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. Quantitative nondestructive evaluation of materials and structures

    NASA Technical Reports Server (NTRS)

    Smith, Barry T.

    1991-01-01

    An experimental investigation was undertaken to quantify damage tolerance and resistance in composite materials impacted using the drop-weight method. Tests were conducted on laminates of several different carbon-fiber composite systems, such as epoxies, modified epoxies, and amorphous and semicrystalline thermoplastics. Impacted composite specimens were examined using destructive and non-destructive techniques to establish the characteristic damage states. Specifically, optical microscopy, ultrasonic, and scanning electron microscopy techniques were used to identify impact induced damage mechanisms. Damage propagation during post impact compression was also studied.

  3. Towards quantitative non-destructive evaluation of aging aircraft

    NASA Astrophysics Data System (ADS)

    Achenbach, J. D.; Thompson, D. O.

    Nondestructive testing techniques, as they are practiced in the field of quantitative nondestructive evaluation, are at the basis of a comprehensive approach to secure the safety of aging aircraft. The applications, advantages and disadvantages of the principal NDE techniques are summarized in this paper. It is discussed that measurement models for these techniques, in conjunction with the probability of detection concept, scanning plans, and methods of graphical display, facilitate the selection of optimal procedures for specific inspection problems. These models also suggest NDE standards and calibration techniques, and they can be an important part of inspection system validation and operator training. Four major components of a comprehensive quantitative NDE program for aging aircraft are identified and briefly discussed.

  4. The Nuclear Renaissance - Implications on Quantitative Nondestructive Evaluations

    SciTech Connect

    Matzie, Regis A. [Westinghouse Electric Company, 20 International Drive, Windsor, CT 06095 (United States)

    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.

  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. Advanced quantitative magnetic nondestructive evaluation methods - Theory and experiment

    NASA Technical Reports Server (NTRS)

    Barton, J. R.; Kusenberger, F. N.; Beissner, R. E.; Matzkanin, G. A.

    1979-01-01

    The paper reviews the scale of fatigue crack phenomena in relation to the size detection capabilities of nondestructive evaluation methods. An assessment of several features of fatigue in relation to the inspection of ball and roller bearings suggested the use of magnetic methods; magnetic domain phenomena including the interaction of domains and inclusions, and the influence of stress and magnetic field on domains are discussed. Experimental results indicate that simplified calculations can be used to predict many features of these results; the data predicted by analytic models which use finite element computer analysis predictions do not agree with respect to certain features. Experimental analyses obtained on rod-type fatigue specimens which show experimental magnetic measurements in relation to the crack opening displacement and volume and crack depth should provide methods for improved crack characterization in relation to fracture mechanics and life prediction.

  7. Nondestructive Quantitative Evaluation of Porosity Volume Distribution in Aluminum Alloy Die Castings by Fractal Analysis

    Microsoft Academic Search

    Yoshihiko Hangai; Shota Maruhashi; Soichiro Kitahara; Osamu Kuwazuru; Nobuhiro Yoshikawa

    2009-01-01

    The nondestructive and three-dimensional quantitative evaluation of porosity in aluminum alloy die castings is proposed to\\u000a identify whether the predominant cause of pore formation is shrinkage or entrapped gas. The validity of this method of evaluation\\u000a was shown by comparing two different regions with different ratios of pores formed by shrinkage and gas. It was shown that\\u000a the proposed evaluation

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

    NASA Technical Reports Server (NTRS)

    Miller, J. G.

    1986-01-01

    The application and interpretation of specific ultrasonic nondestructive evaluation techniques are studied. The Kramers-Kronig or generalized dispersion relationships are applied to nondestructive techniques. Progress was made on an improved determination of material properties of composites inferred from elastic constant measurements.

  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. 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.

  11. 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.

  12. 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.

  13. 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.

  14. [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)

  15. 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.

  16. Nondestructive and quantitative evaluation of wire rope based on radial basis function neural network using eddy current inspection

    Microsoft Academic Search

    Qingsong Cao; Dan Liu; Yuehai He; Jihui Zhou; John Codrington

    Wire ropes have been widely used in elevators, lifting machinery, passenger aerial ropeways, and other related fields. Such ropes often deteriorate during their lifetime due to external or internal corrosion and abrasion, and dynamic mechanical stresses. Nondestructive evaluation methods are being increasingly applied to monitor wire ropes. In this paper, an adjustable, annular testing device, consisting of probes arranged in

  17. 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.

  18. Evaluation of nondestructive tensile testing

    NASA Technical Reports Server (NTRS)

    Bowe, J. J.; Polcari, S. M.

    1971-01-01

    The results of a series of experiments performed in the evaluation of nondestructive tensile testing of chip and wire bonds are presented. Semiconductor devices were subjected to time-temperature excursions, static-load life testing and multiple pre-stressing loads to determine the feasibility of a nondestructive tensile testing approach. The report emphasizes the importance of the breaking angle in determining the ultimate tensile strength of a wire bond, a factor not generally recognized nor implemented in such determinations.

  19. 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.

  20. 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.

  1. 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.

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

    SciTech Connect

    Yan, Yong [ORNL; Qian, Shuo [ORNL; Littrell, Ken [ORNL; Parish, Chad M [ORNL; Plummer, Lee K [ORNL

    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.

  3. 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.

  4. Quantitative nondestructive evaluation of adhesive lap joints in sheet molding compound by adaptation of a commercial bond tester

    NASA Astrophysics Data System (ADS)

    Papadakis, Emmanual P.; Chapman, Gilbert B., II

    The paper presents a method for obtaining quantitative NDE measurements from a commercial adhesive bond tester designed for GO/NO-GO qualitative sorting. With the proper reference specimens and the quantitative output, the instrument can be used to make measurements which correlate with adhesive bond strength. With the reference specimens and the built-in alarm mode of the instrument, measurements can be made to define a probability of detection (POD) for disbonds vs disbond size. With this POD, a specification for an adhesive lap joint in terms of an acceptable percentage of bonded area is defined. The bond tester makes it possible to expand application of adhesively bonded SMC body panels.

  5. 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.

  6. Quantitative Nondestructive Evaluation of the Crack on the Austenite Stainless Steel Using the Induced Eddy Current and the Hall Sensor Array

    Microsoft Academic Search

    Jongwoo Jun; Jiseong Hwang; Jinyi Lee

    2007-01-01

    Nondestructive evaluation (NDE) has been effective in the prediction and evaluation of cracks on the surface of structures. Austenite stainless steel such as SUS304 and SUS316 is a paramagnetic metal with delta -ferrite structure. Small amount of partial magnetization is generated in the austenite stainless steel due to the final heat treatment and the mechanical working. The MOI (magneto-optical\\/eddy current

  7. 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.

  8. NONDESTRUCTIVE EVALUATION (NDE) OF DAMAGED STRUCTURAL CERAMICS

    SciTech Connect

    Brennan, R. E.; Green, W. H.; Sands, J. M.; Yu, J. H. [US Army Research Laboratory, 4600 Deer Creek Loop, Aberdeen Proving Ground, MD 21005-5066 (United States)

    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.

  9. Nondestructive Evaluation (nde) of Damaged Structural Ceramics

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

    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.

  10. Nondestructive evaluation with laser ultrasound

    SciTech Connect

    Ashley, S.

    1994-10-01

    This article describes how laser-based systems generate and detect ultrasonic waves from a distance for on-line process control and rapid NDE inspection. Not long after the laser was invented in the 1960s, scientists proposed using the powerful new optical device for a novel nondestructive examination (NDE) technique that could probe the interior of an object from a distance. A short, intense laser pulse, they suggested, could non-destructively ''whack'' the surface of a test article by rapidly heating a small target area. The spot would thermally expand nearly instantaneously and send ultrasonic waves through the material. When these acoustic waves hit the boundaries of the test object or any internal flaws or discontinuities, they would rebound elastically and produce minute surface vibrations at the target area. This target would then be illuminated by a second detection laser, whose light is scattered by the surface. Ultrasonic motion at the surface causes a small phase or frequency shift (Doppler effect) in the scattered laster light, which is detected by an interferometer--a precision instrument that uses interference fringe phenomena to measure small displacements and their velocities. When the resulting interference patterns are analyzed to determine the frequency content of the tiny surface perturbations, the test item's dimensions, defect content, and even its physical state of matter can be determined.

  11. 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.

  12. Overview of acoustical technology for nondestructive evaluation

    Microsoft Academic Search

    Robert E. Green Jr.

    1992-01-01

    A brief overview is presented of acoustical techniques for nondestructive evaluation of materials and structures. Among the general topics covered are modes of elastic wave propagation in solid materials, energy flux vector, and nonlinear effects. Included in the section on ultrasonic measurements are ultrasonic attenuation, laser ultrasonics, full-field imaging of acoustic displacements, optical detection of acoustic emission, acousto-ultrasonics, acoustic microscopy,

  13. SQUIDs: microscopes and nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Mück, Michael

    2005-03-01

    SQUIDs (Superconducting Quantum Interference Devices) are magnetic field sensores with unsurpassed sensitivity. They are amazingly versatile, being able to measure all physical quantities which can be converted to magnetic flux. They are routinely fabricated in thin film technology from two classes of superconducting materials: high-temperature superconductors (HTS) which are usually cooled to 77 K, and low-temperature superconductors (LTS), which have to be cooled to 4.2 K. SQUIDs have many applications, two of which shall be discussed in this paper. In SQUID microscopy, a SQUID scans a sample, which preferrably is at room temperature, and measures the two-dimensional magnetic field distribution at the surface of the sample. In order to achieve a relatively high spatial resolution, the stand-off distance between the sample and the SQUID is made as small as possible. SQUIDs show also promising results in the field of nondestructive testing of various materials. For example, ferromagnetic impurities in stainless steel formed by aging processes in the material can be detected with high probability, and cracks in conducting materials, for example aircraft parts, can be located using eddy current methods. Especially for the case of thick, highly conductive, or ferromagnetic materials, as well as sintered materials, it can be shown that a SQUID-based NDE system exhibits a much higher sensitivity compared to conventional eddy current NDE and ultrasonic testing.

  14. 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.

  15. Ultrasonic nondestructive evaluation of armor ceramics

    NASA Astrophysics Data System (ADS)

    Brennan, Raymond Edwin, IV

    Ceramic materials have been incorporated into armor systems to reduce their weight while providing high hardness, strength, and elastic response to stress. However, the presence of defects and flaws in armor ceramics can lead to ballistic failure. Nondestructive evaluation (NDE) techniques have been studied to locate and characterize defects and inhomogeneities in these materials. High frequency ultrasound NDE has been explored for detecting and locating micron-range defects and identifying microstructural changes in dense armor ceramics such as silicon carbide (SiC). Ultrasound parameters such as transducer frequency have been analyzed to determine system conditions necessary for obtaining C-scan image maps based on differences in intensity of the collected ultrasound signals (reflected signal amplitudes) or transit time of ultrasound energy through materials (time-of-flight TOF). While TOF has have been used to evaluate changes in thickness, velocity, density, and acoustic impedance, reflected signal amplitude has been used to analyze attenuation, or loss, through a test specimen. Reflected signal amplitude and TOF C-scan imaging have been useful for identifying and locating isolated defects and microstructural differences. Elastic property maps have been developed to plot differences in Poisson's ratio, elastic modulus, shear modulus, and bulk modulus. Quantitative analysis techniques have been used to evaluate cumulative effects of reflected signal amplitude and TOF changes over scanned regions and their distributions over selected areas. Amplitude and TOF histogram curves, which have been characterized by area-under-the-curve values, full-width at half-maximum values, and critical tail regions, have provided a valuable means of sample comparison. Generally, more narrow distributions of amplitude and TOF values have corresponded to high density armor-grade samples, while broad distributions have indicated defects or inhomogeneous regions in the samples. In addition to developing techniques for determining individual defect size distributions within a bulk specimen, histogram simulations have been explored to study amplitude and TOF distribution trends by analyzing how the addition of defects of varying size, quantity, and acoustic impedance affect histogram characteristics. These data have been utilized to establish a representative materials fingerprint that provides defect input data which can be further quantified and applied to property, design, and performance modeling of armor ceramic materials.

  16. 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.

  17. Non-destructive assessment of human ribs mechanical properties using quantitative ultrasound.

    PubMed

    Mitton, David; Minonzio, Jean-Gabriel; Talmant, Maryline; Ellouz, Rafaa; Rongieras, Frédéric; Laugier, Pascal; Bruyère-Garnier, Karine

    2014-04-11

    Advanced finite element models of the thorax have been developed to study, for example, the effects of car crashes. While there is a need for material properties to parameterize such models, specific properties are largely missing. Non-destructive techniques applicable in vivo would, therefore, be of interest to support further development of thorax models. The only non-destructive technique available today to derive rib bone properties would be based on quantitative computed tomography that measures bone mineral density. However, this approach is limited by the radiation dose. Bidirectional ultrasound axial transmission was developed on long bones ex vivo and used to assess in vivo health status of the radius. However, it is currently unknown if the ribs are good candidates for such a measurement. Therefore, the goal of this study is to evaluate the relationship between ex vivo ultrasonic measurements (axial transmission) and the mechanical properties of human ribs to determine if the mechanical properties of the ribs can be quantified non-destructively. The results show statistically significant relationships between the ultrasonic measurements and mechanical properties of the ribs. These results are promising with respect to a non-destructive and non-ionizing assessment of rib mechanical properties. This ex vivo study is a first step toward in vivo studies to derive subject-specific rib properties. PMID:24581799

  18. 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.

  19. Nondestructive evaluation of nuclear-grade graphite

    NASA Astrophysics Data System (ADS)

    Kunerth, D. C.; McJunkin, T. R.

    2012-05-01

    The material of choice for the core of the high-temperature gas-cooled reactors being developed by the U.S. Department of Energy's Next Generation Nuclear Plant Program is graphite. Graphite is a composite material whose properties are highly dependent on the base material and manufacturing methods. In addition to the material variations intrinsic to the manufacturing process, graphite will also undergo changes in material properties resulting from radiation damage and possible oxidation within the reactor. Idaho National Laboratory is presently evaluating the viability of conventional nondestructive evaluation techniques to characterize the material variations inherent to manufacturing and in-service degradation. Approaches of interest include x-ray radiography, eddy currents, and ultrasonics.

  20. Nondestructive evaluation of nuclear-grade graphite

    SciTech Connect

    Kunerth, D. C.; McJunkin, T. R. [Idaho National Laboratory, P.O. Box 1625, MS 2209, Idaho Falls, ID 83415-2209 (United States)

    2012-05-17

    The material of choice for the core of the high-temperature gas-cooled reactors being developed by the U.S. Department of Energy's Next Generation Nuclear Plant Program is graphite. Graphite is a composite material whose properties are highly dependent on the base material and manufacturing methods. In addition to the material variations intrinsic to the manufacturing process, graphite will also undergo changes in material properties resulting from radiation damage and possible oxidation within the reactor. Idaho National Laboratory is presently evaluating the viability of conventional nondestructive evaluation techniques to characterize the material variations inherent to manufacturing and in-service degradation. Approaches of interest include x-ray radiography, eddy currents, and ultrasonics.

  1. EPRI nondestructive evaluation center: technology transfer to improve reliability

    Microsoft Academic Search

    T. A. Nemzek; P. L. Schoenecke; G. W. Wickliffe

    1985-01-01

    The development and improvement of nondestructive evaluation methods used by the electric utility industry for in-service inspection (ISI) is a priority program of the Electric Power Research Institute (EPRI). The institute established the EPRI Nondestructive Evaluation (NDE) Center in Charlotte, North Carolina. The NDE Center, completed in February 1981, is operated for EPRI by J.A. Jones Applied Research Company and

  2. 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.

  3. 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.

  4. 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.

  5. SHEAROGRAPHY AND APPLICATIONS IN NONDESTRUCTIVE EVALUATION

    Microsoft Academic Search

    Michael Y. Y. Hung

    This article reviews shearography and its applications in nondestructive testing. Shearography is a laser-based technique for full-field and non-contacting measurement of surface deformation (displacement or strains). Despite being a relative young technique, it has already received considerable industrial acceptance, in particular, for nondestructive testing. One major difference of shearography from other NDT techniques is the mechanics of revealing flaws. Shearography

  6. A new technique for ultrasonic nondestructive evaluation of adhesive joints 

    E-print Network

    Hanneman, Susan Elisabeth

    1991-01-01

    A NEW TECHNIQUE FOR ULTRASONIC NONDESTRUCTIVE EVALUATION OF ADHESIVE JOINTS A Thesis by SUSAN ELISABETH HANNEMAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 1991 Major Subject: Aerospace Engineering A NEW TECHNIQUE FOR ULTRASONIC NONDESTRUCTIVE EVALUATION OF ADHESIVE JOINTS A Thesis by SUSAN ELISABETH HANNEMAN Approved as to style and content by: Vikram K. Kinra (Chair...

  7. 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

  8. Non-destructive evaluation and quality control of surface treatments

    NASA Astrophysics Data System (ADS)

    Rideout, Curtis A.; Ritchie, Scott J.

    2007-04-01

    The ability to detect and quantify beneficial surface and subsurface residual stresses, and operational damage in aerospace materials/structures in a reliable and efficient manner presents significant challenges to existing nondestructive inspection technologies. Induced Positron Analysis (IPA) has demonstrated the ability to nondestructively quantify shot peening/surface treatments and relaxation effects in single crystal superalloys, steels, titanium and aluminum with a single measurement as part of a National Science Foundation SBIR program and in projects with commercial companies. IPA measurement of surface treatment effects provides a demonstrated ability to quantitatively measure initial treatment effectiveness along with the effect of operationally induced changes over the life of the treated component. Use of IPA to nondestructively quantify surface and subsurface residual stresses in turbine engine materials and components has the potential to significantly improve the understanding at the microscale level the effects of surface coatings and treatments on the durability and fatigue life of critical components.

  9. Nondestructive inspection and evaluation of composite-material flywheels

    SciTech Connect

    Reifsnider, K.L.; Boyd, D.M.; Kulkarni, S.V.

    1982-02-24

    It has been demonstrated that flywheels made from composite materials are capable of storing energy with a significantly higher energy density than those made from conventional metals. Since composite materials are also very durable and inherently safer for such applications, it would appear that they will play a major role in flywheel energy-storage systems. This report addresses the question of how flywheels made from composite materials can be inspected with nondestructive test methods to establish their initial quality and their subsequent integrity during service. A variety of methods is discussed in the context of special requirements for the examination of composite flywheel structures and the results of several example nondestructive evaluations before and after spin testing are presented. Recommendations for general nondestructive testing and evaluation of composite-material flywheels are made.

  10. 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.

  11. A review of SQUID magnetometry applied to nondestructive evaluation

    Microsoft Academic Search

    Harold Weinstock; Bolling AFB

    1991-01-01

    The development of the SQUID as the most sensitive instrument known for the measurement of changes in magnetic flux has presented new opportunities for its use for nondestructive evaluation (NDE) of electrically conducting and ferromagnetic structures. The preliminary studies of this application within the past few years are reviewed in order to serve as an introduction to those that follow.

  12. Nondestructive Evaluation of Ni-Ti Shape Memory Alloy

    Microsoft Academic Search

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

    2011-01-01

    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

  13. 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...

  14. Nondestructive evaluation of thick-composite fatigue damage

    Microsoft Academic Search

    Robert E. Green

    1995-01-01

    This paper describes the results of the comparison of a variety of nondestructive evaluation techniques to monitor the development of fatigue damage in thick graphite\\/epoxy composites. Three inch long, one inch square cross-section test specimens were fatigue tested in compression. Most specimens incorporated stress (strain) concentration notches at their mid- section in order to localize the primary fatigue damage regions

  15. Embedded Non-destructive Evaluation for Structural Health Monitoring, Damage Detection, and Failure

    E-print Network

    Giurgiutiu, Victor

    Articles Embedded Non-destructive Evaluation for Structural Health Monitoring, Damage Detection, diagnosis, prog- nosis, mixed-mode fracture, non-destructive evaluation, non- destructive inspection 1; Butterworth-Hayes, 2003; Talbot, 2003; Staszewski et al., 2004) 1.1. Conventional Non-destructive Evaluation

  16. 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.

  17. Nondestructive evaluation of turbines and generators: 1980 conference and workshop

    SciTech Connect

    Richman, R.H.; Rettig, T. (eds.)

    1981-07-01

    This report contains formal presentations and results of four workshop sessions on the nondestructive evaluation (NDE) of steam turbines and generators. The workshop was directed at utility problems in turbine-generator evaluation and in making repair or run-retire decisions. Areas of concentration include (1) industry problems, (2) turbine NDE, (3) generator NDE, (4) EPRI projects, (5) vibration signature analysis, and (6) new developments. Separate abstracts were prepared for 29 of the papers.

  18. Quantitative non-destructive environmental characterization of advanced materials

    SciTech Connect

    Dobie, D.; Celeste, J.; Krauter, G.

    1991-12-31

    Polymethylpentene, polystyrene, agar, carbon, and composites, are advanced materials that have unique engineering properties. Of particular interest to our engineering department is their response to temperature and humidity excursions. We built computer-controlled environmental test chambers to evaluate the materials and derive thermal and hygroscopic (water absorption) properties.

  19. 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.

  20. Aging management of major LWR components with nondestructive evaluation

    SciTech Connect

    Shah, V.N.; MacDonald, P.E.; Akers, D.W.; Sellers, C. [Idaho National Engineering and Environmental Lab., Idaho Falls, ID (United States); Murty, K.L.; Miraglia, P.Q.; Mathew, M.D. [North Carolina State Univ., Raleigh, NC (United States); Haggag, F.M. [Advanced Technology Corp. (United States)

    1997-12-31

    Nondestructive evaluation of material damage can contribute to continued safe, reliable, and economical operation of nuclear power plants through their current and renewed license period. The aging mechanisms active in the major light water reactor components are radiation embrittlement, thermal aging, stress corrosion cracking, flow-accelerated corrosion, and fatigue, which reduce fracture toughness, structural strength, or fatigue resistance of the components and challenge structural integrity of the pressure boundary. This paper reviews four nondestructive evaluation methods with the potential for in situ assessment of damage caused by these mechanisms: stress-strain microprobe for determining mechanical properties of reactor pressure vessel and cast stainless materials, magnetic methods for estimating thermal aging damage in cast stainless steel, positron annihilation measurements for estimating early fatigue damage in reactor coolant system piping, and ultrasonic guided wave technique for detecting cracks and wall thinning in tubes and pipes and corrosion damage to embedded portion of metal containments.

  1. Development of SQUID-Based System for Nondestructive Evaluation

    Microsoft Academic Search

    R. Nagendran; M. P. Janawadkar; M. Pattabiraman; J. Jayapandian; R. Baskaran; L. S. Vaidhyanathan; Y. Hariharan; A. Nagesha; M. Valsan; K. B. S. Rao; B. Raj

    2007-01-01

    This article describes the development of a superconducting quantum interference device (SQUID)-based system for nondestructive evaluation. The setup incorporates an in-house developed thin-film-based Nb SQUID with readout flux locked loop electronics and consists of a liquid helium cryostat with adjustable stand-off distance, a precision XY- thetas scanner for studying both flat and cylindrical samples, and a data acquisition system. The

  2. 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.

  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. 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.

  5. 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.

  6. Nondestructive evaluation of Ni-Ti shape memory alloy

    SciTech Connect

    Meir, S.; Gordon, S.; Karsh, M.; Ayers, R.; Olson, D. L. [Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO (United States); Wiezman, A. [Netania (Israel)

    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.

  7. 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.

  8. Microwave nondestructive evaluation: State-of-the-Art review

    NASA Astrophysics Data System (ADS)

    Zoughi, R.; Ganchev, S.

    1995-02-01

    This State-of-the-Art Review contains information on both the fundamental science and general applications of microwave nondestructive evaluation. Chapter contents include: introductory background on microwave and millimeter wave spectra, definition and scope of microwave NDE, dielectric properties of materials, material characterization using microwaves, thickness and disbond measurements, microwave techniques for surface cracks, defect detection in thick composites, and concluding remarks and the future of microwave NDE. The publication contains 553 references to microwave NDE-related papers in the public literature.

  9. PRESSURE BAG MOLDING: MANUFACTURING, MECHANICAL TESTING, NON-DESTRUCTIVE EVALUATION, AND ANALYSIS

    E-print Network

    -up ..............................................................................................................13 Resin Transfer Molding.............................................................................................14 Vacuum Assisted Resin Transfer MoldingPRESSURE BAG MOLDING: MANUFACTURING, MECHANICAL TESTING, NON-DESTRUCTIVE EVALUATION, AND ANALYSIS

  10. 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.

  11. Symposium on Nondestructive Evaluation, 15th, San Antonio, TX, April 23-25, 1985, Proceedings

    SciTech Connect

    Matzkanin, G.A.; Moore, D.W.

    1986-01-01

    Papers presented include the application of the electric current perturbation method to the inspection of magnetic materials, the acoustical holographic Siamese image technique for imaging radial cracks in reactor piping, advanced enhancement techniques for digitized images, ultrasonic inspection systems for sonar dome rubber windows, and a novel acoustic coupling device using permeable membranes. Consideration is given to a dry imaging system for radiography, the role of laser technology in materials processing and NDT in the 21st century, a computer controlled array of ultrasonic transducers for the fast inspection of steel pipes, quantitative ultrasonic NDE, and the effect of tensile straining on the magnetic pulses induced during cyclic loading of a ferromagnetic steel. In addition, use of ultrasonics for quantitative nondestructive evaluation, imaging of defects in fiber-reinforced composites, and for determination of principal stress differences in a slightly anisotropic residual stress specimen are discussed.

  12. Nerva fuel nondestructive evaluation and characterization equipment and facilities

    SciTech Connect

    Caputo, A.J. (Martin Marietta Energy Systems, Inc., Oak Ridge, Y-12 Plant Oak Ridge, TN 37831 (United States))

    1993-01-20

    Nuclear Thermal Propulsion (NTP) is one of the technologies that the Space Exploration Initiative (SEI) has identified as essential for a manned mission to Mars. A base or prior work is available upon which to build in the development of nuclear rockets. From 1955 to 1973, the U.S Atomic Energy Commission (AEC) sponsored development and testing of a nuclear rocket engine under Project Rover. The rocket engine, called the Nuclear Engine for Rocket Vehicle Application (NERVA), used a graphite fuel element incorporating coated particle fuel. Much of the NERVA development and manufacturing work was performed at the Oak Ridge Y[minus]12 Plant. This paper gives a general review of that work in the area of nondestructive evaluation and characterization. Emphasis is placed on two key characteristics: uranium content and distribution and thickness profile of metal carbide coatings deposited in the gas passage holes.

  13. Millimeter-wave imaging for nondestructive evaluation of materials

    SciTech Connect

    Gopalsami, N; Bakhtiari, S.; Dieckman, S.L.; Raptis, A.C.; Lepper, M.J. (Argonne National Lab., IL (United States). 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.

  14. Infrared non-destructive evaluation method and apparatus

    SciTech Connect

    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.

  15. 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.

  16. 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.

  17. 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.

  18. Resonant ultrasound spectroscopy (RUS) is a non-destructive technique originally developed for evaluating

    E-print Network

    RUS Resonant ultrasound spectroscopy (RUS) is a non- destructive technique originally developed of vibration observed in samples with regular geometry. RUS can also be used for non-destructive evaluation measurement results. Resonant ultrasound spectroscopy (RUS) is a non-destructive material characterisation

  19. 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

  20. 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

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

    SciTech Connect

    Clayton, Dwight; Smith, Cyrus [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States)

    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.

  2. 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.

  3. Low-frequency electromagnetic technique for nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Dalichaouch, Yacine; Singsaas, Alan L.; Putris, Firas; Perry, Alexander R.; Czipott, Peter V.

    2000-05-01

    We have developed a low frequency electromagnetic technique using sensitive room temperature magnetoresistive (MR) sensors for a variety of nondestructive evaluation (NDE) applications. These applications include the NDE of medical implants and aircraft structures, the detection of cracks and corrosion in metals, the detection of ferromagnetic foreign objects in the eye and the brain, and the noninvasive determination of iron content in the liver. Our technique consists of applying a low frequency ac magnetic field to the sample and detecting the sample response. The low excitation frequency enables us to probe deep into metal structures; the sensitivity of the MR sensor allows us to detect weak responses from the sample without applying too large an excitation field, particularly in the case of human tissue. The MR sensors are small and relatively inexpensive compared to other sensitive magnetic field sensors such as fluxgates and superconducting quantum interference devices or SQUIDs; hence the resulting NDE instrument will be compact and cost-efficient, enabling its commercialization for practical applications. In this paper, we focus primarily on NDE of orthopedic implants.

  4. 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.

  5. Development of nondestructive evaluation methods for structural ceramics

    SciTech Connect

    Ellingson, W.A.; Koehl, R.D.; Wilson, J.A.; Stuckey, J.B. [Argonne National Lab., IL (United States). Energy Technology Div.; Engel, H.P. [Argonne National Lab., IL (United States). Energy Technology Div.; [Heaviside Science, Inc., Melbourne, FL (United States)

    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.

  6. 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.

  7. 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).

  8. Assessment of FRP-confined concrete : understanding behavior and issues in nondestructive evaluation using radar

    E-print Network

    Ortega, Jose Alberto, 1978-

    2006-01-01

    Increase in the use of fiber-reinforced polymer (FRP) composite materials for strengthening and retrofitting of concrete columns and bridge piers has urged the development of' an effective non-destructive evaluation (NDE) ...

  9. Ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials

    E-print Network

    Wang, Ji-yong, 1967-

    2003-01-01

    Characterization of defect is one of the important objectives of nondestructive evaluation (NDE) for condition assessment of structures. Among many other NDE techniques, ultrasonic methods play a prominent role in the both ...

  10. Non-Destructive Evaluation of Bridge Stay Cable and External Post-Tensioning Systems 

    E-print Network

    McCoy, Katlyn Mae

    2014-10-09

    Non-destructive evaluation (NDE) of bridge stay cable and external post-tensioning (PT) systems is an essential tool to thorough bridge inspections and also eliminates any necessary repair of destructions made during ...

  11. Paper #1547 Presented at the International Congress on Ultrasonics, Vienna, April 9 -13, 2007, Session S04: Non-destructive evaluation of anisotropic materials

    E-print Network

    Paris-Sud XI, Université de

    , Session S04: Non-destructive evaluation of anisotropic materials - 1 - Non-destructive diagnosis transducers, and a numerical system and computing and recording the projections. When performing non-destructive

  12. Nondestructive damage detection and evaluation technique for seismically damaged structures

    NASA Astrophysics Data System (ADS)

    Adachi, Yukio; Unjoh, Shigeki; Kondoh, Masuo; Ohsumi, Michio

    1999-02-01

    The development of quantitative damage detection and evaluation technique, and damage detection technique for invisible damages of structures are required according to the lessons from the 1995 Hyogo-ken Nanbu earthquake. In this study, two quantitative damage sensing techniques for highway bridge structures are proposed. One method is to measure the change of vibration characteristics of the bridge structure. According to the damage detection test for damaged bridge column by shaking table test, this method can successfully detect the vibration characteristic change caused by damage progress due to increment excitations. The other method is to use self-diagnosis intelligent materials. According to the reinforced concrete beam specimen test, the second method can detect the damage by rupture of intelligent sensors, such as optical fiber or carbon fiber reinforced plastic rod.

  13. 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.

  14. 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.

  15. 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 ?2 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.

  16. 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.

  17. 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.

  18. Nondestructive quantitative synchrotron grazing incidence x-ray scattering analysis of cylindrical nanostructures in supported thin films.

    SciTech Connect

    Yoon, J.; Yang, S. Y.; Lee, B.; Joo, W.; Heo, K.; Kim, J. K.; Ree, M.; X-Ray Science Division; Pohang Univ. of Science and Technology

    2007-01-01

    Nondestructive nanostructural analysis is indispensable in the development of nanomaterials and nanofabrication processes for use in nanotechnology applications. This paper demonstrates a quantitative, nondestructive analysis of nanostructured thin films supported on substrates and their templated nanopores by using grazing incidence X-ray scattering and data analysis with a derived scattering theory. The analysis disclosed that vertically oriented nanodomain cylinders had formed in 20-100 nm thick films supported on substrates, which consisted of a mixture of poly(styrene-b-methyl methacrylate) (PS-b-PMMA) and PMMA homopolymer, and that the PMMA nanodomain cylinders were selectively etched out by ultraviolet light exposure and a subsequent rinse with acetic acid, resulting in a well ordered nanostructure consisting of hexagonally packed cylindrical nanopores.

  19. Application of Internal Friction Damping as a Nondestructive Evaluation Technique for Wire Rope

    Microsoft Academic Search

    A. Hochrein Jr; A. Thiruvengadam; J. Sherrard

    1983-01-01

    This paper discusses the technical feasibility of applying internal friction damping (IFD) as a nondestructive evaluation (NDE) technique to wire rope. The paper addresses the technical feasibility, laboratory testing on wire rope, and the associated test results on various samples of wire rope. These tests were evaluated in a series of laboratory experiments by measuring the internal friction damping during

  20. Application of internal friction nondestructive evaluation technique for wire ropes used in mining operations

    Microsoft Academic Search

    L. Olver; R. G. Brasfield; L. L. Yeager; A. P. Thiruvengadam

    1980-01-01

    This report discusses the work done, and results obtained, in a program conducted to determine the feasibility of applying the Internal Friction Damping - Nondestructive Evaluation (IFD-NDE) technique to wire rope. Samples of wire rope were evaluated in laboratory experiments by measuring the internal friction damping while varying several test parameters. These parameters included tensile load, frequency of test, time

  1. 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.

  2. 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. (AMNH)

    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.

  3. Cyclic deformation, fracture, and nondestructive evaluation of advanced materials

    SciTech Connect

    Mitchell, M.R.; Buck, O.

    1992-01-01

    Papers are presented on cyclic fatigue of alumnia, fatigue crack growth in ceramics and ceramic-matrix composites, fatigue test methodology and results for ceramic matrix composites at room and elevated temperatures, and modeling crack growth resistance in ceramics and ceramic-matrix composites. Attention is also given to thermomechanical cyclic deformation of metal-matrix composites, the effect of tensile mean stress on the fatigue behavior of single-crystal and directionally solidified superalloys, the influence of constituent properties on the compression behavior of aluminates with discontinuities, and cyclic creep effects in single-overlap bonded joints under constant-amplitude testing. Other papers discuss an ultrasonic wave technique to assess cyclic-load fatigue damage in silicon-carbide whisker-reinforced 2124 aluminum alloy composites, nondestructive characterization for metal-matrix composite fabrication, NDE of a ceramic matrix composite material, and split spectrum processing of backscattered Rayleigh wave signals to improve detectability of fatigue microcracks.

  4. Nondestructive evaluation of load transfer at rigid airport pavement joints

    NASA Astrophysics Data System (ADS)

    Hammons, Michael I.

    1995-07-01

    Current design criteria for rigid pavements for commercial and military airfields assume that 25% of the load applied to an edge of a slab is transferred through the joint to an adjacent unloaded slab. A nondestructive testing technique using a falling weight deflectometer (FWD) was used to conduct field testing at a number of sites. A transfer function, developed from an analytical study, was used to estimate load transfer from the measured joint efficiency as a function of the loaded area and the radius of relative stiffness of the pavement. This procedure, although analytically sound, lacks actual field verification at an instrumented pavement site. This procedure was used to estimate load transfer at a number of commercial and military airfields for a variety of joint types, climate conditions, and pavement structures. The results of these tests indicate that the assumption of load transfer as a constant value of 25% appears to be unconservative, especially during the winter months.

  5. Residual stress measurement of refractory coatings as a nondestructive evaluation

    SciTech Connect

    Chollet, L.; Boving, H.; Hintermann, H.E.

    1985-03-01

    Due to their good resistance to wear and corrosion, TiC refractory coatings are increasingly applied in certain domains of the nuclear and aerospace industries. Quality control of materials being usually destructive, residual-stress measurements are suggested as a means of a nondestructive quality control. Based on the classical sin/sup 2//PSI/ method, residual stresses are measured for TiC coatings on cemented carbides and steel substrates. Medium tensile residual stresses are obtained in TiC on cemented carbide substrates, while rather large compressive residual stresses appear on steel substrates. A phenomenological interpretation of these stresses is given. The experimental results disprove the generally assumed two-dimensional stress system, confirming thus the existence of stress gradients in the third dimension, and of a threedimensional stress system in the volume sampled by the X-ray beams.

  6. Compensation electronics for larger dynamic range of a SQUID based nondestructive evaluation system

    Microsoft Academic Search

    M. V. Kreutzbruck; A. Theiss; M. Mück; C. Heiden

    1999-01-01

    We have developed a compensation system for any given SQUID sensor which allows sensitive eddy current measurements above 100 Hz in the presence of strong and slowly varying background fields. High Tc SQUIDs have been used successfully in nondestructive evaluation (NDE) systems based on eddy current excitation when searching for defects in conductive samples such as aircraft parts. Due to

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

    Microsoft Academic Search

    James Ronald Claycomb

    1998-01-01

    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

  8. DIVISION & TECHNICAL COMMITTEE MEMBERSHIP: -Division Chair of the ASME NDE (Nondestructive Evaluation) Division, 2003-2005

    E-print Network

    Wong, Pak Kin

    DIVISION & TECHNICAL COMMITTEE MEMBERSHIP: - Division Chair of the ASME NDE (Nondestructive Evaluation) Division, 2003-2005 - Member of the Executive Committee of the ASME NDE Engineering Division, 1997-present - Secretary and Vice-Chairman of the ASME NDE Division from 2001 to 2003 - Program

  9. 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...

  10. Hertzian contact transducers for nondestructive evaluation F. L. Degertekin and B. T. Khuri-Yakub

    E-print Network

    Khuri-Yakub, Butrus T. "Pierre"

    H transducer and a quartz buffer rod is realized for this purpose. In particular, the lowest orderHertzian contact transducers for nondestructive evaluation F. L. Degertekin and B. T. Khuri to plate wave modes in anisotropic solid plates. A new transducer configuration using a piezoelectric PZT-5

  11. Microwave nondestructive detection and evaluation of voids in layered dielectric slabs

    Microsoft Academic Search

    R. Zoughi; S. Bakhtiari

    1990-01-01

    A microwave nondestructive testing technique is discussed for detection and evaluation of voids in layered dielectric media backed by a conducting plate. This technique utilizes the phase properties of the effective reflection coefficient of the medium as a microwave signal penetrates inside the dielectric layers and is reflected by the conducting plate. Properties of the difference between this phase in

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

    Microsoft Academic Search

    Ed Generazio

    2006-01-01

    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

  13. 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.

  14. Research progress of non-destructive evaluation used in wood structure

    Microsoft Academic Search

    Jin Zhang; Ya-chao Wang; Xiao-jing Yang; Shu-wei Ma; Qing-feng Xu; Xiang-min Li

    2011-01-01

    Non-destructive evaluation (NDE) is an effective and reasonable technology for utilization in wooden material. Facing the defects of wooden material, the effective NDE appears practically significant for protecting wood structures. Major NDE techniques and equipments applied in wood structures detection were systematically summarized. Then State of main researches on NDE used in wooden material was reviewed, including the imaging technique,

  15. On-line nondestructive evaluation of carbon content of steel using surface temperature during induction heating

    Microsoft Academic Search

    Sun Yafei; Niu Dongjie; Sun Jing

    2009-01-01

    A novel method was put forward to on-line evaluate the carbon content of low alloys and carbon steels nondestructively by measuring surface temperature of billet. The practical induction heating process for steel bar was simulated by finite element method. The regression equation for determining carbon content was derived from simulated data. The carbon content and temperature dependence of physical properties,

  16. 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.

  17. Contemporary ultrasonic signal processing approaches for nondestructive evaluation of multilayered structures

    Microsoft Academic Search

    Guang-Ming Zhang; David M. Harvey

    2012-01-01

    Various signal processing techniques have been used for the enhancement of defect detection and defect characterisation. Cross-correlation, filtering, autoregressive analysis, deconvolution, neural network, wavelet transform and sparse signal representations have all been applied in attempts to analyse ultrasonic signals. In ultrasonic nondestructive evaluation (NDE) applications, a large number of materials have multilayered structures. NDE of multilayered structures leads to some

  18. Contemporary ultrasonic signal processing approaches for nondestructive evaluation of multilayered structures

    Microsoft Academic Search

    Guang-Ming Zhang; David M. Harvey

    2011-01-01

    Various signal processing techniques have been used for the enhancement of defect detection and defect characterisation. Cross-correlation, filtering, autoregressive analysis, deconvolution, neural network, wavelet transform and sparse signal representations have all been applied in attempts to analyse ultrasonic signals. In ultrasonic nondestructive evaluation (NDE) applications, a large number of materials have multilayered structures. NDE of multilayered structures leads to some

  19. Nondestructive evaluation of loading and fatigue effects in Haynes(R) 230(R) alloy

    Microsoft Academic Search

    Tarik Adel Saleh

    2006-01-01

    Nondestructive evaluation is a useful method for studying the effects of deformation and fatigue. In this dissertation I employed neutron and X-ray diffraction, nonlinear resonant ultrasound spectroscopy (NRUS), and infrared thermography to study the effects of deformation and fatigue on two different nickel based superalloys. The alloys studied were HAYNES 230, a solid solution strengthened alloy with 4% M6C carbides,

  20. Quantitative phase evaluation of dynamic

    E-print Network

    Chen, Zhongping

    conventional phase-contrast microscopy. © 2008 Society of Photo-Optical Instrumentation Engineers. DOI: 10 advantage of the combination of laser microirradiation and short- coherence interference microscopy. Using.1117/1.2997375 Keywords: laser scissors; short-coherence interference microscopy; quantitative phase imaging; optical

  1. 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

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

    SciTech Connect

    Brennan, R. E.; Green, W. H. [U.S. Army Research Laboratory, 4600 Deer Creek Loop, Aberdeen Proving Ground, MD 21005-5066 (United States)

    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.

  3. Case study of nonlinear inverse problems: mammography and nondestructive evaluation

    E-print Network

    Kreinovich, Vladik

    Case study of non­linear inverse problems: mammography and non­destructive evaluation O. Kosheleva such as faults in non­destructive evaluation or bumps in mammography. Non­linear terms (quadratic or cubic) give. Keywords: Non­linear inverse problem, non­linear data compression, non­destructive evaluation, mammography

  4. Special nondestructive techniques for evaluating space shuttle surface insulation

    NASA Technical Reports Server (NTRS)

    Stinebring, R. C.

    1972-01-01

    NDT techniques have been developed for performing in-process evaluations for material variability and for process control. Several of these techniques show considerable promise for evaluating the reusable surface insulation during the operational phase of the shuttle. Considered are radiographic dosimetry, sonic velocity and modulus sounding, infrared coating evaluation, and beta backscatter monitoring of coating thickness.

  5. 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.

  6. 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.

  7. Nondestructive evaluation for remanent life of modified 9Cr-1Mo steel by reversible magnetic permeability

    NASA Astrophysics Data System (ADS)

    Bong, Chung-jong; Ryu, Kwon-sang; Nahm, Seung-hoon; Kyu Kim, Eun

    2011-03-01

    We present a magnetic and nondestructive method to evaluate the remanent life of modified 9Cr-1Mo steel by measuring the reversible magnetic permeability. Specimens with ten different kinds of aging periods were prepared using an isothermal heat treatment at 690 °C. The Larson-Miller parameter (LMP) was calculated and the peak interval of reversible magnetic permeability (PIRMP) was measured using the surface type probe. PIRMP was inversely proportional to LMP. We can evaluate the remanent life of modified 9Cr-1Mo steel using the relationship between PIRMP and LMP. Also, we present the possibility that the tensile strength and yield strength measured by destructive methods could be estimated by PIRMP measured nondestructively.

  8. 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.

  9. 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.

  10. 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.

  11. Fatigue damage of APC2 composite assessed from material degradation and non-destructive evaluation data

    Microsoft Academic Search

    Sp. G Pantelakis; Em. Ch Kyriakakis

    1999-01-01

    Quasi-isotropic 45° APC-2 specimens are fatigued under constant amplitude stress reversal load condition. Fatigue induced degradation of the mechanical properties is correlated to data obtained from non-destructive evaluation. C-scan readings were used to define a generic damage severity factor D. It refers to the current fatigue damage state and accounts for the varying severity of damage at the different specimen

  12. Elastic-Wave Propagation in Random Polycrystals: Fundamentals and Application to Nondestructive Evaluation

    Microsoft Academic Search

    Bruce R. Thompson

    The fundamental principles that govern the propagation of elastic waves in metal polycrystals are discussed in the context\\u000a of their influence on nondestructive evaluation. The major influence of the polycrystalline microstructure is to determine\\u000a the velocity, attenuation and backscattering of the elastic waves. For randomly oriented, equi-axed polycrystals, these effects\\u000a are reasonably well understood. Waves travel at the same velocity

  13. Proposal of a New Method for Measuring Förster Resonance Energy Transfer (FRET) Rapidly, Quantitatively and Non-Destructively

    PubMed Central

    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 f1 and f2 by electro-optic modulators. In an ensemble exposed to these laser beams, the donor excitation is modulated at f1, and the acceptor excitation, and therefore the degree of saturation of the excited electronic state of the acceptors, is modulated at f2. Since the ensemble contains donor acceptor pairs engaged in FRET, the released donor fluorescence is modulated not only at f1 but also at the beat frequency ?f: = |f1 ? f2|. The depth of the latter modulation, detectable via a lock-in amplifier, quantitatively indicates the FRET efficiency. PMID:23202903

  14. Nondestructive evaluation of residual stress in anisotropic materials

    SciTech Connect

    Johnson, G.C. (California Univ., Berkeley, CA (USA). Dept. of Mechanical Engineering)

    1990-05-01

    The specific focus on anisotropic materials in the research was addressed in a manner which was primarily analytical. All of the experiments involving materials with substantial elastic or plastic anisotropy indicated that the materials in question exhibited a level of acoustoelastic response which was at or below the limit for useful stress evaluation. Nevertheless, the analysis performed indicates that if an experimental system is built which allows determination of the velocity variation roughly an order of magnitude more precisely than is possible with the system used in this work, the complete state of residual stress may be obtained, despite the presence of anisotropy. This report consists of a detailed description of the technique and experimental system proposed for the evaluation of residual stress states. The underlying analytical developments are reviewed, and a numerical investigation into the application of this approach for anisotropic materials is presented. It is shown that an accurate assessment of the complete residual stress state may be obtained even in cases of extreme anisotropy. Finally, an experimental investigation of the technique is presented in which the experimentally determined stress state is compared with that predicted numerically. It is shown that the two estimates of stress agree well for the material involved. 12 refs., 5 figs., 1 tab.

  15. 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.

  16. 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.

  17. Quantitative Evaluation of Poisson Point Process Approximation

    Microsoft Academic Search

    Shozo Mori; Chee-Yee Chong

    This papers is generally concerned with random finite sets or finite point processes that arise from the multiple target tracking problems, more specifically with quantitative evaluation of approximation of a random finite set by a Poisson point process in such an environment. As one of the first attempts in such efforts, we will consider a simple single-scan problem with a

  18. Quantitative evaluation of file management performance improvements

    Microsoft Academic Search

    T. F. McFadden; J. C. Strauss

    1973-01-01

    Operating systems generally provide file management service, routines that are employed by user tasks to access secondary storage. This paper is concerned with quantitative evaluation of several suggested performance improvements to the file management system of the Xerox Data Systems (XDS) operating systems.

  19. Guided waves in a multilayered composite and ultrasonic nondestructive evaluation

    NASA Technical Reports Server (NTRS)

    Datta, S. K.; Karunasena, W. M.; Shah, A. H.

    1991-01-01

    Analysis of wave propagation in a laminated composite plate with many layers is made difficult by the anisotropy of the laminae, different lay-ups, many layers and defects in the fabricated plate. A good understanding of the wave field in such a plate without defects is a prerequisite for use of ultrasonic techniques to evaluate the various defects that can substantially reduce the strength and service life of this structure. Results of modeling studies of wave propagation and scattering in a multilayered composite plate are presented. The analysis technique combines the finite element discretization through the thickness with wave form representation along the plate in order to calculate the dispersive modes of propagation in the plate. To study scattering of these waves by a matrix crack that grows into delaminations, a hybrid finite element representation of the field near the crack and the modal representation of the scattered exterior field are used. Results are presented showing the dependence of the reflection and transmission coefficients on the size of the crack with delamination which can be used to size the defect using ultrasonic techniques.

  20. Millimeter Wave Nondestructive Evaluation of Corrosion Under Paint in Steel Structures

    NASA Astrophysics Data System (ADS)

    Kharkovsky, S.; Zoughi, R.

    2006-03-01

    Millimeter wave nondestructive evaluation techniques have shown great potential for detection of corrosion under paint in steel structures. They may also provide for detection of other anomalies associated with the corrosion process such as precursor pitting. This paper presents the results of an extensive investigation spanning a frequency range of 30-100 GHz and using magnitude- and phase-sensitive reflectometers. Using 2D automated scanning mechanisms, raster images of two corrosion patches are produced showing the spatial resolution capabilities of these systems as well as their potential for evaluating localized corrosion severity.

  1. Nondestructive Evaluation of Composites Using Micro-Focused X-Ray CT Scanner

    SciTech Connect

    Sugimoto, Sunao; Aoki, Takuya; Iwahori, Yutaka; Ishikawa, Takashi [Advanced Composite Evaluation Technology Center, Institute of Space Technology and Aeronautics, Japan Aerospace Exploration Agency, 6-13-1 Ohsawa, Mitaka, Tokyo 181-0015 (Japan)

    2005-04-09

    Micro-Focused X-Ray CT (Micro CT) Scanner has been used for nondestructive evaluation (NDE) of composite materials at Institute of Space Technology and Aeronautics, Japan Aerospace Exploration Agency. Some successful examples of NDE of composites using Micro CT will be presented in this presentation. One example is debonding of fiber/matrix interface, splitting of fiber bundle and matrix crack in carbon/carbon composite. Another example is NDE of stitched CFRP. It was easy to evaluate state of stitch fiber. It has been demonstrated that Micro CT is a powerful device for detecting small damage/flaw in composites, such as delamination, matrix crack and void.

  2. 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.

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

    PubMed

    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. PMID:23020415

  4. 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.

  5. Ultrasonic Excitation by Phase Velocity Scanning of Laser Beam and Application to Nondestructive Evaluation

    NASA Astrophysics Data System (ADS)

    Watanabe, Tomokazu; Cho, Hideo; Yamanaka, Kazushi

    2002-05-01

    It is essential for advanced nondestructive evaluation that single mode of acoustic waves be selectively generated. We have proposed the phase velocity scanning (PVS) method for this purpose. In this work, we improved the PVS method by using an acoustooptic deflector to scan a laser beam at high velocity with high repeatability. In aluminum plates, we succeeded to generate narrow-band single-mode Lamb waves, which propagated a distance more than 1.7 m. We propose to apply this method to detection of defects on large plate structures.

  6. 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.

  7. 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

  8. Microwave nondestructive detection and evaluation of voids in layered dielectric slabs

    SciTech Connect

    Zoughi, R.; Bakhtiari, S. (Colorado State Univ., Fort Collins (USA))

    1990-01-01

    A microwave nondestructive testing technique is discussed for detection and evaluation of voids in layered dielectric media backed by a conducting plate. This technique utilizes the phase properties of the effective reflection coefficient of the medium as a microwave signal penetrates inside the dielectric layers and is reflected by the conducting plate. Properties of the difference between this phase in the absence and presence of an air gap is investigated as a function of the void thickness, frequency, and dielectric properties of the layers. Utilizing a simple experimental apparatus measurements were also conducted, the results of which were compared with the theoretical predictions. 11 refs.

  9. 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.

  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. 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.

  12. Feasibility on fiber orientation detection on unidirectional CFRP composite laminates using nondestructive evaluation techniques

    NASA Astrophysics Data System (ADS)

    Yang, In-Young; Kim, Ji-Hoon; Cha, Cheon-Seok; Lee, Kil-Sung; Hsu, David K.; Im, Kwang-Hee

    2007-07-01

    In particular, CFRP (carbon fiber reinforced plastics) composite materials have found wide applicability because of their inherent design flexibility and improved material properties. CFRP composites were manufactured from uni-direction prepreg sheet in this paper. It is important to assess fiber orientation, material properties and part defect in order to ensure product quality and structural integrity of CFRP because strength and stiffness of composites depend on fiber orientation. It is desirable to perform nondestructive evaluation which is very beneficial. An new method for nondestructively determining the fiber orientation in a composite laminate is presented. A one-sided pitch-catch setup was used in the detection and evaluation of flaws and material anomalies in the unidirectional CFRP composite laminates. Two Rayleigh wave transducers were joined head-to-head and used in the pitch-catch mode on the surface of the composites. The pitch-catch signal was found to be more sensitive than normal incidence backwall echo of longitudinal wave to subtle flaw conditions in the composite. Especially, ultrasonic waves were extensively characterized in the CFRP composite laminates both normal to fiber and along to fiber with using a one-sided direction of Rayleigh wave transducers. Also, one-sided ultrasonic measurement was made with using a Rayleigh wave transducers and a conventional scanner was used in an immersion tank for extracting fiber orientation information from the ultrasonic reflection in the unidirectional laminate. Therefore, it is thought that the proposed method is useful to evaluate integrity of CFRP laminates.

  13. 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.

  14. Scanning laser-line source technique for nondestructive evaluation of cracks in human teeth.

    PubMed

    Sun, Kaihua; Yuan, Ling; Shen, Zhonghua; Xu, Zhihong; Zhu, Qingping; Ni, Xiaowu; Lu, Jian

    2014-04-10

    This paper describes the first application of a remote nondestructive laser ultrasonic (LU) system for clinical diagnosis of cracks in human teeth, to our knowledge. It performs non-contact cracks detection on small-dimension teeth samples. Two extracted teeth with different types of cracks (cracked tooth and craze lines), which have different crack depths, are used as experimental samples. A series of ultrasonic waves were generated by a scanning laser-line source technique and detected with a laser-Doppler vibrometer on the two samples. The B-scan images and peak-to-peak amplitude variation curves of surface acoustic waves were obtained for evaluating the cracks' position and depth. The simulation results calculated by finite element method were combined with the experimental results for accurately measuring the depth of crack. The results demonstrate that this LU system has been successfully applied on crack evaluation of human teeth. And as a remote, nondestructive technique, it has great potential for early in vivo diagnosis of cracked tooth and even the future clinical dental tests. PMID:24787406

  15. Nondestructive evaluation of fatigue damage on low alloy steel by magnetomechanical acoustic emission technique

    SciTech Connect

    Hiraasawa, T.; Saito, K.; Komura, I. [Toshiba Corp., Yokohama (Japan)

    1995-08-01

    A modified magnetomechanical acoustic emission (MAE) technique, denoted Pulse-MAE, in which the magnetization by current pulse was adopted, was newly developed and its applicability was assessed for the nondestructive detection and evaluation of fatigue damage in reactor pressure vessel steel SFVV2 and SA508 class2. MAE signals were measured with both conventional MAE and Pulse-MAE technique for fatigue damaged specimens having several damage fractions, and peak voltage ratio Vp/Vo, where Vp and Vo were the peak voltage for damaged and undamaged specimen respectively, was chosen as a measure. Vp/Vo was found to increase monotonously at the early stage of fatigue process and the rate of increase in Vp/Vo during the fatigue process was larger in Pulse-MAE than conventional MAE. Therefore, Pulse-MAE technique proved to have higher sensitivity for the detection of fatigue damage compared with the conventional MAE and to have the potential of a practical technique for nondestructive detection and evaluation of fatigue damage in actual components.

  16. 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.

  17. Assessing Primary Water Stress Corrosion Crack Morphology and Nondestructive Evaluation Reliability

    SciTech Connect

    Doctor, Steven R.; Schuster, George J.; Anderson, Michael T.

    2005-12-01

    A research program on primary water stress corrosion cracking (PWSCC) is being conducted by Pacific Northwest National Laboratory (PNNL). In this program, the material degradation problem in Alloys 600, 182 and 82 is being investigated, with objectives that include compiling a knowledge base on all cracking in nickel-base materials at all degradation sites in nuclear power plants, assessing nondestructive evaluation methods using mockups to quantify the detection, sizing, and characterization of tight cracks, determining the role of material parameters, such as welding processes, in the degradation. This work is being conducted as a part of an international cooperative research project that has been set up to leverage efforts in several countries to address a significant and common problem. The U.S. Nuclear Regulatory Commission is leading this cooperative project to address this generic problem in a systematic manner over the next four years. In this paper, published information on the failure history of Alloys 600, 182, and 82 is compiled and presented. The configurations of the welded assemblies that contain these alloys are shown to be important considerations for NDE reliability measurements. The product forms and the welding processes represented in the degraded components are described. The relevant data on crack morphology parameters such as shape and orientation are presented, and their impact on nondestructive evaluation (NDE) reliability is discussed.

  18. 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

  19. 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.

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

    PubMed

    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 ?/2000. PMID:26151206

  1. 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

  2. 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)

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

    NASA Astrophysics Data System (ADS)

    Gieske, John H.

    1994-09-01

    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 nondestructive 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 list of the companies that support the particular design are provided. Vendors of each scanner type provided hands-on demonstrations of their equipment on aircraft samples in the Federal Aviation Administration (FAA) Aging Aircraft Nondestructive Inspection Validation Center in Albuquerque, New Mexico. 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 to compare the different scanner types. Illustrations of C-scan images obtained during the demonstration are shown.

  4. Compressive strength evaluation of structural lightweight concrete by non-destructive ultrasonic pulse velocity method.

    PubMed

    Bogas, J Alexandre; Gomes, M Glória; Gomes, Augusto

    2013-07-01

    In this paper the compressive strength of a wide range of structural lightweight aggregate concrete mixes is evaluated by the non-destructive ultrasonic pulse velocity method. This study involves about 84 different compositions tested between 3 and 180 days for compressive strengths ranging from about 30 to 80 MPa. The influence of several factors on the relation between the ultrasonic pulse velocity and compressive strength is examined. These factors include the cement type and content, amount of water, type of admixture, initial wetting conditions, type and volume of aggregate and the partial replacement of normal weight coarse and fine aggregates by lightweight aggregates. It is found that lightweight and normal weight concretes are affected differently by mix design parameters. In addition, the prediction of the concrete's compressive strength by means of the non-destructive ultrasonic pulse velocity test is studied. Based on the dependence of the ultrasonic pulse velocity on the density and elasticity of concrete, a simplified expression is proposed to estimate the compressive strength, regardless the type of concrete and its composition. More than 200 results for different types of aggregates and concrete compositions were analyzed and high correlation coefficients were obtained. PMID:23351273

  5. 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.

  6. Quantitative Evaluation of Security Metrics William H. Sanders

    E-print Network

    Sanders, William H.

    Quantitative Evaluation of Security Metrics William H. Sanders Department of Electrical, analysts would like to evaluate the relative merits of each. In each of these scenarios, quantitative security metrics should provide insight on system security and aid security decisions. Quantitative metrics

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. Nondestructive evaluation inspection of the Arlington Memorial Bridge using a robotic assisted bridge inspection tool (RABIT)

    NASA Astrophysics Data System (ADS)

    Gucunski, Nenad; Boone, Shane D.; Zobel, Rob; Ghasemi, Hamid; Parvardeh, Hooman; Kee, Seong-Hoon

    2014-04-01

    The information presented in this report provides a detailed assessment of the condition of the Arlington Memorial Bridge (AMB) deck. The field-data collection was obtained by both the RABIT™ Bridge Inspection Tool and a number of semi-automated non-destructive evaluation (NDE) tools. The deployment of the semi-automated NDE tools was performed to inspect the AMB deck condition and also to validate data obtained by the RABIT™ Bridge Inspection Tool. Data mining and analysis were accomplished through enhanced data interpretation and visualization capabilities using advanced data integration, fusion, and 2D rendering. One of the major challenges that the research team had to overcome in assessing the condition of the AMB deck was the presence of an asphalt overlay on the entire bridge deck.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Standard practice for digital imaging and communication in nondestructive evaluation (DICONDE) for ultrasonic test methods

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This practice facilitates the interoperability of ultrasonic imaging equipment by specifying image data transfer and archival storage methods in commonly accepted terms. This document is intended to be used in conjunction with Practice E 2339 on Digital Imaging and Communication in Nondestructive Evaluation (DICONDE). Practice E 2339 defines an industrial adaptation of the NEMA Standards Publication titled Digital Imaging and Communications in Medicine (DICOM, see http://medical.nema.org), an international standard for image data acquisition, review, transfer and archival storage. The goal of Practice E 2339, commonly referred to as DICONDE, is to provide a standard that facilitates the display and analysis of NDE test results on any system conforming to the DICONDE standard. Toward that end, Practice E 2339 provides a data dictionary and set of information modules that are applicable to all NDE modalities. This practice supplements Practice E 2339 by providing information object definitions, information ...

  18. 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.

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

    SciTech Connect

    Clayton, Dwight A [ORNL] [ORNL; Bakhtiari, Sasan [Argonne National Laboratory (ANL)] [Argonne National Laboratory (ANL); Smith, Cyrus M [ORNL] [ORNL; Simmons, Kevin [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Ramuhalli, Pradeep [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Coble, Jamie [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Brenchley, David [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL); Meyer, Ryan [Pacific Northwest National Laboratory (PNNL)] [Pacific Northwest National Laboratory (PNNL)

    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).

  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. 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.

  2. 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

  3. 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.

  4. Nondestructive testing and evaluation of composites by non-invasive IR Imaging techniques

    NASA Astrophysics Data System (ADS)

    Mulaveesala, Ravibabu; Siddiqui, Juned A.; Arora, Vanita; Ghali, S. V.; Muniyappa, Amarnath; Takei, Masahiro

    2013-05-01

    InfraRed Thermography (IRT) is one of the promising technique for non-destructive testing method for characterization of materials. This technique relies on evaluation of the surface temperature variations to detect the presence of surface and subsurface anomalies within the material. Due to its whole field and remote testing capabilities, IRT has gained significant importance in testing of Glass Fiber Reinforced Plastic (GFRP) materials. A GFRP sample with defects of various sizes at a given depth was inspected using non-stationary thermographic techniques. In order to highlight the defect detection capabilities of the proposed non-stationary schemes, a comparison has been made using matched excitation energy in frequency domain by taking signal to noise ratio into consideration.

  5. 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.

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

    SciTech Connect

    Guan, Xuefei; Zhang, Jingdan; Zhou, S. Kevin [Siemens Corporation, Corporate Technology, 755 College Rd. E., Princeton NJ 08540 (United States); Rasselkorde, El Mahjoub; Abbasi, Waheed A. [Siemens Energy Inc., 841 Old Frankstown Road, Pittsburgh PA 15239 (United States)

    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.

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

    DOEpatents

    Jiles, David C. (Ames, IA); Sipahi, Levent B. (Ames, IA)

    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.

  8. The probability of flaw detection and the probability of false calls in nondestructive evaluation equipment

    NASA Technical Reports Server (NTRS)

    Temple, Enoch C.

    1994-01-01

    The space industry has developed many composite materials that have high durability in proportion to their weights. Many of these materials have a likelihood for flaws that is higher than in traditional metals. There are also coverings (such as paint) that develop flaws that may adversely affect the performance of the system in which they are used. Therefore there is a need to monitor the soundness of composite structures. To meet this monitoring need, many nondestructive evaluation (NDE) systems have been developed. An NDE system is designed to detect material flaws and make flaw measurements without destroying the inspected item. Also, the detection operation is expected to be performed in a rapid manner in a field or production environment. Some of the most recent video-based NDE methodologies are shearography, holography, thermography, and video image correlation.

  9. The probability of flaw detection and the probability of false calls in nondestructive evaluation equipment

    NASA Astrophysics Data System (ADS)

    Temple, Enoch C.

    1994-10-01

    The space industry has developed many composite materials that have high durability in proportion to their weights. Many of these materials have a likelihood for flaws that is higher than in traditional metals. There are also coverings (such as paint) that develop flaws that may adversely affect the performance of the system in which they are used. Therefore there is a need to monitor the soundness of composite structures. To meet this monitoring need, many nondestructive evaluation (NDE) systems have been developed. An NDE system is designed to detect material flaws and make flaw measurements without destroying the inspected item. Also, the detection operation is expected to be performed in a rapid manner in a field or production environment. Some of the most recent video-based NDE methodologies are shearography, holography, thermography, and video image correlation.

  10. Nondestructive Evaluation of Transient Fission Gas Release from a Pulse-Irradiated PWR Segment Fuel by Counting Krypton 85

    Microsoft Academic Search

    Kazuaki YANAGISAWA

    1992-01-01

    An experimental study was made in the Nuclear Safety Research Reactor at JAERI to evaluate transient fission gas release (FGR) from high burn-up PWR type fuel rods using a nondestructive technique, the counting of radioactive Kr in the fuel plenum. Within the scope of this experiment, the following results were obtained:1. By using the pulse irradiation technique, the radioactivity of

  11. 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.

  12. The nondestructive evaluation of thermal barrier coatings: Measurements of thermal properties and associated defects

    NASA Astrophysics Data System (ADS)

    Yu, Fengling

    2005-11-01

    Phase of thermal emission spectroscopy is developed to nondestructively determine the thermal properties of thermal barrier coatings (TBC). Harmonic heating of the coating is established using a CO2 laser. The phase of thermal emission is measured from the front surface as a function of laser frequency. A mathematical model is developed to describe the heat transport in the measurement and establish all important dependencies of the emission phase. Least square fitting of the experimental measurement using the model permits determination of the unknown properties of the TBC. Besides the thermal diffusivity of the coating, both the thermal conductivity and volumetric heat capacity of the coating can be determined simultaneously. A UCSB TBC deposited by electron-beam physical vapor deposition (EB-PVD) is measured and used to illustrate the measurement and analysis. Various TBC samples deposited by different deposition techniques with varying process parameters and materials are measured with phase of thermal emission spectroscopy. A set of TBC specimens deposited by EB-PVD with varying process parameters are measured. The influences of coating thickness, rotation rate, and deposition tilt on the thermal properties of coatings are studied. Another set of TBC samples deposited by directed vapor deposition (EB-DVD) with various processing parameters and different coating materials are also measured. The effects of rotation rate of the substrate and the substrate temperature for deposition are investigated. The thermal properties of two kinds of coating materials, 7wt% yittria, partially stabilized zirconia (7YSZ) and samarium zirconate (Sm2Zr2O7) are compared. Based on the phase of thermal emission spectroscopy, a surface area mapping method is developed for inspecting defects in TBCs non-destructively, which is desirable for monitoring the performance and predicting the failures of TBCs in service. Mapping the phase shift over a region of interest can be used to characterize changes in coating properties and the presence of defects. By varying the modulation frequency, this method is able to provide depth information concerning the defects. The unknown properties of the delaminated TBC and the thermal contact resistance introduced by a local delamination are determined quantitatively by phase of thermal emission spectroscopy.

  13. Non-destructive evaluation of thermal barrier coatings using impedance spectroscopy

    Microsoft Academic Search

    Xin Wang; Junfa Mei; Ping Xiao

    2001-01-01

    Determining the oxidation of thermal barrier coatings (TBCs) non-destructively is essential for monitoring the performance of TBCs and predicting the lifetime of TBCs in service. In this research, impedance spectroscopy was used, as a non-destructive tool, to examine the oxidation of thermal barrier coatings (TBCs). Impedance diagrams obtained from impedance measurements at 623 K, were analysed according to equivalent circuit

  14. 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.

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

    SciTech Connect

    Ferguson, M.W.

    1994-12-01

    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.

  16. 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.

  17. 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.

  18. Interdigital dielectrometry sensor design and parameter estimation algorithms for non-destructive materials evaluation

    E-print Network

    Mamishev, Alexander V., 1974-

    1999-01-01

    The major objective of this thesis is to develop instrumentation and parameter estimation algorithms for nondestructive measurement of non-homogeneous material property profiles with fringing electric field dielectrometry ...

  19. Non-destructive evaluation techniques for prosthetic heart valves based on hologram interferometry. Part II: Experimental results and clinical implications.

    PubMed

    Geiger, A W; Zarubin, A M; Fahrenkamp, A; Konertz, W; von Bally, G; Scheld, H H

    1993-07-01

    Non-destructive evaluation by hologram interferometry of seven mechanical and seven bioprosthetic valves was carried out. Irregular fringe patterns suspect of intrinsic valve anomaly which may lead to later dysfunction were detected in one mechanical and six bioprosthetic valves. Histologic examination of two bioprosthetic valves revealed focal degeneration, especially in the fibrosa, in those parts of the leaflets that had obvious anomalies on the holographic interferograms. It was shown that the flow turbulences caused by prosthetic valves can also be evaluated using hologram interferometry. The experimental results, obtained with six different types of prostheses (Lillehei-Kaster, Bjork-Shiley, Omnicarbon, St. Jude Medical, Carpentier-Edwards S.A.V. and Valcor), demonstrated the applicability of this technique to both mechanical and bioprosthetic valves. Carrying out non-destructive screening tests for heart valve prostheses may prevent the implantation of potentially dysfunctional devices. PMID:8269148

  20. Nuclear magnetic resonance nondestructive evaluation of composite materials. Final technical report, 19 September 1987-19 June 10, 1989

    SciTech Connect

    Lind, A.C.; Fry, C.G.

    1990-04-09

    Nuclear magnetic resonance (NMR) was studied for use in the nondestructive evaluation of composite materials, with particular emphasis on NMR imaging. NMR parameters of potential use for generating images showing high contrast between acceptable and unacceptable regions of composites were measured for typical organic matrix materials. The attenuating effects of carbon fibers were measured and relationships were developed to compute the conditions necessary to obtain images of carbon-fiber composites. NMR images of aerospace composites containing poly(aryl-ether-ether-ketone) (PEEK) and epoxy resins were obtained using solid state 13C techniques. The contrast mechanism used for these images was the composites. NMR images of hydrogen in PEEK were also obtained using multiple-pulse techniques to reduce dipolar broadening. Selective pulses were used to obtain images of the spatial variations in the crystalline content of PEEK. The results of these experiments were used to assess the feasibility of using NMR for nondestructive evaluation of composite materials.

  1. Emission and detection of terahertz radiation using two dimensional plasmons in semiconductor nano-heterostructures for nondestructive evaluations

    NASA Astrophysics Data System (ADS)

    Otsuji, Taiichi; Watanabe, Takayuki; Boubanga Tombet, Stephane Albon; Satou, Akira; Ryzhii, Victor; Popov, Vyacheslav; Knap, Wojciech

    2013-05-01

    This paper reviews recent advances in emission and detection of terahertz radiation using two dimensional (2D) plasmons in semiconductor nano-heterostructures for nondestructive evaluations. The 2D plasmon resonance is introduced as the operation principle for broadband emission and detection of terahertz radiation. The device structure is based on a high-electron mobility transistor and incorporates the authors' original asymmetrically interdigitated dual grating gates. Excellent terahertz emission and detection performances are experimentally demonstrated by using InAlAs/InGaAs/InP and/or InGaP/InGaAs/GaAs heterostructure material systems. Their applications to nondestructive material evaluation based on terahertz imaging are also presented.

  2. Emission and detection of terahertz radiation using two-dimensional plasmons in semiconductor nanoheterostructures for nondestructive evaluations

    NASA Astrophysics Data System (ADS)

    Otsuji, Taiichi; Watanabe, Takayuki; Tombet, Stephane Albon Boubanga; Satou, Akira; Ryzhii, Victor; Popov, Vyacheslav; Knap, Wojciech

    2014-03-01

    The recent advances in emission and detection of terahertz radiation using two-dimensional (2-D) plasmons in semiconductor nanoheterostructures for nondestructive evaluations are reviewed. The 2-D plasmon resonance is introduced as the operation principle for broadband emission and detection of terahertz radiation. The device structure is based on a high-electron-mobility transistor and incorporates the authors' original asymmetrically interdigitated dual-grating gates. Excellent THz emission and detection performances are experimentally demonstrated by using InAlAs/InGaAs/InP and/or InGaP/InGaAs/GaAs heterostructure material systems. Their applications to nondestructive material evaluation based on THz imaging are also presented.

  3. 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.

  4. Development of non-destructive methods to evaluate oyster quality by electronic nose technology

    Microsoft Academic Search

    Xiaopei Hu; ParameswaraKumar Mallikarjunan; David Vaughan

    2008-01-01

    The effectiveness of two electronic nose (e-nose) systems to assess the quality of oysters was studied on live oysters stored\\u000a at 4 and 7°C for 14 days. E-nose data were correlated with a trained sensory panel evaluation by quantitative description\\u000a analysis and with aerobic plate count. Oysters stored at both temperatures exhibited varying degrees of microbial spoilage,\\u000a with bacterial load

  5. 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.

  6. 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.

  7. Evaluating laser shearography for nondestructive testing at the Kennedy Space Center

    NASA Astrophysics Data System (ADS)

    Bird, Lisa

    1995-01-01

    The flight hardware in use for the Space Shuttle program is one of a kind equipment and therefore very costly. With safety as the number one concern, and quality following a close second, new and better ways to do nondestructive testing on flight hardware are always being sought. Research on laser shearography turned up a promising test method, and equipment was purchased. During the summer of 1994, the equipment was evaluated for use on various components and the equipment itself was checked out for reliability and ease of use. Work to date has shown that the equipment is difficult to use, but the staff feels that once the training hurdle is done, the equipment has great potential. A few of the areas where the equipment could be used are the external tank, the solid rocket boosters, and structural components of the orbiter itself. The primary goal is to use the equipment to test for debonds, and the secondary goal is to see if the equipment can detect corrosion.

  8. Stochastic-integral models for propagation-of-uncertainty problems in nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Sabbagh, Elias H.; Murphy, R. Kim; Sabbagh, Harold A.; Aldrin, John C.; Knopp, Jeremy; Blodgett, Mark P.

    2013-01-01

    Generalized polynomical chaos (gPC), the probabilistic collocation method (PCM), and analysis of variance (ANOVA) are finding considerable application to problems of interest to engineers in which random parameters are an essential feature of the mathematical model. So far the applications have been mainly to stochastic partial differential equations, but we extend the method to volume-integral equations, which have met great success in electromagnetic nondestructive evaluation (NDE), especially with eddy-currents. The problems of main interest to the NDE community in this connection are concerned with the issue of `propagation of uncertainty' when the relevant parameters are not well characterized, or are known simply as random variables. We demonstrate the ideas by considering a metallic surface that has undergone a shot-peening treatment to reduce residual stresses, and has, therefore, become a random conductivity field. In particular, we show how ANOVA becomes a very promising method for high-dimensional model representation (HDMR) when there are a large number of random variables present in the problem.

  9. An examination of nondestructive evaluation techniques for polymer matrix composite sandwich materials

    NASA Astrophysics Data System (ADS)

    Cosgriff, Laura M.; Roberts, Gary D.; Averbeck, Timothy; Jeanneau, Philippe; Quddus, Michael

    2006-03-01

    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 were examined with multiple NDE techniques including thermographic, radiographic, and laser based methods to investigate the manufactured condition of blades and damage induced from play. Hockey blades in an as received condition and damaged blades used in play were investigated with each technique. NDE images from the blades 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. With shearography, structural elements, damaged regions, and other material variations were detected in the hockey blades. Each technique's advantages and disadvantages were considered in making recommendations for inspection of components made from these types of materials.

  10. 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.

  11. Pore size evaluation of mesoporous organosilicate films by non-destructive X-ray reflectivity methods

    NASA Astrophysics Data System (ADS)

    Chien, Yun-San; Yeh, Yu-Shan; Chen, Yen-Song; Leu, Jih-Perng; Fu, Wei-En

    2015-06-01

    200-nm-thick organosilicate films deposited by mixture of tetraethyl orthosilicate (TEOS) and methyltrimethoxysilane (MTMS) dissolving in different cetrimonium bromide (CTAB)/ethanol ratios were characterized in terms of pore size determination and its distribution. Under the toluene ambient, the pores would adsorb the gas hence elevating the whole film density. The X-ray reflectivity (XRR) equipped with mass flow control was utilized to detect the film density increasing. By fitting with Gaussian function and conversing with Kelvin’s equation, the pore size was increased from 6.2 to 10.8 Å as the CTAB/ethanol ratio increasing to 0.075. It was attributed to the ethanol and CTAB enhanced the TEOS hollow droplets stability and dissolvability. As the CTAB/ethanol ratio is further increased, the pore size is reversely decreased, owing to the formation of solid microspheres. The non-destructive XRR measurement can evaluate the sub-nano pore sizes and its size distribution, which would fascinate the development and characterization of back-end of line process.

  12. 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.

  13. Multi-frequency time-reversal-based imaging for ultrasonic nondestructive evaluation using full matrix capture.

    PubMed

    Fan, Chengguang; Pan, Mengchun; Luo, Feilu; Drinkwater, Bruce

    2014-12-01

    In this paper, two multi-frequency time-reversal (TR)-based imaging algorithms are explored for application to the nondestructive evaluation (NDE) imaging of defects in solids: time reversal with multiple signal classification (TRMUSIC) and a related phase-coherent form (PC-MUSIC). These algorithms are tested with simulated and experimental ultrasonic array data acquired using the full matrix capture (FMC) process. The performance of these algorithms is quantified in terms of their spatial resolution and robustness to noise. The effect of frequency bandwidth is investigated and the results are compared with the single-frequency versions of these algorithms. It is shown that both TR-MUSIC and PCMUSIC are capable of resolving lateral targets spaced closer than the Rayleigh limit, achieving super-resolution imaging. TR-MUSIC can locate the positions of scatterers correctly, whereas the results from PC-MUSIC are less clear because of the presence of multiple peaks in the vicinity of target. However, an advantage of PC-MUSIC is that it can overcome the elongated point spread function that appears in TR-MUSIC images, and hence provide enhanced axial resolution. For high noise levels, TR-MUSIC and PC-MUSIC are shown to provide stable images and suppress the presence of artifacts seen in their single-frequency equivalents. PMID:25474781

  14. 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.

  15. 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.

  16. Design, development and application of a novel microwave nondestructive evaluation sensor based on metamaterial lens

    NASA Astrophysics Data System (ADS)

    Shreiber, Daniel

    Nondestructive Evaluation (NDE) method is one of the primary tools of inspecting different materials for structural reliability. Microwave NDE techniques attract more and more attention from the industry and academia. Microwave NDE techniques have the potential to penetrate deeper into materials such as composites and other dielectrics as compared to ultrasonic techniques. Microwave NDE sensors typically operate in two modes---far field and near field. Although in the far field the standoff distance from the sample is comfortable to a user, the resolution of such sensor is limited by the diffraction limit. This thesis describes design, fabrication and evaluation of a novel microwave NDE sensor based on a metamaterial lens. It was a purpose of this work to design a novel Microwave NDE sensor based on a metamaterial lens. The proposed sensor would combine a comfortable standoff distance from the sample with a subwavelength resolution. It was shown that in the resonant frequency range of 3--4 GHz the designed lenses can focus below the diffraction limit (0.48 lambda) and that defects as small as 0.037 lambda in diameter in a dielectric sample can be detected. The resolution was further improved by introducing a metamaterial lens with resonant frequency of 16.75 GHz. Applicability of the proposed sensor to other samples such as corrosion spot under space shuttle tile and rippling on the surface of carbon fiber composites was shown. The limitations of the method were also discussed. The proposed sensor is a viable alternative to the existing NDE methods and contributes greatly to advances in the field of non destructive evaluation.

  17. A comparison of traditional and emerging ultrasonic methods for the nondestructive evaluation of polymer matrix composites subjected to impact damage

    Microsoft Academic Search

    Richard E. Martin; Donald J. Roth; Charles G. Pergantis; Jaswinder S. Sandhu

    2004-01-01

    This paper presents the results of a comparison study of three ultrasonic nondestructive evaluation (NDE) methods applied to polymer matrix composite (PMC) specimens subjected to impact damage. Samples mainly consisted of various thicknesses of graphite\\/epoxy coupon panels impacted with various energy levels. Traditional pulse-echo and through transmission ultrasonic c-scan techniques were applied to impacted samples and served as the basis

  18. Eddy Current Technique Based on SQUID and GMR Sensors for Non-Destructive Evaluation of Fiber\\/Metal Laminates

    Microsoft Academic Search

    Carmela Bonavolontà; Massimo Valentino; Nicola Marrocco; Giovanni Piero Pepe

    2009-01-01

    In this work we present non-destructive evaluation measurements on fiber\\/metal laminate specimen by using eddy current techniques employing HTc SQUID (superconductive quantum interference device) and giant magneto-resistive (GMR) sensors. Our aim is to compare the performance and the capability of HTc SQUID and GMR sensors to detect the presence of damage inside FML composite materials. Experimental results concerning the detection

  19. Non-Destructive Evaluation of Elastic Targets Using Acousto-Electromagnetic Wave Interaction and Time Reversal Focusing

    Microsoft Academic Search

    Amelia Buerkle; Kamal Sarabandi

    2009-01-01

    The objective of this research is to demonstrate the efficacy of using acoustic and electromagnetic (acousto-EM) wave interaction and time-reversal focusing in the non-destructive evaluation of an object. Acousto-EM wave interaction occurs when an electromagnetic wave scatters from an object under seismic or acoustic illumination; the acoustic vibration of the object gives rise to a frequency modulated scattered electromagnetic field

  20. Application of Near-Field Microwave and Millimeter Wave Nondestructive Testing for Evaluation of Fiber Breakage and Orientation Evaluation in CFRP Composite Patches

    NASA Astrophysics Data System (ADS)

    Kharkovsky, S.; Zoughi, R.

    2005-04-01

    Near-field microwave and millimeter wave nondestructive testing and evaluation techniques have been successfully used for detecting defects such as disbond and delamination in complex composite structures. This paper presents the results of fiber breakage detection and fiber orientation determination in carbon fiber reinforced polymer patches which are used in aerospace industry and civil infrastructure.

  1. Quantitative Hierarchical Threat Evaluation Model for Network Security

    Microsoft Academic Search

    Xiu-Zhen CHEN; ZHENG Qing-Hua; GUAN Xiao-Hong; LIN Chen-Guang

    2006-01-01

    Evaluating security threat status is very important in network security management and analysis. A quantitative hierarchical threat evaluation model is developed in this paper to evaluate security threat status of a computer network system and the computational method is developed based on the structure of the network and the importance of services and hosts. The evaluation policy from bottom to

  2. 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.

  3. 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.

  4. Imaging of local stiffness of damaged polycrystalline copper: nondestructive evaluation by resonance ultrasound microscopy.

    PubMed

    Ogi, Hirotsugu; Hayama, Noritaka; Niho, Hiroki; Hirao, Masahiko; Morishita, Tomohiro

    2007-08-01

    The distribution of the local stiffness of a polycrystalline copper exposed to a creep test was studied by resonance ultrasound microscopy. The local effective modulus was evaluated from the resonance frequency of the isolated langasite oscillator touching the specimen. Defects appeared predominantly on grain boundaries, and they were clearly visualized by the stiffness microscopy through the significant decrease of the effective stiffness. The stiffness within the grains becomes lower regardless of invisible defects. The stiffness distribution was quantitatively analyzed by the contact model between two anisotropic bodies and by the micromechanics modeling. The microscopic stiffness shows much higher sensitivity to the defects than the macroscopic stiffness. PMID:17703654

  5. Demonstration of model-assisted probability of detection evaluation methodology for eddy current nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Aldrin, John C.; Sabbagh, Harold A.; Murphy, R. Kim; Sabbagh, Elias H.; Knopp, Jeremy S.; Lindgren, Eric A.; Cherry, Matthew R.

    2012-05-01

    A model-assisted POD (MAPOD) evaluation approach is explored for the eddy current inspection of fatigue cracks in titanium. Experimental results are presented comparing crack and EDM notch responses and different eddy current measurement systems. The MAPOD evaluation process is performed using a simulated case study, highlighting the benefit of leveraging better models to mitigate variation in the model fit and minimize test sample requirements. The benefit of validating NDE techniques that use inverse methods to estimate uncontrolled measurement conditions is also studied.

  6. An Evaluation of Leaf Biomass?:?Length Ratio as a Tool for Nondestructive Assessment in Eelgrass (Zostera marina L.)

    PubMed Central

    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

  7. 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

  8. Physical Model Assisted Probability of Detection in Nondestructive Evaluation for Detecting of Flaws in Titanium

    E-print Network

    of Flaws in Titanium Forgings Ming Li and William Q. Meeker Department of Statistics and Center testing inspection methods to detect synthetic hard alpha inclusion defects in titanium forging disks. Key, Mixed effects, Titanium forging, Ultrasonic testing. 1 INTRODUCTION 1.1 Background Nondestructive

  9. Non-Destructive Evaluation of Materials Using Pulsed Microwave Interrogating Signals and Acoustic Wave

    E-print Network

    /or geometry, including size, shape, and location of occlusions. For example, in subsurface damage detection dielectric, to detect such anomalies as abnormalities in cell struc- ture and chemical composition as well in electromagnetic material interrogation are oriented to- ward nondestructive or even noninvasive detection

  10. 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.

  11. 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.

  12. a Fiber Optic-Based Thermal Acousto-Photonic System for Noncontacting Nondestructive Evaluation

    NASA Astrophysics Data System (ADS)

    Peters, Bruce R.

    1990-01-01

    The Thermal Acousto-Photonic (TAP) Nondestructive Evaluation (NDE) system is an optically based ultrasonic testing technique which extends the potential applications of ultrasonic flaw detection beyond the current capabilities of traditional piezoelectric transducer based technology. Laser based excitation and optical interferometric detection of acoustic waves are conducted through flexible noncontacting fiber optic probes, and a combination of these two methods is used to locate and characterize surface flaws in structural components. TAP has several advantages over conventional transducers; it is noncontacting, more sensitive, and permits truer pointwise sensing. These attributes increase the potential for in-situ applications and allows ultrasonic testing to be conducted in remote and inaccessible locations on structural components. This dissertation discusses the initial outcome of what is potentially a long term research project to explore the synthesis of photonics and ultrasonics to develop a reliable and rugged system for NDE. Based on a review of the considerable research done in the area of optical ultrasound, it is shown that, at present, TAP is the only all fiber optic system for laser based NDE. First, the excitation leg of the system is discussed. A high energy laser pulse is guided through a fiber optic to an appropriate location on the surface of the test specimen. The focused light creates a localized thermal shock which, in turn, generates a Rayleigh acoustic wave. When the wave interacts with a flaw in its path, the signal is modified by the defect in a way which can be correlated to the dimensions of the flaw. The modified Rayleigh wave is detected by an optical fiber interferometer (OFI) and analyzed using computational methods. The technique of time domain reflectometry and ultrasonic spectroscopy, are applied to determine the location and the salient features of the flaw, respectively. Finally, laser excitation, interferometric detection and signal processing are combined and tests are conducted to verify the capabilities of the all fiber optic NDE system. A list of recommendations and directions for future research brings the dissertation to its conclusion.

  13. 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

  14. A quantitative method to evaluate neutralizer toxicity against Acanthamoeba castellanii.

    PubMed

    Buck, S L; Rosenthal, R A

    1996-09-01

    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

  15. 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

  16. 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.

  17. 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, ?. 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

  18. Nondestructive testing and crack evaluation of ferromagnetic material by using the linearly integrated hall sensor array

    Microsoft Academic Search

    Jinyi Lee; Jiseong Hwang; Jongwoo Jun; Seho Choi

    2008-01-01

    Magnetic flux leakage testing (MFLT), which measures the distribution of a magnetic field on a magnetized specimen by using\\u000a a magnetic sensor such as a Hall sensor, is an effective nondestructive testing (NDT) method for detecting surface cracks\\u000a on magnetized ferromagnetic materials. A scan-type magnetic camera, based on the principle of MFLT, uses an inclined Hall\\u000a sensor array on a

  19. Quantitative evaluation of Ocean Thermal Energy Conversion (OTEC): Executive briefing

    NASA Astrophysics Data System (ADS)

    Gritton, E. C.; Pei, R. Y.; Hess, R. W.

    1980-08-01

    The results of an independent quantitative evaluation of Ocean Thermal Energy Conversion (OTEC) for central station applications are summarized. A central station power plant located in the Gulf of Mexico and delivering power to the mainland United States was emphasized. The evaluation of OTEC is based on three important issues: resource availability, technical feasibility, and cost.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Nondestructive X-ray analysis and petrophysical evaluation of a Cybele votive plaque

    NASA Astrophysics Data System (ADS)

    Vladimirov, Valentin

    2005-09-01

    A votive plaque to Cybele, a unique stone monument from the Roman province of Thracia, was studied by nondestructive X-ray analysis and petrophysical methods (including free-water saturation and ultrasonic velocities) with the aim of determining the mechanical properties of the stone and the efficiency of the conservation procedures. It was shown that treatment with Paraloid B 72 toluol solution results in large increase in Young's and shear modulus of the stone. The analysis of two supposedly detached fragments of the monument indicated that one of them is probably not part of the original material.

  5. A Quantitative Evaluation of Confidence Measures for Stereo Vision

    E-print Network

    Mordohai, Philippos

    A Quantitative Evaluation of Confidence Measures for Stereo Vision Xiaoyan Hu, Student Member, IEEE and multiview stereo. Index Terms--Stereo vision, 3D reconstruction, confidence, correspondence, distinctiveness for stereo matching that compares the most widely used measures as well as several novel techniques proposed

  6. A Quantitative Evaluation of Confidence Measures for Stereo Vision

    E-print Network

    Mordohai, Philippos

    1 A Quantitative Evaluation of Confidence Measures for Stereo Vision Xiaoyan Hu, Student Member binocular and multi-view stereo. Index Terms--Stereo vision, 3D reconstruction, confidence, correspondence confidence measures for stereo matching that compares the most widely used measures as well as several novel

  7. Quantitative design and evaluation of enhancement\\/thresholding edge detectors

    Microsoft Academic Search

    I. E. Abdou; W. K. Pratt

    1979-01-01

    Quantitative design and performance evaluation techniques are developed for the enhancement\\/thresholding class of image edge detectors. The design techniques are based on statistical detection theory and deterministic pattern-recognition classification procedures. The performance evaluation methods developed include: a)deterministic measurement of the edge gradient amplitude; b)comparison of the probabilities of correct and false edge detection; and c) figure of merit computation. The

  8. Magnetic non-destructive evaluation of ruptures of tensile armor in oil risers

    NASA Astrophysics Data System (ADS)

    Pérez-Benitez, J. A.; Padovese, L. R.

    2012-04-01

    Risers are flexible multilayered pipes formed by an inner flexible metal structure surrounded by polymer layers and spiral wound steel ligaments, also known as armor wires. Since these risers are used to link subsea pipelines to floating oil and gas production installations, and their failure could produce catastrophic consequences, some methods have been proposed to monitor the armor integrity. However, until now there is no practical method that allows the automatic non-destructive detection of individual armor wire rupture. In this work we show a method using magnetic Barkhausen noise that has shown high efficiency in the detection of armor wire rupture. The results are examined under the cyclic and static load conditions of the riser. This work also analyzes the theory behind the singular dependence of the magnetic Barkhausen noise on the applied tension in riser armor wires.

  9. Main geophysical techniques used for non-destructive evaluation in cultural built heritage: a review

    NASA Astrophysics Data System (ADS)

    Martinho, E.; Dionísio, A.

    2014-10-01

    Geophysical methodologies have been implemented, tested and validated as diagnostic and /or monitoring tools in artworks or historical monuments. They are non-destructive and can give an image of internal structure of investigated medium. This paper is a review about the main geophysical techniques applied to the study of cultural built heritage (excluding the archaeology field). A brief description of the used methodologies is presented, the main investigations done in this field are showed, the method or methods most appropriate to answer each problem (moisture detection, characterization of the materials, study of the structural continuity of the material, assessment of intervention’s effectiveness) are indicated and the main advances and gaps and future developments are also pointed out.

  10. 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.

  11. Application of Barkhausen noise and ferromagnetic hysteresis for magnetic non-destructive evaluation of multiphase composites and structures

    NASA Astrophysics Data System (ADS)

    Prabhu Gaunkar, Neelam; Kypris, Orfeas; Nlebedim, Cajetan; Jiles, David

    2015-03-01

    Composite ferromagnetic materials with multiple magnetic phases are increasingly being used in applications such as magnetic data storage, magnetic sensors and actuators and exchange-spring magnets. These materials occur in single or multiphase conditions and can undergo phase changes over time or during processing. For these materials, we examine the interrelation between ferromagnetic hysteresis, Barkhausen noise and the material microstructure. We observe that the presence of a second phase in these materials can be detected with the help of Barkhausen noise signals due to the occurrence of additional peaks in the magnetization envelope. This behavior in the magnetic response can serve as a tool for non-destructive evaluation of ferromagnetic materials for which phase constitution and phase changes affect the structural performance.

  12. Nondestructive evaluation of steel structures using a superconducting quantum interference device magnetometer and a neural network system

    NASA Astrophysics Data System (ADS)

    Barbosa, C. Hall; Vellasco, M.; Pacheco, M. A.; Bruno, A. C.; Camerini, C. S.

    2000-10-01

    This work combines two state-of-the-art techniques in the area of magnetic nondestructive evaluation: the application of the superconducting quantum interference device (SQUID) as the magnetic field sensor; and the use of artificial neural networks as analysis tools applied to the detected magnetic signals. Pioneering measurements using the SQUID sensor have been made in steel samples containing various types of flaws, and a neural network system, based on the time-delay neural network and radial basis function algorithms, has been implemented to characterize the flaws. The neural network system aims to, based on the measured magnetic field, provide information about defect geometry, thus allowing the assessment of defect severity, as a basis for maintenance and repair procedures.

  13. Standard practice for digital imaging and communication in nondestructive evaluation (DICONDE) for digital radiographic (DR) test methods

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice facilitates the interoperability of digital X-ray imaging equipment by specifying image data transfer and archival methods in commonly accepted terms. This document is intended to be used in conjunction with Practice E2339 on Digital Imaging and Communication in Nondestructive Evaluation (DICONDE). Practice E2339 defines an industrial adaptation of the NEMA Standards Publication titled Digital Imaging and Communications in Medicine (DICOM, see http://medical.nema.org), an international standard for image data acquisition, review, storage and archival storage. The goal of Practice E2339, commonly referred to as DICONDE, is to provide a standard that facilitates the display and analysis of NDE results on any system conforming to the DICONDE standard. Toward that end, Practice E2339 provides a data dictionary and a set of information modules that are applicable to all NDE modalities. This practice supplements Practice E2339 by providing information object definitions, information modules and a ...

  14. Standard practice for digital imaging and communication in nondestructive evaluation (DICONDE) for X-ray computed tomography (CT) test methods

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice facilitates the interoperability of X-ray computed tomography (CT) imaging equipment by specifying image data transfer and archival storage methods in commonly accepted terms. This document is intended to be used in conjunction with Practice E2339 on Digital Imaging and Communication in Nondestructive Evaluation (DICONDE). Practice E2339 defines an industrial adaptation of the NEMA Standards Publication titled Digital Imaging and Communications in Medicine (DICOM, see http://medical.nema.org), an international standard for image data acquisition, review, storage and archival storage. The goal of Practice E2339, commonly referred to as DICONDE, is to provide a standard that facilitates the display and analysis of NDE test results on any system conforming to the DICONDE standard. Toward that end, Practice E2339 provides a data dictionary and a set of information modules that are applicable to all NDE modalities. This practice supplements Practice E2339 by providing information object definitio...

  15. 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.

  16. 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.

  17. Nondestructive evaluation of titanium alloys. ESCA (Electron Spectroscopy for Chemical Analysis), ISS (Ion Scattering Spectroscopy), and SIMS (Secondary Ion Mass Spectrometry) examination of titanium alloy solid surfaces

    Microsoft Academic Search

    G. D. Mateescu; Y. H. Pao

    1984-01-01

    This report will begin with the description of the basic principles and instrumentation of ESCA (Electron Spectroscopy for Chemical Analysis), ISS (Ion Scattering Spectroscopy), and SIMS (Secondary Ion Mass Spectrometry). Particular emphasis will be placed on those aspects which are of immediate relevance to the nondestructive evaluation of titanium alloys such as: the concept of chemical shift in ESCA, the

  18. EVALUATION OF GLASS FIBER\\/POLYPROPYLENE COMPOSITES BY QUANTITATIVE LASER ULTRASONIC AND ACOUSTIC EMISSION TECHNIQUES

    Microsoft Academic Search

    A. Maslouhi; G. Douchy; S. J. Palm

    The objective of this work is to study the influence of the moulding conditions of manufacture on the mechanical behaviour of the composites, when which they are submitted to mechanical loading. In order to evaluate the quality of interfacial adhesion, two non-destructive testing procedures were combined. Laser ultrasonic was employed to evaluate the state of the composite microstructure depending on

  19. Non-destructive evaluation of polymer coating structures on pharmaceutical pellets using full-field optical coherence tomography.

    PubMed

    Li, Chen; Zeitler, J Axel; Dong, Yue; Shen, Yao-Chun

    2014-01-01

    Full-field optical coherence tomography (FF-OCT) using a conventional light-emitting diode and a complementary metal-oxide semiconductor camera has been developed for characterising coatings on small pellet samples. A set of en-face images covering an area of 700 × 700 ?m(2) was taken over a depth range of 166 ?m. The three-dimensional structural information, such as the coating thickness and uniformity, was subsequently obtained by analysis of the recorded en-face images. Drug-loaded pharmaceutical sustained-release pellets with two coating layers and of a sub-millimetre diameter were studied to demonstrate the usefulness of the developed system. We have shown that both coatings can be clearly resolved and the thickness was determined to be 40 and 50 ?m for the outer and inner coating layers, respectively. It was also found that the outer coating layer is relatively uniform, whereas the inner coating layer has many particle-like features. X-ray computed microtomography measurements carried out on the same pellet sample confirmed all these findings. The presented FF-OCT approach is inexpensive and has better spatial resolution compared with other non-destructive analysis techniques such as terahertz pulsed imaging, and is thus considered advantageous for the quantitative analysis of thin coatings on small pellet samples. PMID:24186321

  20. 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.

  1. Comparison of radiation sources and filtering safety glasses for fluorescent nondestructive evaluation

    NASA Astrophysics Data System (ADS)

    Lopez, Richard Daniel

    This study was directed toward the question of whether recent advancements in radiation sources and test media offered significant improvements over the current state of the art. Included were experiments characterizing common penetrant and magnetic particle materials to determine their fluorescent excitation spectra, and a comparison between the fluorescent excitation spectra and the emission spectra of common excitation sources. The relationship between exciter and test medium directly controls the luminance of a defect indication. As indication luminance increases, the probability of it being detected by the inspector increases. Fluorescent penetrant and magnetic particle test media were originally designed around the widely available filtered medium pressure mercury vapor lamp, which remains the standard excitation radiation source. Test media properties, and the types of available excitation sources have changed with time, and it was unclear whether present-day media was still best excited by the historical standard ultraviolet radiation source. Predictions and experimental work was performed to determine the optimal excitation source for fluorescent nondestructive testing, and to determine which safety lens option would offer the highest probability of detection. Improvement in radiation sources was primarily judged by an increase in fluorophore luminance versus background, which led to an increase in signal-to-noise ratio facilitating better indication detectability. Other factors considered were improved health and safety, and ease of use.

  2. Nondestructive evaluation of bone cement and bone cement/metal interface failure.

    PubMed

    Browne, M; Jeffers, J R T; Saffari, N

    2010-02-01

    To quantify the failure mechanisms related to the loosening of cemented hip joint replacements, novel techniques, capable of monitoring, nondestructively, the initiation and progression of failure during in vitro fatigue tests, were employed. Fatigue testing of model cement and cement-stem test pieces was monitored using acoustic emission (AE) sensors. Once damage was detected, an ultrasonic imaging system was used to obtain an image of the damage site and to measure the stiffness of the affected region. This method of examination provided a detailed insight into the internal crack propagation and delamination patterns. Initial work was conducted on bulk cement specimens subjected to bending and tension. The second stage of the work examined a model stem-cement interface under tensile opening loading conditions. A novel ultrasonic technique was used to measure the bond quality at the cement-metal interface. Progressive delamination was identified over time, and the AE technique was able to identify critical areas of delamination before they could be identified conclusively by ultrasonic imaging. The work has demonstrated the potential of the AE technique as a tool for the preclinical assessment of total hip replacements. PMID:19927335

  3. Nondestructive three-dimensional evaluation of biocompatible materials by microtomography using synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Muller, Bert; Thurner, Philipp; Beckmann, Felix; Weitkamp, Timm; Rau, Christoph; Bernhardt, Ricardo; Karamuk, Erdal; Eckert, Ludwig; Brandt, J.; Buchloh, Stefan; Wintermantel, Erich; Scharnweber, Dieter; Worch, Hartmut

    2002-01-01

    Microtomography based on synchrotron radiation sources is a unique technique for the 3D characterization of different materials with a spatial resolution down to about 1 micrometers . The interface between implant materials (metals, ceramics and polymers) and biological matter is nondestructively accessible, i.e. without preparation artifacts. Since the materials exhibit different x-ray absorption, it can become impossible to visualize implant material and tissue, simultaneously. Here, we show that coating of polymer implants, which are invisible in bone tissue, does not only improve the interfacial properties but also allows the imaging of the interface in detail. Titanium implants, on the other hand, absorb the x-rays stronger than bone tissue. The difference, however, is small enough to quantify the bone formation near interface. Another advantage of microtomography with respect to classical histology is the capability to examine samples in a hydrated state. We demonstrate that ceramic hollow spheres can be imaged before sintering and fibroblasts marked by OsO4 are visible on polymer textiles. Consequently, scaffolds of different materials designed for tissue engineering and implant coatings can be optimized on the basis of the tomograms.

  4. A Hybrid Approach to Structural Health Monitoring Using Nondestructive Evaluation (NDE) and Active Damage Interrogation

    NASA Astrophysics Data System (ADS)

    Engelbart, R. W.; Palmer, D. D.; Pitt, D. M.

    2003-03-01

    With the useful lives of many aircraft being extended, in-service inspection, repair, and related support activities represent a considerable commitment of resources. Periodic maintenance operations involve comprehensive nondestructive inspections (NDI) and significant aircraft downtime for compilation of data, disposition of results, and any needed repairs. Confining the inspections to known or suspected problem areas still requires time to cover the area adequately, and to detect and assess flaws. Reducing this inspection time requires advance knowledge of the condition of the structure with respect to the existence and probable location of defects. Recent work has demonstrated the viability of active damage interrogation (ADI) for continuous monitoring of structural health. Piezoelectric transducers are used to actively excite and sense the vibration characteristics of the structure and use this information to make estimates regarding the health of the structure. By detecting changes in the structure's vibration signature, damage can be detected, localized, and assessed; however, additional information may be needed to accurately quantify flaws or damage. This paper will present a concept for a hybridization of ADI and NDI technologies.

  5. 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.

  6. Evaluation of DNA microarray results with quantitative gene expression platforms

    Microsoft Academic Search

    Roger D Canales; Yuling Luo; James C Willey; Bradley Austermiller; Catalin C Barbacioru; Cecilie Boysen; Kathryn Hunkapiller; Roderick V Jensen; Charles R Knight; Kathleen Y Lee; Yunqing Ma; Botoul Maqsodi; Adam Papallo; Elizabeth Herness Peters; Karen Poulter; Patricia L Ruppel; Raymond R Samaha; Leming Shi; Wen Yang; Lu Zhang; Federico M Goodsaid

    2006-01-01

    We have evaluated the performance characteristics of three quantitative gene expression technologies and correlated their expression measurements to those of five commercial microarray platforms, based on the MicroArray Quality Control (MAQC) data set. The limit of detection, assay range, precision, accuracy and fold-change correlations were assessed for 997 TaqMan Gene Expression Assays, 205 Standardized RT (Sta)RT-PCR assays and 244 QuantiGene

  7. Ultrasonic nondestructive evaluation of matrix structures and nodularity in cast irons

    NASA Astrophysics Data System (ADS)

    Lee, Shen-Chih; Suen, Jia-Ming

    1989-11-01

    The primary purpose of this research was to investigate the nondestructive ultrasonic wave response, in terms of acoustic velocities and attenuation of sound energy, in cast irons with different nodularities and matrix structures and its correlation with mechanical properties. The results indicated that the influences of matrix structures on the acoustic velocities were not apparent in the cast irons investigated. As to the nodularity, when graphites were largely spheroidal in shape ( i. e., nodularity over 80 pct), the velocity of longitudinal waves propagation was about 5300 to 5500 m/s. The velocities seemed to decrease linearly down to nodularity of 25 pct, where velocity was approximately 4800 m/s. Below 25 pct nodularity, the values of acoustic velocity dropped rapidly to about 4000 to 4200 m/s. This represented the velocity of longitudinal waves propagation in gray cast iron, in which the graphites appeared in flake form. The analysis of the attenuation of ultrasonic amplitude indicated that when the nodularity of cast irons is low, the echo sound amplitude will decay more rapidly with respect to distance of echo sound travel. As to the matrix structures, ferritic, bainitic, ferritic-pearlitic (low pearlite content) and tempered martensitic matrix structures were found to have similar ultrasonic attenuation characteristics at the testing frequency of 2 MHz. A higher amount of pearlite (over 90 pct) or fresh martensite in the matrix of cast irons has resulted in faster attenuation of ultrasonic energy, with the fresh martensitic matrix being the fastest. At a testing frequency of 4 MHz, the attenuation of the ultrasonic amplitude in pearlitic and fresh martensitic matrices was found to be even greater than that of 2 MHz. However, other matrices exhibited similar attenuation behavior at both 2 and 4 MHz frequencies. The relationship between the mechanical properties of various cast irons and ultrasonic characteristics was also examined.

  8. 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

  9. Millimeter-wave nondestructive evaluation of glass fiber/epoxy composites subjected to impact fatigue

    NASA Astrophysics Data System (ADS)

    Radford, Donald W.; Ganchev, Stoyan I.; Qaddoumi, Nasser; Beauregard, Guy; Zoughi, Reza

    1994-09-01

    The useful life of a glass fiber/epoxy composite subjected to impact fatigue loading is an important issue in the future design of numerous industrial components. Lifetime predictions have been a problem particularly due to the difficulties encountered in monitoring damage accumulation in composites. It is hypothesized that there is a build up of micro damage, such as matrix micro-cracks and micro-delaminations, even though there is no apparent change in material compliance. A critical level is finally reached at which time the properties of the composite begin to fall and compliance change is evident. In this study the apparent compliance change and the type of damage accumulation is investigated. To measure the compliance change, a test unit was developed that uses a dynamic load measuring system. The load cell measures the load throughout each impact pulse and the compliance and energy absorbed by the specimen is then related to the recorded curve. Initially no change in the impact pulse was apparent; however, after a finite number of cycles the peak load and area under each impact pulse drop, indicating an increase in compliance. Unfortunately, the impact load does not provide information on the form and degree of damage. Thus, millimeter wave nondestructive investigation is used, in conjunction with impact fatigue tests, to examine microstructural aspects of damage initiation and growth. The millimeter wave scanning technique results in detectable damage growth throughout the impact fatigue test. Damage size and growth patterns specific to composites are obvious, and after significant damage can be related to the observable macro damage. Continued development of these investigative techniques promises to enhance the ability of detecting defects and damage growth in fiber reinforced composite materials as well as improving the understanding of impact fatigue initiation in these complex materials.

  10. Simultaneous sum-frequency and vibro-acoustography imaging for nondestructive evaluation and testing applications

    SciTech Connect

    Mitri, F. G.; Silva, G. T.; Greenleaf, J. F.; Fatemi, M. [Department of Physiology and Biomedical Engineering, Ultrasound Research Laboratory, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, Minnesota 55905 (United States); Instituto Nacional de Matematica Pura e Aplicada-IMPA, Rio de Janeiro, RJ 22460-320 (Brazil); Department of Physiology and Biomedical Engineering, Ultrasound Research Laboratory, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, Minnesota 55905 (United States)

    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.

  11. 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.

  12. 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.

  13. Superconducting quantum interference device nondestructive evaluation and probability of detection using a boundary element method measurement model

    NASA Astrophysics Data System (ADS)

    Ewing, Anthony Phillip

    Superconducting QUantum Interference Device's (SQUID's) are being used as tools for Nondestructive Evaluation (NDE) to detect and characterize defects in aging aircraft. To evaluate SQUID NDE reliability, a probability of detection (POD) analysis has been done. A boundary element method (BEM) measurement model using a Green's function developed specifically for crack problems has been constructed for use in the POD analysis. The model simulates the 2-D images of the magnetic field obtained by scanning a SQUID magnetometer over a plate containing a crack and carrying an injected dc-current. POD curves were generated through Monte Carlo simulation using distributions derived from sensitivity analyses and experimental noise measurements. For the conditions simulated, crack lengths of 1.4 mm (dc-measurement) and 0.0134 mm (ac-measurement) could be found with 90% probability of detection and 95% confidence. These small crack lengths suggest that additional experimental noise factors will have be incorporated into the POD analysis before realistic SQUID NDE capability can be accurately quantified.

  14. Quantitative evaluation of gain and losses in quaternary lasers

    SciTech Connect

    Mozer, A.P.; Hausser, S.; Pilkuhn, M.H.

    1985-06-01

    An excellent quantitative description of the temperature dependence of the laser threshold current density and of the relevant T /SUB o/ value of GaInAsP/InP 1.3 ..mu..m lasers has been reached by independent measurements of the recombination coefficients and free carrier absorption losses. The recombination coefficients for the radiative band-to-band transition, nonradiative Auger recombination, and extrinsic recombination were determined experimentally, together with the free carrier absorption, especially the contribution of intervalence band absorption. The quantitative evaluation shows that nonradiative Auger carrier losses play the dominant role in the T /SUB o/ values around room temperature, followed by a smaller contribution due to the intervalence band absorption. Furthermore, combined pressure experiments of laser threshold current and quantum efficiency permit a detailed study of the various loss contributions and demonstrate the influence of the split-off valence band.

  15. Quantitative evaluation of material degradation of thermally aged duplex stainless steels using chemical immersion test

    Microsoft Academic Search

    Y. S. Yi; T. Shoji

    1996-01-01

    In order to develop a non-destructive evaluation technique for detection of thermal aging embrittlement of duplex stainless steels, corrosion tests on unaged and aged specimens of cast duplex stainless steels were performed in 5 wt% HCl solution. After the immersion test, the dissolution rate of specimens was obtained by a dissolved depth measurement with an AFM. In the measurements of

  16. Nondestructive Evaluation of Strain Distribution and Fatigue Distribution from Austenitic Stainless Steel by Using Magnetic Sensors

    SciTech Connect

    Tsuchida, Y.; Enokizono, M. [Department of Electrical and Electronic Engineering, Oita University, 700 Dannoharu, Oita 870-1192 (Japan); Oka, M.; Yakushiji, T. [Department of Computer and Control Engineering, Oita National College of Technology, 1666 Maki, Oita 870-0152 (Japan)

    2007-03-21

    Austenitic stainless steel transforms from austenitic crystal structure to martensitic crystal structure after applying strain or stress. Because martensitic crystal structures have magnetization, strain evaluation and fatigue evaluation can be performed by measuring magnetic properties. This paper describes the measurement of leakage magnetic flux density of remanent magnetization for the strain evaluation and the fatigue evaluation by a typical Hall element sensor for SUS 304 and SUS 304L and by a high-sensitivity thin-film flux-gate magnetic sensor for SUS 316 and SUS 316L.

  17. Interfacial Aspects of Electrodeposited Conductive Fibers/Epoxy Composites using Electro-Micromechanical Technique and Nondestructive Evaluation.

    PubMed

    Park, Joung-Man; Lee, Sang-Il; Kim, Ki-Won; Yoon, Dong-Jin

    2001-05-01

    Interfacial adhesion and nondestructive behavior of the electrodeposited (ED) carbon fiber reinforced composites were evaluated using the electro-micromechanical technique and acoustic emission (AE). Interfacial shear strength (IFSS) of the ED carbon fiber/epoxy composites was higher than that of the untreated case. This might be expected because of the possible chemical and hydrogen bonding based on an electrically adsorbed polymeric interlayer. Logarithmic electrical resistivity of the untreated single-carbon fiber composite increased suddenly to infinity when the fiber fracture occurred, whereas that of the ED composite increased relatively broadly up to infinity. This may be due to the retarded fracture time as a result of the enhanced IFSS. In single- and 10-carbon fiber composites, the number of AE signals coming from the interlayer failure of the ED carbon fiber composite was much larger than that of the untreated composite. As the number of each first fiber fracture increased in the 10-carbon fiber composite, the electrical resistivity increased stepwise, and the slope of logarithmic electrical resistance increased. In the three-graphite filament composite with a narrow 1 time inter-filament distance, the total numbers of the filament fracture and the IFSS were smaller than those of the wider 5 times case. This might be because the interacting fracture energy caused by a filament break could affect the adjacent filaments. Copyright 2001 Academic Press. PMID:11334518

  18. Non-destructive evaluation of degradation in EB-PVD thermal barrier coatings by infrared reflectance spectroscopy

    SciTech Connect

    Flattum, Richard Y.; Cooney, Adam T. [Air Force Research Laboratory, Materials and Manufacturing Directorate, NonDestructive Evaluation Branch, Wright-Patterson AFB, OH (United States)

    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.

  19. A comparison of traditional and emerging ultrasonic methods for the nondestructive evaluation of polymer matrix composites subjected to impact damage

    NASA Astrophysics Data System (ADS)

    Martin, Richard E.; Roth, Donald J.; Pergantis, Charles G.; Sandhu, Jaswinder S.

    2004-07-01

    This paper presents the results of a comparison study of three ultrasonic nondestructive evaluation (NDE) methods applied to polymer matrix composite (PMC) specimens subjected to impact damage. Samples mainly consisted of various thicknesses of graphite/epoxy coupon panels impacted with various energy levels. Traditional pulse-echo and through transmission ultrasonic c-scan techniques were applied to impacted samples and served as the basis for comparison. Specimens were then inspected using acoustography, a large field ultrasonic inspection technique that is analogous to real-time X-ray imaging. Acoustography utilizes a unique, wide area two-dimensional (2-D) detector, called an acousto-optic (AO) sensor, to directly convert ultrasound into visual images; much like an image intensifier in real-time radiography. Finally, a newly developed guided wave scanning system was utilized to inspect the same set of samples. This system uses two transducers in a pitch catch configuration to examine the total (multi-mode) ultrasonic response in its inspection analysis. Several time- and frequency-domain parameters are calculated from the ultrasonic guided wave signal at each scan location to form images. Results are presented for all of the methods demonstrating each technique's detection capabilities and highlighting their advantages and disadvantages.

  20. Design and preliminary results from a high temperature superconducting SQUID milliscope used for non-destructive evaluation

    SciTech Connect

    Espy, M.A.; Atencio, L.; Flynn, E.R.; Kraus, R.H. Jr.; Matlashov, A.

    1998-12-31

    The authors present the design and preliminary results from a SQUID milliscope. The device was designed for nondestructive evaluation (NDE) as part of the Enhanced Surveillance Program at Los Alamos National Laboratory and uses a high temperature superconducting (HTS) SQUID sensor to map magnetic fields induced in the sample. Eddy currents are induced in the conducting sample by a wire coil designed to produce minimal magnetic field at the SQUID when no sample is present. The features of interest are characterized by anomalies in the induced magnetic field. The goal of the instrument is sensitivity to small features generally buried under several intervening layers ({approximately}1--10 mm) of conducting and/or non-conducting materials and robustness of design (i.e., the ability to operate in a noisy, unshielded environment). The device has primarily focused on specific NDE problems such as the ability to detect buried seams in conducting materials and quantify the width of these seams. The authors present the design of the instrument, and some data to demonstrate its capabilities.

  1. Roadmap for Nondestructive Evaluation of Reactor Pressure Vessel Research and Development by the Light Water Reactor Sustainability Program

    SciTech Connect

    Smith, Cyrus M [ORNL; Nanstad, Randy K [ORNL; Clayton, Dwight A [ORNL; Matlack, Katie [Georgia Institute of Technology; Ramuhalli, Pradeep [Pacific Northwest National Laboratory (PNNL); Light, Glenn [Southwest Research Institute, San Antonio

    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.

  2. Simulation evaluation of quantitative myocardial perfusion assessment from cardiac CT

    NASA Astrophysics Data System (ADS)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

    2014-03-01

    Contrast enhancement on cardiac CT provides valuable information about myocardial perfusion and methods have been proposed to assess perfusion with static and dynamic acquisitions. There is a lack of knowledge and consensus on the appropriate approach to ensure 1) sufficient diagnostic accuracy for clinical decisions and 2) low radiation doses for patient safety. This work developed a thorough dynamic CT simulation and several accepted blood flow estimation techniques to evaluate the performance of perfusion assessment across a range of acquisition and estimation scenarios. Cardiac CT acquisitions were simulated for a range of flow states (Flow = 0.5, 1, 2, 3 ml/g/min, cardiac output = 3,5,8 L/min). CT acquisitions were simulated with a validated CT simulator incorporating polyenergetic data acquisition and realistic x-ray flux levels for dynamic acquisitions with a range of scenarios including 1, 2, 3 sec sampling for 30 sec with 25, 70, 140 mAs. Images were generated using conventional image reconstruction with additional image-based beam hardening correction to account for iodine content. Time attenuation curves were extracted for multiple regions around the myocardium and used to estimate flow. In total, 2,700 independent realizations of dynamic sequences were generated and multiple MBF estimation methods were applied to each of these. Evaluation of quantitative kinetic modeling yielded blood flow estimates with an root mean square error (RMSE) of ~0.6 ml/g/min averaged across multiple scenarios. Semi-quantitative modeling and qualitative static imaging resulted in significantly more error (RMSE = ~1.2 and ~1.2 ml/min/g respectively). For quantitative methods, dose reduction through reduced temporal sampling or reduced tube current had comparable impact on the MBF estimate fidelity. On average, half dose acquisitions increased the RMSE of estimates by only 18% suggesting that substantial dose reductions can be employed in the context of quantitative myocardial blood flow estimation. In conclusion, quantitative model-based dynamic cardiac CT perfusion assessment is capable of accurately estimating MBF across a range of cardiac outputs and tissue perfusion states, outperforms comparable static perfusion estimates, and is relatively robust to noise and temporal subsampling.

  3. Simulation Evaluation of Quantitative Myocardial Perfusion Assessment from Cardiac CT.

    PubMed

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R; La Riviere, Patrick J; Alessio, Adam M

    2014-03-19

    Contrast enhancement on cardiac CT provides valuable information about myocardial perfusion and methods have been proposed to assess perfusion with static and dynamic acquisitions. There is a lack of knowledge and consensus on the appropriate approach to ensure 1) sufficient diagnostic accuracy for clinical decisions and 2) low radiation doses for patient safety. This work developed a thorough dynamic CT simulation and several accepted blood flow estimation techniques to evaluate the performance of perfusion assessment across a range of acquisition and estimation scenarios. Cardiac CT acquisitions were simulated for a range of flow states (Flow = 0.5, 1, 2, 3 ml/g/min, cardiac output = 3,5,8 L/min). CT acquisitions were simulated with a validated CT simulator incorporating polyenergetic data acquisition and realistic x-ray flux levels for dynamic acquisitions with a range of scenarios including 1, 2, 3 sec sampling for 30 sec with 25, 70, 140 mAs. Images were generated using conventional image reconstruction with additional image-based beam hardening correction to account for iodine content. Time attenuation curves were extracted for multiple regions around the myocardium and used to estimate flow. In total, 2,700 independent realizations of dynamic sequences were generated and multiple MBF estimation methods were applied to each of these. Evaluation of quantitative kinetic modeling yielded blood flow estimates with an root mean square error (RMSE) of ?0.6 ml/g/min averaged across multiple scenarios. Semi-quantitative modeling and qualitative static imaging resulted in significantly more error (RMSE = ?1.2 and ?1.2 ml/min/g respectively). For quantitative methods, dose reduction through reduced temporal sampling or reduced tube current had comparable impact on the MBF estimate fidelity. On average, half dose acquisitions increased the RMSE of estimates by only 18% suggesting that substantial dose reductions can be employed in the context of quantitative myocardial blood flow estimation. In conclusion, quantitative model-based dynamic cardiac CT perfusion assessment is capable of accurately estimating MBF across a range of cardiac outputs and tissue perfusion states, outperforms comparable static perfusion estimates, and is relatively robust to noise and temporal subsampling. PMID:25395812

  4. Nondestructive evaluation of sol–gels using terahertz time-domain reflectance spectroscopy to probe the effects of dendrimer incorporation and humidity on sol–gel aging

    Microsoft Academic Search

    Anita R. Taulbee-Combs; Matthew J. Bachus; Kamila M. Wiaderek; William H. Steinecker; Zechariah D. Sandlin; James A. Cox; Gilbert E. Pacey

    2010-01-01

    Terahertz (THz) time-domain reflectance spectroscopy is evaluated as a technique for nondestructive analysis of sol–gels over\\u000a the first week of aging without directly contacting or disturbing the sol–gels. In the sol–gels analyzed, tetramethyl orthosilicate\\u000a (TMOS) is the precursor and polyamidoamine (PAMAM) dendrimers are incorporated into each of two sol–gel sample groups; a third\\u000a control group contains no dendrimer. The study

  5. Nondestructive evaluation of fiber-reinforced polymer composites by an all-fiber-optic phase-shifting electronic speckle pattern interferometer

    Microsoft Academic Search

    Vadakke M. Murukeshan; A. R. Ganesan; Rajpal S. Sirohi; Sant K. Malhotra

    1997-01-01

    In this paper, we present the developmental details of an all fiber optic phase shifting Electronic Speckle Pattern Interferometer (ESPI) and its applications in Non-Destructive Evaluation (NDE) of Glass Fiber Reinforced Plastics (GFRP). Laminates made of GFRP are studied using the developed ESPI system in its shear configuration. This provides a full-field, non-contact method for NDE, and also observation of

  6. 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

  7. NONDESTRUCTIVE EVALUATION OF IN VITRO-STORED PLANTS: A COMPARISON OF VISUAL AND IMAGE ANALYSIS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In vitro plants in slow-growth storage require routine evaluation for assessment of viability and timing of repropagation. Determination of plantlet health by visual assessment is subjective and varies by genus due to variations in growth pattern and plant structure. Developing a standardized syste...

  8. Evaluation of nano/micro composites for nondestructive repair of delaminated structures

    NASA Astrophysics Data System (ADS)

    Venkiteela, Giri; Klein, Matthew; Najm, Husam; Perumalsamy, Balaguru

    2012-04-01

    Results of an experimental evaluation of nano/micro inorganic composites are presented in this paper. Alkali alumino silicates matrices reinforced with nano/micro fibers were used to repair (glue) fractured concrete prisms and test them in three point bending. Further, shear strength of matrices were also obtained using push-up tests. The variables evaluated were mix composition, temperature and specimen size. It is observed that flexural tensile strength of 1000 psi can be achieved from the developed matrices. In some instances when repaired broken prisms were tested, the failure occurred by creation of a new fracture surface. The developed matrices had the fluidity to fill very thin delamination, which can be pumped to reach delamination through small drilled holes. The results show that the compositions obtained in this study have excellent potential for application involving the repair of delamination.

  9. 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.

  10. Size Evaluation of Corrosion Precursor Pitting Using Near-Field Millimeter Wave Nondestructive Testing Methods

    NASA Astrophysics Data System (ADS)

    Ghasr, M.; Carroll, B.; Kharkovsky, S.; Zoughi, R.; Austin, R.

    2005-04-01

    Early detection of corrosion precursor pitting and estimation of its overall dimensions directly affects the required effort and cost associated with repair and maintenance of critical aircraft structural components. The magnitude and phase of a reflected signal from a pitting are directly related to its dimensions. This paper presents a millimeter wave probe and a sizing procedure used to detect and evaluate overall pitting dimensions.

  11. 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.

  12. A utility evaluation of nondestructive testing devices used on asphalt concrete pavements

    E-print Network

    Stoffels, Shelley Marie

    1986-01-01

    for non-deflection devices 73 23 Rel i abi 1 1 ty/Maintenance downtime utility curve . 74 24 Time in serv1ce/degree of development utility curve. 75 25 Form used to aid in evaluation of decision criteria values for the various devices. 79 26 Total... at any fixed frequency, the output of such sensors is directly proportional to deflection. Thus, to measure deflection, it is only necessary to determine the calibration factor for the measurement frequency. The integrated output of a geophone...

  13. 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.

  14. Classification of acoustic emission waveforms for nondestructive evaluation using neural networks

    SciTech Connect

    Barga, R.S.; Melton, R.B.; Friesel, M.A.

    1990-04-01

    Neural networks were applied to the classification of two types of acoustic emission (AE) events, crack growth and fretting, from a simulated airframe joint specimen. Signals were obtained from four sensors at different locations on the test specimen. Multilayered neural networks were trained to classify the signals using the error backpropagation learning algorithm, enabling AE events arising from crack growth to be distinguished from those caused by fretting. In this paper we evaluate the neural network classification performance for sensor location dependent and sensor location independent training and testing sets. Further, we present a new training strategy which significantly reduces the time required to learn large training sets using the error backpropagation learning algorithm, and improves the generalization performance of the network. 10 refs., 6 figs., 3 tabs.

  15. Evaluation of nondestructive evaluation techniques for determination of flawed conditions and the effects of flaws on the burst pressure in Kevlar-epoxy filament-wound spherical test specimens

    Microsoft Academic Search

    W. D. Brosey; M. T. Calfee; J. W. Whittaker; D. A. Waldrop; E. G. Henneke; D. Post; K. L. Reifsnider; R. A. Blake

    1989-01-01

    A study of nondestructive evaluation techniques on spherical filament-wound Kevlar-epoxy test specimens has been performed, and the results are presented. The objectives of the study were (1) to determine the sensitivity of several NDE techniques for the detection of a series of flaw conditions in an enclosed geometry and (2) to determine which flaw conditions affected the mechanical strength of

  16. 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.

  17. 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

    Microsoft Academic Search

    Bossi; B. Knutson; R. Nerenberg; L. Deobald; J. Nelson

    1998-01-01

    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

  18. Quantitative genetic activity graphical profiles for use in chemical evaluation

    SciTech Connect

    Waters, M.D. [Environmental Protection Agency, Washington, DC (United States); Stack, H.F.; Garrett, N.E.; Jackson, M.A. [Environmental Health Research and Testing, Inc., Research Triangle Park, NC (United States)

    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.

  19. [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

  20. Evaluation of a Virucidal Quantitative Carrier Test for Surface Disinfectants

    PubMed Central

    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

  1. 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.

  2. Nondestructive Evaluation of Submicron Delaminations at Polymer/Metal Interface in Flex Circuits

    SciTech Connect

    Nalladega, Vijayaraghava; Sathish, Shamachary [Center for Materials Diagnostics, University of Dayton Research Institute, Dayton, OH 45469 (United States); Brar, Amarjit S. [Seagate Technology, 7801 Computer Avenue South, Bloomington, MN 55435-5489 (United States)

    2006-03-06

    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.

  3. Quantitative evaluation of ultrasonic C-scan image in acoustically homogeneous and layered anisotropic materials using three dimensional ray tracing method.

    PubMed

    Kolkoori, Sanjeevareddy; Hoehne, Christian; Prager, Jens; Rethmeier, Michael; Kreutzbruck, Marc

    2014-02-01

    Quantitative evaluation of ultrasonic C-scan images in homogeneous and layered anisotropic austenitic materials is of general importance for understanding the influence of anisotropy on wave fields during ultrasonic non-destructive testing and evaluation of these materials. In this contribution, a three dimensional ray tracing method is presented for evaluating ultrasonic C-scan images quantitatively in general homogeneous and layered anisotropic austenitic materials. The directivity of the ultrasonic ray source in general homogeneous columnar grained anisotropic austenitic steel material (including layback orientation) is obtained in three dimensions based on Lamb's reciprocity theorem. As a prerequisite for ray tracing model, the problem of ultrasonic ray energy reflection and transmission coefficients at an interface between (a) isotropic base material and anisotropic austenitic weld material (including layback orientation), (b) two adjacent anisotropic weld metals and (c) anisotropic weld metal and isotropic base material is solved in three dimensions. The influence of columnar grain orientation and layback orientation on ultrasonic C-scan image is quantitatively analyzed in the context of ultrasonic testing of homogeneous and layered austenitic steel materials. The presented quantitative results provide valuable information during ultrasonic characterization of homogeneous and layered anisotropic austenitic steel materials. PMID:24008174

  4. Quantitative methods for somatosensory evaluation in atypical odontalgia.

    PubMed

    Porporatti, André Luís; Costa, Yuri Martins; Stuginski-Barbosa, Juliana; Bonjardim, Leonardo Rigoldi; Conti, Paulo César Rodrigues; Svensson, Peter

    2015-01-01

    A systematic review was conducted to identify reliable somatosensory evaluation methods for atypical odontalgia (AO) patients. The computerized search included the main databases (MEDLINE, EMBASE, and Cochrane Library). The studies included used the following quantitative sensory testing (QST) methods: mechanical detection threshold (MDT), mechanical pain threshold (MPT) (pinprick), pressure pain threshold (PPT), dynamic mechanical allodynia with a cotton swab (DMA1) or a brush (DMA2), warm detection threshold (WDT), cold detection threshold (CDT), heat pain threshold (HPT), cold pain detection (CPT), and/or wind-up ratio (WUR). The publications meeting the inclusion criteria revealed that only mechanical allodynia tests (DMA1, DMA2, and WUR) were significantly higher and pain threshold tests to heat stimulation (HPT) were significantly lower in the affected side, compared with the contralateral side, in AO patients; however, for MDT, MPT, PPT, CDT, and WDT, the results were not significant. These data support the presence of central sensitization features, such as allodynia and temporal summation. In contrast, considerable inconsistencies between studies were found when AO patients were compared with healthy subjects. In clinical settings, the most reliable evaluation method for AO in patients with persistent idiopathic facial pain would be intraindividual assessments using HPT or mechanical allodynia tests. PMID:25627886

  5. Evaluation of the 3D visualization of quantitative stereoelectroencephalographic information. New results.

    E-print Network

    Paris-Sud XI, Université de

    Evaluation of the 3D visualization of quantitative stereoelectroencephalographic information. New of the values. Our study is devoted to the evaluation of the quantitative visualization of these signals of the signals. This work describes an experiment conducted with human observers in order to evaluate three

  6. Qualitative and quantitative evaluation of solvent systems for countercurrent separation.

    PubMed

    Friesen, J Brent; Ahmed, Sana; Pauli, Guido F

    2015-01-16

    Rational solvent system selection for countercurrent chromatography and centrifugal partition chromatography technology (collectively known as countercurrent separation) studies continues to be a scientific challenge as the fundamental questions of comparing polarity range and selectivity within a solvent system family and between putative orthogonal solvent systems remain unanswered. The current emphasis on metabolomic investigations and analysis of complex mixtures necessitates the use of successive orthogonal countercurrent separation (CS) steps as part of complex fractionation protocols. Addressing the broad range of metabolite polarities demands development of new CS solvent systems with appropriate composition, polarity (?), selectivity (?), and suitability. In this study, a mixture of twenty commercially available natural products, called the GUESSmix, was utilized to evaluate both solvent system polarity and selectively characteristics. Comparisons of GUESSmix analyte partition coefficient (K) values give rise to a measure of solvent system polarity range called the GUESSmix polarity index (GUPI). Solvatochromic dye and electrical permittivity measurements were also evaluated in quantitatively assessing solvent system polarity. The relative selectivity of solvent systems were evaluated with the GUESSmix by calculating the pairwise resolution (?ip), the number of analytes found in the sweet spot (Nsw), and the pairwise resolution of those sweet spot analytes (?sw). The combination of these parameters allowed for both intra- and inter-family comparison of solvent system selectivity. Finally, 2-dimensional reciprocal shifted symmetry plots (ReSS(2)) were created to visually compare both the polarities and selectivities of solvent system pairs. This study helps to pave the way to the development of new solvent systems that are amenable to successive orthogonal CS protocols employed in metabolomic studies. PMID:25542704

  7. [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

  8. Feasibility study of the IE-SASW method for nondestructive evaluation of containment building structures in nuclear power plants

    Microsoft Academic Search

    D. S. Kim; H. W. Kim; W. S. Seo; K. C. Choi; S. K. Woo

    2002-01-01

    The IE-SASW method, a combination of impact-echo (IE) acoustics with spectral analysis of surface waves (SASW), is proposed as a newly developed nondestructive testing method in concrete structures. This feasibility study examines the IE technique and uses elastic P-wave velocity data as measured from the SASW method on concrete members in nuclear power plant containment structures. It was shown that

  9. 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.

  10. Nondestructive characterization of woven fabric ceramic composites

    SciTech Connect

    Hsu, D.K.; Saini, V. [Iowa State Univ., Ames, IA (United States); Liaw, P.K.; Yu, N.; Miriyala, N.; McHargue, C.J. [Univ. of Tennessee, Knoxville, TN (United States); Snead, L.L.; Lowden, R.A. [Oak Ridge National Lab., TN (United States)

    1995-10-01

    Woven fabric ceramic composites fabricated by the chemical vapor infiltration method are susceptible to high void content and inhomogeneity. The condition of such materials may be characterized nondestructively with ultrasonic methods. In this work, longitudinal and shear waves were used in the quantitative determination of elastic constants of Nicalon{trademark}/SiC composites as a function of volume percent of porosity. Elastic stiffness constants were obtained for both the in-plane and out-of-plane directions with respect to fiber fabric. The effect of porosity on the modulus of woven fabric composites was also modeled and compared to the measured results. Scan images based on the amplitude and time-of-flight of radio frequency (RF) ultrasonic pulses were used for evaluating the material homogeneity for the purpose of optimizing the manufacturing process and for correlation with the mechanical testing results.

  11. 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 (? PCBs: 6.78-140ng g(-1); DDE: 3.15-145ng g(-1); ? 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

  12. NON-DESTRUCTIVE TECHNIQUES FOR THE EVALUATION OF OVERLAY AND THERMAL BARRIER COATINGS ON GAS TURBINE COMPONENTS

    SciTech Connect

    Michael Cybulsky

    1998-03-10

    There is currently no satisfactory method for the non-destructive examination (NDE) of coatings on gas turbine parts and determination of coating thickness, for example, has to be carried out by sectioning of the component and subsequent metallographic analysis. This method, which is both time-consuming and expensive, has nevertheless been used extensively for aero-engine parts to monitor coating quality and to gather statistical information for process control. For large components from utility size gas turbines costs are high and compared with aero-engines, only a limited number of parts can be examined so that the destructive method becomes less attractive both as an inspection technique and for obtaining process control data to measure part to part variations in coating thickness, for example. During engine service protective coatings slowly degrade and this degradation process effectively controls the life of the part, particularly in situations where a thermal barrier coating (TBC) is used to protect against excessive metal temperatures. In this case growth of the oxide at the interface between the bond coat and the TBC leads to a build-up of stress in the TBC which can be relieved by a spalling of the ceramic layer and loss of the protection from the thermal barrier. In situations where the integrity of the TBC system is critical to the survival of the part, some non-destructive method of determining the degradation condition of the bond coat would clearly be advantageous. In this report the results are described of recent progress in a program to develop non-destructive methods to measure coating quality and to monitor the condition of coatings in service. The work which has formed part of the Advanced Turbine Systems (ATS) Project funded by DOE, has involved the use of eddy-current (ET) and ultrasonic (US) methods developed by SouthWest Research Institute (SwRI) who have been responsible for development of the technique.

  13. 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 [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita 565-0871 (Japan); Yokoyama, Masaaki [Kaneka Fundamental Technology Research Alliance Laboratories, Graduate School of Engineering, Osaka University, Suita 565-0871 (Japan); Seki, Shu, E-mail: seki@chem.eng.osaka-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita 565-0871 (Japan); Kaneka Fundamental Technology Research Alliance Laboratories, Graduate School of Engineering, Osaka University, Suita 565-0871 (Japan)

    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.

  14. Quantitative evaluation of stiffness of commercial suture materials.

    PubMed

    Chu, C C; Kizil, Z

    1989-03-01

    The bending stiffness of 22 commercial suture materials of varying size, chemical structure and physical form was quantitatively evaluated using a stiffness tester (Taber V-5, model 150B, Teledyne). The commercial sutures were Chromic catgut; Dexon (polyglycolic acid); Vicryl (polyglactin 910); PDS (polydioxanone); Maxon (polyglycolide-trimethylene carbonate); Silk (coated with silicone); Mersilene (polyester fiber); Tycron (polyester fiber); Ethibond (polyethylene terephthalate coated with polybutylene); Nurolon (nylon 66); Surgilon (nylon 66 coated with silicone); Ethilon (coated nylon 66), Prolene (polypropylene); Dermalene (polyethylene), and Gore-tex (polytetraflouroethylene). These are both natural and synthetic, absorbable and nonabsorbable and monofilament and multifilament sutures. All of these sutures were size 2-0, but Prolene sutures with sizes ranging from 1-0 to 9-0 were also tested to determine the effect of suture size on stiffness. The bending stiffness data obtained showed that a wide range of bending stiffness was observed among the 22 commercial sutures. The most flexible 2-0 suture was Gore-tex, followed by Dexon, Silk, Surgilon, Vicryl (uncoated), Tycron, Nurolon, Mersilene, Ethibond, Maxon, PDS, Ethilon, Prolene, Chromic catgut, coated Vicryl, and lastly, Dermalene. The large porous volume inherent in Gore-tex monofilament suture was the reason for its lowest flexural stiffness. Sutures with a braided structure were generally more flexible than those of a monofilament structure, irrespective of the chemical constituents. Coated sutures had significantly higher stiffness than the corresponding uncoated ones. This is particularly true when polymers rather than wax were used as the coating material. This increase in stiffness is attributable to the loss of mobility under bending force in the fibers and yarns that make up the sutures. An increase in the size of the suture significantly increased the stiffness, and the magnitude of increase depended on the chemical constituent of the suture. The flexural stiffness of sutures was also found to depend on the duration of bending in the test for stiffness. In general, monofilament sutures exhibited the largest time-dependent stiffness. This was most pronounced with the Gore-tex suture. Most braided sutures also showed less time-dependence in stiffness. Nylon sutures did not exhibit this time-dependent phenomenon regardless of physical form. PMID:2919353

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

    Microsoft Academic Search

    David C. Smith

    2005-01-01

    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,

  16. Nondestructive Damage Detection in General Beams

    E-print Network

    Dincal, Selcuk

    2010-12-08

    is also vital for a nation’s economy. Substantial sums of money may be saved upon detecting structural deterioration in a timely manner. Nondestructive damage evaluation (NDE) offers effective and economically feasible solutions to perform such tasks...

  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. Rational selection and quantitative evaluation of antisense oligonucleotides

    Microsoft Academic Search

    Arul Jayaraman; S. Patrick Walton; Martin L. Yarmush; Charles M. Roth

    2001-01-01

    Antisense oligonucleotides are an attractive therapeutic option to modulate specific gene expression. However, not all antisense oligonucleotides are effective in inhibiting gene expression, and currently very few methods exist for selecting the few effective ones from all candidate oligonucleotides. The lack of quantitative methods to rapidly assess the efficacy of antisense oligonucleotides also contributes to the difficulty of discovering potent

  19. 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

    The further development and application of linear array imaging technology to inspect and characterize a series of complex structures is described. Images of three types of adhesively-bonded aluminum plate specimens, each with a specific type of intentionally disbonded region, obtained with an unmodified medical ultrasonic imaging system are presented. Linear array imaging is applied to the inspection of a woven composite plate specimen that was machined to include intentional flaws. This allows us to assess the feasibility of applying linear array imaging technology to the inspection and characterization of complex textile composite materials. We describe the adhesively-bonded aluminum plate specimens and the woven composite plate specimen interrogated. The linear-array imaging methods section briefly reviews how the images were obtained. Results of linear array imaging are primarily presented on an accompanying videotape. Descriptive text as well as still-frame images are provided to aid in the linear array image interpretation.

  20. Evaluation of central venous catheter sepsis by differential quantitative blood culture

    Microsoft Academic Search

    S. T. Fan; C. H. Teoh-Chan; K. F. Lau

    1989-01-01

    The accuracy of differential quantitative blood culture in the diagnosis of central venous catheter sepsis was evaluated in 24 parenterally-fed patients in whom catheter sepsis was suspected. The pour-plate quantitative culture technique was performed immediately before removal of the catheter on blood drawn through the central venous catheter and a peripheral vein. If bacterial colonies in the catheter blood specimen

  1. Nondestructive evaluation and material properties of advanced materials; Proceedings of the Symposium, TMS Annual Meeting, New Orleans, LA, Feb. 17-21, 1991

    SciTech Connect

    Liaw, P.K.; Buck, O.; Wolf, S.M.

    1991-01-01

    Papers presented in these proceedings include those on the high-frequency ultrasonic inspection of green and hipped silicon nitride cylindrical samples, an NDE characterization of the microstructure and mechanical properties of Al-Li alloys, modeling the interaction of ultrasound with pores, and elastic properties of uniaxial-fiber reinforced composites. Attention is also given to anisotropic elastic properties of SiC particulate reinforced aluminum composites, a nondestructive evaluation technology for metal matrix composite billets, ultrasonic techniques for monitoring texture, and the overload effects on fatigue crack growth characteristics of 2014-Al 20 percent SiC composite. Other papers are on dynamic fracture properties of Inco 625 braze joint, laser speckle correlation studies of compression-compression fatigue damage in thick composites, acoustic emission-fracture strength relations for Al/Gr composites, and computed tomography of advanced materials and processes.

  2. 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).

  3. 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).

  4. Quantitative performance-based evaluation of a procedure for flexible design concept generation

    E-print Network

    Cardin, Michel-Alexandre, 1979-

    2011-01-01

    This thesis presents an experimental methodology for objective and quantitative design procedure evaluation based on anticipated lifecycle performance of design concepts, and a procedure for flexible design concept generation. ...

  5. 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…

  6. 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

  7. Quantitative and qualitative evaluation of the aerobic and facultative bacterial flora of voided canine urine 

    E-print Network

    Biggerstaff, Jane

    1978-01-01

    QUANTITATIVE AND QUALITATIVE EVALUATION OF THE AEROBIC AND FACULTATIVE BACTERIAL FLORA OF VOIDED CANINE URINE A Thesis by JANE BIGGERSTAFF Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirements... and content by Chairman of gs}mmittoe) (Head of Department) (Nember (Nember) August 1978 443163 ABSTRACT Quantitative and Qualitative Evaluation of the Aerobic and Facultative Bacterial Flora of Voided Canine Urine. (August, 1978) Jane Biggerstaff, B...

  8. Quantitative evaluation of the kinetics of human enamel simulated caries using photothermal radiometry and modulated luminescence.

    PubMed

    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. PMID:21806252

  9. 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

  10. 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/EBP?-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.

  11. Experimenting with Quantitative Evaluation Tools for Monitoring Operational Security

    Microsoft Academic Search

    Rodolphe Ortalo; Yves Deswarte

    1999-01-01

    This paper presents the results of an experiment of security evaluation. The evaluation method used is based on previous work involving modeling the system as a privilege graph exhibiting the security vulnerabilities and on the computation of measures representing the difficulty for a possible attacker to exploit these vulnerabilities and defeat the security objectives of the system. A set of

  12. An evaluation of protein assays for quantitative determination of drugs

    Microsoft Academic Search

    Katherine M. Williams; Sarah J. Arthur; Gillian Burrell; Fionnuala Kelly; Darren W. Phillips; Thomas Marshall

    2003-01-01

    We have evaluated the response of six protein assays [the biuret, Lowry, bicinchoninic acid (BCA), Coomassie Brilliant Blue (CBB), Pyrogallol Red–Molybdate (PRM), and benzethonium chloride (BEC)] to 21 pharmaceutical drugs. The drugs evaluated were analgesics (acetaminophen, aspirin, codeine, methadone, morphine and pethidine), antibiotics (amoxicillin, ampicillin, gentamicin, neomycin, penicillin G and vancomycin), antipsychotics (chlorpromazine, fluphenazine, prochlorperazine, promazine and thioridazine) and water-soluble

  13. 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.

  14. Quantitative evaluation of degenerated tendon model using combined optical coherence elastography and acoustic radiation force method.

    PubMed

    Guan, Guangying; Li, Chunhui; Ling, Yuting; Yang, Ying; Vorstius, Jan B; Keatch, Robert P; Wang, Ruikang K; Huang, Zhihong

    2013-11-01

    Damage of collagen fibers in tendons is often directly related to changes in a tendon's mechanical properties. Direct quantitative elasticity measurement of tendons will provide important information in tendon dysfunction diagnosis and treatment assessment. A feasibility study of quantifying the mechanical properties of a degenerated tendon model by a nondestructive imaging modality, which combines optical coherence elastography and acoustic radiation force (ARF) method, is presented. The degenerated tendon model was produced by the partial degradation of chicken tendons through incubation with collagenase at different concentrations and incubation times. A 30-kHz longitudinal ultrasound transducer was used to provide an ARF signal, which was detected by an ultra-high sensitive phase sensitive optical coherence tomography (PhS-OCT) system. The experimental results demonstrate that the combination of ARF method and PhS-OCT can measure the elasticity of tendon quantitatively. The corresponding changes in tendon elasticity due to the application of collagenase have been revealed by this new imaging modality. This method can potentially be used in the assessment of tissue engineering products and in the diagnosis and treatment progression of tendon diseases. PMID:24193945

  15. 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.

  16. Evaluation of respirator fit training by quantitative fit testing 

    E-print Network

    Chute, Daniel Otis

    1981-01-01

    EVALUATION OF RESPiRATOR FIT TRAINING BY OLIANTITATIVE FIT TESTING A Thesis by DANIEL OTIS CHUTE Submitted to the Graduate College of Texas A8M University in partial fulfillment of the requirement for the degree of HASTER OF SCIENCE Auoust... 1981 Major Subject: Industrial Hygiene EVALUATION OF RESPIRATOR FIT TRAINING BY I)UANTITATIVE FIT TESTING A Thesis by Daniel Otis Chute Approved as to style and content by: Chairman f Committ e) (Head o epartment) (Memb (Member) August 1981...

  17. 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.

  18. Evaluation of the National Science Foundation's Local Course Improvement Program, Volume II: Quantitative Analyses.

    ERIC Educational Resources Information Center

    Kulik, James A.; And Others

    This report is the second of three volumes describing the results of the evaluation of the National Science Foundation (NSF) Local Course Improvement (LOCI) program. This volume describes the quantitative results of the program. Evaluation of the LOCI program involved answering questions in the areas of the need for science course improvement as…

  19. Development of motion analysis system for quantitative evaluation of teamwork in soccer games

    Microsoft Academic Search

    Tsuyoshi Taki; Jun-ichi Hasegawa; Teruo Fukumura

    1996-01-01

    We present a motion analysis system of soccer games. The purpose of this system is to evaluate the teamwork quantitatively based on the movement of all the players in a game. Space management and cooperative movement by the players are two major factors for teamwork evaluation. To quantify them from motion images, we propose two new features; “minimum moving time

  20. 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.

  1. 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…

  2. 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...

  3. Quantitative and Qualitative Evaluation of Darpa Communicator Spoken Dialogue Systems

    Microsoft Academic Search

    Marilyn A. Walker; Rebecca J. Passonneau; Julie E. Boland

    2001-01-01

    This paper describes the application of the PARADISE evaluation framework to the corpus of 662 human-computer dialogues collected in the June 2000 Darpa Communicator data collection. We describe results based on the standard logfile metrics as well as results based on additional qualitative metrics derived using the DATE dialogue act tagging scheme. We show that performance models derived via using

  4. Quantitative Evaluation of Register Pressure on Software Pipelined Loops

    Microsoft Academic Search

    Josep Llosa; Eduard Ayguadé; Mateo Valero

    1998-01-01

    Software Pipelining is a loop scheduling technique that extracts loop parallelism by overlapping the execution of several consecutive iterations. One of the drawbacks of software pipelining is its high register requirements, which increase with the number of functional units and their degree of pipelining. This paper analyzes the register requirements of software pipelined loops. It also evaluates the effects on

  5. Quantitative evaluation of grid size effect on CD uniformity improvement

    Microsoft Academic Search

    Doo-Youl Lee; Sung-Woo Lee; Gi-Sung Yeo; Jung-Hyeon Lee; Han-Ku Cho; Woo-Sung Han

    2003-01-01

    In this paper, evaluation of grid size effect on CD uniformity was investigated. The reduction of the grid size can more elaborately correct CD variation by reducing the local mask uniformity and is expected to decrease the error portion and improve CD uniformity.

  6. 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

  7. 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

  8. Quantitative evaluation of material degradation by Barkhausen noise method

    SciTech Connect

    Yamaguchi, Atsunori; Maeda, Noriyoshi; Sugibayashi, Takuya [Japan Power Engineering and Inspection Corporation, Yokohama (Japan). JAPEIC Research Center

    1995-12-01

    Evaluation the life of nuclear power plant becomes inevitable to extend the plant operating period. This paper applied the magnetic method using Barkhausen noise (BHN) to detect the degradation by fatigue and thermal aging. Low alloy steel (SA 508 cl.2) was fatigued at the strain amplitudes of {+-}1% and {+-}0.4%, and duplex stainless steel (SCS14A) was heated at 400 C for a long period (thermal aging). For the degraded material by thermal aging, BHN was measured and good correlation between magnetic properties and absorption energy of the material was obtained. For fatigued material, BHNM was measured at each predetermined cycle and the effect of stress or strain of the material when it measured was evaluated, and good correlation between BHN and fatigue damage ratio was obtained.

  9. Quantitative evaluation of unstructured peer-to-peer architectures

    Microsoft Academic Search

    Fabr ´ icio Benevenuto; Jose Ismael Jr; Jussara Almeida

    2004-01-01

    This paper provides an extensive performance evaluation of the main features of current unstructured super-peer P2P architectures. It quantifies the performance benefits of each feature over the previously proposed community-based message flooding protocol. Our main results show that the hierarchical super-peer architecture itself and a content-aware query routing mechanism are each responsible for significant reductions on system load, compared with

  10. 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.

  11. An evaluation of protein assays for quantitative determination of drugs.

    PubMed

    Williams, Katherine M; Arthur, Sarah J; Burrell, Gillian; Kelly, Fionnuala; Phillips, Darren W; Marshall, Thomas

    2003-07-31

    We have evaluated the response of six protein assays [the biuret, Lowry, bicinchoninic acid (BCA), Coomassie Brilliant Blue (CBB), Pyrogallol Red-Molybdate (PRM), and benzethonium chloride (BEC)] to 21 pharmaceutical drugs. The drugs evaluated were analgesics (acetaminophen, aspirin, codeine, methadone, morphine and pethidine), antibiotics (amoxicillin, ampicillin, gentamicin, neomycin, penicillin G and vancomycin), antipsychotics (chlorpromazine, fluphenazine, prochlorperazine, promazine and thioridazine) and water-soluble vitamins (ascorbic acid, niacinamide, pantothenic acid and pyridoxine). The biuret, Lowry and BCA assays responded strongly to most of the drugs tested. The PRM assay gave a sensitive response to the aminoglycoside antibiotics (gentamicin and neomycin) and the antipsychotic drugs. In contrast, the CBB assay showed little response to the aminoglycosides and gave a relatively poor response with the antipsychotics. The BEC assay did not respond significantly to the drugs tested. The response of the protein assays to the drugs was further evaluated by investigating the linearity of the response and the combined response of drug plus protein. The results are discussed with reference to drug interference in protein assays and the development of new methods for the quantification of drugs in protein-free solution. PMID:12834962

  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

    Pelivanov, Ivan; Buma, Takashi; Xia, Jinjun; Wei, Chen-Wei; O'Donnell, Matthew

    2014-03-21

    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. 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.

  15. Computerized quantitative evaluation of mammographic accreditation phantom images

    SciTech Connect

    Lee, Yongbum; Tsai, Du-Yih; Shinohara, Norimitsu [Department of Radiological Technology, School of Health Sciences, Niigata University, 2-746 Asahimachidori, Chuouku, Niigata 951-8518 (Japan); Department of Radiological Technology, Gifu Univesity of Medical Science, 1-795 Hiraga-aza-nagamine, Seki, Gifu 501-3892 (Japan)

    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.

  16. Enabling sensor technologies for the quantitative evaluation of engineered tissue.

    PubMed

    Starly, Binil; Choubey, Anuja

    2008-01-01

    Research in regenerative medicine has necessitated the need for advanced sensing technologies to monitor and evaluate the quality of engineered tissues. Several sensing schemes have been developed to sense specific analytes that enable researchers to assess tissue morphology, growth, and function. In addition to microscopy and staining techniques, tissue engineers are presented with an array of optical, chemical, and biological sensor technologies, which provide them with an opportunity to monitor variables, such as oxygen concentration, pH value, carbon dioxide, and glucose concentration in a noninvasive or minimally invasive manner. The article presents a short description on the core technologies and research reviews on the use of sensors employed in tissue engineering over the past decade. The article concludes by presenting some of the challenges to the further development of these technologies that are capable of real time measurement of tissue structure, composition, and function both for in-vitro and in-vivo analysis. PMID:17972179

  17. Objective evaluation of reconstruction methods for quantitative SPECT imaging in the absence of ground truth

    NASA Astrophysics Data System (ADS)

    Jha, Abhinav K.; Song, Na; Caffo, Brian; Frey, Eric C.

    2015-03-01

    Quantitative single-photon emission computed tomography (SPECT) imaging is emerging as an important tool in clinical studies and biomedical research. There is thus a need for optimization and evaluation of systems and algorithms that are being developed for quantitative SPECT imaging. An appropriate objective method to evaluate these systems is by comparing their performance in the end task that is required in quantitative SPECT imaging, such as estimating the mean activity concentration in a volume of interest (VOI) in a patient image. This objective evaluation can be performed if the true value of the estimated parameter is known, i.e. we have a gold standard. However, very rarely is this gold standard known in human studies. Thus, no-gold-standard techniques to optimize and evaluate systems and algorithms in the absence of gold standard are required. In this work, we developed a no-gold-standard technique to objectively evaluate reconstruction methods used in quantitative SPECT when the parameter to be estimated is the mean activity concentration in a VOI. We studied the performance of the technique with realistic simulated image data generated from an object database consisting of five phantom anatomies with all possible combinations of five sets of organ uptakes, where each anatomy consisted of eight different organ VOIs. Results indicate that the method pro- vided accurate ranking of the reconstruction methods. We also demonstrated the application of consistency checks to test the no-gold-standard output.

  18. Nondestructive evaluation of titanium alloys. ESCA (Electron Spectroscopy for Chemical Analysis), ISS (Ion Scattering Spectroscopy), and SIMS (Secondary Ion Mass Spectrometry) examination of titanium alloy solid surfaces

    SciTech Connect

    Mateescu, G.D.; Pao, Y.H.

    1984-07-01

    This report will begin with the description of the basic principles and instrumentation of ESCA (Electron Spectroscopy for Chemical Analysis), ISS (Ion Scattering Spectroscopy), and SIMS (Secondary Ion Mass Spectrometry). Particular emphasis will be placed on those aspects which are of immediate relevance to the nondestructive evaluation of titanium alloys such as: the concept of chemical shift in ESCA, the relative surface probing sensitivities of ESCA, ISS, and SIMS, the depth profiling capabilities of these techniques. Preliminary results show that, even at moderate resolution, oxygen first orbit photoelectron spectra of at least three types of oxygen are obtained for the five different Ti alloy samples. Sputtering of the intense Ti2p photoelectron signals corresponds to an oxide which completely covers the surface of the specimen. Carbon 1s spectra served to monitor the degree of contamination. ISS-SIMS measurements provided a better insight into the Oxygen/Ti ratio on the surface and in the subsurface layers. Preliminary investigations demonstrate the feasibility of in situ studies of fracture surfaces. Instrumental modifications for the execution of such experiments are now in progess. Our conclusion is that, working in ultrahigh vacuum conditions, ESCA-ISS-SIMS (combined, perhaps, with conventional mass spectrometry) constitute adequate means to analyze the degree of surface and interstitial oxidation of Ti alloys.

  19. Mechanical Model Analysis for Quantitative Evaluation of Liver Fibrosis Based on Ultrasound Tissue Elasticity Imaging

    NASA Astrophysics Data System (ADS)

    Shiina, Tsuyoshi; Maki, Tomonori; Yamakawa, Makoto; Mitake, Tsuyoshi; Kudo, Masatoshi; Fujimoto, Kenji

    2012-07-01

    Precise evaluation of the stage of chronic hepatitis C with respect to fibrosis has become an important issue to prevent the occurrence of cirrhosis and to initiate appropriate therapeutic intervention such as viral eradication using interferon. Ultrasound tissue elasticity imaging, i.e., elastography can visualize tissue hardness/softness, and its clinical usefulness has been studied to detect and evaluate tumors. We have recently reported that the texture of elasticity image changes as fibrosis progresses. To evaluate fibrosis progression quantitatively on the basis of ultrasound tissue elasticity imaging, we introduced a mechanical model of fibrosis progression and simulated the process by which hepatic fibrosis affects elasticity images and compared the results with those clinical data analysis. As a result, it was confirmed that even in diffuse diseases like chronic hepatitis, the patterns of elasticity images are related to fibrous structural changes caused by hepatic disease and can be used to derive features for quantitative evaluation of fibrosis stage.

  20. Quantitative evaluation of general corrosion of Type 304 stainless steel in subcritical and

    E-print Network

    Benning, Liane G.

    - sion, such as pitting and stress corrosion cracking. However, potential or current monitoring can onlyQuantitative evaluation of general corrosion of Type 304 stainless steel in subcritical the corrosion rate of Type 304 stainless steel (SS) in subcritical and supercritical environments. The EN

  1. Towards a Quantitative Evaluation of Geospatial Metadata Quality in the Context of Semantic

    E-print Network

    Towards a Quantitative Evaluation of Geospatial Metadata Quality in the Context of Semantic to facilitate the reuse of geospatial data in a distributed and heterogeneous environment. In this process, the provided geospatial metadata that are appropriate for the intended use may be incomplete or not appropriate

  2. Quantitative PCR Assay To Evaluate Ampicillin, Ofloxacin, and Doxycycline for Treatment of Experimental Leptospirosis

    Microsoft Academic Search

    Johann Truccolo; Françoise Charavay; Fabrice Merien; Philippe Perolat

    2002-01-01

    The susceptibility of Leptospira interrogans serovar icterohaemorrhagiae strain Verdun to selected antibiotics used in medical practice (ampicillin, doxycycline, and ofloxacin) was evaluated in a Syrian hamster model, to determine the efficacy of these antibiotics during the course of the disease. A quantitative PCR assay was used to monitor the density of leptospires in blood and in target organs (liver, kidney,

  3. Design of part family robust-to-production plan variations based on quantitative manufacturability evaluation

    E-print Network

    Saitou, Kazuhiro "Kazu"

    , a method is proposed to design product families that are robust to production plan variations, basedDesign of part family robust-to-production plan variations based on quantitative manufacturability evaluation Byungwoo Lee, Kazuhiro Saitou Abstract This paper presents a systematic method for designing part

  4. 2005 Conference on Lasers & Electro-Optics (CLEO) Quantitative Evaluation of Nanoshells as a Contrast Agent

    E-print Network

    Barton, Jennifer K.

    , and finally a refocusing lens to focus light onto the sample. Because the fiber has angled facesCFA1 2005 Conference on Lasers & Electro-Optics (CLEO) Quantitative Evaluation of Nanoshells as a Contrast Agent for Optical Coherence Tomography Anant Agrawal, Stanley Huang, and Joshua Pfefer Centerfor

  5. Evaluation of Lenticonus in Alport’s Syndrome: Quantitative Scheimpflug Analysis

    Microsoft Academic Search

    Wei Zhou; Marc Hirsch; Anna K. Junk; Daniel S. Casper; Richard Braunstein; Janice David; Basil V. Worgul

    2003-01-01

    Anterior lenticonus is an ocular abnormality that can occur in Alport’s syndrome. In this study, Scheimpflug slit imaging analyses were employed for quantitative and objective evaluation of lens changes associated with Alport’s syndrome. It was determined that while the apices of the lenticular protrusions are central in the vertical plane, they are nasally displaced in the horizontal meridian. The eccentricity

  6. An Elephant in the Room: Bias in Evaluating a Required Quantitative Methods Course

    ERIC Educational Resources Information Center

    Fletcher, Joseph F.; Painter-Main, Michael A.

    2014-01-01

    Undergraduate Political Science programs often require students to take a quantitative research methods course. Such courses are typically among the most poorly rated. This can be due, in part, to the way in which courses are evaluated. Students are generally asked to provide an overall rating, which, in turn, is widely used by students, faculty,…

  7. Are Teacher Course Evaluations Biased against Faculty That Teach Quantitative Methods Courses?

    ERIC Educational Resources Information Center

    Royal, Kenneth D.; Stockdale, Myrah R.

    2015-01-01

    The present study investigated graduate students' responses to teacher/course evaluations (TCE) to determine if students' responses were inherently biased against faculty who teach quantitative methods courses. Item response theory (IRT) and Differential Item Functioning (DIF) techniques were utilized for data analysis. Results indicate students…

  8. A Numerical Method for Quantitatively Evaluating Orthodontic Force System during Orthodontic Treatment

    Microsoft Academic Search

    Zhigang Wei; Wencheng Tang; Bing Yan; Baokuan Yang

    2011-01-01

    The aim of this paper is to elucidate a new method for quantitatively evaluating orthodontic force system during orthodontic treatment. Dental cast models were made to obtain digital models with impressions of a patient's dental arch at regular intervals. Then the displacement of each bracket for a period of time was obtained by computer aided inspection. The finite element model

  9. DEVELOPMENT AND EVALUATION OF A QUANTITATIVE ENZYME LINKED IMMUNOSORBENT ASSAY (ELISA) FOR POLYCHLORINATED BIPHENYLS

    EPA Science Inventory

    A 96-well, microplate-based enzyme linked immunosorbent assay (ELISA) for the quantitative determination of PCBs (as Aroclors) in soil has been developed and evaluated. he method detection limits are 8.95 ug/Kg and 10.5 ug/Kg for Aroclors 1248 and 1242, respectively. he ELISA was...

  10. DEVELOPING A QUANTITATIVE MODEL TO EVALUATE AND COMPARE THE PERFORMANCE OF HOSPITALMEDICAL TECHNOLOGIES IN TAIWAN

    Microsoft Academic Search

    Yi-Shan Chen; Wei-Hua Andrew Wang; Tam Chan; Ya-Ting Liang

    2005-01-01

    In this research, we developed a systematic procedure to identify decision-making criteria\\/performance indicators and a quantitative model to evaluate and compare the performance of medical technologies in Taiwan hospitals. Accordingly, Multi-Criteria Decision Analysis (MCDA) and Data Envelopment Analysis (DEA) were used complementarily. The aim of developing such a modeling approach is intended to help hospital executives (1) evaluate and choose

  11. Evaluation of material degradation of 1Cr–1Mo–0.25V steel by non-destructive method

    Microsoft Academic Search

    Chang-Sung Seok; Jae-Mean Koo

    2005-01-01

    In this study, specimens with several different degradation levels were prepared by isothermal aging heat treatment at 630°C for evaluating material degradation of 1Cr–1Mo–0.25V. The results from tensile and fracture tests were compared with those from BI tests, the dc potential drop and the ultrasonic method. These results show that normalized Brinell hardness agrees well with normalized tensile strength at

  12. The evaluation of physical dimension changes as non-destructive measurements for monitoring rigor mortis development in broiler muscles 

    E-print Network

    Cavitt, Leslie Cain

    2000-01-01

    THE EVALUATION OF PHYSICAL DIMENSION CHANGES AS NON- DESTRUCTIVE MEASUREMENTS FOR MONITORING RIGOR MORTIS DEVELOPMENT IN BROILER MUSCLES A Thesis by LESLIE CAIN CAVITT Submitted to the Office of Graduate Studies of Texas A8 M University... IN BROILER MUSCLES A Thesis by LESLIE CAIN CAVITT Submitted to Texas A8 M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved as to t e style and content by: Alan R, Sams (Chair of Committee) ember...

  13. Quantitative evaluation of oligonucleotide surface concentrations using polymerization-based amplification

    PubMed Central

    Hansen, Ryan R.; Avens, Heather J.; Shenoy, Raveesh

    2008-01-01

    Quantitative evaluation of minimal polynucleotide concentrations has become a critical analysis among a myriad of applications found in molecular diagnostic technology. Development of high-throughput, nonenzymatic assays that are sensitive, quantitative and yet feasible for point-of-care testing are thus beneficial for routine implementation. Here, we develop a nonenzymatic method for quantifying surface concentrations of labeled DNA targets by coupling regulated amounts of polymer growth to complementary biomolecular binding on array-based biochips. Polymer film thickness measurements in the 20–220 nm range vary logarithmically with labeled DNA surface concentrations over two orders of magnitude with a lower limit of quantitation at 60 molecules/?m2 (?106 target molecules). In an effort to develop this amplification method towards compatibility with fluorescence-based methods of characterization, incorporation of fluorescent nanoparticles into the polymer films is also evaluated. The resulting gains in fluorescent signal enable quantification using detection instrumentation amenable to point-of-care settings. Figure Polymerization-based amplification for quantitative evaluation of 3’ biotinylated oligonucleotide surface concentrations PMID:18661123

  14. 77 FR 41985 - Use of Influenza Disease Models To Quantitatively Evaluate the Benefits and Risks of Vaccines: A...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-17

    ...Docket No. FDA-2012-N-0001] Use of Influenza Disease Models To Quantitatively Evaluate...public workshop entitled: ``Use of Influenza Disease Models to Quantitatively Evaluate...benefits and risks of a hypothetical influenza vaccine, and to seek from a range...

  15. Combining qualitative and quantitative imaging evaluation for the assessment of genomic DNA integrity: The SPIDIA experience.

    PubMed

    Ciniselli, Chiara Maura; Pizzamiglio, Sara; Malentacchi, Francesca; Gelmini, Stefania; Pazzagli, Mario; Hartmann, Christina C; Ibrahim-Gawel, Hady; Verderio, Paolo

    2015-06-15

    In this note, we present an ad hoc procedure that combines qualitative (visual evaluation) and quantitative (ImageJ software) evaluations of Pulsed-Field Gel Electrophoresis (PFGE) images to assess the genomic DNA (gDNA) integrity of analyzed samples. This procedure could be suitable for the analysis of a large number of images by taking into consideration both the expertise of researchers and the objectiveness of the software. We applied this procedure on the first SPIDIA DNA External Quality Assessment (EQA) samples. Results show that the classification obtained by this ad hoc procedure allows a more accurate evaluation of gDNA integrity with respect to a single approach. PMID:25817220

  16. Sensitivity and Calibration of Non-Destructive Evaluation Method That Uses Neural-Net Processing of Characteristic Fringe Patterns

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.; Weiland, Kenneth E.

    2003-01-01

    This paper answers some performance and calibration questions about a non-destructive-evaluation (NDE) procedure that uses artificial neural networks to detect structural damage or other changes from sub-sampled characteristic patterns. The method shows increasing sensitivity as the number of sub-samples increases from 108 to 6912. The sensitivity of this robust NDE method is not affected by noisy excitations of the first vibration mode. A calibration procedure is proposed and demonstrated where the output of a trained net can be correlated with the outputs of the point sensors used for vibration testing. The calibration procedure is based on controlled changes of fastener torques. A heterodyne interferometer is used as a displacement sensor for a demonstration of the challenges to be handled in using standard point sensors for calibration.

  17. Distortion analysis of magnetic excitation—a novel approach for the non-destructive microstructural evaluation of ferromagnetic steel

    NASA Astrophysics Data System (ADS)

    Moorthy, V.

    2014-05-01

    The presence of a different ferromagnetic material, between the poles of a U-shaped iron-cored electromagnetic (EM) yoke, has been observed to introduce a distortion in the alternating excitation voltage (VE) across the coil around the EM yoke. The influence of four different microstructural conditions of a ferromagnetic 18CrNiMo5 gear steel on the distortion behaviour of the magnetic excitation voltage has been investigated. The time derivative of the excitation voltage (dVE/dt) plotted as a function of total applied voltage (VT) has been found to show a unique shape for each sample with different microstructural conditions. The systematic changes in the height and position of the peak and the trough on the voltage-time derivative profile reflect the difference in the magnetization process for each microstructural condition. This study reveals the good potential of this simple method of distortion analysis of magnetic excitation for a variety of applications related to material evaluation of ferromagnetic steel components.

  18. Non-destructive quality evaluation of pepper (Capsicum annuum L.) seeds using LED-induced hyperspectral reflectance imaging.

    PubMed

    Mo, Changyeun; Kim, Giyoung; Lee, Kangjin; Kim, Moon S; Cho, Byoung-Kwan; Lim, Jongguk; Kang, Sukwon

    2014-01-01

    In this study, we developed a viability evaluation method for pepper (Capsicum annuum L.) seeds based on hyperspectral reflectance imaging. The reflectance spectra of pepper seeds in the 400-700 nm range are collected from hyperspectral reflectance images obtained using blue, green, and red LED illumination. A partial least squares-discriminant analysis (PLS-DA) model is developed to classify viable and non-viable seeds. Four spectral ranges generated with four types of LEDs (blue, green, red, and RGB), which were pretreated using various methods, are investigated to develop the classification models. The optimal PLS-DA model based on the standard normal variate for RGB LED illumination (400-700 nm) yields discrimination accuracies of 96.7% and 99.4% for viable seeds and nonviable seeds, respectively. The use of images based on the PLS-DA model with the first-order derivative of a 31.5-nm gap for red LED illumination (600-700 nm) yields 100% discrimination accuracy for both viable and nonviable seeds. The results indicate that a hyperspectral imaging technique based on LED light can be potentially applied to high-quality pepper seed sorting. PMID:24763251

  19. Visible and near-infrared light transmission: A hybrid imaging method for non-destructive meat quality evaluation

    NASA Astrophysics Data System (ADS)

    Ziadi, A.; Maldague, X.; Saucier, L.; Duchesne, C.; Gosselin, R.

    2012-09-01

    Visual inspection of the amount of external marbling (intramuscular fat) on the meat surface is the official method used to assign the quality grading level of meat. However, this method is based exclusively on the analysis of the meat surface without any information about the internal content of the meat sample. In this paper, a new method using visible (VIS) and near-infrared (NIR) light transmission is used to evaluate the quality of beef meat based on the marbling detection. It is demonstrated that using NIR light in transmission mode, it is possible to detect the fat not only on the surface, as in traditional methods, but also under the surface. Moreover, in combining the analysis of the two sides of the meat simple, it is possible to estimate the volumetric marbling which is not accessible by visual methods commonly proposed in computer vision. To the best of our knowledge, no similar work or method has been published or developed. The experimental results confirm the expected properties of the proposed method and illustrate the quality of the results obtained.

  20. Nondestructive examination development and demonstration plan

    SciTech Connect

    Weber, J.R.

    1991-08-21

    Nondestructive examination (NDE) of waste matrices using penetrating radiation is by nature very subjective. Two candidate systems of examination have been identified for use in WRAP 1. This test plan describes a method for a comparative evaluation of different x-ray examination systems and techniques.

  1. Evaluation of quantitative accuracy in CZT-based pre-clinical SPECT for various isotopes

    NASA Astrophysics Data System (ADS)

    Park, S.-J.; Yu, A. R.; Kim, Y.-s.; Kang, W.-S.; Jin, S. S.; Kim, J.-S.; Son, T. J.; Kim, H.-J.

    2015-05-01

    In vivo pre-clinical single-photon emission computed tomography (SPECT) is a valuable tool for functional small animal imaging, but several physical factors, such as scatter radiation, limit the quantitative accuracy of conventional scintillation crystal-based SPECT. Semiconductor detectors such as CZT overcome these deficiencies through superior energy resolution. To our knowledge, little scientific information exists regarding the accuracy of quantitative analysis in CZT-based pre-clinical SPECT systems for different isotopes. The aim of this study was to assess the quantitative accuracy of CZT-based pre-clinical SPECT for four isotopes: 201Tl, 99mTc, 123I, and 111In. The quantitative accuracy of the CZT-based Triumph X-SPECT (Gamma-Medica Ideas, Northridge, CA, U.S.A.) was compared with that of a conventional SPECT using GATE simulation. Quantitative errors due to the attenuation and scatter effects were evaluated for all four isotopes with energy windows of 5%, 10%, and 20%. A spherical source containing the isotope was placed at the center of the air-or-water-filled mouse-sized cylinder phantom. The CZT-based pre-clinical SPECT was more accurate than the conventional SPECT. For example, in the conventional SPECT with an energy window of 10%, scatter effects degraded quantitative accuracy by up to 11.52%, 5.10%, 2.88%, and 1.84% for 201Tl, 99mTc, 123I, and 111In, respectively. However, with the CZT-based pre-clinical SPECT, the degradations were only 9.67%, 5.45%, 2.36%, and 1.24% for 201Tl, 99mTc, 123I, and 111In, respectively. As the energy window was increased, the quantitative errors increased in both SPECT systems. Additionally, the isotopes with lower energy of photon emissions had greater quantitative error. Our results demonstrated that the CZT-based pre-clinical SPECT had lower overall quantitative errors due to reduced scatter and high detection efficiency. Furthermore, the results of this systematic assessment quantifying the accuracy of these SPECT for various isotopes will provide valuable reference information for the design of CZT-based pre-clinical SPECT system imaging protocols.

  2. Quantitative Ultrasonic Evaluation of Radiation-Induced Late Tissue Toxicity: Pilot Study of Breast Cancer Radiotherapy

    Microsoft Academic Search

    Tian Liu; Jun Zhou; Emi J. Yoshida; Shermian A. Woodhouse; Peter B. Schiff; Tony J. C. Wang; Zheng Feng Lu; Eliza Pile-Spellman; Pengpeng Zhang; Gerald J. Kutcher

    2010-01-01

    Purpose: To investigate the use of advanced ultrasonic imaging to quantitatively evaluate normal-tissue toxicity in breast-cancer radiation treatment. Methods and Materials: Eighteen breast cancer patients who received radiation treatment were enrolled in an institutional review board-approved clinical study. Radiotherapy involved a radiation dose of 50.0 to 50.4 Gy delivered to the entire breast, followed by an electron boost of 10.0

  3. Quantitative Methods for Evaluating the Efficacy of Thalamic Deep Brain Stimulation in Patients with Essential Tremor

    PubMed Central

    Wastensson, Gunilla; Holmberg, Björn; Johnels, Bo; Barregard, Lars

    2013-01-01

    Background Deep brain stimulation (DBS) of the thalamus is a safe and efficient method for treatment of disabling tremor in patient with essential tremor (ET). However, successful tremor suppression after surgery requires careful selection of stimulus parameters. Our aim was to examine the possible use of certain quantitative methods for evaluating the efficacy of thalamic DBS in ET patients in clinical practice, and to compare these methods with traditional clinical tests. Methods We examined 22 patients using the Essential Tremor Rating Scale (ETRS) and quantitative assessment of tremor with the stimulator both activated and deactivated. We used an accelerometer (CATSYS tremor Pen) for quantitative measurement of postural tremor, and a eurythmokinesimeter (EKM) to evaluate kinetic tremor in a rapid pointing task. Results The efficacy of DBS on tremor suppression was prominent irrespective of the method used. The agreement between clinical rating of postural tremor and tremor intensity as measured by the CATSYS tremor pen was relatively high (rs?=?0.74). The agreement between kinetic tremor as assessed by the ETRS and the main outcome variable from the EKM test was low (rs?=?0.34). The lack of agreement indicates that the EKM test is not comparable with the clinical test. Discussion Quantitative methods, such as the CATSYS tremor pen, could be a useful complement to clinical tremor assessment in evaluating the efficacy of DBS in clinical practice. Future studies should evaluate the precision of these methods and long-term impact on tremor suppression, activities of daily living (ADL) function and quality of life. PMID:24255800

  4. Educational ultrasound nondestructive testing laboratory.

    PubMed

    Genis, Vladimir; Zagorski, Michael

    2008-09-01

    The ultrasound nondestructive evaluation (NDE) of materials course was developed for applied engineering technology students at Drexel University's Goodwin College of Professional Studies. This three-credit, hands-on laboratory course consists of two parts: the first part with an emphasis on the foundations of NDE, and the second part during which ultrasound NDE techniques are utilized in the evaluation of parts and materials. NDE applications are presented and applied through real-life problems, including calibration and use of the latest ultrasonic testing instrumentation. The students learn engineering and physical principles of measurements of sound velocity in different materials, attenuation coefficients, material thickness, and location and dimensions of discontinuities in various materials, such as holes, cracks, and flaws. The work in the laboratory enhances the fundamentals taught during classroom sessions. This course will ultimately result in improvements in the educational process ["The greater expectations," national panel report, http://www.greaterexpectations.org (last viewed February, 2008); R. M. Felder and R. Brent "The intellectual development of Science and Engineering Students. Part 2: Teaching to promote growth," J. Eng. Educ. 93, 279-291 (2004)] since industry is becoming increasingly reliant on the effective application of NDE technology and the demand on NDE specialists is increasing. NDE curriculum was designed to fulfill levels I and II NDE in theory and training requirements, according to American Society for Nondestructive Testing, OH, Recommended Practice No. SNT-TC-1A (2006). PMID:19045633

  5. Quantitative evaluation of English-Japanese machine translation of medical literature.

    PubMed

    Kiuchi, T; Kaihara, S

    1991-08-01

    Although many machine-translation programs are currently available, few evaluation methods of such translation exist for any given application area. It is difficult to evaluate machine-translation systems objectively because the quality of a translation depends on the combination of three factors: the translation program, the dictionary, and the original document. In this study, we developed a quantitative evaluation method for assessing machine translation, which evaluates these three factors separately. We applied this method to the translation of English to Japanese for medical literature and the method proved to be a good indicator for further system improvement. Using this method we also discovered other important points for machine translation, such as the examination of target documents for the construction of a better application dictionary. PMID:1943792

  6. In-Situ Nondestructive Evaluation of Kevlar(Registered Trademark)and Carbon Fiber Reinforced Composite Micromechanics for Improved Composite Overwrapped Pressure Vessel Health Monitoring

    NASA Technical Reports Server (NTRS)

    Waller, Jess; Saulsberry, Regor

    2012-01-01

    NASA has been faced with recertification and life extension issues for epoxy-impregnated Kevlar 49 (K/Ep) and carbon (C/Ep) composite overwrapped pressure vessels (COPVs) used in various systems on the Space Shuttle and International Space Station, respectively. Each COPV has varying criticality, damage and repair histories, time at pressure, and pressure cycles. COPVs are of particular concern due to the insidious and catastrophic burst-before-leak failure mode caused by stress rupture (SR) of the composite overwrap. SR life has been defined [1] as the minimum time during which the composite maintains structural integrity considering the combined effects of stress level(s), time at stress level(s), and associated environment. SR has none of the features of predictability associated with metal pressure vessels, such as crack geometry, growth rate and size, or other features that lend themselves to nondestructive evaluation (NDE). In essence, the variability or surprise factor associated with SR cannot be eliminated. C/Ep COPVs are also susceptible to impact damage that can lead to reduced burst pressure even when the amount of damage to the COPV is below the visual detection threshold [2], thus necessitating implementation of a mechanical damage control plan [1]. Last, COPVs can also fail prematurely due to material or design noncompliance. In each case (SR, impact or noncompliance), out-of-family behavior is expected leading to a higher probability of failure at a given stress, hence, greater uncertainty in performance. For these reasons, NASA has been actively engaged in research to develop NDE methods that can be used during post-manufacture qualification, in-service inspection, and in-situ structural health monitoring. Acoustic emission (AE) is one of the more promising NDE techniques for detecting and monitoring, in real-time, the strain energy release and corresponding stress-wave propagation produced by actively growing flaws and defects in composite materials [3,4,5,6,7,8]. To gain further insight into the mechanisms responsible for composite rupture, broadband modal acoustic emission analysis was used. Also, since AE data reduction proved to be very time consuming, specialized data reduction software was written to automate the process.

  7. Evaluation of the Quantitative Prediction of a Trend Reversal on the Japanese Stock Market in 1999

    NASA Astrophysics Data System (ADS)

    Johansen, Anders; Sornette, Didier

    In January 1999, the authors published a quantitative prediction that the Nikkei index should recover from its 14-year low in January 1999 and reach ~20 500 a year later. The purpose of the present paper is to evaluate the performance of this specific prediction as well as the underlying model: the forecast, performed at a time when the Nikkei was at its lowest (as we can now judge in hindsight), has correctly captured the change of trend as well as the quantitative evolution of the Nikkei index since its inception. As the change of trend from sluggish to recovery was estimated quite unlikely by many observers at that time, a Bayesian analysis shows that a skeptical (resp. neutral) Bayesian sees prior belief in our model amplified into a posterior belief 19 times larger (resp. reach the 95% level).

  8. Infrared radiometric technique for rapid quantitative evaluation of heat flux distribution over large areas

    NASA Technical Reports Server (NTRS)

    Glazer, Stuart; Siebes, Georg

    1989-01-01

    This paper describes a novel approach for rapid, quantitative measurement of spatially distributed heat flux incident on a plane. The technique utilizes the spatial temperature distribution on an opaque thin film at the location of interest, as measured by an imaging infrared radiometer. Knowledge of film radiative properties, plus quantitative estimates of convection cooling permit the steady state energy balance at any location on the film sheet to be solved for the incident heat flux. Absolute accuracies on the order of 10-15 percent have been obtained in tests performed in air. The method is particularly useful for evaluation of spatial heat flux uniformity from distributed heat sources over large areas. It has recently been used in several applications at the Jet Propulsion Laboratory, including flux uniformity measurements from large distributed quartz lamp arrays used during thermal vacuum testing of several spacecraft components, and flux mapping of a low power NdYg laser beam.

  9. Improvement of interfacial adhesion and nondestructive damage evaluation for plasma-treated PBO and Kevlar fibers\\/epoxy composites using micromechanical techniques and surface wettability

    Microsoft Academic Search

    Joung-Man Park; Dae-Sik Kim; Sung-Ryong Kim

    2003-01-01

    Comparison of interfacial properties and microfailure mechanisms of oxygen-plasma treated poly(p-phenylene-2,6-benzobisoxazole (PBO, Zylon) and poly(p-phenylene terephthalamide) (PPTA, Kevlar) fibers\\/epoxy composites were investigated using a micromechanical technique and nondestructive acoustic emission (AE). The interfacial shear strength (IFSS) and work of adhesion, Wa, of PBO or Kevlar fiber\\/epoxy composites increased with oxygen-plasma treatment, due to induced hydrogen and covalent bondings at their

  10. Assembling of Fluid Filtration System for Quantitative Evaluation of Microleakage in Dental Materials

    PubMed Central

    Javidi, Maryam; Naghavi, Neda; Roohani, Ehsan

    2008-01-01

    INTRODUCTION: There are several methods for evaluating microleakage in dentistry, for example dye or bacterial leakage, electro-chemical methods, radioisotope labeling and fluid filtration. The purpose of this study was to assemble the fluid filtration system for quantitative evaluation of microleakage in dental materials. MATERIALS AND METHODS: The roots were connected to a tube filled with an underwater pressure supply. A bubble was introduced into the water to measure endodontic leakage. A digital camera and professional software were utilized to record and measure the bubble displacement. RESULTS: Our system was constructed successfully and functioned correctly. CONCLUSION: In this pilot study we found this system efficient for the evaluation of microleakage of dental materials. PMID:24146673

  11. Toward objective and quantitative evaluation of imaging systems using images of phantoms

    SciTech Connect

    Gagne, Robert M.; Gallas, Brandon D.; Myers, Kyle J. [Center for Devices and Radiological Health, FDA, 12720 Twinbrook Parkway, Rockville, Maryland 20857 (United States)

    2006-01-15

    The use of imaging phantoms is a common method of evaluating image quality in the clinical setting. These evaluations rely on a subjective decision by a human observer with respect to the faintest detectable signal(s) in the image. Because of the variable and subjective nature of the human-observer scores, the evaluations manifest a lack of precision and a potential for bias. The advent of digital imaging systems with their inherent digital data provides the opportunity to use techniques that do not rely on human-observer decisions and thresholds. Using the digital data, signal-detection theory (SDT) provides the basis for more objective and quantitative evaluations which are independent of a human-observer decision threshold. In a SDT framework, the evaluation of imaging phantoms represents a 'signal-known-exactly/background-known-exactly' ('SKE/BKE') detection task. In this study, we compute the performance of prewhitening and nonprewhitening model observers in terms of the observer signal-to-noise ratio (SNR) for these 'SKE/BKE' tasks. We apply the evaluation methods to a number of imaging systems. For example, we use data from a laboratory implementation of digital radiography and from a full-field digital mammography system in a clinical setting. In addition, we make a comparison of our methods to human-observer scoring of a set of digital images of the CDMAM phantom available from the internet (EUREF--European Reference Organization). In the latter case, we show a significant increase in the precision of the quantitative methods versus the variability in the scores from human observers on the same set of images. As regards bias, the performance of a model observer estimated from a finite data set is known to be biased. In this study, we minimize the bias and estimate the variance of the observer SNR using statistical resampling techniques, namely, 'bootstrapping' and 'shuffling' of the data sets. Our methods provide objective and quantitative evaluation of imaging systems with increased precision and reduced bias.

  12. The quantitative evaluation of the correlation between the magnification and the visibility-contrast value

    NASA Astrophysics Data System (ADS)

    Okubo, Shohei; Shibata, Takayuki; Kodera, Yoshie

    2015-03-01

    Talbot-Lau interferometer, which consists of a conventional x-ray tube, an x-ray detector, and three gratings arranged between them, is a new x-ray imaging system using phase-contrast method for excellent visualization of soft tissue. So, it is expected to be applied to an imaging method for soft tissue in the medical field, such as mammograms. The visibility-contrast image, which is one of the reconstruction images using Talbot-Lau interferometer, is known that the visibility-contrast reflects reduction of coherence that is caused from the x-ray small-angle scattering and the x-ray refraction due to the object's structures. Both phenomena were not distinguished when we evaluated the visibility signal quantitatively before. However, we consider that we should distinguish both phenomena to evaluate it quantitatively. In this study, to evaluate how much the magnification affect the visibility signal, we investigated the variability rate of the visibility signal between the object-position in the height of 0 cm to 50 cm from the diffraction grating in each case of examining the scattering signal and the refraction signal. We measured the edge signal of glass sphere to examine the scattering signal and the internal signal of glass sphere and some kinds of sheet to examine the refraction signal. We can indicate the difference of the variability rate between the edge signal and the internal signal. We tried to propose the estimation method using magnification.

  13. A quantitative evaluation of effective shale content and its influence on electrical resistivity and permeability of reservoir rocks

    E-print Network

    Menon, Parayath Eravi Bhaskara

    1965-01-01

    A QUANTITATIVE EVALUATION OF EFFECTIVE SHALE CONTENT AND ITS INFLUENCE ON ELECTRICAL RESISTIVITY AND PERMEABILITY OF RESERVOIR ROCKS A Thesis By PARAYATH E. B. MENON Submitted to the Graduate College of Texas ASM University in Partial... fulfillment of the Requirements for the Degree of MASTER OF SCIENCE January, f965 Major Subject: Petroleum Engineering A QUANTITATIVE EVALUATION OF EFFECTIVE SHALE CONTENT AND ITS INFLUENCE ON ELECTRICAL RESISTIVITY AND PERMEABILITY OF RESERVOIR ROCKS...

  14. Quantitative evaluation of registration methods for atlas-based diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Wu, Xue; Eggebrecht, Adam T.; Culver, Joseph P.; Zhan, Yuxuan; Basevi, Hector; Dehghani, Hamid

    2013-06-01

    In Diffuse Optical Tomography (DOT), an atlas-based model can be used as an alternative to a subject-specific anatomical model for recovery of brain activity. The main step of the generation of atlas-based subject model is the registration of atlas model to the subject head. The accuracy of the DOT then relies on the accuracy of registration method. In this work, 11 registration methods are quantitatively evaluated. The registration method with EEG 10/20 systems with 19 landmarks and non-iterative point to point algorithm provides approximately 1.4 mm surface error and is considered as the most efficient registration method.

  15. An evaluation of four quantitative laboratory fume hood performance test methods

    E-print Network

    Woodrow, Lisa Michele

    1987-01-01

    AN EVAIIKTION OF HX3R QUAI~IVE BQKSRMRY HJME HOOD PERIORMANCE TEST MEIBDDS A Thesis Submitted to the Gradate College of Texas A&M University in partial fulfillment of the requirements for the degree of AUgUst 1987 Major Subject: Industrial... Hygiene AN EVALUATION OF FOUR QUANTITATIVE IABORATORY FUME HOOD PERFORMANCE TEST METHODS A Thesis Approved as to style and content by: Ri B. (Chair of Ccamrdttee) J. 4u s (~) J. er Calvin B. Parnell (~) . Kemb Bennett (Head of Department) August...

  16. Nondestructive Acoustic Imaging Techniques

    Microsoft Academic Search

    Volker Schmitz

    2002-01-01

    Acoustic imaging techniques are used in the field of nondestructive testing of technical components to measure defects such\\u000a as lack of side wall fusion or cracks in welded joints. Data acquisition is performed by a remote-controlled manipulator and\\u000a a PC for the mass storage of the high-frequency time-of-flight data at each probe position. The quality of the acoustic images\\u000a and

  17. Experimental Evaluation of Quantitative Diagnosis Technique for Hepatic Fibrosis Using Ultrasonic Phantom

    NASA Astrophysics Data System (ADS)

    Koriyama, Atsushi; Yasuhara, Wataru; Hachiya, Hiroyuki

    2012-07-01

    Since clinical diagnosis using ultrasonic B-mode images depends on the skill of the doctor, the realization of a quantitative diagnosis method using an ultrasound echo signal is highly required. We have been investigating a quantitative diagnosis technique, mainly for hepatic disease. In this paper, we present the basic experimental evaluation results on the accuracy of the proposed quantitative diagnosis technique for hepatic fibrosis by using a simple ultrasonic phantom. As a region of interest crossed on the boundary between two scatterer areas with different densities in a phantom, we can simulate the change of the echo amplitude distribution from normal tissue to fibrotic tissue in liver disease. The probability density function is well approximated by our fibrosis distribution model that is a mixture of normal and fibrotic tissue. The fibrosis parameters of the amplitude distribution model can be estimated relatively well at a mixture rate from 0.2 to 0.6. In the inversion processing, the standard deviation of the estimated fibrosis results at mixture ratios of less than 0.2 and larger than 0.6 are relatively large. Although the probability density is not large at high amplitude, the estimated variance ratio and mixture rate of the model are strongly affected by higher amplitude data.

  18. NON-DESTRUCTIVE SOIL CARBON ANALYZER.

    SciTech Connect

    Wielopolski, Lucian; Hendrey, G.; Orion, I.; Prior, S.; Rogers, H.; Runion, B.; Torbert, A.

    2004-02-01

    This report describes the feasibility, calibration, and safety considerations of a non-destructive, in situ, quantitative, volumetric soil carbon analytical method based on inelastic neutron scattering (INS). The method can quantify values as low as 0.018 gC/cc, or about 1.2% carbon by weight with high precision under the instrument's configuration and operating conditions reported here. INS is safe and easy to use, residual soil activation declines to background values in under an hour, and no radiological requirements are needed for transporting the instrument. The labor required to obtain soil-carbon data is about 10-fold less than with other methods, and the instrument offers a nearly instantaneous rate of output of carbon-content values. Furthermore, it has the potential to quantify other elements, particularly nitrogen. New instrumentation was developed in response to a research solicitation from the U.S. Department of Energy (DOE LAB 00-09 Carbon Sequestration Research Program) supporting the Terrestrial Carbon Processes (TCP) program of the Office of Science, Biological and Environmental Research (BER). The solicitation called for developing and demonstrating novel techniques for quantitatively measuring changes in soil carbon. The report includes raw data and analyses of a set of proof-of-concept, double-blind studies to evaluate the INS approach in the first phase of developing the instrument. Managing soils so that they sequester massive amounts of carbon was suggested as a means to mitigate the atmospheric buildup of anthropogenic CO{sub 2}. Quantifying changes in the soils' carbon stocks will be essential to evaluating such schemes and documenting their performance. Current methods for quantifying carbon in soil by excavation and core sampling are invasive, slow, labor-intensive and locally destroy the system being observed. Newly emerging technologies, such as Laser Induced Breakdown Spectroscopy and Near-Infrared Spectroscopy, offer soil-carbon analysis; however, these also are invasive and destructive techniques. The INS approach permits quantification in a relatively large volume of soil without disrupting the measurement site. The technique is very fast and provides nearly instantaneous results thereby reducing the cost, and speeding up the rate of analysis. It also has the potential to cover large areas in a mobile scanning mode. These capabilities will significantly advance the tracking carbon sequestration and offer a tool for research in agronomy, forestry, soil ecology and biogeochemistry.

  19. Wavelet-Based Image Registration and Segmentation Framework for the Quantitative Evaluation of Hydrocephalus

    PubMed Central

    Luo, Fan; Evans, Jeanette W.; Linney, Norma C.; Schmidt, Matthias H.; Gregson, Peter H.

    2010-01-01

    Hydrocephalus, characterized by increased fluid in the cerebral ventricles, is traditionally evaluated by a visual assessment of serial CT scans. The complex shape of the ventricular system makes accurate visual comparison of CT scans difficult. The current research developed a quantitative method to measure the change in cerebral ventricular volume over time. Key elements of the developed framework are: adaptive image registration based on mutual information and wavelet multiresolution analysis; adaptive segmentation with novel feature extraction based on the Dual-Tree Complex Wavelet Transform; volume calculation. The framework, when tested on physical phantoms, had an error of 2.3%. When validated on clinical cases, results showed that cases deemed to be normal/stable had a calculated volume change less than 5%. Those with progressive/treated hydrocephalus had a calculated change greater than 20%. These findings indicate that the framework is reasonable and has potential for development as a tool in the evaluation of hydrocephalus. PMID:20414346

  20. Quantitative Evaluation of the Total Magnetic Moments of Colloidal Magnetic Nanoparticles: A Kinetics-based Method.

    PubMed

    Liu, Haiyi; Sun, Jianfei; Wang, Haoyao; Wang, Peng; Song, Lina; Li, Yang; Chen, Bo; Zhang, Yu; Gu, Ning

    2015-06-01

    A kinetics-based method is proposed to quantitatively characterize the collective magnetization of colloidal magnetic nanoparticles. The method is based on the relationship between the magnetic force on a colloidal droplet and the movement of the droplet under a gradient magnetic field. Through computational analysis of the kinetic parameters, such as displacement, velocity, and acceleration, the magnetization of colloidal magnetic nanoparticles can be calculated. In our experiments, the values measured by using our method exhibited a better linear correlation with magnetothermal heating, than those obtained by using a vibrating sample magnetometer and magnetic balance. This finding indicates that this method may be more suitable to evaluate the collective magnetism of colloidal magnetic nanoparticles under low magnetic fields than the commonly used methods. Accurate evaluation of the magnetic properties of colloidal nanoparticles is of great importance for the standardization of magnetic nanomaterials and for their practical application in biomedicine. PMID:25943076

  1. Quantitative evaluation of noise reduction and vesselness filters for liver vessel segmentation on abdominal CTA images

    NASA Astrophysics Data System (ADS)

    Luu, Ha Manh; Klink, Camiel; Moelker, Adriaan; Niessen, Wiro; van Walsum, Theo

    2015-05-01

    Liver vessel segmentation in CTA images is a challenging task, especially in the case of noisy images. This paper investigates whether pre-filtering improves liver vessel segmentation in 3D CTA images. We introduce a quantitative evaluation of several well-known filters based on a proposed liver vessel segmentation method on CTA images. We compare the effect of different diffusion techniques i.e. Regularized Perona–Malik, Hybrid Diffusion with Continuous Switch and Vessel Enhancing Diffusion as well as the vesselness approaches proposed by Sato, Frangi and Erdt. Liver vessel segmentation of the pre-processed images is performed using a histogram-based region grown with local maxima as seed points. Quantitative measurements (sensitivity, specificity and accuracy) are determined based on manual landmarks inside and outside the vessels, followed by T-tests for statistic comparisons on 51 clinical CTA images. The evaluation demonstrates that all the filters make liver vessel segmentation have a significantly higher accuracy than without using a filter (p??

  2. Development and evaluation of an improved quantitative 90Y bremsstrahlung SPECT method

    PubMed Central

    Rong, Xing; Du, Yong; Ljungberg, Michael; Rault, Erwann; Vandenberghe, Stefaan; Frey, Eric C.

    2012-01-01

    Purpose: Yttrium-90 (90Y) is one of the most commonly used radionuclides in targeted radionuclide therapy (TRT). Since it decays with essentially no gamma photon emissions, surrogate radionuclides (e.g., 111In) or imaging agents (e.g., 99mTc MAA) are typically used for treatment planning. It would, however, be useful to image 90Y directly in order to confirm that the distributions measured with these other radionuclides or agents are the same as for the 90Y labeled agents. As a result, there has been a great deal of interest in quantitative imaging of 90Y bremsstrahlung photons using single photon emission computed tomography (SPECT) imaging. The continuous and broad energy distribution of bremsstrahlung photons, however, imposes substantial challenges on accurate quantification of the activity distribution. The aim of this work was to develop and evaluate an improved quantitative 90Y bremsstrahlung SPECT reconstruction method appropriate for these imaging applications. Methods: Accurate modeling of image degrading factors such as object attenuation and scatter and the collimator-detector response is essential to obtain quantitatively accurate images. All of the image degrading factors are energy dependent. Thus, the authors separated the modeling of the bremsstrahlung photons into multiple categories and energy ranges. To improve the accuracy, the authors used a bremsstrahlung energy spectrum previously estimated from experimental measurements and incorporated a model of the distance between 90Y decay location and bremsstrahlung emission location into the SIMIND code used to generate the response functions and kernels used in the model. This improved Monte Carlo bremsstrahlung simulation was validated by comparison to experimentally measured projection data of a 90Y line source. The authors validated the accuracy of the forward projection model for photons in the various categories and energy ranges using the validated Monte Carlo (MC) simulation method. The forward projection model was incorporated into an iterative ordered subsets-expectation maximization (OS-EM) reconstruction code to allow for quantitative SPECT reconstruction. The resulting code was validated using both a physical phantom experiment with spherical objects in a warm background and a realistic anatomical phantom simulation. In the physical phantom study, the authors evaluated the method in terms of quantitative accuracy of activity estimates in the spheres; in the simulation study, the authors evaluated the accuracy and precision of activity estimates from various organs and compared them to results from a previously proposed method. Results: The authors demonstrated excellent agreement between the experimental measurement and Monte Carlo simulation. In the XCAT phantom simulation, the proposed method achieved much better accuracy in the modeling (error in photon counts was ?1.1?%) compared to a previously proposed method (errors were more than 20??%); the quantitative accuracy of activity estimates was excellent for all organs (errors were from ?1.6?% to 11.9?%) and comparable to previously published results for 131I using the same collimator. Conclusions: The proposed 90Y bremsstrahlung SPECT reconstruction method provided very accurate estimates of organ activities, with accuracies approaching those previously observed for 131I. The method may be useful in verifying organ doses for targeted radionuclide therapy using 90Y. PMID:22559605

  3. Quantitative image quality evaluation of MR images using perceptual difference models.

    PubMed

    Miao, Jun; Huo, Donglai; Wilson, David L

    2008-06-01

    The authors are using a perceptual difference model (Case-PDM) to quantitatively evaluate image quality of the thousands of test images which can be created when optimizing fast magnetic resonance (MR) imaging strategies and reconstruction techniques. In this validation study, they compared human evaluation of MR images from multiple organs and from multiple image reconstruction algorithms to Case-PDM and similar models. The authors found that Case-PDM compared very favorably to human observers in double-stimulus continuous-quality scale and functional measurement theory studies over a large range of image quality. The Case-PDM threshold for nonperceptible differences in a 2-alternative forced choice study varied with the type of image under study, but was approximately 1.1 for diffuse image effects, providing a rule of thumb. Ordering the image quality evaluation models, we found in overall Case-PDM approximately IDM (Sarnoff Corporation) approximately SSIM [Wang et al. IEEE Trans. Image Process. 13, 600-612 (2004)] > mean squared error NR [Wang et al. (2004) (unpublished)] > DCTune (NASA) > IQM (MITRE Corporation). The authors conclude that Case-PDM is very useful in MR image evaluation but that one should probably restrict studies to similar images and similar processing, normally not a limitation in image reconstruction studies. PMID:18649487

  4. Quantitative image quality evaluation of MR images using perceptual difference models

    PubMed Central

    Miao, Jun; Huo, Donglai; Wilson, David L.

    2008-01-01

    The authors are using a perceptual difference model (Case-PDM) to quantitatively evaluate image quality of the thousands of test images which can be created when optimizing fast magnetic resonance (MR) imaging strategies and reconstruction techniques. In this validation study, they compared human evaluation of MR images from multiple organs and from multiple image reconstruction algorithms to Case-PDM and similar models. The authors found that Case-PDM compared very favorably to human observers in double-stimulus continuous-quality scale and functional measurement theory studies over a large range of image quality. The Case-PDM threshold for nonperceptible differences in a 2-alternative forced choice study varied with the type of image under study, but was ?1.1 for diffuse image effects, providing a rule of thumb. Ordering the image quality evaluation models, we found in overall Case-PDM ? IDM (Sarnoff Corporation) ? SSIM [Wang et al. IEEE Trans. Image Process. 13, 600–612 (2004)] > mean squared error ? NR [Wang et al. (2004) (unpublished)] > DCTune (NASA) > IQM (MITRE Corporation). The authors conclude that Case-PDM is very useful in MR image evaluation but that one should probably restrict studies to similar images and similar processing, normally not a limitation in image reconstruction studies. PMID:18649487

  5. Application of a quantitative carrier test to evaluate microbicides against mycobacteria.

    PubMed

    Springthorpe, V Susan; Sattar, Syed A

    2007-01-01

    Microbicides for reprocessing heat-sensitive medical devices, such as flexible endoscopes, must be mycobactericidal to reduce the risk of nosocomial infections. Suspension test methods currently used for efficacy evaluation lack the stringency required for assessing inactivation of mycobacteria on surfaces. The quantitative carrier test method reported here is based on mycobacteria-contaminated reference carrier disks of brushed stainless steel. Each disk was contaminated with 10 microL of a suspension of Mycobacterium terrae containing a soil load. Each disk with a dried inoculum was placed in a glass or Teflon vial, and then overlaid with 50 microL of the test formulation or 50 microL saline for the control carriers. Five test and 3 control disks were used in each run. At the end of the contact time, each vial received 9.95 mL neutralizer solution with 0.1% Tween-80 to stop the reaction and perform the initial microbicide dilution. The inoculum was eluted by mixing on a Vortex mixer for 60 s, and the eluates and saline used to subsequently wash the vials and the funnels were membrane-filtered. Filters were placed on plates of Middlebrook 7H11 agar and incubated at 37 degrees C for at least 30 days before colonies were counted and log10 reductions were calculated in colony-forming units. Tests with a range of commercially available products, having claims against mycobacteria, or believed to be broad-spectrum microbicides, showed that the method gave reproducible results. Products used included oxidizing agents (sodium hypochlorite and an iodophore), a phenolic, a quaternary ammonium compound, and ortho-phthalaldehyde. This method represents a much more realistic evaluation than the currently used quantitative suspension test method for the evaluation of mycobactericidal formulations for registration and, when performed at different product concentrations, allows an assessment of any safety margin or risks in using the test formulation in the field. PMID:17580635

  6. Utilizing Optical Coherence Tomography in the Nondestructive and Noncontact Measurement of Egg Shell Thickness

    PubMed Central

    2014-01-01

    The goal of this study was to measure the thickness of egg shells without any contact and by utilizing a nondestructive method that sends infrared light beam on the egg. We obtain measurement resolutions on the order of 7??m up to a penetration depth of 1.7?mm from the actual surface of the egg shell. The measurement results we obtained show that optical coherence tomography can be used to accurately determine the egg shell thickness. Scanning the light beam over the surface allows for measuring the egg profile and monitoring the variations of shell thickness. Since this information gives a quantitative value for the uniformity of the egg shell structure, we anticipate that optical coherence tomography may be used in the quantitative evaluation of egg quality in in-line automated inspection systems. PMID:25133208

  7. Improvement of interfacial adhesion and nondestructive damage evaluation for plasma-treated PBO and Kevlar fibers/epoxy composites using micromechanical techniques and surface wettability.

    PubMed

    Park, Joung-Man; Kim, Dae-Sik; Kim, Sung-Ryong

    2003-08-15

    Comparison of interfacial properties and microfailure mechanisms of oxygen-plasma treated poly(p-phenylene-2,6-benzobisoxazole (PBO, Zylon) and poly(p-phenylene terephthalamide) (PPTA, Kevlar) fibers/epoxy composites were investigated using a micromechanical technique and nondestructive acoustic emission (AE). The interfacial shear strength (IFSS) and work of adhesion, Wa, of PBO or Kevlar fiber/epoxy composites increased with oxygen-plasma treatment, due to induced hydrogen and covalent bondings at their interface. Plasma-treated Kevlar fiber showed the maximum critical surface tension and polar term, whereas the untreated PBO fiber showed the minimum values. The work of adhesion and the polar term were proportional to the IFSS directly for both PBO and Kevlar fibers. The microfibril fracture pattern of two plasma-treated fibers appeared obviously. Unlike in slow cooling, in rapid cooling, case kink band and kicking in PBO fiber appeared, whereas buckling in the Kevlar fiber was observed mainly due to compressive and residual stresses. Based on the propagation of microfibril failure toward the core region, the number of AE events for plasma-treated PBO and Kevlar fibers increased significantly compared to the untreated case. The results of nondestructive AE were consistent with microfailure modes. PMID:16256662

  8. Nondestructive testing with thermography

    NASA Astrophysics Data System (ADS)

    Ibarra-Castanedo, Clemente; Tarpani, José Ricardo; Maldague, Xavier P. V.

    2013-11-01

    Thermography is a nondestructive testing (NDT) technique based on the principle that two dissimilar materials, i.e., possessing different thermo-physical properties, would produce two distinctive thermal signatures that can be revealed by an infrared sensor, such as a thermal camera. The fields of NDT applications are expanding from classical building or electronic components monitoring to more recent ones such as inspection of artworks or composite materials. Furthermore, thermography can be conveniently used as a didactic tool for physics education in universities given that it provides the possibility of visualizing fundamental principles, such as thermal physics and mechanics among others.

  9. Nondestructive material characterization

    DOEpatents

    Deason, Vance A. (Idaho Falls, ID); Johnson, John A. (Idaho Falls, ID); Telschow, Kenneth L. (Idaho Falls, ID)

    1991-01-01

    A method and apparatus for nondestructive material characterization, such as identification of material flaws or defects, material thickness or uniformity and material properties such as acoustic velocity. The apparatus comprises a pulsed laser used to excite a piezoelectric (PZ) transducer, which sends acoustic waves through an acoustic coupling medium to the test material. The acoustic wave is absorbed and thereafter reflected by the test material, whereupon it impinges on the PZ transducer. The PZ transducer converts the acoustic wave to electrical impulses, which are conveyed to a monitor.

  10. An evaluation of genetically encoded FRET-based biosensors for quantitative metabolite analyses in vivo.

    PubMed

    Moussa, Roland; Baierl, Anna; Steffen, Victoria; Kubitzki, Tina; Wiechert, Wolfgang; Pohl, Martina

    2014-12-10

    A broad range of genetically-encoded fluorescence biosensors has been developed, allowing the detection of signaling intermediates and metabolites in real time. Many of these biosensors are based on Foerster Resonance Energy Transfer (FRET). The two biosensors of the well-known "Venus-flytrap" type exemplarily studied in this work are composed of a central sugar binding protein flanked by two green fluorescent protein derivatives, namely ECFP as well as Citrine and EYFP, respectively. In order to evaluate FRET-based biosensors as an in vivo tool for quantitative metabolite analyses, we have thoroughly studied the effects of pH, buffer salts, ionic strength, temperature and several intracellular metabolites on the signal intensity of both biosensors and both fluorescence proteins. Almost all micro-environmental variations led to considerably different FRET signals, because either the fluorescent proteins or the metabolite binding domains were affected by the tested parameters. This resulted not only in altered FRET ratios between the apo state and the saturated state but also in significant shifts of the apparent binding constant. This underlines the necessity of careful controls in order to allow reliable quantitative measurements in vivo. PMID:25107505

  11. Quantitative evaluation of hidden defects in cast iron components using ultrasound activated lock-in vibrothermography

    SciTech Connect

    Montanini, R.; Freni, F. [Department of Industrial Chemistry and Materials Engineering, University of Messina, Contrada di Dio, 98166 Messina (Italy); Rossi, G. L. [Department of Industrial Engineering, University of Perugia, Via Duranti 1, 06125 Perugia (Italy)

    2012-09-15

    This paper reports one of the first experimental results on the application of ultrasound activated lock-in vibrothermography for quantitative assessment of buried flaws in complex cast parts. The use of amplitude modulated ultrasonic heat generation allowed selective response of defective areas within the part, as the defect itself is turned into a local thermal wave emitter. Quantitative evaluation of hidden damages was accomplished by estimating independently both the area and the depth extension of the buried flaws, while x-ray 3D computed tomography was used as reference for sizing accuracy assessment. To retrieve flaw's area, a simple yet effective histogram-based phase image segmentation algorithm with automatic pixels classification has been developed. A clear correlation was found between the thermal (phase) signature measured by the infrared camera on the target surface and the actual mean cross-section area of the flaw. Due to the very fast cycle time (<30 s/part), the method could potentially be applied for 100% quality control of casting components.

  12. [Quantitative evaluation of pilot workload influence on functional stability and occupational health of pilots (scientific and practical aspects)].

    PubMed

    Vartbaronov, R A; Khomenko, M N; Bondarenko, R A

    2000-01-01

    Based on early concepts of quantitative evaluation of pilotage overload influence on pilot, the authors justified principles and criteria for biometric characterization of overload parameters and human response concerning the problem of manoeuvreable flight and pilot's occupational health preservation. The article presents quantitative dependencies between various overload parameters, occupational conditions and -effects, considering risk of disorders that determine potential unreliability of pilot in manoeuvreable flight and possible cumulative effects from dose viewpoint. PMID:10881541

  13. Modelling the quantitative evaluation of soil nutrient supply, nutrient use efficiency, and fertilizer requirements of wheat in India

    Microsoft Academic Search

    H. Pathak; P. K. Aggarwal; R. P. Roetter; N. Kalra; S. K. Bandyopadhaya; S. Prasad; H. Van Keulen

    2003-01-01

    Wheat yields in many parts of India are stagnant. The main reason forthis is conventional blanket fertilizer recommendation, lower fertilizer useefficiency, and imbalanced use of fertilizers. Estimation of fertilizerrequirements based on quantitative approaches can assist in improving wheatyields and increasing nutrient use efficiency. We used the QUEFTS (QUantitativeEvaluation of Fertility of Tropical Soils) model for estimation of nitrogen(N),phosphorus (P), and

  14. Field evaluation of a quantitative polymerase chain reaction assay for Mycoplasma hyorhinis.

    PubMed

    Clavijo, Maria J; Oliveira, Simone; Zimmerman, Jeffrey; Rendahl, Aaron; Rovira, Albert

    2014-11-01

    Mycoplasma hyorhinis has emerged as an important cause of systemic disease in nursery pigs. However, this bacterium can also be found in the upper respiratory tract of healthy swine. The current study describes the development of a quantitative polymerase chain reaction assay for the detection of M. hyorhinis and the evaluation of the assay in both disease diagnosis and disease surveillance using a large number of field samples. The analytical sensitivity was estimated to be 12 genome equivalents/?l. The assay was highly specific, detecting all 25 M. hyorhinis isolates tested and none of the 19 nontarget species tested. Assay repeatability was evaluated by testing different matrices spiked with known amounts of M. hyorhinis. Overall, assessment of the repeatability of the assay showed suitable precision within and between runs for all matrices. The coefficient of variation ranged from 10% to 24%. Mycoplasma hyorhinis DNA was detected in 48% of samples (pericardium, pleura, joints, nasal cavity, and lungs) from pigs with systemic disease. Mycoplasma hyorhinis was detected in nasal (92%) and oropharyngeal swabs (66%), as well as in oral fluids (100%). Potential uses of this tool involve the characterization of the prevalence of this pathogen in swine herds as well as bacterial quantification to evaluate intervention efficacy. PMID:25319032

  15. Quantitative Evaluation and Selection of Reference Genes in a Rat Model of Extended Liver Resection

    PubMed Central

    Xing, Wei; Deng, Meihong; Zhang, Jinyan; Huang, Hai; Dirsch, Olaf; Dahmen, Uta

    2009-01-01

    Partial hepatectomy (PHx) is a frequently used experimental model for the study of liver regeneration. Real-time quantitative PCR (qPCR) has become the one of the methods of choice for expression profiling of selected genes in order to elucidate the regulation of liver function and regeneration. The expression of five commonly used housekeeping genes (HKGs; Alb, UBC, Hprt, Ywhaz, and GAPDH) were evaluated by qPCR in 70% and 90% rat PHx model at 1, 2, and 7 d after PHx. We set up a closely controlled qPCR procedure validating each critical step and the gene expression stability was statistically evaluated by linear regression and analysis of variance. Our results showed the HKG best suited for the evaluation of gene expression in the extended 90% PHx model is Hprt. The amplification of an HKG can be omitted when the same amount of cDNA from all samples is introduced into the amplification reaction. Determination of cDNA concentration employing the bioanalyzer proved to be an easy and reproducible approach. Using this technique the potential regulation of the transcription level of the HKG in response to the experimental condition tested or the stability of a housekeeping gene becomes irrelevant. PMID:19503622

  16. Noninvasive Quantitative Evaluation of the Dentin Layer during Dental Procedures Using Optical Coherence Tomography

    PubMed Central

    Sinescu, Cosmin; Negrutiu, Meda Lavinia; Bradu, Adrian; Duma, Virgil-Florin; Podoleanu, Adrian Gh.

    2015-01-01

    A routine cavity preparation of a tooth may lead to opening the pulp chamber. The present study evaluates quantitatively, in real time, for the first time to the best of our knowledge, the drilled cavities during dental procedures. An established noninvasive imaging technique, Optical Coherence Tomography (OCT), is used. The main scope is to prevent accidental openings of the dental pulp chamber. Six teeth with dental cavities have been used in this ex vivo study. The real time assessment of the distances between the bottom of the drilled cavities and the top of the pulp chamber was performed using an own assembled OCT system. The evaluation of the remaining dentin thickness (RDT) allowed for the positioning of the drilling tools in the cavities in relation to the pulp horns. Estimations of the safe and of the critical RDT were made; for the latter, the opening of the pulp chamber becomes unavoidable. Also, by following the fractures that can occur when the extent of the decay is too large, the dentist can decide upon the right therapy to follow, endodontic or conventional filling. The study demonstrates the usefulness of OCT imaging in guiding such evaluations during dental procedures.

  17. Quantitative evaluation of firms offering remote sensing services for geological exploration

    SciTech Connect

    Mannes, L.V. Jr.

    1987-08-01

    In a totally non-regulated industry, such as remote sensing, literally any individual or firm can make extravagant claims and offer expert services with impunity. Most such expert remote sensing services consist of inadequate and inappropriate lineament analyses or image classifications that are near-worthless, rather than products with real exploration value, such as the generation of improved geological maps or the delineation of geochemical and geobotanical anomalies. There is no legal, nor even a self-policing mechanism, to assure the competence of practitioners in the industry - which is why so many remote sensing specialists with little or no geological training offer geological exploration services. In this Caveat Emptor (let the buyer beware) environments, exploration firms must carefully weigh the level of competence, quality of products and services, reputation, ethics, claims of efficacy, guarantees, and so forth, of all firms under consideration, before letting any contrast. Unfortunately, the capabilities of remote sensing firms being inherently unequal, the conventional approach of retaining these services solely on the basis of lowest bid is an excellent method to assure the depletion of precious budgetary resources with little or no financial return. The simple and practical quantitative method presented for evaluating remote sensing firms presented here gives the explorationist an impartial mechanism for ensuring the very highest quality professional services. The quantitative methodology is easily modified for the unique circumstances of individual firms; furthermore, this method can be adapted for the evaluation of other exploration services as well. In this difficult economic environment, neither explorationists nor the many quality service firms can afford the luxury of inadvertently subsidizing charlatanry.

  18. Quantitative evaluation of interaction force between functional groups in protein and polymer brush surfaces.

    PubMed

    Sakata, Sho; Inoue, Yuuki; Ishihara, Kazuhiko

    2014-03-18

    To understand interactions between polymer surfaces and different functional groups in proteins, interaction forces were quantitatively evaluated by force-versus-distance curve measurements using atomic force microscopy with a functional-group-functionalized cantilever. Various polymer brush surfaces were systematically prepared by surface-initiated atom transfer radical polymerization as well-defined model surfaces to understand protein adsorption behavior. The polymer brush layers consisted of phosphorylcholine groups (zwitterionic/hydrophilic), trimethylammonium groups (cationic/hydrophilic), sulfonate groups (anionic/hydrophilic), hydroxyl groups (nonionic/hydrophilic), and n-butyl groups (nonionic/hydrophobic) in their side chains. The interaction forces between these polymer brush surfaces and different functional groups (carboxyl groups, amino groups, and methyl groups, which are typical functional groups existing in proteins) were quantitatively evaluated by force-versus-distance curve measurements using atomic force microscopy with a functional-group-functionalized cantilever. Furthermore, the amount of adsorbed protein on the polymer brush surfaces was quantified by surface plasmon resonance using albumin with a negative net charge and lysozyme with a positive net charge under physiological conditions. The amount of proteins adsorbed on the polymer brush surfaces corresponded to the interaction forces generated between the functional groups on the cantilever and the polymer brush surfaces. The weakest interaction force and least amount of protein adsorbed were observed in the case of the polymer brush surface with phosphorylcholine groups in the side chain. On the other hand, positive and negative surfaces generated strong forces against the oppositely charged functional groups. In addition, they showed significant adsorption with albumin and lysozyme, respectively. These results indicated that the interaction force at the functional group level might be a suitable parameter for understanding protein adsorption. PMID:24564418

  19. A quantitative evaluation of cell migration by the phagokinetic track motility assay.

    PubMed

    Nogalski, Maciej T; Chan, Gary C T; Stevenson, Emily V; Collins-McMillen, Donna K; Yurochko, Andrew D

    2012-01-01

    Cellular motility is an important biological process for both unicellular and multicellular organisms. It is essential for movement of unicellular organisms towards a source of nutrients or away from unsuitable conditions, as well as in multicellular organisms for tissue development, immune surveillance and wound healing, just to mention a few roles(1,2,3). Deregulation of this process can lead to serious neurological, cardiovascular and immunological diseases, as well as exacerbated tumor formation and spread(4,5). Molecularly, actin polymerization and receptor recycling have been shown to play important roles in creating cellular extensions (lamellipodia), that drive the forward movement of the cell(6,7,8). However, many biological questions about cell migration remain unanswered. The central role for cellular motility in human health and disease underlines the importance of understanding the specific mechanisms involved in this process and makes accurate methods for evaluating cell motility particularly important. Microscopes are usually used to visualize the movement of cells. However, cells move rather slowly, making the quantitative measurement of cell migration a resource-consuming process requiring expensive cameras and software to create quantitative time-lapsed movies of motile cells. Therefore, the ability to perform a quantitative measurement of cell migration that is cost-effective, non-laborious, and that utilizes common laboratory equipment is a great need for many researchers. The phagokinetic track motility assay utilizes the ability of a moving cell to clear gold particles from its path to create a measurable track on a colloidal gold-coated glass coverslip(9,10). With the use of freely available software, multiple tracks can be evaluated for each treatment to accomplish statistical requirements. The assay can be utilized to assess motility of many cell types, such as cancer cells(11,12), fibroblasts(9), neutrophils(13), skeletal muscle cells(14), keratinocytes(15), trophoblasts(16), endothelial cells(17), and monocytes(10,18-22). The protocol involves the creation of slides coated with gold nanoparticles (Au°) that are generated by a reduction of chloroauric acid (Au(3+)) by sodium citrate. This method was developed by Turkevich et al. in 1951(23) and then improved in the 1970s by Frens et al.(24,25). As a result of this chemical reduction step, gold particles (10-20 nm in diameter) precipitate from the reaction mixture and can be applied to glass coverslips, which are then ready for use in cellular migration analyses(9,26,27). In general, the phagokinetic track motility assay is a quick, quantitative and easy measure of cellular motility. In addition, it can be utilized as a simple high-throughput assay, for use with cell types that are not amenable to time-lapsed imaging, as well as other uses depending on the needs of the researcher. Together, the ability to quantitatively measure cellular motility of multiple cell types without the need for expensive microscopes and software, along with the use of common laboratory equipment and chemicals, make the phagokinetic track motility assay a solid choice for scientists with an interest in understanding cellular motility. PMID:23242175

  20. A Monte Carlo and physical phantom evaluation of quantitative In-111 SPECT

    NASA Astrophysics Data System (ADS)

    He, Bin; Du, Yong; Song, Xiyun; Segars, W. Paul; Frey, Eric C.

    2005-09-01

    Accurate estimation of the 3D in vivo activity distribution is important for dose estimation in targeted radionuclide therapy (TRT). Although SPECT can potentially provide such estimates, SPECT without compensation for image degrading factors is not quantitatively accurate. In this work, we evaluated quantitative SPECT (QSPECT) reconstruction methods that include compensation for various physical effects. Experimental projection data were obtained using a GE VH/Hawkeye system and an RSD torso phantom. Known activities of In-111 chloride were placed in the lungs, liver, heart, background and two spherical compartments with inner diameters of 22 mm and 34 mm. The 3D NCAT phantom with organ activities based on clinically derived In-111 ibritumomab tiuxetan data was used for the Monte Carlo (MC) simulation studies. Low-noise projection data were simulated using previously validated MC simulation methods. Fifty sets of noisy projections with realistic count levels were generated. Reconstructions were performed using the OS-EM algorithm with various combinations of attenuation (A), scatter (S), geometric response (G), collimator-detector response (D) and partial volume compensation (PVC). The QSPECT images from the various combinations of compensations were evaluated in terms of the accuracy and precision of the estimates of the total activity in each organ. For experimental data, the errors in organ activities for ADS and PVC compensation were less than 6.5% except the smaller sphere (-11.9%). For the noisy simulated data, the errors in organ activity for ADS compensation were less than 5.5% except the lungs (20.9%) and blood vessels (15.2%). Errors for other combinations of compensations were significantly (A, AS) or somewhat (AGS) larger. With added PVC, the error in the organ activities improved slightly except for the lungs (11.5%) and blood vessels (3.6%) where the improvement was more substantial. The standard deviation/mean ratios were all less than 1.5%. We conclude that QSPECT methods with appropriate compensations provided accurate In-111 organ activity estimates. For the collimator used, AGS was almost as good as ADS and may be preferable due to the reduced reconstruction time. PVC was important for small structures such as tumours or for organs in close proximity to regions with high activity. The improved quantitative accuracy from QSPECT methods has the potential for improving organ dose estimations in TRT.

  1. Thermal Nondestructive Evaluation Report: Inspection of the Refurbished Manipulator Arm System in the Manipulator Development Facility at Johnson Space Center 10-12 January 2001

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott

    2002-01-01

    On 4 December 2002, a failure of the Refurbished Manipulator Arm System (RMAS) occurred in the Manipulator Development Facility (MDF) at Johnson Space Center. When the Test Director commanded a should pitch maneuver to lift the arm from its payload bay pedestal, the yaw controls failed. This, coupled with a gravitational forces (due to the angle of the shoulder joint with respect to vertical), resulted in uncontrolled arm motion. The shoulder yaw joint moved approximately 20 degrees, causing the extended arm to strike and severely damage the port side MDF catwalk handrails. The arm motion stopped after impact with the handrails. On 10-12 January 2001, inspections were performed on the port face of the lower and upper arms of the RMAS using a infrared thermography developed at Langley Research Center. This paper presents the results of those nondestructive inspections and provides a complete description of the anomalies found and their locations.

  2. Evaluation of the veracity of one work by the artist Di Cavalcanti through non-destructive techniques: XRF, imaging and brush stroke analysis

    NASA Astrophysics Data System (ADS)

    Kajiya, E. A. M.; Campos, P. H. O. V.; Rizzutto, M. A.; Appoloni, C. R.; Lopes, F.

    2014-02-01

    This paper presents systematic studies and analysis that contributed to the identification of the forgery of a work by the artist Emiliano Augusto Cavalcanti de Albuquerque e Melo, known as Di Cavalcanti. The use of several areas of expertise such as brush stroke analysis ("pinacologia"), applied physics, and art history resulted in an accurate diagnosis for ascertaining the authenticity of the work entitled "Violeiro" (1950). For this work we used non-destructive methods such as techniques of infrared, ultraviolet, visible and tangential light imaging combined with chemical analysis of the pigments by portable X-Ray Fluorescence (XRF) and graphic gesture analysis. Each applied method of analysis produced specific information that made possible the identification of materials and techniques employed and we concluded that this work is not consistent with patterns characteristic of the artist Di Cavalcanti.

  3. Non-destructive evaluation of the effects of combined bisphosphonate and photodynamic therapy on bone strain in metastatic vertebrae using image registration.

    PubMed

    Hojjat, Seyed-Parsa; Won, Emily; Hardisty, Michael R; Akens, Margarete K; Wise-Milestone, Lisa M; Whyne, Cari M

    2011-11-01

    Skeletal metastases most frequently affect the vertebral column and may lead to severe consequences including fracture. Clinical management of skeletal metastases often utilizes a multimodal treatment approach, including bisphosphonates (BPs). Previous work has demonstrated the synergistic potential of photodynamic therapy (PDT) in combination with BP in treating osteolytic disease through structural, histologic, and destructive mechanical testing analyses. Recent work has developed and validated image-based methods that may be used to non-destructively determine mechanical stability in whole bones, and enable their use for additional (i.e. histologic) analysis. In this work we use an intensity-based 3D image registration technique to compare the strain patterns throughout untreated control and BP + PDT treated rnu/rnu rat spinal motion segments with osteolytic metastases. It was hypothesized that the combination treatment will reduce average and maximum strain values and restore the pattern of strain to that of healthy vertebrae. Mean, median, and 90th percentile strains in the control group were significantly higher than the treatment group. High strain areas in both groups were observed around the endplates; in the control group, large areas of high strains were also observed around the lesions and adjacent to the dorsal wall. Absence of high strains adjacent to the dorsal wall (similar to healthy vertebrae) may correspond to a reduced risk of burst fracture following BP + PDT therapy. This study demonstrates the application of non-destructive image analysis to quantify the positive mechanical effects of combined BP + PDT treatment in the metastatic spine. PMID:21818534

  4. Evaluation of quantitative PCR combined with PMA treatment for molecular assessment of microbial water quality.

    PubMed

    Gensberger, Eva Theres; Polt, Marlies; Konrad-Köszler, Marianne; Kinner, Paul; Sessitsch, Angela; Kosti?, Tanja

    2014-12-15

    Microbial water quality assessment currently relies on cultivation-based methods. Nucleic acid-based techniques such as quantitative PCR (qPCR) enable more rapid and specific detection of target organisms and propidium monoazide (PMA) treatment facilitates the exclusion of false positive results caused by DNA from dead cells. Established molecular assays (qPCR and PMA-qPCR) for legally defined microbial quality parameters (Escherichia coli, Enterococcus spp. and Pseudomonas aeruginosa) and indicator organism group of coliforms (implemented on the molecular detection of Enterobacteriaceae) were comparatively evaluated to conventional microbiological methods. The evaluation of an extended set of drinking and process water samples showed that PMA-qPCR for E. coli, Enterococcus spp. and P. aeruginosa resulted in higher specificity because substantial or complete reduction of false positive signals in comparison to qPCR were obtained. Complete compliance to reference method was achieved for E. coli PMA-qPCR and 100% specificity for Enterococcus spp. and P. aeruginosa in the evaluation of process water samples. A major challenge remained in sensitivity of the assays, exhibited through false negative results (7-23%), which is presumably due to insufficient sample preparation (i.e. concentration of bacteria and DNA extraction), rather than the qPCR limit of detection. For the detection of the indicator group of coliforms, the evaluation study revealed that the utilization of alternative molecular assays based on the taxonomic group of Enterobacteriaceae was not adequate. Given the careful optimization of the sensitivity, the highly specific PMA-qPCR could be a valuable tool for rapid detection of hygienic parameters such as E. coli, Enterococcus spp. and P. aeruginosa. PMID:25459225

  5. Reduction of motion blurring artifacts using respiratory gated CT in sinogram space: A quantitative evaluation

    SciTech Connect

    Lu Wei; Parikh, Parag J.; Hubenschmidt, James P.; Politte, David G.; Whiting, Bruce R.; Bradley, Jeffrey D.; Mutic, Sasa; Low, Daniel A. [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States); Department of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States); Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States)

    2005-11-15

    Techniques have been developed for reducing motion blurring artifacts by using respiratory gated computed tomography (CT) in sinogram space and quantitatively evaluating the artifact reduction. A synthetic sinogram was built from multiple scans intercepting a respiratory gating window. A gated CT image was then reconstructed using the filtered back-projection algorithm. Wedge phantoms, developed for quantifying the motion artifact reduction, were scanned while being moved using a computer-controlled linear stage. The resulting artifacts appeared between the high and low density regions as an apparent feature with a Hounsfield value that was the average of the two regions. A CT profile through these regions was fit using two error functions, each modeling the partial-volume averaging characteristics for the unmoving phantom. The motion artifact was quantified by determining the apparent distance between the two functions. The blurring artifact had a linear relationship with both the speed and the tangent of the wedge angles. When gating was employed, the blurring artifact was reduced systematically at the air-phantom interface. The gated image of phantoms moving at 20 mm/s showed similar blurring artifacts as the nongated image of phantoms moving at 10 mm/s. Nine patients were also scanned using the synchronized respiratory motion technique. Image artifacts were evaluated in the diaphragm, where high contrast interfaces intercepted the imaging plane. For patients, this respiratory gating technique reduced the blurring artifacts by 9%-41% at the lung-diaphragm interface.

  6. Quantitative evaluation of regular morning meetings aimed at improving work practices associated with effective interdisciplinary communication.

    PubMed

    Aston, Judy; Shi, Edward; Bullôt, Helen; Galway, Robyn; Crisp, Jackie

    2006-04-01

    In 2000, an interdisciplinary surgical morning meeting (SMM) was introduced into the infants' and toddlers' ward of a major paediatric hospital to help overcome a number of communication and work process problems among the health professionals providing care to children/families. The objective of this study was to evaluate the impact of the SMM on a range of work practices. Comparative design including pre- and postintervention data collection was used. Data were collected on 100 patient records. Twenty children, from each of the five diagnostic-related groups most commonly admitted to the ward, were included. Demographic, medical review, documentation, critical incidents and complaint variables were obtained from three sources: the hospital clinical information system, the children's medical records and the hospital reporting systems for complaints and critical incidents. Children in the postintervention group were significantly more likely to be reviewed regularly by medical staff, to be reviewed in the morning, to have plans for discharge documented regularly throughout their admission and to have admission summary sheets completed at the time of discharge. The findings of the quantitative evaluation add some weight to the arguments for the purposely structured introduction of interdisciplinary teams into acute-care environments. PMID:16529591

  7. Image analysis techniques. The problem of the quantitative evaluation of thechromatin ultrastructure.

    PubMed

    Maraldi, N M; Marinelli, F; Squarzoni, S; Santi, S; Barbieri, M

    1991-02-01

    The application of image analysis methods to conventional thin sections for electron microscopy to analyze the chromatin arrangement are quite limited. We developed a method which utilizes freeze-fractured samples; the results indicate that the method is suitable for identifying the changes in the chromatin arrangement which occur in physiological, experimental and pathological conditions. The modern era of image analysis begins in 1964, when pictures of the moon transmitted by Ranger 7 were processed by a computer. This processing improved the original picture by enhancing and restoring the image affected by various types of distorsion. These performances have been allowed by the third-generation of computers having the speed and the storage capabilities required for practical use of image processing algorithms. Each image can be converted into a two-dimensional light intensity function: f (x, y), where x and y are the spatial coordinates and f value is proportional to the gray level of the image at that point. The digital image is therefore a matrix whose elements are the pixels (picture elements). A typical digital image can be obtained with a quality comparable to monochrome TV, with a 512×512 pixel array with 64 gray levels. The magnetic disks of commercial minicomputers are thus capable of storing some tenths of images which can be elaborated by the image processor, converting the signal into digital form. In biological images, obtained by light microscopy, the digitation converts the chromatic differences into gray level intensities, thus allowing to define the contours of the cytoplasm, of the nucleus and of the nucleoli. The use of a quantitative staining method for the DNA, the Feulgen reaction, permits to evaluate the ratio between condensed chromatin (stained) and euchromatin (unstained). The digitized images obtained by transmission electron microscopy are rich in details at high resolution. However, the application of image analysis techniques to these images and especially to those referring to nuclei, is limited by several drawbacks: i) the thin section represents only a small fraction of the nuclear volume entirely visible in optical microscope specimens; ii) the identification of nucleosomes, of the solenoid fibres and of the higher levels of compaction of the heterochromatin is not thinsectioned specimens; iii) the differences between heterochromatin and euchromatin are based only on their grey level but do not reveal possible variations of their structural organization. Therefore, the applications of image analysis to the nuclear content does not utilzes the high resolution power of e.m. images and simply quantify the areas occupied by electron-dense chromatin with respect to the more electron-transparent ones. This result is less significative of those obtainable by optical microscopy, since the electron staining is not quantitative as the Fulgen reaction. On the other hand, the following problems still remain unresolved and should be clarified only by the use of quantitative image analysis: ultrastructural organization of the different types of heterochromatin (1); relationships between gene activation, transcription and chromatin decondensation; chromatin arrangement transformation induced by exogenous agents. In order to face these problems, in the last years we applied image analysis to cell or tissue specimens frozen in liquid nitrogen and then fractured in order to expose the inner content of the nucleus (Fig. 1). The obtained metal replicas represent very suitable specimens for digitalized image elaboration, since the fibers which give rise to the chromatin domains are exposed by the fracturing and evidentiated by the shadowing as black dots with a clear white shadow (Fig. 2). Therefore, their size and shape can be quantitatively evaluated by a digital image processor; in this vay the structural elements of the chromatin fibres are also detectable inside a fractured nucleus and their relative percentage ca be determined in each nuclear area (Fig. 3). This type of analysis has been initially u

  8. Quantitative Evaluation of the Environmental Impact Quotient (EIQ) for Comparing Herbicides

    PubMed Central

    Kniss, Andrew R.; Coburn, Carl W.

    2015-01-01

    Various indicators of pesticide environmental risk have been proposed, and one of the most widely known and used is the environmental impact quotient (EIQ). The EIQ has been criticized by others in the past, but it continues to be used regularly in the weed science literature. The EIQ is typically considered an improvement over simply comparing the amount of herbicides applied by weight. Herbicides are treated differently compared to other pesticide groups when calculating the EIQ, and therefore, it is important to understand how different risk factors affect the EIQ for herbicides. The purpose of this work was to evaluate the suitability of the EIQ as an environmental indicator for herbicides. Simulation analysis was conducted to quantify relative sensitivity of the EIQ to changes in risk factors, and actual herbicide EIQ values were used to quantify the impact of herbicide application rate on the EIQ Field Use Rating. Herbicide use rate was highly correlated with the EIQ Field Use Rating (Spearman’s rho >0.96, P-value <0.001) for two herbicide datasets. Two important risk factors for herbicides, leaching and surface runoff potential, are included in the EIQ calculation but explain less than 1% of total variation in the EIQ. Plant surface half-life was the risk factor with the greatest relative influence on herbicide EIQ, explaining 26 to 28% of the total variation in EIQ for actual and simulated EIQ values, respectively. For herbicides, the plant surface half-life risk factor is assigned values without any supporting quantitative data, and can result in EIQ estimates that are contrary to quantitative risk estimates for some herbicides. In its current form, the EIQ is a poor measure of herbicide environmental impact. PMID:26121252

  9. Experimental evaluation of spectral-based quantitative ultrasound imaging using plane wave compounding.

    PubMed

    Salles, Sebastien; Liebgott, Hervé; Basset, Olivier; Cachard, Christian; Vray, Didier; Lavarello, Roberto

    2014-11-01

    Quantitative ultrasound (QUS) based on backscatter coefficient (BSC) estimation has shown potential for tissue characterization. Beamforming using plane wave compounding has advantages for echographic, Doppler, and elastographic imaging; however, to date, plane wave compounding has not been experimentally evaluated for the purpose of BSC estimation. In this study, two BSC-derived parameters (i.e., the BSC midband fit and intercept) were estimated from experimental data obtained using compound plane wave beamforming. For comparison, QUS parameters were also estimated from data obtained using both fixed focus and dynamic receive beamforming. An ultrasound imaging system equipped with a 9-MHz center frequency, 64-element array was used to collect data up to a depth of 45 mm. Two gelatin phantoms with randomly distributed 20-?m inclusions with a homogeneous scatterer concentration and a two-region scatterer concentration were used for assessing the precision and lateral resolution of QUS imaging, respectively. The use of plane wave compounding resulted in accurate QUS estimation (i.e., bias in the BSC parameters of less than 2 dB) and relatively constant lateral resolution (i.e., BSC midband fit 10% to 90% rise distance ranging between 1.0 and 1.5 mm) throughout a 45 mm field of view. Although both fixed focus and dynamic receive beamforming provided the same performance around the focal depth, the reduction in SNR away from the focus resulted in a reduced field of view in the homogeneous phantom (i.e., only 28 mm). The lateral resolution also degraded away from the focus, with up to a 2-fold and 10-fold increase in the rise distance at 20 mm beyond the focal depth for dynamic receive and fixed focus beamforming, respectively. These results suggest that plane wave compounding has the potential to improve the performance of spectral-based quantitative ultrasound over other conventional beamforming strategies. PMID:25389161

  10. Correction for FDG PET dose extravasations: Monte Carlo validation and quantitative evaluation of patient studies

    SciTech Connect

    Silva-Rodríguez, Jesús, E-mail: jesus.silva.rodriguez@sergas.es; Aguiar, Pablo, E-mail: pablo.aguiar.fernandez@sergas.es [Fundación Ramón Domínguez, Santiago de Compostela, Galicia (Spain) [Fundación Ramón Domínguez, Santiago de Compostela, Galicia (Spain); Servicio de Medicina Nuclear, Complexo Hospitalario Universidade de Santiago de Compostela (USC), 15782, Galicia (Spain); Grupo de Imaxe Molecular, Instituto de Investigación Sanitarias (IDIS), Santiago de Compostela, 15706, Galicia (Spain); Sánchez, Manuel; Mosquera, Javier; Luna-Vega, Víctor [Servicio de Radiofísica y Protección Radiológica, Complexo Hospitalario Universidade de Santiago de Compostela (USC), 15782, Galicia (Spain)] [Servicio de Radiofísica y Protección Radiológica, Complexo Hospitalario Universidade de Santiago de Compostela (USC), 15782, Galicia (Spain); Cortés, Julia; Garrido, Miguel [Servicio de Medicina Nuclear, Complexo Hospitalario Universitario de Santiago de Compostela, 15706, Galicia, Spain and Grupo de Imaxe Molecular, Instituto de Investigación Sanitarias (IDIS), Santiago de Compostela, 15706, Galicia (Spain)] [Servicio de Medicina Nuclear, Complexo Hospitalario Universitario de Santiago de Compostela, 15706, Galicia, Spain and Grupo de Imaxe Molecular, Instituto de Investigación Sanitarias (IDIS), Santiago de Compostela, 15706, Galicia (Spain); Pombar, Miguel [Servicio de Radiofísica y Protección Radiológica, Complexo Hospitalario Universitario de Santiago de Compostela, 15706, Galicia (Spain)] [Servicio de Radiofísica y Protección Radiológica, Complexo Hospitalario Universitario de Santiago de Compostela, 15706, Galicia (Spain); Ruibal, Álvaro [Servicio de Medicina Nuclear, Complexo Hospitalario Universidade de Santiago de Compostela (USC), 15782, Galicia (Spain) [Servicio de Medicina Nuclear, Complexo Hospitalario Universidade de Santiago de Compostela (USC), 15782, Galicia (Spain); Grupo de Imaxe Molecular, Instituto de Investigación Sanitarias (IDIS), Santiago de Compostela, 15706, Galicia (Spain); Fundación Tejerina, 28003, Madrid (Spain)

    2014-05-15

    Purpose: Current procedure guidelines for whole body [18F]fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET) state that studies with visible dose extravasations should be rejected for quantification protocols. Our work is focused on the development and validation of methods for estimating extravasated doses in order to correct standard uptake value (SUV) values for this effect in clinical routine. Methods: One thousand three hundred sixty-seven consecutive whole body FDG-PET studies were visually inspected looking for extravasation cases. Two methods for estimating the extravasated dose were proposed and validated in different scenarios using Monte Carlo simulations. All visible extravasations were retrospectively evaluated using a manual ROI based method. In addition, the 50 patients with higher extravasated doses were also evaluated using a threshold-based method. Results: Simulation studies showed that the proposed methods for estimating extravasated doses allow us to compensate the impact of extravasations on SUV values with an error below 5%. The quantitative evaluation of patient studies revealed that paravenous injection is a relatively frequent effect (18%) with a small fraction of patients presenting considerable extravasations ranging from 1% to a maximum of 22% of the injected dose. A criterion based on the extravasated volume and maximum concentration was established in order to identify this fraction of patients that might be corrected for paravenous injection effect. Conclusions: The authors propose the use of a manual ROI based method for estimating the effectively administered FDG dose and then correct SUV quantification in those patients fulfilling the proposed criterion.

  11. Evaluation of infectious titer in a candidate HSV type 2 vaccine by a quantitative molecular approach

    PubMed Central

    2013-01-01

    Background One of the critical tasks in analytical testing is to monitor and assign the infectivity or potency of viral based vaccines from process development to production of final clinical lots. In this study, a high throughput RT-qPCR based approach was developed to evaluate the infectious titre in a replication-defective HSV-2 candidate vaccine, called HSV529. This assay is a combination of viral propagation and quantitative RT-PCR which measures the amount of RNA in infected cells after incubation with test samples. Results The relative infectious titre of HSV529 candidate vaccine was determined by a RT-qPCR method targeting HSV-2 gD2 gene. The data were analyzed using the parallel-line analysis as described in the European Pharmacopoeia 8th edition. The stability of HSV529 test samples were also investigated in a concordance study between RT-qPCR infectivity assay and a classical plaque assays. A suitable correlation was determined between both assays using an identical sample set in both assays. The RT-qPCR infectivity assay was further characterized by evaluating the intermediate precision and accuracy. The coefficient of variation from the six independent assays was less than 10%. The accuracy of each of the assay was also evaluated in the range of 92.91% to 120.57%. Conclusions Our data demonstrate that the developed RT-qPCR infectivity assay is a rapid high throughput approach to quantify the infectious titer or potency of live attenuated or defective viral-based vaccines, an attribute which is associated with product quality. PMID:24313978

  12. Quantitative x-ray phase nanotomography

    NASA Astrophysics Data System (ADS)

    Diaz, Ana; Trtik, Pavel; Guizar-Sicairos, Manuel; Menzel, Andreas; Thibault, Pierre; Bunk, Oliver

    2012-01-01

    X-ray ptychographic computed tomography has recently emerged as a nondestructive characterization tool for samples with representative sizes of several tens of micrometers, yet offering a resolution currently lying in but not limited to the 100-nm range. Here we evaluate the quantitativeness of this technique using a model sample with a known structure and density, and we discuss its sensitivity as a function of resolution. Additionally, we show an example application for the determination of the mass density of individual 2-?m-sized SiO2 microspheres with a relative error of 2%. The accuracy and sensitivity demonstrated in this paper will enable quantitative imaging, segmentation, and identification of different phases in complex materials at the nanoscale.

  13. Trends in nondestructive imaging of IC packages

    NASA Astrophysics Data System (ADS)

    Moore, T. M.; Hartfield, C. D.

    1998-11-01

    Since the industry-wide conversion to surface mount packages in the mid-1980's, nondestructive imaging of moisture induced delaminations and cracks in plastic packaged ICs by scanning acoustic microscopy has been a critically important capability. Subsurface imaging and phase analysis of echoes has allowed scanning acoustic microscopy to become the primary nondestructive technique for component level inspection of packaged ICs and is sensitive to defects that are undetectable by real time x-ray inspection. It has become the preferred method for evaluating moisture sensitivity, and for many package processes, provides more reliable detection of wire bond degradation than physical cross sectioning or conventional electrical testing. However, the introduction of new technologies such as ball grid array (BGA) and flip chip packages demands improvements in acoustic inspection techniques. Echoes from the laminated substrates in BGA packages produce interference problems. Phase inversion detection is an important advantage of pulse-echo imaging of molded surface mount packages. However, phase inversion is not always helpful for delamination detection in these new packages, due to the properties of the materials involved. The requirement to nondestructively inspect flip chip interconnect bumps has arisen. Alternative approaches such as through-transmission screening of BGAs and high frequency (>200 MHz) pulse-echo inspection of flip chip bumps are addressing these new issues. As the acoustic frequency approaches the limits dictated by attenuation, new methods of frequency-domain signal analysis will become important for routine inspection and may give acoustic microscopy a predictive capability.

  14. High Accuracy Optical Flow Method Based on a Theory for Warping: Implementation and Qualitative\\/Quantitative Evaluation

    Microsoft Academic Search

    Mohammad Faisal; John Barron

    2007-01-01

    We describe the implementation of a 2D optical flow al- gorithm published in the European Conference on Computer Vision (ECCV 2004) by Brox et al. (1) (best paper award) and a qualitative and quantitative evaluation of it for a number of synthetic and real im- age sequences. Their optical flow method combines three assumptions: a brightness constancy assumption, a gradient

  15. Evaluation of stable labeled compounds as internal standards for quantitative GC\\/MS determinations. Final report Jul 79Jul 81

    Microsoft Academic Search

    Colby

    1983-01-01

    The report gives results of an investigation of the use of stable isotopically labeled compounds as internal standards for quantitative isotope dilution GC\\/MS determinations. The availability of labeled compounds and the costs associated with using them for routine analyses were evaluated using the volatile, acid, and base\\/neutral fraction priority pollutants as a target component base. About 75 percent of these

  16. Quantitative evaluation of the stretch reflex before and after hydro kinesy therapy in patients affected by spastic paresis

    Microsoft Academic Search

    Paolo Pagliaro; Paola Zamparo

    1999-01-01

    The aim of this study was the quantitative evaluation of the myotatic reflex in a group of 26 patients affected by stationary spastic paresis (6: hemiparesis; 5: paraparesis; 8: tetraparesis; 7: multiple sclerosis) before and after a treatment of hydro-kinesy therapy. The treatment was carried out in an indoor pool containing warm (32°C) sea water and consisted of active and

  17. EnviLOD WP5: Quantitative Evaluation of LOD-based Semantic Enrichment on Environmental Science Literature

    E-print Network

    Maynard, Diana

    EnviLOD WP5: Quantitative Evaluation of LOD-based Semantic Enrichment on Environmental Science Literature Kalina Bontcheva1,, Niraj Aswani1, Johanna Kieniewicz2, Stephen Andrews2, Michael Wallis3 1 Department of Computer Science, University of Sheffield, Sheffield, UK 2 The British Library, London, UK 3 HR

  18. Evaluation of rapid DNA extraction methods for the quantitative detection of fungi using real-time PCR analysis

    Microsoft Academic Search

    Richard A. Haugland; Nichole Brinkman; Stephen J. Vesper

    2002-01-01

    Three comparatively rapid methods for the extraction of DNA from fungal conidia and yeast cells in environmental (air, water and dust) samples were evaluated for use in real-time PCR (TaqMan™) analyses. A simple bead milling method was developed to provide sensitive, accurate and precise quantification of target organisms in air and water (tap and surface) samples. However, quantitative analysis of

  19. Nondestructive Determination of Bond Strength

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Although many nondestructive techniques have been applied to detect disbonds in adhesive joints, no absolutely reliable nondestructive method has been developed to detect poor adhesion and evaluate the strength of bonded joints prior to the present work which used nonlinear ultrasonic methods to investigate adhesive bond cure conditions. Previously, a variety of linear and nonlinear ultrasonic methods with water coupling had been used to study aluminum-adhesive-aluminum laminates, prepared under different adhesive curing conditions, for possible bond strength determination. Therefore, in the course of this research effort, a variety of finite-amplitude experimental methods which could possibly differentiate various cure conditions were investigated, including normal and oblique incidence approaches based on nonlinear harmonic generation as well as several non-collinear two-wave interaction approaches. Test samples were mechanically scanned in various ways with respect to the focus of a transmitting transducer operated at several variable excitation frequencies and excitation levels. Even when powerful sample-related resonances were exploited by means of a frequency scanning approach, it was very difficult to isolate the nonlinear characteristics of adhesive bonds. However, a multi-frequency multi-power approach was quite successful and reliable. Ultrasonic tone burst signals at increasing power levels, over a wide frequency range, were transmitted through each bond specimen to determine its excitation dependent nonlinear harmonic resonance behavior. Relative amplitude changes were observed particularly in the higher harmonic spectral data and analyzed using a local displacement and strain analysis in the linear approximation. Two analysis approaches of the excitation-dependent data at specific resonances were found to be quite promising. One of these approaches may represent a very robust algorithm for classifying an adhesive bond as being properly cured or not. Another approach, in addition to differentiation between various cure conditions, may even provide information with respect to the bond strength. Several technical papers were published during the course of this research and a summary is presented in the Ph.D. dissertation of Tobias P. Berndt, a graduate student financially supported by this NASA Grant.

  20. An Evaluation of Quantitative Methods of Determining the Degree of Melting Experienced by a Chondrule

    NASA Technical Reports Server (NTRS)

    Nettles, J. W.; Lofgren, G. E.; Carlson, W. D.; McSween, H. Y., Jr.

    2004-01-01

    Many workers have considered the degree to which partial melting occurred in chondrules they have studied, and this has led to attempts to find reliable methods of determining the degree of melting. At least two quantitative methods have been used in the literature: a convolution index (CVI), which is a ratio of the perimeter of the chondrule as seen in thin section divided by the perimeter of a circle with the same area as the chondrule, and nominal grain size (NGS), which is the inverse square root of the number density of olivines and pyroxenes in a chondrule (again, as seen in thin section). We have evaluated both nominal grain size and convolution index as melting indicators. Nominal grain size was measured on the results of a set of dynamic crystallization experiments previously described, where aliquots of LEW97008(L3.4) were heated to peak temperatures of 1250, 1350, 1370, and 1450 C, representing varying degrees of partial melting of the starting material. Nominal grain size numbers should correlate with peak temperature (and therefore degree of partial melting) if it is a good melting indicator. The convolution index is not directly testable with these experiments because the experiments do not actually create chondrules (and therefore they have no outline on which to measure a CVI). Thus we had no means to directly test how well the CVI predicted different degrees of melting. Therefore, we discuss the use of the CVI measurement and support the discussion with X-ray Computed Tomography (CT) data.

  1. Quantitative evaluation of radiation-induced changes in sperm morphology and chromatin distribution

    SciTech Connect

    Aubele, M.; Juetting, U.R.; Rodenacker, K.; Gais, P.; Burger, G.; Hacker-Klom, U. (Institut fuer Strahlenschutz, Neuherberg (Germany, F.R.))

    1990-01-01

    Sperm head cytometry provides a useful assay for the detection of radiation-induced damage in mouse germ cells. Exposure of the gonads to radiation is known to lead to an increase of diploid and higher polyploid sperm and of sperm with head shape abnormalities. In the pilot studies reported here quantitative analysis of the total DNA content, the morphology, and the chromatin distribution of mouse sperm was performed. The goal was to evaluate the discriminative power of features derived by high resolution image cytometry in distinguishing sperm of control and irradiated mice. Our results suggest that besides the induction of the above mentioned variations in DNA content and shape of sperm head, changes of the nonhomogeneous chromatin distribution within the sperm may also be used to quantify the radiation effect on sperm cells. Whereas the chromatin distribution features show larger variations for sperm 21 days after exposure (dpr), the shape parameters seem to be more important to discriminate sperm 35 dpr. This may be explained by differentiation processes, which take place in different stages during mouse spermatogenesis.

  2. Evaluation of the Abbott Real-Time HIV-1 quantitative assay with dried blood spot specimens.

    PubMed

    Marconi, A; Balestrieri, M; Comastri, G; Pulvirenti, F R; Gennari, W; Tagliazucchi, S; Pecorari, M; Borghi, V; Marri, D; Zazzi, M

    2009-01-01

    The Abbott Real-Time HIV-1 assay was evaluated for its performance in quantification of human immunodeficiency virus type 1 (HIV-1) RNA in dried blood spot (DBS) samples. In total, 169 blood samples with detectable plasma HIV-1 RNA were used to extract RNA from paired DBS and liquid plasma samples, using the automated Abbott m Sample Preparation System (m2000sp). HIV-1 RNA was then quantitated by the m2000rt RealTime analyser. RNA samples suitable for real-time PCR were obtained from all but one (99.4%) of the DBS samples and HIV-1 RNA was detected in 163/168 (97.0%) samples. The correlation between HIV-1 RNA values measured in paired DBS and plasma samples was very high (r = 0.882), with 78.5% and 99.4% of cases differing by <0.5 and 1.0 log, respectively. Retesting of DBS replicates following 6 months of storage at 2-8 degrees C showed no loss of HIV-1 RNA in a subset of 89 samples. The feasibility of DBS testing coupled with automated sample processing, and the use of a latest-generation FDA-approved real-time PCR-based system, represents an encouraging first step for viral load measurement in reference centres in developing countries where access to antiretroviral therapy is expanding. PMID:19220340

  3. The Evaluation and Quantitation of Dihydrogen Metabolism Using Deuterium Isotope in Rats

    PubMed Central

    Hyspler, Radomir; Ticha, Alena; Schierbeek, Henk; Galkin, Alexander; Zadak, Zdenek

    2015-01-01

    Purpose Despite the significant interest in molecular hydrogen as an antioxidant in the last eight years, its quantitative metabolic parameters in vivo are still lacking, as is an appropriate method for determination of hydrogen effectivity in the mammalian organism under various conditions. Basic Procedures Intraperitoneally-applied deuterium gas was used as a metabolic tracer and deuterium enrichment was determined in the body water pool. Also, in vitro experiments were performed using bovine heart submitochondrial particles to evaluate superoxide formation in Complex I of the respiratory chain. Main Findings A significant oxidation of about 10% of the applied dose was found under physiological conditions in rats, proving its antioxidant properties. Hypoxia or endotoxin application did not exert any effect, whilst pure oxygen inhalation reduced deuterium oxidation. During in vitro experiments, a significant reduction of superoxide formation by Complex I of the respiratory chain was found under the influence of hydrogen. The possible molecular mechanisms of the beneficial effects of hydrogen are discussed, with an emphasis on the role of iron sulphur clusters in reactive oxygen species generation and on iron species-dihydrogen interaction. Principal Conclusions According to our findings, hydrogen may be an efficient, non-toxic, highly bioavailable and low-cost antioxidant supplement for patients with pathological conditions involving ROS-induced oxidative stress. PMID:26103048

  4. Quantitative evaluation of the Myotatic Reflex in Hemiplegic and Paraplegic patients.

    PubMed

    Zamparo; Capelli; Pagliaro; De Luca G; Pertoldi; Saccavini; Di Prampero PE

    1997-01-01

    The aim of this study was the quantitative evaluation of the myotatic reflex in a group of 11 subjects affected by spastic paresis of the lower limbs (8 hemiplegic and 3 paraplegic patients) and, for comparison, in a group of 7 healthy subjects. The parameters taken into account were the gain of the reflex and the time delay between the input and the mechanical output. The gain was calculated as the ratio between: i) the peak value of the input force (FPH) measured by means of an instrumented hammer with which the patellar tendon was hit; and ii) the peak value of the corresponding reflex force of the quadriceps femoris (FPQ) measured by means of a load cell connected to the subject's ankle. The gain of the reflex (FPQ/FPH) was found to be 1.9 to 2.4 times larger in patients as compared to control subjects and, among the patients to be twice at low, as compared to high, levels of stimulation. Among the hemiplegic patients, significant differences were found in the time delay of the response between the affected and unaffected limbs. Since both the intensity of the reflex and its gain were found to depend on the mechanical energy input, both parameters must be taken in to account if a diagnosis of spasticity has to be made. PMID:10352468

  5. STIM evaluation in GeoPIXE to complement the quantitative dynamic analysis

    NASA Astrophysics Data System (ADS)

    Pallon, J.; Ryan, C. G.; Arteaga Marrero, N.; Elfman, M.; Kristiansson, P.; Nilsson, E. J. C.; Nilsson, C.

    2009-06-01

    The GeoPIXE software for quantitative PIXE trace element imaging and analysis is a well established package for evaluation of characteristic X-ray data for both PIXE and SXRF. For the case of microbeam applications on semi-thick samples knowledge of the local areal density distribution is important for precise quantification. A technique is reported to achieve this using the measurement of beam particle energy loss as it traverses the sample, as in scanning transmission ion microscopy (STIM). New functionality is added to the GeoPIXE code through integration of routines for STIM sorting of event-by-event data to create elemental maps of the mean energy after traversing the sample. Integration of stopping powers for a given sample matrix then permits the measured energy loss to be related to the local areal density. In a further step, this information is used for X-ray absorption corrections made directly to the PIXE analysis results. As a complement, user-written plugins operating on single STIM spectra have been used to compare the estimated areal density from chosen spots with the corresponding values calculated with the new GeoPIXE routines. The additions made to the code allow a more precise quantification to be done on inhomogeneous, semi-thick samples.

  6. In vivo quantitative evaluation of gold nanocages' kinetics in sentinel lymph nodes by photoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Cai, Xin; Li, Weiyang; Kim, Chulhong; Yuan, Yuchen; Xia, Younan; Wang, Lihong V.

    2012-02-01

    As a new class of sentinel lymph node (SLN) tracers for photoacoustic (PA) imaging, Au nanocages offer the advantages of noninvasiveness, strong optical absorption in the near-infrared region (for deep penetration), and accumulation in higher concentrations than the initial injected solution. By monitoring the amplitude changes of PA signals in an animal model, we quantified the accumulations of nanocages in SLNs over time. Based on this method, we quantitatively evaluated the kinetics of gold nanocages in SLN in terms of concentration, size, and surface modification. We could detect the SLN at an Au nanocage injection concentration of 50 pM and a dose of 100 ?L in vivo. This concentration is about 40 times less than the previously reported value. We also investigated the influence of nanocages' size (50 nm and 30 nm in edge length), and the effects of surface modification (with positive, or neutral, or negative surface charges). The results are helpful to develop this AuNC-based PA imaging system for noninvasive lymph node mapping, providing valuable information about metastatic cancer staging.

  7. Qualitative and quantitative evaluation of a pilot integrative coping and resiliency program for healthcare professionals.

    PubMed

    Tarantino, Bonnie; Earley, Michael; Audia, Donna; D'Adamo, Christopher; Berman, Brian

    2013-01-01

    Stress, fatigue, and burnout are common maladies among healthcare employees. To address this problem, a holistic integrative self-care program for healthcare practitioners was designed, implemented, and evaluated. A total of 84 participants, recruited via presentations, flyers, and word of mouth, completed the 8-week program. The experiential course, entitled Healing Pathways, combined training in Reiki, guided imagery, yoga, toning, meditation, intuitive scanning, creative expression, and mentorship to foster more empowered and resilient individuals. We measured the effectiveness of the program via mixed methods consisting of qualitative interviews providing in-depth feedback and quantitative analysis demonstrating statistically significant benefit. Participants reported significantly lower levels of stress and significantly increased confidence in their ability to cope at treatment conclusion (8 weeks) and long-term follow-up (12 months). These findings suggest that an integrative wellness and resiliency program, coupled with individual mentorship, may improve coping, decrease stress, and improve functioning and well-being for nurses and other health care providers. PMID:23294820

  8. Quantitative evaluation of minerals in lignites and intraseam sediments from the Achlada Basin, Northern Greece

    SciTech Connect

    Nikolaos Koukouzas; Colin R. Ward; Dimitra Papanikolaou; Zhongsheng Li [Institute for Solid Fuels Technology and Applications, Athens (Greece). Centre for Research and Technology Hellas

    2009-04-15

    Seven core samples (five lignite samples and two intraseam nonlignite rock samples) from the Achlada open-cut mine in northern Greece were characterized by X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. Quantitative evaluation of the mineral phases in each sample was made from the powder X-ray diffractograms using Siroquant commercial interpretation software, which is based on Rietveld principles. The main minerals in the low-temperature ash (LTA) ash of the lignites are kaolinite and illite, with bassanite and quartz in minor proportions. The nonlignite rock samples mainly consist of illite, mica (2M1), and kaolinite (poorly ordered), along with quartz, chlorite (ferroan), feldspar (albite), rutile, and dolomite. Oriented-aggregate XRD study further shows the presence of smectite, and interstratified illite/smectite (I/S), in the clay fractions of the lignite and rock samples, with the mineral matter of the lignites being richer in kaolinite, smectite, and I/S than in mineral matter of the nonlignite materials. The differences in mineralogy between the lignite and the rock materials probably reflect selective concentration of minerals in the original peat during deposition, combined with authigenic precipitation of minerals such as kaolinite in the peat deposit. Inferred chemical analyses derived from the XRD data show reasonably good correlations with chemical data obtained by direct ash analysis, especially if the smectite and I/S are taken into account. This provides a link between mineralogical and chemical studies that may be valuable in evaluating the behavior of the lignite under different utilization conditions. 27 refs., 4 figs., 6 tabs.

  9. A quantitative evaluation of brain dysfunction and body-burden of toxic metals

    PubMed Central

    Geier, David A.; Pretorius, Harold T.; Richards, Nichole M.; Geier, Mark R.

    2012-01-01

    Summary Background Toxic metal exposure (e.g. Hg, Pb, As) exposure is known to induce significant adverse effects on human brain function. The aim this study was to assess toxic metal body-burden in relation to potential brain dysfunction in patients diagnosed with neurological disorders (NDs). Material/Methods The Liberty Institutional Review Board (Deland, FL) approved the present study. Quantitative, fractionated, random urinary porphyrin testing (?g/L) from the Clinical Laboratory Improvement Act/Amendment (CLIA)-approved Laboratory Corporation of America (LabCorp) and cortical perfusion index (CPi) values from single-photon-emission-computed-tomography (SPECT) brain scans were employed to evaluate a prospective cohort of qualifying patients with diagnosed NDs (n=52) presenting for medical care at an endocrinology practice in the Cincinnati, OH area. Results Patients with more severe in comparison to mild brain dysfunction had significant increases in the mean urinary concentration of uroporphyrins (uP), coproporphyrins I (cP I), and total cP (cP I + III), as well as a trend towards significantly increased mean urinary concentration of pentacarboxyporphyins (5cxP) and cP III. A significant positive correlation between Hg body-burden associated porphyrins (5cxP + cP I + cP III) and increased brain dysfunction was observed. Conclusions The present study associated brain dysfunction with Hg body-burden in a cohort of patients diagnosed with NDs, but the contributions of other heavy metals or genetic factors cannot be ruled-out. Additional studies should be conducted to evaluate the consistency of the present findings with examinations of other populations. PMID:22739732

  10. Quantitative evaluation of environmental impact assessment, based on aquatic monitoring programs at three nuclear power plants

    Microsoft Academic Search

    K. L. Gore; J. M. Thomas; D. G. Watson

    1979-01-01

    Aquatic monitoring programs conducted at three nuclear power plants were quantitatively reviewed. Explanation of type of data sets available and types of statistical analyses performed are provided. Suggestions are offered on how future efforts could be reallocated to provide a more quantitative approach to aquatic impact assessment.

  11. A quantitative framework to evaluate incidental take and endangered species population viability

    Microsoft Academic Search

    Conor P. McGowan; Mark R. Ryan

    2009-01-01

    Incidental take is the permitted unintended or collateral killing, harassment, or habitat destruction of a protected species under endangered species law and is permissible as long as the take does not jeopardize the species’ persistence in the wild. However, take is seldom addressed in a quantitative or population modeling context and the criterion of “jeopardy” has no universal, quantitative definition.

  12. Nondestructive characterization of the elastic constants of fiber reinforced composites

    NASA Technical Reports Server (NTRS)

    Mal, Ajit K.; Lih, Shyh-Shiuh; Bar-Cohen, Yoseph

    1993-01-01

    Composite structural components may be subjected to a variety of defects resulting in a sharp reduction in their load carrying capacity or even catastrophic failure. Thus, it is extremely important to have the means to monitor the degradation suffered by critical components of a structure for safe operation during its service life. A nondestructive method based on ultrasonics has recently been developed for the quantitative evaluation of composite structural components during service. The experimental part of the technique uses a two-transducer, pitch-catch type arrangement to generate a variety of elastic waves within the specimen immersed in water. The recorded reflection data are then analyzed by means of a theoretical model to back out the relevant properties. In this paper the method is applied to determine the stiffness constants of unidirectional graphite/epoxy materials. The measurements are shown to be efficient and sufficiently accurate so that it can be used for early detection of material degradation in composite structural elements during service.

  13. Quantitative evaluation of ozone and selected climate parameters in a set of EMAC simulations

    NASA Astrophysics Data System (ADS)

    Righi, M.; Eyring, V.; Gottschaldt, K.-D.; Klinger, C.; Frank, F.; Jöckel, P.; Cionni, I.

    2014-10-01

    Four simulations with the ECHAM/MESSy Atmospheric Chemistry (EMAC) model have been evaluated with the Earth System Model Validation Tool (ESMValTool) to identify differences in simulated ozone and selected climate parameters that resulted from (i) different setups of the EMAC model (nudged vs. free-running) and (ii) different boundary conditions (emissions, sea surface temperatures (SSTs) and sea-ice concentrations (SICs)). To assess the relative performance of the simulations, quantitative performance metrics are calculated consistently for the climate parameters and ozone. This is important for the interpretation of the evaluation results since biases in climate can impact on biases in chemistry and vice versa. The observational datasets used for the evaluation include ozonesonde and aircraft data, meteorological reanalyses and satellite measurements. The results from a previous EMAC evaluation of a model simulation with weak nudging towards realistic meteorology in the troposphere have been compared to new simulations with different model setups and updated emission datasets in free-running timeslice and nudged Quasi Chemistry-Transport Model (QCTM) mode. The latter two configurations are particularly important for chemistry-climate projections and for the quantification of individual sources (e.g. transport sector) that lead to small chemical perturbations of the climate system, respectively. With the exception of some specific features which are detailed in this study, no large differences that could be related to the different setups of the EMAC simulations (nudged vs. free-running) were found, which offers the possibility to evaluate and improve the overall model with the help of shorter nudged simulations. The main differences between the two setups is a better representation of the tropospheric and stratospheric temperature in the nudged simulations, which also better reproduce stratospheric water vapour concentrations, due to the improved simulation of the temperature in the tropical tropopause layer. Ozone and ozone precursor concentrations on the other hand are very similar in the different model setups, if similar boundary conditions are used. Different boundary conditions however lead to relevant differences in the four simulations. SSTs and SICs, which are prescribed in all simulations, play a key role in the representation of the ozone hole, which is significantly underestimated in some experiments. A bias that is present in all simulations is an overestimation of tropospheric column ozone, which is significantly reduced when lower lightning emissions of nitrogen oxides are used. To further investigate possible other reasons for such bias, two sensitivity simulations with an updated scavenging routine and the addition of a newly proposed HNO3-forming channel of the HO2+ NO reaction were performed. The update in the scavenging routine resulted in a slightly better representation of ozone compared to the reference simulation. The introduction of the new HNO3-forming channel significantly reduces this bias. Therefore, including the new reaction rate could potentially be important for a realistic simulation of tropospheric ozone, although laboratory experiments and other models studies need to confirm this hypothesis and some modifications to the rate, which has a strong dependence on water vapour, might also still be needed.

  14. Nondestructive Acoustic Imaging Techniques

    NASA Astrophysics Data System (ADS)

    Schmitz, Volker

    Acoustic imaging techniques are used in the field of nondestructive testing of technical components to measure defects such as lack of side wall fusion or cracks in welded joints. Data acquisition is performed by a remote-controlled manipulator and a PC for the mass storage of the high-frequency time-of-flight data at each probe position. The quality of the acoustic images and the interpretation relies on the proper understanding of the transmitted wave fronts and the arrangement of the probes in pulse-echo mode or in pitch-and-catch arrangement. The use of the Synthetic Aperture Focusing Technique allows the depth-dependent resolution to be replaced by a depth-independent resolution and the signal-to-noise ratio to be improved. Examples with surface-connected cracks are shown to demonstrate the improved features. The localization accuracy could be improved by entering 2-dimensional or 3-dimensional reconstructed data into the environment of a 3-dimensional CAD drawing. The propagation of ultrasonic waves through austenitic welds is disturbed by the anisotropic and inhomogeneous structure of the material. The effect is more or less severe depending upon the longitudinal or shear wave modes. To optimize the performance of an inspection software tool, a 3-dimensional CAD-Ray program has been implemented, where the shape of the inhomogeneous part of a weld can be simulated together with the grain structure based on the elastic constants. Ray-tracing results are depicted for embedded and for surface-connected defects.

  15. Development and Evaluation of a Quantitative PCR Assay Targeting Sandhill Crane (Grus canadensis) Fecal Pollution

    PubMed Central

    Ryu, Hodon; Lu, Jingrang; Vogel, Jason; Elk, Michael; Chávez-Ramírez, Felipe; Ashbolt, Nicholas

    2012-01-01

    While the microbial water quality in the Platte River is seasonally impacted by excreta from migrating cranes, there are no methods available to study crane fecal contamination. Here we characterized microbial populations in crane feces using phylogenetic analysis of 16S rRNA gene fecal clone libraries. Using these sequences, a novel crane quantitative PCR (Crane1) assay was developed, and its applicability as a microbial source tracking (MST) assay was evaluated by determining its host specificity and detection ability in environmental waters. Bacteria from crane excreta were dominated by bacilli and proteobacteria, with a notable paucity of sequences homologous to Bacteroidetes and Clostridia. The Crane1 marker targeted a dominant clade of unclassified Lactobacillales sequences closely related to Catellicoccus marimammalium. The host distribution of the Crane1 marker was relatively high, being positive for 69% (66/96) of the crane excreta samples tested. The assay also showed high host specificity, with 95% of the nontarget fecal samples (i.e., n = 553; 20 different free-range hosts) being negative. Of the presumed crane-impacted water samples (n = 16), 88% were positive for the Crane1 assay, whereas none of the water samples not impacted by cranes were positive (n = 165). Bayesian statistical models of the Crane1 MST marker demonstrated high confidence in detecting true-positive signals and a low probability of false-negative signals from environmental water samples. Altogether, these data suggest that the newly developed marker could be used in environmental monitoring studies to study crane fecal pollution dynamics. PMID:22492437

  16. Quantitative evaluation of geodiversity: development of methodological procedures with application to territorial management

    NASA Astrophysics Data System (ADS)

    Forte, J.; Brilha, J.; Pereira, D.; Nolasco, M.

    2012-04-01

    Although geodiversity is considered the setting for biodiversity, there is still a huge gap in the social recognition of these two concepts. The concept of geodiversity, less developed, is now making its own way as a robust and fundamental idea concerning the abiotic component of nature. From a conservationist point of view, the lack of a broader knowledge concerning the type and spatial variation of geodiversity, as well as its relationship with biodiversity, makes the protection and management of natural or semi-natural areas incomplete. There is a growing need to understand the patterns of geodiversity in different landscapes and to translate this knowledge for territorial management in a practical and effective point of view. This kind of management can also represent an important tool for the development of sustainable tourism, particularly geotourism, which can bring benefits not only for the environment, but also for social and economic purposes. The quantification of geodiversity is an important step in all this process but still few researchers are investing in the development of a proper methodology. The assessment methodologies that were published so far are mainly focused on the evaluation of geomorphological elements, sometimes complemented with information about lithology, soils, hidrology, morphometric variables, climatic surfaces and geosites. This results in very dissimilar areas at very different spatial scales, showing the complexity of the task and the need of further research. This current work aims the development of an effective methodology for the assessment of the maximum elements of geodiversity possible (rocks, minerals, fossils, landforms, soils), based on GIS routines. The main determinant factor for the quantitative assessment is scale, but other factors are also very important, such as the existence of suitable spatial data with sufficient degree of detail. It is expected to attain the proper procedures in order to assess geodiversity at different scales and to produce maps with the spatial representation of the geodiversity index, which could be an inestimable contribute for land-use management.

  17. Development and evaluation of a quantitative PCR assay targeting sandhill crane (Grus canadensis) fecal pollution.

    PubMed

    Ryu, Hodon; Lu, Jingrang; Vogel, Jason; Elk, Michael; Chávez-Ramírez, Felipe; Ashbolt, Nicholas; Santo Domingo, Jorge

    2012-06-01

    While the microbial water quality in the Platte River is seasonally impacted by excreta from migrating cranes, there are no methods available to study crane fecal contamination. Here we characterized microbial populations in crane feces using phylogenetic analysis of 16S rRNA gene fecal clone libraries. Using these sequences, a novel crane quantitative PCR (Crane1) assay was developed, and its applicability as a microbial source tracking (MST) assay was evaluated by determining its host specificity and detection ability in environmental waters. Bacteria from crane excreta were dominated by bacilli and proteobacteria, with a notable paucity of sequences homologous to Bacteroidetes and Clostridia. The Crane1 marker targeted a dominant clade of unclassified Lactobacillales sequences closely related to Catellicoccus marimammalium. The host distribution of the Crane1 marker was relatively high, being positive for 69% (66/96) of the crane excreta samples tested. The assay also showed high host specificity, with 95% of the nontarget fecal samples (i.e., n = 553; 20 different free-range hosts) being negative. Of the presumed crane-impacted water samples (n = 16), 88% were positive for the Crane1 assay, whereas none of the water samples not impacted by cranes were positive (n = 165). Bayesian statistical models of the Crane1 MST marker demonstrated high confidence in detecting true-positive signals and a low probability of false-negative signals from environmental water samples. Altogether, these data suggest that the newly developed marker could be used in environmental monitoring studies to study crane fecal pollution dynamics. PMID:22492437

  18. QUANTITATIVE EVALUATION OF AIR FILTRATION SYSTEMS IN USE AT ASBESTOS ABATEMENT SITES: RESEARCH IN PROGRESS

    EPA Science Inventory

    High Efficiency Particulate Air (HEPA) filtration systems serve as the principal engineering control to remove asbestos particulate from airstreams at abatement projects. owever, little quantitative information is available on the integrity of these air filtration systems in prev...

  19. Evaluation of a modified quadruple energy window scatter subtraction algorithm for quantitative imaging with In-111 

    E-print Network

    Sadler,John J.

    2000-01-01

    Accurate quantitative imaging for radionuclide uptake in tumors and organs is an important challenge in radioimmunotherapy. Inaccurate determination of uptake could adversely impact the subsequent therapy dose. An overestimation of activity could...

  20. A Fiber-Optic-Based Imaging System for Nondestructive Assessment of Cell-Seeded Tissue-Engineered Scaffolds

    PubMed Central

    Hofmann, Matthias C.; Whited, Bryce M.; Criswell, Tracy; Rylander, Marissa Nichole; Rylander, Christopher G.; Soker, Shay; Wang, Ge

    2012-01-01

    A major limitation in tissue engineering is the lack of nondestructive methods that assess the development of tissue scaffolds undergoing preconditioning in bioreactors. Due to significant optical scattering in most scaffolding materials, current microscope-based imaging methods cannot “see” through thick and optically opaque tissue constructs. To address this deficiency, we developed a fiber-optic-based imaging method that is capable of nondestructive imaging of fluorescently labeled cells through a thick and optically opaque scaffold, contained in a bioreactor. This imaging modality is based on the local excitation of fluorescent cells, the acquisition of fluorescence through the scaffold, and fluorescence mapping based on the position of the excitation light. To evaluate the capability and accuracy of the imaging system, human endothelial cells (ECs), stably expressing green fluorescent protein (GFP), were imaged through a fibrous scaffold. Without sacrificing the scaffolds, we nondestructively visualized the distribution of GFP-labeled cells through a ?500??m thick scaffold with cell-level resolution and distinct localization. These results were similar to control images obtained using an optical microscope with direct line-of-sight access. Through a detailed quantitative analysis, we demonstrated that this method achieved a resolution on the order of 20–30??m, with 10% or less deviation from standard optical microscopy. Furthermore, we demonstrated that the penetration depth of the imaging method exceeded that of confocal laser scanning microscopy by more than a factor of 2. Our imaging method also possesses a working distance (up to 8?cm) much longer than that of a standard confocal microscopy system, which can significantly facilitate bioreactor integration. This method will enable the nondestructive monitoring of ECs seeded on the lumen of a tissue-engineered vascular graft during preconditioning in vitro, as well as for other tissue-engineered constructs in the future. PMID:22439610

  1. Nondestructive techniques for characterizing mechanical properties of structural materials: An overview

    NASA Technical Reports Server (NTRS)

    Vary, A.; Klima, S. J.

    1985-01-01

    An overview of nondestructive evaluation (NDE) is presented to indicate the availability and application potentials of techniques for quantitative characterization of the mechanical properties of structural materials. The purpose is to review NDE techniques that go beyond the usual emphasis on flaw detection and characterization. Discussed are current and emerging NDE techniques that can verify and monitor entrinsic properties (e.g., tensile, shear, and yield strengths; fracture toughness, hardness, ductility; elastic moduli) and underlying microstructural and morphological factors. Most of the techniques described are, at present, neither widely applied nor widely accepted in commerce and industry because they are still emerging from the laboratory. The limitations of the techniques may be overcome by advances in applications research and instrumentation technology and perhaps by accommodations for their use in the design of structural parts.

  2. Nondestructive Characterization of Aged Components

    SciTech Connect

    Panetta, Paul D.; Toloczko, Mychailo B.; Garner, Francis A.; Balachov, Iouri I.

    2003-10-21

    It is known that high energy radiation can have numerous effects on materials. In metals and alloys, the effects include, but may not be limited to, mechanical property changes, physical property changes, compositional changes, phase changes, and dimensional changes. Metals and alloys which undergo high energy self-irradiation are also susceptible to these changes. One of the greatest concerns with irradiation of materials is the phenomenon of void swelling which has been observed in a wide variety of metals and alloys. Irradiation causes the formation of a high concentration point defects and microclusters of vacancies and interstitials. With the assistance of an inert atom such as helium, the vacancy-type defects can coalesce to form a stable bubble. This bubble will continue to grow through the net absorption of more vacancy-type defects and helium atoms, and upon reaching a certain critical size, the bubble will begin to grow at an accelerated rate without the assistance of inert atom absorption. The bubble is then said to be an unstably growing void. Depending on the alloy system and environment, swelling values can reach in excess of 50% !V/Vo where Vo is the initial volume of the material. Along with dimensional changes resulting from the formation of bubbles and voids comes changes in the macroscopically observed speed of sound, moduli, electrical resistivity, yield strength, and other properties. These effects can be detrimental to the designed operation of the aged components. In situations where irradiation has sufficient time to cause degradation to materials used in critical applications such as nuclear reactor core structural materials, it is advisable to regularly survey the material properties. It is common practice to use surveillance specimens, but this is not always possible. When surveillance materials are not available, other means for surveying the material properties must be utilized. Sometimes it is possible to core out a small sample which may be used for material properties measurements. A more appealing solution is to use nondestructive evaluation (NDE) methods.

  3. Evaluation of a Semi-Quantitative CO 2 Monitor with Pulse Oximetry for Prehospital Endotracheal Tube Placement and Management

    Microsoft Academic Search

    Andrew Macnab; Columbia V; Shawn George

    2002-01-01

    Objective: To evaluate three prototype versions of semi-quantitative end- tidal CO 2 monitors with different alarm features during prehospital or inter- facility use. Methods: Subjects were 43 adult, non-pregnant patients requiring intuba- tion, or who already were intubated and required transport. Teams at one AirEvac and seven Advanced Life Support (ALS) paramedic stations were trained in the use of the

  4. Quantitative evaluation of hydrogen sulfide at 0.3 M and 1.0 M-hydrogen-ion concentration

    E-print Network

    Machel, Albert R.

    1958-01-01

    . A Quantitative Evaluation of the Results Obtained Based on Per Cent Recovery and Solubility Product Calculations CONCLUSIONS. SUMMARY. . . BIBLIOGRAPHY APPENDIX . . 46 54 57 58 61 v O??L kY LGEOF? Page I. Data Pertaining to the Per Gent.... The groups designated by von Liebig were: A. Sulfides insoluble in dilute acids. B. Sulfides soluble in dilute acids but insoluble in the presence of alkalies. C. Sulfides not precipitated by hydrogen sulfide. The metallic ions forming sulfides...

  5. 49 CFR 193.2321 - Nondestructive tests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS Construction § 193.2321 Nondestructive tests. (a) The butt welds in metal shells of storage tanks with internal design pressure above 15 psig must be nondestructively examined in...

  6. 49 CFR 193.2321 - Nondestructive tests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS Construction § 193.2321 Nondestructive tests. (a) The butt welds in metal shells of storage tanks with internal design pressure above 15 psig must be nondestructively examined in...

  7. 49 CFR 193.2321 - Nondestructive tests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS Construction § 193.2321 Nondestructive tests. (a) The butt welds in metal shells of storage tanks with internal design pressure above 15 psig must be nondestructively examined in...

  8. 49 CFR 192.243 - Nondestructive testing.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... (d) When nondestructive testing is required under § 192.241(b), the following percentages of each day's field butt welds, selected at random by the operator, must be nondestructively tested over their entire circumference: (1) In...

  9. 49 CFR 192.243 - Nondestructive testing.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... (d) When nondestructive testing is required under § 192.241(b), the following percentages of each day's field butt welds, selected at random by the operator, must be nondestructively tested over their entire circumference: (1) In...

  10. 49 CFR 192.243 - Nondestructive testing.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... (d) When nondestructive testing is required under § 192.241(b), the following percentages of each day's field butt welds, selected at random by the operator, must be nondestructively tested over their entire circumference: (1) In...

  11. 49 CFR 193.2321 - Nondestructive tests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS Construction § 193.2321 Nondestructive tests. (a) The butt welds in metal shells of storage tanks with internal design pressure above 15 psig must be nondestructively examined in...

  12. 49 CFR 193.2321 - Nondestructive tests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS Construction § 193.2321 Nondestructive tests. (a) The butt welds in metal shells of storage tanks with internal design pressure above 15 psig must be nondestructively examined in...

  13. Federal Aviation Administration aging aircraft nondestructive inspection research plan

    NASA Technical Reports Server (NTRS)

    Seher, Chris C.

    1992-01-01

    This paper highlights the accomplishments and plans of the Federal Aviation Administration (FAA) for the development of improved nondestructive evaluation (NDE) equipment, procedures, and training. The role of NDE in aircraft safety and the need for improvement are discussed. The FAA program participants, and coordination of activities within the program and with relevant organizations outside the program are also described.

  14. Nondestructive Crack Detection in a Fuel System Component

    NASA Technical Reports Server (NTRS)

    Koshti, Ajay; Ruffino, Norman; Wincheski, Russell; Prosser, William; Winfree, William; Russell, Richard; Bryson, Craig; Devries, Robert; Engel, James; Landy, James

    2010-01-01

    The presentation examines the background and objective of nondestructive crack detection, flow control valve assembly and poppet post flight evaluation, poppet properties. magnetic property characterization of lab data, NDE, eddy current inspection, simulation, eddy current criteria, poppet cycle testing and NDE criteria, and the use of ultrasonic surface wave for crack detection.

  15. Nondestructive Characterization of Bifurcated Crack by Potential Drop Technique

    Microsoft Academic Search

    M. Saka; D. Yuasa; H. Abe

    1992-01-01

    A method was presented for the nondestructive evaluation of a crack bifurcated from a horizontal crack in a rail. The method was based on the measurement of the difference and distribution of d.c electrical potential on the top surface of thc rail.First, a problem of current flow in a plate, which contained horizontal and bifurcated cracks and was subjected to

  16. Standardizing Evaluation of pQCT Image Quality in the Presence of Subject Movement: Qualitative vs. Quantitative Assessment

    PubMed Central

    Blew, Robert M.; Lee, Vinson R.; Farr, Joshua N.; Schiferl, Daniel J.; Going, Scott B.

    2013-01-01

    Purpose Peripheral quantitative computed tomography (pQCT) is an essential tool for assessing bone parameters of the limbs, but subject movement and its impact on image quality remains a challenge to manage. The current approach to determine image viability is by visual inspection, but pQCT lacks a quantitative evaluation. Therefore, the aims of this study were to (1) examine the reliability of a qualitative visual inspection scale, and (2) establish a quantitative motion assessment methodology. Methods Scans were performed on 506 healthy girls (9–13yr) at diaphyseal regions of the femur and tibia. Scans were rated for movement independently by three technicians using a linear, nominal scale. Quantitatively, a ratio of movement to limb size (%Move) provided a measure of movement artifact. A repeat-scan subsample (n=46) was examined to determine %Move’s impact on bone parameters. Results Agreement between measurers was strong (ICC = .732 for tibia, .812 for femur), but greater variability was observed in scans rated 3 or 4, the delineation between repeat or no repeat. The quantitative approach found ?95% of subjects had %Move <25%. Comparison of initial and repeat scans by groups above and below 25% initial movement, showed significant differences in the >25% grouping. Conclusions A pQCT visual inspection scale can be a reliable metric of image quality but technicians may periodically mischaracterize subject motion. The presented quantitative methodology yields more consistent movement assessment and could unify procedure across laboratories. Data suggest a delineation of 25% movement for determining whether a diaphyseal scan is viable or requires repeat. PMID:24077875

  17. The Effects of Stress Mitigation on Nondestructive Examination

    SciTech Connect

    Dennis C. Kunerth; Eric D. Larsen; Timothy R. Mcjunkin; Arthur D. Watkins

    2004-08-01

    Ultrasonic volumetric and eddy current and visual profile surface inspections of the completed weld securing the outer lid of the Yucca Mountain waste package are required after stress mitigation. However, the technique implemented may affect the ability of the different evaluation techniques to properly characterize the completed weld. An evaluation was performed to determine the extent the nondestructive evaluation techniques are affected by two candidate mitigation processes: controlled plasticity burnishing and laser peening. This report describes the work performed and summarizes the results.

  18. Shear Evaluation by Quantitative Flow Visualization Near the Casing Surface of a Centrifugal Blood Pump

    NASA Astrophysics Data System (ADS)

    Nishida, Masahiro; Yamane, Takashi; Tsukamoto, Yuki; Ito, Kazuyuki; Konishi, Yoshiaki; Masuzawa, Toru; Tsukiya, Tomonori; Endo, Seiko; Taenaka, Yoshiyuki

    To clarify the correlation between high-shear flow and hemolysis in blood pumps, detail shear velocity distribution was quantified by an experimental method with a model centrifugal blood pump that has a series data of hemolysis tests and computational fluid dynamic analyses. Particular attention was paid to the shear velocity near the casing surface in the volute where the high shear causes in circumferentially wide region that is considerable to cause high hemolysis. Three pump models were compared concern with the radial gap width between the impeller and casing (the radial volute width) also with the outlet position whereas the impeller geometry was identical. These casing geometries were as follows: model 1-the gap width is standard 3mm and the outlet locates to make a smooth geometrical connection with the volute, model 2-the gap width is small 0.5mm and the outlet locates to make the smooth geometrical connection with the volute, and model 3-the gap width is small 0.5mm and the outlet locates to hardly make the smooth geometrical connection with the volute but be similar radial position with that of model 1. Velocity was quantified with a particle tracking velocimetry that is one of the quantitative flow visualization techniques, and the shear velocity was calculated. Results showed that all large shear velocity existed within the layers of about 0.1mm from the casing surface and that those layers were hardly affected by a vane passage even if the gap width is 0.5mm. They also showed that the maximum shear velocity appeared on the casing surface, and the shear velocities of models 2 and 3 were almost twice as large as that of model 1. This finding is in full corresponding with the results of hemolysis tests which showed that the hemolysis levels of both models 2 and 3 were 1.5 times higher than that of model 1. These results suggest that detailed high-shear evaluation near the casing surface in the volute is one of the most important keys in estimating the hemolysis of a centrifugal blood pump.

  19. Evaluation of internal control for gene expression in Phalaenopsis by quantitative real-time PCR.

    PubMed

    Yuan, Xiu-Yun; Jiang, Su-Hua; Wang, Mo-Fei; Ma, Jie; Zhang, Xian-Yun; Cui, Bo

    2014-07-01

    The selection of appropriate reference genes is one of the most important steps to obtain reliable results for normalizing quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) of MADS-box gene in Phalaenopsis. In this study, we cloned 12 candidate reference genes including 18S ribosomal RNA (18S), elongation factor 1 alpha (EF1?), cytoskeletal structural protein actin (ACT1, ACT2, ACT3, ACT4, ACT5), ubiquitin protein (UBQ1 and UBQ2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and the cytoskeletal structural proteins ?-tubulin (TUA) and ?-tubulin (TUB) in Phalaenopsis and evaluated their expression reliability. The expression of these candidate reference genes was analyzed using geNorm and normFinder software packages; the results showed that ACT2 and ACT4 were the highest stability reference genes for all experiment sets based on normFinder, followed by ACT1 or ACT3, while ACT3 and ACT4 were the highest stability reference genes for most experiment sets based on geNorm, then TUB or others. Taken together, Actin genes were the higher stability reference genes for all tissues at total developmental stages, and similar results came from analysis by normFinder. According to geNorm analysis, ACT3 and ACT4 were the most stable reference genes for all tissues tested and tissues at reproductive stages; TUB and ACT5 or ACT4 were the most stable reference genes for vegetative tissues or roots. The most stable reference genes for all vegetative tissues and only leaves were ACT4 and ACT5, ACT2 and ACT3, respectively; ACT1 and ACT3 were the most stable genes and sufficient for reliable normalization of flower tissues. While EF1?, UBQ1, UBQ2, and GAPDH were found to be unsuitable as a reference gene in our analysis for flower tissues, total tissues, and reproductive stages; UBQ2 and 18S were identified as the least stable reference genes for vegetative tissues at different stages, different tissues at vegetative stages; TUA and 18S were the least reliable reference genes for the samples from roots at all developmental stages. This is the first systematic report on the selection of reference genes in Phalaenopsis, and these data will facilitate future work on gene expression in orchid. PMID:24811734

  20. Quantitative multi-modal NDT data analysis

    NASA Astrophysics Data System (ADS)

    Heideklang, René; Shokouhi, Parisa

    2014-02-01

    A single NDT technique is often not adequate to provide assessments about the integrity of test objects with the required coverage or accuracy. In such situations, it is often resorted to multi-modal testing, where complementary and overlapping information from different NDT techniques are combined for a more comprehensive evaluation. Multi-modal material and defect characterization is an interesting task which involves several diverse fields of research, including signal and image processing, statistics and data mining. The fusion of different modalities may improve quantitative nondestructive evaluation by effectively exploiting the augmented set of multi-sensor information about the material. It is the redundant information in particular, whose quantification is expected to lead to increased reliability and robustness of the inspection results. There are different systematic approaches to data fusion, each with its specific advantages and drawbacks. In our contribution, these will be discussed in the context of nondestructive materials testing. A practical study adopting a high-level scheme for the fusion of Eddy Current, GMR and Thermography measurements on a reference metallic specimen with built-in grooves will be presented. Results show that fusion is able to outperform the best single sensor regarding detection specificity, while retaining the same level of sensitivity.

  1. Evaluation of right and left ventricular function by quantitative blood-pool SPECT (QBS): comparison with conventional methods and quantitative gated SPECT (QGS).

    PubMed

    Odagiri, Keiichi; Wakabayashi, Yasushi; Tawarahara, Kei; Kurata, Chinori; Urushida, Tsuyoshi; Katoh, Hideki; Satoh, Hiroshi; Hayashi, Hideharu

    2006-10-01

    Though quantitative ECG-gated blood-pool SPECT (QBS) has become a popular tool in research settings, more verification is necessary for its utilization in clinical medicine. To evaluate the reliability of the measurements of left and right ventricular functions with QBS, we performed QBS, as well as first-pass pool (FPP) and ECG-gated blood-pool (GBP) studies on planar images in 41 patients and 8 healthy volunteers. Quantitative ECG-gated myocardial perfusion SPECT (QGS) was also performed in 30 of 49 subjects. First, we assessed the reproducibility of the measurements of left and right ventricular ejection fraction (LVEF, RVEF) and left and right ventricular end-diastolic volume (LVEDV, RVEDV) with QBS. Second, LVEF and RVEF obtained from QBS were compared with those from FPP and GBP, respectively. Third, LVEF and LVEDV obtained from QBS were compared with those from QGS, respectively. The intra- and inter-observer reproducibilities were excellent for LVEF, LVEDV, RVEF and RVEDV measured with QBS (r = 0.88 to 0.96, p < 0.01), while the biases in the measurements of RVEF and RVEDV were relatively large. LVEF obtained from QBS correlated significantly with those from FPP and GBP, while RVEF from QBS did not. LVEF and LVEDV obtained from QBS were significantly correlated with those from QGS, but the regression lines were not close to the lines of identity. In conclusion, the measurements of LVEF and LVEDV with QBS have good reproducibility and are useful clinically, while those of RVEF and RVEDV are less useful compared with LVEF and LVEDV. The algorithm of QBS for the measurements of RVEF and RVEDV remains to be improved. PMID:17134018

  2. Evaluation of biangular reflection photometry for quantitative study of etched alloy surface roughness.

    PubMed

    Kelly, J R; Brantley, W A

    1987-08-01

    Biangular reflection photometry was correlated with quantitative stereology and direct pit-depth measurements for an electrolytically etched nickel-chromium-beryllium alloy. Effects of viewing angle, viewing aperture, and plane polarization of incident and viewing light were also studied. The results showed that architectural changes in the etched metal surface could be quantitatively described with the use of reflection photometry. An off-specular peak, located at an angle of reflection considerably different from the angle of incidence, was observed to have an intensity comparable with that of the specular reflection peak. Viewing aperture was found to affect one's ability to distinguish among degrees of surface roughness. PMID:3305636

  3. Evaluating a quantitative methionine requirement for juvenile Pacific white shrimp Litopenaeus vannamei

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 10-wk feeding trial was conducted as a third study (all conducted in our laboratory) to determine a quantitative requirement of juvenile Litopenaeus vannamei for sulfur amino acid methionine. Juvenile shrimp (mean weight 0.61 +/- 0.13 g) were reared in 110-L aquaria in a seawater recirculating sy...

  4. Extensions and evaluations of a general quantitative theory of forest structure and dynamics

    Microsoft Academic Search

    Brian J. Enquist; Geoffrey B. West; James H. Brown

    2009-01-01

    Here, we present the second part of a quantitative theory for the structure and dynamics of forests under demographic and resource steady state. The theory is based on individual-level allometric scaling relations for how trees use resources, fill space, and grow. These scale up to determine emergent properties of diverse forests, including size-frequency distributions, spacing relations, canopy configurations, mortality rates,

  5. Quantitative serum free light chain assay in the diagnostic evaluation of AL amyloidosis

    Microsoft Academic Search

    HARUN AKAR; DAVID C. SELDIN; BARBARAJEAN MAGNANI; JOHN L. BERK; CHRISTOPHER SCHOONMAKER; HOWARD CABRAL; LAURA M. DEMBER; VAISHALI SANCHORAWALA; LAWREEN H. CONNORS; RODNEY H. FALK; MARTHA SKINNER

    We compared a new serum immunoassay for quantitation of serum free light chains (FLC) with the conventional tests for clonal immunoglobulin production: bone marrow immunohistochemistry, serum immunofixation electrophoresis, and urine immunofixation electrophoresis. Serum samples from 169 patients with AL amyloidosis and 20 controls were examined. Elevated levels of k-FLC and l-FLC were found in 94% and 93% of patients with

  6. Magnetoneurography: recording biomagnetic fields for quantitative evaluation of isolated rat sciatic nerves

    Microsoft Academic Search

    Xander Smit; B. Stefan de Kool; Erik T. Walbeehm; E. B. Michiel Dudok van Heel; Johan W. van Neck; Steven E. R. Hovius

    2003-01-01

    Magnetoneurography (MNG) is a technique to record the biomagnetic action fields of peripheral nerves. The benefits of MNG in contrast to electroneurography include the decreased signal disturbance caused by surrounding biological tissues and the use of a calibration pulse, both of which contribute to high reproducibility. MNG has proven to be a valuable tool to quantitate peripheral nerve regeneration in

  7. Quantitative Evaluation of Matching Methods and Validity Measures for Stereo Vision

    Microsoft Academic Search

    Jasmine Banks; Peter I. Corke

    2001-01-01

    The authors present a qualitative and quantitative comparison of various similarity measures that form the kernel of common area-based stereo-matching systems. The authors compare classical difference and correlation measures as well as nonparametric measures based on the rank and census transforms for a number of outdoor images. For robotic applications, important considerations include robustness to image defects such as intensity

  8. Quantitatively assessing the vulnerability of critical information systems: A new method for evaluating security enhancements

    Microsoft Academic Search

    Sandip C. Patel; James H. Graham; Patricia A. S. Ralston

    2008-01-01

    This paper proposes a new approach for assessing the organization's vulnerability to information-security breaches. Although much research has been done on qualitative approaches, the literature on numerical approaches to quantify information-security risk is scarce. This paper suggests a method to quantify risk in terms of a numeric value or “degree of cybersecurity”. To help quantitatively measure the level of cybersecurity

  9. Evaluation of Quantitative Analysis of Cultures from Sonicated Retrieved Orthopedic Implants in Diagnosis of Orthopedic Infection

    Microsoft Academic Search

    Jaime Esteban; Enrique Gomez-Barrena; Jose Cordero; Nieves Zamora Martõ ´ n-de-Hijas; Teemu J. Kinnari; Ricardo Fernandez-Roblas

    To improve the microbiological diagnosis of device-related osteoarticular infections, we have developed a protocol based on the sonication of device samples, followed by concentration and inoculation of the sonicate in a broad variety of media in a quantitative manner. Sixty-six samples from 31 patients were included in the study (17 of them with clinical diagnosis of infection). The sonication procedure

  10. An evaluation of quantitative and qualitative assessment techniques on the impact of the SERR curriculum.

    PubMed

    Christenson, P D

    1985-05-01

    This study measured the effectiveness of a smoking risk reduction program for sixth grade students using a pretest/posttest control group design with the addition of a nonequivalent control group. Knowledge of the health consequences of smoking, decision-making, resistance-to-persuasion skills, and tobacco use were analyzed quantitatively; program implementation, participant views of the program, and program effects were analyzed qualitatively; and the quantitative data were analyzed in terms of its consistency with the qualitative data. Analysis of quantitative results revealed significant differences between groups on the smoking knowledge test, decision-making skills, and resistance-to-persuasion skills. Qualitative results not only substantiated quantitative results, but also revealed overall participant satisfaction with the program. They also indicated the need for a close working relationship between teachers, state and local health educators, reorganization of the curriculum, and relinquishing of curriculum to school districts for self-scheduling and organization. Utilization of both methods of analysis yielded a closer estimate of total program impact than if only method of analysis had been used. PMID:3847678

  11. Evaluation of a new automated microneutralization assay for the quantitative detection of neutralizing antibodies against enteroviruses.

    PubMed

    Rabenau, H; Weber, B

    1994-03-01

    An automated microneutralization assay for the quantitative detection of neutralizing antibodies (NA) against polioviruses and non-polio enteroviruses (NPEV) using a pipetting roboter (Tecan RSP 5072) was established and compared to the conventional manually performed test procedure. The qualitative neutralizing antibody detection was not significantly influenced by the assay system (manual or automated assay). Concerning the quantitative antibody detection, two-fold titre differences between the two test systems were observed in only 2.3% of the 260 serum samples investigated. The intra-assay and inter-assay variability of the quantitative detection of neutralizing antibodies using the automated assay proved to be very low. The quantitative detection of neutralizing antibodies using an automated pipetting robot permitted the testing of large numbers of samples within a shorter period and with less labour intensity as compared to the manually performed assay. Therefore it represents a valuable alternative to the conventional microneutralization test, especially for the serodiagnosis of non-polio enterovirus infections in large sample collectives, assessment of immunity to polioviruses and for seroepidemiological surveys. PMID:8061415

  12. Qualitative and quantitative evaluation of MODIS satellite sensor data for regional and urban scale air quality

    Microsoft Academic Search

    Jill A. Engel-Cox; Christopher H. Holloman; Basil W. Coutant; Raymond M. Hoff

    2004-01-01

    Advances in satellite sensors have provided new datasets for monitoring air quality at urban and regional scales. Qualitative true color images and quantitative aerosol optical depth data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on the Terra satellite were compared with ground-based particulate matter data from US Environmental Protection Agency (EPA) monitoring networks covering the period from 1 April

  13. Qualitative and quantitative evaluation of Simon™, a new CE-based automated Western blot system as applied to vaccine development.

    PubMed

    Rustandi, Richard R; Loughney, John W; Hamm, Melissa; Hamm, Christopher; Lancaster, Catherine; Mach, Anna; Ha, Sha

    2012-09-01

    Many CE-based technologies such as imaged capillary IEF, CE-SDS, CZE, and MEKC are well established for analyzing proteins, viruses, or other biomolecules such as polysaccharides. For example, imaged capillary isoelectric focusing (charge-based protein separation) and CE-SDS (size-based protein separation) are standard replacement methods in biopharmaceutical industries for tedious and labor intensive IEF and SDS-PAGE methods, respectively. Another important analytical tool for protein characterization is a Western blot, where after size-based separation in SDS-PAGE the proteins are transferred to a membrane and blotted with specific monoclonal or polyclonal antibodies. Western blotting analysis is applied in many areas such as biomarker research, therapeutic target identification, and vaccine development. Currently, the procedure is very manual, laborious, and time consuming. Here, we evaluate a new technology called Simple Western™ (or Simon™) for performing automated Western analysis. This new technology is based on CE-SDS where the separated proteins are attached to the wall of capillary by a proprietary photo activated chemical crosslink. Subsequent blotting is done automatically by incubating and washing the capillary with primary and secondary antibodies conjugated with horseradish peroxidase and detected with chemiluminescence. Typically, Western blots are not quantitative, hence we also evaluated the quantitative aspect of this new technology. We demonstrate that Simon™ can quantitate specific components in one of our vaccine candidates and it provides good reproducibility and intermediate precision with CV <10%. PMID:22965727

  14. Journal of Nondestructive Evaluation, Vol. 25, No. 1, March 2006 (C 2006) DOI: 10.1007/s10921-006-0003-8

    E-print Network

    Nagy, Peter B.

    -006-0003-8 Eddy Current Assessment of Near-Surface Residual Stress in Shot-Peened Inhomogeneous Nickel: 5/16/06 Recently, it has been shown that shot-peened nickel-base superalloys exhibit an ap variation adversely affects the accuracy of residual stress evaluation in shot-peened and subsequently

  15. A TEM quantitative evaluation of strengthening in an Mg-RE alloy reinforced with SiC

    SciTech Connect

    Cabibbo, Marcello, E-mail: m.cabibbo@univpm.it; Spigarelli, Stefano

    2011-10-15

    Magnesium alloys containing rare earth elements are known to have high specific strength, good creep and corrosion resistance up to 523 K. The addition of SiC ceramic particles strengthens the metal matrix composite resulting in better wear and creep resistance while maintaining good machinability. The role of the reinforcement particles in enhancing strength can be quantitatively evaluated using transmission electron microscopy (TEM). This paper presents a quantitative evaluation of the different strengthening contributions, determined through TEM inspections, in an SiC Mg-RE composite alloy containing yttrium, neodymium, gadolinium and dysprosium. Compression tests at temperatures ranging between 290 and 573 K were carried out. The microstructure strengthening mechanism was studied for all the compression conditions. Strengthening was compared to the mechanical results and the way the different contributions were combined is also discussed and justified. - Research Highlights: {yields} TEM yield strengthening terms evaluation on a Mg-RE SiC alloy. {yields} The evaluation has been extended to different compression temperature conditions. {yields} Linear and Quadratic sum has been proposed and validated. {yields} Hall-Petch was found to be the most prominent strengthening contributions.

  16. Nondestructive verification and assay systems for spent fuels. Technical appendixes

    SciTech Connect

    Cobb, D.D.; Phillips, J.R.; Baker, M.P.

    1982-04-01

    Six technical appendixes are presented that provide important supporting technical information for the study of the application of nondestructive measurements to spent-fuel storage. Each appendix addresses a particular technical subject in a reasonably self-contained fashion. Appendix A is a comparison of spent-fuel data predicted by reactor operators with measured data from reprocessors. This comparison indicates a rather high level of uncertainty in previous burnup calculations. Appendix B describes a series of nondestructive measurements at the GE-Morris Operation Spent-Fuel Storage Facility. This series of experiments successfully demonstrated a technique for reproducible positioning of fuel assemblies for nondestructive measurement. The experimental results indicate the importance of measuring the axial and angular burnup profiles of irradiated fuel assemblies for quantitative determination of spent-fuel parameters. Appendix C is a reasonably comprehensive bibliography of reports and symposia papers on spent-fuel nondestructive measurements to April 1981. Appendix D is a compendium of spent-fuel calculations that includes isotope production and depletion calculations using the EPRI-CINDER code, calculations of neutron and gamma-ray source terms, and correlations of these sources with burnup and plutonium content. Appendix E describes the pulsed-neutron technique and its potential application to spent-fuel measurements. Although not yet developed, the technique holds the promise of providing separate measurements of the uranium and plutonium fissile isotopes. Appendix F describes the experimental program and facilities at Los Alamos for the development of spent-fuel nondestructive measurement systems. Measurements are reported showing that the active neutron method is sensitive to the replacement of a single fuel rod with a dummy rod in an unirradiated uranium fuel assembly.

  17. Interfacial evaluation of modified Jute and Hemp fibers\\/polypropylene (PP)-maleic anhydride polypropylene copolymers (PP-MAPP) composites using micromechanical technique and nondestructive acoustic emission

    Microsoft Academic Search

    Joung-Man Park; Son Tran Quang; Byung-Sun Hwang; K. Lawrence DeVries

    2006-01-01

    Interfacial evaluation of the untreated and treated Jute and Hemp fibers reinforced different matrix polypropylene-maleic anhydride polypropylene copolymer (PP-MAPP) composites was investigated by micromechanical technique combined with acoustic emission (AE) and dynamic contact angle measurement. For the statistical tensile strength of Jute and Hemp fibers, bimodal Weibull distribution was fitted better than the unimodal distribution. The acid–base parameter on the

  18. Space shuttle: Structural integrity and assessment study. [development of nondestructive test procedures for space shuttle vehicle

    NASA Technical Reports Server (NTRS)

    Pless, W. M.; Lewis, W. H.

    1974-01-01

    A study program was conducted to determine the nondestructive evaluation (NDE) requirements and to develop a preliminary nondestructive evaluation manual for the entire space shuttle vehicle. The rationale and guidelines for structural analysis and NDE requirements development are discussed. Recommendations for development of NDE technology for the orbiter thermal protection system and certain structural components are included. Recommendations to accomplish additional goals toward space shuttle inspection are presented.

  19. Rice and cold stress: methods for its evaluation and summary of cold tolerance-related quantitative trait loci

    PubMed Central

    2014-01-01

    Cold stress adversely affects rice (Oryza sativa L.) growth and productivity, and has so far determined its geographical distribution. Dissecting cold stress-mediated physiological changes and understanding their genetic causes will facilitate the breeding of rice for cold tolerance. Here, we review recent progress in research on cold stress-mediated physiological traits and metabolites, and indicate their roles in the cold-response network and cold-tolerance evaluation. We also discuss criteria for evaluating cold tolerance and evaluate the scope and shortcomings of each application. Moreover, we summarize research on quantitative trait loci (QTL) related to cold stress at the germination, seedling, and reproductive stages that should provide useful information to accelerate progress in breeding cold-tolerant rice. PMID:25279026

  20. A Quantitative Evaluation of Fixed-Pattern Noise Reduction Methods in Imaging Systems

    Microsoft Academic Search

    Pablo Meza; César San Martín; Esteban Vera; Sergio N. Torres

    2010-01-01

    \\u000a Fixed-pattern noise is a common feature in several uncalibrated imaging systems, and it typically appears as striping and\\u000a grid-like nonuniformity artifacts in hyperspectral and infrared cameras. In this work, we present a quantitative and comparative\\u000a analysis of fixed-pattern noise reduction, or calibrating techniques, by using several image quality indexes. A special emphasis\\u000a is made in demonstrating the correspondence between the