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1

Quantitative nondestructive evaluation of materials and structures  

NASA Technical Reports Server (NTRS)

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

Smith, Barry T.

1991-01-01

2

The Nuclear Renaissance — Implications on Quantitative Nondestructive Evaluations  

NASA Astrophysics Data System (ADS)

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

Matzie, Regis A.

2007-03-01

3

Dual-band infrared thermography for quantitative nondestructive evaluation  

SciTech Connect

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

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

1993-04-01

4

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

5

Nondestructive evaluation  

Microsoft Academic Search

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

1997-01-01

6

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

SciTech Connect

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

Not Available

1991-01-01

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

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

9

QUANTITATIVE NON-DESTRUCTIVE EVALUATION (QNDE) OF THE ELASTIC MODULI OF POROUS TIAL ALLOYS  

SciTech Connect

The elastic moduli of {gamma}-TiA1 were studied in porous samples consolidated by various techniques e.g. cold isostatic pressing (CIP), pressure-less sintering, or hot isostatic pressing (HIP). Porosity linearly affects the dynamic elastic moduli of samples. The results indicate that the sound wave velocities and the elastic moduli affected by the processing route and depend not only on the attained density but also on the consolidation temperature. In this paper we show that there is linear correlation between the shear and the longitudinal sound velocities in porous TiA1. This opens the way to use a single sound velocity as a tool for quantitative non-destructive evaluation (QNDE) of porous TiA1 alloys. Here we demonstrate the applicability of an equation derived from the elastic theory and used previously for porous cubic metals.

Yeheskel, O. [NRCN, PO Box 9001, Beer Sheva, 84190 (Israel)

2008-02-28

10

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

11

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

12

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

13

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

NASA Astrophysics Data System (ADS)

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

Weischedel, Herbert R.; Hoehle, Hans-Werner

1995-05-01

14

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

Miller, James G.

1997-01-01

15

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

NASA Technical Reports Server (NTRS)

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

Miller, J. G.

1984-01-01

16

Advances in nondestructive evaluation technology  

NASA Technical Reports Server (NTRS)

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

Heyman, J. S.

1982-01-01

17

Quantitative Non-Destructive Evaluation Using Laser-Generated Ultrasonic Pulses.  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. The work presented here utilises features of laser generated ultrasound for the detection of defects in solids. Ultrasound is generated non-contactively by this method and likewise many of the detection devices used do not require direct coupling to the test pieces, thus acoustic pulses with high frequency components are able to be produced and monitored on a range of samples. Steel samples coated with between 3 and 7mm of plasma-transferred arc depositions are examined for bond quality via measurements of attenuation caused by porosity in the coatings, found to be related to weld current. Surface breaking cracks, (of depth <3mm), in such claddings are quantitatively detected by a method which utilises Rayleigh pulses. A two sided automated scanning system is described which examines samples for subsurface defects. Results from the examinations of a dural test piece, plasma sprayed steel bars and carbon fibre composite samples are presented. Resolution of defects is shown to be within 0.5mm for a 1mm thick section of the composite material. A second scanning technique, requiring access to only one sample face, is presented which employs an interferometer for detection and is thus a truly remote system. Laminar flaws are modelled using flat-bottomed holes, the dimensions of which are measured using the resonance of the bodies. A theoretical investigation using various boundary conditions suggests possible applications for quantitative NDE of structures with well defined natural vibration frequencies. The propagation of acoustic transients in plates is also examined. Possible future work concerning laser/ultrasonic NDE is discussed.

Crosbie, Ross Andrew

18

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

19

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

20

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

Miller, James G.

1994-01-01

21

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

22

Nondestructive Evaluation of Pavements Ultrasonic  

E-print Network

Nondestructive Evaluation of Pavements Ð Ultrasonic Tomography Kyle Hoegh, Graduate Student Dr. Lev:// pavementndt.weebly.com #12;Outline ·! Ultrasonic Tomography Overview ·! Georgia Example ·! MnROAD ­!Joint.weebly.com #12;Ultrasonic Methods: Pros and Cons ·! Advantages ­! Multiple applications ·! Thickness

Minnesota, University of

23

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

24

Nondestructive evaluation of advanced ceramics  

NASA Technical Reports Server (NTRS)

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

Klima, Stanley J.; Kautz, Harold E.

1988-01-01

25

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

26

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

27

Holographic nondestructive evaluation: status and future  

Microsoft Academic Search

The results and conclusions of an extensive review of the literature and practice of holographic nondestructive evaluation (NDE) are reported. Although this technique has several technically unique features, and has been shown to be a feasible nondestructive testing technique in a very large number of laboratory investigations, its commercial application is rare. A counter example is its prevalent use in

C. M. Birnbaum; C. M. Vest

1983-01-01

28

Nondestructive quantitative stress characterization of wire rope and steel cables  

Microsoft Academic Search

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.

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

1998-01-01

29

Review of holographic nondestruction evaluation at Lawrence Livermore National Laboratory  

SciTech Connect

At Lawrence Livermore National Laboratory two holographic facilities have been established for the technology transfer of holographic interferometry. This report is a review of the principles of holographic interferometry (HI) and the application of this technique to nondestructive evaluation. Simplified quantitative analysis using a coincident viewing and illumination optical arrangement are described.

Boyd, D.M.

1983-01-01

30

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

31

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

32

Holographic nondestructive evaluation: status and future  

SciTech Connect

The results and conclusions of an extensive review of the literature and practice of holographic nondestructive evaluation (NDE) are reported. Although this technique has several technically unique features, and has been shown to be a feasible nondestructive testing technique in a very large number of laboratory investigations, its commercial application is rare. A counter example is its prevalent use in testing of aircraft and heavy equipment tires. The status of the technique is reviewed, recent and potential technical advances are enumerated, and suggestions of activities which would enable full realization and evaluation of the potential of holographic NDE in the future are made.

Birnbaum, C.M.; Vest, C.M.

1983-01-01

33

Non-destructive evaluation of composite materials using ultrasound  

NASA Technical Reports Server (NTRS)

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

Miller, J. G.

1984-01-01

34

Nondestructive evaluation of steam traps  

NASA Astrophysics Data System (ADS)

Many thermographers have touted infrared thermography as an effective maintenance tool for evaluating steam traps for years. However, several investigators have raised questions about thermal measurement's effectiveness in this application. This paper explores and compares infrared thermography and ultrasonic detection methods for steam trap testing and provides guidelines for a successful trap survey.

Orlove, Gary L.

1999-03-01

35

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

36

Development of instrumentation for magnetic nondestructive evaluation  

SciTech Connect

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

Hariharan, S.

1991-09-23

37

A review of holographic nondestruction evaluation at Lawrence Livermore National Laboratory  

SciTech Connect

Holographic nondestructive evaluation at Lawrence Livermore National Laboratory has been developed for simplified, repeatable and quantitative analysis. The objective of the development work has been to fulfill the needs of the programs for reliable holographic testing. As part of this work two laser holography laboratories have been equipped for application and development of holographic interferometry. The coincident viewing and illumination optical arrangement permits quantitative determination of displacement and strain from holographic interferograms. This work resulted in the development of holographic fringe data acquisition and analysis system for quantitative calculations. Future work will include further development of the quantitative analysis methods, as well as speckle interferometry techniques and pulsed holographic capabilities. The Nondestructive Evaluation Section's goal is to provide a means of technology transfer for materials evaluation. Holographic interferometry is one of the techniques being developed for the nondestructive evaluation of materials.

Boyd, D.M.

1983-01-01

38

NONDESTRUCTIVE EVALUATION OF CERAMIC CANDLE FILTERS  

SciTech Connect

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

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

1999-09-01

39

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

40

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

41

Review of progress in quantitative nondestructive evaluation. Vol. 11A; Proceedings of the 18th Annual Review, Bowdoin College, Brunswick, ME, July 28-Aug. 2, 1991  

SciTech Connect

The present volume discusses such topics in quantitative NDE as elastic wave scattering and propagation, eddy currents, X-ray and computed radiography, thermal NDE techniques, optical NDE, developing electromagnetic NDE methods, laser ultrasonics, magnetic resonance imaging, neural networks, imaging and inversion techniques, signal processing, acoustic and ultrasonic sensors, fiber-optic sensors, eddy-current arrays and sensors, corrosion-sensing instruments, and NDE standards. Attention is given to ultrasonic scattering from anisotropic shells, surface-wave propagation in composite laminates, eddy-current testing of carbon-carbon composites, monochromatic X-ray beams for NDT, flying laser spot thermal-wave IR imaging, pulsed lasers for ultrasonic NDE, NMR of advanced composites, and ultrasonic synthetic-aperture holographic imaging.

Thompson, D.O.; Chimenti, D.E.

1992-01-01

42

Nondestructive Evaluation of Reactive Powder Concrete  

NASA Astrophysics Data System (ADS)

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

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

2004-02-01

43

A review of issues and strategies in nondestructive evaluation of fiber reinforced structural composites  

NASA Technical Reports Server (NTRS)

Techniques for quantitative assessment of the mechanical strength and integrity of fiber composites during manufacture and service and following repair operations are presented. Problems and approaches are discussed relative to acceptance criteria, calibrating standards, and methods for nondestructive evaluation of composites in strength-critical applications. Acousto-ultrasonic techniques provide the methods of choice in this area.

Vary, A.

1979-01-01

44

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

E-print Network

NONDESTRUCTIVE DAMAGE EVALUATION OF ELECTRO-MECHANICAL COMPONENTS USING A HYBRID, COMPUTATIONAL AND EXPERIMENTAL, APPROACH C. FURLONG, R. J. PRYPUTNIEWICZ CHSLT ­ Center for Holographic Studies and Laser micro. This, in turn, indicates a need for effective quantitative testing methodologies. In this paper

Furlong, Cosme

45

A review of holographic nondestruction evaluation at Lawrence Livermore National Laboratory  

Microsoft Academic Search

Holographic nondestructive evaluation at Lawrence Livermore National Laboratory has been developed for simplified, repeatable and quantitative analysis. The objective of the development work has been to fulfill the needs of the programs for reliable holographic testing. As part of this work two laser holography laboratories have been equipped for application and development of holographic interferometry. The coincident viewing and illumination

1983-01-01

46

Nondestructive evaluation of composite materials - A design philosophy  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

47

Nondestructive Evaluation of Foam Sidewalls in Super Tiger.  

National Technical Information Service (NTIS)

A nondestructive evaluation technique has been developed for determining the locations of anomalies in the foam sidewalls of overpack-type packagings used for the shipment of radioactive materials. This technique involves heating the interior walls of the...

W. L. Uncapher, M. L. Apple

1988-01-01

48

A new technique for ultrasonic nondestructive evaluation of adhesive joints  

E-print Network

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

Hanneman, Susan Elisabeth

2012-06-07

49

Cryogenic Storage Tank Non-Destructive Evaluation  

NASA Technical Reports Server (NTRS)

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

Arens, Ellen

2010-01-01

50

Microwave nondestructive evaluation of thick sandwich composites  

SciTech Connect

Two microwave nondestructive testing techniques were used to inspect thick, stratified sandwich composites consisting of fiberglass epoxy laminates, foam and honeycomb constituents. Several different defects were embedded in these samples during their production. Each technique relies on the measurement of the reflected microwave energy from the composite samples using an open-ended rectangular waveguide as the inspection probe. The experiments were done at different frequencies and standoff distances based on the results of measurement parameter optimization conducted for each separate defect. The results of measurement parameter optimization conducted for each separate defect. The results of these measurements (presented in image formats) provide impressive detailed information about each defect, such as the raised edges associated with the manufacturing of the delaminations, the shape of the indentations caused by the impact fatigue defects, and surface skin fiber bundle orientations. As expected, higher frequencies provided better spatial resolutions. The importance of optimization as it pertains to successful defect detection and characterization was demonstrated both experimentally and theoretically. The results of this study clearly demonstrate the potential of microwaves as non-destructive tools for inspecting thick composite sandwich structures.

Ganchev, S.I.; Runser, R.J.; Qaddoumi, N.; Ranu, E. [Colorado State Univ., Ft. Collins, CO (United States); Carriveau, G. [Nondestructive Testing Information Analysis Center, Austin, TX (United States)

1995-04-01

51

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

52

Nondestructive Evaluation of Metal Fatigue Using Nonlinear Acoustics  

NASA Astrophysics Data System (ADS)

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 and 410 Cb stainless steel 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.

2009-03-01

53

Nondestructive evaluation of electron-beam braze joins  

SciTech Connect

A nondestructive evaluation (NDE) program has been carried out using holographic interferometry, microradiography, and eddy current testing for the inspection of electron beam braze joining of dissimilar metals. Stainless steel tubing was joined to a gold-copper disk using a Cusil (copper/silver) brazing alloy. Holographic interferometry provided an indirect measure of strength by detecting the plastic deformation occurring as a result of applying a stress. Microradiography with the aid of computer graphics displays provided a means of measuring braze penetration into the stainless steel tube. Correlation of results with metallographic examination and microhardness measurements show that holography and microradiography each provide quantitative braze quality rankings. Each method correctly identified variations in braze quality independent of electron beam power (the only processing variable in sample fabrication). Eddy current results were consistent with the other NDE methods but appear to be based on variation in surface topography rather than electrical conductivity. The usefulness of the eddy current method for this problem is questionable due to its sensitivity to the small, complex test piece geometry.

Boyd, D.M.; Shackelford, J.F.; Maxfield, B.W.; Taylor, G.M.

1981-08-18

54

Nondestructive evaluation of compacted clayey soils  

NASA Astrophysics Data System (ADS)

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

Inci, Gokhan

55

Nondestructive evaluation of electron-beam braze joins  

Microsoft Academic Search

A nondestructive evaluation (NDE) program has been carried out using holographic interferometry, microradiography, and eddy current testing for the inspection of electron beam braze joining of dissimilar metals. Stainless steel tubing was joined to a gold-copper disk using a Cusil (copper\\/silver) brazing alloy. Holographic interferometry provided an indirect measure of strength by detecting the plastic deformation occurring as a result

D. M. Boyd; J. F. Shackelford; B. W. Maxfield; G. M. Taylor

1981-01-01

56

Evaluation of methods for nondestructive testing of brazed joints  

NASA Technical Reports Server (NTRS)

Evaluation of nondestructive methods of testing brazed joints reveals that ultrasonic testing is effective in the detection of nonbonds in diffusion bonded samples. Radiography provides excellent resolutions of void or inclusion defects, and the neutron radiographic technique shows particular advantage for brazing materials containing cadmium.

Kanno, A.

1968-01-01

57

Nondestructive evaluation using dipole model analysis with a scan type magnetic camera  

NASA Astrophysics Data System (ADS)

Large structures such as nuclear power, thermal power, chemical and petroleum refining plants are drawing interest with regard to the economic aspect of extending component life in respect to the poor environment created by high pressure, high temperature, and fatigue, securing safety from corrosion and exceeding their designated life span. Therefore, technology that accurately calculates and predicts degradation and defects of aging materials is extremely important. Among different methods available, nondestructive testing using magnetic methods is effective in predicting and evaluating defects on the surface of or surrounding ferromagnetic structures. It is important to estimate the distribution of magnetic field intensity for applicable magnetic methods relating to industrial nondestructive evaluation. A magnetic camera provides distribution of a quantitative magnetic field with a homogeneous lift-off and spatial resolution. It is possible to interpret the distribution of magnetic field when the dipole model was introduced. This study proposed an algorithm for nondestructive evaluation using dipole model analysis with a scan type magnetic camera. The numerical and experimental considerations of the quantitative evaluation of several sizes and shapes of cracks using magnetic field images of the magnetic camera were examined.

Lee, Jinyi; Hwang, Jiseong

2005-12-01

58

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

59

Nondestructive Evaluation of Ceramic Candle Filters Using Vibration Response  

SciTech Connect

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

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

1997-07-01

60

Large area terahertz imaging and non-destructive evaluation applications  

Microsoft Academic Search

Abstract: Terahertz (THz) imaging,is being adopted for non-destructive evaluation (NDE) applications in aerospace and other government,and industrial settings [1-3]. NASA is currently employing ,THz reflection NDE to examine ,the space shuttle external tank sprayed on foam insulation (SOFI) for voids and disbonds. Homeland security applications such as the inspection of personnel[2], the detection of concealed explosives[2], biological agents, chemical weapons,

David Zimdars; Jeffrey S. White; G. stuk; A. chernovsky; G. Fichter; S. Williamson

2006-01-01

61

Development of nondestructive evaluation methods for ceramic coatings  

Microsoft Academic Search

Various nondestructive evaluation (NDE) technologies are being developed to advance the knowledge of ceramic coatings for components in the hot gas-path of advanced, low-emission gas-fired turbine engines. The ceramic coating systems being studied by NDE include thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs). TBCs are under development for vanes, blades and combustor liners to allow hotter gas path

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

2007-01-01

62

Nondestructive Evaluation of the VSC-17 Cask  

SciTech Connect

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

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

2006-01-01

63

Nondestructive Damage Evaluation in Ceramic Matrix Composites for Aerospace Applications  

PubMed Central

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

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

2013-01-01

64

Nondestructive damage evaluation in ceramic matrix composites for aerospace applications.  

PubMed

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

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

2013-01-01

65

A versatile nondestructive evaluation imaging workstation  

NASA Technical Reports Server (NTRS)

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

Chern, E. James; Butler, David W.

1994-01-01

66

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

67

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

68

Nondestructive evaluation of plasma-sprayed thermal barrier coatings  

SciTech Connect

Acoustic emission has been used as a nondestructive evaluation technique to examine the thermal shock response of thermal barrier coatings. In this study, samples of partially stabilized zirconia powder were sprayed and acoustic emission (AE) data were taken in a series of thermal shock tests in an effort to correlate AE with a given failure mechanism. Microstructural evidence was examined using parallel beam x-ray diffraction and optical microscopy. The AE data are discussed in terms of cumulative amplitude distributions and the use of this technique to characterize fracture events.

Andrews, D.J.; Taylor, J.A.T. [Alfred Univ., NY (United States). New York State Coll. of Ceramics

1997-10-01

69

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

70

Nondestructive Degradation Evaluation of Ceramic Candle Filters Using Vibration Signatures  

SciTech Connect

The structural integrity of ceramic candle filters is a key element for hot gas cleanup systems, They protect the heat exchanger and gas turbine components from getting clogged and also prevent erosion. Ceramic candle filters used in the recent demonstration plant have experienced degradation and fracturing. Preliminary examination of these ceramic filters indicated that damage of the filters may have resulted from strength degradation at consistent high temperature operation, thermal transient events, excessive ash accumulation and bridging and pulse cleaning. The ceramic candle filter is a slender structure made of layers of porous materials. The structure has high acoustic attenuation which has greatly limited the conventional ultrasonic detection capability. In general, stiffness reduction of a structure will cause the change of the modal parameters of the structure. This study proposes a nondestructive approach for evaluating the structural properties of the ceramic filters using dynamic characterization method. The vibration signatures of the ceramic filters at different degradation levels are established using transient impact-response technique. Results from this study indicate that the vibration signatures of the filters can be used as an index to quantify the darnage condition of the filters. The results also indicate the feasibility of using the vibration mode shapes to predict the damage location. The application of this study can be implemented to develop a nondestructive evaluation method for future in-situ inspection of the ceramic filters.

Chen, R.H.L.; Parthasarathy, B. [Department of Civil and Environmental Engineering, West Virginia Univ., Morgantown, WV (United States)

1996-12-31

71

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

72

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

SciTech Connect

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

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

1986-01-01

73

Nerva fuel nondestructive evaluation and characterization equipment and facilities  

NASA Astrophysics Data System (ADS)

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

Caputo, Anthony J.

1993-01-01

74

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

75

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

76

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

77

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

78

Quantitative nondestructive electronic and magnetic property assessment of heat treated grade p91 steel  

NASA Astrophysics Data System (ADS)

Structural steels experience aging from fatigue, creep and corrosion. Prolonged high temperature service accelerates creep and stress-corrosion cracking. Microstructural degradation of structural steels is a serious problem that limits the integrity of high-temperature parts in power plants. Some power plants that utilize fossil fuels have experienced lifecycle issues with heat-treated steel alloys that have experienced progressive damage over time. A nondestructive technique for the evaluation of the microstructure of key structural materials and the prediction of lifecycle has been the focus of extensive research for many years. Advanced nondestructive wave assessment techniques are being developed using electronic and magnetic perturbation analysis. These methods are applied to ferrous materials to determine whether a designed heat-treatment provides an acceptable microstructure offering specific set of required properties for the full service life of the component. The methods used in this research include impedance spectroscopy and hysteresis measurement as preliminary assessment methods and hysteresis frequency analysis and Barkhausen noise measurement as secondary assessment methods.

Meir, Shai Shmuel

79

Nondestructive evaluation of weld defects by infrared thermography  

SciTech Connect

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

Satonaka, Shinobu; Ohba, Hiroyasu; Shinozaki, Kenya [Kumamoto Univ. (Japan). Dept. of Mechanical Engineering

1995-12-31

80

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

81

Nondestructive evaluation of ceramic candle filter with various boundary conditions  

SciTech Connect

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

Chen, H.L.; Kiriakidis, A.C. [West Virginia University, Morgantown, WV (United States). Dept. of Civil & Environmental Engineering

2005-06-01

82

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

83

Nondestructive methods for quality evaluation of livestock products  

Microsoft Academic Search

The muscles derived from livestock are highly perishable. Rapid and nondestructive methods are essential for quality assurance\\u000a of such products. Potential nondestructive methods, which can supplement or replace many of traditional time consuming destructive\\u000a methods, include colour and computer image analysis, NIR spectroscopy, NMRI, electronic nose, ultrasound, X-ray imaging and\\u000a biosensors. These methods are briefly described and the research work

K. Narsaiah; Shyam N. Jha

84

Proceedings of the fifteenth symposium on nondestructive evaluation  

SciTech Connect

This book presents the papers given at a symposium on nondestructive testing. Topics considered at the symposium included the acoustical holographic Siamese image technique for imaging radial cracks in reactor piping, a simulated model for the reliability of ultrasonic inspection, x-ray computed tomography, through-transmission ultrasound, the role of laser technology in materials processing and nondestructive testing, and a computer controlled array of ultrasonic transducers for fast inspection of steel pipes.

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

1985-01-01

85

Development of nondestructive evaluation methods for hot gas filters.  

SciTech Connect

Rigid ceramic hot gas candle filters are currently under development for high-temperature hot gas particulate cleanup in advanced coal-based power systems. The ceramic materials for these filters include monolithics (usually non-oxides), oxide and non-oxide fiber-reinforced composites, and recrystallized silicon carbide. A concern of end users in using these types of filters, where over 3000 may be used in a single installation, is the lack of a data base on which to base decisions for reusing, replacing or predicting remaining life during plant shutdowns. One method to improve confidence of usage is to develop nondestructive evaluation (NDE) technology to provide surveillance methods for determination of the extent of damage or of life-limiting characteristics such as thermal fatigue, oxidation, damage from ash bridging such as localized cracking, damage from local burning, and elongation at elevated temperatures. Although in situ NDE methods would be desirable in order to avoid disassembly of the candle filter vessels, the possible presence of filter cakes and/or ash bridging, and the state of current NDE technology prevent this. Thus, off-line NDE methods, if demonstrated to be reliable, fast and cost effective, could be a significant step forward in developing confidence in utilization of rigid ceramic hot gas filters. Recently, NDE methods have been developed which show promise of providing information to build this confidence. Acousto-ultrasound, a totally nondestructive method, together with advanced digital signal processing, has been demonstrated to provide excellent correlation with remaining strength on new, as-produced filters, and for detecting damage in some monolithic filters when removed from service. Thermal imaging, with digital signal processing for determining through-wall thermal diffusivity, has also been demonstrated to correlate with remaining strength in both new (as-received) and in-service filters. Impact acoustic resonance using a scanning laser vibrometer has been demonstrated to allow detection of changes in frequency which may be correlated to remaining strength. These methods have been shown to be applicable to clay-bonded SiC filters, recrystallized SiC filters, CVI-SiC composite filters and oxide composite filters. Other NDE methods under development include: (a) fast, high spatial-resolution X-ray imaging for detecting density variations and dimensional changes; (b) air-coupled ultrasonic methods for determining through-thickness compositional variations; and (c) acoustic emission technology with mechanical loading for detecting localized bulk damage.

Ellingson, W. A.; Koehl, E. R.; Sun, J. G.; Deemer, C.; Lee, H.; Spohnholtz, T.; Energy Technology

1999-01-01

86

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

87

A calibration procedure for sonic infrared nondestructive evaluation  

SciTech Connect

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

Morbidini, M.; Cawley, P. [Department of Mechanical Engineering, UK Research Centre in NDE, Imperial College, London SW7 2AZ (United Kingdom)

2009-07-15

88

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

89

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

90

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

91

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

2012-06-07

92

Technologies for Nondestructive Evaluation of Surfaces and Thin Coatings  

NASA Technical Reports Server (NTRS)

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

1999-01-01

93

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

94

Non-destructive evaluation of TBC by electrochemical impedance spectroscopy  

NASA Astrophysics Data System (ADS)

The objectives of this work focus on studying the feasibility of developing electrochemical impedance spectroscopy as an NDE methodology for quality assurance and post exposure inspection of TBC. Principally air plasma sprayed TBC was investigated while APS dense vertically cracked TBC and electron beam physical vapor deposition sprayed TBC were also studied using EIS. It has been found that EIS has a great promise in TBC quality assurance and post-exposure assessment. In the quality evaluation, EIS can detect TBC topcoat thickness, porosity, and kinds of defects (pore shape, cracks, or delamination). The TBC topcoat thickness shows a linear relationship with ceramic resistance. The TBC porosity has a linear relationship with ceramic capacitance. The kinds of defects in TBC topcoat can be assessed by the value of pore resistance. In the post-exposure inspection, EIS can monitor the evolution of defects in the topcoat, porosity, the growth of TGO and thermal conductivity of TBC. There is an exponential relationship between thermal conductivity and electrochemical impedance or a logarithmic relationship between thermal conductivity and electrochemical conductance. Investigation on thermal conductivity of TBC showed the specific heat or thermal conductivity of TBC has a logarithmic relationship with temperature, respectively. Exposure temperature and time are two important factors for an increase in thermal conductivity. The higher temperature and longer the exposure, the greater increase the thermal conductivity. High temperature exposure of TBC results in phase transformations, t-ZrO2 ? m-ZrO2 and t-ZrO2 ? c-ZrO2 and evolution of defect (ceramic sintering). Both the phase transformations and the sintering cause an increase in thermal conductivity. However, it has been found the phase transformations are only a conservative factor while the sintering is a substantial reason for an increase in thermal conductivity. A failure mode of TBC due to sintering was suggested. An alternative electrolyte (trifluoroacetic acid) was investigated using EIS in order to be used as compatible or friendly solution to TBC. A similar characteristic EIS result was found using the alternative electrolyte compared with the commonly used electrolyte [Fe(CN)6]-3/[Fe(CN) 6]-4 in this work. It has indicated that a friendly electrolyte be viable for EIS technique to be used for non-destructive evaluation of TBC. Visualization of a flexible probe for EIS field detection has also been designed. (Abstract shortened by UMI.)

Zhang, Jianqi

95

Development of techniques and instrumentation for the nondestructive evaluation of multi-layer insulation  

NASA Technical Reports Server (NTRS)

The development of techniques and instrumentation suitable for the nondestructive evaluation of purged multilayer insulation prior to and after a shuttle orbiter flight is discussed. These techniques are desirable because of the possibility that corrosion, compression, or tearing of the insulation will degrade the performance of the insulation during subsequent flights. A second objective was the application of the developed technology to the evaluation of other insulation types. Three nondestructive evaluation techniques, electromagnetic, thermal, and acoustic were selected for evaluation. The results of evaluation of each technique are described.

1972-01-01

96

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

97

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

98

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

99

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

100

Nondestructive and quantitative characterization of TRU and LLW mixed-waste using active and passive gamma-ray spectrometry and computed tomography  

Microsoft Academic Search

The technology being proposed by LLNL is an Active and Passive Computed Tomography (A P CT) Drum Scanner for contact-handled (CH) wastes. It combines the advantages offered by two well-developed nondestructive assay technologies: gamma-ray spectrometry and computed tomography (CT). Coupled together, these two technologies offer to nondestructively and quantitatively characterize mixed- wastes forms. Gamma-ray spectroscopy uses one or more external

D. C. Camp; H. E. Martz

1991-01-01

101

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

PubMed

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

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

2014-08-01

102

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

103

EVALUATION OF NON-DESTRUCTIVE METHODS FOR ASSESSING STIFFNESS OF DOUGLAS FIR TREES  

Microsoft Academic Search

Identification and selection of superior trees in forest management and breeding programmes provide a means to improve the properties and value of future wood products. Non-destructive stiffness assessment of standing trees enables selection of individuals for their stiffness, and so the accuracy and cost of four methods for assessing stiffness were evaluated: (1) IML hammer, (2) 5-mm outerwood density cores,

R. LEITH KNOWLES; LARS W. HANSEN; ADELE WEDDING; GEOFFREY DOWNES

104

Non-destructive evaluation of plasma sprayed functionally graded thermal barrier coatings  

Microsoft Academic Search

Acoustic emission (AE) as a non-destructive evaluation technique has recently been used in a number of studies to investigate the performance and failure behavior of plasma sprayed thermal barrier coatings. The mechanism of coating failure is complex, especially when considering the composite nature of the coating. In the present paper, the thermal shock tests with in situ acoustic emission are

L Fu; K. A Khor; H. W Ng; T. N Teo

2000-01-01

105

Development of a magnetic corrosion probe for nondestructive evaluation of concrete against corrosion of reinforcing bar  

Microsoft Academic Search

A new magnetic corrosion probe has been developed for nondestructive evaluation of concrete against corrosion of reinforcing bar. Two types of probes, a thin iron wire (probe A) and an iron-plated copper bar (probe B) were tested whether their changes in residual magnetization with progress of corrosion of iron could be detected using a superconducting interference device (SQUID) magnetometer. The

Hitoshi Yashiro; Yusuke Kawamata; Teruaki Kageyama; Shigeyuki Ishikawa; Yuya Tsujimura; Tetsuya Oyamada; Tadashi Fujiwara

2008-01-01

106

Nondestructive evaluation of the oxidation stresses through thermal barrier coatings using Cr3  

E-print Network

The stresses in the aluminum oxide formed during high-temperature oxidation of a bond-coated superalloyNondestructive evaluation of the oxidation stresses through thermal barrier coatings using Cr3 into the growing aluminum oxide scale. Measurements through the thermal barrier coating are feasible because

Clarke, David R.

107

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

E-print Network

in an automotive assembly plant. Each of the two robots visible in the photograph is equipped with a pairA Consortium of the United States Council for Automotive Research Nondestructive Evaluation Automotive Industry September 6, 2006 United States Automotive Materials Partnership, A Consortium

Knowles, David William

108

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

109

Quantitative phase evaluation of dynamic  

E-print Network

conventional phase-contrast microscopy. © 2008 Society of Photo-Optical Instrumentation Engineers. DOI: 10.1117/1.2997375 Keywords: laser scissors; short-coherence interference microscopy; quantitative phase imaging; optical in the 1960s as a source of powerful and highly focused light, researchers have been using lasers in the life

Chen, Zhongping

110

Nondestructive evaluation of a graphite/aluminum composite space radiator panel. Technical report  

SciTech Connect

Graphite aluminum composites which employ graphite fibers for mechanical reinforcement have applications in the aerospace industry. They are particularly attractive for spacecraft thermal management systems due to their ability to efficiently transport heat. The detection and evaluation of damage in structures fabricated from this material is necessary to the efficiency and application of these materials. This technical report presents research on a graphite fiber reinforced aluminum composite space radiator panel. The panel was evaluated after each of four fabrication stages by four nondestructive techniques: ultrasound, x-ray, dye penetrant, and visual inspection. The results illustrate the importance of nondestructive evaluation (NDE) from the time the composite is fabricated through the time it is implemented into the spacecraft. These NDE technologies will help detect external or internal irregularities (anomalies) at each increment of the fabrication and qualification testing of the composite radiator panel.

Feldman, N.M.; Foltz, J.V.

1991-12-01

111

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

112

A report on nondestructive testing and evaluation in India  

SciTech Connect

India is pursuing research and development in various aspects of NDT including in service inspection in fields such as ultrasonic testing, acoustic emission testing, single and multi-frequency eddy current testing, signal analysis, X-ray diffraction, high resolution X-radiography, radiographic image enhancement, laser holography, laser speckle scattering, laser based ultrasonic generation, electromagnetic acoustic transducers, artificial intelligence approaches, and intelligent processing of materials. The emphasis is not only on the methodologies of acquisition of the data but also on the means to analyze them properly so that complete characterization of the type, nature, and size of the defects can be made, as well as their effects on the structural integrity of the components. The approach is comprehensive, the means being total awareness, and the objective is a complete quantitative characterization of defects and other required physical parameters, leading to defect free and safe components and systems.

Raj, B. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Metallurgy and Materials Group; Viswanathan, K. [SHAR, Andhra Pradesh (India); Nair, C.G.K. [Hindustan Aeronautics Limited, Bangalore (India)

1996-11-01

113

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

114

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

115

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

116

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

117

Holographic nondestructive evaluation of spherical kevlar\\/epoxy pressure vessels  

Microsoft Academic Search

Three spherical kevlar\\/epoxy pressure vessels were evaluated using holographic interferograms provide information on the failure modes, displacement profile, and possible fiber damage. The holograms show a symmetric anisotropic displacement pattern even though the vessels failed due to a leak in the aluminum mandrels. The presence of a biconvex fringe pattern found during the testing of vessel three is believed to

D. M. Boyd; B. W. Maxfield

1979-01-01

118

Sensor Placement for Aerospace NonDestructive Evaluation (NDE)  

E-print Network

maintenance and data processing, so we would like to use as few sensors as possible. The ideal formulation­destructive evaluation, aerospace struc­ tures, aging aircraft, futuristic aircraft, neural networks, symmetry groups and more important as the aircraft fleet ages. At present, most airplanes do not have built­in sensors

Ward, Karen

119

Non-destructive evaluation of materials at high temperatures using electro-optic holography  

Microsoft Academic Search

An electro-optic holographic technique for the non-destructive evaluation of materials at high temperatures is presented. The test object is heated in an oven that can attain a temperature of 1000 °C. Electro-optic holography is used for the real-time visualization of full field in-plane displacement fringes. Digital image processing techniques are used for the analysis of fringes. Some of the problems

G. K. Bhat

1996-01-01

120

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

121

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

NASA Technical Reports Server (NTRS)

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

Madras, Eric I. (inventor)

1995-01-01

122

Non-Destructive Evaluation of Wire Insulation and Coatings  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

123

Nondestructive evaluation of residual stress in anisotropic materials  

SciTech Connect

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

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

1990-05-01

124

Nondestructive and quantitative characterization of TRU and LLW mixed-waste using active and passive gamma-ray spectrometry and computed tomography  

SciTech Connect

The technology being proposed by LLNL is an Active and Passive Computed Tomography (A P CT) Drum Scanner for contact-handled (CH) wastes. It combines the advantages offered by two well-developed nondestructive assay technologies: gamma-ray spectrometry and computed tomography (CT). Coupled together, these two technologies offer to nondestructively and quantitatively characterize mixed- wastes forms. Gamma-ray spectroscopy uses one or more external radiation detectors to passively and nondestructively measure the energy spectrum emitted from a closed container. From the resulting spectrum one can identify most radioactivities detected, be they transuranic isotopes, mixed-fission products, activation products or environmental radioactivities. Spectral libraries exist at LLNL for all four. Active (A) or transmission CT is a well-developed, nondestructive medical and industrial technique that uses an external-radiation beam to map regions of varying attenuation within a container. Passive (P) or emission CT is a technique mainly developed for medical application, e.g., single-photon emission CT. Nondestructive industrial uses of PCT are under development and just coming into use. This report discuses work on the A P CT Drum Scanner at LLNL.

Camp, D.C.; Martz, H.E.

1991-11-12

125

[Activities of Center for Nondestructive Evaluation, Iowa State University  

NASA Technical Reports Server (NTRS)

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

Gray, Joe

2002-01-01

126

Nondestructive evaluation of the carbon content in steel  

NASA Astrophysics Data System (ADS)

The aim of this work is to propose an experimental method to evaluate the steel carbon content by ultrasound. The sample is immersed in a water tank in order to analyze it under various incidences of sound waves. Longitudinal wave velocities are measured by immersion by using a 5-MHz frequency probe. Transverse wave velocities are measured in a contact mode by using a 4-MHz transverse wave transducer. The attenuation coefficients of ultrasonic longitudinal and transverse waves are deduced from three successive basic echoes through the sample. The effects of some heat treatments on ultrasonic parameters are also studied. The measurement of ultrasonic parameters in steel offers an interesting possibility of tracing the carbon content and, at the same time, provides information on the steel structure and its elasticity.

Badidi Bouda, A.; Belkhelfa, H.; Djerir, W.; Halimi, R.

2014-05-01

127

Quantitative method of medication system interface evaluation.  

PubMed

The objective of this study was to develop a quantitative method of evaluating the user interface for medication system software. A detailed task analysis provided a description of user goals and essential activity. A structural fault analysis was used to develop a detailed description of the system interface. Nurses experienced with use of the system under evaluation provided estimates of failure rates for each point in this simplified fault tree. Means of estimated failure rates provided quantitative data for fault analysis. Authors note that, although failures of steps in the program were frequent, participants reported numerous methods of working around these failures so that overall system failure was rare. However, frequent process failure can affect the time required for processing medications, making a system inefficient. This method of interface analysis, called Software Efficiency Evaluation and Fault Identification Method, provides quantitative information with which prototypes can be compared and problems within an interface identified. PMID:17625402

Pingenot, Alleene Anne; Shanteau, James; Pingenot, James D F

2007-01-01

128

Nondestructive evaluation of surface roughness by speckle correlation techniques  

NASA Astrophysics Data System (ADS)

The most established way to inspect surface roughness of machined surfaces is to measure with profilometers. These techniques are not applicable for on-line inspection. A few decades ago, the correlation between laser speckles of different light wavelengths and surface roughness was discovered. Since then several authors have been working on this topic. In measuring systems which are considered in this paper, the surface which is to be inspected is illuminated by a polychromatic laser beam. The scattered light is converted by an optical system, which ensures that the product of wavelength times focal length is constant. In the Fourier plane of each subsystem a CCD-array is installed. The CCD- data are captured by a frame grabber and stored for evaluation in a computer. One major problem in industrial processes where surface roughness measurements had ben tried was that the inspected metal workpieces may be tilted and, therefore, the direction of spectral reflection changes. In the method discussed in this paper an approximate value of the surface roughness can be obtained by determining the difference between the zero orders of the scattering patterns of the wavelengths. This difference can be approximated by the position of the maximum of the 2D- cross correlation function of related speckle patterns. The main benefit of the method described is the feasibility of measuring roughness during machining or other types of continuous or semi-continuous production processes. This is achieved by a synchronous detection of speckle patterns of the different wavelengths used. In the pilot project the shutter sped of the cameras is 1/10000 seconds, therefore, in this case only frequencies above 1kHz disturb the measuring results.

Peters, Joerg; Schoene, Armin

1998-03-01

129

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

SciTech Connect

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 [Advanced Composite Evaluation Technology Center, Institute of Space Technology and Aeronautics, Japan Aerospace Exploration Agency, 6-13-1 Ohsawa, Mitaka, Tokyo 181-0015 (Japan)

2005-04-09

130

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

131

Nondestructive evaluation of grain size distributions using multifractal analysis of backscattered ultrasonic signals  

NASA Astrophysics Data System (ADS)

Grain size is one of the factors which influence mechanical properties of metals like strength and fracture toughness. Ultrasonic waves propagating in polycrystalline materials are subject to attenuation dominated by grain boundary scattering. The importance of grain size estimation for industrial applications warrants the investigation of alternative methods of nondestructive grain size determination. Analysis of the power-law behavior of ultrasonic attenuation experimental data is used to link the wavelength dependence of the attenuation coefficient directly to the grain size distribution. The outcome is a simple relationship between the power-law which describes the grain size distribution and the power-law dependence of attenuation on wavelength. Justifications for the use of the power-law for the grain size distribution include scaling and self-similarity. Careful attention is given to the limitations in terms of a practical grain size distribution with finite limits. Two types of measurements are presented to verify the theoretical development: grain size distribution and ultrasonic attenuation. Nickel samples were prepared using three different annealing durations. The attenuation exponent is experimentally shown to be an appropriate nondestructive measurement of the grain size distribution exponent. Further scaling properties for different annealing durations are also explored. A nondestructive evaluation procedure is suggested for metal samples with identical grain size distribution exponents, where the shifts of the log-log representations of the attenuation curves can be used to characterize the different grain size distributions.

Bilgutay, N.; Onaral, B.; Nicoletti, D.

1992-12-01

132

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

PubMed

This paper presents the development of a new non-contact acousto-thermal signature (NCATS) nondestructive evaluation technique. The physical basis of the method is the measurement of the efficiency of the material to convert acoustic energy into heat, and a theoretical model has been used to evaluate this. The increase in temperature due to conversion of acoustic energy injected into the material without direct contact was found to depend on the thermal and elastic properties of the material. In addition, it depends on the experimental parameters of the acoustic source power, the distance between sample and acoustic source, and the period of acoustic excitation. Systematic experimental approaches to optimize each of the experimental variables to maximize the observed temperature changes are described. The potential of the NCATS technique to detect microstructural-level changes in materials is demonstrated by evaluating accumulated damage due to plasticity in Ti-6Al-4V and low level thermal damage in polymer matrix composites. The ability of the technique for macroscopic applications in nondestructive evaluation is demonstrated by imaging a crack in an aluminum test sample. PMID:23020415

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

2012-09-01

133

Non-destructive three-dimensional evaluation of a polymer sponge by micro-tomography using synchrotron radiation.  

PubMed

X-ray micro-tomography, a non-destructive technique is used to uncover the complex 3-D micro-architecture of a degradable polymer sponge designed for bone augmentation. The measurements performed at HASYLAB at DESY are based on a synchrotron radiation source resulting in a spatial resolution of about 5.4 microm. In the present communication we report the quantitative analysis of the porosity and of the pore architecture. First, we elucidate that synchrotron radiation at the photon energy of 9 keV has an appropriate cross section for this low-weight material. Modifications in sponge micro-architecture during measurement are not detected. Second, the treatment of the data, an amount of 2.5 Gbyte to generate binary data is described. We compare the 3-D with the 2-D analysis in a quantitative manner. The obtained values for the mean distance to material within the sponge calculated from 2-D and 3-D data of the whole tomogram differ significantly: 12.5 microm for 3-D and 17.6 microm for 2-D analysis. If the pores exhibit a spherical shape as frequently found, the derived mean pore diameter, however, is overestimated only by 6% in the 2-D image analysis with respect to the 3-D evaluation. This approach can be applied to different porous biomaterials and composites even in a hydrated state close to physiological conditions, where any surface preparation artifact is avoided. PMID:12202165

Müller, Bert; Beckmann, Felix; Huser, Marius; Maspero, Fabrice; Székely, Gábor; Ruffieux, Kurt; Thurner, Philipp; Wintermantel, Erich

2002-08-01

134

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

135

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

136

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

137

Micro-nondestructive evaluation of microelectronics using three-dimensional acoustic imaging  

NASA Astrophysics Data System (ADS)

Holographic-like three-dimensional (3D) acoustic imaging is developed for micro-nondestructive evaluation of microelectronics. It is implemented by stacking all the interface slices together to locate and identify hidden defects. Matching pursuit based acoustic time-frequency domain imaging is proposed to overcome the wavelength limit of axial resolution so that ultra-thin slices are generated. Experiments are performed on 3D acoustic data collected from microelectronic packages. Results show that the proposed technique resolves closely spaced features that are unavailable by conventional acoustic imaging, revealing more image details of defects.

Zhang, Guang-Ming; Harvey, David M.; Burton, David R.

2011-02-01

138

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

PubMed

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

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

2010-01-01

139

Nondestructive and noncontact evaluation on FRP composite laminates using a terahertz ray  

NASA Astrophysics Data System (ADS)

Recently, a terahertz ray (T-ray) technique has emerged as one of the most promising new powerful nondestructive evaluation (NDE) techniques, and new application systems are under processing development for the area applications. In this study T-ray technique will be adopted for the characterization of the FRP composite solid laminates as an imaging and useful nondestructive evaluation (NDE) tool. So, in order to detect and evaluate the flaws in FRP solid composite laminates a new time-domain spectroscopy system was utilized. Various experimental measurements in reflection and through-transmission modes were made in order to map out the T-ray images. Especially in this characterization procedure, we estimated the electromagnetic properties such as the refractive index and a couple of techniques were proposed to measure the refractive index. It is found that estimations of properties with the proposed different ways are in good agreement with known data. Furthermore woven CFRP Honey comb sandwich panel with Al wire were observed in reflection mode and limitations will be mentioned in the T-ray processing.

Park, Je-Woong; Im, Kwang-Hee; Hsu, David K.; Chiou, Chien-Ping; Barnard, Dan; Jung, Jong-An; Yang, In-Young

2011-11-01

140

Nondestructive and noncontact evaluation on FRP composite laminates using a terahertz ray  

NASA Astrophysics Data System (ADS)

Recently, a terahertz ray (T-ray) technique has emerged as one of the most promising new powerful nondestructive evaluation (NDE) techniques, and new application systems are under processing development for the area applications. In this study T-ray technique will be adopted for the characterization of the FRP composite solid laminates as an imaging and useful nondestructive evaluation (NDE) tool. So, in order to detect and evaluate the flaws in FRP solid composite laminates a new time-domain spectroscopy system was utilized. Various experimental measurements in reflection and through-transmission modes were made in order to map out the T-ray images. Especially in this characterization procedure, we estimated the electromagnetic properties such as the refractive index and a couple of techniques were proposed to measure the refractive index. It is found that estimations of properties with the proposed different ways are in good agreement with known data. Furthermore woven CFRP Honey comb sandwich panel with Al wire were observed in reflection mode and limitations will be mentioned in the T-ray processing.

Park, Je-Woong; Im, Kwang-Hee; Hsu, David K.; Chiou, Chien-Ping; Barnard, Dan; Jung, Jong-An; Yang, In-Young

2012-04-01

141

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

142

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

143

Assessing Primary Water Stress Corrosion Crack Morphology and Nondestructive Evaluation Reliability  

SciTech Connect

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

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

2005-12-01

144

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

NASA Astrophysics Data System (ADS)

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

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

145

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

NASA Technical Reports Server (NTRS)

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

Generazio, Edward R.

1992-01-01

146

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

147

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

148

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

NASA Astrophysics Data System (ADS)

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

Ip, Alan; Berszakiewicz, Beata; Pianca, Frank

1998-03-01

149

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

150

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

PubMed Central

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

151

Rapid non-destructive quantitative estimation of urania/thoria in mixed thorium uranium di-oxide pellets by high-resolution gamma-ray spectrometry.  

PubMed

A non-destructive technique using high-resolution gamma-ray spectrometry has been standardised for quantitative estimation of uranium/thorium in mixed (ThO2-UO2) fuel pellets of varying composition. Four gamma energies were selected; two each from the uranium and thorium series and the time of counting has been optimised. This technique can be used for rapid estimation of U/Th percentage in a large number of mixed fuel pellets from a production campaign. PMID:11300408

Shriwastwa, B B; Kumar, A; Raghunath, B; Nair, M R; Abani, M C; Ramachandran, R; Majumdar, S; Ghosh, J K

2001-06-01

152

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

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

153

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

NASA Astrophysics Data System (ADS)

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; Rasselkorde, El Mahjoub; Abbasi, Waheed A.

2014-02-01

154

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

155

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

156

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

157

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 acoustic emission (AE) NDE on the test specimens. The data resulting from this work will be employed for designing multi-sensor data fusion algorithms during the next reporting period.

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

2003-06-01

158

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, thermal imaging and acoustic emission nondestructive evaluation signatures of a test-specimen suite representative of benign and anomalous indications in gas transmission pipelines. Specifically, the algorithms presented in the earlier reports were augmented to predict information related to defect depth (severity).

Shreekanth Mandayam; Robi Polikar; John C. Chen

2005-02-01

159

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

DOEpatents

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

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

1994-05-17

160

Integrated nondestructive evaluation, materials, and fracture mechanics approach to life extension of steam turbine rotors  

NASA Astrophysics Data System (ADS)

The aging hollow forged steel rotors of steam turbine and generator units typical to utility power plants are a major area of concern for the future safety and integrity of the overall power plant. These components are also critical in determining future inspection intervals for the turbine unit and its remaining life. Over the past five years a number of lifetime extension projects have been conducted using an integrated nondestructive evaluation (NDE), materials and fracture mechanics approach to determining inspection intervals and remaining life. These projects have resulted in extending inspection intervals, predicting remaining life, and restoring original equipment manufacturer (OEM) retired rotors to operation. Key aspects of the integrated program will be covered using the results of a recently completed project.

Leon-Salamanca, Teodoro; Reinhart, Eugene R.

1998-03-01

161

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

NASA Technical Reports Server (NTRS)

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

Tiede, D. A.

1972-01-01

162

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

163

Giant Magnetoresistive (GMR) Sensor Microelectromechanical System (MEMS) Device for Nondestructive Evaluation (NDE) Health Monitoring Applications for International Space Station (ISS)  

Microsoft Academic Search

With the imminent launch of the first International Space Station modules, NASA Oflice of Safety and Mission Assurance, specifically the Code Q Nondestructive Evaluation Program, is addressing issues of on-orbit station structural health monitoring. As part of this effort, Jet Propulsion Laboratory is working with NASA's Langley Research Center on development of novel devices and sensors for an NDE tool

R. Ramesham; J. D. Olivas; S. Stokes; W. Wilson; Edward Generazio

164

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

SciTech Connect

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

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

2002-09-19

165

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

166

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

NASA Technical Reports Server (NTRS)

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

Ferguson, Milton W.

1994-01-01

167

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

168

Nondestructive Evaluation of Thermal Spray Coating INterface Quality by Eddy Current Method.  

National Technical Information Service (NTIS)

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 characteri...

B. Mi G. Zhao, R. Bayles

2006-01-01

169

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

170

Laser Doppler technique for nondestructive evaluation of mechanical heart valves kinematics  

NASA Astrophysics Data System (ADS)

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

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

2004-06-01

171

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

NASA Astrophysics Data System (ADS)

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

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

2006-03-01

172

Photoacoustic Non-Destructive Evaluation and Imaging of Caries in Dental Samples  

NASA Astrophysics Data System (ADS)

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

Li, T.; Dewhurst, R. J.

2010-02-01

173

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

NASA Astrophysics Data System (ADS)

We have developed a compensation system for any given SQUID sensor which allows sensitive eddy current measurements above 100 Hz in the presence of strong and slowly varying background fields. High Tc SQUIDs have been used successfully in nondestructive evaluation (NDE) systems based on eddy current excitation when searching for defects in conductive samples such as aircraft parts. Due to their high and frequency independent field resolution and their excellent spatial resolution, SQUIDs provide in the case of deep lying defects—compared to other conventional electromagnetic NDE systems—a more reliable crack detection. Fast readout electronics having an unsurpassed dynamic range of up to eight orders of magnitude enabled us to perform measurements in an environment polluted with electromagnetic noise, e.g., an aircraft hangar. Nevertheless, test objects containing ferromagnetic structures with a high remanent magnetization, such as aircraft wheels or steel bolts in an aircraft wing, very often cause instabilities of the flux-locked loop operation of the SQUID. To prevent unlocking, we have developed a new background field compensation scheme. Special compensation electronics take care of slowly varying magnetic fields of up to 1 mT/s and allow us to perform eddy current measurements in the presence of slow (<30 Hz) background field variations of up to 5 mT.

Kreutzbruck, M. v.; Theiss, A.; Mück, M.; Heiden, C.

1999-09-01

174

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

SciTech Connect

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

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

2002-06-03

175

A new unique electrostatic imager for nondestructive evaluation of printed circuit boards  

NASA Astrophysics Data System (ADS)

A new method (patent pending) was developed at Varian Medical Systems and OHT Inc. for non-destructive evaluation of printed circuit boards (PCB"s). The electrostatic imager uses a TFT array, where each pixel has a small storage capacitor connected to it and a separate top electrode. An insulator layer covers these top electrodes. When we place a PCB on top of this insulator layer and activate a trace of the PCB by an electrical pulse, that trace induces charges in all of the underlying pixels. By reading out the image of the charges with electronics, similar to ones used for digital x-ray imaging, we can reconstruct the image of the electrical trace. Using the above technique we can test and detect defects in PCB"s such as shorted traces, broken traces, etc. This method is also applicable to test other electrical and electronic circuits and components with electrical pulses. The paper gives a detailed descripton of this new imaging technique illustrated by real applications.

Zentai, George; Partain, Larry D.; Proano, Cesar; Yamaoka, Syuji

2003-07-01

176

Application of electronic imaging for characterization of defects in nondestructive evaluation  

NASA Astrophysics Data System (ADS)

Catastrophic failures of major engineering systems such as the space shuttle or nuclear reactor demands more reliable nondestructive evaluation (NDE) technology to maintain a high level of safety. Reliable defect characterization by NDE depends on its efficiency that eliminates the false confidence level in system performance. Also, the modern damage tolerant design based on fracture mechanics requires the reliability and accuracy of the NDE techniques used to detect and characterize flaws. Inspection codes for industrial components specify the sensitivity levels of an inspection method as well as the rejectable flaw size. For complete defect characterization the electronic imaging technique is widely used. In this work, imaging of defects was carried out on thick weldments of SA - 229 pressure vessel steel. Generation of natural defects like cracks were realized by an innovative and reliable welding technique, and NDE techniques, conventional and advanced ones including acoustic holography were used for the crack characterization. Specimens after the test were machined to reveal the cracks and the actual crack morphology was measured and recorded. Through a computer model, the defect image was reconstructed and visualized at different sections. A comparative analysis on the reconstructed image in a computer, the actual one and the NDE result was carried out.

Mani, C.; Homma, Hiroomi; Kanto, Yasuhiro

1997-03-01

177

Phase-contrast x-ray imaging for nondestructive evaluation of materials  

SciTech Connect

Phase-contrast x-ray imaging has been studied intensively in the past, mainly with applications to low density biological materials. In this work experimental and theoretical aspects of phase-contrast microfocus x-ray imaging of structural materials (metals and polymers) are considered. The diffraction field in an object from a point x-ray source is simulated and the effects of geometrical and material parameters on the x-ray phase-contrast image are obtained. It is shown that higher-order terms should be retained in the asymptotic expansion of the Green function in the image plane to accurately image discontinuities in structural materials. Experimental phase-contrast images of small defects are obtained with a 5 {mu}m microfocal x-ray source and compared with those from computer simulation as a function of geometrical magnification and photon energy. The phase-contrast x-ray imaging provides enhanced image contrast and improved edge definition and is important for further development of nondestructive evaluation of structural materials.

Zoofan, B.; Kim, J.-Y.; Rokhlin, S. I.; Frankel, G. S. [Nondestructive Evaluation Program, Edison Joining Technology Center, Ohio State University, Columbus, Ohio 43221 (United States); Fontana Corrosion Center, Department of Materials Science and Engineering, Ohio State University, Columbus, Ohio 43210 (United States)

2006-07-01

178

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

NASA Technical Reports Server (NTRS)

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

Grygler, Micheal S.

1994-01-01

179

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

180

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

SciTech Connect

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

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

1990-04-09

181

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

182

Determining quantitative immunophenotypes and evaluating their implications  

NASA Astrophysics Data System (ADS)

Quantitative immunophenotypes varied widely among > 100 healthy young males but were maintained at characteristic levels within individuals. The initial results (SPIE Proceedings 4260:226) that examined cell numbers and the quantitative expression of adhesion and lineage-specific molecules, e.g., CD2 and CD14, have now been confirmed and extended to include the quantitative expression of inducible molecules such as HLA-DR and perforin (Pf). Some properties, such as the ratio of T helper (Th) to T cytotoxic/suppressor (Tc/s) cells, are known to be genetically determined. Other properties, e.g., the T:B cell ratio, the amount of CD19 per B cell, etc., behaved similarly and may also be inherited traits. Since some patterns observed in these healthy individuals resembled those found in pathological situations we tested whether the patterns could be associated with the occurrence of disease. The current studies shows that there were associations between quantitative immunophenotypes and the subsequent incidence and severity of disease. For example, individuals with characteristically low levels of HLA-DR or B cells or reduced numbers of Pf+ Tc/s cells had more frequent and/or more severe upper respiratory infections. Quantitative immunophenotypes will be more widely measured if the necessary standards are available and if appropriate procedures are made more accessible.

Redelman, Douglas; Hudig, Dorothy; Berner, Dave; Castell, Linda M.; Roberts, Don; Ensign, Wayne

2002-05-01

183

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

SciTech Connect

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

Becker, G.K.

1997-01-01

184

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

185

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

186

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

187

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

Microsoft Academic Search

Thermal imaging cameras now allows routine monitoring of dangerous yet endangered wildlife in captivity. This study looks at the potential applications of radiometrically calibrated thermal data to wildlife, as well as providing parameters for future materials applications. We present a non-destructive active testing technique suitable for enhancing imagery contrast of thin or delicate biological specimens yielding improved thermal contrast at

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

2009-01-01

188

Residual stresses, defects and non-destructive evaluation of FSW joints  

Microsoft Academic Search

This article describes some of the research activities in progress at the German Aerospace Centre, DLR, on the friction stir welding process. It shows in detail the principal defects that can be found in FSW joints, particularly those defects that are due to incomplete filling, incomplete penetration and root discontinuities.The non-destructive ultrasonic method has been used as a promising technique

T. Ghidini; T. Vugrin; C Dalle Donne

2005-01-01

189

Nondestructive evaluation of cementite content in steel and white cast iron using inductive Barkhausen noise  

Microsoft Academic Search

A nondestructive testing method for the determination of the cementite content in iron-carbon steel and white cast iron is presented. The method is based on micromagnetic measuring parameters derived from inductive Barkhausen noise measurements taken under room temperature and with temperatures above the Curie temperature. The influence of different cementite contents and cementite modifications on the micromagnetic measuring quantities for

I. Altpeter

1996-01-01

190

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

191

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

192

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

193

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

194

Quantitative Evaluation of Grammaticality of Summaries  

Microsoft Academic Search

\\u000a Automated evaluation is crucial in the context of automated text summaries, as is the case with evaluation of any of the language\\u000a technologies. While the quality of a summary is determined by both content and form of a summary, throughout the literature\\u000a there has been extensive study on the automatic and semi-automatic evaluation of content of summaries and most such

Ravikiran Vadlapudi; Rahul Katragadda

2010-01-01

195

Applying quantitative models to evaluate complexity in video game systems  

E-print Network

This thesis proposes a games evaluation model that reports significant statistics about the complexity of a game's various systems. Quantitative complexity measurements allow designers to make accurate decisions about how ...

Tanwanteng, Matthew (Matthew E.)

2009-01-01

196

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

197

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

PubMed Central

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

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

2014-01-01

198

Nondestructive Evaluation of Tissue Engineered Articular Cartilage Using Time-Resolved Fluorescence Spectroscopy and Ultrasound Backscatter Microscopy  

PubMed Central

The goal of this study is to evaluate the ability of a bimodal technique integrating time-resolved fluorescence spectroscopy (TRFS) and ultrasound backscatter microscopy (UBM) for nondestructive detection of changes in the biochemical, structural, and mechanical properties of self-assembled engineered articular cartilage constructs. The cartilage constructs were treated with three chemical agents (collagenase, chondroitinase-ABC, and ribose) to induce changes in biochemical content (collagen and glycosaminoglycan [GAG]) of matured constructs (4 weeks); and to subsequently alter the mechanical properties of the construct. The biochemical changes were evaluated using TRFS. The microstructure and the thickness of the engineered cartilage samples were characterized by UBM. The optical and ultrasound results were validated against those acquired via conventional techniques including collagen and GAG quantification and measurement of construct stiffness. Current results demonstrated that a set of optical parameters (e.g., average fluorescence lifetime and decay constants) showed significant correlation (p<0.05) with biochemical and mechanical data. The high-resolution ultrasound images provided complementary cross-section information of the cartilage samples morphology. Therefore, the technique was capable of nondestructively evaluating the composition of extracellular matrix and the microstructure of engineered tissue, demonstrating great potential as an alternative to traditional destructive assays. PMID:22010819

Responte, Donald; Xie, Hongtao; Liu, Jing; Fatakdawala, Hussain; Hu, Jerry; Athanasiou, Kyriacos A.

2012-01-01

199

Qualitative and Quantitative Evaluation of Liver Diseases  

PubMed Central

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

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

1980-01-01

200

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

NASA Astrophysics Data System (ADS)

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

Smith, David C.

2005-08-01

201

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

202

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

NASA Astrophysics Data System (ADS)

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

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

2009-07-01

203

A methodology for quantitative performance evaluation of detection algorithms  

Microsoft Academic Search

We present a methodology for the quantitative performance evaluation of detection algorithms in computer vision. A common method is to generate a variety of input images by varying the image parameters and evaluate the performance of the algorithm, as algorithm parameters vary. Operating curves that relate the probability of misdetection and false alarm are generated for each parameter setting. Such

Tapas Kanungo; Mysore Y. Jaisimha; John Palmer; Robert M. Haralick

1995-01-01

204

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

205

Evaluation of quantitative variation in gene expression.  

PubMed Central

We investigate the behaviour of the gene-expression rate as a statistical variable using autoradiographic data for 39 transcripts from a heterogeneous set of 80 breast-tissue cultures. Despite standardization, the data distributions of all transcripts showed intervals of normality and intervals of systematic departure from normality which most frequently resulted in a significant skewness and/or kurtosis. Non-normal shapes are attributed to modulation of gene expression. This statistical particularity creates difficulties in the evaluation of differences among specimens. Using classical parametric and non-parametric procedures for normal and non-normal variation, respectively, we demonstrate that large differences in optical density are neither necessary nor sufficient for associating expression rates with biological factors. The transcripts coding for the metalloprotease stromelysin-3 (ST3) and for the receptor to insulin-like growth factors (IGFR) are used as examples and their variation is presented in detail. ST3 expression appeared to be specifically associated with mammary stroma fibroblasts derived from post-radiation fibrosis lesions. IGFR was expressed at higher rates in mammary gland and skin fibroblasts than in mammary epithelial cells and was subject to frequent and strong modulation. PMID:8139921

Spanakis, E; Brouty-Boye, D

1994-01-01

206

Evaluation of non-destructive methods for estimating biomass in marshes of the upper Texas, USA coast  

USGS Publications Warehouse

The estimation of aboveground biomass is important in the management of natural resources. Direct measurements by clipping, drying, and weighing of herbaceous vegetation are time-consuming and costly. Therefore, non-destructive methods for efficiently and accurately estimating biomass are of interest. We compared two non-destructive methods, visual obstruction and light penetration, for estimating aboveground biomass in marshes of the upper Texas, USA coast. Visual obstruction was estimated using the Robel pole method, which primarily measures the density and height of the canopy. Light penetration through the canopy was measured using a Decagon light wand, with readings taken above the vegetation and at the ground surface. Clip plots were also taken to provide direct estimates of total aboveground biomass. Regression relationships between estimated and clipped biomass were significant using both methods. However, the light penetration method was much more strongly correlated with clipped biomass under these conditions (R2 value 0.65 compared to 0.35 for the visual obstruction approach). The primary difference between the two methods in this situation was the ability of the light-penetration method to account for variations in plant litter. These results indicate that light-penetration measurements may be better for estimating biomass in marshes when plant litter is an important component. We advise that, in all cases, investigators should calibrate their methods against clip plots to evaluate applicability to their situation. ?? 2006, The Society of Wetland Scientists.

Whitbeck, M.; Grace, J.B.

2006-01-01

207

Rapid, non-destructive evaluation of ultrathin WSe2 using spectroscopic ellipsometry  

NASA Astrophysics Data System (ADS)

The utilization of tungsten diselenide (WSe2) 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) WSe2 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 WSe2 is thinned to the equivalent of 2 atomic layers.

Eichfeld, Sarah M.; Eichfeld, Chad M.; Lin, Yu-Chuan; Hossain, Lorraine; Robinson, Joshua A.

2014-09-01

208

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

209

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

210

Electromagnetic Nondestructive Evaluation of Wire Insulation and Models of Insulation Material Properties  

NASA Technical Reports Server (NTRS)

Polymers have been widely used as wiring electrical insulation materials in space/air-craft. The dielectric properties of insulation polymers can change over time, however, due to various aging processes such as exposure to heat, humidity and mechanical stress. Therefore, the study of polymers used in electrical insulation of wiring is important to the aerospace industry due to potential loss of life and aircraft in the event of an electrical fire caused by breakdown of wiring insulation. Part of this research is focused on studying the mechanisms of various environmental aging process of the polymers used in electrical wiring insulation and the ways in which their dielectric properties change as the material is subject to the aging processes. The other part of the project is to determine the feasibility of a new capacitive nondestructive testing method to indicate degradation in the wiring insulation, by measuring its permittivity.

Bowler, Nicola; Kessler, Michael R.; Li, Li; Hondred, Peter R.; Chen, Tianming

2012-01-01

211

Non-Destructive Evaluation Method of Pharmaceutical Tablet by Terahertz-Time-Domain Spectroscopy: Application to Sound-Alike Medicines  

NASA Astrophysics Data System (ADS)

To evaluate terahertz time-domain spectroscopy (THz-TDS) as a promising tool for discriminating pharmaceutical tablets, THz-TDS has been applied for discrimination between pharmaceutical tablets with sound-alike names. Two sets of medicine tablets with sound-alike names, that is, Amaryl and Almarl, Zyloric and Zantac, are examined in this study. Based on the difference in THz absorption spectra, we have succeeded in distinguishing between sound-alike medicine tablets clearly for each set. The results in this study suggest that THz-TDS is a useful tool that is indispensable for medical security maintenance, such as a non-destructive way to prevent mix-up of medicine.

Kawase, Masaya; Yamamoto, Kohji; Takagi, Keita; Yasuda, Ryohei; Ogawa, Masafumi; Hatsuda, Yasutoshi; Kawanishi, Sonoyo; Hirotani, Yoshihiko; Myotoku, Michiaki; Urashima, Yoko; Nagai, Katsuhito; Ikeda, Kenji; Konishi, Hiroki; Yamakawa, Junji; Tani, Masahiko

2013-09-01

212

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

NASA Astrophysics Data System (ADS)

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.

2014-02-01

213

Simulation of transducer-couplant effects on broadband ultrasonic signals. [in nondestructive flaw evaluation and materials tests  

NASA Technical Reports Server (NTRS)

The increasing use of broadband, pulse-echo ultrasonics in nondestructive evaluation of flaws and material properties has generated a need for improved understanding of the way signals are modified by coupled and bonded thin-layer interfaces associated with transducers. This understanding is most important when using frequency spectrum analyses for characterizing material properties. In this type of application, signals emanating from material specimens can be strongly influenced by couplant and bond-layers in the acoustic path. Computer synthesized waveforms were used to simulate a range of interface conditions encountered in ultrasonic transducer systems operating in the 20to 80-MHz regime. The adverse effects of thin-layer multiple reflections associated with various acoustic impedance conditions are demonstrated. The information presented is relevant to ultrasonic transducer design, specimen preparation, and couplant selection.

Vary, A.

1980-01-01

214

Quantitative, Notional, and Comprehensive Evaluations of Spontaneous Engaged Speech  

ERIC Educational Resources Information Center

This study provides specific evidence regarding the extent to which quantitative measures, common sense notional measures, and comprehensive measures adequately characterize spontaneous, although engaged, speech. As such, the study contributes to the growing body of literature describing the current limits of automatic systems for evaluating…

Molholt, Garry; Cabrera, Maria Jose; Kumar, V. K.; Thompsen, Philip

2011-01-01

215

Quantitative EEG evaluation of multimedia intervention program for ADHD children  

Microsoft Academic Search

This paper deals with a quantitative evaluation for the therapeutic efficacy of a multimedia intervention program applied to ADHD children to improve their cognitive awareness. The multimedia intervention program consisted of 3 levels in which children can carry out several tasks for focusing attention, sustaining attention, and selective attention. The program was made up of 13 sessions over 24 weeks.

Seung Hyun Lee; Jinung An

2011-01-01

216

Quantitatively Evaluation Model for Plants Landscape in Yuhuatai Martyrs Mausoleum  

Microsoft Academic Search

In this paper, the different types of plant landscape in Yuhuatai Martyrs Mausoleum scenic area in Nanjing was studied as an example. 4 of 14 landscape factors affecting the landscape quality were screened, and an evaluation model on the relation between landscape factors and scenic beauty estimation (SBE) was built, which provide a quantitative basis for getting a better understanding

Li Jiang; Guo-Zhong Meng

2010-01-01

217

Quantitative Evaluation of Nuclear Cataract Using Image Analysis  

Microsoft Academic Search

To quantitatively evaluate nuclear lens opacification, we applied image analysis techniques. Utilizing a newly developed anterior eye segment analysis system, Scheimpflug slit images were taken in 65 eyes with transparent lenses and 31 eyes with nuclear cataract. In transparent lenses, scattering light intensity of the anterior fetal nucleus (AFN) was equal to or less than that of the posterior fetal

Kazuyuki Sasaki; Kuruto Fujisawa; Yasuo Sakamoto

1992-01-01

218

A Mixed Quantitative/Qualitative Method Evaluating Compromise Solutions  

E-print Network

have devised for use in such design advice tools. 2 Conflict in collaborative design It is a wiseA Mixed Quantitative/Qualitative Method for Evaluating Compromise Solutions to Conflicts in Collaborative Design Dennis Bahler Dept. of Computer Science North Carolina State University Raleigh, NC 27695

Bahler, Dennis R.

219

Argonne National Laboratory's Nondestructive  

E-print Network

the safe operationof advanced nuclear reactors. Argonne's World-Class Nondestructive Evaluation- of-the-art NDE equipment and glove boxes instrumented for examination of components pulled from and determine sizing. u The under sodium viewing test facility designs and tests ultrasonic/acoustic NDE systems

Kemner, Ken

220

Nondestructive testing and metrology  

Microsoft Academic Search

Attention is given to holographic nondestructive testing where a force is applied to an object located between two holographic exposures. A technique for studying holographic interference fringes by calculating the resolution with a holodiagram is discussed. Holodiagrams, used for the creation and evaluation of holographic images are described with reference to diagram construction, the optimal utilization of the coherence length,

N. Abramson

1978-01-01

221

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

PubMed

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

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

2010-02-01

222

Nondestructive evaluation and real-time monitoring of laser surface hardening.  

SciTech Connect

An infrared process monitor was used to monitor in real-time the infrared emissions during laser surface hardening of ferrous alloys. The signals from the monitor were correlated with the hardness and case depth of the laser-treated tracks. Test data show that a linear relationship exists between the monitor output DC level voltage and hardness up to the maximum hardness possible and also between the monitor output DC level voltage and case depth. This simple relationship makes it easy to monitor process hardness, case depth and quality of laser heat-treated workpiece. A calibration test on a prototypic material can be used to determine the upper and lower bounds of the voltage signals for a sound quality treatment. In-process monitoring or real-time nondestructive measurement of the hardness and depth of the laser transformation hardened case can then be achieved. The monitor is also capable of tracking changes in surface quality or flatness of the part that is being treated.

Xu, Z.; Leong, K.; Reed, C.; Nuclear Engineering Division

2008-09-12

223

A quantitative method for evaluating alternatives. [aid to decision making  

NASA Technical Reports Server (NTRS)

When faced with choosing between alternatives, people tend to use a number of criteria (often subjective, rather than objective) to decide which is the best alternative for them given their unique situation. The subjectivity inherent in the decision-making process can be reduced by the definition and use of a quantitative method for evaluating alternatives. This type of method can help decision makers achieve degree of uniformity and completeness in the evaluation process, as well as an increased sensitivity to the factors involved. Additional side-effects are better documentation and visibility of the rationale behind the resulting decisions. General guidelines for defining a quantitative method are presented and a particular method (called 'hierarchical weighted average') is defined and applied to the evaluation of design alternatives for a hypothetical computer system capability.

Forthofer, M. J.

1981-01-01

224

Destructive and non-destructive density determination: method comparison and evaluation from the Laguna Potrok Aike sedimentary record  

NASA Astrophysics Data System (ADS)

Density measurements play a central role in the characterization of sediment profiles. When working with long records (>100 m), such as those routinely obtained within the frame of the International Continental Scientific Drilling Program, several methods can be used, all of them varying in resolution, time-cost efficiency and source of errors within the measurements. This paper compares two relatively new non-destructive densitometric methods, CT-Scanning and the coherent/incoherent ratio from an Itrax XRF core Scanner, to data acquired from a Multi-sensor core logger Gamma Ray Attenuation Porosity Evaluator (MSCL Grape) and discrete measurements of dry bulk density, wet bulk density and water content. Quality assessment of density measurements is performed at low and high resolution along the Laguna Potrok Aike (LPA) composite sequence. Giving its resolution (0.4 mm in our study), its high signal to noise ratio, we conclude that CT-Scan provides a precise, fast and cost-efficient way to determine density variation of long sedimentary record. Although more noisy that the CT-Scan measurements, coherent/incoherent ratio from the XRF core scanner also provides a high-resolution, reliable continuous measure of density variability of the sediment profile. The MSCL Grape density measurements provide actual density data and have the significant advantage to be completely non-destructive since the acquisition is performed on full cores prior to opening. However, the quality MSCL Grape density measurements can potentially be reduced by the presence of voids within the sediment core tubes and the dry and bulk density measurements suffers from sampling challenges and are time-consuming.

PASADO Science Team Fortin, David; Francus, Pierre; Gebhardt, Andrea Catalina; Hahn, Annette; Kliem, Pierre; Lisé-Pronovost, Agathe; Roychowdhury, Rajarshi; Labrie, Jacques; St-Onge, Guillaume

2013-07-01

225

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

226

Waterless coupling of ultrasound from planar contact transducers to curved and irregular surfaces during non-destructive ultrasonic evaluations  

NASA Astrophysics Data System (ADS)

The Applied Physics group at the Pacific Northwest National Laboratory (PNNL) in Richland, WA has evaluated a method for waterless/liquidless coupling of ultrasonic energy from planar ultrasonic contact transducers to irregular test surfaces for ultrasonic non-destructive evaluation applications. Dry couplant material placed between a planar transducer face and a curved or uneven steel or plastic surface allows for effective sound energy coupling and preserves the integrity of the planar transducer sound field by serving as an acoustic impedance matching layer, providing good surface area contact between geometrically dissimilar surfaces and conforming to rough and unsmooth surfaces. Sound fields radiating from planar ultrasonic contact transducers coupled to curved and uneven surfaces using the dry coupling method were scanned and mapped using a Pinducer receiver connected to a raster scanner. Transducer sound field coverage at several ultrasonic frequencies and several distances from the transducer contact locations were found to be in good agreement with theoretical beam divergence and sound field coverage predictions for planar transducers coupled to simple, planar surfaces. This method is valuable for applications that do not allow for the use of traditional liquid-based ultrasonic couplants due to the sensitivity of the test materials to liquids and for applications that might otherwise require curved transducers or custom coupling wedges. The selection of dry coupling material is reported along with the results of theoretical sound field predictions, the laboratory testing apparatus and the empirical sound field data.

Denslow, Kayte; Diaz, Aaron; Jones, Mark; Meyer, Ryan; Cinson, Anthony; Wells, Mondell

2012-04-01

227

Nondestructive Evaluation (NDE) of Crack Formation in Advanced Composite Materials and Aluminum During Dynamic Fatigue Tests by SQUID Magnetometry.  

National Technical Information Service (NTIS)

This report results from a contract tasking Universite Pierre et Marie Curie (Paris 6) as follows: The contractor will investigate the use or high sensitivity, nondestructive, SQUID magnetometry to detect and understand crack formation and propagation in ...

H. R. Kokabi

2003-01-01

228

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 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.

2001-01-01

229

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

230

Non-Destructive Evaluation Techniques, High Temperature Ceramic Component Parts for Gas Turbines.  

National Technical Information Service (NTIS)

This report concerns studies conducted on various tests undertaken on material without destroying the material. Tests included: microradiographic techniques, vibration analysis, high-frequency ultrasonic tests with the addition of evaluation of defects an...

H. Reiter, S. Hirsekorn, J. Lottermoser, K. Goebbels

1984-01-01

231

Nondestructive evaluation of an environmentally friendly conversion coating for magnesium alloys using optical measurement techniques  

E-print Network

these harmful chromates out of the coating system and continue to use magnesium alloys, an environmentally friendly conversion coating has been developed. This paper explores the best types of methods used to evaluate the thickness and coating coverage...

Zuniga, David

2006-10-30

232

Method Developed for the High-Temperature Nondestructive Evaluation of Fiber-Reinforced Silicon Carbide Ceramic Matrix Composites  

NASA Technical Reports Server (NTRS)

Ceramic matrix composites have emerged as candidate materials to allow higher operating temperatures (1000 to 1400 C) in gas turbine engines. A need, therefore, exists to develop nondestructive methods to evaluate material integrity at the material operating temperature by monitoring thermal and mechanical fatigue. These methods would also have potential as quality inspection tools. The goal of this investigation at the NASA Lewis Research Center is to survey and correlate the temperature-dependent damping and stiffness of advanced ceramic composite materials with imposed thermal and stress histories that simulate in-service turbine engine conditions. A typical sample size of 100 by 4 by 2 cubic millimeters, along with the specified stiffness and density, placed the fundamental vibration frequencies between 100 and 2000 Hz. A modified Forster apparatus seemed most applicable to simultaneously measure both damping and stiffness. Testing in vacuum reduced the effects of air on the measurements. In this method, a single composite sample is vibrated at its fundamental tone; then suddenly, the mechanical excitation is removed so that the sample's motion freely decays with time. Typical results are illlustrated in this paper.

Goldsby, Jon C.

1998-01-01

233

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

234

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

235

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

236

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

237

Development of nondestructive evaluation techniques for high-temperature ceramic heat exchanger components. Ninth quarterly report, October-December 1979  

SciTech Connect

Progress in developing and evaluating nondestructive methods for testing ceramic components for high-temperature heat exchangers is reported. The sensitivity of the ultrasonic bore-side probe was demonstrated for detection of 125-..mu..m-deep circumferential EDM notches on ID and OD surfaces of sintered and siliconized tubes. The signal to noise ratios for the ultrasonic echoes are better than 10 to 1, beyond the initial expectations for detection of small reflectors. This results from focussing of the beam in the tube wall. Preliminary data were presented on microprocessor-controlled operation of the ultrasonic probe. Some problems involving the computer interfacing have to be resolved, but detection and recording of an EDM notch located was demonstrated. The acoustic microscope was modified to handle 30-MHz sound waves. This was done to improve the penetration ability of the sound in SiC tube walls. The modification results in less acoustic noise. The ability to detect a notch only 75 ..mu..m in width was demonstrated.

Not Available

1980-01-01

238

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

NASA Astrophysics Data System (ADS)

At room temperature and atmospheric conditions infrared reflectance spectroscopy and X-ray diffraction were employed for the detection of the phase transformation and residual stress within thermal barrier coatings (TBC). The TBC's samples initially consisted of the porous ceramic topcoat deposited by electron beam plasma vapor deposition, a bond coat and a superalloy substrate. Reflectance spectroscopy scans were performed from 7497 cm-1 to 68 cm-1 to analysis the fingerprint region as well as the chemical bonding region. These regions should indicate if a detectable change within the TBC response is a result of thermal degradation of the microstructure and the changes in yttrium dispersion throughout the yttrium stabilized zirconium. The thermal degradation was induced by thermal cycling the samples to 1100° C and then cooling them in an atmospheric environment. X-ray diffraction was also used to detect the phase composition within the TBC samples and see if either would clearly identify failure prior to actual spallation. The eventual measurability and quantify-ability of the phase changes within the TBC's may be used as an effective non-destructive evaluation (NDE) technique that would allow personnel in the field to know when servicing of the turbine blade was necessary.

Flattum, Richard Y.; Cooney, Adam T.

2013-01-01

239

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

240

Nondestructive Inspection and Life Determination of Disc Material.  

National Technical Information Service (NTIS)

The prime role of nondestructive evaluation is to support development and validation of the two main processes: the materials and manufacturing method design and engineering design of the engine. The second role of nondestructive evaluation is to monitor,...

H. K. Craig

1991-01-01

241

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

E-print Network

and the results are verified by experiments. © 1996 Acoustical Society of America. PACS numbers: 43.35.Zc, 43 evaluation of solid plates. A common method to excite Lamb waves in composite plates is by mode conversion- metric or probe beam deflection schemes it is possible to detect small displacements.9,10 Generation

Khuri-Yakub, Butrus T. "Pierre"

242

Non-destructive evaluation techniques, high temperature ceramic component parts for gas turbines  

NASA Technical Reports Server (NTRS)

This report concerns studies conducted on various tests undertaken on material without destroying the material. Tests included: microradiographic techniques, vibration analysis, high-frequency ultrasonic tests with the addition of evaluation of defects and structure through analysis of ultrasonic scattering data, microwave tests and analysis of sound emission.

Reiter, H.; Hirsekorn, S.; Lottermoser, J.; Goebbels, K.

1984-01-01

243

Intelligent system for non-destructive evaluation of historic walls using Ground-Penetrating Radar  

Microsoft Academic Search

This paper presents a novel system evaluation of ashlar masonry walls inspec Penetrating Radar (GPR). The system inclu processing of the GPR signal: elimination o from the backscattered signals; depth reso automatic gain control for visualization generation of B-Scans (radargrams) of the in wall. Inhomogeneities in the structure of the from the B-Scans. Several experiments we models of historic ashlar

Gonzalo Safont; Addisson Salazar; Jorge Gosalbez; Luis Vergara

2010-01-01

244

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

245

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

246

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

247

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

248

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

249

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

250

Nondestructive evaluation of neutron irradiation embrittlement for reactor vessel steel by magnetomechanical acoustic emission technique  

SciTech Connect

A modified magnetomechanical acoustic emission (MAE) technique denoted Pulse MAE, in which the magnetizing current has a rectangular wave form, was developed as an NDE technique. Its applicability to the radiation damage for reactor pressure vessel steel was evaluated. The reactor pressure vessel steel A533B base metal and weld metal were irradiated to the two fluence levels: 5 {times} 10{sup 22} and 3 {times} 10{sup 23} n/m{sup 2} at 288 C. One side of the specimen was electropolished after irradiation. Pulse MAE signals were measured with a 350 kHz resonance frequency AE sensor at the moment when the magnetizing voltage is applied from zero to the set-up value abruptly. The AE signals were analyzed and the peak voltage Vp was determined for the measuring parameter. The peak voltage Vp showed the tendency to increase monotonically with increasing neutron fluence. The relationship between the Vp and mechanical properties such as yield stress, tensile strength and Charpy transition temperature were also obtained. The Pulse MAE technique proved to have the possibility to detect and evaluate the neutron irradiation embrittlement. The potential of the Pulse MAE as an effective NDE technique and applicability to the actual components are discussed.

Maeda, Noriyoshi; Yamaguchi, Atsunori [Japan Power Engineering and Inspection Corp., Yokohama (Japan); Saito, Kiyoshi; Hirasawa, Taiji; Komura, Ichiroh; Chujou, Noriyuki [Toshiba Corp., Yokohama (Japan)

1999-10-01

251

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

252

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

NASA Astrophysics Data System (ADS)

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; Drinkwater, Bruce W.

2014-02-01

253

Symposium on Nondestructive Evaluation, 14th, San Antonio, TX, April 19-21, 1983, Proceedings  

SciTech Connect

Topics on scattering of ultrasonic waves by subsurface cracks, the effects of the edges of samples on eddy-current flaw evaluation, ultrasonic reflection from a stressed interface, ultrasonic signal processing for multilayered NDE, and flaw characterization by power spectrum matching are presented. Consideration is given to modeling of ultrasonic flaw detection, development of an acoustic model for multilayered NDE, ultrasonic pulse-echo techniques for curved surfaces, identification of deformation mechanisms by classification of acoustic emission signals, and analysis of pulsed thermal inspection. In addition, a translucency test, a fast-recovery high-voltage pulser for ultrasonic transducers, and an acoustical holographic/pulse echo pressure vessel imaging system, using computer reconstruction and multi-image integration techniques, are described.

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

1985-01-01

254

Voluntary Consensus Organization Standards for Nondestructive Evaluation of Thin-Walled Metallic Liners and Composite Overwraps in Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

NASA fracture control requirements outlined in NASA-STD-5009 and NASA-STD-5014 are predicated on the availability and use of sensitive nondestructive evaluation (NDE) methods that can detect and monitor defects, thereby providing data that can be used to predict failure or reduce the risk of failure in fracture critical components. However, in the case of composite materials and components, including composite overwrapped pressure vessels (COPVs), the effect of defects is poorly understood, the NDE methods used to evaluate locate and size defects are typically at lower technical readiness level than analogous NDE methods used for metals, and demonstration studies to verify the probability of detection (POD) are generally lacking or unavailable. These factors together make failure prediction of fracture critical composite materials and components based on size, quantity, or orientation of defects nearly impossible. Also, when inspecting metal liners in as-manufactured COPVs, sensitivity is lost and only the inner surface of the liner is accessible. Also, NDE of COPVs as applied during manufacturing varies significantly from manufacturer to manufacturer and has not yet been standardized. Although requirements exist to perform NDE immediately after manufacturing to establish initial integrity of the parts, procedural detail for NDE of composites is still nonexistent or under development. For example, in practice, only a visual inspection of COPVs is performed during manufacturing and service, leaving in question whether defects of concern, for example, bridging, overwrap winding anomalies, impact damage below visible threshold, out-of-family strain growth, and liner buckling have been adequately detected and monitored. To address these shortcomings, in 2005 the NASA Nondestructive Evaluation Working Group (NNWG) began funding work to develop and adopt standards for nondestructive evaluation of aerospace composites in collaboration with the American Society for Testing and Materials (ASTM) Committee E07 on Nondestructive Testing. Similarly, in 2006 the NASA Engineering and Safety Center (NESC) recommended that nondestructive evaluation methods that can predict composite failure in COPVs should be developed and verified, and integrated into the damage control plan for these vessels

Waller, Jess; Saulsberry, Regor

2012-01-01

255

Non-destructive evaluation of laminated composite plates using dielectrometry sensors  

NASA Astrophysics Data System (ADS)

The use of composite materials in marine, aerospace and automotive applications is increasing; however, several kinds of damages of composite materials may influence its durability and future applications. In this paper, a methodology was presented for damage detection of laminated composite plates using dielectrometry sensors. The presence of damage in the laminated composite plate leads to changes in its dielectric characteristics, causing variation in the measured capacitance by the sensors. An analytical model was used to analyse the influence of different sensor parameters on the output signals and to optimize sensor design. Two-dimensional finite element (FE) simulations were performed to assess the validity of the analytical results and to evaluate other sensor design-related parameters. To experimentally verify the model, the dielectric permittivity of the composite plate was measured. In addition, a glass fibre reinforced polymer (GFRP) laminated plate containing pre-fabricated slots through its thickness to simulate delamination and water intrusion defects was inspected in a laboratory setting. Excellent agreements were found between the experimental capacitance response signals and those predicated from the FE simulations. This cost-effective technique can be used for rapid damage screening, regular scheduled inspection, or as a permanent sensor network within the composite system.

Nassr, Amr A.; El-Dakhakhni, Wael W.

2009-05-01

256

Nondestructive evaluation methods to measure inside diameters of steam generator tubing: Topical report  

SciTech Connect

Numerous steam generators have experienced tube deformation or denting at support plate intersections due to localized mechanical forces exerted by a magnetite corrosion product within tube and carbon steel support plate annulus. In extreme cases, this denting has led to the early replacement of some steam generators, i.e., Surry and Turkey Point. In addition to monitoring the steam generator for tube wall degradation it has become apparent that it is also desirable to monitor the condition of dented tube-support plate intersections during scheduled inservice inspections. To this end, the acquisition of accurate and reliable information with regards to dent shape is important in establishing tube strain and identifying dent growth rates. This report summarizes the results of a round-robin evaluation conducted in 1983 using then available state-of-the-art technology for assessing dented tubes. More specifically, the capability of various systems for profiling and providing estimates of tube inner diameter on known dent shapes was demonstrated.

Brown, S.; Krzywosz, K.; Cox, J.; Elmo, P.M.

1988-07-01

257

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

SciTech Connect

Characterization of ceramic matrix composites (continuous and whisker-type) by nondestructive evaluation (NDE) methods and an understanding of fracture behavior, together with correlation of fracture and NDE data, may provide insight into the prediction of component performance and the development of process technology. Knowledge of the degradation extent of fiber tows or monofilament degradation after processing, extent of open porosity before densification, and filament/fiber alignments before and after processing are also examples of important variables to be measured. Work in this program has emphasized continuous fiber ceramic matrix composites (CFCCs) that use chemical vapor infiltration (CVI)-infiltrated SiC/SiC materials, primarily those made of Nicalon satin or plain weave with 16 {times} 16 tows/in. in 2-D layups. All studied samples were provided by Oak Ridge National Laboratory and were made using 100 layers per inch. CVI specimens with 0/30/60, 0/90, and 0/45 were examined by 3-D X-ray microtomography to characterize in-plane fiber orientations. Current information suggests that for Nicalon-type fiber architecture, a {plus_minus}2--1/2{degrees} misalignment may not affect mechanical properties. Thus the near-term goal has been to establish a detection capability for angular orientation. By using 512 {times} 512 images from 3-D X-ray CT data with pixel sizes of < 140 {mu}m and a special 2-D fast-Fourier transform image processing analysis, we have shown that fiber orientations to {plus_minus}2--1/2{degrees} with SiC/SiC CVI type 2-D weave architecture can be measured.

Ellingson, W.A.; Singh, J.P.; Holloway, D.L.; Dieckman, S.L.; Singh, D.; Sivers, E.A.; Sheen, S.H.; Wheeler, M.J.

1992-05-01

258

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

SciTech Connect

Characterization of ceramic matrix composites (continuous and whisker-type) by nondestructive evaluation (NDE) methods and an understanding of fracture behavior, together with correlation of fracture and NDE data, may provide insight into the prediction of component performance and the development of process technology. Knowledge of the degradation extent of fiber tows or monofilament degradation after processing, extent of open porosity before densification, and filament/fiber alignments before and after processing are also examples of important variables to be measured. Work in this program has emphasized continuous fiber ceramic matrix composites (CFCCs) that use chemical vapor infiltration (CVI)-infiltrated SiC/SiC materials, primarily those made of Nicalon satin or plain weave with 16 {times} 16 tows/in. in 2-D layups. All studied samples were provided by Oak Ridge National Laboratory and were made using 100 layers per inch. CVI specimens with 0/30/60, 0/90, and 0/45 were examined by 3-D X-ray microtomography to characterize in-plane fiber orientations. Current information suggests that for Nicalon-type fiber architecture, a {plus minus}2--1/2{degrees} misalignment may not affect mechanical properties. Thus the near-term goal has been to establish a detection capability for angular orientation. By using 512 {times} 512 images from 3-D X-ray CT data with pixel sizes of < 140 {mu}m and a special 2-D fast-Fourier transform image processing analysis, we have shown that fiber orientations to {plus minus}2--1/2{degrees} with SiC/SiC CVI type 2-D weave architecture can be measured.

Ellingson, W.A.; Singh, J.P.; Holloway, D.L.; Dieckman, S.L.; Singh, D.; Sivers, E.A.; Sheen, S.H.; Wheeler, M.J.

1992-05-01

259

Development of Transmission Raman Spectroscopy towards the in line, high throughput and non-destructive quantitative analysis of pharmaceutical solid oral dose.  

PubMed

Transmission Raman spectroscopy (TRS) is a recently introduced analytical technique to pharmaceutical analysis permitting volumetric sampling by non-destructive means. Here we demonstrate experimentally, for the first time, the enhanced speed of quantification of pharmaceutical tablets by an order of magnitude compared with conventional TRS. This is achieved using an enhancing element, "photon diode", avoiding the loss of laser photons at laser coupling interface. The proof-of-concept experiments were performed on a complex mixture consisting of 5 components (3 APIs and 2 excipients) with nominal concentrations ranging between 0.4 and 89%. Acquisition times as short as 0.01 s were reached with satisfactory quantification accuracy for all the sample components. Results suggest that even faster sampling speeds would be achievable for components with stronger Raman scattering cross sections or with higher laser powers. This major improvement in speed of volumetric analysis enables high throughput deployment of TRS for in line quality control applications within the batch or continuous manufacturing process and facilitating non-destructive analysis of large fractions. PMID:25360447

Griffen, Julia A; Owen, Andrew W; Matousek, Pavel

2014-12-01

260

QUANTITATIVE ANALYSIS OF SURFACE BARKHAUSEN NOISE MEASUREMENTS  

E-print Network

College of Canada, Kingston, ON, K7K 7B4 ABSTRACT. Barkhausen noise is tiie result of abrupt magnetic response to elastic stress [3]. Consistent BN requires that M be reproduced for each measurement. A general in the student poster competition of 2007 CP975, Review of Quantitative Nondestructive Evaluation Vol. 27, ed

Clapham, Lynann

261

Quantitative genetic activity graphical profiles for use in chemical evaluation  

SciTech Connect

A graphic approach, terms a Genetic Activity Profile (GAP), was developed to display a matrix of data on the genetic and related effects of selected chemical agents. The profiles provide a visual overview of the quantitative (doses) and qualitative (test results) data for each chemical. Either the lowest effective dose or highest ineffective dose is recorded for each agent and bioassay. Up to 200 different test systems are represented across the GAP. Bioassay systems are organized according to the phylogeny of the test organisms and the end points of genetic activity. The methodology for producing and evaluating genetic activity profile was developed in collaboration with the International Agency for Research on Cancer (IARC). Data on individual chemicals were compiles by IARC and by the US Environmental Protection Agency (EPA). Data are available on 343 compounds selected from volumes 1-53 of the IARC Monographs and on 115 compounds identified as Superfund Priority Substances. Software to display the GAPs on an IBM-compatible personal computer is available from the authors. Structurally similar compounds frequently display qualitatively and quantitatively similar profiles of genetic activity. Through examination of the patterns of GAPs of pairs and groups of chemicals, it is possible to make more informed decisions regarding the selection of test batteries to be used in evaluation of chemical analogs. GAPs provided useful data for development of weight-of-evidence hazard ranking schemes. Also, some knowledge of the potential genetic activity of complex environmental mixtures may be gained from an assessment of the genetic activity profiles of component chemicals. The fundamental techniques and computer programs devised for the GAP database may be used to develop similar databases in other disciplines. 36 refs., 2 figs.

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

1990-12-31

262

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

263

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

264

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

265

Quantitative evaluation of carotid arterial plaque surface irregularity  

NASA Astrophysics Data System (ADS)

Recent studies have demonstrated that atherosclerotic plaque surface morphology in the carotid arterial system represents an independent risk factor for embolus formation and subsequent cerebrovascular occlusive events. The primary aim of the current retrospective study is to enhance the clinical utility of this key finding by developing and evaluating objective, quantitative methods for characterizing plaque surface irregularity from Gadolinium-enhanced magnetic resonance angiography (MRA) studies. Nine metrics were analyzed for correlation with percent stenosis in 78 arteries from 43 patients with carotid artery disease. Most of the metrics comprised measurements obtained from a surface model of the stenotic lesion derived from the MRA via the Marching Cubes algorithm with application of the Isosurface Deformable Model. Percent stenosis was determined through real-time volume rendering of 3D MIP MRA studies in Vitrea2. Six of the analyzed metrics revealed significant correlation to percent stenosis (p<0.01). Reproducibility of all metrics was evaluated in a set of 14 randomly selected arteries from 13 patients by way of a single-trial, two-observer analysis. Six of the nine metrics demonstrated significant inter-observer reproducibility by way of single-factor ANOVA analysis (p<0.02). Collectively, the findings reported herein demonstrate an objective and reliable method for quantifying carotid plaque surface irregularity from standard MRA techniques with possible future clinical application in refining risk of ischemic cerebrovascular events and associated need for prophylactic intervention.

Robinson, Joshua; Brevetti, Lucy S.; Yim, Peter J.

2006-03-01

266

Nondestructive testing by speckle-shearing interferometry  

Microsoft Academic Search

The paper presents a new optical method of nondestructive evaluation which utilizes a speckle-shearing interferometric technique. This new method is referred to as SNDT. SNDT is generally superior to holographic nondestructive testing (HNDT) in the sense that it measures displacement derivatives instead of displacement. Since strains are functions of displacement derivatives, it is easier to correlate imperfections with strain anomalies

Y. Y. Hung; J. D. Hovanesian

1979-01-01

267

Multiscale monitoring of interface failure of brittle coating/ductile substrate systems: A non-destructive evaluation method combined digital image correlation with acoustic emission  

NASA Astrophysics Data System (ADS)

In this paper, we proposed a non-destructive evaluation method combined digital image correlation with acoustic emission techniques. The method was used to in situ monitor interface failure and internal damage of brittle coating/ductile substrate systems with different size scales. The results show that there is a good relationship between digital image correlation and acoustic emission signals, which can be applied to judge cracking formation and coating delamination and to determine fracture toughness of a thermal barrier coating system subjected to bending.

Mao, W. G.; Wu, D. J.; Yao, W. B.; Zhou, M.; Lu, C.

2011-10-01

268

Evaluation of the Virus Counter® for rapid baculovirus quantitation  

PubMed Central

The utility of a new instrument for rapid virus quantitation, the Virus Counter, was evaluated in a blind study conducted at three sites. This instrument is a substantially improved version of the original academic research instrument described previously by Stoffel et al. (2005a). The addition of hydrodynamic focusing, a self-contained fluidics system and customized software for system control and data analysis has resulted in a commercially viable and available design. Baculovirus samples were provided by Protein Sciences Corporation and blinded to InDevR and Baylor College of Medicine. Protein Sciences Corporation and Baylor College of Medicine analyzed the samples by plaque assay and InDevR analyzed the samples using the Virus Counter. Serial dilution of stock viruses into growth media and buffer allowed for comparison of measured versus intended concentrations. Direct log-scale comparison between pooled Virus Counter results and pooled plaque assay results indicated a linear relationship (slope = 1.1 ± 0.2, R2 = 0.86) with statistically significant Pearson correlation (r = 0.93, p < 0.001). PMID:20970458

Ferris, Matthew M.; Stepp, Patricia C.; Ranno, Kirk A.; Mahmoud, Wafaa; Ibbitson, Elizabeth; Jarvis, James; Cox, Manon M.J.; Christensen, Kurt; Votaw, Heather; Edwards, Dean P.; Rowlen, Kathy L.

2010-01-01

269

Quantitative evaluation of photoplethysmographic artifact reduction for pulse oximetry  

NASA Astrophysics Data System (ADS)

Motion artefact corruption of pulse oximeter output, causing both measurement inaccuracies and false alarm conditions, is a primary restriction in the current clinical practice and future applications of this useful technique. Artefact reduction in photoplethysmography (PPG), and therefore by application in pulse oximetry, is demonstrated using a novel non-linear methodology recently proposed by the authors. The significance of these processed PPG signals for pulse oximetry measurement is discussed, with particular attention to the normalization inherent in the artefact reduction process. Quantitative experimental investigation of the performance of PPG artefact reduction is then utilized to evaluate this technology for application to pulse oximetry. While the successfully demonstrated reduction of severe artefacts may widen the applicability of all PPG technologies and decrease the occurrence of pulse oximeter false alarms, the observed reduction of slight artefacts suggests that many such effects may go unnoticed in clinical practice. The signal processing and output averaging used in most commercial oximeters can incorporate these artefact errors into the output, while masking the true PPG signal corruption. It is therefore suggested that PPG artefact reduction should be incorporated into conventional pulse oximetry measurement, even in the absence of end-user artefact problems.

Hayes, Matthew J.; Smith, Peter R.

1999-01-01

270

Non-contact, non-destructive, quantitative probing of interfacial trap sites for charge carrier transport at semiconductor-insulator boundary  

NASA Astrophysics Data System (ADS)

The density of traps at semiconductor-insulator interfaces was successfully estimated using microwave dielectric loss spectroscopy with model thin-film organic field-effect transistors. The non-contact, non-destructive analysis technique is referred to as field-induced time-resolved microwave conductivity (FI-TRMC) at interfaces. Kinetic traces of FI-TRMC transients clearly distinguished the mobile charge carriers at the interfaces from the immobile charges trapped at defects, allowing both the mobility of charge carriers and the number density of trap sites to be determined at the semiconductor-insulator interfaces. The number density of defects at the interface between evaporated pentacene on a poly(methylmethacrylate) insulating layer was determined to be 1012 cm-2, and the hole mobility was up to 6.5 cm2 V-1 s-1 after filling the defects with trapped carriers. The FI-TRMC at interfaces technique has the potential to provide rapid screening for the assessment of interfacial electronic states in a variety of semiconductor devices.

Choi, Wookjin; Miyakai, Tomoyo; Sakurai, Tsuneaki; Saeki, Akinori; Yokoyama, Masaaki; Seki, Shu

2014-07-01

271

Nondestructive testing by holographic interferometry  

Microsoft Academic Search

Conditions for the application of holographic interferometry as a means of nondestructive evaluation are discussed. Following a brief review of the principles of holographic interferometry, factors influencing the quality of the hologram are examined, with attention given to the parameters of the laser light source, the photographic plates, image reconstruction, the optical elements and the mechanical stability of the apparatus.

A. Piodi

1979-01-01

272

Quantitative comparison between crowd models for evacuation planning and evaluation  

NASA Astrophysics Data System (ADS)

Crowd simulation is rapidly becoming a standard tool for evacuation planning and evaluation. However, the many crowd models in the literature are structurally different, and few have been rigorously calibrated against real-world egress data, especially in emergency situations. In this paper we describe a procedure to quantitatively compare different crowd models or between models and real-world data. We simulated three models: (1) the lattice gas model, (2) the social force model, and (3) the RVO2 model, and obtained the distributions of six observables: (1) evacuation time, (2) zoned evacuation time, (3) passage density, (4) total distance traveled, (5) inconvenience, and (6) flow rate. We then used the DISTATIS procedure to compute the compromise matrix of statistical distances between the three models. Projecting the three models onto the first two principal components of the compromise matrix, we find the lattice gas and RVO2 models are similar in terms of the evacuation time, passage density, and flow rates, whereas the social force and RVO2 models are similar in terms of the total distance traveled. Most importantly, we find that the zoned evacuation times of the three models to be very different from each other. Thus we propose to use this variable, if it can be measured, as the key test between different models, and also between models and the real world. Finally, we compared the model flow rates against the flow rate of an emergency evacuation during the May 2008 Sichuan earthquake, and found the social force model agrees best with this real data.

Viswanathan, Vaisagh; Lee, Chong Eu; Lees, Michael Harold; Cheong, Siew Ann; Sloot, Peter M. A.

2014-02-01

273

A first evaluation of the usefulness of feathers of nestling predatory birds for non-destructive biomonitoring of persistent organic pollutants.  

PubMed

In previous studies, feathers of adult predatory birds have been evaluated as valid non-destructive biomonitor matrices for persistent organic pollutants (POPs). In this study, we assessed for the first time the usefulness of nestling raptor feathers for non-destructive biomonitoring of POPs. For this purpose, we collected body feathers and blood of nestlings from three avian top predators from northern Norway: northern goshawks (Accipiter gentilis), white-tailed eagles (Haliaeetus albicilla) and golden eagles (Aquila chrysaetos). We were able to detect a broad spectrum of legacy POPs in the nestling feathers of all three species (? PCBs: 6.78-140ng g(-1); DDE: 3.15-145ng g(-1); ? PBDEs: 0.538-7.56ng g(-1)). However, these concentrations were lower compared to other studies on raptor species, probably due to the aspect of monitoring of nestlings instead of adults. Besides their analytical suitability, nestling feathers also appear to be biologically informative: concentrations of most POPs in nestling feathers showed strong and significant correlations with blood plasma concentrations in all species (p<0.050; 0.775non-destructive biomonitoring strategy for POPs in their ecosystems. PMID:21256594

Eulaers, Igor; Covaci, Adrian; Herzke, Dorte; Eens, Marcel; Sonne, Christian; Moum, Truls; Schnug, Lisbeth; Hanssen, Sveinn Are; Johnsen, Trond Vidar; Bustnes, Jan Ove; Jaspers, Veerle L B

2011-04-01

274

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

NASA Technical Reports Server (NTRS)

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

Miller, James G.

1994-01-01

275

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

276

Longitudinal flexural mode utility in quantitative guided wave evaluation  

NASA Astrophysics Data System (ADS)

Longitudinal Non-axisymmetric flexural mode utility in quantitative guided wave evaluation is examined for pipe and tube inspection. Attention is focused on hollow cylinders. Several source loading problems such as a partial-loading angle beam, an axisymmetric comb transducer and an angle beam array are studied. The Normal Mode Expansion method is employed to simulate the generated guided wave fields. For non-axisymmetric sources, an important angular profile feature is studied. Based on numerical calculations, an angular profile varies with frequency, mode and propagating distance. Since an angular profile determines the energy distribution of the guided waves, the angular profile has a great impact on the pipe inspection capability of guided waves. The simulation of non-axisymmetric angular profiles generated by partialloading is verified by experiments. An angular profile is the superposition of harmonic axisymmetric and non-axisymmetric modes with various phase velocities. A simpler equation is derived to calculate the phase velocities of the non-axisymmetric guided waves and is used for discussing the characteristics of non-axisymmetric guided waves. Angular profiles have many applications in practical pipe testing. The procedure of building desired angular profiles and also angular profile tuning is discussed. This angular profile tuning process is implemented by a phased transducer array and a special computational algorithm. Since a transducer array plays a critical role in guided wave inspection, the performance of a transducer array is discussed in terms of guided wave mode control ability and excitation sensitivity. With time delay inputs, a transducer array is greatly improved for its mode control ability and sensitivity. The algorithms for setting time delays are derived based on frequency, element spacing and phase velocity. With the help of the conclusions drawn on non- axisymmetric guided waves, a phased circumferential partial-loading array is applied to practical pipe testing. The array is used for several specific duties to serve some practical NDE interest: Generation of axisymmetric guided waves, knowledge-based circumferential location estimation and detection of smaller defects. The experiments demonstrate the inspection ability and flexibility of non-axisymmetric guided waves in pipe inspection.

Li, Jian

2001-07-01

277

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...

278

Quantitative evaluation of the SPICE, CMM, ISO 9000 and BOOTSTRAP  

Microsoft Academic Search

This paper comparatively analyses the current models for software process assessment and improvement (SPA\\/SPI) e.g., SPICE, CMM, ISO 9000 and BOOTSTRAP. The configuration of the sample spaces and the partially overlapped fundamental process activities defined in the four models are quantitatively analysed and contrasted. The features, orientation, profile and correlation in the software process capability determination frameworks of the current

Y. Wang; I. Court; M. Ross; G. Staples; G. King; A. Dorling

1997-01-01

279

Qualitative and quantitative physical land evaluation: an operational approach  

Microsoft Academic Search

Physical land evaluation methods are crucial for evaluating potentials and constraints of land for intended land use. Physical resources, such as soil, climate, hydrology, and topography are evaluated. Different technical procedures are used for physical land evaluation ranging from simple methods based on expert knowledge to more complex methods based on simulation models. The expert knowledge is derived from farmers'

Lanen van H. A. J

1991-01-01

280

Nondestructive Test Probe  

NASA Technical Reports Server (NTRS)

Under the Aircraft Structural Integrity program, Langley Research Center invented a device to detect fatigue cracks in aluminum alloy plates. Krautkramer Branson obtained an exclusive license and commercialized a hand-held device, the "CrackFinder," an electromagnetic probe for nondestructive evaluation, used to scan aircraft skins for surface breaks. The technology involves an eddy current, which is an electrical current induced by an alternating magnetic field. The CrackFinder also employs an innovative self-nulling feature, where the device automatically recalibrates to zero so that each flaw detected produces a reading. Compared to conventional testing systems, the CrackFinder is affordable, small, simple to use, and needs no calibration.

1996-01-01

281

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

282

Quantitative evaluation of bioturbation on the deep sea floor  

E-print Network

1975 ABS TRACT Quantitative Fvaluation of Bioturbation on the Deep Sea Floor (Hay 1975) Norman Louis Guinasso, Jr. , B. A. , San . Jose State College Chairman of Advisory Committee: Professor Robert O. Reid Biological mixing in deep-sea sediments... of time. The characteristic propert. ies of the solution are dependent on the dimensionless parameter, D/Lv, where v is the sedimentation rate. lf D/Lv is greater than 10, the surface layer becomes homogeneous, and the model is identical...

Guinasso, Norman Louis

2012-06-07

283

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

284

Light Water Reactor Sustainability (LWRS) Program – Non-Destructive Evaluation (NDE) R&D Roadmap for Determining Remaining Useful Life of Aging Cables in Nuclear Power Plants  

SciTech Connect

The purpose of the non-destructive evaluation (NDE) R&D Roadmap for Cables is to support the Materials Aging and Degradation (MAaD) R&D pathway. The focus of the workshop was to identify the technical gaps in detecting aging cables and predicting their remaining life expectancy. The workshop was held in Knoxville, Tennessee, on July 30, 2012, at Analysis and Measurement Services Corporation (AMS) headquarters. The workshop was attended by 30 experts in materials, electrical engineering, U.S. Nuclear Regulatory Commission (NRC), U.S. Department of Energy (DOE) National Laboratories (Oak Ridge National Laboratory, Pacific Northwest National Laboratory, Argonne National Laboratory, and Idaho National Engineering Laboratory), NDE instrumentation development, universities, commercial NDE services and cable manufacturers, and Electric Power Research Institute (EPRI). The motivation for the R&D roadmap comes from the need to address the aging management of in-containment cables at nuclear power plants (NPPs).

Simmons, Kevin L.; Ramuhalli, Pradeep; Brenchley, David L.; Coble, Jamie B.; Hashemian, Hash; Konnik, Robert; Ray, Sheila

2012-09-14

285

Light Water Reactor Sustainability (LWRS) Program – Non-Destructive Evaluation (NDE) R&D Roadmap for Determining Remaining Useful Life of Aging Cables in Nuclear Power Plants  

SciTech Connect

Executive Summary [partial] The purpose of the non-destructive evaluation (NDE) R&D Roadmap for Cables is to support the Materials Aging and Degradation (MAaD) R&D pathway. A workshop was held to gather subject matter experts to develop the NDE R&D Roadmap for Cables. The focus of the workshop was to identify the technical gaps in detecting aging cables and predicting their remaining life expectancy. The workshop was held in Knoxville, Tennessee, on July 30, 2012, at Analysis and Measurement Services Corporation (AMS) headquarters. The workshop was attended by 30 experts in materials, electrical engineering, and NDE instrumentation development from the U.S. Nuclear Regulatory Commission (NRC), U.S. Department of Energy (DOE) National Laboratories (Oak Ridge National Laboratory, Pacific Northwest National Laboratory, Argonne National Laboratory, and Idaho National Engineering Laboratory), universities, commercial NDE service vendors and cable manufacturers, and the Electric Power Research Institute (EPRI).

Simmons, K.L.; Ramuhali, P.; Brenchley, D.L.; Coble, J.B.; Hashemian, H.M.; Konnick, R.; Ray, S.

2012-09-01

286

Advanced NDE techniques for quantitative characterization of aircraft  

NASA Technical Reports Server (NTRS)

Recent advances in nondestructive evaluation (NDE) at NASA Langley Research Center and their applications that have resulted in quantitative assessment of material properties based on thermal and ultrasonic measurements are reviewed. Specific applications include ultrasonic determination of bolt tension, ultrasonic and thermal characterization of bonded layered structures, characterization of composite materials, and disbonds in aircraft skins.

Heyman, Joseph S.; Winfree, William P.

1990-01-01

287

Quantitative and Qualitative Evaluation of Social Studies Textbook Content.  

ERIC Educational Resources Information Center

A model of social studies textbook analysis and evaluation is developed in this paper and is applied to the analysis and evaluation of the content on Hawaii in selected elementary school social studies textbooks. Innovative methods of content analysis and evaluation of textbook presentations were developed and applied to the subject of Hawaii to…

Suh, Bernadyn K.

288

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

289

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

290

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

291

Noncontact nondestructive tests  

Microsoft Academic Search

Methods developed for noncontact nondestructive tests are reviewed. These tests were developed to improve the applicability of nondestructive tests, which were constrained to the use of sensors and contacts. The techniques applied involve ultrasonic waves for lasers, optical interferometry, thermography, and Compton effect x-ray analysis. The following topics are presented: holographic pattern, holographic reconstruction, source laser, technical holographic inspection methods,

M. Alvaro; F. J. Moreno; J. M. Martindebernardo; V. Cortes

1992-01-01

292

Shearography in Experimental Mechanics and Nondestructive Testing  

NASA Astrophysics Data System (ADS)

This paper reviews shearography and its applications in experimental mechanics and nondestructive testing. Shearography is an interferometric method for measuring surface displacement derivatives. Unlike holography, it does not require special vibration isolation; hence it can be employed in field/factory environments. The technique has already received wide industrial acceptance for nondestructive testing. Other applications include strain measurement, material characterization, residual stress evaluation, vibration studies and 3D shape measurement.

Hung, Y. Y.

293

Quantitative Evaluation of Web Site Content and Structure.  

ERIC Educational Resources Information Center

Describes an approach to automatically classify and evaluate publicly accessible World Wide Web sites. Outlines a research methodology for model building and validation, develops a set of criteria for classifying Web sites, and compares manual versus automated evaluation. (Author/LRW)

Bauer, Christian; Scharl, Arno

2000-01-01

294

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

295

A Systematic Quantitative-Qualitative Model: How To Evaluate Professional Services  

ERIC Educational Resources Information Center

The proposed evaluation model provides for the assignment of relative weights to each criterion, and establishes a weighting system for calculating a quantitative-qualitative raw score for each service activity of a faculty member being reviewed. (Author)

Yoda, Koji

1973-01-01

296

A chromatographic procedure for semi-quantitative evaluation of caseinphosphopeptides in cheese  

Microsoft Academic Search

Caseinphosphopeptides (CPPs) are phosphorylated fragments of caseins, which are found in dairy products. One of their unique\\u000a features is their ability to bind calcium. There are several published methods to extract CPPs from cheese, but none allows\\u000a their quantitative evaluation. A chromatographic procedure allowing a semi-quantitative evaluation of cheese CPPs was adapted\\u000a from a previously published method and tested on

Coralie Dupas; Isabelle Adt; Amandine Cottaz; Rachel Boutrou; Daniel Molle; Julien Jardin; Thierry Jouvet; Pascal Degraeve

2009-01-01

297

Online versus Paper Evaluations: Differences in Both Quantitative and Qualitative Data  

ERIC Educational Resources Information Center

This study sought to determine if differences exist in the quantitative and qualitative data collected with paper and online versions of a medical school clerkship evaluation form. Data from six-and-a-half years of clerkship evaluations were used, some collected before and some after the conversion from a paper to an online evaluation system. The…

Burton, William B.; Civitano, Adele; Steiner-Grossman, Penny

2012-01-01

298

Method for Quantitatively Evaluating the Lateralization of Linguistic Function Using Functional MR Imaging  

Microsoft Academic Search

BACKGROUND AND PURPOSE: Various methods for evaluating the lateralization of lin- guistic function using functional MR imaging have been proposed. However, the optimal meth- od remains controversial. The purpose of this study was not only to establish a method for quantitatively evaluating the lateralization of linguistic function but also to evaluate its optimality. METHODS: Internal speech tasks were measured by

Shun-ichi Nagata; Koichi Uchimura; Wataru Hirakawa; Jun-ichi Kuratsu

2001-01-01

299

Design for manufacturability: quantitative measures for design evaluation  

E-print Network

the application of the methodology to a specific domain. Two examples are given to demonstrate how this theory can help designers create cost efficient designs. The ability to integrate expert knowledge into the evaluation makes the methodology particularly...

Polisetty, Francis Showry Kumar

2012-06-07

300

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

301

A Quantitative Investigation of Stakeholder Variation in Training Program Evaluation.  

ERIC Educational Resources Information Center

A survey was conducted to investigate variation in stakeholder perceptions of training results and evaluation within the context of a high-technology product development firm (the case organization). A scannable questionnaire survey booklet was developed and scanned data were exported and analyzed. Based on an achieved sample of 280 (70% response…

Michalski, Greg V.

302

Research on the quantitative evaluation system for unmanned ground vehicles  

Microsoft Academic Search

The first Chinese unmanned ground vehicles competition - The 2009 Future Challenge: Intelligent Vehicles and Beyond (FC'09) pushed China's unmanned vehicles out of laboratories and into application environments. In order to further promote the development of unmanned vehicle technologies, the test and evaluation system for unmanned vehicles needs to be studied. The design method of test environment is proposed in

Guangming Xiong; Xijun Zhao; Haiou Liu; Shaobin Wu; Jianwei Gong; Haojie Zhang; Huachun Tan; Huiyan Chen

2010-01-01

303

Review article Non-invasive and quantitative evaluation  

E-print Network

by pharmacokinetic analysis of creatine kinase release HP Lefebvre V Laroute, JP Braun, V Lassourd PL Toutain Unité of creatine kinase (CK) release from muscle, is proposed for the evaluation of post-injection muscle damage tolerance / creatine kinase / pharmacokinetics I animal welfare *Correspondence and reprints #12;Résumé

Paris-Sud XI, Université de

304

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

305

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

306

Skin moisturization by hydrogenated polyisobutene--quantitative and visual evaluation.  

PubMed

Hydrogenated polyisobutene (HP) is used in topically applied cosmetic/personal care formulations as an emollient that leaves a pleasing skin feel when applied, and rubbed in after application. This effect, although distinguishable to the user, is difficult to define and quantify. Recognizing that some of the physical properties of HP such as film formation and wear resistance may contribute, in certain mechanisms, to skin moisturization, we designed a short-term pilot study to follow changes in skin moisturization. HP's incorporation into an o/w emulsion at 8% yielded increased viscosity and reduced emulsion droplet size as compared to the emollient ester CCT (capric/caprylic triglyceride) or a control formulation. Quantitative data indicate that application of the o/w emulsion formulation containing either HP or CCT significantly elevated skin moisture content and thus reduced transepidermal water loss (TEWL) by a maximal approximately 33% against the control formulation within 3 h and maintained this up to 6 h. Visual observation of skin treated with the HP-containing formulation showed fine texture and clear contrast as compared to the control or the CCT formulation, confirming this effect. As a result of increased hydration, skin conductivity, as measured in terms of corneometer values, was also elevated significantly by about tenfold as early as 20 min after HP or CCT application and was maintained throughout the test period. Throughout the test period the HP formulation was 5-10% more effective than the CCT formulation both in reduction of TEWL as well as in increased skin conductivity. Thus, compared to the emollient ester (CCT), HP showed a unique capability for long-lasting effect in retaining moisture and improving skin texture. PMID:19296892

Dayan, Nava; Sivalenka, Rajarajeswari; Chase, John

2009-01-01

307

Photoacoustic microscopy for quantitative evaluation of angiogenesis inhibitor  

NASA Astrophysics Data System (ADS)

We present the photoacoustic microscopy (PAM) for evaluation of angiogenesis inhibitors on a chick embryo model. Microvasculature in the chorioallantoic membrane (CAM) of the chick embryos was imaged by PAM, and the optical microscopy (OM) images of the same set of CAMs were also acquired for comparisons, serving for validation of the results from PAM. The angiogenesis inhibitors, Sunitinib, with different concentrations applied to the CAM result in the change in microvascular density, which was quantified by both PAM and OM imaging. Similar change in microvascular density from PAM and OM imaging in response to angiogenesis inhibitor at different doses was observed, demonstrating that PAM has potential to provide objective evaluation of anti-angiogenesis medication. Besides, PAM is advantageous in three-dimensional and functional imaging compared with OM so that the emerging PAM technique may offer unique information on the efficacy of angiogenesis inhibitors and could benefit applications related to antiangiogenesis treatments.

Chen, Sung-Liang; Burnett, Joseph; Sun, Duxin; Xie, Zhixing; Wang, Xueding

2014-03-01

308

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

309

Quantitative vertebral compression fracture evaluation using a height compass  

NASA Astrophysics Data System (ADS)

Vertebral compression fractures can be caused by even minor trauma in patients with pathological conditions such as osteoporosis, varying greatly in vertebral body location and compression geometry. The location and morphology of the compression injury can guide decision making for treatment modality (vertebroplasty versus surgical fixation), and can be important for pre-surgical planning. We propose a height compass to evaluate the axial plane spatial distribution of compression injury (anterior, posterior, lateral, and central), and distinguish it from physiologic height variations of normal vertebrae. The method includes four steps: spine segmentation and partition, endplate detection, height compass computation and compression fracture evaluation. A height compass is computed for each vertebra, where the vertebral body is partitioned in the axial plane into 17 cells oriented about concentric rings. In the compass structure, a crown-like geometry is produced by three concentric rings which are divided into 8 equal length arcs by rays which are subtended by 8 common central angles. The radius of each ring increases multiplicatively, with resultant structure of a central node and two concentric surrounding bands of cells, each divided into octants. The height value for each octant is calculated and plotted against octants in neighboring vertebrae. The height compass shows intuitive display of the height distribution and can be used to easily identify the fracture regions. Our technique was evaluated on 8 thoraco-abdominal CT scans of patients with reported compression fractures and showed statistically significant differences in height value at the sites of the fractures.

Yao, Jianhua; Burns, Joseph E.; Wiese, Tatjana; Summers, Ronald M.

2012-03-01

310

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

311

Evaluation of respirator fit training by quantitative fit testing  

E-print Network

was to evaluate the effect-iveness of a respirator use training program in terms of actual fac piece fit before and after training. Two groups of volunteer test subjects were quartitatively fit tested with half-mask respirators at three po1nts in time. One... group received training in respirator use and fittina techniques. The other group did not rece1ve any training. None of the test subjects had any prior experience with half-mask respirators before their participation in this project. The raw data...

Chute, Daniel Otis

2012-06-07

312

Object-oriented fault tree evaluation program for quantitative analyses  

NASA Technical Reports Server (NTRS)

Object-oriented programming can be combined with fault free techniques to give a significantly improved environment for evaluating the safety and reliability of large complex systems for space missions. Deep knowledge about system components and interactions, available from reliability studies and other sources, can be described using objects that make up a knowledge base. This knowledge base can be interrogated throughout the design process, during system testing, and during operation, and can be easily modified to reflect design changes in order to maintain a consistent information source. An object-oriented environment for reliability assessment has been developed on a Texas Instrument (TI) Explorer LISP workstation. The program, which directly evaluates system fault trees, utilizes the object-oriented extension to LISP called Flavors that is available on the Explorer. The object representation of a fault tree facilitates the storage and retrieval of information associated with each event in the tree, including tree structural information and intermediate results obtained during the tree reduction process. Reliability data associated with each basic event are stored in the fault tree objects. The object-oriented environment on the Explorer also includes a graphical tree editor which was modified to display and edit the fault trees.

Patterson-Hine, F. A.; Koen, B. V.

1988-01-01

313

Evaluating Learning Style Personalization in Adaptive Systems: Quantitative Methods and Approaches  

Microsoft Academic Search

It is a widely held assumption that learning style is a useful model for quantifying user characteristics for effective personalized learning. We set out to challenge this assumption by discussing the current state of the art, in relation to quantitative evaluations of such systems and also the methodologies that should be employed in such evaluations. We present two case studies

Elizabeth J. Brown; Timothy J. Brailsford; Tony Fisher; Adam Moore

2009-01-01

314

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

E-print Network

or interpretation procedures), however only a few studies have been dedicated to the evaluation of the visualization of the values. Our study is devoted to the evaluation of the quantitative visualization of these signals in a particular medical application, the clinical epilepsy studies. In this medical field, 3D representations

Paris-Sud XI, Université de

315

Improved field experimental designs and quantitative evaluation of aquatic ecosystems  

SciTech Connect

The paired-station concept and a log transformed analysis of variance were used as methods to evaluate zooplankton density data collected during five years at an electrical generation station on Lake Michigan. To discuss the example and the field design necessary for a valid statistical analysis, considerable background is provided on the questions of selecting (1) sampling station pairs, (2) experimentwise error rates for multi-species analyses, (3) levels of Type I and II error rates, (4) procedures for conducting the field monitoring program, and (5) a discussion of the consequences of violating statistical assumptions. Details for estimating sample sizes necessary to detect changes of a specified magnitude are included. Both statistical and biological problems with monitoring programs (as now conducted) are addressed; serial correlation of successive observations in the time series obtained was identified as one principal statistical difficulty. The procedure reduces this problem to a level where statistical methods can be used confidently. 27 references, 4 figures, 2 tables.

McKenzie, D.H.; Thomas, J.M.

1984-05-01

316

Invited Chapter in Automation, Miniature Robotics and Sensors for Non-Destructive Testing and Evaluation, Y. Bar-Cohen Editor, April 99  

E-print Network

Invited Chapter in Automation, Miniature Robotics and Sensors for Non-Destructive Testing...........................................................................................................................2 5.1.2.1.2 Advantages - Disadvantages...........................................................................................................................4 5.1.2.2.2 Advantages - Disadvantages

Mavroidis, Constantinos

317

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

318

From Dsm to 3d Building Models: a Quantitative Evaluation  

NASA Astrophysics Data System (ADS)

The paper reviews the state-of-the-art in 3D city models and building block generation, with a description of the most common solutions and approaches. Then the digital reconstruction and comparison of LoD1 and LoD2 building models obtained with commercial packages and using different input data are presented. As input data, a DSM at 1m resolution derived from a GeoEye-1 stereo-pair, a DSM from an aerial block at 50 cm GSD and a LiDAR-based DSM at 1 m resolution are used. The geometric buildings produced with each dataset are evaluated with respect to some ground-truth measurements but also compared between them. Problems such as the quality of the input DSM, the accuracy of the necessary vector datasets containing the building footprints, the flexibility of the approaches and the potentialities of each dataset will be discussed. As reconstruction of the building models is largely influenced by the quality of the building footprints, which may be out-of-date or slightly shifted with respect to the employed DSMs/DTMs, an in-house method is being developed to derive them starting from the produced DSMs.

Macay Moreia, J. M.; Nex, F.; Agugiaro, G.; Remondino, F.; Lim, N. J.

2013-05-01

319

Quantitative investigation into methods for evaluating neocortical slice viability  

PubMed Central

Background In cortical and hippocampal brain slice experiments, the viability of processed tissue is usually judged by the amplitude of extracellularly-recorded seizure-like event (SLE) activity. Surprisingly, the suitability of this approach for evaluating slice quality has not been objectively studied. Furthermore, a method for gauging the viability of quiescent tissue, in which SLE activity is intentionally suppressed, has not been documented. In this study we undertook to address both of these matters using the zero-magnesium SLE model in neocortical slices. Methods Using zero-magnesium SLE activity as the output parameter, we investigated: 1) changes in the pattern (amplitude, frequency and length) of SLE activity as slice health either deteriorated; or was compromised by altering the preparation methodology and; 2) in quiescent tissue, whether the triggering of high frequency field activity following electrode insertion predicted subsequent development of SLE activity — and hence slice viability. Results SLE amplitude was the single most important variable correlating with slice viability, with a value less than 50 ?V indicative of tissue unlikely to be able to sustain population activity for more than 30–60 minutes. In quiescent slices, an increase in high frequency field activity immediately after electrode insertion predicted the development of SLE activity in 100% of cases. Furthermore, the magnitude of the increase in spectral power correlated with the amplitude of succeeding SLE activity (R2 40.9%, p?

2013-01-01

320

Development of nondestructive-evaluation techniques for high-temperature ceramic heat-exchanger components. Fourth annual report, October 1980-September 1981  

SciTech Connect

An assessment has been made of ultrasonic techniques developed to date for nondestructive evaluation of SiC heat-exchanger tubes. The results suggest that ultrasonic inspection is a useful and valuable technique for inspecting these tubes, including ceramic butt joints. However, this method alone is currently not sufficiently effective to detect all critical flaws because of (a) the difficulties in following the surface of an out-of-round tube; (b) the high velocity and thus the large angle of refraction of sound in SiC, which for small-diameter tubes leads to significant beam distortion; and (c) insuffient resolution, relative to the small critical flaw size in ceramics, at conventional ultrasonic testing frequencies. The experiments show that higher frequencies (up to 35 MHz) are required for effective wall-thickness measurements and detection of laminar-type flaws. While acoustic microscopy techniques for flaw and material characterization and holographic interferometry for crack sizing can be used for preservice inspection, in-service inspection of heat-exchanger tubes will probably be limited to ultrasonic inspection from the bore side. Acoustic microscopy (for flaw and material characterization) and holographic interferometry (for crack sizing), although not adaptable to boreside inspection, were shown to be effective as complementary or confirmatory techniques when used in conjunction with conventional ultrasonic testing. Preliminary results employing the microfocus radiogaphy technique have indicated that this method is more sensitive than conventional radiographic techniques for ceramic butt joint assessment.

Kupperman, D.S.; Yuhas, D.

1982-01-01

321

Evaluation of four genes in rice for their suitability as endogenous reference standards in quantitative PCR.  

PubMed

The genetically modified (GM) food/feed quantification depends on the reliable detection systems of endogenous reference genes. Currently, four endogenous reference genes including sucrose phosphate synthase (SPS), GOS9, phospholipase D (PLD), and ppi phosphofructokinase (ppi-PPF) of rice have been used in GM rice detection. To compare the applicability of these four rice reference genes in quantitative PCR systems, we analyzed the target nucleotide sequence variation in 58 conventional rice varieties from various geographic and phylogenic origins, also their quantification performances were evaluated using quantitative real-time PCR and GeNorm analysis via a series of statistical calculation to get a "M value" which is negative correlation with the stability of genes. The sequencing analysis results showed that the reported GOS9 and PLD taqman probe regions had detectable single nucleotide polymorphisms (SNPs) among the tested rice cultivars, while no SNPs were observed for SPS and ppi-PPF amplicons. Also, poor quantitative performance was detectable in these cultivars with SNPs using GOS9 and PLD quantitative PCR systems. Even though the PCR efficiency of ppi-PPF system was slightly lower, the SPS and ppi-PPF quantitative PCR systems were shown to be applicable for rice endogenous reference assay with less variation among the C(t) values, good reproducibility in quantitative assays, and the low M values by the comprehensive quantitative PCR comparison and GeNorm analysis. PMID:20961039

Wang, Chong; Jiang, Lingxi; Rao, Jun; Liu, Yinan; Yang, Litao; Zhang, Dabing

2010-11-24

322

Irradiation of an elastic plate by a finite-amplitude sound beam with applications to nondestructive evaluation  

NASA Astrophysics Data System (ADS)

This dissertation describes an investigation of nonlinear effects associated with the interaction of ultrasound with plates. The overriding goal is to assess the potential for using immersion techniques to measure the nonlinear acoustical parameters of plates. Three measurement configurations are described, with both theory and experiment reported. Effects of weak nonlinearity are included in the theoretical models. In the first configuration, the goal is to characterize the nonlinear elastic response of an isotropic, homogeneous plate. Plate resonances were used to enhance the nonlinear acoustical response. An experiment was performed with an aluminum plate in water, but nonlinearity due to wave propagation in the plate could not be distinguished from the nonlinear effects associated with propagation of sound through the surrounding fluid. In the second configuration, the interaction of ultrasound with bonded plates is considered. In the theoretical model, nonlinear effects are assumed to occur only at the bond. Particular attention is paid to changes in the reflection and transmission coefficients, as well as the second harmonic radiated from the plate, as a function of bond stiffness. Experiments were performed using bonded aluminum and acrylic plates. Measurements are in qualitative agreement with linear theory, but nonlinear effects at the bond were not observed. In the first two configurations, nonlinearity within the plate is taken into account, but not diffraction of the ultrasound beams. In the third configuration, the interaction of a sound beam with a plate at oblique incidence is examined. Here, beam diffraction is taken into account, but plate nonlinearity is considered to be negligible. The theoretical model is based on an angular spectrum method, and accounts for Lamb wave propagation within the plate. At Lamb excitation angles, nonspecular effects occur in the reflected and transmitted sound beams. Second harmonic generation is assumed to occur only in the fluid. Experiments were performed on an aluminum plate in water, and quantitative agreement is found between theory and measurements.

Younghouse, Steven Joseph

323

Quantitative evaluation of regional vegetation ecological environment quality by using remotely sensed data over Qingjiang, Hubei  

NASA Astrophysics Data System (ADS)

Vegetation cover is an important component and the best indication to the region ecological environment. The paper adopts a new method of integrating remote sensing technology and composite index appraisal model based multiple linear regression for quantitatively evaluating the regional vegetation ecological environment quality(VEEQ). This method is different to the traditional ecological environment research methods. It fully utilizes the advantages of quantitatively remote sensing technology, directly extracts the key influencing factors of VEEQ, such as vegetation indices (RVI, NDVI, ARVI, TMG), humidity indices(NDMI, MI, TMW), soil and landform indices(NDSI, TMB, GRABS) as the evaluating parameters from data the Landsat 5/TM remotely sensed images, and then puts these factors mentioned above into the multiple linear regression evaluating model. Ultimately we obtain the VEEQ evaluation rank figure of the experimental field-part of Qingjiang region. The handy multiple linear regression model, is proved to be well fit the experimental field for the vegetation ecological environment evaluation research.

Wang, Cheng; Sun, Yan; Li, Lijun; Zhang, Qiuwen

2007-11-01

324

Artificial weathering and non-destructive tests for the performance evaluation of consolidation materials applied on porous stones  

Microsoft Academic Search

The evaluation of consolidation treatment efficiency in terms of improving the resistance of treated lithotypes to deterioration\\u000a phenomena caused by soluble salts crystallisation, is taking place through dynamic artificial weathering accelerated tests\\u000a of marine salt spray. Quarried biocalcarenites from Greece and Cyprus have been treated with four consolidation materials\\u000a (diversified according to their deposition mechanism). The materials applied are colloidal

A. Moropoulou; G. Haralampopoulos; Th. Tsiourva; F. Auger; J. M. Birginie

2003-01-01

325

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

326

Use of quantitative microbial risk assessment for evaluation of the benefits of laundry sanitation  

Microsoft Academic Search

The goal of this study was to evaluate the risk assessment process for quantifying the contribution of contamination in the home to microbial infections. Whereas risks of enteric pathogens spread through food has been assessed, the spread of fecal-oral pathogens through surfaces likely at low rates would be difficult to address through epidemiologic studies. An alternative is quantitative risk assessment.

LuAnn L. Gibson; Joan B. Rose; Charles N. Haas

1999-01-01

327

Evaluation of a new assay for HBV DNA quantitation in patients with chronic hepatitis B  

Microsoft Academic Search

Background: The Amplicor™ HBV Monitor Test for quantitative determination of serum hepatitis B virus (HBV) DNA has recently been introduced. This assay is based on PCR and a non-radioactive hybridization and detection system on microwell plates.Objective: The performance of the Amplicor™ HBV Monitor Test was evaluated in a routine diagnostic laboratory. The Amplicor™ HBV Monoitor assay was compared to the

Harald H Kessler; Karen Pierer; Elizabeth Dragon; Herwig Lackner; Brigitte Santner; Doris Stünzner; Evelyn Stelzl; Brigitte Waitzl; Egon Marth

1998-01-01

328

QUANTITATIVE PERFORMANCE EVALUATION OF A PEOPLE TRACKING SYSTEM ON A MOBILE ROBOT  

Microsoft Academic Search

Future service robots will need to keep track of the persons in their environment. A number of people tracking systems have been developed for mobile robots, but it is currently impossible to make objective comparisons of their perfor- mance. This paper presents a comprehensive, quantitative evaluation of a state-of-the-art people tracking system for a mobile robot in an office environment,

Grzegorz Cielniak; Andre Treptow; Tom Duckett

329

Evaluation of the Quantitative Cytological Changes in the Epithelium of the Uterine Cervix  

E-print Network

6 5 Evaluation of the Quantitative Cytological Changes in the Epithelium of the Uterine Cervix Sofia 2 Department of Clinical Pathology, Medical University ­ Sofia Abstract: The cytological annually [1]. The cytological gynecological investigation is the basic method for observing the early

Borissova, Daniela

330

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...

331

Agroecosystem Performance Index (API) — A Quantitative Approach to Evaluate the Sustainability of Rice Production Systems  

Microsoft Academic Search

Shifts in agricultural development paradigms to those that incorporate efficiency and sustainability have warranted the need for a comprehensive methodology for evaluating agro-ecosystem performance in terms of its sustainability. The paper describes the Agro-ecosystem Performance Index (API) as a quantitative measure based on the participatory methodological paradigm in the development of sustainability indicators. It was developed by integrating the three

Binoo P. Bonny; R. M. Prasad; Suma Paulose

2010-01-01

332

Evaluation of energy dependency of TDCS method for scattering correction in quantitative SPECT  

Microsoft Academic Search

The transmission-dependent convolution subtraction (TDCS) technique is a promising technique in quantitative SPECT to subtract the scatter components from emission images. Usually a 20% photo-peak energy window is used in SPECT acquisitions. So far no investigation has been done to investigate the effect of energy windows to subtract the scatter components from emission images with the TDCS technique. To evaluate

Hossian M Deloar; Hiroshi Watabe; Kyeong Min Kim; T. Aoi; H. Iida

2002-01-01

333

A Quantitative Evaluation of Payroll Tax Subsidies For Low-Wage Workers  

E-print Network

A Quantitative Evaluation of Payroll Tax Subsidies For Low-Wage Workers : An Equilibrium Search subsidies enhance welfare more than a reduction in the minimum wage when they are spread over a large range (1996)), Phelps (1994) presented a case for a low-wage employment subsidy policy as a means to reduce

Paris-Sud XI, Université de

334

Quantitative evaluation of regional vegetation ecological environment quality by using remotely sensed data over Qingjiang, Hubei  

Microsoft Academic Search

Vegetation cover is an important component and the best indication to the region ecological environment. The paper adopts a new method of integrating remote sensing technology and composite index appraisal model based multiple linear regression for quantitatively evaluating the regional vegetation ecological environment quality(VEEQ). This method is different to the traditional ecological environment research methods. It fully utilizes the advantages

Cheng Wang; Yan Sun; Lijun Li; Qiuwen Zhang

2007-01-01

335

Quantitative evaluation of bulk-diffused metal contamination by lifetime techniques  

Microsoft Academic Search

In this paper we present a systematic comparison among the most common methods (surface photovoltage, Elymat and microwave-detected photoconductive decay) for lifetime measurements. The possibility to identify contaminants and to quantitatively evaluate their concentration by lifetime techniques is investigated. Though these techniques are very different from each other, we show that in relation to bulk-diffused impurities, they agree very well

M. L Polignano; E Bellandi; D Lodi; F Pipia; A Sabbadini; F Zanderigo; G Queirolo; F Priolo

1998-01-01

336

A feature-based metric for the quantitative evaluation of pixel-level image fusion  

Microsoft Academic Search

Pixel-level image fusion has been investigated in various applications and a number of algorithms have been developed and proposed. However, few authors have addressed the problem of how to assess the performance of those algorithms and evaluate the resulting fused images objectively and quantitatively. In this study, two new fusion quality indexes are proposed and implemented through using the phase

Zheng Liu; David S. Forsyth; Robert Laganière

2008-01-01

337

Integrating Qualitative Methods in a Predominantly Quantitative Evaluation: A Case Study and Some Reflections.  

ERIC Educational Resources Information Center

A review of qualitative methods used in a predominantly quantitative evaluation indicates a variety of roles for such a mixing of methods, including framing and revising research questions, assessing the validity of measures and adaptations to program implementation, and gauging the degree of uncertainty and generalizability of conclusions.…

Mark, Melvin M.; Feller, Irwin; Button, Scott B.

1997-01-01

338

A Quantitative Evaluation of 3D Soft Tissue Prediction in Maxillofacial Surgery Planning  

E-print Network

A Quantitative Evaluation of 3D Soft Tissue Prediction in Maxillofacial Surgery Planning S. Zachow1 , Th. Hierl2, and B. Erdmann1 1 Zuse-Institute Berlin (ZIB) 2 Department of Oral-Maxillofacial, Plastic maxillofacial surgeons with an in- tegrated osteotomy planning system for complex bone relocations, facilitating

Andrzejak, Artur

339

Noninvasive, nondestructive approaches to cell bioenergetics.  

PubMed Central

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 (greater than 10:1), and the low phosphate signal from normoxic tissue (approximately 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. Images PMID:6938983

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

1980-01-01

340

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

341

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

342

Development of nondestructive evaluation techniques for high-temperature ceramic heat exchanger components. Eleventh quarterly report, April-June 1980  

SciTech Connect

One of the problems associated with ultrasonic inspection of silicon carbide tubes from the bore side, for wall-thickness measurements or detection of laminar flaws, is the mode conversion of nominally normal-incidence longitudinal waves to shear waves. Under the right circumstances the shear wave can be detected by the transducer after it converts back to a longitudinal wave, and can be confused with a legitimate flaw signal. This phenomenon occurs because of the sharp curvature of the tube and the width of the ultrasonic beam. The effect is discussed in some detail in the present report; reducing the width of the ultrasonic beam to approx. 1 mm is shown to virtually eliminate the problem while not reducing the signal amplitude of the backwall echoes significantly (i.e., by > 5 dB). Infrared techniques have been applied to inspection of glass-adhesive overlap joints in silicon carbide tubes. The results suggest that infrared techniques may be employed successfully in characterizing ceramic overlap joints through observation of heat-flow patterns. Results of previous efforts had led to the conclusion that holographic interferometry, although sensitive to surface flaws, would be difficult to use as a general inspection method for ceramic materials. This technique needs to be reassessed with respect to ceramic joints for two reasons. One is that the irregular geometry of many joints makes ultrasonic signal interpretation difficult, but leaves open the possibility of detecting flaws indirectly by looking for regions of high strain. The other reason for a new look at holography is that the introduction of a television camera and videotape system has made the production and evaluation of holographic interferograms much easier.

Not Available

1980-08-01

343

Holographic nondestructive testing  

Microsoft Academic Search

Holographic nondestructive testing (HNDT) is a high sensitivity, full field, noncontact, optical technique for observing the changes in the surface of a part as it deforms under stress. The stress can arise from the minute application of heat, pressure, torque, or vibration. The information obtained can be used as a design aid to locate and quantify areas undergoing strain and

D. Rosenthal; J. Trolinger

1995-01-01

344

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

345

Holographic techniques for nondestructive testing of tires  

Microsoft Academic Search

Holographic interferometric techniques were used to evaluate the feasibility of the technique in the nondestructive testing (NDT) of commercial automobile tires. Passenger tires with built-in defects were holographically inspected to determine the types of tire defects that can be detected using this method. Separations and voids were located reliably. Defects other than separations and voids were detected in some cases.

H. L. Ceccon

1972-01-01

346

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

Federal Register 2010, 2011, 2012, 2013

...Quantitatively Evaluate the Benefits and Risks of Vaccines: A Technical Workshop; Public Workshop...Quantitatively Evaluate the Benefits and Risks of Vaccines: A Technical Workshop.'' The purpose...and risks of a hypothetical influenza vaccine, and to seek from a range of...

2012-07-17

347

Quantitative microleakage evaluation around amalgam restorations with different treatments on cavity walls.  

PubMed

The purpose of this in vitro study was to evaluate the dye penetration around amalgam restorations in dentin cavities by a quantitative test. Standardized circular cavities were prepared on the facial surface of 75 extracted human single-rooted teeth, and restored with dental amalgam. Different bonding/sealing treatments were used on the cavity walls before the restorations were placed. The specimens were thermo-cycled between 5 +/- 2 degrees C and 55 +/- 2 degrees C for 500 cycles with 1-minute dwell times, followed by immersion in a 2% methylene blue solution for 12 hours at 37 degrees C. The quantitative microleakage was evaluated by spectrophotometry and was expressed by microgram dye per tooth structure. The results showed that the use of bonded amalgam restorations was more effective in reducing microleakage. PMID:10823067

de Morais, P M; Rodrigues Júnior, A L; Pimenta, L A

1999-01-01

348

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

349

Quantitative Evaluation of the Effectiveness of Idea Generation in the Wild  

Microsoft Academic Search

\\u000a New ideas are the primary building blocks in attempts to produce novel interactive technology. Numerous idea generation methods\\u000a such as Brainstorming have been introduced to support this process, but there is mixed evidence regarding their effectiveness.\\u000a In this paper we describe an experimental, quantitative methodology from the domain of product design research for evaluating\\u000a different idea generation methods. We present

Lassi A. Liikkanen; Matti M. Hämäläinen; Anders Häggman; Tua Björklund; Mikko P. Koskinen

350

Synthesis, antioxidant evaluation, and quantitative structure–activity relationship studies of chalcones  

Microsoft Academic Search

Synthesis, antioxidant activity, and quantitative structure–activity relationship (QSAR) of 25 of chalcone derivatives is\\u000a reported here. They were synthesized by Claisen–Schmidt reaction and were characterized by FTIR, NMR, and mass spectroscopy.\\u000a Antioxidant activity is evaluated through four different methods namely, superoxide radical-scavenging, hydrogen peroxide\\u000a scavenging, reducing power, and DPPH radical-scavenging assays. Generally, compounds with –SCH3 and –OCH3 in the para

P. M. Sivakumar; P. K. Prabhakar; M. Doble

2011-01-01

351

Quantitative evaluation by minisequencing and microarrays reveals accurate multiplexed SNP genotyping of whole genome amplified DNA  

Microsoft Academic Search

Whole genome amplification (WGA) procedures such as primer extension preamplification (PEP) or multiple displacement amplification (MDA) have the potential to provide an unlimited source of DNA for large-scale genetic studies. We have performed a quantitative evaluation of PEP and MDA for geno- typing single nucleotide polymorphisms (SNPs) using multiplex, four-color fluorescent minisequen- cing in a microarray format. Forty-five SNPs were

Lovisa Lovmar; Mona Fredriksson; Ulrika Liljedahl; Snaevar Sigurdsson; Ann-Christine Syvanen

2003-01-01

352

Quantitative evaluation of fracture, healing and re-healing of a reversibly cross-linked polymer  

Microsoft Academic Search

The repeated fracture–healing characteristics of 2MEP4F polymer, a cross-linked polymer based on Diels–Alder cycloaddition, are systematically and quantitatively evaluated using a sample geometry that allows for controlled incremental crack growth so that the cracked sample remains in one piece after the test, improving our ability to realign the fracture surfaces prior to healing. The specimens have been pre-cracked to a

Thomas A. Plaisted; Sia Nemat-Nasser

2007-01-01

353

Quantitative Use of the Food Guide Pyramid to Evaluate Dietary Intake of College Students  

Microsoft Academic Search

Objectives To evaluate the usefulness of the Food Guide Pyramid as a quantitative tool for assessing nutritional adequacy and quality.Design One-day food records (n=2,489) were assigned food group scores (1 through 5) by two systems. System 1 recorded the number of food groups on a given record that included the minimum number of servings suggested by the Food Guide Pyramid.

LISA K. SCHUETTE; WON O. SONG; SHARON L. HOERR

1996-01-01

354

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

NASA Technical Reports Server (NTRS)

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

Waller, Jess; Saulsberry, Regor

2012-01-01

355

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

356

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

357

Nondestructive Testing Using Shearography  

Microsoft Academic Search

This article reviews shearography and its applications in nondestructive testing. Shearography is an interferometric technique\\u000a for full-field and non-contacting measurement of surface deformation (displacement or displacement derivatives). It was invented\\u000a to overcome some limitations of holographic interferometry by eliminating the reference beam, resulting in having much higher\\u000a tolerance to environmental disturbances. Consequently, shearography can be practiced in a typical industrial

MICHAEL Y. Y. HUNG

358

Quantitative morphologic evaluation of magnetic resonance imaging during and after treatment of childhood leukemia  

PubMed Central

Introduction Medical advances over the last several decades, including CNS prophylaxis, have greatly increased survival in children with leukemia. As survival rates have increased, clinicians and scientists have been afforded the opportunity to further develop treatments to improve the quality of life of survivors by minimizing the long-term adverse effects. When evaluating the effect of antileukemia therapy on the developing brain, magnetic resonance (MR) imaging has been the preferred modality because it quantifies morphologic changes objectively and noninvasively. Method and results Computer-aided detection of changes on neuroimages enables us to objectively differentiate leukoencephalopathy from normal maturation of the developing brain. Quantitative tissue segmentation algorithms and relaxometry measures have been used to determine the prevalence, extent, and intensity of white matter changes that occur during therapy. More recently, diffusion tensor imaging has been used to quantify microstructural changes in the integrity of the white matter fiber tracts. MR perfusion imaging can be used to noninvasively monitor vascular changes during therapy. Changes in quantitative MR measures have been associated, to some degree, with changes in neurocognitive function during and after treatment Conclusion In this review, we present recent advances in quantitative evaluation of MR imaging and discuss how these methods hold the promise to further elucidate the pathophysiologic effects of treatment for childhood leukemia. PMID:17653705

Reddick, Wilburn E.; Laningham, Fred H.; Glass, John O.; Pui, Ching-Hon

2008-01-01

359

Computer-Assisted Quantitative Evaluation of Therapeutic Responses for Lymphoma Using Serial PET/CT Imaging  

PubMed Central

Rationale and Objectives Molecular imaging modalities such as PET/CT have emerged as an essential diagnostic tool for monitoring treatment response in lymphoma patients. However, quantitative assessment of treatment outcomes from serial scans is often difficult, laborious, and time consuming. Automatic quantization of longitudinal PET/CT scans provides more efficient and comprehensive quantitative evaluation of cancer therapeutic responses. This study develops and validates a Longitudinal Image Navigation and Analysis (LINA) system for this quantitative imaging application. Materials and Methods LINA is designed to automatically construct longitudinal correspondence along serial images of individual patients for changes in tumor volume and metabolic activity via regions of interest (ROI) segmented from a given time-point image and propagated into the space of all follow-up PET/CT images. We applied LINA retrospectively to nine lymphoma patients enrolled in an immunotherapy clinical trial conducted at the Center for Cell and Gene Therapy, Baylor College of Medicine. This methodology was compared to the readout by a diagnostic radiologist, who manually measured the ROI metabolic activity as defined by the maximal Standardized Uptake Value (SUVmax). Results Quantitative results showed that the measured SUVs obtained from automatic mapping are as accurate as semi-automatic segmentation and consistent with clinical examination finding. The average of relative squared differences of SUVmax between automatic and semi-automatic segmentation was found to be 0.02. Conclusion These data support a role for LINA in facilitating quantitative analysis of serial PET/CT images to efficiently assess cancer treatment responses in a comprehensive and intuitive software platform. PMID:20060747

Gao, Xin; Xue, Zhong; Xing, Jiong; Lee, Daniel Y.; Gottschalk, Stephen M.; Heslop, Helen H.; Bollard, Catherine M.; Wong, Stephen T.C.

2010-01-01

360

Quantitative evaluation of atherosclerotic plaque phantom by near-infrared multispectral imaging with three wavelengths  

NASA Astrophysics Data System (ADS)

Atherosclerosis is a primary cause of critical ischemic disease. The risk of critical event is involved the content of lipid in unstable plaque. Near-infrared (NIR) range is effective for diagnosis of atherosclerotic plaque because of the absorption peaks of lipid. NIR multispectral imaging (NIR-MSI) is suitable for the evaluation of plaque because it can provide spectroscopic information and spatial image quickly with a simple measurement system. The purpose of this study is to evaluate the lipid concentrations in plaque phantoms quantitatively with a NIR-MSI system. A NIR-MSI system was constructed with a supercontinuum light, a grating spectrometer and a MCT camera. Plaque phantoms with different concentrations of lipid were prepared by mixing bovine fat and a biological soft tissue model to mimic the different stages of unstable plaque. We evaluated the phantoms by the NIR-MSI system with three wavelengths in the band at 1200 nm. Multispectral images were processed by spectral angle mapper method. As a result, the lipid areas of phantoms were effectively highlighted by using three wavelengths. In addition, the concentrations of lipid areas were classified according to the similarity between measured spectra and a reference spectrum. These results suggested the possibility of image enhancement and quantitative evaluation of lipid in unstable plaque with a NIR-MSI.

Nagao, Ryo; Ishii, Katsunori; Awazu, Kunio

2014-03-01

361

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

362

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

363

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

364

Holographic nondestructive testing  

SciTech Connect

Holographic nondestructive testing (HNDT) is a high sensitivity, full field, noncontact, optical technique for observing the changes in the surface of a part as it deforms under stress. The stress can arise from the minute application of heat, pressure, torque, or vibration. The information obtained can be used as a design aid to locate and quantify areas undergoing strain and as a quality control aid to identify structural flaws such as internal flaws or delaminations. HNDT is also used to identify and measure vibrational modes.

Rosenthal, D.; Trolinger, J. [MetroLaser, Irvine, CA (United States)

1995-12-01

365

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

366

Quantitative Evaluation of Paracetamol and Caffeine from Pharmaceutical Preparations Using Image Analysis and RP-TLC  

Microsoft Academic Search

A reversed-phase high-performance thin-layer chromatographic method combined with image analysis was developed and validated\\u000a for simultaneous quantitative evaluation of paracetamol and caffeine in pharmaceutical preparations. RP-HPTLC-W18 chromatographic\\u000a plates were used as the stationary phase and methanol:glacial acetic acid:water (25:4.3:70.7; v:v:v) as the mobile phase. The detection of the spots and the image documentation were carried out under 254 nm UV radiation.

Florin Soponar; Augustin C?t?lin Mo?; Costel Sârbu

2009-01-01

367

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

368

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

NASA Astrophysics Data System (ADS)

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

Koriyama, Atsushi; Yasuhara, Wataru; Hachiya, Hiroyuki

2012-07-01

369

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

370

49 CFR 192.243 - Nondestructive testing.  

Code of Federal Regulations, 2010 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...

2010-10-01

371

49 CFR 192.243 - Nondestructive testing.  

Code of Federal Regulations, 2012 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...

2012-10-01

372

49 CFR 192.243 - Nondestructive testing.  

Code of Federal Regulations, 2011 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...

2011-10-01

373

Quantitative maps of genetic interactions in yeast - Comparative evaluation and integrative analysis  

PubMed Central

Background High-throughput genetic screening approaches have enabled systematic means to study how interactions among gene mutations contribute to quantitative fitness phenotypes, with the aim of providing insights into the functional wiring diagrams of genetic interaction networks on a global scale. However, it is poorly known how well these quantitative interaction measurements agree across the screening approaches, which hinders their integrated use toward improving the coverage and quality of the genetic interaction maps in yeast and other organisms. Results Using large-scale data matrices from epistatic miniarray profiling (E-MAP), genetic interaction mapping (GIM), and synthetic genetic array (SGA) approaches, we carried out here a systematic comparative evaluation among these quantitative maps of genetic interactions in yeast. The relatively low association between the original interaction measurements or their customized scores could be improved using a matrix-based modelling framework, which enables the use of single- and double-mutant fitness estimates and measurements, respectively, when scoring genetic interactions. Toward an integrative analysis, we show how the detections from the different screening approaches can be combined to suggest novel positive and negative interactions which are complementary to those obtained using any single screening approach alone. The matrix approximation procedure has been made available to support the design and analysis of the future screening studies. Conclusions We have shown here that even if the correlation between the currently available quantitative genetic interaction maps in yeast is relatively low, their comparability can be improved by means of our computational matrix approximation procedure, which will enable integrative analysis and detection of a wider spectrum of genetic interactions using data from the complementary screening approaches. PMID:21435228

2011-01-01

374

Nondestructive assay of green HTGR fuel rods  

Microsoft Academic Search

This report describes the nondestructive (NDA) work done at Los Alamos during 1979 and 1980 as part of the New Brunswick Laboratory-sponsored evaluation of NDA of the uranium content of fabricated fuel rods for high-temperature gas-cooled reactors (HTGR). The methods used (delayed neutron and passive gamma ray) are concisely described, and the results are summarized and compared in graphical and

H. H. Barschall; M. M. Meier; J. L. Parker

2010-01-01

375

A computer-aided nondestructive inspection system  

Microsoft Academic Search

Attention is given to a computer-aided nondestructive inspection system designed for improving the speed and quality of the ultrasonic evaluation of diffusion-bonded parts of the B-1B aircraft. The system consists of a host computer, a data acquisition and multi-axis control (DAMAC) system, and a custom mechanical scanning system. The host computer uses menu-driven software to provide a user-friendly interface for

R. C. Addison Jr.; J. M. F. Lee; A. H. Muir Jr.; A. W. Thiele

1986-01-01

376

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

377

Anterior Segment Optical Coherence Tomography for the Quantitative Evaluation of the Anterior Segment Following Boston Keratoprosthesis  

PubMed Central

Objective To quantitatively evaluate the anterior segment using anterior segment optical coherence tomography (AS-OCT) following Boston keratoprosthesis type 1. Methods A retrospective study consisted of AS-OCT imaging at a single time point postoperatively in 52 eyes. Main outcomes measures include anatomical and functional anterior chamber depth (ACD), angle (ACA) and peripheral and proximal synechiae. Results The mean time point of imaging was 19.3 months postoperatively. Average anatomical and functional ACD was 2.0 and 0.21 mm respectively, and mean ACA ranged from 2.5° to 6.14° in representative meridians. An average of 8.7 clock hours of angle closure was observed in the 25 eyes in which all meridians were imaged. The majority of eyes showed peripheral (86.5%) and proximal (67.3%) synechiae. Conclusions AS-OCT is a useful tool for quantitative evaluation of anterior segment and angle after keratoprosthesis, which is otherwise poorly visible. The majority of eyes showed shallow ACD, extensive angle closure and synechiae formation. PMID:23940621

Kang, Joann J.; Allemann, Norma; Vajaranant, Thasarat; de la Cruz, Jose; Cortina, Maria Soledad

2013-01-01

378

A novel quantitative method for evaluating diffuse in-stent narrowing at follow-up angiography.  

PubMed

A new quantitative parameter, diffuse index (DI), was proposed to evaluate objectively whether in-stent restenosis is diffuse or focal in nature. A total of 343 patients (346 lesions) with Wiktor-GX, AVE MS-II, or JOMED stents were evaluated at follow-up angiography. According to the QCA-CMS definition, lesion length is derived from the 100% reference diameter function (RDF). By moving the RDF downward, the lesion length, LL(x), at each percentage x of the RDF can be calculated. We have defined the DI by the ratio of this calculated length LL(x) and the total stent length, SL, in other words, DI = [LL(x)/SL]. The percentage plaque area (% PA) was calculated by dividing the plaque area by the sum of the plaque area and luminal area within the stent. An excellent correlation was found between the DI at 88% RDF and the % PA in all three stents (r > 0.88). The individual correlation curves were nearly identical, independent of the type of stent. Furthermore, based on the overall data, the combination of a DI > 0.8 and % PA > 30% correlated with a high incidence of subsequent major adverse cardiac events (13/25 = 52%). From these data, it can be concluded that the diffuse index is a new objective quantitative parameter to describe whether in-stent restenosis is of focal or diffuse nature. PMID:11747154

Ishii, Y; van Weert, A W; Hekking, E; de Marie, K; ter Horst, J; Oemrawsingh, P V; Reiber, J H

2001-11-01

379

Antiangiogenic effects of pazopanib in xenograft hepatocellular carcinoma models: evaluation by quantitative contrast-enhanced ultrasonography  

PubMed Central

Background Antiangiogenesis is a promising therapy for advanced hepatocellular carcinoma (HCC), but the effects are difficult to be evaluated. Pazopanib (GW786034B) is a pan-vascular endothelial growth factor receptor inhibitor, the antitumor effects or antiangiogenic effects haven't been investigated in HCC. Methods In vitro direct effects of pazopanib on human HCC cell lines and endothelial cells were evaluated. In vivo antitumor effects were evaluated in three xenograft nude mice models. In the subcutaneous HCCLM3 model, intratumoral blood perfusion was detected by contrast-enhanced ultrasonography (CEUS), and serial quantitative parameters were profiled from the time-intensity curves of ultrasonograms. Results In vitro proliferation of various HCC cell lines were not inhibited by pazopanib. Pazopanib inhibited migration and invasion and induced apoptosis significantly in two HCC cell lines, HCCLM3 and PLC/PRF/5. Proliferation, migration, and tubule formation of human umbilical vein endothelial cells were inhibited by pazopanib in a dose-dependent manner. In vivo tumor growth was significantly inhibited by pazopanib in HCCLM3, HepG2, and PLC/PRF/5 xenograft models. Various intratumoral perfusion parameters changed over time, and the signal intensity was significantly impaired in the treated tumors before the treatment efficacy on tumor size could be observed. Mean transit time of the contrast media in hotspot areas of the tumors was reversely correlated with intratumoral microvessel density. Conclusions Antitumor effects of pazopanib in HCC xenografts may owe to its antiangiogenic effects, and the in vivo antiangiogenic effects could be evaluated by quantitative CEUS. PMID:21251271

2011-01-01

380

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

NASA Technical Reports Server (NTRS)

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

Cramer, K. Elliott

2002-01-01

381

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

382

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

NASA Astrophysics Data System (ADS)

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

Montanini, R.; Freni, F.; Rossi, G. L.

2012-09-01

383

Mechanism of variable structural colour in the neon tetra: quantitative evaluation of the Venetian blind model  

PubMed Central

The structural colour of the neon tetra is distinguishable from those of, e.g., butterfly wings and bird feathers, because it can change in response to the light intensity of the surrounding environment. This fact clearly indicates the variability of the colour-producing microstructures. It has been known that an iridophore of the neon tetra contains a few stacks of periodically arranged light-reflecting platelets, which can cause multilayer optical interference phenomena. As a mechanism of the colour variability, the Venetian blind model has been proposed, in which the light-reflecting platelets are assumed to be tilted during colour change, resulting in a variation in the spacing between the platelets. In order to quantitatively evaluate the validity of this model, we have performed a detailed optical study of a single stack of platelets inside an iridophore. In particular, we have prepared a new optical system that can simultaneously measure both the spectrum and direction of the reflected light, which are expected to be closely related to each other in the Venetian blind model. The experimental results and detailed analysis are found to quantitatively verify the model. PMID:20554565

Yoshioka, S.; Matsuhana, B.; Tanaka, S.; Inouye, Y.; Oshima, N.; Kinoshita, S.

2011-01-01

384

Quantitative evaluation of HIV and SIV co-receptor use with GHOST(3) cell assay.  

PubMed

An assay has been established for quantitative evaluation of lentivirus coreceptor use with the help of GHOST(3) cells. GHOST(3) cells were derived from the human osteosarcoma cell line, HOS, and have been engineered to stably express CD4 and one or another of the chemokine receptors CCR3, CCR5, CXCR4, CXCR6/STRL33/Bonzo, or the orphan receptor GPR15/BOB. The indicator cell line carries the HIV-2 long terminal repeat-driven green fluorescence protein (GFP) gene, which becomes activated upon infection with HIV or SIV. Viral entry is followed by Tat activation of transcription and GFP becomes expressed. Infected cells can be detected as early as 2 or 3 d after infection by simple fluorescence microscopic observation. The simplicity of the GHOST(3) cell system makes it particularly suitable for screening of a large number of isolates. In addition, the efficiency of co-receptor use can be accurately quantitated with flow cytometric analysis. Thus, the most efficiently used co-receptor of multitropic isolates can be determined. It is also possible to sensitively determine co-receptor switch of sequential isolates from the same individual. PMID:16061987

Vödrös, Dalma; Fenyö, Eva Maria

2005-01-01

385

Application of the sheepskin mattress in clinical care for pressure relieving: a quantitative experimental evaluation.  

PubMed

This study aimed at quantitatively evaluating the effectiveness of sheepskin mattress (SSM) in pressure relieving, and then variables of peak pressure (mmHg) (PP), average pressure (AP) and contact area (cm(2)) (CA) at the total, back, sacrum and heel regions of 18 students supinely lying in a control mattress (CM), standard hospital mattress (SHM), SHM+SSM, SSM+CM and AM+CM were measured and contrasted. Paired-T test with a significant level of .05 shows that: the intervention of SSM significantly increased the total CA of SHM by 395.6 cm(2) and lowered its PP and AP by 8.8 and 2.0 mmHg respectively; further, the pressure distribution of SSM+CM was superior to that of AM+CM. The reliability of this study, with exception of the heel area, was proven to be good. Overall, the sheepskin mattress is an effective product in pressure reliving. PMID:24411476

Zhou, Jin; Xu, Bo; Tang, Qiuyue; Chen, Wuyong

2014-02-01

386

Development and evaluation of real competitive PCR for high-throughput quantitative applications.  

PubMed

Real competitive PCR (rcPCR) has been shown to have high sensitivity, reproducibility, and high-throughput potential. We describe further development and evaluation of this methodology as a tool for measuring nucleic acid abundance within a cell. Modifications to the original protocol allow analysis of gene expression levels using standard conditions regardless of mRNA abundance and assay type, thereby increasing throughput and ease of reaction setup while decreasing optimization time. In addition, we have developed a software package, TITAN, to automatically analyze the results. The details are relevant to researchers performing competitive PCR using any detection technique. The effectiveness of the described developments is demonstrated using 12 genes known to have differential expression in cell lines grown under normal and hypoxic conditions. Quantitative and qualitative comparisons to real-time PCR are presented. It is also demonstrated that the technique is capable of detecting submicroscopic chromosomal DNA deletions. PMID:15797563

Elvidge, Gareth P; Price, Tom S; Glenny, Louisa; Ragoussis, Jiannis

2005-04-15

387

Quantitative evaluation of electroconvulsive therapy for Parkinson's disease with refractory psychiatric symptoms.  

PubMed

Patients with advanced-stage Parkinson's disease (PD) occasionally experience refractory depression or catatonic stupor. Electroconvulsive therapy (ECT) has been reported as a successful procedure for both severe psychosis and motor symptoms in patients with PD. Four patients with PD who were receiving ECT were quantitatively evaluated using the Unified PD Rating scale part III, Hoehn and Yahr scale, Barthel index, Neuropsychiatric Inventory, mini-mental state examination, Revised Hasegawa's Dementia scale, Beck's Depression Inventory, and Hamilton Rating Scale for Depression-17. We adopted the "half-age" method, which is an age-based stimulus-dosing method. The patients showed improvement in symptoms of psychosis and motor symptoms without any adverse effects. The interval of improvement after ECT varied among patients. Of note, a decrease in psychiatric symptoms successfully alleviated the burden of caregivers. ECT may be useful to treat parkinsonism with refractory psychosis, major depression, or catatonic stupor, within the limitations of the patients enrolled. PMID:24744048

Nishioka, Kenya; Tanaka, Ryota; Shimura, Hideki; Hirano, Kazuoki; Hatano, Taku; Miyakawa, Koichi; Arai, Heii; Hattori, Nobutaka; Urabe, Takao

2014-11-01

388

Evaluation of an imaging biomarker, Dixon quantitative chemical shift imaging, in Gaucher disease: lessons learned.  

PubMed

Gaucher disease (GD) is the first lysosomal storage disorder for which specific therapy became available. The infiltration of bone marrow by storage cells plays an important part in the pathophysiology of skeletal complications and can be quantified by measurements of bone marrow fat fraction (Ff). Ff measurements by Dixon quantitative chemical shift imaging (QCSI) are standard for the follow-up care of GD patients at the Academic Medical Center. Several criteria should be met in order for these measurements to qualify as an imaging biomarker. These include: 1) The presence of the imaging biomarker is closely coupled or linked to the presence of the target disease or condition; 2) The detection and/or quantitative measurement of the biomarker is accurate, reproducible, and feasible over time, and; 3) The changes measured over time in the imaging biomarker are closely coupled, or linked, to the success or failure of the therapeutic effect and the true end point for the medical therapy being evaluated. This review assesses the use of Ff measurements by QCSI as a biomarker for GD in light of these criteria. In addition potential pitfalls are discussed including: degenerative disc disease; vertebral collapse and infection; haematological malignancies; focal fatty deposits; age; menopause; phase and repositioning errors, and; fat surrounding the basivertebral vein.QCSI measurements of Ff can be used as an imaging biomarker for GD taking these pitfalls into account. It is one of the first biomarkers, in particular imaging biomarkers, for GD that has been systematically evaluated and could be a valuable tool in clinical trials comparing different treatments or dosing regimens. PMID:24924293

van Dussen, L; Akkerman, E M; Hollak, C E M; Nederveen, A J; Maas, M

2014-11-01

389

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

SciTech Connect

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 to 16.0 Gy delivered to the tumor bed. Patients underwent scanning with ultrasound during follow-up, which ranged from 6 to 94 months (median, 22 months) postradiotherapy. Conventional ultrasound images and radio-frequency (RF) echo signals were acquired from treated and untreated breasts. Three ultrasound parameters, namely, skin thickness, Pearson coefficient, and spectral midband fit, were computed from RF signals to measure radiation-induced changes in dermis, hypodermis, and subcutaneous tissue, respectively. Ultrasound parameter values of the treated breast were compared with those of the untreated breast. Ultrasound findings were compared with clinical assessment using Radiation Therapy Oncology Group (RTOG) late-toxicity scores. Results: Significant changes were observed in ultrasonic parameter values of the treated vs. untreated breasts. Average skin thickness increased by 27.3%, from 2.05 {+-} 0.22mm to 2.61 {+-} 0.52mm; Pearson coefficient decreased by 31.7%, from 0.41 {+-} 0.07 to 0.28 {+-} 0.05; and midband fit increased by 94.6%, from -0.92 {+-} 7.35 dB to 0.87 {+-} 6.70 dB. Ultrasound evaluations were consistent with RTOG scores. Conclusions: Quantitative ultrasound provides a noninvasive, objective means of assessing radiation-induced changes to the skin and subcutaneous tissue. This imaging tool will become increasingly valuable as we continue to improve radiation therapy technique.

Liu Tian, E-mail: tliu34@emory.ed [Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA (United States); Zhou Jun [Department of Radiation Oncology, Columbia University Medical Center, New York, NY (United States); Yoshida, Emi J. [Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA (United States); Woodhouse, Shermian A. [Department of Radiation Oncology, Columbia University Medical Center, New York, NY (United States); Schiff, Peter B. [Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA (United States); Wang, Tony J.C. [Department of Radiation Oncology, Columbia University Medical Center, New York, NY (United States); Lu Zhengfeng; Pile-Spellman, Eliza [Department of Radiology, Columbia University Medical Center, New York, NY (United States); Zhang Pengpeng [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Kutcher, Gerald J. [Department of History, Binghamton University, Binghamton, NY (United States)

2010-11-01

390

Genome-wide evaluation for quantitative trait loci under the variance component model  

PubMed Central

The identity-by-descent (IBD) based variance component analysis is an important method for mapping quantitative trait loci (QTL) in outbred populations. The interval-mapping approach and various modified versions of it may have limited use in evaluating the genetic variances of the entire genome because they require evaluation of multiple models and model selection. In this study, we developed a multiple variance component model for genome-wide evaluation using both the maximum likelihood (ML) method and the MCMC implemented Bayesian method. We placed one QTL in every few cM on the entire genome and estimated the QTL variances and positions simultaneously in a single model. Genomic regions that have no QTL usually showed no evidence of QTL while regions with large QTL always showed strong evidence of QTL. While the Bayesian method produced the optimal result, the ML method is computationally more efficient than the Bayesian method. Simulation experiments were conducted to demonstrate the efficacy of the new methods. Electronic supplementary material The online version of this article (doi:10.1007/s10709-010-9497-1) contains supplementary material, which is available to authorized users. PMID:20835884

Han, Lide

2010-01-01

391

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

PubMed

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

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

2014-11-01

392

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

PubMed

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

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

2012-01-01

393

Nondestructive Determination of Bond Strength  

NASA Technical Reports Server (NTRS)

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

2000-01-01

394

Quantitative Evaluation of Iranian Radiology Papers and Its Comparison with Selected Countries  

PubMed Central

Background: Recent technological developments in medicine, including modern radiology have promoted the impact of scientific researches on social life. The scientific outputs such as article and patents are products that show the scientists’ attempt to access these achievements. Objectives: In the current study, we evaluate the current situation of Iranian scientists in the field of radiology and compare it with the selected countries in terms of scientific papers. For this purpose, we used scientometric tools to quantitatively assess the scientific papers in the field of radiology. Materials and Methods: Radiology papers were evaluated in the context of medical field audit using retrospective model. We used the related databases of biomedical sciences for extraction of articles related to radiology. In the next step, the situation of radiology scientific products of the country were determined with respect to the under study regional countries. Results: Results of the current study showed a ratio of 0.19% for Iranian papers in PubMed database published in 2009. In addition, in 2009, Iranian papers constituted 0.29% of the Scopus scientific database. The proportion of Iranian papers in the understudy region was 7.6%. Conclusion: To diminish the gap between Iranian scientific radiology papers and other competitor countries in the region and achievement of document 2025 goals, multifold effort of the society of radiology is necessary. PMID:24693301

Ghafoori, Mahyar; Emami, Hasan; Sedaghat, Abdolrasoul; Ghiasi, Mohammad; Shakiba, Madjid; Alavi, Manijeh

2014-01-01

395

Quantitative evaluation of HIV-1 coreceptor use in the GHOST3 cell assay.  

PubMed

The utility of the GHOST(3) cell assay has been evaluated for testing coreceptor use of primary human immunodeficiency virus type 1 (HIV-1) isolates. GHOST(3) cells were derived from the human osteosarcoma cell line, HOS, and have been engineered to stably express CD4 and one or another of the chemokine receptors CCR3, CCR5, CXCR4, Bonzo, or the orphan receptor BOB. The indicator cell line carries the HIV-2 long terminal repeat-driven green fluorescence protein (GFP) gene, which becomes activated upon infection with HIV or simian immunodeficiency virus. Viral entry is followed by Tat activation of transcription and GFP becomes expressed. Infected cells can be detected 2 or 3 days after infection by simple fluorescence microscopic observation. This simplicity is the main advantage of the GHOST(3) cell system and makes it particularly suitable for screening of a large number of isolates. In addition, the efficiency of coreceptor use can be accurately quantitated with flow cytometric analysis. Here, we evaluated the coreceptor use of 59 primary HIV-1 isolates of different subtypes. PMID:11878871

Vödrös, D; Tscherning-Casper, C; Navea, L; Schols, D; De Clercq, E; Fenyö, E M

2001-12-01

396

Quantitative evaluation of the cell penetrating properties of an iodinated Tyr-L-maurocalcine analog.  

PubMed

L-Maurocalcine (L-MCa) is the first reported animal cell-penetrating toxin. Characterizing its cell penetration properties is crucial considering its potential as a vector for the intracellular delivery of drugs. Radiolabeling is a sensitive and quantitative method to follow the cell accumulation of a molecule of interest. An L-MCa analog containing an additional N-terminal tyrosine residue (Tyr-L-MCa) was synthesized, shown to fold and oxidize properly, and successfully radioiodinated to (125)I-Tyr-L-MCa. Using various microscopy techniques, the average volume of the rat line F98 glioma cells was evaluated at 8.9 to 18.9×10(-7)?l. (125)I-Tyr-L-MCa accumulates within cells with a dose-dependency similar to the one previously published using 5,6-carboxyfluorescein-L-MCa. According to subcellular fractionation of F98 cells, plasma membranes keep less than 3% of the peptide, regardless of the extracellular concentration, while the nucleus accumulates over 75% and the cytosol around 20% of the radioactive material. Taking into account both nuclear and cytosolic fractions, cells accumulate intracellular concentrations of the peptide that are equal to the extracellular concentrations. Estimation of (125)I-Tyr-L-MCa cell entry kinetics indicate a first rapid phase with a 5min time constant for the plasma membrane followed by slower processes for the cytoplasm and the nucleus. Once inside cells, the labeled material no longer escapes from the intracellular environment since 90% of the radioactivity remains 24h after washout. Dead cells were found to have a lower uptake than live ones. The quantitative information gained herein will be useful for better framing the use of L-MCa in biotechnological applications. This article is part of a Special Issue entitled: Calcium Signaling in Health and Disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau. PMID:24667409

Tisseyre, Céline; Ahmadi, Mitra; Bacot, Sandrine; Dardevet, Lucie; Perret, Pascale; Ronjat, Michel; Fagret, Daniel; Usson, Yves; Ghezzi, Catherine; De Waard, Michel

2014-10-01

397

Evaluation of a portable x-ray fluorescence survey meter for the quantitative determination of trace metals in welding fumes  

E-print Network

EVALUATION OF A PORTABLE X-RAY FLUORE~ SURVEY METER FOR TIIE QUANTITATIVE DEPERMINATI(gq OF TRACE METALS IN WELDING FIJvtES A THESIS by MARY CATHERINE FEHRENBACHER Submitted to the Graduate College of Texas A%M University in partial... fulfillment of the requirement for the degree of MASTER OF SCIENCE May, 1984 MAJOR SUBJECI': INDUSTRIAL HYGIENE EVALUATION OF A PORTABLE X-RAY FLUORES~ SURVEY METER FOR THE QUANTITATIVE DETERMINATIGN OF TRACE METALS IN WELDING FIJvtES A THESIS by h...

Fehrenbacher, Mary Catherine

2012-06-07

398

Nondestructive Acoustic Imaging Techniques  

NASA Astrophysics Data System (ADS)

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

Schmitz, Volker

399

Quantitative evaluation of iron transport processes in the Sea of Okhotsk  

NASA Astrophysics Data System (ADS)

Comprehensive observations of the iron (Fe) distribution in the western Sea of Okhotsk were conducted and revealed the existence of two Fe transport processes in the sub-polar marginal sea. One transport process is Fe loading from the Amur River and transport by the East Sakhalin Current (ESC), and the other is Fe transport by the intermediate water (part of which was reported by Nishioka et al., 2007). Here, we report on quantitative evaluations of these two Fe transport processes. The surface dissolved Fe (Diss-Fe) and low salinity water distribution clearly indicate the influence of Fe discharge from the Amur River and the Fe that is transported by the East Sakhalin Current. The amounts of total dissolvable Fe (TD-Fe) and Diss-Fe that cross the surface of the northeast Sakhalin coastal area are estimated at 9.0 × 108 ? 1.3 × 109 g yr-1 and 1.0 × 108 ? 1.5 × 108 g yr-1, respectively. Although the ESC surface transport system along the Sakhalin coast is effective, the length-scale estimation of TD-Fe transport indicated that only 1.5% of the Fe at the mouth of the Amur River reached 52°N, which may be due to scavenging by biological particulates. High Fe anomalies were observed at the bottom of the continental shelf and the shelf break along the Sakhalin coast. The extremely low temperature and low N* water indicate that Fe resuspension due to the reducing properties of sediment occurred on the shelf and that the Fe was introduced to Dense Shelf Water (DSW) by tidal mixing. We estimate that the amounts of TD-Fe and Diss-Fe involved in the DSW on the continental shelf are 8.8 × 1010 ? 2.5 × 1011 g yr-1 and 2.3 × 109 ? 6.6 × 109 g yr-1, respectively. Length-scale estimates of TD-Fe transport indicate that 20% of the TD-Fe on the continental shelf remained in the Kuril Basin; thus, the TD-Fe in the intermediate water was efficiently transported to the Kuril Basin. These results indicate that two orders of magnitude more Fe is derived from the continental shelf by the intermediate water than by surface water and that Fe is transported a greater distance by intermediate water than by the surface layer. Additionally, the Fe that reached the Kuril Straits was mixed by intensive tidal mixing and influenced the vertical profiles of the water columns on both sides of the Kuril Straits in the Kuril Basin and the Oyashio region. Our quantitative evaluation also indicates other Fe inputs around the Kuril Strait.

Nishioka, Jun; Nakatsuka, Takeshi; Ono, Kazuya; Volkov, Yu. N.; Scherbinin, Alexey; Shiraiwa, Takayuki

2014-08-01

400

Quantitative evaluation of skeletal muscle defects in second harmonic generation images  

PubMed Central

Abstract. Skeletal muscle pathologies cause irregularities in the normally periodic organization of the myofibrils. Objective grading of muscle morphology is necessary to assess muscle health, compare biopsies, and evaluate treatments and the evolution of disease. To facilitate such quantitation, we have developed a fast, sensitive, automatic imaging analysis software. It detects major and minor morphological changes by combining texture features and Fourier transform (FT) techniques. We apply this tool to second harmonic generation (SHG) images of muscle fibers which visualize the repeating myosin bands. Texture features are then calculated by using a Haralick gray-level cooccurrence matrix in MATLAB. Two scores are retrieved from the texture correlation plot by using FT and curve-fitting methods. The sensitivity of the technique was tested on SHG images of human adult and infant muscle biopsies and of mouse muscle samples. The scores are strongly correlated to muscle fiber condition. We named the software MARS (muscle assessment and rating scores). It is executed automatically and is highly sensitive even to subtle defects. We propose MARS as a powerful and unbiased tool to assess muscle health. PMID:23377006

Liu, Wenhua; Raben, Nina; Ralston, Evelyn

2013-01-01

401

Quality evaluation of snow lotus (Saussurea): quantitative chemical analysis and antioxidant activity assessment.  

PubMed

Snow lotus is commonly used as a medicinal plant and has great pharmacological value. To protect these endangered plants, in vitro propagation and cell cultures have been established in order to meet the growing market demand. The phenolic composition, antioxidant activities, total phenolic content (TPC) and total flavonoid content (TFC) from three most commonly used species, in vitro propagated lines and the cell cultures were investigated to qualify their pharmacological value. Quantitative analysis showed that the phenolics varied greatly among different species and the same species at different habitats. From this it can be inferred that the phenolics were influenced by genetic background and the environmental conditions. Significant correlations were observed between the antioxidant activity and several phenolics/TPC/TFC, suggesting that the phenolics are a major contributor of the antioxidant activity and are important for quality evaluation of snow lotus. Based on the abundance of phenolics, TPC, TFC and antioxidant activity, the order of the quality for wild species would be Saussurea involucrata > Saussurea medusa > Saussurea gossypiphora. For S. medusa, its quality judged by origin would be Shigatse > Lhasa > Nagqu. For in vitro propagated plants, the matured plants could be a reliable substitute for wild plants, and the dynamics of phenolics is critical for quality control of this monocarpic species. We provide the first report of quality comparison between the wild plants and the cell cultures. The advantages of developing cell cultures as alternatives for plants collected from the wild are discussed. PMID:20842365

Qiu, Jian; Xue, Xiaofeng; Chen, Fudong; Li, Chonghui; Bolat, Nuer; Wang, Xiaojun; Baima, Yuzhen; Zhao, Qiao; Zhao, Dexiu; Ma, Fengshan

2010-12-01

402

Quantitative evaluation of oxygenation in venous vessels using T2-Relaxation-Under-Spin-Tagging MRI.  

PubMed

Noninvasive measurement of cerebral venous oxygenation can serve as a tool for better understanding fMRI signals and for clinical evaluation of brain oxygen homeostasis. In this study a novel technique, T2-Relaxation-Under-Spin-Tagging (TRUST) MRI, is developed to estimate oxygenation in venous vessels. This method uses the spin labeling principle to automatically isolate pure blood signals from which T2 relaxation times are determined using flow-insensitive T2-preparation pulses. The blood T2 is then converted to blood oxygenation using a calibration plot. In vivo experiments gave a baseline venous oxygenation of 64.8 +/- 6.3% in sagittal sinus in healthy volunteers (n = 24). Reproducibility studies demonstrated that the standard deviation across trials was 2.0 +/- 1.1%. The effects of repetition time and inversion time selections were investigated. The TRUST technique was further tested using various physiologic challenges. Hypercapnia induced an increase in venous oxygenation by 13.8 +/- 1.1%. On the other hand, caffeine ingestion resulted in a decrease in oxygenation by 7.0 +/- 1.8%. Contrast agent infusion (Gd-DTPA, 0.1 mmol/kg) reduced venous blood T2 by 11.2 ms. The results of this study show that TRUST MRI is a useful technique for quantitative assessment of blood oxygenation in the brain. PMID:18666116

Lu, Hanzhang; Ge, Yulin

2008-08-01

403

Evaluation of reference genes for gene expression analysis using quantitative RT-PCR in Azospirillum brasilense.  

PubMed

Azospirillum brasilense is a nitrogen fixing bacterium that has been shown to have various beneficial effects on plant growth and yield. Under normal conditions A. brasilense exists in a motile flagellated form, which, under starvation or stress conditions, can undergo differentiation into an encapsulated, cyst-like form. Quantitative RT-PCR can be used to analyse changes in gene expression during this differentiation process. The accuracy of quantification of mRNA levels by qRT-PCR relies on the normalisation of data against stably expressed reference genes. No suitable set of reference genes has yet been described for A. brasilense. Here we evaluated the expression of ten candidate reference genes (16S rRNA, gapB, glyA, gyrA, proC, pykA, recA, recF, rpoD, and tpiA) in wild-type and mutant A. brasilense strains under different culture conditions, including conditions that induce differentiation. Analysis with the software programs BestKeeper, NormFinder and GeNorm indicated that gyrA, glyA and recA are the most stably expressed reference genes in A. brasilense. The results also suggested that the use of two reference genes (gyrA and glyA) is sufficient for effective normalisation of qRT-PCR data. PMID:24841066

McMillan, Mary; Pereg, Lily

2014-01-01

404

Evaluation of Large Scale Quantitative Proteomic Assay Development Using Peptide Affinity-based Mass Spectrometry*  

PubMed Central

Stable isotope standards and capture by antipeptide antibodies (SISCAPA) couples affinity enrichment of peptides with stable isotope dilution and detection by multiple reaction monitoring mass spectrometry to provide quantitative measurement of peptides as surrogates for their respective proteins. In this report, we describe a feasibility study to determine the success rate for production of suitable antibodies for SISCAPA assays in order to inform strategies for large-scale assay development. A workflow was designed that included a multiplex immunization strategy in which up to five proteotypic peptides from a single protein target were used to immunize individual rabbits. A total of 403 proteotypic tryptic peptides representing 89 protein targets were used as immunogens. Antipeptide antibody titers were measured by ELISA and 220 antipeptide antibodies representing 89 proteins were chosen for affinity purification. These antibodies were characterized with respect to their performance in SISCAPA-multiple reaction monitoring assays using trypsin-digested human plasma matrix. More than half of the assays generated were capable of detecting the target peptide at concentrations of less than 0.5 fmol/?l in human plasma, corresponding to protein concentrations of less than 100 ng/ml. The strategy of multiplexing five peptide immunogens was successful in generating a working assay for 100% of the targeted proteins in this evaluation study. These results indicate it is feasible for a single laboratory to develop hundreds of assays per year and allow planning for cost-effective generation of SISCAPA assays. PMID:21245105

Whiteaker, Jeffrey R.; Zhao, Lei; Abbatiello, Susan E.; Burgess, Michael; Kuhn, Eric; Lin, ChenWei; Pope, Matthew E.; Razavi, Morteza; Anderson, N. Leigh; Pearson, Terry W.; Carr, Steven A.; Paulovich, Amanda G.

2011-01-01

405

Quantitative evaluation of the requirements for the promotion as associate professor at German Medical Faculties  

PubMed Central

Background: First quantitative evaluation of the requirements for the promotion as associate professor (AP) at German Medical Faculties Material and methods: Analysis of the AP-regulations of German Medical Faculties according to a validated scoring system, which has been adapted to this study. Results: The overall scoring for the AP-requirements at 35 German Medical Faculties was 13.5±0.6 of 20 possible scoring points (95% confidence interval 12.2-14.7). More than 88% of the AP-regulations demand sufficient performance in teaching and research with adequate scientific publication. Furthermore, 83% of the faculties expect an expert review of the candidate´s performance. Conference presentations required as an assistant professor as well as the reduction of the minimum time as an assistant professor do only play minor roles. Conclusion: The requirements for assistant professors to get nominated as an associate professor at German Medical Faculties are high with an only small range. In detail, however, it can be seen that there still exists large heterogeneity, which hinders equal opportunities and career possibilities. These data might be used for the ongoing objective discussion. PMID:23255964

Sorg, Heiko; Knobloch, Karsten

2012-01-01

406

Bacterial decomposition of coral mucus as evaluated by long-term and quantitative observation  

NASA Astrophysics Data System (ADS)

Coral mucus released from Acropora formosa and Montipora digitata was incubated with bacteria under dark conditions for 1 year to evaluate the quantitative degradability. All the mucus samples showed a similar decomposition pattern: about 80% of total organic carbon (TOC) in the mucus was mineralized within 1 month, while some mucus was slowly decomposed over the 1 year. Regression analysis using an exponential curve considering three degradability pools (labile, semilabile, and refractory) fitted the changes of the TOC concentrations very well ( r 2 > 0.99). Compiling the data on the two coral species, the labile organic C in the coral mucus had mineralization rates of 10-18% d-1 and accounted for 79-87% of the initial TOC in the mucus. Semilabile organic C had mineralization rates of 0.3-1.6% d-1 and accounted for 11-18% of the initial TOC. Refractory organic C accounted for 6% at most. These results suggest that not all coral mucus is rapidly decomposed by bacteria but some mucus remains as semilabile and refractory organic matter for several months.

Tanaka, Y.; Ogawa, H.; Miyajima, T.

2011-06-01

407

Environmental determinants of tropical forest and savanna distribution: A quantitative model evaluation and its implication  

NASA Astrophysics Data System (ADS)

distributions of tropical ecosystems are rapidly being altered by climate change and anthropogenic activities. One possible trend—the loss of tropical forests and replacement by savannas—could result in significant shifts in ecosystem services and biodiversity loss. However, the influence and the relative importance of environmental factors in regulating the distribution of tropical forest and savanna biomes are still poorly understood, which makes it difficult to predict future tropical forest and savanna distributions in the context of climate change. Here we use boosted regression trees to quantitatively evaluate the importance of environmental predictors—mainly climatic, edaphic, and fire factors—for the tropical forest-savanna distribution at a mesoscale across the tropics (between 15°N and 35°S). Our results demonstrate that climate alone can explain most of the distribution of tropical forest and savanna at the scale considered; dry season average precipitation is the single most important determinant across tropical Asia-Australia, Africa, and South America. Given the strong tendency of increased seasonality and decreased dry season precipitation predicted by global climate models, we estimate that about 28% of what is now tropical forest would likely be lost to savanna by the late 21st century under the future scenario considered. This study highlights the importance of climate seasonality and interannual variability in predicting the distribution of tropical forest and savanna, supporting the climate as the primary driver in the savanna biogeography.

Zeng, Zhenzhong; Chen, Anping; Piao, Shilong; Rabin, Sam; Shen, Zehao

2014-07-01

408

Quantitative Evaluation of MODIS Fire Radiative Power Measurement for Global Smoke Emissions Assessment  

NASA Technical Reports Server (NTRS)

Satellite remote sensing is providing us tremendous opportunities to measure the fire radiative energy (FRE) release rate or power (FRP) from open biomass burning, which affects many vegetated regions of the world on a seasonal basis. Knowledge of the biomass burning characteristics and emission source strengths of different (particulate and gaseous) smoke constituents is one of the principal ingredients upon which the assessment, modeling, and forecasting of their distribution and impacts depend. This knowledge can be gained through accurate measurement of FRP, which has been shown to have a direct relationship with the rates of biomass consumption and emissions of major smoke constituents. Over the last decade or so, FRP has been routinely measured from space by both the MODIS sensors aboard the polar orbiting Terra and Aqua satellites, and the SEVIRI sensor aboard the Meteosat Second Generation (MSG) geostationary satellite. During the last few years, FRP has steadily gained increasing recognition as an important parameter for facilitating the development of various scientific studies and applications relating to the quantitative characterization of biomass burning and their emissions. To establish the scientific integrity of the FRP as a stable quantity that can be measured consistently across a variety of sensors and platforms, with the potential of being utilized to develop a unified long-term climate data record of fire activity and impacts, it needs to be thoroughly evaluated, calibrated, and validated. Therefore, we are conducting a detailed analysis of the FRP products from MODIS to evaluate the uncertainties associated with them, such as those due to the effects of satellite variable observation geometry and other factors, in order to establish their error budget for use in diverse scientific research and applications. In this presentation, we will show recent results of the MODIS FRP uncertainty analysis and error mitigation solutions, and demonstrate their implications for biomass burning emissions assessment.

Ichoku, Charles; Ellison, Luke

2011-01-01

409

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

SciTech Connect

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

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

2009-04-15

410

Neural network approach to holographic nondestructive testing.  

PubMed

A neural network approach for the automatic detection of defects by evaluation of holographic interference patterns of the loaded technical components is described. Translation- as well as rotation-invariant features are defined based on the maximal local slope of the intensity and a partition of the interference pattern into nonoverlapping areas. The training sample set is generated by computer simulation of interferograms directed by a few typical experimentally measured samples. Practical results show the feasibility of the method. A strategy for application of neural networks to any holographic nondestructive testing task is outlined. PMID:21037676

Kreis, T; Jüptner, W; Biedermann, R

1995-03-10

411

Is the Strategic Role of Large-Scale Information Systems an Essential Part of Quantitative Evaluation Process?  

Microsoft Academic Search

The purpose of this paper is trying to gain a better understanding of the role of strategies in the quantitative evaluation process of large-scale information systems and in the alignment between system effectiveness and operational effectiveness. Also, we explores the contribution of strategies to the improvement of operational performance after the implementation of large-scale systems. We uses the results of

Ricardo Santa; W. K. Daniel Pun

2010-01-01

412

Quantitative Analysis of Verbal Expressions in Comments from Evaluation Committee Reviewers in AIST between Fiscal Years 2001 and 2008  

ERIC Educational Resources Information Center

This article discusses the quantitative analysis of verbal expressions of comments from the evaluation committee reviewers for 8 years (FY2001-FY2008) at the Japanese Public Research Institute, National Institute of Advanced Industrial Science and Technology (AIST). First, the terms often appearing in the comment sheets were observed. Moreover,…

Yamamoto, Tetsuya

2010-01-01

413

Quantitative Evaluation of Carotid Plaque Echogenicity by Integrated Backscatter Analysis: Correlation with Symptomatic History and Histologic Findings  

Microsoft Academic Search

Background and Purpose: Echogenicity of carotid plaque well reflects the risk of ischemic stroke and may be predictive of the histologic content of the plaque. However, objective evaluation of plaque echogenicity has been hampered by a lack of established quantitative measures. This study examined the relation between echogenicity assessed by integrated backscatter (IBS) analysis and (1) symptomatic history and (2)

Keiko Nagano; Hiroshi Yamagami; Yoshitane Tsukamoto; Kazuyuki Nagatsuka; Masahiro Yasaka; Izumi Nagata; Masatsugu Hori; Kazuo Kitagawa; Hiroaki Naritomi

2008-01-01

414

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

E-print Network

EnviLOD WP5: Quantitative Evaluation of LOD-based Semantic Enrichment on Environmental Science approach for LOD-based semantic enrichment of metadata and full-text scientific articles. Secondly- brary information discovery tool and tentative benefits of LOD-based semantic enrichment are identified

Maynard, Diana

415

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

Microsoft Academic Search

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

Conor P. McGowan; Mark R. Ryan

2009-01-01

416

Use of Neutron Activation and X-Ray Fluorescence with Radioactive Sources (Cf-252 and Am-241) for the Instrumental Quali-Quantitative Simultaneous Analysis of Some Elements in Samples of Mineral Supplement for Animals.  

National Technical Information Service (NTIS)

To study the possibility of using two non-destructive (neutron activation and X-ray fluorescence) analyses in simultaneous quali-quantitative evaluations of some elements in mineral supplements for animals, a Cf-252 neutron source (11.3 mCi; 21.1 mu grams...

S. M. Simabuco

1984-01-01

417

Evaluation of early visual recovery in pituitary macroadenomas after endoscopic endonasal transphenoidal surgery: Quantitative assessment with diffusion tensor imaging (DTI)  

Microsoft Academic Search

Background  Visual field analyses reflect the degree of the compression to the optic nerve that results the structural damage of the nerve.\\u000a These structural damages can be evaluated by diffusion tensor imaging (DTI), which assesses the structural integrity of white\\u000a matter tracts. Thus, we evaluated the quantitative assessment of early visual recovery in patients with pituitary macroadenomas,\\u000a corresponding DTI with visual

Ihsan Anik; Yonca Anik; Kenan Koc; Savas Ceylan; Hamza Genc; Ozgul Altintas; Dilek Ozdamar; Duygu Baykal Ceylan

2011-01-01

418

The quantitative evaluation of the Clinical and Translational Science Awards (CTSA) program based on science mapping and scientometric analysis.  

PubMed

The Clinical and Translational Science Awards (CTSA) program is one of the most important initiatives in translational medical funding. The quantitative evaluation of the efficiency and performance of the CTSA program has a significant referential meaning for the decision making of global translational medical funding. Using science mapping and scientometric analytic tools, this study quantitatively analyzed the scientific articles funded by the CTSA program. The results of the study showed that the quantitative productivities of the CTSA program had a stable increase since 2008. In addition, the emerging trends of the research funded by the CTSA program covered clinical and basic medical research fields. The academic benefits from the CTSA program were assisting its members to build a robust academic home for the Clinical and Translational Science and to attract other financial support. This study provided a quantitative evaluation of the CTSA program based on science mapping and scientometric analysis. Further research is required to compare and optimize other quantitative methods and to integrate various research results. PMID:24330689

Zhang, Yin; Wang, Lei; Diao, Tianxi

2013-12-01

419

Nondestructive characterization of the elastic constants of fiber reinforced composites  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01