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1

Quantitative nondestructive evaluation  

Microsoft Academic Search

Quantitative Nondestructive Evaluation (QNDE) provides techniques to assess deterioration of a material or a structure, and to detect and characterize discrete flaws. It plays, therefore, an important role in the prevention of failure. QNDE techniques are used in processing, manufacturing and for in-service inspection. QNDE is particularly important for the in-service inspection of high-cost and critical load-bearing structures whose failure

J. D Achenbach

2000-01-01

2

Quantitative nondestructive evaluation: Requirements for tomorrow's reliability  

NASA Technical Reports Server (NTRS)

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.

Heyman, Joseph S.

1991-01-01

3

Nondestructive evaluation  

SciTech Connect

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.

Martz, H.E.

1997-02-01

4

Quantitative magneto-optic imager for nondestructive evaluation  

NASA Astrophysics Data System (ADS)

Magneto-Optical Imagers (MOI) appear to be good alternatives to conventional eddy current sensors for defect detection in large metallic structures. Indeed, they allow short time inspection of large structures such as airplanes fuselage or wings, thanks to the visualization of "real time" images relative to the presence of defects [1]. The basic principle of the MOI is to combine a magnetic inductor, used to induce the circulation of eddy currents into the structure under test, with an optical set-up used to image the resultant magnetic field, thanks to the Faraday effect occurring in a magneto-optical garnet. The MOI designed by G. L. Fitzpatrick and Physical Research Instrumentation provides two-level images relative to the presence of defects, with an adjustable detection threshold. These so-called qualitative images, although highly contrasted, are rather poor and limited in terms of defect characterization possibilities. In, this paper, the authors present a new kind of MOI, called Quantitative Magneto-Optical Imager (Q-MOI), based on the use of a dedicated "linear" magneto-optical garnet associated with a specific instrumentation. The Q-MOI should considerably reduce the inspection time and allow to fully characterize the encountered defects. First images obtained with a demonstration prototype are shown for surface and buried flaws and further enhancements of the device are proposed.

Pinassaud, Jean; Joubert, Pierre-Yves; Lemistre, Michel

2005-05-01

5

Review of Advances in Quantitative Eddy Current Nondestructive Evaluation  

Microsoft Academic Search

A comprehensive review of advancements in eddy current (EC) modeling is presented. This paper contains three main sections: a general treatise of EC theory, the thin skin EC forward modeling, and the EC inverse problem. (1) The general treatise of eddy current theory begins with an exposition of the reciprocity formulas for evaluating probe impedance changes, which are derivable from

B. A. Auld; J. C. Moulder

1999-01-01

6

Quantitative non-destructive evaluation of composite materials based on ultrasonic parameters  

NASA Technical Reports Server (NTRS)

Research into the nondestructive evaluation of advanced reinforced composite laminates is summarized. The applicability of the Framers-Kronig equations to the nondestructive evaluation of composite materials is described.

Miller, James G.

1987-01-01

7

Nondestructive evaluations  

SciTech Connect

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

Kulkarni, S.

1993-03-01

8

Nondestructive evaluations  

NASA Astrophysics Data System (ADS)

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

Kulkarni, S.

1993-03-01

9

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

NASA Technical Reports Server (NTRS)

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.

Miller, J. G.

1986-01-01

10

Quantitative non-destructive evaluation of high-temperature superconducting materials  

SciTech Connect

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.

Achenbach, J.D.

1991-06-14

11

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

NASA Technical Reports Server (NTRS)

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

Miller, James G.

1993-01-01

12

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

NASA Technical Reports Server (NTRS)

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.

Miller, James G.

1997-01-01

13

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

NASA Technical Reports Server (NTRS)

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.

Miller, James G.

1998-01-01

14

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

15

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

SciTech Connect

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.

Achenbach, J.D.

1991-06-14

16

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

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

17

[Nondestructive Evaluation (NDE) Capabilities  

NASA Technical Reports Server (NTRS)

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)

Born, Martin

2010-01-01

18

SQUIDs for nondestructive evaluation  

Microsoft Academic Search

We attempt a comprehensive review of all published research in nondestructive evaluation (NDE) performed with the superconducting quantum interference device (SQUID) magnetometer since the first work was reported in the mid-1980s. The SQUID is the most sensitive detector of magnetic flux known. The energy sensitivity of the SQUID may make it the most sensitive detector of any kind. The research

W G Jenksy; Amir Kabir

1997-01-01

19

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

NASA Technical Reports Server (NTRS)

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

Miller, James G.

1988-01-01

20

Nondestructive evaluation technique guide  

NASA Technical Reports Server (NTRS)

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.

Vary, A.

1973-01-01

21

NONDESTRUCTIVE DAMAGE EVALUATION OF ELECTRO-MECHANICAL COMPONENTS USING A HYBRID,  

E-print Network

NONDESTRUCTIVE DAMAGE EVALUATION OF ELECTRO-MECHANICAL COMPONENTS USING A HYBRID, COMPUTATIONAL, a novel hybridized use of nondestructive, noninvasive, remote, full field of view, quantitative opto and computational modeling provides an effective engineering tool for nondestructive study of electro

Furlong, Cosme

22

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

NASA Technical Reports Server (NTRS)

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

Miller, James G.

1992-01-01

23

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

NASA Technical Reports Server (NTRS)

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.

Miller, James G.

1995-01-01

24

Overview of nondestructive evaluation technologies  

SciTech Connect

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.

Thomas, G.

1995-04-01

25

Magnetoresistive Sensors for Nondestructive Evaluation  

Microsoft Academic Search

New high-sensitivity solid-state magnetoresistive (MR) sensor technologies offer significant advantages in nondestructive evaluation (NDE) systems. A key advantage of MR sensors is a flat frequency response extending from dc to hundreds of MHz, making them particularly attractive for low-frequency and multi- frequency eddy current detection for deep-flaw detection and depth profiling. MR sensors are mass produced by thin film processing

Albrecht Jander; Carl Smith; Robert Schneider

26

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

NASA Technical Reports Server (NTRS)

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

Miller, James G.

1990-01-01

27

Nondestructive evaluation of structural ceramics  

NASA Technical Reports Server (NTRS)

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.

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

1987-01-01

28

Symposium on Nondestructive Evaluation, 12th, San Antonio, Tex., April 24-26, 1979, Proceedings  

Microsoft Academic Search

A collection of papers is presented regarding the research, development, and application achievements in the area of nondestructive testing. Topics of interest include computer signal processing for ultrasonic attenuation and velocity measurements, nondestructive measurement of plate glass temper, a proposed time-domain quantitative ultrasonic NDE system, and nondestructive evaluation techniques for composite materials. Also discussed are computer-controlled ultrasonic inspection of magnetic

W. W. Bradshaw

1979-01-01

29

Nondestructive evaluation of structural ceramics  

NASA Technical Reports Server (NTRS)

Research on nondestructive evaluation (NDE) of structural ceramics for heat engine applications is reviewed. Microfocus radiography and scanning laser acoustic microscopy are the NDE techniques highlighted. The techniques were applied to research samples of sintered silicon nitride and silicon carbide in the form of modulus-of-rupture (MOR) bars. The strength and limitations of the aforementioned techniques are given in terms of probablility of detection for voids in green and sintered MOR bars. Voids for this purpose were introduced by seeding green ceramic bars and characterizing each void in terms of its size, shape, location, and nature before and after sintering. The effects of material density, microstructure, surface finish, thickness, void depth, and size characteristics on detectability are summarized.

Vary, Alex

1986-01-01

30

Assessment of and standardization for quantitative nondestructive test  

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

31

Quantitative nondestructive characterization of visco-elastic materials at high pressure  

SciTech Connect

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

Aizawa, Tatsuhiko; Kihara, Junji [Univ. of Tokyo (Japan). Dept. of Metallurgy; Ohno, Jun [Hitachi, Ltd., Odawara (Japan)

1995-11-01

32

Acoustic imaging for nondestructive evaluation  

Microsoft Academic Search

The application of acoustic imaging techniques to non-destructive testing (NDT) of materials is discussed. After a description of the standard NDT techniques employed in the field and some examples of mechanically scanned imaging devices, most of the paper is devoted to a description of electronically scanned and focused systems. As holographic techniques are described by Ahmed et al. [22] in

G. S. Kino

1979-01-01

33

Electromagnetic Imaging Methods for Nondestructive Evaluation Applications  

PubMed Central

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

Deng, Yiming; Liu, Xin

2011-01-01

34

Nondestructive Evaluation of Aircraft and Spacecraft Wiring  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

35

Fast Geometric Algorithms for Tomographic Nondestructive Evaluation  

E-print Network

Fast Geometric Algorithms for Tomographic Nondestructive Evaluation Peyman Milanfar SRI and application of a novel approach to fast non- destructive evaluation (NDE) via direct estimation of signi cant NDE is an important part of many industrial processes. NDE techniques and equipment have been

Milanfar, Peyman

36

Nondestructive quantitative stress characterization of wire rope and steel cables  

NASA Astrophysics Data System (ADS)

This paper describes a new approach to nondestructive and quantitative characterization of residual and applied stress (absolute stress) on wire rope and steel cable. Examples are given from both field work as well as laboratory tests, including stress characterization of post-tensioning cables, bridge suspension cables, wire rope and thin strand steel wire. The approach is based on x-ray diffraction techniques. A detailed description of the results and the methodologies used to obtain them are provided.

Brauss, Michael E.; Pineault, James A.; Belassel, M.; Teodoropol, Stefan I.

1998-03-01

37

Nondestructive Evaluation of Ageing Steel Structures  

Microsoft Academic Search

Usually, materials are inspected by nondestructive methods to detect and evaluate defects that may cause failure under the designed operation conditions. However, the structure may also fail due to uncertainties of material properties like strength or hardness, and may also suffer from unexpected degradation during operation. A reliable NDE technique for detecting the inception of failure during early stages of

Iris Altpeter; Michael Kröning

38

Nondestructive Evaluation of Plates Using Eddy Current Methods  

E-print Network

Nondestructive Evaluation of Plates Using Eddy Current Methods David C. Dobson \\Lambda Department is a nondestructive evaluation technique to detect flaws in metalic specimens. It has found prevalent use in aircraft­93­1­0500 and grant F49620­95­1­0305. 1 #12; While this nondestructive evaluation method has been quite effective

Santosa, Fadil

39

Nondestructive Evaluation of Plates Using Eddy Current Methods  

E-print Network

Nondestructive Evaluation of Plates Using Eddy Current Methods David C. Dobson Department is a nondestructive evaluation technique to detect aws in metalic specimens. It has found prevalent use in aircraft this nondestructive evaluation method has been quite e ective in detecting the presence of aws, it is generally

Dobson, David C.

40

Nondestructive Evaluation of Plates Using Eddy Current Methods  

E-print Network

Nondestructive Evaluation of Plates Using Eddy Current Methods David C. Dobson Department current method is a nondestructive evaluation technique to detect aws in metalic specimens. It has found-93-1-0500 and grant F49620-95-1-0305. 1 #12;While this nondestructive evaluation method has been quite eective

41

MULTIPLE SENSOR PERIODIC NONDESTRUCTIVE EVALUATION OF A CONCRETE BRIDGE DECK  

E-print Network

MULTIPLE SENSOR PERIODIC NONDESTRUCTIVE EVALUATION OF A CONCRETE BRIDGE DECK J. Cui1 , D.R. Huston2 results of periodically multiple sensor nondestructive testing of a reinforced concrete slab experiment. In the last few decades, a variety of nondestructive evaluation techniques and methods emerged

Huston, Dryver R.

42

Nondestructive Evaluation of Adhesively Bonded Joints  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

43

Magnetoresistive sensors for nondestructive evaluation (Invited Paper)  

Microsoft Academic Search

New high-sensitivity solid-state magnetoresistive (MR) sensor technologies offer significant advantages in nondestructive evaluation (NDE) systems. A key advantage of MR sensors is a flat frequency response extending from dc to hundreds of MHz, making them particularly attractive for low-frequency and multi-frequency eddy current detection for deep-flaw detection and depth profiling. MR sensors are mass produced by thin film processing techniques

Albrecht Jander; Carl Smith; Robert Schneider

2005-01-01

44

Nondestructive evaluation of sintered ceramics  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

45

Nondestructive evaluation of nuclear-grade graphite  

SciTech Connect

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.

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

46

Nondestructive dynamic testing of apples for firmness evaluation  

Microsoft Academic Search

Two nondestructive dynamic test methods, low-mass impact and acoustic response, were tested and compared with destructive compression and penetration tests to evaluate apple firmness. The purpose of the study was to analyze the performance of the impact test methods for nondestructive firmness evaluation, and to assess whether the acoustic tests could add sorting capacity to low-mass impact testing in apples.

I Shmulevich; N Galili; M. S Howarth

2003-01-01

47

A Consortium of the United States Council for Automotive Research Nondestructive Evaluation Steering Committee  

E-print Network

A Consortium of the United States Council for Automotive Research Nondestructive Evaluation Steering Committee Strategic Plan for Nondestructive Evaluation Development in the North American #12;Cover Photo: Pictured is a modern use of Nondestructive Evaluation for ensuring paint quality

Knowles, David William

48

Data Fusion Techniques of Multiple Sensors Nondestructive Evaluation of a Concrete Bridge Deck  

E-print Network

Data Fusion Techniques of Multiple Sensors Nondestructive Evaluation of a Concrete Bridge Deck J decades, nondestructive evaluation (NDE) methods have been applied widely and significantly on concrete of reinforced steel rebars, cracks, voids, etc. Various commercial nondestructive evaluation techniques

Huston, Dryver R.

49

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

NASA Technical Reports Server (NTRS)

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

Pless, W. M.

1974-01-01

50

Applications of the wavefield transform to nondestructive evaluation  

Microsoft Academic Search

Eddy current nondestructive techniques offer many attractive benefits such as reduced inspection time, low cost and reproducibility. Nevertheless, they are not used in many industrial applications, primarily due to the difficulty associated with the lack of simple and physically meaningful interpretation techniques. In contrast; wave propagation phenomena based non-destructive evaluation (NDE) techniques employ a host of physical intuitive concepts, among

Yong Tian

2005-01-01

51

Nondestructive evaluation development for process control  

SciTech Connect

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

Ellingson, W.A.; Holloway, D.L.; Sivers, E.A. [Argonne National Lab., IL (United States); Ling, J. [Chinese Academy of Science, Shanghai SH (China). Inst. for Ceramics; Pollinger, J.P.; Yeh, H.C. [Allied-Signal Aerospace Co., Torrance, CA (United States). Garrett Ceramic Components Div.

1991-12-31

52

Nondestructive evaluation development for process control  

SciTech Connect

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

Ellingson, W.A.; Holloway, D.L.; Sivers, E.A. (Argonne National Lab., IL (United States)); Ling, J. (Chinese Academy of Science, Shanghai SH (China). Inst. for Ceramics); Pollinger, J.P.; Yeh, H.C. (Allied-Signal Aerospace Co., Torrance, CA (United States). Garrett Ceramic Components Div.)

1991-01-01

53

A Modeling-Based Technique for Nondestructive Evaluation of Metal Powders Undergoing Microwave Sintering  

E-print Network

A Modeling-Based Technique for Nondestructive Evaluation of Metal Powders Undergoing Microwave, microwave imaging, neural network applications, nondestructive testing. I. INTRODUCTION Microwave (MW the development of suitable means of nondestructive evaluation (NDE) of powder samples under microwave 978

Yakovlev, Vadim

54

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

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

55

Nondestructive Evaluation Correlated with Finite Element Analysis  

NASA Technical Reports Server (NTRS)

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

Abdul-Azid, Ali; Baaklini, George Y.

1999-01-01

56

Guided wave nuances for ultrasonic nondestructive evaluation.  

PubMed

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

Rose, J L

2000-01-01

57

Nondestructive Evaluation of Metal Fatigue Using Nonlinear Acoustics  

NASA Technical Reports Server (NTRS)

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.

Cantrell, John H., Jr.

2008-01-01

58

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...

59

Development of nondestructive evaluation methods for structural ceramics  

Microsoft Academic Search

Development of nondestructive evaluation (NDE) methods for application to fossil energy systems continues in three areas: (a) mapping axial and radial density gradients in hot gas filters, (b) characterization of the quality of continuous fiber ceramic matrix composite (CFCC) joints and (c) characterization and detection of defects in thermal barrier coatings. In this work, X-ray computed tomographic imaging was further

W. A. Ellingson; R. D. Koehl; J. B. Stuckey; J. G. Sun; H. P. Engel; R. G. Smith

1997-01-01

60

A global optimization technique for microwave nondestructive evaluation  

Microsoft Academic Search

A global optimization technique based on a genetic algorithm is proposed for microwave nondestructive evaluation. Starting from an integral formulation of the inverse scattering problem, the detection of a flaw in a known host medium is reduced to the minimization of a suitable nonlinear functional relating the measured field to the field predicted at a given iteration. The geometrical parameters

Matteo Pastorino; Salvatore Caorsi; Andrea Massa

2002-01-01

61

A review of SQUID magnetometry applied to nondestructive evaluation  

Microsoft Academic Search

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.

Harold Weinstock; Bolling AFB

1991-01-01

62

Need for Nondestructive Evaluation (NDE) in the Detection of Decay in Structures1  

E-print Network

Need for Nondestructive Evaluation (NDE) in the Detection of Decay in Structures1 W. Wayne Wilcox2 Abstract: Examples of the need for nondestructive and remote sensing technologies for evaluating existing technologies. Sometimes, nondestructive evaluation (NDE) is not needed to determine

Standiford, Richard B.

63

An inverse problem in nondestructive evaluation of Elisa Francini, Thomas Hoftand Fadil Santosa  

E-print Network

An inverse problem in nondestructive evaluation of spot-welds Elisa Francini, Thomas Hoftand Fadil arises in a novel nondestructive evaluation technique for assessing the quality of a spot-weld. We devise;Nondestructive evaluation of spot-welds 2 z x transducer weld nugget sheet metals infrared camera Figure 1

Santosa, Fadil

64

Hyperspectral imaging for nondestructive evaluation of tomatoes  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

65

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

E-print Network

Hertzian contact transducers for nondestructive evaluation F. L. Degertekin and B. T. Khuri plates through a Hertzian contact. As a particular application to nondestructive evaluation, accu- rate, misalignment of fibers, etc.3 Lamb waves are the dominantly used ultrasonic wave modes for nondestructive

Khuri-Yakub, Butrus T. "Pierre"

66

Materials and Nondestructive Evaluation Laboratoriers: User Test Planning Guide  

NASA Technical Reports Server (NTRS)

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.

Schaschl, Leslie

2011-01-01

67

Development of nondestructive evaluation methods for structural ceramics  

Microsoft Academic Search

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

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

1996-01-01

68

Development of nondestructive evaluation methods for structural ceramics  

Microsoft Academic Search

During the past year, the focus of our work on nondestructive evaluation (NDE) methods was on the development and application of these methods to technologies such as ceramic matrix composite (CMC) hot-gas filters, CMC high-temperature heat exchangers, and CMC ceramic\\/ceramic joining. Such technologies are critical to the ''Vision 21 Energy-Plex Fleet'' of modular, high-efficiency, low-emission power systems. Specifically, our NDE

Ellingson

1998-01-01

69

Recent developments in nondestructive evaluation for structural ceramics  

Microsoft Academic Search

Advanced nondestructive evaluation methods are being developed to characterize ceramic materials and allow improvement of process technology. If one can determine porosity, map organic binder\\/plasticizer distributions, measure average through-volume and in-plane density, as well as detect inclusions, then process and machine operations may be modified to enhance the reliabilty of ceramics. Two modes of x-ray tomographic imaging - advanced film

W. A. Ellingson; R. A. Roberts; M. W. Vannier; J. L. Ackerman; B. D. Sawicka; S. Gronemeyer; R. J. Kriz

1987-01-01

70

Nondestructive Characterization of Quantitative Bonding Strength at a Bonded Solid-Solid Interface  

NASA Astrophysics Data System (ADS)

We propose a nondestructive method to characterize the quantitative bonding strength at a bonded solid-solid interface by a contact acoustic nonlinearity (CAN) microscope. The principle of the CAN microscope is briefly described. The vibration amplitude of the incident focusing wave at the bonded interface is calculated, the standard bonding strength with a complete bonding state is established by the tension test, and the CAN parameter is calibrated. The quantitative contour of bonding strength at the interface could be obtained. The experimental contours of two samples are also presented.

Chen, Jian-Jun; Zhang, De; Mao, Yi-Wei; Cheng, Jian-Chun

2011-08-01

71

Neural network analysis of nondestructive evaluation patterns  

Microsoft Academic Search

Nondeabuctive evaluation (NDE) teelmiques are used to verify the integrity of aircraft parts prior to assembly, during assembly, and during maintenance operations. These tec.hniqueaare used to ensure that matedal flaws do not exist in critical structural parts. Current NDE technologies are being challenged by demands for increased aeeuracy, sreliability, and cost effectiveness. The objective of this reaearch was to develop

W. E. Bond; D. C. St. Clair; M. M. Amirfathi; C. J. Merz; S. Aylward

1992-01-01

72

Nondestructive Evaluation Quality Procedure: Personnel Qualification and Certification Radiographic Testing-Levels I& II  

SciTech Connect

This Operational Procedure establishes the minimum requirements for the qualification and certification/recertification of Nondestructive Evaluation (NDE) personnel in the nondestructive testing (NDT) radiographic testing (RT) method. This document is in accordance with the American Society for Nondestructive Testing Recommended Practice SNT-TC-1A, 1996, except as amended herein.

Dolan, K; Rikard, R D; Rodriquez, J

2003-07-01

73

Porosity evaluation of PoSi wafer using a nondestructive ultrasonic technic  

E-print Network

Porosity evaluation of PoSi wafer using a nondestructive ultrasonic technic J. Bustilloa , J measurement methods of PoSi are currently destructive. Therefore in this study a nondestructive ultrasonic travelling through it, ultrasonic non-destructive testing can be a good way to measure these parameters [9

Boyer, Edmond

74

Efficient Nondestructive Evaluation of Prototype Carbon Fiber Reinforced Structures  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

75

Nondestructive evaluation of Ni-Ti shape memory alloy  

SciTech Connect

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.

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

76

Nondestructive Evaluation of Ni-Ti Shape Memory Alloy  

NASA Astrophysics Data System (ADS)

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.

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

2011-06-01

77

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

SciTech Connect

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

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

1998-09-01

78

Liberty Bell 7 Recovery Evaluation and Nondestructive Testing  

NASA Technical Reports Server (NTRS)

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.

Madaras, Eric I.; Smith, William L.

1999-01-01

79

A review of SQUID magnetometry applied to nondestructive evaluation  

SciTech Connect

This paper reports on 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. This presentation will review the preliminary studies of this application within the past few years in order to serve as an introduction to those that follow. It will include early work by the author which explored the ability of a SQUID to detect defects in a buried pipe and to detect fatigue in steel structures.

Weinstock, H. (Air Force Office of Scientific Research, Bolling AFB, DC (United States))

1991-03-01

80

Efficient methods for solving boundary integral equation in diffusive scalar problem and eddy current nondestructive evaluation.  

E-print Network

??Eddy current nondestructive evaluation (NDE) of airframe structures involves the detection of electromagnetic field irregularities due to non-conducting inhomogeneities in an electrically conducting material. Usually,… (more)

Yang, Ming

2010-01-01

81

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

E-print Network

PRESSURE BAG MOLDING: MANUFACTURING, MECHANICAL TESTING, NON-DESTRUCTIVE EVALUATION, AND ANALYSIS..........................................................................................................4 Pressure Bag Molding-up ..............................................................................................................13 Resin Transfer Molding

82

Nondestructive evaluation of Polymer Coating Structures on Pharmaceutical Pellets using Full Field Optical Coherence Tomography  

E-print Network

confirmed all these findings. The presented FF-OCT approach is inexpensive and has better spatial resolution compared to other non-destructive analysis techniques such as terahertz pulsed imaging, and is thus considered advantageous for the quantitative...

Li, C; Zeitler, J. A; Dong, Y; Shen, Y.-C

83

Acoustic wave generation by microwaves and applications to nondestructive evaluation.  

PubMed

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

Hosten, Bernard; Bacon, Christophe; Guilliorit, Emmanuel

2002-05-01

84

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

NASA Technical Reports Server (NTRS)

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.

Roberts, Mark J. (Compiler)

1999-01-01

85

Induction thermography for non-destructive evaluation of adhesive bonds  

NASA Astrophysics Data System (ADS)

Adhesive bonding is widely used in automotive industry in the recent times. One of the major problems with adhesive bonds is the lack of a suitable non-destructive evaluation technique for assessing bonding. In this paper, an experimental study was carried out to apply induction thermography technique to evaluate adhesively bonded steel plates. Samples were fabricated with artificial defects such as air gap, foreign material, and improper adhesive filling. Induction thermography technique was found to detect defects and foreign inclusions. The sample specimen was also inspected using standard techniques such as Ultrasonic testing and Radiography testing. Defect detecting capabilities of the three techniques are compared. Induction thermography heating was FE modelled in 3D using COMSOL 3.5a. The simulated Induction thermography model was compared and validated with experimental results.

Balaji, L.; Balasubramaniam, Krishnan; Krishnamurthy, C. V.

2013-01-01

86

Application of Raman Spectroscopy for Nondestructive Evaluation of Composite Materials  

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

87

Acoustic diagnosis for nondestructive evaluation of ceramic coatings on steel substrates  

SciTech Connect

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

Aizawa, Tatsuhiko; Kihara, Junji [Univ. of Tokyo (Japan). Dept. of Metallurgy; Ito, Manabu [Toppan Co. Ltd., Saitama (Japan)

1995-11-01

88

Remote monitoring and nondestructive evaluation of wind turbine towers  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

89

Infrared non-destructive evaluation method and apparatus  

DOEpatents

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.

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

2014-10-21

90

Nondestructive evaluation of aircraft composites using terahertz time domain spectroscopy  

NASA Astrophysics Data System (ADS)

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

Stoik, Christopher D.

91

Nondestructive Evaluation Methodologies Developed for Certifying Composite Flywheels  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

92

Physical model assisted probability of detection in nondestructive evaluation  

SciTech Connect

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

Li, M.; Meeker, W. Q. [Center for Nondestructive Evaluation and Department of Statistics, Iowa State University, Ames, IA 50011 (United States); Thompson, R. B. [Center for Nondestructive Evaluation, Iowa State University, Ames, IA 50011 (United States)

2011-06-23

93

Wavelet-based deconvolution of ultrasonic signals in nondestructive evaluation  

E-print Network

In this paper, the inverse problem of reconstructing reflectivity function of a medium is examined within a blind deconvolution framework. The ultrasound pulse is estimated using higher-order statistics, and Wiener filter is used to obtain the ultrasonic reflectivity function through wavelet-based models. A new approach to the parameter estimation of the inverse filtering step is proposed in the nondestructive evaluation field, which is based on the theory of Fourier-Wavelet regularized deconvolution (ForWaRD). This new approach can be viewed as a solution to the open problem of adaptation of the ForWaRD framework to perform the convolution kernel estimation and deconvolution interdependently. The results indicate stable solutions of the estimated pulse and an improvement in the radio-frequency (RF) signal taking into account its signal-to-noise ratio (SNR) and axial resolution. Simulations and experiments showed that the proposed approach can provide robust and optimal estimates of the reflectivity function.

Herrera, Roberto Henry; Rodríguez, Manuel

2012-01-01

94

Microwave Nondestructive Evaluation of Dielectric Materials with a Metamaterial Lens  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

95

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

SciTech Connect

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

B.Mi; X. Zhao; R. Bayles

2006-05-26

96

Super-resolution image reconstruction for ultrasonic nondestructive evaluation.  

PubMed

Ultrasonic testing is one of the most successful nondestructive evaluation (NDE) techniques for the inspection of carbon-fiber-reinforced polymer (CFRP) materials. This paper discusses the application of the iterative backprojection (IBP) super-resolution image reconstruction technique to carbon epoxy laminates with simulated defects to obtain high-resolution images for NDE. Super-resolution image reconstruction is an approach used to overcome the inherent resolution limitations of an existing ultrasonic system. It can greatly improve the image quality and allow more detailed inspection of the region of interest (ROI) with high resolution, improving defect evaluation and accuracy. First, three artificially simulated delamination defects in a CFRP panel were considered to evaluate and validate the application of the IBP method. The results of the validation indicate that both the contrast-tonoise ratio (CNR) and the peak signal-to-noise ratio (PSNR) value of the super-resolution result are better than the bicubic interpolation method. Then, the IBP method was applied to the low-resolution ultrasonic C-scan image sequence with subpixel displacement of two types of defects (delamination and porosity) which were obtained by the micro-scanning imaging technique. The result demonstrated that super-resolution images achieved better visual quality with an improved image resolution compared with raw C-scan images. PMID:24297023

Li, Shanglei; Chu, Tsuchin Philip

2013-12-01

97

High resolution ultrasonic spectroscopy system for nondestructive evaluation  

NASA Technical Reports Server (NTRS)

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

Chen, C. H.

1991-01-01

98

Quantitative Evaluation Of Teleoperator Performance  

NASA Technical Reports Server (NTRS)

Report describes experiments on remote manual control of robotic manipulator. Experiments conducted to evaluate quantitatively relative effectiveness of several control modes: various combinations of position control, rate control, remote compliance, and feedback from force and torque sensors. Tasks evaluated: removing thermal blanket, unbolting electrical panel, and handling bundles of electrical wires and electrical connectors on simulated solar Max satellite by means of remotely controlled robot in teleoperation laboratory.

Das, Hari; Zak, Haya; Kim, Won S.; Bejczy, Antal K.; Schenker, Paul S.

1992-01-01

99

Nondestructive evaluation techniques for nickel-cadmium aerospace battery cells  

NASA Technical Reports Server (NTRS)

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

Haak, R.; Tench, D.

1982-01-01

100

Nondestructive evaluation of hydrogel mechanical properties using ultrasound  

PubMed Central

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

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

101

Research in nondestructive evaluation techniques for nuclear reactor concrete structures  

SciTech Connect

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.

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

2014-02-18

102

Research in nondestructive evaluation techniques for nuclear reactor concrete structures  

NASA Astrophysics Data System (ADS)

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

Clayton, Dwight; Smith, Cyrus

2014-02-01

103

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

NASA Technical Reports Server (NTRS)

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.

Walker, James L.

1998-01-01

104

The thermographic nondestructive evaluation of iron aluminide green sheet  

NASA Astrophysics Data System (ADS)

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

Watkins, Michael Lee

105

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

NASA Technical Reports Server (NTRS)

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

Madaras, Eric

2001-01-01

106

Laser-induced focused ultrasound for nondestructive testing and evaluation  

NASA Astrophysics Data System (ADS)

Focused ultrasound pulses generated by photoacoustic transformation at a metal surface immersed in water possess a pronounced compression phase on the nanosecond time scale. For 8 ns laser pump pulses, the spectrum of the initially generated ultrasonic pulse covered a frequency range between 0.1 and 150 MHz. A concave spherical geometry of the light-absorbing metal surface can be used to achieve focusing. In the present experiments a conical ultrasound beam was directed at a solid glass plate or silicon wafer, where the tilt of the normal of the metal mirror defined the efficiency of mode conversion at the water-solid interface. Depending on the configuration, focused bulk waves as well as Rayleigh and Lamb waves could be launched in the sample with this setup. The laser probe-beam-deflection method was employed for local detection of elastic disturbances at the sample surface. Due to the nonlinear elastic response of water and harmonics generation, frequencies >100 MHz were realized, despite a strong attenuation in this frequency range. Gradual increase of the laser power density from 5 to 14 MW/cm2 led to shock formation in the compressive pressure pulse in water and shortening of the Rayleigh pulse induced at the surface of the glass plate. The observed transient surface profiles were highly sensitive to nearby mechanical discontinuities such as a microcrack in glass or an edge discontinuity in silicon. Therefore, laser-induced focused ultrasound seems to be a very promising method of accomplishing diverse tasks of nondestructive evaluation.

Kozhushko, Victor V.; Hess, Peter

2008-06-01

107

Non-Destructive Evaluation of Materials via Ultraviolet Spectroscopy  

NASA Technical Reports Server (NTRS)

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.

Pugel, Betsy

2008-01-01

108

Investigation of capacitively coupled ultrasonic transducer system for nondestructive evaluation.  

PubMed

Capacitive coupling offers a simple solution to wirelessly probe ultrasonic transducers. This paper investigates the theory, feasibility, and optimization of such a capacitively coupled transducer system (CCTS) in the context of nondestructive evaluation (NDE) applications. The noncontact interface relies on an electric field formed between four metal plates-two plates are physically connected to the electrodes of a transducer, the other two are in a separate probing unit connected to the transmit/receive channel of the instrumentation. The complete system is modeled as an electric network with the measured impedance of a bonded piezoelectric ceramic disc representing a transducer attached to an arbitrary solid substrate. A transmission line model is developed which is a function of the physical parameters of the capacitively coupled system, such as the permittivity of the material between the plates, the size of the metal plates, and their relative positions. This model provides immediate prediction of electric input impedance, pulse-echo response, and the effect of plate misalignment. The model has been validated experimentally and has enabled optimization of the various parameters. It is shown that placing a tuning inductor and series resistor on the transmitting side of the circuit can significantly improve the system performance in terms of the signal-to-crosstalk ratio. Practically, bulk-wave CCTSs have been built and demonstrated for underwater and through-composite testing. It has been found that electrical conduction in the media between the plates limits their applications. PMID:24297024

Zhong, Cheng Huan; Wilcox, Paul D; Croxford, Anthony J

2013-12-01

109

Development of nondestructive evaluation methods for structural ceramics  

SciTech Connect

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.

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

110

Development of nondestructive evaluation methods for structural ceramics.  

SciTech Connect

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

Ellingson, W. A.

1998-08-19

111

Nondestructive Evaluation Methods for the Ares I Common Bulkhead  

NASA Technical Reports Server (NTRS)

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

Walker, James

2010-01-01

112

Synchronized Electronic Shutter System (SESS) for Thermal Nondestructive Evaluation  

NASA Technical Reports Server (NTRS)

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

Zalameda, Joseph N.

2001-01-01

113

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

E-print Network

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) ...

Ortega, Jose Alberto, 1978-

2006-01-01

114

Ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials  

E-print Network

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 ...

Wang, Ji-yong, 1967-

2003-01-01

115

Development of nondestructive evaluation methods for structural ceramics  

SciTech Connect

Development of nondestructive evaluation (NDE) methods for application to fossil energy systems continues in three areas: (a) mapping axial and radial density gradients in hot gas filters, (b) characterization of the quality of continuous fiber ceramic matrix composite (CFCC) joints and (c) characterization and detection of defects in thermal barrier coatings. In this work, X-ray computed tomographic imaging was further developed and used to map variations in the axial and radial density of two full length (2.3-m) hot gas filters. The two filters differed in through wall density because of the thickness of the coating on the continuous fibers. Differences in axial and through wall density were clearly detected. Through transmission infrared imaging with a highly sensitivity focal plane array camera was used to assess joint quality in two sets of SiC/SiC CFCC joints. High frame rate data capture suggests that the infrared imaging method holds potential for the characterization of CFCC joints. Work to develop NDE methods that can be used to evaluate electron beam physical vapor deposited coatings with platinum-aluminide (Pt-Al) bonds was undertaken. Coatings of Zirconia with thicknesses of 125 {micro}m (0.005 in.), 190 {micro}m (0.0075 in.), and 254 {micro}m (0.010 in.) with a Pt-Al bond coat on Rene N5 Ni-based superalloy were studied by infrared imaging. Currently, it appears that thickness variation, as well as thermal properties, can be assessed by infrared technology.

Ellingson, W.A.; Koehl, R.D.; Stuckey, J.B.; Sun, J.G. [Argonne National Lab., IL (United States). Energy Technology Div.; Engel, H.P. [Heaviside Science, Inc., Melbourne, FL (United States); Smith, R.G. [3M Corp., St. Paul, MN (United States)

1997-06-01

116

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

E-print Network

A UTILITY EVALUATION OF NONDESTRUCTIVE TESTING DEVICES USED ON ASPHALT CONCRETE PAVEMENTS A Thesis by SHELLEY MARIE STOFFELS Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1986 Major Subject: Civil Engineering A UTILITY EVALUATION OF NONDESTRUCTIVE TESTING DEVICES USED ON ASPHALT CONCRETE PAVEMENTS A Thesis by SHELLEY MARIE STOFFELS Approved as to style and content by: Robe L. Lytt red...

Stoffels, Shelley Marie

1986-01-01

117

Quantitative nondestructive density determinations of very low-density carbon foams  

SciTech Connect

The carbon density and the carbon distribution in low-density foams that were manufactured by a modified salt-replica process were determined by bulk measurements of weight and volume and by x-ray computed tomography (CT). When determining the carbon density, both methods yielded similar results, however, the high spatial resolution of CT was found to yield nondestructive quantitative information on the carbon distribution that was not available from bulk measurements. The highest and lowest foam densities were found to occur at the edges and the interior, respectively. The carbon density at the edge was found to be a few percent up to 20 percent higher than the average foam density. The percentage of carbon buildup at the edge was determined to be inversely proportional to the foal density, and in addition, the gradient compared favorably with calculations from Fick's second low of diffusion. A calculated diffusion coefficient was interpreted in terms of foam manufacturing in the modified salt-replica process. 6 refs., 5 figs., 1 tab.

Moddeman, W.E.; Kramer, D.P.; Firsich, D.W.; Trainer, P.D.; Back, P.S.; Smith, S.D.; Deal, W.R.; Salerno, R.F.; Koehler, F.A. (EG and G Mound Applied Technologies, Miamisburg, OH (United States)); Hughes, M.E.; Yancey, R.N. (Advanced Research and Applications Corp., Dayton, OH (United States))

1991-01-01

118

Smart Structures and Materials & Nondestructive Evaluation and Health Monitoring; 17th Annual International symposium, 7-11 March 2010; San Diego, California USA  

E-print Network

Smart Structures and Materials & Nondestructive Evaluation and Health Monitoring; 17th Annual noninvasive types of health monitoring or nondestructive techniques to detect hidden flaws and mini cracks

Oza, Nikunj C.

119

Nondestructive Evaluation for the Space Shuttle's Wing Leading Edge  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

120

Rapid Prototyping Integrated With Nondestructive Evaluation and Finite Element Analysis  

NASA Technical Reports Server (NTRS)

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

Abdul-Aziz, Ali; Baaklini, George Y.

2001-01-01

121

Journal of Nondestructive Evaluation, Vol. 23, No. 3, September 2004 ( C 2004) Eddy Current Assessment of Near-Surface Residual  

E-print Network

Journal of Nondestructive Evaluation, Vol. 23, No. 3, September 2004 ( C 2004) Eddy Current for nondestructive residual stress assessment of subsurface residual stresses. It has been found that the primary stress considerations are incorporated into the life prediction methodology. Nondestructive inspection

Nagy, Peter B.

122

A Quantitative Evaluation of Symmetry Detection Algorithms  

E-print Network

A Quantitative Evaluation of Symmetry Detection Algorithms Po-Chun Chen1 , James Hays2 , Seungkyu. This paper presents a sys- tematic, quantitative evaluation of rotation, reflection and translation sym-defined quantitative evaluation scheme for an effective validation and comparison of different symmetry detection

123

Nondestructive evaluation of load transfer at rigid airport pavement joints  

Microsoft Academic Search

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

Michael I. Hammons

1995-01-01

124

Forensic Examination Using a Nondestructive Evaluation Method for Surface Metrology  

Microsoft Academic Search

The objective of this paper is to describe the use of a new technique of optical profilometry in a nondestructive, non-contact fashion for the comparison of two metallic surfaces, one hard and one soft. When brought in contact with one another, the harder material (i.e. the tool) will impress its surface roughness onto the softer. It is understood that the

David J. Eisenmann; L. Scott Chumbley

2009-01-01

125

FORENSIC EXAMINATION USING A NONDESTRUCTIVE EVALUATION METHOD FOR SURFACE METROLOGY  

Microsoft Academic Search

The objective of this paper is to describe the use of a new technique of optical profilometry in a nondestructive, non-contact fashion for the comparison of two metallic surfaces, one hard and one soft. When brought in contact with one another, the harder material (i.e. the tool) will impress its surface roughness onto the softer. It is understood that the

David J. Eisenmann; L. Scott Chumbley

2009-01-01

126

Nondestructive evaluation of distributed damage in graphite/epoxy beams using modal parameters  

E-print Network

NONDESTRUCTIVE EVALUATIOV OF DISTRIBUTED DAMAGE IN GRAPHITE/EPOXY BEAMS USING MODAL PARAMETERS A Thesis YOUNG IK KIM Submitted to the Office of Graduate Studies of Texas AkM University in partial fulfillment of the requirement for the degree.... Sanders (Chairman of Committee) David H. Allen (Member) Norris D. Stubbs (Member) Alton . Highsmith (Member) Walter E. Haisler (Head of Department) August 1989 ABSTRACT Nondestructive Evaluation of Distributed Damage in Graphite/Epoxy Beams...

Kim, Young Ik

1989-01-01

127

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

NASA Technical Reports Server (NTRS)

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.

Generazio, Edward R.; Roth, Don J.

1990-01-01

128

Quantitative evaluation of Alzheimer's disease  

NASA Astrophysics Data System (ADS)

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.

Duchesne, S.; Frisoni, G. B.

2009-02-01

129

Non-destructive evaluation techniques for prosthetic heart valves based on hologram interferometry. Part I.  

PubMed

The development of a technique applying hologram interferometry, which is a non-destructive, non-contact, full-field, highly sensitive method is reported. The valve under investigation is placed in a test chamber which has windows providing optical access. Deformations of the valve leaflets due to pressure loading are recorded by hologram interferometry. The resulting interferogram clearly indicates the existence of any defects or structural anomalies which may be present in the valve material. Three modifications to this technique, intended for qualitative and quantitative non-destructive valve screening tests are described. The proposed technique is expected to become an effective means of detecting hidden defects of replacement heart valves; it is thus considered as a prospective tool for quality control, particularly in the manufacture of bioprosthetic valves, where initial sites of late calcification and degeneration might be identified. The application of holographic non-destructive testing may therefore substantially improve the quality and durability of heart valve substitutes. PMID:8269147

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

1993-07-01

130

Nondestructive Evaluation of Ceramic Matrix Composite Combustor Components  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

131

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

SciTech Connect

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.

Greenberg, M.; Ebel, D.S. (AMNH)

2009-03-19

132

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

PubMed

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

Li, Minghui; Hayward, Gordon

2012-01-01

133

Nondestructive evaluation of load transfer at rigid airport pavement joints  

NASA Astrophysics Data System (ADS)

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.

Hammons, Michael I.

1995-07-01

134

Nondestructive evaluation of concrete structures by nonstationary thermal wave imaging  

NASA Astrophysics Data System (ADS)

Reinforced concrete structures (RCS) have potential application in civil engineering and with the advent of nuclear engineering RCS to be capable enough to withstanding a variety of adverse environmental conditions. However, failures/loss of durability of designed structures due to premature reinforcement corrosion of rebar is a major constrain. Growing concern of safety of structure due to pre-mature deterioration has led to a great demand for development of non-destructive and non-contact testing techniques for monitoring and assessing health of RCS. This paper presents an experimental investigation of rebar corrosion by non-stationary thermal wave imaging. Experimental results have been proven, proposed approach is an effective technique for identification of corrosion in rebar in the concrete samples.

Mulaveesala, Ravibabu; Panda, Soma Sekhara Balaji; Mude, Rupla Naik; Amarnath, Muniyappa

2012-06-01

135

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

NASA Astrophysics Data System (ADS)

Quantitative calculation of the isotopic masses of fissionable U and Pu is important for forensic analysis of nuclear materials. ?-spectrometry is the most commonly applied tool for qualitative detection and analysis of key radionuclides in nuclear materials. Relative isotopic measurement of U and Pu may be obtained from ?-spectra through application of special software such as MGAU (Multi-Group Analysis for Uranium, LLNL) or FRAM (Fixed-Energy Response Function Analysis with Multiple Efficiency, LANL). If the concentration of U/Pu in the matrix is unknown, however, isotopic masses cannot be calculated. At present, active neutron interrogation is the only practical alternative for non-destructive quantification of fissionable isotopes of U and Pu. An active well coincidence counter (AWCC), an alternative for analyses of uranium materials, has the following disadvantages: 1) The detection of small quantities (?100 g) of 235U is not possible in many models; 2) Representative standards that capture the geometry, density and chemical composition of the analyzed unknown are required for precise analysis; and 3) Specimen size is severely restricted by the size of the measuring chamber. These problems may be addressed using modified ?-spectrometry techniques based on a coaxial HPGe-detector and ISOCS software (In Situ Object Counting System software, Canberra). We present data testing a new gamma-spectrometry method uniting actinide detection with commonly utilized software, modified for application in determining the masses of the fissionable isotopes in unknown samples of nuclear materials. The ISOCS software, widely used in radiation monitoring, calculates the detector efficiency curve in a specified geometry and range of photon energies. In describing the geometry of the source-detector, it is necessary to clearly describe the distance between the source and the detector, the material and the thickness of the walls of the container, as well as material, density and chemical composition of the matrix of the specimen. Obviously, not all parameters can be characterized when measuring samples of unknown composition or uranium in bulk form. Because of this, and especially for uranium materials, the IAEA developed an ISOCS optimization procedure. The target values for the optimization are ?matrixfixed, the matrix mass determined by weighing with a known mass container, and ?fixed, the 235U enrichment, determined by MGAU. Target values are fitted by varying the matrix density (?), and the concentration of uranium in the matrix of the unknown (w). For each (?i, wi), an efficiency curve is generated, and the masses of uranium isotopes, ?235Ui and ?238Ui, determined using spectral activity data and known specific activities for U. Finally, fitted parameters are obtained for ?matrixi = ?matrixfixed ± 1?, ?i = ?fixed ± 1?, as well as important parameters (?i, wi, ?235Ui, ?238Ui, ?Ui). We examined multiple forms of uranium (powdered, pressed, and scrap UO2 and U3O8) to test this method for its utility in accurately identifying the mass and enrichment of uranium materials, and will present the results of this research.

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

2011-12-01

136

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

Microsoft Academic Search

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

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

2000-01-01

137

Nondestructive evaluation of multilayered structures using ultrasonic guided waves generated by an electromagnetic acoustic array transducer  

Microsoft Academic Search

Multilayered structures with adhesively bonded plates are a common inspection problem for nondestructive evaluation. In many cases, large areas must be inspected with limited access. One powerful method for inspecting these structures is to excite ultrasonic guided wave modes that propagate over distances of many meters and into inaccessible areas that may be embedded within another structure. The utilization of

Michael Quarry

2001-01-01

138

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

E-print Network

Non-Destructive Evaluation of Materials Using Pulsed Microwave Interrogating Signals and Acoustic using re ections of pulsed microwave interrogating signals from moving acous- tic interfaces]) that acoustic pressure waves will interact with electromagnetic signals in ways that often mimic interfacial

139

Design and evaluation of a nondestructive fissile assay device for HTGR fuel samples  

Microsoft Academic Search

Nondestructive assay of fissile material plays an important role in nuclear fuel processing facilities. Information for product quality control, plant criticality safety, and nuclear materials accountability can be obtained from assay devices. All of this is necessary for a safe, efficient, and orderly operation of a production plant. Presented here is a design description and an operational evaluation of a

S. R. McNeany; R. W. Knoll; J. D. Jenkins

1979-01-01

140

Low-frequency perturbation theory in eddy-current non-destructive evaluation  

E-print Network

Low-frequency perturbation theory in eddy-current non-destructive evaluation N. Harfield,a) Y series solutions for the impedance change in an eddy-current test probe due to closed cracks in a non structures in, for example, the nuclear power and aero- space industries. Eddy-current inspection methods

Bowler, John R.

141

Fast Solver for Large Scale Eddy Current Non-Destructive Evaluation Problems  

E-print Network

Fast Solver for Large Scale Eddy Current Non-Destructive Evaluation Problems Naiguang Lei Advisor: Lalita Udpa Thursday, July 31st, 2014 9:00-11:00am, EB2219 Abstract Eddy current testing plays a very, an alternating magnetic field source generates induced currents, called eddy currents, in an electrically

142

Recent Developments of Aircraft Nondestructive Evaluation Based on Advanced Sensor Techniques  

Microsoft Academic Search

The safety and structural integrity are of great importa nce to military and commercial aircraft, and the developments of effective nondestruct ive evaluation (NDE) methods are receiving much attention in recent years. The objective o f this paper was to provide the recent developments of aircraft NDE based on advanced sensor t echniques: (a) Ultrasonic testing with piezoceramic sensor arrays,

Gongjin QI; Hong LEI; Rongsheng GENG; Peng JING

143

Nondestructive Evaluation of Graphite-Epoxy Composites by the Laser Ultrasonic Method  

Microsoft Academic Search

A laser ultrasonic method for nondestructive evaluation of the structure of composite materials is proposed. Specimens of graphite-epoxy composites with compaction-type defects and air cavities are investigated. The method is based on the laser thermooptical generation of wide-band acoustic pulses - optoacoustic (OA) signals - in the material investigated. The acoustic pulses backscattered by structural ingomogeneities and defects are registered

A. A. Karabutov; I. M. Pelivanov; N. B. Podymova

2000-01-01

144

Contemporary ultrasonic signal processing approaches for nondestructive evaluation of multilayered structures  

Microsoft Academic Search

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

Guang-Ming Zhang; David M. Harvey

2011-01-01

145

Contemporary ultrasonic signal processing approaches for nondestructive evaluation of multilayered structures  

Microsoft Academic Search

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

Guang-Ming Zhang; David M. Harvey

2012-01-01

146

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...

147

Benchmark problems for defect size and shape determination in eddy-current nondestructive evaluation  

Microsoft Academic Search

A set of four benchmark problems is presented for verification of theoretical calculations of defect size and shape in eddy-current nondestructive evaluation. The benchmark problems are based on careful measurements of the change in coil impedance as a function of frequency for a circular air-cored coil which is scanned along the axis of an electrodischarge machined slot in a thick

D. J. Harrison; L. D. Jones; S. K. Burke

1996-01-01

148

Microwave nondestructive detection and evaluation of disbonding and delamination in layered-dielectric slabs  

Microsoft Academic Search

A microwave nondestructive technique for the detection and evaluation of disbonding and delamination in layered-dielectric-slabs backed by a conducting plate is discussed. The theoretical development of the technique is given. An incident wave illuminating such a medium is first considered, and the characteristics of the wave reflected by the metal plate are then formulated. An effective reflection coefficient whose phase

R. Zoughi; S. Bakhtiari

1990-01-01

149

Non-destructive evaluation of erosion damage on E-glass/epoxy composites  

E-print Network

Non-destructive evaluation of erosion damage on E-glass/epoxy composites N.H. Yang a , H. Nayeb strength of erosion damaged fiber-reinforced composites was developed based on monitoring the acoustic emission (AE) activity of the composite specimens during uniaxial tensile loading. The devel- oped method

Vaziri, Ashkan

150

Low velocity impact testing and nondestructive evaluation of transparent materials  

SciTech Connect

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.

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

151

Forensic Examination Using a Nondestructive Evaluation Method for Surface Metrology  

NASA Astrophysics Data System (ADS)

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

Eisenmann, David J.; Chumbley, L. Scott

2009-03-01

152

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

PubMed

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

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

2015-01-01

153

Case study of nonlinear inverse problems: mammography and nondestructive evaluation  

E-print Network

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

Kreinovich, Vladik

154

Nondestructive evaluation of helicopter rotor blades using guided Lamb modes.  

PubMed

This paper presents an application for turning and direct modes in a complex composite laminate structure. The propagation and interaction of turning modes and fundamental Lamb modes are investigated in the skin, spar and web sections of a helicopter rotor blade. Finite element models were used to understand the various mode conversions at geometric discontinuities such as web-spar joints. Experimental investigation was carried out with the help of air coupled ultrasonic transducers. The turning and direct modes were confirmed with the help of particle displacements and velocities. Experimental B-Scans were performed on damaged and undamaged samples for qualitative and quantitative assessment of the structure. A strong correlation between the numerical and experimental results was observed and reported. PMID:24210414

Chakrapani, Sunil Kishore; Barnard, Daniel; Dayal, Vinay

2014-03-01

155

Nondestructive Evaluation (NDE) Minor The NDE Minor at Iowa State University is a unique opportunity to get a multi-disciplinary engineering qualification in the  

E-print Network

Nondestructive Evaluation (NDE) Minor The NDE Minor at Iowa State University is a unique of Nondestructive Evaluation. Below is the current list of approved courses for the minor, totaling 16 required and still qualify for this important minor. Required Courses MatE/EM 362 Principles of Nondestructive

Lin, Zhiqun

156

Non-Destructive Damage Evaluation Based on Element Strain Energies  

E-print Network

evaluation theory; (2) the validation of the accuracy of the theory using exact structural deformational data generated from the static analysis of F. E. models in SAP2000; (3) the validation of the practical feasibility of the theory using approximated...

Li, Ran

2013-05-01

157

Nondestructive testing, evaluation, and rehabilitation for roadway pavement: Warren County, Mississippi, Cincinnati, Ohio, and Berkeley, California  

NASA Astrophysics Data System (ADS)

This report documents the results of one FIS technology transfer initiative: the demonstration of nondestructive pavement evaluation technology (NDT) to cooperating Federal and non-federal partners. The demonstrations utilized Falling Weight Deflectometer (FWD) technology, a commercially available nondestructive procedure for determining the structural adequacy of a pavement system. Data obtained from FWD tests were combined with pavement material properties and estimated future traffic volumes to design rehabilitation strategies for the existing streets and roadways of three communities. The specific objectives of the study were to: (1) Evaluate and develop improvements to the initial guide specification used for contracting FWD technology; (2) Evaluate the three analytical methods used by each contractor to develop the pavement repair strategies; (3) Document and explain the differences in the results of the pavement evaluation methods; (4) Document the benefits of FWD technology over other conventional techniques; and (5) Transfer nondestructive testing of pavements technology to non-federal partners, and demonstrate how analysis of the test results can be used to develop rehabilitation strategies for roadway pavements.

Grau, Richard H.; Alexander, Don R.

1994-07-01

158

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

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

159

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

SciTech Connect

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.

B. Mi; G. Zhao; R. Bayles

2006-08-10

160

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

NASA Technical Reports Server (NTRS)

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.

Roberts, Mark J. (Compiler)

1999-01-01

161

A novel, compact, low-cost, impulse ground-penetrating radar for nondestructive evaluation of pavements  

Microsoft Academic Search

This paper reports on the development of a novel, compact, low-cost, impulse ground-penetrating radar (GPR) and demonstrate its use for nondestructive evaluation of pavement structures. This GPR consists of an ultrashort-monocycle-pulse transmitter (330 ps), an ultrawide-band (UWB) sampling receiver (0-6 GHz), and two UWB antennas (0.2-20 GHz)-completely designed using microwave-integrated circuits with seamless electrical connections between them. An approximate analysis

Jeong Soo Lee; Cam Nguyen; Thomas Scullion

2004-01-01

162

Nondestructive testing ultrasonic immersion probe assessment and uncertainty evaluation according to EN 12668-2:2010.  

PubMed

Ultrasonic beam parameters from nondestructive testing probes and respective measurement uncertainties were calculated according to the Guide to the Expression of Uncertainty in Measurement (BIPM-JCGM-100:2008). The major conclusion of this work is that proper measurements of ultrasonic probes parameters are necessary because each probe has intrinsic construction particularities. Uncertainty evaluation was essential to properly assess the experimental results. PMID:23143583

Silva, Cristiane E R; Alvarenga, André V; Costa-Felix, Rodrigo P B

2012-10-01

163

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

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

164

X-ray computed tomography for nondestructive evaluation of advanced structural ceramics  

Microsoft Academic Search

This report characterizes the current status of x-ray computed tomography (CT) as applied to the nondestructive evaluation of ceramic materials. The principal advantages of x-ray CT scanning are two. The first is the capability to produce high-contrast, geometrically accurate digital pictures (images) of slices through an object with a reasonably high spatial resolution. The second is that these slice images

W. A. Ellingson; M. W. Vannier

1988-01-01

165

A comparison of deconvolution techniques for the ultrasonic nondestructive evaluation of materials  

Microsoft Academic Search

Several major deconvolution techniques commonly used for seismic applications are studied and adapted for ultrasonic NDE (nondestructive evaluation) applications. Comparisons of the relative merits of these techniques are presented based on a complete set of simulations on some real ultrasonic pulse echoes. Methods that rely largely on a reflection seismic model, such as one-at-a-time L1 spike extraction and MVD (minimum

Sam-kit Sin; Chi-hau Chen

1992-01-01

166

Model-based estimation of ultrasonic echoes. Part II: Nondestructive evaluation applications  

Microsoft Academic Search

For Part I see ibid., vol.48, no.3, pp.787-802 (2001). Accurate estimation of the ultrasonic echo pattern leading to the physical property of the object is desirable for ultrasonic NDE (nondestructive evaluation) applications. In Part I of this study, we have presented a generalized parametric ultrasonic echo model, composed of a number of Gaussian echoes corrupted by noise, and algorithms for

Ramazan Demirli; Jafar Saniie

2001-01-01

167

Remote visual inspection for nondestructive evaluation in power plants  

NASA Astrophysics Data System (ADS)

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

Samsonov, Peter

1994-02-01

168

Efficient Nondestructive Evaluation of Prototype Carbon Fiber Reinforced Structures  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

169

Infrared Contrast Analysis Technique for Flash Thermography Nondestructive Evaluation  

NASA Technical Reports Server (NTRS)

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

Koshti, Ajay

2014-01-01

170

Journal of Nondestructive Evaluation, Vol. 24, No. 4, December 2005 (C 2005) DOI: 10.1007/s10921-005-8783-9  

E-print Network

Journal of Nondestructive Evaluation, Vol. 24, No. 4, December 2005 (C 2005) DOI: 10.1007/s10921-005-8783-9 Dynamic Piezoresistivity Calibration for Eddy Current Nondestructive Residual Stress Measurements Feng Yu1. P. Blodgett and P. B. Nagy, J. Nondestruct. Eval. 23, 107 (2004)] that eddy current conductivity

Nagy, Peter B.

171

Journal of Nondestructive Evaluation, Vol. 25, No. 3, September 2006 (C 2006) DOI: 10.1007/s10921-006-0009-2  

E-print Network

Journal of Nondestructive Evaluation, Vol. 25, No. 3, September 2006 (C 2006) DOI: 10.1007/s10921 conduc- tivity (AECC), which can be exploited for nondestructive residual stress assessment. Experi are incorporated into the life prediction methodology. Nondestructive inspection of components for near

Nagy, Peter B.

172

Application of internal friction damping as a nondestructive evaluation technique for wire rope  

SciTech Connect

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 which several test parameters were changed. The test parameters including the tensile load, frequency of test load, exposure time of rope to load and variations in rope construction are discussed from the standpoint of IFD-NDE measurements.

Hochrein, A.A.; Sherrard, J.R.; Thiruvengadam, A.P.

1983-05-01

173

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

NASA Astrophysics Data System (ADS)

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.

Sugimoto, Sunao; Aoki, Takuya; Iwahori, Yutaka; Ishikawa, Takashi

2005-04-01

174

Millimeter Wave Nondestructive Evaluation of Corrosion Under Paint in Steel Structures  

SciTech Connect

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.

Kharkovsky, S.; Zoughi, R. [Applied Microwave Nondestructive Testing Laboratory (amntl), Electrical and Computer Engineering Department, University of Missouri-Rolla, Rolla, MO 65409 (United States)

2006-03-06

175

Three new nondestructive evaluation tools based on high flux neutron sources  

SciTech Connect

Nondestructive evaluation methods and systems based on specific attributes of neutron interactions with materials are being developed. The special attributes of neutrons are low attenuation in most engineering materials, strong interaction with low Z elements, and epithermal neutron absorption resonances. The three methods under development at ORNL include neutron based tomography and radiography; through thickness, nondestructive texture mapping; and internal, noninvasive temperature measurement. All three techniques require high flux sources such as the High Flux Isotope Reactor, a steady state source, or the Oak Ridge Electron Linear Accelerator, a pulsed neutron source. Neutrons are quite penetrating in most engineering materials and thus can be useful to detect internal flaws and features. Hydrogen atoms, such as in a hydrocarbon fuel, lubricant, or a metal hydride, are relatively opaque to neutron transmission and thus neutron based tomography/radiography is ideal to image their presence. Texture, the nonrandom orientation of crystalline grains within materials, can be mapped nondestructively using neutron diffraction methods. Epithermal neutron resonance absorption is being studied as a noncontacting temperature sensor. This paper highlights the underlying physics of the methods, progress in development, and the potential benefits for science and industry of the three facilities.

Hubbard, C.R.; Raine, D.; Peascoe, R.; Wright, M. [and others

1997-03-01

176

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

NASA Technical Reports Server (NTRS)

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.

McBurney, Sean

1995-01-01

177

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

NASA Technical Reports Server (NTRS)

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.

Generazio, Edward R.

1991-01-01

178

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

NASA Astrophysics Data System (ADS)

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.

Rudd, Kevin Edward

179

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

SciTech Connect

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

Shreekanth Mandayam; Robi Polikar; John C. Chen

2004-04-01

180

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

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

181

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

NASA Technical Reports Server (NTRS)

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

Walker, James L.; Richter, Joel D.

2006-01-01

182

Evaluation of Mechanical Properties of Nuclear Materials Using Non-Destructive Ball Indentation Technique  

SciTech Connect

Integrity of structural components depends on the deformation and fracture behavior of materials. For evaluating the material condition in-service, it is generally not feasible or practical or advisable to cut samples from operating structures. Non-destructive testing (NDT) techniques are required to evaluate the mechanical properties. Although several NDT techniques such as ultrasound, magnetic strength, Barkhausen noise, microhardness etc., are employed for estimating the mechanical property degradation, these methodologies are generally empirical and indirect. Automated Ball Indentation (ABI) is a non-destructive testing technique for direct measurement of mechanical and fracture properties of metallic engineering materials. Because of the small area over which the test is carried out, it is possible to determine point to point variations in the mechanical and fracture properties, such as those that exist in weldments. Although ABI technique is non-intrusive, it is a state-of-the-art mechanical test that measures directly the current/local deformation behavior of the material. In this paper, we present results from studies on the application of ABI technique to determine tensile and fracture properties of ferritic steels, an austenitic stainless steel, a nickel base superalloy and Zircaloy in different thermo-mechanical conditions. The effects of aging and cold work on these properties were determined from the ABI tests. Gradients in mechanical properties of ferritic steel welds, particularly in the narrow heat-affected zone, were clearly established. ABI technique was found to be useful in determining the anisotropy in the tensile properties of Zircaloy cladding tubes. The technique has potential as a non-destructive method for assessing structural integrity of aged components. (authors)

Mathew, M.D. [Indira Gandhi Center for Atomic Research, Kalpakkam, Tamil Nadu, 603102 (India); Linga Murty, K. [North Carolina State University, Nuclear Engineering Department, Raleigh, NC 27695-7909 (United States)

2002-07-01

183

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

NASA Technical Reports Server (NTRS)

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

Lysak, Daniel B.

2003-01-01

184

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

NASA Technical Reports Server (NTRS)

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.

Burns, Erin A.

2004-01-01

185

MUSIC-TYPE ALGORITHM FOR EDDY-CURRENT NONDESTRUC-TIVE EVALUATION OF SMALL DEFECTS IN METAL PLATES  

E-print Network

MUSIC-TYPE ALGORITHM FOR EDDY-CURRENT NONDESTRUC- TIVE EVALUATION OF SMALL DEFECTS IN METAL PLATES Eddy-Current nondestructive evaluation of metal plates is of interest in a wide range of applications in the lower frequency band (kHz) for eddy-current testing, to retrieve small void defects inside a conducting

Paris-Sud XI, Université de

186

First-year evaluation of a nondestructive assay system for the examination of ORNL TRU waste  

SciTech Connect

The Oak Ridge National Laboratory has been selected as the demonstration site for a new transuranic neutron assay system (NAS) developed at the Los Alamos National Laboratory. In addition, in order to meet specific ORNL program objectives, an upgraded segmented gamma-ray drum scanner has been integrated into the nondestructive assay (NDA) system to serve as a radioisotope identifier and as a quantitative assay backup to the NAS. A verification study, wherein selected waste drums will be emptied into glove boxes and their contents sampled and subsequently gamma-ray assayed, will take place in FY 1984. Results will be compared to those obtained from the NDA techniques. The NAS uses pulsed-neutron interrogation (differential- dieaway technique) and passive neutron measurements to determine fissile component and an upper-limit estimate of the total TRU activity contained in each waste drum. Of the 171 waste drums assayed to date, nine drums were determined to contain less than 10 nCi/g TRU isotopes. An additional number of drums (approximately 20%) are expected to be categorized as non-TRU, which is presently defined as less than 100 nCi/g TRU concentration. This requires a detailed analysis of the data which includes waste matrix compensation, systematic qualitative and quantitative gamma-ray analyses, and interpretation of neutron multiplicity data. Reproducibility of the active assay measurements on a single waste drum indicate agreement to +-3% relative error. 14 references, 24 figures, 8 tables.

Schultz, F.J.; Haff, K.W.; Coffey, D.E.; Norris, L.B.; Caldwell, J.T.; Close, D.A.; Kuckertz, T.H.; Kunz, W.E.; Pratt, J.C.

1984-04-01

187

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

SciTech Connect

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 under load and others. The report includes discussion of wire rope mechanics and application history of NDE. Also included are sections detailing IFD-NDE theory, experimental apparatus, and test technique. The data obtained in the program work is reviewed with several results and conclusions drawn. The report closes with recommendations for further work.

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

1980-05-01

188

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

PubMed

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

Her, Shiuh-Chuan; Lin, Sheng-Tung

2014-01-01

189

Experimental and numerical studies for nondestructive evaluation of human enamel using laser ultrasonic technique.  

PubMed

In this paper, a nondestructive laser ultrasonic technique is used to generate and detect broadband surface acoustic waves (SAWs) on human teeth with different demineralization treatment. A scanning laser line-source technique is used to generate a series of SAW signals for obtaining the dispersion spectrum through a two-dimensional fast Fourier translation method. The experimental dispersion curves of SAWs are studied for evaluating the elastic properties of the sound tooth and carious tooth. The propagation and dispersion of SAWs in human teeth are also been studied using the finite element method. Results from numerical simulation and experiment are compared and discussed, and the elastic properties of teeth with different conditions are evaluated by combining the simulation and experimental results. PMID:24085203

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

2013-10-01

190

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

191

Quantitative evaluation of signal integrity for magnetocardiography  

NASA Astrophysics Data System (ADS)

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

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

2009-08-01

192

Quantitative evaluation of signal integrity for magnetocardiography.  

PubMed

Magnetocardiography (MCG) is a non-invasive diagnostic tool used to investigate the activity of the heart. For applications in an unshielded environment, in order to extract the very weak signal of interest from the much higher background noise, dedicated hardware configuration and sophisticated signal processing techniques have been developed during the last decades. Being powerful in noise rejection, the signal processing may introduce signal distortions, if not properly designed and applied. However, there is a lack of an effective tool to quantitatively evaluate the signal integrity for MCG at present. In this paper, we have introduced a very simple method by using a small coil driven by a human ECG signal to generate a simulated MCG signal. Three key performance indexes were proposed, which are correlation in time domain, relative heights of different peaks and correlation in frequency domain, to evaluate the MCG system performance quantitatively. This evaluation method was applied to a synthetic gradiometer consisting of a second-order axial gradiometer and three orthogonal reference magnetometers. The evaluation turned out to be very effective in optimizing the parameters for signal processing. In addition, the method can serve as a useful tool for hardware improvement. PMID:19622849

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

2009-08-01

193

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

PubMed

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

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

2013-07-01

194

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

SciTech Connect

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

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

2009-08-01

195

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

NASA Technical Reports Server (NTRS)

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

Vary, A.

1980-01-01

196

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

NASA Astrophysics Data System (ADS)

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

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

2000-05-01

197

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

NASA Astrophysics Data System (ADS)

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.

Temple, Enoch C.

1994-10-01

198

Application of a diffusion-to-wave transformation for inverting eddy current nondestructive evaluation data  

SciTech Connect

A transformation from diffusion fields to wave fields is examined as an approach to inverting eddy current nondestructive evaluation (NDE) data. An analytic inversion to the transformation is used as a means to gain insight into robustness issues associated with the method. A discretized version of the transformation is utilized to solve a 1-D inverse problem with a direct wave-based approach. Because the transformation lacks robustness, two regularization schemes are used to stabilize the inversion, which are themselves enhanced by an averaging algorithm. The technique is shown to be unstable when applied to sources which are not ideal impulse functions, in which case the transformation can be stabilized via low-pass filtering. The transformation is not useful with time-harmonic sources and is therefore limited to pulsed eddy current inspections.

Ross, S. [Univ. of Utah, Salt Lake City, UT (United States). Dept. of Radiology] [Univ. of Utah, Salt Lake City, UT (United States). Dept. of Radiology; Lusk, M. [Colorado School of Mines, Golden, CO (United States). Div. of Engineering] [Colorado School of Mines, Golden, CO (United States). Div. of Engineering; Lord, W. [Iowa State Univ., Ames, IA (United States). Dept. of Electrical Engineering] [Iowa State Univ., Ames, IA (United States). Dept. of Electrical Engineering

1996-03-01

199

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

SciTech Connect

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.

Shreekanth Mandayam; Robi Polikar; John C. Chen

2004-04-01

200

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

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

201

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

202

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

SciTech Connect

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.

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

2011-10-03

203

Nondestructive evaluation and characterization of damage and repair to continuous-fiber ceramic composite panels.  

SciTech Connect

Continuous fiber ceramic matrix composites are currently being developed for a variety of high-temperature applications. Because of the high costs of making these components, minor damage incurred during manufacturing or operation must be rewired in order to extend the life of the components. In this study, five ceramic-grade Nicalon{trademark} fiber/SiNC-matrix composite panels were intentionally damaged with a pendulum-type impactor during an impact test. The damaged panels were then repaired at Dow Corning Corporation. Three nondestructive evaluation (NDE) methods were used to study the characteristics of the panels after the damage and again after the panels were repaired. The NDE methods were X-ray radiography, infrared thermal imaging, and air-coupled ultrasound. The results showed that the impact test induced various types of damage in the panels. The NDE data that were obtained by the three NDE methods were correlated with each other.

Sun, J. G.; Petrak, D. R.; Pillai, T. A. K.; Deemer, C.; Ellingson, W. A.

1998-04-01

204

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

NASA Technical Reports Server (NTRS)

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.

Temple, Enoch C.

1994-01-01

205

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

NASA Technical Reports Server (NTRS)

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.

Generazio, Ed

2005-01-01

206

Standard practice for digital imaging and communication nondestructive evaluation (DICONDE) for computed radiography (CR) test methods  

E-print Network

1.1 This practice facilitates the interoperability of computed radiography (CR) imaging and data acquisition equipment by specifying image data transfer and archival storage methods in commonly accepted terms. This practice 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 objec...

American Society for Testing and Materials. Philadelphia

2010-01-01

207

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

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

208

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

209

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

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

210

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

SciTech Connect

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.

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

211

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

SciTech Connect

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).

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

212

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

213

Nanomanipulation and Lithography for Carbon Nanotube Based Nondestructive Evaluation Sensor Development  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

214

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

E-print Network

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 ...

American Society for Testing and Materials. Philadelphia

2008-01-01

215

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

NASA Technical Reports Server (NTRS)

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.

Walker, James L.; Richter, Joel D.

2006-01-01

216

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

E-print Network

Studies were conducted to develop a non-destructive method for monitoring the rate of rigor mortis development in poultry and to evaluate the effectiveness of electrical stimulation (ES). In the first study, 36 male broilers in each of two trials...

Cavitt, Leslie Cain

2012-06-07

217

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

Microsoft Academic Search

Laser ultrasonic nondestructive evaluation (NDE) methods have been proposed to replace conventional in vivo dental clinical diagnosis tools that are either destructive or incapable of quantifying the elasticity of human dental enamel. In this work, a laser NDE system that can perform remote measurements on samples of small dimensions is presented. A focused laser line source is used to generate

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

2009-01-01

218

Infrared thermography non-destructive evaluation of lithium-ion battery  

NASA Astrophysics Data System (ADS)

The power lithium-ion battery with its high specific energy, high theoretical capacity and good cycle-life is a prime candidate as a power source for electric vehicles (EVs) and hybrid electric vehicles (HEVs). Safety is especially important for large-scale lithium-ion batteries, especially the thermal analysis is essential for their development and design. Thermal modeling is an effective way to understand the thermal behavior of the lithium-ion battery during charging and discharging. With the charging and discharging, the internal heat generation of the lithium-ion battery becomes large, and the temperature rises leading to an uneven temperature distribution induces partial degradation. Infrared (IR) Non-destructive Evaluation (NDE) has been well developed for decades years in materials, structures, and aircraft. Most thermographic methods need thermal excitation to the measurement structures. In NDE of battery, the thermal excitation is the heat generated from carbon and cobalt electrodes in electrolyte. A technique named "power function" has been developed to determine the heat by chemical reactions. In this paper, the simulations of the transient response of the temperature distribution in the lithium-ion battery are developed. The key to resolving the security problem lies in the thermal controlling, including the heat generation and the internal and external heat transfer. Therefore, three-dimensional modelling for capturing geometrical thermal effects on battery thermal abuse behaviour is required. The simulation model contains the heat generation during electrolyte decomposition and electrical resistance component. Oven tests are simulated by three-dimensional model and the discharge test preformed by test system. Infrared thermography of discharge is recorded in order to analyze the security of the lithium-ion power battery. Nondestructive detection is performed for thermal abuse analysis and discharge analysis.

Wang, Zi-jun; Li, Zhi-qiang; Liu, Qiang

2011-08-01

219

Nondestructive Evaluation of Advanced Materials with X-ray Phase Mapping  

NASA Technical Reports Server (NTRS)

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.

Hu, Zhengwei

2005-01-01

220

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

NASA Technical Reports Server (NTRS)

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

Fu, L. S. W.

1982-01-01

221

ECT-DATA FUSION BY THE INDEPENDENT COMPONENT ANALYSIS FOR NON-DESTRUCTIVE EVALUATION OF METALLIC SLABS  

Microsoft Academic Search

The aim of this paper is to present an application of ICA to non-destructive evaluation by unsupervised data-fusion, which aims at discovering the flaws affecting a metallic slab. The signals acquired through an eddy-current probe for non- destructive evaluation purposes are affected by strong noise and disturbances due to the mechanical system that the probe is mounted on. The availability

Simone Fiori; Pietro Burrascano

222

Development of a multi-electrode system for non-destructive and contactless wafer evaluation  

NASA Astrophysics Data System (ADS)

With the miniaturization of CMOS, the gate insulator has extremely become thin until reaching the EOT (equivalent oxide thickness) of less than 1nm in order to keep maintaining high-speed performances of devices and low electric energy consumption. Since the gate insulator is so thin, leakage current increases and the gate dielectric breakdown can easily occur. This affects the reliability of semiconductor devices. To make good devices, it is necessary to use technologies for the evaluation of the gate insulator reliability. TDDB (Time Dependent Dielectric Breakdown) lifetime has been one of the main factors for this evaluation. In this case, a wafer is destroyed in order to be evaluated, which reduces the semiconductor yield. To solve this problem, we propose a new technique for the evaluation of the gate insulator which is a non-destructive and contactless measurement method, and thus an appropriate method for inline processes. A voltage is applied on a Si/SiO2 specimen. A voltage source electrode and the specimen are not in contact (10micron gap). After it is charged, the specimen is irradiated by a xenon-flash-lamp. Since the energy of this pulsed light is beyond 4eV, electrons are emitted and move from Si to SiO2. It is possible to estimate the condition (the electrical conductivity) of the insulator using this phenomenon. A multi-electrode system was developed for mass production. With this system, one is able to evaluate 10 thousand points over a 12-inch wafer in 1 minute.

Ndagijmana, Justin; Soh, Yuki; Fukashi, Junpei; Kobayashi, K.; Furuta, Masaaki; Kubota, Hiroshi

2013-12-01

223

Dynamic laser speckle for non-destructive quality evaluation of bread  

NASA Astrophysics Data System (ADS)

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

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

2010-10-01

224

A time-domain finite element boundary integration method for ultrasonic nondestructive evaluation.  

PubMed

A 2-D and 3-D numerical modeling approach for calculating the elastic wave scattering signals from complex stress-free defects is evaluated. In this method, efficient boundary integration across the complex boundary of the defect is coupled with a time-domain finite element (FE) solver. The model is designed to simulate time-domain ultrasonic nondestructive evaluation in bulk media. This approach makes use of the hybrid concept of linking a local numerical model to compute the near-field scattering behavior and theoretical mathematical formulas for postprocessing to calculate the received signals. It minimizes the number of monitoring signals from the FE calculation so that the computation effort in postprocessing decreases significantly. In addition, by neglecting the conventional regular monitoring box, the region for FE calculation can be made smaller. In this paper, the boundary integral method is implemented in a commercial FE code, and it is validated by comparing the scattering signals with results from corresponding full FE models. The coupled method is then implemented in real inspection scenarios in both 2-D and 3-D, and the accuracy and the efficiency are demonstrated. The limitations of the proposed model and future works are also discussed. PMID:25474780

Shi, Fan; Choi, Wonjae; Skelton, Elizabeth A; Lowe, Michael J S; Craster, Richard V

2014-12-01

225

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

SciTech Connect

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

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

2002-09-19

226

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

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

227

Nondestructive evaluation of dislocation structure in cyclically deformed Ni3Fe single crystals using magnetic techniques  

NASA Astrophysics Data System (ADS)

The deformation substructure in Ni3Fe single crystals cyclically deformed at constant plastic shear strain amplitudes (?pl) consisted of two phases: the matrix with planar dislocation arrangement and the persistent slip band (PSB) having a three dimensional cell structure. The saturation stress remained almost constant regardless of ?pl by adjusting the volume fraction of PSB. Anisotropy of high-field susceptibility in cyclically deformed Ni3Fe single crystals was measured in the (111) discs. Two types of magnetic anisotropy caused by atom rearrangement near the antiphase boundary (APB) and internal stress around dislocations were observed in fatigued Ni3Fe single crystals. The anisotropy data were subjected to the Fourier-type transformation and were split into separate anisotropy functions depending on the type of lattice defects. The magnitude ratio of dislocation- to APB-dependent anisotropy increases linearly with increasing ?pl. This strongly suggests that Winter's two-phase model can be applied to both mechanical and magnetic properties. Thus, nondestructive evaluation of dislocation structure in cyclically deformed Ni3Fe single crystals could be done by analyzing the magnetic anisotropy induced by cyclic deformation.

Yasuda, Hiroyuki Y.; Sasaki, Akiko; Umakoshi, Yukichi

2003-02-01

228

Non-destructive evaluation of multilayer conductor using an HTS SQUID gradiometer  

NASA Astrophysics Data System (ADS)

We examined the ability of detecting defects in multilayer aluminum plates by using an HTS SQUID gradiometer in an unshielded environment. The planar HTS SQUID gradiometer with 1 mm × 1 mm pickup loops and 1 mm baseline was fabricated by using HTS multilayer and ramp-edge junction technologies, and cooled by thermal conduction from a LN 2 cryostat. We tried non-destructive evaluation (NDE) of a structure consisting of 5-10 layers of 2 mm thick aluminum plates with a through hole, which has a shape of slit, 30 mm in length and 0.5 mm in width only in the bottom layer, by changing the frequency of eddy current induced by a double-D type coil. It was found that the observed frequency and depth dependences of the peak gradiometer signal were well fitted by theoretical curves taking account of decay of eddy current and defect-induced magnetic field depending on the distance between the defect and the gradiometer. By employing 200 Hz frequency, the slit in the 10-layer structure could be clearly detected, indicating the ability of detecting defects located in depth more than twenty times larger than the gradiometer baseline.

Kawano, J.; Hato, T.; Adachi, S.; Oshikubo, Y.; Tsukamoto, A.; Tanabe, K.

2010-11-01

229

Comparison of ultrasonic array imaging algorithms for non-destructive evaluation  

NASA Astrophysics Data System (ADS)

Ultrasonic array imaging algorithms have been widely used and developed in nondestructive evaluation in the last 10 years. In this paper, three imaging algorithms (Total Focusing Method (TFM), Phase Coherent Imaging (PCI), and Spatial Compounding Imaging (SCI)) are compared through both simulation and experimental measurements. In the simulation, array data sets were generated using a hybrid forward model containing a single defect amongst a multitude of randomly distributed point scatterers to represent backscatter from material microstructure. The Signal to Noise Ratio (SNR) of the final images and their resolution were used to indicate the quality of the different imaging algorithms. The images of different types of defect (point reflectors and planar cracks) were used to investigate the robustness of the imaging algorithms. It is shown that PCI can yield higher image resolution than the TFM, but that the images of cracks are distorted. Overall, the TFM is the most robust algorithm across a range of different types of defects. It is also shown that the detection limit of all three imaging algorithms is almost equal for weakly scattering defects.

Zhang, J.; Drinkwater, B. W.; Wilcox, P. D.

2013-01-01

230

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

SciTech Connect

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.

Beattie, A.G.; Rumsey, M.

1998-12-17

231

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

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

232

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

PubMed

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

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

2014-12-01

233

Non-destructive evaluation of concrete with ultrasonic C-scan and digital image enhancement techniques  

NASA Astrophysics Data System (ADS)

This paper presents the results of Non-Destructive Evaluation (NDE) of concrete slabs using Ultrasonic C-Scan and image-enhancement algorithms for the detection and extraction of damage information from raw data. Two fabricated concrete slabs, one undamaged and the other with three rectangular voids were used for the test. Damage was evaluated by using ultrasonic through transmission C-Scan method. A 500 kHz transducer with pulse rates of 100 Hz to 5000 Hz was investigated to determine the best pulse rate for scanning concrete. The amplitude scan shows accurately the position of the voids present in the damaged concrete with respect to the reference edge. The results also show the inherent in-homogeneity of the concrete slab due to the presence of air pockets that invariably arise during the fabrication. Three statistical filtering techniques (Median, Mean and Gaussian) and one wavelet filtering technique were comparatively evaluated to enhance the quality of the digital image. The results show clearly the presence of the rectangular voids. Median filtering technique was the best in enhancing the image obtained from the C-Scan in terms of removing noise and preserving the details of the defects. Wavelet filtering technique was good in terms of overall noise reduction, but it resulted in loss of details of the defects producing a comparatively blurred image. This technique can be used to determine the quality of concrete at any stage in its working lifecycle thus making it a useful tool in the field of health monitoring of concrete.

Okafor, A. Chukwujekwu; Dutta, Amitabha

2014-02-01

234

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

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

235

Quantitative Ultrasonic Evaluation of Mechanical Properties of Engineering Materials  

NASA Technical Reports Server (NTRS)

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.

Vary, A.

1978-01-01

236

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

237

Experimental Evaluation in Computer Science: A Quantitative Study  

E-print Network

Experimental Evaluation in Computer Science: A Quantitative Study Paul Lukowicz, Ernst A. Heinz 400 recent research articles sug- gests that computer scientists publish relatively few papers quantitative evaluation in OE and NC is only 15 and 12, respectively. Conversely, the fraction of papers

Prechelt, Lutz

238

Experimental Evaluation in Computer Science: A Quantitative Study  

E-print Network

Experimental Evaluation in Computer Science: A Quantitative Study Paul Lukowicz, Ernst A. Heinz A survey of over 400 recent research articles sug­ gests that computer scientists publish relatively few­ tion of papers lacking quantitative evaluation in OE and NC is only 15% and 12%, respectively

Prechelt, Lutz

239

A Quantitative Evaluation of Surface Normal Estimation in Point Clouds  

E-print Network

A Quantitative Evaluation of Surface Normal Estimation in Point Clouds Krzysztof Jordan1 studied in detail in the past. We perform quantitative evaluation on a diverse set of point clouds derived.Mordohai}@stevens.edu This work was supported in part by a Google Research Award. each point of the neighborhood, or by estimating

Mordohai, Philippos

240

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

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

241

Review of embedded particle tagging methods for nondestructive evaluation (NDE) of composite materials and structures  

NASA Astrophysics Data System (ADS)

Acceptance of advanced composites in both retrofit applications and new construction necessitates quality control (QC)/quality assurance (QA) and in-service monitoring techniques to ensure the performance and serviceability of the composites. A technology that enhances the inspectability of the advanced composites is the particle tagging method. The concept of particle tagging involves embedding micron-sized particles into materials, such as composites, or adhesive layers to make them an integral part of the host material. When interrogated by suitable instrumentation, the embedded particle sensors interact with their host material and generate certain types of measurable signatures. The signatures can be correlated with the material and structural conditions, such as internal stress states, voids, inclusions, state-of- cure, and delaminations. This paper presents a technology assessment of the current and emerging state-of-the-art tagging methods. The objective of this review is to provide a framework for further understanding the physics and mechanisms involved in using the tagging method for in-field nondestructive evaluation (NDE) of composite materials. Information concerning the development of this technique has been obtained from patents, publications, databases within Newman Library at Virginia Polytechnic Institute and State University (Virginia Tech), and previous work and in-progress research at the Center for Intelligent Material Systems and Structures (CIMSS) at Virginia Tech. This paper includes a historic review of tagging techniques, a description of the tagging systems used for in-situ NDE of composites, and experimental results to date. The current and potential applications of this technique are also addressed. The analysis presented in this paper will assist in further efforts to develop the tagging approach that may be used as a new NDE technique for quality assurance of advanced composites.

Zhou, Su-Wei; Chaudhry, Zaffir A.; Rogers, Craig A.; Quattrone, Robert

1995-04-01

242

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

NASA Astrophysics Data System (ADS)

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

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

2007-01-01

243

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

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

244

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

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

245

Nondestructive quantitative mapping of impurities and point defects in thin films: Ga and VZn in ZnO:Ga  

NASA Astrophysics Data System (ADS)

Ga-doped ZnO (GZO) films grown by pulsed-laser deposition on quartz and other lattice-mismatched substrates can routinely attain resistivities of 2 × 10-4 ?.cm and thus compete with Sn-doped In2O3 (ITO) in large-area transparent-electrode applications. Nondestructive, high-resolution (1-mm) maps of thickness d, concentration n, and mobility ? on such films can be obtained automatically from commercial spectroscopic ellipsometers. From n and ?, degenerate-electron scattering theory yields donor ND and acceptor NA concentrations at each point. Finally, ND and NA can be identified as [Ga] and [VZn], respectively, demonstrating high-density mapping of impurities and point defects in a semiconductor thin film.

Look, David C.; Leedy, Kevin D.; Agresta, Donald L.

2014-06-01

246

Nondestructive Characterization of Adhesive Bonds from Guided Wave Data  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

247

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

PubMed Central

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

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

2012-01-01

248

Artificial neural networks for non-destructive evaluation with ultrasonic waves in not accessible pipes  

Microsoft Academic Search

The design of non-destructive testing systems for fault detection in long and not accessible pipelines is an actual task in the industrial and civil environment. At this purpose the diagnosis based on the propagation of guided ultrasonic waves along the pipes offers an attractive solution for the fault identification and classification. The authors studied this problem by means of suitable

Francesca Cau; Alessandra Fanni; Augusto Montisci; Pietro Testoni; Mariangela Usai

2005-01-01

249

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

250

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

NASA Technical Reports Server (NTRS)

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

Decker, Arthur J.

2004-01-01

251

A Quantitative Evaluation of Confidence Measures for Stereo Vision  

E-print Network

A Quantitative Evaluation of Confidence Measures for Stereo Vision Xiaoyan Hu, Student Member, IEEE the rapidly maturing stereo literature and that our findings would be helpful to researchers in binocular

Mordohai, Philippos

252

A Quantitative Evaluation of Confidence Measures for Stereo Vision  

E-print Network

1 A Quantitative Evaluation of Confidence Measures for Stereo Vision Xiaoyan Hu, Student Member is missing from the rapidly maturing stereo literature and that our findings would be helpful to researchers

Mordohai, Philippos

253

Evaluating the effectiveness of correlation digital speckle photography method for non-destructive testing of rough surfaces  

NASA Astrophysics Data System (ADS)

The work is devoted to the investigation of the process of reflection of laser beams from rough surfaces with different degrees of roughness. Based on the results of numerical experiments the applicability of the method of correlation analysis of speckle-structures for non-destructive inspection of surfaces with different parameters of roughness was evaluated. The optimal ratios between the parameters of the rough surfaces and parameters of the optical system, which provide the best efficiency of the method, were determined. It was established that in case of the increase of the number of topological charges the sensitivity of the optical system to changes of parameters of surface roughness increases.

Gorjunov, A. E.; Pavlov, P. V.; Petrov, N. V.

2014-09-01

254

Formulation and Evaluation of a Protein-loaded Solid Dispersions by Non-destructive Methods  

Microsoft Academic Search

The purpose of this investigation was to develop solid dispersion (SD) formulation of cyclosporine (CyA) using polyethylene\\u000a glycol (PEG-6000) to enhance its dissolution rate followed by nondestructive method for the prediction of both drug and carrier.\\u000a SD formulations were prepared by varying the ratio of CyA and PEG-6000 by solvent evaporation technique and characterized\\u000a by dissolution, scanning electron microscopy (SEM),

Ziyaur Rahman; Ahmed S. Zidan; Mansoor A. Khan

2010-01-01

255

Development of advanced SQUID system for nondestructive evaluation of material degradation in power plants  

SciTech Connect

A newer and more advanced version of the SQUID sensor system for estimating the degradation of materials in power plants have been developed. The miniaturized SQUID sensor developed for nondestructive measurement is 262 mm high, 152 mm in diameter, and 5 kg in weight, making it only one-twelfth the size and one-tenth the weight of a conventional SQUID sensor. Tests have demonstrated that the new SQUID sensor can successfully estimate fatigue damage in Type 316 stainless steel.

Otaka, M.; Hayashi, E. [Hitachi, Ltd., Ibaraki (Japan)

1995-08-01

256

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

NASA Technical Reports Server (NTRS)

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.

Waller, Jess M.; Saulsberry, Regor L.

2012-01-01

257

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

SciTech Connect

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

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

2013-01-01

258

Quantitative evaluation of color image segmentation results  

Microsoft Academic Search

In this paper we consider the problem of the automatic evaluation of the results of color image segmentation. Liu and Yang (1994) have proposed an evaluation function, inspired by the qualitative criteria for good image segmentation established by Haralick and Shapiro (1985), that does not require that the user set any parameter or threshold value. We identify some limitations in

M. Borsotti; Paola Campadelli; Raimondo Schettini

1998-01-01

259

Visualizing Industrial CT Volume Data for Nondestructive Testing Applications  

E-print Network

Visualizing Industrial CT Volume Data for Nondestructive Testing Applications Runzhen Huang Kwan for the visualization of high-resolution volume data generated from industrial computed tomography for nondestructive, interac- tive visualization, nondestructive testing and evaluation, sci- entific visualization, surface

Ma, Kwan-Liu

260

Quantitative Evaluation of Management Courses: Part 1  

ERIC Educational Resources Information Center

The author describes how he developed a method of evaluating and comparing management courses of different types and lengths by applying an ordinal system of relative values using a process of transmutation. (MS)

Cunningham, Cyril

1973-01-01

261

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

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

262

Nondestructive Evaluation of Foam Insulation on the Space Shuttle External Tank  

NASA Technical Reports Server (NTRS)

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.

Richter, Joel; Walker, James L.

2006-01-01

263

Application of Advanced Nondestructive Evaluation Techniques for Cylindrical Composite Test Samples  

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

264

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

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

265

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

NASA Astrophysics Data System (ADS)

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

Ando, Masatoshi; Sharp, Nathan; Adams, Douglas

2012-04-01

266

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

NASA Technical Reports Server (NTRS)

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

Miller, James G.

1987-01-01

267

Applications of pulse heating thermography and lock-in thermography to quantitative nondestructive evaluations  

Microsoft Academic Search

This paper describes several experimental investigations of newly developed thermographic NDT techniques based on the transient temperature measurements. Several experimental results of the pulse heating thermographic NDT and the lock-in thermographic NDT are shown.

Takahide Sakagami; Shiro Kubo

2002-01-01

268

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

NASA Astrophysics Data System (ADS)

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.

Hellen, Adam; Mandelis, Andreas; Finer, Yoav; Amaechi, Bennett T.

2011-03-01

269

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

SciTech Connect

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

Day, R.A.

1988-12-31

270

Evaluation (not validation) of quantitative models.  

PubMed Central

The present regulatory climate has led to increasing demands for scientists to attest to the predictive reliability of numerical simulation models used to help set public policy, a process frequently referred to as model validation. But while model validation may reveal useful information, this paper argues that it is not possible to demonstrate the predictive reliability of any model of a complex natural system in advance of its actual use. All models embed uncertainties, and these uncertainties can and frequently do undermine predictive reliability. In the case of lead in the environment, we may categorize model uncertainties as theoretical, empirical, parametrical, and temporal. Theoretical uncertainties are aspects of the system that are not fully understood, such as the biokinetic pathways of lead metabolism. Empirical uncertainties are aspects of the system that are difficult (or impossible) to measure, such as actual lead ingestion by an individual child. Parametrical uncertainties arise when complexities in the system are simplified to provide manageable model input, such as representing longitudinal lead exposure by cross-sectional measurements. Temporal uncertainties arise from the assumption that systems are stable in time. A model may also be conceptually flawed. The Ptolemaic system of astronomy is a historical example of a model that was empirically adequate but based on a wrong conceptualization. Yet had it been computerized--and had the word then existed--its users would have had every right to call it validated. Thus, rather than talking about strategies for validation, we should be talking about means of evaluation. That is not to say that language alone will solve our problems or that the problems of model evaluation are primarily linguistic. The uncertainties inherent in large, complex models will not go away simply because we change the way we talk about them. But this is precisely the point: calling a model validated does not make it valid. Modelers and policymakers must continue to work toward finding effective ways to evaluate and judge the quality of their models, and to develop appropriate terminology to communicate these judgments to the public whose health and safety may be at stake. PMID:9860904

Oreskes, N

1998-01-01

271

Evaluation (not validation) of quantitative models.  

PubMed

The present regulatory climate has led to increasing demands for scientists to attest to the predictive reliability of numerical simulation models used to help set public policy, a process frequently referred to as model validation. But while model validation may reveal useful information, this paper argues that it is not possible to demonstrate the predictive reliability of any model of a complex natural system in advance of its actual use. All models embed uncertainties, and these uncertainties can and frequently do undermine predictive reliability. In the case of lead in the environment, we may categorize model uncertainties as theoretical, empirical, parametrical, and temporal. Theoretical uncertainties are aspects of the system that are not fully understood, such as the biokinetic pathways of lead metabolism. Empirical uncertainties are aspects of the system that are difficult (or impossible) to measure, such as actual lead ingestion by an individual child. Parametrical uncertainties arise when complexities in the system are simplified to provide manageable model input, such as representing longitudinal lead exposure by cross-sectional measurements. Temporal uncertainties arise from the assumption that systems are stable in time. A model may also be conceptually flawed. The Ptolemaic system of astronomy is a historical example of a model that was empirically adequate but based on a wrong conceptualization. Yet had it been computerized--and had the word then existed--its users would have had every right to call it validated. Thus, rather than talking about strategies for validation, we should be talking about means of evaluation. That is not to say that language alone will solve our problems or that the problems of model evaluation are primarily linguistic. The uncertainties inherent in large, complex models will not go away simply because we change the way we talk about them. But this is precisely the point: calling a model validated does not make it valid. Modelers and policymakers must continue to work toward finding effective ways to evaluate and judge the quality of their models, and to develop appropriate terminology to communicate these judgments to the public whose health and safety may be at stake. PMID:9860904

Oreskes, N

1998-12-01

272

A Quantitative Evaluation of Dissolved Oxygen Instrumentation  

NASA Technical Reports Server (NTRS)

The implications of the presence of dissolved oxygen in water are discussed in terms of its deleterious or beneficial effects, depending on the functional consequences to those affected, e.g., the industrialist, the oceanographer, and the ecologist. The paper is devoted primarily to an examination of the performance of five commercially available dissolved oxygen meters. The design of each is briefly reviewed and ease or difficulty of use in the field described. Specifically, the evaluation program treated a number of parameters and user considerations including an initial check and trial calibration for each instrument and a discussion of the measurement methodology employed. Detailed test results are given relating to the effects of primary power variation, water-flow sensitivity, response time, relative accuracy of dissolved-oxygen readout, temperature accuracy (for those instruments which included this feature), error and repeatability, stability, pressure and other environmental effects, and test results obtained in the field. Overall instrument performance is summarized comparatively by chart.

Pijanowski, Barbara S.

1971-01-01

273

Test and Evaluation of the Magnograph (TM) unit, a nondestructive wire rope tester  

NASA Astrophysics Data System (ADS)

The nondestructive wire rope test device, a unitized AC/DC Magnograph, was tested for operational characteristics prior to acquisition by Naval field activities and start of inspection programs. The Magnograph was tested for loss of metallic area (LMA) and local fault (LF) detection accuracy. Wire ropes 1/2, 3/4, 1-1/8, 1-1/2, 2, and 2-1/2 inches in diameter were tested on a wire rope test track to find the accuracy of the unit. Two mining wire ropes, guy wires of a 1,000-ft-tall tower, and wire rope for 400-, 250-, and 30-ton cranes were used to determine operational characteristics of the Magnograph.

Underbakke, L. D.; Haynes, H. H.

1982-07-01

274

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

NASA Astrophysics Data System (ADS)

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.

Martinho, E.; Dionísio, A.

2014-10-01

275

Rapid, non-destructive evaluation of ultrathin WSe{sub 2} using spectroscopic ellipsometry  

SciTech Connect

The utilization of tungsten diselenide (WSe{sub 2}) in electronic and optoelectronic devices depends on the ability to understand and control the process-property relationship during synthesis. We demonstrate that spectroscopic ellipsometry is an excellent technique for accurate, non-destructive determination of ultra-thin (<30 nm) WSe{sub 2} properties. The refractive index (n) and extinction coefficient (k) were found to be independent of thickness down to 1.3 nm, and were used to determine film thickness, which was confirmed to be within 9% of values found via atomic force microscopy. Finally, the optical bandgap was found to closely correlate with thickness, ranging from 1.2 to 1.55 eV as the WSe{sub 2} is thinned to the equivalent of 2 atomic layers.

Eichfeld, Sarah M.; Lin, Yu-Chuan; Hossain, Lorraine [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Eichfeld, Chad M. [Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Robinson, Joshua A., E-mail: jrobinson@psu.edu [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

2014-09-01

276

Nondestructive Evaluation of Plane Crack Tip in a Thin Plate Using Laser-Induced Pulse Wave and Symmetric Lamb Wave  

NASA Astrophysics Data System (ADS)

A new measurement system for detecting microcrack tips was investigated for the nondestructive evaluation of thin plates. In this system, we combined two different techniques. One technique is the use of a low-power pulsed laser to induce ultrasonic pulse waves, which are generated by the thermoelastic effect. The other technique is the vibration of samples using a symmetric mode Lamb wave at low frequencies, which causes the fluctuation of crack tips. Taking account of the Lamb wave propagation in the plate sample, laser-induced waves were excited to pass through plane cracks under two different fluctuation conditions (compression and extension). The characteristic difference between the frequency spectra of these waves gave us information on fluctuating cracks. Using an acrylic sample, we confirmed that the difference in phase could be used for the detection of crack tips.

Nakase, Ryosuke; Nakata, Kazuki; Matsukawa, Mami

2012-07-01

277

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

E-print Network

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 ...

American Society for Testing and Materials. Philadelphia

2010-01-01

278

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

E-print Network

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...

American Society for Testing and Materials. Philadelphia

2010-01-01

279

High temperature ultrasonic transducers for the generation of guided waves for non-destructive evaluation of pipes  

SciTech Connect

Applications for non-destructive evaluation and structural health monitoring of steam generators require ultrasonic transducers capable of withstanding the high temperatures of the pipes and heat exchangers. These applications require a strong coupling of the transducer to the heat exchanger’s complex geometry at the elevated temperatures. Our objective is to use spray-on piezo-electrics for depositing comb transducers onto the curved surfaces. This paper shows results for composite transducers such as lead zirconate titanate/ bismuth titanate and bismuth titanate/ lithium niobate. The comb transducers were prepared by precision laser ablation. The feasibility of producing second harmonic waves in rods with these spay-on comb transducers was demonstrated and paves the way toward measuring material degradation early-on before crack initiation occurs.

Sinding, K.; Searfass, C.; Malarich, N.; Reinhardt, B.; Tittmann, B. R. [Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802 (United States)

2014-02-18

280

Nondestructive Evaluation of the Gimbal Joint Flowliner Slots in the Space Shuttle Main Propulsion System Hydrogen Feedline  

NASA Technical Reports Server (NTRS)

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.

Suits, Michael W.; Bryson, Craig C.

2006-01-01

281

Nondestructive evaluation of acoustic properties of fuel cell proton-exchange membranes by vector contrast acoustic microscopy  

NASA Astrophysics Data System (ADS)

In recent years, the interest in the research and development of "green energy" has increased dramatically, with numerous research grants and investment in the areas of wind power, solar power and fuel cell technology. We present results obtained from the evaluation of the acoustic properties of proton-exchange membranes used in hydrogen fuel cells, which relate directly to the microelastic properties of such membranes. These properties play an important role in the durability and applicability as well as the efficiency of such membranes. DuPont Nafion membranes are the most commonly used polymeric membranes in hydrogen/oxygen fuel cells and are therefore used as examples in this study. The microscope used in this non-destructive characterization study is a vector-contrast version of the scanning acoustic microscope which yields images in magnitude- and phase contrast.

Kamanyi, Albert E.; Grill, Wolfgang

2012-04-01

282

Evaluating the Nuclear Peace HypothesisA Quantitative Approach  

Microsoft Academic Search

Do nuclear weapons reduce the probability of war? This article quantitatively evaluates the nuclear peace hypothesis. The results indicate that the impact of nuclear weapons is more complicated than is conventionally appreciated. Both proliferation optimists and pessimists find confirmation of some of their key claims. When a nuclear asymmetry exists between two states, there is a greater chance of militarized

Robert Rauchhaus

2009-01-01

283

QUANTITATIVE EVALUATION OF FEATURE SETS, SEGMENTATION ALGORITHMS AND COLOR  

E-print Network

QUANTITATIVE EVALUATION OF FEATURE SETS, SEGMENTATION ALGORITHMS AND COLOR CONSTANCY ALGORITHMS throughout and made me complete things on time. It were his words that taught me the essence of research. As told by him once, "Research may be sometimes disappointing but the results out of it are rewarding

Barnard, Kobus

284

A Framework for the Quantitative Evaluation of Voting Rules  

E-print Network

A Framework for the Quantitative Evaluation of Voting Rules Michael Munie Computer Science to characterize the set of desirable social choice functions, researchers have proposed axioms that all social of social choice functions that builds from and provides a unifying framework for previ- ous research

Shoham, Yoav

285

Power information systems security: modeling and quantitative evaluation  

Microsoft Academic Search

This paper presents a modeling language and a quantitative evaluation approach for the security of power information systems. We firstly design a security architecture design trace language to universally describe system structures, services, security policies, attack behaviors and countermeasures. Next an automated risk analysis algorithm is proposed to get attack traces of power information systems. Then, based on the concept

Yan Hu; Xiaorong Xie; Yaozhong Xin

2004-01-01

286

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

Microsoft Academic Search

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

I. E. Abdou; W. K. Pratt

1979-01-01

287

The falling weight deflectometer (FWD) test is one of the most com-monly used tools for nondestructive evaluation of flexible pavements.  

E-print Network

for nondestructive evaluation of flexible pavements. Although the test is intrinsically dynamic, the state that the fore- going discrepancy may lead to systematic errors in the estimation of pavement moduli and extract the static pavement response from transient FWD records. With the filtered (i.e., zero

Guzina, Bojan

288

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

PubMed

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

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

2014-01-01

289

Quantitative evaluation of axial wall taper in prepared artificial teeth.  

PubMed

The purpose of this study was to quantitatively evaluate the axial wall taper of prepared artificial teeth using a non-contact three-dimensional shape measuring system. A total of 54 artificial teeth prepared by pre-clinical dental students for complete cast restorations were evaluated. For quantitative analysis, five cross sections were computer-graphically placed perpendicularly to the z-axis. The surface coordinate values (x, y, z) of each cross section were converted into polar coordinate values (r, theta), which were then graphically rendered to a two-dimensional plane. At four points, each 90 degrees from the distal center point of the cross section, the axial wall taper was quantitatively calculated using a formula based on the differences in radius between the highest and lowest positions of the cross sections of the prepared tooth. The average calculated taper was 5.8 degrees in the distal region, 21.7 degrees in the buccal region, 14.9 degrees in the mesial region and 12.5 degrees in the lingual region. These results suggest that the axial wall taper of prepared teeth can be quantitatively evaluated using this measuring system. PMID:16313090

Okuyama, Yayoi; Kasahara, Shin; Kimura, Kohei

2005-09-01

290

Large area detector based computed tomography system for production nondestructive evaluation.  

SciTech Connect

We present a system for industrial x-ray computed tomography that has been optimized for all phases of nondestructive component inspection. Data acquisition is greatly enhanced by the use of high resolution, large area, flat-panel amorphous-silicon detectors. The detectors have proven, over several years, to be a robust alternative to CCD-optics and image intensifier CT systems. In addition to robustness, these detectors provide the advantage of area detection as compared with the single slice geometry of linear array systems. Parallel processing provides significant speed improvements for data reconstruction, and is implemented for parallel-beam, fan-beam and Feldkamp conebeam reconstruction algorithms. By clustering ten or more equal-speed computers, reconstruction times are reduced by an order of magnitude. We have also developed interactive software for visualization and interrogation of the full three-dimensional dataset. Inspection examples presented in this paper include an electro-mechanical device, nonliving biological specimens and a turbo-machinery component. We also present examples of everyday items for the benefit of the layperson.

Keating, S. C. (Scott C.); Davis, A. A. (Anthony A.); Claytor, T. N. (Thomas N.)

2001-01-01

291

Nondestructive thermoelectric evaluation of the grit blasting induced effects in metallic biomaterials  

NASA Astrophysics Data System (ADS)

Grit blasting is a surface treatment process widely used to enhance mechanical fixation of the implants through increasing their roughness. Test samples of two metallic biomaterial alloys such 316LVM and Ti6Al4V were blasted by projecting Al2O3 and ZrO2 particles which yield a coarse and a fine rough surface. Then, the blasted samples were thermally treated before and after partial stress relaxation and measured by non-destructive thermoelectric techniques (NDTT), the non-contacting and contacting thermoelectric power (TEP) measurements respectively. It has been found that the TEP measurements are associated directly with the subtle material variations such as cold work and compressive residual stresses due to plastic deformation produced by grit blasting. The TEP measurements clearly demonstrate that the non-contact NDTT technique is very sensitive to the reverse transformation of the ?'-martensite (blasted 316LVM) and the expected relaxation of compressive residual stresses with increasing the severity of the thermal treatment (blasted 316LVM and Ti-6Al-4V), while the contact NDTT results are closely related to grain size refinement and work hardening.

Carreon, H.; Ruiz, A.; Barriuso, S.; González-Carrasco, J. L.; Caballero, F. G.; Lieblich, M.

2013-01-01

292

Shearographic and thermographic nondestructive evaluation of the space shuttle structure and thermal protection systems (TPS)  

NASA Astrophysics Data System (ADS)

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.

Davis, Christopher K.

1996-11-01

293

Non-Destructive Evaluation of Rock Bolts Associated With Optical Strain Sensors at the Homestake Gold Mine  

NASA Astrophysics Data System (ADS)

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.

Kogle, M. M.; Fratta, D.; Wang, H. F.; Geox^Tm

2010-12-01

294

Analysis of a concentric coplanar capacitive sensor for nondestructive evaluation of multi-layered dielectric structures  

Microsoft Academic Search

A concentric coplanar capacitive sensor is analyzed for the quantitative characterization of material properties for multi-layered dielectrics. The sensor output signal, transcapacitance CT, is related to the thickness and dielectric constant of each layer of the material under test. Electrostatic Green¿s functions due to point charges over different dielectric structures are derived utilizing the Hankel transform given the cylindrical symmetry

Tianming Chen; Nicola Bowler

2010-01-01

295

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

Microsoft Academic Search

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

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

296

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

SciTech Connect

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.

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

297

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

NASA Astrophysics Data System (ADS)

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.

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

1994-09-01

298

Open-ended sensors for microwave nondestructive evaluation of layered composite media. Ph.D. Thesis  

SciTech Connect

The need to monitor the composition, integrity, and maintenance of materials, structures and equipments gave rise to the development of the field of NonDestructive Testing and Examination (NDT & E). With the prevalent use of metals due to their strength, early NDT techniques were established to deal mostly with metallic media. The advent of new lightweight and exceptionally strong dielectric composite materials, replacing metals in many applications, has diversified the field of NDT & E tremendously. The low conductivity associated with these dielectric materials such as plastics, ceramics and carbon fiber composites has rendered many traditional and conventional NDT techniques ineffective. The ability of microwaves to penetrate inside dielectric media and their sensitivity to minute structural and dimensional variations within the medium, coupled with availability of large bandwidths are of great significance. Microwave techniques have reemerged recently not only to fill many gaps left vacant by traditional NDT & E techniques, but also to further expose new alleys in this expanding and demanding field. Near-field interaction of electromagnetic waves with different material media is a complex process. Without a thorough understanding of the nature of reflection, attenuation and scattering mechanisms involved, even the most careful measurements may render themselves useless. The objective of this work is to take a forward step toward filling some of the existing gaps for concise theoretical formulations and practical implementation in application to microwave NDT & E of layered dielectric composite media. Models pertaining to analysis of electromagnetic radiation into layered, generally lossy dielectric composite media from two prevalent sensors, namely, an open-ended rectangular waveguide and an open-ended coaxial line are introduced.

Bakhtiari, S.

1992-12-31

299

Quantitative non-destructive testing  

NASA Technical Reports Server (NTRS)

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.

Welch, C. S.

1985-01-01

300

A Fast Molecular Nondestructive Protocol for Evaluating Aerobic Bacterial Load on Fresh-Cut Lettuce  

Microsoft Academic Search

Elaboration of minimally processed or fresh-cut vegetables requires a quick and reliable method for detection of bacterial contamination over the recommended limits. PCR-based methods fulfil these requirements, but amplification from DNA preparations of the food product is often hampered due to inhibiting substances. The purpose of this study was to develop a fast quantitative PCR (qPCR)-based method for aerobic bacterial

P. Gómez; M. Pagnon; M. Egea-Cortines; F. Artés; J. Weiss

2010-01-01

301

Reference Specimen for Nondestructive Evaluation: Characterization of the Oxide Layer of a Cold Shot in Inconel 600  

NASA Astrophysics Data System (ADS)

The presence of a cold shot in an aircraft turbine blade can lead to the catastrophic failure of the blade and ultimately to the failure of the power plant. Currently, no nondestructive evaluation (NDE) method exists to detect this kind of defect. This deficiency is primarily due to the fact that the only known cold shot defects in existence are those found in failed blades. Therefore, in order to develop effective NDE methods, reference specimens are needed which mimic the embedded oxide layer that is a primary distinguishing feature of a cold shot. Here, we present a procedure to synthetically reproduce the features of a real cold shot in Inconel 600 and the precise characterization of this oxide layer as a reference specimen suitable for NDE evaluation. As a first step to develop a suitable NDE technique, high-frequency ultrasound simulations are considered. A theoretical 1-D model is developed in order to quantify the multiple reflection-transmission trajectory of the acoustic wave in the reference specimen. This paper also presents an experimental determination of the density and the Young's modulus of the Inconel 600 oxide, which are required as inputs to calculate the acoustic impedance used in the theoretical model.

Saletes, I.; Filleter, T.; Goldbaum, D.; Chromik, R. R.; Sinclair, A. N.

2014-12-01

302

A Quantitative Method To Evaluate Neutralizer Toxicity againstAcanthamoeba castellanii  

Microsoft Academic Search

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 againstA. castellanii. Two methods were evaluated. A quantitative microtiter method for enumerating A. castellaniiwas evaluated by a 50% lethal dose endpoint method. The microtiter method was compared with the hemacytometer count

SALLY L. BUCK; ANDRUTH A. ROSENTHAL

1996-01-01

303

Development of nondestructive evaluation methods and prediction of effects of flaws on the fracture behavior of structural ceramics  

SciTech Connect

Continuous fiber ceramic matrix composites are being developed for turbine engine components, heat exchangers, and hot-gas filters in fossil energy systems. Reliable application requires nondestructive evaluation (NDE) methods that provide data for quality assurance and inputs to life time prediction models and that aid in process development. NDE developments at Argonne have focused on methods to assess density distribution, fiber orientation (for mechanical properties), and defect detection in both SiC/SiC and A1{sub 2}O{sub 3}/A1{sub 2}O{sub 3} materials. and that also assess the chemical state at fiber/matrix interfaces. 2-D cloth lay-up and 3-D weave CVI-infiltrated SiC/SiC specimens were studied by X-ray imaging methods now under development. Microfocus X-ray computerized tomography (MXCT) methods are being developed to provide these data. Multinuclear Nuclear Magnetic Resonance spectroscopy (13C, 29Si, and 11B) is under development for quantizing B content at fiber/matrix interfaces. Magic angle spinning techniques on SiC/SiC specimens with different coating thicknesses showed that quantification of B at the Interface is achievable. NDE data are being coupled to room- and elevated-temperature fracture studies to evaluate effects of fiber orientation and fiber coating thickness on resulting flaw morphology and mechanical properties of Nicalon-fiber-reinforced SiC matrix composites. Specifically, composites with fiber cloth lay-up sequences of varying coating thicknesses were evaluated. For room-temperature mechanical evaluation, composites with carbon-fiber coating thicknesses of 0 and 0.2 {mu}m were used, while elevated-temperature studies used composites with a coating thickness of 0.4 {mu}m. Composites with uncoated fibers failed in a brittle mode, while composites with 0.2 {mu}m fiber coating showed noncatastrophic failure.

Ellingson, W.A.; Singh, J.P.; Sivers, E.A. [and others

1995-04-01

304

Quantitative evaluation of gain and losses in quaternary lasers  

SciTech Connect

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.

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

1985-06-01

305

Study on Non-destructive Evaluation of Flaws in Multilayer Duct Using an HTS-SQUID Gradiometer  

NASA Astrophysics Data System (ADS)

We have investigated the performance of an eddy-current non-destructive evaluation (NDE) system using an HTS Superconducting quantum interference device (SQUID) gradiometer with the aim of applying it to the equipment in power plants. Use of the SQUID-NDE technique has an advantage, because SQUID has a high sensitivity or low noise characteristics at low frequencies for detecting magnetic signals. In the present research, we have tried to detect flaws in test samples simulating a multilayer duct in a plant, which consists of multilayer aluminum and resin plates. In the test samples, resin plates were sandwiched by aluminum plates. The top aluminum plate and the bottom multilayer aluminum plates were assumed as outer and inner duct layers, and the resin plates were assumed as an insulation layer in a multilayer duct of the plant. A slit-shaped through hole was opened in the bottom layer, and was assumed as a flaw in the duct layer. By using a SQUID-ECT system, we could detect signals from flaws located at more than 10 mm deep positions in the test samples.

Kawano, J.; Ogawa, A.; Ishikawa, F.; Tanabe, K.

306

Non-destructive evaluation of nano-sized structure of thin film devices by using small angle neutron scattering.  

PubMed

Nano-sized multi-layers copper-doped SrZrO3, platinum (Pt) and silicon oxide (SiO2) on silicon substrates were prepared by dense plasma focus (DPF) device with the high purity copper anode tip and analyzed by using small angle neutron scattering (SANS) to establish a reliable method for the non-destructive evaluation of the under-layer structure. Thin film was well formed at the time-to-dip of 5 microsec with stable plasma of DPF. Several smooth intensity peaks were periodically observed when neutron beam penetrates the thin film with multi-layers perpendicularly. The platinum layer is dominant to intensity peaks, where the copper-doped SrZnO3 layer next to the platinum layer causes peak broadening. The silicon oxide layer has less effect on the SANS spectra due to its relative thick thickness. The SANS spectra shows thicknesses of platinum and copper-doped SrZnO3 layers as 53 and 25 nm, respectively, which are well agreement with microstructure observation. PMID:21446565

Shin, E J; Seong, B S; Choi, Y; Lee, J K

2011-01-01

307

Ultrasonic Imaging Technology Helps American Manufacturer of Nondestructive Evaluation Equipment Become More Competitive in the Global Market  

NASA Technical Reports Server (NTRS)

Sonix, Inc., of Springfield, Virginia, has implemented ultrasonic imaging methods developed at the NASA Lewis Research Center. These methods have heretofore been unavailable on commercial ultrasonic imaging systems and provide significantly more sensitive material characterization than conventional high-resolution ultrasonic c-scanning. The technology transfer is being implemented under a cooperative agreement between NASA and Sonix, and several invention disclosures have been submitted by Dr. Roth to protect Lewis interests. Sonix has developed ultrasonic imaging systems used worldwide for microelectronics, materials research, and commercial nondestructive evaluation (NDE). In 1993, Sonix won the U.S. Department of Commerce "Excellence in Exporting" award. Lewis chose to work with Sonix for two main reasons: (1) Sonix is an innovative leader in ultrasonic imaging systems, and (2) Sonix was willing to apply the improvements we developed with our in-house Sonix equipment. This symbiotic joint effort has produced mutual benefits. Sonix recognized the market potential of our new and highly sensitive methods for ultrasonic assessment of material quality. We, in turn, see the cooperative effort as an effective means for transferring our technology while helping to improve the product of a domestic firm.

1995-01-01

308

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

SciTech Connect

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.

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

309

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

SciTech Connect

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.

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

310

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

SciTech Connect

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.

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

1998-12-31

311

An effective 3-D finite element scheme for computing electromagnetic field distortions due to defects in eddy-current nondestructive evaluation  

Microsoft Academic Search

A new three-dimensional (3-D) finite element scheme for eddy-current nondestructive evaluation (NDE) problems is described that calculates directly the perturbation of the electromagnetic field due to defects in metallic specimens. The computational costs of such problems are usually very high using available finite element schemes, and the new scheme is supposed to lower these costs. The basic concept, the direct

Zsolt Badics; Yoshihiro Matsumoto; Kazuhiko Aoki; Fumio Nakayasu; Mitsuru Uesaka; Kenzo Miya

1997-01-01

312

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...

313

Time Domain Terahertz Non-Destructive Evaluation of Aeroturbine Blade Thermal Barrier Coatings  

NASA Astrophysics Data System (ADS)

Time domain terahertz (TD-THz) non destructive evaluation (NDE) imaging is used to two-dimensionally map the thickness of yttria stabilized zirconia (YSZ) thermal barrier coatings (TBC) on aircraft engine turbine blades. Indications of thermal degradation can be seen. The method is non-contact, rapid, and requires no special preparation of the blade.

White, Jeffrey; Fichter, G.; Chernovsky, A.; Whitaker, John F.; Das, D.; Pollock, Tresa M.; Zimdars, David

2009-03-01

314

Development and applications of nondestructive evaluation at Marshall Space Flight Center  

NASA Technical Reports Server (NTRS)

A brief description of facility design and equipment, facility usage, and typical investigations are presented for the following: Surface Inspection Facility; Advanced Computer Tomography Inspection Station (ACTIS); NDE Data Evaluation Facility; Thermographic Test Development Facility; Radiographic Test Facility; Realtime Radiographic Test Facility; Eddy Current Research Facility; Acoustic Emission Monitoring System; Advanced Ultrasonic Test Station (AUTS); Ultrasonic Test Facility; and Computer Controlled Scanning (CONSCAN) System.

Whitaker, Ann F.

1990-01-01

315

Relationship between non-destructive OCT evaluation of resins composites and bond strength in a cavity  

NASA Astrophysics Data System (ADS)

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.

Bakhsh, T. A.; Sadr, A.; Shimada, Y.; Khunkar, S.; Tagami, J.; Sumi, Y.

2012-01-01

316

A fast molecular nondestructive protocol for evaluating aerobic bacterial load on fresh-cut lettuce.  

PubMed

Elaboration of minimally processed or fresh-cut vegetables requires a quick and reliable method for detection of bacterial contamination over the recommended limits. PCR-based methods fulfil these requirements, but amplification from DNA preparations of the food product is often hampered due to inhibiting substances. The purpose of this study was to develop a fast quantitative PCR (qPCR)-based method for aerobic bacterial enumeration in fresh-cut lettuce, using as reference the centrifugation water (CW) that comes up during processing instead of the food matrix itself. Comparisons between bacterial numbers on lettuce leaves before processing and bacterial numbers in the CW both for naturally occurring bacterial populations and for artificially inoculated lettuce were performed. On an average, 35% of the natural bacterial population and 64% of inoculated bacteria were recovered in the CW. Bacterial number in CW was proportional to initial lettuce contamination suggesting that measures on CW allow a narrow estimation of lettuce contamination. In qPCR, a 23S rDNA region was amplified from bacterial DNA present in the CW, followed by melting peak analyses and quantification. Enumeration of cell number by qPCR did not differ significantly from plate assay and might therefore replace it. The proposed protocol, which includes sample taking, DNA extraction and qPCR from the CW can be performed within less than 5 h. The resulting quantification might be used as a proxy of initial lettuce contamination, allowing direct intervention measures before fresh-cut commodity is shipped from the factory. PMID:21339159

Gómez, P; Pagnon, M; Egea-Cortines, M; Artés, F; Weiss, J

2010-10-01

317

Monitoring of Reinforced Concrete Corrosion and Deterioration by Periodic Multi-Sensor Non-Destructive Evaluation  

NASA Astrophysics Data System (ADS)

The paper showcases a collaborative benchmark project evaluating NDE methods for deterioration monitoring of laboratory bridge decks. The focus of this effort is to design and build concrete test specimens, artificially induce and monitor corrosion, periodically perform multi-sensor NDE inspections, followed by 3D imaging and destructive validations. NDE methods used include ultrasonic echo array, ground penetrating radar (GPR), active infrared thermography with induction heating, and time-resolved thermography with induction heating.

Arndt, R. W.; Cui, J.; Huston, D. R.

2011-06-01

318

Nondestructive evaluation of loose assemblies using multi-frequency eddy currents and artificial neural networks  

NASA Astrophysics Data System (ADS)

This paper considers the problem of the evaluation of metallic assemblies in an aeronautical context, by means of a non-invasive method. The problems lies in the estimation of the distance separating two aluminum plates representative of a loose assembly (up to 300 µm), the top plate being possibly of unknown thickness ranging from 1 to 8 mm. To do so, the eddy current (EC) method is chosen, because it allows non-contact evaluation of conducting media to be carried out, which is sensitive to electrical conductivity changes in the part under evaluation, and hence to the presence of an air gap between parts. The problem falls into the category of evaluation of a multilayered conductive structure starting from EC data, which is an ill-posed problem. In order to bypass these difficulties, as well as to deal with the uncertainties that may be introduced by the experimental set-up, a ‘non-model’ approach is implemented by means of an artificial neural network (ANN). The latter is elaborated in a statistical learning approach starting from the experimental EC data provided by a ferrite cored coil EC probe used to investigate an assembly mockup of adjustable configuration. Moreover, in order to build a learning database allowing a robust and accurate ANN to be elaborated, as well as to deal with assemblies of unknown thicknesses, we consider EC data obtained at different frequencies chosen in an adjusted frequency bandwidth, experimentally determined so as to optimize the sensitivity toward the presence of an air gap between parts. The implementation of the proposed approach for distances between parts ranging from 60 to 300 µm provided estimated root mean square errors ranging from 7 ?m up to 50 µm for the estimation of the distance between parts, and ranging from 20 µm up to 1.4 mm for the estimation of the top plates, ranging from 1 to 8 mm, respectively.

Vourc'h, Eric; Joubert, Pierre-Yves; Le Gac, Guillaume; larzabal, Pascal

2013-12-01

319

Nondestructive evaluation/characterization of composite materials and structures using the acousto-ultrasonic techniques  

NASA Technical Reports Server (NTRS)

This paper introduces the nature and the underlying rational of the acousto-ultrasonic stress wave factor technique and some of its applications to composite materials and structures. Furthermore, two examples of successful application of the acousto-ultrasonic technique are presented in detail. In the first example, the acousto-ultrasonic technique is used to evaluate the adhesive bond strength between rubber layers and steel plates, and in the seocnd example the tehcnique is used to monitor progressive damage in wire rope.

Dos Reis, H. L. M.; Vary, A.

1988-01-01

320

Image correlation nondestructive evaluation of impact damage in a glass fiber composite  

NASA Technical Reports Server (NTRS)

Presented in viewgraph format, digital image correlation, damage in fibrous composites, and damaged coupons (cross-ply scotchply GI-Ep laminate) are outlined. It was concluded that the image correlation accuracy was 0.03 percent; strains can be processed through Tsai-Hill failure criteria to qualify the damage; the statistical data base must be generated to evaluate certainty of the damage estimate; size effects need consideration; and better numerical techniques are needed.

Russell, Samuel S.

1990-01-01

321

Eddy current technique applied to the nondestructive evaluation of turbine blade wall thickness  

NASA Astrophysics Data System (ADS)

The high pressure turbine blades of jet engines show internal channels designed for air cooling. These recesses define the internal walls (partitions) and external walls of the blade. The external wall thickness is a critical parameter which has to be systematically checked in order to ensure the blade strength. The thickness evaluation is usually lead by ultrasonic technique or by X-ray tomography. Nevertheless, both techniques present some drawbacks related to measurement speed and automation capability. These drawbacks are bypassed by the eddy current (EC) technique, well known for its robustness and reliability. However, the wall thickness evaluation is made difficult because of the complexity of the blade geometry. In particular, some disturbances appear in the thickness evaluation because of the partitions, which exclude the use of classical EC probes such as cup-core probe. In this paper, we show the main advantages of probes creating an uniformly oriented magnetic field in order to reduce the partition disturbances. Furthermore, we propose a measurement process allowing to separate the wall thickness parameter from the EC signals. Finally, we present some experimental results validating the proposed technique.

Le Bihan, Yann; Joubert, Pierre-Yves; Placko, Dominique

2000-05-01

322

Simulation evaluation of quantitative myocardial perfusion assessment from cardiac CT  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

323

Portable microwave instrument for non-destructive evaluation of structural characteristics  

DOEpatents

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.

Bible, Don W. (Clinton, TN); Crutcher, Richard I. (Knoxville, TN); Sohns, Carl W. (Oak Ridge, TN); Maddox, Stephen R. (Loudon, TN)

1995-01-01

324

Portable microwave instrument for non-destructive evaluation of structural characteristics  

DOEpatents

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.

Bible, D.W.; Crutcher, R.I.; Sohns, C.W.; Maddox, S.R.

1995-01-24

325

Nondestructive equipment study  

NASA Technical Reports Server (NTRS)

Identification of existing nondestructive Evaluation (NDE) methods that could be used in a low Earth orbit environment; evaluation of each method with respect to the set of criteria called out in the statement of work; selection of the most promising NDE methods for further evaluation; use of selected NDE methods to test samples of pressure vessel materials in a vacuum; pressure testing of a complex monolythic pressure vessel with known flaws using acoustic emissions in a vacuum; and recommendations for further studies based on analysis and testing are covered.

1985-01-01

326

An anthropomorphic phantom for quantitative evaluation of breast MRI  

PubMed Central

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

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

327

Prior image constrained compressed sensing: a quantitative performance evaluation  

NASA Astrophysics Data System (ADS)

The appeal of compressed sensing (CS) in the context of medical imaging is undeniable. In MRI, it could enable shorter acquisition times while in CT, it has the potential to reduce the ionizing radiation dose imparted to patients. However, images reconstructed using a CS-based approach often show an unusual texture and a potential loss in spatial resolution. The prior image constrained compressed sensing (PICCS) algorithm has been shown to enable accurate image reconstruction at lower levels of sampling. This study systematically evaluates an implementation of PICCS applied to myocardial perfusion imaging with respect to two parameters of its objective function. The prior image parameter ? was shown here to yield an optimal image quality in the range 0.4 to 0.5. A quantitative evaluation in terms of temporal resolution, spatial resolution, noise level, noise texture, and reconstruction accuracy was performed.

Thériault Lauzier, Pascal; Tang, Jie; Chen, Guang-Hong

2012-03-01

328

Quantitative toxicology: interlaboratory and intermethod evaluation in New York State.  

PubMed

The New York State Department of Health has conducted a proficiency evaluation program in quantitative toxicology since 1974. Serum samples containing a barbiturate and phenytoin, together with either glutethimide, procainamide, or theophylline, are sent to participating laboratories quarterly. Within the first two years of the program the percentage of laboratories able to quantitate 75% of the test samples to within 25% of the gravimetric values increased from 25 (1974-1975) to 40% (1975-1976). This improvement was partly due to licensure requirements, improved technology for sample preparation and analysis, and the availability of better quality-control practice. An obstacle to obtaining uniform accuracy is the lack of adequate calibration or testing materials. To overcome these obstacles, pure drugs are weighed into a bovine serum matrix, and the weights are confirmed by reference laboratories and used as the target values in the testing program. Comparison of the methods used by participants in this program for barbiturate and phenytoin yielded equations different from those found in other method evaluations. PMID:343948

Buhl, S N; Kowalski, P; Vanderlinde, R E

1978-03-01

329

A comparison between ultrasonic array beamforming and super resolution imaging algorithms for non-destructive evaluation.  

PubMed

In this paper the total focusing method, the so called gold standard in classical beamforming, is compared with the widely used time-reversal MUSIC super resolution technique in terms of its ability to resolve closely spaced scatterers in a solid. The algorithms are tested with simulated and experimental array data, each containing different noise levels. The performance of the algorithms is evaluated in terms of lateral resolution and sensitivity to noise. It is shown that for the weak noise situation (SNR>20 dB), time-reversal MUSIC provides significantly enhanced lateral resolution when compared to the total focusing method, breaking the diffraction limit. However, for higher noise levels, the total focusing method is shown to be robust, whilst the performance of time-reversal MUSIC is degraded. The influence of multiple scattering on the imaging algorithms is also investigated and shown to be small. PMID:24457032

Fan, Chengguang; Caleap, Mihai; Pan, Mengchun; Drinkwater, Bruce W

2014-09-01

330

Comparison between beamforming and super resolution imaging algorithms for non-destructive evaluation  

SciTech Connect

In this paper the performance of total focusing method is compared with the widely used time-reversal MUSIC super resolution technique. The algorithms are tested with simulated and experimental ultrasonic array data, each containing different noise levels. The simulated time domain signals allow the effects of array geometry, frequency, scatterer location, scatterer size, scatterer separation and random noise to be carefully controlled. The performance of the imaging algorithms is evaluated in terms of resolution and sensitivity to random noise. It is shown that for the low noise situation, time-reversal MUSIC provides enhanced lateral resolution when compared to the total focusing method. However, for higher noise levels, the total focusing method shows robustness, whilst the performance of time-reversal MUSIC is significantly degraded.

Fan, Chengguang [College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha 410073, PR China and Department of Mechanical Engineering, University of Bristol, Queen's Building, University Walk, Bristol BS8 1TR (United Kingdom); Drinkwater, Bruce W. [Department of Mechanical Engineering, University of Bristol, Queen's Building, University Walk, Bristol BS8 1TR (United Kingdom)

2014-02-18

331

Observation of the charged defect migration that causes the degradation of double-Schottky barriers using a nondestructive quantitative profiling technique  

NASA Astrophysics Data System (ADS)

The migration and neutralization of charged defect ions during the degradation of a double-Schottky barrier are observed by performing nondestructive pulsed electroacoustic measurements on ZnO bicrystals. This offers the possibility to experimentally access the predicted defect migration behavior and provides a solid foundation to validate the theoretical aging model for electroceramics. Theoretical modeling of the acoustic attenuation effects during measurements is also discussed to understand and validate the experimental results, gaining insight into the widely used acoustic technique.

Cheng, Chenlu; He, Jinliang; Hu, Jun

2014-09-01

332

Nondestructive analysis and development  

NASA Technical Reports Server (NTRS)

This final report summarizes the achievements of project #4 of the NASA/UCF Cooperative Agreement from January 1990 to December 1992. The objectives of this project are to review NASA's NDE program at Kennedy Space Center (KSC) and recommend means for enhancing the present testing capabilities through the use of improved or new technologies. During the period of the project, extensive development of a reliable nondestructive, non-contact vibration technique to determine and quantify the bond condition of the thermal protection system (TPS) tiles of the Space Shuttle Orbiter was undertaken. Experimental modal analysis (EMA) is used as a non-destructive technique for the evaluation of Space Shuttle thermal protection system (TPS) tile bond integrity. Finite element (FE) models for tile systems were developed and were used to generate their vibration characteristics (i.e. natural frequencies and mode shapes). Various TPS tile assembly configurations as well as different bond conditions were analyzed. Results of finite element analyses demonstrated a drop in natural frequencies and a change in mode shapes which correlate with both size and location of disbond. Results of experimental testing of tile panels correlated with FE results and demonstrated the feasibility of EMA as a viable technique for tile bond verification. Finally, testing performed on the Space Shuttle Columbia using a laser doppler velocimeter demonstrated the application of EMA, when combined with FE modeling, as a non-contact, non-destructive bond evaluation technique.

Moslehy, Faissal A.

1993-01-01

333

3D Ultrasonic Non-destructive Evaluation of Spot Welds Using an Enhanced Total Focusing Method  

NASA Astrophysics Data System (ADS)

Spot welds are used to join sheets of metals in the automotive industry. When spot weld quality is evaluated using conventional ultrasonic manual pulse-echo method, the reliability of the inspection is affected by selection of the probe diameter and the positioning of the probe in the weld center. The application of a 2D matrix array is a potential solution to the aforementioned problems. The objective of this work was to develop a signal processing algorithm to reconstruct the 3D spot weld volume showing the size of the nugget and the defects in it. In order to achieve this, the conventional total focusing method was enhanced by taking into account the directivities of the single elements of the array and the divergence of the ultrasonic beam due to the propagation distance. Enhancements enabled a reduction in the background noise and uniform sensitivity at different depths to be obtained. The proposed algorithm was verified using a finite element model of ultrasonic wave propagation simulating three common spot weld conditions: a good weld, an undersized weld, and a weld containing a pore. The investigations have demonstrated that proposed method enables the determination of the size of the nugget and detection of discontinuities.

Jasiuniene, Elena; Samaitis, Vykintas; Mazeika, Liudas; Sanderson, Ruth

2014-12-01

334

Nondestructive testing  

SciTech Connect

Problems and defects of all kinds arise in the development and use of mechanical devices, electrical equipment, hydraulic systems, transportation mechanisms and the like. However, an extremely wide range of nondestructive testing (NDT) methods are available to help you examine these different problems and various defects in an assortment of materials under varying circumstances. It is imperative that you select the best method to solve a particular problem. And that requires a sufficient understanding of the basic processes involved to realize the advantages of each NDT method available. In addition to practical hints and pertinent comments for the resolution of day to day problems, this book gives sufficient basic theory to comprehend the principles of each method so that the most appropriate can be selected and used to its fullest advantage. Typical illustrative calculations and a comprehensive bibliography are provided.

Cartz, L.

1995-12-31

335

Quantitative methodology of evaluating surgeon performance in laparoscopic surgery.  

PubMed

Quantitative performance and skill assessments are critical for evaluating the progress of surgical residents and the efficacy of different training programs. Current evaluation methods are subjective and potentially unreliable, so there is a need for objective methods to evaluate surgical performance. We identify a feasible method to measure kinematic data in the live operating room setting and to assess the repeatability of an analysis method based on a hierarchical decomposition of surgical tasks. We used an optoelectronic motion analysis system to acquire postural data and tool tip trajectories of one expert surgeon over a period of four months. To assess repeatability of performance measures, we created a hierarchical decomposition diagram describing the procedure in terms of surgical tasks, tool sequences and fundamental tool actions. From the kinematic data, we extracted characteristic measures of individual tool actions and compared these measured distributions using the Kolmogorov-Smirnov statistic. The comparisons of distributions show consistent performance over time by a trained surgeon and little effect from patient variability, and so are likely reliable measures of performance. An expanded set of reliable kinematic measures will form the basis for quantifying surgical skill and should be useful in validating surgical simulations for use in training, certifying surgeons and designing and evaluating new surgical tools. PMID:15458102

McBeth, Paul B; Hodgson, Antony J; Nagy, Alex G; Qayumi, Karim

2002-01-01

336

Nuclear medicine and imaging research (instrumentation and quantitative methods of evaluation)  

SciTech Connect

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.

Beck, R.N.; Cooper, M.; Chen, C.T.

1992-07-01

337

Steam Generator Group Project: Task 9 final report, Nondestructive evaluation round robin: Volume 2, Raw inspection data  

Microsoft Academic Search

The Steam Generator Group Project (SGGP) is using the retired-from service Surry 2A pressurized water reactor steam generator as a test bed to investigate the reliability and effectiveness of inservice nondestructive eddy current inspection equipment and procedures. The information developed will provide the technical basis for updating the Regulatory Guides governing inservice inspection and tube plugging criteria of steam generators.

H. Harty; R. H. Ferris; A. S. Birks

1989-01-01

338

Steam Generator Group Project: Task 9 final report, Nondestructive evaluation round robin: Volume 1, Description and summary data  

Microsoft Academic Search

The Steam Generator Group Project (SGGP) is using the retired-from-service Surry 2A pressurized water reactor steam generator as a test bed to investigate the reliability and effectiveness of inservice nondestructive eddy current inspection equipment and procedures. The information developed will provide the technical basis for updating the Regulatory Guides governing inservice inspection and tube plugging criteria of steam generators. This

H. Harty; R. H. Ferris; A. S. Birks

1989-01-01

339

Evaluation of Random Errors of the Multimodel Method of Nondestructive Determination of the Thermophysical Properties of Solid Materials  

NASA Astrophysics Data System (ADS)

We present the results of an analysis of random errors incurring in the multimodel method of nondestructive determination of the thermophysical properties of solid materials. We have formulated recommendations for decreasing these errors by means of selecting operational and design parameters of a measuring device used for implementing the aforementioned method.

Zhukov, N. P.; Mainikova, N. F.; Rogov, I. V.; Antonov, A. O.

2014-11-01

340

Structural Anomalies Detected in Ceramic Matrix Composites Using Combined Nondestructive Evaluation and Finite Element Analysis (NDE and FEA)  

NASA Technical Reports Server (NTRS)

Most reverse engineering approaches involve imaging or digitizing an object and then creating a computerized reconstruction that can be integrated, in three dimensions, into a particular design environment. The rapid prototyping technique builds high-quality physical prototypes directly from computer-aided design files. This fundamental technique for interpreting and interacting with large data sets is being used here via Velocity2 (an integrated image-processing software, ref. 1) using computed tomography (CT) data to produce a prototype three-dimensional test specimen model for analyses. A study at the NASA Glenn Research Center proposes to use these capabilities to conduct a combined nondestructive evaluation (NDE) and finite element analysis (FEA) to screen pretest and posttest structural anomalies in structural components. A tensile specimen made of silicon nitrite (Si3N4) ceramic matrix composite was considered to evaluate structural durability and deformity. Ceramic matrix composites are being sought as candidate materials to replace nickel-base superalloys for turbine engine applications. They have the unique characteristics of being able to withstand higher operating temperatures and harsh combustion environments. In addition, their low densities relative to metals help reduce component mass (ref. 2). Detailed three-dimensional volume rendering of the tensile test specimen was successfully carried out with Velocity2 (ref. 1) using two-dimensional images that were generated via computed tomography. Subsequent, three-dimensional finite element analyses were performed, and the results obtained were compared with those predicted by NDE-based calculations and experimental tests. It was shown that Velocity2 software can be used to render a three-dimensional object from a series of CT scan images with a minimum level of complexity. The analytical results (ref. 3) show that the high-stress regions correlated well with the damage sites identified by the CT scans and the experimental data. Furthermore, modeling of the voids collected via NDE offered an analytical advantage that resulted in more accurate assessments of the material s structural strength. The top figure shows a CT scan image of the specimen test section illustrating various hidden structural entities in the material and an optical image of the test specimen considered in this study. The bottom figure represents the stress response predicted from the finite element analyses (ref .3 ) for a selected CT slice where it clearly illustrates the correspondence of the high stress risers due to voids in the material with those predicted by the NDE. This study is continuing, and efforts are concentrated on improving the modeling capabilities to imitate the structural anomalies as detected.

Abdul-Aziz, Ali; Baaklini, George Y.; Bhatt, Ramakrishna T.

2003-01-01

341

Evaluation of statistical approaches in quantitative nursing research.  

PubMed

The purposes of this study were to (a) develop a tool to assess statistical methods and (b) use the tool to evaluate recently published quantitative research. We rated the statistical approaches used in 152 studies published in the 5 top impact-factor nursing research journals from September 2005 to August 2007. Studies were generally of high quality; 45% scored between 80% and 100%, and 22% achieved a score of 100%. Predictors of high scores were interdisciplinary authorship, a statistician coauthor, and the number of aims. The authors conclude that studies published in high impact-factor nursing journals are statistically sound and provide a solid foundation for evidence-based practice. PMID:19448031

Gross Cohn, Elizabeth; Haomiao Jia; Larson, Elaine

2009-08-01

342

A quantitative evaluation of the public response to climate engineering  

NASA Astrophysics Data System (ADS)

Atmospheric greenhouse gas concentrations continue to increase, with CO2 passing 400 parts per million in May 2013. To avoid severe climate change and the attendant economic and social dislocation, existing energy efficiency and emissions control initiatives may need support from some form of climate engineering. As climate engineering will be controversial, there is a pressing need to inform the public and understand their concerns before policy decisions are taken. So far, engagement has been exploratory, small-scale or technique-specific. We depart from past research to draw on the associative methods used by corporations to evaluate brands. A systematic, quantitative and comparative approach for evaluating public reaction to climate engineering is developed. Its application reveals that the overall public evaluation of climate engineering is negative. Where there are positive associations they favour carbon dioxide removal (CDR) over solar radiation management (SRM) techniques. Therefore, as SRM techniques become more widely known they are more likely to elicit negative reactions. Two climate engineering techniques, enhanced weathering and cloud brightening, have indistinct concept images and so are less likely to draw public attention than other CDR or SRM techniques.

Wright, Malcolm J.; Teagle, Damon A. H.; Feetham, Pamela M.

2014-02-01

343

Evaluation of a Virucidal Quantitative Carrier Test for Surface Disinfectants  

PubMed Central

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

Rabenau, Holger F.; Steinmann, Jochen; Rapp, Ingrid; Schwebke, Ingeborg; Eggers, Maren

2014-01-01

344

Evaluation of a virucidal quantitative carrier test for surface disinfectants.  

PubMed

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

Rabenau, Holger F; Steinmann, Jochen; Rapp, Ingrid; Schwebke, Ingeborg; Eggers, Maren

2014-01-01

345

Nondestructive test of regenerative chambers  

NASA Technical Reports Server (NTRS)

Flat panels simulating internally cooled regenerative thrust chamber walls were fabricated by electroforming, brazing and diffusion bonding to evaluate the feasibility of nondestructive evaluation techniques to detect bonds of various strength integrities. Ultrasonics, holography, and acoustic emission were investigated and found to yield useful and informative data regarding the presence of bond defects in these structures.

Malone, G. A.; Stauffis, R.; Wood, R.

1972-01-01

346

Quantitative methods for somatosensory evaluation in atypical odontalgia.  

PubMed

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

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

2015-01-01

347

Quantitative evaluation of activation state in functional brain imaging.  

PubMed

Neuronal activity can evoke the hemodynamic change that gives rise to the observed functional magnetic resonance imaging (fMRI) signal. These increases are also regulated by the resting blood volume fraction (V (0)) associated with regional vasculature. The activation locus detected by means of the change in the blood-oxygen-level-dependent (BOLD) signal intensity thereby may deviate from the actual active site due to varied vascular density in the cortex. Furthermore, conventional detection techniques evaluate the statistical significance of the hemodynamic observations. In this sense, the significance level relies not only upon the intensity of the BOLD signal change, but also upon the spatially inhomogeneous fMRI noise distribution that complicates the expression of the results. In this paper, we propose a quantitative strategy for the calibration of activation states to address these challenging problems. The quantitative assessment is based on the estimated neuronal efficacy parameter [Formula: see text] of the hemodynamic model in a voxel-by-voxel way. It is partly immune to the inhomogeneous fMRI noise by virtue of the strength of the optimization strategy. Moreover, it is easy to incorporate regional vascular information into the activation detection procedure. By combining MR angiography images, this approach can remove large vessel contamination in fMRI signals, and provide more accurate functional localization than classical statistical techniques for clinical applications. It is also helpful to investigate the nonlinear nature of the coupling between synaptic activity and the evoked BOLD response. The proposed method might be considered as a potentially useful complement to existing statistical approaches. PMID:22569644

Hu, Zhenghui; Ni, Pengyu; Liu, Cong; Zhao, Xiaohu; Liu, Huafeng; Shi, Pengcheng

2012-10-01

348

Non-destructive flavour evaluation of red onion (Allium cepa L.) ecotypes: an electronic-nose-based approach.  

PubMed

This work reports preliminary results on the potential of a metal oxide sensor (MOS)-based electronic nose, as a non-destructive method to discriminate three "Tropea Red Onion" PGI ecotypes (TrT, TrMC and TrA) from each other and the common red onion (RO), which is usually used to counterfeit. The signals from the sensor array were processed using a canonical discriminant function analysis (DFA) pattern recognition technique. The DFA on onion samples showed a clear separation among the four onion groups with an overall correct classification rate (CR) of 97.5%. Onion flavour is closely linked to pungency and thus to the pyruvic acid content. The e-nose analysis results are in good agreement with pyruvic acid analysis. This work demonstrated that artificial olfactory systems have potential for use as an innovative, rapid and specific non-destructive technique, and may provide a method to protect food products against counterfeiting. PMID:23790864

Russo, Mariateresa; di Sanzo, Rosa; Cefaly, Vittoria; Carabetta, Sonia; Serra, Demetrio; Fuda, Salvatore

2013-11-15

349

Qualitative and quantitative evaluation of solvent systems for countercurrent separation.  

PubMed

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

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

2015-01-16

350

Aging material evaluation and studies by non-destructive techniques (AMES-NDT) — a European network project  

Microsoft Academic Search

This paper presents results obtained in a round-robin action organized in a concerted action of ten partners in the EURATOM program of the European Community. The objective of the research was to document the state of the art of available non-destructive testing (NDT) techniques in order to characterize material aging phenomena based on a reduction of Charpy-V energy and a

Gerd Dobmann; Luigi Debarberis; Jean-François Coste

2001-01-01

351

Nondestructive quantitative mapping of impurities and point defects in thin films: Ga and V{sub Zn} in ZnO:Ga  

SciTech Connect

Ga-doped ZnO (GZO) films grown by pulsed-laser deposition on quartz and other lattice-mismatched substrates can routinely attain resistivities of 2?×?10{sup ?4} ?·cm and thus compete with Sn-doped In{sub 2}O{sub 3} (ITO) in large-area transparent-electrode applications. Nondestructive, high-resolution (1-mm) maps of thickness d, concentration n, and mobility ? on such films can be obtained automatically from commercial spectroscopic ellipsometers. From n and ?, degenerate-electron scattering theory yields donor N{sub D} and acceptor N{sub A} concentrations at each point. Finally, N{sub D} and N{sub A} can be identified as [Ga] and [V{sub Zn}], respectively, demonstrating high-density mapping of impurities and point defects in a semiconductor thin film.

Look, David C., E-mail: david.look@wright.edu [Semiconductor Research Center, Wright State University, 3640 Colonel Glenn Hwy., Dayton, Ohio 45435 (United States); Wyle, 2601 Mission Point Blvd., Dayton, Ohio 45431 (United States); Air Force Research Laboratory Sensors Directorate, 2241 Avionics Circle, Wright-Patterson AFB, Ohio 45433 (United States); Leedy, Kevin D.; Agresta, Donald L. [Air Force Research Laboratory Sensors Directorate, 2241 Avionics Circle, Wright-Patterson AFB, Ohio 45433 (United States)

2014-06-16

352

Quantitative evaluation of phase processing approaches in susceptibility weighted imaging  

NASA Astrophysics Data System (ADS)

Susceptibility weighted imaging (SWI) takes advantage of the local variation in susceptibility between different tissues to enable highly detailed visualization of the cerebral venous system and sensitive detection of intracranial hemorrhages. Thus, it has been increasingly used in magnetic resonance imaging studies of traumatic brain injury as well as other intracranial pathologies. In SWI, magnitude information is combined with phase information to enhance the susceptibility induced image contrast. Because of global susceptibility variations across the image, the rate of phase accumulation varies widely across the image resulting in phase wrapping artifacts that interfere with the local assessment of phase variation. Homodyne filtering is a common approach to eliminate this global phase variation. However, filter size requires careful selection in order to preserve image contrast and avoid errors resulting from residual phase wraps. An alternative approach is to apply phase unwrapping prior to high pass filtering. A suitable phase unwrapping algorithm guarantees no residual phase wraps but additional computational steps are required. In this work, we quantitatively evaluate these two phase processing approaches on both simulated and real data using different filters and cutoff frequencies. Our analysis leads to an improved understanding of the relationship between phase wraps, susceptibility effects, and acquisition parameters. Although homodyne filtering approaches are faster and more straightforward, phase unwrapping approaches perform more accurately in a wider variety of acquisition scenarios.

Li, Ningzhi; Wang, Wen-Tung; Sati, Pascal; Pham, Dzung L.; Butman, John A.

2012-03-01

353

Nondestructive indices of trace element exposure in squamate reptiles  

E-print Network

Nondestructive indices of trace element exposure in squamate reptiles W.A. Hopkins a,b, *, J.H. Roe'': Nondestructive sampling techniques, such as blood samples and tail clips, can be used to evaluate as development of nondestructive sampling techniques useful for assessing and monitoring contaminant exposure

Hopkins, William A.

354

Current and future developments in civil aircraft non-destructive evaluation from an operator's point of view  

NASA Technical Reports Server (NTRS)

In June, 1988, the first International Conference on aging aircraft was held to address nondestructive tests (NDT) of aging aircraft and other issues. From this meeting, a research program was initiated and funded by the FAA. As a result of this program, a lot of work has been done to study current NDT practices in the aviation industry and secondly, to research and develop new NDT methods to improve the reliability and efficiency of in-service inspection of aircraft structures and powerplants. The following is an overview of the current and future developments in civil aircraft NDT, as viewed by an air carrier and the concerns for NDT in the future.

Register, Jeff

1992-01-01

355

Probing metal solidification nondestructively  

E-print Network

- 1 - Probing metal solidification nondestructively April 11, 2014 Los Alamos researchers and collaborators have used nondestructive imaging techniques to study the solidification of metal alloy samples time that high-energy protons have been used to nondestructively image a large metal sample during

356

A Quantitative Evaluation of Video-based 3D Person Tracking  

Microsoft Academic Search

The Bayesian estimation of 3D human motion from video sequences is quantitatively evaluated using synchronized, multi-camera, calibrated video and 3D ground truth poses acquired with a commercial motion capture system. While many methods for human pose estimation and tracking have been proposed, to date there has been no quantitative comparison. Our goal is to evaluate how different design choices influence

A. O. Balan; Leonid Sigal; Michael J. Black

2005-01-01

357

Of Categorizers and Describers: An Evaluation of Quantitative Measures for Tagging Motivation  

E-print Network

Of Categorizers and Describers: An Evaluation of Quantitative Measures for Tagging Motivation.strohmaier@tugraz.at ABSTRACT While recent research has advanced our understanding about the structure and dynamics of social empiri- cal findings from qualitative and quantitative evaluations of the measures on real world tagging

358

Development of the Non-Destructive Evaluation System Using an Eddy Current Probe for Detection of Fatigue Damage in a Stainless Steel  

SciTech Connect

The non-destructive evaluation system which is developed using an eddy current probe to evaluate fatigue damage in an austenitic stainless steel is reported in this paper. This probe is composed of the ferrite core and two pick-up coils connected differentially. The eddy current induced by the excitation coil is disarranged by nonuniform distribution of electromagnetic characteristics due to fatigue damage. The structural function of the eddy current probe proposed, enable to detect the eddy current disarrangement by fatigue damage. This probe detects the change of electromagnetic characteristics in the direction of X. In this paper, SUS304, a austenitic stainless steel was used as the sample. The experimental results show that the output voltage of the probe clearly depends on the number of stress cycles.

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

2006-03-06

359

Nondestructive inspection of kinetic bonding by eddy current method  

NASA Astrophysics Data System (ADS)

Kinetic bonding is a welding procedure in which two metals are joined together by forcing them to collide under high pressure and at high velocity by explosive detonation. Applied to steam condenser tube/tube-sheet welding, this method has demonstrated considerable reduction in cost and improvement in welding speed and effectiveness. Presented in this paper is the result of a theoretical study conducted to determine the suitability of ``eddy current method'' for nondestructively testing the kinetically bonded tube/tube-sheet region. The study shows that an eddy current probe is sensitive enough for this application and an advanced state-of-the-art instrumentation may be needed for quantitative evaluation.

Palanisamy, R.

1984-03-01

360

Nondestructive Damage Detection in General Beams  

E-print Network

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...

Dincal, Selcuk

2010-12-08

361

Quantitative evaluation of stiffness of commercial suture materials.  

PubMed

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

Chu, C C; Kizil, Z

1989-03-01

362

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...

363

Progress in evaluation and improvement in nondestructive examination reliability for inservice inspection of Light Water Reactors (LWRs) and characterize fabrication flaws in reactor pressure vessels  

SciTech Connect

This paper is a review of the work conducted under two programs. One (NDE Reliability Program) is a multi-year program addressing the reliability of nondestructive evaluation (NDE) for the inservice inspection (ISI) of light water reactor components. This program examines the reliability of current NDE, the effectiveness of evolving technologies, and provides assessments and recommendations to ensure that the NDE is applied at the right time, in the right place with sufficient effectiveness that defects of importance to structural integrity will be reliably detected and accurately characterized. The second program (Characterizing Fabrication Flaws in Reactor Pressure Vessels) is assembling a data base to quantify the distribution of fabrication flaws that exist in US nuclear reactor pressure vessels with respect to density, size, type, and location. These programs will be discussed as two separate sections in this report. 4 refs., 7 figs.

Doctor, S.R.; Bowey, R.E.; Good, M.S.; Friley, J.R.; Kurtz, R.J.; Simonen, F.A.; Taylor, T.T.; Heasler, P.G.; Andersen, E.S.; Diaz, A.A.; Greenwood, M.S.; Hockey, R.L.; Schuster, G.J.; Spanner, J.C.; Vo, T.V.

1991-10-01

364

Application of non-destructive impedance-based monitoring technique for cyclic fatigue evaluation of endodontic nickel-titanium rotary instruments.  

PubMed

This study investigates the application of non-destructive testing based on the impedance theory in the cyclic fatigue evaluation of endodontic Ni-Ti rotary instruments. Fifty Ni-Ti ProTaper instruments were divided into five groups (n=10 in Groups A to E). Groups A to D were subjected to cyclic fatigue within an artificial canal (Group E was the control group). The mean value of the total life limit (TLL), defined as the instrument being rotated until fracture occurred was found to be 104 s in Group A. Each rotary instrument in Groups B, C and D were rotated until the tested instruments reached 80% (84 s), 60% (62 s) and 40% (42 s) of the TLL. After fatigue testing, each rotary instrument was mounted onto a custom-developed non-destructive testing device to give the tip of the instrument a progressive sideways bend in four mutually perpendicular directions to measure the corresponding impedance value (including the resistance and the reactance). The results indicated that the impedance value showed the same trend as the resistance, implying that the impedance was primarily affected by the resistance. The impedance value for the instruments in the 80% and 60% TLL groups increased by about 6 m? (about 7.5%) more than that of the instruments in the intact and 40% TLL groups. The SEM analysis result showed that crack striations were only found at the tip of the thread on the cracked surface of the instrument, consistent with the impedance measurements that found the impedance value of the cracked surface to be significantly different from those in other surfaces. These findings indicate that the impedance value may represent an effective parameter for evaluating the micro-structural status of Ni-Ti rotary instruments subjected to fatigue loading. PMID:21251866

Chang, Yau-Zen; Liu, Mou-Chuan; Pai, Che-An; Lin, Chun-Li; Yen, Kuang-I

2011-06-01

365

Non-destructive evaluation of chlorophyll content in quinoa and amaranth leaves by simple and multiple regression analysis of RGB image components.  

PubMed

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

Riccardi, M; Mele, G; Pulvento, C; Lavini, A; d'Andria, R; Jacobsen, S-E

2014-06-01

366

Nondestructive biomarkers in ecotoxicology.  

PubMed Central

The aim of this article is to attempt a concise review of the state of the art of the nondestructive biomarkers approach in vertebrates, establishing a consensus on the most useful and sensitive nondestructive biomarker techniques, and proposing research priorities for the development and validation of this promising methodology. The following topics are discussed: the advantages of the use of nondestructive strategies in biomonitoring programs and the research fields in which nondestructive biomarkers can be applied; the biological materials suitable for nondestructive biomarkers and residue analysis in vertebrates; which biomarkers lend themselves to noninvasive techniques; and the validation and implementation strategy of the nondestructive biomarker approach. Examples of applications of this methodology in the hazard assessment of endangered species are also presented. Images Figure 1. C PMID:7713034

Fossi, M C

1994-01-01

367

Methods for quantitative image quality evaluation of MRI parallel reconstructions: detection and perceptual difference model  

Microsoft Academic Search

Many reconstruction algorithms are being proposed for parallel magnetic resonance imaging (MRI), which uses multiple coils and subsampled k-space data, and a quantitative method for comparison of algorithms is sorely needed. On such images, we compared three methods for quantitative image quality evaluation: human detection, computer detection model and a computer perceptual difference model (PDM). One-quarter sampling and three different

Yuhao Jiang; Donglai Huo; David L. Wilson

2007-01-01

368

A review of methods for quantitative evaluation of axial vertebral rotation  

PubMed Central

Quantitative evaluation of axial vertebral rotation is essential for the determination of reference values in normal and pathological conditions and for understanding the mechanisms of the progression of spinal deformities. However, routine quantitative evaluation of axial vertebral rotation is difficult and error-prone due to the limitations of the observer, characteristics of the observed vertebral anatomy and specific imaging properties. The scope of this paper is to review the existing methods for quantitative evaluation of axial vertebral rotation from medical images along with all relevant publications, which may provide a valuable resource for studying the existing methods or developing new methods and evaluation strategies. The reviewed methods are divided into the methods for evaluation of axial vertebral rotation in 2D images and the methods for evaluation of axial vertebral rotation in 3D images. Key evaluation issues and future considerations, supported by the results of the overview, are also discussed. PMID:19242736

Pernuš, Franjo; Likar, Boštjan

2009-01-01

369

Quantitative autoradiographic microimaging in the development and evaluation of radiopharmaceuticals  

SciTech Connect

Autoradiographic (ARG) microimaging is the method for depicting biodistribution of radiocompounds with highest spatial resolution. ARG is applicable to gamma, positron and negatron emitting radiotracers. Dual or multiple-isotope studies can be performed using half-lives and energies for discrimination of isotopes. Quantitation can be performed by digital videodensitometry and by newer filmless technologies. ARG`s obtained at different time intervals provide the time dimension for determination of kinetics.

Som, P. [Brookhaven National Lab., Upton, NY (United States); Oster, Z.H. [State Univ. of New York, Stony Brook, NY (United States)

1994-04-01

370

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

E-print Network

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. ...

Cardin, Michel-Alexandre, 1979-

2011-01-01

371

Exploratory nondestructive evaluation (NDE) research for advanced materials and processes: Volume 3 -- Interactive multimedia computer based training (IMCBT) for nondestructive evaluation/inspection (NDE/I) personnel. Final report, 1 July 1995--30 April 1998  

SciTech Connect

Interactive Multimedia Computer Based Training (IMCBT) for Nondestructive Inspection (NDE/I) Personnel: Computer Based Training (CBT) is a highly effective method for industrial training that has been growing in popularity. Text, graphics, sound, movies and animation enhance the learning activity. Interactive Multimedia CBT (IMCBT) allows students to learn in an environment where the training material is presented on a computer workstation and uses student interaction and feedback in the learning process. This technology has been used in the aerospace industry for aircraft maintenance and flight training and is growing in many operation training areas. The cost of development of IMCBT material is significantly more expensive than traditional training material, but an hour of IMCBT material can contain more information than an hour of traditional training material since information is transferred faster and with higher retention. Because IMCBT delivers training at lower cost, the overall benefit of IMCBT has been found to be in the range of 40% to 60% cost savings. The application of IMCBT for NDE/I training did show an overwhelmingly positive acceptance of the incorporation of IMCBT for NDE/I personnel within existing training structures. A CD-ROM package called INSPECT (Interactive Student Paced Eddy Current Training) has demonstrate various advanced aspects of potential IMCBT lessons. The INSPECT CD demonstration was reviewed by Air Force and industry professionals, as well as a group of high school students to gauge novice response. The prototype was found to be appealing and to have significant potential as a useful teaching tool. A large majority of the professional reviewers stated they would like to have complete CBT modules like INSPECT for some aspect of their NDE/I training.

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

1998-07-01

372

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

PubMed

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

Hellen, Adam; Mandelis, Andreas; Finer, Yoav; Amaechi, Bennett T

2011-07-01

373

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

NASA Astrophysics Data System (ADS)

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.

Hellen, Adam; Mandelis, Andreas; Finer, Yoav; Amaechi, Bennett T.

2011-07-01

374

A review of methods for quantitative evaluation of axial vertebral rotation  

Microsoft Academic Search

Quantitative evaluation of axial vertebral rotation is essential for the determination of reference values in normal and pathological\\u000a conditions and for understanding the mechanisms of the progression of spinal deformities. However, routine quantitative evaluation\\u000a of axial vertebral rotation is difficult and error-prone due to the limitations of the observer, characteristics of the observed\\u000a vertebral anatomy and specific imaging properties. The

Tomaž Vrtovec; Franjo Pernuš; Boštjan Likar

2009-01-01

375

Digital holographic microscopy for quantitative cell dynamic evaluation during laser microsurgery.  

PubMed

Digital holographic microscopy allows determination of dynamic changes in the optical thickness profile of a transparent object with sub-wavelength accuracy. Here, we report a quantitative phase laser microsurgery system for evaluation of cellular/ sub-cellular dynamic changes during laser micro-dissection. The proposed method takes advantage of the precise optical manipulation by the laser microbeam and quantitative phase imaging by digital holographic microscopy with high spatial and temporal resolution. This system will permit quantitative evaluation of the damage and/or the repair of the cell or cell organelles in real time. PMID:19582118

Yu, Lingfeng; Mohanty, Samarendra; Zhang, Jun; Genc, Suzanne; Kim, Myung K; Berns, Michael W; Chen, Zhongping

2009-07-01

376

Digital holographic microscopy for quantitative cell dynamic evaluation during laser microsurgery  

PubMed Central

Digital holographic microscopy allows determination of dynamic changes in the optical thickness profile of a transparent object with subwavelength accuracy. Here, we report a quantitative phase laser microsurgery system for evaluation of cellular/ sub-cellular dynamic changes during laser micro-dissection. The proposed method takes advantage of the precise optical manipulation by the laser microbeam and quantitative phase imaging by digital holographic microscopy with high spatial and temporal resolution. This system will permit quantitative evaluation of the damage and/or the repair of the cell or cell organelles in real time. PMID:19582118

Yu, Lingfeng; Mohanty, Samarendra; Zhang, Jun; Genc, Suzanne; Kim, Myung K.; Berns, Michael W.; Chen, Zhongping

2010-01-01

377

A New Simple Interferometer for Obtaining Quantitatively Evaluable Flow Patterns  

NASA Technical Reports Server (NTRS)

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.

Erdmann, S F

1953-01-01

378

A new fiber-optic non-contact compact laser-ultrasound scanner for fast non-destructive testing and evaluation of aircraft composites.  

PubMed

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

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

2014-03-21

379

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)

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.

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

2014-03-01

380

A lighting metric for quantitative evaluation of accent lighting systems  

NASA Astrophysics Data System (ADS)

Accent lighting is critical for artwork and sculpture lighting in museums, and subject lighting for stage, Film and television. The research problem of designing effective lighting in such settings has been revived recently with the rise of light-emitting-diode-based solid state lighting. In this work, we propose an easy-to-apply quantitative measure of the scene's visual quality as perceived by human viewers. We consider a well-accent-lit scene as one which maximizes the information about the scene (in an information-theoretic sense) available to the user. We propose a metric based on the entropy of the distribution of colors, which are extracted from an image of the scene from the viewer's perspective. We demonstrate that optimizing the metric as a function of illumination configuration (i.e., position, orientation, and spectral composition) results in natural, pleasing accent lighting. We use a photorealistic simulation tool to validate the functionality of our proposed approach, showing its successful application to two- and three-dimensional scenes.

Acholo, Cyril O.; Connor, Kenneth A.; Radke, Richard J.

2014-09-01

381

Quantitative Evaluation of Hæmagglutination by means of a Density Column  

Microsoft Academic Search

THE ideal substance for evaluation of haemagglutination by means of a density column must not enhance rouleaux formation or produce haemolysis (osmotic fragility ; mechanical fragility). Such a substance should not increase the sedimentation of single cells, but only of aggregates. Previous work1 has shown that fibrinogen, certain gums, gelatin, glycogen, pectin, agar-agar, hyaluronic acid, polyacrylic acid and deoxyribonucleic acid

Ch. Wunderly

1957-01-01

382

Quantitative and Qualitative Evaluation of Darpa Communicator Spoken Dialogue Systems  

Microsoft Academic Search

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

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

2001-01-01

383

Nuclear medicine and imaging research (instrumentation and quantitative methods of evaluation). Progress report, January 15, 1992--January 14, 1993  

SciTech Connect

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.

Beck, R.N.; Cooper, M.; Chen, C.T.

1992-07-01

384

Quantitative Evaluation of the Safety of X-by-Wire Architecture subject to EMI Perturbations  

E-print Network

Quantitative Evaluation of the Safety of X-by-Wire Architecture subject to EMI Perturbations Cédric. In this paper we propose a new approach to evaluate the impact of the EMI perturbations on the dependability, together with the EMI perturbations collected on the roads in France, is used to illustrate our approach. 1

Paris-Sud XI, Université de

385

A quantitative evaluation of the AVITEWRITE model of handwriting learning.  

PubMed

Much sensory-motor behavior develops through imitation, as during the learning of handwriting by children. Such complex sequential acts are broken down into distinct motor control synergies, or muscle groups, whose activities overlap in time to generate continuous, curved movements that obey an inverse relation between curvature and speed. The adaptive vector integration to endpoint handwriting (AVITEWRITE) model of Grossberg and Paine (2000) [A neural model of corticocerebellar interactions during attentive imitation and predictive learning of sequential handwriting movements. Neural Networks, 13, 999-1046] addressed how such complex movements may be learned through attentive imitation. The model suggested how parietal and motor cortical mechanisms, such as difference vector encoding, interact with adaptively-timed, predictive cerebellar learning during movement imitation and predictive performance. Key psychophysical and neural data about learning to make curved movements were simulated, including a decrease in writing time as learning progresses; generation of unimodal, bell-shaped velocity profiles for each movement synergy; size scaling with isochrony, and speed scaling with preservation of the letter shape and the shapes of the velocity profiles; an inverse relation between curvature and tangential velocity; and a two-thirds power law relation between angular velocity and curvature. However, the model learned from letter trajectories of only one subject, and only qualitative kinematic comparisons were made with previously published human data. The present work describes a quantitative test of AVITEWRITE through direct comparison of a corpus of human handwriting data with the model's performance when it learns by tracing the human trajectories. The results show that model performance was variable across the subjects, with an average correlation between the model and human data of 0.89+/-0.10. The present data from simulations using the AVITEWRITE model highlight some of its strengths while focusing attention on areas, such as novel shape learning in children, where all models of handwriting and the learning of other complex sensory-motor skills would benefit from further research. PMID:15664676

Paine, R W; Grossberg, S; Van Gemmert, A W A

2004-12-01

386

Quantitative evaluation of the major determinants of human gait.  

PubMed

Accurate knowledge of the isolated contributions of joint movements to the three-dimensional displacement of the center of mass (COM) is fundamental for understanding the kinematics of normal walking and for improving the treatment of gait disabilities. Saunders et al. (1953) identified six kinematic mechanisms to explain the efficient progression of the whole-body COM in the sagittal, transverse, and coronal planes. These mechanisms, referred to as the major determinants of gait, were pelvic rotation, pelvic list, stance knee flexion, foot and knee mechanisms, and hip adduction. The aim of the present study was to quantitatively assess the contribution of each major gait determinant to the anteroposterior, vertical, and mediolateral displacements of the COM over one gait cycle. The contribution of each gait determinant was found by applying the concept of an 'influence coefficient', wherein the partial derivative of the COM displacement with respect to a prescribed determinant was calculated. The analysis was based on three-dimensional measurements of joint angular displacements obtained from 23 healthy young adults walking at slow, normal and fast speeds. We found that hip flexion, stance knee flexion, and ankle-foot interaction (comprised of ankle plantarflexion, toe flexion and the displacement of the center of pressure) are the major determinants of the displacements of the COM in the sagittal plane, while hip adduction and pelvic list contribute most significantly to the mediolateral displacement of the COM in the coronal plane. Pelvic rotation and pelvic list contribute little to the vertical displacement of the COM at all walking speeds. Pelvic tilt, hip rotation, subtalar inversion, and back extension, abduction and rotation make negligible contributions to the displacements of the COM in all three anatomical planes. PMID:24582352

Lin, Yi-Chung; Gfoehler, Margit; Pandy, Marcus G

2014-04-11

387

Evaluation of quantitative aerosol techniques for use in bronchoprovocation studies.  

PubMed

To investigate airway physiology by use of inhaled aerosols, it is frequently necessary to measure the actual amount of material deposited on the airway wall as well as the site of particle deposition. To satisfy these needs, radiolabeled aerosols and gamma camera techniques have been used to measure regional deposition of inhaled particles. To make quantitative measurements of the amount deposited, previous investigators have used a "phantom" technique to indirectly calibrate the gamma camera for the attenuation of gamma rays through the lungs and chest wall. For this calibration, the phantom is a simulated lung containing a known amount of radioactivity. Radioactive counts emitted from the phantom are assumed to be attenuated in the same manner as the intact human lung. The present article describes a technique to determine directly the amount of inhaled aerosol deposited in the lung and simultaneously to calibrate the gamma camera for each individual subject. We used right angle light scattering and a gamma camera to measure individual values of the deposition fraction (DF) of inhaled aerosol deposited in the lung and the coefficient of attenuation (AC) of gamma rays in normal and obstructed lungs of human subjects. Radiolabeled monodisperse aerosols 1 and 2 microns in diameter were used. Knowledge of the activity of the inhaled aerosol (microcurie per liter), the volume inhaled, and the measured DF determined each subject's AC (counts per minute per microcurie). DF varied by an order of magnitude in normal (0.04 to 0.48) and obstructed (0.16 to 0.75) of subjects.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3968336

Messina, M S; Smaldone, G C

1985-02-01

388

[Interaction of diazepam and levodropropizine evaluated with quantitative EEG].  

PubMed

The purpose of this clinical trial was to evaluate the presence of possible interactions between Levodropropizine and benzodiazepines (BZ). Experience was performed recording bioccipital quantified EEG in 5 healthy volunteers in normal conditions, after BZ administration and after BZ plus Levodropropizine administration. The slight shifting towards lower frequences in quantified EEG, due to BZ, was not modified by Levodropropizine administration. As results from this experience Levodropropizine seems not to have sinergic action on BZ effect in quantified EEG. PMID:2798991

Arrigo, A; Bejor, M; Beungarbe, D; Cosentina, R

1989-02-01

389

A novel technique for quantitative performance evaluation of wireless LANs  

Microsoft Academic Search

The network performances of two commercial wireless local area networks (WLANs) are measured using a novel technique. Current methods of evaluating the performance of WLANs are largely based on file transfer operations using benchmark tests such as Novell's PERFORM3, AT&T's Read\\/Write, PC Magazine's Lab Series, Smart LAN Performance Test and others. Measurements obtained from these tests must specify the processor

Benny Bing; Regu Subramanian

1998-01-01

390

A quantitative method for visual phantom image quality evaluation  

Microsoft Academic Search

This work presents an image quality evaluation technique for uniform-background target-object phantom images. The Degradation-Comparison-Threshold (DCT) method involves degrading the image quality of a target-containing region with a blocking processing and comparing the resulting image to a similarly degraded target-free region. The threshold degradation needed for 92% correct detection of the target region is the image quality measure of the

Dev P. Chakraborty; Xiong Liu; Michael O'Shea; Lawrence C. Toto

2000-01-01

391

Quantitative evaluation of wrist posture and typing performance: A comparative study of 4 computer keyboards  

SciTech Connect

The present study focuses on an ergonomic evaluation of 4 computer keyboards, based on subjective analyses of operator comfort and on a quantitative analysis of typing performance and wrist posture during typing. The objectives of this study are (1) to quantify differences in the wrist posture and in typing performance when the four different keyboards are used, and (2) to analyze the subjective preferences of the subjects for alternative keyboards compared to the standard flat keyboard with respect to the quantitative measurements.

Burastero, S.

1994-05-01

392

Applying Quantitative Approaches to the Formative Evaluation of Antismoking Campaign Messages  

PubMed Central

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

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

393

Clinical usefulness of quantitative evaluation of visceral fat by ultrasonography  

Microsoft Academic Search

Purpose  The aim of this work was to evaluate the usefulness of a proposed method for visceral fat volume assessment by ultrasonography\\u000a (US) in identifying those at risk of metabolic syndrome, and also to establish the most suitable cutoff level of waist circumference\\u000a for the diagnosis of visceral adiposity.\\u000a \\u000a \\u000a \\u000a Methods  One hundred and fifty-two outpatients with metabolic diseases such as hypertension, diabetes,

Seiji Nakanishi; Bunzo Matsuura; Masashi Hirooka; Teruhisa Ueda; Tetsuji Niiya; Shinya Furukawa; Masanori Abe; Yoichi Hiasa; Yoshikazu Kubo; Morikazu Onji

2007-01-01

394

A quantitative evaluation of two methods for preserving hair samples  

USGS Publications Warehouse

Hair samples are an increasingly important DNA source for wildlife studies, yet optimal storage methods and DNA degradation rates have not been rigorously evaluated. We tested amplification success rates over a one-year storage period for DNA extracted from brown bear (Ursus arctos) hair samples preserved using silica desiccation and -20 ??C freezing. For three nuclear DNA microsatellites, success rates decreased significantly after a six-month time point, regardless of storage method. For a 1000 bp mitochondrial fragment, a similar decrease occurred after a two-week time point. Minimizing delays between collection and DNA extraction will maximize success rates for hair-based noninvasive genetic sampling projects.

Roon, D.A.; Waits, L.P.; Kendall, K.C.

2003-01-01

395

[Integral quantitative evaluation of working conditions in the construction industry].  

PubMed

Present method evaluating the quality of environment (using MAC and MAL) does not enable to assess completely and objectively the work conditions of building industry due to multiple confounding elements. A solution to this complicated problem including the analysis of various correlating elements of the system "human--work conditions--environment" may be encouraged by social norm of morbidity, which is independent on industrial and natural environment. The complete integral assessment enables to see the whole situation and reveal the points at risk. PMID:7921835

Guse?nov, A A

1993-01-01

396

Computerized quantitative evaluation of mammographic accreditation phantom images  

SciTech Connect

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.

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

397

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

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.

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

1984-07-01

398

Evaluating melanoma drug response and therapeutic escape with quantitative proteomics.  

PubMed

The evolution of cancer therapy into complex regimens with multiple drugs requires novel approaches for the development and evaluation of companion biomarkers. Liquid chromatography-multiple reaction monitoring mass spectrometry (LC-MRM) is a versatile platform for biomarker measurement. In this study, we describe the development and use of the LC-MRM platform to study the adaptive signaling responses of melanoma cells to inhibitors of HSP90 (XL888) and MEK (AZD6244). XL888 had good anti-tumor activity against NRAS mutant melanoma cell lines as well as BRAF mutant cells with acquired resistance to BRAF inhibitors both in vitro and in vivo. LC-MRM analysis showed HSP90 inhibition to be associated with decreased expression of multiple receptor tyrosine kinases, modules in the PI3K/AKT/mammalian target of rapamycin pathway, and the MAPK/CDK4 signaling axis in NRAS mutant melanoma cell lines and the inhibition of PI3K/AKT signaling in BRAF mutant melanoma xenografts with acquired vemurafenib resistance. The LC-MRM approach targeting more than 80 cancer signaling proteins was highly sensitive and could be applied to fine needle aspirates from xenografts and clinical melanoma specimens (using 50 ?g of total protein). We further showed MEK inhibition to be associated with signaling through the NF?B and WNT signaling pathways, as well as increased receptor tyrosine kinase expression and activation. Validation studies identified PDGF receptor ? signaling as a potential escape mechanism from MEK inhibition, which could be overcome through combined use of AZD6244 and the PDGF receptor inhibitor, crenolanib. Together, our studies show LC-MRM to have unique value as a platform for the systems level understanding of the molecular mechanisms of drug response and therapeutic escape. This work provides the proof-of-principle for the future development of LC-MRM assays for monitoring drug responses in the clinic. PMID:24760959

Rebecca, Vito W; Wood, Elizabeth; Fedorenko, Inna V; Paraiso, Kim H T; Haarberg, H Eirik; Chen, Yi; Xiang, Yun; Sarnaik, Amod; Gibney, Geoffrey T; Sondak, Vernon K; Koomen, John M; Smalley, Keiran S M

2014-07-01

399

Quantitative Evaluation of Water Deposited By Dew on Monuments  

NASA Astrophysics Data System (ADS)

Samples of White and Green Carrara marble, and three types oflimestone and brick exposed in the field vertically and horizontally were used to evaluate condensationon monuments during clear sky nights. Experiments in a simulation chamber under controlledconditions led to a general equation for the actual amount of water deposited on a surface by dew.This is determined by: How much and for how long the surface temperature falls below the dew point,the moisture content in the air and the ventilation. On clear nights, the condensation on buildingstructures facing the sky may reach some 0.2 kg m-2 (or 0.2 mm), whereas condensation on verticalsurfaces is very small. Computation of the seasonal trend of night-time condensationshowed that the maximum amount of water condensed per night occurs in the autumn, with the moreabundant concentration of moisture in the air. The total amount of water condensed per month isfound to be a maximum in the summer-autumn period. Morning condensationfor the thermal inertia of monuments is also relevant, and has been calculated to reach the same order of magnitude as thenocturnal dew. A detailed analysis of the temperature and mixing ratio profiles near a condensingsurface has shown two different situations. In still air, the two profiles follow an exponentiallaw and the thermal and the concentration layers lie within a few tens of millimetres. Inthe presence of turbulence, the thickness of these two layers is dramatically reduced. In still air, infront of a vertical, chilly surface, the deposition rate of air pollutants by thermophoresis and/orStefan flow is increased by 3 or 4 times in comparison with a horizontal surface. In the presence ofturbulence, the thickness of the thermal and concentration layers was dramatically reduced, makingthese two kinds of deposition much faster.

Camuffo, Dario; Giorio, Roberta

400

Cartilage Repair Surgery: Outcome Evaluation by Using Noninvasive Cartilage Biomarkers Based on Quantitative MRI Techniques?  

PubMed Central

Background. New quantitative magnetic resonance imaging (MRI) techniques are increasingly applied as outcome measures after cartilage repair. Objective. To review the current literature on the use of quantitative MRI biomarkers for evaluation of cartilage repair at the knee and ankle. Methods. Using PubMed literature research, studies on biochemical, quantitative MR imaging of cartilage repair were identified and reviewed. Results. Quantitative MR biomarkers detect early degeneration of articular cartilage, mainly represented by an increasing water content, collagen disruption, and proteoglycan loss. Recently, feasibility of biochemical MR imaging of cartilage repair tissue and surrounding cartilage was demonstrated. Ultrastructural properties of the tissue after different repair procedures resulted in differences in imaging characteristics. T2 mapping, T1rho mapping, delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), and diffusion weighted imaging (DWI) are applicable on most clinical 1.5?T and 3?T MR scanners. Currently, a standard of reference is difficult to define and knowledge is limited concerning correlation of clinical and MR findings. The lack of histological correlations complicates the identification of the exact tissue composition. Conclusions. A multimodal approach combining several quantitative MRI techniques in addition to morphological and clinical evaluation might be promising. Further investigations are required to demonstrate the potential for outcome evaluation after cartilage repair. PMID:24877139

Jungmann, Pia M.; Baum, Thomas; Bauer, Jan S.; Karampinos, Dimitrios C.; Link, Thomas M.; Li, Xiaojuan; Trattnig, Siegfried; Rummeny, Ernst J.; Woertler, Klaus; Welsch, Goetz H.

2014-01-01

401

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

NASA Astrophysics Data System (ADS)

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.

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

2012-07-01

402

Evaluation of reference genes for quantitative RT-PCR in Lolium temulentum under abiotic stress  

Technology Transfer Automated Retrieval System (TEKTRAN)

Lolium temulentum is a valuable model grass species for the study of stress in forage and turf grasses. Gene expression analysis by quantitative real time RT-PCR relies on the use of proper internal standards. The aim of this study was to identify and evaluate reference genes for use in real-time q...

403

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...

404

Evaluation of putative cytoprotective properties of antiulcer drugs using quantitative histological techniques  

Microsoft Academic Search

The capacity for cytoprotection has been claimed for a number of drugs that may have a place in the treatment of peptic ulcer disease. In this study we have used quantitative histological criteria to evaluate the ability of these drugs to be cytoprotective and have compared their effects with that of natural prostaglandin E2 (PG). The standard rat model, with

Paul E. O'Brien; Gary Frydman; Robert Holmes; Cathy Malcontenti; David Phelan

1990-01-01

405

Toward Web-Site Quantitative Evaluation: Defining Quality Characteristics and Attributes.  

ERIC Educational Resources Information Center

This paper identifies World Wide Web site characteristics and attributes and groups them in a hierarchy. The primary goal is to classify the elements that might be part of a quantitative evaluation and comparison process. In order to effectively select quality characteristics, different users' needs and behaviors are considered. Following an…

Olsina, L; Rossi, G.

406

Quantitative Evaluation of Dependence among Outputs in ECOC Classifiers Using Mutual Information Based  

E-print Network

in interpreting the dependence among the outputs as the common information shared among them. Mutual informationQuantitative Evaluation of Dependence among Outputs in ECOC Classifiers Using Mutual Information dependence among the outputs of learning machines can provide us with infor- mation about their nature

Masulli, Francesco

407

Quantitative model for evaluate routing protocols in a vehicular ad hoc networks on highway  

E-print Network

Quantitative model for evaluate routing protocols in a vehicular ad hoc networks on highway Florent management protocols for vehicular Ad Hoc network (VANET), more precisely, to determine the best routing into consideration the network dynamics. Proactive ad hoc protocols have shown strength for static or quasi

Johnen, Colette

408

Qualitative and quantitative evaluation of heart sound reduction from lung sound recordings.  

PubMed

Recursive least squares (RLS) adaptive noise cancellation (ANC) and wavelet transform (WT) ANC have been applied and compared for heart sound (HS) reduction from lung sounds (LS) recordings. Novel processes for quantitative and qualitative evaluation of any method for HS reduction from LS have also been proposed. PMID:16235665

Gnitecki, January; Hossain, Irina; Pasterkamp, Hans; Moussavi, Zahra

2005-10-01

409

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

ERIC Educational Resources Information Center

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,…

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

2014-01-01

410

Quantitative evaluation of skeletal tumours with dynamic FDG PET: SUV in comparison to Patlak analysis  

Microsoft Academic Search

This study was carried out to evaluate bone lesions using fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) and to explore whether dynamic and quantitative PET data may help to differentiate benign lesions from malignant masses. Forty patients with primary bone lesions were studied. The final diagnosis was confirmed by histopathology. A 60-min dynamic FDG PET acquisition was undertaken in all

Hua Wu; Antonia Dimitrakopoulou-Strauss; Thomas O. Heichel; Burkhard Lehner; Ludger Bernd; Volker Ewerbeck; Cyrill Burger; Ludwig G. Strauss

2001-01-01

411

Qualitative and quantitative evaluation of heart sound reduction from lung sound recordings  

Microsoft Academic Search

Recursive least squares (RLS) adaptive noise cancellation (ANC) and wavelet transform (WT) ANC have been applied and compared for heart sound (HS) reduction from lung sounds (LS) recordings. Novel processes for quantitative and qualitative evaluation of any method for HS reduction from LS have also been proposed.

January Gnitecki; Irina Hossain; Hans Pasterkamp; Zahra Moussavi

2005-01-01

412

Quantitative Study of the Value of Research Libraries: A Foundation for the Evaluation of Digital Libraries  

E-print Network

Quantitative Study of the Value of Research Libraries: A Foundation for the Evaluation of Digital Libraries Paul B. Kantor and Tefko Saracevic LIS and Rutgers Distributed Laboratory for Digital Libraries School of Communication, Information and Library Studies Rutgers University, New Brunswick, NJ {kantor

413

Quantitative Evaluation of Liver-Specific Promoters From Retroviral Vectors After In Vivo Transduction of Hepatocytes  

E-print Network

Quantitative Evaluation of Liver-Specific Promoters From Retroviral Vectors After In Vivo of inherited blood diseases such ashemophilia or thrombophi- lia. Although liver-directed retroviral its clinical application, We reasoned that the insertion of liver-specific promoters into retroviral

Ponder, Katherine P.

414

X-ray tomography as a non-destructive tool for evaluating the preservation of primary isotope signatures and mineralogy of Mesozoic fossils  

NASA Astrophysics Data System (ADS)

The stable isotope compositions of carbonate and phosphate components in fossil teeth and bone are widely used to infer information on paleoclimate and the physiology of extinct organisms. Recently the potential for measuring the body temperatures of extinct vertebrates from analyses of 13C-18O bond ordering in fossil teeth has been demonstrated (Eagle et al. 2010). The interpretation of these isotopic signatures relies on an assessment of the resistance of fossil bioapatite to alteration, as diffusion within, and partial recrystallization, or replacement of the original bioapatite will lead to measured compositions that represent mixtures between primary and secondary phases and/or otherwise inaccurate apparent temperatures. X-ray computed tomography (CT) allows 3-D density maps of teeth to be made at micron-scale resolution. Such density maps have the potential to record textural evidence for alteration, recrystallization, or replacement of enamel. Because it is non-destructive, CT can be used prior to stable isotope analysis to identify potentially problematic samples without consuming or damaging scientifically significant specimens. As a test, we have applied CT to tooth fragments containing both dentin and enamel from Late Jurassic sauropods and a Late Cretaceous theropod that yielded a range of clumped isotope temperatures from anomalously high ˜60oC to physiologically plausible ?40oC. This range of temperatures suggests partial, high-temperature modification of some specimens, but possible preservation of primary signals in others. Three-dimensional CT volumes generated using General Electric Phoenix|x-ray CT instruments were compared with visible light and back-scattered electron images of the same samples. The tube-detector combination used for the CT study consisted of a 180 kV nanofocus transmission tube coupled with a 127 micron pixel pitch detector ( ˜3-12? m voxel edges), allowing us to clearly map out alteration zones in high contrast, while reducing edge effects and beam hardening artifacts. CT images of these teeth show a range of replacement textures. One tooth -- thought to be the least altered -- shows only localized positive density anomalies near fractures, while a second -- thought to be highly altered -- contains high-density replacement mineralization. A third tooth -- one suspected of possible partial alteration -- shows a network of rectilinear density anomalies in the enamel similar to 2-D transmitted light and back-scattered electron images. This may represent recrystallization or replacement of the primary bioapatite. Unlike 2-D imaging techniques, 3-D volumes can be used to quickly and easily make quantitative measurements of the volumes of altered and unaltered materials: For example, in the enamel of sample 3, we observe a ratio of high density to low density material of ˜ 3:2.

Santillan, J. D.; Boyce, J. W.; Eagle, R.; Martin, T.; Tuetken, T.; Eiler, J.

2010-12-01

415

Noninvasive, Nondestructive Approaches to Cell Bioenergetics  

NASA Astrophysics Data System (ADS)

To demonstrate the feasibility of using NMR spectra of human limbs and larger animals for continuous, noninvasive, nondestructive evaluation of cell bioenergetics, we have constructed a relatively simple and inexpensive 31P NMR apparatus. This apparatus consists of an 18-cm (7-in.) bore superconducting magnet and appropriate transmit-receive components for Fourier transform NMR. The principal signals observed by this instrument in the tissues are due to phosphocreatine and inorganic phosphate. The apparatus can be used to detect tissue normoxia and hypoxia. The large phosphocreatine/phosphate ratio (>10:1), and the low phosphate signal from normoxic tissue (? 10% of the phosphocreatine signal from brain and human skeletal tissue) make an increased phosphate peak a very sensitive indicator of tissue hypoxia. Direct experiments on the human forearm and leg and the brains of dog and rabbit suggest the applicability of 31P NMR to humans and animals. This method and optical methods can both be used for quantitative determination of oxygen delivery to tissue, function of mitochondria, and the coupling of bioenergetic processes to functional activity in skeletal tissue and brain.

Chance, B.; Eleff, S.; Leigh, J. S.

1980-12-01

416

Non-Destructive Quality Evaluation of Pepper (Capsicum annuum L.) Seeds Using LED-Induced Hyperspectral Reflectance Imaging  

PubMed Central

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

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

2014-01-01

417

J Nondestruct Eval DOI 10.1007/s10921-014-0225-0  

E-print Network

J Nondestruct Eval DOI 10.1007/s10921-014-0225-0 Dynamic Acousto-Elasticity in a Fatigue of Paris VI, UPMC, CNRS, Paris, France Keywords Nondestructive evaluation · Nonlinear ultra- sound-probe meth- ods that have existed in nonlinear acoustics from at least the 123 #12;J Nondestruct Eval 1950s

418

J Nondestruct Eval (2007) 26: 123134 DOI 10.1007/s10921-007-0027-8  

E-print Network

J Nondestruct Eval (2007) 26: 123­134 DOI 10.1007/s10921-007-0027-8 Single Mode Tuning Effects extensive computation, and is not effective for real- time SHM system [6, 7]. #12;124 J Nondestruct Eval-reversal mirror [11] Furthermore, traditional guided wave SHM techniques developed from nondestructive evaluation

Giurgiutiu, Victor

419

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

Federal Register 2010, 2011, 2012, 2013

...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...

2012-07-17

420

Nondestructive examination development and demonstration plan  

SciTech Connect

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.

Weber, J.R.

1991-08-21

421

EDDY CURRENT MODELLING FOR NONDESTRUCTIVE TESTING  

Microsoft Academic Search

Abstract: Eddy ,current nondestructive ,evaluation is widely ,used ,to inspect ,conducting ,materials during manufacture or in service. In this context, modeling is a powerful tool for inspection improvements : it helps probe- coil designers to optimise sensors for each examination requirement, it gives better understanding of the involved physics, it helps operator training and it also increases defect analysis reliability.

G. Pichenot; F. Buvat; V. Maillot; H. Voillaume

422

Nondestructive subharmonic imaging  

Microsoft Academic Search

Ultrasound contrast agent microbubbles are intravascular agents that can be used to estimate blood perfusion. Blood perfusion may be estimated by destroying the bubbles in a vascular bed and observing the refresh of contrast agents back into the vascular bed. Contrast agents can be readily destroyed by traditional imaging techniques. The design of a nondestructive imaging technique is necessary for

J. Chomas; P. Dayton; D. May; K. Ferrara

2002-01-01

423

Spectral nondestructive evaluation—SNDE  

NASA Astrophysics Data System (ADS)

Programmed paint stripping and repainting for commercial and military aircraft inspection consumes a large amount time and money and generates considerable amounts of toxic waste. A technique is required that detects surface cracks and corrosion of metallic aerostructures while leaving the paint coating intact. We have investigated the use of infrared spectral reflectance techniques for seeing through paint coatings to the underlying substrate. Many commercial and milspec primers and topcoats exhibit an optically transparent window in the mid-IR range which permits the extraction of spectral reflectance signatures from as well as allowing imaging of the substrate. Both diffuse reflectance and multispectral IR focal plane imaging is used to successfully detect corrosion and surface morphology of painted metal surfaces.

Di Marzio, D.; McLaughlin, J. S.; Chu, S.; Fonneland, N.; Weir, J.

2001-04-01

424

Cardiac dysfunction in the diabetic rat: quantitative evaluation using high resolution magnetic resonance imaging  

E-print Network

ral ssBioMed CentCardiovascular Diabetology Open AcceOriginal investigation Cardiac dysfunction in the diabetic rat: quantitative evaluation using high resolution magnetic resonance imaging Rajprasad Loganathan1, Mehmet Bilgen2,3, Baraa Al-Hafez2...* - ismirnova@kumc.edu * Corresponding author Abstract Background: Diabetes is a major risk factor for cardiovascular disease. In particular, type 1 diabetes compromises the cardiac function of individuals at a relatively early age due to the protracted...

Loganathan, Rajprasad; Bilgen, Mehmet; Al-Hafez, Baraa; Alenezy, Mohammed D.; Smirnova, Irina V.

2006-04-04

425

Research on quantitative and objective measurement and evaluation for obstacle of limb movement  

Microsoft Academic Search

The obstacle of limb movement caused by brain hurtfuled disease is the patients' most encountered symptom. At present the general measurement and evaluation method is for monitoring the obstacle degree of patient's limb function, which depends on doctor's personal experience and his\\/hers subjective judgement, that is a visual and subjective method; it is not only fuzzy (non-quantitative) but also non-standardised.

Shifu Fan; Hanyuan Jiang; Songshan Xiao; Yanfang Li; Zhendong Sun; Yuchun Zhao; Yingxin Li

1999-01-01

426

Evaluation of a detergent scrub technique for the quantitative culture of Malassezia pachydermatis from canine skin  

Microsoft Academic Search

A detergent scrub technique using wash fluid consisting of 0·075 M phosphate-buffered saline, pH 7·9 containing 0·1 per cent Triton X-100 was evaluated for the quantitative culture of Malassezia pachydermatis from canine skin. Preliminary studies showed that the detergents Triton X-100, Tween 40 and Tween 80 were equally able to disperse suspensions of pure cultures of M pachydermatis, but that

J. M Plummer

1995-01-01

427

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

Microsoft Academic Search

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

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

428

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

PubMed Central

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

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

2013-01-01

429

Quantitative image quality evaluation of an order-statistic filter in x-ray fluoroscopic imaging  

Microsoft Academic Search

The use of x-ray fluoroscopy in complex interventional procedures can result in high patient dose leading to severe skin injuries. Simply reducing exposure degrades image quality. One solution is to acquire images at reduced exposures and digitally filter to reduce noise and restore image quality. We quantitatively evaluated image quality improvement from a bi-directional multi-stage (BMS) median spatio-temporal filter. Improvements

David L. Wilson; Yogesh Srinivas; Francisco J. Sanchez-Marin; Kadri N. Jabri

2000-01-01

430

Development of frequency and phase modulated thermal-wave methodologies for materials non-destructive evaluation and thermophotonic imaging of turbid media  

NASA Astrophysics Data System (ADS)

In frequency-domain photothermal radiometry (FD-PTR) a low-power intensity-modulated optical excitation generates thermal-wave field inside the sample and the subsequent infrared radiation from the sample is analyzed to detect material's inhomogeneities. The non-contact nature of FD-PTR makes it very suitable for non-destructive evaluation of broad range of materials. Moreover, the methodology is based on intrinsic contrast of light absorption which can be used as a diagnostic tool for inspection of malignancy in biological tissues. Nevertheless, the bottom line is that the physics of heat diffusion allows for a highly damped and dispersive propagation of thermal-waves. As a result, the current FD-PTR modalities suffer from limited inspection depth and poor axial/depth resolution. The main objective of this thesis is to show that using alternative types of modulation schemes (such as linear frequency modulation and binary phase coding) and radar matched filter signal processing, one can obtain localized responses from inherently diffuse thermal wave fields. In this thesis, the photothermal responses of turbid, transparent, and opaque media to linear frequency modulated and binary phase coded excitations are analytically derived. Theoretical simulations suggest that matched-filtering in diffusion-wave field acts as constructive interferometry, localizing the energy of the long-duty excitation under a narrow peak and allowing one to construct depth resolved images. The developed technique is the diffusion equivalent of optical coherence tomography and is named thermal coherence tomography. It was found that the narrow-band binary phase coded matched filtering yields optimal depth resolution, while the broad-band linear frequency modulation can be used to quantify material properties through the multi-parameter fitting of the experimental data to the developed theory. Thermophotonic detection of early dental caries is discussed in detail as a potential diagnostic application of the proposed methodologies. The performance of the diagnostic system is verified through a controlled demineralization protocol as well as in teeth with natural caries.

Tabatabaei, Nima

431

Ultrasonic Nondestructive Characterization of Adhesive Bonds  

NASA Technical Reports Server (NTRS)

Adhesives and adhesive joints are widely used in various industrial applications to reduce weight and costs, and to increase reliability. For example, advances in aerospace technology have been made possible, in part, through the use of lightweight materials and weight-saving structural designs. Joints, in particular, have been and continue to be areas in which weight can be trimmed from an airframe through the use of novel attachment techniques. In order to save weight over traditional riveted designs, to avoid the introduction of stress concentrations associated with rivet holes, and to take full advantage of advanced composite materials, engineers and designers have been specifying an ever-increasing number of adhesively bonded joints for use on airframes. Nondestructive characterization for quality control and remaining life prediction has been a key enabling technology for the effective use of adhesive joints. Conventional linear ultrasonic techniques generally can only detect flaws (delamination, cracks, voids, etc) in the joint assembly. However, more important to structural reliability is the bond strength. Although strength, in principle, cannot be measured nondestructively, a slight change in material nonlinearity may indicate the onset of failure. Furthermore, microstructural variations due to aging or under-curing may also cause changes in the third order elastic constants, which are related to the ultrasonic nonlinear parameter of the polymer adhesive. It is therefore reasonable to anticipate a correlation between changes in the ultrasonic nonlinear acoustic parameter and the remaining bond strength. It has been observed that higher harmonics of the fundamental frequency are generated when an ultrasonic wave passes through a nonlinear material. It seems that such nonlinearity can be effectively used to characterize bond strength. Several theories have been developed to model this nonlinear effect. Based on a microscopic description of the nonlinear interface binding force, a quantitative method was presented. Recently, a comparison between the experimental and simulated results based on a similar theoretical model was presented. A through-transmission setup for water immersion mode-converted shear waves was used to analyze the ultrasonic nonlinear parameter of an adhesive bond. In addition, ultrasonic guided waves have been used to analyze adhesive or diffusion bonded joints. In this paper, the ultrasonic nonlinear parameter is used to characterize the curing state of a polymer/aluminum adhesive joint. Ultrasonic through-transmission tests were conducted on samples cured under various conditions. The magnitude of the second order harmonic was measured and the corresponding ultrasonic nonlinear parameter was evaluated. A fairly good correlation between the curing condition and the nonlinear parameter is observed. The results show that the nonlinear parameter might be used as a good indicator of the cure state for adhesive joints.

Qu, Jianmin

1999-01-01

432

Evaluation of an image-based algorithm for quantitative spectral CT applications  

NASA Astrophysics Data System (ADS)

In this paper we describe and evaluate an image-based spectral CT method. Its central formula expresses measured CT data as a spectral integration of the spectral attenuation coefficient multiplied by a LocalWeighting Function (LWF). The LWF represents the local energy weighting in the image domain, taking into account the system and reconstruction properties and the object self attenuation. A generalized image-based formulation of spectral CT algorithms is obtained, with no need for additional corrections of e.g. beam hardening. The iterative procedure called Local Spectral Reconstruction (LSR) yields both the mass attenuation coefficients of the object and a representation of the LWF. The quantitative accuracy and precision of the method is investigated in several applications, including beam hardening correction, attenuation correction for SPECT/CT and PET/CT and a direct identification of spectral attenuation functions using the LWF result is demonstrated. In all applications the ground truth of the objects is reproduced with a quantitative accuracy in the sub-percent to two percent range. An exponential convergence behavior of the iterative procedure is observed, with one to two iteration steps as a good compromise between quantitative accuracy and precision. We conclude that the method can be used to perform image-based spectral CT reconstructions with quantitative accuracy. Existing algorithms benefit from the intrinsic treatment of beam hardening and system properties. Novel algorithms are enabled to directly compare material model functions to spectral measurement data.

Heismann, Björn J.; Balda, Michael

2010-04-01

433

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

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

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

2003-01-01

434

Nondestructive inspection perspectives  

NASA Technical Reports Server (NTRS)

This paper presents ideas for consideration by those concerned with commercial aircraft nondestructive inspection (NDI). The perspective is that of an individual with a background in military aircraft NDI, and important differences are indicated between the commercial NDI and military NDI activities. In particular, it is significantly more expensive to implement some new NDI technology, and therefore, in-depth cost-benifit studies for commercial users are recommended.

Froom, Douglas A.

1992-01-01

435

Quantitative evaluation of the use of actigraphy for neurological and psychiatric disorders.  

PubMed

Quantitative and objective evaluation of disease severity and/or drug effect is necessary in clinical practice. Wearable accelerometers such as an actigraph enable long-term recording of a patient's movement during activities and they can be used for quantitative assessment of symptoms due to various diseases. We reviewed some applications of actigraphy with analytical methods that are sufficiently sensitive and reliable to determine the severity of diseases and disorders such as motor and nonmotor disorders like Parkinson's disease, sleep disorders, depression, behavioral and psychological symptoms of dementia (BPSD) for vascular dementia (VD), seasonal affective disorder (SAD), and stroke, as well as the effects of drugs used to treat them. We believe it is possible to develop analytical methods to assess more neurological or psychopathic disorders using actigraphy records. PMID:25214709

Pan, Weidong; Song, Yu; Kwak, Shin; Yoshida, Sohei; Yamamoto, Yoshiharu

2014-01-01

436

Application of Organosilane Monolayer Template to Quantitative Evaluation of Cancer Cell Adhesive Ability  

NASA Astrophysics Data System (ADS)

The adhesive ability of two human pancreatic cancer cell lines was evaluated using organosilane monolayer templates (OMTs). Using the OMT, the spreading area of adhered cells can be limited, and this enables us to focus on the initial attachment process of adhesion. Moreover, it becomes possible to arrange the cells in an array and to quantitatively evaluate the number of attached cells. The adhesive ability of the cancer cells cultured on the OMT was controlled by adding (-)-epigallocatechin-3-gallate (EGCG), which blocks a receptor that mediates cell adhesion and is overexpressed in cancer cells. Measurement of the relative ability of the cancer cells to attach to the OMT revealed that the ability for attachment decreased with increasing EGCG concentration. The results agreed well with the western blot analysis, indicating that the OMT can potentially be employed to evaluate the adhesive ability of various cancer cells.

Tanii, Takashi; Sasaki, Kosuke; Ichisawa, Kota; Demura, Takanori; Beppu, Yuichi; Vu, Hoan Anh; Thanh Chi, Hoan; Yamamoto, Hideaki; Sato, Yuko

2011-06-01

437

A quantitative evaluation of various deconvolution methods and their applications in the deconvolution of plasma spectra  

NASA Astrophysics Data System (ADS)

A quantitative evaluation of various deconvolution methods and their applications in processing plasma emitted spectra was performed. The iterative deconvolution algorithms evaluated here include Jansson's method, Richardson-Lucy's method, the maximum a posteriori method and Gold's method. The evaluation criteria include minimization of the sum of squared errors and the sum of squared relative error of parameters, and their rate of convergence. After comparing deconvolved results using these methods, it was concluded that Jansson's and Gold's methods were able to provide good profiles that are visually close to the original spectra. Additionally, Gold's method generally gives the best results when considering all the criteria above. The applications to the actual plasma spectra obtained from the EAST tokamak with these methods are also presented in this paper. The deconvolution results with Gold's and Jansson's methods show that the effects of instruments can be satisfactorily eliminated and clear spectra are recovered.

Xiong, Yanwei; Shi, Yuejiang; Li, Yingying; Fu, Jia; Lu, Bo; Zhang, Hongming; Wang, Xiaoguang; Wang, Fudi; Shen, Yongcai

2013-06-01

438

NON-DESTRUCTIVE SOIL CARBON ANALYZER.  

SciTech Connect

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.

WIELOPOLSKI,L.MITRA,S.HENDREY,G.ORION,I.ROGERS,H.TORBERT,A.PRIOR,S.RUNION,B.

2004-02-01

439

Quantitative evaluation of SOCS-induced optical clearing efficiency of skull  

PubMed Central

Background In vivo cortex optical imaging methods for visualization of both structural and functional architecture with high spatial-temporal resolution have shown tremendous advantages in the studies on neurons, glia and microvasculature. To overcome the strong scattering of skull above the cortex, several chronic cranial windows were proposed through craniotomy, but there are some problems. Here, an innovative skull optical clearing solution (SOCS) has been invented to make the skull transparent within 25 min, but SOCS-induced optical clearing efficacy of skull is to be evaluated. Methods Based on the measurements of divergence of beam spot, collimated transmittance of skull, the efficiency of skull optical clearing has been further evaluated quantitatively by comparing with the Monte Carlo simulation. Results The results show that the light beam bandwidth is 5.2±0.3 mm through the initial skull, and reduces to 2.0±0.2 mm trough the treated skull with SOCS; and the calculated scattering coefficient almost decreases to one third after the treatment. Conclusions The quantitative evaluation of SOCS-induced optical clearing efficacy of skull provides an important reference for performing transcranial cortical optical imaging or operation based on skull optical clearing technique.

Zhang, Yang; Zhang, Chao; Zhong, Xiewei

2015-01-01

440

A quantitative method of evaluation of gait under the influence of electrical stimulation in hemiparetic patients.  

PubMed

To improve the procedure of selecting stimulation parameters for the best functional movement, quantitative gait evaluation was investigated. Based on the information obtained by force measuring shoes and a goniometric system, the method consists of computing average values and standard deviations of ground reaction and its point of action, goniometric functions, as well as the ankle joint torque in the sagittal and frontal plane, and their graphic representation. Deviation of the measured variables with respect to the normal gait pattern is the measure of the gait quality. Stimulation parameters were adjusted so that the patient's gait pattern approached normal. PMID:3165202

Kljaji?, M; Krajnik, J; Stanic, U

1988-01-01

441

Development and evaluation of a model-based downscatter compensation method for quantitative I-131 SPECT  

PubMed Central

Purpose: The radionuclide 131I has found widespread use in targeted radionuclide therapy (TRT), partly due to the fact that it emits photons that can be imaged to perform treatment planning or posttherapy dose verification as well as beta rays that are suitable for therapy. In both the treatment planning and dose verification applications, it is necessary to estimate the activity distribution in organs or tumors at several time points. In vivo estimates of the 131I activity distribution at each time point can be obtained from quantitative single-photon emission computed tomography (QSPECT) images and organ activity estimates can be obtained either from QSPECT images or quantification of planar projection data. However, in addition to the photon used for imaging, 131I decay results in emission of a number of other higher-energy photons with significant abundances. These higher-energy photons can scatter in the body, collimator, or detector and be counted in the 364 keV photopeak energy window, resulting in reduced image contrast and degraded quantitative accuracy; these photons are referred to as downscatter. The goal of this study was to develop and evaluate a model-based downscatter compensation method specifically designed for the compensation of high-energy photons emitted by 131I and detected in the imaging energy window. Methods: In the evaluation study, we used a Monte Carlo simulation (MCS) code that had previously been validated for other radionuclides. Thus, in preparation for the evaluation study, we first validated the code for 131I imaging simulation by comparison with experimental data. Next, we assessed the accuracy of the downscatter model by comparing downscatter estimates with MCS results. Finally, we combined the downscatter model with iterative reconstruction-based compensation for attenuation (A) and scatter (S) and the full (D) collimator-detector response of the 364 keV photons to form a comprehensive compensation method. We evaluated this combined method in terms of quantitative accuracy using the realistic 3D NCAT phantom and an activity distribution obtained from patient studies. We compared the accuracy of organ activity estimates in images reconstructed with and without addition of downscatter compensation from projections with and without downscatter contamination. Results: We observed that the proposed method provided substantial improvements in accuracy compared to no downscatter compensation and had accuracies comparable to reconstructions from projections without downscatter contamination. Conclusions: The results demonstrate that the proposed model-based downscatter compensation method is effective and may have a role in quantitative 131I imaging. PMID:21815394

Song, Na; Du, Yong; He, Bin; Frey, Eric C.

2011-01-01

442

Quantitative Evaluation of Voltage-Induced Magnetic Anisotropy Change by Magnetoresistance Measurement  

NASA Astrophysics Data System (ADS)

We investigated the voltage-induced perpendicular magnetic anisotropy change in an epitaxial magnetic tunnel junction (MTJ) with an ultrathin FeCo layer. Tunneling magnetoresistance (TMR) curves were measured under various bias voltage applications for different FeCo thicknesses. Clear changes in the shape of TMR curves were observed depending on the voltage-controlled perpendicular magnetic anisotropy. By evaluating the relative angle of two ferromagnetic layers, we could estimate the anisotropy energy change quantitatively. The realization of voltage-induced anisotropy change in the MTJ structure makes it possible to control the magnetization dynamics, leading to a new area of electric-field-based spintronics devices.

Shiota, Yoichi; Murakami, Shinichi; Bonell, Frédéric; Nozaki, Takayuki; Shinjo, Teruya; Suzuki, Yoshishige

2011-04-01

443

Nondestructive testing with thermography  

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

444

Nondestructive material characterization  

DOEpatents

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.

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

1991-01-01

445

Quantitative evaluation study of four-dimensional gated cardiac SPECT reconstruction †  

PubMed Central

In practice gated cardiac SPECT images suffer from a number of degrading factors, including distance-dependent blur, attenuation, scatter, and increased noise due to gating. Recently we proposed a motion-compensated approach for four-dimensional (4D) reconstruction for gated cardiac SPECT, and demonstrated that use of motion-compensated temporal smoothing could be effective for suppressing the increased noise due to lowered counts in individual gates. In this work we further develop this motion-compensated 4D approach by also taking into account attenuation and scatter in the reconstruction process, which are two major degrading factors in SPECT data. In our experiments we conducted a thorough quantitative evaluation of the proposed 4D method using Monte Carlo simulated SPECT imaging based on the 4D NURBS-based cardiac-torso (NCAT) phantom. In particular we evaluated the accuracy of the reconstructed left ventricular myocardium using a number of quantitative measures including regional bias-variance analyses and wall intensity uniformity. The quantitative results demonstrate that use of motion-compensated 4D reconstruction can improve the accuracy of the reconstructed myocardium, which in turn can improve the detectability of perfusion defects. Moreover, our results reveal that while traditional spatial smoothing could be beneficial, its merit would become diminished with the use of motion-compensated temporal regularization. As a preliminary demonstration, we also tested our 4D approach on patient data. The reconstructed images from both simulated and patient data demonstrated that our 4D method can improve the definition of the LV wall. PMID:19724094

Jin, Mingwu; Yang, Yongyi; Niu, Xiaofeng; Marin, Thibault; Brankov, Jovan G.; Feng, Bing; Pretorius, P. Hendrik; King, Michael A.; Wernick, Miles N.

2013-01-01

446

29 CFR 1919.78 - Nondestructive examinations.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Nondestructive examinations. 1919.78 Section...Material Handling Devices § 1919.78 Nondestructive examinations. (a) Wherever...electronic, ultrasonic, or other nondestructive methods may be carried out,...

2012-07-01

447

29 CFR 1919.78 - Nondestructive examinations.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Nondestructive examinations. 1919.78 Section...Material Handling Devices § 1919.78 Nondestructive examinations. (a) Wherever...electronic, ultrasonic, or other nondestructive methods may be carried out,...

2013-07-01

448

49 CFR 192.243 - Nondestructive testing.  

...2014-10-01 2014-10-01 false Nondestructive testing. 192.243 Section 192.243...Welding of Steel in Pipelines § 192.243 Nondestructive testing. (a) Nondestructive testing of welds must be performed...

2014-10-01

449

49 CFR 192.243 - Nondestructive testing.  

Code of Federal Regulations, 2013 CFR

...Nondestructive testing. (a) Nondestructive testing of welds must be performed by any process, other than...indicate defects that may affect the integrity of the weld. (b) Nondestructive testing of welds must be performed: (1) In accordance...

2013-10-01

450

A computerized semi-automatic evaluation system for quantitation of electroimmunoassays.  

PubMed

A fast and accurate evaluation system for quantitation of plasma proteins from electroimmunoassay plates is described. The protein concentration is determined from the height of its stained antigen-antibody precipitate by means of a coordinate digitizer connected to a COMPUCORP 445 minicomputer. The plasma protein concentration is calculated from the equation of the best second-order least square regression of data from a standard dilution curve. The values from one type of protein analysis can either be stored on a discette for future examination or printed out each day in a tabular form on a typewriter. A double evaluation of plasma concentrations from plates of two different proteins showed a coefficient of variation (CV) better than 4.5%. A correlation between values obtained by this technique and those obtained by the manual reading procedure has also been done. The correlation coefficient varied between 0.95 and 0.99 depending on the type of protein. PMID:523957

Nilsson, B

1979-02-01

451

Assessing the Expected Impact of Global Health Treaties: Evidence From 90 Quantitative Evaluations  

PubMed Central

We assessed what impact can be expected from global health treaties on the basis of 90 quantitative evaluations of existing treaties on trade, finance, human rights, conflict, and the environment. It appears treaties consistently succeed in shaping economic matters and consistently fail in achieving social progress. There are at least 3 differences between these domains that point to design characteristics that new global health treaties can incorporate to achieve positive impact: (1) incentives for those with power to act on them; (2) institutions designed to bring edicts into effect; and (3) interests advocating their negotiation, adoption, ratification, and domestic implementation. Experimental and quasiexperimental evaluations of treaties would provide more information about what can be expected from this type of global intervention. PMID:25393196

Røttingen, John-Arne

2015-01-01