuming, and require sophisticated instrumentation, and hence are not suited for "on-line" quality control of food products. Recent progress in the development of instrumentation utilizing the optical properties of food products has provided several nondestructive techniques for quality evaluation. Most optical methods of nondestructive nature make use of the characteristic absorption spectra of components of interest. Such methods are highly sensitive, rapid, and reproducible, and have been successively used in routine "on-line" quality control of a large number of samples. In this article, theoretical considerations in the development of nondestructive analytical techniques based on the optical properties of several agricultural and biological products are briefly reviewed. A major emphasis is placed on quality control methods that are particularly useful in maturity and/or ripeness evaluation of food products, the detection of external and internal defects, and the subsequent development of automatic sorting machines for on-line measurement of quality. PMID:6391826

  10. Instrumental monitoring and nondestructive evaluation of highway bridges

    NASA Astrophysics Data System (ADS)

    Hunt, Victor J.; Turer, Ahmet; Gao, Yong; Levi, Alper; Helmicki, Arthur J.; Barrish, Raymond A., Jr.; Catbas, Fikret N.; Grimmelsman, Kirk A.; Aktan, A. Emin

    1998-03-01

    On-line, continuous monitoring technologies of a rigorous and objective nature are sought to quantitatively identify and evaluate the condition or health of highway structures over their useful lifetime. A global bridge evaluation methodology is under development based upon the structural identification concept, employing modal testing, truckload testing, and instrumented monitoring as its principal experimental tools. Test results are transformed to either modal flexibility or the unit influence line, which have been demonstrated to be conceptual, quantitative, comprehensive, and damage-sensitive signatures. Four test sites were tested, monitored, and studied in order to classify their similar bride-type-specific behavior mechanisms and to validate the performance of the implemented methodology. Practical, type-specific procedures for instrumented monitoring and nondestructive evaluation can then be developed for the whole group or type of highway bridges.

  11. Nondestructive evaluation of thick concrete structures

    NASA Astrophysics Data System (ADS)

    Clayton, Dwight A.

    2015-03-01

    Concrete has been used in the construction of nuclear power plants (NPPs) due to three primary properties: its low cost, structural strength, and ability to shield radiation. Examples of concrete structures important to the safety of Light Water Reactor (LWR) plants include the containment building, spent fuel pool, and cooling towers. Use in these structures has made concrete's long-term performance crucial for the safe operation of commercial NPPs. Extending LWR operating period to 60 years and beyond will likely increase susceptibility and severity of known forms of degradation. New mechanisms of materials degradation are also possible. This creates the need to be able to nondestructively evaluate the current subsurface concrete condition of aging concrete material in NPP structures. The size and complexity of NPP containment structures and heterogeneity of Portland cement concrete make characterization of the degradation extent a difficult task. Specially designed and fabricated test specimens can provide realistic flaws that are similar to actual flaws in terms of how they interact with a particular nondestructive evaluation (NDE) technique. Artificial test blocks allow the isolation of certain testing problems as well as the variation of certain parameters. Representative large heavily reinforced concrete specimens would allow for comparative testing to evaluate the state-of-the-art NDE in this area and to identify additional developments necessary to address the challenges potentially found in NPPs.

  12. Nondestructive Evaluation of Nuclear-Grade Graphite

    SciTech Connect

    Dennis C. Kunerth; Timothy R. McJunkin

    2011-07-01

    Nondestructive Evaluation of Nuclear Grade Graphite Dennis C. Kunerth and Timothy R. McJunkin Idaho National Laboratory Idaho Falls, ID, 83415 This paper discusses the nondestructive evaluation of nuclear grade graphite performed at the Idaho National Laboratory. Graphite is a composite material highly dependent on the base material and manufacturing methods. As a result, material variations are expected within individual billets as well billet to billet and lot to lot. Several methods of evaluating the material have been explored. Particular technologies each provide a subset of information about the material. This paper focuses on techniques that are applicable to in-service inspection of nuclear energy plant components. Eddy current examination of the available surfaces provides information on potential near surface structural defects and although limited, ultrasonics can be utilized in conventional volumetric inspection. Material condition (e.g. micro-cracking and porosity induced by radiation and stress) can be derived from backscatter or acousto-ultrasound (AU) methods. Novel approaches utilizing phased array ultrasonics have been attempted to expand the abilities of AU techniques. By combining variable placement of apertures, angle and depth of focus, the techniques provide the potential to obtain parameters at various depths in the material. Initial results of the study and possible procedures for application of the techniques are discussed.

  13. Complementary Electromagnetic Non-Destructive Evaluation

    NASA Astrophysics Data System (ADS)

    Tian, Gui Yun; Wilson, John; Morozov, Maxim

    2011-06-01

    The use of non-destructive evaluation (NDE) for defect detection and failure prediction in structures and specimens is widespread in energy industries, aimed at ageing power plants and pipelines, material degradation, fatigue and radiation damage, etc. At present there are no suitable electromagnetic NDE methods for the measurement and characterization of material degradation, in irradiated samples in particular, which is very important and timely for the nuclear power industry in the UK. This paper reports recent developments in the field of electromagnetic (EM) NDE at Newcastle University, including pulsed eddy current (PEC), pulsed magnetic flux leakage (PMFL), magnetic Barkhausen emission (MBE) and magneto-acoustic emission (MAE). As different EM methods have different strengths, an integrative EM framework is introduced. Case studies through the second round robin tests organized by the Universal Network for Magnetic Non-Destructive Evaluation (UNMNDE), representing eighteen leading research groups worldwide in the area of electromagnetic NDE, are reported. Twelve samples with different ageing times and rolling reduction ratios were tested using different magnetic methods among the UNMNDE members. Based on the studies, the complementary characteristics of electromagnetic techniques for NDE are discussed.

  14. NONDESTRUCTIVE EVALUATION OF CERAMIC CANDLE FILTERS

    SciTech Connect

    Roger H.L. Chen, Ph.D.; Alejandro Kiriakidis

    1999-09-01

    Nondestructive evaluation (NDE) techniques have been used to reduce the potential mechanical failures and to improve the reliability of a structure. Failure of a structure is usually initiated at some type of flaw in the material. NDE techniques have been developed to determine the presence of flaws larger than an acceptable size and to estimate the remaining stiffness of a damaged structure (Chen, et. al, 1995). Ceramic candle filters have been tested for use in coal-fueled gas turbine systems. They protect gas turbine components from damage due to erosion. A total of one hundred and one candle filters were nondestructively evaluated in this study. Ninety-eight ceramic candle filters and three ceramic composite filters have been nondestructively inspected using dynamic characterization technique. These ceramic filters include twelve unused Coors alumina/mullite, twenty-four unused and fifteen used Schumacher-Dia-Schumalith TF-20, twenty-five unused and nine used Refractron 326, eight unused and three used Refractron 442T, one new Schumacher-T 10-20, and one used Schumacher-Dia-Schumalith F-40. All filters were subjected to a small excitation and the dynamic response was picked up by a piezoelectric accelerometer. The evaluation of experimental results was processed using digital signal analysis technique including various forms of data transformation. The modal parameters for damage assessment for the unexposed (unused) vs. exposed (used) specimen were based on two vibration parameters: natural frequencies and mode shapes. Finite Element models were built for each specimen type to understand its dynamic response. Linear elastic modal analysis was performed using eight nodes, three-dimensional isotropic solid elements. Conclusions based on our study indicate that dynamic characterization is a feasible NDE technique in studying structural properties of ceramic candle filters. It has been shown that the degradation of the filters due to long working hours (or excessive back pulsing conditions and high temperature transient) could be reflected from the shift of vibration frequencies. These shifts are due to changes in structural properties such as stiffness, which are directly related to the Young's modulus of the candle filters. Further studies are necessary in implementing and verifying the applicability of dynamic NDE characterization methods for actual in-situ conditions, and in establishing a systematic testing procedure for field applications. Also investigations on the filter's natural frequency due to the effect of dust cake or due to the change of boundary conditions may provide insight as to how the filter will perform in the field.

  15. Non-destructive evaluation of composites

    NASA Technical Reports Server (NTRS)

    Chu, Tsuchin Philip

    1996-01-01

    The composite materials have been used in aerospace industries for quite some time. Several non-destructive evaluation (NDE) methods have been developed to inspect composites in order to detect flaws, matrix cracking, and delamination. These methods include ultrasonics, acoustic emission, shearography, thermography, X-ray, and digital image correlation. The NDE Branch of Marshall Space Flight Center has recently acquired a thermal imaging NDE system. The same system has been used at NASA Langley Research Center for detecting disbonds. In order to compare different NDE methods, three carbon/carbon composite panels were used for experiment using ultrasonic C-scan, shearography, and thermography methods. These panels have teflon inserts to simulate the delamination between plies in a composite panel. All three methods have successfully located the insert. The experiment and results are presented in the following sections.

  16. Nondestructive Evaluation of Trunnion Bearing Pins

    NASA Astrophysics Data System (ADS)

    Story, B.; Fry, G. T.; Hurlebaus, S.

    2010-02-01

    Currently, there are several issues plaguing the bridge infrastructure in the United States. These structures are aging and reaching the end of their original design life while simultaneously experiencing increases in train speed, axle load, and train length. As a result of reaching the end of their original design lives, special attention must be given to evaluate the effects of deterioration such as corrosion and fatigue. This research project investigates the integrity of trunnion bearing pins using ultrasonic techniques that (1) minimize disassembling of the bearing, (2) minimize the lock time of the bridge, and (3) are nondestructive. The proposed technique uses an ultrasonic probe to inspect the bearing pin from the center hole as well as an ultrasonic transducer to inspect the pins from their faces. The results of this project show that the proposed method is capable of detecting discontinuities in the bearing pin such as the keyholes.

  17. Preliminary nondestructive evaluation manual for the space shuttle. [preliminary nondestructive evaluation

    NASA Technical Reports Server (NTRS)

    Pless, W. M.

    1974-01-01

    Nondestructive evaluation (NDE) requirements are presented for some 134 potential fracture-critical structural areas identified, for the entire space shuttle vehicle system, as those possibly needing inspection during refurbishment/turnaround and prelaunch operations. The requirements include critical area and defect descriptions, access factors, recommended NDE techniques, and descriptive artwork. Requirements discussed include: Orbiter structure, external tank, solid rocket booster, and thermal protection system (development area).

  18. Nondestructive evaluation development for process control

    SciTech Connect

    Ellingson, W.A.; Holloway, D.L.; Sivers, E.A. ); Ling, J. . Inst. for Ceramics); Pollinger, J.P.; Yeh, H.C. . Garrett Ceramic Components Div.)

    1991-01-01

    A joint project between Garrett Ceramic Components (GCC) of Allied Signal Aerospace Corporation and Argonne National Laboratory (ANL) is ongoing to evaluate nondestructive characterization (NDC) methods to detect and measure process-induced variations in ceramic materials. The process methods of current focus on slip-casting and injection molding and the NDC methods being evaluated are microfocus X-ray computed tomography (XCT) and nuclear magnetic resonance computed tomography (MRCT). As part of this work, SiC whisker reinforced Si{sub 3}N{sub 4} (GCC's GN-10 material) has been pressure slip-cast at two casting pressures, 15 and 40 psi; and at length/diameter ratios of 1.5, 2.5 and 3.0 with whisker contents of 20, 23, 27 and 30 wt %. Three-dimensional microfocus XCT has been used to study density variations in billets produced by different process conditions. Destructive measurement of density variation has been compared to the XCT measurements and correlations established. XCT has been shown to be able to detect <5% variations in as-cast density and these were destructively verified.

  19. Nondestructive evaluation development for process control

    SciTech Connect

    Ellingson, W.A.; Holloway, D.L.; Sivers, E.A.; Ling, J.; Pollinger, J.P.; Yeh, H.C.

    1991-12-31

    A joint project between Garrett Ceramic Components (GCC) of Allied Signal Aerospace Corporation and Argonne National Laboratory (ANL) is ongoing to evaluate nondestructive characterization (NDC) methods to detect and measure process-induced variations in ceramic materials. The process methods of current focus on slip-casting and injection molding and the NDC methods being evaluated are microfocus X-ray computed tomography (XCT) and nuclear magnetic resonance computed tomography (MRCT). As part of this work, SiC whisker reinforced Si{sub 3}N{sub 4} (GCC`s GN-10 material) has been pressure slip-cast at two casting pressures, 15 and 40 psi; and at length/diameter ratios of 1.5, 2.5 and 3.0 with whisker contents of 20, 23, 27 and 30 wt %. Three-dimensional microfocus XCT has been used to study density variations in billets produced by different process conditions. Destructive measurement of density variation has been compared to the XCT measurements and correlations established. XCT has been shown to be able to detect <5% variations in as-cast density and these were destructively verified.

  20. Nondestructive Evaluation of Reactive Powder Concrete

    NASA Astrophysics Data System (ADS)

    Washer, Glenn; Fuchs, Paul; Graybeal, Benjamin; Rezaizadeh, Ali

    2004-02-01

    Reactive powder concrete (RPC) has been introduced as a structural material for civil engineering applications. The material consists of a finely graded combination of cement, sand, ground quartz and silica fume which combined with water form a cement paste. Small steel fibers measuring approximately 0.2 mm in diameter and 12 mm in length are distributed throughout the cement matrix and the combined material has very high compressive strength and toughness. The material is proposed for use in the primary load bearing members in bridges, and as such nondestructive evaluation technologies are needed to evaluate material quality and monitor in-service condition. This paper reports on research to determine the effectiveness of ultrasonic testing for determining the elastic properties of RPC. Comparison between static modulus of elasticity and ultrasonic modulus measurements is presented. A system for determining elastic moduli as a quality control tool is discussed. The effect of curing conditions on ultrasonic velocities and resulting calculated moduli values is presented and compared with traditional measurement methods.

  1. Nondestructive tests of regenerative chambers. [evaluating nondestructive methods of determining metal bond integrity

    NASA Technical Reports Server (NTRS)

    Malone, G. A.; Vecchies, L.; Wood, R.

    1974-01-01

    The capabilities and limitations of nondestructive evaluation methods were studied to detect and locate bond deficiencies in regeneratively cooled thrust chambers for rocket engines. Flat test panels and a cylinder were produced to simulate regeneratively cooled thrust chamber walls. Planned defects with various bond integrities were produced in the panels to evaluate the sensitivity, accuracy, and limitations of nondestructive methods to define and locate bond anomalies. Holography, acoustic emission, and ultrasonic scan were found to yield sufficient data to discern bond quality when used in combination and in selected sequences. Bonding techniques included electroforming and brazing. Materials of construction included electroformed nickel bonded to Nickel 200 and OFHC copper, electroformed copper bonded to OFHC copper, and 300 series stainless steel brazed to OFHC copper. Variations in outer wall strength, wall thickness, and defect size were evaluated for nondestructive test response.

  2. Nondestructive Evaluation Correlated with Finite Element Analysis

    NASA Technical Reports Server (NTRS)

    Abdul-Azid, Ali; Baaklini, George Y.

    1999-01-01

    Advanced materials are being developed for use in high-temperature gas turbine applications. For these new materials to be fully utilized, their deformation properties, their nondestructive evaluation (NDE) quality and material durability, and their creep and fatigue fracture characteristics need to be determined by suitable experiments. The experimental findings must be analyzed, characterized, modeled and translated into constitutive equations for stress analysis and life prediction. Only when these ingredients - together with the appropriate computational tools - are available, can durability analysis be performed in the design stage, long before the component is built. One of the many structural components being evaluated by the NDE group at the NASA Lewis Research Center is the flywheel system. It is being considered as an energy storage device for advanced space vehicles. Such devices offer advantages over electrochemical batteries in situations demanding high power delivery and high energy storage per unit weight. In addition, flywheels have potentially higher efficiency and longer lifetimes with proper motor-generator and rotor design. Flywheels made of fiber-reinforced polymer composite material show great promise for energy applications because of the high energy and power densities that they can achieve along with a burst failure mode that is relatively benign in comparison to those of flywheels made of metallic materials Therefore, to help improve durability and reduce structural uncertainties, we are developing a comprehensive analytical approach to predict the reliability and life of these components under these harsh loading conditions. The combination of NDE and two- and three-dimensional finite element analyses (e.g., stress analyses and fracture mechanics) is expected to set a standardized procedure to accurately assess the applicability of using various composite materials to design a suitable rotor/flywheel assembly.

  3. Nondestructive evaluation of composite materials - A design philosophy

    NASA Technical Reports Server (NTRS)

    Duke, J. C., Jr.; Henneke, E. G., II; Stinchcomb, W. W.; Reifsnider, K. L.

    1984-01-01

    Efficient and reliable structural design utilizing fiber reinforced composite materials may only be accomplished if the materials used may be nondestructively evaluated. There are two major reasons for this requirement: (1) composite materials are formed at the time the structure is fabricated and (2) at practical strain levels damage, changes in the condition of the material, that influence the structure's mechanical performance is present. The fundamental basis of such a nondestructive evaluation capability is presented. A discussion of means of assessing nondestructively the material condition as well as a damage mechanics theory that interprets the material condition in terms of its influence on the mechanical response, stiffness, strength and life is provided.

  4. Cryogenic Storage Tank Non-Destructive Evaluation

    NASA Technical Reports Server (NTRS)

    Arens, Ellen

    2010-01-01

    This slide presentation reviews the work in non-destructive evaluation (NDE) of cryogenic storage tanks. Four large cryogenic tanks, constructed in 1965 with perlite insulation in the annular regions, are of concern. The construction of the tanks, two Liquid Oxygen (LOX) and two Liquid Hydrogen (LH2), are described. The loss rate for the LOX tank at Pad A is slightly higher than that for the one at Pad B. The concerns for the LH2 tank at Pad B are that there is a significantly higher boil-off rate than that at Pad A, that there is mold growth, indicative of increased heat flow, that there is a long down-time needed for repairs, and that 3 of 5 full thermal cycles have been used on the Pad B LH2 tank. The advantages and disadvantages of thermal imaging are given. A detailed description of what is visible of the structures in the infra-red is given and views of the thermal images are included. Missing Perlite is given as the probable cause of the cold spot on the Pad B LH2 tank. There is no indications of problematic cold regions on the Pad A LH2 tank, as shown by the thermal images given in the presentation. There is definite indication of a cold region on the Pad A LOX tank. There is however concerns with thermal imaging, as thermal images can be significantly effected by environmental conditions, image differences on similar days but with different wind speeds. Other effects that must be considered include ambient temperature, humidity levels/dew, and cloud reflections

  5. Guided wave nuances for ultrasonic nondestructive evaluation.

    PubMed

    Rose, J L

    2000-01-01

    Recent developments in guided wave generation, reception, and mode control show that increased penetration power and sensitivity are possible. A tone burst function generator and appropriate signal processing are generally used. Variable angle beam and comb-type transducers are the key to this effort. Problems in tubing, piping, hidden corrosion detection in aging aircraft, adhesive and diffusion bonding, and ice detection are discussed. Additionally, sample configurations, inspection objectives, and logic are being developed for such sample problems as defect detection and analysis in lap splice joints, tear straps, cracks in a second layer, hidden corrosion in multiple layers, cracks from rivet holes, transverse cracking in a beam, and cracks in landing gear assembly. Theoretical and experimental aspects of guided wave analysis include phase velocity, group velocity, and attenuation dispersion curves; boundary element model analysis for reflection and transmission factor analysis; use of wave structure for defect detection sensitivity; source influence on the phase velocity spectrum, and the use of angle beam and comb transducer technology. Probe design and modeling considerations are being explored. Utilization of in-plane and out-of-plane displacement patterns on the surface and longitudinal power distribution across the structural cross-section are considered for improved sensitivity, penetration power, and resolution in nondestructive evaluation. Methods of controlling the phase velocity spectrum for mode and frequency selection are available. Such features as group velocity change, mode cut-off measurements, mode conversion, amplitude ratios of transmission, and reflection factors of specific mode and frequency as input will be introduced for their ability to be used in flaw and material characterization analysis. PMID:18238584

  6. Quantitative impact characterization of aeronautical CFRP materials with non-destructive testing methods

    SciTech Connect

    Kiefel, Denis E-mail: Rainer.Stoessel@airbus.com; Stoessel, Rainer E-mail: Rainer.Stoessel@airbus.com; Grosse, Christian

    2015-03-31

    In recent years, an increasing number of safety-relevant structures are designed and manufactured from carbon fiber reinforced polymers (CFRP) in order to reduce weight of airplanes by taking the advantage of their specific strength into account. Non-destructive testing (NDT) methods for quantitative defect analysis of damages are liquid- or air-coupled ultrasonic testing (UT), phased array ultrasonic techniques, and active thermography (IR). The advantage of these testing methods is the applicability on large areas. However, their quantitative information is often limited on impact localization and size. In addition to these techniques, Airbus Group Innovations operates a micro x-ray computed tomography (μ-XCT) system, which was developed for CFRP characterization. It is an open system which allows different kinds of acquisition, reconstruction, and data evaluation. One main advantage of this μ-XCT system is its high resolution with 3-dimensional analysis and visualization opportunities, which enables to gain important quantitative information for composite part design and stress analysis. Within this study, different NDT methods will be compared at CFRP samples with specified artificial impact damages. The results can be used to select the most suitable NDT-method for specific application cases. Furthermore, novel evaluation and visualization methods for impact analyzes are developed and will be presented.

  7. Quantitative impact characterization of aeronautical CFRP materials with non-destructive testing methods

    NASA Astrophysics Data System (ADS)

    Kiefel, Denis; Stoessel, Rainer; Grosse, Christian

    2015-03-01

    In recent years, an increasing number of safety-relevant structures are designed and manufactured from carbon fiber reinforced polymers (CFRP) in order to reduce weight of airplanes by taking the advantage of their specific strength into account. Non-destructive testing (NDT) methods for quantitative defect analysis of damages are liquid- or air-coupled ultrasonic testing (UT), phased array ultrasonic techniques, and active thermography (IR). The advantage of these testing methods is the applicability on large areas. However, their quantitative information is often limited on impact localization and size. In addition to these techniques, Airbus Group Innovations operates a micro x-ray computed tomography (μ-XCT) system, which was developed for CFRP characterization. It is an open system which allows different kinds of acquisition, reconstruction, and data evaluation. One main advantage of this μ-XCT system is its high resolution with 3-dimensional analysis and visualization opportunities, which enables to gain important quantitative information for composite part design and stress analysis. Within this study, different NDT methods will be compared at CFRP samples with specified artificial impact damages. The results can be used to select the most suitable NDT-method for specific application cases. Furthermore, novel evaluation and visualization methods for impact analyzes are developed and will be presented.

  8. Nondestructive Evaluation of Metal Fatigue Using Nonlinear Acoustics

    NASA Technical Reports Server (NTRS)

    Cantrell, John H., Jr.

    2008-01-01

    Safe-life and damage-tolerant design philosophies of high performance structures have driven the development of various methods to evaluate nondestructively the accumulation of damage in such structures resulting from cyclic loading. Although many techniques have proven useful, none has been able to provide an unambiguous, quantitative assessment of damage accumulation at each stage of fatigue from the virgin state to fracture. A method based on nonlinear acoustics is shown to provide such a means to assess the state of metal fatigue. The salient features of an analytical model are presented of the microelastic-plastic nonlinearities resulting from the interaction of an acoustic wave with fatigue-generated dislocation substructures and cracks that predictably evolve during the metal fatigue process. The interaction is quantified by the material (acoustic) nonlinearity parameter extracted from acoustic harmonic generation measurements. The parameters typically increase monotonically by several hundred percent over the fatigue life of the metal, thus providing a unique measure of the state of fatigue. Application of the model to aluminum alloy 2024-T4, 410Cb stainless steel, and IN100 nickel-base superalloy specimens fatigued using different loading conditions yields good agreement between theory and experiment. Application of the model and measurement technique to the on-site inspection of steam turbine blades is discussed.

  9. Nondestructive evaluation of compacted clayey soils

    NASA Astrophysics Data System (ADS)

    Inci, Gokhan

    Compacted clayey soils are analyzed using nondestructive testing methods. Ultrasonic testing and image analysis are used as nondestructive testing techniques. Tests were conducted on three clayey soils with low to high plasticities. The soils are compacted and then allowed to dry or subjected to wetting and drying cycles subsequent to compaction. Ultrasonic tests are performed to determine small strain elastic properties of soils during drying. Image analysis techniques are used to determine large strains and cracking behavior of soils during wetting and drying cycles. Finally, numerical methods are used to simulate large and small strain soil behavior. Ultrasonic testing can be used effectively to determine compaction characteristics of soils. Through transmission can be applicable in the laboratory or on recovered field samples while surface transmission can be used in the field. Variation of P-wave velocity is similar to variation of dry density for the test soils. Increasing compactive effort cause increases in measured wave velocity. Variations of elastic parameters during drying are investigated. More variation was observed for soils compacted with low compaction effort and high water contents. Five elastic parameters of cross-anisotropy are calculated from wave velocity measurements on cubical samples with oblique cuts. Constrained, Young's, and shear moduli increase, while Poisson's ratios decrease during drying. Starting with isotropy assumption, empirical formulas are used to calculate the shear moduli and results are compared with experimental shear modulus values obtained using the theory of elasticity. A new formulation is developed to compute shear modulus variation with saturation. Behavior of compacted clayey soils during wetting and drying was also investigated. High plasticity-fine grained soils tend to shrink and crack more during drying. Cracks of these soils tend to heal and close during wetting cycles. Cracking and healing are less for medium and low plasticity soils. Cracking is observed at relatively low suction levels for all soil types. Cracking is quantified using image analysis techniques. Finite element models are successfully used to make predictions on small strainwave propagation and fracture potential of soils. Transducer size has significant effect on surface arrangement arrival times and water content profile has significant effect on fracture potential.

  10. Airborne Ultrasonics for Nondestructive Evaluation of Leather Quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our recent research has shown that besides Acoustic Emission (AE), Airborne Ultrasonics (AU) can also be applied for the nondestructive evaluation (NDE) of leather quality. Implementation of these methods in the manufacturing process could save a considerable amount of money, decrease the use of ch...

  11. Quantitative non-destructive characterisation (NDC) of plant fibre composites

    NASA Astrophysics Data System (ADS)

    Rheinländer, Jørgen; Cendre, Emmanuelle; Debel, Christian; Borum, Kaj K.; Lilholt, Hans

    1999-12-01

    Composites made of plant fibres offer a new, environmentally attractive supplement to traditional glass fibre composite materials. Plant fibre composites may have similar mechanical properties as conventional (e.g. glass fibre) composites, with a lower impact strength. Since plant fibre composites constitute a relatively new group of materials, the limitations imposed on the mechanical performance due to flaws are not well known. The subject of this article is the investigation of the structure, the homogeneity and the mechanical properties of jute fibre based composites, and the correlation to quantitative data derived from X-radiography and ultrasonic scanning. The results indicates that parameters such as fibre orientation and fibre volume fraction are very important concerning sample tensile strength. These parameters can be assessed by the considered QNDC techniques. It is also shown that the samples are relatively homogeneous, and that the limitation on mechanical performance cannot by the considered techniques be related to a single defect. From the results it may be further concluded that the NDC techniques can provide quantitative data for an assessment of important manufacturing variables.

  12. Quantitative electromechanical impedance method for nondestructive testing based on a piezoelectric bimorph cantilever

    NASA Astrophysics Data System (ADS)

    Fu, Ji; Tan, Chi; Li, Faxin

    2015-06-01

    The electromechanical impedance (EMI) method, which holds great promise in structural health monitoring (SHM), is usually treated as a qualitative method. In this work, we proposed a quantitative EMI method based on a piezoelectric bimorph cantilever using the sample’s local contact stiffness (LCS) as the identification parameter for nondestructive testing (NDT). Firstly, the equivalent circuit of the contact vibration system was established and the analytical relationship between the cantilever’s contact resonance frequency and the LCS was obtained. As the LCS is sensitive to typical defects such as voids and delamination, the proposed EMI method can then be used for NDT. To verify the equivalent circuit model, two piezoelectric bimorph cantilevers were fabricated and their free resonance frequencies were measured and compared with theoretical predictions. It was found that the stiff cantilever’s EMI can be well predicted by the equivalent circuit model while the soft cantilever’s cannot. Then, both cantilevers were assembled into a homemade NDT system using a three-axis motorized stage for LCS scanning. Testing results on a specimen with a prefabricated defect showed that the defect could be clearly reproduced in the LCS image, indicating the validity of the quantitative EMI method for NDT. It was found that the single-frequency mode of the EMI method can also be used for NDT, which is faster but not quantitative. Finally, several issues relating to the practical application of the NDT method were discussed. The proposed EMI-based NDT method offers a simple and rapid solution for damage evaluation in engineering structures and may also shed some light on EMI-based SHM.

  13. Hyperspectral imaging for nondestructive evaluation of tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Machine vision methods for quality and defect evaluation of tomatoes have been studied for online sorting and robotic harvesting applications. We investigated the use of a hyperspectral imaging system for quality evaluation and defect detection for tomatoes. Hyperspectral reflectance images were a...

  14. Materials and Nondestructive Evaluation Laboratoriers: User Test Planning Guide

    NASA Technical Reports Server (NTRS)

    Schaschl, Leslie

    2011-01-01

    The Materials and Nondestructive Evaluation Laboratory process, milestones and inputs are unknowns to first-time users. The Materials and Nondestructive Evaluation Laboratory Planning Guide aids in establishing expectations for both NASA and non- NASA facility customers. The potential audience for this guide includes both internal and commercial spaceflight hardware developers. It is intended to assist their project engineering personnel in materials analysis planning and execution. Material covered includes a roadmap of the analysis process, roles and responsibilities of facility and user, major milestones, facility capabilities, and inputs required by the facility. Samples of deliverables, products, and inputs necessary to define scope of analysis, cost, and schedule are included as an appendix to the guide.

  15. The use of infrared thermography for nondestructive evaluation of joints

    NASA Astrophysics Data System (ADS)

    Meola, Carosena; Carlomagno, Giovanni M.; Squillace, Antonino; Giorleo, Giuseppe

    2004-12-01

    A junction between two similar, or dissimilar, materials represents generally a weak structural point and so it requires accurate choice of the most adequate joining technique and nondestructive evaluation of joined parts whatever the joining technique. The attention of the present paper is focused on the aid provided by infrared thermography for nondestructive evaluation of three types of joints: aluminum adhesively bonded joints, stainless steel laser welded joints and Glare ® mechanical fastened joints. Both techniques, pulse and modulated thermography with optical stimulation, are used. The attention is particularly focused on the second method because phase images are practically not affected by local nonuniform heating and/or local variation of the emissivity coefficient as thermal images.

  16. Nondestructive evaluation of critical composite material structural elements

    NASA Astrophysics Data System (ADS)

    Duke, John C., Jr.; Lesko, John J.; Weyers, R.

    1996-11-01

    A small span bridge that has suffered corrosive deterioration of a number of the steel structural members is in the process of being rehabilitated with glass and carbon fiber reinforced, pultruded polymer structural beams. As part of a comprehensive research program to develop methods for modeling long term durability of the composite material, nondestructive evaluation if being used to provide a preliminary assessment of the initial condition of the beams as well as to monitor the deterioration of the beams during service.

  17. Nondestructive Evaluation of Ceramic Candle Filters Using Vibration Response

    SciTech Connect

    Chen, Roger H. L.; Kiriakidis, Alejandro C.; Peng, Steve W.

    1997-07-01

    This study aims at the development of an effective nondestructive evaluation technique to predict the remaining useful life of a ceramic candle filter during a power plant's annual maintenance shutdown. The objective of the present on-going study is to establish the vibration signatures of ceramic candle filters at varying degradation levels due to different operating hours, and to study the various factors involving the establishment of the signatures.

  18. Nondestructive Evaluation of the VSC-17 Cask

    SciTech Connect

    Sheryl Morton; Al Carlson; Cecilia Hoffman; James Rivera; Phil Winston; Koji Shirai; Shin Takahashi; Masaharo Tanaka

    2006-01-01

    In 2003, representatives from the Central Research Institute of Electric Power Industry (CRIEPI) requested development of a project with the objective of determining the performance of a concrete spent nuclear fuel storage cask. Radiation and environmental effects may cause chemical alteration of the concrete that could result in excessive cracking, spalling, and loss of compressive strength. The Idaho National Laboratory (INL) project team and CRIEPI representatives identified the Ventilated Storage Cask (VSC 17) spent nuclear fuel storage cask, originally located at the INL Test Area North, as a candidate to study cask performance because it had been used to store fuel as part of a dry cask storage demonstration project for over 15 years. The project involved investigating the properties of the concrete shield. INL performed a survey of the cask in the summers of 2003 and 2004. The INL team met with the CRIEPI representatives in December of 2004 to discuss the next steps. As a result of that meeting, CRIEPI requested that in the summer 2005 INL perform additional surveys on the VSC 17 cask with participation of CRIEPI scientists. This document summarizes the evaluation methods used on the VSC 17 to evaluate the cask for compressive strength, concrete cracking, concrete thickness, and temperature distribution.

  19. Overview of vibrational-based nondestructive evaluation techniques

    NASA Astrophysics Data System (ADS)

    Shen, Ji Yao; Sharpe, Lonnie, Jr.; Jankovsky, Amy L.

    1998-03-01

    Non-destructive damage detection is an important issue in almost all structural areas ranging from aerospace/aeronautical structures, civil infrastructures, and structural materials. The use of vibrational-based nondestructive evaluation techniques to locate structural damage has been attempted to evaluate the integrity of civil infrastructures, composite laminates, continuum structures, and especially aircraft and large space structures. In an attempt to develop a structural health monitoring system for rocket engines, hundreds of technical papers in the vibrational assessment area have been reviewed. This paper provides a comprehensive overview of various vibrational- based nondestructive evaluation techniques, including a brief introduction of the theoretical background of different methods, an analysis of their advantages and drawbacks, and a foresight of the applications of different methods towards different type of structures. To date most research into vibrational-based structural damage detection has been performed by a handful of researchers at a wide variety of sites with little or no coordination in research efforts. Many of these methods have been tested using mass- spring test models or simple planar truss models. Few of standard test problems truly embrace the essence of real- world structures and as such poor judges of the performance of a few method. There clearly is a gap between theoretical research and practical application. This paper would be considerably helpful for future research, and especially beneficial for the development of a structural monitoring system in choosing an applicable and realistic method as a basis.

  20. A versatile nondestructive evaluation imaging workstation

    NASA Technical Reports Server (NTRS)

    Chern, E. James; Butler, David W.

    1994-01-01

    Ultrasonic C-scan and eddy current imaging systems are of the pointwise type evaluation systems that rely on a mechanical scanner to physically maneuver a probe relative to the specimen point by point in order to acquire data and generate images. Since the ultrasonic C-scan and eddy current imaging systems are based on the same mechanical scanning mechanisms, the two systems can be combined using the same PC platform with a common mechanical manipulation subsystem and integrated data acquisition software. Based on this concept, we have developed an IBM PC-based combined ultrasonic C-scan and eddy current imaging system. The system is modularized and provides capacity for future hardware and software expansions. Advantages associated with the combined system are: (1) eliminated duplication of the computer and mechanical hardware, (2) unified data acquisition, processing and storage software, (3) reduced setup time for repetitious ultrasonic and eddy current scans, and (4) improved system efficiency. The concept can be adapted to many engineering systems by integrating related PC-based instruments into one multipurpose workstation such as dispensing, machining, packaging, sorting, and other industrial applications.

  1. Nondestructive inspection and evaluation of composite-material flywheels

    SciTech Connect

    Boyd, D M; Maxfield, B W; Kulkarni, S V; Schwarber, A J

    1982-02-24

    Several composite panels and flywheel designs were evaluated in support of the Mechanical Energy Storage Technology (MEST) project. Conventional nondestructive evaluation (NDE) technology was used on the panels and flywheels. All flywheels and panels were radiographed and, where practical, were also inspected using ultrasonic techniques. The results provided information about the structural features of flywheels and materials. This information is useful for the quality control of fabrication procedures. The detection of apparent flaws in fabrication cannot be related to the ultimate strength until failure mechanisms in composite materials have been fully defined. Therefore, the location of detected flaws should be recorded for later comparison with dynamic and destructive evaluations.

  2. Nondestructive damage evaluation in ceramic matrix composites for aerospace applications.

    PubMed

    Dassios, Konstantinos G; Kordatos, Evangelos Z; Aggelis, Dimitrios G; Matikas, Theodore E

    2013-01-01

    Infrared thermography (IRT) and acoustic emission (AE) are the two major nondestructive methodologies for evaluating damage in ceramic matrix composites (CMCs) for aerospace applications. The two techniques are applied herein to assess and monitor damage formation and evolution in a SiC-fiber reinforced CMC loaded under cyclic and fatigue loading. The paper explains how IRT and AE can be used for the assessment of the material's performance under fatigue. IRT and AE parameters are specifically used for the characterization of the complex damage mechanisms that occur during CMC fracture, and they enable the identification of the micromechanical processes that control material failure, mainly crack formation and propagation. Additionally, these nondestructive parameters help in early prediction of the residual life of the material and in establishing the fatigue limit of materials rapidly and accurately. PMID:23935428

  3. Nondestructive Damage Evaluation in Ceramic Matrix Composites for Aerospace Applications

    PubMed Central

    Dassios, Konstantinos G.; Kordatos, Evangelos Z.; Aggelis, Dimitrios G.; Matikas, Theodore E.

    2013-01-01

    Infrared thermography (IRT) and acoustic emission (AE) are the two major nondestructive methodologies for evaluating damage in ceramic matrix composites (CMCs) for aerospace applications. The two techniques are applied herein to assess and monitor damage formation and evolution in a SiC-fiber reinforced CMC loaded under cyclic and fatigue loading. The paper explains how IRT and AE can be used for the assessment of the material's performance under fatigue. IRT and AE parameters are specifically used for the characterization of the complex damage mechanisms that occur during CMC fracture, and they enable the identification of the micromechanical processes that control material failure, mainly crack formation and propagation. Additionally, these nondestructive parameters help in early prediction of the residual life of the material and in establishing the fatigue limit of materials rapidly and accurately. PMID:23935428

  4. Evaluation of an electric field sensor for nondestructive material inspection

    NASA Astrophysics Data System (ADS)

    Kalyanasundaram, Kayatri; Arunachalam, Kavitha

    2013-01-01

    An electric field sensor is fabricated on a 125 micron thick flexible dielectric substrate for electromagnetic (EM) nondestructive material inspection at 915 MHz. The sensor consists of an electrically short dipole antenna and a radio frequency (RF) diode detector connected to a pair of high impedance screen printed carbon lines. The DC component of the rectified diode voltage conveyed across the high impedance lines is measured using a data acquisition circuit. Sensor measurements are validated with simulated data for a conformal patch antenna operating at 915 MHz. Sensor performance for EM nondestructive testing (NDT) is evaluated using phantom defects in low loss dielectric slabs. Preliminary results indicate sensor utility for EM NDT and support further testing on realistic defects.

  5. Evaluation of Nondestructive Assay/Nondestructive Examination Capabilities for Department of Energy Spent Nuclear Fuel

    SciTech Connect

    Luptak, A.J.; Bulmahn, K.D.

    1998-09-01

    This report summarizes an evaluation of the potential use of nondestructive assay (NDA) and nondestructive examination (NDE) technologies on DOE spent nuclear fuel (SNF). It presents the NDA/NDE information necessary for the National Spent Nuclear Fuel Program (NSNFP) and the SNF storage sites to use when defining that role, if any, of NDA/NDE in characterization and certification processes. Note that the potential role for NDA/NDE includes confirmatory testing on a sampling basis and is not restricted to use as a primary, item-specific, data collection method. The evaluation does not attempt to serve as a basis for selecting systems for development or deployment. Information was collected on 27 systems being developed at eight DOE locations. The systems considered are developed to some degree, but are not ready for deployment on the full range of DOE SNF and still require additional development. The system development may only involve demonstrating performance on additional SNF, packaging the system for deployment, and developing calibration standards, or it may be as extensive as performing additional basic research. Development time is considered to range from one to four years. We conclude that NDA/NDE systems are capable of playing a key role in the characterization and certification of DOE SNF, either as the primary data source or as a confirmatory test. NDA/NDE systems will be able to measure seven of the nine key SNF properties and to derive data for the two key properties not measured directly. The anticipated performance goals of these key properties are considered achievable except for enrichment measurements on fuels near 20% enrichment. NDA/NDE systems can likely be developed to measure the standard canisters now being considered for co-disposal of DOE SNF. This ability would allow the preparation of DOE SNF for storage now and the characterization and certification to be finalize later.

  6. Efficient Nondestructive Evaluation of Prototype Carbon Fiber Reinforced Structures

    NASA Technical Reports Server (NTRS)

    Russell, Samuel S.; Walker, James L.; Workman, Gary; Thom, Robert (Technical Monitor)

    2002-01-01

    Thermography inspection is an optic based technology that can reduce the time and cost required to inspect propellant tanks or aero structures fabricated from composite materials. Usually areas identified as suspect in the thermography inspection are examined with ultrasonic methods to better define depth, orientation and the nature of the anomaly. This combination of nondestructive evaluation techniques results in a rapid and comprehensive inspection of composite structures. Examples of application of this inspection philosophy to prototype will be presented. Methods organizing the inspection and evaluating the results will be considered.

  7. Nondestructive evaluation of Ni-Ti shape memory alloy

    SciTech Connect

    Meir, S.; Gordon, S.; Karsh, M.; Ayers, R.; Olson, D. L.; Wiezman, A.

    2011-06-23

    The nondestructive evaluation of nickel titanium (Ni-Ti) alloys for applications such as heat treatment for biomaterials applications (dental) and welding was investigated. Ni-Ti alloys and its ternary alloys are valued for mechanical properties in addition to the shape memory effect. Two analytical approaches were perused in this work. Assessment of the microstructure of the alloy that determines the martensitic start temperature (Ms) of Ni-Ti alloy as a function of heat treatment, and secondly, an attempt to evaluate a Friction Stir Welding, which involves thermo-mechanical processing of the alloy.

  8. Experimental implementation of reverse time migration for nondestructive evaluation applications.

    PubMed

    Anderson, Brian E; Griffa, Michele; Bas, Pierre-Yves Le; Ulrich, Timothy J; Johnson, Paul A

    2011-01-01

    Reverse time migration (RTM) is a commonly employed imaging technique in seismic applications (e.g., to image reservoirs of oil). Its standard implementation cannot account for multiple scattering/reverberation. For this reason it has not yet found application in nondestructive evaluation (NDE). This paper applies RTM imaging to NDE applications in bounded samples, where reverberation is always present. This paper presents a fully experimental implementation of RTM, whereas in seismic applications, only part of the procedure is done experimentally. A modified RTM imaging condition is able to localize scatterers and locations of disbonding. Experiments are conducted on aluminum samples with controlled scatterers. PMID:21302980

  9. Non-destructive evaluation using variable frequency microwaves

    NASA Astrophysics Data System (ADS)

    Siu, Frederick; Siores, Elias; Taube, Alexander; Blicblau, Aaron

    1999-12-01

    Microwave assisted Non-Destructive Evaluation (NDE) technologies have been utilised in industry for materials characterization and quality assessment. This paper discusses the potential of using broadband variable frequency microwaves (2.5-18 GHZ) for diagnosing materials integrity, especially during processing in resonant cavities. The technique is compared to conventional microwave based NDE. Details regarding system configuration with on-line process control and volumetric quality control capabilities are included for microwave curable epoxy test pieces. The principles of microwave interactions with these materials are explained and experimental findings presented.

  10. Liberty Bell 7 Recovery Evaluation and Nondestructive Testing

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I.; Smith, William L.

    1999-01-01

    An inspection of the Mercury capsule, Liberty Bell 7, and its contents was made on September 1 and 2, 1999. The condition of the capsule and its contents was consistent with long-term exposure to salt water and high pressures at the bottom of the ocean. Many of the metallic materials suffered corrosion, whereas the polymer-based materials seem to have survived remarkably well. No identifiable items or structures were found that appeared to have any scientific value. At this time, no further nondestructive evaluation appears to be justified.

  11. Acoustic wave generation by microwaves and applications to nondestructive evaluation.

    PubMed

    Hosten, Bernard; Bacon, Christophe; Guilliorit, Emmanuel

    2002-05-01

    Although acoustic wave generation by electromagnetic waves has been widely studied in the case of laser-generated ultrasounds, the literature on acoustic wave generation by thermal effects due to electromagnetic microwaves is very sparse. Several mechanisms have been suggested to explain the phenomenon of microwave generation, i.e. radiation pressure, electrostriction or thermal expansion. Now it is known that the main cause is the thermal expansion due to the microwave absorption. This paper will review the recent advances in the theory and experiments that introduce a new way to generate ultrasonic waves without contact for the purpose of nondestructive evaluation and control. The unidirectional theory based on Maxwell's equations, heat equation and thermoviscoelasticity predicts the generation of acoustic waves at interfaces and inside stratified materials. Acoustic waves are generated by a pulsed electromagnetic wave or a burst at a chosen frequency such that materials can be excited with a broad or narrow frequency range. Experiments show the generation of acoustic waves in water, viscoelastic polymers and composite materials shaped as rod and plates. From the computed and measured accelerations at interfaces, the viscoelastic and electromagnetic properties of materials such as polymers and composites can be evaluated (NDE). Preliminary examples of non-destructive testing applications are presented. PMID:12159977

  12. Nondestructive Evaluation of Thick Concrete Using Advanced Signal Processing Techniques

    SciTech Connect

    Clayton, Dwight A; Barker, Alan M; Santos-Villalobos, Hector J; Albright, Austin P; Hoegh, Kyle; Khazanovich, Lev

    2015-09-01

    The purpose of the U.S. Department of Energy Office of Nuclear Energy’s Light Water Reactor Sustainability (LWRS) Program is to develop technologies and other solutions that can improve the reliability, sustain the safety, and extend the operating lifetimes of nuclear power plants (NPPs) beyond 60 years [1]. Since many important safety structures in an NPP are constructed of concrete, inspection techniques must be developed and tested to evaluate the internal condition. In-service containment structures generally do not allow for the destructive measures necessary to validate the accuracy of these inspection techniques. This creates a need for comparative testing of the various nondestructive evaluation (NDE) measurement techniques on concrete specimens with known material properties, voids, internal microstructure flaws, and reinforcement locations.

  13. Application of Raman Spectroscopy for Nondestructive Evaluation of Composite Materials

    NASA Technical Reports Server (NTRS)

    Washer, Glenn A.; Brooks, Thomas M. B.; Saulsberry, Regor

    2007-01-01

    This paper will present an overview of efforts to investigate the application of Raman spectroscopy for the characterization of Kevlar materials. Raman spectroscopy is a laser technique that is sensitive to molecular interactions in materials such as Kevlar, graphite and carbon used in composite materials. The overall goal of this research reported here is to evaluate Raman spectroscopy as a potential nondestructive evaluation (NDE) tool for the detection of stress rupture in Kevlar composite over-wrapped pressure vessels (COPVs). Characterization of the Raman spectra of Kevlar yarn and strands will be presented and compared with analytical models provided in the literature. Results of testing to investigate the effects of creep and high-temperature aging on the Raman spectra will be presented.

  14. Theory and experimental technique for nondestructive evaluation of ceramic composites

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    1990-01-01

    The important ultrasonic scattering mechanisms for SiC and Si3N4 ceramic composites were identified by examining the interaction of ultrasound with individual fibers, pores, and grains. The dominant scattering mechanisms were identified as asymmetric refractive scattering due to porosity gradients in the matrix material, and symmetric diffractive scattering at the fiber-to-matrix interface and at individual pores. The effect of the ultrasonic reflection coefficient and surface roughness in the ultrasonic evaluation was highlighted. A new nonintrusive ultrasonic evaluation technique, angular power spectrum scanning (APSS), was presented that is sensitive to microstructural variations in composites. Preliminary results indicate that APSS will yield information on the composite microstructure that is not available by any other nondestructive technique.

  15. Proceedings of the First Annual Symposium for Nondestructive Evaluation of Bond Strength

    NASA Technical Reports Server (NTRS)

    Roberts, Mark J. (Compiler)

    1999-01-01

    Quantitative adhesive bond strength measurement has been an issue for over thirty years. Utilization of nonlinear ultrasonic nondestructive evaluation methods has shown more effectiveness than linear methods on adhesive bond analysis, resulting in an increased sensitivity to changes in bondline conditions. Correlation to changes in higher order material properties due to microstructural changes using nonlinear ultrasonics has been shown and could relate to bond strength. Nonlinear ultrasonic energy is an order of magnitude more sensitive than linear ultrasound to these material parameter changes and to acoustic velocity changes caused by the acoustoelastic effect when a bond is prestressed. This increased sensitivity will assist in getting closer to quantitative measurement of adhesive bond strength. Signal correlations between non-linear ultrasonic measurements and initialization of bond failures have been successfully measured. This paper reviews nonlinear bond strength research efforts presented by university and industry experts at the First Annual Symposium for Nondestructive Evaluation of Bond Strength organized by the NDE Sciences Branch at NASA Langley in November 1997.

  16. Nondestructive evaluation of near-surface residual stress in shot-peened nickel-base superalloys

    NASA Astrophysics Data System (ADS)

    Yu, Feng

    Surface enhancement methods, which produce beneficial compressive residual stresses and increased hardness in a shallow near-surface region, are widely used in a number of industrial applications, including gas-turbine engines. Nondestructive evaluation of residual stress gradients in surface-enhanced materials has great significance for turbine engine component life extension and their reliability in service. It has been recently found that, in sharp contrast with most other materials, shot-peened nickel-base superalloys exhibit an apparent increase in electrical conductivity at increasing inspection frequencies, which can be exploited for nondestructive residual stress assessment. The primary goal of this research is to develop a quantitative eddy current method for nondestructive residual stress profiles in surface-treated nickel-base superalloys. Our work have been focused on five different aspects of this issue, namely, (i) validating the noncontacting eddy current technique for electroelastic coefficients calibration, (ii) developing inversion procedures for determining the subsurface residual stress profiles from the measured apparent eddy current conductivity (AECC), (iii) predicting the adverse effect of surface roughness on the eddy current characterization of shot-peened metals, (iv) separating excess AECC caused by the primary residual stress effect from intrinsic conductivity variations caused by material inhomogeneity, and (v) investigating different mechanisms through which cold work could influence the AECC in surface-treated nickel-base superalloys. The results of this dissertation have led to a better understanding of the underlying physical phenomenon of the measured excess AECC on nickel-base engine alloys, and solved a few critical applied issues in eddy current nondestructive residual stress assessment in surface-treated engine components and, ultimately, contributed to the better utilization and safer operation of the Air Force's aging aircraft fleet.

  17. Remote monitoring and nondestructive evaluation of wind turbine towers

    NASA Astrophysics Data System (ADS)

    Chiang, Chih-Hung; Yu, Chih-Peng; Hsu, Keng-Tsang; Cheng, Chia-Chi; Ke, Ying-Tzu; Shih, Yi-Ru

    2014-03-01

    Wind turbine towers are in need of condition monitoring so as to lower the cost of unexpected maintenance. Wind loading from turbulence and gusts can cause damage in horizontal axis wind turbines even the supporting towers. Monitoring of wind turbines in service using embedded data sensor arrays usually is not targeted at the turbine-tower interaction from the perspective of structural dynamics. In this study the remote monitoring of the tower supporting a horizontal-axis wind turbine was attempted using a microwave interferometer. The dominant frequency of one tower was found to be decreased by more than 20% in 16 months. Numerical modeling using spectral finite elements is in progress and should provide further information regarding frequency shift due to stiffness variation and added mass. Expected outcome will contribute to remote monitoring procedures and nondestructive evaluation techniques for local wind turbine structures during operation.

  18. Nondestructive Evaluation (NDE) for Inspection of Composite Sandwich Structures

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Parker, F. Raymond

    2014-01-01

    Composite honeycomb structures are widely used in aerospace applications due to their low weight and high strength advantages. Developing nondestructive evaluation (NDE) inspection methods are essential for their safe performance. Flash thermography is a commonly used technique for composite honeycomb structure inspections due to its large area and rapid inspection capability. Flash thermography is shown to be sensitive for detection of face sheet impact damage and face sheet to core disbond. Data processing techniques, using principal component analysis to improve the defect contrast, are discussed. Limitations to the thermal detection of the core are investigated. In addition to flash thermography, X-ray computed tomography is used. The aluminum honeycomb core provides excellent X-ray contrast compared to the composite face sheet. The X-ray CT technique was used to detect impact damage, core crushing, and skin to core disbonds. Additionally, the X-ray CT technique is used to validate the thermography results.

  19. Microwave Nondestructive Evaluation of Dielectric Materials with a Metamaterial Lens

    NASA Technical Reports Server (NTRS)

    Shreiber, Daniel; Gupta, Mool; Cravey, Robin L.

    2008-01-01

    A novel microwave Nondestructive Evaluation (NDE) sensor was developed in an attempt to increase the sensitivity of the microwave NDE method for detection of defects small relative to a wavelength. The sensor was designed on the basis of a negative index material (NIM) lens. Characterization of the lens was performed to determine its resonant frequency, index of refraction, focus spot size, and optimal focusing length (for proper sample location). A sub-wavelength spot size (3 dB) of 0.48 lambda was obtained. The proof of concept for the sensor was achieved when a fiberglass sample with a 3 mm diameter through hole (perpendicular to the propagation direction of the wave) was tested. The hole was successfully detected with an 8.2 cm wavelength electromagnetic wave. This method is able to detect a defect that is 0.037 lambda. This method has certain advantages over other far field and near field microwave NDE methods currently in use.

  20. Millimeter-wave imaging for nondestructive evaluation of materials

    SciTech Connect

    Gopalsami, N; Bakhtiari, S.; Dieckman, S.L.; Raptis, A.C.; Lepper, M.J. . Energy Technology Div.)

    1994-03-01

    A millimeter-wave imaging system has been developed in the W band (75--110 GHz) for nondestructive evaluation of low-loss materials. The system employs a focused beam to provide spatial resolution of about one wavelength. A plane-wave model is used to calculate the effective reflection (or transmission) coefficient of a multilayer geometry. Theoretical analysis is used to optimize the measurement frequency for higher image contrast and to interpret the experimental results. Both reflection and transmission images, based on backscattered and forward-scattered powers, were made with Kevlar/epoxy samples containing artificially introduced defects such as subsurface voids and disbonds. The results indicate that millimeter wave imaging has high potential for noncontact detection of defects in low-loss materials.

  1. Linear and nonlinear inversion algorithms applied in nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Marklein, R.; Mayer, K.; Hannemann, R.; Krylow, T.; Balasubramanian, K.; Langenberg, K. J.; Schmitz, V.

    2002-12-01

    Convenient tools for nondestructive evaluation of solids can be electromagnetic and/or elastodynamic waves; since their governing equations, including acoustics, exhibit strong structural similarities, the same inversion concepts apply. In particular, the heuristic SAFT algorithm (synthetic aperture focusing technique) can be - and has been - utilized for all kinds of waves, once a scalar approximation can be justified. Relating SAFT to inverse scattering in terms of diffraction tomography, it turns out that linearization is the most stringent inherent approximation. Hence, the results of nonlinear inversion schemes such as contrast source inversion are compared to the output of SAFT for a carefully designed ultrasonic experiment. In addition, it will be shown via synthetic as well as experimental data that SAFT can be extended to electromagnetic vector fields and to an inhomogeneous and/or anisotropic background material.

  2. Process-interactive nondestructive evaluation for metal-matrix composites

    NASA Astrophysics Data System (ADS)

    Liaw, P. K.; Shannon, R. E.; Clark, W. G., Jr.; Harrigan, W. C., Jr.

    Nondestructive evaluation (NDE) has been conducted on composite products at various stages of fabrication processes including raw powders, powder mixtures, billets and final product extrusions. Eddy current was found to be effective in identifying matrix powder alloy chemistry and particle size, and in determining the mix ratio of silicon carbide (SiC) reinforcement particles in aluminum matrix alloy powders. Ultrasonic techniques were capable of identifying SiC clusters in large-scale, consolidated powder metallurgy (P/M) metal matrix composite (MMC) billets, while eddy current methods could be used to determine near-surface density variations in the billets. Multiple NDE techniques (eddy current, ultrasonics and resistivity) could be employed to quantify microstructural characteristics of composite extrusions. These results suggest that NDE methods can be integrated into manufacturing processes to provide online, closed-loop control of fabrication parameters.

  3. Nondestructive evaluation of aircraft composites using terahertz time domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Stoik, Christopher D.

    Terahertz (THz) time domain spectroscopy (TDS) was assessed as a nondestructive evaluation technique for aircraft composites. Material properties of glass fiber composite were measured using both transmission and reflection configuration. The interaction of THz with a glass fiber composite was then analyzed, including the effects of scattering, absorption, and the index of refraction, as well as effective medium approximations. THz TDS, in both transmission and reflection configuration, was used to study composite damage, including voids, delaminations, mechanical damage, and heat damage. Measurement of the material properties on samples with localized heat damage showed that burning did not change the refractive index or absorption coefficient noticeably; however, material blistering was detected. Voids were located by THz TDS transmission and reflection imaging using amplitude and phase techniques. The depth of delaminations was measured via the timing of Fabry-Perot reflections after the main pulse. Evidence of bending stress damage and simulated hidden cracks was also detected with terahertz imaging.

  4. Nondestructive Evaluation Methodologies Developed for Certifying Composite Flywheels

    NASA Technical Reports Server (NTRS)

    Baaklini, George Y.; Konno, Kevin E.; Martin, Richard E.; Thompson, Richard

    2001-01-01

    Manufacturing readiness of composite rotors and certification of flywheels depend in part on the maturity of nondestructive evaluation (NDE) technology for process optimization and quality assurance, respectively. At the NASA Glenn Research Center, the capabilities and limitations of x-ray-computed tomography and radiography, as well as advanced ultrasonics were established on NDE ring and rotor standards with electrical discharge machining (EDM) notches and drilled holes. Also, intentionally seeded delamination, tow break, and insert of bagging material were introduced in hydroburst-rings to study the NDE detection capabilities of such anomalies and their effect on the damage tolerance and safe life margins of subscale rings and rotors. Examples of possible occurring flaws or anomalies in composite rings as detected by NDE and validated by destructive metallography are shown. The general NDE approach to ensure the quality of composite rotors and to help in the certification of flywheels is briefly outlined.

  5. Non-destructive evaluation method employing dielectric electrostatic ultrasonic transducers

    NASA Technical Reports Server (NTRS)

    Yost, William T. (Inventor); Cantrell, Jr., John H. (Inventor)

    2003-01-01

    An acoustic nonlinearity parameter (.beta.) measurement method and system for Non-Destructive Evaluation (NDE) of materials and structural members novelly employs a loosely mounted dielectric electrostatic ultrasonic transducer (DEUT) to receive and convert ultrasonic energy into an electrical signal which can be analyzed to determine the .beta. of the test material. The dielectric material is ferroelectric with a high dielectric constant .di-elect cons.. A computer-controlled measurement system coupled to the DEUT contains an excitation signal generator section and a measurement and analysis section. As a result, the DEUT measures the absolute particle displacement amplitudes in test material, leading to derivation of the nonlinearity parameter (.beta.) without the costly, low field reliability methods of the prior art.

  6. Nondestructive evaluation of environmental barrier coatings in CFCC combustor liners.

    SciTech Connect

    Sun, J. G.; Benz, J.; Ellingson, W. A.; Kimmel, J. B.; Price, J. R.; Energy Technology; Solar Turbines, Inc

    2007-01-01

    Advanced combustor liners fabricated of SiC/SiC continuous fiber-reinforced ceramic composite (CFCC) and covered with environmental barrier coatings (EBCs) have been successfully tested in Solar Turbines Inc. field engines. The primary goal for the CFCC/EBC liners is to reach a 30,000-h lifetime. Because the EBCs, when applied on the hot surfaces of liners, protect the underlying CFCC from oxidation damage, their performance is critical in achieving the lifetime goal. To determine CFCC/EBC liner condition and assess operating damage, the liners were subjected to nondestructive evaluation (NDE) during various processing stages, as well as before and after the engine test. The NDE techniques included pulsed infrared thermal imaging, air-coupled ultrasonic scanning, and X-ray computerized tomography. It was found that EBC damage and spallation depend on the condition of the CFCC material. The NDE results and correlations with destructive examination are discussed.

  7. Infrared non-destructive evaluation method and apparatus

    DOEpatents

    Baleine, Erwan; Erwan, James F; Lee, Ching-Pang; Stinelli, Stephanie

    2014-10-21

    A method of nondestructive evaluation and related system. The method includes arranging a test piece (14) having an internal passage (18) and an external surface (15) and a thermal calibrator (12) within a field of view (42) of an infrared sensor (44); generating a flow (16) of fluid characterized by a fluid temperature; exposing the test piece internal passage (18) and the thermal calibrator (12) to fluid from the flow (16); capturing infrared emission information of the test piece external surface (15) and of the thermal calibrator (12) simultaneously using the infrared sensor (44), wherein the test piece infrared emission information includes emission intensity information, and wherein the thermal calibrator infrared emission information includes a reference emission intensity associated with the fluid temperature; and normalizing the test piece emission intensity information against the reference emission intensity.

  8. Physical model assisted probability of detection in nondestructive evaluation

    SciTech Connect

    Li, M.; Meeker, W. Q.; Thompson, R. B.

    2011-06-23

    Nondestructive evaluation is used widely in many engineering and industrial areas to detect defects or flaws such as cracks inside parts or structures during manufacturing or for products in service. The standard statistical model is a simple empirical linear regression between the (possibly transformed) signal response variables and the (possibly transformed) explanatory variables. For some applications, such a simple empirical approach is inadequate. An important alternative approach is to use knowledge of the physics of the inspection process to provide information about the underlying relationship between the response and explanatory variables. Use of such knowledge can greatly increase the power and accuracy of the statistical analysis and enable, when needed, proper extrapolation outside the range of the observed explanatory variables. This paper describes a set of physical model-assisted analyses to study the capability of two different ultrasonic testing inspection methods to detect synthetic hard alpha inclusion and flat-bottom hole defects in a titanium forging disk.

  9. Acoustic diagnosis for nondestructive evaluation of ceramic coatings on steel substrates

    SciTech Connect

    Aizawa, Tatsuhiko; Kihara, Junji; Ito, Manabu

    1995-11-01

    New methodology is proposed and developed to make quantitative nondestructive evaluation of TiN coated SKH steel substrates. Since the measured acoustic structure is in precise correspondence with the multi-layered elastic media, change of elastic properties by degradation and damage can be easily distinguished by the acoustic spectro microscopy. In particular, rather complex acoustic structure can be measured by the present method for ceramic coated steel substrate system, but it is completely described by the two-layer model in two dimensional elasticity. Typical example is the cut-off phenomenon where the dispersion curve for the leaky surface wave velocity is forced to be terminated by alternative activation of shear wave instead of it. The quantitative nondestructive diagnosis was developed on the basis of this predictable acoustic structure. Furthermore, the effect of coating conditions on the acoustic structure is also discussed to make residual stress distribution analysis in coating by the acoustic spectro microscopy with reference to the X-ray stress analysis. Some comments are made on further advancement of the present acoustic spectro microscopy adaptive to precise characterization of ceramic coatings and practical sensing system working in practice.

  10. Non-Destructive Evaluation of Thermal Spray Coating Interface Quality by Eddy Current Method

    SciTech Connect

    B.Mi; X. Zhao; R. Bayles

    2006-05-26

    Thermal spray coating is usually applied through directing molten or softened particles at very high velocities onto a substrate. An eddy current non-destructive inspection technique is presented here for thermal spray coating interface quality characterization. Several high-velocity-oxy-fuel (HVOF) coated steel plates were produced with different surface preparation conditions before applying the coating, e.g., grit-blasted surface, wire-brush cleaned surface, and a dirty surface. A quad-frequency eddy current probe was used to manually scan over the coating surface to evaluate the bonding quality. Experimental results show that the three surface preparation conditions can be successfully differentiated by looking into the impedance difference observed from the eddy current probe. The measurement is fairly robust and consistent. More specimens are also prepared with variations of process parameters, such as spray angle, stand-off distance, and application of corrosion protective sealant, etc. They are blindly tested to evaluate the reliability of the eddy current system. Quantitative relations between the coating bond strength and the eddy current response are also established with the support of destructive testing. This non-contact, non-destructive, easy to use technique has the potential for evaluating the coating quality immediately after its application so that any defects can be corrected immediately.

  11. Nondestructive evaluation of weld defects by infrared thermography

    SciTech Connect

    Satonaka, Shinobu; Ohba, Hiroyasu; Shinozaki, Kenya

    1995-12-31

    In order to clarify the applicability of infrared thermography to the nondestructive evaluation of weld defects, an infrared measurement was conducted on the welds with various artificial defects. Two heating methods, a moving gas flame and a Joule effect by electric current flow, were used for the fast and large area inspection with readily interpretable images of defects. Finite element analysis was also used for the theoretical analyses of beat conduction and electric current flow, together with the development of imaging technique for the evaluation of the shape and size of defects. As the results of infrared measurements and theoretical analyses, the selection of heating method and the acquisition of infrared images were important for the clear image and precise measurement of weld defects. As for the clear images, the Joule effect heating was useful for the detection of open-to-the-surface defects, while the moving gas flame heating was available to the inner defect parallel to the surface. It was also clarified that the types of defects were identified by the distribution of high and low temperature regions. In the measurement of defect size, defect edges were evaluated by the positions with maximum temperature gradient in the moving gas flame heating, and with minimum second derivative of temperature in the Joule effect heating. The effective images for the precise measurement of defect size were obtained from the ones immediately after current flow in the Joule effect heating, and just before the arrival of gas flame beneath the defect.

  12. High resolution ultrasonic spectroscopy system for nondestructive evaluation

    NASA Technical Reports Server (NTRS)

    Chen, C. H.

    1991-01-01

    With increased demand for high resolution ultrasonic evaluation, computer based systems or work stations become essential. The ultrasonic spectroscopy method of nondestructive evaluation (NDE) was used to develop a high resolution ultrasonic inspection system supported by modern signal processing, pattern recognition, and neural network technologies. The basic system which was completed consists of a 386/20 MHz PC (IBM AT compatible), a pulser/receiver, a digital oscilloscope with serial and parallel communications to the computer, an immersion tank with motor control of X-Y axis movement, and the supporting software package, IUNDE, for interactive ultrasonic evaluation. Although the hardware components are commercially available, the software development is entirely original. By integrating signal processing, pattern recognition, maximum entropy spectral analysis, and artificial neural network functions into the system, many NDE tasks can be performed. The high resolution graphics capability provides visualization of complex NDE problems. The phase 3 efforts involve intensive marketing of the software package and collaborative work with industrial sectors.

  13. Use of an ultrasonic-acoustic technique for nondestructive evaluation of fiber composite strength

    NASA Technical Reports Server (NTRS)

    Vary, A.; Bowles, K. J.

    1978-01-01

    This report describes the ultrasonic-acoustic technique used to measure a 'Stress Wave Factor'. In a prior study this factor was found effective in evaluating the interlaminar shear strength of fiber-reinforced composites. Details of the method used to measure the stress wave factor are described. In addition, frequency spectra of the stress waves are analyzed in order to clarify the nature of the wave phenomena involved. The stress wave factor can be measured with simple contact probes requiring only one-side access to a part. This is beneficial in nondestructive evaluations because the waves can run parallel to fiber directions and thus measure material properties in directions assumed by actual loads. Moreover, the technique can be applied where conventional through transmission techniques are impractical or where more quantitative data are required. The stress wave factor was measured for a series of graphite/polyimide composite panels and results obtained are compared with through transmission immersion ultrasonic scans.

  14. Optical coherence tomography for nondestructive evaluation of fuel rod degradation

    NASA Astrophysics Data System (ADS)

    Renshaw, Jeremy B.; Jenkins, Thomas P.; Buckner, Benjamin D.; Friend, Brian

    2015-03-01

    Nuclear power plants regularly inspect fuel rods to ensure safe and reliable operation. Excessive corrosion can cause fuel failures which can have significant repercussions for the plant, including impacts on plant operation, worker exposure to radiation, and the plant's INPO rating. While plants typically inspect for fuel rod corrosion using eddy current techniques, these techniques have known issues with reliability in the presence of tenacious, ferromagnetic crud layers that can deposit during operation, and the nondestructive evaluation (NDE) inspection results can often be in error by a factor of 2 or 3. For this reason, alternative measurement techniques, such as Optical Coherence Tomography (OCT), have been evaluated that are not sensitive to the ferromagnetic nature of the crud. This paper demonstrates that OCT has significant potential to characterize the thickness of crud layers that can deposit on the surfaces of fuel rods during operation. Physical trials have been performed on simulated crud samples, and the resulting data show an apparent correlation between the crud layer thickness and the OCT signal.

  15. Nondestructive evaluation of ceramic candle filter with various boundary conditions

    SciTech Connect

    Chen, H.L.; Kiriakidis, A.C.

    2005-06-01

    Nondestructive evaluation (NDE) using a dynamic characterization technique was conducted to study ceramic candle filters. Ceramic candle filters are hollow cylindrical structures made of porous ceramic materials used to protect gas turbine in coal-fired power plants. Deterioration and failure of ceramic filters occurs after being exposed to high-temperature and high-pressure operational environment over a period of time. This paper focuses on the development of an NDE method that can predict the in-situ structural stiffness of the candle filters while still being attached to the plenum. A combination of laboratory testing, theoretical analysis, and finite element method (FEM) simulations are presented. The candle filters were tested using a laser vibrometer/accelerometer setup with variable boundary restraints. A variable end-restraint Timoshenko beam equation was derived to determine the dynamic response of the candle filters with simulated in-situ boundary conditions. Results from the FEM simulation were verified with the analysis to determine the stiffness degradation of the candle filters as well as the boundary conditions. Results from this study show that the vibration characteristics can be used effectively to evaluate both the structural stiffness and the in-situ boundary restraints of the ceramic candle filters during field inspections.

  16. Study Methods to Characterize and Implement Thermography Nondestructive Evaluation (NDE)

    NASA Technical Reports Server (NTRS)

    Walker, James L.

    1998-01-01

    The limits and conditions under which an infrared thermographic nondestructive evaluation can be utilized to assess the quality of aerospace hardware is demonstrated in this research effort. The primary focus of this work is on applying thermography to the inspection of advanced composite structures such as would be found in the International Space Station Instrumentation Racks, Space Shuttle Cargo Bay Doors, Bantam RP-1 tank or RSRM Nose Cone. Here, the detection of delamination, disbond, inclusion and porosity type defects are of primary interest. In addition to composites, an extensive research effort has been initiated to determine how well a thermographic evaluation can detect leaks and disbonds in pressurized metallic systems "i.e. the Space Shuttle Main Engine Nozzles". In either case, research into developing practical inspection procedures was conducted and thermographic inspections were performed on a myriad of test samples, subscale demonstration articles and "simulated" flight hardware. All test samples were fabricated as close to their respective structural counterparts as possible except with intentional defects for NDE qualification. As an added benefit of this effort to create simulated defects, methods were devised for defect fabrication that may be useful in future NDE qualification ventures.

  17. Research in nondestructive evaluation techniques for nuclear reactor concrete structures

    SciTech Connect

    Clayton, Dwight; Smith, Cyrus

    2014-02-18

    The purpose of the Materials Aging and Degradation (MAaD) Pathway of the Department of Energy's Light Water Reactor Sustainability (LWRS) Program is to develop the scientific basis for understanding and predicting longterm environmental degradation behavior of material in nuclear power plants and to provide data and methods to assess the performance of systems, structures, and components (SSCs) essential to safe and sustained nuclear power plant operations. The understanding of aging-related phenomena and their impacts on SSCs is expected to be a significant issue for any nuclear power plant planning for long-term operations (i.e. service beyond the initial license renewal period). Management of those phenomena and their impacts during long-term operations can be better enable by improved methods and techniques for detection, monitoring, and prediction of SSC degradation. The MAaD Pathway R and D Roadmap for Concrete, 'Light Water Reactor Sustainability Nondestructive Evaluation for Concrete Research and Development Roadmap', focused initial research efforts on understanding the recent concrete issues at nuclear power plants and identifying the availability of concrete samples for NDE techniques evaluation and testing. [1] An overview of the research performed by ORNL in these two areas is presented here.

  18. Optical coherence tomography for nondestructive evaluation of fuel rod degradation

    SciTech Connect

    Renshaw, Jeremy B.; Jenkins, Thomas P. Buckner, Benjamin D.; Friend, Brian

    2015-03-31

    Nuclear power plants regularly inspect fuel rods to ensure safe and reliable operation. Excessive corrosion can cause fuel failures which can have significant repercussions for the plant, including impacts on plant operation, worker exposure to radiation, and the plant's INPO rating. While plants typically inspect for fuel rod corrosion using eddy current techniques, these techniques have known issues with reliability in the presence of tenacious, ferromagnetic crud layers that can deposit during operation, and the nondestructive evaluation (NDE) inspection results can often be in error by a factor of 2 or 3. For this reason, alternative measurement techniques, such as Optical Coherence Tomography (OCT), have been evaluated that are not sensitive to the ferromagnetic nature of the crud. This paper demonstrates that OCT has significant potential to characterize the thickness of crud layers that can deposit on the surfaces of fuel rods during operation. Physical trials have been performed on simulated crud samples, and the resulting data show an apparent correlation between the crud layer thickness and the OCT signal.

  19. In-process nondestructive evaluation of the pultrusion process

    NASA Astrophysics Data System (ADS)

    Fecko, David L.; Heider, Dirk; Gillespie, John W., Jr.; Steiner, Karl V.

    1995-07-01

    Substantial growth potential for composite materials exists in the private sector, where high volume, low cost production is required. Post processing inspection can represent a significant percentage of the cost of composite products. Alternate ways of assuring quality must be examined. In-process inspection can be easily adapted to continuous composite manufacturing techniques such as the pultrusion process, enabling 100% inspection. Recent research efforts at the Center for Composite Materials has focused on ways of evaluating pultruded composites on-line by using ultrasonic non-destructive evaluation (NDE) techniques. The most accurate method to date is based upon Lamb wave velocity measurements. This inspection technique uses two transducers positioned at normal incidence to the composite in a through-transmission mode to generate and receive ultrasonic waves which propagate through the sample. Careful processing of the waveform data reveals the degree of porosity in the composite samples. A series of tests were performed in-situ on an actual laboratory scale pultrusion process which accurately predicted the porosity in a 6.4 mm multiplied by 3.2 mm (0.25' multiplied by 0.125') cross-section pultruded rod over a range of 0.5% to 12% void volume fraction.

  20. Longitudinal nondestructive evaluation of new utility wood poles

    SciTech Connect

    Anthony, R.W.; Bodig, J.; Phillips, G.E.; Brooks, R.T. )

    1992-10-01

    This report describes the development of a nondestructive evaluation (NDE) methodology for assessing the bending strength of new wood utility poles. Fundamental concepts of stress wave propagation are presented. The development of a longitudinal stress wave methodology for predicting pole strength and the results of destructive tests on full-size poles are described. Mathematical correlations between stress wave parameters, geometric characteristics, and individual pole bending strengths form the basis of strength prediction models for western redcedar, Douglas-fir and southern pine poles. Models were developed for NDE in the whitewood stage and after preservative treatment of poles. For each species the two most commonly used preservative types were evaluated. Excellent correlations were obtained for western redcedar and Douglas-fir poles, but high moisture content in the southern pine poles resulted in lower prediction accuracies for this species. Verification of the developed mathematical models demonstrates that improvement in classifying poles into the ANSI 05.1 tip-load capacities is technically feasible. The development and field trial of the prototype equipment for strength grading of new poles is also described. Research results can be used to benefit utilities by enabling the supply of strength graded poles with a higher accuracy than previously possible.

  1. Non-destructive evaluation of anchorage zones by ultrasonics techniques.

    PubMed

    Kharrat, M; Gaillet, L

    2015-08-01

    This work aims to evaluate the efficiency and reliability of two Non-Destructive Testing (NDT) methods for damage assessment in bridges' anchorages. The Acousto-Ultrasonic (AU) technique is compared to classical Ultrasonic Testing (UT) in terms of defect detection and structural health classification. The AU technique is firstly used on single seven-wire strands damaged by artificial defects. The effect of growing defects on the waves traveling through the strands is evaluated. Thereafter, three specimens of anchorages with unknown defects are inspected by the AU and UT techniques. Damage assessment results from both techniques are then compared. The structural health conditions of the specimens can be then classified by a damage severity criterion. Finally, a damaged anchorage socket with mastered defects is controlled by the same techniques. The UT allows the detection and localization of damaged wires. The AU technique is used to bring out the effect of defects on acoustic features by comparing a healthy and damaged anchorage sockets. It is concluded that the UT method is suitable for local and crack-like defects, whereas the AU technique enables the assessment of the global structural health of the anchorage zones. PMID:25824342

  2. Nondestructive evaluation of hydrogel mechanical properties using ultrasound

    PubMed Central

    Walker, Jason M.; Myers, Ashley M.; Schluchter, Mark D.; Goldberg, Victor M.; Caplan, Arnold I.; Berilla, Jim A.; Mansour, Joseph M.; Welter, Jean F.

    2012-01-01

    The feasibility of using ultrasound technology as a noninvasive, nondestructive method for evaluating the mechanical properties of engineered weight-bearing tissues was evaluated. A fixture was designed to accurately and reproducibly position the ultrasound transducer normal to the test sample surface. Agarose hydrogels were used as phantoms for cartilage to explore the feasibility of establishing correlations between ultrasound measurements and commonly used mechanical tissue assessments. The hydrogels were fabricated in 1–10% concentrations with a 2–10 mm thickness. For each concentration and thickness, six samples were created, for a total of 216 gel samples. Speed of sound was determined from the time difference between peak reflections and the known height of each sample. Modulus was computed from the speed of sound using elastic and poroelastic models. All ultrasonic measurements were made using a 15 MHz ultrasound transducer. The elastic modulus was also determined for each sample from a mechanical unconfined compression test. Analytical comparison and statistical analysis of ultrasound and mechanical testing data was carried out. A correlation between estimates of compressive modulus from ultrasonic and mechanical measurements was found, but the correlation depended on the model used to estimate the modulus from ultrasonic measurements. A stronger correlation with mechanical measurements was found using the poroelastic rather than the elastic model. Results from this preliminary testing will be used to guide further studies of native and engineered cartilage. PMID:21773854

  3. Nondestructive evaluation techniques for nickel-cadmium aerospace battery cells

    NASA Technical Reports Server (NTRS)

    Haak, R.; Tench, D.

    1982-01-01

    The ac impedance characteristics of Ni-Cd cells as an in-situ, nondestructive means of determining cell lifetime, particularly with respect to the probability of premature failure were evaluated. Emphasis was on evaluating Ni-Cd cell impedance over a wide frequency range (10,000 to 0.0004 Hz) as the cells were subjected to charge/discharge cycle testing. The results indicate that cell degradation is reflected in the low frequency (Warburg) impedance characteristics associated with diffusion processes. The Warburg slope (W) was found to steadily increase as a function of cell aging for completely discharged cells. In addition, based on data for two cells, a high or rapidly increasing value for W signals imminent cell failure by one mechanism. Degradation by another mechanism is apparently reflected in a fall-off (roll-over) of W at lower frequencies. As a secondary result, the frequency dependence of the absolute cell impedance at low frequencies (5 - 500 mHz) was found to be a good indication of the cell state-of-charge.

  4. Incorporation of nondestructive evaluation in Pontis Bridge Management System

    NASA Astrophysics Data System (ADS)

    Hadavi, Ahmad

    1998-03-01

    The highway system in the United States includes nearly 577,000 bridges, the majority of which were built during two major bridge building periods -- just before World War II (1930s) and in the first two decades of the Cold War (1950s and 1960s). Given the age and increased usage of these bridges over the years, many now require substantial maintenance to satisfy their desired level of service. The complex task of allocating scarce funds for the repair, maintenance, and rehabilitation of this large number of bridges led to the development of several optimization studies and two major bridge management system, namely BRIDGIT and Pontis. Pontis has emerged as the system of choice for all states in the Nation. At this time over 40 highway agencies continue to license, evaluate and implement the current AASHTOWARE Program, Pontis V. 3.2. However, all data currently required by Pontis to assess the structural stability and resulting suggestions for repair and maintenance of bridges are based on visual inspection and judgement. Consequently, all suggestions are based on that visual inspection. This paper discusses development of a plan for how non-destructive evaluation (NDE) data can be used to provide more information than visual inspection.

  5. Research in nondestructive evaluation techniques for nuclear reactor concrete structures

    NASA Astrophysics Data System (ADS)

    Clayton, Dwight; Smith, Cyrus

    2014-02-01

    The purpose of the Materials Aging and Degradation (MAaD) Pathway of the Department of Energy's Light Water Reactor Sustainability (LWRS) Program is to develop the scientific basis for understanding and predicting longterm environmental degradation behavior of material in nuclear power plants and to provide data and methods to assess the performance of systems, structures, and components (SSCs) essential to safe and sustained nuclear power plant operations. The understanding of aging-related phenomena and their impacts on SSCs is expected to be a significant issue for any nuclear power plant planning for long-term operations (i.e. service beyond the initial license renewal period). Management of those phenomena and their impacts during long-term operations can be better enable by improved methods and techniques for detection, monitoring, and prediction of SSC degradation. The MAaD Pathway R&D Roadmap for Concrete, "Light Water Reactor Sustainability Nondestructive Evaluation for Concrete Research and Development Roadmap", focused initial research efforts on understanding the recent concrete issues at nuclear power plants and identifying the availability of concrete samples for NDE techniques evaluation and testing. [1] An overview of the research performed by ORNL in these two areas is presented here.

  6. The thermographic nondestructive evaluation of iron aluminide green sheet

    NASA Astrophysics Data System (ADS)

    Watkins, Michael Lee

    The recent development of manufacturing techniques for the fabrication of thin iron aluminide sheet requires advanced quantitative methods for on-line inspection. An understanding of the mechanisms responsible for flaws and the development of appropriate flaw detection methods are key elements in an effective quality management system. The first step in the fabrication of thin FeAl alloy sheet is the formation of a green sheet by cold rolling FeAl powder mixed with organic binding agents. The green sheet composite has a bulk density, which is typically less than about 3.6 g/cc. The finished sheet, with a density of about 6.1 g/cc, is obtained using a series of process steps involving binder elimination, densification, sintering, and annealing. Non-uniformities within the green sheet are the major contributor to material failure in subsequent sheet processing and the production of non-conforming finished sheet. The production environment and physical characteristics of the composite provide for unique challenges in developing a rapid nondestructive inspection capability. The method must be non-contact due to the fragile nature of the composite. Limited access to the material also demands a one-sided inspection technique. An active thermographic method providing for 100% on-line inspection within an industrial, process has been developed. This approach is cost competitive with alternative technologies, such as x-ray imaging systems, and provides the required sensitivity to the variations in material composition. The mechanism of flaw formation and the transformation of green sheet flaws into defects that appear in intermediate and finished sheet products are described. A mathematical model which describes the green sheet heat transfer propagation, in the context of the inspection technique and the compact heterogeneity, is also presented. The potential for feedback within the production process is also discussed.

  7. Review of progress in quantitative nondestructive evaluation; Proceedings of the 17th Annual Review, University of California, La Jolla, CA, July 15-20, 1990. Vols. 10A and 10B

    SciTech Connect

    Thompson, D.O.; Chimenti, D.E. Iowa State University of Science and Technology, Ames Johns Hopkins University, Baltimore, MD )

    1991-01-01

    Various papers on quantitative NDE are presented. The general topics discussed include: fundamentals of standard techniques as they apply to elastic wave scattering, elastic wave propagation, eddy currents, radiography and CT; evolving techniques in computed tomography, laser-based methods, and exploratory techniques; interpretative signal and image processing in neural networks, signal processing, and image processing; probes and sensors in ultrasonic transducers, electromagnetic field probes, eddy current arrays, imaging, and process control; electronic and ceramic materials; engineered materials for smart structures, joints, and composites; characterization of materials, including the properties, nonlinear acoustic properties, deformation and fracture, and relationship of acoustoelasticity to stress and texture; instruments and systems; and manufacturing and reliability.

  8. Nondestructive Evaluation Methods for the Ares I Common Bulkhead

    NASA Technical Reports Server (NTRS)

    Walker, James

    2010-01-01

    A large scale bonding demonstration test article was fabricated to prove out manufacturing techniques for the current design of the NASA Ares I Upper Stage common bulkhead. The common bulkhead serves as the single interface between the liquid hydrogen and liquid oxygen portions of the Upper Stage propellant tank. The bulkhead consists of spin-formed aluminum domes friction stir welded to Y-rings and bonded to a perforated phenolic honeycomb core. Nondestructive evaluation methods are being developed for assessing core integrity and the core-to-dome bond line of the common bulkhead. Detection of manufacturing defects such as delaminations between the core and face sheets as well as service life defects such as crushed or sheared core resulting from impact loading are all of interest. The focus of this work will be on the application of thermographic, shearographic, and phased array ultrasonic methods to the bonding demonstration article as well as various smaller test panels featuring design specific defect types and geometric features.

  9. Synchronized Electronic Shutter System (SESS) for Thermal Nondestructive Evaluation

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.

    2001-01-01

    The purpose of this paper is to describe a new method for thermal nondestructive evaluation. This method uses a synchronized electronic shutter system (SESS) to remove the heat lamp's influence on the thermal data during and after flash heating. There are two main concerns when using flash heating. The first concern is during the flash when the photons are reflected back into the camera. This tends to saturate the detectors and potentially introduces unknown and uncorrectable errors when curve fitting the data to a model. To address this, an electronically controlled shutter was placed over the infrared camera lens. Before firing the flash lamps, the shutter is opened to acquire the necessary background data for offset calibration. During flash heating, the shutter is closed to prevent the photons from the high intensity flash from saturating the camera's detectors. The second concern is after the flash heating where the lamps radiate heat after firing. This residual cooling introduces an unwanted transient thermal response into the data. To remove this residual effect, a shutter was placed over the flash lamps to block the infrared heat radiating from the flash head after heating. This helped to remove the transient contribution of the flash. The flash lamp shutters were synchronized electronically with the camera shutter. Results are given comparing the use of the thermal inspection with and without the shutter system.

  10. Non-Destructive Evaluation (NDE) Applications of THz Radiation

    NASA Astrophysics Data System (ADS)

    Zimdars, David

    2005-03-01

    The technology and applications of time domain terahertz (THz) imaging to non-destructive evaluation (NDE) will be discussed. THz imaging has shown great promise in 2 and 3 dimensional non-contact inspection of non-conductive materials such as plastics, foam, composites, ceramics, paper, wood and glass. THz imaging employs safe low power non-ionizing electromagnetic pulses, with lateral resolution < 200 um, and depth resolution < 50 um. THz pulses can be analyzed spectroscopically to reveal chemical content. Recently, highly integrated turn-key THz imaging systems have been introduced commercially. We will demonstrate the detection of voids and disbonds intentionally incorporated within the sprayed on foam insulation of a space shuttle external tank mock-up segments. An industrially hardened THz scanning system which has been deployed to scan the space shuttle tank with small remote transceiver will be described. Additional terahertz security imaging applications for the detection of weapons and explosives will also be discussed, as well as the application of terahertz sensors for high speed industrial process monitoring and quality control.

  11. Distinguishing between uncertainty and variability in nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Li, M.; Spencer, F. W.; Meeker, W. Q.

    2012-05-01

    In nondestructive evaluation (NDE), measurement outputs usually involve different sources of variability such as operator variation, flaw-morphology variation, setup and calibration variation, environmental related variations, and measurement error. If an appropriate experiment is conducted, it is possible to estimate the separate effects of different sources of variability. These sources of variability imply that the Probability of Detection (POD) itself is random depending, for example, on the operator assigned to do the inspection. Traditional POD analysis has focused on the estimation of the mean of the POD distribution (i.e., estimating a POD averaged over the different sources of variability reflected in the data), also providing an associated 95% lower confidence bound to reflect statistical uncertainty (i.e., uncertainty due to limited data). Focusing on mean POD obscures the process variability and has the potential to provide an overly optimistic impression of POD when there is considerable variation. An alternative, commonly used in other areas of statistical analysis, such as product reliability, is to make inferences on a lower quantile of the distribution. In this paper, we emphasize the important difference between mean POD and quantile POD and provide guidance about when they should be used.

  12. Development of nondestructive evaluation methods for structural ceramics

    SciTech Connect

    Ellingson, W.A.; Koehl, R.D.; Wilson, J.A.; Stuckey, J.B.; Engel, H.P.

    1996-04-01

    Nondestructive evaluation (NDE) methods using three-dimensional microfocus X-ray computed tomographic imaging (3DXCT) were employed to map axial and radial density variations in hot-gas filters and heat exchanger tubes. 3D XCT analysis was conducted on (a) two 38-mm-OD, 6.5-mm wall, SiC/SiC heat exchanger tubes infiltrated by CVI; (b) eight 10 cm diam. oxide/oxide heat exchanger tubes; and (c) one 26-cm-long Nextel fiber/SiC matrix hot-gas filter. The results show that radial and axial density uniformity as well as porosity, can be assessed by 3D XCT. NDE methods are also under development to assess thermal barrier coatings which are under development as methods to protect gas-turbine first-stage hot section metallic substrates. Further, because both shop and field joining of CFCC materials will be necessary, work is now beginning on development of NDE methods for joining.

  13. Development of nondestructive evaluation methods for structural ceramics.

    SciTech Connect

    Ellingson, W. A.

    1998-08-19

    During the past year, the focus of our work on nondestructive evaluation (NDE) methods was on the development and application of these methods to technologies such as ceramic matrix composite (CMC) hot-gas filters, CMC high-temperature heat exchangers, and CMC ceramic/ceramic joining. Such technologies are critical to the ''Vision 21 Energy-Plex Fleet'' of modular, high-efficiency, low-emission power systems. Specifically, our NDE work has continued toward faster, higher sensitivity, volumetric X-ray computed tomographic imaging with new amorphous silicon detectors to detect and measure axial and radial density variations in hot-gas filters and heat exchangers; explored the potential use of high-speed focal-plane-array infrared imaging technology to detect delaminations and variations in the thermal properties of SiC/SiC heat exchangers; and explored various NDE methods to characterize CMC joints in cooperation with various industrial partners. Work this year also addressed support of Southern Companies Services Inc., Power Systems Development Facility, where NDE is needed to assess the condition of hot-gas candle filters. This paper presents the results of these efforts.

  14. High resolution x-ray sensor for nondestructive evaluation

    SciTech Connect

    Nagarkar, V.V.; Gordon, J.S.; Vasile, S.; Gothoskar, P.; Hopkins, F.

    1996-06-01

    Nondestructive evaluation (NDE) using X-rays is becoming indispensable for detecting microdefects in new materials currently used in aerospace and other engineering disciplines. Existing X-ray sensors pose limitations on the speed of operation due to persistence of the sensor and a problematic tradeoff between the sensor thickness and spatial resolution. To address these limitations the authors are developing a large area structured CsI(Tl) imaging sensor for NDE using CCD based radiographic and computed tomographic systems. The sensor is formed by vapor deposition of CsI(Tl) onto a specially designed fiberoptic substrate. The work has produced X-ray sensors with a factor of 4.5 greater light output, at least three orders of magnitude faster decay time response, and greater spatial resolution (16% modulation transfer function, MTF(f), at 14 linepairs per millimeter (lp/mm)) compared to the currently used high density Tb{sub 2}O{sub 3} doped fiberoptic glass scintillators. These performance advances will address the limitations of existing detector technology by producing high quality images and fast scan times required for real-time NDE inspection. Performance measurements for prototype CsI(Tl) scintillator converters are presented. With these new sensors the development of larger area fiberoptic taper based CCD detectors with millisecond data acquisition capabilities and high spatial resolution suitable for NDE applications will be possible.

  15. Non-destructive evaluation of coating thickness using guided waves

    NASA Astrophysics Data System (ADS)

    Ostiguy, Pierre-Claude; Quaegebeur, Nicolas; Masson, Patrice

    2015-04-01

    Among existing strategies for non-destructive evaluation of coating thickness, ultrasonic methods based on the measurement of the Time-of-Flight (ToF) of high frequency bulk waves propagating through the thickness of a structure are widespread. However, these methods only provide a very localized measurement of the coating thickness and the precision on the results is largely affected by the surface roughness, porosity or multi-layered nature of the host structure. Moreover, since the measurement is very local, inspection of large surfaces can be time consuming. This article presents a robust methodology for coating thickness estimation based on the generation and measurement of guided waves. Guided waves have the advantage over ultrasonic bulk waves of being less sensitive to surface roughness, and of measuring an average thickness over a wider area, thus reducing the time required to inspect large surfaces. The approach is based on an analytical multi-layer model and intercorrelation of reference and measured signals. The method is first assessed numerically for an aluminum plate, where it is demonstrated that coating thickness can be measured within a precision of 5 micrometers using the S0 mode at frequencies below 500 kHz. Then, an experimental validation is conducted and results show that coating thicknesses in the range of 10 to 200 micrometers can be estimated within a precision of 10 micrometers of the exact coating thickness on this type of structure.

  16. Non-Destructive Evaluation of Materials via Ultraviolet Spectroscopy

    NASA Technical Reports Server (NTRS)

    Pugel, Betsy

    2008-01-01

    A document discusses the use of ultraviolet spectroscopy and imaging for the non-destructive evaluation of the degree of cure, aging, and other properties of resin-based composite materials. This method can be used in air, and is portable for field use. This method operates in reflectance, absorbance, and luminescence modes. The ultraviolet source is used to illuminate a composite surface of interest. In reflectance mode, the reflected response is acquired via the imaging system or via the spectrometer. The spectra are analyzed for organic compounds (conjugated organics) and inorganic compounds (semiconducting band-edge states; luminescing defect states such as silicates, used as adhesives for composite aerospace applications; and metal oxides commonly used as thermal coating paints on a wide range of spacecraft). The spectra are compared with a database for variation in conjugation, substitution, or length of molecule (in the case of organics) or band edge position (in the case of inorganics). This approach is useful in the understanding of material quality. It lacks the precision in defining the exact chemical structure that is found in other materials analysis techniques, but it is advantageous over methods such as nuclear magnetic resonance, infrared spectroscopy, and chromatography in that it can be used in the field to assess significant changes in chemical structure that may be linked to concerns associated with weaknesses or variations in structural integrity, without disassembly of or destruction to the structure of interest.

  17. Micromachined ultrasonic transducers for air-coupled nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Hansen, Sean T.; Degertekin, F. Levent; Khuri-Yakub, Butrus T.

    1999-01-01

    Conventional methods of ultrasonic non-destructive evaluation (NDE) use liquids to couple sound waves into the test samples. This either requires immersion of the parts to be examined or the use of complex and bulky water squirting systems that must be scanned over the structure. Air-coupled ultrasonic systems eliminate these requirements if the losses at air-solid interfaces are tolerable. Micromachined capacitive ultrasonic transducers (cMUTs) have been shown to have more than 100 dB dynamic range when used in the bistatic transmission mode. In this paper, we present results of a pitch-catch transmission system using cMUTs that achieves a 103 dB dynamic range. Each transducer consists of 10,000 silicon nitride membranes of 100 micrometers diameter connected in parallel. This geometry result in transducers with a resonant frequency around 2.3 MHz. These transducers can be used in transmission experiments at normal incident to the sample or to excite and detect guided waves in aluminum and composite plates. In this paper we present ultrasonic defect detection results from both through transmission and guided Lamb wave experiments in aluminum and composite plates, such as those used in aircraft.

  18. A calibration procedure for sonic infrared nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Morbidini, M.; Cawley, P.

    2009-07-01

    Sonic infrared is potentially a very attractive nondestructive evaluation technique offering the possibility of rapid testing of complex components. However, at present it is difficult to be sure that sufficient excitation has been applied so that a null (no defect present) result can be trusted. This paper presents a calibration method to improve the reliability of the technique. The method uses a measurement of the vibration of the component during the test, the vibration signal being processed to give a "heating index" which is a measure of the ability of the vibration field to generate heat at any defects of interest that are present. The calculation of the heating index and the rationale for its formulation are described. The method is then applied on two sets of beamlike specimens with cracks of different sizes. The maximum temperature rise in successive tests on a given specimen is shown to correlate well with the maximum heating index, so validating the method. The threshold heating index required to reliably detect cracks as a function of crack size is discussed and practical calibration and test procedures are proposed.

  19. Overview of Mathematical Modeling in Nondestructive Evaluation (NDE)

    NASA Astrophysics Data System (ADS)

    Aldrin, John C.

    2002-09-01

    This report presents a broad overview of mathematical modeling in nondestructive evaluation (NDE). The primary emphasis is to expand the review of NDE modeling literature covered by previous general works. To provide a starting point for researchers and engineers, the discussions and references include multiple modeling approaches (analytical, asymptotic, and numerical) for a variety of NDE techniques. A second emphasis for this report is to present the pertinent modeling software packages for a variety of NDE techniques. Overviews of modeling for four NDE techniques, ultrasonic testing, eddy current testing, radiography, and thermography are presented. In order to present the broad subject of NDE modeling for this report, the discussions of modeling research and software packages are limited in scope; however, numerous references are provided in each section for further study by the reader. Given the inherent depth and importance of the field, special emphasis is given to ultrasonic NDE. Discussions are presented on the generation of ultrasound, wave propagation in elastic solids, scattering from cracks, and waves in guides and at interfaces.

  20. Highlights of NASA's Role In Developing State-Of-The-Art Nondestructive Evaluation For Composites

    NASA Technical Reports Server (NTRS)

    Madaras, Eric

    2001-01-01

    Since the 1970's, when the promise of composites was being pursued for aeronautics applications, NASA has had programs that addressed the development of NDE (NonDestructive Evaluation) methods for composites. These efforts included both microscopic and macroscopic NDE. At the microscopic level, NDE investigations interrogated composites at the submicron to micron level to understand a composite's microstructure. A novel microfocus CT system was developed as well as the science underlying applications of acoustic microscopy to a composite's component material properties. On the macroscopic scale NDE techniques were'developed that advanced the capabilities to be faster and more quantitative. Techniques such as stiffness imaging, ultrasonic arrays, laser based ultrasound, advanced acoustic emission, thermography, and novel health monitoring systems were researched. Underlying these methods has been a strong modeling capability that has aided in method development.

  1. Use of an ultrasonic-acoustic technique for nondestructive evaluation of fiber composite strength

    NASA Technical Reports Server (NTRS)

    Vary, A.; Bowles, K. J.

    1978-01-01

    Details of the method used to measure the stress wave factor are described. Frequency spectra of the stress waves are analyzed in order to clarify the nature of the wave phenomena involved. The stress wave factor was measured with simple contact probes requiring only one-side access to a part. This is beneficial in nondestructive evaluations because the waves can run parallel to fiber directions and thus measure material properties in directions assumed by actual loads. The technique can be applied where conventional through transmission techniques are impractical or where more quantitative data are required. The stress wave factor was measured for a series of graphite/polyimide composite panels, and results obtained are compared with through transmission immersion ultrasonic scans.

  2. Overview of space propulsion systems for identifying nondestructive evaluation and health monitoring opportunities

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    1991-01-01

    The next generation of space propulsion systems will be designed to incorporate advanced health monitoring and nondestructive inspection capabilities. As a guide to help the nondestructive evaluation (NDE) community impact the development of these space propulsion systems, several questions should be addressed. An overview of background and current information on space propulsion systems at both the programmatic and technical levels is provided. A framework is given that will assist the NDE community in addressing key questions raised during the 2 to 5 April 1990 meeting of the Joint Army-Navy-NASA-Air Force (JANNAF) Nondestructive Evaluation Subcommittee (NDES).

  3. Nondestructive Evaluation and Monitoring Results from COPV Accelerated Stress Rupture Testing

    NASA Astrophysics Data System (ADS)

    Saulsberry, Regor L.; Greene, Nathanael J.; Banks, Curtis E.; Madaras, Eric I.; Waller, Jess M.; Forth, Scott C.; Russell, Rick W.

    2010-09-01

    To project objective is to develop and demonstrate nondestructive evaluation(NDE) techniques capable of assessing stress rupture related strength degradation for carbon composite pressure vessels, either in a structural health monitoring(SHM) or periodic inspection mode.

  4. Nondestructive Evaluation for the Space Shuttle's Wing Leading Edge

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I.; Winfree, William P.; Prosser, William H.; Wincheski, Russell A.; Cramer, K. Elliot

    2005-01-01

    The loss of the Space Shuttle Columbia highlighted concerns about the integrity of the Shuttle's thermal protection system, which includes Reinforced Carbon-Carbon (RCC) on the leading edge. This led NASA to investigate nondestructive evaluation (NDE) methods for certifying the integrity of the Shuttle's wing leading edge. That investigation was performed simultaneously with a large study conducted to understand the impact damage caused by errant debris. Among the many advanced NDE methods investigated for applicability to the RCC material, advanced digital radiography, high resolution computed tomography, thermography, ultrasound, acoustic emission and eddy current systems have demonstrated the maturity and success for application to the Shuttle RCC panels. For the purposes of evaluating the RCC panels while they are installed on the orbiters, thermographic detection incorporating principal component analysis (PCA) and eddy current array scanning systems demonstrated the ability to measure the RCC panels from one side only and to detect several flaw types of concern. These systems were field tested at Kennedy Space Center (KSC) and at several locations where impact testing was being conducted. Another advanced method that NASA has been investigating is an automated acoustic based detection system. Such a system would be based in part on methods developed over the years for acoustic emission testing. Impact sensing has been demonstrated through numerous impact tests on both reinforced carbon-carbon (RCC) leading edge materials as well as Shuttle tile materials on representative aluminum wing structures. A variety of impact materials and conditions have been evaluated including foam, ice, and ablator materials at ascent velocities as well as simulated hypervelocity micrometeoroid and orbital debris impacts. These tests have successfully demonstrated the capability to detect and localize impact events on Shuttle's wing structures. A first generation impact sensing system has been designed for the next Shuttle flight and is undergoing final evaluation for deployment on the Shuttle's first return to flight. This system will employ wireless accelerometer sensors that were qualified for other applications on previous Shuttle flights. These sensors will be deployed on the wing's leading edge to detect impacts on the RCC leading edge panels. The application of these methods will help to insure the continued integrity of the Shuttle wing's leading edge system as the Shuttle flights resume and until their retirement.

  5. Technologies for Nondestructive Evaluation of Surfaces and Thin Coatings

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The effort included in this project included several related activities encompassing basic understanding, technological development, customer identification and commercial transfer of several methodologies for nondestructive evaluation of surfaces and thin surface coatings. Consistent with the academic environment, students were involved in the effort working with established investigators to further their training, provide a nucleus of experienced practitioners in the new technologies during their industrial introduction, and utilize their talents for project goals. As will be seen in various portions of the report, some of the effort has led to commercialization. This process has spawned other efforts related to this project which are supported from outside sources. These activities are occupying the efforts of some of the people who were previously supported within this grant and its predecessors. The most advanced of the supported technologies is thermography, for which the previous joint efforts of the investigators and NASA researchers have developed several techniques for extending the utility of straight thermographic inspection by producing methods of interpretation and analysis accessible to automatic image processing with computer data analysis. The effort reported for this technology has been to introduce the techniques to new user communities, who are then be able to add to the effective uses of existing products with only slight development work. In a related development, analysis of a thermal measurement situation in past efforts led to a new insight into the behavior of simple temperature probes. This insight, previously reported to the narrow community in which the particular measurement was made, was reported to the community of generic temperature measurement experts this year. In addition to the propagation of mature thermographic techniques, the development of a thermoelastic imaging system has been an important related development. Part of the work carried out in the effort reported here has been to prepare reports introducing the newly commercially available thermoelastic measurements to the appropriate user communities.

  6. Rapid Prototyping Integrated With Nondestructive Evaluation and Finite Element Analysis

    NASA Technical Reports Server (NTRS)

    Abdul-Aziz, Ali; Baaklini, George Y.

    2001-01-01

    Most reverse engineering approaches involve imaging or digitizing an object then creating a computerized reconstruction that can be integrated, in three dimensions, into a particular design environment. Rapid prototyping (RP) refers to the practical ability to build high-quality physical prototypes directly from computer aided design (CAD) files. Using rapid prototyping, full-scale models or patterns can be built using a variety of materials in a fraction of the time required by more traditional prototyping techniques (refs. 1 and 2). Many software packages have been developed and are being designed to tackle the reverse engineering and rapid prototyping issues just mentioned. For example, image processing and three-dimensional reconstruction visualization software such as Velocity2 (ref. 3) are being used to carry out the construction process of three-dimensional volume models and the subsequent generation of a stereolithography file that is suitable for CAD applications. Producing three-dimensional models of objects from computed tomography (CT) scans is becoming a valuable nondestructive evaluation methodology (ref. 4). Real components can be rendered and subjected to temperature and stress tests using structural engineering software codes. For this to be achieved, accurate high-resolution images have to be obtained via CT scans and then processed, converted into a traditional file format, and translated into finite element models. Prototyping a three-dimensional volume of a composite structure by reading in a series of two-dimensional images generated via CT and by using and integrating commercial software (e.g. Velocity2, MSC/PATRAN (ref. 5), and Hypermesh (ref. 6)) is being applied successfully at the NASA Glenn Research Center. The building process from structural modeling to the analysis level is outlined in reference 7. Subsequently, a stress analysis of a composite cooling panel under combined thermomechanical loading conditions was performed to validate this process.

  7. a University Course on the Physical Principles of Ultrasound Nondestructive Evaluation

    NASA Astrophysics Data System (ADS)

    Genis, Vladimir

    2009-03-01

    The ultrasound nondestructive evaluation (NDE) of materials course was offered to Applied Engineering Technology (AET) students at Drexel University for last two years. The main objective of this three-credit (thirty-hour) course is to introduce students to physical principles of ultrasound measurements and to demonstrate the basic principles of ultrasound nondestructive evaluation of materials by combining hands-on laboratory experience with lectures. The work in the laboratory enhances the fundamentals taught in the classroom sessions.

  8. Nondestructive evaluation of composite materials by electrical resistance measurement

    NASA Astrophysics Data System (ADS)

    Mei, Zhen

    This dissertation investigates electrical resistance measurement for nondestructive evaluation of carbon fiber (CF) reinforced polymer matrix composites. The method involves measuring the DC electrical resistance in either the longitudinal or through thickness direction. The thermal history and thermal properties of thermoplastic/CF composites were studied by longitudinal and through-thickness resistance measurements. The resistance results were consistent with differential scanning calorimetry (DSC) and thermomechanical analysis (TMA) results. The resistance measurements gave more information on the melting of the polymer matrix than TMA. They were more sensitive to the glass transition of the polymer matrix than DSC. The through-thickness resistance decreased as autohesion progressed. The activation energy of autohesion was 21.2 kJ/mol for both nylon-6 and polyphenylene sulfide (PPS)/CF composites. Adhesive bonding and debonding were monitored in real-time by measurement of the through-thickness resistance between the adherends in an adhesive joint during heating and subsequent cooling. Debonding occurred during cooling when the pressure or temperature during prior bonding was not sufficiently high. A long heating time below the melting temperature (T m) was found to be detrimental to subsequent PPS adhesive joint development above Tm, due to curing reactions below Tm and consequent reduced mass flow response above Tm. A high heating rate (small heating time) enhanced the bonding more than a high pressure. The longitudinal resistance measurement was used to investigate the effects of temperature and stress on the interface between a concrete substrate and its epoxy/CF composite retrofit. The resistance of the retrofit was increased by bond degradation, whether the degradation was due to heat or stress. The degradation was reversible. Irreversible disturbance in the fiber arrangement occurred slightly as thermal or load cycling occurred, as indicated by the resistance decreasing cycle by cycle. This dissertation also addresses the use of the electrical resistance method to observe thermal and mechanical damage in real time. A temperature increase caused the interlaminar contact resistance to decrease reversibly within each thermal cycle, while thermal damage caused the resistance to decrease abruptly and irreversibly, due to matrix molecular movement and the consequent increase in the chance of fibers of one lamina touching those of an adjacent lamina. The through-thickness volume resistivity irreversibly and gradually decreased upon mechanical damage, which was probably fiber-matrix debonding. Moreover, it reversibly and abruptly increased upon matrix micro-structural change, which occurred reversibly near the peak stress of a stress cycle.

  9. Nondestructive evaluation of the complex modulus master curve of asphalt concrete specimens

    NASA Astrophysics Data System (ADS)

    Gudmarsson, A.; Ryden, N.; Birgisson, B.

    2013-01-01

    The dynamic Young's modulus of asphalt concrete is directly related to pavement quality and is used in thickness design of pavements. There is a need for a nondestructive laboratory method to evaluate the complex modulus, which can be linked to nondestructive field measurements. This study applies seismic measurements to an asphalt concrete beam where resonant acoustic spectroscopy and optimization of frequency response functions are used to estimate the complex moduli. A good estimation of the master curve is obtained.

  10. Recent advances in nondestructive evaluation made possible by novel uses of video systems

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.; Roth, Don J.

    1990-01-01

    Complex materials are being developed for use in future advanced aerospace systems. High temperature materials have been targeted as a major area of materials development. The development of composites consisting of ceramic matrix and ceramic fibers or whiskers is currently being aggressively pursued internationally. These new advanced materials are difficult and costly to produce; however, their low density and high operating temperature range are needed for the next generation of advanced aerospace systems. These materials represent a challenge to the nondestructive evaluation community. Video imaging techniques not only enhance the nondestructive evaluation, but they are also required for proper evaluation of these advanced materials. Specific research examples are given, highlighting the impact that video systems have had on the nondestructive evaluation of ceramics. An image processing technique for computerized determination of grain and pore size distribution functions from microstructural images is discussed. The uses of video and computer systems for displaying, evaluating, and interpreting ultrasonic image data are presented.

  11. Development of nondestructive evaluation methods for ceramic coatings.

    SciTech Connect

    Ellingson, W. A.; Deemer, C.; Sun, J. G.; Erdman, S.; Muliere, D.; Wheeler, B.

    2002-04-29

    Various nondestructive evaluation (NDE) technologies are being developed to study the use of ceramic coatings on components in the hot-gas path of advanced low-emission gas-fired turbines. The types of ceramic coatings include thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs). TBCs are under development for vanes, blades, and combustor liners to allow hotter gas-path temperatures, and EBCs are under development to reduce environmental damage to high-temperature components made of ceramic matrix composites. The NDE methods will be used to (a) provide data to assess the reliability of new coating application processes, (b) identify defective components that could cause unscheduled outages, (c) track growth rates of defects during component use in engines, and (d) allow rational judgment for replace/repair/re-use decisions regarding components. Advances in TBC application, both electron beam-physical vapor deposition (EB-PVD) and air plasma spraying (APS), are allowing higher temperatures in the hot-gas path. However, as TBCs become ''prime reliant,'' their condition at scheduled or unscheduled outages must be known. NDE methods are under development to assess the condition of the TBC for pre-spall conditions. EB-PVD test samples with up to 70 thermal cycles have been studied by a newly developed method involving polarized laser back-scatter NDE. Results suggest a correlation between the NDE laser data and the TBC/bond-coat topography. This finding is important because several theories directed toward understanding the pre-spall condition suggest that the topography in the thermally grown oxide layer changes significantly as a function of the number of thermal cycles. Tests have also been conducted with this NDE method on APS TBCs. Results suggest that the pre-spall condition is detected for these coatings. One-sided, high-speed thermal imaging also has shown promise for NDE of APS coatings. Testing of SiC/SiC composites for combustor liners has demonstrated that environmental EBCs are required to reduce oxidation-induced recession rates. NDE technologies, primarily one-sided and through-thickness thermal imaging, are under development to detect delaminations and degradation of EBCs. Recent results have demonstrated that NDE thermal image data correctly detected pre-spall regions of a barium-strontium-alumino-silicate coating on melt-infiltrated SiC/SiC. The NDE data were verified with field test data from a combustor liner in a 4.5 MW(e) natural-gas-fired turbine. The shape of the spalled EBC region and the growth of the spalled EBC region after various engine run times were correlated with boroscope image data from field tests. An effort has recently been started to address NDE development for oxide/oxide ceramic composites with an EBC. We will discuss the NDE methods under development for TBCs, recent NDE test results from thermally cycled TBCs, NDE results from EBCs on SiC/SiC, and the new effort directed toward oxide/oxide materials.

  12. Nondestructive evaluation of ceramic matrix composite combustor components.

    SciTech Connect

    Sun, J. G.; Verrilli, M. J.; Stephan, R.; Barnett, T. R.; Ojard, G.

    2002-11-08

    Combustor liners fabricated from a SiC/SiC composite were nondestructively interrogated before and after combustion rig testing. The combustor liners were inspected by X-ray, ultrasonic and thermographic techniques. In addition, mechanical test results were obtained from witness coupons, representing the as-manufactured liners, and from coupons machined from the components after combustion exposure. Thermography indications were found to correlate with reduced material properties obtained after rig testing. Microstructural examination of the SiC/SiC liners revealed the thermography indications to be delaminations and damaged fiber tows.

  13. Nondestructive Evaluation of Ceramic Matrix Composite Combustor Components

    NASA Astrophysics Data System (ADS)

    Sun, J. G.; Verrilli, M. J.; Stephan, R.; Barnett, T. R.; Ojard, G.

    2003-03-01

    Combustor liners fabricated from a SiC/SiC composite were nondestructively interrogated before and after combustion rig testing by X-ray, ultrasonic and thermographic techniques. In addition, mechanical test results were obtained from witness coupons, representing the as-manufactured liners, and from coupons machined from the components after combustion exposure. Thermography indications were found to correlate with reduced material properties obtained after rig testing. The thermography indications in the SiC/SiC liners were delaminations and damaged fiber tows, as determined through microstructural examinations.

  14. Nondestructive Evaluation of Ceramic Matrix Composite Combustor Components

    NASA Technical Reports Server (NTRS)

    Sun, J. G.; Verrilli, M. J.; Stephan, R.; Barnett, T. R.; Ojard, G.

    2003-01-01

    Combustor liners fabricated from a SiC/SiC composite were nondestructively interrogated before and after combustion rig testing by X-ray, ultrasonic and thermographic techniques. In addition, mechanical test results were obtained from witness coupons, representing the as-manufactured liners, and from coupons machined from the components after combustion exposure. Thermography indications were found to correlate with reduced material properties obtained after rig testing. The thermography indications in the SiC/SiC liners were delaminations and damaged fiber tows, as determined through microstructural examinations. [copyright] 2003 American Institute of Physics

  15. Nondestructive Evaluation of Ceramic Matrix Composite Combustor Components

    NASA Technical Reports Server (NTRS)

    Sun, Jiangang G.; Verrilli, Michael J.; Stephan, Robert R.; Barnett, Terry R.; Ojard, Greg C.

    2003-01-01

    Combustor liners fabricated from a SiC/SiC composite (silicon carbide fibers in a silicon carbide matrix) were nondestructively interrogated before and after combustion rig testing by x-ray, ultrasonic, and thermographic techniques. In addition, mechanical test results were obtained from witness coupons, representing the as-manufactured liners, and from coupons machined from the components after combustion exposure. Thermography indications correlated with reduced material properties obtained after rig testing. The thermography indications in the SiC/SiC liners were delaminations and damaged fiber tows, as determined through microstructural examinations.

  16. Quantitative evaluation of Alzheimer's disease

    NASA Astrophysics Data System (ADS)

    Duchesne, S.; Frisoni, G. B.

    2009-02-01

    We propose a single, quantitative metric called the disease evaluation factor (DEF) and assess its efficiency at estimating disease burden in normal, control subjects (CTRL) and probable Alzheimer's disease (AD) patients. The study group consisted in 75 patients with a diagnosis of probable AD and 75 age-matched normal CTRL without neurological or neuropsychological deficit. We calculated a reference eigenspace of MRI appearance from reference data, in which our CTRL and probable AD subjects were projected. We then calculated the multi-dimensional hyperplane separating the CTRL and probable AD groups. The DEF was estimated via a multidimensional weighted distance of eigencoordinates for a given subject and the CTRL group mean, along salient principal components forming the separating hyperplane. We used quantile plots, Kolmogorov-Smirnov and χ2 tests to compare the DEF values and test that their distribution was normal. We used a linear discriminant test to separate CTRL from probable AD based on the DEF factor, and reached an accuracy of 87%. A quantitative biomarker in AD would act as an important surrogate marker of disease status and progression.

  17. Nondestructive evaluation of repairs on aircraft composite structures

    NASA Astrophysics Data System (ADS)

    Hsu, David K.; Barnard, Daniel J.; Peters, John J.

    2001-08-01

    Composite sandwiches have been used widely in flight controls of aircraft for many years; solid laminates have also begun to appear in primary structures such as the empennage. In their normal service life, composite parts may suffer damages and require repair and post-repair inspection. Nondestructive inspection is also needed for many of the rebuilt and refurbished parts in the maintenance, repair and overhaul industry. This paper describes the development of fieldable nondestructive inspection methods and instruments for composite structures and their repairs. For composite sandwiches the method developed is an instrumented tap test using the Computer Aided Tap Test (CATT) system. For repairs in solid laminates, the method used is ultrasonic pulse-echo C-scan using the Dripless Bubbler. The CATT system maps out the repaired region and produces an image of the local stiffness. Such images reveal voids and unbonds in a repair as areas of anomalously low stiffness; it also maps out areas of increased stiffness due to core potting and splicing. A number of examples of composite repairs inspected with the CATT system will be described. For engineered flaws in solid laminate repair panels from Boeing, scan images obtained with the Dripless Bubbler as a function of depth will be shown.

  18. Quantitative evaluation of dermatological antiseptics.

    PubMed

    Leitch, C S; Leitch, A E; Tidman, M J

    2015-12-01

    Topical antiseptics are frequently used in dermatological management, yet evidence for the efficacy of traditional generic formulations is often largely anecdotal. We tested the in vitro bactericidal activity of four commonly used topical antiseptics against Staphylococcus aureus, using a modified version of the European Standard EN 1276, a quantitative suspension test for evaluation of the bactericidal activity of chemical disinfectants and antiseptics. To meet the standard for antiseptic effectiveness of EN 1276, at least a 5 log10 reduction in bacterial count within 5 minutes of exposure is required. While 1% benzalkonium chloride and 6% hydrogen peroxide both achieved a 5 log10 reduction in S. aureus count, neither 2% aqueous eosin nor 1 : 10 000 potassium permanganate showed significant bactericidal activity compared with control at exposure periods of up to 1 h. Aqueous eosin and potassium permanganate may have desirable astringent properties, but these results suggest they lack effective antiseptic activity, at least against S. aureus. PMID:26456933

  19. Nondestructive 3D confocal laser imaging with deconvolution of seven whole stardust tracks with complementary XRF and quantitative analysis

    SciTech Connect

    Greenberg, M.; Ebel, D.S.

    2009-03-19

    We present a nondestructive 3D system for analysis of whole Stardust tracks, using a combination of Laser Confocal Scanning Microscopy and synchrotron XRF. 3D deconvolution is used for optical corrections, and results of quantitative analyses of several tracks are presented. The Stardust mission to comet Wild 2 trapped many cometary and ISM particles in aerogel, leaving behind 'tracks' of melted silica aerogel on both sides of the collector. Collected particles and their tracks range in size from submicron to millimeter scale. Interstellar dust collected on the obverse of the aerogel collector is thought to have an average track length of {approx}15 {micro}m. It has been our goal to perform a total non-destructive 3D textural and XRF chemical analysis on both types of tracks. To that end, we use a combination of Laser Confocal Scanning Microscopy (LCSM) and X Ray Florescence (XRF) spectrometry. Utilized properly, the combination of 3D optical data and chemical data provides total nondestructive characterization of full tracks, prior to flattening or other destructive analysis methods. Our LCSM techniques allow imaging at 0.075 {micro}m/pixel, without the use of oil-based lenses. A full textural analysis on track No.82 is presented here as well as analysis of 6 additional tracks contained within 3 keystones (No.128, No.129 and No.140). We present a method of removing the axial distortion inherent in LCSM images, by means of a computational 3D Deconvolution algorithm, and present some preliminary experiments with computed point spread functions. The combination of 3D LCSM data and XRF data provides invaluable information, while preserving the integrity of the samples for further analysis. It is imperative that these samples, the first extraterrestrial solids returned since the Apollo era, be fully mapped nondestructively in 3D, to preserve the maximum amount of information prior to other, destructive analysis.

  20. Time-resolved fluorescence spectroscopy and ultrasound backscatter microscopy for nondestructive evaluation of vascular grafts

    PubMed Central

    Fatakdawala, Hussain; Griffiths, Leigh G.; Humphrey, Sterling; Marcu, Laura

    2014-01-01

    Abstract. Quantitative and qualitative evaluations of structure and composition are important in monitoring development of engineered vascular tissue both in vitro and in vivo. Destructive techniques are an obstacle for performing time-lapse analyses from a single sample or animal. This study demonstrates the ability of time-resolved fluorescence spectroscopy (TRFS) and ultrasound backscatter microscopy (UBM), as nondestructive and synergistic techniques, for compositional and morphological analyses of tissue grafts, respectively. UBM images and integrated backscatter coefficients demonstrate the ability to visualize and quantify postimplantation changes in vascular graft biomaterials such as loss of the external elastic lamina and intimal/medial thickening over the grafted region as well as graft integration with the surrounding tissue. TRFS results show significant changes in spectra, average lifetime, and fluorescence decay parameters owing to changes in collagen, elastin, and cellular content between normal and grafted tissue regions. These results lay the foundation for the application of a catheter-based technique for in vivo evaluation of vascular grafts using TRFS and UBM. PMID:25147960

  1. Nondestructive evaluation of thermal spray cathodic protection anodes

    SciTech Connect

    Covino, B.S., Jr.; Russell, J.H.; Bullard, S.J.; Holcomb, G.R.; Cramer, S.D.

    2000-03-01

    The aging of thermal spray (TS) cathodic protection (CP) anodes is usually characterized by the amount of current passing through the anode-concrete interface. This charge, also called electrochemical age, can be correlated to bond strength and eventual failure of TS Zn anodes. Several non-destructive techniques were subsequently applied to aged thermal spray anodes to determine if other property measurements would correlate to electrochemical age and thus to service life. The techniques considered are the circuit resistance of impressed current anodes, the AC resistivity between the rebar and the anode, and the surface resistivity of the TS anodes. All three techniques gave a good correlation of measured property to electrochemical age. Surface resistivity can also be used to calculate the thickness of anode remaining.

  2. Nondestructive evaluation of a ceramic matrix composite material

    NASA Technical Reports Server (NTRS)

    Grosskopf, Paul P.; Duke, John C., Jr.

    1992-01-01

    Monolithic ceramic materials have proven their usefulness in many applications, yet, their potential for critical structural applications is limited because of their sensitivity to small imperfections. To overcome this extreme sensitivity to small imperfections, ceramic matrix composite materials have been developed that have the ability to withstand some distributed damage. A borosilicate glass reinforced with several layers of silicon-carbide fiber mat has been studied. Four-point flexure and tension tests were performed not only to determine some of the material properties, but also to initiate a controlled amount of damage within each specimen. Acousto-ultrasonic (AU) measurements were performed periodically during mechanical testing. This paper will compare the AU results to the mechanical test results and data from other nondestructive methods including acoustic emission monitoring and X-ray radiography. It was found that the AU measurements were sensitive to the damage that had developed within the material.

  3. Optimization of ISOCS Parameters for Quantitative Non-Destructive Analysis of Uranium in Bulk Form

    NASA Astrophysics Data System (ADS)

    Kutniy, D.; Vanzha, S.; Mikhaylov, V.; Belkin, F.

    2011-12-01

    Quantitative calculation of the isotopic masses of fissionable U and Pu is important for forensic analysis of nuclear materials. γ-spectrometry is the most commonly applied tool for qualitative detection and analysis of key radionuclides in nuclear materials. Relative isotopic measurement of U and Pu may be obtained from γ-spectra through application of special software such as MGAU (Multi-Group Analysis for Uranium, LLNL) or FRAM (Fixed-Energy Response Function Analysis with Multiple Efficiency, LANL). If the concentration of U/Pu in the matrix is unknown, however, isotopic masses cannot be calculated. At present, active neutron interrogation is the only practical alternative for non-destructive quantification of fissionable isotopes of U and Pu. An active well coincidence counter (AWCC), an alternative for analyses of uranium materials, has the following disadvantages: 1) The detection of small quantities (≤100 g) of 235U is not possible in many models; 2) Representative standards that capture the geometry, density and chemical composition of the analyzed unknown are required for precise analysis; and 3) Specimen size is severely restricted by the size of the measuring chamber. These problems may be addressed using modified γ-spectrometry techniques based on a coaxial HPGe-detector and ISOCS software (In Situ Object Counting System software, Canberra). We present data testing a new gamma-spectrometry method uniting actinide detection with commonly utilized software, modified for application in determining the masses of the fissionable isotopes in unknown samples of nuclear materials. The ISOCS software, widely used in radiation monitoring, calculates the detector efficiency curve in a specified geometry and range of photon energies. In describing the geometry of the source-detector, it is necessary to clearly describe the distance between the source and the detector, the material and the thickness of the walls of the container, as well as material, density and chemical composition of the matrix of the specimen. Obviously, not all parameters can be characterized when measuring samples of unknown composition or uranium in bulk form. Because of this, and especially for uranium materials, the IAEA developed an ISOCS optimization procedure. The target values for the optimization are Μmatrixfixed, the matrix mass determined by weighing with a known mass container, and Εfixed, the 235U enrichment, determined by MGAU. Target values are fitted by varying the matrix density (ρ), and the concentration of uranium in the matrix of the unknown (w). For each (ρi, wi), an efficiency curve is generated, and the masses of uranium isotopes, Μ235Ui and Μ238Ui, determined using spectral activity data and known specific activities for U. Finally, fitted parameters are obtained for Μmatrixi = Μmatrixfixed ± 1σ, Εi = Εfixed ± 1σ, as well as important parameters (ρi, wi, Μ235Ui, Μ238Ui, ΜUi). We examined multiple forms of uranium (powdered, pressed, and scrap UO2 and U3O8) to test this method for its utility in accurately identifying the mass and enrichment of uranium materials, and will present the results of this research.

  4. Nondestructive evaluation of composite materials by pulsed time domain methods in imbedded optical fibers

    NASA Technical Reports Server (NTRS)

    Claus, R. O.; Bennett, K. D.; Jackson, B. S.

    1986-01-01

    The application of fiber-optical time domain reflectometry (OTDR) to nondestructive quantitative measurements of distributed internal strain in graphite-epoxy composites, using optical fiber waveguides imbedded between plies, is discussed. The basic OTDR measurement system is described, together with the methods used to imbed optical fibers within composites. Measurement results, system limitations, and the effect of the imbedded fiber on the integrity of the host composite material are considered.

  5. A study on the quantitative evaluation of skin barrier function

    NASA Astrophysics Data System (ADS)

    Maruyama, Tomomi; Kabetani, Yasuhiro; Kido, Michiko; Yamada, Kenji; Oikaze, Hirotoshi; Takechi, Yohei; Furuta, Tomotaka; Ishii, Shoichi; Katayama, Haruna; Jeong, Hieyong; Ohno, Yuko

    2015-03-01

    We propose a quantitative evaluation method of skin barrier function using Optical Coherence Microscopy system (OCM system) with coherency of near-infrared light. There are a lot of skin problems such as itching, irritation and so on. It has been recognized skin problems are caused by impairment of skin barrier function, which prevents damage from various external stimuli and loss of water. To evaluate skin barrier function, it is a common strategy that they observe skin surface and ask patients about their skin condition. The methods are subjective judgements and they are influenced by difference of experience of persons. Furthermore, microscopy has been used to observe inner structure of the skin in detail, and in vitro measurements like microscopy requires tissue sampling. On the other hand, it is necessary to assess objectively skin barrier function by quantitative evaluation method. In addition, non-invasive and nondestructive measuring method and examination changes over time are needed. Therefore, in vivo measurements are crucial for evaluating skin barrier function. In this study, we evaluate changes of stratum corneum structure which is important for evaluating skin barrier function by comparing water-penetrated skin with normal skin using a system with coherency of near-infrared light. Proposed method can obtain in vivo 3D images of inner structure of body tissue, which is non-invasive and non-destructive measuring method. We formulate changes of skin ultrastructure after water penetration. Finally, we evaluate the limit of performance of the OCM system in this work in order to discuss how to improve the OCM system.

  6. A knowledge-based shell for selecting a nondestructive evaluation technique

    SciTech Connect

    Roberge, P.R.

    1995-02-01

    The complexity of planning a nondestructive evaluation (NDE) program or an inspection schedule for specific problems and available NDE techniques can be drastically reduced by the creation of a knowledge based system that would balance the advantages and limitations of each technique for specific problems. Such a system could incorporate the fundamental knowledge derived from failure analysis and cover topics such as materials vs. defect size and type, probability of failure, and basic reliability information. In order to efficiently organize knowledge of materials degradation, the parameters that control various forms of failure must first be rationalized in a general framework. This framework and their factors would then constitute a quantitative and easily programmable description of the independent variables controlling the intensity of a failure. This article describes such a framework, which could guide the general selection of NDE for materials failure with a particular emphasis on corrosion related failures. The framework architecture itself was constructed using an object-oriented methodology for maximum flexibility because it was anticipated that the materials parameters could easily be described as multidimensional objects.

  7. Ultrasound nondestructive evaluation (NDE) imaging with transducer arrays and adaptive processing.

    PubMed

    Li, Minghui; Hayward, Gordon

    2012-01-01

    This paper addresses the challenging problem of ultrasonic non-destructive evaluation (NDE) imaging with adaptive transducer arrays. In NDE applications, most materials like concrete, stainless steel and carbon-reinforced composites used extensively in industries and civil engineering exhibit heterogeneous internal structure. When inspected using ultrasound, the signals from defects are significantly corrupted by the echoes form randomly distributed scatterers, even defects that are much larger than these random reflectors are difficult to detect with the conventional delay-and-sum operation. We propose to apply adaptive beamforming to the received data samples to reduce the interference and clutter noise. Beamforming is to manipulate the array beam pattern by appropriately weighting the per-element delayed data samples prior to summing them. The adaptive weights are computed from the statistical analysis of the data samples. This delay-weight-and-sum process can be explained as applying a lateral spatial filter to the signals across the probe aperture. Simulations show that the clutter noise is reduced by more than 30 dB and the lateral resolution is enhanced simultaneously when adaptive beamforming is applied. In experiments inspecting a steel block with side-drilled holes, good quantitative agreement with simulation results is demonstrated. PMID:22368457

  8. Low velocity impact testing and nondestructive evaluation of transparent materials

    SciTech Connect

    Brennan, R. E.; Green, W. H.

    2011-06-23

    Advanced transparent materials are used in protective systems for enhancing the survivability of ground vehicles, air vehicles, and personnel in applications such as face shields, riot gear, and vehicle windows. Low velocity impact damage can limit visibility and compromise the structural integrity of a transparent system, increasing the likelihood of further damage or penetration from a high velocity impact strike. For this reason, it is critical to determine damage tolerance levels of transparent systems to indicate whether or not a component should be replaced. In this study, transparent laminate systems will be tested by comparing baseline conditions to experimentally controlled damage states. Destructive testing including air gun and sphere impact testing will be used to replicate low velocity impacts in the field. Characterization of the damaged state will include basic visual inspection as well as nondestructive techniques including cross-polarization, x-ray, and ultrasound. The combination of destructive testing and characterization of the resulting damage can help to establish a damage acceptance criterion for materials used in protective systems.

  9. Forensic Examination Using a Nondestructive Evaluation Method for Surface Metrology

    NASA Astrophysics Data System (ADS)

    Eisenmann, David J.; Chumbley, L. Scott

    2009-03-01

    The objective of this paper is to describe the use of a new technique of optical profilometry in a nondestructive, non-contact fashion for the comparison of two metallic surfaces, one hard and one soft. When brought in contact with one another, the harder material (i.e. the tool) will impress its surface roughness onto the softer. It is understood that the resulting set of impressions left from a tool tip act in a manner similar to a photographic negative, in that it leaves a reverse, or negative impression on the surface of a plate. If properly inverted and reversed, measurements from the softer material should be identical to the harder indenting object with regard to surface texture and roughness. This assumption is inherent in the area of forensics, where bullets, cartridge cases, and toolmarked surfaces from crime scenes are compared to similar marks made under controlled conditions in the forensic laboratory. This paper will examine the methodology used to compare two surfaces for similarities and dissimilarities, and comment on the applicability of this technique to other studies.

  10. Estimate of accuracy requirements for nondestructive evaluation of materials properties

    NASA Astrophysics Data System (ADS)

    Gamble, Ronald C.; Taylor, Tom

    1995-05-01

    Research literature documents several nondestructive (NDE) techniques for measuring material properties such as residual stress, embrittlement and fatigue damage. Reports in peer reviewed publications thoroughly describe the experimental measurement techniques and provide a comparison between expected analytical results and experimental measurements. A simple rationale for estimating the required accuracy of NDE to measure residual stress shows that residual stress measurements are acceptable if accurate to within plus or minus 10%. An analysis of the effect of neutron fluence on fracture toughness shows a more complex relationship. At temperature and fluence conditions corresponding to low toughness; fracture toughness is insensitive to fluence and high accuracy for NDE embrittlement is not required. However, for conditions associated with high toughness, changes in fluence have significant effect. Calculations indicate that NDE measurements of irradiation effects should have an accuracy of approximately plus or minus 15% to correspond to a plus or minus 10% change in KIC over the toughness range from about 40 to 100 ksi(root)in.

  11. Ultrasonic infrared thermal wave nondestructive evaluation for crack detection of several aerospace materials

    NASA Astrophysics Data System (ADS)

    Xu, Weichao; Shen, Jingling; Zhang, Cunlin; Tao, Ning; Feng, Lichun

    2008-03-01

    The applications of ultrasonic infrared thermal wave nondestructive evaluation for crack detection of several materials, which often used in aviation alloy. For instance, steel and carbon fiber. It is difficult to test cracks interfacial or vertical with structure's surface by the traditional nondestructive testing methods. Ultrasonic infrared thermal wave nondestructive testing technology uses high-power and low-frequency ultrasonic as heat source to excite the sample and an infrared video camera as a detector to detect the surface temperature. The ultrasonic emitter launch pulses of ultrasonic into the skin of the sample, which causes the crack interfaces to rub and dissipate energy as heat, and then caused local increase in temperature at one of the specimen surfaces. The infrared camera images the returning thermal wave reflections from subsurface cracks. A computer collects and processes the thermal images according to different properties of samples to get the satisfied effect. In this paper, a steel plate with fatigue crack we designed and a juncture of carbon fiber composite that has been used in a space probe were tested and get satisfying results. The ultrasonic infrared thermal wave nondestructive detection is fast, sensitive for cracks, especially cracks that vertical with structure's surface. It is significative for nondestructive testing in manufacture produce and application of aviation, cosmography and optoelectronics.

  12. Tele-shearography for nondestructive evaluation (NDE) of aircraft/composite panels: an analysis

    NASA Astrophysics Data System (ADS)

    Ng, Chee Keong; Murukeshan, Vadakke M.; Ong, Seng L.; Wong, Brian S.; Asundi, Anand K.

    2001-10-01

    Tele-shearographic system based on bulk optics shearing and optical fiber based illumination have been used for the Non-Destructive Testing (NDT)of aircraft/composite laminates. This paper describes the application of this system and a detailed experimental analysis to assess defects in Carbon Fiber Reinforced Plastic (CFRP) composite laminates by analyzing the fringe patterns. CFRP laminates and honeycomb panels have been studied using the this system in various optical configurations. This technique provides the full-field, non-contact method for Non-Destructive Evaluation (NDE) of composite specimens. A Comparative study between digital shearography and other NDTechniques are also discussed in this paper.

  13. Nondestructive evaluation of internal maturity of tomatoes using spatially offset Raman spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This research explored the use of spatially offset Raman spectroscopy (SORS) for nondestructive evaluation of internal maturity of tomatoes. A Raman spectroscopy system using a 785 nm laser was developed to collect spatially-offset spectra in the wavenumber range of 200 – 2500. The SORS measuremen...

  14. Acousto-ultrasonic nondestructive evaluation of materials using laser beam generation and detection

    NASA Technical Reports Server (NTRS)

    Huber, Robert D.; Green, Robert E., Jr.; Vary, Alex; Kautz, Harold

    1990-01-01

    Presented in viewgraph format, the possibility of using laser generation and detection of ultrasound to replace piezoelectric transducers for the acousto-ultrasonic technique is advanced. The advantages and disadvantages of laser acousto-ultrasonics are outlined. Laser acousto-ultrasonics complements standard piezoelectric acousto-ultrasonics and offers non-contact nondestructive evaluation.

  15. Nondestructive evaluation: A survey of NASA contributions, chapter 1, Chapter 11, cover page, acknowledgements, and contents

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A survey of nondestructive evaluation (NDE) technology, which is discussed in terms of popular demands for a greater degree of quality, reliability, and safety in industrial products, is presented as an overview of the NDE field to serve the needs of middle management. Three NDE methods are presented: acoustic emission, the use of coherent (laser)light, and ultrasonic holography.

  16. Assessing modulus of elasticity of wood-fiber cement (WFC) sheets using nondestructive evaluation (NDE).

    PubMed

    Teixeira, D E; Moslemi, A

    2001-09-01

    This study evaluates whether the mechanical properties of modulus of rupture (MOR) and modulus of elasticity (MOE) of wood-fiber cement (WFC) sheets are correlated with the nondestructive parameters of stress wave velocity and density of the material. Longitudinal stress wave technique was used to evaluate WFC nondestructively using a total of 117 specimens (measuring each 241 x 51 mm) obtained from 39 WFC sheets. The aim was to establish the correlation between dynamic versus static MOE of the material for predicting the actual mechanical property. Even though short dimension specimens were used, results obtained were encouraging. A correlation coefficient (R) of 0.828 was found when the static MOE of the material was used as a function of nondestructive parameters. A multivariate linear regression analysis using the specimen's density, wave velocity, and dynamic MOE provided the strongest correlation to the static MOE. The correlation observed for MOR as a function of static MOE is within the normal range obtained for wood composites. A nondestructive evaluation (NDE) using full size WFC sheets is recommended and can probably improve the relationship between the static and the predicted MOE. PMID:11480928

  17. Nondestructive spectroscopic and imaging techniques for quality evaluation and assessment of fish and fish products.

    PubMed

    He, Hong-Ju; Wu, Di; Sun, Da-Wen

    2015-01-01

    Nowadays, people have increasingly realized the importance of acquiring high quality and nutritional values of fish and fish products in their daily diet. Quality evaluation and assessment are always expected and conducted by using rapid and nondestructive methods in order to satisfy both producers and consumers. During the past two decades, spectroscopic and imaging techniques have been developed to nondestructively estimate and measure quality attributes of fish and fish products. Among these noninvasive methods, visible/near-infrared (VIS/NIR) spectroscopy, computer/machine vision, and hyperspectral imaging have been regarded as powerful and effective analytical tools for fish quality analysis and control. VIS/NIR spectroscopy has been widely applied to determine intrinsic quality characteristics of fish samples, such as moisture, protein, fat, and salt. Computer/machine vision on the other hand mainly focuses on the estimation of external features like color, weight, size, and surface defects. Recently, by incorporating both spectroscopy and imaging techniques in one system, hyperspectral imaging cannot only measure the contents of different quality attributes simultaneously, but also obtain the spatial distribution of such attributes when the quality of fish samples are evaluated and measured. This paper systematically reviews the research advances of these three nondestructive optical techniques in the application of fish quality evaluation and determination and discuss future trends in the developments of nondestructive technologies for further quality characterization in fish and fish products. PMID:24915393

  18. Assessing the reliability of nondestructive evaluation methods for damage characterization

    NASA Astrophysics Data System (ADS)

    Aldrin, John C.; Annis, Charles; Sabbagh, Harold A.; Knopp, Jeremy S.; Lindgren, Eric A.

    2014-02-01

    A comprehensive approach to NDE characterization error evaluation is presented that follows the framework of the `ahat-versus-a' model evaluation process for probability of detection (POD) assessment. Before characterization error model building is performed, an intermediate step must evaluate the presence and frequency of several possible classes of poor characterization results. A case study is introduced based on the estimation the length, depth and width of surface breaking cracks using bolt hole eddy current (BHEC) NDE. This study highlights the importance of engineering and statistical expertise in the model-building process to ensure all key effects and possible interactions are addressed.

  19. Nondestructive evaluation of metal and composite targets using an infrared line-scanning technique

    NASA Astrophysics Data System (ADS)

    Smith, Christopher; Rowley, Matthew; Dvonch, Curt; Fulton, Mary

    2005-03-01

    A thermal, non-destructive evaluation (NDE) technique has been employed by ThermTech Services, Inc. in cooperation with NASA Langley Research Center that allows for quantitative measurements of wall thickness in steam boilers. By determining the thickness of the walls, one can easily determine how much thinning has occurred due to corrosion. This type of NDE can be applied to the inspection of wings and fuselages on aircraft and spaceflight vehicles including the shuttle. The NDE technique employs the linear movement of a heat source (lamp) and an infrared imager that is situated at a fixed distance behind the heat source. The instruments are aligned on a platform that moves up and down across the outer surface of a test sample. By analyzing the induced surface temperature variations, and processing images collected with the infrared imager, it can be determined where material loss of the tubes has occurred. After an image sequence has been collected, a line-by-line subtraction methodology is utilized to discard irrelevant information so that defects are displayed in a re-created image. The overall goal of this project is to provide a proof of concept for a portable, hand-operated thermographic line scanner that would provide an alternative to the existing mass- and power-intensive instrument that utilizes a cooled infrared imager. In this project, two different microbolometers are first analyzed using different metal- and carbon epoxy-based targets to determine which provides better resolution for detection of subsurface, manufactured defects. The feasibility of using uncooled bolometer technology to support the development of a portable instrument to conduct this type of NDE technique was proven.

  20. Non-Destructive Evaluation of Thermal Spray Coating Interface Quality By Eddy Current Method

    SciTech Connect

    B. Mi; G. Zhao; R. Bayles

    2006-08-10

    Thermal spray coating is usually applied through directing molten or softened particles at very high velocities onto a substrate. An eddy current non-destructive inspection technique is presented here for thermal spray coating interface quality characterization. Several high-velocity-oxy-fuel (HVOF) coated steel plates were produced with various surface preparation conditions or spray process parameters. A quad-frequency eddy current probe was used to manually scan over the coating surface to evaluate the bonding quality. Experimental results show that different surface preparation conditions and varied process parameters can be successfully differentiated by the impedance value observed from the eddy current probe. The measurement is fairly robust and consistent. This non-contact, nondestructive, easy-to-use technique has the potential for evaluating the coating quality immediately after its application so that any defects can be corrected immediately.

  1. Proceedings of the Second Annual Symposium for Nondestructive Evaluation of Bond Strength

    NASA Technical Reports Server (NTRS)

    Roberts, Mark J. (Compiler)

    1999-01-01

    Ultrasonics, microwaves, optically stimulated electron emission (OSEE), and computational chemistry approaches have shown relevance to bond strength determination. Nonlinear ultrasonic nondestructive evaluation methods, however, have shown the most effectiveness over other methods on adhesive bond analysis. Correlation to changes in higher order material properties due to microstructural changes using nonlinear ultrasonics has been shown related to bond strength. Nonlinear ultrasonic energy is an order of magnitude more sensitive than linear ultrasound to these material parameter changes and to acoustic velocity changes caused by the acoustoelastic effect when a bond is prestressed. Signal correlations between non-linear ultrasonic measurements and initialization of bond failures have been measured. This paper reviews bond strength research efforts presented by university and industry experts at the Second Annual Symposium for Nondestructive Evaluation of Bond Strength organized by the NDE Sciences Branch at NASA Langley in November 1998.

  2. Nondestructive evaluation for large-scale metal-matrix composite billet processing

    NASA Astrophysics Data System (ADS)

    Shannon, R. E.; Liaw, P. K.; Harrigan, W. C.

    1992-05-01

    Nondestructive evaluation (NDE) has been conducted on a large-scale, silicon carbide paniculate (SiCp)-reinforced metal matrix composite (MMC) billet. Using powder metallurgy techniques, a 335-mm long × 349-mm diameter MMC billet was specially fabricated to contain implanted discontinuities, such as clusters of SiCp and aluminum powders, and was utilized for nondestructive characterization. Ultrasonic techniques were capable of identifying SiCp clusters in the billet, while eddy current methods could be used to determine near-surface density variation in the billets. Multiple NDE techniques could be employed to evaluate microstructural characteristics of composite billets. These results indicate that NDE techniques can be integrated into manufacturing processes to provide on-line, process-interactive control of fabrication parameters.

  3. Nondestructive evaluation of pack-diffusion coatings: A review and preliminary results

    SciTech Connect

    Gopalsami, N.; Ellingson, W.A.; Roberts, R.A.; Rose, D.N.

    1987-12-01

    This report reviews potential nondestructive evaluation (NDE) methods for coatings applicable to heat recovery systems of coal gasifiers. The review focuses mainly on aluminized, chromized, or simultaneously aluminized/chromized coatings that are produced by pack-diffusion processes on low-alloy steels such as 2 1/4Cr-1Mo and A106 carbon steels. Nondestructive evaluation is required for characterization of as-received coatings relative to acceptance criteria, and for inspection of field fabrication and repairs. In addition, NDE should play an integral role in the formulation of optimum coating specifications by establishing a relationship between coating parameters and the observed corrosion behaivor in heat-recovery system environments. NDE methods reviewed are thermal-wave imaging, scanning acoustic microscopy, ultrasonic backscattered surface waves, eddy-current testing, and X-ray fluorescence. 31 refs., 15 figs.

  4. A study of the stress wave factor technique for nondestructive evaluation of composite materials

    NASA Technical Reports Server (NTRS)

    Sarrafzadeh-Khoee, A.; Kiernan, M. T.; Duke, J. C., Jr.; Henneke, E. G., II

    1986-01-01

    The acousto-ultrasonic method of nondestructive evaluation is an extremely sensitive means of assessing material response. Efforts continue to complete the understanding of this method. In order to achieve the full sensitivity of the technique, extreme care must be taken in its performance. This report provides an update of the efforts to advance the understanding of this method and to increase its application to the nondestructive evaluation of composite materials. Included are descriptions of a novel optical system that is capable of measuring in-plane and out-of-plane displacements, an IBM PC-based data acquisition system, an extensive data analysis software package, the azimuthal variation of acousto-ultrasonic behavior in graphite/epoxy laminates, and preliminary examination of processing variation in graphite-aluminum tubes.

  5. Terahertz imaging for non-destructive evaluation of mural paintings

    NASA Astrophysics Data System (ADS)

    Jackson, J. B.; Mourou, M.; Whitaker, J. F.; Duling, I. N.; Williamson, S. L.; Menu, M.; Mourou, G. A.

    2008-02-01

    The feasibility of applying time-domain, terahertz spectroscopic imaging to the evaluation of underdrawings and paint layers embedded within wall paintings is demonstrated. Metallic and dielectric paint patterns and a graphite drawing are resolved through both paint and plaster overlayers using a pulsed-terahertz reflectometer and imaging system. We calculated the bulk refractive indices of four common pigments and used them to confirm color domains in a terahertz-beam spectral image of a painting.

  6. Nondestructive Evaluation of Advanced Fiber Reinforced Polymer Matrix Composites: A Technology Assessment

    NASA Technical Reports Server (NTRS)

    Yolken, H. Thomas; Matzkanin, George A.

    2009-01-01

    Because of their increasing utilization in structural applications, the nondestructive evaluation (NDE) of advanced fiber reinforced polymer composites continues to receive considerable research and development attention. Due to the heterogeneous nature of composites, the form of defects is often very different from a metal and fracture mechanisms are more complex. The purpose of this report is to provide an overview and technology assessment of the current state-of-the-art with respect to NDE of advanced fiber reinforced polymer composites.

  7. Method and apparatus for non-destructive evaluation of composite materials with cloth surface impressions

    NASA Technical Reports Server (NTRS)

    Madras, Eric I. (Inventor)

    1995-01-01

    A method and related apparatus for nondestructive evaluation of composite materials by determination of the quantity known as Integrated Polar Backscatter, which avoids errors caused by surface texture left by cloth impressions by identifying frequency ranges associated with peaks in a power spectrum for the backscattered signal, and removing such frequency ranges from the calculation of Integrated Polar Backscatter for all scan sites on the composite material is presented.

  8. Nondestructive Evaluation of Aircraft Composites Using Dielectric Properties and Imaging in the Terahertz Spectrum

    NASA Astrophysics Data System (ADS)

    Stoik, C. D.; Bohn, M. J.; Blackshire, J. L.

    2009-03-01

    Terahertz imaging and dielectric property measurements were assessed as nondestructive evaluation techniques for damage to aircraft glass fiber composites. Samples with localized heat damage showed a minimal change in refractive index or absorption coefficient; however, material blistering was detected. Voids were located by terahertz imaging using amplitude and phase techniques. Delamination depths were approximated by measuring the timing of Fabry-Perot reflections. Evidence of bending stress damage and simulated hidden cracks was also detected with terahertz imaging.

  9. Nondestructive evaluation of electroformed outer shells for regeneratively cooled thrust chambers

    NASA Technical Reports Server (NTRS)

    Malone, G. A.; Duscha, R. A.

    1974-01-01

    Electroforming is presently a prime technique for producing the outer jackets of regeneratively cooled thrust chambers for rocket engines. Good bond integrity of the electroformed joints adjacent to the coolant passages is important to the useful service life of these aerospace systems. This investigation demonstrated that nondestructive evaluation techniques such as ultrasonic 'C' scan, holography, and acoustic emission are capable of detecting low integrity bonds which could lead to premature failures in the subject hardware.

  10. Proposal of a new method for measuring Förster Resonance Energy Transfer (FRET) rapidly, quantitatively and non-destructively.

    PubMed

    Helm, Paul Johannes

    2012-01-01

    The process of radiationless energy transfer from a chromophore in an excited electronic state (the "donor") to another chromophore (an "acceptor"), in which the energy released by the donor effects an electronic transition, is known as "Förster Resonance Energy Transfer" (FRET). The rate of energy transfer is dependent on the sixth power of the distance between donor and acceptor. Determining FRET efficiencies is tantamount to measuring distances between molecules. A new method is proposed for determining FRET efficiencies rapidly, quantitatively, and non-destructively on ensembles containing donor acceptor pairs: at wavelengths suitable for mutually exclusive excitations of donors and acceptors, two laser beams are intensity-modulated in rectangular patterns at duty cycle ½ and frequencies ƒ(1) and ƒ(2) by electro-optic modulators. In an ensemble exposed to these laser beams, the donor excitation is modulated at ƒ(1), and the acceptor excitation, and therefore the degree of saturation of the excited electronic state of the acceptors, is modulated at ƒ(2). Since the ensemble contains donor acceptor pairs engaged in FRET, the released donor fluorescence is modulated not only at ƒ(1) but also at the beat frequency Δƒ: = |ƒ(1) - ƒ(2)|. The depth of the latter modulation, detectable via a lock-in amplifier, quantitatively indicates the FRET efficiency. PMID:23202903

  11. Remote visual inspection for nondestructive evaluation in power plants

    NASA Astrophysics Data System (ADS)

    Samsonov, Peter

    1994-02-01

    Remote visual inspection equipment such as borescopes, fiberscopes and videoimagescopes provide Power Plant NDE groups with the necessary tools for establishing superior corrective and preventative plant maintenance programs. These scopes allow the user to evaluate the condition of pipes, boilers, turbines, heat exchangers and other critical machinery without costly and time consuming disassembly. Overall plant efficiency is increased and the likelihood of catastrophic failure is reduced significantly. Ancillary equipment such as video and digital processors provide a permanent record of the inspection while employing sophisticated 3-D measurement, trend analysis, documentation and image manipulation.

  12. Efficient Nondestructive Evaluation of Prototype Carbon Fiber Reinforced Structures

    NASA Technical Reports Server (NTRS)

    Russell, Samuel S.; Walker, James; Thom, Robert (Technical Monitor)

    2002-01-01

    Thermography and shearography methods of inspection rely on optic based technologies and can reduce the time and cost required to inspect composite tanks or aerostructures. Usually areas identified as suspect in the initial inspection results are reexamined with ultrasonic methods. This combination of techniques results in a rapid and comprehensive inspection of composite structures. Development of useful defect standards will be discussed. Examples of application of this inspection philosophy to prototype, GSE, and flight hardware will be presented. Methods organizing the inspection and evaluating the results will be considered.

  13. Non-Destructive Evaluation of Wire Insulation and Coatings

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I (Inventor); Anastasi, Robert F. (Inventor)

    2004-01-01

    The present invention uses the generation and detection of acoustic guided waves to evaluate the condition of the insulation on electrical wiring. Low order axisymmetric and flexural acoustic modes are generated in the insulated wire and travel partially in the center conductor and partially in the outer insulation. The stiffness of the insulation and the insulation's condition affect the overall wave speed and amplitude of the guided wave. Analysis of the received signal provides information about the age or useful life of the wire insulation. In accordance with the present invention, signal transmission occurs at one location on the electrical wire to be evaluated, and detection occurs at one or more locations along the electrical wire. Additional receivers can be used to improve measurement accuracy. Either the transmission transducer or one or more receiver transducers may be angled at other than 90 degrees to the wire. Generation of the guided waves can be accomplished by imparting a pressure pulse on the wire. Alternative embodiments include generation via a laser, such as a Q-switched laser or a laser diode.

  14. Probabilistic nondestructive evaluation of bonded aluminum honeycomb structures

    NASA Astrophysics Data System (ADS)

    Schaefer, Lloyd A.

    1995-07-01

    Aluminum honeycomb panels fabricated in accordance with spacecraft fracture control guidelines must be evaluated to a 90/95 POD/CL (probability of detection/confidence) level for detection of the critical initial flaw (CIF) size. Severe weight limitations can drive the CIF to a size of one cell diameter, or smaller. Additionally, producibility (low or no type II errors) must be maintained, and inspection costs minimized. To assure these goals, a reliability demonstration program was undertaken on thin skin panels for the Space Station Electric Power System ORU (orbital replacement unit) enclosures. This paper examines the probabilistic NDE process in detail, including: analysis of the manufacturing methodology, expected flaw types, construction of the disbond flaw data base, and the subsequent evaluations and results using laser shearography. The experimental data is then reduced utilizing the statistical methodology outlined in a proposed military standard for NDE reliability demonstrations, and contrasted against conventional through transmission ultrasonic inspection. The effort revealed that substantial gains in system reliability and flaw type discrimination are possible with laser shearography, along with a nearly order of magnitude reduction in inspection time.

  15. Nondestructive evaluation of aircraft coatings with infrared diffuse reflectance spectra

    NASA Astrophysics Data System (ADS)

    Korth, Hans G.; Wilson, Kody A.; Gross, Kevin C.; Hawks, Michael R.; Zens, Timothy W. C.

    2015-05-01

    Aircraft coatings degrade over time, but aging can be difficult to detect before failure and delamination. We present a method to evaluate aircraft coatings in situ using infrared diffuse reflectance spectra. This method can detect and classify coating degradation much earlier than visual inspection. The method has been tested on two different types of coatings that were artificially aged in an autoclave. Spectra were measured using a hand-held diffuse reflectance infrared Fourier transform spectrometer (DRIFTS). One set of 72 samples can be classified as either aged or unaged with 100% accuracy. A second sample set contained samples that had been artificially aged for 0, 24, 48 or 96 hours. Several classification methods are compared, with accuracy better than 98% possible.

  16. [Activities of Center for Nondestructive Evaluation, Iowa State University

    NASA Technical Reports Server (NTRS)

    Gray, Joe

    2002-01-01

    The final report of NASA funded activities at Iowa State University (ISU) for the period between 1/96 and 1/99 includes two main areas of activity. The first is the development and delivery of an x-ray simulation package suitable for evaluating the impact of parameters affects the inspectability of an assembly of parts. The second area was the development of images processing tools to remove reconstruction artifacts in x-ray laminagraphy images. The x-ray simulation portion of this work was done by J. Gray and the x-ray laminagraphy work was done by J. Basart. The report is divided into two sections covering the two activities respectively. In addition to this work reported the funding also covered NASA's membership in the NSF University/Industrial Cooperative Research Center.

  17. Statistical signal processing methods for ultrasonic nondestructive evaluation

    SciTech Connect

    Saniie, J. . Dept. of Electrical and Computer Engineering)

    1992-06-01

    Order statistics and morphological filters belong to a class of nonlinear filters that have recently found many applications in signal analysis and image processing. In this paper, order statistics and morphological filters have been applied to enhance the features of the ultrasonic signal when it has been contaminated by multiple interfering microstructure echoes with random amplitudes and phases. These interfering echoes (i.e., speckles or grain scattering noise) often become significant to the point where detection of flaw echoes becomes very difficult. We have examined order statistic, and morphological filters for improved ultrasonic flaw detection. In particular, the performance of these filters has been evaluated using different ranks of order statistics (minimum, median, maximum), and different shapes of structuring elements in the application of morphological filters. The processed experimental results in testing steel samples demonstrate that these filters are capable of improving flaw detection in ultrasonic systems.

  18. Infrared Contrast Analysis Technique for Flash Thermography Nondestructive Evaluation

    NASA Technical Reports Server (NTRS)

    Koshti, Ajay

    2014-01-01

    The paper deals with the infrared flash thermography inspection to detect and analyze delamination-like anomalies in nonmetallic materials. It provides information on an IR Contrast technique that involves extracting normalized contrast verses time evolutions from the flash thermography infrared video data. The paper provides the analytical model used in the simulation of infrared image contrast. The contrast evolution simulation is achieved through calibration on measured contrast evolutions from many flat bottom holes in the subject material. The paper also provides formulas to calculate values of the thermal measurement features from the measured contrast evolution curve. Many thermal measurement features of the contrast evolution that relate to the anomaly characteristics are calculated. The measurement features and the contrast simulation are used to evaluate flash thermography inspection data in order to characterize the delamination-like anomalies. In addition, the contrast evolution prediction is matched to the measured anomaly contrast evolution to provide an assessment of the anomaly depth and width in terms of depth and diameter of the corresponding equivalent flat-bottom hole (EFBH) or equivalent uniform gap (EUG). The paper provides anomaly edge detection technique called the half-max technique which is also used to estimate width of an indication. The EFBH/EUG and half-max width estimations are used to assess anomaly size. The paper also provides some information on the "IR Contrast" software application, half-max technique and IR Contrast feature imaging application, which are based on models provided in this paper.

  19. Electromagnetic nondestructive evaluation of tempering process in AISI D2 tool steel

    NASA Astrophysics Data System (ADS)

    Kahrobaee, Saeed; Kashefi, Mehrdad

    2015-05-01

    The present paper investigates the potential of using eddy current technique as a reliable nondestructive tool to detect microstructural changes during the different stages of tempering treatment in AISI D2 tool steel. Five stages occur in tempering of the steel: precipitation of ɛ carbides, formation of cementite, retained austenite decomposition, secondary hardening effect and spheroidization of carbides. These stages were characterized by destructive methods, including dilatometry, differential scanning calorimetry, X-ray diffraction, scanning electron microscopic observations, and hardness measurements. The microstructural changes alter the electrical resistivity/magnetic saturation, which, in turn, influence the eddy current signals. Two EC parameters, induced voltage sensed by pickup coil and impedance point detected by excitation coil, were evaluated as a function of tempering temperature to characterize the microstructural features, nondestructively. The study revealed that a good correlation exists between the EC parameters and the microstructural changes.

  20. A systems approach of the nondestructive evaluation techniques applied to Scout solid rocket motors.

    NASA Technical Reports Server (NTRS)

    Oaks, A. E.

    1971-01-01

    Review and appraisal of the status of the nondestructive tests applied to Scout solid-propellant rocket motors, using analytical techniques to evaluate radiography for detecting internal discontinuities such as voids and unbonds. Information relating to selecting, performing, controlling, and evaluating the results of NDE tests was reduced to a common simplified format. With these data and the results of the analytical studies performed, it was possible to make the basic appraisals of the ability of a test to meet all pertinent acceptance criteria and, where necessary, provide suggestions to improve the situation.

  1. Quantitative, nondestructive assessment of beech scale (Hemiptera: Cryptococcidae) density using digital image analysis of wax masses.

    PubMed

    Teale, Stephen A; Letkowski, Steven; Matusick, George; Stehman, Stephen V; Castello, John D

    2009-08-01

    Beech scale, Cryptococcus fagisuga Lindinger, is a non-native invasive insect associated with beech bark disease. A quantitative method of measuring viable scale density at the levels of the individual tree and localized bark patches was developed. Bark patches (10 cm(2)) were removed at 0, 1, and 2 m above the ground and at the four cardinal directions from 13 trees in northern New York and 12 trees in northern Michigan. Digital photographs of each patch were made, and the wax mass area was measured from two random 1-cm(2) subsamples on each bark patch using image analysis software. Viable scale insects were counted after removing the wax under a dissecting microscope. Separate regression analyses at the whole tree level for the New York and Michigan sites each showed a strong positive relationship of wax mass area with the number of underlying viable scale insects. The relationships for the New York and Michigan data were not significantly different from each other, and when pooling data from the two sites, there was still a significant positive relationship between wax mass area and the number of scale insects. The relationships between viable scale insects and wax mass area were different at the 0-, 1-, and 2-m sampling heights but do not seem to affect the relationship. This method does not disrupt the insect or its interactions with the host tree. PMID:19689905

  2. Development of nondestructive non-contact acousto-thermal evaluation technique for damage detection in materials

    NASA Astrophysics Data System (ADS)

    Sathish, Shamachary; Welter, John T.; Jata, Kumar V.; Schehl, Norman; Boehnlein, Thomas

    2012-09-01

    This paper presents the development of a new non-contact acousto-thermal signature (NCATS) nondestructive evaluation technique. The physical basis of the method is the measurement of the efficiency of the material to convert acoustic energy into heat, and a theoretical model has been used to evaluate this. The increase in temperature due to conversion of acoustic energy injected into the material without direct contact was found to depend on the thermal and elastic properties of the material. In addition, it depends on the experimental parameters of the acoustic source power, the distance between sample and acoustic source, and the period of acoustic excitation. Systematic experimental approaches to optimize each of the experimental variables to maximize the observed temperature changes are described. The potential of the NCATS technique to detect microstructural-level changes in materials is demonstrated by evaluating accumulated damage due to plasticity in Ti-6Al-4V and low level thermal damage in polymer matrix composites. The ability of the technique for macroscopic applications in nondestructive evaluation is demonstrated by imaging a crack in an aluminum test sample.

  3. Non-destructive Magnetic Evaluation of Laser Weld Quality in Hot Rolled Coils

    NASA Astrophysics Data System (ADS)

    Mohapatra, J. N.; Chakradhar, I.; Rao, K. R. C.; Rao, V. V. L.; Kaza, Marutiram

    2015-06-01

    Weld quality evaluation was conducted on laser welded thin sectsions (2 mm) of hot-rolled (HR) low-carbon steel coils during cold rolling process. The analysis revealed that the poor welds consisting of the weld defects like incomplete fusion, cluster of porosity, and large difference in hardness between the weld zone and base metal were responsible for the weld failures. Experiments were conducted by varying the welding parameters; laser power and welding speed to optimize the parameters for minimizing the weld defects. The optimized weld process parameters have helped elimination of weld defects and the results are verified with microscopy and microhardness measurements. As destructive evaluation techniques are time consuming and not always permitted in industrial applications, attempts have been made in the present investigation for the utilization of suitable non-destructive techniques for the evaluation of weld quality. Non-destructive magnetic techniques of magnetic hysteresis loop and magnetic Barkhausen emissions were used in the present investigation to establish possible correlations of magnetic properties across the weld seam with the mechanical property (microhardness) for evaluation of weld quality. It is inferred that the magnetic properties of coercivity and inverse of root mean square voltage can be effectively utilized to determine weld quality in HR steel coils.

  4. Evaluation of Ultrasonic and Thermal Nondestructive Evaluation for the Characterization of Aging Degradation in Braided Composite Materials

    NASA Technical Reports Server (NTRS)

    Martin, Richard E.

    2010-01-01

    This paper examines the ability of traditional nondestructive evaluation (NDE) techniques to measure the degradation of braided polymer composite materials subjected to thermal-humidity cycling to simulate aging. A series of braided composite coupons were examined using immersion ultrasonic and pulsed thermography techniques in the as received condition. These same specimens were then examined following extended thermal-humidity cycling. Results of this examination did not show a significant change in the resulting (NDE) signals.

  5. A DATA FUSION SYSTEM FOR THE NONDESTRUCTIVE EVALUATION OF NON-PIGGABLE PIPES

    SciTech Connect

    Shreekanth Mandayam; Robi Polikar; John C. Chen

    2004-04-01

    The objectives of this research project are: (1) To design sensor data fusion algorithms that can synergistically combine defect related information from heterogeneous sensors used in gas pipeline inspection for reliably and accurately predicting the condition of the pipe-wall. (2) To develop efficient data management techniques for signals obtained during multisensor interrogation of a gas pipeline. During this reporting period, Rowan University designed, developed and exercised multisensor data fusion algorithms for identifying defect related information present in magnetic flux leakage, ultrasonic testing and thermal imaging nondestructive evaluation signatures of a test-specimen suite representative of benign and anomalous indications in gas transmission pipelines.

  6. Nondestructive Evaluation Tests Performed on Space Shuttle Leading- Edge Materials Subjected to Impact

    NASA Technical Reports Server (NTRS)

    Roth, Don J.; Martin, Richard E.; Bodis, James R.

    2005-01-01

    In support of the space shuttle Return To Flight efforts at the NASA Glenn Research Center, a series of nondestructive evaluation (NDE) tests were performed on reinforced carbon/carbon (RCC) composite panels subjected to ballistic foam impact. The impact tests were conducted to refine and verify analytical models of an external tank foam strike on the space shuttle leading edge. The NDE tests were conducted to quantify the size and location of the resulting damage zone as well as to identify hidden damage.

  7. Non-Destructive Evaluation Method and Apparatus for Measuring Acoustic Material Nonlinearity

    NASA Technical Reports Server (NTRS)

    Yost, William T. (Inventor); Cantrell, John H. (Inventor)

    2002-01-01

    An acoustic non-linearity parameter (beta) measurement method and system for Non-Destructive Evaluation (NDE) of materials and structural members obviates the need for electronic calibration of the measuring equipment. Unlike known substitutional measuring techniques requiring elaborate calibration procedures, the electrical outputs of the capacitive detector of a sample with known beta and the test sample of unknown beta are compared to determine the unknown beta. In order to provide the necessary stability of the present-inventive reference-based approach, the bandpass filters of the measurement system are maintained in a temperature-controlled environment, and the line voltage supplied to said amplifiers is well-regulated.

  8. Parallel three-dimensional acoustic and elastic wave simulation methods with applications in nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Rudd, Kevin Edward

    In this dissertation, we present two parallelized 3D simulation techniques for three-dimensional acoustic and elastic wave propagation based on the finite integration technique. We demonstrate their usefulness in solving real-world problems with examples in the three very different areas of nondestructive evaluation, medical imaging, and security screening. More precisely, these include concealed weapons detection, periodontal ultrasography, and guided wave inspection of complex piping systems. We have employed these simulation methods to study complex wave phenomena and to develop and test a variety of signal processing and hardware configurations. Simulation results are compared to experimental measurements to confirm the accuracy of the parallel simulation methods.

  9. Highly sensitive anisotropic magnetoresistance magnetometer for Eddy-current nondestructive evaluation.

    PubMed

    He, D F; Tachiki, M; Itozaki, H

    2009-03-01

    Using a commercially available anisotropic magnetoresistance (AMR) sensor of HMC1001, we developed a sensitive magnetometer. It could operate in amplifier mode or feedback mode. The magnetic field sensitivity of the AMR sensor was about 3.2 mV/V G. When the AMR sensor was biased by a voltage of 24 V, the magnetic field resolutions of the AMR magnetometer were about 12 pT/square root(Hz) at 1 kHz and 20 pT/square root(Hz) at 100 Hz. We used the AMR magnetometer for Eddy-current nondestructive evaluation in unshielded environment. PMID:19334957

  10. Using the World-Wide Web to Facilitate Communications of Non-Destructive Evaluation

    NASA Technical Reports Server (NTRS)

    McBurney, Sean

    1995-01-01

    The high reliability required for Aeronautical components is a major reason for extensive Nondestructive Testing and Evaluation. Here at Langley Research Center (LaRC), there are highly trained and certified personal to conduct such testing to prevent hazards from occurring in the workplace and on the research projects for the National Aeronautics and Space Administration (NASA). The purpose of my studies was to develop a communication source to educate others of the services and equipment offered here. This was accomplished by creating documents that are accessible to all in the industry via the World Wide Web.

  11. Evaluation of electroexplosive devices by nondestructive test techniques and impulsive waveform firings

    NASA Technical Reports Server (NTRS)

    Menichelli, V. J.

    1972-01-01

    Special requirements of the space industry for more detailed knowledge of the quality and reliability of each electroexplosive device (EED) selected for use aboard a spacecraft are described. Statistical methods do not practically demonstrate the high reliability needed. To close this gap, nondestructive test techniques and instrumentation for 1-W/1-A no-fire devices have been developed. Several lots of squibs have been evaluated using these techniques and instrumentation. They yield data as to the quality and normal behavior of each electroexplosive device without firing or degrading the unit. Performance data were obtained by initiating the EED's with an impulsive waveform and sensing the initiation characteristics, sensitivity, and output.

  12. Nondestructive evaluation tools and experimental studies for monitoring the health of space propulsion systems

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    1991-01-01

    An overview is given of background and information on space propulsion systems on both the programmatic and technical levels. Feasibility experimental studies indicate that nondestructive evaluation tools such as ultrasonic, eddy current and x-ray may be successfully used to monitor the life limiting failure mechanisms of space propulsion systems. Encouraging results were obtained for monitoring the life limiting failure mechanisms for three space propulsion systems; the degradation of tungsten arcjet and magnetoplasmadynamic electrodes; presence and thickness of spallable electrically conducting molybdenum films in ion thrusters; and the degradation of the catalyst in hydrazine thrusters.

  13. Nondestructive evaluation tools and experimental studies for monitoring the health of space propulsion systems

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    1991-01-01

    An overview is given of background and information on space propulsion systems on both the programmatic and technical levels. Feasibility experimental studies indicate that nondestructive evaluation tools such as ultrasonic, eddy current and X-ray may be successfully used to monitor the life limiting failure mechanisms of space propulsion systems. Encouraging results were obtained for monitoring the life limiting failure mechanims for three space propulsion systems: the degradation of tungsten arcjet and magnetoplasmadynamic electrodes; presence and thickness of spallable electrically conducting molybdenum films in ion thrusters; and the degradation of the catalyst in hydrazine thrusters.

  14. Nondestructive Evaluation of Foam Insulation for the External Tank Return to Flight

    NASA Technical Reports Server (NTRS)

    Walker, James L.; Richter, Joel D.

    2006-01-01

    Nondestructive evaluation methods have been developed to identify defects in the foam thermal protection system (TPS) of the Space Shuttle External Tank (ET). Terahertz imaging and backscatter radiography have been brought from prototype lab systems to production hardened inspection tools in just a few years. These methods have been demonstrated to be capable of detecting void type defects under many inches of foam which, if not repaired, could lead to detrimental foam loss. The evolution of these methods from lab tools to implementation on the ET will be discussed.

  15. Computed tomography for non-destructive evaluation of composites: Applications and correlations

    NASA Technical Reports Server (NTRS)

    Goldberg, B.; Hediger, L.; Noel, E.

    1985-01-01

    The state-of-the-art fabrication techniques for composite materials are such that stringent species-specific acceptance criteria must be generated to insure product reliability. Non-destructive evaluation techniques including computed tomography (CT), X-ray radiography (RT), and ultrasonic scanning (UT) are investigated and compared to determine their applicability and limitations to graphite epoxy, carbon-carbon, and carbon-phenolic materials. While the techniques appear complementary, CT is shown to provide significant, heretofore unattainable data. Finally, a correlation of NDE techniques to destructive analysis is presented.

  16. Non-stationary thermal wave imaging for nondestructive testing and evaluation

    NASA Astrophysics Data System (ADS)

    Mulaveesala, Ravibabu; Arora, Vanita; Siddiqui, Juned A.; Muniyappa, Amarnath

    2014-05-01

    Among various widely used Infrared Thermal Non-destructive Testing (IRTNDT) modalities, non-stationary thermal wave imaging (NSTWI) methods have proved to be an indispensable approach for the inspection and evaluation of various materials. Growing concerns of surface and subsurface defect detection capabilities with moderate peak power heat sources than the widely used conventional pulse based thermographic methods and in a reasonably less testing time compared to sinusoidal modulated lock-in thermography, make these NSTWI techniques invaluable for this field. The present work highlights a comparative study on various NSTWI techniques, further experimental results are presented to find their defect detection capabilities by taking signal to noise ratio (SNR) into consideration.

  17. Nondestructive Techniques to Evaluate the Characteristics and Development of Engineered Cartilage.

    PubMed

    Mansour, Joseph M; Lee, Zhenghong; Welter, Jean F

    2016-03-01

    In this review, methods for evaluating the properties of tissue engineered (TE) cartilage are described. Many of these have been developed for evaluating properties of native and osteoarthritic articular cartilage. However, with the increasing interest in engineering cartilage, specialized methods are needed for nondestructive evaluation of tissue while it is developing and after it is implanted. Such methods are needed, in part, due to the large inter- and intra-donor variability in the performance of the cellular component of the tissue, which remains a barrier to delivering reliable TE cartilage for implantation. Using conventional destructive tests, such variability makes it near-impossible to predict the timing and outcome of the tissue engineering process at the level of a specific piece of engineered tissue and also makes it difficult to assess the impact of changing tissue engineering regimens. While it is clear that the true test of engineered cartilage is its performance after it is implanted, correlation of pre and post implantation properties determined non-destructively in vitro and/or in vivo with performance should lead to predictive methods to improve quality-control and to minimize the chances of implanting inferior tissue. PMID:26817458

  18. Nondestructive evaluation of orthopaedic implant stability in THA using highly nonlinear solitary waves

    NASA Astrophysics Data System (ADS)

    Yang, Jinkyu; Silvestro, Claudio; Sangiorgio, Sophia N.; Borkowski, Sean L.; Ebramzadeh, Edward; De Nardo, Luigi; Daraio, Chiara

    2012-01-01

    We propose a new biomedical sensing technique based on highly nonlinear solitary waves to assess orthopaedic implant stability in a nondestructive and efficient manner. We assemble a granular crystal actuator consisting of a one-dimensional tightly packed array of spherical particles, to generate acoustic solitary waves. Via direct contact with the specimen, we inject acoustic solitary waves into a biomedical prosthesis, and we nondestructively evaluate the mechanical integrity of the bone-prosthesis interface, studying the properties of the waves reflected from the contact zone between the granular crystal and the implant. The granular crystal contains a piezoelectric sensor to measure the travelling solitary waves, which allows it to function also as a sensor. We perform a feasibility study using total hip arthroplasty (THA) samples made of metallic stems implanted in artificial composite femurs using polymethylmethacrylate for fixation. We first evaluate the sensitivity of the proposed granular crystal sensor to various levels of prosthesis insertion into the composite femur. Then, we impose a sequence of harsh mechanical loading on the THA samples to degrade the mechanical integrity at the stem-cement interfaces, using a femoral load simulator that simulates aggressive, accelerated physiological loading. We investigate the implant stability via the granular crystal sensor-actuator during testing. Preliminary results suggest that the reflected waves respond sensitively to the degree of implant fixation. In particular, the granular crystal sensor-actuator successfully detects implant loosening at the stem-cement interface following violent cyclic loading. This study suggests that the granular crystal sensor and actuator has the potential to detect metal-cement defects in a nondestructive manner for orthopaedic applications.

  19. A Quantitative, Non-Destructive Methodology for Habitat Characterisation and Benthic Monitoring at Offshore Renewable Energy Developments

    PubMed Central

    Sheehan, Emma V.; Stevens, Timothy F.; Attrill, Martin J.

    2010-01-01

    Following governments' policies to tackle global climate change, the development of offshore renewable energy sites is likely to increase substantially over coming years. All such developments interact with the seabed to some degree and so a key need exists for suitable methodology to monitor the impacts of large-scale Marine Renewable Energy Installations (MREIs). Many of these will be situated on mixed or rocky substrata, where conventional methods to characterise the habitat are unsuitable. Traditional destructive sampling is also inappropriate in conservation terms, particularly as safety zones around (MREIs) could function as Marine Protected Areas, with positive benefits for biodiversity. Here we describe a technique developed to effectively monitor the impact of MREIs and report the results of its field testing, enabling large areas to be surveyed accurately and cost-effectively. The methodology is based on a high-definition video camera, plus LED lights and laser scale markers, mounted on a “flying array” that maintains itself above the seabed grounded by a length of chain, thus causing minimal damage. Samples are taken by slow-speed tows of the gear behind a boat (200 m transects). The HD video and randomly selected frame grabs are analysed to quantify species distribution. The equipment was tested over two years in Lyme Bay, UK (25 m depth), then subsequently successfully deployed in demanding conditions at the deep (>50 m) high-energy Wave Hub site off Cornwall, UK, and a potential tidal stream energy site in Guernsey, Channel Islands (1.5 ms−1 current), the first time remote samples from such a habitat have been achieved. The next stage in the monitoring development process is described, involving the use of Remote Operated Vehicles to survey the seabed post-deployment of MREI devices. The complete methodology provides the first quantitative, relatively non-destructive method for monitoring mixed-substrate benthic communities beneath MPAs and MREIs pre- and post-device deployment. PMID:21206748

  20. A quantitative, non-destructive methodology for habitat characterisation and benthic monitoring at offshore renewable energy developments.

    PubMed

    Sheehan, Emma V; Stevens, Timothy F; Attrill, Martin J

    2010-01-01

    Following governments' policies to tackle global climate change, the development of offshore renewable energy sites is likely to increase substantially over coming years. All such developments interact with the seabed to some degree and so a key need exists for suitable methodology to monitor the impacts of large-scale Marine Renewable Energy Installations (MREIs). Many of these will be situated on mixed or rocky substrata, where conventional methods to characterise the habitat are unsuitable. Traditional destructive sampling is also inappropriate in conservation terms, particularly as safety zones around (MREIs) could function as Marine Protected Areas, with positive benefits for biodiversity. Here we describe a technique developed to effectively monitor the impact of MREIs and report the results of its field testing, enabling large areas to be surveyed accurately and cost-effectively. The methodology is based on a high-definition video camera, plus LED lights and laser scale markers, mounted on a "flying array" that maintains itself above the seabed grounded by a length of chain, thus causing minimal damage. Samples are taken by slow-speed tows of the gear behind a boat (200 m transects). The HD video and randomly selected frame grabs are analysed to quantify species distribution. The equipment was tested over two years in Lyme Bay, UK (25 m depth), then subsequently successfully deployed in demanding conditions at the deep (>50 m) high-energy Wave Hub site off Cornwall, UK, and a potential tidal stream energy site in Guernsey, Channel Islands (1.5 ms⁻¹ current), the first time remote samples from such a habitat have been achieved. The next stage in the monitoring development process is described, involving the use of Remote Operated Vehicles to survey the seabed post-deployment of MREI devices. The complete methodology provides the first quantitative, relatively non-destructive method for monitoring mixed-substrate benthic communities beneath MPAs and MREIs pre- and post-device deployment. PMID:21206748

  1. Nondestructive evaluation of soluble solid content in strawberry by near infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Guo, Zhiming; Huang, Wenqian; Chen, Liping; Wang, Xiu; Peng, Yankun

    This paper indicates the feasibility to use near infrared (NIR) spectroscopy combined with synergy interval partial least squares (siPLS) algorithms as a rapid nondestructive method to estimate the soluble solid content (SSC) in strawberry. Spectral preprocessing methods were optimized selected by cross-validation in the model calibration. Partial least squares (PLS) algorithm was conducted on the calibration of regression model. The performance of the final model was back-evaluated according to root mean square error of calibration (RMSEC) and correlation coefficient (R2 c) in calibration set, and tested by mean square error of prediction (RMSEP) and correlation coefficient (R2 p) in prediction set. The optimal siPLS model was obtained with after first derivation spectra preprocessing. The measurement results of best model were achieved as follow: RMSEC = 0.2259, R2 c = 0.9590 in the calibration set; and RMSEP = 0.2892, R2 p = 0.9390 in the prediction set. This work demonstrated that NIR spectroscopy and siPLS with efficient spectral preprocessing is a useful tool for nondestructively evaluation SSC in strawberry.

  2. Nondestructive evaluation of adhesive bond strength using the stress wave factor technique

    NASA Technical Reports Server (NTRS)

    Dos Reis, Henrique L. M.; Krautz, Harold E.

    1986-01-01

    Acousto-ultrasonic nondestructive evaluation has been conducted to evaluate the adhesive bond strength between rubber and steel plates using the stress wave factor (SWF) measurement technique. Specimens with different bond strength were manufactured and tested using the SWF technique. Two approaches were used to define the SWF. One approach defines the SWF as the signal energy and the other approach defines the SWF as the square root of the zero moment of the frequency spectrum of the received signal. The strength of the rubber-steel adhesive joint was then evaluated using the destructive peel strength test method. It was observed that in both approaches higher values of the SWF measurements correspond to higher values of the peel strength test data. Therefore, these results show that the stress wave factor technique has the potential of being used in quality assurance of the adhesive bond strength between rubber and steel substrates.

  3. Nondestructive evaluation of ceramic and metal matrix composites for NASA's HITEMP and enabling propulsion materials programs

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    1992-01-01

    In a preliminary study, ultrasonic, x-ray opaque, and fluorescent dye penetrants techniques were used to evaluate and characterize ceramic and metal matrix composites. Techniques are highlighted for identifying porosity, fiber alignment, fiber uniformity, matrix cracks, fiber fractures, unbonds or disbonds between laminae, and fiber-to-matrix bond variations. The nondestructive evaluations (NDE) were performed during processing and after thermomechanical testing. Specific examples are given for Si3N4/SiC (SCS-6 fiber), FeCrAlY/Al2O3 fibers, Ti-15-3/SiC (SCS-6 fiber) materials, and Si3N4/SiC (SCS-6 fiber) actively cooled panel components. Results of this study indicate that the choice of the NDE tools to be used can be optimized to yield a faithful and accurate evaluation of advanced composites.

  4. Research Performed within the Non-Destructive Evaluation Team at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Burns, Erin A.

    2004-01-01

    Non-destructive testing is essential in many fields of manufacturing and research in order to perform reliable examination of potentially damaged materials and parts without destroying the inherent structure of the materials. Thus, the Non-Destructive Evaluation (NDE) Team at NASA Glenn Research Center partakes in various projects to improve materials testing equipment as well as analyze materials, material defects, and material deficiencies. Due to the array of projects within the NDE Team at this time, five research aims were supplemental to some current projects. A literature survey of "DE and testing methodologies as related to rocks was performed. Also, Mars Expedition Rover technology was assessed to understand the requirements for instrumentation in harsh space environments (e.g. temperature). Potential instrumentation and technologies were also considered and documented. The literature survey provided background and potential sources for a proposal to acquire funding for ultrasonic instrumentation on board a future Mars expedition. The laboratory uses a Santec Systems AcousticScope AS200 acoustography system. Labview code was written within the current program in order to improve the current performance of the acoustography system. A sample of Reinforced Carbon/Carbon (RCC) material from the leading edge of the space shuttle underwent various non-destructive tests (guided wave scanning, thermography, computed tomography, real time x-ray, etc.) in order to characterize its structure and examine possible defects. Guided wave scan data of a ceramic matrix composite (CMC) panel was reanalyzed utilizing image correlations and signal processing variables. Additional guided wave scans and thermography were also performed on the CMC panel. These reevaluated data and images will be used in future presentations and publications. An additional axis for the guided wave scanner was designed, constructed, and implemented. This additional axis allowed incremental spacing of the previously fixed transducers for ultrasonic velocity measurements.

  5. Shearography for Non-Destructive Evaluation with Applications to BAT Mask Tile Adhesive Bonding and Specular Surface Honeycomb Panels

    NASA Technical Reports Server (NTRS)

    Lysak, Daniel B.

    2003-01-01

    In this report we examine the applicability of shearography techniques for nondestructive inspection and evaluation in two unique application areas. In the first application, shearography is used to evaluate the quality of adhesive bonds holding lead tiles to the BAT gamma ray mask for the NASA Swift program. By exciting the mask with a vibration, the more poorly bonded tiles can be distinguished by their greater displacement response, which is readily identifiable in the shearography image. A quantitative analysis is presented that compares the shearography results with a destructive pull test measuring the force at bond failure. Generally speaking, the results show good agreement. Further investigation would be useful to optimize certain test parameters such as vibration frequency and amplitude. The second application is to evaluate the bonding between the skin and core of a honeycomb structure with a specular (mirror-like) surface. In standard shearography techniques, the object under test must have a diffuse surface to generate the speckle patterns in laser light, which are then sheared. A novel configuration using the specular surface as a mirror to image speckles from a diffuser is presented, opening up the use of shearography to a new class of objects that could not have been examined with the traditional approach. This new technique readily identifies large scale bond failures in the panel, demonstrating the validity of this approach. For the particular panel examined here, some scaling issues should be examined further to resolve the measurement scale down to the very small size of the core cells. In addition, further development should be undertaken to determine the general applicability of the new approach and to establish a firm quantitative foundation.

  6. Non-destructive evaluation of depth of surface cracks using ultrasonic frequency analysis.

    PubMed

    Her, Shiuh-Chuan; Lin, Sheng-Tung

    2014-01-01

    Ultrasonic is one of the most common uses of a non-destructive evaluation method for crack detection and characterization. The effectiveness of the acoustic-ultrasound Structural Health Monitoring (SHM) technique for the determination of the depth of the surface crack was presented. A method for ultrasonic sizing of surface cracks combined with the time domain and frequency spectrum was adopted. The ultrasonic frequency spectrum was obtained by Fourier transform technique. A series of test specimens with various depths of surface crack ranging from 1 mm to 8 mm was fabricated. The depth of the surface crack was evaluated using the pulse-echo technique. In this work, three different longitudinal waves with frequencies of 2.25 MHz, 5 MHz and 10 MHz were employed to investigate the effect of frequency on the sizing detection of surface cracks. Reasonable accuracies were achieved with measurement errors less than 7%. PMID:25225875

  7. An Electromagnetic Sensor with a Metamaterial Lens for Nondestructive Evaluation of Composite Materials

    PubMed Central

    Savin, Adriana; Steigmann, Rozina; Bruma, Alina; Šturm, Roman

    2015-01-01

    This paper proposes the study and implementation of a sensor with a metamaterial (MM) lens in electromagnetic nondestructive evaluation (eNDE). Thus, the use of a new type of MM, named Conical Swiss Rolls (CSR) has been proposed. These structures can serve as electromagnetic flux concentrators in the radiofrequency range. As a direct application, plates of composite materials with carbon fibers woven as reinforcement and polyphenylene sulphide as matrix with delaminations due to low energy impacts were examined. The evaluation method is based on the appearance of evanescent modes in the space between carbon fibers when the sample is excited with a transversal magnetic along z axis (TMz) polarized electromagnetic field. The MM lens allows the transmission and intensification of evanescent waves. The characteristics of carbon fibers woven structure became visible and delaminations are clearly emphasized. The flaws can be localized with spatial resolution better than λ/2000. PMID:26151206

  8. Nondestructive evaluation of photosynthesis by delayed luminescence in Arabidopsis in Petri dishes.

    PubMed

    Chuenwarin, Paweena; Shimazaki, Azumi; Shimizu, Masanori; Kobayashi, Yuko; Katsumata, Masakazu; Kobayashi, Hirokazu

    2016-03-01

    Nondestructive evaluation of photosynthesis is a valuable tool in the field and laboratory. Delayed luminescence (DL) can reflect charge recombination through the backflow of electrons. However, DL detection has not yet been adapted for whole plants in Petri dishes. To compensate for differences in DL decay between sibling Arabidopsis plants grown under the same conditions, we developed a time-sequential double measurement method. Using this method, we examined the influence of photosynthetic electron flow inhibitors, and differences in the DL decay curves were categorized by considering the initial and late phases of the decay curves, as well as their intermediate slopes. The appearance of concavity and convexity in DL curves in Arabidopsis was different from unicellular algae, suggesting complexity in the photosynthetic machinery of higher plants. This detection method should be invaluable for evaluating photosynthetic defects in higher plants under sterile conditions without interrupting plant culture. PMID:26559425

  9. Electromagnetic Thermography Nondestructive Evaluation: Physics-based Modeling and Pattern Mining.

    PubMed

    Gao, Bin; Woo, Wai Lok; Tian, Gui Yun

    2016-01-01

    Electromagnetic mechanism of Joule heating and thermal conduction on conductive material characterization broadens their scope for implementation in real thermography based Nondestructive testing and evaluation (NDT&E) systems by imparting sensitivity, conformability and allowing fast and imaging detection, which is necessary for efficiency. The issue of automatic material evaluation has not been fully addressed by researchers and it marks a crucial first step to analyzing the structural health of the material, which in turn sheds light on understanding the production of the defects mechanisms. In this study, we bridge the gap between the physics world and mathematical modeling world. We generate physics-mathematical modeling and mining route in the spatial-, time-, frequency-, and sparse-pattern domains. This is a significant step towards realizing the deeper insight in electromagnetic thermography (EMT) and automatic defect identification. This renders the EMT a promising candidate for the highly efficient and yet flexible NDT&E. PMID:27158061

  10. Modified nondestructive colorimetric method to evaluate the variability of oxygen diffusion rate through wine bottle closures.

    PubMed

    Brotto, Laura; Battistutta, Franco; Tat, Lara; Comuzzo, Piergiorgio; Zironi, Roberto

    2010-03-24

    Some modifications to a previous nondestructive colorimetric method that permits evaluation of the oxygen diffusion rate through wine closures were proposed. The method is based on the reaction of indigo carmine solution with oxygen and the tristimulus measurement of the consequent color change. Simplified preparation and measurement procedures were set up, allowing the analysis of a large number of samples simultaneously. The method was applied to the evaluation of the variability within the lot of 20 different types of stoppers (synthetic, produced by molding, and natural cork). The closures were tested at a storage temperature of 26 degrees C. With regard to oxygen permeability, the natural cork stopper showed a low homogeneity within the lot, especially during the first month after bottling, whereas the synthetic closure showed a greater steadiness in the performance. The limits of the colorimetric method were also analyzed, and three possible causes of degradation of the indigo carmine solution were identified: oxygen, light, and heat. PMID:20187636

  11. Electromagnetic Thermography Nondestructive Evaluation: Physics-based Modeling and Pattern Mining

    PubMed Central

    Gao, Bin; Woo, Wai Lok; Tian, Gui Yun

    2016-01-01

    Electromagnetic mechanism of Joule heating and thermal conduction on conductive material characterization broadens their scope for implementation in real thermography based Nondestructive testing and evaluation (NDT&E) systems by imparting sensitivity, conformability and allowing fast and imaging detection, which is necessary for efficiency. The issue of automatic material evaluation has not been fully addressed by researchers and it marks a crucial first step to analyzing the structural health of the material, which in turn sheds light on understanding the production of the defects mechanisms. In this study, we bridge the gap between the physics world and mathematical modeling world. We generate physics-mathematical modeling and mining route in the spatial-, time-, frequency-, and sparse-pattern domains. This is a significant step towards realizing the deeper insight in electromagnetic thermography (EMT) and automatic defect identification. This renders the EMT a promising candidate for the highly efficient and yet flexible NDT&E. PMID:27158061

  12. Nondestructive Evaluation of the J-2X Direct Metal Laser Sintered Gas Generator Discharge Duct

    NASA Technical Reports Server (NTRS)

    Esther, Elizabeth A.; Beshears, Ronald D.; Lash, Rhonda K.

    2012-01-01

    The J-2X program at NASA's Marshall Space Flight Center (MSFC) procured a direct metal laser sintered (DMLS) gas generator discharge duct from Pratt & Whitney Rocketdyne and Morris Technologies for a test program that would evaluate the material properties and durability of the duct in an engine-like environment. DMLS technology was pursued as a manufacturing alternative to traditional techniques, which used off nominal practices to manufacture the gas generator duct's 180 degree turn geometry. MSFC's Nondestructive Evaluation (NDE) Team performed radiographic, ultrasonic, computed tomographic, and fluorescent penetrant examinations of the duct. Results from the NDE examinations reveal some shallow porosity but no major defects in the as-manufactured material. NDE examinations were also performed after hot-fire testing the gas generator duct and yielded similar results pre and post-test and showed no flaw growth or development.

  13. Non-Destructive Evaluation of Depth of Surface Cracks Using Ultrasonic Frequency Analysis

    PubMed Central

    Her, Shiuh-Chuan; Lin, Sheng-Tung

    2014-01-01

    Ultrasonic is one of the most common uses of a non-destructive evaluation method for crack detection and characterization. The effectiveness of the acoustic-ultrasound Structural Health Monitoring (SHM) technique for the determination of the depth of the surface crack was presented. A method for ultrasonic sizing of surface cracks combined with the time domain and frequency spectrum was adopted. The ultrasonic frequency spectrum was obtained by Fourier transform technique. A series of test specimens with various depths of surface crack ranging from 1 mm to 8 mm was fabricated. The depth of the surface crack was evaluated using the pulse-echo technique. In this work, three different longitudinal waves with frequencies of 2.25 MHz, 5 MHz and 10 MHz were employed to investigate the effect of frequency on the sizing detection of surface cracks. Reasonable accuracies were achieved with measurement errors less than 7%. PMID:25225875

  14. Yucca Mountain project container fabrication, closure and non-destructive evaluation development activities; Summary and viewgraphs

    SciTech Connect

    Russell, E.W.; Nelson, T.A.

    1989-06-01

    In this presentation, container fabrication, closure, and non-destructive evaluation (NDE) process development activities are described. All of these activities are interrelated, and will contribute to the metal barrier selection activity. The plan is to use a corrosion-resistant material in the form of a cylinder with a wall thickness of {approximately}1cm (2cm for pure copper.) The materials under consideration include the three austenitic alloys: stainless steel-304L, stainless steel-316L and alloy 825, as well as the three copper alloys: CDA 102, CDA 613, and CDA 715. This document reviews the recommended procedures and processes for fabricating, closing and evaluating each of the candidate materials. (KGD)

  15. Study of concrete drilling for automated non-destructive evaluation and rehabilitation system for bridge decks

    NASA Astrophysics Data System (ADS)

    Trkov, Mitja; Liu, Fei; Yi, Jingang; Baruh, Haim

    2011-04-01

    Robotic drilling is the basic process for the non-destructive rehabilitation (NDR) system in the Automated Non-destructive Evaluation and Rehabilitation System (ANDERS) for bridge decks. In this paper, we present a study and testing of a concrete drilling process that is used for robotic drilling process for bridge decks repair. We first review the ANDERS and NDR design. Then we present the experimental setup for the drilling process study. A set of testing experiments are performed considering drilling process parameters such as drill bit size, drill rotating speed, drill thrust force and types of concrete composites. Based on the experiments and analysis, we identify and find that the optimal set of drilling process parameters for the ANDERS application is 1/4-inch bit size, drill rotational speed of 1500 rpm and thrust force around 35 lbs. We also demonstrate that the monitoring of drill feeding displacement and thrust force cannot be used to detect and identify the cracks in bridge decks.

  16. Nondestructive test methods for evaluating durability of concrete highway structures: experience of Ontario Ministry of Transportation

    NASA Astrophysics Data System (ADS)

    Ip, Alan; Berszakiewicz, Beata; Pianca, Frank

    1998-03-01

    There is an urgent need for fast, reliable, non-destructive test methods to measure permeability and resistivity of concrete in the field, in order to assess the performance of concrete structures and confirm the benefits of the use of new materials. The application of high performance concrete for rehabilitation of corrosion-damaged highway structures and for new bridge construction has increased in Ontario over the past few years. High performance concrete, containing supplementary cementing materials such as silica fume, typically has lower permeability and higher electrical resistivity than conventional concrete. Since 1993, the R&D staff of the Ontario Ministry of Transportation (MTO) has been evaluating various non-destructive in-situ techniques to measure the permeability and resistivity of concrete. This paper describes two methods used by MTO to measure the permeability of concrete: surface water absorption and air permeability techniques; and presents the methods used to measure the concrete electrical resistivity, chloride movement in the concrete, and corrosion activity of the embedded steel. Many of the tests were performed on both the conventional and high performance concrete. Some of these techniques can be potentially used as quality assurance tools for assessing the quality, performance and durability of concrete in the field.

  17. A nondestructive method for evaluating in vitro osteoblast differentiation on biomaterials using osteoblast-specific fluorescence.

    PubMed

    Kuhn, Liisa T; Liu, Yongxing; Advincula, Maria; Wang, Yu-Hsiung; Maye, Peter; Goldberg, A Jon

    2010-12-01

    Transgenic mice with a Col1a1-promoter-driven transgene pOBCol2.3GFP were previously developed to visually identify mature osteoblasts through fluorescent expression. Our goal was to determine if this technology could be used to nondestructively evaluate the in vitro differentiation of osteoprogenitor cells on biomaterials such as biomimetic carbonated hydroxyapatite (cHA). Primary osteoprogenitor cells were harvested from calvaria of neonatal Col2.3GFP transgenic mice and cultured on cHA and a tissue culture polystyrene (TCPS) control. The distribution of intensities and area percentage of green fluorescent protein (GFP)-positive cells were quantified using fluorimetry and image analysis of fluorescent microscopy. At 14 days, an increased area and higher mean intensity of GFP-positive cells was observed on cHA as compared to TCPS, indicating more rapid differentiation on cHA. Notably, there were large continuous regions of GFP-positive osteoblasts on cHA, in contrast to the sparse, nodules of osteoblasts on TCPS, implying that cHA provides an osteogenic cue to cells. Xylenol orange staining was capable of distinguishing osteoblast-initiated mineral from the cHA substrate. With this method the unique pattern of osteoblast differentiation on cHA was clearly observed for the first time. Importantly, the generalized method can be used for rapid, high-throughput, nondestructive screening of biomaterials intended to enhance osteogenic differentiation. PMID:20337515

  18. Non-Destructive Evaluation of Grain Structure Using Air-Coupled Ultrasonics

    SciTech Connect

    Belvin, A. D.; Burrell, R. K.; Cole, E.G.

    2009-08-01

    Cast material has a grain structure that is relatively non-uniform. There is a desire to evaluate the grain structure of this material non-destructively. Traditionally, grain size measurement is a destructive process involving the sectioning and metallographic imaging of the material. Generally, this is performed on a representative sample on a periodic basis. Sampling is inefficient and costly. Furthermore, the resulting data may not provide an accurate description of the entire part's average grain size or grain size variation. This project is designed to develop a non-destructive acoustic scanning technique, using Chirp waveforms, to quantify average grain size and grain size variation across the surface of a cast material. A Chirp is a signal in which the frequency increases or decreases over time (frequency modulation). As a Chirp passes through a material, the material's grains reduce the signal (attenuation) by absorbing the signal energy. Geophysics research has shown a direct correlation with Chirp wave attenuation and mean grain size in geological structures. The goal of this project is to demonstrate that Chirp waveform attenuation can be used to measure grain size and grain variation in cast metals (uranium and other materials of interest). An off-axis ultrasonic inspection technique using air-coupled ultrasonics has been developed to determine grain size in cast materials. The technique gives a uniform response across the volume of the component. This technique has been demonstrated to provide generalized trends of grain variation over the samples investigated.

  19. Measurement techniques and application of electrical properties for nondestructive quality evaluation of foods-a review.

    PubMed

    Jha, Shyam Narayan; Narsaiah, K; Basediya, A L; Sharma, Rajiv; Jaiswal, Pranita; Kumar, Ramesh; Bhardwaj, Rishi

    2011-08-01

    Non-destructive systems are recent trends for quality evaluation of fruits and vegetables. Information on post-harvest variations in electrical properties is needed to develop new instruments for this purpose. Electrical properties are finding increasing application in agriculture and food processing industries. Knowledge of dielectric properties of foods as a function of moisture content and temperature is essential in the design and control of drying systems. As simple, rapid and non-destructive measuring techniques, dielectric spectroscopy provides information about the dielectric response of materials to electromagnetic field. Electrical properties of agricultural materials have been of interest for many years. The interest in dielectric properties of materials has historically been associated with the design of electrical equipment. This review paper covers theoretical aspects of different electrical properties, their measurement techniques, applications of dielectric properties in agriculture/food processing sector and potential applications of thermal imaging (TI) for quality and safety assessment in food processing. The values of dielectric properties of a number of products including food grains, fruits and vegetables, and meat and meat products are presented in table form. This comprehensive coverage will be useful for academic, scientific and industrial community in treating and applying the facts in developing/testing new processes and products based on electromagnetic energy application. PMID:23572764

  20. High-speed terahertz reflection three-dimensional imaging for nondestructive evaluation.

    PubMed

    Jin, Kyong Hwan; Kim, Young-Gil; Cho, Seung Hyun; Ye, Jong Chul; Yee, Dae-Su

    2012-11-01

    We demonstrate high-speed terahertz (THz) reflection three-dimensional (3D) imaging based on electronically controlled optical sampling (ECOPS). ECOPS enables scanning of an axial range of 9 mm in free space at 1 kHz. It takes 80 s to scan a transverse range of 100 mm × 100 mm along a zigzag trajectory that consists of 200 lines using translation stages. To show applicability of the imaging system to nondestructive evaluation, a THz reflection 3D image of an artificially made sample is obtained, which is made of glass fiber reinforced polymer composite material and has defects such as delamination and inclusion, and is compared with an ultrasonic reflection 3D image of the sample. PMID:23187360

  1. Nondestructive Image Evaluation of Welded Zone of Steel Plate using Photoacoustic Microscope

    NASA Astrophysics Data System (ADS)

    Ohtaki, Naoki; Hatake-yama, Mika; Suzuki, Mamoru; Endoh, Haruo; Hoshimiya, Tsutomu; Kawakami, Masaru; Muraki, Yutaka; Nakajima, Takeshi; Tominaga, Akihide; Takeshi, Masami

    2007-07-01

    The nondestructive evaluation (NDE) of welded steel plates was performed using photoacoustic microscope (PAM). Specimens were prepared by changing the maximum welding current to 5, 6.5, and 8 kA. A noncontact inspection without having to assemble a transducer was performed, and the results were compared with those of destructive inspection using an optical microscope. The agreement of NDE using a PAM and results from an actual shear fracture destructive test was good. The large fluctuation in the PA signal measured for the steel plates welded at the small current suggests the inhomogeneity of the inside welded region. Furthermore, visualization of the welded region suggests the feasibility of obtaining information on the status or uniformity of the inner welded region, which is difficult to measure by the other methods.

  2. System and method for non-destructive evaluation of surface characteristics of a magnetic material

    DOEpatents

    Jiles, David C.; Sipahi, Levent B.

    1994-05-17

    A system and a related method for non-destructive evaluation of the surface characteristics of a magnetic material. The sample is excited by an alternating magnetic field. The field frequency, amplitude and offset are controlled according to a predetermined protocol. The Barkhausen response of the sample is detected for the various fields and offsets and is analyzed. The system produces information relating to the frequency content, the amplitude content, the average or RMS energy content, as well as count rate information, for each of the Barkhausen responses at each of the excitation levels applied during the protocol. That information provides a contiguous body of data, heretofore unavailable, which can be analyzed to deduce information about the surface characteristics of the material at various depths below the surface.

  3. Bonding and nondestructive evaluation of graphite/PEEK composite and titanium adherends with thermoplastic adhesives

    NASA Technical Reports Server (NTRS)

    Hodges, W. T.; Tyeryar, J. R.; Berry, M.

    1985-01-01

    Bonded single overlap shear specimens were fabricated from Graphite/PEEK (Polyetheretherketone) composite adherends and titanium adherends. Six advanced thermoplastic adhesives were used for the bonding. The specimens were bonded by an electromagnetic induction technique producing high heating rates and high-strength bonds in a few minutes. This contrasts with conventionally heated presses or autoclaves that take hours to process comparable quality bonds. The Graphite/PEEK composites were highly resistant to delamination during the testing. This allowed the specimen to fail exclusively through the bondline, even at very high shear loads. Nondestructive evaluation of bonded specimens was performed ultrasonically by energizing the entire thickness of the material through the bondline and measuring acoustic impedance parameters. Destructive testing confirmed the unique ultrasonic profiles of strong and weak bonds, establishing a standard for predicting relative bond strength in subsequent specimens.

  4. A DATA FUSION SYSTEM FOR THE NONDESTRUCTIVE EVALUATION OF NON-PIGGABLE PIPES

    SciTech Connect

    Dr. Shreekanth Mandayam; Dr. Robi Polikar; Dr. John C. Chen

    2003-06-01

    The objectives of this research project are: (1) To design sensor data fusion algorithms that can synergistically combine defect related information from heterogeneous sensors used in gas pipeline inspection for reliably and accurately predicting the condition of the pipe-wall. (2) To develop efficient data management techniques for signals obtained during multisensor interrogation of a gas pipeline. During this reporting period, Rowan University fabricated test specimens with simulated defects for nondestructive evaluation (NDE); designed and developed two versions of a test platform for performing multi-sensor interrogation of test specimens under loaded conditions simulating pressurized gas pipelines; and performed acoustic emission (AE) NDE on the test specimens. The data resulting from this work will be employed for designing multi-sensor data fusion algorithms during the next reporting period.

  5. Review of nonlinear ultrasonic guided wave nondestructive evaluation: theory, numerics, and experiments

    NASA Astrophysics Data System (ADS)

    Chillara, Vamshi Krishna; Lissenden, Cliff J.

    2016-01-01

    Interest in using the higher harmonic generation of ultrasonic guided wave modes for nondestructive evaluation continues to grow tremendously as the understanding of nonlinear guided wave propagation has enabled further analysis. The combination of the attractive properties of guided waves with the attractive properties of higher harmonic generation provides a very unique potential for characterization of incipient damage, particularly in plate and shell structures. Guided waves can propagate relatively long distances, provide access to hidden structural components, have various displacement polarizations, and provide many opportunities for mode conversions due to their multimode character. Moreover, higher harmonic generation is sensitive to changing aspects of the microstructures such as to the dislocation density, precipitates, inclusions, and voids. We review the recent advances in the theory of nonlinear guided waves, as well as the numerical simulations and experiments that demonstrate their utility.

  6. Nanomanipulation and Lithography for Carbon Nanotube Based Nondestructive Evaluation Sensor Development

    NASA Technical Reports Server (NTRS)

    Wincheski, Buzz; Smits, Jan; Namkung, Min; Ingram, JoAnne; Watkins, Neal; Jordan, Jeffrey D.; Louie, Richard

    2002-01-01

    Carbon nanotubes (CNTs) offer great potential for advanced sensor development due to the unique electronic transport properties of the material. However, a significant obstacle to the realization of practical CNT devices is the formation of reliable and reproducible CNT to metallic contacts. In this work, scanning probe techniques are explored for both fabrication of metallic junctions and positioning of singlewalled CNTs across these junctions. The use of a haptic force feedback interface to a scanning probe microscope is used to enable movement of nanotubes over micron length scales with nanometer precision. In this case, imaging of the surface is performed with light or intermittent contact to the surface. Increased tip-to-sample interaction forces are then applied to either create junctions or position CNTs. The effect of functionalization of substrate surfaces on the movement and tribology of the materials is also studied. The application of these techniques to the fabrication of CNT-based sensors for nondestructive evaluation applications is discussed.

  7. The Evolution of Nondestructive Evaluation Methods for the Space Shuttle External Tank Thermal Protection System

    NASA Technical Reports Server (NTRS)

    Walker, James L.; Richter, Joel D.

    2006-01-01

    Three nondestructive evaluation methods are being developed to identify defects in the foam thermal protection system (TPS) of the Space Shuttle External Tank (ET). Shearography is being developed to identify shallow delaminations, shallow voids and crush damage in the foam while terahertz imaging and backscatter radiography are being developed to identify voids and cracks in thick foam regions. The basic theory of operation along with factors affecting the results of these methods will be described. Also, the evolution of these methods from lab tools to implementation on the ET will be discussed. Results from both test panels and flight tank inspections will be provided to show the range in defect sizes and types that can be readily detected.

  8. Step-frequency radar imaging for nondestructive evaluation (NDE) and ground-penetrating radar (GPR) applications

    NASA Astrophysics Data System (ADS)

    Weedon, William H.; Chew, Weng C.; Ruwe, Chad A.

    1994-09-01

    We describe a step-frequency microwave radar imaging system that is suitable for nondestructive evaluation (NDE) and ground-penetrating radar (GPR) applications. The system includes a computer-automated microwave measurement apparatus along with nonlinear inverse scattering imaging algorithms. Through the use of an inverse Fourier transform, the SFR data is transformed into a synthetic time-domain pulse, and imaging algorithms are applied to the time-domain data. A calibration procedure involving the use of calibration targets is described in order to remove pulse distortions due to the effective aperture and dispersive nature of the antennas, as well as those distortions due to connectors, transmission lines, directional couplers and amplifiers. Reconstructions of various metallic and dielectric scattering objects including metallic rods, glass rods and plastic PVC pipes from real measurement data collected in our laboratory are shown.

  9. A sparse digital signal model for ultrasonic nondestructive evaluation of layered materials.

    PubMed

    Bochud, N; Gomez, A M; Rus, G; Peinado, A M

    2015-09-01

    Signal modeling has been proven to be an useful tool to characterize damaged materials under ultrasonic nondestructive evaluation (NDE). In this paper, we introduce a novel digital signal model for ultrasonic NDE of multilayered materials. This model borrows concepts from lattice filter theory, and bridges them to the physics involved in the wave-material interactions. In particular, the proposed theoretical framework shows that any multilayered material can be characterized by a transfer function with sparse coefficients. The filter coefficients are linked to the physical properties of the material and are analytically obtained from them, whereas a sparse distribution naturally arises and does not rely on heuristic approaches. The developed model is first validated with experimental measurements obtained from multilayered media consisting of homogeneous solids. Then, the sparse structure of the obtained digital filter is exploited through a model-based inverse problem for damage identification in a carbon fiber-reinforced polymer (CFRP) plate. PMID:26092090

  10. Challenges in Integrating Nondestructive Evaluation and Finite Element Methods for Realistic Structural Analysis

    NASA Technical Reports Server (NTRS)

    Abdul-Aziz, Ali; Baaklini, George Y.; Zagidulin, Dmitri; Rauser, Richard W.

    2000-01-01

    Capabilities and expertise related to the development of links between nondestructive evaluation (NDE) and finite element analysis (FEA) at Glenn Research Center (GRC) are demonstrated. Current tools to analyze data produced by computed tomography (CT) scans are exercised to help assess the damage state in high temperature structural composite materials. A utility translator was written to convert velocity (an image processing software) STL data file to a suitable CAD-FEA type file. Finite element analyses are carried out with MARC, a commercial nonlinear finite element code, and the analytical results are discussed. Modeling was established by building MSC/Patran (a pre and post processing finite element package) generated model and comparing it to a model generated by Velocity in conjunction with MSC/Patran Graphics. Modeling issues and results are discussed in this paper. The entire process that outlines the tie between the data extracted via NDE and the finite element modeling and analysis is fully described.

  11. Integrated Nondestructive Evaluation and Finite Element Analysis Predicts Crack Location and Shape

    NASA Technical Reports Server (NTRS)

    Abdul-Azia, Ali; Baaklini, George Y.; Trudell, Jeffrey J.

    2002-01-01

    This study describes the finite-element analyses and the NDE modality undertaken on two flywheel rotors that were spun to burst speed. Computed tomography and dimensional measurements were used to nondestructively evaluate the rotors before and/or after they were spun to the first crack detection. Computed tomography data findings of two- and three-dimensional crack formation were used to conduct finite-element (FEA) and fracture mechanics analyses. A procedure to extend these analyses to estimate the life of these components is also outlined. NDE-FEA results for one of the rotors are presented in the figures. The stress results, which represent the radial stresses in the rim, clearly indicate that the maximum stress region is within the section defined by the computed tomography scan. Furthermore, the NDE data correlate well with the FEA results. In addition, the measurements reported show that the NDE and FEA data are in parallel.

  12. Nondestructive Evaluation of Additive Manufacturing State-of-the-Discipline Report

    NASA Technical Reports Server (NTRS)

    Waller, Jess M.; Parker, Bradford H.; Hodges, Kenneth L.; Burke, Eric R.; Walker, James L.

    2014-01-01

    This report summarizes the National Aeronautics and Space Administrations (NASA) state of the art of nondestructive evaluation (NDE) for additive manufacturing (AM), or "3-D printed", hardware. NASA's unique need for highly customized spacecraft and instrumentation is suited for AM, which offers a compelling alternative to traditional subtractive manufacturing approaches. The Agency has an opportunity to push the envelope on how this technology is used in zero gravity, an enable in-space manufacturing of flight spares and replacement hardware crucial for long-duration, manned missions to Mars. The Agency is leveraging AM technology developed internally and by industry, academia, and other government agencies for its unique needs. Recent technical interchange meetings and workshops attended by NASA have identified NDE as a universal need for all aspects of additive manufacturing. The impact of NDE on AM is cross cutting and spans materials, processing quality assurance, testing and modeling disciplines. Appropriate NDE methods are needed before, during, and after the AM production process.

  13. The National Aeronautics and Space Administration Nondestructive Evaluation Program for Safe and Reliable Operations

    NASA Astrophysics Data System (ADS)

    Generazio, Ed

    2006-03-01

    The National Aeronautics and Space Administration (NASA) Nondestructive Evaluation (NDE) Program is presented. As a result of the loss of seven astronauts and the Space Shuttle Columbia on February 1, 2003, NASA has undergone many changes in its organization. NDE is one of the key areas that are recognized by the Columbia Accident Investigation Board (CAIB) that needed to be strengthened by warranting NDE as a discipline with Independent Technical Authority (iTA). The current NASA NDE system and activities are presented including the latest developments in inspection technologies being applied to the Space Transportation System (STS). The unfolding trends and directions in NDE for the future are discussed as they apply to assuring safe and reliable operations.

  14. Nondestructive test and evaluation at the Carderock Division, Naval Surface Warfare Center, Philadelphia site

    NASA Astrophysics Data System (ADS)

    Leinbach, Russell A., Jr.

    1995-06-01

    Carderock Division, Naval Surface Warfare Center, Code 623 has been involved in the nondestructive test and evaluation of US Navy surface vessels since the 1960s. In this time, CDNSWC 623 has been involved in the utilization and technical development of many forms of NDE including visual inspection, contact ultrasonics, eddy current inspections, computer- automated ultrasonics, and laser optics. The present laser optic tube inspection system (LOTIS) was developed through a joint venture between NSWCCD 623 and Quest Integrated, Inc. of Kent, WA. CDNSWC 623 is presently involved in the centralization of several fleet- wide NDE practices including boiler inspection devices, contact ultrasonics, eddy current, the ultrasonic tube inspection system, and the LOTIS. These systems all have very diverse ranges of application and have proven to be cost-saving devices when implemented throughout the US Navy.

  15. Research and Development Roadmaps for Nondestructive Evaluation of Cables, Concrete, Reactor Pressure Vessels, and Piping Fatique

    SciTech Connect

    Clayton, Dwight A; Bakhtiari, Sasan; Smith, Cyrus M; Simmons, Kevin; Ramuhalli, Pradeep; Coble, Jamie; Brenchley, David; Meyer, Ryan

    2013-01-01

    To address these research needs, the MAaD Pathway supported a series of workshops in the summer of 2012 for the purpose of developing R&D roadmaps for enhancing the use of Nondestructive Evaluation (NDE) technologies and methodologies for detecting aging and degradation of materials and predicting the remaining useful life. The workshops were conducted to assess requirements and technical gaps related to applications of NDE for cables, concrete, reactor pressure vessels (RPV), and piping fatigue for extended reactor life. An overview of the outcomes of the workshops is presented here. Details of the workshop outcomes and proposed R&D also are available in the R&D roadmap documents cited in the bibliography and are available on the LWRS Program website (http://www.inl.gov/lwrs).

  16. Nondestructive Evaluation Techniques for Development and Characterization of Carbon Nanotube Based Superstructures

    NASA Technical Reports Server (NTRS)

    Wincheski, Buzz; Kim, Jae-Woo; Sauti, Godfrey; Wainwright, Elliot; Williams, Phillip; Siochi, Emile J.

    2014-01-01

    Recently, multiple commercial vendors have developed capability for the production of large-scale quantities of high-quality carbon nanotube sheets and yarns. While the materials have found use in electrical shielding applications, development of structural systems composed of a high volume fraction of carbon nanotubes is still lacking. A recent NASA program seeks to address this by prototyping a structural nanotube composite with strength-toweight ratio exceeding current state-of-the-art carbon fiber composites. Commercially available carbon nanotube sheets, tapes, and yarns are being processed into high volume fraction carbon nanotube-polymer nanocomposites. Nondestructive evaluation techniques have been applied throughout this development effort for material characterization and process control. This paper will report on the progress of these efforts, including magnetic characterization of residual catalyst content, Raman scattering characterization of nanotube diameter, defect ratio, and nanotube strain, and polarized Raman scattering for characterization of nanotube alignment.

  17. VibroSim: A hybrid computational/empirical model of vibrothermography nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Holland, Stephen D.; Koester, Lucas; Vaddi, Jyani; Lesthaeghe, Tyler; Meeker, William Q.; Schiefelbein, Bryan

    2016-02-01

    Vibrothermography is a nondestructive evaluation technique that finds cracks through vibration-induced heating of contacting crack surfaces. Because there are multiple phenomena involved: vibration, vibration-induced heating, and heat flow, all three processes must be accurately represented in individually tested components in order to create a meaningful model of the entire process. Finite element models are suitable for the well-understood vibrational and heat flow modeling components. With the phenomenology of the heat generation component still unclear, an empirical model was used to relate the dynamic engineering strain from the vibration to the crack heating itself. All three components are integrated into a single COMSOL model generated by a collection of MATLAB scripts.

  18. PREDICTION OF DISSOLVER LIFETIMES THROUGH NON-DESTRUCTIVE EVALUATION AND LABORATORY TESTING

    SciTech Connect

    Mickalonis, J.; Woodsmall, T.; Hinz, W.; Edwards, T.

    2011-10-03

    Non-destructive evaluation was used as the primary method of monitoring the corrosion degradation of nuclear material dissolvers and assessing the remaining lifetimes. Materials were typically processed in nitric acid based (4-14M) solutions containing fluoride concentrations less than 0.2 M. The primary corrosion issue for the stainless steel dissolvers is the occurrence of localized corrosion near the tank bottom and the heat affected zones of the welds. Laboratory data for a range of operational conditions, including solution chemistry and temperature, was used to assess the impact of processing changes on the dissolver corrosion rate. Experimental and NDE-based general corrosion rates were found to be in reasonable agreement for standard dissolution chemistries consisting of nitric acid with fluorides and at temperatures less than 95 C. Greater differences were observed when chloride was present as an impurity and temperatures exceeded 100 C.

  19. High-resolution thermal imaging methodology for non-destructive evaluation of historic structures

    NASA Astrophysics Data System (ADS)

    Hess, Michael; Vanoni, David; Petrovic, Vid; Kuester, Falko

    2015-11-01

    This paper presents a methodology for automated, portable thermography, for the acquisition of high-resolution thermal image mosaics supporting the non-destructive evaluation of historic structures. The presented approach increases the spatial resolution of thermal surveys to a level of detail needed for building scale analysis. The integration of a robotic camera platform enables automated alignment of multiple images into a high-resolution thermal image mosaic giving a holistic view of the structure while maintaining a level of detail equaling or exceeding that of traditional spot surveys using existing cameras. Providing a digital workflow for automated data and metadata recording increases the consistency and accuracy of surveys regardless of the location or operator. An imaging workflow and instrumentation are shown for a case-study on buildings in Florence, Italy demonstrating the effectiveness of this methodology for structural diagnostics.

  20. C/C composite brake disk nondestructive evaluation by IR thermography

    NASA Astrophysics Data System (ADS)

    Chu, Tsuchin P.; Poudel, Anish; Filip, Peter

    2012-06-01

    This paper discusses the non-destructive evaluation of thick Carbon/Carbon (C/C) composite aircraft brake disks by using transient infrared thermography (IRT) approach. Thermal diffusivity measurement technique was applied to identify the subsurface anomalies in thick C/C brake disks. In addition, finite element analysis (FEA) modeling tool was used to determine the transient thermal response of the C/C disks that were subjected to flash heating. For this, series of finite element models were built and thermal responses with various thermal diffusivities subjected to different heating conditions were investigated. Experiments were conducted to verify the models by using custom built in-house IRT system and commercial turnkey system. The analysis and experimental results showed good correlation between thermal diffusivity value and anomalies within the disk. It was demonstrated that the step-heating transient thermal approach could be effectively applied to obtain the whole field thermal diffusivity value of C/C composites.

  1. Nondestructive evaluation techniques for development and characterization of carbon nanotube based superstructures

    NASA Astrophysics Data System (ADS)

    Wincheski, Buzz; Kim, Jae-Woo; Sauti, Godfrey; Wainwright, Elliot; Williams, Phillip; Siochi, Emile J.

    2015-03-01

    Recently, multiple commercial vendors have developed capability for the production of large-scale quantities of high-quality carbon nanotube sheets and yarns [1]. While the materials have found use in electrical shielding applications, development of structural systems composed of a high volume fraction of carbon nanotubes is still lacking [2]. A recent NASA program seeks to address this by prototyping a structural nanotube composite with strength-to-weight ratio exceeding current state-of-the-art carbon fiber composites. Commercially available carbon nanotube sheets, tapes, and yarns are being processed into high volume fraction carbon nanotube-polymer nanocomposites. Nondestructive evaluation techniques have been applied throughout this development effort for material characterization and process control. This paper will report on the progress of these efforts, including magnetic characterization of residual catalyst content, Raman scattering characterization of nanotube diameter and nanotube strain, and polarized Raman scattering for characterization of nanotube alignment.

  2. Nondestructive Evaluation Approaches Developed for Material Characterization in Aeronautics and Space Applications

    NASA Technical Reports Server (NTRS)

    Baaklini, George Y.; Kautz, Harold E.; Gyekenyesi, Andrew L.; Abdul-Aziz, Ali; Martin, Richard E.

    2001-01-01

    At the NASA Glenn Research Center, nondestructive evaluation (NDE) approaches were developed or tailored for characterizing advanced material systems. The emphasis was on high-temperature aerospace propulsion applications. The material systems included monolithic ceramics, superalloys, and high-temperature composites. In the aeronautics area, the major applications were cooled ceramic plate structures for turbine applications, gamma-TiAl blade materials for low-pressure turbines, thermoelastic stress analysis for residual stress measurements in titanium-based and nickel-based engine materials, and acousto-ultrasonics for creep damage assessment in nickel-based alloys. In the space area, applications consisted of cooled carbon-carbon composites for gas generator combustors and flywheel rotors composed of carbon-fiber-reinforced polymer matrix composites for energy storage on the International Space Station.

  3. Evaluation of nondestructive testing techniques for the space shuttle nonmetallic thermal protection system

    NASA Technical Reports Server (NTRS)

    Tiede, D. A.

    1972-01-01

    A program was conducted to evaluate nondestructive analysis techniques for the detection of defects in rigidized surface insulation (a candidate material for the Space Shuttle thermal protection system). Uncoated, coated, and coated and bonded samples with internal defects (voids, cracks, delaminations, density variations, and moisture content), coating defects (holes, cracks, thickness variations, and loss of adhesion), and bondline defects (voids and unbonds) were inspected by X-ray radiography, acoustic, microwave, high-frequency ultrasonic, beta backscatter, thermal, holographic, and visual techniques. The detectability of each type of defect was determined for each technique (when applicable). A possible relationship between microwave reflection measurements (or X-ray-radiography density measurements) and the tensile strength was established. A possible approach for in-process inspection using a combination of X-ray radiography, acoustic, microwave, and holographic techniques was recommended.

  4. A DATA FUSION SYSTEM FOR THE NONDESTRUCTIVE EVALUATION OF NON-PIGGABLE PIPES

    SciTech Connect

    Shreekanth Mandayam; Robi Polikar; John C. Chen

    2005-02-01

    The objectives of this research project are: (1) To design sensor data fusion algorithms that can synergistically combine defect related information from heterogeneous sensors used in gas pipeline inspection for reliably and accurately predicting the condition of the pipe-wall. (2) To develop efficient data management techniques for signals obtained during multisensor interrogation of a gas pipeline. During this reporting period, Rowan University designed, developed and exercised multisensor data fusion algorithms for identifying defect related information present in magnetic flux leakage, ultrasonic testing, thermal imaging and acoustic emission nondestructive evaluation signatures of a test-specimen suite representative of benign and anomalous indications in gas transmission pipelines. Specifically, the algorithms presented in the earlier reports were augmented to predict information related to defect depth (severity).

  5. A thermal nondestructive evaluation system for detecting vertical cracks in unidirectional carbon fiber composites

    NASA Astrophysics Data System (ADS)

    Varis, J.; Lehtiniemi, R.

    1997-07-01

    A thermal system for nondestructive detection of broken fibers in unidirectional carbon fiber composites is described. The sample is heated inductively so that a line-shaped coil is scanned in the direction of the fibers. Since the thermal conductivity along the fibers is much better than in the perpendicular direction, the heat generated flows mainly in the scanning direction. Thus, the broken fibers hinder the heat flow effectively. They can be detected by monitoring the thermal radiation from the sample surface using an infrared line scanner, the image line of which is synchronized with the heating line in order to record a two-dimensional thermal image. The effect of broken fibers on the surface temperature of unidirectional carbon fiber composites is evaluated numerically and the feasibility of the system is verified experimentally.

  6. A DATA FUSION SYSTEM FOR THE NONDESTRUCTIVE EVALUATION OF NON-PIGGABLE PIPES

    SciTech Connect

    Shreekanth Mandayam; Robi Polikar; John C. Chen

    2004-04-01

    The objectives of this research project are: (1) To design sensor data fusion algorithms that can synergistically combine defect related information from heterogeneous sensors used in gas pipeline inspection for reliably and accurately predicting the condition of the pipe-wall. (2) To develop efficient data management techniques for signals obtained during multisensor interrogation of a gas pipeline. During this reporting period, Rowan University fabricated test specimens with simulated defects for nondestructive evaluation (NDE); designed and developed two versions of a test platform for performing multi-sensor interrogation of test specimens under loaded conditions simulating pressurized gas pipelines; and performed magnetic flux leakage (MFL), ultrasonic testing (UT), thermal imaging and acoustic emission (AE) NDE on the test specimens. The data resulting from this work will be employed for designing multi-sensor data fusion algorithms.

  7. Noncontact, Nondestructive Evaluation of Realistic Cracks with Surface Acoustic Waves by Scanning Excitation and Detection Lasers

    NASA Astrophysics Data System (ADS)

    Hess, P.; Lomonosov, A. M.

    2013-09-01

    Nondestructive evaluation of surface-breaking cracks with a scanning laser source, a scanning laser probe, or a scanning laser pump-probe setup is discussed. Multimode scattering of laser-excited surface acoustic wave pulses by artificial slots, realistic fatigue, or impulsive cracks is considered. This includes measuring the size of cracks in the micrometer-to-millimeter range by optical recording of the complete displacement or velocity field around the crack. Results obtained with a scanning pump-probe setup for a partially closed microcrack, generated by an elastic shock pulse in silica, are compared with those achieved with a scanning source or scanning probe for machined open notches. Crack size analysis based on the frequency spectrum of the reflected Rayleigh wave and the time lag of the transmitted Rayleigh wave is discussed. Signal enhancement effects observed in the displacement and velocity field near the crack are studied.

  8. Risk assessment of turbine rotor failure using probabilistic ultrasonic non-destructive evaluations

    SciTech Connect

    Guan, Xuefei; Zhang, Jingdan; Zhou, S. Kevin; Rasselkorde, El Mahjoub; Abbasi, Waheed A.

    2014-02-18

    The study presents a method and application of risk assessment methodology for turbine rotor fatigue failure using probabilistic ultrasonic nondestructive evaluations. A rigorous probabilistic modeling for ultrasonic flaw sizing is developed by incorporating the model-assisted probability of detection, and the probability density function (PDF) of the actual flaw size is derived. Two general scenarios, namely the ultrasonic inspection with an identified flaw indication and the ultrasonic inspection without flaw indication, are considered in the derivation. To perform estimations for fatigue reliability and remaining useful life, uncertainties from ultrasonic flaw sizing and fatigue model parameters are systematically included and quantified. The model parameter PDF is estimated using Bayesian parameter estimation and actual fatigue testing data. The overall method is demonstrated using a realistic application of steam turbine rotor, and the risk analysis under given safety criteria is provided to support maintenance planning.

  9. Evaluation and correction of readout artifacts from flat panel detectors for non-destructive testing purposes

    NASA Astrophysics Data System (ADS)

    Burtzlaff, S.; Voland, V.; Salamon, M.; Hofmann, Th.; Uhlmann, N.

    2009-08-01

    Flat panel detectors are commonly used for non-destructive testing purposes using X-ray technology. During a series of measurements with high absorbing objects, we observed an unknown kind of artifacts especially apparent with high contrast edges. These artifacts lead to unwanted results in radioscopic and computed tomography inspection. Given the object is fully occupying the lower part and half of the upper part of the detector. Looking at the image with high contrast visualization, it can be seen that the covered upper part of the detector is brighter than the covered lower half. The horizontal border of the detector tile is clearly recognizable. Furthermore, the uncovered area directly above the object is darker than next to the edge. In this area the vertical border of the edge below can be localized. We examined and evaluated the effect and developed a correction algorithm. The effect and its correction results are presented.

  10. The National Aeronautics and Space Administration Nondestructive Evaluation Program for Safe and Reliable Operations

    NASA Technical Reports Server (NTRS)

    Generazio, Ed

    2005-01-01

    The National Aeronautics and Space Administration (NASA) Nondestructive Evaluation (NDE) Program is presented. As a result of the loss of seven astronauts and the Space Shuttle Columbia on February 1, 2003, NASA has undergone many changes in its organization. NDE is one of the key areas that are recognized by the Columbia Accident Investigation Board (CAIB) that needed to be strengthened by warranting NDE as a discipline with Independent Technical Authority (iTA). The current NASA NDE system and activities are presented including the latest developments in inspection technologies being applied to the Space Transportation System (STS). The unfolding trends and directions in NDE for the future are discussed as they apply to assuring safe and reliable operations.

  11. Challenges in integrating nondestructive evaluation and finite-element methods for realistic structural analysis

    NASA Astrophysics Data System (ADS)

    Abdul-Aziz, Ali; Baaklini, George Y.; Zagidulin, Dmitri; Rauser, Richard W.

    2000-05-01

    Capabilities and expertise related to the development of links between nondestructive evaluation (NDE) and finite element analysis (FEA) at Glenn Research Center (GRC) are demonstrated. Current tools to analyze data produced by computed tomography (CT) scans are exercised to help assess the damage state in high temperature structural composite materials. A utility translator was written to convert velocity (an image processing software) STL data file to a suitable CAD-FEA type file. Finite element analyses are carried out with MARC, a commercial nonlinear finite element code, and the analytical results are discussed. Modeling was established by building MSC/Patran (a pre and post processing finite element package) generated model and comparing it to a model generated by Velocity2 in conjunction with MSC/Patran Graphics. Modeling issues and results are discussed in this paper. The entire process that outlines the tie between the data extracted via NDE and the finite element modeling and analysis is fully described.

  12. Process for Nondestructive Evaluation of the Quality of a Crimped Wire Connector

    NASA Technical Reports Server (NTRS)

    Yost, William T. (Inventor); Cramer, Karl E. (Inventor); Perey, Daniel F. (Inventor); Williams, Keith A. (Inventor)

    2014-01-01

    A process and apparatus for collecting data for nondestructive evaluation of the quality of a crimped wire connector are provided. The process involves providing a crimping tool having an anvil and opposing jaw for crimping a terminal onto a stranded wire, moving the jaw relative to the anvil to close the distance between the jaw and the anvil and thereby compress the terminal against the wire, while transmitting ultrasonic waves that are propagated through the terminal-wire combination and received at a receiving ultrasonic transducer as the jaw is moved relative to the anvil, and detecting and recording the position of the jaw relative to the anvil as a function of time and detecting and recording the amplitude of the ultrasonic wave that is received at the receiving ultrasonic transducer as a function of time as the jaw is moved relative to the anvil.

  13. Nondestructive Evaluation of the Friction Weld Process on 2195/2219 Grade Aluminum

    NASA Technical Reports Server (NTRS)

    Suits, Michael W.; Clark, Linda S.; Cox, Dwight E.

    1999-01-01

    In 1996, NASA's Marshall Space Flight Center began an ambitious program designed to find alternative methods of repairing conventional TIG (Tungsten Inert Gas) welds and VPPA (Variable Polarity Plasma Arc) welds on the Space Shuttle External Tank without producing additional heat-related anomalies or conditions. Therefore, a relatively new method, invented by The Welding Institute (TWI) in Cambridge, England, called Friction Stir Welding (FSW), was investigated for use in this application, as well as being used potentially as an initial weld process. As with the conventional repair welding processes, nondestructive evaluation (NDE) plays a crucial role in the verification of these repairs. Since it was feared that conventional NDE might have trouble with this type of weld structure (due to shape of nugget, grain structure, etc.) it was imperative that a complete study be performed to address the adequacy of the NDE process. This paper summarizes that process.

  14. Quantitative evaluation of signal integrity for magnetocardiography

    NASA Astrophysics Data System (ADS)

    Zhang, Shulin; Wang, Yongliang; Wang, Huiwu; Jiang, Shiqin; Xie, Xiaoming

    2009-08-01

    Magnetocardiography (MCG) is a non-invasive diagnostic tool used to investigate the activity of the heart. For applications in an unshielded environment, in order to extract the very weak signal of interest from the much higher background noise, dedicated hardware configuration and sophisticated signal processing techniques have been developed during the last decades. Being powerful in noise rejection, the signal processing may introduce signal distortions, if not properly designed and applied. However, there is a lack of an effective tool to quantitatively evaluate the signal integrity for MCG at present. In this paper, we have introduced a very simple method by using a small coil driven by a human ECG signal to generate a simulated MCG signal. Three key performance indexes were proposed, which are correlation in time domain, relative heights of different peaks and correlation in frequency domain, to evaluate the MCG system performance quantitatively. This evaluation method was applied to a synthetic gradiometer consisting of a second-order axial gradiometer and three orthogonal reference magnetometers. The evaluation turned out to be very effective in optimizing the parameters for signal processing. In addition, the method can serve as a useful tool for hardware improvement.

  15. Wavelet-based subsurface defect characterization in pulsed phase thermography for non-destructive evaluation

    NASA Astrophysics Data System (ADS)

    Zauner, G.; Mayr, G.; Hendorfer, G.

    2009-02-01

    Active infrared thermography is a method for non-destructive testing (NDT) of materials and components. In pulsed thermography (PT), a brief and high intensity flash is used to heat the sample. The decay of the sample surface temperature is detected and recorded by an infrared camera. Any subsurface anomaly (e.g. inclusion, delamination, etc.) gives rise to a local temperature increase (thermal contrast) on the sample surface. Conventionally, in Pulsed Phase Thermography (PPT) the analysis of PT time series is done by means of Discrete Fourier Transform producing phase images which can suppress unwanted physical effects (due to surface emissivity variations or non-uniform heating). The drawback of the Fourier-based approach is the loss of temporal information, making quantitative inversion procedures tricky (e.g. defect depth measurements). In this paper the complex Morlet-Wavelet transform is used to preserve the time information of the signal and thus provides information about the depth of a subsurface defect. Additionally, we propose to use the according phase contrast value to derive supplementary information about the thermal reflection properties at the defect interface. This provides additional information (e.g. about the thermal mismatch factor between the specimen and the defect) making interpretation of PPT results easier and perhaps unequivocal.

  16. Quantitative ultrasonic evaluation of engineering properties in metals, composites and ceramics

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1980-01-01

    Ultrasonic technology from the perspective of nondestructive evaluation approaches to material strength prediction and property verification is reviewed. Emergent advanced technology involving quantitative ultrasonic techniques for materials characterization is described. Ultrasonic methods are particularly useful in this area because they involve mechanical elastic waves that are strongly modulated by the same morphological factors that govern mechanical strength and dynamic failure processes. It is emphasized that the technology is in its infancy and that much effort is still required before all the available techniques can be transferred from laboratory to industrial environments.

  17. Nondestructive Evaluation of Advanced Materials with X-ray Phase Mapping

    NASA Technical Reports Server (NTRS)

    Hu, Zhengwei

    2005-01-01

    X-ray radiation has been widely used for imaging applications since Rontgen first discovered X-rays over a century ago. Its large penetration depth makes it ideal for the nondestructive visualization of the internal structure and/or defects of materials unobtainable otherwise. Currently used nondestructive evaluation (NDE) tools, X-ray radiography and tomography, are absorption-based, and work well in heavy-element materials where density or composition variations due to internal structure or defects are high enough to produce appreciable absorption contrast. However, in many cases where materials are light-weight and/or composites that have similar mass absorption coefficients, the conventional absorption-based X-ray methods for NDE become less useful. Indeed, the light-weight and ultra-high-strength requirements for the most advanced materials used or developed for current flight mission and future space exploration pose a great challenge to the standard NDE tools in that the absorption contrast arising from the internal structure of these materials is often too weak to be resolved. In this presentation, a solution to the problem, the use of phase information of X-rays for phase contrast X-ray imaging, will be discussed, along with a comparison between the absorption-based and phase-contrast imaging methods. Latest results on phase contrast X-ray imaging of lightweight Space Shuttle foam in 2D and 3D will be presented, demonstrating new opportunities to solve the challenging issues encountered in advanced materials development and processing.

  18. Automated Nondestructive Evaluation Method for Characterizing Ceramic and Metallic Hot Gas Filters

    SciTech Connect

    Ellingson, W.A.; Pastila, P.; Koehl, E.R.; Wheeler, B.; Deemer, C.; Forster, G.A.

    2002-09-19

    The objective of this work was to develop a nondestructive (NDE), cost-effective and reliable method to assess the condition of rigid ceramic hot gas filters. The work was intended to provide an end user, as well as filter producers, with a nondestructive method to assess the ''quality'' or status of the filters.

  19. Study on pulsed phase analysis of depth measurement for infrared thermal wave nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Li, Yan-hong; Zhao, Yue-jin; Feng, Li-chun; Zhang, Cun-lin

    2008-03-01

    Pulsed infrared thermal wave nondestructive evaluation has been widely used in various materials' R&D, quality supervise, detection and evaluation. Furthermore, based on pulse infrared thermal wave thermography experiment, a new signal analyze method called pulse phase thermography was introduced by changing the temporal signal to frequency field through Fourier transform. The pulse signal consists of various frequencies information and different thermal wave frequency reaches corresponding depth in the material. According to the relation of thermal wave's frequency to conduction depth, pulse phase thermography method can detect the depth of defects. The intuitionistic thermograph result is the phase information of each pixel in frequency field, through that the defect's size, location can be well distinguished. In order to solve the depth detection, two standard flat bottom holes samples made of aluminum and steel were studied. By analyzing the experimental results, it showed the theoretical depth value and actual depth relations, which can provide an assistant way for subsurface defects detection of material and structure. In that case, given a standard sample with artificial defects, the products made of the same material can be well detected and evaluated. At the same time, corresponding to the pulse infrared thermal wave thermography, phase thermographs with the phase information have higher sensitivity to the defects, and do not influence with the ununiformity of the light heating.

  20. Evaluation of physical dimension changes as nondestructive measurements for monitoring rigor mortis development in broiler muscles.

    PubMed

    Cavitt, L C; Sams, A R

    2003-07-01

    Studies were conducted to develop a non-destructive method for monitoring the rate of rigor mortis development in poultry and to evaluate the effectiveness of electrical stimulation (ES). In the first study, 36 male broilers in each of two trials were processed at 7 wk of age. After being bled, half of the birds received electrical stimulation (400 to 450 V, 400 to 450 mA, for seven pulses of 2 s on and 1 s off), and the other half were designated as controls. At 0.25 and 1.5 h postmortem (PM), carcasses were evaluated for the angles of the shoulder, elbow, and wing tip and the distance between the elbows. Breast fillets were harvested at 1.5 h PM (after chilling) from all carcasses. Fillet samples were excised and frozen for later measurement of pH and R-value, and the remainder of each fillet was held on ice until 24 h postmortem. Shear value and pH means were significantly lower, but R-value means were higher (P < 0.05) for the ES fillets compared to the controls, suggesting acceleration of rigor mortis by ES. The physical dimensions of the shoulder and elbow changed (P < 0.05) during rigor mortis development and with ES. These results indicate that physical measurements of the wings maybe useful as a nondestructive indicator of rigor development and for monitoring the effectiveness of ES. In the second study, 60 male broilers in each of two trials were processed at 7 wk of age. At 0.25, 1.5, 3.0, and 6.0 h PM, carcasses were evaluated for the distance between the elbows. At each time point, breast fillets were harvested from each carcass. Fillet samples were excised and frozen for later measurement of pH and sacromere length, whereas the remainder of each fillet was held on ice until 24 h PM. Shear value and pH means (P < 0.05) decreased, whereas sarcomere length means (P < 0.05) increased over time, indicating rigor mortis development. Elbow distance decreased (P < 0.05) with rigor development and was correlated (P < 0.01) with shear value (r = 0.2581), sarcomere length (r = -0.3079), and pH (r = 0.6303). These results suggest that elbow distance could be used in conjunction with other detection methods for optically automating measurement of rigor mortis development in broiler carcasses. PMID:12872980

  1. Longitudinal nondestructive evaluation of new utility wood poles. Volume 1: Final report

    SciTech Connect

    Anthony, R.W.; Bodig, J.; Phillips, G.E.; Brooks, R.T.

    1992-10-01

    This report describes the development of a nondestructive evaluation (NDE) methodology for assessing the bending strength of new wood utility poles. Fundamental concepts of stress wave propagation are presented. The development of a longitudinal stress wave methodology for predicting pole strength and the results of destructive tests on full-size poles are described. Mathematical correlations between stress wave parameters, geometric characteristics, and individual pole bending strengths form the basis of strength prediction models for western redcedar, Douglas-fir and southern pine poles. Models were developed for NDE in the whitewood stage and after preservative treatment of poles. For each species the two most commonly used preservative types were evaluated. Excellent correlations were obtained for western redcedar and Douglas-fir poles, but high moisture content in the southern pine poles resulted in lower prediction accuracies for this species. Verification of the developed mathematical models demonstrates that improvement in classifying poles into the ANSI 05.1 tip-load capacities is technically feasible. The development and field trial of the prototype equipment for strength grading of new poles is also described. Research results can be used to benefit utilities by enabling the supply of strength graded poles with a higher accuracy than previously possible.

  2. Thermo-elastic nondestructive evaluation of fatigue damage in PMR-15 resin

    NASA Astrophysics Data System (ADS)

    Welter, J. T.; Sathish, S.; Tandon, G. P.; Schehl, N.; Cherry, M.; Nalladega, V.; Lindgren, E. A.; Hall, R.

    2012-05-01

    Thermoset polyimide resins are used as the polymer matrix in high temperature composites for aerospace applications such as engine shrouds. At these locations the components have to withstand high temperatures and significant vibration. A number of studies have investigated the effects of thermal exposure on mechanical properties of polyimide resins, and the effects of fatigue on thermoplastics have been discussed at length. However, the effects of fatigue on thermosets, in particular polyimides, have largely been overlooked. In this paper we present studies of nondestructive evaluation of fatigue damage in a thermoset polyimide resin, PMR-15, performed by measuring the changes in the evolution of heat in the samples during cyclic loading. The temperature changes are measured using a high sensitivity IR camera as a function of number of fatigue cycles. Interrupted fatigue tests were performed on four samples. The temperature rise during an increment of fatigue cycling shows two linear regions each with a different slope (region 1 and region 2). Region 1 remains constant for every increment of fatigue, while region 2 increases. The onset of region 2 occurs at the same increase in temperature due to hysteretic heating for all samples. Experimental observations are explained using a phenomenological two phase model based on crosslinking density variations in observed in other thermoset resins at microscopic scales. The results of these experiments are discussed in reference to utilizing this technique for detection and evaluation of fatigue in PMR-15 resin and composites.

  3. Non-destructive evaluation of spiral-welded pipes using flexural guided waves

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaowei; Tang, Zhifeng; Lü, Fuzai; Pan, Xiaohong

    2016-02-01

    Millions of miles of pipes are being used in both civil and industrial fields. Spiral-welded pipes, which are widely applied in fields such as drainage, architecture as well as oil and gas storage and transportation, are difficult to inspect due to their complex geometry. Guided waves have shown a great potential in Non-Destructive Evaluation (NDE) and Structural Health Monitoring (SHM) for such cases. Flexural guided waves that propagate at a helix angle relative to the axial direction of pipe, are the most appropriate modes for inspecting spiral-welded pipes. The classical Normal Mode Expansion method (NME) is adopted to disseminate the forced response and perturbation analysis of a steel pipe with respect to a time delay circular loading. A time delay circular array transducer (TDCAT) is proposed for the purpose of exciting pure flexural mode in pipes. Pure flexural mode can be excited when the time delay parameter is specifically designed. The theoretical prediction is verified by finite element numerical evaluation and spiral-welded pipe inspection experiment.

  4. Non-destructive evaluation (NDE) using multi-aperture DSPI system and fast Fourier transform method

    NASA Astrophysics Data System (ADS)

    Bhaduri, Basanta; Krishna Mohan, N.; Kothiyal, M. P.

    2007-09-01

    Digital speckle pattern interferometry (DSPI) and digital shearography (DS) are two independent whole-field non-contacting optical methods for nondestructive flaw detection and precision measurements. A multi-aperture arrangement in front the imaging lens provides the grid structure within the speckles to yield desired diffraction halos at the Fourier transform plane. A three aperture arrangement in front of the imaging system is proposed here to combine coherently three waves at the CCD plane and also to introduce spatial carrier fringes within the speckle. One of the apertures is used for imaging the object onto the CCD plane, the second aperture for introducing smooth reference wave, while the third aperture carries a small angle wedge plate to provide the shear. This method allows simultaneous phase evaluation of the out-of-plane displacement and its first order derivative (slope) by filtering the appropriate diffraction halos of the Fourier spectrum. In this paper, we describe a (1, N) phase shifting technique with fast Fourier transform (FFT) for non destructive evaluation (NDE) of quasi-dynamic behavior of objects subject to slowly varying loads. The prominent advantage of the technique is that, it requires only a single frame prior to the object deformation and N number of frames during the object deformation for NDE. Experimental results are presented on a honeycomb structure subjected to thermal load.

  5. Nondestructive evaluation of fatigue damage in aluminum 2024 by x-ray diffraction

    NASA Technical Reports Server (NTRS)

    Ferguson, Milton W.

    1994-01-01

    Aluminum alloys are widely used in the automobile and aerospace industries. This is due to their attractive low density-high modulus and low density-high strength characteristics. Unfortunately, cyclic stress-strain deformations alter the microstructure of aluminum alloys when they are placed into service. These structural changes can lead to fatigue damage and ultimately service failure. Since x-ray diffraction analysis is known to be a sensitive nondestructive indicator of structural changes due to deformations, this technique is being used to evaluate changes in the microstructure of cycled aluminum 2024 commercial alloys. Line shapes, widths, and positions in an x-ray diffraction pattern depend on microstructural properties such as grain size, grain orientation, residual stress, microstrain, etc. Changes in the microstructure due to fatigue will appear as changes in the diffraction pattern. One parameter used to characterize a reflection in a diffraction pattern is the full width at half maximum (FWHM). Preliminary x-ray diffraction results on cycled Al 2024 indicate that the (111) and (222) reflections of the matrix phase do not show any variations in the FWHM due to an increase in the fatigue cycles. However, the FWHM of the (200) and (400) reflections of the same phase unexpectedly showed a dramatic decrease. These results can be interpreted as due to the relaxation of some initial nonuniform residual stresses in the matrix phase lattice. Further work is in progress to evaluate the FWHM of the second phase of the cycled alloys.

  6. Phenomenological and mechanics aspects of nondestructive evaluation and characterization by sound and ultrasound of material and fracture properties

    NASA Technical Reports Server (NTRS)

    Fu, L. S. W.

    1982-01-01

    Developments in fracture mechanics and elastic wave theory enhance the understanding of many physical phenomena in a mathematical context. Available literature in the material, and fracture characterization by NDT, and the related mathematical methods in mechanics that provide fundamental underlying principles for its interpretation and evaluation are reviewed. Information on the energy release mechanism of defects and the interaction of microstructures within the material is basic in the formulation of the mechanics problems that supply guidance for nondestructive evaluation (NDE).

  7. Nondestructive Evaluation of Stiffness and Stresses of Ceramic Candle Filters at Elevated Temperature under Vibrational Environment

    SciTech Connect

    Chen, R.H.L.; Kiriakidia, A.

    2002-09-19

    In recent years a significant amount of effort has been devoted to develop damage-tolerant hot gas filter elements, which can withstand chemical, high pressure and extreme thermal cyclic loading in the coal-based environment (Alvin 1999, Spain and Starrett 1999). Ceramic candle filters have proven to be an effective filter for the ash laden gas streams, protecting the gas turbine components from exposure to particulate matter (Lippert et al. 1994). Ceramic candle filters need to sustain extreme thermal environment and vibration-induced stresses over a great period of time. Destructive tests have been used to describe physical, mechanical and thermal properties of the filters and to relate these properties and behaviors to in-service performance, and ultimately to predict the useful life of the filter materials (Pontius and Starrett 1994, Alvin et al. 1994). Nondestructive evaluation (NDE) techniques have been developed to determine the deterioration or the presence of damage and to estimate the remaining stiffness of ceramic candle filters (Chen and Kiriakidis 2001). This paper presents a study of parameters involved in the prediction of remaining life of ceramic candle filters under service conditions. About one hundred ceramic candle filters from previous studies (Chen and Kiriakidis 2000) and forty-six filters received during this project have been nondestructively evaluated. They are divided in Pall Vitropore, Schumacher and Coors filters. Forty-six of these filters were used having various in-service exposure times at the PSDF and the rest were unused filters. Dynamic characterization tests were employed to investigate the material properties of ceramic candle filters. The vibration frequency changes due to exposure hours, dust cake accumulation, candle's axisymmetry, boundary conditions and elevated temperatures are studied. Investigations on fatigue stresses of the filters due to vibration of the plenum and back pulse shaking are also studied. Finite element models (FEM) are built to calculate the filter's dynamic response with different boundary conditions at various temperatures. The experimental natural frequencies of the candle filters were also compared with an analysis of a general Timoshenko beam equation that includes various boundary restraints.

  8. Nondestructive characterization of pipeline materials

    NASA Astrophysics Data System (ADS)

    Engle, Brady J.; Smart, Lucinda J.; Bond, Leonard J.

    2015-03-01

    There is a growing need to quantitatively and nondestructively evaluate the strength and toughness properties of pipeline steels, particularly in aging pipeline infrastructure. These strength and toughness properties, namely yield strength, tensile strength, transition temperature, and toughness, are essential for determining the safe operating pressure of the pipelines. For some older pipelines crucial information can be unknown, which makes determining the pressure rating difficult. Current inspection techniques address some of these issues, but they are not comprehensive. This paper will briefly discuss current inspection techniques and relevant literature for relating nondestructive measurements to key strength and toughness properties. A project is in progress to provide new in-trench tools that will give strength properties without the need for sample removal and destructive testing. Preliminary experimental ultrasonic methods and measurements will be presented, including velocity, attenuation, and backscatter measurements.

  9. Fast solver for large scale eddy current non-destructive evaluation problems

    NASA Astrophysics Data System (ADS)

    Lei, Naiguang

    Eddy current testing plays a very important role in non-destructive evaluations of conducting test samples. Based on Faraday's law, an alternating magnetic field source generates induced currents, called eddy currents, in an electrically conducting test specimen. The eddy currents generate induced magnetic fields that oppose the direction of the inducing magnetic field in accordance with Lenz's law. In the presence of discontinuities in material property or defects in the test specimen, the induced eddy current paths are perturbed and the associated magnetic fields can be detected by coils or magnetic field sensors, such as Hall elements or magneto-resistance sensors. Due to the complexity of the test specimen and the inspection environments, the availability of theoretical simulation models is extremely valuable for studying the basic field/flaw interactions in order to obtain a fuller understanding of non-destructive testing phenomena. Theoretical models of the forward problem are also useful for training and validation of automated defect detection systems. Theoretical models generate defect signatures that are expensive to replicate experimentally. In general, modelling methods can be classified into two categories: analytical and numerical. Although analytical approaches offer closed form solution, it is generally not possible to obtain largely due to the complex sample and defect geometries, especially in three-dimensional space. Numerical modelling has become popular with advances in computer technology and computational methods. However, due to the huge time consumption in the case of large scale problems, accelerations/fast solvers are needed to enhance numerical models. This dissertation describes a numerical simulation model for eddy current problems using finite element analysis. Validation of the accuracy of this model is demonstrated via comparison with experimental measurements of steam generator tube wall defects. These simulations generating two-dimension raster scan data typically takes one to two days on a dedicated eight-core PC. A novel direct integral solver for eddy current problems and GPU-based implementation is also investigated in this research to reduce the computational time.

  10. Nondestructive evaluation for crack, corrosion, and stress detection for metal assemblies and structures

    NASA Astrophysics Data System (ADS)

    Dudziak, Martin J.; Chervonenkis, Andre Y.; Chinarov, Vladimir

    1999-01-01

    Magneto-optic imaging based upon Faraday rotation of polarized light has been successfully applied to the problem of non-destructive testing of cracks, stress fractures, corrosion, and other surface and subsurface defects in both ferromagnetic nd nonmagnetic metal structures. Some of these applications have been successfully applied to aircraft fuselage and wing structural examination, as well as to the inspection of tanks and other low-accessibility containers. There are significant needs and opportunities for improving upon the accuracy, sensitivity, portability, and automation of such non-destructive evaluation, particularly for aircraft which are by virtue of age, design, or condition subject to dangerous metal fatigue developments in between scheduled examination. There has been a need for improvement in the basic magneto-optic sensing technology as well as in the image processing of data gathered from the sensor, and in the refinement of crack and corrosion recognition algorithms and methods that can enhance automated and assisted recognition. The current research and development program in non-destructive testing applications at MODIS Corporation has developed several innovations within these areas that enable wider application of magneto-optic imaging. These include new Fe-Ga based thin-film technology resulting in (R, Bi)3(Fe, Ga)5O12 wafers that are demonstratably more sensitive to low-strength magnetic fields. These films contain (Y, Lu, Bi)3 (Fe, Ga)5O12 composition, grown on a transparent single- crystalline substrate of Gd3 Ga5 O12 composition. Other more sensitive films and substrates have been developed as well. These films have uniaxial anisotropy due to crystallographic orientation, although with orientation films can be customized for more spatial resolution and sensitivity due to the almost uniformly planar anisotropy. The MODE sensor technology is incorporated into a modular scanning apparatus that enables the operation of several modes of inspection using replaceable video or digital still camera devices as well as variable optics for magnification. Instead of relying upon tradition eddy current technology for introducing measurable magnetic fields in the sample object being examined, the MODIS apparatus operates with a high-current, micro-burst application to the test surface. The sensitivity of the MODE Fe-Ga wafers has been demonstrated in laboratory experiments to operate with magnetic fields that are weaker than those produced by long-duration high-current eddy currents such as are presently being used in NDT applications. The coupling of higher magneto-optic sensitivity plus a reduction in the eddy current generation and heat dissipation opens a path to a number of variations and extensions of magneto-optic NDT. Algorithms and software developed by MODIS and partners for processing and analysis of the scanner output images reside on a Windows 95/NT computer and are compatible with body- wearable PC systems to enable completely hands-free, mobile inspection and data collection. The recognition algorithm are based upon standard digital image processing and neural network pattern recognition that has been successfully applied in other applications.

  11. Non-Destructive Evaluation of Wind Turbine Blades Using an Infrared Camera

    SciTech Connect

    Beattie, A.G.; Rumsey, M.

    1998-12-17

    The use of a digital infrared as a non-destructive evaluation thermography camera (NDE) tool was ex- plored in two separate wind turbine blade fatigue tests. The fwst test was a fatigue test of part of a 13.1 meter wood-epoxy-composite blade. The second test was on a 4.25 meter pultruded fiber glass blade section driven at several mechanical resonant frequencies. The digital infrared camera can produce images of either the static temperature distribution on the surface of the specimen, or the dynamic temperature distribution that is in phase with a specific frequency on a vibrating specimen. The dynamic temperature distribution (due to thermoplastic effects) gives a measure of the sum of the principal stresses at each point on the surface. In the wood- epoxy-composite blade fatigue test, the point of ultimate failure was detected long before failure occurred. The mode shapes obtained with the digital infrared camera, from the resonant blade tests, were in very good agree- ment with the finite-element calculations. In addition, the static temperature images of the resonating blade showed two areas that contained cracks. Close-up dy- namic inf%red images of these areas showed the crack structure that agreed with subsequent dye-penetrant analysis.

  12. Non-destructive Evaluation of Bonds Between Fiberglass Composite and Metal

    NASA Technical Reports Server (NTRS)

    Zhao, Selina; Sonta, Kestutis; Perey, Daniel F.; Cramer, K. E.; Berger, Libby

    2015-01-01

    To assess the integrity and reliability of an adhesive joint in an automotive composite component, several non-destructive evaluation (NDE) methodologies are correlated to lap shear bond strengths. A glass-fabric-reinforced composite structure was bonded to a metallic structure with a two-part epoxy adhesive. Samples were subsequently cut and tested in shear, and flaws were found in some areas. This study aims to develop a reliable and portable NDE system for service-level adhesive inspection in the automotive industry. The results of the experimental investigation using several NDE methods are presented and discussed. Fiberglass-to-metal bonding is the ideal configuration for NDE via thermography using excitation with induction heating, due to the conductive metal and non-conductive glass-fiber-reinforced composites. Excitation can be either by a research-grade induction heater of highly defined frequency and intensity, or by a service-level heater, such as would be used for sealing windshields in a body shop. The thermographs thus produced can be captured via a high-resolution infrared camera, with principal component analysis and 2D spatial Laplacian processing. Alternatively, the thermographs can be captured by low resolution thermochromic microencapsulated liquid crystal film imaging, which needs no post-processing and can be very inexpensive. These samples were also examined with phased-array ultrasound. The NDE methods are compared to the lap shear values and to each other for approximate cost, accuracy, and time and level of expertise needed.

  13. Evaluation of scanners for C-scan imaging in nondestructive inspection of aircraft

    SciTech Connect

    Gieske, J.H.

    1994-04-01

    The goal of this project was to produce a document that contains information on the usability and performance of commercially available, fieldable, and portable scanner systems as they apply to aircraft NDI inspections. In particular, the scanners are used to generate images of eddy current, ultrasonic, or bond tester inspection data. The scanner designs include manual scanners, semiautomated scanners, and fully automated scanners. A brief description of the functionality of each scanner type, a sketch, and a fist of the companies that support the particular design are provided. Vendors of each scanner type provided hands-on demonstrations of their equipment on real aircraft samples in the FAA Aging Aircraft Nondestructive Inspection Validation Center (AANC) in Albuquerque, NM. From evaluations recorded during the demonstrations, a matrix of scanner features and factors and ranking of the capabilities and limitations of the design, portability, articulation, performance, usability, and computer hardware/software was constructed to provide a quick reference for comparing the different scanner types. Illustrations of C-scan images obtained during the demonstration are shown.

  14. Interrelationship of Nondestructive Evaluation Methodologies Applied to Testing of Composite Overwrapped Pressure Vessels

    NASA Technical Reports Server (NTRS)

    Leifeste, Mark R.

    2007-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are commonly used in spacecraft for containment of pressurized gases and fluids, incorporating strength and weight savings. The energy stored is capable of extensive spacecraft damage and personal injury in the event of sudden failure. These apparently simple structures, composed of a metallic media impermeable liner and fiber/resin composite overwrap are really complex structures with numerous material and structural phenomena interacting during pressurized use which requires multiple, interrelated monitoring methodologies to monitor and understand subtle changes critical to safe use. Testing of COPVs at NASA Johnson Space Center White Sands T est Facility (WSTF) has employed multiple in-situ, real-time nondestructive evaluation (NDE) methodologies as well as pre- and post-test comparative techniques to monitor changes in material and structural parameters during advanced pressurized testing. The use of NDE methodologies and their relationship to monitoring changes is discussed based on testing of real-world spacecraft COPVs. Lessons learned are used to present recommendations for use in testing, as well as a discussion of potential applications to vessel health monitoring in future applications.

  15. Method and apparatus for enhancing surface absorption and emissivity in optical pulsed infrared nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Duan, Yuxia; Zhang, Cunlin; Jin, Wanping; Wu, Naiming

    2009-07-01

    In the application of optical pulsed infrared NDE, the visible light absorption and IR emissivity of the detected object must be considered. One of the simple methods is spraying paint on the highly reflective and low IR emissivity surface before testing. However, for some materials such as with pore space in the surface or easily to be corrupted have to be pretreated by other method and apparatus. Two kinds of apparatus for surface pretreating are designed according to the dimension of the detected object and the testing conditions. One apparatus is independent of the former detecting system, and the other is an improvement of the former system. The basic principle of the two apparatus is covering a flexible membrane of high light absorption and IR emissivity on the specimen surface by vacuum pumping. The paper also present the applications of the method, including the detection of the metal mesh material and the honeycomb structures with aluminum coating. The experimental results show that the technique of covering thin film by vacuum pump is effective for enhancing surface absorption and emissivity; moreover, it does not pollute or damage the sample. The application of the technique has practical significance, because it extends the scope of the application of the optical pulsed thermography nondestructive evaluation.

  16. Laser Doppler technique for nondestructive evaluation of mechanical heart valves kinematics

    NASA Astrophysics Data System (ADS)

    Grigioni, Mauro; Daniele, Carla; Morbiducci, U.; Del Gaudio, C.; D'Avenio, Giuseppe; Di Meo, D.; Barbaro, Vincenzo

    2004-06-01

    Laser techniques for vibration measurement, due to their non-contact nature, represents an interesting alternative investigational tool to be tested in biomedical and clinic fields. A particular application could be as evaluation method in design and quality control of artificial organs. Aim of this study is to investigate the application of laser vibrometry to the study of mechanical heart valves in-vitro, with an ad hoc set-up. A heterodyne laser Doppler vibrometry system, which allows the measurement of both vibrational velocity and displacement was used. Three different approaches have been carried out, in order to stress the limits of the laser vibrometry technique for testing heart valve prostheses. Critical points and difficulties to build up experimental studies in this field were clearly pointed out. In the present study only one laser head was used, the aim of the authors being to test the feasibility of a simplified approach on mechanical cardiac valves. Starting from that analysis a comparison could be made to assess the capability to discriminate between normal and malfunctioning devices. The advantage of the proposed test bench is that it could provide a non-contact, non-destructive analysis of the valve under the same working conditions as those upon implantation. The proposed method could furnish a typical "fingerprint" characterizing each valve behavior in repeatable experimental conditions.

  17. Detection of thermally grown oxides in thermal barrier coatings by nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Fahr, A.; Rog, B.; Thornton, J.

    2006-03-01

    The thermal-barrier coatings (TBC) sprayed on hot-section components of aircraft turbine engines commonly consist of a partially stabilized zirconia top-coat and an intermediate bond-coat applied on the metallic substrate. The bond-coat is made of an aluminide alloy that at high engine temperatures forms thermally grown oxides (TGO). Although formation of a thin layer of aluminum oxide at the interface between the ceramic top-coat and the bond-coat has the beneficial effect of protecting the metallic substrate from hot gases, oxide formation at splat boundaries or pores within the bond-coat is a source of weakness. In this study, plasma-sprayed TBC specimens are manufactured from two types of bond-coat powders and exposed to elevated temperatures to form oxides at the ceramic-bond-coat boundary and within the bond-coat. The specimens are then tested using nondestructive evaluation (NDE) and destructive metallography and compared with the as-manufactured samples. The objective is to determine if NDE can identify the oxidation within the bond-coat and give indication of its severity. While ultrasonic testing can provide some indication of the degree of bond-coat oxidation, the eddy current (EC) technique clearly identifies severe oxide formation within the bond-coat. Imaging of the EC signals as the function of probe location provides information on the spatial variations in the degree of oxidation, and thereby identifies which components or areas are prone to premature damage.

  18. Modal Test Technology as Non-Destructive Evaluation of Space Shuttle Structures

    NASA Technical Reports Server (NTRS)

    Grygler, Micheal S.

    1994-01-01

    Modal test and analysis Is being used for nondestructive evaluation of Space Shuttle structures. The purpose of modal testing is to measure the dynamic characteristics of a structure to extract its resonance frequencies, damping, and mode shapes. These characteristics are later compared to subsequently acquired characteristics. Changes in the modal characteristics indicate damage in the structure. Use of modal test technology as a damage detection tool was developed at JSC during the Shuttle acoustic certification program and subsequent test programs. The Shuttle Modal Inspection System was created in order to inspect areas that are impossible or impractical to inspect with conventional methods. Areas on which this technique has been applied include control surfaces, which are covered with thermal protection tiles, and the Forward Reaction Control Module, which is a frame structure that supports various tanks, thrusters, and fluid lines, which requires major disassembly to inspect. This paper traces the development of the technology, gives a status of its implementation on the Shuttle, explains challenges involved in implementing this type of inspection program, and suggests future improvements in data analysis and interpretation. Dual-use applications of the technology include inspections of bridges, oil-platforms, and aircraft.

  19. PHOTOACOUSTIC NON-DESTRUCTIVE EVALUATION AND IMAGING OF CARIES IN DENTAL SAMPLES

    SciTech Connect

    Li, T.; Dewhurst, R. J.

    2010-02-22

    Dental caries is a disease wherein bacterial processes damage hard tooth structure. Traditional dental radiography has its limitations for detecting early stage caries. In this study, a photoacoustic (PA) imaging system with the near-infrared light source has been applied to postmortem dental samples to obtain 2-D and 3-D images. Imaging results showed that the PA technique can be used to image human teeth caries. For non-destructive photoacoustic evaluation and imaging, the induced temperature and pressure rises within biotissues should not cause physical damage to the tissue. For example, temperature rises above 5 deg. C within live human teeth will cause pulpal necrosis. Therefore, several simulations based on the thermoelastic effect have been applied to predict temperature and pressure fields within samples. Predicted temperature levels are below corresponding safety limits, but care is required to avoid nonlinear absorption phenomena. Furthermore, PA imaging results from the phantom provide evidence for high sensitivity, which shows the imaging potential of the PA technique for detecting early stage disease.

  20. Two-dimensional virtual array for ultrasonic nondestructive evaluation using a time-reversal chaotic cavity.

    PubMed

    Choi, Youngsoo; Lee, Hunki; Hong, Hyun; Ohm, Won-Suk

    2011-11-01

    Despite its introduction more than a decade ago, a two-dimensional ultrasonic array remains a luxury in nondestructive evaluation because of the complexity and cost associated with its fabrication and operation. This paper describes the construction and performance of a two-dimensional virtual array that solves these problems. The virtual array consists of only two transducers (one each for transmit and receive) and an aluminum chaotic cavity, augmented by a 10  ×  10 matrix array of rectangular rods. Each rod, serving as an elastic waveguide, is calibrated to emit a collimated pulsed sound beam centered at 2.5 MHz using the reciprocal time reversal. The resulting virtual array is capable of pulse-echo interrogation of a solid sample in direct contact along 10  ×  10 scan lines. Three-dimensional imaging of an aluminum test piece, the nominal thickness of which is in the order of 1 cm, is successfully carried out using the virtual array. PMID:22087900

  1. An Analysis of Nondestructive Evaluation Techniques for Polymer Matrix Composite Sandwich Materials

    NASA Technical Reports Server (NTRS)

    Cosgriff, Laura M.; Roberts, Gary D.; Binienda, Wieslaw K.; Zheng, Diahua; Averbeck, Timothy; Roth, Donald J.; Jeanneau, Philippe

    2006-01-01

    Structural sandwich materials composed of triaxially braided polymer matrix composite material face sheets sandwiching a foam core are being utilized for applications including aerospace components and recreational equipment. Since full scale components are being made from these sandwich materials, it is necessary to develop proper inspection practices for their manufacture and in-field use. Specifically, nondestructive evaluation (NDE) techniques need to be investigated for analysis of components made from these materials. Hockey blades made from sandwich materials and a flat sandwich sample were examined with multiple NDE techniques including thermographic, radiographic, and shearographic methods to investigate damage induced in the blades and flat panel components. Hockey blades used during actual play and a flat polymer matrix composite sandwich sample with damage inserted into the foam core were investigated with each technique. NDE images from the samples were presented and discussed. Structural elements within each blade were observed with radiographic imaging. Damaged regions and some structural elements of the hockey blades were identified with thermographic imaging. Structural elements, damaged regions, and other material variations were detected in the hockey blades with shearography. Each technique s advantages and disadvantages were considered in making recommendations for inspection of components made from these types of materials.

  2. Automated nondestructive evaluation method for characterizing ceramic and metallic hot gas filters.

    SciTech Connect

    Ellingson, W. A.; Koehl, E. R.; Deemer, C.; Pastilla, P.; Wheeler, B.; Forster, G. A.

    2002-06-03

    In advanced coal-fired power generation, one technology under development to clean up hot gases before their use as fuel for gas turbines is rigid ceramic candle filters. These porous filters are typically 1.5 m long and 60 mm in diameter and are made of various ceramic materials, including clay-bonded SiC. The high costs of downtime in a large utility demands that nondestructive evaluation/characterization (NDE/C) methods be available. At shutdowns, data from such analysis are needed to decide which filters are still usable and which need to be replaced, and if possible, to estimate the remaining lifetimes. Thus our objective was to develop reliable low-cost NDE technology for these filters. Our approach was to develop NDE/C technology, referred to as acousto-ultrasonics (AU), for application to hot gas filters. Lamb waves generated by the AU method were analyzed to derive a stress wave factor (SWF). This technology was tested by comparing SWF data with the measured strength for a variety of rigid ceramic filters and was shown to work on iron-aluminide filters as well but no strength data have been obtained on the iron-aluminides at this time.

  3. Non-Destructive Evaluation of Historical Paper Based on pH Estimation from VOC Emissions

    PubMed Central

    Strlič, Matija; Cigić, Irena Kralj; Kolar, Jana; de Bruin, Gerrit; Pihlar, Boris

    2007-01-01

    Volatile organic compounds (VOCs) emitted from materials during degradation can be a valuable source of information. In this work, the emissions of furfural and acetic acid from cellulose were studied using solid-phase micro-extraction (SPME) in combination with gas chromatography-mass spectrometry. Two sampling techniques were employed: static headspace sampling using SPME for 1 h at 40 °C after 18-h sample preparation at 80 °C in a closed glass vial, and contact SPME in a stack of paper (or a book). While a number of VOCs are emitted from paper under conditions of natural or accelerated degradation, two compounds were confirmed to be of particular diagnostic value: acetic acid and furfural. The emissions of furfural are shown to correlate with pH of the cellulosic environment. Since pH is one of the most important parameters regarding durability of this material, the developed method could be used for non-destructive evaluation of historical paper.

  4. A multi-inspection non-destructive testing method for quality evaluation of composite riveted structure

    NASA Astrophysics Data System (ADS)

    Wang, Weihan; He, Jingjing; Yang, Jingsong; Liu, Shengwang; Zhang, Weifang

    2015-03-01

    Carbon fiber composites have excellent mechanical properties, which are widely used in aerospace industry. However, 60% to 80% damages in composite occur in riveted structures. This research focuses on the quality evaluation of three major riveted structures used in mechanical connection: pressure riveted connection, hammer riveted connection and pull riveted connection. The non-destructive testing results show that the pull riveting technology introduces minimal damage to the composite, but the hammer riveted structure can be seriously damaged by the riveting technology. The pull riveted structure is an interference fit, which makes the composite plate firmly fixed. However, the fix is weak in the pressure riveted structure and the hammer riveted structure, due to the small gap between the rivets and plate. The results show that the pull riveted structure has a higher tensile strength compared with the pressure riveted structure and hammer riveted structure. The hammer riveted structure has a large dispersion in mechanical properties caused by the impact loading used in the hammer riveting technology.

  5. Solution of Boundary Integral Equations for Eddy Current Nondestructive Evaluation in Three Dimensions

    NASA Astrophysics Data System (ADS)

    Yang, Ming; Song, Jiming; Nakagawa, Norio

    2009-03-01

    Eddy current nondestructive evaluation (NDE) of airframe structures involves the detection of electromagnetic field irregularities due to non-conducting inhomogeneities in an electrically conducting material, which often treats with complicated geometrical features such as cracks, fasteners, sharp corners/edges, multi-layered structures, etc. The eddy-current problem can be formulated by the boundary integral equations (BIE) and discretized into matrix equations by the method of moments (MoM) or the boundary element method (BEM). This paper introduces the implementation of Stratton-Chu formulation for the conductive medium, in which the induced electric and magnetic surface currents are expanded in terms of Rao-Wilton-Glisson (RWG) vector basis function and the normal component of magnetic field is expanded in terms of pulse basis function. Also, a low frequency approximation is applied in the external medium, that is, free space in our case. Computational tests are presented to demonstrate the accuracy and capability of the BIE method with a complex wave number for three-dimensional objects described by a number of triangular patches. This work prepares the BIE solution procedure that will be embedded with the Fast Multipole Method (FMM), which is a well-established and effective method for accelerating numerical solutions of the matrix equations. When accelerated by the FMM, the BIE method will have the capability of solving large-scale electromagnetic wave propagation and eddy-current problems.

  6. Nondestructive Evaluation (NDE) for Characterizing Oxidation Damage in Cracked Reinforced Carbon-Carbon

    NASA Technical Reports Server (NTRS)

    Roth, Don J.; Jacobson, Nathan S.; Rauser, Richard W.; Wincheski, Russell A.; Walker, James L.; Cosgriff, Laura A.

    2010-01-01

    In this study, coated reinforced carbon-carbon (RCC) samples of similar structure and composition as that from the NASA space shuttle orbiter's thermal protection system were fabricated with slots in their coating simulating craze cracks. These specimens were used to study oxidation damage detection and characterization using nondestructive evaluation (NDE) methods. These specimens were heat treated in air at 1143 C and 1200 C to create cavities in the carbon substrate underneath the coating as oxygen reacted with the carbon and resulted in its consumption. The cavities varied in diameter from approximately 1 to 3mm. Single-sided NDE methods were used because they might be practical for on-wing inspection, while X-ray micro-computed tomography (CT) was used to measure cavity sizes in order to validate oxidation models under development for carbon-carbon materials. An RCC sample having a naturally cracked coating and subsequent oxidation damage was also studied with X-ray micro-CT. This effort is a follow-on study to one that characterized NDE methods for assessing oxidation damage in an RCC sample with drilled holes in the coating.

  7. Nondestructive Evaluation (NDE) for Characterizing Oxidation Damage in Cracked Reinforced Carbon-Carbon (RCC)

    NASA Technical Reports Server (NTRS)

    Roth, Don J.; Rauser, Richard W.; Jacobson, Nathan S.; Wincheski, Russell A.; Walker, James L.; Cosgriff, Laura A.

    2009-01-01

    In this study, coated reinforced carbon-carbon (RCC) samples of similar structure and composition as that from the NASA space shuttle orbiter's thermal protection system were fabricated with slots in their coating simulating craze cracks. These specimens were used to study oxidation damage detection and characterization using nondestructive evaluation (NDE) methods. These specimens were heat treated in air at 1143 and 1200 C to create cavities in the carbon substrate underneath the coating as oxygen reacted with the carbon and resulted in its consumption. The cavities varied in diameter from approximately 1 to 3 mm. Single-sided NDE methods were used since they might be practical for on-wing inspection, while x-ray micro-computed tomography (CT) was used to measure cavity sizes in order to validate oxidation models under development for carbon-carbon materials. An RCC sample having a naturally-cracked coating and subsequent oxidation damage was also studied with x-ray micro-CT. This effort is a follow-on study to one that characterized NDE methods for assessing oxidation damage in an RCC sample with drilled holes in the coating.

  8. Development of Natural Flaw Samples for Evaluating Nondestructive Testing Methods for Foam Thermal Protection Systems

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Davis, Jason; Farrington, Seth; Walker, James

    2007-01-01

    Low density polyurethane foam has been an important insulation material for space launch vehicles for several decades. The potential for damage from foam breaking away from the NASA External Tank was not realized until the foam impacts on the Columbia Orbiter vehicle caused damage to its Leading Edge thermal protection systems (TPS). Development of improved inspection techniques on the foam TPS is necessary to prevent similar occurrences in the future. Foamed panels with drilled holes for volumetric flaws and Teflon inserts to simulate debonded conditions have been used to evaluate and calibrate nondestructive testing (NDT) methods. Unfortunately the symmetric edges and dissimilar materials used in the preparation of these simulated flaws provide an artificially large signal while very little signal is generated from the actual defects themselves. In other words, the same signal are not generated from the artificial defects in the foam test panels as produced when inspecting natural defect in the ET foam TPS. A project to create more realistic voids similar to what actually occurs during manufacturing operations was began in order to improve detection of critical voids during inspections. This presentation describes approaches taken to create more natural voids in foam TPS in order to provide a more realistic evaluation of what the NDT methods can detect. These flaw creation techniques were developed with both sprayed foam and poured foam used for insulation on the External Tank. Test panels with simulated defects have been used to evaluate NDT methods for the inspection of the External Tank. A comparison of images between natural flaws and machined flaws generated from backscatter x-ray radiography, x-ray laminography, terahertz imaging and millimeter wave imaging show significant differences in identifying defect regions.

  9. Acousto-ultrasonic nondestructive evaluation of materials using laser beam generation and detection. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Huber, Robert D.; Green, Robert E., Jr.

    1990-01-01

    The acousto-ultrasonic method has proven to be a most interesting technique for nondestructive evaluation of the mechanical properties of a variety of materials. Use of the technique or a modification thereof, has led to correlation of the associated stress wave factor with mechanical properties of both metals and composite materials. The method is applied to the nondestructive evaluation of selected fiber reinforced structural composites. For the first time, conventional piezoelectric transducers were replaced with laser beam ultrasonic generators and detectors. This modification permitted true non-contact acousto-ultrasonic measurements to be made, which yielded new information about the basic mechanisms involved as well as proved the feasibility of making such non-contact measurements on terrestrial and space structures and heat engine components. A state-of-the-art laser based acousto-ultrasonic system, incorporating a compact pulsed laser and a fiber-optic heterodyne interferometer, was delivered to the NASA Lewis Research Center.

  10. Dynamic laser speckle for non-destructive quality evaluation of bread

    NASA Astrophysics Data System (ADS)

    Stoykova, E.; Ivanov, B.; Shopova, M.; Lyubenova, T.; Panchev, I.; Sainov, V.

    2010-10-01

    Coherent illumination of a diffuse object yields a randomly varying interference pattern, which changes over time at any modification of the object. This phenomenon can be used for detection and visualization of physical or biological activity in various objects (e.g. fruits, seeds, coatings) through statistical description of laser speckle dynamics. The present report aims at non-destructive full-field evaluation of bread by spatial-temporal characterization of laser speckle. The main purpose of the conducted experiments was to prove the ability of the dynamic speckle method to indicate activity within the studied bread samples. In the set-up for acquisition and storage of dynamic speckle patterns an expanded beam from a DPSS laser (532 nm and 100mW) illuminated the sample through a ground glass diffuser. A CCD camera, adjusted to focus the sample, recorded regularly a sequence of images (8 bits and 780 x 582 squared pixels, sized 8.1 × 8.1 μm) at sampling frequency 0.25 Hz. A temporal structure function was calculated to evaluate activity of the bread samples in time using the full images in the sequence. In total, 7 samples of two types of bread were monitored during a chemical and physical process of bread's staling. Segmentation of images into matrixes of isometric fragments was also utilized. The results proved the potential of dynamic speckle as effective means for monitoring the process of bread staling and ability of this approach to differentiate between different types of bread.

  11. Quantitative evaluation of gait ataxia by accelerometers.

    PubMed

    Shirai, Shinichi; Yabe, Ichiro; Matsushima, Masaaki; Ito, Yoichi M; Yoneyama, Mitsuru; Sasaki, Hidenao

    2015-11-15

    An appropriate biomarker for spinocerebellar degeneration (SCD) has not been identified. Here, we performed gait analysis on patients with pure cerebellar type SCD and assessed whether the obtained data could be used as a neurophysiological biomarker for cerebellar ataxia. We analyzed 25 SCD patients, 25 patients with Parkinson's disease as a disease control, and 25 healthy control individuals. Acceleration signals during 6 min of walking and 1 min of standing were measured by two sets of triaxial accelerometers that were secured with a fixation vest to the middle of the lower and upper back of each subject. We extracted two gait parameters, the average and the coefficient of variation of motion trajectory amplitude, from each acceleration component. Then, each component was analyzed by correlation with the Scale for the Assessment and Rating of Ataxia (SARA) and the Berg Balance Scale (BBS). Compared with the gait control of healthy subjects and concerning correlation with severity and disease specificity, our results suggest that the average amplitude of medial-lateral (upper back) of straight gait is a physiological biomarker for cerebellar ataxia. Our results suggest that gait analysis is a quantitative and concise evaluation scale for the severity of cerebellar ataxia. PMID:26362336

  12. Nondestructive Evaluation of Adhesively Bonded Joints by Acousto-Ultrasonic Technique and Acoustic Emission

    NASA Technical Reports Server (NTRS)

    Nayeb-Hashemi, Hamid; Rossettos, J. N.

    1997-01-01

    Reliable applications of adhesively bonded joints require an effective nondestructive evaluation technique for their bond strength prediction. To properly evaluate factors affecting bond strength, effects of defects such as voids and disbonds on stress distribution in the overlap region must be understood. At the same time, in order to use acousto-ultrasonic (AU) technique to evaluate bond quality, the effect of these defects on dynamic response of single lap joints must be clear. The stress distribution in a single lap joint with and without defects (void or disbond) is analyzed. A bar-Theta parameter which contains adherend and adhesive thickness and properties is introduced. It is shown for bonded joints with bar-Theta greater than 10, that a symmetric void or disbond in the middle of overlap up to the 70 percent of overlap length has negligible effect on bond strength. In contrast frequency response analyses by a finite element technique showed that the dynamic response is affected significantly by the presence of voids or disbonds. These results have direct implication in the interpretations of AU results. Through transmission attenuation and a number of AU parameters for various specimens with and without defects are evaluated. It is found that although void and disbond have similar effects on bond strength (stress distribution), they have completely different effects on wave propagation characteristics. For steel-adhesive-steel specimens with voids, the attenuation changes are related to the bond strength. However, the attenuation changes for specimens with disbond are fairly constant over a disbond range. In order to incorporate the location of defects in AU parameters, a weighting function is introduced. Using an immersion system with focused transducers, a number of AU parameters are evaluated. It is found that by incorporating weighting functions in these parameters better sensitivities (AU parameters vs. bond strength) are achieved. Acoustic emission (AE) activities of steel-adhesive-steel specimens with bar-Theta equal to 3.4 are monitored. Two different formats of energy vs. time have resulted, each corresponding to the perfect specimens or the specimens with void or disbond. The relative acoustic energy and the number of events at failure are found to be a means for predicting the bond strength.

  13. Quantitative Ultrasonic Evaluation of Mechanical Properties of Engineering Materials

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1978-01-01

    Progress in the application of ultrasonic techniques to nondestructive measurement of mechanical strength of engineering materials is reviewed. A dormant concept in nondestructive evaluation (NDE) is invoked. The availability of ultrasonic methods that can be applied to actual parts to assess their potential susceptibility to failure under design conditions is discussed. It was shown that ultrasonic methods yield measurements of elastic moduli, microstructure, hardness, fracture toughness, tensile strength, yield strength, and shear strength for a wide range of materials (including many types of metals, ceramics, and fiber composites). It was also indicated that although most of these methods were shown feasible in laboratory studies, more work is needed before they can be used on actual parts in processing, assembly, inspection, and maintenance lines.

  14. Non-destructive microwave evaluation of TBC delamination induced by acute angle laser drilling

    NASA Astrophysics Data System (ADS)

    Sezer, H. K.; Li, Lin; Wu, Z.; Anderson, B.; Williams, P.

    2007-01-01

    Laser drilling has been applied to the production of cooling holes of various size and angles in the modern aerospace gas turbine components such as turbine blades, nozzle guide vanes, combustion chambers and afterburner. These parts are usually made of heat resistant nickel superalloys. The superalloy substrate is coated with yttria-stabilized zirconia thermal barrier coatings (TBCs) to protect them from reaching excessive temperatures in hot engine environments. Drilling the parts at acute angles to the surface is complicated because (i) multiple layers are being drilled through, (ii) the melt ejection and heat flow patterns around the hole are non-symmetrical and (iii) the drilling distance is greater than when drilling normal to the surface. In a previous investigation by the authors, delamination of TBC was addressed as a main problem of angled drilling and mechanisms involved were discussed. Characterization of delamination cracks was normally performed via metallographic techniques. It involves sectioning the samples using an abrasive cutting machine, grinding with successively finer silicon carbide paper up to the centre of the hole and polishing to allow optical microscopic analysis of the cracks. However, clamping and sectioning process of thermal-spray-coated workpieces can introduce cracks in brittle coatings due to the drag of the cut-off wheels. Hence, it is not possible to decide if the delamination is caused as a result of post-process sectioning or laser drilling. In this paper, a microwave non-destructive testing (NDT) technique is employed to evaluate the integrity of TBC after acute angle laser drilling. An Agilent 8510 XF network analyser operating over the frequency range of 45 MHz to 110 GHz was used to measure the amplitude and phase variations of scattered waves. The results significantly indicated the existence of delamination of 1-1.5 mm long at the TBC/substrate interface on the leading edge part of an acute-angled hole laser drilled using a 400 W Nd:YAG laser.

  15. Microwave and Millimeter Wave Nondestructive Evaluation of the Space Shuttle External Tank Insulating Foam

    NASA Technical Reports Server (NTRS)

    Shrestha, S.; Kharkovsky, S.; Zoughi, R.; Hepburn, F

    2005-01-01

    The Space Shuttle Columbia s catastrophic failure has been attributed to a piece of external fuel tank insulating SOFI (Spray On Foam Insulation) foam striking the leading edge of the left wing of the orbiter causing significant damage to some of the protecting heat tiles. The accident emphasizes the growing need to develop effective, robust and life-cycle oriented methods of nondestructive testing and evaluation (NDT&E) of complex conductor-backed insulating foam and protective acreage heat tiles used in the space shuttle fleet and in future multi-launch space vehicles. The insulating SOFI foam is constructed from closed-cell foam. In the microwave regime this foam is in the family of low permittivity and low loss dielectric materials. Near-field microwave and millimeter wave NDT methods were one of the techniques chosen for this purpose. To this end several flat and thick SOFI foam panels, two structurally complex panels similar to the external fuel tank and a "blind" panel were used in this investigation. Several anomalies such as voids and disbonds were embedded in these panels at various locations. The location and properties of the embedded anomalies in the "blind" panel were not disclosed to the investigating team prior to the investigation. Three frequency bands were used in this investigation covering a frequency range of 8-75 GHz. Moreover, the influence of signal polarization was also investigated. Overall the results of this investigation were very promising for detecting the presence of anomalies in different panels covered with relatively thick insulating SOFI foam. Different types of anomalies were detected in foam up to 9 in thick. Many of the anomalies in the more complex panels were also detected. When investigating the blind panel no false positives were detected. Anomalies in between and underneath bolt heads were not easily detected. This paper presents the results of this investigation along with a discussion of the capabilities of the method used.

  16. Non-Destructive Evaluation of Kissing Bonds using Local Defect Resonance (LDR) Spectroscopy: A Simulation Study

    NASA Astrophysics Data System (ADS)

    Delrue, S.; Tabatabaeipour, M.; Hettler, J.; Van Den Abeele, K.

    With the growing demand from industry to optimize and further develop existing Non-Destructive Testing & Evaluation (NDT&E) techniques or new methods to detect and characterize incipient damage with high sensitivity and increased quality, ample efforts have been devoted to better understand the typical behavior of kissing bonds, such as delaminations and cracks. Recently, it has been shown experimentally that the nonlinear ultrasonic response of kissing bonds could be enhanced by using Local Defect Resonance (LDR) spectroscopy. LDR spectroscopy is an efficient NDT technique that takes advantage of the characteristic fre- quencies of the defect (defect resonances) in order to provide maximum acoustic wave-defect interaction. In fact, for nonlinear methodologies, the ultrasonic excitation of the sample should occur at either multiples or integer ratios of the characteristic defect resonance frequencies, in order to obtain the highest signal-to-noise response in the nonlinear LDR spectroscopy. In this paper, the potential of using LDR spectroscopy for the detection, localization and characterization of kissing bonds is illustrated using a 3D simulation code for elastic wave propagation in materials containing closed but dynamically active cracks or delaminations. Using the model, we are able to define an appropriate method, based on the Scaling Subtraction Method (SSM), to determine the local defect resonance frequencies of a delamination in a composite plate and to illustrate an increase in defect nonlinearity due to LDR. The simulation results will help us to obtain a better understanding of the concept of LDR and to assist in the further design and testing of LDR spectroscopy for the detection, localization and characterization of kissing bonds.

  17. Low-Cost Quality Control and Nondestructive Evaluation Technologies for General Aviation Structures

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott; Gavinsky, Bob; Semanskee, Grant

    1998-01-01

    NASA's Advanced General Aviation Transport Experiments (AGATE) Program has as a goal to reduce the overall cost of producing private aviation aircraft while maintaining the safety of these aircraft. In order to successfully meet this goal, it is necessary to develop nondestructive inspection techniques which will facilitate the production of the materials used in these aircraft and assure the quality necessary to maintain airworthiness. This paper will discuss a particular class of general aviation materials and several nondestructive inspection techniques that have proven effective for making these inspections. Additionally, this paper will discuss the investigation and application of other commercially available quality control techniques applicable to these structures.

  18. APNEA/WIT system nondestructive assay capability evaluation plan for select accessibly stored INEL RWMC waste forms

    SciTech Connect

    Becker, G.K.

    1997-01-01

    Bio-Imaging Research Inc. (BIR) and Lockheed Martin Speciality Components (LMSC) are engaged in a Program Research and Development Agreement and a Rapid Commercialization Initiative with the Department of Energy, EM-50. The agreement required BIR and LMSC to develop a data interpretation method that merges nondestructive assay and nondestructive examination (NDA/NDE) data and information sufficient to establish compliance with applicable National TRU Program (Program) waste characterization requirements and associated quality assurance performance criteria. This effort required an objective demonstration of the BIR and LMSC waste characterization systems in their standalone and integrated configurations. The goal of the test plan is to provide a mechanism from which evidence can be derived to substantiate nondestructive assay capability and utility statement for the BIT and LMSC systems. The plan must provide for the acquisition, compilation, and reporting of performance data thereby allowing external independent agencies a basis for an objective evaluation of the standalone BIR and LMSC measurement systems, WIT and APNEA respectively, as well as an expected performance resulting from appropriate integration of the two systems. The evaluation is to be structured such that a statement regarding select INEL RWMC waste forms can be made in terms of compliance with applicable Program requirements and criteria.

  19. Application of the Boundary Element Method to Elastic Wave Scattering Problems in Ultrasonic Nondestructive Evaluation.

    NASA Astrophysics Data System (ADS)

    Schafbuch, Paul Jay

    The boundary element method (BEM) is used to numerically simulate the interaction of ultrasonic waves with material defects such as voids, inclusions, and open cracks. The time harmonic formulation is in 3D and therefore allows flaws of arbitrary shape to be modeled. The BEM makes such problems feasible because the underlying boundary integral equation only requires a surface (2D) integration and difficulties associated with the seemingly infinite extent of the host domain are not encountered. The computer code utilized in this work is built upon recent advances in elastodynamic boundary element theory such as a scheme for self adjusting integration order and singular integration regularization. Incident fields may be taken as compressional or shear plane waves or predicted by an approximate Gauss -Hermite beam model. The code is highly optimized for voids and has been coupled with computer aided engineering packages for automated flaw shape definition and mesh generation. Subsequent graphical display of intermediate results supports model refinement and physical interpretation. Final results are typically cast in a nondestructive evaluation (NDE) context as either scattering amplitudes or flaw signals (via a measurement model based on a reciprocity integral). The near field is also predicted which allows for improved physical insight into the scattering process and the evaluation of certain modeling approximations. The accuracy of the BEM approach is first examined by comparing its predictions to those of other models for single, isolated scatterers. The comparisons are with the predictions of analytical solutions for spherical defects and with MOOT and T-matrix calculations for axisymmetric flaws. Experimental comparisons are also made for volumetric shapes with different characteristic dimensions in all three directions, since no other numerical approach has yet produced results of this type. Theoretical findings regarding the fictitious eigenfrequency difficulty are substantiated through the analytical solution of a fundamental elastodynamics problem and corresponding BEM studies. Given the confidence in the BEM technique engendered by these comparisons, it is then used to investigate the modeling of "open", cracklike defects amenable to a volumetric formulation. The limits of applicability of approximate theories (e.g., quasistatic, Kirchhoff, and geometric theory of diffraction) are explored for elliptical cracks, from this basis. The problem of two interacting scatterers is then considered. Results from a fully implicit approach and from a more efficient hybrid scheme are compared with generalized Born and farfield approximate interaction theories.

  20. Application of the boundary element method to elastic wave scattering problems in ultrasonic nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Schafbuch, Paul Jay

    1991-02-01

    The boundary element method (BEM) is used to numerically simulate the interaction of ultrasonic waves with material defects such as voids, inclusions, and open cracks. The time harmonic formulation is in 3D and therefore allows flaws of arbitrary shape to be modeled. The BEM makes such problems feasible because the underlying boundary integral equation only requires a surface (2D) integration and difficulties associated with the seemingly infinite extent of the host domain are not encountered. The computer code utilized in this work is built upon recent advances in elastodynamic boundary element theory such as a scheme for self adjusting integration order and singular integration regularization. Incident fields may be taken as compressional or shear plane waves or predicted by an approximate Gauss-Hermite beam model. The code is highly optimized for voids and has been coupled with computer aided engineering packages for automated flaw shape definition and mesh generation. Subsequent graphical display of intermediate results supports model refinement and physical interpretation. Final results are typically cast in a nondestructive evaluation (NDE) context as either scattering amplitudes or flaw signals (via a measurement model based on a reciprocity integral). The near field is also predicted which allows for improved physical insight into the scattering process and the evaluation of certain modeling approximations. The accuracy of the BEM approach is first examined by comparing its predictions to those of other models for single, isolated scatters. The comparisons are with the predictions of analytical solutions for spherical defects and with MOOT and T-matrix calculations for axisymmetric flaws. Experimental comparisons are also made for volumetric shapes with different characteristic dimensions in all three directions, since no other numerical approach has yet produced results of this type. Theoretical findings regarding the fictitious eigenfrequency difficulty are substantiated through the analytical solution of a fundamental elastodynamics problem and corresponding BEM studies. Given the confidence in the BEM technique engendered by these comparisons, it is then used to investigate the modeling of 'open', cracklike defects amenable to a volumetric formulation. The limits of applicability of approximate theories (e.g., quasistatic, Kirchhoff, and geometric theory of diffraction) are explored for elliptical cracks, from this basis. The problem of two interacting scatterers is then considered. Results from a fully implicit approach and from a more efficient hybrid scheme are compared with generalized Born and farfield approximate interaction theories.

  1. An evaluation of leaf biomass : length ratio as a tool for nondestructive assessment in eelgrass (Zostera marina L.).

    PubMed

    Echavarria-Heras, Hector; Solana-Arellano, Elena; Lee, Kun-Seop; Hosokawa, Shinya; Franco-Vizcaíno, Ernesto

    2012-01-01

    The characterization of biomass and its dynamics provides valuable information for the assessment of natural and transplanted eelgrass populations. The need for simple, nondestructive assessments has led to the use of the leaf biomass-to-length ratio for converting leaf-length measurements, which can be easily obtained, to leaf growth rates through the plastochrone method. Using data on leaf biomass and length collected in three natural eelgrass populations and a mesocosm, we evaluated the suitability of a leaf weight-to-length ratio for nondestructive assessments. For the data sets considered, the isometric scaling that sustains the weight-to-length proxy always produced inconsistent fittings, and for leaf-lengths greater than a threshold value, the conversion of leaf length to biomass generated biased estimations. In contrast, an allometric scaling of leaf biomass and length was highly consistent in all the cases considered. And these nondestructive assessments generated reliable levels of reproducibility in leaf biomass for all the ranges of variability in leaf lengths. We argue that the use of allometric scaling for the representation of leaf biomass in terms of length provides a more reliable approach for estimating eelgrass biomass. PMID:22645432

  2. Evaluation of electrode shape and nondestructive evaluation method for welded solar cell interconnects

    NASA Technical Reports Server (NTRS)

    Baraona, C. R.; Klima, S. J.; Moore, T. J.; Frey, W. E.; Forestieri, A. F.

    1982-01-01

    Resistance welds of solar cell interconnect tabs were evaluated. Both copper-silver and silver-silver welds were made with various heat inputs and weld durations. Parallel gap and annular gap weld electrode designs were used. The welds were analyzed by light microscope, electron microprobe and scanning laser acoustic microscope. These analyses showed the size and shape of the weld, the relationship between the acoustic micrographs, the visible electrode footprint, and the effect of electrode misalignment. The effect of weld heat input on weld microstructure was also shown.

  3. The RAMANITA method for non-destructive and in situ semi-quantitative chemical analysis of mineral solid-solutions by multidimensional calibration of Raman wavenumber shifts.

    PubMed

    Smith, David C

    2005-08-01

    The "RAMANITA" method, for semi-quantitative chemical analysis of mineral solid-solutions by multidimensional calibration of Raman wavenumber shifts and mathematical calculation by simultaneous equations, is published here in detail in English for the first time. It was conceived by the present writer 20 years ago for binary and ternary pyroxene and garnet systems. The mathematical description was set out in 1989, but in an abstract in an obscure French special publication. Detailed "step-by-step" calibration of two garnet ternaries, followed by their linking, in the early 1990s provided a hexary garnet database. Much later, using this garnet database, which forms part of his personal database called RAMANITA, the present writer began to develop the method by improving the terminology, automating the calculations, discussing problems and experimenting with different real chemical problems in archaeometry. Although this RAMANITA method has been very briefly mentioned in two recent books, the necessary full mathematical explanation is given only here. The method will find application in any study which requires obtaining a non-destructive semi-quantitative chemical analysis from mineral solid solutions that cannot be analysed by any destructive analytical method, in particular for archaeological, geological or extraterrestrial research projects, e.g. Recently some other workers have begun deducing chemical compositions from Raman wavenumber shifts in multivariate chemical space, but the philosophical approach is quite different. PMID:16029851

  4. Theory and application of high temperature superconducting eddy current probes for nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Claycomb, James Ronald

    1998-10-01

    Several High-T c Superconducting (HTS) eddy current probes have been developed for applications in electromagnetic nondestructive evaluation (NDE) of conducting materials. The probes utilize high-T c SUperconducting Quantum Interference Device (SQUID) magnetometers to detect the fields produced by the perturbation of induced eddy currents resulting from subsurface flaws. Localized HTS shields are incorporated to selectively screen out environmental electromagnetic interference and enable movement of the instrument in the Earth's magnetic field. High permeability magnetic shields are employed to focus flux into, and thereby increase the eddy current density in the metallic test samples. NDE test results are presented, in which machined flaws in aluminum alloy are detected by probes of different design. A novel current injection technique performing NDE of wires using SQUIDs is also discussed. The HTS and high permeability shields are designed based on analytical and numerical finite element method (FEM) calculations presented here. Superconducting and high permeability magnetic shields are modeled in uniform noise fields and in the presence of dipole fields characteristic of flaw signals. Several shield designs are characterized in terms of (1) their ability to screen out uniform background noise fields; (2) the resultant improvement in signal-to-noise ratio and (3) the extent to which dipole source fields are distorted. An analysis of eddy current induction is then presented for low frequency SQUID NDE. Analytical expressions are developed for the induced eddy currents and resulting magnetic fields produced by excitation sources above conducting plates of varying thickness. The expressions derived here are used to model the SQUID's response to material thinning. An analytical defect model is also developed, taking into account the attenuation of the defect field through the conducting material, as well as the current flow around the edges of the flaw. Time harmonic FEM calculations are then used to model the electromagnetic response of eight probe designs, consisting of an eddy current drive coil coupled to a SQUID surrounded by superconducting and/or high permeability magnetic shielding. Simulations are carried out with the eddy current probes located a finite distance above a conducting surface. Results are quantified in terms of shielding and focus factors for each probe design.

  5. Optical Calibration Process Developed for Neural-Network-Based Optical Nondestructive Evaluation Method

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.

    2004-01-01

    A completely optical calibration process has been developed at Glenn for calibrating a neural-network-based nondestructive evaluation (NDE) method. The NDE method itself detects very small changes in the characteristic patterns or vibration mode shapes of vibrating structures as discussed in many references. The mode shapes or characteristic patterns are recorded using television or electronic holography and change when a structure experiences, for example, cracking, debonds, or variations in fastener properties. An artificial neural network can be trained to be very sensitive to changes in the mode shapes, but quantifying or calibrating that sensitivity in a consistent, meaningful, and deliverable manner has been challenging. The standard calibration approach has been difficult to implement, where the response to damage of the trained neural network is compared with the responses of vibration-measurement sensors. In particular, the vibration-measurement sensors are intrusive, insufficiently sensitive, and not numerous enough. In response to these difficulties, a completely optical alternative to the standard calibration approach was proposed and tested successfully. Specifically, the vibration mode to be monitored for structural damage was intentionally contaminated with known amounts of another mode, and the response of the trained neural network was measured as a function of the peak-to-peak amplitude of the contaminating mode. The neural network calibration technique essentially uses the vibration mode shapes of the undamaged structure as standards against which the changed mode shapes are compared. The published response of the network can be made nearly independent of the contaminating mode, if enough vibration modes are used to train the net. The sensitivity of the neural network can be adjusted for the environment in which the test is to be conducted. The response of a neural network trained with measured vibration patterns for use on a vibration isolation table in the presence of various sources of laboratory noise is shown. The output of the neural network is called the degradable classification index. The curve was generated by a simultaneous comparison of means, and it shows a peak-to-peak sensitivity of about 100 nm. The following graph uses model generated data from a compressor blade to show that much higher sensitivities are possible when the environment can be controlled better. The peak-to-peak sensitivity here is about 20 nm. The training procedure was modified for the second graph, and the data were subjected to an intensity-dependent transformation called folding. All the measurements for this approach to calibration were optical. The peak-to-peak amplitudes of the vibration modes were measured using heterodyne interferometry, and the modes themselves were recorded using television (electronic) holography.

  6. Nondestructive evaluation of the semiconductor interface states' density using the transverse acoustoelectric voltage

    NASA Astrophysics Data System (ADS)

    Davari, B.; Azar, M. Tabib; Liu, T.; Das, P.

    1986-01-01

    Nondestructive determination of the interface states' density ( Dit) is presented. The measurement technique, utilizing the surface acoustic waves, is applied to silicon/thermal oxide structure. The detected signal is the transverse acoustoelectric voltage amplitude (TAV) which is monitored as a function of the applied bias voltage (TAV- V). Dit is measured by comparing the theoretical and experimental TAV- V curves. The calculation procedure of the Dit and the experimental example are presented.

  7. Nondestructive Evaluation of Rubber Compounds by Terahertz Time-Domain Spectroscopy

    NASA Astrophysics Data System (ADS)

    Hirakawa, Yasuyuki; Ohno, Yoshitomo; Gondoh, Toyohiko; Mori, Tetsuo; Takeya, Kei; Tonouchi, Masayoshi; Ohtake, Hideyuki; Hirosumi, Tomoya

    2011-12-01

    Rubber compounds were investigated by terahertz time-domain spectroscopy. Terahertz absorption spectra of crude rubbers and additives were measured as well as those of acrylonitrile-butadiene rubber compounds, which included the additives. It was found that carbon black, which is one of the additives and serves as a filler, dominates the terahertz absorption owing to its metallic characteristics. Thus, terahertz spectroscopy is a useful method for rapid nondestructive inspection during the rubber production.

  8. Nondestructive Evaluation on Hydrided LWR Fuel Cladding by Small Angle Incoherent Neutron Scattering of Hydrogen

    SciTech Connect

    Yan, Yong; Qian, Shuo; Littrell, Ken; Parish, Chad M; Bell, Gary L; Plummer, Lee K

    2013-01-01

    A non-destructive neutron scattering method was developed to precisely measure the uptake of total hydrogen in nuclear grade Ziraloy-4 cladding. The hydriding apparatus consists of a closed stainless steel vessel that contains Zr alloy specimens and H gas. By controlling the initial H gas pressure in the vessel and the temperature profile, target H concentrations from tens of ppm to a few thousands of wppm have been successfully achieved. Following H charging, the H content of the hydrided specimens was measured using the vacuum hot extraction method (VHE), by which the samples with desired H concentration were selected for the neutron study. Small angle neutron incoherent scattering (SANIS) were performed in the High Flux Isotope Reactor at Oak Ridge national Laboratory (ORNL). Our study indicates that a very small amount ( 20 ppm) H in commercial Zr cladding can be measured very accurately in minutes for a wide range of H concentration by a nondestructive method. The H distribution in a tube sample was obtained by scaling the neutron scattering rate with a factor, which is determined by calibration process with direct chemical analysis method on the specimen. This scale factor can be used for future test with unknown H concentration, thus provide a nondestructive method for absolute H concentration determination.

  9. Nondestructive Characterization of Adhesive Bonds from Guided Wave Data

    NASA Technical Reports Server (NTRS)

    Mal, A.; Lih, S-S.; Bar-Cohen, Y.

    1994-01-01

    The critical role played by interface zones in the fracture and failure of composites and other bonded materials is well known. The existing nondestructive evaluation methods are generally not capable of yielding useful quantitative information of the strength of an interface.

  10. Three-dimensional non-destructive optical evaluation of laser-processing performance using optical coherence tomography

    PubMed Central

    Kim, Youngseop; Choi, Eun Seo; Kwak, Wooseop; Shin, Yongjin; Jung, Woonggyu; Ahn, Yeh-Chan; Chen, Zhongping

    2014-01-01

    We demonstrate the use of optical coherence tomography (OCT) as a non-destructive diagnostic tool for evaluating laser-processing performance by imaging the features of a pit and a rim. A pit formed on a material at different laser-processing conditions is imaged using both a conventional scanning electron microscope (SEM) and OCT. Then using corresponding images, the geometrical characteristics of the pit are analyzed and compared. From the results, we could verify the feasibility and the potential of the application of OCT to the monitoring of the laser-processing performance. PMID:24932051

  11. Development of Standards for Nondestructive Evaluation of COPVs Used in Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Waller, Jess M.; Saulsberry, Regor L.

    2012-01-01

    Composite OverWrapped Pressure Vessels (COPVs) are currently accepted by NASA based on design and qualification requirements and generally not verified by NDE for the following reasons: (1) Manufactures and end users generally do not have experience and validated quantitative methods of detecting flaws and defects of concern (1-a) If detected, the flaws are not adequately quantified and it is unclear how they may contribute to degradation in mechanical response (1-b) Carbon-epoxy COPVs also extremely sensitive to impact damage and impacts may be below the visible detection threshold (2) If damage is detected, this generally results in rejection since the effect on mechanical response is generally not known (3) NDE response has not generally been fully characterized, probability of detection (POD) established, and processes validated for evaluation of vessel condition as manufactured and delivered.

  12. Nondestructive evaluation of progressive neuronal changes in organotypic rat hippocampal slice cultures using ultrahigh-resolution optical coherence microscopy

    PubMed Central

    Li, Fengqiang; Song, Yu; Dryer, Alexandra; Cogguillo, William; Berdichevsky, Yevgeny; Zhou, Chao

    2014-01-01

    Abstract. Three-dimensional tissue cultures have been used as effective models for studying different diseases, including epilepsy. High-throughput, nondestructive techniques are essential for rapid assessment of disease-related processes, such as progressive cell death. An ultrahigh-resolution optical coherence microscopy (UHR-OCM) system with ∼1.5  μm axial resolution and ∼2.3  μm transverse resolution was developed to evaluate seizure-induced neuronal injury in organotypic rat hippocampal cultures. The capability of UHR-OCM to visualize cells in neural tissue was confirmed by comparison of UHR-OCM images with confocal immunostained images of the same cultures. In order to evaluate the progression of neuronal injury, UHR-OCM images were obtained from cultures on 7, 14, 21, and 28 days in vitro (DIVs). In comparison to DIV 7, statistically significant reductions in three-dimensional cell count and culture thickness from UHR-OCM images were observed on subsequent time points. In cultures treated with kynurenic acid, significantly less reduction in cell count and culture thickness was observed compared to the control specimens. These results demonstrate the capability of UHR-OCM to perform rapid, label-free, and nondestructive evaluation of neuronal death in organotypic hippocampal cultures. UHR-OCM, in combination with three-dimensional tissue cultures, can potentially prove to be a promising tool for high-throughput screening of drugs targeting various disorders. PMID:25750928

  13. A Nondestructive Evaluation Method: Measuring the Fixed Strength of Spot-Welded Joint Points by Surface Electrical Resistivity.

    PubMed

    Shimamoto, Akira; Yamashita, Keitaro; Inoue, Hirofumi; Yang, Sung-Mo; Iwata, Masahiro; Ike, Natsuko

    2013-04-01

    Destructive tests are generally applied to evaluate the fixed strength of spot-welding nuggets of zinc-plated steel (which is a widely used primary structural material for automobiles). These destructive tests, however, are expensive and time-consuming. This paper proposes a nondestructive method for evaluating the fixed strength of the welded joints using surface electrical resistance. A direct current nugget-tester and probes have been developed by the authors for this purpose. The proposed nondestructive method uses the relative decrease in surface electrical resistance, α. The proposed method also considers the effect of the corona bond. The nugget diameter is estimated by two factors: R Quota, which is calculated from variation of resistance, and a constant that represents the area of the corona bond. Since the maximum tensile strength is correlated with the nugget diameter, it can be inferred from the estimated nugget diameter. When appropriate measuring conditions for the surface electrical resistance are chosen, the proposed method can effectively evaluate the fixed strength of the spot-welded joints even if the steel sheet is zinc-plated. PMID:24891747

  14. Pod Generator Project, Development of Numerical Modeling Tools for Quantitative Assessment of the Performance of Non-Destructive Inspection Techniques

    NASA Astrophysics Data System (ADS)

    Bloom, J. G. P.; Stelwagen, U.; Mast, A.; Volker, A. W. F.; Krom, A. H. M.; Mohamoud, A. A.; Van Gils, G. P.

    2009-03-01

    Risk based inspection strategies rely on detailed knowledge of the performance of inspection techniques. It is well known that every inspection technique has limitations in terms of reliability and effectiveness. Moreover, these are influenced by many factors. E.g. it depends on operator skills, inspection procedure, defect and object geometry as well as technique specific instrument properties and settings. The objective of the "POD generator" project is to develop a numerical modeling approach to assess inspection effectiveness for a specific technique and situation flexibly and reliably yet at acceptable costs. Besides the models to simulate various degradation mechanisms, numerical models have been developed and validated for accurately simulating the physics of inspection techniques. Also the human factor is taken into account. These numerical models are then used to generate quantitative probability of detection (POD) curves. This will be illustrated for ultrasonic time-of-flight-diffraction (TOFD) inspection of fatigue cracks.

  15. Nondestructive Evaluation of Foam Insulation on the Space Shuttle External Tank

    NASA Technical Reports Server (NTRS)

    Richter, Joel; Walker, James L.

    2006-01-01

    Foam loss on the External Tank (ET) during launch can be caused by a number of factors. Voids are the best understood mechanism of foam loss, although it is known that delaminations, cracks and crushed foam can also lead to liberation of foam. Shortly after the Columbia accident, work began on non-destructive evaluation of foam targeted at finding voids and delaminations. After several months of searching for candidate methods capable of inspecting ET foam, the five most promising techniques were taken through a blind test and narrowed down to two methods to develop and use for inspection of the ET. These methods were backscatter radiography and terahertz imaging. The backscatter radiography system measures a test part by detecting Compton backscattered x-ray energy generated by a collimated beam of x-rays directed at the test subject. This collimated beam is scanned across the subject, recording scatter intensity data one pixel at a time until the area of interest is covered. The resulting data can be used to generate an image similar to a radiograph. Some depth information can be gathered utilizing apertures or collimation on the detectors. The detectors are located around the collimated source, making this a single sided inspection. The void detection limit with the currently utilized system is around 0.5 inches in diameter by 0.2 inches high. The terahertz imaging system inspects a test part by utilizing a transceiver to emit a pulse focused at the aluminum skin of the ET, which reflects it back to the transceiver where it is analyzed. The transceiver is scanned across the area of interest until a measurement has been taken at every location. Amplitude, time delay and frequency content are examined to note any discontinuities which may be the result of a void or other type of defect. The pulse currently utilized is in the millimeter wave regime. The void detection limit with this system is around 0.5 inches in diameter by 0.2 inches high. With increased interest in other causes of foam loss following the flight of Discovery in July 2005, laser shearography was added to the techniques used for inspecting ET foam. The shearography method records a sheared image of a laser speckle pattern projected on a test part before And after some sort of excitation. The resultant fringe pattern allows the slope of the out of plane displacement to be measured. For crushed and delaminated foam applications, a non-contact air coupled acoustic force is used to excite the surface of the foam. Regions without defects tend to respond differently to the sound energy than do regions with defects, generating a map of the foam integrity. Foam crushed to a depth of about 0.1 inches is detectable with shearography even after it has relaxed to its original shape.

  16. Development and optimization of thermographic techniques for Non-Destructive Evaluation of multilayered structures

    NASA Astrophysics Data System (ADS)

    Gavrilov, Dmitry J.

    Quality control of modern materials is of the utmost importance in science and industry. Methods for nondestructive evaluation of material properties and the presence of defects are numerous. They differ in terms of their sensitivity and applicability in various conditions, and they provide different kinds of data such as the speed of sound in the material, its hardness, radiation absorption, etc. Based on measured characteristics an analyst makes a decision on the material studied. This work addresses a class of methods known as active thermographic analysis. Thermography analyzes the temperature of the surface of the sample under different external conditions. By keeping track of temperature changes at the surface caused by a deposition of heat on the sample one can determine its material properties such as theand processing the data captured it is possible to make decisions on parameters of this sample. Among the data which can be acquired are such important information as the location of internal defects (e.g., detachments, hollows, inclusions), thickness of the material layers, thermal parameters of the material and the location of internal defects (e.g., detachments, hollows, inclusions). The first part of this research investigates a method for analysis of layered composite materials using the approach based on interference of so called temperature waves. As demonstrated using the expressions derived, one can determine the thermal properties of the layers of the sample by applying a harmonically modulated heat flux to the surfaces and measuring the phase of the periodically changing surface temperature. This approach can be of use in the field of designing and analysis of composite thermal insulation coatings. In the second part of this work a method of analyzing objects of fine art was investigated, particularly - detection of subsurface defects. In the process of preserving art it is of primary importance to determine whether restoration is necessary. Moreover, this analysis should be done on a regular basis to prevent defects from increasing in size over time. Conventional methods, such as infrared photography and X-ray radiography may not be suitable for this application, because most of detachments are too deep for infrared to reach them, and too thin for providing enough contrast on X-ray images. This highlights the need for the development of methodsfor detection of hidden defects and structure of art pieces to detect the structure of art pieces and any hidden defects present. Thermography has strong potential as a tool for non-invasive analysis of works of art and only recently has it been actively promoted into this field. However, due to the general unpredictability of the structure of brushstrokes as well as the properties of paint, it is difficult to apply a physical model to the analysis of paintings. In addition, an improved method is proposed. This proposed method is mainly based on PCT, but it is capable of returning clear images of subsurface defects and the structure of the support. Unlike standard PCT images, the images acquired by this method do not exhibit visually similar features.

  17. Non-destructive high-resolution thermal imaging techniques to evaluate wildlife and delicate biological samples

    NASA Astrophysics Data System (ADS)

    Lavers, C.; Franklin, P.; Franklin, P.; Plowman, A.; Sayers, G.; Bol, J.; Shepard, D.; Fields, D.

    2009-07-01

    Thermal imaging cameras now allows routine monitoring of dangerous yet endangered wildlife in captivity. This study looks at the potential applications of radiometrically calibrated thermal data to wildlife, as well as providing parameters for future materials applications. We present a non-destructive active testing technique suitable for enhancing imagery contrast of thin or delicate biological specimens yielding improved thermal contrast at room temperature, for analysis of sample thermal properties. A broad spectrum of animals is studied with different textured surfaces, reflective and emissive properties in the infra red part of the electromagnetic spectrum. Some surface features offer biomimetic materials design opportunities.

  18. Nondestructive Evaluation (NDE) Results on Sikorsky Aircraft Survivable Affordable Reparable Airframe Program (SARAP) Samples

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Anastasi, Robert F.; Madaras, Eric I.

    2004-01-01

    The Survivable, Affordable, Reparable Airframe Program (SARAP) will develop/produce new structural design concepts with lower structural weight, reduced manufacturing complexity and development time, increased readiness, and improved threat protection. These new structural concepts will require advanced field capable inspection technologies to help meet the SARAP structural objectives. In the area of repair, damage assessment using nondestructive inspection (NDI) is critical to identify repair location and size. The purpose of this work is to conduct an assessment of new and emerging NDI methods that can potentially satisfy the SARAP program goals.

  19. Application of Advanced Nondestructive Evaluation Techniques for Cylindrical Composite Test Samples

    NASA Technical Reports Server (NTRS)

    Martin, Richard E.; Roth, Donald J.; Salem, Jonathan A.

    2013-01-01

    Two nondestructive methods were applied to composite cylinder samples pressurized to failure in order to determine manufacturing quality and monitor damage progression under load. A unique computed tomography (CT) image processing methodology developed at NASA Glenn Research was used to assess the condition of the as-received samples while acoustic emission (AE) monitoring was used to identify both the extent and location of damage within the samples up to failure. Results show the effectiveness of both of these methods in identifying potentially critical fabrication issues and their resulting impact on performance.

  20. Traceable Quantitative Raman Microscopy and X-ray Fluorescence Analysis as Nondestructive Methods for the Characterization of Cu(In,Ga)Se2 Absorber Films.

    PubMed

    Zakel, Sabine; Pollakowski, Beatrix; Streeck, Cornelia; Wundrack, Stefan; Weber, Alfons; Brunken, Stefan; Mainz, Roland; Beckhoff, Burckhardt; Stosch, Rainer

    2016-02-01

    The traceability of measured quantities is an essential condition when linking process control parameters to guaranteed physical properties of a product. Using Raman spectroscopy as an analytical tool for monitoring the production of Cu(In1-xGax)Se2 thin-film solar cells, proper calibration with regard to chemical composition and lateral dimensions is a key prerequisite. This study shows how the multiple requirements of calibration in Raman microscopy might be addressed. The surface elemental composition as well as the integral elemental composition of the samples is traced back by reference-free X-ray fluorescence analysis. Reference Raman spectra are then generated for the relevant Cu(In1-xGax)Se2 related compounds. The lateral dimensions are calibrated with the help of a novel dimensional standard whose regular structures have been traced back to the International System of Units by metrological scanning force microscopy. On this basis, an approach for the quantitative determination of surface coverage values from lateral Raman mappings is developed together with a complete uncertainty budget. Raman and X-ray spectrometry have here been proven as complementary nondestructive methods combining surface sensitivity and in-depth information on elemental and species distribution for the reliable quality control of Cu(In1-xGax)Se2 absorbers and Cu(In1-xGax)3Se5 surface layer formation. PMID:26903563

  1. Quantitative non-destructive evaluation of porous composite materials based on ultrasonic wave propagation

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1987-01-01

    Porosity in composite media using ultrasonic waves is characterized. The derivation of local approximations to the Kramers-Kronig relations are presented and it is shown that they may also be applicable to systems that could conceivably exhibit considerable dispersion such as composite laminates containing porosity.

  2. Pulse thermography for quantitative nondestructive evaluation of sound, de-mineralized and re-mineralized enamel

    NASA Astrophysics Data System (ADS)

    Ando, Masatoshi; Sharp, Nathan; Adams, Douglas

    2012-04-01

    Current limitations for diagnosing mineralization state of tooth enamel can lead to improper surgical treatments. A method is investigated by which the tooth health state is characterized according to its thermal response, which is hypothesized to be sensitive to increased porosity in enamel that is caused by demineralization. Several specimens consisting of previously extracted human teeth a re prepared by exposure to Streptococcus mutans A32-2 in trypticase-soy-borth supplemented with 5% sucrose at 37°C for 3 or 6 days to de-mineralize two 1×1mm2-windows on each tooth. One of these windows is then re-mineralized with 250 or 1,100ppm-F as NaF for 10 days by pH-cyclic-model. Pulse thermography is used to measure the thermal response of these sections as well as the sound (healthy) portions of the specimen. A spatial profile of the thermal parameters of the specimens is then extracted from the thermography data and are used to compare the sound, de-mineralized, and re-mineralized areas. Results show that the thermal parameters are sensitive to the mineralization state of the tooth and that this method has the potential to accurately and quickly characterize the mineralization state of teeth, thereby allowing future dentists to make informed decisions regarding the best treatment for teeth that have experienced demineralization.

  3. Noncontact, nondestructive elasticity evaluation of sound and demineralized human dental enamel using a laser ultrasonic surface wave dispersion technique

    NASA Astrophysics Data System (ADS)

    Wang, Hsiao-Chuan; Fleming, Simon; Lee, Yung-Chun; Law, Susan; Swain, Michael; Xue, Jing

    2009-09-01

    Laser ultrasonic nondestructive evaluation (NDE) methods have been proposed to replace conventional in vivo dental clinical diagnosis tools that are either destructive or incapable of quantifying the elasticity of human dental enamel. In this work, a laser NDE system that can perform remote measurements on samples of small dimensions is presented. A focused laser line source is used to generate broadband surface acoustic wave impulses that are detected with a simplified optical fiber interferometer. The measured surface wave velocity dispersion spectrum is in turn used to characterize the elasticity of the specimen. The NDE system and the analysis technique are validated with measurements of different metal structures and then applied to evaluate human dental enamel. Artificial lesions are prepared on the samples to simulate different states of enamel elasticity. Measurement results for both sound and lesioned regions, as well as lesions of different severity, are clearly distinguishable from each other and fit well with physical expectations and theoretical value. This is the first time, to the best of our knowledge, that a laser-based surface wave velocity dispersion technique is successfully applied on human dental enamel, demonstrating the potential for noncontact, nondestructive in vivo detection of the development of carious lesions.

  4. A study of active thermography approaches for the non-destructive testing and evaluation of aerospace structures

    NASA Astrophysics Data System (ADS)

    Avdelidis, Nicolas P.; Ibarra-Castanedo, Clemente; Marioli-Riga, Zaira P.; Bendada, Abdelhakim; Maldague, Xavier P. V.

    2008-03-01

    The prerequisite for more competent and cost effective aircraft has led to the evolution of innovative testing and evaluation procedures. Non-destructive testing and evaluation (NDT & E) techniques for assessing the integrity of an aircraft structure are essential to both reduce manufacturing costs and out of service time of aircraft due to maintenance. Nowadays, active - transient thermal NDT & E (i.e. thermography) is commonly used for assessing aircraft composites. This research work evaluates the potential of pulsed thermography (PT) and/or pulsed phase thermography (PPT) for assessing defects (i.e. impact damage and inclusions for delaminations) on GLARE and GLARE type composites. Finally, in the case of the detection of inserts - delaminations C-Scan ultrasonic testing was also used with the intention of providing supplementary results.

  5. The RAMANITA © method for non-destructive and in situ semi-quantitative chemical analysis of mineral solid-solutions by multidimensional calibration of Raman wavenumber shifts

    NASA Astrophysics Data System (ADS)

    Smith, David C.

    2005-08-01

    The "RAMANITA ©" method, for semi-quantitative chemical analysis of mineral solid-solutions by multidimensional calibration of Raman wavenumber shifts and mathematical calculation by simultaneous equations, is published here in detail in English for the first time. It was conceived by the present writer 20 years ago for binary and ternary pyroxene and garnet systems. The mathematical description was set out in 1989, but in an abstract in an obscure French special publication. Detailed "step-by-step" calibration of two garnet ternaries, followed by their linking, by M. Pinet and D.C. Smith in the early 1990s provided a hexary garnet database. Much later, using this garnet database, which forms part of his personal database called RAMANITA ©, the present writer began to develop the method by improving the terminology, automating the calculations, discussing problems and experimenting with different real chemical problems in archaeometry. Although this RAMANITA © method has been very briefly mentioned in two recent books, the necessary full mathematical explanation is given only here. The method will find application in any study which requires obtaining a non-destructive semi-quantitative chemical analysis from mineral solid solutions that cannot be analysed by any destructive analytical method, in particular for archaeological, geological or extraterrestrial research projects, e.g. from gemstones or other crystalline artworks of the cultural heritage (especially by Mobile Raman Microscopy (MRM)) in situ in museums or at archaeological sites, including under water for subaquatic archaeometry; from scientifically precious mineral microinclusions (such as garnet or pyroxene within diamond); from minerals in rocks analysed in situ on planetary bodies by a rover (especially "at distance" by telescopy). Recently some other workers have begun deducing chemical compositions from Raman wavenumber shifts in multivariate chemical space, but the philosophical approach is quite different.

  6. Residual Detergent Detection Method for Nondestructive Cytocompatibility Evaluation of Decellularized Whole Lung Scaffolds.

    PubMed

    Zvarova, Barbora; Uhl, Franziska E; Uriarte, Juan J; Borg, Zachary D; Coffey, Amy L; Bonenfant, Nicholas R; Weiss, Daniel J; Wagner, Darcy E

    2016-05-01

    The development of reliable tissue engineering methods using decellularized cadaveric or donor lungs could potentially provide a new source of lung tissue. The vast majority of current lung decellularization protocols are detergent based and incompletely removed residual detergents may have a deleterious impact on subsequent scaffold recellularization. Detergent removal and quality control measures that rigorously and reliably confirm removal, ideally utilizing nondestructive methods, are thus critical for generating optimal acellular scaffolds suitable for potential clinical translation. Using a modified and optimized version of a methylene blue-based detergent assay, we developed a straightforward, noninvasive method for easily and reliably detecting two of the most commonly utilized anionic detergents, sodium deoxycholate (SDC) and sodium dodecyl sulfate (SDS), in lung decellularization effluents. In parallel studies, we sought to determine the threshold of detergent concentration that was cytotoxic using four different representative human cell types utilized in the study of lung recellularization: human bronchial epithelial cells, human pulmonary vascular endothelial cells (CBF12), human lung fibroblasts, and human mesenchymal stem cells. Notably, different cells have varying thresholds for either SDC or SDS-based detergent-induced cytotoxicity. These studies demonstrate the importance of reliably removing residual detergents and argue that multiple cell lines should be tested in cytocompatibility-based assessments of acellular scaffolds. The detergent detection assay presented here is a useful nondestructive tool for assessing detergent removal in potential decellularization schemes or for use as a potential endpoint in future clinical schemes, generating acellular lungs using anionic detergent-based decellularization protocols. PMID:26905643

  7. Nondestructive evaluation of the oxidation and strength of the Fort Saint Vrain HTGR support block

    SciTech Connect

    Tingey, G.L.; Posakony, G.J.; Morgan, W.C.; Prince, J.M.; Hill, R.W.; Lessor, D.L.

    1982-04-01

    Non-destructive detection of changes in the strength of graphite support structures in a HTGR appears to be feasible using sonic velocity measurements where access for through transmission is possible. Therefore, future HTGR designs should consider providing such access. Where access is not available, strength changes can be correlated with oxidation profiles in the support member. These oxidation profiles can be determined non-destructively by a combination of eddy current measurements to detect near surface oxidation and sonic backscattering measurements designed to determine oxidation in depth. The Fort Saint Vrain reactor provides an operating reactor to test the applicability of the eddy current and sonic backscattering techniques for determination of oxidation in a support block. Furthermore, such tests in Fort Saint Vrain will supply base line data which will be useful in assuring an adequate strength of the support structure for the lifetime of the reactor. Equipment is, therefore, being developed for tests to be conducted during the next major refueling of the reactor.

  8. Qualitative and Quantitative Evaluation of Liver Diseases

    PubMed Central

    Milanese, M.; Molino, G.; Belforte, G.; Cravetto, C.; Frediani, S.; Bonn, B.; Saitta, L.

    1980-01-01

    A large number of biochemical tests and procedures is used for the evaluation of the many different functional activities (cholestasis, biosynthesis etc.) of the liver, but their usefulness for an effective improvement in the diagnostic assessment is questionable. This paper deals with the problem of evaluating and comparing the information content of single tests or groups of tests with respect to their ability in evaluating liver functions. The studied subjects (245) have been submitted to the usual clinical and laboratory investigations for hepatobiliary diseases. A degree of impairment (null, very light, medium, relevant) for each considered functional activity has been evaluated by six groups of experienced physicians. Two different approaches have been used for the selection of the most informative tests. The first one makes use of classical statistical allocation and feature selection methods. The second approach consists in deriving, from the measured values, an index of impairment, continuously varying from zero (null) to three (relevant). Two methods have been used: the first one based on possibility theory and fuzzy sets, the second one on principal components techniques in modeling non linear models. The ordering of the tests is made evaluating (by means of the cross-validation method) the prediction errors of the computed impairment degree. The second approach seems more suitable for the evaluation of functional activities and this is confirmed by the numerical results. However all the methods are in good agreement in ordering the groups of tests. The obtained results appear quite relevant from a clinical point of view: for example about twenty tests can give indication of each of the considered functional activity, but the use of more than four or five suitably selected tests gives no effective improvement in their assessment.

  9. Quantitative computed tomography evaluation of pulmonary disease.

    PubMed

    McEvoy, Fintan J; Buelund, Lene; Strathe, Anders B; Willesen, Jakob L; Koch, Jørgen; Webster, Pia; Hørlyck, Lasse; Svalastoga, Eiliv

    2009-01-01

    Objective assessment of pulmonary disease from computed tomography (CT) examinations is desirable but difficult. When such assessments can be made, it is important that they are related to some part of the pathophysiologic process present. Herein we propose that automated volume histogram analysis can yield data that allow differentiation of normal from abnormal lung, and that the magnitude of disease will have an association with objective CT indices. Data from pulmonary CT images from 34 foxes (six uninfected controls and 28 infected with Angiostrongylus vasorum, subdivided by age and infective dose) were available. Lung tissue was segmented from surrounding tissue using an automated segmentation method. A volume histogram showing voxel frequency for each CT number in the range -1024 to -250 HU was created from the entire image stack from each fox. Using these data, the inter-quartile range and the CT number at the 95th percentile were determined. The results showed that segmentation could be readily achieved but that areas of severely diseased lung were excluded. Based on two-way analysis of variance for both the inter-quartile range and the CT number at the 95th percentile, both quantities were significantly affected by the infection status of the animal and were related to worm burden (P < 0.001). The study shows that this form of analysis is readily achieved and provides quantitative data that can be used to assess disease severity, progression, and response to treatment. PMID:19241753

  10. Development of Non-destructive Evaluation System Using an HTS-SQUID Gradiometer with an External Pickup Coil

    NASA Astrophysics Data System (ADS)

    Kawano, J.; Kawauchi, S.; Ishikawa, F.; Tanabe, K.

    We are developing a new eddy-current non-destructive evaluation (NDE) system using a high-temperature superconducting quantum interference device (HTS-SQUID) gradiometer with the aim of applying it to power plants. Electric power facilities such as ducts and vessels are generally untransportable because of their size, and thus it is difficult to apply a conventional SQUID NDE system. The new NDE system employs an external Cu pickup coil which is supposed to be driven flexibly by a robot arm at room temperature and an HTS-SQUID chip which is placed in a magnetically shielded vessel. In the present research, we investigated the performance of an HTS-SQUID sensor connected with external pickup coils before mounting them to a robot arm. By varying the Cu coil conditions such as their sizes, the number of turns, and the diameter of wire, we qualitatively evaluated the frequency dependence of the effective area and the cutoff frequency.

  11. New measurement technique that uses three near infrared diode lasers for nondestructive evaluation of sugar content in fruits

    NASA Astrophysics Data System (ADS)

    Shimomura, Yoshiaki; Takami, Toshitaka; Ichimaru, Yoshiki; Matsuo, Kenichi; Hyodo, Ryuji

    2005-03-01

    For non-destructive evaluation of sugar content in fruits, it has been proposed new measurement technique that uses three near infrared diode lasers. The reflectance Ri at the wavelength λi is defined by the ratio of two diffuse light powers reaching the two receiving fibers that were positioned at the different distance from a light emitting fiber. The value γ = ln (Ri/Rk)/ln (Rj/Rk) reaches the value that doesn't approximately depend on optical path length. As a simulation result of γ to a modeled apple, it was found that there are some combinations of three near-infrared wavelengths in which the correlation of γ and the sugar content of fruits raise. We actually evaluated the sugar content of apples by the use of three diode lasers 911nm, 936nm and 1055nm. As a result, it was confirmed that the measurement technique proposed here was usefulness.

  12. Preliminary technique assessment for nondestructive evaluation certification of the NNWSI [Nevada Nuclear Waste Storage Investigations] disposal container closure

    SciTech Connect

    Day, R.A.

    1988-12-31

    Under the direction of the Department of Energy`s (DOE) Office of Civilian Radioactive Waste Management (OCRWM) program, the Nevada Nuclear Waste Storage Investigations (NNWSI) project is evaluating a candidate repository site at Yucca Mountain, Nevada, for permanent disposal of high-level nuclear waste. The Lawrence Livermore National Laboratory (LLNL), a participant in the NNWSI project, is developing waste package designs to meet the NRC requirements. One aspect of this waste package is the nondestructive testing of the final closure of the waste container. The container closure weld can best be nondestructively examined (NDE) by a combination of ultrasonics and liquid penetrants. This combination can be applied remotely and can meet stringent quality control requirements common to nuclear applications. Further development in remote systems and inspection will be required to meet anticipated requirements for flaw detection reliability and sensitivity. New research is not required but might reduce cost or inspection time. Ultrasonic and liquid penetrant methods can examine all closure methods currently being considered, which include fusion welding and inertial welding, among others. These NDE methods also have a history of application in high radiation environments and a well developed technology base for remote operation that can be used to reduce development and design costs. 43 refs., 23 figs., 3 tabs.

  13. Evaluation of non-destructive methods for estimating biomass in marshes of the upper Texas, USA coast

    USGS Publications Warehouse

    Whitbeck, M.; Grace, J.B.

    2006-01-01

    The estimation of aboveground biomass is important in the management of natural resources. Direct measurements by clipping, drying, and weighing of herbaceous vegetation are time-consuming and costly. Therefore, non-destructive methods for efficiently and accurately estimating biomass are of interest. We compared two non-destructive methods, visual obstruction and light penetration, for estimating aboveground biomass in marshes of the upper Texas, USA coast. Visual obstruction was estimated using the Robel pole method, which primarily measures the density and height of the canopy. Light penetration through the canopy was measured using a Decagon light wand, with readings taken above the vegetation and at the ground surface. Clip plots were also taken to provide direct estimates of total aboveground biomass. Regression relationships between estimated and clipped biomass were significant using both methods. However, the light penetration method was much more strongly correlated with clipped biomass under these conditions (R2 value 0.65 compared to 0.35 for the visual obstruction approach). The primary difference between the two methods in this situation was the ability of the light-penetration method to account for variations in plant litter. These results indicate that light-penetration measurements may be better for estimating biomass in marshes when plant litter is an important component. We advise that, in all cases, investigators should calibrate their methods against clip plots to evaluate applicability to their situation. ?? 2006, The Society of Wetland Scientists.

  14. Nondestructive evaluation of damage in SiC/Al metal matrix composite using x ray tomographic microscopy

    SciTech Connect

    Breunig, T.M.

    1992-01-01

    A fundamental understanding of damage evolution will be required before metal matrix composites (MMC) can be utilized safely for structural applications. Although macroscopic mechanical response to cyclic loading has been monitored in many mechanical and thermal test programs, little is known about the nucleation and growth of damage in MMC's. The goal of the present work is to improve the understanding of damage accumulation in SiC/Al using a new microscopic non-destructive volume-imaging technique, X-ray Tomographic Microscopy (XTM), which has resolution comparable to optical microscopy. Correlation of damage initiation and accumulation mechanisms and the macroscopic mechanical response of samples are discussed for continuous fiber SiC/Al MMC's. A series of mechanical tests were performed on a continuous, aligned fiber SiC/Al MMC, and the ensuing three-dimensional damage state was nondestructively characterized using XTM to map the x-ray absorptivity within the sample. The types of damage detected include: fiber fracture (SiC sheath, and C core), fiber-matrix interface microcracking, intra-ply matrix voids, and cracks. Quantitative three-dimensional measurements of damage are reported in as-fabricated, monotonically loaded and mechanically fatigue loaded SiC/Al. The XTM results indicate that increases in observed macroscopic structural stiffness during monotonic loading and the first few fatigue cycles of an MMC coupon correspond to elimination of processing-related matrix porosity and to displacement of the fibers from a somewhat irregular arrangement into a more nearly hexagonal array. The XTM of monotonically loaded samples also show that the carbon cores begin to fracture at or below 828 MPa, that is, at loads far less than those for fracture of the entire fiber. The fracture of the SiC sheath appears to be significantly affected by the fracture of the C cores.

  15. A quantitative method to evaluate neutralizer toxicity against Acanthamoeba castellanii.

    PubMed Central

    Buck, S L; Rosenthal, R A

    1996-01-01

    A standard methodology for quantitatively evaluating neutralizer toxicity against Acanthamoeba castellanii does not exist. The objective of this study was to provide a quantitative method for evaluating neutralizer toxicity against A. castellanii. Two methods were evaluated. A quantitative microtiter method for enumerating A. castellanii was evaluated by a 50% lethal dose endpoint method. The microtiter method was compared with the hemacytometer count method. A method for determining the toxicity of neutralizers for antimicrobial agents to A. castellanii was also evaluated. The toxicity to A. castellanii of Dey-Engley neutralizing broth was compared with Page's saline. The microtiter viable cell counts were lower than predicted by the hemacytometer counts. However, the microtiter method gives more reliable counts of viable cells. Dey-Engley neutralizing medium was not toxic to A. castellanii. The method presented gives consistent, reliable results and is simple compared with previous methods. PMID:8795247

  16. Electromagnetic Nondestructive Evaluation of Wire Insulation and Models of Insulation Material Properties

    NASA Technical Reports Server (NTRS)

    Bowler, Nicola; Kessler, Michael R.; Li, Li; Hondred, Peter R.; Chen, Tianming

    2012-01-01

    Polymers have been widely used as wiring electrical insulation materials in space/air-craft. The dielectric properties of insulation polymers can change over time, however, due to various aging processes such as exposure to heat, humidity and mechanical stress. Therefore, the study of polymers used in electrical insulation of wiring is important to the aerospace industry due to potential loss of life and aircraft in the event of an electrical fire caused by breakdown of wiring insulation. Part of this research is focused on studying the mechanisms of various environmental aging process of the polymers used in electrical wiring insulation and the ways in which their dielectric properties change as the material is subject to the aging processes. The other part of the project is to determine the feasibility of a new capacitive nondestructive testing method to indicate degradation in the wiring insulation, by measuring its permittivity.

  17. Rapid, non-destructive evaluation of ultrathin WSe{sub 2} using spectroscopic ellipsometry

    SciTech Connect

    Eichfeld, Sarah M.; Lin, Yu-Chuan; Hossain, Lorraine; Eichfeld, Chad M.; Robinson, Joshua A.

    2014-09-01

    The utilization of tungsten diselenide (WSe{sub 2}) in electronic and optoelectronic devices depends on the ability to understand and control the process-property relationship during synthesis. We demonstrate that spectroscopic ellipsometry is an excellent technique for accurate, non-destructive determination of ultra-thin (<30 nm) WSe{sub 2} properties. The refractive index (n) and extinction coefficient (k) were found to be independent of thickness down to 1.3 nm, and were used to determine film thickness, which was confirmed to be within 9% of values found via atomic force microscopy. Finally, the optical bandgap was found to closely correlate with thickness, ranging from 1.2 to 1.55 eV as the WSe{sub 2} is thinned to the equivalent of 2 atomic layers.

  18. Evaluation (not validation) of quantitative models.

    PubMed Central

    Oreskes, N

    1998-01-01

    The present regulatory climate has led to increasing demands for scientists to attest to the predictive reliability of numerical simulation models used to help set public policy, a process frequently referred to as model validation. But while model validation may reveal useful information, this paper argues that it is not possible to demonstrate the predictive reliability of any model of a complex natural system in advance of its actual use. All models embed uncertainties, and these uncertainties can and frequently do undermine predictive reliability. In the case of lead in the environment, we may categorize model uncertainties as theoretical, empirical, parametrical, and temporal. Theoretical uncertainties are aspects of the system that are not fully understood, such as the biokinetic pathways of lead metabolism. Empirical uncertainties are aspects of the system that are difficult (or impossible) to measure, such as actual lead ingestion by an individual child. Parametrical uncertainties arise when complexities in the system are simplified to provide manageable model input, such as representing longitudinal lead exposure by cross-sectional measurements. Temporal uncertainties arise from the assumption that systems are stable in time. A model may also be conceptually flawed. The Ptolemaic system of astronomy is a historical example of a model that was empirically adequate but based on a wrong conceptualization. Yet had it been computerized--and had the word then existed--its users would have had every right to call it validated. Thus, rather than talking about strategies for validation, we should be talking about means of evaluation. That is not to say that language alone will solve our problems or that the problems of model evaluation are primarily linguistic. The uncertainties inherent in large, complex models will not go away simply because we change the way we talk about them. But this is precisely the point: calling a model validated does not make it valid. Modelers and policymakers must continue to work toward finding effective ways to evaluate and judge the quality of their models, and to develop appropriate terminology to communicate these judgments to the public whose health and safety may be at stake. PMID:9860904

  19. A Quantitative Evaluation of Dissolved Oxygen Instrumentation

    NASA Technical Reports Server (NTRS)

    Pijanowski, Barbara S.

    1971-01-01

    The implications of the presence of dissolved oxygen in water are discussed in terms of its deleterious or beneficial effects, depending on the functional consequences to those affected, e.g., the industrialist, the oceanographer, and the ecologist. The paper is devoted primarily to an examination of the performance of five commercially available dissolved oxygen meters. The design of each is briefly reviewed and ease or difficulty of use in the field described. Specifically, the evaluation program treated a number of parameters and user considerations including an initial check and trial calibration for each instrument and a discussion of the measurement methodology employed. Detailed test results are given relating to the effects of primary power variation, water-flow sensitivity, response time, relative accuracy of dissolved-oxygen readout, temperature accuracy (for those instruments which included this feature), error and repeatability, stability, pressure and other environmental effects, and test results obtained in the field. Overall instrument performance is summarized comparatively by chart.

  20. Quantitative evaluation of ocean thermal energy conversion (OTEC): executive briefing

    SciTech Connect

    Gritton, E.C.; Pei, R.Y.; Hess, R.W.

    1980-08-01

    Documentation is provided of a briefing summarizing the results of an independent quantitative evaluation of Ocean Thermal Energy Conversion (OTEC) for central station applications. The study concentrated on a central station power plant located in the Gulf of Mexico and delivering power to the mainland United States. The evaluation of OTEC is based on three important issues: resource availability, technical feasibility, and cost.

  1. Integrating Qualitative and Quantitative Evaluation Methods in Substance Abuse Research.

    ERIC Educational Resources Information Center

    Dennis, Michael L.; And Others

    1994-01-01

    Some specific opportunities and techniques are described for combining and integrating qualitative and quantitative methods from the design stage of a substance abuse program evaluation through implementation and reporting. The multiple problems and requirements of such an evaluation make integrated methods essential. (SLD)

  2. Quantitative evaluation fo cerebrospinal fluid shunt flow

    SciTech Connect

    Chervu, S.; Chervu, L.R.; Vallabhajosyula, B.; Milstein, D.M.; Shapiro, K.M.; Shulman, K.; Blaufox, M.D.

    1984-01-01

    The authors describe a rigorous method for measuring the flow of cerebrospinal fluid (CSF) in shunt circuits implanted for the relief of obstructive hydrocephalus. Clearance of radioactivity for several calibrated flow rates was determined with a Harvard infusion pump by injecting the Rickham reservoir of a Rickham-Holter valve system with 100 ..mu..Ci of Tc-99m as pertechnetate. The elliptical and the cylindrical Holter valves used as adjunct valves with the Rickham reservoir yielded two different regression lines when the clearances were plotted against flow rats. The experimental regression lines were used to determine the in vivo flow rates from clearances calculated after injecting the Rickham reservoirs of the patients. The unique clearance characteristics of the individual shunt systems available requires that calibration curves be derived for an entire system identical to one implanted in the patient being evaluated, rather than just the injected chamber. Excellent correlation between flow rates and the clinical findings supports the reliability of this method of quantification of CSF shunt flow, and the results are fully accepted by neurosurgeons.

  3. Non-destructive evaluation means and method of flaw reconstruction utilizing an ultrasonic multi-viewing transducer data acquistion system

    DOEpatents

    Thompson, Donald O.; Wormley, Samuel J.

    1989-03-28

    A multi-viewing ultrasound transducer acquisition system for non-destructive evaluation, flaw detection and flaw reconstruction in materials. A multiple transducer assembly includes a central transducer surrounded by a plurality of perimeter transducers, each perimeter transducer having an axis of transmission which can be angularly oriented with respect to the axis of transmission of the central transducer to intersect the axis of transmission of the central transducer. A control apparatus automatically and remotely positions the transducer assembly with respect to the material by a positioning apparatus and adjusts the pe GRANT REFERENCE This invention was conceived and reduced to practice at least in part under a grant from the Department of Energy under Contract No. W-7407-ENG-82.

  4. Non-Destructive Evaluation for Corrosion Monitoring in Concrete: A Review and Capability of Acoustic Emission Technique

    PubMed Central

    Zaki, Ahmad; Chai, Hwa Kian; Aggelis, Dimitrios G.; Alver, Ninel

    2015-01-01

    Corrosion of reinforced concrete (RC) structures has been one of the major causes of structural failure. Early detection of the corrosion process could help limit the location and the extent of necessary repairs or replacement, as well as reduce the cost associated with rehabilitation work. Non-destructive testing (NDT) methods have been found to be useful for in-situ evaluation of steel corrosion in RC, where the effect of steel corrosion and the integrity of the concrete structure can be assessed effectively. A complementary study of NDT methods for the investigation of corrosion is presented here. In this paper, acoustic emission (AE) effectively detects the corrosion of concrete structures at an early stage. The capability of the AE technique to detect corrosion occurring in real-time makes it a strong candidate for serving as an efficient NDT method, giving it an advantage over other NDT methods. PMID:26251904

  5. Nondestructive Evaluation of the Gimbal Joint Flowliner Slots in the Space Shuttle Main Propulsion System Hydrogen Feedline

    NASA Technical Reports Server (NTRS)

    Suits, Michael W.; Bryson, Craig C.

    2006-01-01

    Fatigue cracks were discovered in the STS-112 Liquid Hydrogen Feedline flowliners in 2002. This led to a development program aimed at providing nondestructive evaluation methods and techniques to verify the existence of these types of cracks in oval shaped slots cut into the ends of the feedlines above the bellows joints. These slots were used to improve flow dynamics and to facilitate cleaning in the bellow joint region. These types of fatigue cracks posed a possible metal debris ingestion threat for the Space Shuttle Main Engines, which attached to these particular joints. Results of this program produced three reliable inspection techniques utilizing the imaging of replisets with a Scanning Electron microscope, eddy current, and ultrasound. The program developed unique probes and fixtures and in the case of eddy current and ultrasound, provided qualification and certification of the particular techniques by various Design of Experiments and Probability of Detection studies utilizing multiple inspectors.

  6. Non-Destructive Evaluation for Corrosion Monitoring in Concrete: A Review and Capability of Acoustic Emission Technique.

    PubMed

    Zaki, Ahmad; Chai, Hwa Kian; Aggelis, Dimitrios G; Alver, Ninel

    2015-01-01

    Corrosion of reinforced concrete (RC) structures has been one of the major causes of structural failure. Early detection of the corrosion process could help limit the location and the extent of necessary repairs or replacement, as well as reduce the cost associated with rehabilitation work. Non-destructive testing (NDT) methods have been found to be useful for in-situ evaluation of steel corrosion in RC, where the effect of steel corrosion and the integrity of the concrete structure can be assessed effectively. A complementary study of NDT methods for the investigation of corrosion is presented here. In this paper, acoustic emission (AE) effectively detects the corrosion of concrete structures at an early stage. The capability of the AE technique to detect corrosion occurring in real-time makes it a strong candidate for serving as an efficient NDT method, giving it an advantage over other NDT methods. PMID:26251904

  7. High temperature ultrasonic transducers for the generation of guided waves for non-destructive evaluation of pipes

    SciTech Connect

    Sinding, K.; Searfass, C.; Malarich, N.; Reinhardt, B.; Tittmann, B. R.

    2014-02-18

    Applications for non-destructive evaluation and structural health monitoring of steam generators require ultrasonic transducers capable of withstanding the high temperatures of the pipes and heat exchangers. These applications require a strong coupling of the transducer to the heat exchanger’s complex geometry at the elevated temperatures. Our objective is to use spray-on piezo-electrics for depositing comb transducers onto the curved surfaces. This paper shows results for composite transducers such as lead zirconate titanate/ bismuth titanate and bismuth titanate/ lithium niobate. The comb transducers were prepared by precision laser ablation. The feasibility of producing second harmonic waves in rods with these spay-on comb transducers was demonstrated and paves the way toward measuring material degradation early-on before crack initiation occurs.

  8. Quantitative evaluation of simulated human enamel caries kinetics using photothermal radiometry and modulated luminescence

    NASA Astrophysics Data System (ADS)

    Hellen, Adam; Mandelis, Andreas; Finer, Yoav; Amaechi, Bennett T.

    2011-03-01

    Photothermal radiometry and modulated luminescence (PTR-LUM) is a non-destructive methodology applied toward the detection, monitoring and quantification of dental caries. The purpose of this study was to evaluate the efficacy of PTRLUM to detect incipient caries lesions and quantify opto-thermophysical properties as a function of treatment time. Extracted human molars (n=15) were exposed to an acid demineralization gel (pH 4.5) for 10 or 40 days in order to simulate incipient caries lesions. PTR-LUM frequency scans (1 Hz - 1 kHz) were performed prior to and during demineralization. Transverse Micro-Radiography (TMR) analysis followed at treatment conclusion. A coupled diffusephoton- density-wave and thermal-wave theoretical model was applied to PTR experimental amplitude and phase data across the frequency range of 4 Hz - 354 Hz, to quantitatively evaluate changes in thermal and optical properties of sound and demineralized enamel. Excellent fits with small residuals were observed experimental and theoretical data illustrating the robustness of the computational algorithm. Increased scattering coefficients and poorer thermophysical properties were characteristic of demineralized lesion bodies. Enhanced optical scattering coefficients of demineralized lesions resulted in poorer luminescence yield due to scattering of both incident and converted luminescent photons. Differences in the rate of lesion progression for the 10-day and 40-day samples points to a continuum of surface and diffusion controlled mechanism of lesion formation. PTR-LUM sensitivity to changes in tooth mineralization coupled with opto-thermophysical property extraction illustrates the technique's potential for non-destructive quantification of enamel caries.

  9. Nondestructive thermoelectric evaluation of the grit blasting induced effects in metallic biomaterials

    NASA Astrophysics Data System (ADS)

    Carreon, H.; Ruiz, A.; Barriuso, S.; González-Carrasco, J. L.; Caballero, F. G.; Lieblich, M.

    2013-01-01

    Grit blasting is a surface treatment process widely used to enhance mechanical fixation of the implants through increasing their roughness. Test samples of two metallic biomaterial alloys such 316LVM and Ti6Al4V were blasted by projecting Al2O3 and ZrO2 particles which yield a coarse and a fine rough surface. Then, the blasted samples were thermally treated before and after partial stress relaxation and measured by non-destructive thermoelectric techniques (NDTT), the non-contacting and contacting thermoelectric power (TEP) measurements respectively. It has been found that the TEP measurements are associated directly with the subtle material variations such as cold work and compressive residual stresses due to plastic deformation produced by grit blasting. The TEP measurements clearly demonstrate that the non-contact NDTT technique is very sensitive to the reverse transformation of the α'-martensite (blasted 316LVM) and the expected relaxation of compressive residual stresses with increasing the severity of the thermal treatment (blasted 316LVM and Ti-6Al-4V), while the contact NDTT results are closely related to grain size refinement and work hardening.

  10. Large area detector based computed tomography system for production nondestructive evaluation.

    SciTech Connect

    Keating, S. C.; Davis, A. A.; Claytor, T. N.

    2001-01-01

    We present a system for industrial x-ray computed tomography that has been optimized for all phases of nondestructive component inspection. Data acquisition is greatly enhanced by the use of high resolution, large area, flat-panel amorphous-silicon detectors. The detectors have proven, over several years, to be a robust alternative to CCD-optics and image intensifier CT systems. In addition to robustness, these detectors provide the advantage of area detection as compared with the single slice geometry of linear array systems. Parallel processing provides significant speed improvements for data reconstruction, and is implemented for parallel-beam, fan-beam and Feldkamp conebeam reconstruction algorithms. By clustering ten or more equal-speed computers, reconstruction times are reduced by an order of magnitude. We have also developed interactive software for visualization and interrogation of the full three-dimensional dataset. Inspection examples presented in this paper include an electro-mechanical device, nonliving biological specimens and a turbo-machinery component. We also present examples of everyday items for the benefit of the layperson.

  11. Shearographic and thermographic nondestructive evaluation of the space shuttle structure and thermal protection systems (TPS)

    NASA Astrophysics Data System (ADS)

    Davis, Christopher K.

    1996-11-01

    Shearography and thermography have shown promising results on orbiter structure and external tank (ET) and solid rocket booster (SRB) thermal protection systems (TPS). The orbiter uses a variety of composite structure, the two most prevalent materials being aluminum and graphite-epoxy honeycomb. Both techniques have detected delaminations as small at 0.25 inches diameter in the orbiter payload bay doors graphite-epoxy honeycomb structure. Other applications include the robotic manipulator system (RMS) and the rudder speed brake structure. The ET uses spray-on foam insulation (SOFI) as the TPS and the SRB forward section uses marshall sprayable ablative as the TPS. Debonding SOFI damage to the orbiter 'belly' tile and exposes the ET to thermal loading. Voids in SOFI test panels as small as 0.375 inch were detected in 1.75 inch thick foam using a pressure reduction of not more than 10 inches of water or 0.4 pounds per square inch. Preliminary results of the X33 metallic TPS are presented. Ultrasonic testing approved for orbiter bond integrity testing, is time consuming and problematic. No current non-destructive inspection technique is approved for inspection of ET/SRB TPS or the orbiter RMS honeycomb at Kennedy Space Center. Only visual inspections are routinely performed on orbiter structure. The various successes of these two techniques make them good candidates for the aforementioned applications.

  12. Characteristic evaluation of liquid phase-sintered SiC materials by a nondestructive technique

    NASA Astrophysics Data System (ADS)

    Lee, J. K.; Lee, S. P.; Cho, K. S.; Lee, J. H.; Kohyama, A.

    2009-04-01

    The nondestructive properties of liquid phase-sintered silicon carbide (LPS-SiC) materials were investigated by an ultrasonic method, in conjunction with the examination of their mechanical properties and microstructures. The damage behaviors of LPS-SiC materials by the cyclic thermal shock were also examined. LPS-SiC materials were fabricated at the temperature of 1820 °C, using the additives of Al 2O 3, and Y 2O 3 particles. The compositional ratios of additive materials (Al 2O 3/Y 2O 3) for LPS-SiC materials were changed from 0.4 to 1.5 with the total amount maintained at 10 wt%. The LPS-SiC materials represented a good density of about 3.2 Mg/m 3 and an average flexural strength of about 810 MPa at an additive composition ratio of 1.5. The properties of LPS-SiC materials such as density and flexural strength were more strongly correlated with the attenuation coefficient than with the velocity of ultrasonic wave. The attenuation coefficient of LPS-SiC materials also increased with the increase of thermal shock cycles, reflecting the increased microcrack density.

  13. Quantitative non-destructive testing

    NASA Technical Reports Server (NTRS)

    Welch, C. S.

    1985-01-01

    The work undertaken during this period included two primary efforts. The first is a continuation of theoretical development from the previous year of models and data analyses for NDE using the Optical Thermal Infra-Red Measurement System (OPTITHIRMS) system, which involves heat injection with a laser and observation of the resulting thermal pattern with an infrared imaging system. The second is an investigation into the use of the thermoelastic effect as an effective tool for NDE. As in the past, the effort is aimed towards NDE techniques applicable to composite materials in structural applications. The theoretical development described produced several models of temperature patterns over several geometries and material types. Agreement between model data and temperature observations was obtained. A model study with one of these models investigated some fundamental difficulties with the proposed method (the primitive equation method) for obtaining diffusivity values in plates of thickness and supplied guidelines for avoiding these difficulties. A wide range of computing speeds was found among the various models, with a one-dimensional model based on Laplace's integral solution being both very fast and very accurate.

  14. Non-Destructive Evaluation of Rock Bolts Associated With Optical Strain Sensors at the Homestake Gold Mine

    NASA Astrophysics Data System (ADS)

    Kogle, M. M.; Fratta, D.; Wang, H. F.; Geox^Tm

    2010-12-01

    Fiber-Bragg Grating (FBG) optical strain sensors have been installed in the former Homestake Gold Mine (Lead, SD) as part of an early science project at the Deep Underground Science and Engineering Laboratory (DUSEL). FBG sensors are anchored within an alcove at the 4100’ level of the mine using rock bolts and coupled to the rock mass with resin epoxy and cement grout. The quality of the coupling between the rock bolt and the rock mass is essential to assure that true rock mass strains are being recorded. To evaluate the integrity of the installed rock bolt system, guided ultrasonic waves can be used as a non-destructive monitoring system. The propagation of reflected ultrasonic waves capture information about the degree of coupling between the steel rock bolt and resin epoxy/cement grout and between the resin epoxy/cement grout and the surrounding rock mass, and hence the integrity of the installed rock bolt system. In this study, we use the phase velocity obtained from ultrasonic wave propagation to estimate the rock modulus. In our initial testing we generated a broadband elastic wave along the length of a rock bolt anchored in a concrete cylinder while monitoring multiple reflections with a single accelerometer affixed at the exposed end of the rock bolt. The captured waveforms include several reflections that were then analyzed to obtain frequency response, coherence, phase velocity, and damping between multiple reflections. As the wavelength increases, the response captures first elastic properties of the steel and then the combined elastic properties of the rock bolt/rock mass system. Challenges associated with implementing this non-destructive testing technique in rock masses include the generation of wide bandwidth signals having enough strength to produce multiple reflections with high enough signal-to-noise ratios to capture properties of multi-scale systems.

  15. Simultaneous sum-frequency and vibro-acoustography imaging for nondestructive evaluation and testing applications

    NASA Astrophysics Data System (ADS)

    Mitri, F. G.; Silva, G. T.; Greenleaf, J. F.; Fatemi, M.

    2007-12-01

    High-resolution ultrasound imaging systems for inspection of defects and flaws in materials are of great demand in many industries. Among these systems, Vibro-acoustography (VA) has shown excellent capabilities as a noncontact method for nondestructive high-resolution imaging applications. This method consists of mixing two confocal ultrasound beams, slightly shifted in frequency, to produce a dynamic (oscillatory) radiation force in the region of their intersection. This force vibrates the object placed at the focus of the confocal transducer. As a result of the applied force, an acoustic emission field at the difference frequency of the primary incident ultrasound beams is produced. In addition to the difference frequency acoustic emission signal, there exists another signal at the sum frequency, formed in the intersection region of the two primary beams. The goal of this study is to investigate the formation of high-resolution images using the sum frequency of ultrasound waves in VA while concurrently forming the conventional difference-frequency VA image, thereby increasing the amount of information acquired during a single scan. A theoretical model describing the sum-frequency wave propagation, including beam forming and image formation in the confocal configuration, is developed and verified experimentally. Moreover, sample experiments are performed on a flawed fiber-reinforced ceramic composite plate. Images at both the difference and sum frequencies are compared and discussed. Results show that the sum-frequency image produces a high-resolution C scan of the plate by which the flaws and structural details of the plate can be detected.

  16. Evaluating the Radiation From Accidental Exposure During a Nondestructive Testing Event.

    PubMed

    Ting, Chien-Yi; Wang, Hsin-Ell; Lin, Jao-Perng; Lin, Chun-Chih

    2015-08-01

    Industrial radiography is a common nondestructive testing (NDT) method used in various industries. An investigation was conducted for a 1999 incident in Taiwan where two workers (Operators A and B) were accidently exposed to an unshielded Ir source while conducting industrial radiography. Operators A and B experienced acute close-range radiation exposure to a source of Ir for 3 h at a strength of 2.33 × 10 Bq. The health of mammary glands, bone marrow, thyroid glands, eyes, and genital organs of these two workers after radiation exposure was examined. Subsequently, Operator A experienced severe radiation injury, including tissue necrosis and keratinization in the fingers, chromosomal abnormalities, reduced blood cell count, diffuse hyperplasia of the thyroid gland, opaque spots in the crystalline lens, and related radiation effects. The results showed that the left index finger and thumb, eyes, and gonads of Operator A were exposed to a radiation dose of about 369-1,070, 23.1-67.4, 2.4-5.3, and 4.2-11.6 Gy, respectively. Effective dose for Operator A was estimated to range from 6.9 to 18.9 Sv. The left fingers, thumb, eyes, and gonads of Operator B were exposed to a radiation dose of 184.9-646.2, 11.8-40.7, 0.49-3.33, and 0.72-7.18 Gy, respectively, and his effective dose was between 2.5 and 11.5 Sv. This accident indicated a major flaw in the control and regulation of radiation safety for conducting NDT industrial radiography in 1999; however, similar problems still exist. Modifications of the Ionizing Radiation Protection Act in Taiwan are suggested in this study to regulate the management of NDT industries, continually educate the NDT workers in radiation safety, and enact notification provisions for medical care systems toward acute radiation exposure events. PMID:26107437

  17. Ultrasonic imaging algorithms with limited transmission cycles for rapid nondestructive evaluation.

    PubMed

    Moreau, Ludovic; Drinkwater, Bruce W; Wilcox, Paul D

    2009-09-01

    Imaging algorithms recently developed in ultrasonic nondestructive testing (NDT) have shown good potential for defect characterization. Many of them are based on the concept of collecting the full matrix of data, obtained by firing each element of an ultrasonic phased array independently, while collecting the data with all elements. Because of the finite sound velocity in the test structure, 2 consecutive firings must be separated by a minimum time interval. Depending on the number of elements in a given array, this may become problematic if data must be collected within a short time, as it is often the case, for example, in an industrial context. An obvious way to decrease the duration of data capture is to use a sparse transmit aperture, in which only a restricted number of elements are used to transmit ultrasonic waves. This paper compares 2 approaches aimed at producing an image on the basis of restricted data: the common source method and the effective aperture technique. The effective aperture technique is based on the far-field approximation, and no similar approach exists for the near-field. This paper investigates the performance of this technique in near-field conditions, where most NDT applications are made. First, these methods are described and their point spread functions are compared with that of the Total Focusing Method (TFM), which consists of focusing the array at every point in the image. Then, a map of efficiency is given for the different algorithms in the near-field. The map can be used to select the most appropriate algorithm. Finally, this map is validated by testing the different algorithms on experimental data. PMID:19811996

  18. A quantitative method for evaluating alternatives. [aid to decision making

    NASA Technical Reports Server (NTRS)

    Forthofer, M. J.

    1981-01-01

    When faced with choosing between alternatives, people tend to use a number of criteria (often subjective, rather than objective) to decide which is the best alternative for them given their unique situation. The subjectivity inherent in the decision-making process can be reduced by the definition and use of a quantitative method for evaluating alternatives. This type of method can help decision makers achieve degree of uniformity and completeness in the evaluation process, as well as an increased sensitivity to the factors involved. Additional side-effects are better documentation and visibility of the rationale behind the resulting decisions. General guidelines for defining a quantitative method are presented and a particular method (called 'hierarchical weighted average') is defined and applied to the evaluation of design alternatives for a hypothetical computer system capability.

  19. Application of low-coherence interferometry for in situ nondestructive evaluation of thin and thick multilayered transparent composites

    NASA Astrophysics Data System (ADS)

    Khomenko, Anton; Cloud, Gary Lee; Haq, Mahmoodul

    2015-12-01

    Multilayered transparent composites having laminates with polymer interlayers and backing sheets are commonly used in a wide range of applications where visibility, transparency, impact resistance, and safety are essential. Manufacturing flaws or damage during operation can seriously compromise both safety and performance. Most fabrication defects are not discernible until after the entire multilayered transparent composite assembly has been completed, and in-the-field inspection for damage is a problem not yet solved. A robust and reliable nondestructive evaluation (NDE) technique is needed to evaluate structural integrity and identify defects that result from manufacturing issues as well as in-service damage arising from extreme environmental conditions in addition to normal mechanical and thermal loads. Current optical techniques have limited applicability for NDE of such structures. This work presents a technique that employs a modified interferometer utilizing a laser diode or femtosecond fiber laser source to acquire in situ defect depth location inside a thin or thick multilayered transparent composite, respectively. The technique successfully located various defects inside examined composites. The results show great potential of the technique for defect detection, location, and identification in multilayered transparent composites.

  20. Waterless Coupling of Ultrasound from Planar Contact Transducers to Curved and Irregular Surfaces during Non-destructive Ultrasonic Evaluations

    SciTech Connect

    Denslow, Kayte M.; Diaz, Aaron A.; Jones, Anthony M.; Meyer, Ryan M.; Cinson, Anthony D.; Wells, Mondell D.

    2012-04-30

    The Applied Physics group at the Pacific The Applied Physics group at the Pacific Northwest National Laboratory (PNNL) in Richland, WA has evaluated a method for waterless/liquidless coupling of ultrasonic energy from planar ultrasonic contact transducers to irregular test surfaces for ultrasonic non-destructive evaluation applications. Dry couplant material placed between a planar transducer face and a curved or uneven steel or plastic surface allows for effective sound energy coupling and preserves the integrity of the planar transducer sound field by serving as an acoustic impedance matching layer, providing good surface area contact between geometrically dissimilar surfaces and conforming to rough and unsmooth surfaces. Sound fields radiating from planar ultrasonic contact transducers coupled to curved and uneven surfaces using the dry coupling method were scanned and mapped using a Pinducer receiver connected to a raster scanner. Transducer sound field coverage at several ultrasonic frequencies and several distances from the transducer contact locations were found to be in good agreement with theoretical beam divergence and sound field coverage predictions for planar transducers coupled to simple, planar surfaces. This method is valuable for applications that do not allow for the use of traditional liquid-based ultrasonic couplants due to the sensitivity of the test materials to liquids and for applications that might otherwise require curved transducers or custom coupling wedges. The selection of dry coupling material is reported along with the results of theoretical sound field predictions, the laboratory testing apparatus and the empirical sound field data.

  1. A model-based method for the characterisation of stress in magnetic materials using eddy current non-destructive evaluation

    NASA Astrophysics Data System (ADS)

    Dahia, Abla; Berthelot, Eric; Le Bihan and, Yann; Daniel, Laurent

    2015-03-01

    A precise knowledge of the distribution of internal stresses in materials is key to the prediction of magnetic and mechanical performance and lifetime of many industrial devices. This is the reason why many efforts have been made to develop and enhance the techniques for the non-destructive evaluation of stress. In the case of magnetic materials, the use of eddy current (EC) techniques is a promising pathway to stress evaluation. The principle is based on the significant changes in magnetic permeability of magnetic materials subjected to mechanical stress. These modifications of magnetic permeability affect in turn the signal obtained from an EC probe inspecting the material. From this principle, a numerical tool is proposed in this paper to predict the EC signal obtained from a material subjected to stress. This numerical tool is a combination of a 3D finite element approach with a magneto-mechanical constitutive law describing the effect of stress on the magnetic permeability. The model provides the variations of impedance of an EC probe as a function of stress. An experimental setup in which a magnetic material subjected to a tension stress is inspected using EC techniques is tailored in order to validate the model. A very good agreement is found between experimental and modelling results. For the Iron-Cobalt alloy tested in this study, it is shown that a uniaxial tensile stress can be detected with an error lower than 3 MPa in the range from 0 to 100 MPa.

  2. Reference Specimen for Nondestructive Evaluation: Characterization of the Oxide Layer of a Cold Shot in Inconel 600

    NASA Astrophysics Data System (ADS)

    Saletes, I.; Filleter, T.; Goldbaum, D.; Chromik, R. R.; Sinclair, A. N.

    2015-02-01

    The presence of a cold shot in an aircraft turbine blade can lead to the catastrophic failure of the blade and ultimately to the failure of the power plant. Currently, no nondestructive evaluation (NDE) method exists to detect this kind of defect. This deficiency is primarily due to the fact that the only known cold shot defects in existence are those found in failed blades. Therefore, in order to develop effective NDE methods, reference specimens are needed which mimic the embedded oxide layer that is a primary distinguishing feature of a cold shot. Here, we present a procedure to synthetically reproduce the features of a real cold shot in Inconel 600 and the precise characterization of this oxide layer as a reference specimen suitable for NDE evaluation. As a first step to develop a suitable NDE technique, high-frequency ultrasound simulations are considered. A theoretical 1-D model is developed in order to quantify the multiple reflection-transmission trajectory of the acoustic wave in the reference specimen. This paper also presents an experimental determination of the density and the Young's modulus of the Inconel 600 oxide, which are required as inputs to calculate the acoustic impedance used in the theoretical model.

  3. Guidelines to Evaluate Human Observational Studies for Quantitative Risk Assessment

    PubMed Central

    Vlaanderen, Jelle; Vermeulen, Roel; Heederik, Dick; Kromhout, Hans

    2008-01-01

    Background Careful evaluation of the quality of human observational studies (HOS) is required to assess the suitability of HOS for quantitative risk assessment (QRA). In particular, the quality of quantitative exposure assessment is a crucial aspect of HOS to be considered for QRA. Objective We aimed to develop guidelines for the evaluation of HOS for QRA and to apply these guidelines to case–control and cohort studies on the relation between exposure to benzene and acute myeloid leukemia (AML). Methods We developed a three-tiered framework specific for the evaluation of HOS for QRA and used it to evaluate HOS on the relation between exposure to benzene and AML. Results The developed framework consists of 20 evaluation criteria. A specific focus of the framework was on the quality of exposure assessment applied in HOS. Seven HOS on the relation of benzene and AML were eligible for evaluation. Of these studies, five were suitable for QRA and were ranked based on the quality of the study design, conduct, and reporting on the study. Conclusion The developed guidelines facilitate a structured evaluation that is transparent in its application and harmonizes the evaluation of HOS for QRA. With the application of the guidelines, it was possible to identify studies suitable for QRA of benzene and AML and rank these studies based on their quality. Application of the guidelines in QRA will be a valuable addition to the assessment of the weight of evidence of HOS for QRA. PMID:19079723

  4. Innovative non-destructive evaluation methods on HTR fuel at AREVA NP: towards a 100% non invasive control strategy

    SciTech Connect

    Banchet, J.; Tisseur, D.; Hermosilla Lara, S.; Piriou, M.; Bargain, R.; Guillermier, P.

    2007-07-01

    High Temperature Reactor (HTR) fuel consists in millimetric multilayered particles called TRISO, embedded, depending on the reactor design, in a pebble or cylinder-shaped graphite matrix called compact. Particles are typically composed of a 500 {mu}m fissile material kernel, a 95 {mu}m porous carbon layer called buffer, a 40 {mu}m dense pyrolytic carbon layer, a 35 {mu}m silicon carbide layer and another 40 {mu}m dense pyrolytic carbon layer. In order to ensure fuel qualification, as well as reactor safety, particles and compacts need to satisfy specifications concerning their physical characteristics and their integrity. In particular, geometrical parameters such as particle diameter and sphericity as well as layers thickness, but also layers density and the absence of structural defects such as cracks or de-cohesions need to be detected and characterized. In the past, a huge R and D work was carried out to build a TRISO particle characterization quality control plan, mainly based on particle sampling as well as destructive characterization methods. However, since then, development of industrial non-destructive evaluation techniques and devices contributed to envisage not only a non invasive control of HTR fuel, but also a 100% production control strategy. Since 2004, AREVA NP is engaged in a R and D program aiming at the development of innovative industrial nondestructive evaluation methods for HTR fuel. After investigating a number of potential techniques, some of them were selected based on their performances and/or their industrial potential. In particular, development has been carried out on high resolution X-Ray imaging allowing accurate layer thickness, layer density and structural defects characterization, X-Ray tomography offering the possibility to characterize fuel element homogeneity and determine the number of in-contact particles contained in a fuel element, infrared thermal imaging (ITI) allowing cracks detection, eddy currents (EC) enabling particle diameter measurements as well as crack detection and vision enabling real time automatic crack detection. These techniques were selected either for the richness of their information (X-Ray, tomography), or because of their high throughput rate (ITI, EC). For all these techniques, besides the development of a HTR fuel dedicated control method, equipment and probes were specifically designed, tested and optimized to obtain, in particular for ITI and EC, throughput rates that are compatible with a 100% production control strategy. (authors)

  5. Highlights of NASA's Role in Developing State-of-the-Art Nondestructive Evaluation for Composites

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Since the 1970's, when the promise of composites was being pursued for aeronautics applications, NASA has had programs that addressed the development of NDE methods for composites. These efforts included both microscopic and macroscopic NDE. At the microscopic level, NDE investigations interrogated composites at the submicron to micron level to understand a composite's microstructure. A novel microfocus CT system was developed as well as the science underlying applications of acoustic microscopy to a composite's component material properties. On the macroscopic scale NDE techniques were developed that advanced the capabilities to be faster and more quantitative. Techniques such as stiffness imaging, ultrasonic arrays, laser based ultrasound, advanced acoustic emission, thermography, and novel health monitoring systems were researched. Underlying these methods has been a strong modeling capability that has aided in method development.

  6. Non-destructive evaluation of nano-sized structure of thin film devices by using small angle neutron scattering.

    PubMed

    Shin, E J; Seong, B S; Choi, Y; Lee, J K

    2011-01-01

    Nano-sized multi-layers copper-doped SrZrO3, platinum (Pt) and silicon oxide (SiO2) on silicon substrates were prepared by dense plasma focus (DPF) device with the high purity copper anode tip and analyzed by using small angle neutron scattering (SANS) to establish a reliable method for the non-destructive evaluation of the under-layer structure. Thin film was well formed at the time-to-dip of 5 microsec with stable plasma of DPF. Several smooth intensity peaks were periodically observed when neutron beam penetrates the thin film with multi-layers perpendicularly. The platinum layer is dominant to intensity peaks, where the copper-doped SrZnO3 layer next to the platinum layer causes peak broadening. The silicon oxide layer has less effect on the SANS spectra due to its relative thick thickness. The SANS spectra shows thicknesses of platinum and copper-doped SrZnO3 layers as 53 and 25 nm, respectively, which are well agreement with microstructure observation. PMID:21446565

  7. Passive and active tagging of reinforced composites for in-process and in-field nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Giurgiutiu, Victor; Chen, Zao; Lalande, Frederic; Rogers, Craig A.; Quattrone, Robert; Berman, Justin

    1996-05-01

    Conventional non-destructive evaluation (NDE) methods are not very effective in monitoring the material conditions of advanced composite and adhesive joints. A technology that has been proposed to enhance the inspectability of advanced composites is the particle tagging technique. Two theoretical models were recently proposed to characterize the dynamic behavior of ferromagnetic and magnetostrictive tagging particles. These theoretical models concerning the development of an active tagging technique with embedded ferromagnetic and magnetostrictive particles and magnetic excitation are now experimentally verified. The experimental results of the active particle tagging shows a variation in the dynamic response of the specimens when defects and/or damage are present. The sensory signature from a tagged polymer is extracted as a result of the interaction between the embedded particles and their host matrix. A study of various types of composites and tagging particles for passive and active tagging was performed. Experimental validation of concepts for tagging of structural materials for on-site inspection prior to installation have also been explored. The on-site particle tagging inspection has been verified on laboratory specimens obtained from industry and was shown to be very efficient.

  8. Non-destructive evaluation of degradation in EB-PVD thermal barrier coatings by infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Flattum, Richard Y.; Cooney, Adam T.

    2013-01-01

    At room temperature and atmospheric conditions infrared reflectance spectroscopy and X-ray diffraction were employed for the detection of the phase transformation and residual stress within thermal barrier coatings (TBC). The TBC's samples initially consisted of the porous ceramic topcoat deposited by electron beam plasma vapor deposition, a bond coat and a superalloy substrate. Reflectance spectroscopy scans were performed from 7497 cm-1 to 68 cm-1 to analysis the fingerprint region as well as the chemical bonding region. These regions should indicate if a detectable change within the TBC response is a result of thermal degradation of the microstructure and the changes in yttrium dispersion throughout the yttrium stabilized zirconium. The thermal degradation was induced by thermal cycling the samples to 1100° C and then cooling them in an atmospheric environment. X-ray diffraction was also used to detect the phase composition within the TBC samples and see if either would clearly identify failure prior to actual spallation. The eventual measurability and quantify-ability of the phase changes within the TBC's may be used as an effective non-destructive evaluation (NDE) technique that would allow personnel in the field to know when servicing of the turbine blade was necessary.

  9. Non-destructive evaluation of degradation in EB-PVD thermal barrier coatings by infrared reflectance spectroscopy

    SciTech Connect

    Flattum, Richard Y.; Cooney, Adam T.

    2013-01-25

    At room temperature and atmospheric conditions infrared reflectance spectroscopy and X-ray diffraction were employed for the detection of the phase transformation and residual stress within thermal barrier coatings (TBC). The TBC's samples initially consisted of the porous ceramic topcoat deposited by electron beam plasma vapor deposition, a bond coat and a superalloy substrate. Reflectance spectroscopy scans were performed from 7497 cm{sup -1} to 68 cm{sup -1} to analysis the fingerprint region as well as the chemical bonding region. These regions should indicate if a detectable change within the TBC response is a result of thermal degradation of the microstructure and the changes in yttrium dispersion throughout the yttrium stabilized zirconium. The thermal degradation was induced by thermal cycling the samples to 1100 Degree-Sign C and then cooling them in an atmospheric environment. X-ray diffraction was also used to detect the phase composition within the TBC samples and see if either would clearly identify failure prior to actual spallation. The eventual measurability and quantify-ability of the phase changes within the TBC's may be used as an effective non-destructive evaluation (NDE) technique that would allow personnel in the field to know when servicing of the turbine blade was necessary.

  10. Method Developed for the High-Temperature Nondestructive Evaluation of Fiber-Reinforced Silicon Carbide Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Goldsby, Jon C.

    1998-01-01

    Ceramic matrix composites have emerged as candidate materials to allow higher operating temperatures (1000 to 1400 C) in gas turbine engines. A need, therefore, exists to develop nondestructive methods to evaluate material integrity at the material operating temperature by monitoring thermal and mechanical fatigue. These methods would also have potential as quality inspection tools. The goal of this investigation at the NASA Lewis Research Center is to survey and correlate the temperature-dependent damping and stiffness of advanced ceramic composite materials with imposed thermal and stress histories that simulate in-service turbine engine conditions. A typical sample size of 100 by 4 by 2 cubic millimeters, along with the specified stiffness and density, placed the fundamental vibration frequencies between 100 and 2000 Hz. A modified Forster apparatus seemed most applicable to simultaneously measure both damping and stiffness. Testing in vacuum reduced the effects of air on the measurements. In this method, a single composite sample is vibrated at its fundamental tone; then suddenly, the mechanical excitation is removed so that the sample's motion freely decays with time. Typical results are illlustrated in this paper.

  11. Roadmap for Nondestructive Evaluation of Reactor Pressure Vessel Research and Development by the Light Water Reactor Sustainability Program

    SciTech Connect

    Smith, Cyrus M; Nanstad, Randy K; Clayton, Dwight A; Matlack, Katie; Ramuhalli, Pradeep; Light, Glenn

    2012-09-01

    The Department of Energy s (DOE) Light Water Reactor Sustainability (LWRS) Program is a five year effort which works to develop the fundamental scientific basis to understand, predict, and measure changes in materials and systems, structure, and components as they age in environments associated with continued long-term operations of existing commercial nuclear power reactors. This year, the Materials Aging and Degradation (MAaD) Pathway of this program has placed emphasis on emerging Non-Destructive Evaluation (NDE) methods which support these objectives. DOE funded Research and Development (R&D) on emerging NDE techniques to support commercial nuclear reactor sustainability is expected to begin next year. This summer, the MAaD Pathway invited subject matter experts to participate in a series of workshops which developed the basis for the research plan of these DOE R&D NDE activities. This document presents the results of one of these workshops which are the DOE LWRS NDE R&D Roadmap for Reactor Pressure Vessels (RPV). These workshops made a substantial effort to coordinate the DOE NDE R&D with that already underway or planned by the Electric Power Research Institute (EPRI) and the Nuclear Regulatory Commission (NRC) through their representation at these workshops.

  12. Ultrasonic Imaging Technology Helps American Manufacturer of Nondestructive Evaluation Equipment Become More Competitive in the Global Market

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Sonix, Inc., of Springfield, Virginia, has implemented ultrasonic imaging methods developed at the NASA Lewis Research Center. These methods have heretofore been unavailable on commercial ultrasonic imaging systems and provide significantly more sensitive material characterization than conventional high-resolution ultrasonic c-scanning. The technology transfer is being implemented under a cooperative agreement between NASA and Sonix, and several invention disclosures have been submitted by Dr. Roth to protect Lewis interests. Sonix has developed ultrasonic imaging systems used worldwide for microelectronics, materials research, and commercial nondestructive evaluation (NDE). In 1993, Sonix won the U.S. Department of Commerce "Excellence in Exporting" award. Lewis chose to work with Sonix for two main reasons: (1) Sonix is an innovative leader in ultrasonic imaging systems, and (2) Sonix was willing to apply the improvements we developed with our in-house Sonix equipment. This symbiotic joint effort has produced mutual benefits. Sonix recognized the market potential of our new and highly sensitive methods for ultrasonic assessment of material quality. We, in turn, see the cooperative effort as an effective means for transferring our technology while helping to improve the product of a domestic firm.

  13. Improved detection of rough defects for ultrasonic nondestructive evaluation inspections based on finite element modeling of elastic wave scattering.

    PubMed

    Pettit, James R; Walker, Anthony E; Lowe, Michael J S

    2015-10-01

    Defects which possess rough surfaces greatly affect ultrasonic wave scattering behavior, usually reducing the magnitude of reflected signals. Understanding and accurately predicting the influence of roughness on signal amplitudes is crucial, especially in nondestructive evaluation (NDE) for the inspection of safety-critical components. An extension of Kirchhoff theory has formed the basis for many practical applications; however, it is widely recognized that these predictions are pessimistic because of analytical approximations. A numerical full-field modeling approach does not fall victim to such limitations. Here, a finite element (FE) modeling approach is used to develop a realistic methodology for the prediction of expected backscattering from rough defects. The ultrasonic backscatter from multiple rough surfaces defined by the same statistical class is calculated for normal and oblique incidence. Results from FE models are compared with Kirchhoff theory predictions and experimental measurements to establish confidence in the new approach. At lower levels of roughness, excellent agreement is observed between Kirchhoff theory, FE, and experimental data, whereas at higher values, the pessimism of Kirchhoff theory is confirmed. An important distinction is made between the total, coherent, and diffuse signals and it is observed, significantly, that the total signal amplitude is representative of the information obtained during an inspection. This analysis provides a robust basis for a less sensitive, yet safe, threshold for inspection of rough defects. PMID:26470042

  14. Quantitatively evaluating the CBM reservoir using logging data

    NASA Astrophysics Data System (ADS)

    Liu, Zhidi; Zhao, Jingzhou

    2016-02-01

    In order to evaluate coal bed methane (CBM) reservoirs, this paper select five parameters: porosity, permeability, CBM content, the coal structure index and effective thickness of the coal seam. Making full use of logging and the laboratory analysis data of a coal core, the logging evaluation methods of the five parameters were discussed in detail, and the comprehensive evaluation model of the CBM reservoir was established. The #5 coal seam of the Hancheng mine on the eastern edge of the Ordos Basin in China was quantitatively evaluated using this method. The results show that the CBM reservoir in the study area is better than in the central and northern regions. The actual development of CBM shows that the region with a good reservoir has high gas production—indicating that the method introduced in this paper can evaluate the CBM reservoir more effectively.

  15. Non-destructive evaluation techniques, high temperature ceramic component parts for gas turbines

    NASA Technical Reports Server (NTRS)

    Reiter, H.; Hirsekorn, S.; Lottermoser, J.; Goebbels, K.

    1984-01-01

    This report concerns studies conducted on various tests undertaken on material without destroying the material. Tests included: microradiographic techniques, vibration analysis, high-frequency ultrasonic tests with the addition of evaluation of defects and structure through analysis of ultrasonic scattering data, microwave tests and analysis of sound emission.

  16. Time Domain Terahertz Non-Destructive Evaluation of Aeroturbine Blade Thermal Barrier Coatings

    NASA Astrophysics Data System (ADS)

    White, Jeffrey; Fichter, G.; Chernovsky, A.; Whitaker, John F.; Das, D.; Pollock, Tresa M.; Zimdars, David

    2009-03-01

    Time domain terahertz (TD-THz) non destructive evaluation (NDE) imaging is used to two-dimensionally map the thickness of yttria stabilized zirconia (YSZ) thermal barrier coatings (TBC) on aircraft engine turbine blades. Indications of thermal degradation can be seen. The method is non-contact, rapid, and requires no special preparation of the blade.

  17. Development and applications of nondestructive evaluation at Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Whitaker, Ann F.

    1990-01-01

    A brief description of facility design and equipment, facility usage, and typical investigations are presented for the following: Surface Inspection Facility; Advanced Computer Tomography Inspection Station (ACTIS); NDE Data Evaluation Facility; Thermographic Test Development Facility; Radiographic Test Facility; Realtime Radiographic Test Facility; Eddy Current Research Facility; Acoustic Emission Monitoring System; Advanced Ultrasonic Test Station (AUTS); Ultrasonic Test Facility; and Computer Controlled Scanning (CONSCAN) System.

  18. Relationship between non-destructive OCT evaluation of resins composites and bond strength in a cavity

    NASA Astrophysics Data System (ADS)

    Bakhsh, T. A.; Sadr, A.; Shimada, Y.; Khunkar, S.; Tagami, J.; Sumi, Y.

    2012-01-01

    Objectives: Formation of microgaps under the composite restorations due to polymerization stress and other causes compromise the adhesion to the dental substrate and restoration durability. However, the relationship between cavity adaptation and bond strength is not clear. In this paper, we introduce a new testing method to assess cavity adaptation by swept-source optical coherence tomography (SS-OCT) and microtensile bond strength (MTBS) in the same class-I cavity. Methods: Round class-I cavities 3 mm in diameter and 1.5 mm in depth were prepared on 10 human premolars. After application of Tokuyama Bond Force adhesive, the cavities were filled by one of the two techniques; incremental technique using Estelite Sigma Quick universal composite or flowable lining using Palfique Estelite LV with bulk filling using the universal composite. Ten serial B-scan images were obtained throughout each cavity by SS-OCT. Significant peaks in the signal intensity were detected at the bonded interface of the cavity floor and to compare the different filling techniques. The specimens were later cut into beams (0.7x0.7 mm) and tested to measure MTBS at the cavity floor. Results: Flowable lining followed by bulk filling was inferior in terms of cavity adaptation and MTBS compared to the incremental technique (p<0.05, t-test). The adaptation (gap free cavity floor) and MTBS followed similar trends in both groups. Conclusion: Quantitative assessment of dental restorations by OCT can provide additional information on the performance and effectiveness of dental composites and restoration techniques. This study was supported by Global Center of Excellence, Tokyo Medical and Dental University and King Abdulaziz University.

  19. Geometrical optimization of sensors for eddy currents nondestructive testing and evaluation

    SciTech Connect

    Thollon, F.; Burais, N.

    1995-05-01

    Design of Non Destructive Testing (NDT) and Non Destructive Evaluation (NDE) sensors is possible by solving Maxwell`s relations with FEM or BIM. But the large number of geometrical and electrical parameters of sensor and tested material implies many results that don`t give necessarily a well adapted sensor. The authors have used a genetic algorithm for automatic optimization. After having tested this algorithm with analytical solution of Maxwell`s relations for cladding thickness measurement, the method has been implemented in finite element package.

  20. Portable microwave instrument for non-destructive evaluation of structural characteristics

    DOEpatents

    Bible, Don W.; Crutcher, Richard I.; Sohns, Carl W.; Maddox, Stephen R.

    1995-01-01

    A portable microwave instrument for evaluating characteristics of a structural member includes a source of microwave energy, a transmitter coupled to the source of microwave energy for transmitting a microwave signal at the structural member, and a receiver positioned on the same side of the structural member as the transmitter and being disposed to receive a microwave signal reflected by the structural member. A phase angle difference is determined between the transmitted microwave signal and the received microwave signal using a signal splitter and a balanced mixer. The difference in phase angle varies in accordance with differences in size, shape and locations of constituent materials within the structural member.

  1. Portable microwave instrument for non-destructive evaluation of structural characteristics

    DOEpatents

    Bible, D.W.; Crutcher, R.I.; Sohns, C.W.; Maddox, S.R.

    1995-01-24

    A portable microwave instrument for evaluating characteristics of a structural member includes a source of microwave energy, a transmitter coupled to the source of microwave energy for transmitting a microwave signal at the structural member, and a receiver positioned on the same side of the structural member as the transmitter and being disposed to receive a microwave signal reflected by the structural member. A phase angle difference is determined between the transmitted microwave signal and the received microwave signal using a signal splitter and a balanced mixer. The difference in phase angle varies in accordance with differences in size, shape and locations of constituent materials within the structural member. 6 figures.

  2. Nondestructive equipment study

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Identification of existing nondestructive Evaluation (NDE) methods that could be used in a low Earth orbit environment; evaluation of each method with respect to the set of criteria called out in the statement of work; selection of the most promising NDE methods for further evaluation; use of selected NDE methods to test samples of pressure vessel materials in a vacuum; pressure testing of a complex monolythic pressure vessel with known flaws using acoustic emissions in a vacuum; and recommendations for further studies based on analysis and testing are covered.

  3. Comparison between beamforming and super resolution imaging algorithms for non-destructive evaluation

    SciTech Connect

    Fan, Chengguang; Drinkwater, Bruce W.

    2014-02-18

    In this paper the performance of total focusing method is compared with the widely used time-reversal MUSIC super resolution technique. The algorithms are tested with simulated and experimental ultrasonic array data, each containing different noise levels. The simulated time domain signals allow the effects of array geometry, frequency, scatterer location, scatterer size, scatterer separation and random noise to be carefully controlled. The performance of the imaging algorithms is evaluated in terms of resolution and sensitivity to random noise. It is shown that for the low noise situation, time-reversal MUSIC provides enhanced lateral resolution when compared to the total focusing method. However, for higher noise levels, the total focusing method shows robustness, whilst the performance of time-reversal MUSIC is significantly degraded.

  4. Evaluation of bonds in armor plate and other materials using infrared nondestructive testing techniques.

    PubMed

    Vogel, P E

    1968-09-01

    Reported here are the results of using an ir technique in evaluating the bond in hot-roll bonded armor plate, a coating bond, and the bonds in the three-layer construction of a small missile motor. When a specimen is exposed to heat, the heat flows into it at a rate that can be determined. If the flow is interrupted by a void, the inclusion of a material of different conductivity, or any similar thermal barrier, a difference in surface temperature will result that can be defined with an ir radiometer or thermograph. Lack of bond, while not presenting a gross void, is shown here to be a sufficient impediment to be distinguishable. PMID:20068876

  5. Comparison between beamforming and super resolution imaging algorithms for non-destructive evaluation

    NASA Astrophysics Data System (ADS)

    Fan, Chengguang; Drinkwater, Bruce W.

    2014-02-01

    In this paper the performance of total focusing method is compared with the widely used time-reversal MUSIC super resolution technique. The algorithms are tested with simulated and experimental ultrasonic array data, each containing different noise levels. The simulated time domain signals allow the effects of array geometry, frequency, scatterer location, scatterer size, scatterer separation and random noise to be carefully controlled. The performance of the imaging algorithms is evaluated in terms of resolution and sensitivity to random noise. It is shown that for the low noise situation, time-reversal MUSIC provides enhanced lateral resolution when compared to the total focusing method. However, for higher noise levels, the total focusing method shows robustness, whilst the performance of time-reversal MUSIC is significantly degraded.

  6. A comparison between ultrasonic array beamforming and super resolution imaging algorithms for non-destructive evaluation.

    PubMed

    Fan, Chengguang; Caleap, Mihai; Pan, Mengchun; Drinkwater, Bruce W

    2014-09-01

    In this paper the total focusing method, the so called gold standard in classical beamforming, is compared with the widely used time-reversal MUSIC super resolution technique in terms of its ability to resolve closely spaced scatterers in a solid. The algorithms are tested with simulated and experimental array data, each containing different noise levels. The performance of the algorithms is evaluated in terms of lateral resolution and sensitivity to noise. It is shown that for the weak noise situation (SNR>20 dB), time-reversal MUSIC provides significantly enhanced lateral resolution when compared to the total focusing method, breaking the diffraction limit. However, for higher noise levels, the total focusing method is shown to be robust, whilst the performance of time-reversal MUSIC is degraded. The influence of multiple scattering on the imaging algorithms is also investigated and shown to be small. PMID:24457032

  7. Non-destructive evaluation of polyethylene pipe joints using Leaky Lamb waves

    SciTech Connect

    Agnone, A.; Jensen, R.; Brassard, M.

    1995-12-31

    Polyethylene (PE) pipes have been used for nearly two decades in gas distribution systems. The pipes are joined by heating the ends above the melt temperature of PE and then press forging them together and air cooling. Visual inspection of the joint is used in the field to assess the integrity of the weld. Standard Xerographic (X-ray) tests cannot be performed on plastic pipes and NDE evaluation of the weld doesn`t exist. Field data show that about 0.5% of the fusions fail. The objective of this project is to develop an NDE test for use in the field to evaluate the integrity of butt joined PE pipes. Tests using Leaky Lamb waves (LLW) were explored to measure the elastic properties of the PE virgin and weld material. The phase velocity plots for the virgin PE material (Drisco pipe) indicate that frequencies less than 300 kHz are needed to excite Lamb waves in the PE specimen. Young`s and shear moduli were found to be G = 34,119.4 psi and E = 99,819.7 psi, respectively. Young`s modulus and yield stress determined from stress-strain curves using standard tension test agreed with the LLW results and manufacturer`s specifications. Sonograms of PE fusion specimen were also taken. The photographs show the weld region and flaws. To better identify flaws the images can be improved by optimizing the equipment for use with plastic pipes. The primary difficulties with LLW using a single probe are the effect of the radius of the pipe and the geometry of the bead. The apparatus is being modified to insonify the joint uniformity to direct the LLW waves along the pipe towards the weld. A transducer array that uses a {open_quotes}sonic brush{close_quotes} is being designed.

  8. Nondestructive analysis and development

    NASA Technical Reports Server (NTRS)

    Moslehy, Faissal A.

    1993-01-01

    This final report summarizes the achievements of project #4 of the NASA/UCF Cooperative Agreement from January 1990 to December 1992. The objectives of this project are to review NASA's NDE program at Kennedy Space Center (KSC) and recommend means for enhancing the present testing capabilities through the use of improved or new technologies. During the period of the project, extensive development of a reliable nondestructive, non-contact vibration technique to determine and quantify the bond condition of the thermal protection system (TPS) tiles of the Space Shuttle Orbiter was undertaken. Experimental modal analysis (EMA) is used as a non-destructive technique for the evaluation of Space Shuttle thermal protection system (TPS) tile bond integrity. Finite element (FE) models for tile systems were developed and were used to generate their vibration characteristics (i.e. natural frequencies and mode shapes). Various TPS tile assembly configurations as well as different bond conditions were analyzed. Results of finite element analyses demonstrated a drop in natural frequencies and a change in mode shapes which correlate with both size and location of disbond. Results of experimental testing of tile panels correlated with FE results and demonstrated the feasibility of EMA as a viable technique for tile bond verification. Finally, testing performed on the Space Shuttle Columbia using a laser doppler velocimeter demonstrated the application of EMA, when combined with FE modeling, as a non-contact, non-destructive bond evaluation technique.

  9. Simple applications of nondestructive evaluation with low-cost uncooled IR cameras

    NASA Astrophysics Data System (ADS)

    Mourand, David; Batsale, Jean-Christophe

    2001-03-01

    New low cost uncooled infrared devices (such as PalmIR 250 (Raytheon), Thermacam 540 (FLIR), Indigo...) are giving new possibilities for small or medium sized companies. Even if each pixel of the temperature image is noisy, even if the global signal is randomly shifted due to the technology of ferromagnetic or bolometric detectors and even the characteristics of the detectors of the matrix are not uniform, it is possible to use these cameras for Non- Destructive Evaluation (NDE). The main idea is to use the video output data and associate to such devices recording and real time systems with adapted processing methods, in order to set out a very cheap NDE system. We present, in this framework, some processing methods based on the estimation of thermophysical parameters variations around a nominal value by an asymptotic gradient development. Theoretical arguments will illustrate this purpose and several examples in various industrial domains will be shown: estimation of thickness variations of a PVC plate; estimation of density variation of ceramic plates; estimation of thermal conductivity variation of textile layers.

  10. Nondestructive Evaluation of Submicron Delaminations at Polymer/Metal Interface in Flex Circuits

    NASA Astrophysics Data System (ADS)

    Nalladega, Vijayaraghava; Sathish, Shamachary; Brar, Amarjit S.

    2006-03-01

    The dimensions of the defects in micro-electronic components have reached the resolution limit of many traditional quality control instruments. As the sizes of the components are reaching a few hundred microns, the life of the components will be limited by defects of submicron dimensions. In this regard, there is a need for development of new NDE techniques to detect submicron defects. In this paper we examine the use of combined Atomic Force Microscopy (AFM) and Ultrasonic Force Microscopy (UFM) to evaluate submicron and nanometer size delaminations at the polymer-metal interface of a flex circuit. Surface topography images obtained using atomic force microscopy is compared with ultrasonic force microscopy images obtained on the same region of the flex circuits. The contrast in the UFM images show detailed features of delaminations present at the polymer/metal interface. It also reveals the microstructure of copper sandwiched between two polymer layers. Experiments were performed to image the growth and evolution of delaminations while a constant current is passed through the copper conductor. Results of microstructure of copper through a polymer layer and growth of delaminations are presented. The role of the two microscopes as a quality-control tool in micro-electronics and computer industries is discussed.

  11. Non-destructive evaluation of laboratory scale hydraulic fracturing using acoustic emission

    NASA Astrophysics Data System (ADS)

    Hampton, Jesse Clay

    The primary objective of this research is to develop techniques to characterize hydraulic fractures and fracturing processes using acoustic emission monitoring based on laboratory scale hydraulic fracturing experiments. Individual microcrack AE source characterization is performed to understand the failure mechanisms associated with small failures along pre-existing discontinuities and grain boundaries. Individual microcrack analysis methods include moment tensor inversion techniques to elucidate the mode of failure, crack slip and crack normal direction vectors, and relative volumetric deformation of an individual microcrack. Differentiation between individual microcrack analysis and AE cloud based techniques is studied in efforts to refine discrete fracture network (DFN) creation and regional damage quantification of densely fractured media. Regional damage estimations from combinations of individual microcrack analyses and AE cloud density plotting are used to investigate the usefulness of weighting cloud based AE analysis techniques with microcrack source data. Two granite types were used in several sample configurations including multi-block systems. Laboratory hydraulic fracturing was performed with sample sizes ranging from 15 x 15 x 25 cm3 to 30 x 30 x 25 cm 3 in both unconfined and true-triaxially confined stress states using different types of materials. Hydraulic fracture testing in rock block systems containing a large natural fracture was investigated in terms of AE response throughout fracture interactions. Investigations of differing scale analyses showed the usefulness of individual microcrack characterization as well as DFN and cloud based techniques. Individual microcrack characterization weighting cloud based techniques correlated well with post-test damage evaluations.

  12. 3D Ultrasonic Non-destructive Evaluation of Spot Welds Using an Enhanced Total Focusing Method

    NASA Astrophysics Data System (ADS)

    Jasiuniene, Elena; Samaitis, Vykintas; Mazeika, Liudas; Sanderson, Ruth

    2015-02-01

    Spot welds are used to join sheets of metals in the automotive industry. When spot weld quality is evaluated using conventional ultrasonic manual pulse-echo method, the reliability of the inspection is affected by selection of the probe diameter and the positioning of the probe in the weld center. The application of a 2D matrix array is a potential solution to the aforementioned problems. The objective of this work was to develop a signal processing algorithm to reconstruct the 3D spot weld volume showing the size of the nugget and the defects in it. In order to achieve this, the conventional total focusing method was enhanced by taking into account the directivities of the single elements of the array and the divergence of the ultrasonic beam due to the propagation distance. Enhancements enabled a reduction in the background noise and uniform sensitivity at different depths to be obtained. The proposed algorithm was verified using a finite element model of ultrasonic wave propagation simulating three common spot weld conditions: a good weld, an undersized weld, and a weld containing a pore. The investigations have demonstrated that proposed method enables the determination of the size of the nugget and detection of discontinuities.

  13. Nondestructive Evaluation of Friction Stir-Welded Aluminum Alloy to Coated Steel Sheet Lap Joint

    NASA Astrophysics Data System (ADS)

    Das, H.; Kumar, A.; Rajkumar, K. V.; Saravanan, T.; Jayakumar, T.; Pal, Tapan Kumar

    2015-11-01

    Dissimilar lap joints of aluminum sheet (AA 6061) of 2 mm thickness and zinc-coated steel sheet of 1 mm thickness were produced by friction stir welding with different combinations of rotational speed and travel speed. Ultrasonic C- and B-scanning, and radiography have been used in a complementary manner for detection of volumetric (cavity and flash) and planar (de bond) defects as the defects are in micron level. Advanced ultrasonic C-scanning did not provide any idea about the defects, whereas B-scanning cross-sectional image showed an exclusive overview of the micron-level defects. A digital x-ray radiography methodology is proposed for quality assessment of the dissimilar welds which provide three-fold increase in signal-to-noise ratio with improved defect detection sensitivity. The present study clearly shows that the weld tool rotational speed and travel speed have a decisive role on the quality of the joints obtained by the friction stir welding process. The suitability of the proposed NDE techniques to evaluate the joint integrity of dissimilar FSW joints is thus established.

  14. Nondestructive evaluation of residual stress in short-fiber reinforced plastics by x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Tanaka, Keisuke; Tokoro, Syouhei; Akiniwa, Yoshiaki; Egami, Noboru

    2014-06-01

    The X-ray diffraction method is used to measure the residual stress in injection-molded plates of short-fiber reinforced plastics (SFRP) made of crystalline thermoplastics, polyphenylene sulphide (PPS), reinforced by carbon fibers with 30 mass%. Based on the orientation of carbon fibers, injection molded plates can be modeled as three-layered lamella where the core layer is sandwiched by skin layers. The stress in the matrix in the skin layer was measured using Cr-Kα radiation with the sin2Ψ method. Since the X-ray penetration depth is shallow, the state of stresses measured by X-rays in FRP can be assumed to be plane stress. The X-ray measurement of stress in carbon fibers was not possible because of high texture. A new method was proposed to evaluate the macrostress in SFRP from the measurement of the matrix stress. According to micromechanics analysis of SFRP, the matrix stresses in the fiber direction, σ1m, and perpendicular to the fiber direction, σ2m, and shear stress τ12m can be expressed as the functions of the applied (macro-) stresses, σ1A, σ2A , τ12A as follows: σ1m = α11σ1A +α12σ2A, σ2m = α21σ1A + α22σ2A, τ12m = α66τ12A, where α11 ,α12, α21, α22, α66 are stress-partitioning coefficients. Using skin-layer strips cut parallel, perpendicular and 45° to the molding direction, the stress in the matrix was measured under the uniaxial applied stress and the stress-partitioning coefficients of the above equations were determined. Once these relations are established, the macrostress in SFRP can be determined from the measurements of the matrix stresses by X-rays.

  15. Autonomous corrosion detection in gas pipelines: a hybrid-fuzzy classifier approach using ultrasonic nondestructive evaluation protocols.

    PubMed

    Qidwai, Uvais A

    2009-12-01

    In this paper, a customized classifier is presented for the industry-practiced nondestructive evaluation (NDE) protocols using a hybrid-fuzzy inference system (FIS) to classify the corrosion and distinguish it from the geometric defects or normal/healthy state of the steel pipes used in the gas/petroleum industry. The presented system is hybrid in the sense that it utilizes both soft computing through fuzzy set theory, as well as conventional parametric modeling through H(infinity) optimization methods. Due to significant uncertainty in the power spectral density of the noise in ultrasonic NDE procedures, the use of optimal H(2) estimators for defect characterization is not so accurate. A more appropriate criterion is the H(infinity) norm of the estimation error spectrum which is based on minimization of the magnitude of this spectrum and hence produces more robust estimates. A hybrid feature set is developed in this work that corresponds to a) geometric features extracted directly from the raw ultrasonic A-scan data (which are the ultrasonic echo pulses in 1-Dtraveling inside the metal perpendicular to its 2 surfaces) and b) mapped features from the impulse response of the estimated model of the defect waveform under study. An experimental strategy is first outlined, through which the necessary data are collected as A-scans. Then, using the H(infinity) estimation approach, a parametric transfer function is obtained for each pulse. In this respect, each A-scan is treated as output from a defining function when a pure/healthy metal's A-scan is used as its input. Three defining states are considered in the paper; healthy, corroded, and defective, where the defective class represents metal with artificial or other defects. The necessary features are then calculated and are then supplied to the fuzzy inference system as input to be used in the classification. The resulting system has shown excellent corrosion classification with very low misclassification and false alarm rates. PMID:20040402

  16. Voluntary Consensus Organization Standards for Nondestructive Evaluation of Thin-Walled Metallic Liners and Composite Overwraps in Composite Overwrapped Pressure Vessels

    NASA Technical Reports Server (NTRS)

    Waller, Jess; Saulsberry, Regor

    2012-01-01

    NASA fracture control requirements outlined in NASA-STD-5009 and NASA-STD-5014 are predicated on the availability and use of sensitive nondestructive evaluation (NDE) methods that can detect and monitor defects, thereby providing data that can be used to predict failure or reduce the risk of failure in fracture critical components. However, in the case of composite materials and components, including composite overwrapped pressure vessels (COPVs), the effect of defects is poorly understood, the NDE methods used to evaluate locate and size defects are typically at lower technical readiness level than analogous NDE methods used for metals, and demonstration studies to verify the probability of detection (POD) are generally lacking or unavailable. These factors together make failure prediction of fracture critical composite materials and components based on size, quantity, or orientation of defects nearly impossible. Also, when inspecting metal liners in as-manufactured COPVs, sensitivity is lost and only the inner surface of the liner is accessible. Also, NDE of COPVs as applied during manufacturing varies significantly from manufacturer to manufacturer and has not yet been standardized. Although requirements exist to perform NDE immediately after manufacturing to establish initial integrity of the parts, procedural detail for NDE of composites is still nonexistent or under development. For example, in practice, only a visual inspection of COPVs is performed during manufacturing and service, leaving in question whether defects of concern, for example, bridging, overwrap winding anomalies, impact damage below visible threshold, out-of-family strain growth, and liner buckling have been adequately detected and monitored. To address these shortcomings, in 2005 the NASA Nondestructive Evaluation Working Group (NNWG) began funding work to develop and adopt standards for nondestructive evaluation of aerospace composites in collaboration with the American Society for Testing and Materials (ASTM) Committee E07 on Nondestructive Testing. Similarly, in 2006 the NASA Engineering and Safety Center (NESC) recommended that nondestructive evaluation methods that can predict composite failure in COPVs should be developed and verified, and integrated into the damage control plan for these vessels

  17. A quantitative method for evaluating numerical simulation accuracy of time-transient Lamb wave propagation with its applications to selecting appropriate element size and time step.

    PubMed

    Wan, Xiang; Xu, Guanghua; Zhang, Qing; Tse, Peter W; Tan, Haihui

    2016-01-01

    Lamb wave technique has been widely used in non-destructive evaluation (NDE) and structural health monitoring (SHM). However, due to the multi-mode characteristics and dispersive nature, Lamb wave propagation behavior is much more complex than that of bulk waves. Numerous numerical simulations on Lamb wave propagation have been conducted to study its physical principles. However, few quantitative studies on evaluating the accuracy of these numerical simulations were reported. In this paper, a method based on cross correlation analysis for quantitatively evaluating the simulation accuracy of time-transient Lamb waves propagation is proposed. Two kinds of error, affecting the position and shape accuracies are firstly identified. Consequently, two quantitative indices, i.e., the GVE (group velocity error) and MACCC (maximum absolute value of cross correlation coefficient) derived from cross correlation analysis between a simulated signal and a reference waveform, are proposed to assess the position and shape errors of the simulated signal. In this way, the simulation accuracy on the position and shape is quantitatively evaluated. In order to apply this proposed method to select appropriate element size and time step, a specialized 2D-FEM program combined with the proposed method is developed. Then, the proper element size considering different element types and time step considering different time integration schemes are selected. These results proved that the proposed method is feasible and effective, and can be used as an efficient tool for quantitatively evaluating and verifying the simulation accuracy of time-transient Lamb wave propagation. PMID:26315506

  18. Direct, non-destructive, and rapid evaluation of developmental cotton fibers by ATR FT-IR spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chemical, compositional, and structural differences within the fibers at different growth stages have been investigated considerably through a number of methodologies. Due to its direct, non-destructive, and rapid attribute, this study reports the utilization of attenuated total reflection Fourier t...

  19. An anthropomorphic phantom for quantitative evaluation of breast MRI

    PubMed Central

    Freed, Melanie; de Zwart, Jacco A.; Loud, Jennifer T.; El Khouli, Riham H.; Myers, Kyle J.; Greene, Mark H.; Duyn, Jeff H.; Badano, Aldo

    2011-01-01

    Purpose: In this study, the authors aim to develop a physical, tissue-mimicking phantom for quantitative evaluation of breast MRI protocols. The objective of this phantom is to address the need for improved standardization in breast MRI and provide a platform for evaluating the influence of image protocol parameters on lesion detection and discrimination. Quantitative comparisons between patient and phantom image properties are presented. Methods: The phantom is constructed using a mixture of lard and egg whites, resulting in a random structure with separate adipose- and glandular-mimicking components. T1 and T2 relaxation times of the lard and egg components of the phantom were estimated at 1.5 T from inversion recovery and spin-echo scans, respectively, using maximum-likelihood methods. The image structure was examined quantitatively by calculating and comparing spatial covariance matrices of phantom and patient images. A static, enhancing lesion was introduced by creating a hollow mold with stereolithography and filling it with a gadolinium-doped water solution. Results: Measured phantom relaxation values fall within 2 standard errors of human values from the literature and are reasonably stable over 9 months of testing. Comparison of the covariance matrices of phantom and patient data demonstrates that the phantom and patient data have similar image structure. Their covariance matrices are the same to within error bars in the anterior-posterior direction and to within about two error bars in the right-left direction. The signal from the phantom’s adipose-mimicking material can be suppressed using active fat-suppression protocols. A static, enhancing lesion can also be included with the ability to change morphology and contrast agent concentration. Conclusions: The authors have constructed a phantom and demonstrated its ability to mimic human breast images in terms of key physical properties that are relevant to breast MRI. This phantom provides a platform for the optimization and standardization of breast MRI imaging protocols for lesion detection and characterization. PMID:21452712

  20. A System of Quantitative Evaluation of the Weld Bead

    NASA Astrophysics Data System (ADS)

    Terada, Kenji; Yamato, Kazuhiro; Miyahara, Hiroyuki; Ohta, Shohei

    The welding is the important basic technology of joining two materials together. The quality is influenced in the skill of the personwho carried out the welding. Therefore, the welding license examination and the welding skill contest are carried out in each prefecture. The judge checks the height and width of the welding bead by using caliper whether it has satisfied the standard value. In addition, the beauty is evaluated and the score is decided by the visual observation. Therefore if the judge is different, it is different in the decision for the same weld bead. In this paper, the authors propose a system of quantitative evaluation of the welding bead by using three-dimensional data obtained by the slit light projecting method.

  1. Structural Anomalies Detected in Ceramic Matrix Composites Using Combined Nondestructive Evaluation and Finite Element Analysis (NDE and FEA)

    NASA Technical Reports Server (NTRS)

    Abdul-Aziz, Ali; Baaklini, George Y.; Bhatt, Ramakrishna T.

    2003-01-01

    Most reverse engineering approaches involve imaging or digitizing an object and then creating a computerized reconstruction that can be integrated, in three dimensions, into a particular design environment. The rapid prototyping technique builds high-quality physical prototypes directly from computer-aided design files. This fundamental technique for interpreting and interacting with large data sets is being used here via Velocity2 (an integrated image-processing software, ref. 1) using computed tomography (CT) data to produce a prototype three-dimensional test specimen model for analyses. A study at the NASA Glenn Research Center proposes to use these capabilities to conduct a combined nondestructive evaluation (NDE) and finite element analysis (FEA) to screen pretest and posttest structural anomalies in structural components. A tensile specimen made of silicon nitrite (Si3N4) ceramic matrix composite was considered to evaluate structural durability and deformity. Ceramic matrix composites are being sought as candidate materials to replace nickel-base superalloys for turbine engine applications. They have the unique characteristics of being able to withstand higher operating temperatures and harsh combustion environments. In addition, their low densities relative to metals help reduce component mass (ref. 2). Detailed three-dimensional volume rendering of the tensile test specimen was successfully carried out with Velocity2 (ref. 1) using two-dimensional images that were generated via computed tomography. Subsequent, three-dimensional finite element analyses were performed, and the results obtained were compared with those predicted by NDE-based calculations and experimental tests. It was shown that Velocity2 software can be used to render a three-dimensional object from a series of CT scan images with a minimum level of complexity. The analytical results (ref. 3) show that the high-stress regions correlated well with the damage sites identified by the CT scans and the experimental data. Furthermore, modeling of the voids collected via NDE offered an analytical advantage that resulted in more accurate assessments of the material s structural strength. The top figure shows a CT scan image of the specimen test section illustrating various hidden structural entities in the material and an optical image of the test specimen considered in this study. The bottom figure represents the stress response predicted from the finite element analyses (ref .3 ) for a selected CT slice where it clearly illustrates the correspondence of the high stress risers due to voids in the material with those predicted by the NDE. This study is continuing, and efforts are concentrated on improving the modeling capabilities to imitate the structural anomalies as detected.

  2. Best practices for evaluating the capability of nondestructive evaluation (NDE) and structural health monitoring (SHM) techniques for damage characterization

    NASA Astrophysics Data System (ADS)

    Aldrin, John C.; Annis, Charles; Sabbagh, Harold A.; Lindgren, Eric A.

    2016-02-01

    A comprehensive approach to NDE and SHM characterization error (CE) evaluation is presented that follows the framework of the `ahat-versus-a' regression analysis for POD assessment. Characterization capability evaluation is typically more complex with respect to current POD evaluations and thus requires engineering and statistical expertise in the model-building process to ensure all key effects and interactions are addressed. Justifying the statistical model choice with underlying assumptions is key. Several sizing case studies are presented with detailed evaluations of the most appropriate statistical model for each data set. The use of a model-assisted approach is introduced to help assess the reliability of NDE and SHM characterization capability under a wide range of part, environmental and damage conditions. Best practices of using models are presented for both an eddy current NDE sizing and vibration-based SHM case studies. The results of these studies highlight the general protocol feasibility, emphasize the importance of evaluating key application characteristics prior to the study, and demonstrate an approach to quantify the role of varying SHM sensor durability and environmental conditions on characterization performance.

  3. Nondestructive test of regenerative chambers

    NASA Technical Reports Server (NTRS)

    Malone, G. A.; Stauffis, R.; Wood, R.

    1972-01-01

    Flat panels simulating internally cooled regenerative thrust chamber walls were fabricated by electroforming, brazing and diffusion bonding to evaluate the feasibility of nondestructive evaluation techniques to detect bonds of various strength integrities. Ultrasonics, holography, and acoustic emission were investigated and found to yield useful and informative data regarding the presence of bond defects in these structures.

  4. Nondestructive quantitative mapping of impurities and point defects in thin films: Ga and V{sub Zn} in ZnO:Ga

    SciTech Connect

    Look, David C.; Leedy, Kevin D.; Agresta, Donald L.

    2014-06-16

    Ga-doped ZnO (GZO) films grown by pulsed-laser deposition on quartz and other lattice-mismatched substrates can routinely attain resistivities of 2 × 10{sup −4} Ω·cm and thus compete with Sn-doped In{sub 2}O{sub 3} (ITO) in large-area transparent-electrode applications. Nondestructive, high-resolution (1-mm) maps of thickness d, concentration n, and mobility μ on such films can be obtained automatically from commercial spectroscopic ellipsometers. From n and μ, degenerate-electron scattering theory yields donor N{sub D} and acceptor N{sub A} concentrations at each point. Finally, N{sub D} and N{sub A} can be identified as [Ga] and [V{sub Zn}], respectively, demonstrating high-density mapping of impurities and point defects in a semiconductor thin film.

  5. Non-destructive flavour evaluation of red onion (Allium cepa L.) ecotypes: an electronic-nose-based approach.

    PubMed

    Russo, Mariateresa; di Sanzo, Rosa; Cefaly, Vittoria; Carabetta, Sonia; Serra, Demetrio; Fuda, Salvatore

    2013-11-15

    This work reports preliminary results on the potential of a metal oxide sensor (MOS)-based electronic nose, as a non-destructive method to discriminate three "Tropea Red Onion" PGI ecotypes (TrT, TrMC and TrA) from each other and the common red onion (RO), which is usually used to counterfeit. The signals from the sensor array were processed using a canonical discriminant function analysis (DFA) pattern recognition technique. The DFA on onion samples showed a clear separation among the four onion groups with an overall correct classification rate (CR) of 97.5%. Onion flavour is closely linked to pungency and thus to the pyruvic acid content. The e-nose analysis results are in good agreement with pyruvic acid analysis. This work demonstrated that artificial olfactory systems have potential for use as an innovative, rapid and specific non-destructive technique, and may provide a method to protect food products against counterfeiting. PMID:23790864

  6. Quantitative immunochemical evaluation of fish metallothionein upon exposure to cadmium.

    PubMed

    Yudkovski, Yana; Rogowska-Wrzesinska, Adelina; Yankelevich, Irena; Shefer, Edna; Herut, Barak; Tom, Moshe

    2008-06-01

    Efficient implementation of an environmental biomarker requires multi-annual comparability over a wide geographical range. The present study improved the comparability of a quantitative competitive metallothionein (MT) enzyme-linked-immuno-sorbent-assay (ELISA) in the sentinel fish Lithognathus mormyrus by introducing to the assay recombinant MT and beta-actin standards. Commercial antibodies for cod MT and mammalian actin were implemented. In addition, a sensitive anti L. mormyrus MT antibody was produced, adequate only for solid phase immunochemical assays. Cadmium was applied to the fish through injection and feeding to serve as a testing platform of the ELISA. The results demonstrated high potential protective capacity of the liver against toxic levels of transition metals through increasing MT levels. MT transcript levels were evaluated also from fish sampled at polluted and relatively clean natural sites, indicating applicability of MT as biomarker of exposure to a multi-factorial pollution, in comparison to its low revealed sensitivity to controlled cadmium exposure. PMID:18342364

  7. Quantitative evaluation of macrophage phagocytosing capacity by a fluorometric assay.

    PubMed

    Miliukiene, Vale; Biziuleviciene, Gene; Pilinkiene, Audrone

    2003-01-01

    This paper reviews sensitive and simple quantitative evaluation of macrophage phagocytosing capacity by applying fluoresecin-labeled Sacharomyces cerevisiae cells. Yeast cells were conjugated with fluoresceinisothiocyanate (FITC) and used as fluorescent particles. A time course analysis within this method showed that phagocytosis of yeast cells was temperature dependent and that the number of that ones ingested by macrophages increased rapidly during the initial 60 min of incubation at 37 degrees C. Free fluorescent cells can be effectively removed by aspiration from the well. Furthermore, yeast cells required preopsonization with serum to achieve optimal uptake of the cells. The uptake of nonopsonized yeast cells by macrophages was significantly lower than that of opsonized cells (P < 0.05). We propose that about 50% of mouse macrophages can carry functionally active FcR responsible for phagocytosis. PMID:14711038

  8. Quantitative Evaluation and Selection of Reference Genes for Quantitative RT-PCR in Mouse Acute Pancreatitis

    PubMed Central

    Yan, Zhaoping; Gao, Jinhang; Lv, Xiuhe; Yang, Wenjuan; Wen, Shilei; Tong, Huan; Tang, Chengwei

    2016-01-01

    The analysis of differences in gene expression is dependent on normalization using reference genes. However, the expression of many of these reference genes, as evaluated by quantitative RT-PCR, is upregulated in acute pancreatitis, so they cannot be used as the standard for gene expression in this condition. For this reason, we sought to identify a stable reference gene, or a suitable combination, for expression analysis in acute pancreatitis. The expression stability of 10 reference genes (ACTB, GAPDH, 18sRNA, TUBB, B2M, HPRT1, UBC, YWHAZ, EF-1α, and RPL-13A) was analyzed using geNorm, NormFinder, and BestKeeper software and evaluated according to variations in the raw Ct values. These reference genes were evaluated using a comprehensive method, which ranked the expression stability of these genes as follows (from most stable to least stable): RPL-13A, YWHAZ > HPRT1 > GAPDH > UBC > EF-1α > 18sRNA > B2M > TUBB > ACTB. RPL-13A was the most suitable reference gene, and the combination of RPL-13A and YWHAZ was the most stable group of reference genes in our experiments. The expression levels of ACTB, TUBB, and B2M were found to be significantly upregulated during acute pancreatitis, whereas the expression level of 18sRNA was downregulated. Thus, we recommend the use of RPL-13A or a combination of RPL-13A and YWHAZ for normalization in qRT-PCR analyses of gene expression in mouse models of acute pancreatitis. PMID:27069927

  9. Comparison of methods for quantitative evaluation of endoscopic distortion

    NASA Astrophysics Data System (ADS)

    Wang, Quanzeng; Castro, Kurt; Desai, Viraj N.; Cheng, Wei-Chung; Pfefer, Joshua

    2015-03-01

    Endoscopy is a well-established paradigm in medical imaging, and emerging endoscopic technologies such as high resolution, capsule and disposable endoscopes promise significant improvements in effectiveness, as well as patient safety and acceptance of endoscopy. However, the field lacks practical standardized test methods to evaluate key optical performance characteristics (OPCs), in particular the geometric distortion caused by fisheye lens effects in clinical endoscopic systems. As a result, it has been difficult to evaluate an endoscope's image quality or assess its changes over time. The goal of this work was to identify optimal techniques for objective, quantitative characterization of distortion that are effective and not burdensome. Specifically, distortion measurements from a commercially available distortion evaluation/correction software package were compared with a custom algorithm based on a local magnification (ML) approach. Measurements were performed using a clinical gastroscope to image square grid targets. Recorded images were analyzed with the ML approach and the commercial software where the results were used to obtain corrected images. Corrected images based on the ML approach and the software were compared. The study showed that the ML method could assess distortion patterns more accurately than the commercial software. Overall, the development of standardized test methods for characterizing distortion and other OPCs will facilitate development, clinical translation, manufacturing quality and assurance of performance during clinical use of endoscopic technologies.

  10. A quantitative evaluation of the public response to climate engineering

    NASA Astrophysics Data System (ADS)

    Wright, Malcolm J.; Teagle, Damon A. H.; Feetham, Pamela M.

    2014-02-01

    Atmospheric greenhouse gas concentrations continue to increase, with CO2 passing 400 parts per million in May 2013. To avoid severe climate change and the attendant economic and social dislocation, existing energy efficiency and emissions control initiatives may need support from some form of climate engineering. As climate engineering will be controversial, there is a pressing need to inform the public and understand their concerns before policy decisions are taken. So far, engagement has been exploratory, small-scale or technique-specific. We depart from past research to draw on the associative methods used by corporations to evaluate brands. A systematic, quantitative and comparative approach for evaluating public reaction to climate engineering is developed. Its application reveals that the overall public evaluation of climate engineering is negative. Where there are positive associations they favour carbon dioxide removal (CDR) over solar radiation management (SRM) techniques. Therefore, as SRM techniques become more widely known they are more likely to elicit negative reactions. Two climate engineering techniques, enhanced weathering and cloud brightening, have indistinct concept images and so are less likely to draw public attention than other CDR or SRM techniques.

  11. [Clinical evaluation of a novel HBsAg quantitative assay].

    PubMed

    Takagi, Kazumi; Tanaka, Yasuhito; Naganuma, Hatsue; Hiramatsu, Kumiko; Iida, Takayasu; Takasaka, Yoshimitsu; Mizokami, Masashi

    2007-07-01

    The clinical implication of the hepatitis B surface antigen (HBsAg) concentrations in HBV-infected individuals remains unclear. The aim of this study was to evaluate a novel fully automated Chemiluminescence Enzyme Immunoassay (Sysmex HBsAg quantitative assay) by comparative measurements of the reference serum samples versus two independent commercial assays (Lumipulse f or Architect HBsAg QT). Furthermore, clinical usefulness was assessed for monitoring of the serum HBsAg levels during antiviral therapy. A dilution test using 5 reference-serum samples showed linear correlation curve in range from 0.03 to 2,360 IU/ml. The HBsAg was measured in total of 400 serum samples and 99.8% had consistent results between Sysmex and Lumipulse f. Additionally, a positive linear correlation was observed between Sysmex and Architect. To compare the Architect and Sysmex, both methods were applied to quantify the HBsAg in serum samples with different HBV genotypes/subgenotypes, as well as in serum contained HBV vaccine escape mutants (126S, 145R). Correlation between the methods was observed in results for escape mutants and common genotypes (A, B, C) in Japan. Observed during lamivudine therapy, an increase in HBsAg and HBV DNA concentrations preceded the aminotransferase (ALT) elevation associated with drug-resistant HBV variant emergence (breakthrough hepatitis). In conclusion, reliability of the Sysmex HBsAg quantitative assay was confirmed for all HBV genetic variants common in Japan. Monitoring of serum HBsAg concentrations in addition to HBV DNA quantification, is helpful in evaluation of the response to lamivudine treatment and diagnosis of the breakthrough hepatitis. PMID:17718057

  12. Quantitative genetic activity graphical profiles for use in chemical evaluation

    SciTech Connect

    Waters, M.D.; Stack, H.F.; Garrett, N.E.; Jackson, M.A.

    1990-12-31

    A graphic approach, terms a Genetic Activity Profile (GAP), was developed to display a matrix of data on the genetic and related effects of selected chemical agents. The profiles provide a visual overview of the quantitative (doses) and qualitative (test results) data for each chemical. Either the lowest effective dose or highest ineffective dose is recorded for each agent and bioassay. Up to 200 different test systems are represented across the GAP. Bioassay systems are organized according to the phylogeny of the test organisms and the end points of genetic activity. The methodology for producing and evaluating genetic activity profile was developed in collaboration with the International Agency for Research on Cancer (IARC). Data on individual chemicals were compiles by IARC and by the US Environmental Protection Agency (EPA). Data are available on 343 compounds selected from volumes 1-53 of the IARC Monographs and on 115 compounds identified as Superfund Priority Substances. Software to display the GAPs on an IBM-compatible personal computer is available from the authors. Structurally similar compounds frequently display qualitatively and quantitatively similar profiles of genetic activity. Through examination of the patterns of GAPs of pairs and groups of chemicals, it is possible to make more informed decisions regarding the selection of test batteries to be used in evaluation of chemical analogs. GAPs provided useful data for development of weight-of-evidence hazard ranking schemes. Also, some knowledge of the potential genetic activity of complex environmental mixtures may be gained from an assessment of the genetic activity profiles of component chemicals. The fundamental techniques and computer programs devised for the GAP database may be used to develop similar databases in other disciplines. 36 refs., 2 figs.

  13. Evaluation of a virucidal quantitative carrier test for surface disinfectants.

    PubMed

    Rabenau, Holger F; Steinmann, Jochen; Rapp, Ingrid; Schwebke, Ingeborg; Eggers, Maren

    2014-01-01

    Surface disinfectants are part of broader preventive strategies preventing the transmission of bacteria, fungi and viruses in medical institutions. To evaluate their virucidal efficacy, these products must be tested with appropriate model viruses with different physico-chemical properties under conditions representing practical application in hospitals. The aim of this study was to evaluate a quantitative carrier assay. Furthermore, different putative model viruses like adenovirus type 5 (AdV-5) and different animal parvoviruses were evaluated with respect to their tenacity and practicability in laboratory handling. To evaluate the robustness of the method, some of the viruses were tested in parallel in different laboratories in a multi-center study. Different biocides, which are common active ingredients of surface disinfectants, were used in the test. After drying on stainless steel discs as the carrier, model viruses were exposed to different concentrations of three alcohols, peracetic acid (PAA) or glutaraldehyde (GDA), with a fixed exposure time of 5 minutes. Residual virus was determined after treatment by endpoint titration. All parvoviruses exhibited a similar stability with respect to GDA, while AdV-5 was more susceptible. For PAA, the porcine parvovirus was more sensitive than the other parvoviruses, and again, AdV-5 presented a higher susceptibility than the parvoviruses. All parvoviruses were resistant to alcohols, while AdV-5 was only stable when treated with 2-propanol. The analysis of the results of the multi-center study showed a high reproducibility of this test system. In conclusion, two viruses with different physico-chemical properties can be recommended as appropriate model viruses for the evaluation of the virucidal efficacy of surface disinfectants: AdV-5, which has a high clinical impact, and murine parvovirus (MVM) with the highest practicability among the parvoviruses tested. PMID:24475079

  14. Nuclear medicine and imaging research (instrumentation and quantitative methods of evaluation)

    SciTech Connect

    Beck, R.N.; Cooper, M.; Chen, C.T.

    1992-07-01

    This document is the annual progress report for project entitled 'Instrumentation and Quantitative Methods of Evaluation.' Progress is reported in separate sections individually abstracted and indexed for the database. Subject areas reported include theoretical studies of imaging systems and methods, hardware developments, quantitative methods of evaluation, and knowledge transfer: education in quantitative nuclear medicine imaging.

  15. Non-contact, non-destructive, quantitative probing of interfacial trap sites for charge carrier transport at semiconductor-insulator boundary

    SciTech Connect

    Choi, Wookjin; Miyakai, Tomoyo; Sakurai, Tsuneaki; Saeki, Akinori; Yokoyama, Masaaki; Seki, Shu

    2014-07-21

    The density of traps at semiconductor–insulator interfaces was successfully estimated using microwave dielectric loss spectroscopy with model thin-film organic field-effect transistors. The non-contact, non-destructive analysis technique is referred to as field-induced time-resolved microwave conductivity (FI-TRMC) at interfaces. Kinetic traces of FI-TRMC transients clearly distinguished the mobile charge carriers at the interfaces from the immobile charges trapped at defects, allowing both the mobility of charge carriers and the number density of trap sites to be determined at the semiconductor-insulator interfaces. The number density of defects at the interface between evaporated pentacene on a poly(methylmethacrylate) insulating layer was determined to be 10{sup 12 }cm{sup −2}, and the hole mobility was up to 6.5 cm{sup 2} V{sup −1} s{sup −1} after filling the defects with trapped carriers. The FI-TRMC at interfaces technique has the potential to provide rapid screening for the assessment of interfacial electronic states in a variety of semiconductor devices.

  16. Evaluating the Quantitative Capabilities of Metagenomic Analysis Software.

    PubMed

    Kerepesi, Csaba; Grolmusz, Vince

    2016-05-01

    DNA sequencing technologies are applied widely and frequently today to describe metagenomes, i.e., microbial communities in environmental or clinical samples, without the need for culturing them. These technologies usually return short (100-300 base-pairs long) DNA reads, and these reads are processed by metagenomic analysis software that assign phylogenetic composition-information to the dataset. Here we evaluate three metagenomic analysis software (AmphoraNet-a webserver implementation of AMPHORA2-, MG-RAST, and MEGAN5) for their capabilities of assigning quantitative phylogenetic information for the data, describing the frequency of appearance of the microorganisms of the same taxa in the sample. The difficulties of the task arise from the fact that longer genomes produce more reads from the same organism than shorter genomes, and some software assign higher frequencies to species with longer genomes than to those with shorter ones. This phenomenon is called the "genome length bias." Dozens of complex artificial metagenome benchmarks can be found in the literature. Because of the complexity of those benchmarks, it is usually difficult to judge the resistance of a metagenomic software to this "genome length bias." Therefore, we have made a simple benchmark for the evaluation of the "taxon-counting" in a metagenomic sample: we have taken the same number of copies of three full bacterial genomes of different lengths, break them up randomly to short reads of average length of 150 bp, and mixed the reads, creating our simple benchmark. Because of its simplicity, the benchmark is not supposed to serve as a mock metagenome, but if a software fails on that simple task, it will surely fail on most real metagenomes. We applied three software for the benchmark. The ideal quantitative solution would assign the same proportion to the three bacterial taxa. We have found that AMPHORA2/AmphoraNet gave the most accurate results and the other two software were under-performers: they counted quite reliably each short read to their respective taxon, producing the typical genome length bias. The benchmark dataset is available at http://pitgroup.org/static/3RandomGenome-100kavg150bps.fna . PMID:26831696

  17. Current and future developments in civil aircraft non-destructive evaluation from an operator's point of view

    NASA Technical Reports Server (NTRS)

    Register, Jeff

    1992-01-01

    In June, 1988, the first International Conference on aging aircraft was held to address nondestructive tests (NDT) of aging aircraft and other issues. From this meeting, a research program was initiated and funded by the FAA. As a result of this program, a lot of work has been done to study current NDT practices in the aviation industry and secondly, to research and develop new NDT methods to improve the reliability and efficiency of in-service inspection of aircraft structures and powerplants. The following is an overview of the current and future developments in civil aircraft NDT, as viewed by an air carrier and the concerns for NDT in the future.

  18. Infrared image processing devoted to thermal non-contact characterization-Applications to Non-Destructive Evaluation, Microfluidics and 2D source term distribution for multispectral tomography

    NASA Astrophysics Data System (ADS)

    Batsale, Jean-Christophe; Pradere, Christophe

    2015-11-01

    The cost of IR cameras is more and more decreasing. Beyond the preliminary calibration step and the global instrumentation, the infrared image processing is then one of the key step for achieving in very broad domains. Generally the IR images are coming from the transient temperature field related to the emission of a black surface in response to an external or internal heating (active IR thermography). The first applications were devoted to the so called thermal Non-Destructive Evaluation methods by considering a thin sample and 1D transient heat diffusion through the sample (transverse diffusion). With simplified assumptions related to the transverse diffusion, the in-plane diffusion and transport phenomena can be also considered. A general equation can be applied in order to balance the heat transfer at the pixel scale or between groups of pixels in order to estimate several fields of thermophysical properties (heterogeneous field of in-plane diffusivity, flow distributions, source terms). There is a lot of possible strategies to process the space and time distributed big amount of data (previous integral transformation of the images, compression, elimination of the non useful areas...), generally based on the necessity to analyse the derivative versus space and time of the temperature field. Several illustrative examples related to the Non-Destructive Evaluation of heterogeneous solids, the thermal characterization of chemical reactions in microfluidic channels and the design of systems for multispectral tomography, will be presented.

  19. A first evaluation of the usefulness of feathers of nestling predatory birds for non-destructive biomonitoring of persistent organic pollutants.

    PubMed

    Eulaers, Igor; Covaci, Adrian; Herzke, Dorte; Eens, Marcel; Sonne, Christian; Moum, Truls; Schnug, Lisbeth; Hanssen, Sveinn Are; Johnsen, Trond Vidar; Bustnes, Jan Ove; Jaspers, Veerle L B

    2011-04-01

    In previous studies, feathers of adult predatory birds have been evaluated as valid non-destructive biomonitor matrices for persistent organic pollutants (POPs). In this study, we assessed for the first time the usefulness of nestling raptor feathers for non-destructive biomonitoring of POPs. For this purpose, we collected body feathers and blood of nestlings from three avian top predators from northern Norway: northern goshawks (Accipiter gentilis), white-tailed eagles (Haliaeetus albicilla) and golden eagles (Aquila chrysaetos). We were able to detect a broad spectrum of legacy POPs in the nestling feathers of all three species (Σ PCBs: 6.78-140ng g(-1); DDE: 3.15-145ng g(-1); Σ PBDEs: 0.538-7.56ng g(-1)). However, these concentrations were lower compared to other studies on raptor species, probably due to the aspect of monitoring of nestlings instead of adults. Besides their analytical suitability, nestling feathers also appear to be biologically informative: concentrations of most POPs in nestling feathers showed strong and significant correlations with blood plasma concentrations in all species (p<0.050; 0.775non-destructive biomonitoring strategy for POPs in their ecosystems. PMID:21256594

  20. Quantitative evaluation of intracellular metabolite extraction techniques for yeast metabolomics.

    PubMed

    Canelas, André B; ten Pierick, Angela; Ras, Cor; Seifar, Reza M; van Dam, Jan C; van Gulik, Walter M; Heijnen, Joseph J

    2009-09-01

    Accurate determination of intracellular metabolite levels requires well-validated procedures for sampling and sample treatment. Several methods exist for metabolite extraction, but the literature is contradictory regarding the adequacy and performance of each technique. Using a strictly quantitative approach, we have re-evaluated five methods (hot water, HW; boiling ethanol, BE; chloroform-methanol, CM; freezing-thawing in methanol, FTM; acidic acetonitrile-methanol, AANM) for the extraction of 44 intracellular metabolites (phosphorylated intermediates, amino acids, organic acids, nucleotides) from S. cerevisiae cells. Two culture modes were investigated (batch and chemostat) to check for growth condition dependency, and three targeted platforms were employed (two LC-MS and one GC/MS) to exclude analytical bias. Additionally, for the determination of metabolite recoveries, we applied a novel approach based on addition of (13)C-labeled internal standards at different stages of sample processing. We found that the choice of extraction method can drastically affect measured metabolite levels, to an extent that for some metabolites even the direction of changes between growth conditions can be inverted. The best performances, in terms of efficacy and metabolite recoveries, were achieved with BE and CM, which yielded nearly identical levels for the metabolites analyzed. According to our results, AANM performs poorly in yeast and FTM cannot be considered adequate as an extraction method, as it does not ensure inactivation of enzymatic activity. PMID:19653633

  1. Quantitative evaluation of photoplethysmographic artifact reduction for pulse oximetry

    NASA Astrophysics Data System (ADS)

    Hayes, Matthew J.; Smith, Peter R.

    1999-01-01

    Motion artefact corruption of pulse oximeter output, causing both measurement inaccuracies and false alarm conditions, is a primary restriction in the current clinical practice and future applications of this useful technique. Artefact reduction in photoplethysmography (PPG), and therefore by application in pulse oximetry, is demonstrated using a novel non-linear methodology recently proposed by the authors. The significance of these processed PPG signals for pulse oximetry measurement is discussed, with particular attention to the normalization inherent in the artefact reduction process. Quantitative experimental investigation of the performance of PPG artefact reduction is then utilized to evaluate this technology for application to pulse oximetry. While the successfully demonstrated reduction of severe artefacts may widen the applicability of all PPG technologies and decrease the occurrence of pulse oximeter false alarms, the observed reduction of slight artefacts suggests that many such effects may go unnoticed in clinical practice. The signal processing and output averaging used in most commercial oximeters can incorporate these artefact errors into the output, while masking the true PPG signal corruption. It is therefore suggested that PPG artefact reduction should be incorporated into conventional pulse oximetry measurement, even in the absence of end-user artefact problems.

  2. Quantitative evaluation of phase processing approaches in susceptibility weighted imaging

    NASA Astrophysics Data System (ADS)

    Li, Ningzhi; Wang, Wen-Tung; Sati, Pascal; Pham, Dzung L.; Butman, John A.

    2012-03-01

    Susceptibility weighted imaging (SWI) takes advantage of the local variation in susceptibility between different tissues to enable highly detailed visualization of the cerebral venous system and sensitive detection of intracranial hemorrhages. Thus, it has been increasingly used in magnetic resonance imaging studies of traumatic brain injury as well as other intracranial pathologies. In SWI, magnitude information is combined with phase information to enhance the susceptibility induced image contrast. Because of global susceptibility variations across the image, the rate of phase accumulation varies widely across the image resulting in phase wrapping artifacts that interfere with the local assessment of phase variation. Homodyne filtering is a common approach to eliminate this global phase variation. However, filter size requires careful selection in order to preserve image contrast and avoid errors resulting from residual phase wraps. An alternative approach is to apply phase unwrapping prior to high pass filtering. A suitable phase unwrapping algorithm guarantees no residual phase wraps but additional computational steps are required. In this work, we quantitatively evaluate these two phase processing approaches on both simulated and real data using different filters and cutoff frequencies. Our analysis leads to an improved understanding of the relationship between phase wraps, susceptibility effects, and acquisition parameters. Although homodyne filtering approaches are faster and more straightforward, phase unwrapping approaches perform more accurately in a wider variety of acquisition scenarios.

  3. [Quantitative evaluation of soil hyperspectra denoising with different filters].

    PubMed

    Huang, Ming-Xiang; Wang, Ke; Shi, Zhou; Gong, Jian-Hua; Li, Hong-Yi; Chen, Jie-Liang

    2009-03-01

    The noise distribution of soil hyperspectra measured by ASD FieldSpec Pro FR was described, and then the quantitative evaluation of spectral denoising with six filters was compared. From the interpretation of soil hyperspectra, the continuum removed, first-order differential and high frequency curves, the UV/VNIR (350-1 050 nm) exhibit hardly noise except the coverage of 40 nm in the beginning 350 nm. However, the SWIR (1 000-2 500 nm) shows different noise distribution. Especially, the latter half of SWIR 2(1 800-2 500 nm) showed more noise, and the intersection spectrum of three spectrometers has more noise than the neighbor spectrum. Six filters were chosen for spectral denoising. The smoothing indexes (SI), horizontal feature reservation index (HFRI) and vertical feature reservation index (VFRI) were designed for evaluating the denoising performance of these filters. The comparison of their indexes shows that WD and MA filters are the optimal choice to filter the noise, in terms of balancing the contradiction between the smoothing and feature reservation ability. Furthermore the first-order differential data of 66 denoising soil spectra by 6 filters were respectively used as the input of the same PLSR model to predict the sand content. The different prediction accuracies caused by the different filters show that compared to the feature reservation ability, the filter's smoothing ability is the principal factor to influence the accuracy. The study can benefit the spectral preprocessing and analyzing, and also provide the scientific foundation for the related spectroscopy applications. PMID:19455808

  4. Quantitative ultrasonic evaluation of mechanical properties of engineering materials

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1978-01-01

    Current progress in the application of ultrasonic techniques to nondestructive measurement of mechanical strength properties of engineering materials is reviewed. Even where conventional NDE techniques have shown that a part is free of overt defects, advanced NDE techniques should be available to confirm the material properties assumed in the part's design. There are many instances where metallic, composite, or ceramic parts may be free of critical defects while still being susceptible to failure under design loads due to inadequate or degraded mechanical strength. This must be considered in any failure prevention scheme that relies on fracture analysis. This review will discuss the availability of ultrasonic methods that can be applied to actual parts to assess their potential susceptibility to failure under design conditions.

  5. Evaluation of semi-quantitative bone scintigraphy in canine elbows.

    PubMed

    Debruyn, K; Peremans, K; Vandermeulen, E; Van Ryssen, B; Saunders, J H

    2013-06-01

    Scintigraphy is an extremely sensitive tool for the detection of early changes in bone metabolism. Sixty-eight lame dogs underwent a scintigraphic examination. For each elbow lateromedial (LM), caudomedial (CdM) flexed and caudomedial (CdM) extended scintigraphic views were obtained. Semi-quantitative analysis was performed to determine radiopharmaceutical uptake at the medial coronoid process (MCP) and at the attachment of the flexor muscles at the medial humeral epicondyle, normalised to activity registered in either the total elbow joint or the radius/ulna. MCP pathology/flexor enthesopathies were divided into simple (containing one abnormality) or complex (containing more than one abnormality) lesions. The influence of different views or normalisation procedures on sensitivity and specificity was evaluated. MCP lesions were detected on radiography, ultrasound, computed tomography, magnetic resonance imaging and/or arthroscopy in 49 elbows, with 13 simple and 36 complex lesions. Flexor enthesopathy was diagnosed in 54 elbows, with 14 simple and 40 complex lesions. In seven elbows only degenerative changes were present, whereas in 50 elbows no abnormalities could be detected. MCP lesions were best detected with the CdM extended view, whereas for flexor enthesopathy the CdM flexed view offered the best result. To detect simple lesions, the normalisation procedure to the elbow gave the best result, whereas normalisation to the radius/ulna was the best choice for complex lesions. This study suggests that semi-quantification is a valuable method in case of simple pathology, especially when MCP lesions are considered. For elbows with complex lesions, the quantification procedure is less reliable. PMID:23206663

  6. Nondestructive biomarkers in ecotoxicology.

    PubMed Central

    Fossi, M C

    1994-01-01

    The aim of this article is to attempt a concise review of the state of the art of the nondestructive biomarkers approach in vertebrates, establishing a consensus on the most useful and sensitive nondestructive biomarker techniques, and proposing research priorities for the development and validation of this promising methodology. The following topics are discussed: the advantages of the use of nondestructive strategies in biomonitoring programs and the research fields in which nondestructive biomarkers can be applied; the biological materials suitable for nondestructive biomarkers and residue analysis in vertebrates; which biomarkers lend themselves to noninvasive techniques; and the validation and implementation strategy of the nondestructive biomarker approach. Examples of applications of this methodology in the hazard assessment of endangered species are also presented. Images Figure 1. C PMID:7713034

  7. Nondestructive Test Probe

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Under the Aircraft Structural Integrity program, Langley Research Center invented a device to detect fatigue cracks in aluminum alloy plates. Krautkramer Branson obtained an exclusive license and commercialized a hand-held device, the "CrackFinder," an electromagnetic probe for nondestructive evaluation, used to scan aircraft skins for surface breaks. The technology involves an eddy current, which is an electrical current induced by an alternating magnetic field. The CrackFinder also employs an innovative self-nulling feature, where the device automatically recalibrates to zero so that each flaw detected produces a reading. Compared to conventional testing systems, the CrackFinder is affordable, small, simple to use, and needs no calibration.

  8. Light Water Reactor Sustainability (LWRS) Program – Non-Destructive Evaluation (NDE) R&D Roadmap for Determining Remaining Useful Life of Aging Cables in Nuclear Power Plants

    SciTech Connect

    Simmons, K.L.; Ramuhali, P.; Brenchley, D.L.; Coble, J.B.; Hashemian, H.M.; Konnick, R.; Ray, S.

    2012-09-01

    Executive Summary [partial] The purpose of the non-destructive evaluation (NDE) R&D Roadmap for Cables is to support the Materials Aging and Degradation (MAaD) R&D pathway. A workshop was held to gather subject matter experts to develop the NDE R&D Roadmap for Cables. The focus of the workshop was to identify the technical gaps in detecting aging cables and predicting their remaining life expectancy. The workshop was held in Knoxville, Tennessee, on July 30, 2012, at Analysis and Measurement Services Corporation (AMS) headquarters. The workshop was attended by 30 experts in materials, electrical engineering, and NDE instrumentation development from the U.S. Nuclear Regulatory Commission (NRC), U.S. Department of Energy (DOE) National Laboratories (Oak Ridge National Laboratory, Pacific Northwest National Laboratory, Argonne National Laboratory, and Idaho National Engineering Laboratory), universities, commercial NDE service vendors and cable manufacturers, and the Electric Power Research Institute (EPRI).

  9. Light Water Reactor Sustainability (LWRS) Program – Non-Destructive Evaluation (NDE) R&D Roadmap for Determining Remaining Useful Life of Aging Cables in Nuclear Power Plants

    SciTech Connect

    Simmons, Kevin L.; Ramuhalli, Pradeep; Brenchley, David L.; Coble, Jamie B.; Hashemian, Hash; Konnik, Robert; Ray, Sheila

    2012-09-14

    The purpose of the non-destructive evaluation (NDE) R&D Roadmap for Cables is to support the Materials Aging and Degradation (MAaD) R&D pathway. The focus of the workshop was to identify the technical gaps in detecting aging cables and predicting their remaining life expectancy. The workshop was held in Knoxville, Tennessee, on July 30, 2012, at Analysis and Measurement Services Corporation (AMS) headquarters. The workshop was attended by 30 experts in materials, electrical engineering, U.S. Nuclear Regulatory Commission (NRC), U.S. Department of Energy (DOE) National Laboratories (Oak Ridge National Laboratory, Pacific Northwest National Laboratory, Argonne National Laboratory, and Idaho National Engineering Laboratory), NDE instrumentation development, universities, commercial NDE services and cable manufacturers, and Electric Power Research Institute (EPRI). The motivation for the R&D roadmap comes from the need to address the aging management of in-containment cables at nuclear power plants (NPPs).

  10. Progress in evaluation and improvement in nondestructive examination reliability for inservice inspection of Light Water Reactors (LWRs) and characterize fabrication flaws in reactor pressure vessels

    SciTech Connect

    Doctor, S.R.; Bowey, R.E.; Good, M.S.; Friley, J.R.; Kurtz, R.J.; Simonen, F.A.; Taylor, T.T.; Heasler, P.G.; Andersen, E.S.; Diaz, A.A.; Greenwood, M.S.; Hockey, R.L.; Schuster, G.J.; Spanner, J.C.; Vo, T.V.

    1991-10-01

    This paper is a review of the work conducted under two programs. One (NDE Reliability Program) is a multi-year program addressing the reliability of nondestructive evaluation (NDE) for the inservice inspection (ISI) of light water reactor components. This program examines the reliability of current NDE, the effectiveness of evolving technologies, and provides assessments and recommendations to ensure that the NDE is applied at the right time, in the right place with sufficient effectiveness that defects of importance to structural integrity will be reliably detected and accurately characterized. The second program (Characterizing Fabrication Flaws in Reactor Pressure Vessels) is assembling a data base to quantify the distribution of fabrication flaws that exist in US nuclear reactor pressure vessels with respect to density, size, type, and location. These programs will be discussed as two separate sections in this report. 4 refs., 7 figs.

  11. Non-destructive evaluation of chlorophyll content in quinoa and amaranth leaves by simple and multiple regression analysis of RGB image components.

    PubMed

    Riccardi, M; Mele, G; Pulvento, C; Lavini, A; d'Andria, R; Jacobsen, S-E

    2014-06-01

    Leaf chlorophyll content provides valuable information about physiological status of plants; it is directly linked to photosynthetic potential and primary production. In vitro assessment by wet chemical extraction is the standard method for leaf chlorophyll determination. This measurement is expensive, laborious, and time consuming. Over the years alternative methods, rapid and non-destructive, have been explored. The aim of this work was to evaluate the applicability of a fast and non-invasive field method for estimation of chlorophyll content in quinoa and amaranth leaves based on RGB components analysis of digital images acquired with a standard SLR camera. Digital images of leaves from different genotypes of quinoa and amaranth were acquired directly in the field. Mean values of each RGB component were evaluated via image analysis software and correlated to leaf chlorophyll provided by standard laboratory procedure. Single and multiple regression models using RGB color components as independent variables have been tested and validated. The performance of the proposed method was compared to that of the widely used non-destructive SPAD method. Sensitivity of the best regression models for different genotypes of quinoa and amaranth was also checked. Color data acquisition of the leaves in the field with a digital camera was quick, more effective, and lower cost than SPAD. The proposed RGB models provided better correlation (highest R (2)) and prediction (lowest RMSEP) of the true value of foliar chlorophyll content and had a lower amount of noise in the whole range of chlorophyll studied compared with SPAD and other leaf image processing based models when applied to quinoa and amaranth. PMID:24442792

  12. Application of non-destructive impedance-based monitoring technique for cyclic fatigue evaluation of endodontic nickel-titanium rotary instruments.

    PubMed

    Chang, Yau-Zen; Liu, Mou-Chuan; Pai, Che-An; Lin, Chun-Li; Yen, Kuang-I

    2011-06-01

    This study investigates the application of non-destructive testing based on the impedance theory in the cyclic fatigue evaluation of endodontic Ni-Ti rotary instruments. Fifty Ni-Ti ProTaper instruments were divided into five groups (n=10 in Groups A to E). Groups A to D were subjected to cyclic fatigue within an artificial canal (Group E was the control group). The mean value of the total life limit (TLL), defined as the instrument being rotated until fracture occurred was found to be 104 s in Group A. Each rotary instrument in Groups B, C and D were rotated until the tested instruments reached 80% (84 s), 60% (62 s) and 40% (42 s) of the TLL. After fatigue testing, each rotary instrument was mounted onto a custom-developed non-destructive testing device to give the tip of the instrument a progressive sideways bend in four mutually perpendicular directions to measure the corresponding impedance value (including the resistance and the reactance). The results indicated that the impedance value showed the same trend as the resistance, implying that the impedance was primarily affected by the resistance. The impedance value for the instruments in the 80% and 60% TLL groups increased by about 6 mΩ (about 7.5%) more than that of the instruments in the intact and 40% TLL groups. The SEM analysis result showed that crack striations were only found at the tip of the thread on the cracked surface of the instrument, consistent with the impedance measurements that found the impedance value of the cracked surface to be significantly different from those in other surfaces. These findings indicate that the impedance value may represent an effective parameter for evaluating the micro-structural status of Ni-Ti rotary instruments subjected to fatigue loading. PMID:21251866

  13. Exploratory nondestructive evaluation (NDE) research for advanced materials and processes: Volume 3 -- Interactive multimedia computer based training (IMCBT) for nondestructive evaluation/inspection (NDE/I) personnel. Final report, 1 July 1995--30 April 1998

    SciTech Connect

    Bossi; Knutson, B.; Nerenberg, R.; Deobald, L.; Nelson, J.

    1998-07-01

    Interactive Multimedia Computer Based Training (IMCBT) for Nondestructive Inspection (NDE/I) Personnel: Computer Based Training (CBT) is a highly effective method for industrial training that has been growing in popularity. Text, graphics, sound, movies and animation enhance the learning activity. Interactive Multimedia CBT (IMCBT) allows students to learn in an environment where the training material is presented on a computer workstation and uses student interaction and feedback in the learning process. This technology has been used in the aerospace industry for aircraft maintenance and flight training and is growing in many operation training areas. The cost of development of IMCBT material is significantly more expensive than traditional training material, but an hour of IMCBT material can contain more information than an hour of traditional training material since information is transferred faster and with higher retention. Because IMCBT delivers training at lower cost, the overall benefit of IMCBT has been found to be in the range of 40% to 60% cost savings. The application of IMCBT for NDE/I training did show an overwhelmingly positive acceptance of the incorporation of IMCBT for NDE/I personnel within existing training structures. A CD-ROM package called INSPECT (Interactive Student Paced Eddy Current Training) has demonstrate various advanced aspects of potential IMCBT lessons. The INSPECT CD demonstration was reviewed by Air Force and industry professionals, as well as a group of high school students to gauge novice response. The prototype was found to be appealing and to have significant potential as a useful teaching tool. A large majority of the professional reviewers stated they would like to have complete CBT modules like INSPECT for some aspect of their NDE/I training.

  14. The role of quantitative safety evaluation in regulatory decision making of drugs.

    PubMed

    Chakravarty, Aloka G; Izem, Rima; Keeton, Stephine; Kim, Clara Y; Levenson, Mark S; Soukup, Mat

    2016-01-01

    Evaluation of safety is a critical component of drug review at the US Food and Drug Administration (FDA). Statisticians are playing an increasingly visible role in quantitative safety evaluation and regulatory decision-making. This article reviews the history and the recent events relating to quantitative drug safety evaluation at the FDA. The article then focuses on five active areas of quantitative drug safety evaluation and the role Division of Biometrics VII (DBVII) plays in these areas, namely meta-analysis for safety evaluation, large safety outcome trials, post-marketing requirements (PMRs), the Sentinel Initiative, and the evaluation of risk from extended/long-acting opioids. This article will focus chiefly on developments related to quantitative drug safety evaluation and not on the many additional developments in drug safety in general. PMID:26372792

  15. Nondestructive testing potential evaluation of a terahertz frequency-modulated continuous-wave imager for composite materials inspection

    NASA Astrophysics Data System (ADS)

    Cristofani, Edison; Friederich, Fabian; Wohnsiedler, Sabine; Matheis, Carsten; Jonuscheit, Joachim; Vandewal, Marijke; Beigang, René

    2014-03-01

    The sub-terahertz (THz) frequency band has proved to be a noteworthy option for nondestructive testing (NDT) of nonmetal aeronautics materials. Composite structures or laminates can be inspected for foreign objects (water or debris), delaminations, debonds, etc., using sub-THz sensors during the manufacturing process or maintenance. Given the harmless radiation to the human body of this frequency band, no special security measures are needed for operation. Moreover, the frequency-modulated continuous-wave sensor used in this study offers a very light, compact, inexpensive, and high-performing solution. An automated two-dimensional scanner carrying three sensors partially covering the 70- to 320-GHz band is operated, using two complementary measurement approaches: conventional focused imaging, where focusing lenses are used; and synthetic aperture (SA) or unfocused wide-beam imaging, for which lenses are no longer needed. Conventional focused imagery offers finer spatial resolutions but imagery is depth-limited due to the beam waist effect, whereas SA measurements allow imaging of thicker samples with depth-independent but coarser spatial resolutions. The present work is a compendium of a much larger study and describes the key technical aspects of the proposed imaging techniques and reports on results obtained from human-made samples (A-sandwich, C-sandwich, solid laminates) which include diverse defects and damages typically encountered in aeronautics multilayered structures. We conclude with a grading of the achieved results in comparison with measurements performed by other NDT techniques on the same samples.

  16. Quantitative, Notional, and Comprehensive Evaluations of Spontaneous Engaged Speech

    ERIC Educational Resources Information Center

    Molholt, Garry; Cabrera, Maria Jose; Kumar, V. K.; Thompsen, Philip

    2011-01-01

    This study provides specific evidence regarding the extent to which quantitative measures, common sense notional measures, and comprehensive measures adequately characterize spontaneous, although engaged, speech. As such, the study contributes to the growing body of literature describing the current limits of automatic systems for evaluating…

  17. QUANTITATIVE GENETIC ACTIVITY GRAPHICAL PROFILES FOR USE IN CHEMICAL EVALUATION

    EPA Science Inventory

    A graphic approach termed a Genetic Activity Profile (GAP) has been developed to display a matrix of data on the genetic and related effects of selected chemical agents. he profiles provide a visual overview of the quantitative (doses) and qualitative (test results) data for each...

  18. Quantitative fault tree analysis using the Set Evaluation Program (SEP)

    SciTech Connect

    Olman, M.D.

    1982-09-01

    This report describes the use of a program to aid in the analysis of fault trees. The user has the option of executing one or more of a number of procedures which have been developed to perform the quantitative analysis of a fault tree.

  19. Quantitative ultrasonic evaluation of concrete structures using one-sided access

    NASA Astrophysics Data System (ADS)

    Khazanovich, Lev; Hoegh, Kyle

    2016-02-01

    Nondestructive diagnostics of concrete structures is an important and challenging problem. A recent introduction of array ultrasonic dry point contact transducer systems offers opportunities for quantitative assessment of the subsurface condition of concrete structures, including detection of defects and inclusions. The methods described in this paper are developed for signal interpretation of shear wave impulse response time histories from multiple fixed distance transducer pairs in a self-contained ultrasonic linear array. This included generalizing Kirchoff migration-based synthetic aperture focusing technique (SAFT) reconstruction methods to handle the spatially diverse transducer pair locations, creating expanded virtual arrays with associated reconstruction methods, and creating automated reconstruction interpretation methods for reinforcement detection and stochastic flaw detection. Interpretation of the reconstruction techniques developed in this study were validated using the results of laboratory and field forensic studies. Applicability of the developed methods for solving practical engineering problems was demonstrated.

  20. Quantitative autoradiographic microimaging in the development and evaluation of radiopharmaceuticals

    SciTech Connect

    Som, P.; Oster, Z.H.

    1994-04-01

    Autoradiographic (ARG) microimaging is the method for depicting biodistribution of radiocompounds with highest spatial resolution. ARG is applicable to gamma, positron and negatron emitting radiotracers. Dual or multiple-isotope studies can be performed using half-lives and energies for discrimination of isotopes. Quantitation can be performed by digital videodensitometry and by newer filmless technologies. ARG`s obtained at different time intervals provide the time dimension for determination of kinetics.

  1. Shearography in Experimental Mechanics and Nondestructive Testing

    NASA Astrophysics Data System (ADS)

    Hung, Y. Y.

    This paper reviews shearography and its applications in experimental mechanics and nondestructive testing. Shearography is an interferometric method for measuring surface displacement derivatives. Unlike holography, it does not require special vibration isolation; hence it can be employed in field/factory environments. The technique has already received wide industrial acceptance for nondestructive testing. Other applications include strain measurement, material characterization, residual stress evaluation, vibration studies and 3D shape measurement.

  2. Evaluation of halftone techniques using psychovisual testing and quantitative quality measures

    NASA Astrophysics Data System (ADS)

    Mitsa, Theophano

    1992-08-01

    The quality of an image can be evaluated by performing a psychovisual test or by using quantitative quality measures. In order to assess the performance of different halftone techniques, gray scale images are halftoned in various ways and then presented to human viewers for quality evaluation. Quantitative quality criteria, such as edge correlation, mean square error and local error measures are also used for quality evaluation of the halftone images. Since the ultimate judges of image quality are human viewers, the success of these quantitative criteria as quality measures for halftones is assessed by comparing their results with the results of the psychovisual test.

  3. Quantitative evaluation of the kinetics of human enamel simulated caries using photothermal radiometry and modulated luminescence

    NASA Astrophysics Data System (ADS)

    Hellen, Adam; Mandelis, Andreas; Finer, Yoav; Amaechi, Bennett T.

    2011-07-01

    Photothermal radiometry and modulated luminescence (PTR-LUM) is an emerging nondestructive methodology applied toward the characterization and quantification of dental caries. We evaluate the efficacy of PTR-LUM in vitro to detect, monitor, and quantify human enamel caries. Artificial caries are created in extracted human molars (n = 15) using an acidified gel system (pH 4.5) for 10 or 40 days. PTR-LUM frequency scans (1 Hz-1 kHz) are performed before and during demineralization. Transverse microradiography (TMR) analysis, the current gold standard, follows at treatment conclusion to determine the mineral loss and depth of the artificially demineralized lesions. A theoretical model is applied to PTR experimental data to evaluate the changes in optothermophysical properties of demineralized enamel as a function of time. Higher optical scattering coefficients and poorer thermophysical properties are characteristic of the growing demineralized lesions, as verified by TMR, where the generated microporosities of the subsurface lesion confine the thermal-wave centroid. Enhanced optical scattering coefficients of demineralized lesions result in poorer luminescence yield due to scattering of both incident and converted luminescent photons. PTR-LUM sensitivity to changes in tooth mineralization coupled with opto-thermophysical property extraction illustrates the technique's potential for nondestructive quantification of enamel caries.

  4. Advanced NDE techniques for quantitative characterization of aircraft

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S.; Winfree, William P.

    1990-01-01

    Recent advances in nondestructive evaluation (NDE) at NASA Langley Research Center and their applications that have resulted in quantitative assessment of material properties based on thermal and ultrasonic measurements are reviewed. Specific applications include ultrasonic determination of bolt tension, ultrasonic and thermal characterization of bonded layered structures, characterization of composite materials, and disbonds in aircraft skins.

  5. Homogenized tissue phantoms for quantitative evaluation of subsurface fluorescence contrast.

    PubMed

    Roy, Mathieu; Kim, Anthony; Dadani, Farhan; Wilson, Brian C

    2011-01-01

    The use of phantoms comprising diluted tissue homogenates with a buried capillary containing quantum dots is demonstrated as a method to investigate the optical and biophysical factors influencing the imaging of subsurface fluorescence contrast agents. Validation of the method is demonstrated using both liquid phantoms of known optical absorption and reduced scattering and Monte Carlo computer simulations of photon transport. Conclusions regarding the optimal excitation wavelength are given and quantified with respect to the tissue optical properties. The tissue homogenate method should be of value for quantitative optimization studies relevant to, for example, endoscopic imaging. PMID:21280919

  6. Comprehensive quantitative evaluation of FLIM-FRET microscopy

    NASA Astrophysics Data System (ADS)

    Wallrabe, Horst; Sun, Yuangsheng; Svindrych, Zdenek; Periasamy, Ammasi

    2015-03-01

    Average lifetime between the usually bi-exponential double-label specimen and a mono-exponential single donor sample serves as a basis for the calculation of the average energy transfer efficiency (E). This semi-quantitative approach however does not fully explore cellular functions, such as endosomal pH differences, specific morphological features, examining sub-populations and the like. We applied a different, quantitative Region-of-Interest (ROI)-based method in 2 live-cell assays by TCSPC FLIM-FRET microscopy: a 5 amino-acid linked FRET standard and mouse pituitary cells expressing a dimerized C/EBPα-bZip transcription factor in the nucleus, both tagged with Cerulean (C) and Venus (V). ROIs with different selection thresholds were generated and compared. Average lifetimes are similar, but ratios between them and other subtle differences are revealed by comprehensive distribution information. Following published references, we also explored 3 different methods to calculate FLIM-FRET energy transfer efficiencies for the Cerulean- Venus constructs, producing differences and supporting the long-held notion that E is called 'apparent' efficiency. FRET's greatest contribution continues to be exploring changes taking place at the cellular level and quantifying differences in relative terms between control and variables.

  7. Quantitative evaluation of bioorthogonal chemistries for surface functionalization of nanoparticles.

    PubMed

    Feldborg, Lise N; Jølck, Rasmus I; Andresen, Thomas L

    2012-12-19

    We present here a highly efficient and chemoselective liposome functionalization method based on oxime bond formation between a hydroxylamine and an aldehyde-modified lipid component. We have conducted a systematic and quantitative comparison of this new approach with other state-of-the-art conjugation reactions in the field. Targeted liposomes that recognize overexpressed receptors or antigens on diseased cells have great potential in therapeutic and diagnostic applications. However, chemical modifications of nanoparticle surfaces by postfunctionalization approaches are less effective than in solution and often not high-yielding. In addition, the conjugation efficiency is often challenging to characterize and therefore not addressed in many reports. We present here an investigation of PEGylated liposomes functionalized with a neuroendocrine tumor targeting peptide (TATE), synthesized with a variety of functionalities that have been used for surface conjugation of nanoparticles. The reaction kinetics and overall yield were quantified by HPLC. Reactions were conducted in solution as well as by postfunctionalization of liposomes in order to study the effects of steric hindrance and possible affinity between the peptide and the liposome surface. These studies demonstrate the importance of choosing the correct chemistry in order to obtain a quantitative surface functionalization of liposomes. PMID:23153257

  8. Quantitative analytical method to evaluate the metabolism of vitamin D.

    PubMed

    Mena-Bravo, A; Ferreiro-Vera, C; Priego-Capote, F; Maestro, M A; Mouriño, A; Quesada-Gómez, J M; Luque de Castro, M D

    2015-03-10

    A method for quantitative analysis of vitamin D (both D2 and D3) and its main metabolites - monohydroxylated vitamin D (25-hydroxyvitamin D2 and 25-hydroxyvitamin D3) and dihydroxylated metabolites (1,25-dihydroxyvitamin D2, 1,25-dihydroxyvitamin D3 and 24,25-dihydroxyvitamin D3) in human serum is here reported. The method is based on direct analysis of serum by an automated platform involving on-line coupling of a solid-phase extraction workstation to a liquid chromatograph-tandem mass spectrometer. Detection of the seven analytes was carried out by the selected reaction monitoring (SRM) mode, and quantitative analysis was supported on the use of stable isotopic labeled internal standards (SIL-ISs). The detection limits were between 0.3-75pg/mL for the target compounds, while precision (expressed as relative standard deviation) was below 13.0% for between-day variability. The method was externally validated according to the vitamin D External Quality Assurance Scheme (DEQAS) through the analysis of ten serum samples provided by this organism. The analytical features of the method support its applicability in nutritional and clinical studies targeted at elucidating the role of vitamin D metabolism. PMID:25575651

  9. A review of methods for quantitative evaluation of axial vertebral rotation

    PubMed Central

    Pernuš, Franjo; Likar, Boštjan

    2009-01-01

    Quantitative evaluation of axial vertebral rotation is essential for the determination of reference values in normal and pathological conditions and for understanding the mechanisms of the progression of spinal deformities. However, routine quantitative evaluation of axial vertebral rotation is difficult and error-prone due to the limitations of the observer, characteristics of the observed vertebral anatomy and specific imaging properties. The scope of this paper is to review the existing methods for quantitative evaluation of axial vertebral rotation from medical images along with all relevant publications, which may provide a valuable resource for studying the existing methods or developing new methods and evaluation strategies. The reviewed methods are divided into the methods for evaluation of axial vertebral rotation in 2D images and the methods for evaluation of axial vertebral rotation in 3D images. Key evaluation issues and future considerations, supported by the results of the overview, are also discussed. PMID:19242736

  10. A New Simple Interferometer for Obtaining Quantitatively Evaluable Flow Patterns

    NASA Technical Reports Server (NTRS)

    Erdmann, S F

    1953-01-01

    The method described in the present report makes it possible to obtain interferometer records with the aid of any one of the available Schlieren optics by the addition of very simple expedients, which fundamentally need not to be inferior to those obtained by other methods, such as the Mach-Zehnder interferometer, for example. The method is based on the fundamental concept of the phase-contrast process developed by Zernike, but which in principle has been enlarged to such an extent that it practically represents an independent interference method for general applications. Moreover, the method offers the possibility, in case of necessity, of superposing any apparent wedge field on the density field to be gauged. The theory is explained on a purely physical basis and illustrated and proved by experimental data. A number of typical cases are cited and some quantitative results reported.

  11. Quantitative evaluation of magnetic immunoassay with remanence measurement

    NASA Astrophysics Data System (ADS)

    Enpuku, K.; Soejima, K.; Nishimoto, T.; Kuma, H.; Hamasaki, N.; Tsukamoto, A.; Saitoh, K.; Kandori, A.

    2006-05-01

    Magnetic immunoassays utilizing magnetic markers and a high -Tc SQUID have been performed. The marker was designed so as to generate remanence, and its remanence field was measured with the SQUID. The SQUID system was developed so as to measure 12 samples in one measurement sequence. We first conducted a detection of antigen called human IgE using IgE standard solution, and showed the detection of IgE down to 2 attomol. The binding process between IgE and the marker could be semi-quantitatively explained with the Langmuir-type adsorption model. We also measured IgE in human serums, and demonstrated the usefulness of the present method for practical diagnosis.

  12. A new fiber-optic non-contact compact laser-ultrasound scanner for fast non-destructive testing and evaluation of aircraft composites

    NASA Astrophysics Data System (ADS)

    Pelivanov, Ivan; Buma, Takashi; Xia, Jinjun; Wei, Chen-Wei; O'Donnell, Matthew

    2014-03-01

    Laser ultrasonic (LU) inspection represents an attractive, non-contact method to evaluate composite materials. Current non-contact systems, however, have relatively low sensitivity compared to contact piezoelectric detection. They are also difficult to adjust, very expensive, and strongly influenced by environmental noise. Here, we demonstrate that most of these drawbacks can be eliminated by combining a new generation of compact, inexpensive fiber lasers with new developments in fiber telecommunication optics and an optimally designed balanced probe scheme. In particular, a new type of a balanced fiber-optic Sagnac interferometer is presented as part of an all-optical LU pump-probe system for non-destructive testing and evaluation of aircraft composites. The performance of the LU system is demonstrated on a composite sample with known defects. Wide-band ultrasound probe signals are generated directly at the sample surface with a pulsed fiber laser delivering nanosecond laser pulses at a repetition rate up to 76 kHz rate with a pulse energy of 0.6 mJ. A balanced fiber-optic Sagnac interferometer is employed to detect pressure signals at the same point on the composite surface. A- and B-scans obtained with the Sagnac interferometer are compared to those made with a contact wide-band polyvinylidene fluoride transducer.

  13. A new fiber-optic non-contact compact laser-ultrasound scanner for fast non-destructive testing and evaluation of aircraft composites

    PubMed Central

    Pelivanov, Ivan; Buma, Takashi; Xia, Jinjun; Wei, Chen-Wei; O'Donnell, Matthew

    2014-01-01

    Laser ultrasonic (LU) inspection represents an attractive, non-contact method to evaluate composite materials. Current non-contact systems, however, have relatively low sensitivity compared to contact piezoelectric detection. They are also difficult to adjust, very expensive, and strongly influenced by environmental noise. Here, we demonstrate that most of these drawbacks can be eliminated by combining a new generation of compact, inexpensive fiber lasers with new developments in fiber telecommunication optics and an optimally designed balanced probe scheme. In particular, a new type of a balanced fiber-optic Sagnac interferometer is presented as part of an all-optical LU pump-probe system for non-destructive testing and evaluation of aircraft composites. The performance of the LU system is demonstrated on a composite sample with known defects. Wide-band ultrasound probe signals are generated directly at the sample surface with a pulsed fiber laser delivering nanosecond laser pulses at a repetition rate up to 76 kHz rate with a pulse energy of 0.6 mJ. A balanced fiber-optic Sagnac interferometer is employed to detect pressure signals at the same point on the composite surface. A- and B-scans obtained with the Sagnac interferometer are compared to those made with a contact wide-band polyvinylidene fluoride transducer. PMID:24737921

  14. Nondestructive characterization of fatigue damage with thermography

    NASA Astrophysics Data System (ADS)

    Roesner, Henrik; Sathish, Shamachary; Meyendorf, Norbert

    2001-08-01

    A thermal imaging NDE method has been developed for nondestructive characterization of early stages of fatigue damage. The method is based on evaluation of the thermal effects induced in a material by a short-term mechanical loading. The mechanical loading causes in addition to thermoelastic temperature change, an increase due to heat dissipation that depends upon the microstructure of the material in a characteristic manner. The origin of this heat dissipation is the mechanical damping process. Utilizing the initial temperature rise due to a short-term mechanical loading, the dissipated energy per cycle was evaluated as a thermal parameter. This new thermal NDE parameter allows a quantitative characterization of the mechanical hysteresis, without the need for calibration to eliminate influences of thermal boundary conditions. The measurement of the thermal NDE parameters has been performed on Ti-6Al-4V dog-bone specimens, fatigued in low cycle fatigue (LCF) as well as in high cycle fatigue (HCF) experiments. Characteristic dependence of the NDE parameters on the already accumulated fatigue damage has been observed. The advantage of the thermal method is the applicability to components under service conditions because of simplicity, rapid measurements (a few seconds) and the ability of locally resolved evaluations.

  15. Online versus Paper Evaluations: Differences in Both Quantitative and Qualitative Data

    ERIC Educational Resources Information Center

    Burton, William B.; Civitano, Adele; Steiner-Grossman, Penny

    2012-01-01

    This study sought to determine if differences exist in the quantitative and qualitative data collected with paper and online versions of a medical school clerkship evaluation form. Data from six-and-a-half years of clerkship evaluations were used, some collected before and some after the conversion from a paper to an online evaluation system. The…

  16. Quantitative analysis method to evaluate optical clearing effect of skin using a hyperosmotic chemical agent.

    PubMed

    Yoon, Jinhee; Son, Taeyoon; Jung, Byungjo

    2007-01-01

    Light penetration depth in highly scattering tissues can be increased by using hyperosmotic chemical agents such as glycerol, PEG (polyethylene glycol) and glucose. Previous many studies used OCT, spectrometer, integrating method to quantitatively evaluate the optical clearing effect of skin. In this study, we show the optical clearing effect of skin using glycerol and suggest a new quantitative analysis method to evaluate the spatial optical clearing effect of skin using glycerol. PMID:18002713

  17. A lighting metric for quantitative evaluation of accent lighting systems

    NASA Astrophysics Data System (ADS)

    Acholo, Cyril O.; Connor, Kenneth A.; Radke, Richard J.

    2014-09-01

    Accent lighting is critical for artwork and sculpture lighting in museums, and subject lighting for stage, Film and television. The research problem of designing effective lighting in such settings has been revived recently with the rise of light-emitting-diode-based solid state lighting. In this work, we propose an easy-to-apply quantitative measure of the scene's visual quality as perceived by human viewers. We consider a well-accent-lit scene as one which maximizes the information about the scene (in an information-theoretic sense) available to the user. We propose a metric based on the entropy of the distribution of colors, which are extracted from an image of the scene from the viewer's perspective. We demonstrate that optimizing the metric as a function of illumination configuration (i.e., position, orientation, and spectral composition) results in natural, pleasing accent lighting. We use a photorealistic simulation tool to validate the functionality of our proposed approach, showing its successful application to two- and three-dimensional scenes.

  18. Preprocessing of Edge of Light images: towards a quantitative evaluation

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Forsyth, David S.; Marincak, Anton

    2003-08-01

    A computer vision inspection system, named Edge of Light TM (EOL), was invented and developed at the Institute for Aerospace Research of the National Research Council Canada. One application of interest is the detection and quantitative measurement of "pillowing" caused by corrosion in the faying surfaces of aircraft fuselage joints. To quantify the hidden corrosion, one approach is to relate the average corrosion of a region to the peak-to-peak amplitude between two diagonally adjacent rivet centers. This raises the requirement for automatically locating the rivet centers. The first step to achieve this is the rivet edge detection. In this study, gradient-based edge detection, local energy based feature extraction, and an adaptive threshold method were employed to identify the edge of rivets, which facilitated the first step in the EOL quantification procedure. Furthermore, the brightness profile is processed by the derivative operation, which locates the pillowing along the scanning direction. The derivative curves present an estimation of the inspected surface.

  19. Predictive Heterosis in Multibreed Evaluations Using Quantitative and Molecular Approaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heterosis is the extra genetic boost in performance obtained by crossing two cattle breeds. It is an important tool for increasing the efficiency of beef production. It is also important to adjust data used to calculate genetic evaluations for differences in heterosis. Good estimates of heterosis...

  20. A Quantitative Investigation of Stakeholder Variation in Training Program Evaluation.

    ERIC Educational Resources Information Center

    Michalski, Greg V.

    A survey was conducted to investigate variation in stakeholder perceptions of training results and evaluation within the context of a high-technology product development firm (the case organization). A scannable questionnaire survey booklet was developed and scanned data were exported and analyzed. Based on an achieved sample of 280 (70% response…

  1. Quantitative evaluation of the major determinants of human gait.

    PubMed

    Lin, Yi-Chung; Gfoehler, Margit; Pandy, Marcus G

    2014-04-11

    Accurate knowledge of the isolated contributions of joint movements to the three-dimensional displacement of the center of mass (COM) is fundamental for understanding the kinematics of normal walking and for improving the treatment of gait disabilities. Saunders et al. (1953) identified six kinematic mechanisms to explain the efficient progression of the whole-body COM in the sagittal, transverse, and coronal planes. These mechanisms, referred to as the major determinants of gait, were pelvic rotation, pelvic list, stance knee flexion, foot and knee mechanisms, and hip adduction. The aim of the present study was to quantitatively assess the contribution of each major gait determinant to the anteroposterior, vertical, and mediolateral displacements of the COM over one gait cycle. The contribution of each gait determinant was found by applying the concept of an 'influence coefficient', wherein the partial derivative of the COM displacement with respect to a prescribed determinant was calculated. The analysis was based on three-dimensional measurements of joint angular displacements obtained from 23 healthy young adults walking at slow, normal and fast speeds. We found that hip flexion, stance knee flexion, and ankle-foot interaction (comprised of ankle plantarflexion, toe flexion and the displacement of the center of pressure) are the major determinants of the displacements of the COM in the sagittal plane, while hip adduction and pelvic list contribute most significantly to the mediolateral displacement of the COM in the coronal plane. Pelvic rotation and pelvic list contribute little to the vertical displacement of the COM at all walking speeds. Pelvic tilt, hip rotation, subtalar inversion, and back extension, abduction and rotation make negligible contributions to the displacements of the COM in all three anatomical planes. PMID:24582352

  2. Photoacoustic microscopy for quantitative evaluation of angiogenesis inhibitor

    NASA Astrophysics Data System (ADS)

    Chen, Sung-Liang; Burnett, Joseph; Sun, Duxin; Xie, Zhixing; Wang, Xueding

    2014-03-01

    We present the photoacoustic microscopy (PAM) for evaluation of angiogenesis inhibitors on a chick embryo model. Microvasculature in the chorioallantoic membrane (CAM) of the chick embryos was imaged by PAM, and the optical microscopy (OM) images of the same set of CAMs were also acquired for comparisons, serving for validation of the results from PAM. The angiogenesis inhibitors, Sunitinib, with different concentrations applied to the CAM result in the change in microvascular density, which was quantified by both PAM and OM imaging. Similar change in microvascular density from PAM and OM imaging in response to angiogenesis inhibitor at different doses was observed, demonstrating that PAM has potential to provide objective evaluation of anti-angiogenesis medication. Besides, PAM is advantageous in three-dimensional and functional imaging compared with OM so that the emerging PAM technique may offer unique information on the efficacy of angiogenesis inhibitors and could benefit applications related to antiangiogenesis treatments.

  3. Quantitative vertebral compression fracture evaluation using a height compass

    NASA Astrophysics Data System (ADS)

    Yao, Jianhua; Burns, Joseph E.; Wiese, Tatjana; Summers, Ronald M.

    2012-03-01

    Vertebral compression fractures can be caused by even minor trauma in patients with pathological conditions such as osteoporosis, varying greatly in vertebral body location and compression geometry. The location and morphology of the compression injury can guide decision making for treatment modality (vertebroplasty versus surgical fixation), and can be important for pre-surgical planning. We propose a height compass to evaluate the axial plane spatial distribution of compression injury (anterior, posterior, lateral, and central), and distinguish it from physiologic height variations of normal vertebrae. The method includes four steps: spine segmentation and partition, endplate detection, height compass computation and compression fracture evaluation. A height compass is computed for each vertebra, where the vertebral body is partitioned in the axial plane into 17 cells oriented about concentric rings. In the compass structure, a crown-like geometry is produced by three concentric rings which are divided into 8 equal length arcs by rays which are subtended by 8 common central angles. The radius of each ring increases multiplicatively, with resultant structure of a central node and two concentric surrounding bands of cells, each divided into octants. The height value for each octant is calculated and plotted against octants in neighboring vertebrae. The height compass shows intuitive display of the height distribution and can be used to easily identify the fracture regions. Our technique was evaluated on 8 thoraco-abdominal CT scans of patients with reported compression fractures and showed statistically significant differences in height value at the sites of the fractures.

  4. Non-destructive evaluation of an internal adaptation of resin composite restoration with swept-source optical coherence tomography and micro-CT.

    PubMed

    Han, Seung-Hoon; Sadr, Alireza; Tagami, Junji; Park, Sung-Ho

    2016-01-01

    Swept-source optical coherence tomography (SS-OCT) and micro-CT can be useful non-destructive methods for evaluating internal adaptation. There is no comparative study evaluating the two methods in the assessment of internal adaptation in composite restoration. The purpose of this study was to compare internal adaptation measurements of SS-OCT and micro-CT. Two cylindrical cavities were created on the labial surface of twelve bovine incisors. The 24 cavities were randomly assigned to four groups of dentin adhesives: (1) three-step etch-and-rinse adhesive, (2) two-step etch-and-rinse adhesive, (3) two-step self-etch adhesive, and (4) one-step self-etch adhesive. After application, the cavities were filled with resin composite. All restorations underwent a thermocycling challenge, and then, eight SS-OCT images were taken using a Santec OCT-2000™ (Santec Co., Komaki, Japan). The internal adaptation was also evaluated using micro-CT (Skyscan, Aartselaar, Belgium). The image analysis was used to calculate the percentage of defective spot (%DS) and compare the results. The groups were compared using one-way ANOVA with Duncan analysis at the 95% significance level. The SS-OCT and micro-CT measurements were compared with a paired t-test, and the relationship was analyzed using a Pearson correlation test at the 95% significance level. The %DS results showed that Group 3≤Group 4

  5. ED-XRF analysis for Cultural Heritage: is quantitative evaluation always essential?

    NASA Astrophysics Data System (ADS)

    Bonizzoni, L.

    2015-07-01

    Energy Dispersive X-Ray Fluorescence (ED-XRF) is a very suitable tool for examination of Cultural Heritage materials because of its simplicity, with no requirement for any sample preparation and the possibility of operating with portable instruments, and it can probably be considered the most useful non-destructive analytical technique for ancient valuable objects of archaeological, historical or artistic interest. As regards the possibility of getting quantitative analysis in archaeometric applications, the problems arising from the limited sensitivity in detecting low Z elements, the irregular shape or the non-homogeneous composition of the sample have generated a widespread opinion that only semi-quantitative analyses are possible in XRF applications to archaeometry. In fact, this is always true for non-homogeneous samples as, typically, painting layers. On the contrary, the problems deriving from limited sensitivity in detecting matrix light elements as well as from irregular surface under analysis can be solved in most cases. Notwithstanding, working on unique and not standardized objects requires to pay attention on details and to know how to choose correct parameters and calculation algorithms to obtain reliable results. Indeed opportunities to deal with these objects are very limited and results have implication in other fields, so that each information about materials and production technique is of great interest. Two typical materials of archaeological interest showing particular features are considered - namely high corroded metallic artefacts and ceramics - revealing that, even if in cultural heritage field detailed quantitative analysis is the goal, it is not always necessary as also qualitative information by XRF spectra increase the knowledge of artefact.

  6. A quantitative evaluation of two methods for preserving hair samples

    USGS Publications Warehouse

    Roon, D.A.; Waits, L.P.; Kendall, K.C.

    2003-01-01

    Hair samples are an increasingly important DNA source for wildlife studies, yet optimal storage methods and DNA degradation rates have not been rigorously evaluated. We tested amplification success rates over a one-year storage period for DNA extracted from brown bear (Ursus arctos) hair samples preserved using silica desiccation and -20C freezing. For three nuclear DNA microsatellites, success rates decreased significantly after a six-month time point, regardless of storage method. For a 1000 bp mitochondrial fragment, a similar decrease occurred after a two-week time point. Minimizing delays between collection and DNA extraction will maximize success rates for hair-based noninvasive genetic sampling projects.

  7. Object-oriented fault tree evaluation program for quantitative analyses

    NASA Technical Reports Server (NTRS)

    Patterson-Hine, F. A.; Koen, B. V.

    1988-01-01

    Object-oriented programming can be combined with fault free techniques to give a significantly improved environment for evaluating the safety and reliability of large complex systems for space missions. Deep knowledge about system components and interactions, available from reliability studies and other sources, can be described using objects that make up a knowledge base. This knowledge base can be interrogated throughout the design process, during system testing, and during operation, and can be easily modified to reflect design changes in order to maintain a consistent information source. An object-oriented environment for reliability assessment has been developed on a Texas Instrument (TI) Explorer LISP workstation. The program, which directly evaluates system fault trees, utilizes the object-oriented extension to LISP called Flavors that is available on the Explorer. The object representation of a fault tree facilitates the storage and retrieval of information associated with each event in the tree, including tree structural information and intermediate results obtained during the tree reduction process. Reliability data associated with each basic event are stored in the fault tree objects. The object-oriented environment on the Explorer also includes a graphical tree editor which was modified to display and edit the fault trees.

  8. Computerized quantitative evaluation of mammographic accreditation phantom images

    SciTech Connect

    Lee, Yongbum; Tsai, Du-Yih; Shinohara, Norimitsu

    2010-12-15

    Purpose: The objective was to develop and investigate an automated scoring scheme of the American College of Radiology (ACR) mammographic accreditation phantom (RMI 156, Middleton, WI) images. Methods: The developed method consisted of background subtraction, determination of region of interest, classification of fiber and mass objects by Mahalanobis distance, detection of specks by template matching, and rule-based scoring. Fifty-one phantom images were collected from 51 facilities for this study (one facility provided one image). A medical physicist and two radiologic technologists also scored the images. The human and computerized scores were compared. Results: In terms of meeting the ACR's criteria, the accuracies of the developed method for computerized evaluation of fiber, mass, and speck were 90%, 80%, and 98%, respectively. Contingency table analysis revealed significant association between observer and computer scores for microcalcifications (p<5%) but not for masses and fibers. Conclusions: The developed method may achieve a stable assessment of visibility for test objects in mammographic accreditation phantom image in whether the phantom image meets the ACR's criteria in the evaluation test, although there is room left for improvement in the approach for fiber and mass objects.

  9. Quantitative evaluation of mechanosensing of cells on dynamically tunable hydrogels.

    PubMed

    Yoshikawa, Hiroshi Y; Rossetti, Fernanda F; Kaufmann, Stefan; Kaindl, Thomas; Madsen, Jeppe; Engel, Ulrike; Lewis, Andrew L; Armes, Steven P; Tanaka, Motomu

    2011-02-01

    Thin hydrogel films based on an ABA triblock copolymer gelator [where A is pH-sensitive poly(2-(diisopropylamino)ethyl methacrylate) (PDPA) and B is biocompatible poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC)] were used as a stimulus-responsive substrate that allows fine adjustment of the mechanical environment experienced by mouse myoblast cells. The hydrogel film elasticity could be reversibly modulated by a factor of 40 via careful pH adjustment without adversely affecting cell viability. Myoblast cells exhibited pronounced stress fiber formation and flattening on increasing the hydrogel elasticity. As a new tool to evaluate the strength of cell adhesion, we combined a picosecond laser with an inverted microscope and utilized the strong shock wave created by the laser pulse to determine the critical pressure required for cell detachment. Furthermore, we demonstrate that an abrupt jump in the hydrogel elasticity can be utilized to monitor how cells adapt their morphology to changes in their mechanical environment. PMID:21218794

  10. Towards the quantitative evaluation of visual attention models.

    PubMed

    Bylinskii, Z; DeGennaro, E M; Rajalingham, R; Ruda, H; Zhang, J; Tsotsos, J K

    2015-11-01

    Scores of visual attention models have been developed over the past several decades of research. Differences in implementation, assumptions, and evaluations have made comparison of these models very difficult. Taxonomies have been constructed in an attempt at the organization and classification of models, but are not sufficient at quantifying which classes of models are most capable of explaining available data. At the same time, a multitude of physiological and behavioral findings have been published, measuring various aspects of human and non-human primate visual attention. All of these elements highlight the need to integrate the computational models with the data by (1) operationalizing the definitions of visual attention tasks and (2) designing benchmark datasets to measure success on specific tasks, under these definitions. In this paper, we provide some examples of operationalizing and benchmarking different visual attention tasks, along with the relevant design considerations. PMID:25951756

  11. Quantitative Evaluation of Strain Near Tooth Fillet by Image Processing

    NASA Astrophysics Data System (ADS)

    Masuyama, Tomoya; Yoshiizumi, Satoshi; Inoue, Katsumi

    The accurate measurement of strain and stress in a tooth is important for the reliable evaluation of the strength or life of gears. In this research, a strain measurement method which is based on image processing is applied to the analysis of strain near the tooth fillet. The loaded tooth is photographed using a CCD camera and stored as a digital image. The displacement of the point in the tooth flank is tracked by the cross-correlation method, and then, the strain is calculated. The interrogation window size of the correlation method and the overlap amount affect the accuracy and resolution. In the case of measurements at structures with complicated profiles such as fillets, the interrogation window maintains a large size and the overlap amount should be large. The surface condition also affects the accuracy. The white painted surface with a small black particle is suitable for measurement.

  12. Qualitative-Quantitative Interactive Continuum: A Model and Application to Teacher Education Evaluation.

    ERIC Educational Resources Information Center

    Benz, Carolyn R.; Newman, Isadore

    This paper presents a model for qualitative and quantitative evaluation research that has been used in a preliminary way in evaluating a teacher education program. The model is based on three underlying constructs which are hierarchical in nature: (1) the assumption that the question of interest always must dictate the structure of the research…

  13. Non-destructive evaluation of fiber-reinforced composites with a fast 2D fiber-optic laser-ultrasound scanner

    NASA Astrophysics Data System (ADS)

    Pelivanov, Ivan; Buma, Takashi; Xia, Jinjun; Wei, Chen-Wei; Shtokolov, Alex; O'Donnell, Matthew

    2015-03-01

    Laser ultrasonic (LU) inspection represents an attractive, non-contact method to evaluate composite materials. Current non-contact systems, however, have relatively low sensitivity compared to contact piezoelectric detection. They are also difficult to adjust, very expensive, and strongly influenced by environmental noise. Here, we demonstrate that most of these drawbacks can be eliminated by combining a new generation of compact, inexpensive fiber lasers with new developments in fiber telecommunication optics and an optimally designed balanced probe scheme. In particular, a new type of a balanced fiber-optic Sagnac interferometer is presented as part of an all-optical LU pump-probe system for high speed non-destructive testing and evaluation (NDT&E) of aircraft composites. The performance of the LU system is demonstrated on a composite sample typically used in the aircraft industry. Wide-band ultrasound probe signals are generated directly at the sample surface with a pulsed diode-pumped laser delivering nanosecond laser pulses at a 1 kHz repetition rate with a pulse energy of 2 mJ. A balanced fiber-optic Sagnac interferometer is employed to detect pressure signals in a 1-10 MHz frequency range at the same point (an 8 μm focal spot) on the composite surface. A fast (up to 100 mm/s) 2D translation system is employed to move the sample during scanning and produce a complete B-scan consisting of one thousand A-scans in less than a second. The sensitivity of this system, in terms of the noise equivalent pressure, is found to be only 10 dB above the Nyquist thermal noise limit. To our knowledge, this is the best reported sensitivity for a non-contact ultrasonic detector of this dimension.

  14. Non-destructive electromagnetic-acoustic evaluation methods of anisotropy and elastic properties in structural alloy steel rolled products

    NASA Astrophysics Data System (ADS)

    Muraviev, V. V.; Muravieva, O. V.; Gabbasova, M. A.

    2015-10-01

    Application opportunities of acoustic structural analysis methods for evaluation of elastic properties and anisotropy by the example of cold-rolled sheets and spring steel rods are presented. Methods are based on application of non-contact electromagnetic-acoustic transducers of encircling and laid-on types developed by the authors and measurements of volume, Rayleigh and Lamb waves parameters. The methods developed can be used as a research tool of material structural analysis, anisotropy of properties when choosing heat treatment techniques and conditions, under intensive plastic deformation and other external energy deposition, including non-conventional material production with hierarchy structure and development of new technologies and safe constructions.

  15. Applying Quantitative Approaches to the Formative Evaluation of Antismoking Campaign Messages.

    PubMed

    Parvanta, Sarah; Gibson, Laura; Forquer, Heather; Shapiro-Luft, Dina; Dean, Lorraine; Freres, Derek; Lerman, Caryn; Mallya, Giridhar; Moldovan-Johnson, Mihaela; Tan, Andy; Cappella, Joseph; Hornik, Robert

    2013-12-01

    This article shares an in-depth summary of a formative evaluation that used quantitative data to inform the development and selection of promotional ads for the antismoking communication component of a social marketing campaign. A foundational survey provided cross-sectional data to identify beliefs about quitting smoking that campaign messages should target, as well as beliefs to avoid. Pretesting draft ads against quantitative indicators of message effectiveness further facilitated the selection and rejection of final campaign ads. Finally, we consider lessons learned from the process of balancing quantitative methods and judgment to make formative decisions about more and less promising persuasive messages for campaigns. PMID:24817829

  16. Applying Quantitative Approaches to the Formative Evaluation of Antismoking Campaign Messages

    PubMed Central

    Parvanta, Sarah; Gibson, Laura; Forquer, Heather; Shapiro-Luft, Dina; Dean, Lorraine; Freres, Derek; Lerman, Caryn; Mallya, Giridhar; Moldovan-Johnson, Mihaela; Tan, Andy; Cappella, Joseph; Hornik, Robert

    2014-01-01

    This article shares an in-depth summary of a formative evaluation that used quantitative data to inform the development and selection of promotional ads for the antismoking communication component of a social marketing campaign. A foundational survey provided cross-sectional data to identify beliefs about quitting smoking that campaign messages should target, as well as beliefs to avoid. Pretesting draft ads against quantitative indicators of message effectiveness further facilitated the selection and rejection of final campaign ads. Finally, we consider lessons learned from the process of balancing quantitative methods and judgment to make formative decisions about more and less promising persuasive messages for campaigns. PMID:24817829

  17. Quantitative evaluation of proximal contacts in posterior composite restorations. Part I. Methodology.

    PubMed

    Wang, J C; Hong, J M

    1989-07-01

    An in vivo method of quantitative measuring intertooth distance before and after placement of a Class 2 composite resin restoration has been developed. A Kaman Sciences KD-2611 non-contact displacement measuring system with a 1 U unshield sensor, based upon the variable resistance of eddy current, was used for the intraoral measurement. Quantitative evaluation of proximal wear, therefore, can be made preoperatively, postoperatively, and at subsequent recall interval for posterior composite resin restorations. PMID:2810447

  18. Quantitative evaluation of wrist posture and typing performance: A comparative study of 4 computer keyboards

    SciTech Connect

    Burastero, S.

    1994-05-01

    The present study focuses on an ergonomic evaluation of 4 computer keyboards, based on subjective analyses of operator comfort and on a quantitative analysis of typing performance and wrist posture during typing. The objectives of this study are (1) to quantify differences in the wrist posture and in typing performance when the four different keyboards are used, and (2) to analyze the subjective preferences of the subjects for alternative keyboards compared to the standard flat keyboard with respect to the quantitative measurements.

  19. Quantitative investigation into methods for evaluating neocortical slice viability

    PubMed Central

    2013-01-01

    Background In cortical and hippocampal brain slice experiments, the viability of processed tissue is usually judged by the amplitude of extracellularly-recorded seizure-like event (SLE) activity. Surprisingly, the suitability of this approach for evaluating slice quality has not been objectively studied. Furthermore, a method for gauging the viability of quiescent tissue, in which SLE activity is intentionally suppressed, has not been documented. In this study we undertook to address both of these matters using the zero-magnesium SLE model in neocortical slices. Methods Using zero-magnesium SLE activity as the output parameter, we investigated: 1) changes in the pattern (amplitude, frequency and length) of SLE activity as slice health either deteriorated; or was compromised by altering the preparation methodology and; 2) in quiescent tissue, whether the triggering of high frequency field activity following electrode insertion predicted subsequent development of SLE activity and hence slice viability. Results SLE amplitude was the single most important variable correlating with slice viability, with a value less than 50?V indicative of tissue unlikely to be able to sustain population activity for more than 3060minutes. In quiescent slices, an increase in high frequency field activity immediately after electrode insertion predicted the development of SLE activity in 100% of cases. Furthermore, the magnitude of the increase in spectral power correlated with the amplitude of succeeding SLE activity (R2 40.9%, p?

  20. Nuclear medicine and imaging research (instrumentation and quantitative methods of evaluation). Progress report, January 15, 1992--January 14, 1993

    SciTech Connect

    Beck, R.N.; Cooper, M.; Chen, C.T.

    1992-07-01

    This document is the annual progress report for project entitled ``Instrumentation and Quantitative Methods of Evaluation.`` Progress is reported in separate sections individually abstracted and indexed for the database. Subject areas reported include theoretical studies of imaging systems and methods, hardware developments, quantitative methods of evaluation, and knowledge transfer: education in quantitative nuclear medicine imaging.