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Sample records for examination nde reliability

  1. Nondestructive examination (NDE) reliability for inservice inspection of light waters reactors

    SciTech Connect

    Doctor, S.R.; Deffenbaugh, J.D.; Good, M.S.; Green, E.R.; Heasler, P.G.; Simonen, F.A.; Spanner, J.C.; Taylor, T.T. )

    1989-11-01

    Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactors (NDE Reliability) Program at the Pacific Northwest Laboratory was established by the Nuclear Regulatory Commission to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWRs); using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvements that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to ASME Code and Regulatory requirements, based on material properties, service conditions, and NDE uncertainties. The program scope is limited to ISI of the primary systems including the piping, vessel, and other inspected components. This is a progress report covering the programmatic work from April 1988 through September 1988. 33 refs., 70 figs., 12 tabs.

  2. Nondestructive Examination (NDE) Reliability for Inservice Inspection of Light Water Reactors. Semiannual report, October 1990--March 1991: Volume 13

    SciTech Connect

    Doctor, S.R.; Good, M.S.; Heasler, P.G.; Hockey, R.L.; Simonen, F.A.; Spanner, J.C.; Taylor, T.T.; Vo, T.V.

    1992-07-01

    The Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactors (NDE Reliability) Program at the Pacific Northwest Laboratory was established by the Nuclear Regulatory Commission to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWRs); using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvements that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to the Regulatory and ASME Code requirements, based on material properties, service conditions, and NDE uncertainties.

  3. Assessment of NDE Reliability Data

    NASA Technical Reports Server (NTRS)

    Yee, B. G. W.; Chang, F. H.; Covchman, J. C.; Lemon, G. H.; Packman, P. F.

    1976-01-01

    Twenty sets of relevant Nondestructive Evaluation (NDE) reliability data have been identified, collected, compiled, and categorized. A criterion for the selection of data for statistical analysis considerations has been formulated. A model to grade the quality and validity of the data sets has been developed. Data input formats, which record the pertinent parameters of the defect/specimen and inspection procedures, have been formulated for each NDE method. A comprehensive computer program has been written to calculate the probability of flaw detection at several confidence levels by the binomial distribution. This program also selects the desired data sets for pooling and tests the statistical pooling criteria before calculating the composite detection reliability. Probability of detection curves at 95 and 50 percent confidence levels have been plotted for individual sets of relevant data as well as for several sets of merged data with common sets of NDE parameters.

  4. Nondestructive Examination (NDE) Reliability for Inservice Inspection of Light Water Reactors. Volume 15, Semiannual report: October 1991--March 1992

    SciTech Connect

    Doctor, S.R.; Diaz, A.A.; Friley, J.R.

    1993-09-01

    The Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactors (NDE Reliability) Program at the Pacific Northwest Laboratory was established by the Nuclear Regulatory Commission to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWRs); using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvements that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to ASME Code and Regulatory requirements, based on material properties, service conditions, and NDE uncertainties. The program scope is limited to ISI of the primary systems including the piping, vessel, and other components inspected in accordance with Section XI of the ASME Code. This is a progress report covering the programmatic work from October 1991 through March 1992.

  5. Nondestructive Examination (NDE) Reliability for Inservice Inspection of Light Water Reactors. Semiannual report, April 1992--September 1992: Volume 16

    SciTech Connect

    Doctor, S.R.; Diaz, A.A.; Friley, J.R.; Greenwood, M.S.; Heasler, P.G.; Kurtz, R.J.; Simonen, F.A.; Spanner, J.C.; Vo, T.V.

    1993-11-01

    The Evaluation and Improvement of NDE Reliability for Inservice inspection of Light Water Reactors (NDE Reliability) Program at the Pacific Northwest Laboratory was established by the Nuclear Regulatory Commission to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWRs);using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvements that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to the Regulatory and ASME Code requirements, based on material properties, service conditions, and NDE uncertainties. The program scope is limited to ISI of the primary systems including the piping, vessel and other components inspected in accordance with Section XI of the ASME Code. This is a programs report covering the programmatic work from April 1992 through September 1992.

  6. Nondestructive Examination (NDE) Reliability for Inservice Inspection of Light Water Reactors. Volume 14, Semiannual report, April 1991--September 1991

    SciTech Connect

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

    1992-07-01

    The Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactors (NDE Reliability) Program at the Pacific Northwest Laboratory was established by the Nuclear Regulatory Commission to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWR`s); using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvements that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to the Regulatory and ASME Code requirements, based on material properties, service conditions, and NDE uncertainties. The program scope is limited to ISI of the primary systems including the piping, vessel, and other components inspected in accordance with Section XI of the ASME Code. This is a progress report covering the programmatic work from April 1991 through September 1991.

  7. Assessment of NDE reliability data

    NASA Technical Reports Server (NTRS)

    Yee, B. G. W.; Couchman, J. C.; Chang, F. H.; Packman, D. F.

    1975-01-01

    Twenty sets of relevant nondestructive test (NDT) reliability data were identified, collected, compiled, and categorized. A criterion for the selection of data for statistical analysis considerations was formulated, and a model to grade the quality and validity of the data sets was developed. Data input formats, which record the pertinent parameters of the defect/specimen and inspection procedures, were formulated for each NDE method. A comprehensive computer program was written and debugged to calculate the probability of flaw detection at several confidence limits by the binomial distribution. This program also selects the desired data sets for pooling and tests the statistical pooling criteria before calculating the composite detection reliability. An example of the calculated reliability of crack detection in bolt holes by an automatic eddy current method is presented.

  8. Statistical Tests of Reliability of NDE

    NASA Technical Reports Server (NTRS)

    Baaklini, George Y.; Klima, Stanley J.; Roth, Don J.; Kiser, James D.

    1987-01-01

    Capabilities of advanced material-testing techniques analyzed. Collection of four reports illustrates statistical method for characterizing flaw-detecting capabilities of sophisticated nondestructive evaluation (NDE). Method used to determine reliability of several state-of-the-art NDE techniques for detecting failure-causing flaws in advanced ceramic materials considered for use in automobiles, airplanes, and space vehicles.

  9. NDE (nondestructive examination) development for ceramics for advanced heat engines

    SciTech Connect

    McClung, R.W. , Powell, TN ); Johnson, D.R. )

    1991-01-01

    The Department of Energy (DOE) Ceramic Technology for Advanced Heat Engines (CTAHE) project was initiated in 1983 to meet the ceramic technology needs of DOE's advanced heat engines programs (i.e., advanced gas turbines and low heat rejection diesels). The objective is to establish an industrial ceramic technology base for reliable and cost-effective high-temperature components. Reliability of ceramics was recognized as the major technology need. To increase the material reliability of current and new ceramics, advances were needed in component design methodology, materials processing technology, and data base/life prediction. Nondestructive examination (NDE) was identified as one of the key elements in the approach to high-reliability components. An assessment was made of the current status of NDE for structural ceramics, and a report was prepared containing the results and recommendations for needed development. Based on these recommendations, a long-range NDE development program has been established in the CTAHE project to address these needs.

  10. Impact of NDE reliability developments on risk-informed methods

    SciTech Connect

    Walker, S.M.; Ammirato, F.V.

    1996-12-01

    Risk informed inspection procedures are being developed to more effectively and economically manage degradation in plant piping systems. A key element of this process is applying nondestructive examination (NDE) procedures capable of detecting specific damage mechanisms that may be operative in particular locations. Thus, the needs of risk informed analysis are closely coupled with a firm understanding of the capability of NDE.

  11. Conclusions of the 6th European American Workshop on reliability of NDE

    NASA Astrophysics Data System (ADS)

    Mueller, Christina; Bertovic, Marija; Kanzler, Daniel; Ronneteg, Ulf

    2016-02-01

    The principles of Open Space Technology (OST) were again applied to discuss burning issues in the field of NDE reliability. The results of the discussions among NDE professionals concerning new reliability methods, human factors and integrated solutions will be presented.

  12. Integration of NDE Reliability and Fracture Mechanics

    SciTech Connect

    Becker, F. L.; Doctor, S. R.; Heas!er, P. G.; Morris, C. J.; Pitman, S. G.; Selby, G. P.; Simonen, F. A.

    1981-03-01

    The Pacific Northwest Laboratory is conducting a four-phase program for measuring and evaluating the effectiveness and reliability of in-service inspection (lSI} performed on the primary system piping welds of commercial light water reactors (LWRs). Phase I of the program is complete. A survey was made of the state of practice for ultrasonic rsr of LWR primary system piping welds. Fracture mechanics calculations were made to establish required nondestrutive testing sensitivities. In general, it was found that fatigue flaws less than 25% of wall thickness would not grow to failure within an inspection interval of 10 years. However, in some cases failure could occur considerably faster. Statistical methods for predicting and measuring the effectiveness and reliability of lSI were developed and will be applied in the "Round Robin Inspections" of Phase II. Methods were also developed for the production of flaws typical of those found in service. Samples fabricated by these methods wilI be used in Phase II to test inspection effectiveness and reliability. Measurements were made of the influence of flaw characteristics {i.e., roughness, tightness, and orientation) on inspection reliability. These measurernents, as well as the predictions of a statistical model for inspection reliability, indicate that current reporting and recording sensitivities are inadequate.

  13. Uncertainties in NDE Reliability and Assessing the Impact on RI-ISI

    SciTech Connect

    Doctor, Steven R.; Anderson, Michael T.

    2010-08-01

    A major thrust in the past 20 years has been to upgrade nondestructive examinations (NDE) for use in inservice inspection (ISI) programs to more effectively manage degradation at operating nuclear power plants. Risk-informed ISI (RI-ISI) is one of the outcomes of this work, and this approach relies heavily on the reliability of NDE, when properly applied, to detect sources of expected degradation. There have been a number of improvements in the reliability of NDE, specifically in ultrasonic testing (UT), through training of examiners, and improved equipment and procedure development. However, the most significant improvements in UT were derived by moving from prescriptive requirements to performance based requirements. Even with these substantial improvements, NDE contains significant uncertainties and RI-ISI programs need to address and accommodate this factor. As part of the work that PNNL is conducting for the U. S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research, we are examining the impact of these uncertainties on the effectiveness of RI-ISI programs.

  14. NDE for utilities: maintaining reliability in a competitive environment

    NASA Astrophysics Data System (ADS)

    Tilley, Richard M.; Brett, Colin R.

    1996-11-01

    US utilities are facing an increasingly deregulated market place in which price competition will be featured. Correspondingly, utilities are aggressively pursuing cost reduction efforts in all phases of electric power production. Power plant operating and maintenance cost reduction efforts must be carefully managed, however, to avoid a potential reduction in operating reliability. To succeed in this effort will require new NDE techniques and decision support tools. Key attributes of such new techniques will be improved measurement speed and accuracy, reduced preparation requirements, automated data acquisition, and computer-based analysis support. Tools will be required to assist power plant personnel in making the best decisions on what, when, and how to inspect plant components to achieve overall economic objectives.

  15. NDE reliability and probability of detection (POD) evolution and paradigm shift

    SciTech Connect

    Singh, Surendra

    2014-02-18

    The subject of NDE Reliability and POD has gone through multiple phases since its humble beginning in the late 1960s. This was followed by several programs including the important one nicknamed “Have Cracks – Will Travel” or in short “Have Cracks” by Lockheed Georgia Company for US Air Force during 1974–1978. This and other studies ultimately led to a series of developments in the field of reliability and POD starting from the introduction of fracture mechanics and Damaged Tolerant Design (DTD) to statistical framework by Bernes and Hovey in 1981 for POD estimation to MIL-STD HDBK 1823 (1999) and 1823A (2009). During the last decade, various groups and researchers have further studied the reliability and POD using Model Assisted POD (MAPOD), Simulation Assisted POD (SAPOD), and applying Bayesian Statistics. All and each of these developments had one objective, i.e., improving accuracy of life prediction in components that to a large extent depends on the reliability and capability of NDE methods. Therefore, it is essential to have a reliable detection and sizing of large flaws in components. Currently, POD is used for studying reliability and capability of NDE methods, though POD data offers no absolute truth regarding NDE reliability, i.e., system capability, effects of flaw morphology, and quantifying the human factors. Furthermore, reliability and POD have been reported alike in meaning but POD is not NDE reliability. POD is a subset of the reliability that consists of six phases: 1) samples selection using DOE, 2) NDE equipment setup and calibration, 3) System Measurement Evaluation (SME) including Gage Repeatability and Reproducibility (Gage R and R) and Analysis Of Variance (ANOVA), 4) NDE system capability and electronic and physical saturation, 5) acquiring and fitting data to a model, and data analysis, and 6) POD estimation. This paper provides an overview of all major POD milestones for the last several decades and discuss rationale for using

  16. NDE reliability and probability of detection (POD) evolution and paradigm shift

    NASA Astrophysics Data System (ADS)

    Singh, Surendra

    2014-02-01

    The subject of NDE Reliability and POD has gone through multiple phases since its humble beginning in the late 1960s. This was followed by several programs including the important one nicknamed "Have Cracks - Will Travel" or in short "Have Cracks" by Lockheed Georgia Company for US Air Force during 1974-1978. This and other studies ultimately led to a series of developments in the field of reliability and POD starting from the introduction of fracture mechanics and Damaged Tolerant Design (DTD) to statistical framework by Bernes and Hovey in 1981 for POD estimation to MIL-STD HDBK 1823 (1999) and 1823A (2009). During the last decade, various groups and researchers have further studied the reliability and POD using Model Assisted POD (MAPOD), Simulation Assisted POD (SAPOD), and applying Bayesian Statistics. All and each of these developments had one objective, i.e., improving accuracy of life prediction in components that to a large extent depends on the reliability and capability of NDE methods. Therefore, it is essential to have a reliable detection and sizing of large flaws in components. Currently, POD is used for studying reliability and capability of NDE methods, though POD data offers no absolute truth regarding NDE reliability, i.e., system capability, effects of flaw morphology, and quantifying the human factors. Furthermore, reliability and POD have been reported alike in meaning but POD is not NDE reliability. POD is a subset of the reliability that consists of six phases: 1) samples selection using DOE, 2) NDE equipment setup and calibration, 3) System Measurement Evaluation (SME) including Gage Repeatability &Reproducibility (Gage R&R) and Analysis Of Variance (ANOVA), 4) NDE system capability and electronic and physical saturation, 5) acquiring and fitting data to a model, and data analysis, and 6) POD estimation. This paper provides an overview of all major POD milestones for the last several decades and discuss rationale for using Integrated

  17. NDE reliability and process control for structural ceramics

    NASA Technical Reports Server (NTRS)

    Baaklini, G. Y.

    1987-01-01

    The reliability of microfocus X-radiography and scanning laser acoustic microscopy for detecting microvoids in silicon nitride and silicon carbide was statistically evaluated. Materials- and process-related parameters that influenced the statistical findings in research samples are discussed. The use of conventional X-radiography in controlling and optimizing the processing and sintering of an Si3N4-SiO2-Y2O3 composition designated NASA 6Y is described. Radiographic evaluation and guidance helped develop uniform high-density Si3N4 modulus-of-rupture bars with improved four-point flexural strength (857, 544, and 462 MPa at room temperature, 1200 C, and 1370 C, respectively) and reduced strength scatter.

  18. NDE reliability and process control for structural ceramics

    NASA Technical Reports Server (NTRS)

    Baaklini, G. Y.

    1986-01-01

    The reliability of microfocus x-radiography and scanning laser acoustic microscopy for detecting microvoids in silicon nitride and silicon carbide was statistically evaluated. Materials- and process-related parameters that influenced the statistical findings in research samples are discussed. The use of conventional x-radiography in controlling and optimizing the processing and sintering of an Si3N4-Si02-Y203 composition designated NASA 6Y is described. Radiographic evaluation and guidance helped develop uniform high-density Si3N4 modulus-of-rupture bars with improved four-point flexural strength (857, 544, and 462 MPa at room temperature, 1200 C, and 1370 C, respectively) and reduced strength scatter.

  19. Nuclear Technology. Course 26: Nondestructive Examination (NDE) Techniques I. Module 26-6, Radiography Inspection.

    ERIC Educational Resources Information Center

    Pelton, Rick; Espy, John

    This sixth in a series of seven modules for a course titled Nondestructive Examination (NDE) Techniques I explains radiographic inspection as a means of nondestructively examining components, assemblies, structures, and fabricated piping. The module follows a typical format that includes the following sections: (1) introduction, (2) module…

  20. Nondestructive Examination (NDE) Detection and Characterization of Degradation Precursors, Technical Progress Report for FY 2012

    SciTech Connect

    Ramuhalli, P.; Meyer, R.M.; Fricke, J.M.; Prowant, M.S.; Coble, J.B.; Griffin, J.W.; Pitman, S.G.; Dahl, M.E.; Kafentzis, T.A.; Roosendaal, T.J.

    2012-09-01

    The overall objective of this project was to investigate the effectiveness of nondestructive examination (NDE) technology in detecting material degradation precursors by initiating and growing cracks in selected materials and using NDE methods to measure crack precursors prior to the onset of cracking. Nuclear reactor components are subject to stresses over time that are not precisely known and that make the life expectancy of components difficult to determine. To prevent future issues with the operation of these plants because of unforeseen failure of components, NDE technology is needed that can be used to identify and quantify precursors to macroscopic degradation of materials. Some of the NDE methods being researched as possible solutions to the precursor detection problem are magnetic Barkhausen noise, nonlinear ultrasonics, acoustic emission, eddy current measurements, and guided wave technology. In FY12, the objective was to complete preliminary assessment of advanced NDE techniques for sensitivity to degradation precursors, using prototypical degradation mechanisms in laboratory-scale measurements. This present document reports on the deliverable that meets the following milestone: M3LW-12OR0402143 – Report detailing an initial demonstration on samples from the crack-initiation tests will be provided (demonstrating acceleration of the work).

  1. Nuclear Technology. Course 26: Nondestructive Examination (NDE) Techniques I. Module 26-2, Leak Tests.

    ERIC Educational Resources Information Center

    Groseclose, Richard

    This second in a series of seven modules for a course titled Nondestructive Examination (NDE) Techniques I describes the predominantly used leak test methods in nuclear power plants. More specifically, the module describes these test methods, the testing techniques, and the associated quality assurance requirements. The module follows a typical…

  2. Nuclear Technology. Course 26: Nondestructive Examination (NDE) Techniques I. Module 26-5, Fundamentals of Radiography.

    ERIC Educational Resources Information Center

    Groseclose, Richard

    This fifth in a series of seven modules for a course titled Nondestructive Examination (NDE) Techniques I explains the radiographic process, from radiation source selection to equipment and specimen selection and arrangement, and film processing. The module follows a typical format that includes the following sections: (1) introduction, (2) module…

  3. Nuclear Technology. Course 26: Nondestructive Examination (NDE) Techniques I. Module 26-3, Hydrostatic Tests.

    ERIC Educational Resources Information Center

    Pelton, Rick; Espy, John

    This third in a series of seven modules for a course titled Nondestructive Examination (NDE) Techniques I describes the principles and practices associated with hydrostatic testing. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3) objectives, (4) notes to instructor/student,…

  4. Probabilistic model for pressure vessel reliability incorporating fracture mechanics and nondestructive examination

    SciTech Connect

    Tow, D.M.; Reuter, W.G.

    1998-03-01

    A probabilistic model has been developed for predicting the reliability of structures based on fracture mechanics and the results of nondestructive examination (NDE). The distinctive feature of this model is the way in which inspection results and the probability of detection (POD) curve are used to calculate a probability density function (PDF) for the number of flaws and the distribution of those flaws among the various size ranges. In combination with a probabilistic fracture mechanics model, this density function is used to estimate the probability of failure (POF) of a structure in which flaws have been detected by NDE. The model is useful for parametric studies of inspection techniques and material characteristics.

  5. NDE research efforts at the FAA Center for Aviation Systems Reliability

    NASA Technical Reports Server (NTRS)

    Thompson, Donald O.; Brasche, Lisa J. H.

    1992-01-01

    The Federal Aviation Administration-Center for Aviation Systems Reliability (FAA-CASR), a part of the Institute for Physical Research and Technology at Iowa State University, began operation in the Fall of 1990 with funding from the FAA. The mission of the FAA-CASR is to develop quantitative nondestructive evaluation (NDE) methods for aircraft structures and materials including prototype instrumentation, software, techniques, and procedures and to develop and maintain comprehensive education and training programs in aviation specific inspection procedures and practices. To accomplish this mission, FAA-CASR brings together resources from universities, government, and industry to develop a comprehensive approach to problems specific to the aviation industry. The problem areas are targeted by the FAA, aviation manufacturers, the airline industry and other members of the aviation business community. This consortium approach ensures that the focus of the efforts is on relevant problems and also facilitates effective transfer of the results to industry.

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

    SciTech Connect

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

    1991-10-01

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

  7. An International Round-Robin Test of NDE Reliability for PWSCC

    SciTech Connect

    Schuster, George J.; Cumblidge, Stephen E.; Doctor, Steven R.; Moyer, Carol E.

    2007-12-01

    In this paper we describe the round robin tests that have been designed and are being conducted in the international program. Participants in the PINC have offered more than 30 test blocks for use in round-robin tests of NDE effectiveness. The test blocks have more than 130 flaws in nickel-base weld metal that are intended to simulate PWSCC in a variety of component geometries. NDE techniques representative of current in-service inspections are being applied, along with emerging NDE approaches.

  8. Nuclear Technology. Course 32: Nondestructive Examination (NDE) Techniques II. Module 32-6, Operation of Eddy Current Test Equipment.

    ERIC Educational Resources Information Center

    Espy, John; Selleck, Ben

    This sixth in a series of six modules for a course titled Nondestructive Examination (NDE) Techniques II details eddy current examination of steam generator tubing. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3) objectives, (4) notes to instructor/student, (5) subject…

  9. Nuclear Technology. Course 32: Nondestructive Examination (NDE) Techniques II. Module 32-2, Operation of Ultrasonic Test Equipment.

    ERIC Educational Resources Information Center

    Espy, John

    This second in a series of six modules for a course titled Nondestructive Examination (NDE) II describes specific ultrasonic test techniques and calibration principles. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3) objectives, (4) notes to instructor/student, (5) subject…

  10. Nuclear Technology. Course 32: Nondestructive Examination (NDE) Techniques II. Module 32-1, Fundamentals of Ultrasonic Testing.

    ERIC Educational Resources Information Center

    Spaulding, Bruce

    This first in a series of six modules for a course titled Nondestructive Examination (NDE) Techniques II introduces the student/trainee to the basic behavior of ultrasound, describes ultrasonic test equipment, and outlines the principal methods of ultrasonic testing. The module follows a typical format that includes the following sections: (1)…

  11. Nuclear Technology. Course 26: Nondestructive Examination (NDE) Techniques I. Module 26-7, Radiographic Specifications and Code Requirements.

    ERIC Educational Resources Information Center

    Pelton, Rick; Espy, John

    This seventh in a series of seven modules for a course titled Nondestructive Examination (NDE) Techniques I describes radiographic specifications and code requirements. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3) objectives, (4) notes to instructor/student, (5) subject…

  12. Nuclear Technology. Course 32: Nondestructive Examination (NDE) II. Module 32-3, Fundamentals of Magnetic Particle Testing.

    ERIC Educational Resources Information Center

    Groseclose, Richard

    This third in a series of six modules for a course titled Nondestructive Examination (NDE) Techniques II explains the principles of magnets and magnetic fields and how they are applied in magnetic particle testing, describes the theory and methods of magnetizing test specimens, describes the test equipment used, discusses the principles and…

  13. Nuclear Technology. Course 32: Nondestructive Examination (NDE) Techniques II. Module 32-5, Fundamentals of Eddy Current Testing.

    ERIC Educational Resources Information Center

    Espy, John

    This fifth in a series of six modules for a course titled Nondestructive Examination (NDE) Techniques II describes the fundamental concepts applicable to eddy current testing in general. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3) objectives, (4) notes to…

  14. NDE detectability of fatigue-type cracks in high-strength alloys: NDI reliability assessments

    NASA Technical Reports Server (NTRS)

    Christner, Brent K.; Long, Donald L.; Rummel, Ward D.

    1988-01-01

    This program was conducted to generate quantitative flaw detection capability data for the nondestructive evaluation (NDE) techniques typically practiced by aerospace contractors. Inconel 718 and Haynes 188 alloy test specimens containing fatigue flaws with a wide distribution of sizes were used to assess the flaw detection capabilities at a number of contractor and government facilities. During this program 85 inspection sequences were completed presenting a total of 20,994 fatigue cracks to 53 different inspectors. The inspection sequences completed included 78 liquid penetrant, 4 eddy current, and 3 ultrasonic evaluations. The results of the assessment inspections are presented and discussed. In generating the flaw detection capability data base, procedures for data collection, data analysis, and specimen care and maintenance were developed, demonstrated, and validated. The data collection procedures and methods that evolved during this program for the measurement of flaw detection capabilities and the effects of inspection variables on performance are discussed. The Inconel 718 and Haynes 188 test specimens that were used in conducting this program and the NDE assessment procedures that were demonstrated, provide NASA with the capability to accurately assess the flaw detection capabilities of specific inspection procedures being applied or proposed for use on current and future fracture control hardware program.

  15. ORCHID - a computer simulation of the reliability of an NDE inspection system

    SciTech Connect

    Moles, M.D.C.

    1987-03-01

    CANDU pressurized heavy water reactors contain several hundred horizontally-mounted zirconium alloy pressure tubes. Following a pressure tube failure, a pressure tube inspection system called CIGARette was rapidly designed, manufactured and put in operation. Defects called hydride blisters were found to be the cause of the failure, and were detected using a combination of eddy current and ultrasonic scans. A number of improvements were made to CIGARette during the inspection period. The ORCHID computer program models the operation of the delivery system, eddy current and ultrasonic systems by imitating the on-reactor decision-making procedure. ORCHID predicts that during the early stage of development, less than one blistered tube in three would be detected, while less than one in two would be detected in the middle development stage. However, ORCHID predicts that during the late development stage, probability of detection will be over 90%, primarily due to the inclusion of axial ultrasonic scans (a procedural modification). Rotational and axial slip could severely reduce probability of detection. Comparison of CIGARette's inspection data with ORCHID's predictions indicate that the latter are compatible with the actual inspection results, through the numbers are small and data uncertain. It should be emphasized that the CIGARette system has been essentially replaced with the much more reliable CIGAR system.

  16. Examination of Single- and Multi-Channel GPR Bridge Deck Condition Assessment Methods with Comparison to Complementary NDE Results

    NASA Astrophysics Data System (ADS)

    Romero, Francisco A.; Manacorda, Guido; Simi, Alessandro; Gucunski, Nenad; Parvardeh, Hooman

    2013-04-01

    other NDE technologies. Not only did all the single- and multi-channel system comparisons generate nearly identical deterioration maps when GPR results were compared and examined, but mapped results obtained from other NDE methods on the same deck were used to identify zones where corrosive environment (electrical resistivity - ER) elastic modulus (ultrasonic surface wave - USW), and identified delaminations (impact-echo - IE) had commonality with the GPR results. A summary of the equipment used, as well as general data collection and analysis procedures is provided for the GPR condition assessments. Brief descriptions of background and references to how the complementary NDT technologies are deployed, and how data are interpreted, are also discussed. Comparative maps for all technologies are used for illustrative purposes.

  17. Reliability and Validity of the Pilot National Board Dental Examination.

    ERIC Educational Resources Information Center

    Kramer, Gene A.; DeMarais, David R.

    1992-01-01

    This study found that the restructured National Board Dental Examination Part II is a reliable test assessing a full range of cognitive behaviors, and a unidimensional test of comprehensive general dentistry, suggesting better testing of knowledge and problem-solving skills than on the traditional examination. Performance on the pilot and…

  18. Examining the reliability of ADAS-Cog change scores.

    PubMed

    Grochowalski, Joseph H; Liu, Ying; Siedlecki, Karen L

    2016-09-01

    The purpose of this study was to estimate and examine ways to improve the reliability of change scores on the Alzheimer's Disease Assessment Scale, Cognitive Subtest (ADAS-Cog). The sample, provided by the Alzheimer's Disease Neuroimaging Initiative, included individuals with Alzheimer's disease (AD) (n = 153) and individuals with mild cognitive impairment (MCI) (n = 352). All participants were administered the ADAS-Cog at baseline and 1 year, and change scores were calculated as the difference in scores over the 1-year period. Three types of change score reliabilities were estimated using multivariate generalizability. Two methods to increase change score reliability were evaluated: reweighting the subtests of the scale and adding more subtests. Reliability of ADAS-Cog change scores over 1 year was low for both the AD sample (ranging from .53 to .64) and the MCI sample (.39 to .61). Reweighting the change scores from the AD sample improved reliability (.68 to .76), but lengthening provided no useful improvement for either sample. The MCI change scores had low reliability, even with reweighting and adding additional subtests. The ADAS-Cog scores had low reliability for measuring change. Researchers using the ADAS-Cog should estimate and report reliability for their use of the change scores. The ADAS-Cog change scores are not recommended for assessment of meaningful clinical change. PMID:26708116

  19. Are Specialist Certification Examinations a Reliable Measure of Physician Competence?

    ERIC Educational Resources Information Center

    Burch, V. C.; Norman, G. R.; Schmidt, H. G.; van der Vleuten, C. P. M.

    2008-01-01

    High stakes postgraduate specialist certification examinations have considerable implications for the future careers of examinees. Medical colleges and professional boards have a social and professional responsibility to ensure their fitness for purpose. To date there is a paucity of published data about the reliability of specialist certification…

  20. Inter-Examiner Reliability in Meibomian Gland Dysfunction Assessment

    PubMed Central

    Powell, Daniel R.; Nichols, Jason J.; Nichols, Kelly K

    2012-01-01

    Purpose. We evaluated inter-examiner reliability in grading of clinical variables associated with meibomian gland dysfunction (MGD) in real-time examination versus a graded digital image. Methods. Meibography grading of meibomian gland atrophy and acini appearance, and slit-lamp grading of lid debris and telangiectasias were conducted on 410 post-menopausal women. Meibography and slit-lamp photos were captured digitally and saved for analysis by a masked examiner. Gland atrophy was graded as a proportion of partial glands in the lower lid, and acini appearance by the presence/absence of grape-like clusters. Lid debris and telangiectasias were graded based on severity and quantity from the same image, respectively. Observed agreement and weighted kappas (κw) with 95% confidence intervals (CI) determined the degree of inter-examiner reliability between grading of these clinical variables in real-time examination and digital photographs using a multiple-point categorical scale. Results. Observed agreement was determined for telangiectasias (40.6%), lid debris (50.9%), gland dropout (42.8%), and acini appearance (54.5%). Inter-examiner reliability for the four clinical outcomes ranged from fair agreement for acini appearance (κw = 0.23, 95% CI = 0.14–0.32) and lid debris (κw = 0.24, 0.16–0.32) to moderate agreement for gland dropout (κw = 0.50, 0.40–0.59) and telangiectasias (κw = 0.47, 0.39–0.55). Conclusions. Gland dropout and potentially lid telangiectasia grading from a photograph are more representative of grading in a real-time examination compared to acini appearance and lid debris. Alternative grading scales and/or clinical variables associated with MGD should be addressed in future studies. PMID:22499983

  1. Reliability and Validity of Modified Algometer in Abdominal Examination

    PubMed Central

    Ko, Seok-Jae; Kim, Honggeol; Kim, Seul-Ki; Park, Kyungmo; Lee, Jeungchan; Lee, Beom-Joon; Oh, Jayoung; Lee, Kyungjin; Park, Jae-Woo

    2016-01-01

    Objective. Abdominal examination (AE) is one of the essential diagnostic methods in traditional Korean medicine that has been widely used for deciding treatment, cause, and prognosis of the disease. AE majorly depends on the experience of practitioners; therefore, standardization and quantification of AE are desperately needed. However, few studies have tried to objectify AE and established its standard. We assessed the reliability and validity of newly developed diagnostic device for AE called modified algometer (MA). Methods. Thirty-six subjects with functional dyspepsia were allocated into one of 2 groups according to gold standard of AE: epigastric discomfort without tenderness (n = 23) group or epigastric discomfort with tenderness (n = 13) group. Pressure pain threshold was evaluated at participants' epigastric region with algometer and MA. We assessed reliability and validity (sensitivity and specificity) and calculated optimal cutoff value. Results. MA showed high intertrial reliability (ICC 0.849; 0.703–0.923; P < 0.000) and validity (sensitivity: 76.92%; specificity: 60.87%), and cutoff value was 330.0 mmHg. Algometer and MA showed moderate correlation (r = 0.583, P ≤ 0.000). Conclusion. MA can be reliable and valid diagnostic device for AE and has the possibility of practical use for quantification and standardization of AE. PMID:27073401

  2. Nuclear Power Plant NDE Challenges - Past, Present, and Future

    SciTech Connect

    Doctor, S. R.

    2007-03-21

    The operating fleet of U.S. nuclear power plants was built to fossil plant standards (of workmanship, not fitness for service) and with good engineering judgment. Fortuitously, those nuclear power plants were designed using defense-in-depth concepts, with nondestructive examination (NDE) an important layer, so they can tolerate almost any component failure and still continue to operate safely. In the 30+ years of reactor operation, many material failures have occurred. Unfortunately, NDE has not provided the reliability to detect degradation prior to initial failure (breaching the pressure boundary). However, NDE programs have been improved by moving from prescriptive procedures to performance demonstrations that quantify inspection effectiveness for flaw detection probability and sizing accuracy. Other improvements include the use of risk-informed strategies to ensure that reactor components contributing the most risk receive the best and most frequent inspections. Another challenge is the recent surge of interest in building new nuclear power plants in the United States to meet increasing domestic energy demand. New construction will increase the demand for NDE but also offers the opportunity for more proactive inspections. This paper reviews the inception and evolution of NDE for nuclear power plants over the past 40 years, recounts lessons learned, and describes the needs remaining as existing plants continue operation and new construction is contemplated.

  3. NDE: An effective approach to improved reliability and safety. A technology survey. [nondestructive testing of aircraft structures

    NASA Technical Reports Server (NTRS)

    Carpenter, J. L., Jr.; Stuhrke, W. F.

    1976-01-01

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

  4. Nondestructive Evaluation (NDE) Research Progress in 1988, Proceedings From the Ninth Annual EPRI NDE Information Meeting

    SciTech Connect

    1989-05-01

    Nondestructive evaluation (NDE) research has led to improved technologies and new procedures for inspecting electric generating plant components. This review of 1988 EPRI research discusses NDE procedures for pressure vessel and containment weld examinations, assessments of the eddy-current technology for steam generators, and integrated ultrasonic techniques for examining cast austenitic stainless components.

  5. Development of NDE methods for hot gas filters.

    SciTech Connect

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

    1999-07-21

    Ceramic hot gas candle filters are currently under development for hot gas particulate cleanup in advanced coal-based power systems. The ceramic materials for these filters include nonoxide monolithic, nonoxide-fiber-reinforced composites, and nonoxide reticulated foam. A concern is the lack of reliable data on which to base decisions for reusing or replacing hot gas filters during plant shutdowns. The work in this project is aimed at developing nondestructive evaluation (FIDE) technology to allow detection, and determination of extent, 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 temperature. Although in-situ NDE methods are desirable in order to avoid disassembly of the candle filter vessels, the current vessel designs, the presence of filter cakes and possible ash bridging, and the state of NDE technology prevent this. Candle filter producers use a variety of NDE methods to ensure as-produced quality. While impact acoustic resonance offers initial promise for examining new as-produced filters and for detecting damage in some monolithic filters when removed from service, it presents difficulties in data interpretation, it lacks localization capability, and its applicability to composites has yet to be demonstrated. Additional NDE technologies being developed and evaluated in this program and whose applicability to both monolithics and composites has been demonstrated include (a) full-scale thermal imaging for analyzing thermal property variations; (b) fret, high-spatial-resolution X-ray imaging for detecting density variations and dimensional changes; (c) air-coupled ultrasonic methods for determining through-thickness compositional variations; and (d) acoustic emission technology with mechanical loading for detecting localized bulk damage. New and exposed clay-bonded SiC filters and CVI-SiC composite filters have been tested with

  6. Videotape Reliability: A Method of Evaluation of a Clinical Performance Examination.

    ERIC Educational Resources Information Center

    And Others; Liu, Philip

    1980-01-01

    A method of statistically analyzing clinical performance examinations for reliability and the application of this method in determining the reliability of two examinations of skill in administering anesthesia are described. Videotaped performances for the Spinal Anesthesia Skill Examination and the Anesthesia Setup and Machine Checkout Examination…

  7. Interrater reliability of quantitative ultrasound using force feedback among examiners with varied levels of experience

    PubMed Central

    Ismail, Catheeja; Monfaredi, Reza; Hernandez, Haniel J.; Pennington, Donte; Woletz, Paula; McIntosh, Valerie; Adams, Bernadette; Blackman, Marc R.

    2016-01-01

    Background. Quantitative ultrasound measures are influenced by multiple external factors including examiner scanning force. Force feedback may foster the acquisition of reliable morphometry measures under a variety of scanning conditions. The purpose of this study was to determine the reliability of force-feedback image acquisition and morphometry over a range of examiner-generated forces using a muscle tissue-mimicking ultrasound phantom. Methods. Sixty material thickness measures were acquired from a muscle tissue mimicking phantom using B-mode ultrasound scanning by six examiners with varied experience levels (i.e., experienced, intermediate, and novice). Estimates of interrater reliability and measurement error with force feedback scanning were determined for the examiners. In addition, criterion-based reliability was determined using material deformation values across a range of examiner scanning forces (1–10 Newtons) via automated and manually acquired image capture methods using force feedback. Results. All examiners demonstrated acceptable interrater reliability (intraclass correlation coefficient, ICC = .98, p < .001) for material thickness measures obtained using force feedback. Individual examiners exhibited acceptable reliability with the criterion-based reference measures (ICC > .90, p < .001), independent of their level of experience. The measurement error among all examiners was 1.5%–2.9% across all applied stress conditions. Conclusion. Manual image capture with force feedback may aid the reliability of morphometry measures across a range of examiner scanning forces, and allow for consistent performance among examiners with differing levels of experience. PMID:27366647

  8. Overview of the program to assess the reliability of emerging nondestructive techniques open testing and study of flaw type effect on NDE response

    NASA Astrophysics Data System (ADS)

    Meyer, Ryan M.; Komura, Ichiro; Kim, Kyung-cho; Zetterwall, Tommy; Cumblidge, Stephen E.; Prokofiev, Iouri

    2016-02-01

    In February 2012, the U.S. Nuclear Regulatory Commission (NRC) executed agreements with VTT Technical Research Centre of Finland, Nuclear Regulatory Authority of Japan (NRA, former JNES), Korea Institute of Nuclear Safety (KINS), Swedish Radiation Safety Authority (SSM), and Swiss Federal Nuclear Safety Inspectorate (ENSI) to establish the Program to Assess the Reliability of Emerging Nondestructive Techniques (PARENT). The goal of PARENT is to investigate the effectiveness of current emerging and perspective novel nondestructive examination procedures and techniques to find flaws in nickel-alloy welds and base materials. This is done by conducting a series of open and blind international round-robin tests on a set of large-bore dissimilar metal welds (LBDMW), small-bore dissimilar metal welds (SBDMW), and bottom-mounted instrumentation (BMI) penetration weld test blocks. The purpose of blind testing is to study the reliability of more established techniques and included only qualified teams and procedures. The purpose of open testing is aimed at a more basic capability assessment of emerging and novel technologies. The range of techniques applied in open testing varied with respect to maturity and performance uncertainty and were applied to a variety of simulated flaws. This paper will include a brief overview of the PARENT blind and open testing techniques and test blocks and present some of the blind testing results.

  9. Subjective Scoring of Divergent Thinking: Examining the Reliability of Unusual Uses, Instances, and Consequences Tasks

    ERIC Educational Resources Information Center

    Silvia, Paul J.

    2011-01-01

    The present research examined the reliability of three types of divergent thinking tasks (unusual uses, instances, consequences/implications) and two types of subjective scoring (an average across all responses vs. the responses people chose as their top-two responses) within a latent variable framework, using the maximal-reliability "H"…

  10. Reliability and Validity of a Breast Self-Examination Proficiency Rating Instrument.

    ERIC Educational Resources Information Center

    Wood, Robin Y.

    1994-01-01

    The reliability and validity of a newly constructed instrument, the Breast Self-Examination Proficiency Rating Instrument, was tested with 84 instructed and 80 uninstructed nursing students. Results support beginning reliability and preliminary validity when the instrument is used in a controlled setting. (SLD)

  11. Ensuring reliability in UK written tests of general practice: the MRCGP examination 1998-2003.

    PubMed

    Munro, Neil; Denney, Mei Ling; Rughani, Amar; Foulkes, John; Wilson, Andrew; Tate, Peter

    2005-01-01

    Reliability in written examinations is taken very seriously by examination boards and candidates alike. Within general education many factors influence reliability including variations between markers, within markers, within candidates and within teachers. Mechanisms designed to overcome, or at least minimize, the impact of such variables are detailed. Methods of establishing reliability are also explored in the context of a range of assessment situations. In written tests of general practice within the Membership of the Royal College of General Practitioner (MRCGP) examination considerable effort has put been put into achieving acceptable levels of reliability. Current mechanisms designed to ensure high reliability are described and related to the evolution of the written component of the examination. In addition to description of marker selection and training, question development including construct a detailed example of specific and generic marking schedules is provided. Examination results for the Written Paper of the MRCGP from 1998 to 2003 are reported including Cronbach's alpha coefficients and standard error of measurements, mean scores (and SD) and pass rates. In addition individual discrimination scores for each question in the October 2002 paper are shown. Consistent high reliability of the written component of the MRCGP examination provides valuable lessons in terms of selection, training and monitoring of markers as well as practical methods of moderating factors affecting candidate variability. The challenge for examination developers is to carry these important lessons forward into a modernized assessment structure of UK general practice. PMID:16147769

  12. NASA NDE Program

    NASA Technical Reports Server (NTRS)

    Generazio, Ed; Burke, Eric

    2015-01-01

    The current activities in the National Aeronautics and Space Administration Nondestructive Evaluation (NDE) Program are presented. The topics covered include organizational communications, orbital weld inspection, electric field imaging, fracture critical probability of detection validation, monitoring of thermal protection systems, physical and document standards, image quality indicators, integrity of composite pressure vessels, and NDE for additively manufactured components.

  13. Developing NDE Techniques for Orion Crew Module

    NASA Technical Reports Server (NTRS)

    Parker, Don; Starr, Stan; Youngquist, Robert

    2009-01-01

    Project: The Orion Crew Module (CM) and Service Module (SM) subsystems will require approximately 870 tube welds to be fabricated onsite at KSC O&C High Bay. A quick and reliable NDE technique is required to ensure efficient assembly and superior weld quality.

  14. Directed Design of Experiments (DOE) for Determining Probability of Detection (POD) Capability of NDE Systems (DOEPOD)

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    2007-01-01

    This viewgraph presentation reviews some of the problems that are encountered by designers of Non-Destructive Examination (NDE) have in determining the probability of detection. According to the author "[the] NDE community should not blindly accept statistical results due to lack of knowledge." This is an attempt to bridge the gap between people doing NDE, and statisticians.

  15. Steam generator tubing NDE performance

    SciTech Connect

    Henry, G.; Welty, C.S. Jr.

    1997-02-01

    Steam generator (SG) non-destructive examination (NDE) is a fundamental element in the broader SG in-service inspection (ISI) process, a cornerstone in the management of PWR steam generators. Based on objective performance measures (tube leak forced outages and SG-related capacity factor loss), ISI performance has shown a continually improving trend over the years. Performance of the NDE element is a function of the fundamental capability of the technique, and the ability of the analysis portion of the process in field implementation of the technique. The technology continues to improve in several areas, e.g. system sensitivity, data collection rates, probe/coil design, and data analysis software. With these improvements comes the attendant requirement for qualification of the technique on the damage form(s) to which it will be applied, and for training and qualification of the data analysis element of the ISI process on the field implementation of the technique. The introduction of data transfer via fiber optic line allows for remote data acquisition and analysis, thus improving the efficiency of analysis for a limited pool of data analysts. This paper provides an overview of the current status of SG NDE, and identifies several important issues to be addressed.

  16. Oral Assessment and Postgraduate Medical Examinations: Establishing Conditions for Validity, Reliability and Fairness

    ERIC Educational Resources Information Center

    Memon, Muhammed Ashraf; Joughin, Gordon Rowland; Memon, Breda

    2010-01-01

    The purpose of this review was to examine the practice of oral assessment in postgraduate medical education in the context of the core assessment constructs of validity, reliability and fairness. Although oral assessment has a long history in the certification process of medical specialists and is a well-established part of such proceedings for a…

  17. Examining the Reliability and Validity of Clinician Ratings on the Five-Factor Model Score Sheet

    ERIC Educational Resources Information Center

    Few, Lauren R.; Miller, Joshua D.; Morse, Jennifer Q.; Yaggi, Kirsten E.; Reynolds, Sarah K.; Pilkonis, Paul A.

    2010-01-01

    Despite substantial research use, measures of the five-factor model (FFM) are infrequently used in clinical settings due, in part, to issues related to administration time and a reluctance to use self-report instruments. The current study examines the reliability and validity of the Five-Factor Model Score Sheet (FFMSS), which is a 30-item…

  18. Reliability analysis of the objective structured clinical examination using generalizability theory

    PubMed Central

    Trejo-Mejía, Juan Andrés; Sánchez-Mendiola, Melchor; Méndez-Ramírez, Ignacio; Martínez-González, Adrián

    2016-01-01

    Background The objective structured clinical examination (OSCE) is a widely used method for assessing clinical competence in health sciences education. Studies using this method have shown evidence of validity and reliability. There are no published studies of OSCE reliability measurement with generalizability theory (G-theory) in Latin America. The aims of this study were to assess the reliability of an OSCE in medical students using G-theory and explore its usefulness for quality improvement. Methods An observational cross-sectional study was conducted at National Autonomous University of Mexico (UNAM) Faculty of Medicine in Mexico City. A total of 278 fifth-year medical students were assessed with an 18-station OSCE in a summative end-of-career final examination. There were four exam versions. G-theory with a crossover random effects design was used to identify the main sources of variance. Examiners, standardized patients, and cases were considered as a single facet of analysis. Results The exam was applied to 278 medical students. The OSCE had a generalizability coefficient of 0.93. The major components of variance were stations, students, and residual error. The sites and the versions of the tests had minimum variance. Conclusions Our study achieved a G coefficient similar to that found in other reports, which is acceptable for summative tests. G-theory allows the estimation of the magnitude of multiple sources of error and helps decision makers to determine the number of stations, test versions, and examiners needed to obtain reliable measurements. PMID:27543188

  19. The Reliability of Results from National Tests, Public Examinations, and Vocational Qualifications in England

    ERIC Educational Resources Information Center

    He, Qingping; Opposs, Dennis

    2012-01-01

    National tests, public examinations, and vocational qualifications in England are used for a variety of purposes, including the certification of individual learners in different subject areas and the accountability of individual professionals and institutions. However, there has been ongoing debate about the reliability and validity of their…

  20. The reliability, validity, and usefulness of the Objective Structured Clinical Examination (OSCE) in dental education

    NASA Astrophysics Data System (ADS)

    Graham, Roseanna

    This study evaluated the reliability, validity, and educational usefulness of a comprehensive, multidisciplinary Objective Structured Clinical Examination (OSCE) in dental education. The OSCE was administered to dental students at the Columbia University College of Dental Medicine (CDM) before they entered clinical training. Participants in this study included CDM's class of 2010 which consisted of 78 students. The overall reliability of the examination was measured via calculation of Cronbach's alpha. Content validity was examined through evaluation of the OSCE by three experienced clinical faculty members. Predictive validity was evaluated by correlating student grades on the OSCE to future clinical performance as measured by number of clinical points achieved during the third year of training. Student perceptions regarding the educational usefulness of the examination were evaluated through a 12-question Liken-type survey and focus group interviews analyzed using a phenomenological approach. Findings of the study indicated the OSCE was a highly reliable examination (alpha=0.86) with high content validity and a moderately high correlation to future clinical performance (r=.614, p<.0001). Overall, student perceptions of the educational usefulness of the OSCE were positive as based on their responses to a 5-point Likert scale (1=strongly disagree and 5=strongly agree). They reported that the exam required the ability to think critically and problem-solve (4.0 +/- 0.85), assessed clinically relevant skills (4.59 +/- 0.69), helped identify clinical weaknesses (4.16 +/- 0.90), and was a learning experience (4.58 +/- 0.84). Findings from the qualitative portion of the study identified four main themes including the student perception that the OSCE is a unique assessment experience that required integration and application of knowledge. Recommendations for the use of the OSCE to improve clinical teaching and the implications of this study relating to the expanded use of

  1. [The Reliability of Measurement Methods for Medical Examinations and Health Screening].

    PubMed

    Hosogaya, Shigemi

    2016-03-01

    Clinical laboratory data used in medical examinations and health screening need to have a guaranteed analytical reliability. To ensure the reliability of measurement data, each constituent is required to be compatible with its traceability chain, and any constituent whose traceability chain has yet to be established is required to be appropriately harmonized in the current measurement system. The inter-laboratory reproducibility of standardized measurement values obtained from the external quality assessments conducted by the Japan Medical Association and Japanese Association of Medical Technologists was estimated to evaluate the analytical reliability of clinical tests in Japan. The estimated inter-laboratory reproducibility was then compared with the permissible error limits which have been reported domestically and internationally based on inter- and intra-individual biological variations of healthy subjects. The results showed that most of the measurement uncertainties were sufficiently lower than the permissible limits. This study proposes that the measurement uncertainty of the standardized measurement method has the potential to be a new assessment standard for analytical reliability. PMID:27363220

  2. The Colorado Haemophilia Paediatric Joint Physical Examination Scale: normal values and interrater reliability.

    PubMed

    Hacker, M R; Funk, S M; Manco-Johnson, M J

    2007-01-01

    Persons with haemophilia often experience their first joint haemorrhage in early childhood. Recurrent bleeding into a joint may lead to significant morbidity, specifically haemophilic arthropathy. Early identification of the onset and progression of joint damage is critical to preserving joint structure and function. Physical examination is the most feasible approach to monitor joint health. Our group developed the Colorado Haemophilia Paediatric Joint Physical Examination Scale to identify earlier signs of joint degeneration and incorporate developmentally appropriate tasks for assessing joint function in young children. This study's objectives were to establish normal ranges for this scale and assess interrater reliability. The ankles, knees and elbows of 72 healthy boys aged 1 through 7 years were evaluated by a physical therapist to establish normal ranges. Exactly 10 boys in each age category from 2 to 7 years were evaluated by a second physical therapist to determine interrater reliability. The original scale was modified to account for the finding that mild angulation in the weight-bearing joints is developmentally normal. The interrater reliability of the scale ranged from fair to good, underscoring the need for physical therapists to have specific training in the orthopaedic assessment of very young children and the measurement error inherent in the goniometer. Modifications to axial alignment scoring will allow the scale to distinguish healthy joints from those suffering frequent haemarthroses. PMID:17212728

  3. RCC NDE Update

    NASA Technical Reports Server (NTRS)

    Hernandez, Jose M.

    2004-01-01

    This slide presentation reviews non-destructive evaluation (NDE) techniques of Reinforced Carbon-Carbon (RCC) materials and the progress involved in bringing the technology to technological maturity. Included is information about the test specimens, thermographic, ultrasonic, eddy current, and radiographic inspection of RCC materials.

  4. Developing an estimate of daily cumulative loading for the knee: examining test-retest reliability.

    PubMed

    Robbins, Shawn M K; Birmingham, Trevor B; Jones, Gareth R; Callaghan, Jack P; Maly, Monica R

    2009-11-01

    Although the knee adduction moment during gait is a valid and reliable proxy for the dynamic load on the medial compartment of the knee, it represents exposure to loading during one stride only. In contrast, a measure that incorporates both the nature and frequency of loading throughout daily activities might provide additional insight into the effects of cumulative knee loading. The purpose of this study was to introduce a new representation of daily cumulative knee loading and examine its test-retest reliability. Thirty healthy adults participated. Cumulative knee loading was calculated on two testing periods from the mean external knee adduction moment stance phase impulse, measured with a three-dimensional motion capture system over five walking trials, and mean steps/day, measured with a unidimensional accelerometer over one week. Analysis for test-retest reliability included Bland-Altman graphs, intraclass correlation coefficients (ICC 2,1) and standard errors of measurements (SEM). The ICC values for cumulative knee loading, adduction impulse and steps/day ranged from 0.84 to 0.89. Bland-Altman plots suggested daily cumulative knee loading and steps/day measures were less reliable at higher values. The SEM values were 9.67 kNm s, 1.45 Nm s and 1043 steps/day for cumulative knee loading, adduction impulse and steps/day, respectively. Daily cumulative knee loading is reliable and provides a stable measure of the total exposure to knee loading. These findings support further study of cumulative knee loading to determine its potential clinical importance. PMID:19692246

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

    SciTech Connect

    Not Available

    1991-01-01

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

  6. A limited assessment of the ASEP human reliability analysis procedure using simulator examination results

    SciTech Connect

    Gore, B.R.; Dukelow, J.S. Jr.; Mitts, T.M.; Nicholson, W.L.

    1995-10-01

    This report presents a limited assessment of the conservatism of the Accident Sequence Evaluation Program (ASEP) human reliability analysis (HRA) procedure described in NUREG/CR-4772. In particular, the, ASEP post-accident, post-diagnosis, nominal HRA procedure is assessed within the context of an individual`s performance of critical tasks on the simulator portion of requalification examinations administered to nuclear power plant operators. An assessment of the degree to which operator perforn:Lance during simulator examinations is an accurate reflection of operator performance during actual accident conditions was outside the scope of work for this project; therefore, no direct inference can be made from this report about such performance. The data for this study are derived from simulator examination reports from the NRC requalification examination cycle. A total of 4071 critical tasks were identified, of which 45 had been failed. The ASEP procedure was used to estimate human error probability (HEP) values for critical tasks, and the HEP results were compared with the failure rates observed in the examinations. The ASEP procedure was applied by PNL operator license examiners who supplemented the limited information in the examination reports with expert judgment based upon their extensive simulator examination experience. ASEP analyses were performed for a sample of 162 critical tasks selected randomly from the 4071, and the results were used to characterize the entire population. ASEP analyses were also performed for all of the 45 failed critical tasks. Two tests were performed to assess the bias of the ASEP HEPs compared with the data from the requalification examinations. The first compared the average of the ASEP HEP values with the fraction of the population actually failed and it found a statistically significant factor of two bias on the average.

  7. Examining the Validity and Reliability of the ABC-6 in Underserved Older Adults.

    PubMed

    Skipper, Antonius; Ellis, Rebecca

    2015-09-01

    Losing confidence in the ability to maintain balance can be more debilitating than a fall; therefore, the accurate measurement of balance confidence is critical. The purpose of this study was to examine the validity and reliability of the ABC-6, a shortened version of the Activities-specific Balance Confidence scale (ABC), among underserved older adults. The final sample included 251 older adults (M age = 71.2 years, SD = 8.9; 72.1% African Americans, 62.5% low-income, 61% low-education). Participants completed assessments of multiple falls risk factors, physical activity, and balance confidence. The ABC-6 had excellent internal consistency reliability, substantial intraclass correlations, and significant moderate to large correlations with physical activity, mobility, balance, and total falls risk. It also demonstrated the ability to discriminate between fallers and nonfallers, and it was a significant predictor of total falls risk. The ABC-6 was a valid and reliable measure of balance confidence among underserved older adults. PMID:24652895

  8. NDE Assessment of PWSCC in Control Rod Drive Mechanism Housings

    SciTech Connect

    Doctor, Steven R.; Cumblidge, Stephen E.; Schuster, George J.; Harris, Rob V.; Crawford, Susan L.

    2006-11-01

    Studies being conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington are focused on assessing the effectiveness of Nondestructive examination (NDE) techniques for inspecting control rod drive mechanism (CRDM) nozzles and J-groove weldments. The primary objective of this work is to provide information to the United States Nuclear Regulatory Commission (US NRC) on the effectiveness of NDE methods as related to the in-service inspection of CRDM nozzles and J-groove weldments, and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies. In describing two CRDM assemblies removed from service, decontaminated, and then used in a series of NDE measurements, this paper will address the following questions: 1) What did each technique detect?, 2) What did each technique miss?, 3) How accurately did each technique characterize the detected flaws? Two CRDM assemblies including the CRDM nozzle, the J-groove weld, buttering, and a portion of the ferritic head material were selected for this study. One contained suspected PWSCC, based on in-service inspection data and through-wall leakage; the other contained evidence suggesting through-wall leakage, but this was unconfirmed. The selected NDE measurements follow standard industry techniques for conducting in-service inspections of CRDM nozzles and the crown of the J-groove welds and buttering. In addition, laboratory based NDE methods were employed to conduct inspections of the CRDM assemblies, with particular emphasis on inspecting the J-groove weld and buttering. This paper will also describe the NDE methods used and discuss the NDE results. Future work will involve using the results from these NDE studies to guide the development of a destructive characterization plan to reveal the crack morphology and a comparison of the degradation found by the destructive evaluation with the recorded NDE responses.

  9. An Examination of the Reliability of Scores from Zuckerman's Sensation Seeking Scales, Form V.

    ERIC Educational Resources Information Center

    Deditius-Island, Heide K.; Caruso, John C.

    2002-01-01

    Conducted a reliability generalization study on Zuckerman's Sensation Seeking Scale (M. Zuckerman and others, 1964) using 113 reliability coefficients from 21 published studies. The reliability of scores was marginal for four of the five scales, and low for the other. Mean age of subjects has a significant relationship with score reliability. (SLD)

  10. Examining the Reliability and Validity of Clinician Ratings on the Five-Factor Model Score Sheet

    PubMed Central

    Few, Lauren R.; Miller, Joshua D.; Morse, Jennifer Q.; Yaggi, Kirsten E.; Reynolds, Sarah K.; Pilkonis, Paul A.

    2013-01-01

    Despite substantial research use, measures of the five-factor model (FFM) are infrequently used in clinical settings due, in part, to issues related to administration time and a reluctance to use self-report instruments. The current study examines the reliability and validity of the Five-Factor Model Score Sheet (FFMSS), which is a 30-item clinician rating form designed to assess the five domains and 30 facets of one conceptualization of the FFM. Studied in a sample of 130 outpatients, clinical raters demonstrated reasonably good interrater reliability across personality profiles and the domains manifested good internal consistency with the exception of Neuroticism. The FFMSS ratings also evinced expected relations with self-reported personality traits (e.g., FFMSS Extraversion and Schedule for Nonadaptive and Adaptive Personality Positive Temperament) and consensus-rated personality disorder symptoms (e.g., FFMSS Agreeableness and Narcissistic Personality Disorder). Finally, on average, the FFMSS domains were able to account for approximately 50% of the variance in domains of functioning (e.g., occupational, parental) and were even able to account for variance after controlling for Axis I and Axis II pathology. Given these findings, it is believed that the FFMSS holds promise for clinical use. PMID:20519735

  11. NDE applications in microelectronic industries

    NASA Astrophysics Data System (ADS)

    Meyendorf, N.; Oppermann, M.; Krueger, P.; Roellig, M.; Wolter, K. J.

    2016-04-01

    New concepts in assembly technology boost our daily life in an unknown way. High end semiconductor industry today deals with functional structures down to a few nanometers. ITRS roadmap predicts an ongoing decrease of the "DRAM half pitch" over the next decade. Packaging of course is not intended to realize pitches at the nanometer scale, but has to face the challenges of integrating such semiconductor devices with smallest pitch and high pin counts into systems. Advanced techniques of nondestructive evaluation (NDE) with resolutions in volume better than 1 micrometer vixen size are urgently needed for the safety and reliability of electronic systems, especially those that are used in long living applications. The development speed of integrated circuits is still very high and is not expected to decrease in the next future. The integration density of microelectronic devices is increasing, the dimensions become smaller and the number of I/O's is getting higher. The development of new types of packages must be done with respect to reliability issues. Potential damage sources must be identified and finally avoided in the new packages. In power electronics production the condition monitoring receives a lot of interest to avoid electrical shortcuts, dead solder joints and interface cracking. It is also desired to detect and characterize very small defects like transportation phenomenon or Kirkendall voids. For this purpose, imaging technologies with resolutions in the sub-micron range are required.

  12. Precise thermal NDE for quantifying structural damage

    SciTech Connect

    Del Grande, N.K.; Durbin, P.F.

    1995-09-18

    The authors demonstrated a fast, wide-area, precise thermal NDE imaging system to quantify aircraft corrosion damage, such as percent metal loss, above a threshold of 5% with 3% overall uncertainties. The DBIR precise thermal imaging and detection method has been used successfully to characterize defect types, and their respective depths, in aircraft skins, and multi-layered composite materials used for wing patches, doublers and stiffeners. This precise thermal NDE inspection tool has long-term potential benefits to evaluate the structural integrity of airframes, pipelines and waste containers. They proved the feasibility of the DBIR thermal NDE imaging system to inspect concrete and asphalt-concrete bridge decks. As a logical extension to the successful feasibility study, they plan to inspect a concrete bridge deck from a moving vehicle to quantify the volumetric damage within the deck and the percent of the deck which has subsurface delaminations. Potential near-term benefits are in-service monitoring from a moving vehicle to inspect the structural integrity of the bridge deck. This would help prioritize the repair schedule for a reported 200,000 bridge decks in the US which need substantive repairs. Potential long-term benefits are affordable, and reliable, rehabilitation for bridge decks.

  13. Fiber optic sensing for ultrasonic NDE

    SciTech Connect

    Dudderar, T.D.; Burger, C.P.; Gilbert, J.A.; Smith, J.A.; Peters, B.R.

    1987-09-01

    An innovative approach to nondestructive evaluation (NDE) using noncontacting optical sensors has demonstrated. In this effort a single mode optical fiber interferometer (OFI) was used to sense the presence and form of Rayleigh waves traveling along the surface of a steel test bar at a velocity of nearly 3mm/..mu.. s. Acousto-optic time-domain data was successfully used to detect the presence and locate the position of a test flaw (a machined slot) in the bar, and spectrum analysis was used to estimate its geometry and size. This approach has many potential applications in the ultrasonic evaluation of real flaws in structures with complex geometries. Coupled with the authors' earlier work demonstrating the feasibility of generating acoustic waves in metals using laser light pulses transmitted through the fiber optic probes, this latest achievement points to the development of a fully noncontacting, fiber optic based thermal-acousto-photonic (TAP) NDE system, with potential applications to the reliability testing of many important structures where composition, scale, geometry, or restricted access preclude the use of conventional NDE techniques.

  14. Experimental validation of ultrasonic NDE simulation software

    NASA Astrophysics Data System (ADS)

    Dib, Gerges; Larche, Michael; Diaz, Aaron A.; Crawford, Susan L.; Prowant, Matthew S.; Anderson, Michael T.

    2016-02-01

    Computer modeling and simulation is becoming an essential tool for transducer design and insight into ultrasonic nondestructive evaluation (UT-NDE). As the popularity of simulation tools for UT-NDE increases, it becomes important to assess their reliability to model acoustic responses from defects in operating components and provide information that is consistent with in-field inspection data. This includes information about the detectability of different defect types for a given UT probe. Recently, a cooperative program between the Electrical Power Research Institute and the U.S. Nuclear Regulatory Commission was established to validate numerical modeling software commonly used for simulating UT-NDE of nuclear power plant components. In the first phase of this cooperative, extensive experimental UT measurements were conducted on machined notches with varying depth, length, and orientation in stainless steel plates. Then, the notches were modeled in CIVA, a semi-analytical NDE simulation platform developed by the French Commissariat a l'Energie Atomique, and their responses compared with the experimental measurements. Discrepancies between experimental and simulation results are due to either improper inputs to the simulation model, or to incorrect approximations and assumptions in the numerical models. To address the former, a variation study was conducted on the different parameters that are required as inputs for the model, specifically the specimen and transducer properties. Then, the ability of simulations to give accurate predictions regarding the detectability of the different defects was demonstrated. This includes the results in terms of the variations in defect amplitude indications, and the ratios between tip diffracted and specular signal amplitudes.

  15. NDE detectability of fatigue type cracks in high strength alloys

    NASA Technical Reports Server (NTRS)

    Christner, B. K.; Rummel, W. D.

    1983-01-01

    Specimens suitable for investigating the reliability of production nondestructive evaluation (NDE) to detect tightly closed fatigue cracks in high strength alloys representative of those materials used in spacecraft engine/booster construction were produced. Inconel 718 was selected as representative of nickel base alloys and Haynes 188 was selected as representative of cobalt base alloys used in this application. Cleaning procedures were developed to insure the reusability of the test specimens and a flaw detection reliability assessment of the fluorescent penetrant inspection method was performed using the test specimens produced to characterize their use for future reliability assessments and to provide additional NDE flaw detection reliability data for high strength alloys. The statistical analysis of the fluorescent penetrant inspection data was performed to determine the detection reliabilities for each inspection at a 90% probability/95% confidence level.

  16. NDE: A key to engine rotor life prediction

    NASA Technical Reports Server (NTRS)

    Doherty, J. E.

    1977-01-01

    A key ingredient in the establishment of safe life times for critical components is the means of reliably detecting flaws which may potentially exist. Currently used nondestructive evaluation procedures are successful in detecting life limiting defects; however, the development of automated and computer aided NDE technology permits even greater assurance of flight safety.

  17. Second Conference on NDE for Aerospace Requirements

    NASA Technical Reports Server (NTRS)

    Woodis, Kenneth W. (Compiler); Bryson, Craig C. (Compiler); Workman, Gary L. (Compiler)

    1990-01-01

    Nondestructive evaluation and inspection procedures must constantly improve rapidly in order to keep pace with corresponding advances being made in aerospace material and systems. In response to this need, the 1989 Conference was organized to provide a forum for discussion between the materials scientists, systems designers, and NDE engineers who produce current and future aerospace systems. It is anticipated that problems in current systems can be resolved more quickly and that new materials and structures can be designed and manufactured in such a way as to be more easily inspected and to perform reliably over the life cycle of the system.

  18. The Mindful Attention Awareness Scale: Further Examination of Dimensionality, Reliability, and Concurrent Validity Estimates.

    PubMed

    Osman, Augustine; Lamis, Dorian A; Bagge, Courtney L; Freedenthal, Stacey; Barnes, Sean M

    2016-01-01

    We examined the factor structure and psychometric properties of the Mindful Attention Awareness Scale (MAAS) in a sample of 810 undergraduate students. Using common exploratory factor analysis (EFA), we obtained evidence for a 1-factor solution (41.84% common variance). To confirm unidimensionality of the 15-item MAAS, we conducted a 1-factor confirmatory factor analysis (CFA). Results of the EFA and CFA, respectively, provided support for a unidimensional model. Using differential item functioning analysis methods within item response theory modeling (IRT-based DIF), we found that individuals with high and low levels of nonattachment responded similarly to the MAAS items. Following a detailed item analysis, we proposed a 5-item short version of the instrument and present descriptive statistics and composite score reliability for the short and full versions of the MAAS. Finally, correlation analyses showed that scores on the full and short versions of the MAAS were associated with measures assessing related constructs. The 5-item MAAS is as useful as the original MAAS in enhancing our understanding of the mindfulness construct. PMID:26560259

  19. Reliability Generalization: An Examination of the Positive Affect and Negative Affect Schedule

    ERIC Educational Resources Information Center

    Leue, Anja; Lange, Sebastian

    2011-01-01

    The assessment of positive affect (PA) and negative affect (NA) by means of the Positive Affect and Negative Affect Schedule has received a remarkable popularity in the social sciences. Using a meta-analytic tool--namely, reliability generalization (RG)--population reliability scores of both scales have been investigated on the basis of a random…

  20. 40-in. OMS Kevlar(Registered Trademark) COPV S/N 007 Stress Rupture Test NDE

    NASA Technical Reports Server (NTRS)

    Saulsberry, Regor; Greene, Nate; Forth, Scott; Leifeste, Mark; Gallus, Tim; Yoder, Tommy; Keddy, Chris; Mandaras, Eric; Wincheski, Buzz; Williams, Philip; Russell, Richard; Eldridge, Jeff

    2010-01-01

    The presentation examines pretest nondestructive evaluation (NDE), including external/internal visual inspection, raman spectroscopy, laser shearography, and laser profilometry; real-time NDE including eddy current, acoustic emission (AE), and real-time portable raman spectroscopy; and AE application to carbon/epoxy composite overwrapped pressure vessels.

  1. Technical Letter Report - Preliminary Assessment of NDE Methods on Inspection of HDPE Butt Fusion Piping Joints for Lack of Fusion

    SciTech Connect

    Crawford, Susan L.; Cumblidge, Stephen E.; Doctor, Steven R.; Hall, Thomas E.; Anderson, Michael T.

    2008-05-29

    The U.S. Nuclear Regulatory Commission (NRC) has a multi-year program at the Pacific Northwest National Laboratory (PNNL) to provide engineering studies and assessments of issues related to the use of nondestructive evaluation (NDE) methods for the reliable inspection of nuclear power plant components. As part of this program, there is a subtask 2D that was set up to address an assessment of issues related to the NDE of high density polyethylene (HDPE) butt fusion joints. This work is being driven by the nuclear industry wanting to employ HDPE materials in nuclear power plant systems. This being a new material for use in nuclear applications, there are a number of issues related to its use and potential problems that may evolve. The industry is pursuing ASME Code Case N-755 entitled “Use of Polyethylene (PE) Plastic Pipe for Section III, Division 1, Construction and Section XI Repair/Replacement Activities” that contains the requirements for nuclear power plant applications of HDPE. This Code Case requires that inspections be performed after the fusion joint is made by visually examining the bead that is formed and conducting a pressure test of the joint. These tests are only effective in general if gross through-wall flaws exist in the fusion joint. The NRC wants to know whether a volumetric inspection can be conducted on the fusion joint that will reliably detect lack-of-fusion conditions that may be produced during joint fusing. The NRC has requested that the work that PNNL is conducting be provided to assist them in resolving this inspection issue of whether effective volumetric NDE can be conducted to detect lack of fusion (LOF) in the butt HDPE joints. PNNL had 24 HDPE pipe specimens manufactured of 3408 material to contain LOF conditions that could be used to assess the effectiveness of NDE in detecting the LOF. Basic ultrasonic material properties were measured and used to guide the use of phased arrays and time-of-flight diffraction (TOFD) work that

  2. NDE of advanced ceramics

    NASA Technical Reports Server (NTRS)

    Klima, S. J.

    1986-01-01

    Radiographic, ultrasonic, and scanning laser acoustic microscopy (SLAM) techniques were used to characterize silicon nitride and silicon carbide modulus-of-rupture test specimens in various stages of fabrication. Conventional and microfocus X-ray techniques were found capable of detecting minute high-density inclusions in as-received powders, green compacts, and fully densified specimens. Significant density gradients in sintered bars were observed by radiography, ultrasonic velocity, and SLAM. Ultrasonic attenuation was found sensitive to microstructural variations due to grain and void morphology and distribution. SLAM was capable also of detecting voids, inclusions, and cracks in finished test bars. Consideration is given to the potential for applying thermoacoustic microscopy techniques to green and densified ceramics. Some limitations and the detection probability statistics of the aforementioned nondestructive evaluation (NDE) processes are also discussed.

  3. Reliability of Health Information on the Internet: An Examination of Experts' Ratings

    PubMed Central

    Craigie, Mark; Loader, Brian; Burrows, Roger

    2002-01-01

    Background The use of medical experts in rating the content of health-related sites on the Internet has flourished in recent years. In this research, it has been common practice to use a single medical expert to rate the content of the Web sites. In many cases, the expert has rated the Internet health information as poor, and even potentially dangerous. However, one problem with this approach is that there is no guarantee that other medical experts will rate the sites in a similar manner. Objectives The aim was to assess the reliability of medical experts' judgments of threads in an Internet newsgroup related to a common disease. A secondary aim was to show the limitations of commonly-used statistics for measuring reliability (eg, kappa). Method The participants in this study were 5 medical doctors, who worked in a specialist unit dedicated to the treatment of the disease. They each rated the information contained in newsgroup threads using a 6-point scale designed by the experts themselves. Their ratings were analyzed for reliability using a number of statistics: Cohen's kappa, gamma, Kendall's W, and Cronbach's alpha. Results Reliability was absent for ratings of questions, and low for ratings of responses. The various measures of reliability used gave conflicting results. No measure produced high reliability. Conclusions The medical experts showed a low agreement when rating the postings from the newsgroup. Hence, it is important to test inter-rater reliability in research assessing the accuracy and quality of health-related information on the Internet. A discussion of the different measures of agreement that could be used reveals that the choice of statistic can be problematic. It is therefore important to consider the assumptions underlying a measure of reliability before using it. Often, more than one measure will be needed for "triangulation" purposes. PMID:11956034

  4. Reference Artifacts for NDE

    SciTech Connect

    Bono, M; Hibbard, R; Martz, H E

    2003-02-11

    Two reference artifacts will be fabricated for this study. One of the artifacts will have a cylindrical geometry and will contain features similar to those on an SNRT target. The second artifact will have a spherical geometry and will contain features similar to those on a Double Shell target. The artifacts were designed for manufacturability and to provide a range of features that can be measured using NDE methods. The cylindrical reference artifact is illustrated in Figure 1. This artifact consists of a polystyrene body containing two steps and a machined slot, into which will fit a tracer made of doped polystyrene. The polystyrene body contains several grooves and can be fabricated entirely on a diamond turning machine. The body can be machined by turning a PS rod to a diameter slightly greater than the finished diameter of 2 mm. The part can be moved off-axis to face it off and to machine the steps, slot, and grooves. The tracer contains a drilled hole and a milled slot, which could be machined with a single setup on a milling machine. Once assembled, the artifact could be placed in a Be tube or other structure relevant to target assemblies. The assembled artifact will contain many features that could be measured using various NDE methods. Some of these features are: Diameter; Maximum height; Step height; Dimensions of upper step; Radius at the union of the bottom of step and the vertical wall; Sizes of the grooves; Distance from step to groove; Slot width; Slot height; Location of the groove beneath the tracer; Diameter and location of drilled hole in tracer; and Size and location of slot in tracer. The spherical reference artifact is illustrated in Figure 2. This artifact is intended to replicate a double shell target, which consists of concentric polymer spheres separated by aerogel. The artifact consists of an upper hemispherical shell composed of 1% BrCH, which mates via a step joint with a hemispherical component made of polystyrene. This lower component

  5. The Rorschach Perceptual-Thinking Index (PTI): An Examination of Reliability, Validity, and Diagnostic Efficiency

    ERIC Educational Resources Information Center

    Hilsenroth, Mark J.; Eudell-Simmons, Erin M.; DeFife, Jared A.; Charnas, Jocelyn W.

    2007-01-01

    This study investigates the reliability, validity, and diagnostic efficiency of the Rorschach Perceptual-Thinking Index (PTI) in relation to the accurate identification of psychotic disorder (PTD) patients. The PTI is a revision of the Rorschach Schizophrenia Index (SCZI), designed to achieve several criteria, including an increase in the…

  6. Examining Reliability of Reading Comprehension Ratings of Fifth Grade Students' Oral Retellings

    ERIC Educational Resources Information Center

    Bernfeld, L. Elizabeth Shirley; Morrison, Timothy G.; Sudweeks, Richard R.; Wilcox, Brad

    2013-01-01

    The purpose of this study was to rate oral retellings of fifth graders to determine how passages, raters, and rating occasions affect those ratings, and to identify what combination of those elements produce reliable retelling ratings. A group of 36 fifth grade students read and orally retold three contemporary realistic fiction passages. Two…

  7. Assessing Reliability: Critical Corrections for a Critical Examination of the Rorschach Comprehensive System.

    ERIC Educational Resources Information Center

    Meyer, Gregory J.

    1997-01-01

    In reply to criticism of the Rorschach Comprehensive System (CS) by J. Wood, M. Nezworski, and W. Stejskal (1996), this article presents a meta-analysis of published data indicating that the CS has excellent chance-corrected interrater reliability. It is noted that the erroneous assumptions of Wood et al. make their assertions about validity…

  8. The Examination of Reliability According to Classical Test and Generalizability on a Job Performance Scale

    ERIC Educational Resources Information Center

    Yelboga, Atilla; Tavsancil, Ezel

    2010-01-01

    In this research, the classical test theory and generalizability theory analyses were carried out with the data obtained by a job performance scale for the years 2005 and 2006. The reliability coefficients obtained (estimated) from the classical test theory and generalizability theory analyses were compared. In classical test theory, test retest…

  9. Can We Trust Levelled Texts? An Examination of Their Reliability and Quality from a Linguistic Perspective

    ERIC Educational Resources Information Center

    Pitcher, Brandy; Fang, Zhihui

    2007-01-01

    Over the past decade in the United States, levelled texts, or "little books" with finely graduated levelling of text difficulty, have regained their status as a literacy staple for beginning readers. Despite their resurgence, questions remain regarding the reliability and quality of these books. In this study, we conducted a detailed analysis of…

  10. Relationship Skills in a Clinical Performance Examination: Reliability and Validity of the Relationship Instrument.

    ERIC Educational Resources Information Center

    Bolton, Cynthia; And Others

    Among the repertoire of clinical skills necessary for the professional development of medical students is the ability to create a positive doctor-patient relationship through effective communication skills. The purpose of this study was to create an instrument that reliably measures the relationship between physician and patient. The Relationship…

  11. Examining the Reliability and Validity of the Effective Behavior Support Self-Assessment Survey

    ERIC Educational Resources Information Center

    Solomon, Benjamin G.; Tobin, Kevin G.; Schutte, Gregory M.

    2015-01-01

    The Effective Behavior Support Self-Assessment Survey (SAS; Sugai, Horner, & Todd, 2003) is designed to measure perceived Positive Behavior Interventions and Supports (PBIS) implementation and identify priorities for improvement. Despite its longevity, little published research exists documenting its reliability or validity for these purposes.…

  12. Test Theories, Educational Priorities and Reliability of Public Examinations in England

    ERIC Educational Resources Information Center

    Baird, Jo-Anne; Black, Paul

    2013-01-01

    Much has already been written on the controversies surrounding the use of different test theories in educational assessment. Other authors have noted the prevalence of classical test theory over item response theory in practice. This Special Issue draws together articles based upon work conducted on the Reliability Programme for England's…

  13. Examining the scope of questionable diagnostic reliability in Sexually Violent Predator (SVP) evaluations.

    PubMed

    Perillo, Anthony D; Spada, Ashley H; Calkins, Cynthia; Jeglic, Elizabeth L

    2014-01-01

    Research has suggested questionable reliability of diagnosing mental abnormality during Sexually Violent Predator (SVP) evaluations, despite this being a necessary requirement for SVP commitment. Findings have been inconsistent across studies, and little is known about the extent of such trends across diagnoses and clinicians. The current study includes data from 375 sex offenders referred for evaluation for SVP commitment in New Jersey. Clinicians (n = 128) rendered a variety of diagnoses, most commonly Pedophilia. Results suggested questionable agreement across paraphilic and non-paraphilic diagnoses, although agreement was fair for diagnoses of Pedophilia. Further analyses of cases (n = 49) involving clinicians receiving a large number of referrals (n = 14) were generally consistent with these findings, with no outlier effect apparent. Findings suggest questionable diagnostic reliability to be a widespread issue in SVP evaluations, present across a variety of diagnoses and across the general body of clinicians involved in evaluations. PMID:24274914

  14. Development of the Anxiety Scale for Natural Disaster: Examination of its Reliability

    NASA Astrophysics Data System (ADS)

    Matsumoto, Miki; Yatabe, Ryuichi

    The objective of present study was to develop the a nxiety scale for natural disaster, and to examineits reliability. We developed the 14 items for the anxiety scale based on anticipated damage of Nankai earthquake in Ehime prefecture. The subjects consist of 391 people in Yawatahama city, Ehime prefecture. Firstly, we analyzed the latent factors which influenced the anxiety for natural disaster by using the factor analysis method. Secondly, we cal culated Cronbach's coefficient alpha. The result of the factor analysis confirmed the three factors such as "anxiety for lifeline damage", "anxiety for second ary disaster" and "fear for others". Cronbach's coefficient alpha for each factor showed the high interna l consistency reliability. We considered that each factor could prove to be a valuable tool for researc h about the person's anxiety for natural disaster.

  15. NASA DOE POD NDE Capabilities Data Book

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    2015-01-01

    This data book contains the Directed Design of Experiments for Validating Probability of Detection (POD) Capability of NDE Systems (DOEPOD) analyses of the nondestructive inspection data presented in the NTIAC, Nondestructive Evaluation (NDE) Capabilities Data Book, 3rd ed., NTIAC DB-97-02. DOEPOD is designed as a decision support system to validate inspection system, personnel, and protocol demonstrating 0.90 POD with 95% confidence at critical flaw sizes, a90/95. The test methodology used in DOEPOD is based on the field of statistical sequential analysis founded by Abraham Wald. Sequential analysis is a method of statistical inference whose characteristic feature is that the number of observations required by the procedure is not determined in advance of the experiment. The decision to terminate the experiment depends, at each stage, on the results of the observations previously made. A merit of the sequential method, as applied to testing statistical hypotheses, is that test procedures can be constructed which require, on average, a substantially smaller number of observations than equally reliable test procedures based on a predetermined number of observations.

  16. Advanced Eddy current NDE steam generator tubing.

    SciTech Connect

    Bakhtiari, S.

    1999-03-29

    As part of a multifaceted project on steam generator integrity funded by the U.S. Nuclear Regulatory Commission, Argonne National Laboratory is carrying out research on the reliability of nondestructive evaluation (NDE). A particular area of interest is the impact of advanced eddy current (EC) NDE technology. This paper presents an overview of work that supports this effort in the areas of numerical electromagnetic (EM) modeling, data analysis, signal processing, and visualization of EC inspection results. Finite-element modeling has been utilized to study conventional and emerging EC probe designs. This research is aimed at determining probe responses to flaw morphologies of current interest. Application of signal processing and automated data analysis algorithms has also been addressed. Efforts have focused on assessment of frequency and spatial domain filters and implementation of more effective data analysis and display methods. Data analysis studies have dealt with implementation of linear and nonlinear multivariate models to relate EC inspection parameters to steam generator tubing defect size and structural integrity. Various signal enhancement and visualization schemes are also being evaluated and will serve as integral parts of computer-aided data analysis algorithms. Results from this research will ultimately be substantiated through testing on laboratory-grown and in-service-degraded tubes.

  17. Assessing the Reliability of Ultrasound Imaging to Examine Radial Nerve Excursion.

    PubMed

    Kasehagen, Ben; Ellis, Richard; Mawston, Grant; Allen, Scott; Hing, Wayne

    2016-07-01

    Ultrasound imaging allows cost effective in vivo analysis for quantifying peripheral nerve excursion. This study used ultrasound imaging to quantify longitudinal radial nerve excursion during various active and passive wrist movements in healthy participants. Frame-by-frame cross-correlation software allowed calculation of nerve excursion from video sequences. The reliability of ultrasound measurement of longitudinal radial nerve excursion was moderate to high (intraclass correlation coefficient range = 0.63-0.86, standard error of measurement 0.19-0.48). Radial nerve excursion ranged from 0.41 to 4.03 mm induced by wrist flexion and 0.28 to 2.91 mm induced by wrist ulnar deviation. No significant difference was seen in radial nerve excursion during either wrist movement (p > 0.05). Wrist movements performed in forearm supination produced larger overall nerve excursion (1.41 ± 0.32 mm) compared with those performed in forearm pronation (1.06 ± 0.31 mm) (p < 0.01). Real-time ultrasound is a reliable, cost-effective, in vivo method for analysis of radial nerve excursion. PMID:27087692

  18. [Examination of safety improvement by failure record analysis that uses reliability engineering].

    PubMed

    Kato, Kyoichi; Sato, Hisaya; Abe, Yoshihisa; Ishimori, Yoshiyuki; Hirano, Hiroshi; Higashimura, Kyoji; Amauchi, Hiroshi; Yanakita, Takashi; Kikuchi, Kei; Nakazawa, Yasuo

    2010-08-20

    How the maintenance checks of the medical treatment system, including start of work check and the ending check, was effective for preventive maintenance and the safety improvement was verified. In this research, date on the failure of devices in multiple facilities was collected, and the data of the trouble repair record was analyzed by the technique of reliability engineering. An analysis of data on the system (8 general systems, 6 Angio systems, 11 CT systems, 8 MRI systems, 8 RI systems, and the radiation therapy system 9) used in eight hospitals was performed. The data collection period assumed nine months from April to December 2008. Seven items were analyzed. (1) Mean time between failures (MTBF) (2) Mean time to repair (MTTR) (3) Mean down time (MDT) (4) Number found by check in morning (5) Failure generation time according to modality. The classification of the breakdowns per device, the incidence, and the tendency could be understood by introducing reliability engineering. Analysis, evaluation, and feedback on the failure generation history are useful to keep downtime to a minimum and to ensure safety. PMID:20953108

  19. Inter-examiner reliability of diplomats in the mechanical diagnosis and therapy system in assessing patients with shoulder pain

    PubMed Central

    Abady, Afshin Heidar; Rosedale, Richard; Overend, Tom J; Chesworth, Bert M; Rotondi, Michael A

    2014-01-01

    Objective: To investigate the inter-examiner reliability of Mechanical Diagnosis and Therapy (MDT)-trained diplomats in classifying patients with shoulder disorders. The MDT system has demonstrated acceptable reliability when used in patients with spinal disorders; however, little is known about its utility when used for appendicular conditions. Methods: Fifty-four clinical scenarios were created by a group of 11 MDT diploma holders based on their clinical experience with patients with shoulder pain. The vignettes were made anonymous, and their clinical diagnoses sections were left blank. The vignettes were sent to a second group of six international McKenzie Institute diploma holders who were asked to classify each vignette according to the MDT categories for upper extremity. Inter-examiner agreement was evaluated with kappa statistics. Results: There was ‘very good’ agreement among the six MDT diplomats for classifying the McKenzie syndromes in patients with shoulder pain (kappa = 0.90, SE = 0.018). The raw overall level of multi-rater agreement among the six clinicians in classifying the vignettes was 96%. After accounting for the actual MDT category for each vignette, kappa and the raw overall level of agreement decreased negligibly (0.89 and 95%, respectively). Discussion: Using clinical vignettes, the McKenzie system of MDT has very good reliability in classifying patients with shoulder pain. As an alternative, future reliability studies could use real patients instead of written vignettes. PMID:25395828

  20. Test-retest reliability of the eating disorder examination-questionnaire (EDE-Q) in a college sample

    PubMed Central

    2013-01-01

    Background The Eating Disorder Examination-Questionnaire (EDE-Q), a widely used self-report instrument, is often used for measuring change in eating disorder symptoms over the course of treatment. However, limited data exist about test-retest reliability, particularly for men. The current study evaluated EDE-Q 7-day test-retest reliability in male (n = 47) and female (n = 44) undergraduate students together and separately by gender. Results Internal consistency was consistently higher for women and at Time 2, but remained acceptable for both men and women at both time points. Cronbach’s α ranged from .75 (Restraint at Time 1) to .93 (Shape Concern at Time 2) for women and from .73 (Eating Concern at Time 2) to .89 (Shape Concern at Time 2) for men. With the exception of some of the eating disorder behaviors, test re-test reliability was fairly strong for both men and women. Shape Concern and the global EDE-Q score were highest for both men and women (Spearman’s rho > 0.89 with the exception of Shape Concern for women for which Spearman’s rho = .86). Test re-test reliability was lower for the eating disorder behavior measures, particularly for men, for whom Kendall’s tau-b for frequency and phi for occurrence was less than 0.70 for all but objective bulimic episodes. Conclusions Results were consistent with past research for women, indicating strong test re-test reliability in attitudinal features of eating disorders, but lower test re-test reliability in behavioral features. Internal consistency and test re-test reliability was good for the attitudinal features of eating disorder in men, but tended to be lower for men compared to women. The EDE-Q appears to be a reliable instrument for assessing eating disorder attitudes in both male and female undergraduate students, but is less reliable for assessing ED behaviors, particularly in men. PMID:24999420

  1. Improving the Reliability of Autism Diagnoses: Examining the Utility of Adaptive Behavior

    ERIC Educational Resources Information Center

    Tomanik, Stacey S.; Pearson, Deborah A.; Loveland, Katherine A.; Lane, David M.; Shaw, J. Bryant

    2007-01-01

    The classification agreement of the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS) was examined in 129 children and adolescents (aged 7-18 years) who were evaluated for autism. Participants received a diagnosis of autism or non-autism based on the ADI-R. Linear discriminant analysis revealed…

  2. Examining Interrater Reliability and Validity of a Paediatric Cardiopulmonary Physiotherapy Discharge Tool

    PubMed Central

    Pellow, Vanessa; Sproule, Jeannine; Brooks, Dina; Ellerton, Cindy

    2014-01-01

    ABSTRACT Purpose: To determine the interrater reliability (IRR) of the individual items in the Paediatric Cardiopulmonary Physiotherapy (CPT) Discharge Tool. This tool identifies six critical items that physiotherapists should consider when determining a paediatric patient's readiness for discharge from CPT after upper-abdominal, cardiac, or thoracic surgery: oxygen saturation, mobility, secretion retention, discharge planning, auscultation, and signs of respiratory distress. Methods: A total of 33 paediatric patients (ages 2 to <19 years) who received at least 1 day of CPT following cardiac, thoracic, or upper-abdominal surgery were independently assessed using the Paediatric CPT Discharge Tool by two designated assessors, who assessed each patient within 4 hours of each other. Results: Kappa analysis showed the following levels of interrater agreement for the six items of the Paediatric CPT Discharge Tool: Oxygen Saturation, excellent (κ=0.80); Mobility, substantial (κ=0.62); Secretion Clearance, moderate (κ=0.39); Discharge Planning, fair (κ=0.37); and Auscultation and Respiratory Distress, poor (κ=0.24 and κ=−0.08, respectively). Conclusion: Several of the items in the Paediatric CPT Discharge Tool demonstrate good IRR. The discharge tool is ready for further psychometric testing, specifically validity testing. PMID:24799752

  3. Narrative Review: Should Teaching of the Respiratory Physical Examination Be Restricted Only to Signs with Proven Reliability and Validity?

    PubMed Central

    Baumal, Reuben

    2010-01-01

    OBJECTIVE To review the reported reliability (reproducibility, inter-examiner agreement) and validity (sensitivity, specificity and likelihood ratios) of respiratory physical examination (PE) signs, and suggest an approach to teaching these signs to medical students. METHODS Review of the literature. We searched Paper Chase between 1966 and June 2009 to identify and evaluate published studies on the diagnostic accuracy of respiratory PE signs. RESULTS Most studies have reported low to fair reliability and sensitivity values. However, some studies have found high specificites for selected PE signs. None of the studies that we reviewed adhered to all of the STARD criteria for reporting diagnostic accuracy. CONCLUSIONS Possible flaws in study designs may have led to underestimates of the observed diagnostic accuracy of respiratory PE signs. The reported poor reliabilities may have been due to differences in the PE skills of the participating examiners, while the sensitivities may have been confounded by variations in the severity of the diseases of the participating patients. IMPLICATION FOR PRACTICE AND MEDICAL EDUCATION Pending the results of properly controlled studies, the reported poor reliability and sensitivity of most respiratory PE signs do not necessarily detract from their clinical utility. Therefore, we believe that a meticulously performed respiratory PE, which aims to explore a diagnostic hypothesis, as opposed to a PE that aims to detect a disease in an asymptomatic person, remains a cornerstone of clinical practice. We propose teaching the respiratory PE signs according to their importance, beginning with signs of life-threatening conditions and those that have been reported to have a high specificity, and ending with signs that are "nice to know," but are no longer employed because of the availability of more easily performed tests. PMID:20349154

  4. NEW NONLINEAR ACOUSTIC TECHNIQUES FOR NDE

    SciTech Connect

    J. A. TENCATE

    2000-09-01

    Acoustic nonlinearity in a medium may occur as a result of a variety of mechanisms. Some of the more common nonlinear effects may come from: (1) one or several cracks, volumetrically distributed due to age or fatigue or single disbonds or delamination; (2) imperfect grain-to-grain contacts, e.g., materials like concretes that are cemented together and have less than perfect bonds; (3) hard parts in a soft matrix, e.g., extreme duty materials like tungsten/copper alloys; or (4) atomic-scale nonlinearities. Nonlinear effects that arise from the first two mechanisms are considerably larger than the last two; thus, we have focused considerable attention on these. The most pervasive nonlinear measure of damage today is a second harmonic measurement. We show that for many cases of interest to NDE, a second harmonic measurement may not be the best choice. We examine the manifestations of nonlinearity in (nonlinear) materials with cracks and/or imperfect bonds and illustrate their applicability to NDE. For example, nonlinear resonance frequency shifts measured at increasing drive levels correlate strongly with the amount of ASR (alkali-silica reaction) damage of concrete cores. Memory effects (slow dynamics) also seem to correlate with the amount of damage.

  5. Terahertz NDE for Under Paint Corrosion Detection and Evaluation

    NASA Technical Reports Server (NTRS)

    Anastasi, Robert F.; Madaras, Eric I.

    2005-01-01

    Corrosion under paint is not visible until it has caused paint to blister, crack, or chip. If corrosion is allowed to continue then structural problems may develop. Identifying corrosion before it becomes visible would minimize repairs and costs and potential structural problems. Terahertz NDE imaging under paint for corrosion is being examined as a method to inspect for corrosion by examining the terahertz response to paint thickness and to surface roughness.

  6. Challenges of NDE Simulation Tool Challenges of NDE Simulation Tool

    NASA Technical Reports Server (NTRS)

    Leckey, Cara A. C.; Juarez, Peter D.; Seebo, Jeffrey P.; Frank, Ashley L.

    2015-01-01

    Realistic nondestructive evaluation (NDE) simulation tools enable inspection optimization and predictions of inspectability for new aerospace materials and designs. NDE simulation tools may someday aid in the design and certification of advanced aerospace components; potentially shortening the time from material development to implementation by industry and government. Furthermore, modeling and simulation are expected to play a significant future role in validating the capabilities and limitations of guided wave based structural health monitoring (SHM) systems. The current state-of-the-art in ultrasonic NDE/SHM simulation cannot rapidly simulate damage detection techniques for large scale, complex geometry composite components/vehicles with realistic damage types. This paper discusses some of the challenges of model development and validation for composites, such as the level of realism and scale of simulation needed for NASA' applications. Ongoing model development work is described along with examples of model validation studies. The paper will also discuss examples of the use of simulation tools at NASA to develop new damage characterization methods, and associated challenges of validating those methods.

  7. Through the looking glass: The future for NDE?

    NASA Astrophysics Data System (ADS)

    Bond, Leonard J.

    2014-02-01

    Nondestructive testing (NDT) is a mature industry, with global equipment sales fast moving towards 2B. per year. The use of conventional NDT will grow in developing countries and in developed countries the challenges will include those associated with maintaining aging infrastructure. For some systems the future will move to structural health monitoring (SHM) and for others into integration of online measurements in manufacturing. Nondestructive Evaluation (NDE) is a multi-disciplinary area of endeavor that has its origins in materials science and NDT. It seeks to provide an adequate science base for NDT to become a quantitative science. It was seen to be necessary to better detect, size and type defects, improve the reliability of inspection, and probability of detection (POD). There is particular interest in estimating the potential defects could have on performance or potential for loss of structural integrity, under various loading or stressor conditions, and ultimately implement risk-based reliability assessments. NDE must be seen more as a part of the wide field of engineering, as an interdisciplinary endeavor, that brings together the expertise of materials science and metrology, together with the underlying physics for inspection methods, as well as statistics, computers, robotics and software. The adoption of advanced manufacturing, will require new metrology tools and methods to provide data for assessing new materials including powder metals, as used in additive manufacturing, and various composites. The lessons from the past proceedings of this conference series include that the problems faced today are harder than was expected during the first decade of quantitative NDE research. Even with new types of transducers and much improved A/D and powerful computers new approaches and more basic measurement physics being understood, new insights are needed to provide the data needed to solve many real-world NDE problems, to understand and measure early

  8. Learning objectives for NDE education

    NASA Astrophysics Data System (ADS)

    Thompson, R. B.

    2001-04-01

    A brainstorming session regarding learning objectives or desired outcomes for NDE education, held on Thursday afternoon, July 20, 2000 at the Review of Progress in Quantitative Nondestructive Evaluation, is discussed. Primary attention is paid to undergraduate education with some discussion of graduate education. The proposed learning objectives are first presented, as formulated by an international group of NDE educators representing the World Federation of NDE Centers. This is followed by a summary of the discussions of those objectives by a group of educators, industrialists and government employees who participated in the brainstorming session. Viewpoints were wide ranging and a unanimous consensus position was not reached in all cases. Nevertheless, some important trends emerged in the discussions and a number of issues were framed more clearly than in the past. These are documented to provide a basis of continued discussions in the future. Generally speaking, the proposed learning objectives were believed to be appropriate but further discussion is required to define the appropriate title to associate with an individual who has achieved those objectives.

  9. Terahertz NDE Application for Corrosion Detection and Evaluation under Shuttle Tiles

    NASA Technical Reports Server (NTRS)

    Anastasi, Robert F.; Madaras, Eric I.; Seebo, Jeffrey P.; Smith, Stephen W.; Lomness, Janice K.; Hintze, Paul E.; Kammerer, Catherine C.; Winfree, William P.; Russell, Richard W.

    2007-01-01

    Pulsed Terahertz NDE is being examined as a method to inspect for possible corrosion under Space Shuttle Tiles. Other methods such as ultrasonics, infrared, eddy current and microwave technologies have demonstrable shortcomings for tile NDE. This work applies Terahertz NDE, in the frequency range between 50 GHz and 1 THz, for the inspection of manufactured corrosion samples. The samples consist of induced corrosion spots that range in diameter (2.54 to 15.2 mm) and depth (0.036 to 0.787 mm) in an aluminum substrate material covered with tiles. Results of these measurements are presented for known corrosion flaws both covered and uncovered and for blind tests with unknown corrosion flaws covered with attached tiles. The Terahertz NDE system is shown to detect all artificially manufactured corrosion regions under a Shuttle tile with a depth greater than 0.13 mm.

  10. Application of damage mechanism-specific NDE methods in support of risk-informed inspections

    SciTech Connect

    Walker, S.M.; Ammirato, F.V.

    1996-12-01

    Risk-informed inservice inspection (RISI) programs effectively concentrate limited and costly examination resources on systems and locations most relevant to plant safety. The thought process used in the selection of nondestructive evaluation (NDE) methods and procedures in a RISI program is expected to change toward integrating NDE into integrity management, with a concentration on understanding failure mechanisms. Identifying which damage mechanisms may be operative in specific locations and applying appropriate NDE methods to detect the presence of these damage mechanisms is fundamental to effective RISI application. Considerable information is already available on inspection for damage mechanisms such as intergranular stress corrosion cracking (IGSCC), thermal fatigue, and erosion-corrosion. Similar procedures are under development for other damage mechanisms that may occur individually or in combination with other mechanisms. Guidance is provided on application of NDE procedures in an RISI framework to facilitate implementation by utility staff (Gosselin, 1996).

  11. Fixed Eigenvector Analysis of Thermographic NDE Data

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott; Winfree, William P.

    2011-01-01

    Principal Component Analysis (PCA) has been shown effective for reducing thermographic NDE data. This paper will discuss an alternative method of analysis that has been developed where a predetermined set of eigenvectors is used to process the thermal data from both reinforced carbon-carbon (RCC) and graphiteepoxy honeycomb materials. These eigenvectors can be generated either from an analytic model of the thermal response of the material system under examination, or from a large set of experimental data. This paper provides the details of the analytic model, an overview of the PCA process, as well as a quantitative signal-to-noise comparison of the results of performing both conventional PCA and fixed eigenvector analysis on thermographic data from two specimens, one Reinforced Carbon-Carbon with flat bottom holes and the second a sandwich construction with graphite-epoxy face sheets and aluminum honeycomb core.

  12. The reliability of the examination of foods, processed for safety, for enteric pathogens and Enterobacteriaceae: a mathematical and ecological study

    PubMed Central

    Drion, E. F.; Mossel, D. A. A.

    1977-01-01

    Because of the paucity of quantitative data on numbers of other enteric pathogens in food, the reliability of the examination of processed foods for Enterobacteriaceae was estimated taking Salmonella as a model. For this purpose an assessment was carried out of the risk of accepting Salmonella contaminated consignments of foods, despite a negative outcome of (i) examination of 1·5 kg samples for Salmonella; (ii) examination of one or two 1 g samples for Enterobacteriaceae; (iii) simultaneous application of both tests. The computations were based on the results of the examination of 6830 samples of dried foods, processed for safety, out of a total of 18170 samples. Only 69 samples permitted the exact calculation of the ε-factor, defined as c.f.u./g of Enterobacteriaceae/c.f.u./g of Salmonella; 4642 were positive for the former group but `free' from Salmonella, and the rest were negative in both tests. Numbers of c.f.u./g for both groups, and hence the ε-factors, varied widely between commodities and also between different consignments of the same food product. The average for ε amounted to 5·8 × 103, far from the base-line value of 0·75 × 103 assessed earlier. In only 0·1% of samples did the Enterobacteriaceae test fail to achieve the required consumer protection. This investigation therefore substantiates that testing foods processed for safety by examining accurately chosen quantities for ecologically well selected and taxonomically thoroughly defined index organisms is a most effective procedure in terms both of consumer protection and simplicity of examination without compelling the food industry to achieve hardly attainable microbiological quality standards. PMID:325125

  13. Orbiter Cold Plate Intergranular Corrosion: Development of NDE Standards and Assessment of NDE Methods

    NASA Technical Reports Server (NTRS)

    Smith, Stephen W.; Winfree, William P.; Piascik, Robert S.

    2002-01-01

    During pre-servicing of a space shuttle (orbiter vehicle, OV-102), helium leak detection of an avionics cold plate identified a leak located in the face sheet oriented towards the support shelf. Subsequent destructive examination of the leaking cold plate revealed that intergranular corrosion had penetrated the 0.017-inch thick aluminum (AA6061) face sheet. The intergranular attack (IGA) was likely caused by an aggressive crevice environment created by condensation of water vapor between the cold plate and support shelf. Face sheet susceptibility to IGA is a result of the brazing process used in the fabrication of the cold plates. Cold plate components were brazed at 1000 F followed by a slow cooling process to avoid distortion of the bonded cold plate. The slow cool process caused excessive grain boundary precipitation resulting in a material that is susceptible to IGA. The objectives of this work are as follows: (1) Develop first-of-a-kind nondestructive evaluation (NDE) standards that contain IGA identical to that found in the orbiter cold plates; and (2) Assess advanced NDE techniques for corrosion detection and recommend methods for cold plate examination. This report documents the results of work performed at Langley Research Center to fulfill these objectives.

  14. Finite element analysis simulations for ultrasonic array NDE inspections

    NASA Astrophysics Data System (ADS)

    Dobson, Jeff; Tweedie, Andrew; Harvey, Gerald; O'Leary, Richard; Mulholland, Anthony; Tant, Katherine; Gachagan, Anthony

    2016-02-01

    Advances in manufacturing techniques and materials have led to an increase in the demand for reliable and robust inspection techniques to maintain safety critical features. The application of modelling methods to develop and evaluate inspections is becoming an essential tool for the NDE community. Current analytical methods are inadequate for simulation of arbitrary components and heterogeneous materials, such as anisotropic welds or composite structures. Finite element analysis software (FEA), such as PZFlex, can provide the ability to simulate the inspection of these arrangements, providing the ability to economically prototype and evaluate improved NDE methods. FEA is often seen as computationally expensive for ultrasound problems however, advances in computing power have made it a more viable tool. This paper aims to illustrate the capability of appropriate FEA to produce accurate simulations of ultrasonic array inspections - minimizing the requirement for expensive test-piece fabrication. Validation is afforded via corroboration of the FE derived and experimentally generated data sets for a test-block comprising 1D and 2D defects. The modelling approach is extended to consider the more troublesome aspects of heterogeneous materials where defect dimensions can be of the same length scale as the grain structure. The model is used to facilitate the implementation of new ultrasonic array inspection methods for such materials. This is exemplified by considering the simulation of ultrasonic NDE in a weld structure in order to assess new approaches to imaging such structures.

  15. NDE Activity at Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Y.

    1993-01-01

    None, This is a viewgraph outline from an oral presentation. From Intro.: Our speaker will review the NDE technology under development at the Jet Propulsion Laboratory (JPL). Emphasis will be given to Ultrasonics and application of sensors to space technology. Further, the efforts of JPL in technology transfer to the industry in the area of NDE will be covered.

  16. NDE Methodologies for Composite Flywheels Certification

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  17. Microwave NDE for Reinforced Concrete

    NASA Astrophysics Data System (ADS)

    Arunachalam, Kavitha; Melapudi, Vikram R.; Rothwell, Edward J.; Udpa, Lalita; Udpa, Satish S.

    2006-03-01

    Nondestructive assessment of the integrity of civil structures is of paramount importance for ensuring safety. In concrete imaging, radiography, ground penetrating radar and infrared thermography are some of the widely used techniques for health monitoring. Other emerging technologies that are gaining impetus for detecting and locating flaws in steel reinforcement bar include radioactive computed tomography, microwave holography, microwave and acoustic tomography. Of all the emerging techniques, microwave NDT is a promising imaging modality largely due to their ability to penetrate thick concrete structures, contrast between steel rebar and concrete and their non-radioactive nature. This paper investigates the feasibility of a far field microwave NDE technique for reinforced concrete structures.

  18. The point-to-point test: A new diagnostic tool for measuring lumbar tactile acuity? Inter and intra-examiner reliability study of pain-free subjects.

    PubMed

    Adamczyk, Wacław; Sługocka, Anna; Saulicz, Oskar; Saulicz, Edward

    2016-04-01

    A two-point discrimination test (TPD) is commonly used to investigate lumbar tactile acuity. However, low inter-examiner reliability and difficulties in execution significantly limit its application. Therefore the aim of this study was to compare the inter- and intra-examiner reliability of a new approach, the point-to-point test (PTP), with the TPD. Twenty-one pain-free subjects attended the inter-examiner stage of the study. Eighteen of them were further recruited into an intra-examiner (reproducibility and repeatability) reliability study. PTP was performed on the three points plotted at the L3 spinal level. Point '0' overlapped with the L3 spinous process, from which points '1' and '2' were horizontally separated by 5 and 10 cm, respectively. Participants manually indicated a point previously touched by the examiner, while the distance (error) was measured. Reliability was determined with the intraclass correlation coefficient (ICC2,3). The results revealed good and moderate inter- and intra-examiner reliability at point '1' (ICC2,3 = 0.68-0.84) and good reliability at point '2' (ICC2,3 = 0.84-0.86). At point '0', reliability was moderate to poor (ICC2,3 = 0.13-0.63). TPD was characterised by a poor to moderate level of inter- (ICC2,1 = 0.51; ICC2,3 = 0.56) and intra-examiner reliability (ICC(2,1) = 0.50; ICC2,3 = 0.74). Our findings suggest that PTP is more reliable than TPD at two investigated points at the L3 spinal level. However, further research on PTP validity data is strongly warranted. PMID:26797175

  19. NDE of titanium alloy MMC rings for gas turbine engines

    NASA Technical Reports Server (NTRS)

    Baaklini, George Y.; Percival, Larry D.; Yancey, Robert N.; Kautz, Harold E.

    1993-01-01

    Progress in the processing and fabrication of metal matrix composites (MMC's) requires appropriate mechanical and nondestructive testing methods. These methods are needed to characterize properties, assess integrity, and predict the life of engine components such as compressor rotors, blades, and vanes. Capabilities and limitations of several state-of-the-art nondestructive evaluation (NDE) technologies are investigated for characterizing titanium MMC rings for gas turbine engines. The use of NDE technologies such as x-ray computed tomography, radiography, and ultrasonics in identifying fabrication-related problems that caused defects in components is examined. Acousto-ultrasonics was explored to assess degradation of material mechanical properties by using stress wave factor and ultrasonic velocity measurements before and after the burst testing of the rings.

  20. NDE of PWA 1480 single crystal turbine blade material

    NASA Technical Reports Server (NTRS)

    Klima, Stanley J.; Orange, Thomas W.; Dreshfield, Robert L.

    1993-01-01

    Cantilever bending fatigue specimens were examined by fluorescent liquid penetrant and radioactive gas penetrant (Krypton) Nondestructive Evaluation (NDE) methods and tested. Specimens with cast, ground, or polished surfaces were evaluated to study the effect of surface condition on NDE and fatigue crack initiation. Fractographic and metallurgical analyses were performed to determine the nature of crack precursors. Preliminary results show that fatigue strength was lower for specimens with cast surfaces than for specimens with machined surfaces. The liquid penetrant and gas penetrant techniques both provided indications of a large population of defects on the cast surfaces. On ground or polished specimen surfaces, the gas penetrant appeared to estimate the actual number of voids more accurately than the liquid penetrant.

  1. NDE of PWA 1480 single crystal turbine blade material

    NASA Technical Reports Server (NTRS)

    Klima, Stanley J.; Orange, Thomas W.; Dreshfield, Robert L.

    1993-01-01

    Cantilever bending fatigue specimens were examined by fluorescent liquid penetrant and radioactive gas penetrant (Krypton) non-destructive evaluation (NDE) methods and tested. Specimens with cast, ground, or polished surface were evaluated to study the effect of surface condition on NDE and fatigue crack initiation. Fractographic and metallurgical analyses were performed to determine the nature of crack precursors. Preliminary results show that fatigue strength was lower for specimens with cast surfaces than for specimens with machined surfaces. The liquid penetrant and gas penetrant techniques both provided indications of a large population of defects on the cast surfaces. On ground or polished specimen surfaces, the gas penetrant appeared to estimate the actual number of voids more accurately than the liquid penetrant.

  2. Developing NDE Techniques for Large Cryogenic Tanks

    NASA Technical Reports Server (NTRS)

    Parker, Don; Starr, Stan

    2009-01-01

    The Shuttle and Constellation Programs require very large cryogenic ground storage tanks in which to store liquid oxygen and hydrogen. The existing LC-39 pad tanks, which will be passed onto Constellation, are 40 years old and have received minimal refurbishment or even inspection, because they can only be temperature cycled a few times before being overhauled (a costly operation in both time and dollars). Numerous questions exist on the performance and reliability of these old tanks which could cause a major Program schedule disruption. Consequently, with the passing of the first two tanks to Constellation to occur this year, there is growing awareness that NDE is needed to detect problems early in these tanks so that corrective actions can be scheduled when least disruptive. Time series thermal images of two sides of the Pad B LH2 tank have been taken over multiple days to demonstrate the effects of environmental conditions to the solar heating of the tank and therefore the effectiveness of thermal imaging.

  3. Simple Syringe Filtration Methods for Reliably Examining Dissolved and Colloidal Trace Element Distributions in Remote Field Locations

    NASA Astrophysics Data System (ADS)

    Shiller, A. M.

    2002-12-01

    Methods for obtaining reliable dissolved trace element samples frequently utilize clean labs, portable laminar flow benches, or other equipment not readily transportable to remote locations. In some cases unfiltered samples can be obtained in a remote location and transported back to a lab for filtration. However, this may not always be possible or desirable. Additionally, methods for obtaining information on colloidal composition are likewise frequently too cumbersome for remote locations as well as being time-consuming. For that reason I have examined clean methods for collecting samples filtered through 0.45 and 0.02 micron syringe filters. With this methodology, only small samples are collected (typically 15 mL). However, with the introduction of the latest generation of ICP-MS's and microflow nebulizers, sample requirements for elemental analysis are much lower than just a few years ago. Thus, a determination of a suite of first row transition elements is frequently readily obtainable with samples of less than 1 mL. To examine the "traditional" (<0.45 micron) dissolved phase, 25 mm diameter polypropylene syringe filters and all polyethylene/polypropylene syringes are utilized. Filters are pre-cleaned in the lab using 40 mL of approx. 1 M HCl followed by a clean water rinse. Syringes are pre-cleaned by leaching with hot 1 M HCl followed by a clean water rinse. Sample kits are packed in polyethylene bags for transport to the field. Results are similar to results obtained using 0.4 micron polycarbonate screen filters, though concentrations may differ somewhat depending on the extent of sample pre-rinsing of the filter. Using this method, a multi-year time series of dissolved metals in a remote Rocky Mountain stream has been obtained. To examine the effect of colloidal material on dissolved metal concentrations, 0.02 micron alumina syringe filters have been utilized. Other workers have previously used these filters for examining colloidal Fe distributions in lake

  4. An Examination of Temporal Trends in Electricity Reliability Based on Reports from U.S. Electric Utilities

    SciTech Connect

    Eto, Joseph H.; LaCommare, Kristina Hamachi; Larsen, Peter; Todd, Annika; Fisher, Emily

    2012-01-06

    Since the 1960s, the U.S. electric power system has experienced a major blackout about once every 10 years. Each has been a vivid reminder of the importance society places on the continuous availability of electricity and has led to calls for changes to enhance reliability. At the root of these calls are judgments about what reliability is worth and how much should be paid to ensure it. In principle, comprehensive information on the actual reliability of the electric power system and on how proposed changes would affect reliability ought to help inform these judgments. Yet, comprehensive, national-scale information on the reliability of the U.S. electric power system is lacking. This report helps to address this information gap by assessing trends in U.S. electricity reliability based on information reported by electric utilities on power interruptions experienced by their customers. Our research augments prior investigations, which focused only on power interruptions originating in the bulk power system, by considering interruptions originating both from the bulk power system and from within local distribution systems. Our research also accounts for differences among utility reliability reporting practices by employing statistical techniques that remove the influence of these differences on the trends that we identify. The research analyzes up to 10 years of electricity reliability information collected from 155 U.S. electric utilities, which together account for roughly 50% of total U.S. electricity sales. The questions analyzed include: 1. Are there trends in reported electricity reliability over time? 2. How are trends in reported electricity reliability affected by the installation or upgrade of an automated outage management system? 3. How are trends in reported electricity reliability affected by the use of IEEE Standard 1366-2003?

  5. Reliability and Validity of the SE-HEPA: Examining Physical Activity- and Healthy Eating-Specific Self-Efficacy among a Sample of Preadolescents

    ERIC Educational Resources Information Center

    Steele, Michael M.; Burns, Leonard G.; Whitaker, Brandi N.

    2013-01-01

    Objective. The purpose of this study was to examine the psychometric properties of the self-efficacy for healthy eating and physical activity measure (SE-HEPA) for preadolescents. Method. The reliability of the measure was examined to determine if the internal consistency of the measure was adequate (i.e., [alpha]s greater than 0.70). Next, in an…

  6. Assessment of NDE for key indicators of aging cables in nuclear power plants - Interim status

    NASA Astrophysics Data System (ADS)

    Glass, S. W.; Ramuhalli, P.; Fifield, L. S.; Prowant, M. S.; Dib, G.; Tedeschi, J. R.; Suter, J. D.; Jones, A. M.; Good, M. S.; Pardini, A. F.; Hartman, T. S.

    2016-02-01

    Degradation of the cable jacket, electrical insulation, and other cable components of installed cables within nuclear power plants (NPPs) is known to occur as a function of age, temperature, radiation, and other environmental factors. System tests verify cable function under normal loads; however, the concern is over cable performance under exceptional loads associated with design-basis events (DBEs). The cable's ability to perform safely over the initial 40-year planned and licensed life has generally been demonstrated and there have been very few age-related cable failures. With greater than 1000 km of power, control, instrumentation, and other cables typically found in an NPP, replacing all the cables would be a severe cost burden. Justification for life extension to 60 and 80 years requires a cable aging management program to justify cable performance under normal operation as well as accident conditions. Currently the gold standard for determining cable insulation degradation is the elongation-at-break (EAB). This, however, is an ex-situ measurement and requires removal of a sample for laboratory investigation. A reliable nondestructive examination (NDE) in-situ approach is desirable to objectively determine the suitability of the cable for service. A variety of tests are available to assess various aspects of electrical and mechanical cable performance, but none of these tests are suitable for all cable configurations nor does any single test confirm all features of interest. Nevertheless, the complete collection of test possibilities offers a powerful range of tools to assure the integrity of critical cables. Licensees and regulators have settled on a practical program to justify continued operation based on condition monitoring of a lead sample set of cables where test data is tracked in a database and the required test data are continually adjusted based on plant and fleet-wide experience. As part of the Light Water Reactor Sustainability program sponsored

  7. Test-retest reliability of an active range of motion test for the shoulder and hip joints by unskilled examiners using a manual goniometer

    PubMed Central

    Kim, Seong-Gil; Kim, Eun-Kyung

    2016-01-01

    [Purpose] The purpose of this study was to analyze test-retest reliability of an active range of motion test using a manual goniometer by unskilled examiners. [Subjects and Methods] Active range of motion was measured in 30 students attending U university (4 males, 26 females). Range of motion during flexion and extension of the shoulder and hip joints were measured using a manual goniometer. [Results] Flexion and extension of the shoulder joint (ICC=0.906 and ICC=0.808) and (ICC=0.946 and ICC=0. 955) of the hip joint showed excellent reliabilities. [Conclusion] The active range of motion test using a manual goniometer showed very high test-retest reliability in unskilled examiners. When examiners are aware of the method of the test, an objective assessment can be conducted. PMID:27134347

  8. Micro- and nano-NDE systems for aircraft: great things in small packages

    NASA Astrophysics Data System (ADS)

    Malas, James C.; Kropas-Hughes, Claudia V.; Blackshire, James L.; Moran, Thomas; Peeler, Deborah; Frazier, W. G.; Parker, Danny

    2003-07-01

    Recent advancements in small, microscopic NDE sensor technologies will revolutionize how aircraft maintenance is done, and will significantly improve the reliability and airworthiness of current and future aircraft systems. A variety of micro/nano systems and concepts are being developed that will enable whole new capabilities for detecting and tracking structural integrity damage. For aging aircraft systems, the impact of micro-NDE sensor technologies will be felt immediately, with dramatic reductions in labor for maintenance, and extended useable life of critical components being two of the primary benefits. For the fleet management of future aircraft systems, a comprehensive evaluation and tracking of vehicle health throughout its entire life cycle will be needed. Indeed, micro/nano NDE systems will be instrumental in realizing this futuristic vision. Several major challenges will need to be addressed, however, before micro- and nano-NDE systems can effectively be implemented, and this will require interdisciplinary research approaches, and a systematic engineering integration of the new technologies into real systems. Future research will need to emphasize systems engineering approaches for designing materials and structures with in-situ inspection and prognostic capabilities. Recent advances in 1) embedded / add-on micro-sensors, 2) computer modeling of nondestructive evaluation responses, and 3) wireless communications are important steps toward this goal, and will ultimately provide previously unimagined opportunities for realizing whole new integrated vehicle health monitoring capabilities. The future use of micro/nano NDE technologies as vehicle health monitoring tools will have profound implications, and will provide a revolutionary way of doing NDE in the near and distant future.

  9. Characterization of melt-infiltrated SiC/SiC composite combustor liners using meso- and micro-NDE techniques

    SciTech Connect

    Ellingson, W. A.; Sun, J. G.; More, K. L.; Hines, R.

    2000-01-26

    Melt-infiltrated ceramic matrix composite SiC/SiC material systems are under development for use in combustor liners for low-emission advanced gas turbines. Uncertainty in repeatability of processing methods for these large components (33--76 cm diameter), and hence possible reduced reliability for the end user. This requires that appropriate test methods, at both meso- and micro-scale, be used to ensure that the liners are acceptable for use. Nondestructive evaluation (NDE) methods, if demonstrated to reliably detect changes caused by processing, would be of significant benefit to both manufacturer and end user. This paper describes the NDE methods and their applications in detecting a process upset in a melt-infiltrated 33 cm combustor liner and how high-resolution scanning electron microscopy was used to verify the NDE data.

  10. An Examination of Coach and Player Relationships According to the Adapted LMX 7 Scale: A Validity and Reliability Study

    ERIC Educational Resources Information Center

    Caliskan, Gokhan

    2015-01-01

    The current study aims to test the reliability and validity of the Leader-Member Exchange (LMX 7) scale with regard to coach--player relationships in sports settings. A total of 330 professional soccer players from the Turkish Super League as well as from the First and Second Leagues participated in this study. Factor analyses were performed to…

  11. Examining the Reliability of Scores from the Consensual Assessment Technique in the Measurement of Individual and Small Group Creativity

    ERIC Educational Resources Information Center

    Stefanic, Nicholas; Randles, Clint

    2015-01-01

    The purpose of this study was to explore the reliability of measures of both individual and group creative work using the consensual assessment technique (CAT). CAT was used to measure individual and group creativity among a population of pre-service music teachers enrolled in a secondary general music class (n = 23) and was evaluated from…

  12. Recent developments in SQUID NDE

    NASA Astrophysics Data System (ADS)

    Krause, H.-J.; Kreutzbruck, M. v.

    2002-03-01

    By presenting brief summaries of recent application highlights, an overview of NDE methods using SQUIDs is given. Bridge inspection with a SQUID array integrated with a yoke magnet excitation was shown by scanning along the pre-stressed steel of bridges and verified by opening the bridge deck. As the construction of the megaliner Airbus aircraft progresses, testing procedures for extremely thick-walled structures are needed. Defects at a depth of up to 40 mm were measured in a bolted three-layer aluminum sample with a total thickness of 62 mm. For the investigation of aircraft wheels, a remote eddy current (EC) excitation scheme yields better depth selectivity. Defects with an inside penetration of only 10% could be detected. SQUID magnetometers are well suited for pulsed EC techniques which cover a broader depth range than standard single frequency EC. An inversion procedure is presented providing a tomographic-like conductivity image of stacked aluminum samples. A recent SQUID application is nondestructive testing of niobium sheets used for superconducting cavities of particle accelerators. The detection of tantalum inclusions and other impurities which lower the cavity performance is based on the measurement of local current inhomogeneities caused by EC excitation or thermal gradients. Alternate techniques using SQUID sensors, such as modulated excitation arrays, rotating field schemes, sensor multiplexing, magnetic moment detection, and microscopy setups, are discussed.

  13. An NDE approach for characterizing quality problems in polymer matrix composites

    NASA Technical Reports Server (NTRS)

    Roth, Don J.; Baaklini, George Y.; Sutter, James K.; Bodis, James R.; Leonhardt, Todd A.; Crane, Elizabeth A.

    1994-01-01

    Polymer matrix composite (PMC) materials are periodically identified appearing optically uniform but containing a higher than normal level of global nonuniformity as indicated from preliminary ultrasonic scanning. One such panel was thoroughly examined by nondestructive (NDE) and destructive methods to quantitatively characterize the nonuniformity. The NDE analysis of the panel was complicated by the fact that the panel was not uniformly thick. Mapping of ultrasonic velocity across a region of the panel in conjunction with an error analysis was necessary to (1) characterize properly the porosity gradient that was discovered during destructive analyses and (2) account for the thickness variation effects. Based on this study, a plan for future NDE characterization of PMC's is presented to the PMC community.

  14. Complimentary single technique and multi-physics modeling tools for NDE challenges

    NASA Astrophysics Data System (ADS)

    Le Lostec, Nechtan; Budyn, Nicolas; Sartre, Bernard; Glass, S. W.

    2014-02-01

    The challenges of modeling and simulation for Non Destructive Examination (NDE) research and development at AREVA NDE Solutions Technical Center (NETEC) are presented. In particular, the choice of a relevant software suite covering different applications and techniques and the process/scripting tools required for simulation and modeling are discussed. The software portfolio currently in use is then presented along with the limitations of the different software: CIVA for ultrasound (UT) methods, PZFlex for UT probes, Flux for eddy current (ET) probes and methods, plus Abaqus for multiphysics modeling. The finite element code, Abaqus is also considered as the future direction for many of our NDE modeling and simulation tasks. Some application examples are given on modeling of a piezoelectric acoustic phased array transducer and preliminary thermography configurations.

  15. NDE of Fiber Reinforced Foam Composite Structures for Future Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Walker, james; Roth, Don; Hopkins, Dale

    2010-01-01

    This slide presentation reviews the complexities of non-destructive evaluation (NDE) of fiber reinforced foam composite structures to be used for aerospace vehicles in the future.Various views of fiber reinforced foam materials are shown and described. Conventional methods of NDE for composites are reviewed such as Micro-computed X-Ray Tomography, Thermography, Shearography, and Phased Array Ultrasonics (PAUT). These meth0ods appear to work well on the face sheet and face sheet ot core bond, they do not provide adequate coverage for the webs. There is a need for additional methods that will examine the webs and web to foam core bond.

  16. What Are You Measuring? Dimensionality and Reliability Analysis of Ability and Speed in Medical School Didactic Examinations.

    PubMed

    Thompson, James J

    2016-01-01

    Summative didactic evaluation often involves multiple choice questions which are then aggregated into exam scores, course scores, and cumulative grade point averages. To be valid, each of these levels should have some relationship to the topic tested (dimensionality) and be sufficiently reproducible between persons (reliability) to justify student ranking. Evaluation of dimensionality is difficult and is complicated by the classic observation that didactic performance involves a generalized component (g) in addition to subtest specific factors. In this work, 183 students were analyzed over two academic years in 13 courses with 44 exams and 3352 questions for both accuracy and speed. Reliability at all levels was good (>0.95). Assessed by bifactor analysis, g effects dominated most levels resulting in essential unidimensionality. Effect sizes on predicted accuracy and speed due to nesting in exams and courses was small. There was little relationship between person ability and person speed. Thus, the hierarchical grading system appears warrented because of its g-dependence. PMID:26784380

  17. An examination of maintenance activities in liquid metal reactor facilities: An analysis by the Centralized Reliability Data Organization (CREDO)

    SciTech Connect

    Haire, M J; Knee, H E; Manning, J J; Manneschmidt, J F; Setoguchi, K

    1987-01-01

    The Centralized Reliability Data Organization (CREDO) is the largest repository of liquid metal reactor (LMR) component reliability data in the world. It is jointly sponsored by the US Department of Energy (DOE) and the Power Reactor and Nuclear fuel Development Corporation (PNC) of Japan. The CREDO database contains information on a population of more than 21,000 components and approximately 1300 event records. Total experience is approaching 1.2 billion component operating hours. Although data gathering for CREDO concentrates on event (failure) information, the work reported here focuses on the maintenance information contained in CREDO and the development of maintenance critical items lists. That is, components are ranked in prioritized lists from worse to best performers from a maintenance standpoint.

  18. Review of progress in quantitative NDE

    SciTech Connect

    Not Available

    1992-01-01

    Abstracts of 386 papers and plenary presentations are included. The plenary sessions related to the national technology initiative. The other sessions covered the following NDE topics: corrosion, electromagnetic arrays, elastic wave scattering and backscattering/noise, civil structures, material properties, holography, shearography, UT wave propagation, eddy currents, coatings, signal processing, radiography, computed tomography, EM imaging, adhesive bonds, NMR, laser ultrasonics, composites, thermal, magnetic measurements, nonlinear acoustics, interface modeling and characterization, UT transducers, new techniques, joined materials, probes and systems, fatigue cracks and fracture, imaging and sizing, NDE in engineering and process control, acoustics of cracks, and sensors. An author index is included. (DLC)

  19. Review of progress in quantitative NDE. Abstracts

    SciTech Connect

    Not Available

    1992-09-01

    Abstracts of 386 papers and plenary presentations are included. The plenary sessions related to the national technology initiative. The other sessions covered the following NDE topics: corrosion, electromagnetic arrays, elastic wave scattering and backscattering/noise, civil structures, material properties, holography, shearography, UT wave propagation, eddy currents, coatings, signal processing, radiography, computed tomography, EM imaging, adhesive bonds, NMR, laser ultrasonics, composites, thermal, magnetic measurements, nonlinear acoustics, interface modeling and characterization, UT transducers, new techniques, joined materials, probes and systems, fatigue cracks and fracture, imaging and sizing, NDE in engineering and process control, acoustics of cracks, and sensors. An author index is included. (DLC)

  20. Study on the Interrater Reliability of an OSPE (Objective Structured Practical Examination) – Subject to the Evaluation Mode in the Phantom Course of Operative Dentistry

    PubMed Central

    Schmitt, Laura; Möltner, Andreas; Rüttermann, Stefan; Gerhardt-Szép, Susanne

    2016-01-01

    Introduction: The aim of the study presented here was to evaluate the reliability of an OSPE end-of-semester exam in the phantom course for operative dentistry in Frankfurt am Main taking into consideration different modes of evaluation (examiner’s checklist versus instructor’s manual) and number of examiners (three versus four). Methods: In an historic, monocentric, comparative study, two different methods of evaluation were examined in a real end-of-semester setting held in OSPE form (Group I: exclusive use of an examiner’s checklist versus Group II: use of an examiner’s checklist including an instructor’s manual). For the analysis of interrater reliability, the generalisability theory was applied that contains a generalisation of the concept of internal consistency (Cronbach’s alpha). Results: The results show that the exclusive use of the examiner’s checklist led to higher interrater reliability values than the in-depth instructor’s manual used in addition to the list. Conclusion: In summary it can be said that the examiner’s checklists used in the present study, without the instructor’s manual, resulted in the highest interrater reliability in combination with three evaluators within the context of the completed OSPE. PMID:27579361

  1. Design considerations for NDE systems in a factory setting and the application to transmission manufacture at the Chrysler Transmission Plant in Kokomo, Indiana

    SciTech Connect

    LaChapell, M.; Perkins, D.E.; Schneberk, D.J.; Erb, S.H.; Nicholson, R.E.

    1994-10-01

    Chrysler Corp. and LLNL have entered into a collaboration to enhance the NDE technology at the Kokomo transmission plant. The project spans 3 years and a wide variety of different projects. Goals are making NDE automated, reliable, and capable of avoiding destructive testing. This requires NDE systems to be better utilized by quality teams on the shop floor and better connected for providing in one place a sufficient set of data for identifying problems in a manufacturing operation, and prescribing an adjustment. The approach is illustrated on two different processes, laser welding and pressure die casting; in each case data are combined from different NDE systems to enable a decision on an adjustment in process variables.

  2. NDE Assessments of Cast Stainless Steel Reactor Piping Components

    SciTech Connect

    Diaz, Aaron A.; Anderson, Michael T.; Cumblidge, Stephen E.; Doctor, Steven R.; Mathews, Royce

    2006-02-01

    Studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, have focused on developing and evaluating the effectiveness and reliability of novel NDE approaches for the inspection of coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the United States Nuclear Regulatory Commission (US NRC) on the utility, effectiveness and reliability of ultrasonic testing (UT) and eddy current testing (ET) inspection techniques as related to the in-service inspection of primary piping components in pressurized water reactors (PWRs). This paper describes recent developments and results from assessments of three different NDE approaches including an ultrasonic phased array inspection methodology, an eddy current testing technique and a low-frequency ultrasonic inspection methodology coupled with a synthetic aperture focusing technique (SAFT). Westinghouse Owner’s Group (WOG) cast stainless steel pipe segments with thermal and mechanical fatigue cracks located close to the weld roots, were used for assessing the inspection methods. ET studies were conducted on the inner diameter (ID) surface of piping specimens while the ultrasonic inspection methods were performed from the outer diameter (OD) surface of the specimens. The ET technique employed a ZETEC MIZ-27SI Eddy Current instrument and a ZETEC Z0000857-1 cross point spot probe with an operating frequency of 250 kHz. On some samples where noise levels were high, degaussing of the sample resulted in significant improvements. The phased array approach was implemented using an RD Tech Tomoscan III system operating at 1 MHz and composite volumetric images of the samples were generated. The low-frequency ultrasonic method employs a zone-focused, multi-incident angle; inspection protocol (operating at 250-450 kHz) coupled with a synthetic aperture focusing technique (SAFT) for improved signal-to-noise and advanced imaging

  3. NDE and SHM Simulation for CFRP Composites

    NASA Technical Reports Server (NTRS)

    Leckey, Cara A. C.; Parker, F. Raymond

    2014-01-01

    Ultrasound-based nondestructive evaluation (NDE) is a common technique for damage detection in composite materials. There is a need for advanced NDE that goes beyond damage detection to damage quantification and characterization in order to enable data driven prognostics. The damage types that exist in carbon fiber-reinforced polymer (CFRP) composites include microcracking and delaminations, and can be initiated and grown via impact forces (due to ground vehicles, tool drops, bird strikes, etc), fatigue, and extreme environmental changes. X-ray microfocus computed tomography data, among other methods, have shown that these damage types often result in voids/discontinuities of a complex volumetric shape. The specific damage geometry and location within ply layers affect damage growth. Realistic threedimensional NDE and structural health monitoring (SHM) simulations can aid in the development and optimization of damage quantification and characterization techniques. This paper is an overview of ongoing work towards realistic NDE and SHM simulation tools for composites, and also discusses NASA's need for such simulation tools in aeronautics and spaceflight. The paper describes the development and implementation of a custom ultrasound simulation tool that is used to model ultrasonic wave interaction with realistic 3-dimensional damage in CFRP composites. The custom code uses elastodynamic finite integration technique and is parallelized to run efficiently on computing cluster or multicore machines.

  4. Polymer Piezoelectric Transducers for Ultrasonic NDE

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Xue, Tianji; Lih, Shyh-Shiuh

    1996-01-01

    Piezoelectric polymers are associated with a low noise and inherent damping that makes them very effective receivers as well as broadband transmitters for high frequencies tasks. This paper reviews polymer piezoelectric materials, the origin of their piezoelectric behavior and their applications to ultrasonic NDE.

  5. Dose evaluation for paediatric chest x-ray examinations in Brazil and Sudan: low doses and reliable examinations can be achieved in developing countries

    NASA Astrophysics Data System (ADS)

    Mohamadain, K. E. M.; da Rosa, L. A. R.; Azevedo, A. C. P.; Guebel, M. R. N.; Boechat, M. C. B.; Habani, F.

    2004-03-01

    Radiation protection in paediatric radiology deserves special attention since it is assumed that children are more sensitive to radiation than adults. The aim of this work is to estimate the entrance skin dose (ESD), the body organ dose (BOD) and the effective dose (E) for chest x-ray exposure of paediatric patients in five large units, three in Sudan and two in Brazil, and to compare the results obtained in both countries with each other and with other values obtained by some European countries. Two examination projections have been investigated, namely, postero-anterior (PA) and antero-posterior (AP). The age intervals considered were: 0-1 year, 1-5 years, 5-10 years and 10-15 years. The results have been obtained with the use of a software called DoseCal. Results of mean ESD for the age interval 1-5 years and AP projection are: 66 µGy (Instituto de Pediatria e Puericultura Martagão Gesteira—IPPMG Hospital), 41, 86 and 68 µGy (Instituto Fernandes Figueira—IFF Hospital), 161 µGy (Omdurman Hospital), 395 µGy (Khartoum Hospital) and 23 µGy (Ahmed Gasim Hospital). In the case of the IFF Hospital, the results refer, respectively, to rooms 1, 2 and for the six mobile equipments. The reference dose values given by the European Guidelines were exceeded in the Khartoum Hospital whilst in all the other hospitals results obtained were below CEC reference values and comparable with the results found in Sweden, Germany, Spain and Italy. The mean E for the same age interval was 11 µSv in the IPPMG, 6, 15 and 11 µSv in the IFF, respectively for rooms 1, 2 and the 6 mobiles, 25 µSv in the Omdurman Hospital, 45 µSv in the Khartoum Hospital and 3 µSv in the Ahmed Gasim Hospital. These are some examples of the large discrepancies that have been detected in this survey.

  6. Manufacturing and NDE of Large Composite Aerospace Structures at MSFC

    NASA Technical Reports Server (NTRS)

    Whitaker, Ann

    2000-01-01

    NASA's vision for transportation to orbit calls for new vehicles built with new materials technology. The goals of this new launch system development are to improve safety, dramatically reduce cost to orbit, and improve vehicle turn around time. Planned Space Shuttle upgrades include new reusable liquid propellant boosters to replace the solid propellant boosters. These boosters are to have wings and return to the launch site for a horizontal landing on an airport runway. New single and two stages to orbit concepts are being investigated. To reduce weight and improve performance composite materials are proposed for fuel and oxidizer tanks, fuel feedlines, valve bodies, aerostructures, turbomachinery components. For large composite structures new methods of fabrication are being proposed and developed. Containment of cryogenic fuel or oxidizer requires emphases on composite material densification and chemical compatibility. Ceramic matrix and fiber composites for hot rotating turbomachinery have been developed with new fabrication processes. The new requirements on the materials for launcher components are requiring development of new manufacturing and inspection methods. This talk will examine new and proposed manufacturing methods to fabricate the revolutionary components. New NDE methods under consideration include alternative X-ray methods, X-ray laminagraphy, advanced CT, Thermography, new ultrasonic methods, and imbedded sensors. The sizes, complexity, use environment, and contamination restrictions will challenge the inspection process. In flight self-diagnosis and rapid depot inspection are also goals of the NDE development.

  7. The intra-examiner reliability of manual muscle testing of the hip and shoulder with a modified sphygmomanometer: a preliminary study of normal subjects

    PubMed Central

    Perossa, Daniel R; Dziak, Martin; Vernon, Howard T; Hayashita, Kaye

    1998-01-01

    The purpose of this study was to investigate the intrarater reliability of manual muscle assessment of the hip and shoulder using a modified sphygmomanometer. In addition, it was intended to establish a preliminary database of values from normal, healthy male and female volunteers. Eighty subjects participated in the test sessions, 40 males and 40 females between the ages of 19-22. Forty subjects participated in each of the hip and shoulder test sessions. Each examiner tested different paired movements on the subjects in one single session for the two separate joints. The tested movements consisted of hip extension, flexion and abduction and shoulder abduction, extension, flexion, internal and external rotation. All movements were tested by the patient-initiated method. Each movement was repeated twice, with a 30-35 second rest interval between the trials. The results showed that the intratester reliability coefficients for the hip ranged from 0.94-0.97, while, for the shoulder, the range was 0.86-0.97. Norms are expressed as mean (SD) values. These data conformed to previously established expectations, in that side-to-side differences were less than 10% and test values for males were larger than females in all tests. It was concluded that manual muscle assessment using a modified sphygmomanometer has acceptable intra-examiner reliability for the hip and shoulder when using the patient-initiated method. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7Figure 8

  8. How reliable are the risk estimates for X-ray examinations in forensic age estimations? A safety update.

    PubMed

    Ramsthaler, F; Proschek, P; Betz, W; Verhoff, M A

    2009-05-01

    Possible biological side effects of exposure to X-rays are stochastic effects such as carcinogenesis and genetic alterations. In recent years, a number of new studies have been published about the special cancer risk that children may suffer from diagnostic X-rays. Children and adolescents who constitute many of the probands in forensic age-estimation proceedings are considerably more sensitive to the carcinogenic risks of ionizing radiation than adults. Established doses for X-ray examinations in forensic age estimations vary from less than 0.1 microSv (left hand X-ray) up to more than 800 microSv (computed tomography). Computed tomography in children, as a relatively high-dose procedure, is of particular interest because the doses involved are near to the lower limit of the doses observed and analyzed in A-bombing survivor studies. From these studies, direct epidemiological data exist concerning the lifetime cancer risk. Since there is no medical indication for forensic age examinations, it should be stressed that only safe methods are generally acceptable. This paper reviews current knowledge on cancer risks associated with diagnostic radiation and aims to help forensic experts, dentists, and pediatricians evaluate the risk from radiation when using X-rays in age-estimation procedures. PMID:19153756

  9. Nuclear Technology Series. Course 32: Nondestructive Examination (NDE) Techniques II.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    This technical specialty course is one of thirty-five courses designed for use by two-year postsecondary institutions in five nuclear technician curriculum areas: (1) radiation protection technician, (2) nuclear instrumentation and control technician, (3) nuclear materials processing technician, (4) nuclear quality-assurance/quality-control…

  10. Nuclear Technology Series. Course 26: Nondestructive Examination (NDE) Techniques I.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    This technical specialty course is one of thirty-five courses designed for use by two-year postsecondary institutions in five nuclear technician curriculum areas: (1) radiation protection technician, (2) nuclear instrumentation and control technician, (3) nuclear materials processing technician, (4) nuclear quality-assurance/quality-control…

  11. Modeling ultrasonic NDE and guided wave based structural health monitoring

    NASA Astrophysics Data System (ADS)

    Ravi, Nitin B.; Rathod, Vivek T.; Chakraborty, Nibir.; Mahapatra, D. R.; Sridaran, Ramanan; Boller, Christian

    2015-04-01

    Structural Health Monitoring (SHM) systems require integration of non-destructive technologies into structural design and operational processes. Modeling and simulation of complex NDE inspection processes are important aspects in the development and deployment of SHM technologies. Ray tracing techniques are vital simulation tools to visualize the wave path inside a material. These techniques also help in optimizing the location of transducers and their orientation with respect to the zone of interrogation. It helps in increasing the chances of detection and identification of a flaw in that zone. While current state-of-the-art techniques such as ray tracing based on geometric principle help in such visualization, other information such as signal losses due to spherical or cylindrical shape of wave front are rarely taken into consideration. The problem becomes a little more complicated in the case of dispersive guided wave propagation and near-field defect scattering. We review the existing models and tools to perform ultrasonic NDE simulation in structural components. As an initial step, we develop a ray-tracing approach, where phase and spectral information are preserved. This enables one to study wave scattering beyond simple time of flight calculation of rays. Challenges in terms of theory and modelling of defects of various kinds are discussed. Various additional considerations such as signal decay and physics of scattering are reviewed and challenges involved in realistic computational implementation are discussed. Potential application of this approach to SHM system design is highlighted and by applying this to complex structural components such as airframe structures, SHM is demonstrated to provide additional value in terms of lighter weight and/or longevity enhancement resulting from an extension of the damage tolerance design principle not compromising safety and reliability.

  12. Electrostatic Capacitive Imaging: A New NDE Technique

    NASA Astrophysics Data System (ADS)

    Diamond, G.; Hutchins, D. A.; Leong, K. K.; Gan, T. H.

    2007-03-01

    A new technique for NDE has been developed which is capable of imaging a wide range of materials and structures, ranging from insulators to metallic conductors. The approach, known as Capacitive Imaging (CI) uses electrode arrays in air to produce an AC electric field distribution within the material. Scanning the electrodes over the material causes a change in the field distribution, and hence changes in output voltage. Capacitive coupling allows the technique to work on a wide variety of material conductivities without some of the disadvantages associated with conventional eddy current and potential drop methods. Images are presented of carbon fibre composite materials, concrete and Plexiglas, illustrating the range of application in NDE. The effect of electrode shape and excitation frequency will be discussed in terms of image resolution and depth of penetration.

  13. Additive manufacturing: Overview and NDE challenges

    NASA Astrophysics Data System (ADS)

    Slotwinski, J. A.

    2014-02-01

    Additive manufacturing (AM) processes are capable of producing highly complex and customized parts, without the need for dedicated tooling, and can produce parts directly from the part design information. These types of processes are poised to revolutionize the manufacturing industry, yet there are several challenges that are currently preventing more widespread adoption of AM technologies. Traditional Non-Destructive Evaluation (NDE) methods could be utilized in both in-process and post-process applications to help overcome these challenges, although currently there are very few examples of in-situ sensors for monitoring AM processes. This paper gives an overview of AM technology, and discusses the potential benefits and challenges of using NDE in AM applications.

  14. NASA DOEPOD NDE Capabilities Data Book

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    2015-01-01

    This data book contains the Directed Design of Experiments for Validating Probability of Detection (POD) Capability of NDE Systems (DOEPOD) analyses of the nondestructive inspection data presented in the NTIAC, Nondestructive Evaluation (NDE) Capabilities Data Book. DOEPOD is designed as a decision support system to validate inspection system, personnel, and protocol demonstrating 0.90 POD with 95% confidence at critical flaw sizes, a90/95. Although 0.90 POD with 95% confidence at critical flaw sizes is often stated as an inspection requirement in inspection documents, including NASA Standards, NASA critical aerospace applications have historically only accepted 0.978 POD or better with a 95% one-sided lower confidence bound exceeding 0.90 at critical flaw sizes, a90/95.

  15. Quantitative NDE applied to composites and metals

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S.; Winfree, William P.; Parker, F. Raymond; Heath, D. Michele; Welch, Christopher S.

    1989-01-01

    Research at the NASA/Langley Research Center concerning quantitative NDE of composites and metals is reviewed. The relationship between ultrasonics and polymer cure is outlined. NDE models are presented, which can be used to develop measurement technologies for characterizing the curing of a polymer system for composite materials. The models can be used to determine the glass transition temperature, the degree of cure, and the cure rate. The application of the model to control autoclave processing of composite materials is noted. Consideration is given to the use of thermal diffusion models combined with controlled thermal input measurements to determine the thermal diffusivity of materials. Also, a two-dimensional physical model is described that permits delaminations in samples of Space Shuttle Solid Rocket Motors to be detected in thermograms in the presence of cooling effects and uneven heating.

  16. NDE and the microgravity sciences at NASA

    NASA Astrophysics Data System (ADS)

    Roth, D. J.

    2002-05-01

    NASA has programs in the physical and life sciences areas that include micro- and variable-gravity-based science, and offers very unique facilities including ground- and space-based facilities to support this science. For the physical microgravity sciences, areas of investigation include biotechnology, combustion science, fluid physics, fundamental physics, and materials science. A reformulation of the physical sciences program is underway in which the "stovepipe" disciplines will be combined over time to form interdisciplinary themes. This article will focus on what role NDE has played in the microgravity sciences area to date, which has primarily been as a support technology for monitoring and recording results of discipline-based microgravity research. Additionally, a proposed experiment is described that will investigate how microgravity affects a fundamental NDE process: that of air-coupled ultrasonic wave propagation. A review of basic microgravity concepts will be provided including the various facilities that NASA has to create a microgravity environment (including drop towers, aircraft, rockets, space shuttle, and the International Space Station). Applications of NDE for Life Science experiments will be briefly mentioned.

  17. NDE of Possible Service-Induced PWSCC in Control Rod Drive Mechanism Housings Removed from Service

    SciTech Connect

    Cumblidge, Stephen E.; Doctor, Steven R.; Schuster, George J.; Harris, Robert V.; Crawford, Susan L.

    2006-09-22

    Studies being conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington are being performed to assess the effectiveness of nondestructive examination (NDE) techniques on removed-from-service control rod drive mechanism (CRDM) nozzles and the associated J-groove attachment welds. This work is being performed to provide information to the United States Nuclear Regulatory Commission (US NRC) on the effectiveness of NDE techniques such as ultrasonic testing (UT), eddy current testing (ET), and visual testing (VT) as related to the in-service inspection of CRDM nozzles and J-groove weldments, and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies. The basic NDE measurements follow standard industry techniques for conducting in-service inspections of CRDM nozzles and the crown of the J-groove welds and buttering. In addition, laboratory-based NDE methods were employed to conduct inspections of the CRDM assemblies, with particular emphasis on the J-groove weld and buttering. This paper describes the NDE measurements that were employed on the two CRDMs to detect and characterize the indications and the analysis of these indications. The two CRDM assemblies were removed from service from the North Anna 2 vessel head, including the CRDM nozzle, the J-groove weld, buttering, and a portion of the ferritic head material. One nozzle contains suspected PWSCC, based on in-service inspection data; the second contains evidence suggesting through-wall leakage, although this was unconfirmed. A destructive test plan is being developed to directly characterize the indications found using nondestructive testing. The results of this destructive testing will be included when the destructive testing is completed.

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

    NASA Technical Reports Server (NTRS)

    Generazio, Ed

    2005-01-01

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

  19. On-orbit NDE: A novel approach to tube weld inspection

    NASA Technical Reports Server (NTRS)

    Michaels, Kerry; Hughes, Greg

    1994-01-01

    The challenge of fabrication and repair of structures in space must be met if we are to utilize and maintain long-duration space facilities. Welding techniques have been demonstrated to provide the most reliable means to accomplish this task. Over the past few years, methods have been developed to perform orbital tube welding employing space-based welding technology pioneered by the former Soviet Union. Welding can result in the formation of defects, which threaten the structural integrity of the welded joint. Implementation of welding on-orbit, therefore, must also include methods to evaluate the quality and integrity of the welded joints. To achieve this goal, the development of an on-orbit tube weld inspection system, utilizing alternating current field measurement (ACFM) technology, has been under taken. This paper describes the development of the ACFM on-orbit tube weld inspection tool. Topics discussed include: requirements for on-orbit NDE, basic theory of ACFM, its advantages over other NDE methods for on-orbit applications, and the ACFM NDE system design. System operation and trial inspection results are also discussed. Future work with this technology is also considered.

  20. NASA Engineering and Safety Center NDE Super Problem Resolution Team

    NASA Astrophysics Data System (ADS)

    Prosser, W. H.

    2007-03-01

    The NASA Engineering and Safety Center (NESC) is an independent organization, which was charted in the wake of the Space Shuttle Columbia accident to serve as an Agency-wide technical resource focused on engineering excellence. The objective of the NESC is to improve safety by performing in-depth independent engineering assessments, testing, and analysis to uncover technical vulnerabilities and to determine appropriate preventative and corrective actions for problems, trends or issues within NASA's programs, projects and institutions. Critical to the NESC are teams of experts in a number of core disciplines including nondestructive evaluation (NDE). These teams, designated Super Problem Resolution Teams (SPRTs), draw upon the best engineering expertise from across the Agency and include partnerships with other government agencies, national laboratories, universities and industry. The NESC NDE SPRT provides a ready resource of NDE technical expertise to support NESC Independent Technical Assessments and Investigations. The purpose of this session will be to provide an overview of the NESC and the NDE SPRT along with a few examples of NDE related problems that the team has addressed for NASA Programs. It is hoped that this session will be of interest to the general NDE community and will foster contacts with additional NDE experts that might provide future support to the NASA NESC NDE SPRT.

  1. Nondestructive Evaluation (NDE) research progress in 1988: Proceedings from the ninth annual EPRI NDE information meeting

    SciTech Connect

    Avioli, M.J. Jr.; Dau, G.J.; Liu, S.N.; Stein, J.; Welty, C.S.

    1989-05-01

    The increasing cost of equipment for power generating plants and the potential increases in productivity and safety analysis through rapidly developing Nondestructive Evaluation (NDE) technology led EPRI to initiate a Nondestructive Evaluation Program in 1974. To date, the major focus has been on light water reactor inspection problems; however, increased application to other systems is now underway. This report presents a comprehensive review of the EPRI effort in the NDE area. Most of the report consists of contractor-supplied progress reports on each current project. An organizational plan of the program is presented in overview. In addition, organization from several viewpoints is presented, e.g., in-service inspection operators, R and D personnel, and utility representatives. As the tenth in a planned series of annual progress reports of EPRI-funded NDE activities, this report also serves as the proceedings of the Ninth Annual EPRI NDE Information Meeting held in Charlotte, North Carolina, on November 15--16, 1988. It summarizes significant progress made since the previous EPRI Special Report NP-5490-SR was issued in June 1988. Section 1 contains information about the program organization, and the sections that follow contain contractor-supplied progress reports on each current project. The progress reports are grouped by plant components -- pipe, pressure vessel, and steam generator and boiler tubes. In addition, Part 5 is devoted to discussions of technology transfer.

  2. Probabilistic collocation method for NDE problems with uncertain parameters with arbitrary distributions

    NASA Astrophysics Data System (ADS)

    Cherry, M. R.; Knopp, J. S.; Blodgett, M. P.

    2012-05-01

    In order to quantify the reliability of NDE systems, large numbers of experiments are performed to develop a probability of detection (POD) curve for the system. These POD studies require a substantial amount of experimentation which can sometimes be cost prohibitive. To expedite the process of developing these curves, highly precise numerical models are used in conjunction with NDE sensors to understand the uncertainties associated with the inspections. Numerical models are also used in stochastic inversion methods such as Bayesian inversion, which provide a means of characterizing system properties with uncertainties. A strong basis has been developed in the modeling and simulation community for deterministic forward models in NDE, but to fully incorporate these models in model-assisted probability of detection (MAPOD) studies or stochastic inversion schemes, the models must be treated in a stochastic sense. A method of taking random inputs to a "black box" forward model and developing the full probability distribution function (PDF) of the response has been proposed. This method, called the probabilistic collocation method (PCM), takes random inputs to a forward model and uses orthogonal polynomials to construct a surrogate model in the area of the expected values of the inputs which is solved much quicker than the original forward model. In the NDE community, this method has only been used with inputs of known, named distributions. In this work, inputs of arbitrary distribution were used and the orthogonal polynomials for these inputs were developed with a recursion relationship that has been shown to produce orthogonal polynomials with respect to a given, continuous function. A concise code was written to make testing the method and incorporating it into MAPOD studies and inversion schemes relatively easy. The routine was tested with academic problems as well as eddy current problems.

  3. NDE in aerospace - Requirements for science, sensors and sense

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S.

    1989-01-01

    The complexity of modern nondestructive evaluation (NDE) arises from four main factors: quantitative measurement science, physical models for computational analysis, realistic interfacing with engineering decisions, and direct access to management priorities. Recent advances in the four factors of NDE are addressed. Physical models of acoustic propagation are presented that have led to the development of measurement technologies advancing the ability to assure that materials and structures will perform as designed. In addition, a brief discussion is given of current research for future mission needs such as smart structures that sense their own health. Such advances permit projects to integrate design for inspection into their plans, bringing NDE into engineering and management priorities. The measurement focus is on ultrasonics with generous case examples. Problem solutions highlighted include critical stress in fasteners, residual stress in steel, NDE laminography, and solid rocket motor NDE.

  4. NDE in aerospace-requirements for science, sensors and sense.

    PubMed

    Heyman, J S

    1989-01-01

    The complexity of modern NDE (nondestructive evaluation) arises from four main factors: quantitative measurement, science, physical models for computational analysis, realistic interfacing with engineering decisions, and direct access to management priorities. Recent advances in the four factors of NDE are addressed. Physical models of acoustic propagation are presented that have led to the development of measurement technologies advancing the ability to assure that materials and structures will perform a design. In addition, a brief discussion is given of current research for future mission needs such as smart structures that sense their own health. Such advances permit projects to integrate design for inspection into their plans, bringing NDE into engineering and management priorities. The measurement focus is on ultrasonics with generous case examples. Problem solutions highlighted include critical stress in fasteners, residual stress in steel, NDE laminography, and solid rocket motor NDE. PMID:18290237

  5. NDE to Manage Atmospheric SCC in Canisters for Dry Storage of Spent Fuel: An Assessment

    SciTech Connect

    Meyer, Ryan M.; Pardini, Allan F.; Cuta, Judith M.; Adkins, Harold E.; Casella, Andrew M.; Qiao, Hong; Larche, Michael R.; Diaz, Aaron A.; Doctor, Steven R.

    2013-09-01

    This report documents efforts to assess representative horizontal (Transuclear NUHOMS®) and vertical (Holtec HI-STORM) storage systems for the implementation of non-destructive examination (NDE) methods or techniques to manage atmospheric stress corrosion cracking (SCC) in canisters for dry storage of used nuclear fuel. The assessment is conducted by assessing accessibility and deployment, environmental compatibility, and applicability of NDE methods. A recommendation of this assessment is to focus on bulk ultrasonic and eddy current techniques for direct canister monitoring of atmospheric SCC. This assessment also highlights canister regions that may be most vulnerable to atmospheric SCC to guide the use of bulk ultrasonic and eddy current examinations. An assessment of accessibility also identifies canister regions that are easiest and more difficult to access through the ventilation paths of the concrete shielding modules. A conceivable sampling strategy for canister inspections is to sample only the easiest to access portions of vulnerable regions. There are aspects to performing an NDE inspection of dry canister storage system (DCSS) canisters for atmospheric SCC that have not been addressed in previous performance studies. These aspects provide the basis for recommendations of future efforts to determine the capability and performance of eddy current and bulk ultrasonic examinations for atmospheric SCC in DCSS canisters. Finally, other important areas of investigation are identified including the development of instrumented surveillance specimens to identify when conditions are conducive for atmospheric SCC, characterization of atmospheric SCC morphology, and an assessment of air flow patterns over canister surfaces and their influence on chloride deposition.

  6. Measurement of body dissatisfaction in college-enrolled Mexican American Women: A Rasch-based examination of the validity and reliability of the EDI-III.

    PubMed

    Stein, Karen Farchaus; Riley, Barth Brian; Hoyland-Domenico, Lisa; Lee, Chia-Kuei

    2015-12-01

    Measures of body dissatisfaction have not been validated for Mexican American (MA) women, who evaluate their bodies differently than Caucasian women. In this study, the psychometric properties of the EDI-III, Body Dissatisfaction Subscale (BDS) were examined in a sample of college-enrolled MA women using the Rasch Rating Scale Model. Criterion validity was also addressed. BDS evidenced good item fit, person and item reliability, once poorly correlated items were removed. Two qualitatively distinct dimensions of body dissatisfaction were identified: (1) overall body shape and stomach, and (2) the lower body. Validity of the scales was supported. Results suggest: MA women's satisfaction with overall body shape is not synonymous with attitudes toward their lower body. PMID:26164669

  7. Reliability Generalization: "Lapsus Linguae"

    ERIC Educational Resources Information Center

    Smith, Julie M.

    2011-01-01

    This study examines the proposed Reliability Generalization (RG) method for studying reliability. RG employs the application of meta-analytic techniques similar to those used in validity generalization studies to examine reliability coefficients. This study explains why RG does not provide a proper research method for the study of reliability,…

  8. NDE and mechanical removal of sludge in PWR steam generators: Volume 2, Vendor practices: Final report

    SciTech Connect

    Kidd, C.C.; Scharton, T.D.; Spencer, R.B.; Taylor, G.B.; Stewart, D.R.; Gallagher, M.J.; Johnson, L.E.; Sapia, M.A.; Edwards, L.J.; Dashukewich, M.L.

    1988-01-01

    A study was made to identify the needs of utilities for detecting, measuring, and mechanically removing sludge and related corrosion products from PWR steam generators, both recirculating U-tube and once through designs. The study determining, from the utility-user viewpoint, how well these needs are being met by currently available technology; identified opportunities for improvement; and made recommendations for research efforts to realize these opportunities. Methods for chemically removing sludge and corrosion products from steam generators, i.e., use of chemical solvents, were not addressed. Reports from nuclear steam supply system vendors and independent service vendors on their current processes and prior developmental efforts to realize these opportunities. Methods for chemically removing sludge and corrosion products from steam generators, i.e., use of chemical solvents, were not addressed. Reports from nuclear steam supply system vendors and independent service vendors on their current processes and prior developmental efforts with mechanical removal methods and NDE techniques are included in the study. In addition, information was obtained from the technical literature and from discussions and visits with knowledgeable individuals at utilities, service vendors, and engineering and consulting firms. Current removal methods examined included sludge lancing, pressure pulse and water slap; current NDE techniques examined included eddy current, optical instruments, sludge sampling, and water balance measurements. Additional NDE techniques reported on by the service vendors included Hall effect and magnetic field sensing probes, ultrasonic, and radiation attenuation techniques.

  9. Application of NDE in aerospace coatings

    NASA Astrophysics Data System (ADS)

    Fahr, Abbas; Giguere, Sylvain; Roge, Bruno; McRae, Kenneth

    2002-06-01

    Wear resistant cermet coatings are used in aircraft landing gears and thermal barrier coatings (TBC) are applied to hot- section components of turbine engines. A series of experiments have been conducted to characterize cermet and TBC coatings using NDE techniques. A cermet coating is tested using conventional ultrasonic and eddy current methods as well as an ultrasonic leaky surface wave technique. The results demonstrate the ability of these techniques to detect the presence of defects on the surface or beneath the surface of the coating and at the coating- substrate interface. Ultrasonic time-of-flight and eddy current quadrature measurements also show the ability to detect minute changes in the thickness of cermet coatings. Knowing the coating thickness, the density of the coating is estimated by comparison of the theoretical and the experimental transfer functions of the ultrasonic signals. NDE techniques were also used to inspect thermal barrier coatings. In particular, eddy current technique was used to measure the thickness of plasma-sprayed TBC specimens, and knowing the thickness, ultrasonic techniques were applied to obtain an estimate of the porosity content.

  10. Terahertz NDE for Metallic Surface Roughness Evaluation

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I.; Anastasi, Robert F.

    2006-01-01

    Metallic surface roughness in a nominally smooth surface is a potential indication of material degradation or damage. When the surface is coated or covered with an opaque dielectric material, such as paint or insulation, then inspecting for surface changes becomes almost impossible. Terahertz NDE is a method capable of penetrating the coating and inspecting the metallic surface. The terahertz frequency regime is between 100 GHz and 10 THz and has a free space wavelength of 300 micrometers at 1 THz. Pulsed terahertz radiation, can be generated and detected using optical excitation of biased semiconductors with femtosecond laser pulses. The resulting time domain signal is 320 picoseconds in duration. In this application, samples are inspected with a commercial terahertz NDE system that scans the sample and generates a set of time-domain signals that are a function of the backscatter from the metallic surface. Post processing is then performed in the time and frequency domains to generate C-scan type images that show scattering effects due to surface non-uniformity.

  11. NDE standards for high temperature materials

    NASA Technical Reports Server (NTRS)

    Vary, Alex

    1991-01-01

    High temperature materials include monolithic ceramics for automotive gas turbine engines and also metallic/intermetallic and ceramic matrix composites for a range of aerospace applications. These are materials that can withstand extreme operating temperatures that will prevail in advanced high-efficiency gas turbine engines. High temperature engine components are very likely to consist of complex composite structures with three-dimensionality interwoven and various intermixed ceramic fibers. The thermomechanical properties of components made of these materials are actually created in-place during processing and fabrication stages. The complex nature of these new materials creates strong incentives for exact standards for unambiguous evaluations of defects and microstructural characteristics. NDE techniques and standards that will ultimately be applicable to production and quality control of high temperature materials and structures are still emerging. The needs range from flaw detection to below 100 micron levels in monolithic ceramics to global imaging of fiber architecture and matrix densification anomalies in composites. The needs are different depending on the processing stage, fabrication method, and nature of the finished product. The standards are discussed that must be developed in concert with advances in NDE technology, materials processing research, and fabrication development. High temperature materials and structures that fail to meet stringent specifications and standards are unlikely to compete successfully either technologically or in international markets.

  12. Assessment of NDE Methods to Detect Lack of Fusion in HDPE Butt Fusion Joints

    SciTech Connect

    Crawford, Susan L.; Doctor, Steven R.; Cinson, Anthony D.; Watts, Michael W.; Moran, Traci L.; Anderson, Michael T.

    2011-07-31

    Studies at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, were conducted to evaluate nondestructive examinations (NDE) coupled with mechanical testing of butt fusion joints in high-density polyethylene (HDPE) pipe for assessing lack of fusion. The work provided information to the United States Nuclear Regulatory Commission (NRC) on the effectiveness of volumetric inspection techniques of HDPE butt fusion joints in Section III, Division 1, Class 3, buried piping systems in nuclear power plants. This paper describes results from assessments using ultrasonic and microwave nondestructive techniques and mechanical testing with the high-speed tensile impact test and the side-bend test for determining joint integrity. A series of butt joints were fabricated in 3408, 12-inch (30.5-cm) IPS DR-11 HDPE material by varying the fusion parameters to create good joints and joints containing a range of lack-of-fusion conditions. Six of these butt joints were volumetrically examined with time-of-flight diffraction (TOFD), phased-array (PA) ultrasound, and the Evisive microwave system. The outer diameter (OD) weld beads were removed for microwave evaluation and the pipes ultrasonically re-evaluated. In two of the six pipes, both the outer and inner diameter (ID) weld beads were removed and the pipe joints re-evaluated. Some of the pipes were sectioned and the joints destructively evaluated with the high-speed tensile test and the side-bend test. The fusion parameters, nondestructive and destructive evaluation results have been correlated to validate the effectiveness of what each NDE technology detects and what each does not detect. There was no single NDE method that detected all of the lack-of-fusion flaws but a combination of NDE methods did detect most of the flaws.

  13. Nde Challenges with Future Commercial Aircraft-A Boeing Perspective

    NASA Astrophysics Data System (ADS)

    Kollgaard, J. R.; LaRiviere, S. G.

    2008-02-01

    Commercial aircraft have undergone revolutionary changes in design, configuration and materials. This produces new challenges to the NDE community ranging from process controls of raw materials, to testing and fabrication of structural components, to service damage assessments. As we drive NDE up the value stream, it will become imperative to understand variousprocess parameters and their relationship to product quality. NDE may play a key role in characterizing and controlling those parameters. In production, inspection has become a critical aspect in the processing of large, unitized structures. Penetrant, radiographic, and magnetic particle techniques are less applicable while ultrasonics has taken on a critical role, earlier in the build process. NDE data are acquired over large areas at rates far faster than before, creating challenges in the time required to analyze and document the data. Qualified inspectors, equipment, and techniques are essential. In the field, eddy current and shear wave ultrasonic methods, long a mainstay of aircraft maintenance, are beginning to yield to ultrasonic techniques involving C-scans and linear arrays. The building of new-generation airplanes has revealed shortcomings in existing NDE technology and in some cases enhanced the case for non-traditional methods. This paper will review Boeing's experience with NDE of advanced structures, in particular those present on the Boeing 787, and summarize the Boeing outlook for future NDE needs.

  14. Nondestructive examination development and demonstration plan

    SciTech Connect

    Weber, J.R.

    1991-08-21

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

  15. Application of Hilbert-Huang Transform for Improved Defect Detection in Terahertz NDE of Shuttle Tiles

    NASA Technical Reports Server (NTRS)

    Anastasi, Robert F.; Madaras, Eric I.

    2005-01-01

    Terahertz NDE is being examined as a method to inspect the adhesive bond-line of Space Shuttle tiles for defects. Terahertz signals are generated and detected, using optical excitation of biased semiconductors with femtosecond laser pulses. Shuttle tile samples were manufactured with defects that included repair regions unbond regions, and other conditions that occur in Shuttle structures. These samples were inspected with a commercial terahertz NDE system that scanned a tile and generated a data set of RF signals. The signals were post processed to generate C-scan type images that are typically seen in ultrasonic NDE. To improve defect visualization the Hilbert-Huang Transform, a transform that decomposes a signal into oscillating components called intrinsic mode functions, was applied to test signals identified as being in and out of the defect regions and then on a complete data set. As expected with this transform, the results showed that the decomposed low-order modes correspond to signal noise while the high-order modes correspond to low frequency oscillations in the signal and mid-order modes correspond to local signal oscillations. The local oscillations compare well with various reflection interfaces and the defect locations in the original signal.

  16. Materials characterization and flaw detection by acoustic NDE

    NASA Astrophysics Data System (ADS)

    Buck, Otto

    1992-10-01

    This overview lists the potential applications of acoustic NDE for characterizing and assessing structural inhomogeneities in varied materials. Acoustic NDE is discussed in terms of its application to inhomogeneities such as: interstitials, precipitates, dislocations, phase transformations, porosity, cracks, and dislocation-point defect interactions. Acoustic velocity measurements provide data on interstitial concentrations, and nonlinear acoustics can describe the volume fraction of second-phase precipitates. Ultrasonic NDE can be used to determine the oxygen present in Ti-6211, binary alloys, and other alloys, and theoretical progress is noted in the characterization of porosity and cracks by means of sound velocity and attenuation as well as backscattering. Quantitative acoustic NDE can be used to detect flaws and characterize materials both during processing and by means of periodic inspections.

  17. Use of the consultation satisfaction questionnaire to examine patients' satisfaction with general practitioners and community nurses: reliability, replicability and discriminant validity.

    PubMed Central

    Poulton, B C

    1996-01-01

    BACKGROUND: Primary health care services are the most frequently used in the health care system. Consumer feedback on these services is important. Research in this area relates mainly to doctor-patient relationships which fails to reflect the multidisciplinary nature of primary health care. AIM: A pilot study aimed to examine the feasibility of using a patient satisfaction questionnaire designed for use with general practitioner consultations as an instrument for measuring patient satisfaction with community nurses. METHOD: The questionnaire measuring patient satisfaction with general practitioner consultations was adapted for measuring satisfaction with contacts with a nurse practitioner, district nurses, practice nurses and health visitors. A total of 1575 patients in three practices consulting general practitioners or community nurses were invited to complete a questionnaire. Data were subjected to principal components analysis and the dimensions identified were tested for internal reliability and replicability. To establish discriminant validity, patients' mean satisfaction scores for consultations with general practitioners, the nurse practitioner, health visitors and nurses (district and practice nurses) were compared. RESULTS: Questionnaires were returned relating to 400 general practitioner, 54 nurse practitioner, 191 district/practice nurse and 83 health visitor consultations (overall response rate 46%). Principal components analysis demonstrated a factor structure similar to that found in an earlier study of the consultation satisfaction questionnaire. Three dimensions of patient satisfaction were identified: professional care, depth of relationship and perceived time spent with the health professional. The dimensions were found to have acceptable levels of reliability. Factor structures obtained from data relating to general practitioner and community nurse consultations were found to correlate significantly. Comparison between health professionals

  18. Contamination detection NDE for cleaning process inspection

    NASA Technical Reports Server (NTRS)

    Marinelli, W. J.; Dicristina, V.; Sonnenfroh, D.; Blair, D.

    1995-01-01

    In the joining of multilayer materials, and in welding, the cleanliness of the joining surface may play a large role in the quality of the resulting bond. No non-intrusive techniques are currently available for the rapid measurement of contamination on large or irregularly shaped structures prior to the joining process. An innovative technique for the measurement of contaminant levels in these structures using laser based imaging is presented. The approach uses an ultraviolet excimer laser to illuminate large and/or irregular surface areas. The UV light induces fluorescence and is scattered from the contaminants. The illuminated area is viewed by an image-intensified CCD (charge coupled device) camera interfaced to a PC-based computer. The camera measures the fluorescence and/or scattering from the contaminants for comparison with established standards. Single shot measurements of contamination levels are possible. Hence, the technique may be used for on-line NDE testing during manufacturing processes.

  19. Porosity estimation of concrete by ultrasonic NDE

    PubMed

    Hernandez; Izquierdo; Ibanez; Anaya; Ullate

    2000-03-01

    The increasing number of concrete structures with symptoms of premature deterioration due to environmental action demands procedures to estimate the durability of this type of component. Concrete durability is related to porosity, which determines the intensity of interactions of the material with aggressive agents. The pores and capillaries inside the structure facilitate the destructive processes that generally begin in the surface. In this work, an ultrasonic NDE technique to estimate the porosity of concrete is developed. The method is based on the analysis of the mechanical behaviour of mortar probes built with calibrated sand, in which the concentration of water-cement mixture has been varied. In this sense, data of sound velocity are correlated with data of porosity, which have been previously measured by destructive measurements. PMID:10829720

  20. Understanding Schools as High-Reliability Organizations: An Exploratory Examination of Teachers' and School Leaders' Perceptions of Success

    ERIC Educational Resources Information Center

    Lorton, Juli A.; Bellamy, G. Thomas; Reece, Anne; Carlson, Jill

    2013-01-01

    Drawing on research on high-reliability organizations, this interviewbased qualitative case study employs four characteristics of such organizations as a lens for analyzing the operations of one very successful K-5 public school. Results suggest that the school had processes similar to those characteristic of high-reliability organizations: a…

  1. Detection sensitivity of x-ray CT imaging for NDE of green-state ceramics

    SciTech Connect

    Gopalsami, N.; Rizo, P.; Ellingson, W.A. ); Tracey, D.M. . Advanced Ceramics Div.)

    1991-01-01

    Improved ceramic-processing methods that use pressure slip-casting and injection molding are being developed at Norton Advanced Ceramics, with a goal of producing reliable structural ceramics for advanced heat engines. Nondestructive evaluation (NDE) of ceramic parts at different stages of processing can provide useful diagnostic information to help improve processing techniques. For example, an evaluation of density gradients in as-cast green-body samples can be used to judge mold performance and make changes in mold design. Also, the ability to detect minute flaws (20 to 50 {mu}m), such as agglomerates, inclusions, and voids, in green-body, presintered, and densified parts is important in ensuring structural reliability of the final parts, because these flaws, above certain critical sizes, can lead to catastrophic failure. Three-dimensional microfocus X-ray computed tomography (CT) and nuclear magnetic resonance imaging (MRI) systems have been developed at Argonne National Laboratory (ANL) for application to quantitative NDE evaluation of ceramics. This paper evaluates the detection sensitivity of the ANL X-ray CT system when used to determine density gradients, inclusions, and voids in green-state Si{sub 3}N{sub 4} ceramics. A theoretical account of key system- and sample-related parameters affecting X-ray CT detection sensitivity is given, and results of experimental evaluation are presented. Density calibration phantoms and net-shape-formed tensile rods with seeded defects were used in the experimental evaluation of detection limits. 6 refs., 6 figs., 1 tab.

  2. Life assessment of boiler pressure parts. Volume 6, Guidelines for NDE of heavy section components: Final report

    SciTech Connect

    Grunloh, H.J.; Hoosic, P.T.; Berasi, M.L.; Sherlock, T.P.; Evans, R.S.; Lawrie, W.E.; Buttram, J.D.; Flora, J.H.

    1993-11-01

    The use of nondestructive techniques to assess current condition of metallic components is an integral part of the life assessment methodology developed under the RP2253-10 project and incorporated into the BLESS code. This report provides an overview of the applicable NDE methods currently available and gives detailed guidelines on their use in assessing the condition of the material in elevated temperature headers and pipes. The overview covers visual, dimensional, magnetic particle, liquid penetrant, metallographic replication, radiographic, eddy current, ultrasonic, nuclear fluorescence, electromagnetic acoustic, and acoustic emission nondestructive examination methods. A discussion of typical damage mechanisms observed in heavy section components is provided covering both high and low temperature power plant headers and pipes. Detailed guidelines on the use of the various techniques are given, including guidance on flaw disposition. Detailed and specific procedural aspects are covered in extensive appendices on ultrasonic detection, surface preparation for NDE, magnetic particle examination, and liquid penetrant examination.

  3. Fatigue strength reduction factors for welds based on nondestructive examination

    SciTech Connect

    Hechmer, J.L.; Kuhn, E.J. III

    1999-02-01

    Based on the author`s hypothesis that nondestructive examination (NDE) has a major role in predicting the fatigue life of pressure vessels, a project was initiated to develop a defined relationship between NDE and fatigue strength reduction factors (FSRF). Even though a relationship should apply to both base metal and weld metal, the project was limited to weld metal because NDE for base metal is reasonably well established, whereas NDE for weld metal is more variable, depending on application. A matrix of FSRF was developed based on weld type (full penetration, partial penetration, and fillet weld) versus the NDE that is applied. The NDE methods that are included are radiographic testing (RT), ultrasonic testing (UT), magnetic particle testing (MT), dye penetrant testing (PT), and visual testing (VT). The first two methods (RT and UT) are volumetric examinations, and the remaining three are surface examinations. Seven combinations of volumetric and surface examinations were defined; thus, seven levels of FSRF are defined. Following the initial development of the project, a PVRC (Pressure Vessel Research Council) grant was obtained for the purpose of having a broad review. The report (Hechmer, 1998) has been accepted by PVRC. This paper presents the final matrix, the basis for the FSRF, and key definitions for accurate application of the FSRF matrix. A substantial amount of additional information is presented in the PVRC report (Hechmer, 1998).

  4. Investigation of a comprehensive confidence measure in NDE

    NASA Astrophysics Data System (ADS)

    Banerjee, Portia; Safdarnejad, Seyed; Udpa, Lalita; Udpa, Satish

    2015-03-01

    Quantitative assessment of reliability of classification results is critical in detection and characterization of anomalies in any non-destructive evaluation (NDE) application. Particularly in automated data analysis systems, such a measure enables the system to automatically flag indications where operator intervention is required, and reduces maintenance costs and risks. Classification results are affected by inherent ambiguity of defect classes, non-discriminative features, inadequate training samples and poor data quality. Although these sources of uncertainties in classification have been studied, formulating a single measure which quantifies all of them together has not been done to date. Generally, from Bayesian point of view, the posterior probability is considered as a confidence measure. Posterior probability of occurrence of an event is representative of inter-class similarities and intra-class distance and thus, may be used as a measure of inherent ambiguity of classes and discriminative quality of features. However, estimation of posterior probability itself is affected by size of available training samples. In this paper, we develop a framework to incorporate these two major sources of classification error in a single quantity. In lieu of the simplistic assumption, we assume that parameters of the distribution of a class are random variables. We utilize bootstrap method to find empirical distribution of parameters of the class conditional densities based on which a distribution of confidence is found. Utilizing this distribution, different interpretations of the confidence measure may be provided. Analytical results show how statistical properties of the confidence distribution depend on number of training samples and quality of features. Initial results of the approach on eddy current data is presented.

  5. The History and Future of NDE in the Management of Nuclear Power Plant Materials Degradation

    SciTech Connect

    Doctor, Steven R.

    2009-04-01

    The author has spent more than 25 years conducting engineering and research studies to quantify the performance of nondestructive evaluation (NDE) in nuclear power plant (NPP) applications and identifying improvements to codes and standards for NDE to manage materials degradation. This paper will review this fundamental NDE engineering/research work and then look to the future on how NDE can be optimized for proactively managing materials degradation in NPP components.

  6. Rough surface reconstruction for ultrasonic NDE simulation

    SciTech Connect

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

    2014-02-18

    The reflection of ultrasound from rough surfaces is an important topic for the NDE of safety-critical components, such as pressure-containing components in power stations. The specular reflection from a rough surface of a defect is normally lower than it would be from a flat surface, so it is typical to apply a safety factor in order that justification cases for inspection planning are conservative. The study of the statistics of the rough surfaces that might be expected in candidate defects according to materials and loading, and the reflections from them, can be useful to develop arguments for realistic safety factors. This paper presents a study of real rough crack surfaces that are representative of the potential defects in pressure-containing power plant. Two-dimensional (area) values of the height of the roughness have been measured and their statistics analysed. Then a means to reconstruct model cases with similar statistics, so as to enable the creation of multiple realistic realizations of the surfaces, has been investigated, using random field theory. Rough surfaces are reconstructed, based on a real surface, and results for these two-dimensional descriptions of the original surface have been compared with those from the conventional model based on a one-dimensional correlation coefficient function. In addition, ultrasonic reflections from them are simulated using a finite element method.

  7. Study Methods to Standardize Thermography NDE

    NASA Technical Reports Server (NTRS)

    Walker, James L.; Workman, Gary L.

    1998-01-01

    The purpose of this work is to develop thermographic inspection methods and standards for use in evaluating structural composites and aerospace hardware. Qualification techniques and calibration methods are investigated to standardize the thermographic method for use in the field. Along with the inspections of test standards structural hardware, support hardware is designed and fabricated to aid in the thermographic process. Also, a standard operating procedure is developed for performing inspections with the Bales Thermal Image Processor (TIP). Inspections are performed on a broad range of structural composites. These materials include various graphite/epoxies, graphite/cyanide-ester, graphite/silicon-carbide, graphite phenolic and Keviar/epoxy. Also metal honeycomb (titanium and aluminum faceplates over an aluminum honeycomb core) structures are investigated. Various structural shapes are investigated and the thickness of the structures vary from as few as 3 plies to as many as 80 plies. Special emphasis is placed on characterizing defects in attachment holes and bondlines, in addition to those resulting from impact damage and the inclusion of foreign matter. Image processing through statistical analysis and digital filtering is investigated to enhance the quality and quantify the NDE thermal images when necessary.

  8. Study Methods to Standardize Thermography NDE

    NASA Technical Reports Server (NTRS)

    Walker, James L.; Workman, Gary L.

    1998-01-01

    The purpose of this work is to develop thermographic inspection methods and standards for use in evaluating structural composites and aerospace hardware. Qualification techniques and calibration methods are investigated to standardize the thermographic method for use in the field. Along with the inspections of test standards structural hardware, support hardware is designed and fabricated to aid in the thermographic process. Also, a standard operating procedure is developed for performing inspections with the Bales Thermal Image Processor (TIP). Inspections are performed on a broad range of structural composites. These materials include graphite/epoxies, graphite/cyanide-ester, graphite/silicon-carbide, graphite phenolic and Kevlar/epoxy. Also metal honeycomb (titanium and aluminum faceplates over an aluminum honeycomb core) structures are investigated. Various structural shapes are investigated and the thickness of the structures vary from as few as 3 plies to as many as 80 plies. Special emphasis is placed on characterizing defects in attachment holes and bondlines, in addition to those resulting from impact damage and the inclusion of foreign matter. Image processing through statistical analysis and digital filtering is investigated to enhance the quality and quantify the NDE thermal images when necessary.

  9. Developing NDE Techniques for Large Cryogenic Tanks

    NASA Technical Reports Server (NTRS)

    Parker, Don; Starr, Stan; Arens, Ellen

    2011-01-01

    The Shuttle Program requires very large cryogenic ground storage tanks in which to store liquid oxygen and hydrogen. The existing Pads A and B Launch Complex-39 tanks, which will be passed onto future launch programs, are 45 years old and have received minimal refurbishment and only external inspections over the years. The majority of the structure is inaccessible without a full system drain of cryogenic liquid and granular insulation in the annular region. It was previously thought that there was a limit to the number of temperature cycles that the tanks could handle due to possible insulation compaction before undergoing a costly and time consuming complete overhaul; therefore the tanks were not drained and performance issues with these tanks, specifically the Pad B liquid hydrogen tank, were accepted. There is a needind an opportunity, as the Shuttle program ends and work to upgrade the launch pads progresses, to develop innovative non-destructive evaluation (NDE) techniques to analyze the current tanks. Techniques are desired that can aid in determining the extent of refurbishment required to keep the tanks in service for another 20+ years. A nondestructive technique would also be a significant aid in acceptance testing of new and refurbished tanks, saving significant time and money, if corrective actions can be taken before cryogen is introduced to the systems.

  10. Quantitative NDE of Composite Structures at NASA

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott; Leckey, Cara A. C.; Howell, Patricia A.; Johnston, Patrick H.; Burke, Eric R.; Zalameda, Joseph N.; Winfree, William P.; Seebo, Jeffery P.

    2015-01-01

    The use of composite materials continues to increase in the aerospace community due to the potential benefits of reduced weight, increased strength, and manufacturability. Ongoing work at NASA involves the use of the large-scale composite structures for spacecraft (payload shrouds, cryotanks, crew modules, etc). NASA is also working to enable the use and certification of composites in aircraft structures through the Advanced Composites Project (ACP). The rapid, in situ characterization of a wide range of the composite materials and structures has become a critical concern for the industry. In many applications it is necessary to monitor changes in these materials over a long time. The quantitative characterization of composite defects such as fiber waviness, reduced bond strength, delamination damage, and microcracking are of particular interest. The research approaches of NASA's Nondestructive Evaluation Sciences Branch include investigation of conventional, guided wave, and phase sensitive ultrasonic methods, infrared thermography and x-ray computed tomography techniques. The use of simulation tools for optimizing and developing these methods is also an active area of research. This paper will focus on current research activities related to large area NDE for rapidly characterizing aerospace composites.

  11. A Destructive Validation of NDE Responses of Service-Induced PWSCC Found in North Anna 2 Control Rod Drive Nozzle 31

    SciTech Connect

    Cumblidge, Stephen E.; Doctor, Steven R.; Schuster, George J.; Harris, Robert V.; Crawford, Susan L.; Seffens, Rob J.; Toloczko, Mychailo B.; Bruemmer, Stephen M.; Moyer, C.

    2009-07-01

    Studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington focused on assessing the effectiveness of nondestructive examination (NDE) techniques for inspecting control rod drive mechanism (CRDM) nozzles and J-groove weldments. The primary objective of this work is to provide information to the United States Nuclear Regulatory Commission (NRC) on the effectiveness of NDE methods as related to the in-service inspection of CRDM nozzles and J-groove weldments, and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies.

  12. Summary of NDE of additive manufacturing efforts in NASA

    NASA Astrophysics Data System (ADS)

    Waller, Jess M.; Saulsberry, Regor L.; Parker, Bradford H.; Hodges, Kenneth L.; Burke, Eric R.; Taminger, Karen M.

    2015-03-01

    One of the major obstacles slowing the acceptance of parts made by additive manufacturing (AM) in NASA applications is the lack of a broadly accepted materials and process quality systems; and more specifically, the lack of adequate nondestructive evaluation (NDE) processes integrated into AM. Matching voluntary consensus standards are also needed to control the consistency of input materials, process equipment, process methods, finished part properties, and how those properties are characterized. As for nondestructive characterization, procedures are needed to interrogate features unique to parts made by AM, such as fine-scale porosity, deeply embedded flaws, complex part geometry, and intricate internal features. The NDE methods developed must be tailored to meet materials, design and test requirements encountered throughout the part life cycle, whether during process optimization, real-time process monitoring, finished part qualification and certification (especially of flight hardware), or in situ health monitoring. Restated, individualized process/product-specific NDE methods are needed to satisfy NASA's various quality assurance requirements. To date, only limited data have been acquired by NASA on parts made by AM. This paper summarizes the NASA AM effort, highlights available NDE data, and outlines the approach NASA is taking to apply NDE to its various AM efforts.

  13. NDE activities and technology transfer at Sandia National Laboratories

    SciTech Connect

    Shurtleff, W.W.

    1993-12-31

    The NDE, Photometrics, and Optical Data Reduction Department at Sandia National Laboratories in New Mexico (S provides nondestructive evaluation (NDE) support for all phases of research and development at Sandia. Present facilities and personnel provide radiography, acoustic monitoring, ultrasonic scanning, computed tomography, shearography/ESPI, infrared imaging, high speed and ultra-high speed photometrics, and image processing. Although the department includes photometrics and optical data reduction as well as NDE, I will refer to the NDE department from now on for simplicity. The NDE department has worked on technology transfer to organizations inside and outside the weapons complex. This work has been performed in all the Sandia business sectors: Defense Programs, Energy and Environment, and Work for Others. The technology transfer has been in the form of testing for product improvement such as validation of aircraft inspection equipment, consultation such as detecting lathe bearing slip for a major machine tool manufacturer, and products such as an acoustic sand detector for the oil and gas industry.

  14. Best practices for evaluating the capability of nondestructive evaluation (NDE) and structural health monitoring (SHM) techniques for damage characterization

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    A comprehensive approach to NDE and SHM characterization error (CE) evaluation is presented that follows the framework of the `ahat-versus-a' regression analysis for POD assessment. Characterization capability evaluation is typically more complex with respect to current POD evaluations and thus requires engineering and statistical expertise in the model-building process to ensure all key effects and interactions are addressed. Justifying the statistical model choice with underlying assumptions is key. Several sizing case studies are presented with detailed evaluations of the most appropriate statistical model for each data set. The use of a model-assisted approach is introduced to help assess the reliability of NDE and SHM characterization capability under a wide range of part, environmental and damage conditions. Best practices of using models are presented for both an eddy current NDE sizing and vibration-based SHM case studies. The results of these studies highlight the general protocol feasibility, emphasize the importance of evaluating key application characteristics prior to the study, and demonstrate an approach to quantify the role of varying SHM sensor durability and environmental conditions on characterization performance.

  15. An Examination of Test-Retest, Alternate Form Reliability, and Generalizability Theory Study of the easyCBM Reading Assessments: Grade 1. Technical Report #1216

    ERIC Educational Resources Information Center

    Anderson, Daniel; Park, Jasmine, Bitnara; Lai, Cheng-Fei; Alonzo, Julie; Tindal, Gerald

    2012-01-01

    This technical report is one in a series of five describing the reliability (test/retest/and alternate form) and G-Theory/D-Study research on the easy CBM reading measures, grades 1-5. Data were gathered in the spring 2011 from a convenience sample of students nested within classrooms at a medium-sized school district in the Pacific Northwest. Due…

  16. The reliability of a 10-test package for patients with prolonged back and neck pain: could an examiner without formal medical education be used without loss of quality? A methodological study

    PubMed Central

    Lindell, Odd; Eriksson, Lars; Strender, Lars-Erik

    2007-01-01

    Background In the rehabilitation of patients with prolonged back and neck pain, the physical impairment should be assessed. Previous research has exclusively engaged medically educated examiners, mostly physiotherapists. However, less biased evaluations of efforts at rehabilitation might be achieved by personnel standing outside the treatment work itself. Therefore, if medically untrained examiners could be used without cost to the quality, this might produce a better evaluation at defensible cost and could also be useful in a research context. The aim of this study was to answer the question: given a 10-test package for patients with prolonged back and neck pain, could an examiner without formal medical education be used without loss of quality? Five of the ten tests required the examiner to keep a firm hold against the foundation of those parts of the participant's body that were not supposed to move during the test. Methods Examination by an experienced physiotherapist (A) in performing the package was compared with that by a research assistant (B) without formal medical education. The reliability, including inter- and intra-rater reliability, was assessed. In the inter-rater reliability study, 50 participants (30 patients + 20 healthy subjects) were tested once each by A and B. In the intra-rater reliability study, the 20 healthy subjects were tested twice by A or B. One-way ANOVA intra-class-correlation coefficient (ICC) was calculated and its possible systematic error was determined using a t-test. Results All five tests that required no manual fixation had acceptable reliability (ICC > .60 and no indication of systematic error). Only one of the five tests that required fixation had acceptable reliability. The difference (five vs. one) was significant (p = .01). Conclusion In a 10-test package for patients with prolonged back and neck pain, an examiner without formal medical education could be used without loss of quality, at least for the five tests

  17. NASA NDE Applications for Mobile MEMS Devices and Sensors

    NASA Technical Reports Server (NTRS)

    Wilson, William C.; Atkinson, Gary M.; Barclay, R. O.

    2008-01-01

    NASA would like new devices and sensors for performing nondestructive evaluation (NDE) of aerospace vehicles. These devices must be small in size/volume, mass, and power consumption. The devices must be autonomous and mobile so they can access the internal structures of aircraft and spacecraft and adequately monitor the structural health of these craft. The platforms must be mobile in order to transport NDE sensors for evaluating structural integrity and determining whether further investigations will be required. Microelectromechanical systems (MEMS) technology is crucial to the development of the mobile platforms and sensor systems. This paper presents NASA s needs for micro mobile platforms and MEMS sensors that will enable NDE to be performed on aerospace vehicles.

  18. Summary of NDE of Additive Manufacturing Efforts in NASA

    NASA Technical Reports Server (NTRS)

    Waller, Jess; Saulsberry, Regor; Parker, Bradford; Hodges, Kenneth; Burke, Eric; Taminger, Karen

    2014-01-01

    (1) General Rationale for Additive Manufacturing (AM): (a) Operate under a 'design-to-constraint' paradigm, make parts too complicated to fabricate otherwise, (b) Reduce weight by 20 percent with monolithic parts, (c) Reduce waste (green manufacturing), (e) Eliminate reliance on Original Equipment Manufacturers for critical spares, and (f) Extend life of in-service parts by innovative repair methods; (2) NASA OSMA NDE of AM State-of-the-Discipline Report; (3) Overview of NASA AM Efforts at Various Centers: (a) Analytical Tools, (b) Ground-Based Fabrication (c) Space-Based Fabrication; and (d) Center Activity Summaries; (4) Overview of NASA NDE data to date on AM parts; and (5) Gap Analysis/Recommendations for NDE of AM.

  19. An Integrated NDE and FEM Characterization of Composite Rotors

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    A structural assessment by integrating finite-element methods (FEM) and a nondestructive evaluation (NDE) of two flywheel rotor assemblies is presented. Composite rotor A is pancake like with a solid hub design, and composite rotor B is cylindrical with a hollow hub design. Detailed analyses under combined centrifugal and interference-fit loading are performed. Two- and three-dimensional stress analyses and two-dimensional fracture mechanics analyses are conducted. A comparison of the structural analysis results obtained with those extracted via NDE findings is reported. Contact effects due to press-fit conditions are evaluated. Stress results generated from the finite-element analyses were corroborated with the analytical solution. Cracks due to rotational loading up to 49 000 rpm for rotor A and 34 000 rpm for rotor B were successfully imaged with NDE and predicted with FEM and fracture mechanics analyses. A procedure that extends current structural analysis to a life prediction tool is also defined.

  20. Predicting software reliability

    NASA Technical Reports Server (NTRS)

    Littlewood, B.

    1989-01-01

    A detailed look is given to software reliability techniques. A conceptual model of the failure process is examined, and some software reliability growth models are discussed. Problems for which no current solutions exist are addressed, emphasizing the very difficult problem of safety-critical systems for which the reliability requirements can be enormously demanding.

  1. An Examination of Test-Retest, Alternate Form Reliability, and Generalizability Theory Study of the easyCBM Passage Reading Fluency Assessments: Grade 4. Technical Report #1219

    ERIC Educational Resources Information Center

    Park, Bitnara Jasmine; Anderson, Daniel; Alonzo, Julie; Lai, Cheng-Fei; Tindal, Gerald

    2012-01-01

    This technical report is one in a series of five describing the reliability (test/retest and alternate form) and G-Theory/D-Study research on the easyCBM reading measures, grades 1-5. Data were gathered in the spring of 2011 from a convenience sample of students nested within classrooms at a medium-sized school district in the Pacific Northwest.…

  2. An Examination of Test-Retest, Alternate Form Reliability, and Generalizability Theory Study of the easyCBM Reading Assessments: Grade 5. Technical Report #1220

    ERIC Educational Resources Information Center

    Lai, Cheng-Fei; Park, Bitnara Jasmine; Anderson, Daniel; Alonzo, Julie; Tindal, Gerald

    2012-01-01

    This technical report is one in a series of five describing the reliability (test/retest and alternate form) and G-Theory/D-Study research on the easyCBM reading measures, grades 1-5. Data were gathered in the spring of 2011 from a convenience sample of students nested within classrooms at a medium-sized school district in the Pacific Northwest.…

  3. An Examination of Test-Retest, Alternate Form Reliability, and Generalizability Theory Study of the easyCBM Reading Assessments: Grade 2. Technical Report #1217

    ERIC Educational Resources Information Center

    Anderson, Daniel; Lai, Cheg-Fei; Park, Bitnara Jasmine; Alonzo, Julie; Tindal, Gerald

    2012-01-01

    This technical report is one in a series of five describing the reliability (test/retest an alternate form) and G-Theory/D-Study on the easyCBM reading measures, grades 1-5. Data were gathered in the spring of 2011 from the convenience sample of students nested within classrooms at a medium-sized school district in the Pacific Northwest. Due to…

  4. Eddy current NDE performance demonstrations using simulation tools

    NASA Astrophysics Data System (ADS)

    Maurice, L.; Costan, V.; Guillot, E.; Thomas, P.

    2013-01-01

    To carry out performance demonstrations of the Eddy-Current NDE processes applied on French nuclear power plants, EDF studies the possibility of using simulation tools as an alternative to measurements on steam generator tube mocks-up. This paper focuses on the strategy led by EDF to assess and use code_Carmel3D and Civa, on the case of Eddy-Current NDE on wears problem which may appear in the U-shape region of steam generator tubes due to the rubbing of anti-vibration bars.

  5. Experimental techniques in ultrasonics for NDE and material characterization

    NASA Astrophysics Data System (ADS)

    Tittmann, B. R.

    A development status evaluation is presented for ultrasonics NDE characterization of aerospace alloys and composites in such application as the Space Shuttle, Space Station Freedom, and hypersonic aircraft. The use of such NDE techniques extends to composite-cure monitoring, postmanufacturing quality assurance, and in-space service inspection of such materials as graphite/epoxy, Ti alloys, and Al honeycomb. Attention is here given to the spectroscopy of elastically scattered wave pulses from flaws, the acoustical imaging of flaws in honeycomb structures, and laser-based ultrasonics for the noncontact inspection of composite structures.

  6. Preview of the NASA NNWG NDE Sample Preparation Handbook

    NASA Technical Reports Server (NTRS)

    2010-01-01

    This viewgraph presents a step-by-step how-to fabrication documentation of every kind of sample that is fabricated for MSFC by UA Huntsville, including photos and illustrations. The tabulation of what kind of samples are being fabricated for what NDE method, detailed instructions/documentation of the inclusion/creation of defects, detailed specifications for materials, processes, and equipment, case histories and/or experiences with the different fabrication methods and defect inclusion techniques, discussion of pitfalls and difficulties associated with sample fabrication and defect inclusion techniques, and a discussion of why certain fabrication techniques are needed as related to the specific NDE methods are included in this presentation.

  7. Eddy current NDE performance demonstrations using simulation tools

    SciTech Connect

    Maurice, L.; Costan, V.; Guillot, E.; Thomas, P.

    2013-01-25

    To carry out performance demonstrations of the Eddy-Current NDE processes applied on French nuclear power plants, EDF studies the possibility of using simulation tools as an alternative to measurements on steam generator tube mocks-up. This paper focuses on the strategy led by EDF to assess and use code{sub C}armel3D and Civa, on the case of Eddy-Current NDE on wears problem which may appear in the U-shape region of steam generator tubes due to the rubbing of anti-vibration bars.

  8. Flight-vehicle materials, structures, and dynamics - Assessment and future directions. Vol. 4 - Tribological materials and NDE

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L. (Editor); Achenbach, J. D. (Editor)

    1993-01-01

    The present volume on tribological materials and NDE discusses liquid lubricants for advanced aircraft engines, a liquid lubricant for space applications, solid lubricants for aeronautics, and thin solid-lubricant films in space. Attention is given to the science and technology of NDE, tools for an NDE engineering base, experimental techniques in ultrasonics for NDE and material characterization, and laser ultrasonics. Topics addressed include thermal methods of NDE and quality control, digital radiography in the aerospace industry, materials characterization by ultrasonic methods, and NDE of ceramics and ceramic composites. Also discussed are smart materials and structures, intelligent processing of materials, implementation of NDE technology on flight structures, and solid-state weld evaluation.

  9. Results of NDE Technique Evaluation of Clad Hydrides

    SciTech Connect

    Dennis C. Kunerth

    2014-09-01

    This report fulfills the M4 milestone, M4FT-14IN0805023, Results of NDE Technique Evaluation of Clad Hydrides, under Work Package Number FT-14IN080502. During service, zirconium alloy fuel cladding will degrade via corrosion/oxidation. Hydrogen, a byproduct of the oxidation process, will be absorbed into the cladding and eventually form hydrides due to low hydrogen solubility limits. The hydride phase is detrimental to the mechanical properties of the cladding and therefore it is important to be able to detect and characterize the presence of this constituent within the cladding. Presently, hydrides are evaluated using destructive examination. If nondestructive evaluation techniques can be used to detect and characterize the hydrides, the potential exists to significantly increase test sample coverage while reducing evaluation time and cost. To demonstrate the viability this approach, an initial evaluation of eddy current and ultrasonic techniques were performed to demonstrate the basic ability to these techniques to detect hydrides or their effects on the microstructure. Conventional continuous wave eddy current techniques were applied to zirconium based cladding test samples thermally processed with hydrogen gas to promote the absorption of hydrogen and subsequent formation of hydrides. The results of the evaluation demonstrate that eddy current inspection approaches have the potential to detect both the physical damage induced by hydrides, e.g. blisters and cracking, as well as the combined effects of absorbed hydrogen and hydride precipitates on the electrical properties of the zirconium alloy. Similarly, measurements of ultrasonic wave velocities indicate changes in the elastic properties resulting from the combined effects of absorbed hydrogen and hydride precipitates as well as changes in geometry in regions of severe degradation. However, for both approaches, the signal responses intended to make the desired measurement incorporate a number of contributing

  10. Miniaturized hand held microwave interference scanning system for NDE of dielectric armor and armor systems

    SciTech Connect

    Schmidt, Karl F.; Little, Jack R.; Ellingson, William A.; Meitzler, Thomas J.; Green, William

    2011-06-23

    Inspection of ceramic-based armor has advanced through development of a microwave-based, portable, non-contact NDE system. Recently, this system was miniaturized and made wireless for maximum utility in field applications. The electronic components and functionality of the laboratory system are retained, with alternative means of position input for creation of scan images. Validation of the detection capability was recently demonstrated using specially fabricated surrogates and ballistic impact-damaged specimens. The microwave data results have been compared to data from laboratory-based microwave interferometry systems and digital x-ray imaging. The microwave interference scanning has been shown to reliably detect cracks, laminar features and material property variations. The authors present details of the system operation, descriptions of the test samples used and recent results obtained.

  11. Extending the use of the Web-based HIV Testing Belief Inventory to students attending historically Black colleges and universities: an examination of reliability and validity.

    PubMed

    Hou, Su-I

    2009-02-01

    This study sought to extend the use of a Web-based HIV Testing Belief Inventory (wHITBI), developed and validated in a majority White university in the southeastern United States, to students attending historically Black colleges and universities (HBCUs). The 19-item wHITBI was reviewed by experts to qualitatively assess its construct validity, clarity, relevancy, and comprehensiveness to HBCU students. Participants were recruited from 15 HBCUs (valid N = 372). Mean age was 20.5 years (SD = 2.4), 80% were females, 92% were heterosexual-oriented, and 58% had prior HIV test(s). Reliability coefficients revealed satisfactory internal consistencies (Cronbach's alphas: .58 approximately .85). Confirmatory factor analysis showed that items were loaded consistently with the four constructs: perceived benefits, concerns of HIV risk, stigma, and testing availability/accessibility. Data indicated good model fits (RMSEA = .06; CFI = .93; IFI = .93; RMS = .07), with all items loaded significantly. Findings showed that the psychometrics of wHITBI appears to maintain its integrity in this sample with satisfactory reliability coefficients and validities. PMID:19243233

  12. Sparse signal representation and its applications in ultrasonic NDE.

    PubMed

    Zhang, Guang-Ming; Zhang, Cheng-Zhong; Harvey, David M

    2012-03-01

    Many sparse signal representation (SSR) algorithms have been developed in the past decade. The advantages of SSR such as compact representations and super resolution lead to the state of the art performance of SSR for processing ultrasonic non-destructive evaluation (NDE) signals. Choosing a suitable SSR algorithm and designing an appropriate overcomplete dictionary is a key for success. After a brief review of sparse signal representation methods and the design of overcomplete dictionaries, this paper addresses the recent accomplishments of SSR for processing ultrasonic NDE signals. The advantages and limitations of SSR algorithms and various overcomplete dictionaries widely-used in ultrasonic NDE applications are explored in depth. Their performance improvement compared to conventional signal processing methods in many applications such as ultrasonic flaw detection and noise suppression, echo separation and echo estimation, and ultrasonic imaging is investigated. The challenging issues met in practical ultrasonic NDE applications for example the design of a good dictionary are discussed. Representative experimental results are presented for demonstration. PMID:22040650

  13. A CAD Approach to Integrating NDE With Finite Element

    NASA Technical Reports Server (NTRS)

    Abdul-Aziz, Ali; Downey, James; Ghosn, Louis J.; Baaklini, George Y.

    2004-01-01

    Nondestructive evaluation (NDE) is one of several technologies applied at NASA Glenn Research Center to determine atypical deformities, cracks, and other anomalies experienced by structural components. NDE consists of applying high-quality imaging techniques (such as x-ray imaging and computed tomography (CT)) to discover hidden manufactured flaws in a structure. Efforts are in progress to integrate NDE with the finite element (FE) computational method to perform detailed structural analysis of a given component. This report presents the core outlines for an in-house technical procedure that incorporates this combined NDE-FE interrelation. An example is presented to demonstrate the applicability of this analytical procedure. FE analysis of a test specimen is performed, and the resulting von Mises stresses and the stress concentrations near the anomalies are observed, which indicates the fidelity of the procedure. Additional information elaborating on the steps needed to perform such an analysis is clearly presented in the form of mini step-by-step guidelines.

  14. NDE Elastic Properties of Fiber-Reinforced Composite Materials

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Y.

    1995-01-01

    Fiber-reinforced composites are increasingly replacing metallic alloys as structural materials for primary components of fracture-critical structures. This trend is a result of the growing understanding of material behavior and recognition of the desirable properties of composites. A research program was conducted on NDE methods for determining the elastic properties of composites.

  15. NDE for Material Characterization in Aeronautic and Space Applications

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    This paper describes selected nondestructive evaluation (NDE) approaches that were developed or tailored at the NASA Glenn Research Center for characterizing advanced material systems. The emphasis is on high-temperature aerospace propulsion applications. The material systems include monolithic ceramics, superalloys, and high temperature composites. In the aeronautic area, the highlights are cooled ceramic plate structures for turbine applications, F-TiAl blade materials for low-pressure turbines, thermoelastic stress analysis (TSA) for residual stress measurements in titanium based and nickel based engine materials, and acousto ultrasonics (AU) for creep damage assessment in nickel-based alloys. In the space area, examples consist 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 (ISS). The role of NDE in solving manufacturing problems, the effect of defects on structural behavior, and the use of NDE-based finite element modeling are discussed. NDE technology needs for improved microelectronic and mechanical systems as well as health monitoring of micro-materials and components are briefly discussed.

  16. Platform for Post-Processing Waveform-Based NDE

    NASA Technical Reports Server (NTRS)

    Roth, Don J.

    2010-01-01

    Signal- and image-processing methods are commonly needed to extract information from the waves, improve resolution of, and highlight defects in an image. Since some similarity exists for all waveform-based nondestructive evaluation (NDE) methods, it would seem that a common software platform containing multiple signal- and image-processing techniques to process the waveforms and images makes sense where multiple techniques, scientists, engineers, and organizations are involved. NDE Wave & Image Processor Version 2.0 software provides a single, integrated signal- and image-processing and analysis environment for total NDE data processing and analysis. It brings some of the most useful algorithms developed for NDE over the past 20 years into a commercial-grade product. The software can import signal/spectroscopic data, image data, and image series data. This software offers the user hundreds of basic and advanced signal- and image-processing capabilities including esoteric 1D and 2D wavelet-based de-noising, de-trending, and filtering. Batch processing is included for signal- and image-processing capability so that an optimized sequence of processing operations can be applied to entire folders of signals, spectra, and images. Additionally, an extensive interactive model-based curve-fitting facility has been included to allow fitting of spectroscopy data such as from Raman spectroscopy. An extensive joint-time frequency module is included for analysis of non-stationary or transient data such as that from acoustic emission, vibration, or earthquake data.

  17. NASA OSMA NDE Program Additive Manufacturing Foundational Effort

    NASA Technical Reports Server (NTRS)

    Waller, Jess; Walker, James; Burke, Eric; Wells, Douglas

    2016-01-01

    NASA is providing key leadership in an international effort linking NASA and non-NASA resources to speed adoption of additive manufacturing (AM) to meet NASA's mission goals. Participants include industry, NASA's space partners, other government agencies, standards organizations and academia. Nondestructive Evaluation (NDE) is identified as a universal need for all aspects of additive manufacturing.

  18. Advanced NDE techniques for quantitative characterization of aircraft

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S.; Winfree, William P.

    1990-01-01

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

  19. Rocket center Peenemünde — Personal memories

    NASA Astrophysics Data System (ADS)

    Dannenberg, Konrad; Stuhlinger, Ernst

    Von Braun built his first rockets as a young teenager. At 14, he started making plans for rockets for human travel to the Moon and Mars. The German Army began a rocket program in 1929. Two years later, Colonel (later General) Becker contacted von Braun who experimented with rockets in Berlin, gave him a contract in 1932, and, jointly with the Air Force, in 1936 built the rocket center Peenemünde where von Braun and his team developed the A-4 (V-2) rocket under Army auspices, while the Air Force developed the V-1 (buzz bomb), wire-guided bombs, and rocket planes. Albert Speer, impressed by the work of the rocketeers, allowed a modest growth of the Peenemünde project; this brought Dannenberg to the von Braun team in 1940. Hitler did not believe in rockets; he ignored the A-4 project until 1942 when he began to support it, expecting that it could turn the fortunes of war for him. He drastically increased the Peenemünde work force and allowed the transfer of soldiers from the front to Peenemünde; that was when Stuhlinger, in 1943, came to Peenemünde as a Pfc.-Ph.D. Later that year, Himmler wrenched the authority over A-4 production out of the Army's hands, put it under his command, and forced production of the immature rocket at Mittelwerk, and its military deployment against targets in France, Belgium, and England. Throughout the development of the A-4 rocket, von Braun was the undisputed leader of the project. Although still immature by the end of the war, the A-4 had proceeded to a status which made it the first successful long-range precision rocket, the prototype for a large number of military rockets built by numerous nations after the war, and for space rockets that launched satellites and traveled to the Moon and the planets.

  20. Replacing methyl chloroform for cleaning turbine generator components and NDE applications

    SciTech Connect

    Bailey, K.P.; O'Shanka, J.J.; Corley, T.J. . Power Generation Business Unit); Sadhir, R.K. )

    1993-08-01

    Industrial applications of methyl chloroform (1,1,1-trichloroethane) have proven to be a significant concern to the environment. As a chlorofluorocarbon (CFC), the chemical is classified by the Environmental Protection Agency as an ozone-layer-depleting substance (OLDS). CFCs are effective cleaners of organic-based materials (oils, greases, cutting fluids, etc.). The Westinghouse Power Generation Business Unit (PGBU) has taken a proactive approach to this problem and instituted two programs in 1991 and 1992 to eliminate their consumption of CFCs. The scope of the first program was to establish an alternate cleaner for the removal of oil on generator stator windings. The second program built on the work of the first program, extending the scope to include general purpose cleaning of various contaminants prior to and at the completion of nondestructive examinations (NDE). The article that follows details the methodology, results, discussions, and conclusions of the second program and the data extrapolated from the first program. The specific NDE qualification requirements are highlighted in the methodology section.

  1. Water content and its effect on ultrasound propagation in concrete--the possibility of NDE

    PubMed

    Ohdaira; Masuzawa

    2000-03-01

    It is known that water content or moisture affects the strength of concrete. The purpose of this study is to examine the possibility of the NDE of concrete from a knowledge of the relationship between water content and ultrasonic propagation in concrete. The results of measurements made on the ultrasound velocity and the frequency component on ultrasonic propagation as a function of the water content in concrete are reported. Test pieces of concrete made from common materials were made for the fundamental studies. The test piece dimensions were 10 cm in diameter and 20 cm in length. Test pieces were immersed in water for about 50 days to saturate them. To measure the effect of different water contents, test pieces were put in a drying chamber to change the amount of water between measurements. This procedure was repeated until the concrete was completely dried and the weight no longer changed. Water contents were defined as weight percentage to full dried state. Thus water content could be changed from 8% to 0%. Using the pulse transmission method, ultrasonic propagation in the frequency range 20 to 100 kHz was measured as a function of water content. The sound velocity varied gradually from 3000 m/s to 4500 m/s according to the water content. The frequency of maximum transmission also depended on the water content in this frequency range. It is considered that the ultrasonic NDE of concrete strength is feasible. PMID:10829724

  2. Photoelastic measurements of residual stresses for NDE

    NASA Technical Reports Server (NTRS)

    Redner, Alex S.

    1988-01-01

    Photoelastic measurements of residual strains are used extensively in the QC and inspection of transparent materials. A new method of measurements, based on Spectral Contents Analysis, is described in this paper. The method uses a personal computer for photoelastic data acquisition, eliminating personal skill and subjectivity. the new tool should make the measurements of residual strains for QC simpler and more reliable.

  3. Processing and Probability Analysis of Pulsed Terahertz NDE of Corrosion under Shuttle Tile Data

    NASA Technical Reports Server (NTRS)

    Anastasi, Robert F.; Madaras, Eric I.; Seebo, Jeffrey P.; Ely, Thomas M.

    2009-01-01

    This paper examines data processing and probability analysis of pulsed terahertz NDE scans of corrosion defects under a Shuttle tile. Pulsed terahertz data collected from an aluminum plate with fabricated corrosion defects and covered with a Shuttle tile is presented. The corrosion defects imaged were fabricated by electrochemically etching areas of various diameter and depth in the plate. In this work, the aluminum plate echo signal is located in the terahertz time-of-flight data and a threshold is applied to produce a binary image of sample features. Feature location and area are examined and identified as corrosion through comparison with the known defect layout. The results are tabulated with hit, miss, or false call information for a probability of detection analysis that is used to identify an optimal processing threshold.

  4. Nondestructive assay and nondestructive examination of remote-handled transuranic waste at the ORNL waste handling and packaging plant

    SciTech Connect

    Schultz, F.J.; Caldwell, J.T.; Pajarito Scientific Corp. )

    1989-01-01

    The purpose of this investigation is to examine the use of an electron linear accelerator (LINAC) in the performance of nondestructive assay (NDA) and nondestructive examination (NDE) measurements of remote-handled transuranic wastes. The system will be used to perform waste characterization and certification activities at the Oak Ridge National Laboratory's proposed Waste Handling and Packaging Plant. The NDA and NDE technologies which were developed for contact-handled wastes are inadequate to perform such measurements on high gamma and neutron dose-rate wastes. A single LINAC will provide the interrogating fluxes required for both NDA and NDE measurements of the wastes. 11 refs., 6 figs.

  5. Recent Improvements in Display and Analysis of Nde Data at NASA

    NASA Astrophysics Data System (ADS)

    Roth, D. J.; Rauser, R. W.; Abdul-Aziz, A.; Cotton, R.; Burke, E.; Zhang, S.; Marsh, M.; Davis, B. A.; Studor, G. F.

    2011-06-01

    This talk reviews several recent NDE data visualization and analysis improvements implemented at NASA Glenn Research Center. Examples will be shown in the areas of X-ray computed tomography and waveform-based NDE. Emphasis is on methods that are most useful not only for the NDE professional analyzing the data but also for sharing of the data with customers such as material processors, testers, and modelers who need to use the data for various engineering decisions.

  6. Reliability and validity of the modified child and adolescent physical activity and nutrition survey (CAPANS-C) questionnaire examining potential correlates of physical activity participation among Chinese-Australian youth

    PubMed Central

    2014-01-01

    Background To date, few questionnaires examining psychosocial influences of physical activity (PA) participation have been psychometrically tested among Culturally and Linguistically Diverse (CALD) youth. An understanding of these influences may help explain the observed differences in PA among CALD youth. Therefore, this study examined the reliability and predictive validity of a brief self-report questionnaire examining potential psychological and social correlates of physical activity among a sample of Chinese-Australian youth. Methods Two Chinese-weekend cultural schools from eastern metropolitan Melbourne consented to participate in this study. In total, 505 students aged 11 to 16 years were eligible for inclusion in the present study, and of these, 106 students agreed to participate (21% response rate). Participants completed at 37-item self-report questionnaire examining perceived psychological and social influences on physical activity participation twice, with a test–retest interval of 7 days. Predictive validity, internal consistency and test–retest reliability were evaluated using exploratory factor analyses, Cronbach’s α coefficient, and the intraclass correlation coefficient (ICC) respectively. Predictive validity was assessed by correlating responses against duration spent in self-reported moderate-to-vigorous physical activity (MVPA). Results The exploratory factor analysis revealed a nine factor structure, with the majority of factors exhibiting high internal consistency (α ≥ 0.6). In addition, four of the nine factors had an ICC ≥ 0.6. Spearman rank-order correlations coefficients between the nine factors and self-reported minutes spent in MVPA ranged from -0.5 to 0.3 for all participants. Conclusion This is the first study to examine the psychometric properties of a potential psychological and social correlates questionnaire among Chinese-Australian youth. The questionnaire was found to provide reliable estimates on a range

  7. System for NDE of thermal spray coating bonds

    SciTech Connect

    Green, D.R.; Wandling, C.R.; Gatto, F.B.; Rogers, F.S.

    1984-09-01

    A nondestructive testing system that is especially well suited to NDE of bonds between coatings and substrates has been developed. It injects heat into the test specimen surface from a hot gas pulse and detects and other coating problems by means of an emissivity independent infrared scanning method. This method is very practical and has been proven in numerous demonstrations. It is the only method known by the authors to be applicable to such a wide variety of coatings. Qualitative correlation between bond strength and scan results from the system was demonstrated on one small group of test specimens. Due to its emissivity independence, the method yields results that are, in many cases, far superior to other infrared-thermal NDE methods. It can be applied to coatings having tough surfaces, and no physical contact with the test specimen is required.

  8. Mechanics aspects of NDE by sound and ultrasound

    NASA Technical Reports Server (NTRS)

    Fu, L. S.

    1982-01-01

    Nondestructive evaluation (NDE) is considered as a means to detect the energy release mechanism of defects and the interaction of microstructures within materials with sound waves and/or ultrasonic waves. Ultrasonic inspection involves the frequency range 20 kHz-1 GHz with amplitudes depending on the sensitivity of the test instrumentation. Pulse echo systems are most frequently used in NDE. Information is extracted from the signals through measurements of the signal velocity, attenuation, the acoustic emission when stress is applied, and calculation of the acoustoelastic coefficients. Fracture properties, tensile and shear strengths, the interlaminar shear strength, the cohesive strength, yield and impact strengths, the hardness, and the residual stress can be assayed by ultrasonic methods. Finally, attention is given to analytical treatment of the derived data, with mention given to transition matrix, integral equation, and eigenstrain approaches.

  9. Determining material properties of metal-matrix composites by NDE

    NASA Astrophysics Data System (ADS)

    Liaw, P. K.; Shannon, R. E.; Clark, W. G.; Harrigan, W. C.; Jeong, H.; Hsu, D. K.

    1992-10-01

    Nondestructive evaluation (NDE) is a promising means of studying silicon carbide particulate (SiCp)-reinforced aluminum metal-matrix composite (MMC) products at various processing stages. Eddy current techniques are effective in characterizing alloy powders and in evaluating the percentage of reinforcement in Al/SiCp powder mixtures. Ultrasonic methods can be used to identify SiCp clusters in large-scale, powder metallurgy processed MMC billets, while eddy current techniques can detect near-surface density variations. Ultrasonic techniques can also be used to determine the anisotropic stiffness constants of composite extrusions; the measured moduli are in good agreement with those determined by tensile testing. These results suggest that NDE can be used to provide on-line, closed-loop control of MMC manufacturing.

  10. Nondestructive examination technologies for inspection of radioactive waste storage tanks

    SciTech Connect

    Anderson, M.T.; Kunerth, D.C.; Davidson, J.R.

    1995-08-01

    The evaluation of underground radioactive waste storage tank structural integrity poses a unique set of challenges. Radiation fields, limited access, personnel safety and internal structures are just some of the problems faced. To examine the internal surfaces a sensor suite must be deployed as an end effector on a robotic arm. The purpose of this report is to examine the potential failure modes of the tanks, rank the viability of various NDE technologies for internal surface evaluation, select a technology for initial EE implementation, and project future needs for NDE EE sensor suites.

  11. Toward automated interpretation of integrated information: Managing "big data" for NDE

    NASA Astrophysics Data System (ADS)

    Gregory, Elizabeth; Lesthaeghe, Tyler; Holland, Stephen

    2015-03-01

    Large scale automation of NDE processes is rapidly maturing, thanks to recent improvements in robotics and the rapid growth of computer power over the last twenty years. It is fairly straightforward to automate NDE data collection itself, but the process of NDE remains largely manual. We will discuss three threads of technological needs that must be addressed before we are able to perform automated NDE. Spatial context, the first thread, means that each NDE measurement taken is accompanied by metadata that locates the measurement with respect to the 3D physical geometry of the specimen. In this way, the geometry of the specimen acts as a database key. Data context, the second thread, means that we record why the data was taken and how it was measured in addition to the NDE data itself. We will present our software tool that helps users interact with data in context, Databrowse. Condition estimation, the third thread, is maintaining the best possible knowledge of the condition (serviceability, degradation, etc.) of an object or part. In the NDE context, we can prospectively use Bayes' Theorem to integrate the data from each new NDE measurement with prior knowledge. These tools, combined with robotic measurements and automated defect analysis, will provide the information needed to make high-level life predictions and focus NDE measurements where they are needed most.

  12. NDE Software Developed at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Roth, Donald J.; Martin, Richard E.; Rauser, Richard W.; Nichols, Charles; Bonacuse, Peter J.

    2014-01-01

    NASA Glenn Research Center has developed several important Nondestructive Evaluation (NDE) related software packages for different projects in the last 10 years. Three of the software packages have been created with commercial-grade user interfaces and are available to United States entities for download on the NASA Technology Transfer and Partnership Office server (https://sr.grc.nasa.gov/). This article provides brief overviews of the software packages.

  13. Approaches to hybrid SHM and NDE of composite aerospace structures

    NASA Astrophysics Data System (ADS)

    Michaels, Jennifer E.; Dawson, Alexander J.; Michaels, Thomas E.; Ruzzene, Massimo

    2014-03-01

    Periodic inspection of aerospace structures, while essential for ensuring their safety, incurs significant costs over a structure's life and also can result in significant loss of service. Structural health monitoring (SHM), which is also referred to as in situ nondestructive evaluation (NDE), offers the promise of more frequent assessments of structural integrity with little or no loss of service; however, such systems are not in common use. Here we consider a combined SHM and NDE approach to inspection of composite, plate-like components where the SHM system detects sites of possible damage and the follow-up NDE method utilizes the in situ SHM sensors to facilitate the inspection. The specific SHM approach considered is that of a sparse guided wave array using simple transducers that are spatially distributed on the structure. The NDE approach is non-contact guided wavefield imaging whereby one or more of the SHM transducers is used as a source and full wavefield data are recorded over the area of interest. This method has the advantage over conventional ultrasonic methods of being non-contact and requiring minimal surface preparation. Sparse array and wavefield data from a composite specimen with simulated sites of damage are presented here to illustrate the concept. Damage is simulated via glued-on steel plate pieces at multiple locations, and localization is performed using delay-and-sum imaging. A small, single site of simulated damage is well-localized, whereas larger and multiple sites of damage are not; however, their presence is readily detected. The follow-up wavefield imaging using a single sparse array transducer as a source is able to not only locate the sites of damage, but is able to provide a reasonable estimate of their sizes.

  14. Technology Transfer of Plate Wave NDE to Ultrasonic Rotary Actuation

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Y.

    1995-01-01

    Plate waves have been the subject of NDE research and applications. These waves, also known as guided waves of Lamb waves, are formed in two distinct modes--symmetric and antisymmetric --depending on their vibration characteristics in relation to the plate geometry. Experiments have corroborated the predictions for various plate wave modes, allowing the elastic properties of composite materials and adhesive bonded joints to be determined.

  15. Nondestructive Examination of Possible PWSCC in Control Rod Drive Mechanism Housings

    SciTech Connect

    Doctor, Steven R.; Cumblidge, Stephen E.; Schuster, George J.; Harris, Rob V.; Crawford, Susan L.

    2007-01-01

    Studies being conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington are focused on assessing the effectiveness of nondestructive examination (NDE) techniques for inspecting control rod drive mechanism (CRDM) nozzles and J-groove weldments. The primary objective of this work is to provide information to the United States Nuclear Regulatory Commission (US NRC) on the effectiveness of NDE methods as related to the in-service inspection of CRDM nozzles and J-groove weldments, and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies. In describing two CRDM assemblies removed from service, decontaminated, and then used in a series of NDE measurements, this paper will address the following questions: 1) What did each technique detect? 2) What did each technique miss? and 3) How accurately did each technique characterize the detected flaws? Two CRDM assemblies including the CRDM nozzle, the J-groove weld, buttering, and a portion of the ferritic head material were selected for this study. One contained suspected PWSCC, based on in-service inspection data and through-wall leakage; the other contained evidence suggesting through-wall leakage, but this was unconfirmed. The selected NDE measurements follow standard industry techniques for conducting in-service inspections of CRDM nozzles and the crown of the J-groove welds and buttering. In addition, laboratory based NDE methods were employed to conduct inspections of the CRDM assemblies, with particular emphasis on inspecting the J-groove weld and buttering. This paper will also describe the NDE methods used and discuss the NDE results. Future work will involve using the results from these NDE studies to guide the development of a destructive characterization plan to reveal the crack morphology and a comparison of the degradation found by the destructive evaluation with the recorded NDE responses.

  16. NDE for Characterizing Oxidation Damage in Reinforced Carbon-Carbon

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  17. Probability of detection models for eddy current NDE methods

    SciTech Connect

    Rajesh, S.N.

    1993-04-30

    The development of probability of detection (POD) models for a variety of nondestructive evaluation (NDE) methods is motivated by a desire to quantify the variability introduced during the process of testing. Sources of variability involved in eddy current methods of NDE include those caused by variations in liftoff, material properties, probe canting angle, scan format, surface roughness and measurement noise. This thesis presents a comprehensive POD model for eddy current NDE. Eddy current methods of nondestructive testing are used widely in industry to inspect a variety of nonferromagnetic and ferromagnetic materials. The development of a comprehensive POD model is therefore of significant importance. The model incorporates several sources of variability characterized by a multivariate Gaussian distribution and employs finite element analysis to predict the signal distribution. The method of mixtures is then used for estimating optimal threshold values. The research demonstrates the use of a finite element model within a probabilistic framework to the spread in the measured signal for eddy current nondestructive methods. Using the signal distributions for various flaw sizes the POD curves for varying defect parameters have been computed. In contrast to experimental POD models, the cost of generating such curves is very low and complex defect shapes can be handled very easily. The results are also operator independent.

  18. Optimal matched filter design for ultrasonic NDE of coarse grain materials

    NASA Astrophysics Data System (ADS)

    Li, Minghui; Hayward, Gordon

    2016-02-01

    Coarse grain materials are widely used in a variety of key industrial sectors like energy, oil and gas, and aerospace due to their attractive properties. However, when these materials are inspected using ultrasound, the flaw echoes are usually contaminated by high-level, correlated grain noise originating from the material microstructures, which is time-invariant and demonstrates similar spectral characteristics as flaw signals. As a result, the reliable inspection of such materials is highly challenging. In this paper, we present a method for reliable ultrasonic non-destructive evaluation (NDE) of coarse grain materials using matched filters, where the filter is designed to approximate and match the unknown defect echoes, and a particle swarm optimization (PSO) paradigm is employed to search for the optimal parameters in the filter response with an objective to maximise the output signal-to-noise ratio (SNR). Experiments with a 128-element 5MHz transducer array on mild steel and INCONEL Alloy 617 samples are conducted, and the results confirm that the SNR of the images is improved by about 10-20 dB if the optimized matched filter is applied to all the A-scan waveforms prior to image formation. Furthermore, the matched filter can be implemented in real-time with low extra computational cost.

  19. New International Program to Asses the Reliability of Emerging Nondestructive Techniques (PARENT)

    SciTech Connect

    Prokofiev, Iouri; Cumblidge, Stephen E.; Csontos, Aladar A.; Braatz, Brett G.; Doctor, Steven R.

    2013-01-25

    The Nuclear Regulatory Commission (NRC) established the Program to Assess the Reliability of Emerging Nondestructive Techniques (PARENT) to follow on from the successful Program for the Inspection of Nickel alloy Components (PINC). The goal of the PARENT is to conduct a confirmatory assessment of the reliability of nondestructive evaluation (NDE) techniques for detecting and sizing primary water stress corrosion cracks (PWSCC) and applying the lessons learned from PINC to a series of round-robin tests. These open and blind round-robin tests will comprise a new set of typical pressure boundary components including dissimilar metal welds (DMWs) and bottom-mounted instrumentation penetrations. Open round-robin tests will engage research and industry teams worldwide to investigate and demonstrate the reliability of emerging NDE techniques to detect and size flaws with a wide range of lengths, depths, orientations, and locations. Blind round-robin tests will utilize various testing organizations, whose inspectors and procedures are certified by the standards for the nuclear industry in their respective countries, to investigate the ability of established NDE techniques to detect and size flaws whose characteristics range from relatively easy to very difficult for detection and sizing. Blind and open round-robin testing started in late 2011 and early 2012, respectively. This paper will present the work scope with reports on progress, NDE methods evaluated, and project timeline for PARENT.

  20. New international Program to Assess the Reliability of Emerging Nondestructive Techniques (PARENT)

    NASA Astrophysics Data System (ADS)

    Prokofiev, Iouri; Cumblidge, Stephen E.; Csontos, Aladar A.; Braatz, Brett G.; Doctor, Steven R.

    2013-01-01

    The Nuclear Regulatory Commission established the Program to Assess the Reliability of Emerging Nondestructive Techniques (PARENT) to follow on from the successful Program for the Inspection of Nickel alloy Components. The goals of PARENT are to conduct a confirmatory assessment of the reliability of nondestructive evaluation (NDE) techniques for detecting and sizing primary water stress corrosion cracks and apply the lessons learned from PINC to a series of round-robin tests. These open and blind round-robin tests will comprise a new set of typical pressure boundary components including dissimilar metal welds and bottom-mounted instrumentation penetrations. Open round-robin tests will engage research and industry teams worldwide to investigate and demonstrate the reliability of emerging NDE techniques to detect and size flaws with a wide range of lengths, depths, orientations, and locations. Blind round-robin tests will utilize various testing organizations, whose inspectors and procedures are certified by the standards for the nuclear industry in their respective countries, to investigate the ability of established NDE techniques to detect and size flaws whose characteristics range from relatively easy to very difficult for detection and sizing. Blind and open round-robin testing started in late 2011 and early 2012, respectively. This paper will present the work scope with reports on progress, NDE methods evaluated, and project timeline for PARENT.

  1. Recent advancements in the electromechanical (E/M) impedance method for structural health monitoring and NDE

    NASA Astrophysics Data System (ADS)

    Giurgiutiu, Victor; Rogers, Craig A.

    1998-07-01

    -mechanical impedance method is warranted. A further examination of the complex interaction between wave propagation, drive-point impedance, structural damage and electro-mechanical impedance of the piezo-electric wafer transducer is needed. Once these aspects are better understood, the E/M impedance method has the potential to become a widely used NDE technique with large applicability in diverse engineering fields (aerospace, automotive, infrastructure and biomedical implants).

  2. Iowa State University's undergraduate minor, online graduate certificate and resource center in NDE

    NASA Astrophysics Data System (ADS)

    Bowler, Nicola; Larson, Brian F.; Gray, Joseph N.

    2014-02-01

    Nondestructive evaluation is a `niche' subject that is not yet offered as an undergraduate or graduate major in the United States. The undergraduate minor in NDE offered within the College of Engineering at Iowa State University (ISU) provides a unique opportunity for undergraduate aspiring engineers to obtain a qualification in the multi-disciplinary subject of NDE. The minor requires 16 credits of course work within which a core course and laboratory in NDE are compulsory. The industrial sponsors of Iowa State's Center for Nondestructive Evaluation, and others, strongly support the NDE minor and actively recruit students from this pool. Since 2007 the program has graduated 10 students per year and enrollment is rising. In 2011, ISU's College of Engineering established an online graduate certificate in NDE, accessible not only to campus-based students but also to practicing engineers via the web. The certificate teaches the fundamentals of three major NDE techniques; eddy-current, ultrasonic and X-ray methods. This paper describes the structure of these programs and plans for development of an online, coursework-only, Master of Engineering in NDE and thesis-based Master of Science degrees in NDE.

  3. NDE of the universe - New ways to look at old facts

    NASA Technical Reports Server (NTRS)

    Vary, Alex

    1993-01-01

    The paper investigates the relation between cosmology and NDE, emphasizing the need for new approaches and models imposed by new space-age materials. These are frontier materials with tailored microstructures and specially designed properties, such as the ceramic and intermetallic matrix composites for very high temperature power and propulsion systems. These materials require new NDE approaches, which are discussed in this paper.

  4. Role of NDE in bridge health monitoring

    NASA Astrophysics Data System (ADS)

    Aktan, A. Emin; Grimmelsman, Kirk A.

    1999-02-01

    In the last decade, many advanced sensing and measurement technologies have been developed or transferred from defense use to infrastructure applications. It is now possible to measure various properties of a structural system, its elements and materials. However, the development of new technologies and tools should be considered in conjunction with fundamental changes and new paradigms as opposed to simple modifications to civil infrastructure systems engineering practice. It may be useful to start with a bold vision for an integrated bridge structural and operational management capability, and to properly design, develop, validate, demonstrate and standardize the technologies that are needed in conjunction with this vision. The term `health-monitoring', used in relation to intelligent infrastructure, will be helpful for formulating a complete and coherent vision for the bridge management of the future. The writers define `health monitoring,' as the measurement of the operating and loading environment and the critical responses of a structure in order to track and evaluate the symptoms of operational anomalies and/or deterioration or damage that may impact service or safety reliability.

  5. Novel NDE fiber optic corrosion sensor

    NASA Astrophysics Data System (ADS)

    Rutherford, Paul S.; Ikegami, Roy; Shrader, John E.; Sherrer, David; Zabaronick, Noel; Zeakes, Jason S.; Murphy, Kent A.; Claus, Richard O.

    1996-05-01

    Life extension programs for military metallic aircraft are becoming increasingly important as defense budgets shrink and world economies realign themselves to an uncertain future. For existing military weapon systems, metallic corrosion damage costs an estimated $8 billion per year. One approach to reducing this cost is to develop a reliable method to detect and monitor corrosion in hidden metallic structure with the use of corrosion sensors which would give an early indication of corrosion without significant disassembly. This paper describes the current status of the development, analysis, and testing of a fiber optic corrosion sensor developed jointly by Boeing and Virginia Tech Fiber & Electro-Optics Research Center and sponsored by USAF Wright Laboratory, Materials Directorate, contract #F33615-93-C-5368. In the sensor which is being developed under this contract, the normal cladding is removed in the sensor region, and replaced with aluminum alloy and allowed to corrode on coupons representative of C/KC-135 body structure in an ASTM B117 salt spray chamber. In this approach, the optical signal out of the sensor is designed to increase as corrosion takes place. These test results to determine the correlation between sensor output and structural degradation due to corrosion are discussed.

  6. Primary Water Stress Corrosion Crack Morphology and Nondestructive Evaluation Reliability

    SciTech Connect

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

    2004-12-01

    A research program on primary stress corrosion crack (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 compling a knowledge base on all cracking in nickel based materials at all degradation sites in nuclear power plants, assessing NDE methods using mockups to quantify the detection, sizing, and using mockups to quantify the detection sizing and characterization of tight cracks, and determining the role of welding processes in degradation. In this paper, the resuts of the initial literature searchs are presented. The relevant data on crack properties such as shape and orientation are presented and their impace on nondestructive evaluation (NDE) reliability is discussed.

  7. Recalibrating software reliability models

    NASA Technical Reports Server (NTRS)

    Brocklehurst, Sarah; Chan, P. Y.; Littlewood, Bev; Snell, John

    1989-01-01

    In spite of much research effort, there is no universally applicable software reliability growth model which can be trusted to give accurate predictions of reliability in all circumstances. Further, it is not even possible to decide a priori which of the many models is most suitable in a particular context. In an attempt to resolve this problem, techniques were developed whereby, for each program, the accuracy of various models can be analyzed. A user is thus enabled to select that model which is giving the most accurate reliability predictions for the particular program under examination. One of these ways of analyzing predictive accuracy, called the u-plot, in fact allows a user to estimate the relationship between the predicted reliability and the true reliability. It is shown how this can be used to improve reliability predictions in a completely general way by a process of recalibration. Simulation results show that the technique gives improved reliability predictions in a large proportion of cases. However, a user does not need to trust the efficacy of recalibration, since the new reliability estimates produced by the technique are truly predictive and so their accuracy in a particular application can be judged using the earlier methods. The generality of this approach would therefore suggest that it be applied as a matter of course whenever a software reliability model is used.

  8. Recalibrating software reliability models

    NASA Technical Reports Server (NTRS)

    Brocklehurst, Sarah; Chan, P. Y.; Littlewood, Bev; Snell, John

    1990-01-01

    In spite of much research effort, there is no universally applicable software reliability growth model which can be trusted to give accurate predictions of reliability in all circumstances. Further, it is not even possible to decide a priori which of the many models is most suitable in a particular context. In an attempt to resolve this problem, techniques were developed whereby, for each program, the accuracy of various models can be analyzed. A user is thus enabled to select that model which is giving the most accurate reliability predicitons for the particular program under examination. One of these ways of analyzing predictive accuracy, called the u-plot, in fact allows a user to estimate the relationship between the predicted reliability and the true reliability. It is shown how this can be used to improve reliability predictions in a completely general way by a process of recalibration. Simulation results show that the technique gives improved reliability predictions in a large proportion of cases. However, a user does not need to trust the efficacy of recalibration, since the new reliability estimates prodcued by the technique are truly predictive and so their accuracy in a particular application can be judged using the earlier methods. The generality of this approach would therefore suggest that it be applied as a matter of course whenever a software reliability model is used.

  9. Reliability training

    NASA Technical Reports Server (NTRS)

    Lalli, Vincent R. (Editor); Malec, Henry A. (Editor); Dillard, Richard B.; Wong, Kam L.; Barber, Frank J.; Barina, Frank J.

    1992-01-01

    Discussed here is failure physics, the study of how products, hardware, software, and systems fail and what can be done about it. The intent is to impart useful information, to extend the limits of production capability, and to assist in achieving low cost reliable products. A review of reliability for the years 1940 to 2000 is given. Next, a review of mathematics is given as well as a description of what elements contribute to product failures. Basic reliability theory and the disciplines that allow us to control and eliminate failures are elucidated.

  10. Ultrasonic Phased-Array Characterization for NDE Applications

    NASA Technical Reports Server (NTRS)

    Hanley, John J.; Tennis, Richard F.; Pickens, Keith S.

    1995-01-01

    Southwest Research Institute (SwRI) recently fabricated and delivered the 100-channel Ultrasonic Phased-Array Testbed System (UPATS) for NASA's Langley Research Center. NASA prepared the specifications and provided the funding to develop UPATS in order to provide a tool for the improvement of ultrasonic nondestructive evaluation (NDE) and characterization of materials. UPATS incorporates state-of-the-art phased-array concepts such as beam steering, focusing, apodization, and phase-sensitive detection which make it possible to develop more sophisticated testing methodologies. It also can be used to investigate fundamental ultrasonic propagation and detection phenomena such as refraction, diffraction, scattering, and beam broadening.

  11. Applications of holography to NDE at SNIAS-Aquitaine

    SciTech Connect

    Le Floch, C.; Bouteyre, J.

    1984-01-01

    The industrial use of holographic interferometry in the nondestructive testing of large composite structures is discussed and illustrated, with an emphasis on the evaluation of aerospace structures at SNIAS-Aquitaine, where the technique has been in routine use since 1983. The basic principles of the method are reviewed, and the applications described include NDE of flaws in a drilling pipe, an instrument casing, a power-plant cooling-tower model, the airframe of a Corvette aircraft, and a solid-fuel propulsion unit. Diagrams, photographs of the installation, and sample interferograms are shown. 9 references.

  12. Electronics speckle interferometry applications for NDE of spacecraft structural components

    NASA Astrophysics Data System (ADS)

    Rao, M. V.; Samuel, R.; Ananthan, A.; Dasgupta, S.; Nair, P. S.

    2008-09-01

    The spacecraft components viz., central cylinder, deck plates, solar panel substrates, antenna reflectors are made of aluminium/composite honeycomb sandwich construction. Detection of these defects spacecraft structural components is important to assess the integrity of the spacecraft structure. Electronic Speckle Interferometry (ESI) techniques identify the defects as anomalous regions in the interferometric fringe patterns of the specklegram while the component is suitably stressed to give rise to differential displacement/strain around the defective region. Calibration studies, different phase shifting methods associated with ESI and the development of a prototype Twin Head ESSI System (THESSIS) and its use for the NDE of a typical satellite structural component are presented.

  13. High Frequency Ultrasonic NDE of Titanium Metal Matrix Composites

    NASA Astrophysics Data System (ADS)

    Smith, Robert A.; Pettigrew, Irene; Kirk, Katherine

    2006-03-01

    Pulse-echo wave propagation through a multi-layered TiMMC with a honeycomb-layered structural arrangement was measured experimentally. Embedded in each of the layers are unidirectional, horizontally positioned, parallel oriented silicon carbide fibers cored with tungsten. During the manufacturing process it has been realised that NDE of TiMMC is necessary because fibers are vulnerable to misalignment and breakage resulting in a reduction in mechanical properties. In this paper, results show that frequency dependence exists within the structure. This paper presents the results of fiber position, waviness and orientation detection in TiMMCs. Influences of step size, transducer frequency, focus and filtering are investigated.

  14. The Development of NDE Techniques for Large Cryogenic Storage Tanks

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert; Starr, Stan; Parker, Don

    2008-01-01

    Objectives of this project are: (1) Develop and demonstrate NDE techniques to evaluate the condition of large cryogenic Dewars (typically 50,000 to 900,000 gaL). (2) These tanks are used across NASA for launch pads, engine test stands, cryogenic wind tunnels and other facilities: they represent a major investment. (3) Issues addressed: (1) Insulation integrity of existing Dewars (powdered insulation under vacuum or sometimes ambient pressure (LO2), (2) Post fabrication insulation verification without full chill-down to avoid thermal cycling the tank (fatigue limitation of piping and compaction of Perlite).

  15. Ultrasonic NDE of titanium diffusion bonds using signal phase

    NASA Astrophysics Data System (ADS)

    Escobar-Ruiz, E.; Cawley, P.; Nagy, P. B.; Collison, I.; Wright, D.

    2013-01-01

    Diffusion bonding is a highly advantageous solid-state welding method. However, its full exploitation in titanium components is currently limited by a lack of robust NDE techniques capable of detecting anything but gross bond-line defects. A novel ultrasonic technique has been developed to address this lack of capability. This technique, based on the ultrasonic signal phase, has been demonstrated in a `single-sided' scenario where only one side of the diffusion bond was accessible. Samples with differing degrees of bond quality were evaluated, and excellent agreement was found between the single-sided and double-sided experiments.

  16. Bond strength evaluation in adhesive joints using NDE and DIC methods

    NASA Astrophysics Data System (ADS)

    Poudel, Anish

    Adhesive bonding of graphite epoxy composite laminates to itself or traditional metal alloys in modern aerospace and aircraft structural applications offers an excellent opportunity to use the most efficient and intelligent combination of materials available thus providing an attractive package for efficient structural designs. However, one of the major issues of adhesive bonding is the occasional formation of interfacial defects such as kissing or weak bonds in the bondline interface. Also, there are shortcomings of existing non-destructive evaluation (NDE) methods to non-destructively detect/characterize these interfacial defects and reliably predicting the bond shear strength. As a result, adhesive bonding technology is still not solely implemented in primary structures of an aircraft. Therefore, there is a greater demand for a novel NDE tool that can meet the existing aerospace requirement for adhesive bondline characterization. This research implemented a novel Acoustography ultrasonic imaging and digital image correlation (DIC) technique to detect and characterize interfacial defects in the bondline and determine bond shear strength in adhesively bonded composite-metal joints. Adhesively bonded Carbon Fiber Reinforced Plastic (CFRP) laminate and 2024-T3 Aluminum single lap shear panels subjected to various implanted kissing/weak bond defects were the primary focus of this study. Kissing/weak bonds were prepared by controlled surface contamination in the composite bonding surface and also by improperly mixing the adhesive constituent. SEM analyses were also conducted to understand the surface morphology of substrates and their interaction with the contaminants. Morphological changes were observed in the microscopic scale and the chemical analysis confirmed the stability of the contaminant at or very close to the interface. In addition, it was also demonstrated that contaminants migrated during the curing of the adhesive from CFRP substrate which caused a

  17. Three-dimensional NDE of VHTR core components via simulation-based testing. Final report

    SciTech Connect

    Guzina, Bojan; Kunerth, Dennis

    2014-09-30

    A next generation, simulation-driven-and-enabled testing platform is developed for the 3D detection and characterization of defects and damage in nuclear graphite and composite structures in Very High Temperature Reactors (VHTRs). The proposed work addresses the critical need for the development of high-fidelity Non-Destructive Examination (NDE) technologies for as-manufactured and replaceable in-service VHTR components. Centered around the novel use of elastic (sonic and ultrasonic) waves, this project deploys a robust, non-iterative inverse solution for the 3D defect reconstruction together with a non-contact, laser-based approach to the measurement of experimental waveforms in VHTR core components. In particular, this research (1) deploys three-dimensional Scanning Laser Doppler Vibrometry (3D SLDV) as a means to accurately and remotely measure 3D displacement waveforms over the accessible surface of a VHTR core component excited by mechanical vibratory source; (2) implements a powerful new inverse technique, based on the concept of Topological Sensitivity (TS), for non-iterative elastic waveform tomography of internal defects - that permits robust 3D detection, reconstruction and characterization of discrete damage (e.g. holes and fractures) in nuclear graphite from limited-aperture NDE measurements; (3) implements state-of-the art computational (finite element) model that caters for accurately simulating elastic wave propagation in 3D blocks of nuclear graphite; (4) integrates the SLDV testing methodology with the TS imaging algorithm into a non-contact, high-fidelity NDE platform for the 3D reconstruction and characterization of defects and damage in VHTR core components; and (5) applies the proposed methodology to VHTR core component samples (both two- and three-dimensional) with a priori induced, discrete damage in the form of holes and fractures. Overall, the newly established SLDV-TS testing platform represents a next-generation NDE tool that surpasses

  18. Reliability Assessment of Ultrasonic Nondestructive Inspection Data Using Monte Carlo Simulation

    NASA Astrophysics Data System (ADS)

    Park, Ik-Keun; Kim, Hyun-Mook

    2003-03-01

    Ultrasonic NDE is one of important technologies in the life-time maintenance of nuclear power plant. Ultrasonic inspection system is consisted of the operator, equipment and procedure. The reliability of ultrasonic inspection system is affected by its ability. The performance demonstration round robin was conducted to quantify the capability of ultrasonic inspection for in-service. The small number of teams who employed procedures that met or exceeded ASME Sec. XI Code requirements detected the piping of nuclear power plant with various cracks to evaluate the capability of detection and sizing. In this paper, the statistical reliability assessment of ultrasonic nondestructive inspection data using Monte Carlo simulation is presented. The results of the probability of detection (POD) analysis using Monte Carlo simulation are compared to these of logistic probability model. In these results, Monte Carlo simulation was found to be very useful to the reliability assessment for the small NDE hit/miss data sets.

  19. Correlation Between NDE Measurements and Elongation of Aluminum

    SciTech Connect

    Thompson, R. Bruce; Margetan, Frank J.; Nakagawa, Norio; Haldipur, Pranaam

    2007-03-21

    Complex aluminum forgings can have engineering properties which vary with position due to changes in the underlying local metal microstructure. Consequently, the material properties may be in compliance with production requirements in some regions of the forging, but out of compliance in others. One conical Al-7050 forging of interest was found to have elongation properties which failed required tests in certain regions. NDE measurements sensitive to microstructural changes were carried out to search for correlations with elongation properties. The results of a set of initial feasibility experiments will be reported. Both ultrasonic and eddy current NDE methods were used, with the goal being to determine which properties were sensitive to the elongation. Ultrasonic testing included the measurement of longitudinal and shear-wave velocity, longitudinal wave attenuation, and longitudinal and shear-wave backscattered grain noise. All tests were performed with the sonic beam entering through the coupon face that would be adjacent to the outer surface of the forging. Only modest differences in wave speed and attenuation values were seen among the suite of coupons, but significant differences were seen in backscattered noise levels. These appeared to indicate changes in grain structure but only exhibited partial correlation with elongation. The eddy current measurements were designed to be sensitive to the electrical resistivity. Included were a number of measurement configurations and frequencies. The signals exhibited a significant correlation with elongation.

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

    NASA Technical Reports Server (NTRS)

    Walker, James L.

    1998-01-01

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

  1. NDE of Damage in Aircraft Flight Control Surfaces

    NASA Astrophysics Data System (ADS)

    Hsu, David K.; Barnard, Daniel J.; Dayal, Vinay

    2007-03-01

    Flight control surfaces on an aircraft, such as ailerons, flaps, spoilers and rudders, are typically adhesively bonded composite or aluminum honeycomb sandwich structures. These components can suffer from damage caused by hail stone, runway debris, or dropped tools during maintenance. On composites, low velocity impact damages can escape visual inspection, whereas on aluminum honeycomb sandwich, budding failure of the honeycomb core may or may not be accompanied by a disbond. This paper reports a study of the damage morphology in such structures and the NDE methods for detecting and characterizing them. Impact damages or overload failures in composite sandwiches with Nomex or fiberglass core tend to be a fracture or crinkle or the honeycomb cell wall located a distance below the facesheet-to-core bondline. The damage in aluminum honeycomb is usually a buckling failure, propagating from the top skin downward. The NDE methods used in this work for mapping out these damages were: air-coupled ultrasonic scan, and imaging by computer aided tap tester. Representative results obtained from the field will be shown.

  2. On-Line NDE for Advanced Reactor Designs

    NASA Astrophysics Data System (ADS)

    Nakagawa, N.; Inanc, F.; Thompson, R. B.; Junker, W. R.; Ruddy, F. H.; Beatty, J. M.; Arlia, N. G.

    2003-03-01

    This expository paper introduces the concept of on-line sensor methodologies for monitoring the integrity of components in next generation power systems, and explains general benefits of the approach, while describing early conceptual developments of suitable NDE methodologies. The paper first explains the philosophy behind this approach (i.e. the design-for-inspectability concept). Specifically, we describe where and how decades of accumulated knowledge and experience in nuclear power system maintenance are utilized in Generation IV power system designs, as the designs are being actively developed, in order to advance their safety and economy. Second, we explain that Generation IV reactor design features call for the replacement of the current outage-based maintenance by on-line inspection and monitoring. Third, the model-based approach toward design and performance optimization of on-line sensor systems, using electromagnetic, ultrasonic, and radiation detectors, will be explained. Fourth, general types of NDE inspections that are considered amenable to on-line health monitoring will be listed. Fifth, we will describe specific modeling developments to be used for radiography, EMAT UT, and EC detector design studies.

  3. FROM NDE WITH A Q TO SHM AND BEYOND

    SciTech Connect

    Achenbach, J. D.

    2009-03-03

    In the nineteen-sixties, a significant limitation of NDI and NDE became apparent with the advent of fracture mechanics. Fracture mechanics requires quantitative information on defects, which has to be obtained from quantitative non-destructive testing. A DARPA Program directed by Don Thompson provided the point of departure for the journey to put the Q with NDE. The DARPA Program, and subsequent DOD, FAA and industrial programs produced seminal results for diagnostics and prognostics. In diagnostics, measurement models, probability of detection considerations and techniques of defect characterization were developed, which were complemented by damage evolution laws, probabilistic failure analysis and damage progression estimates, for methods of prognostication. The new results in QNDE naturally led to the concept of structural health monitoring (SHM), whereby sensors are permanently installed on structures. An SHM system can provide on-demand (or continuous) information on the state of a structure, so that an assessment of the structural integrity can be made at any time, and timely remedial actions can be taken. In this paper, we review the development of QNDE towards SHM. Sensor development, data processing, materials engineering and solid mechanics play dominant roles in both the diagnostic and the prognostic components of SHM. A probabilistic approach is essential, as will be shown by examples of pre-crack fatigue damage, crack growth and optimization of an inspection schedule.

  4. Severe NDE1-mediated microcephaly results from neural progenitor cell cycle arrests at multiple specific stages.

    PubMed

    Doobin, David J; Kemal, Shahrnaz; Dantas, Tiago J; Vallee, Richard B

    2016-01-01

    Microcephaly is a cortical malformation disorder characterized by an abnormally small brain. Recent studies have revealed severe cases of microcephaly resulting from human mutations in the NDE1 gene, which is involved in the regulation of cytoplasmic dynein. Here using in utero electroporation of NDE1 short hairpin RNA (shRNA) in embryonic rat brains, we observe cell cycle arrest of proliferating neural progenitors at three distinct stages: during apical interkinetic nuclear migration, at the G2-to-M transition and in regulation of primary cilia at the G1-to-S transition. RNAi against the NDE1 paralogue NDEL1 has no such effects. However, NDEL1 overexpression can functionally compensate for NDE1, except at the G2-to-M transition, revealing a unique NDE1 role. In contrast, NDE1 and NDEL1 RNAi have comparable effects on postmitotic neuronal migration. These results reveal that the severity of NDE1-associated microcephaly results not from defects in mitosis, but rather the inability of neural progenitors to ever reach this stage. PMID:27553190

  5. Severe NDE1-mediated microcephaly results from neural progenitor cell cycle arrests at multiple specific stages

    PubMed Central

    Doobin, David J.; Kemal, Shahrnaz; Dantas, Tiago J.; Vallee, Richard B.

    2016-01-01

    Microcephaly is a cortical malformation disorder characterized by an abnormally small brain. Recent studies have revealed severe cases of microcephaly resulting from human mutations in the NDE1 gene, which is involved in the regulation of cytoplasmic dynein. Here using in utero electroporation of NDE1 short hairpin RNA (shRNA) in embryonic rat brains, we observe cell cycle arrest of proliferating neural progenitors at three distinct stages: during apical interkinetic nuclear migration, at the G2-to-M transition and in regulation of primary cilia at the G1-to-S transition. RNAi against the NDE1 paralogue NDEL1 has no such effects. However, NDEL1 overexpression can functionally compensate for NDE1, except at the G2-to-M transition, revealing a unique NDE1 role. In contrast, NDE1 and NDEL1 RNAi have comparable effects on postmitotic neuronal migration. These results reveal that the severity of NDE1-associated microcephaly results not from defects in mitosis, but rather the inability of neural progenitors to ever reach this stage. PMID:27553190

  6. Overview of the National Aeronautics and Space Administration's Nondestructive Evaluation (NDE) Program

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    2002-01-01

    NASA's Office of Safety and Mission Assurance sponsors an Agency-wide NDE Program that supports Aeronautics and Space Transportation Technology, Human Exploration and Development of Space, Earth Science, and Space Science Enterprises. For each of these Enterprises, safety is the number one priority. Development of the next generation aero-space launch and transportation vehicles, satellites, and deep space probes have highlighted the enabling role that NDE plays in these advanced technology systems. Specific areas of advanced component development, component integrity, and structural heath management are critically supported by NDE technologies. The simultaneous goals of assuring safety, maintaining overall operational efficiency, and developing and utilizing revolutionary technologies to expand human activity and space-based commerce in the frontiers of air and space places increasing demands on the Agencies NDE infrastructure and resources. In this presentation, an overview of NASA's NDE Program will be presented, that includes a background and status of current Enterprise NDE issues, and the NDE investment areas being developed to meet Enterprise safety and mission assurance needs through the year 2009 and beyond.

  7. Dynein Separately Partners with NDE1 and Dynactin To Orchestrate T Cell Focused Secretion.

    PubMed

    Nath, Shubhankar; Christian, Laura; Tan, Sarah Youngsun; Ki, Sanghee; Ehrlich, Lauren I R; Poenie, Martin

    2016-09-15

    Helper and cytotoxic T cells accomplish focused secretion through the movement of vesicles toward the microtubule organizing center (MTOC) and translocation of the MTOC to the target contact site. In this study, using Jurkat cells and OT-I TCR transgenic primary murine CTLs, we show that the dynein-binding proteins nuclear distribution E homolog 1 (NDE1) and dynactin (as represented by p150(Glued)) form mutually exclusive complexes with dynein, exhibit nonoverlapping distributions in target-stimulated cells, and mediate different transport events. When Jurkat cells expressing a dominant negative form of NDE1 (NDE1-enhanced GFP fusion) were activated by Staphylococcus enterotoxin E-coated Raji cells, NDE1 and dynein failed to accumulate at the immunological synapse (IS) and MTOC translocation was inhibited. Knockdown of NDE1 in Jurkat cells or primary mouse CTLs also inhibited MTOC translocation and CTL-mediated killing. In contrast to NDE1, knockdown of p150(Glued), which depleted the alternative dynein/dynactin complex, resulted in impaired accumulation of CTLA4 and granzyme B-containing intracellular vesicles at the IS, whereas MTOC translocation was not affected. Depletion of p150(Glued) in CTLs also inhibited CTL-mediated lysis. We conclude that the NDE1/Lissencephaly 1 and dynactin complexes separately mediate two key components of T cell-focused secretion, namely translocation of the MTOC and lytic granules to the IS, respectively. PMID:27534551

  8. Ensemble of classifiers for confidence-rated classification of NDE signal

    NASA Astrophysics Data System (ADS)

    Banerjee, Portia; Safdarnejad, Seyed; Udpa, Lalita; Udpa, Satish

    2016-02-01

    Ensemble of classifiers in general, aims to improve classification accuracy by combining results from multiple weak hypotheses into a single strong classifier through weighted majority voting. Improved versions of ensemble of classifiers generate self-rated confidence scores which estimate the reliability of each of its prediction and boost the classifier using these confidence-rated predictions. However, such a confidence metric is based only on the rate of correct classification. In existing works, although ensemble of classifiers has been widely used in computational intelligence, the effect of all factors of unreliability on the confidence of classification is highly overlooked. With relevance to NDE, classification results are affected by inherent ambiguity of classifica-tion, non-discriminative features, inadequate training samples and noise due to measurement. In this paper, we extend the existing ensemble classification by maximizing confidence of every classification decision in addition to minimizing the classification error. Initial results of the approach on data from eddy current inspection show improvement in classification performance of defect and non-defect indications.

  9. Reliability physics

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.; Ross, R. G., Jr.

    1984-01-01

    Speakers whose topics relate to the reliability physics of solar arrays are listed and their topics briefly reviewed. Nine reports are reviewed ranging in subjects from studies of photothermal degradation in encapsulants and polymerizable ultraviolet stabilizers to interface bonding stability to electrochemical degradation of photovoltaic modules.

  10. Composite Stress Rupture NDE Research and Development Project (Kevlar[R] and Carbon)

    NASA Technical Reports Server (NTRS)

    Saulsberry, Regor

    2010-01-01

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

  11. The Development of NDE TEchniques for Payload Fairings and Other Composite Structures

    NASA Technical Reports Server (NTRS)

    Nurge, Mark; Youngquist, Robert; Starr, Stanley; Bartha, Bence; Hope, Dale; Carlson, Jeff

    2008-01-01

    The Objective of the project is to develop and demonstrate NDE techniques to assist in the fabrication and operational monitoring of expendable vehicle payload fairings and other composite structures.

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

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Parker, F. Raymond

    2014-01-01

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

  13. p-version finite element modeling for NDE

    NASA Astrophysics Data System (ADS)

    Issa, Camille A.; Balasubramaniam, Krishnan

    The formulation for the quadrilateral element of a p-version FEM for NDE is presented. Nodal shape, side shape, and internal shape functions are derived. The problem of wave propagation in solids is investigated using a Newmark direct integration scheme applied to p-version FEM meshes. It is found that numerical noise prevails for all the time steps and along the whole structure, and that there is no apparent wave propagation phenomenon in the displacement time-history. The numerical noise suggests that the abrupt change in the element material properties between the different layers of composite material and glue resin is a fatal modeling defect. The negative effect of using higher order p-version elements and the abrupt change of the element material properties should be countered by using a greater number of elements to model each layer and higher order mapping functions in the mapping process.

  14. Advanced NDE research in electromagnetic, thermal, and coherent optics

    NASA Technical Reports Server (NTRS)

    Skinner, S. Ballou

    1992-01-01

    A new inspection technology called magneto-optic/eddy current imaging was investigated. The magneto-optic imager makes readily visible irregularities and inconsistencies in airframe components. Other research observed in electromagnetics included (1) disbond detection via resonant modal analysis; (2) AC magnetic field frequency dependence of magnetoacoustic emission; and (3) multi-view magneto-optic imaging. Research observed in the thermal group included (1) thermographic detection and characterization of corrosion in aircraft aluminum; (2) a multipurpose infrared imaging system for thermoelastic stress detection; (3) thermal diffusivity imaging of stress induced damage in composites; and (4) detection and measurement of ice formation on the space shuttle main fuel tank. Research observed in the optics group included advancements in optical nondestructive evaluation (NDE).

  15. HEXAGONAL ARRAY STRUCTURE FOR 2D NDE APPLICATIONS

    SciTech Connect

    Dziewierz, J.; Ramadas, S. N.; Gachagan, A.; O'Leary, R. L.

    2010-02-22

    This paper describes a combination of simulation and experimentation to evaluate the advantages offered by utilizing a hexagonal shaped array element in a 2D NDE array structure. The active material is a 1-3 connectivity piezoelectric composite structure incorporating triangular shaped pillars--each hexagonal array element comprising six triangular pillars. A combination of PZFlex, COMSOL and Matlab has been used to simulate the behavior of this device microstructure, for operation around 2.25 MHz, with unimodal behavior and low levels of mechanical cross-coupling predicted. Furthermore, the application of hexagonal array elements enables the array aperture to increase by approximately 30%, compared to a conventional orthogonal array matrix and hence will provide enhanced volumetric coverage and SNR. Prototype array configurations demonstrate good corroboration of the theoretically predicted mechanical cross-coupling between adjacent array elements (approx23 dB).

  16. Comparison of normal and phase stepping shearographic NDE

    NASA Astrophysics Data System (ADS)

    Andhee, A.; Gryzagoridis, J.; Findeis, D.

    2005-05-01

    The paper presents results of non-destructive testing of composite main rotor helicopter blade calibration specimens using the laser based optical NDE technique known as Shearography. The tests were performed initially using the already well established near real-time non-destructive technique of Shearography, with the specimens perturbed during testing for a few seconds using the hot air from a domestic hair dryer. Subsequent to modification of the shearing device utilized in the shearographic setup, phase stepping of one of the sheared images to be captured by the CCD camera was enabled and identical tests were performed on the composite main rotor helicopter blade specimens. Considerable enhancement of the images manifesting or depicting the defects on the specimens is noted suggesting that phase stepping is a desirable enhancement technique to the traditional Shearographic setup.

  17. Considerations for ultrasonic testing application for on-orbit NDE

    NASA Astrophysics Data System (ADS)

    Koshti, Ajay M.

    2015-04-01

    The paper addresses some on-orbit nondestructive evaluation (NDE) needs of NASA for International Space Station (ISS). The presentation gives NDE requirements for inspecting suspect damage due to micro-meteoroids and orbital debris (MMOD) impact on the pressure wall of the ISS. This inspection is meant to be conducted from inside of the ISS module. The metallic wall of the module has a fixed wall thickness but also has integral orthogrid ribs for reinforcement. Typically, a single MMOD hit causes localized damage in a small area causing loss of material similar to pitting corrosion, but cracks may be present too. The impact may cause bulging of the wall. Results of the ultrasonic and eddy current demonstration scans on test samples are provided. The ultrasonic technique uses shear wave scans to interrogate the localized damage area from the surrounding undamaged area. The scanning protocol results in multiple scans, each with multiple "vee" paths. A superimposition and mosaic of the three-dimensional ultrasonic data from individual scans is desired to create C-scan images of the damage. This is a new data reduction process which is not currently implemented in state-of-art ultrasonic instruments. Results of ultrasonic scans on the simulated MMOD damage test plates are provided. The individual C-scans are superimposed manually creating mosaic of the inspection. The resulting image is compared with visibly detected damage boundaries, X-ray images, and localized ultrasonic and eddy current scans for locating crack tips to assess effectiveness of the ultrasonic scanning. The paper also discusses developments needed in improving ergonomics of the ultrasonic testing for on-orbit applications.

  18. Composite Flywheels Assessed Analytically by NDE and FEA

    NASA Technical Reports Server (NTRS)

    Abdul-Aziz, Ali; Baaklini, George Y.

    2000-01-01

    As an alternative to expensive and short-lived lead-acid batteries, composite flywheels are being developed to provide an uninterruptible power supply for advanced aerospace and industrial applications. Flywheels can help prevent irregularities in voltage caused by power spikes, sags, surges, burnout, and blackouts. Other applications include load-leveling systems for wind and solar power facilities, where energy output fluctuates with weather. Advanced composite materials are being considered for these components because they are significantly lighter than typical metallic alloys and have high specific strength and stiffness. However, much more research is needed before these materials can be fully utilized, because there is insufficient data concerning their fatigue characteristics and nonlinear behavior, especially at elevated temperatures. Moreover, these advanced types of structural composites pose greater challenges for nondestructive evaluation (NDE) techniques than are encountered with typical monolithic engineering metals. This is particularly true for ceramic polymer and metal matrix composites, where structural properties are tailored during the processing stages. Current efforts involving the NDE group at the NASA Glenn Research Center at Lewis Field are focused on evaluating many important structural components, including the flywheel system. Glenn's in-house analytical and experimental capabilities are being applied to analyze data produced by computed tomography (CT) scans to help assess the damage and defects of high-temperature structural composite materials. Finite element analysis (FEA) has been used extensively to model the effects of static and dynamic loading on aerospace propulsion components. This technique allows the use of complicated loading schemes by breaking the complex part geometry into many smaller, geometrically simple elements.

  19. Assessment of NDE Technologies for Detection and Characterization of Stress Corrosion Cracking in LWRs

    SciTech Connect

    Meyer, Ryan M.; Ramuhalli, Pradeep; Toloczko, Mychailo B.; Bond, Leonard J.; Montgomery, Robert O.

    2012-12-31

    Stress corrosion cracking (SCC) in light water reactors (LWRs) has been a persistent form of degradation in the nuclear industry. Examples of SCC can be found for a range of materials in boiling and pressurized water reactor environments, including carbon steels, stainless steels, and nickel-base stainless alloys. The evolution of SCC is often characterized by a long initiation stage followed by a phase of more rapid crack growth to failure. This provides a relatively short window of opportunity to detect the start of observable SCC, and it is conceivable that SCC could progress from initiation to failure between subsequent examinations when managed by applying periodic in-service inspection techniques. Implementation of advanced aging management paradigms in the current fleet of LWRs will require adaptation of existing measurement technologies and development of new technologies to perform on-line measurements during reactor operation to ensure timely detection of material degradation and to support the implementation of advanced diagnostics and prognostics. This paper considers several non-destructive examination (NDE) technologies with known sensitivity to detection of indicators for SCC initiation and/or propagation, and assesses these technologies with respect to their ability to detect and accurately characterize the significance of an SCC flaw. Potential strategies to improve SCC inspection or monitoring performance are offered to benefit management of SCC degradation in LWRs.

  20. Multidisciplinary System Reliability Analysis

    NASA Technical Reports Server (NTRS)

    Mahadevan, Sankaran; Han, Song; Chamis, Christos C. (Technical Monitor)

    2001-01-01

    The objective of this study is to develop a new methodology for estimating the reliability of engineering systems that encompass multiple disciplines. The methodology is formulated in the context of the NESSUS probabilistic structural analysis code, developed under the leadership of NASA Glenn Research Center. The NESSUS code has been successfully applied to the reliability estimation of a variety of structural engineering systems. This study examines whether the features of NESSUS could be used to investigate the reliability of systems in other disciplines such as heat transfer, fluid mechanics, electrical circuits etc., without considerable programming effort specific to each discipline. In this study, the mechanical equivalence between system behavior models in different disciplines are investigated to achieve this objective. A new methodology is presented for the analysis of heat transfer, fluid flow, and electrical circuit problems using the structural analysis routines within NESSUS, by utilizing the equivalence between the computational quantities in different disciplines. This technique is integrated with the fast probability integration and system reliability techniques within the NESSUS code, to successfully compute the system reliability of multidisciplinary systems. Traditional as well as progressive failure analysis methods for system reliability estimation are demonstrated, through a numerical example of a heat exchanger system involving failure modes in structural, heat transfer and fluid flow disciplines.

  1. Network reliability

    NASA Technical Reports Server (NTRS)

    Johnson, Marjory J.

    1985-01-01

    Network control (or network management) functions are essential for efficient and reliable operation of a network. Some control functions are currently included as part of the Open System Interconnection model. For local area networks, it is widely recognized that there is a need for additional control functions, including fault isolation functions, monitoring functions, and configuration functions. These functions can be implemented in either a central or distributed manner. The Fiber Distributed Data Interface Medium Access Control and Station Management protocols provide an example of distributed implementation. Relative information is presented here in outline form.

  2. Nondestructive and Destructive Examination Studies on Removed-from-Service Control Rod Drive Mechanism Penetrations

    SciTech Connect

    Cumblidge, Stephen E.; Crawford, Susan L.; Doctor, Steven R.; Seffens, Rob J.; Schuster, George J.; Toloczko, Mychailo B.; Harris, Robert V.; Bruemmer, Stephen M.

    2007-06-07

    Studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, focused on assessing the effectiveness of nondestructive examination (NDE) techniques for inspecting control rod drive mechanism (CRDM) nozzles and J-groove weldments. The primary objectives of this work are to provide information to the U.S. Nuclear Regulatory Commission (NRC) on the effectiveness of NDE methods as related to the in-service inspection of CRDM nozzles and J-groove weldments and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies. Two CRDM assemblies were removed from service, decontaminated, and then used in a series of NDE and destructive examination (DE) measurements; this report addresses the following questions: 1) What did each NDE technique detect? 2) What did each NDE technique miss? 3) How accurately did each NDE technique characterize the detected flaws? 4) Why did the NDE techniques perform or not perform? Two CRDM assemblies including the CRDM nozzle, the J-groove weld, buttering, and a portion of the ferritic head material were selected for this study. This report focuses on a CRDM assembly that contained suspected PWSCC, based on in-service inspection data and through-wall leakage. The NDE measurements used to examine the CRDM assembly followed standard industry techniques for conducting in-service inspections of CRDM nozzles and the crown of the J-groove welds and buttering. These techniques included eddy current testing (ET), time-of-flight diffraction ultrasound, and penetrant testing. In addition, laboratory-based NDE methods were employed to conduct inspections of the CRDM assembly with particular emphasis on inspecting the J-groove weld and buttering. These techniques included volumetric ultrasonic inspection of the J-groove weld metal and visual testing via replicant material of the J-groove weld. The results from these NDE studies were used to

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

    SciTech Connect

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

    1998-09-01

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

  4. NDE of composite structures using microwave time reversal imaging

    NASA Astrophysics Data System (ADS)

    Mukherjee, Saptarshi; Tamburrino, Antonello; Udpa, Lalita; Udpa, Satish

    2016-02-01

    Composite materials are being increasingly used to replace metals, partially or completely, in aerospace, shipping and automotive industries because of their light weight, corrosion resistance, and mechanical strength. Integrity of these materials may be compromised during manufacturing or due to impact damage during usage, resulting in defects such as porosity, delamination, cracks and disbonds. Microwave NDE techniques have the ability to propagate through composite materials, without suffering much attenuation. The scattered fields depend on the dielectric properties of the medium, and hence provide information about the structural integrity of these materials. Time Reversal focusing is based on the fact that when a wave solution is reversed in time and back propagated it refocuses back at the source. This paper presents a model based parametric study of time reversal principles with microwave data in composite materials. A two dimensional FDTD model is developed to implement the forward and time reversed electromagnetic wave propagation in a test geometry comprising metal-composite structures. Simulation results demonstrate the feasibility of this approach to detect and characterize different defects.

  5. Nde for Water Ingression in Composite Radomes on Aircraft

    NASA Astrophysics Data System (ADS)

    Hsu, David K.; Barnard, Daniel J.; Kite, Adam H.; Kim, Ki-Bok

    2008-02-01

    Aircraft radomes, being an electronic window for the radar, are made of nonconducting composite sandwiches with glass or silica fiber-reinforced facesheet and Nomex honeycomb or foam core. Trapped water or moisture can produce shadow on the image and severely degrade the performance of the radar. To detect water ingression in radomes, the available NDE techniques include x-ray radiography, infrared thermography, and a radome moisture meter that measures the RF power loss caused by the presence of water. In this work we explore the utility of commercially available capacitive sensors with co-planar electrodes that measure the change of the dielectric constant in the fringing field. These capacitive sensors, such as the electronic stud finder and moisture meters for wood, can exploit the large dielectric constant of water and serve as one-sided detectors for water and moisture in radomes. The sensitivities of the various moisture meters were compared in the experimental detection of water introduced into radome panels and water and moisture trapped in retired radomes.

  6. Utilizing Ebsd to Validate and Understand Nde Techniques

    NASA Astrophysics Data System (ADS)

    Essex, S. D.; Potter, M. D. G.; Vann, R.; Dixon, S.

    2009-03-01

    Electron Backscatter Diffraction (EBSD) is a destructive, surface-specific technique that measures accurately crystallographic orientations within a scanning electron microscope (SEM). From this data we can infer elastic properties, calculate levels of stress and measure microstructural properties such as the size and aspect ratios of grains. The Electromagnetic Acoustic Transducer (EMAT) is a non-contact, ultrasonic transducer that is suitable for operation on electrically conducting materials such as Aluminium and Steel. This paper highlights some of the work carried out using EBSD as a technique to validate EMAT measurements on rolled sheet to determine microstructural properties such as grain size and aspect ratios via shear wave through-thickness attenuation, and other macroscopic properties like average crystallographic texture. Work is also presented on another application for EBSD, in that it can be used to confirm whether an NDE technique is in fact nondestructive. Here we look at the case of a Nd:Yag pulsed laser irradiating a sample, in the ablative/thermoelastic regime boundary.

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

    NASA Astrophysics Data System (ADS)

    Zimdars, David

    2005-03-01

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

  8. Modeling of eddy current NDE probe for steam generator tubes.

    SciTech Connect

    Chang, F. C.; Bakhtiari, S.; Kupperman, D.

    2003-01-29

    Calculations were performed with a three-dimensional (3-D) finite-element model to describe the response of an eddy current (EC) probe to defects in steam generator (SG) tubing of a nuclear reactor. Such calculations could be very helpful in understanding and interpreting the EC probe response to complex tube/defect geometries associated with longitudinal inner/outer notches, roll transitions, sludge, and through-wall holes in SG tubes. The governing field equations are derived in terms of coupled magnetic vector and electric scalar potentials in the conducting media and total or reduced scalar potentials in the non-conducting regions. To assess the validity of the model, we compared the signal responses for two numerical approaches, stored-energy-and-power-loss approach and magnetic-flux approach for various tube/defect geometries. Simulation results are also presented on the tube/defect geometries for the pancake coil response and the transmitter/receiver (T/R) probe response. The results indicate that the eddy-current NDE modeling is capable of predicting EC probe response to flaws in steam generator tubes.

  9. NDE for the ARES I Upper Stage Common Bulkhead

    NASA Technical Reports Server (NTRS)

    Walker, James

    2008-01-01

    The current design of the ARES 1 Upper Stage uses a common bulkhead to separate the liquid hydrogen and liquid oxygen tanks. The bulkhead consists of aluminum face sheets bonded to a Phenolic honeycomb core. The face sheets, or domes, are friction stir welded to Y-rings that connect the bulkhead to the barrel sections of the liquid hydrogen and liquid oxygen tanks. Load between the Y-rings is carried by an externally attached bolting ring. The development of nondestructive evaluation methods for the ARES I Upper Stage Common Bulkhead are outlined in this presentation. Methods for inspecting the various components of the bulkhead are covered focusing in on the dome skins, core-to-dome bond lines and friction stir welds as well as structural details like the fastener holes. Thermography, shearography and ultrasonic methods are discussed for the bond lines. Eddy current methods are discussed for the fastener holes and dome skins. A combination of phased array ultrasound, liquid penetrant and radiography are to being investigated for use on the friction stir welds. Keywords: Composite materials, NDE, Cryogenic structures

  10. DISC1, PDE4B, and NDE1 at the centrosome and synapse

    SciTech Connect

    Bradshaw, Nicholas J.; Ogawa, Fumiaki; Antolin-Fontes, Beatriz; Chubb, Jennifer E.; Carlyle, Becky C.; Christie, Sheila; Claessens, Antoine; Porteous, David J.; Millar, J. Kirsty

    2008-12-26

    Disrupted-In-Schizophrenia 1 (DISC1) is a risk factor for schizophrenia and other major mental illnesses. Its protein binding partners include the Nuclear Distribution Factor E Homologs (NDE1 and NDEL1), LIS1, and phosphodiesterases 4B and 4D (PDE4B and PDE4D). We demonstrate that NDE1, NDEL1 and LIS1, together with their binding partner dynein, associate with DISC1, PDE4B and PDE4D within the cell, and provide evidence that this complex is present at the centrosome. LIS1 and NDEL1 have been previously suggested to be synaptic, and we now demonstrate localisation of DISC1, NDE1, and PDE4B at synapses in cultured neurons. NDE1 is phosphorylated by cAMP-dependant Protein Kinase A (PKA), whose activity is, in turn, regulated by the cAMP hydrolysis activity of phosphodiesterases, including PDE4. We propose that DISC1 acts as an assembly scaffold for all of these proteins and that the NDE1/NDEL1/LIS1/dynein complex is modulated by cAMP levels via PKA and PDE4.

  11. Three-Dimensional Regulation of Radial Glial Functions by Lis1-Nde1 and Dystrophin Glycoprotein Complexes

    PubMed Central

    Pawlisz, Ashley S.; Feng, Yuanyi

    2011-01-01

    Radial glial cells (RGCs) are distinctive neural stem cells with an extraordinary slender bipolar morphology and dual functions as precursors and migration scaffolds for cortical neurons. Here we show a novel mechanism by which the Lis1-Nde1 complex maintains RGC functions through stabilizing the dystrophin/dystroglycan glycoprotein complex (DGC). A direct interaction between Nde1 and utrophin/dystrophin allows for the assembly of a multi-protein complex that links the cytoskeleton to the extracellular matrix of RGCs to stabilize their lateral membrane, cell-cell adhesion, and radial morphology. Lis1-Nde1 mutations destabilized the DGC and resulted in deformed, disjointed RGCs and disrupted basal lamina. Besides impaired RGC self-renewal and neuronal migration arrests, Lis1-Nde1 deficiencies also led to neuronal over-migration. Additional to phenotypic resemblances of Lis1-Nde1 with DGC, strong synergistic interactions were found between Nde1 and dystroglycan in RGCs. As functional insufficiencies of LIS1, NDE1, and dystroglycan all cause lissencephaly syndromes, our data demonstrated that a three-dimensional regulation of RGC's cytoarchitecture by the Lis1-Nde1-DGC complex determines the number and spatial organization of cortical neurons as well as the size and shape of the cerebral cortex. PMID:22028625

  12. EVALUATION OF TRANSPORTATION OPTIONS FOR INTERMEDIATE NON DESTRUCTIVE EXAMINATIONS

    SciTech Connect

    Case, Susan; Hoggard, Gary

    2014-07-01

    Idaho National Laboratory (INL) shipments of irradiated experiments from the Advanced Test Reactor (ATR) to the Hot Fuels Examination Facility (HFEF) have historically been accomplished using the General Electric Model 2000 (GE 2000) Type B shipping container. Battelle Energy Alliance (BEA) concerns regarding the future availability and leasing and handling costs associated with the GE 2000 cask have warranted an evaluation of alternative shipping options. One or more of these shipping options may be utilized to perform non destructive examinations (NDE) such as neutron radiography and precision gamma scans of irradiated experiments at HFEF and then return the experiments to ATR for further irradiation, hereafter referred to as “intermediate NDE.”

  13. NDE of thermal protection system for space shuttle solid rocket booster

    NASA Technical Reports Server (NTRS)

    Myers, R. S.

    1990-01-01

    Potential nondestructive test (NDE) methods were evaluated for detecting debonds and weak bonds in the thermal protection system (TPS) for the space shuttle solid rocket boosters. The primary thermal protection material is a sprayable, thick epoxy coating that is filled with lightweight and thermal insulating materials. Test panels were fabricated with a wide variety of hidden realistic defects, including contact debonds and weak bonds. Nondestructive test results were obtained. Candidate NDE methods evaluated for booster production applications include laser interferometry (e.g., electronic shearography), infrared thermography, radiography (e.g., computed tomography), acousto-ultrasonics, mechanical/acoustic impedance, ultrasonics, acoustic emission, and the tap test. Capabilities, advantages, disadvantages, and relative performances in defect detection of each test method for TPS bonding applications are reported. Electronic shearography NDE was technically the superior method for detecting debonds.

  14. Particle-Filter-Based Multisensor Fusion For Solving Low-Frequency Electromagnetic NDE Inverse Problems

    SciTech Connect

    Khan, T.; Ramuhalli, Pradeep; Dass, Sarat

    2011-06-30

    Flaw profile characterization from NDE measurements is a typical inverse problem. A novel transformation of this inverse problem into a tracking problem, and subsequent application of a sequential Monte Carlo method called particle filtering, has been proposed by the authors in an earlier publication [1]. In this study, the problem of flaw characterization from multi-sensor data is considered. The NDE inverse problem is posed as a statistical inverse problem and particle filtering is modified to handle data from multiple measurement modes. The measurement modes are assumed to be independent of each other with principal component analysis (PCA) used to legitimize the assumption of independence. The proposed particle filter based data fusion algorithm is applied to experimental NDE data to investigate its feasibility.

  15. On the Reliability of a Solitary Wave Based Transducer to Determine the Characteristics of Some Materials

    PubMed Central

    Deng, Wen; Nasrollahi, Amir; Rizzo, Piervincenzo; Li, Kaiyuan

    2015-01-01

    In the study presented in this article we investigated the feasibility and the reliability of a transducer design for the nondestructive evaluation (NDE) of the stiffness of structural materials. The NDE method is based on the propagation of highly nonlinear solitary waves (HNSWs) along a one-dimensional chain of spherical particles that is in contact with the material to be assessed. The chain is part of a built-in system designed and assembled to excite and detect HNSWs, and to exploit the dynamic interaction between the particles and the material to be inspected. This interaction influences the time-of-flight and the amplitude of the solitary pulses reflected at the transducer/material interface. The results of this study show that certain features of the waves are dependent on the modulus of elasticity of the material and that the built-in system is reliable. In the future the proposed NDE method may provide a cost-effective tool for the rapid assessment of materials’ modulus. PMID:26703617

  16. Towards improved NDE and SHM methodologies incorporating nonlinear structural features

    NASA Astrophysics Data System (ADS)

    Chillara, Vamshi Krishna

    Ultrasound is widely employed in Nondestructive Evaluation (NDE) and Structural Health Monitoring (SHM) applications to detect and characterize damage/defects in materials. In particular, ultrasonic guided waves are considered a foremost candidate for in-situ monitoring applications. Conventional ultrasonic techniques rely on changes/discontinuities in linear elastic material properties, namely the Young's modulus and shear modulus to detect damage. On the other hand, nonlinear ultrasonic techniques that rely on micro-scale nonlinear material/structural behavior are proven to be sensitive to damage induced microstructural changes that precede macro-scale damage and are hence capable of early damage detection. The goal of this thesis is to investigate the capabilities of nonlinear guided waves --- a fusion of nonlinear ultrasonic techniques with the guided wave methodologies for early damage detection. To that end, the thesis focuses on two important aspects of the problem: 1. Wavemechanics - deals with ultrasonic guided wave propagation in nonlinear waveguides; 2. Micromechanics - deals with correlating ultrasonic response with micro-scale nonlinear material behavior. For the development of efficient NDE and SHM methodologies that incorporate nonlinear structural features, a detailed understanding of the above aspects is indispensable. In this thesis, the wavemechanics aspect of the problem is dealt with from both theoretical and numerical standpoints. A generalized theoretical framework is developed to study higher harmonic guided waves in plates. This was employed to study second harmonic guided waves in pipes using a large-radius asymptotic approximation. Second harmonic guided waves in plates are studied from a numerical standpoint. Theoretical predictions are validated and some key aspects of higher harmonic generation in waveguides are outlined. Finally, second harmonic guided waves in plates with inhomogeneous and localized nonlinearities are studied and

  17. Structural assessment of metal foam using combined NDE and FEA

    NASA Astrophysics Data System (ADS)

    Ghosn, Louis J.; Abdul-Aziz, Ali; Young, Philippe G.; Rauser, Richard W.

    2005-05-01

    Metal foams are expected to find use in structural applications where weight is of particular concern, such as space vehicles, rotorcraft blades, car bodies or portable electronic devices. The obvious structural application of metal foam is for light weight sandwich panels, made up of thin solid face sheets and a metallic foam core. The stiffness of the sandwich structure is increased by separating the two face sheets by a light weight foam core. The resulting high-stiffness structure is lighter than that constructed only out of the solid metal material. Since the face sheets carry the applied in-plane and bending loads, the sandwich architecture is a viable engineering concept. However, the metal foam core must resist transverse shear loads and compressive loads while remaining integral with the face sheets. Challenges relating to the fabrication and testing of these metal foam panels remain due to some mechanical properties falling short of their theoretical potential. Theoretical mechanical properties are based on an idealized foam microstructure and assumed cell geometry. But the actual testing is performed on as fabricated foam microstructure. Hence in this study, a high fidelity finite element analysis is conducted on as fabricated metal foam microstructures, to compare the calculated mechanical properties with the idealized theory. The high fidelity geometric models for the FEA are generated using series of 2D CT scans of the foam structure to reconstruct the 3D metal foam geometry. The metal foam material is an aerospace grade precipitation hardened 17-4 PH stainless steel with high strength and high toughness. Tensile, compressive, and shear mechanical properties are deduced from the FEA model and compared with the theoretical values. The combined NDE/FEA provided insight in the variability of the mechanical properties compared to idealized theory.

  18. Advanced defect detection algorithm using clustering in ultrasonic NDE

    NASA Astrophysics Data System (ADS)

    Gongzhang, Rui; Gachagan, Anthony

    2016-02-01

    A range of materials used in industry exhibit scattering properties which limits ultrasonic NDE. Many algorithms have been proposed to enhance defect detection ability, such as the well-known Split Spectrum Processing (SSP) technique. Scattering noise usually cannot be fully removed and the remaining noise can be easily confused with real feature signals, hence becoming artefacts during the image interpretation stage. This paper presents an advanced algorithm to further reduce the influence of artefacts remaining in A-scan data after processing using a conventional defect detection algorithm. The raw A-scan data can be acquired from either traditional single transducer or phased array configurations. The proposed algorithm uses the concept of unsupervised machine learning to cluster segmental defect signals from pre-processed A-scans into different classes. The distinction and similarity between each class and the ensemble of randomly selected noise segments can be observed by applying a classification algorithm. Each class will then be labelled as `legitimate reflector' or `artefacts' based on this observation and the expected probability of defection (PoD) and probability of false alarm (PFA) determined. To facilitate data collection and validate the proposed algorithm, a 5MHz linear array transducer is used to collect A-scans from both austenitic steel and Inconel samples. Each pulse-echo A-scan is pre-processed using SSP and the subsequent application of the proposed clustering algorithm has provided an additional reduction to PFA while maintaining PoD for both samples compared with SSP results alone.

  19. Investigation of inductively coupled ultrasonic transducer system for NDE.

    PubMed

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

    2013-06-01

    Inductive coupling offers a simple solution to wirelessly probe ultrasonic transducers. This paper investigates the theory and feasibility of such an inductively coupled transducer system in the context of nondestructive evaluation (NDE) applications. The noncontact interface is based on electromagnetic coupling between three coils; one of the coils is physically connected to the transducer, the other two are in a separate probing unit, where they are connected to the transmit and receive channels of the instrumentation. The complete system is modeled as a three-port network with the measured impedance of a bonded piezoelectric ceramic disc representing a sensor attached to an arbitrary solid substrate. The developed transmission line model is a function of the physical parameters of the electromagnetic system, such as the number of turns and diameter of each coil, and their separation. This model provides immediate predictions of electrical input impedance and pulse-echo response. The model has been validated experimentally and a sensitivity analysis of the input parameters performed. This has enabled optimization of the various parameters. Inductively coupled transducer systems have been built for both bulk and guided wave examples. By using chirped excitation and baseline subtraction, inspection distance of up to 700 mm is achieved in single-shot, guided-wave pulse-echo mode measurements with a 5 mm separation between the probing coils and transducer coil on an aluminum plate structure. In the bulk wave example, a delamination in an 8.9-mm-thick carbon fiber composite specimen is successfully identified from the changes in the arrival time of a reflected pulse. PMID:25004474

  20. (abstract) Oblique Insonification Ultrasonic NDE of Composite Materials for Space Applications

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

    In recent years, a great deal of research has been exerted to developing NDE methods for the characterization of the material properties of composites as well as other space structural materials. The need for information about such parameters as the elastic properties, density, and thickness are critical to the safe design and operation of such structural materials. Ultrasonics using immersion methods has played an important role in these efforts due to its capability, cost effectiveness, and ease of use. The authors designed a series of ultrasonic oblique insonification experiments in order to develop a practical field applicable NDE method for space structures.

  1. Characterization of Weathering Degradation in Aircraft Polymeric Coatings Using NDE Imaging Techniques

    NASA Astrophysics Data System (ADS)

    Kramb, V. A.; Hoffmann, J. P.; Johnson, J. A.

    2003-03-01

    This paper discusses the current progress in a study of nondestructive inspection methods for monitoring epoxy primer coating degradation under simulated weathering conditions. Characterization of the chemical changes in the coating will be conducted using attenuated total reflection (ATR) — Fourier transform infrared (FTIR) spectroscopy and IR microscopy. The nondestructive evaluation (NDE) methods used to monitor the physical degradation of the polymeric coating include: white light interference microscopy (WLIM), nanoindentation, and scanning acoustic microscopy (SAM). The microscopic images obtained using the NDE methods will be correlated with the measured physical and chemical changes. Artificial weathering of the coated samples was conducted using simulated sunlight exposure (Xenon are lamps), combined with heat and humidity.

  2. Reliability and Confidence.

    ERIC Educational Resources Information Center

    Test Service Bulletin, 1952

    1952-01-01

    Some aspects of test reliability are discussed. Topics covered are: (1) how high should a reliability coefficient be?; (2) two factors affecting the interpretation of reliability coefficients--range of talent and interval between testings; (3) some common misconceptions--reliability of speed tests, part vs. total reliability, reliability for what…

  3. Human Reliability Program Workshop

    SciTech Connect

    Landers, John; Rogers, Erin; Gerke, Gretchen

    2014-05-18

    A Human Reliability Program (HRP) is designed to protect national security as well as worker and public safety by continuously evaluating the reliability of those who have access to sensitive materials, facilities, and programs. Some elements of a site HRP include systematic (1) supervisory reviews, (2) medical and psychological assessments, (3) management evaluations, (4) personnel security reviews, and (4) training of HRP staff and critical positions. Over the years of implementing an HRP, the Department of Energy (DOE) has faced various challenges and overcome obstacles. During this 4-day activity, participants will examine programs that mitigate threats to nuclear security and the insider threat to include HRP, Nuclear Security Culture (NSC) Enhancement, and Employee Assistance Programs. The focus will be to develop an understanding of the need for a systematic HRP and to discuss challenges and best practices associated with mitigating the insider threat.

  4. An Examination of Test-Retest, Alternate Form Reliability, and Generalizability Theory Study of the easyCBM Word and Passage Reading Fluency Assessments: Grade 3. Technical Report #1218

    ERIC Educational Resources Information Center

    Park, Bitnara Jasmine; Anderson, Daniel; Alonzo, Julie; Lai, Cheng-Fei; Tindal, Gerald

    2012-01-01

    This technical report is one in a series of five describing the reliability (test/retest and alternate form) and G-Theory/D-Study research on the easyCBM reading measures, grades 1-5. Data were gathered in the spring of 2011 from a convenience sample of students nested within classrooms at a medium-sized school district in the Pacific Northwest.…

  5. Rod examination gauge

    SciTech Connect

    Bacvinskas, W.S.; Bayer, J.E.; Davis, W.W.; Fodor, G.; Kikta, T.J.; Matchett, R.L.; Nilsen, R.J.; Wilczynski, R.

    1991-12-31

    The present invention is directed to a semi-automatic rod examination gauge for performing a large number of exacting measurements on radioactive fuel rods. The rod examination gauge performs various measurements underwater with remote controlled machinery of high reliability. The rod examination gauge includes instruments and a closed circuit television camera for measuring fuel rod length, free hanging bow measurement, diameter measurement, oxide thickness measurement, cladding defect examination, rod ovality measurement, wear mark depth and volume measurement, as well as visual examination. A control system is provided including a programmable logic controller and a computer for providing a programmed sequence of operations for the rod examination and collection of data.

  6. Magnetic flux leakage-based steel cable NDE and damage visualization on a cable climbing robot

    NASA Astrophysics Data System (ADS)

    Kim, Ju-Won; Lee, Changgil; Park, Seunghee; Lee, Jong Jae

    2012-04-01

    The steel cables in long span bridges such as cable-stayed bridges and suspension bridges are critical members which suspend the load of main girders and bridge floor slabs. Damage of cable members can occur in the form of crosssectional loss caused by fatigue, wear, and fracture, which can lead to structural failure due to concentrated stress in the cable. Therefore, nondestructive examination of steel cables is necessary so that the cross-sectional loss can be detected. Thus, an automated cable monitoring system using a suitable NDE technique and a cable climbing robot is proposed. In this study, an MFL (Magnetic Flux Leakage- based inspection system was applied to monitor the condition of cables. This inspection system measures magnetic flux to detect the local faults (LF) of steel cable. To verify the feasibility of the proposed damage detection technique, an 8-channel MFL sensor head prototype was designed and fabricated. A steel cable bunch specimen with several types of damage was fabricated and scanned by the MFL sensor head to measure the magnetic flux density of the specimen. To interpret the condition of the steel cable, magnetic flux signals were used to determine the locations of the flaws and the level of damage. Measured signals from the damaged specimen were compared with thresholds set for objective decision making. In addition, the measured magnetic flux signal was visualized into a 3D MFL map for convenient cable monitoring. Finally, the results were compared with information on actual inflicted damages to confirm the accuracy and effectiveness of the proposed cable monitoring method.

  7. The scaffold protein Nde1 safeguards the brain genome during S phase of early neural progenitor differentiation

    PubMed Central

    Houlihan, Shauna L; Feng, Yuanyi

    2014-01-01

    Successfully completing the S phase of each cell cycle ensures genome integrity. Impediment of DNA replication can lead to DNA damage and genomic disorders. In this study, we show a novel function for NDE1, whose mutations cause brain developmental disorders, in safeguarding the genome through S phase during early steps of neural progenitor fate restrictive differentiation. Nde1 mutant neural progenitors showed catastrophic DNA double strand breaks concurrent with the DNA replication. This evoked DNA damage responses, led to the activation of p53-dependent apoptosis, and resulted in the reduction of neurons in cortical layer II/III. We discovered a nuclear pool of Nde1, identified the interaction of Nde1 with cohesin and its associated chromatin remodeler, and showed that stalled DNA replication in Nde1 mutants specifically occurred in mid-late S phase at heterochromatin domains. These findings suggest that NDE1-mediated heterochromatin replication is indispensible for neuronal differentiation, and that the loss of NDE1 function may lead to genomic neurological disorders. DOI: http://dx.doi.org/10.7554/eLife.03297.001 PMID:25245017

  8. Fatigue Reliability of Gas Turbine Engine Structures

    NASA Technical Reports Server (NTRS)

    Cruse, Thomas A.; Mahadevan, Sankaran; Tryon, Robert G.

    1997-01-01

    The results of an investigation are described for fatigue reliability in engine structures. The description consists of two parts. Part 1 is for method development. Part 2 is a specific case study. In Part 1, the essential concepts and practical approaches to damage tolerance design in the gas turbine industry are summarized. These have evolved over the years in response to flight safety certification requirements. The effect of Non-Destructive Evaluation (NDE) methods on these methods is also reviewed. Assessment methods based on probabilistic fracture mechanics, with regard to both crack initiation and crack growth, are outlined. Limit state modeling techniques from structural reliability theory are shown to be appropriate for application to this problem, for both individual failure mode and system-level assessment. In Part 2, the results of a case study for the high pressure turbine of a turboprop engine are described. The response surface approach is used to construct a fatigue performance function. This performance function is used with the First Order Reliability Method (FORM) to determine the probability of failure and the sensitivity of the fatigue life to the engine parameters for the first stage disk rim of the two stage turbine. A hybrid combination of regression and Monte Carlo simulation is to use incorporate time dependent random variables. System reliability is used to determine the system probability of failure, and the sensitivity of the system fatigue life to the engine parameters of the high pressure turbine. 'ne variation in the primary hot gas and secondary cooling air, the uncertainty of the complex mission loading, and the scatter in the material data are considered.

  9. Challenges of NDE simulation tool validation, optimization, and utilization for composites

    NASA Astrophysics Data System (ADS)

    Leckey, Cara A. C.; Seebo, Jeffrey P.; Juarez, Peter

    2016-02-01

    Rapid, realistic nondestructive evaluation (NDE) simulation tools can aid in inspection optimization and prediction of inspectability for advanced aerospace materials and designs. NDE simulation tools may someday aid in the design and certification of aerospace components; potentially shortening the time from material development to implementation by industry and government. Furthermore, ultrasound modeling and simulation are expected to play a significant future role in validating the capabilities and limitations of guided wave based structural health monitoring (SHM) systems. The current state-of-the-art in ultrasonic NDE/SHM simulation is still far from the goal of rapidly simulating damage detection techniques for large scale, complex geometry composite components/vehicles containing realistic damage types. Ongoing work at NASA Langley Research Center is focused on advanced ultrasonic simulation tool development. This paper discusses challenges of simulation tool validation, optimization, and utilization for composites. Ongoing simulation tool development work is described along with examples of simulation validation and optimization challenges that are more broadly applicable to all NDE simulation tools. The paper will also discuss examples of simulation tool utilization at NASA to develop new damage characterization methods for composites, and associated challenges in experimentally validating those methods.

  10. ANALYSIS OF EMERGING NDE TECHNIQUES: METHODS FOR EVALUATING AND IMPLEMENTING CONTINUOUS ONLINE MONITORING

    SciTech Connect

    Cumblidge, Stephen E.; Doctor, Steven R.; Bond, Leonard J.; Taylor, Theodore T.; Lupold, Timothy R.; Hull, Amy; Malik, Shah

    2009-08-05

    One of the goals of the program for the proactive management of materials degradation (PMMD) is to manage proactively the in-service degradation of metallic components in aging NPPs. As some forms of degradation, such as stress corrosion cracking, are characterized by a long initiation time followed by a rapid growth phase, new inspection or monitoring technologies may be required. New nondestructive evaluation (NDE) techniques that may be needed include techniques to find stress corrosion cracking (SCC) precursors, on-line monitoring techniques to detect cracks as they initiate and grow, as well as advances in NDE technologies. This paper reports on the first part of the development of a methodology to determine the effectiveness of these emerging NDE techniques for managing metallic degradation. This methodology will draw from experience derived from evaluating techniques that have "emerged" in the past. The methodology will follow five stages: a definition of inspection parameters, a technical evaluation, laboratory testing, round robin testing, and the design of a performance demonstration program. This methodology will formalize the path taken for previous techniques and set a predictable course for future NDE techniques. This paper then applies the expert review section of the methodology to the acoustic emission technique to evaluate the use of acoustic emission in performing continuous online monitoring of reactor components.

  11. Nondestructive evaluation research progress in 1989: Proceedings from the tenth annual EPRI NDE information meeting

    SciTech Connect

    Avioli, M.J. Jr.; Behravesh, M.M.; Gehl, S.M.; Liu, S.N.; Stein, J.; Welty, C.S. )

    1990-06-01

    The increasing cost of equipment for power generating plants and the potential increases in productivity and safety available through rapidity developing nondestructive evaluation (NDE) technology led EPRI to initiate a Nondestructive Evaluation Program in 1974. To date, the major focus has been on light water reactor (LWR) inspection problems; however, increased application to other systems is now under way. This report presents a comprehensive review of the EPRI effort in the NDE area. Most of the report consists of contractor-supplied progress reports on each current project. An organizational plan of the program is presented in overview. In addition, organization from several viewpoints is presented, e.g., in-service inspection operators, R D personnel, and utility representatives. As the eleventh in a planned series of annual progress reports of EPRI-funded NDE activities, this report also serves as the proceedings of the Tenth Annual EPRI NDE Information Meeting held in Palo Alto, California, on November 14-15, 1989. It summarizes significant progress made since the previous EPRI Special Report NP-6075-SR was issued in May 1989. Section 1 contains information about the program organization, and the sections that follow contain contractor-supplied progress reports on each current project. The progress reports are grouped by plant components -- pipe and nozzle, pressure vessel, and boilers and steam generators. In addition, Part 5 is devoted to discussions of technology transfer. The individual papers have been cataloged separately.

  12. Similarities and differences in bare concrete deck deterioration curves from multi NDE technology surveys

    NASA Astrophysics Data System (ADS)

    Kim, Jinyoung; Gucunski, Nenad; Dinh, Kien

    2016-04-01

    Reinforced concrete decks are in most cases the fastest deteriorating components of a bridge due to the multitude of influencing factors: direct traffic loading and environmental effects, maintenance activities (salting), etc. Among many deterioration types, corrosion-induced deterioration is the most common problem in reinforced concrete decks. The study concentrates on the condition assessment of bridge decks using complementary NDE techniques. The assessment has three main components: assessment of corrosive environment and corrosion processes, and assessment with respect to the deck delamination. The study concentrates on a complementary use of five NDE techniques: impact echo (IE) to detect and characterize delamination, ground penetrating radar (GPR) to describe the corrosive environment and detect delamination, and electrical resistivity (ER) to estimate the corrosion rate by measuring concrete resistivity. The ability of the NDE methods to objectively characterize deterioration progression is illustrated by the results from NDE surveys of 10 bridges of different ages in New Jersey during a period of one year. The deterioration progression is illustrated by condition maps and condition indices. As demonstrated in the paper, multiple deterioration models are developed utilizing the proposed methodology, which shows high potential for development of more realistic deterioration and life cycle cost models for bridge decks.

  13. Experimental Enhancements of LLW Dispersion Data Acquisition and Implementation Challenges to NDE of Composites

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Y.; Liu, S. S.

    1999-01-01

    The Leaky Lamb Wave (LLW) technique is approaching a maturity level that is making it an attractive quantitative NDE tool for composites and bonded joints. Since it was first observed in 1982, the phenomenon has been studied extensively, particularly in composite materials.

  14. Space environmental effects, materials, and NDE/NDI presentation to SSTAC/ARTS Review Committee

    NASA Technical Reports Server (NTRS)

    Venneri, Samuel L.

    1991-01-01

    Viewgraphs are presented on space environmental effects, materials, and NDE/NDI for the integrated technology plan for the civil space program. Topics covered include: space materials; space durable polymers; simulated space environmental effects; space radiation effects on polymer matrix composites; advanced coatings for spacecraft; Long Duration Exposure Facility; meteoroid and debris velocity distribution; and space environmental effects.

  15. Time-Domain Terahertz Computed Axial Tomography NDE System

    NASA Technical Reports Server (NTRS)

    Zimdars, David

    2012-01-01

    NASA has identified the need for advanced non-destructive evaluation (NDE) methods to characterize aging and durability in aircraft materials to improve the safety of the nation's airline fleet. 3D THz tomography can play a major role in detection and characterization of flaws and degradation in aircraft materials, including Kevlar-based composites and Kevlar and Zylon fabric covers for soft-shell fan containment where aging and durability issues are critical. A prototype computed tomography (CT) time-domain (TD) THz imaging system has been used to generate 3D images of several test objects including a TUFI tile (a thermal protection system tile used on the Space Shuttle and possibly the Orion or similar capsules). This TUFI tile had simulated impact damage that was located and the depth of damage determined. The CT motion control gan try was designed and constructed, and then integrated with a T-Ray 4000 control unit and motion controller to create a complete CT TD-THz imaging system prototype. A data collection software script was developed that takes multiple z-axis slices in sequence and saves the data for batch processing. The data collection software was integrated with the ability to batch process the slice data with the CT TD-THz image reconstruction software. The time required to take a single CT slice was decreased from six minutes to approximately one minute by replacing the 320 ps, 100-Hz waveform acquisition system with an 80 ps, 1,000-Hz waveform acquisition system. The TD-THZ computed tomography system was built from pre-existing commercial off-the-shelf subsystems. A CT motion control gantry was constructed from COTS components that can handle larger samples. The motion control gantry allows inspection of sample sizes of up to approximately one cubic foot (.0.03 cubic meters). The system reduced to practice a CT-TDTHz system incorporating a COTS 80- ps/l-kHz waveform scanner. The incorporation of this scanner in the system allows acquisition of 3D

  16. Developing NDE Techniques for Large Cryogenic Tanks - Year 2 Report

    NASA Technical Reports Server (NTRS)

    Arens, Ellen; youngquist, Robert; McFall, Judith; Simmons, Stephen

    2010-01-01

    The Shuttle Program requires very large cryogenic ground storage tanks in which to store liquid oxygen and hydrogen. The existing Launch Complex-39 Pad tanks, which will be passed onto future launch programs, are over 40 years old and have received minimal refurbishment and only external inspections over the years. The majority of the structure is inaccessible without a full system drain of cryogenic liquid and insulation in the annular region. It was previously thought that there was a limit to the number of temperature cycles that the tanks could handle due to possible insulation compaction before undergoing a costly and time consuming complete overhaul; therefore the tanks were not drained and performance issues with these tanks, specifically the Pad B LH2 tank, were accepted. There is a need and an opportunity, as the Shuttle program ends and work to upgrade the launch pad progresses, to develop innovative non-destructive evaluation (NDE) techniques to analyze the current tanks. Techniques are desired that can aid in determining the extent of refurbishment required to keep the tanks in service for another 20+ years. A non-destructive technique would also be a significant aid in acceptance testing of new and refurbished tanks, saving significant time and money, if corrective actions can be taken before cryogen is introduced to the systems. Year one of this project concentrated on analysis of the current tanks located at LC-39 while cryogen was present. Year two of this project concentrated on analysis of detectable thermal variations on the outer surface of the tanks as the cryogen was drained and the inner vessel warmed to ambient conditions. Two techniques have been deployed in the field to monitor the tank. The first consisted of a displacement sensor to monitor for any expansions at the base of the tank during warm-up that could indicate a compaction issue with the insulation. The second technique was continued thermal monitoring of the tank through and

  17. Tank Inspection NDE Results for Fiscal Year 2014, Waste Tanks 26, 27, 28 and 33

    SciTech Connect

    Elder, J.; Vandekamp, R.

    2014-09-29

    Ultrasonic nondestructive examinations (NDE) were performed on waste storage tanks 26, 27, 28 and 33 at the Savannah River Site as a part of the “In-Service Inspection (ISI) Program for High Level Waste Tanks.” No reportable conditions were identified during these inspections. The results indicate that the implemented corrosion control program continues to effectively mitigate corrosion in the SRS waste tanks. Ultrasonic inspection (UT) is used to detect general wall thinning, pitting and interface attack, as well as vertically oriented cracks through inspection of an 8.5 inch wide strip extending over the accessible height of the primary tank wall and accessible knuckle regions. Welds were also inspected in tanks 27, 28 and 33 with no reportable indications. In a Type III/IIIA primary tank, a complete vertical strip includes scans of five plates (including knuckles) so five “plate/strips” would be completed at each vertical strip location. In FY 2014, a combined total of 79 plate/strips were examined for thickness mapping and crack detection, equating to over 45,000 square inches of area inspected on the primary tank wall. Of the 79 plate/strips examined in FY 2014 all but three have average thicknesses that remain at or above the construction minimum thickness which is nominal thickness minus 0.010 inches. There were no service induced reportable thicknesses or cracking encountered. A total of 2 pits were documented in 2014 with the deepest being 0.032 inches deep. One pit was detected in Tank 27 and one in Tank 33. No pitting was identified in Tanks 26 or 28. The maximum depth of any pit encountered in FY 2014 is 5% of nominal thickness, which is less than the minimum reportable criteria of 25% through-wall for pitting. In Tank 26 two vertical strips were inspected, as required by the ISI Program, due to tank conditions being outside normal chemistry controls for more than 3 months. Tank 28 had an area of localized thinning on the exterior wall of the

  18. Measuring acuity of the approximate number system reliably and validly: the evaluation of an adaptive test procedure

    PubMed Central

    Lindskog, Marcus; Winman, Anders; Juslin, Peter; Poom, Leo

    2013-01-01

    Two studies investigated the reliability and predictive validity of commonly used measures and models of Approximate Number System acuity (ANS). Study 1 investigated reliability by both an empirical approach and a simulation of maximum obtainable reliability under ideal conditions. Results showed that common measures of the Weber fraction (w) are reliable only when using a substantial number of trials, even under ideal conditions. Study 2 compared different purported measures of ANS acuity as for convergent and predictive validity in a within-subjects design and evaluated an adaptive test using the ZEST algorithm. Results showed that the adaptive measure can reduce the number of trials needed to reach acceptable reliability. Only direct tests with non-symbolic numerosity discriminations of stimuli presented simultaneously were related to arithmetic fluency. This correlation remained when controlling for general cognitive ability and perceptual speed. Further, the purported indirect measure of ANS acuity in terms of the Numeric Distance Effect (NDE) was not reliable and showed no sign of predictive validity. The non-symbolic NDE for reaction time was significantly related to direct w estimates in a direction contrary to the expected. Easier stimuli were found to be more reliable, but only harder (7:8 ratio) stimuli contributed to predictive validity. PMID:23964256

  19. Stochastic optimization techniques for NDE of bridges using vibration signatures

    NASA Astrophysics Data System (ADS)

    Yi, Jin-Hak; Feng, Maria Q.

    2003-08-01

    A baseline model updating is the first step for the model-based non destructive evaluation for civil infrastructures. Many researches have been drawn to obtain a more reliable baseline model. In this study, heuristic optimization techniques (or called as stochastic optimization techniques) including the genetic algorithm, the simulated annealing, and the tabu search, were have been investigated for constructing the reliable baseline model for an instrumented new highway bridge, and also were compared with the result of conventional sensitivity method. The preliminary finite element model of the bridge was successfully updated to a baseline model based on measured vibration data.

  20. Reliability model generator

    NASA Technical Reports Server (NTRS)

    McMann, Catherine M. (Inventor); Cohen, Gerald C. (Inventor)

    1991-01-01

    An improved method and system for automatically generating reliability models for use with a reliability evaluation tool is described. The reliability model generator of the present invention includes means for storing a plurality of low level reliability models which represent the reliability characteristics for low level system components. In addition, the present invention includes means for defining the interconnection of the low level reliability models via a system architecture description. In accordance with the principles of the present invention, a reliability model for the entire system is automatically generated by aggregating the low level reliability models based on the system architecture description.

  1. NONDESTRUCTIVE EXAMINATION OF FUEL PLATES FOR THE RERTR FUEL DEVELOPMENT EXPERIMENTS

    SciTech Connect

    N.E. Woolstenhulme; S.C. Taylor; G.A. Moore; D.M. Sterbentz

    2012-09-01

    Nuclear fuel is the core component of reactors that is used to produce the neutron flux required for irradiation research purposes as well as commercial power generation. The development of nuclear fuels with low enrichments of uranium is a major endeavor of the RERTR program. In the development of these fuels, the RERTR program uses nondestructive examination (NDE) techniques for the purpose of determining the properties of nuclear fuel plate experiments without imparting damage or altering the fuel specimens before they are irradiated in a reactor. The vast range of properties and information about the fuel plates that can be characterized using NDE makes them highly useful for quality assurance and for analyses used in modeling the behavior of the fuel while undergoing irradiation. NDE is also particularly useful for creating a control group for post-irradiation examination comparison. The two major categories of NDE discussed in this paper are X-ray radiography and ultrasonic testing (UT) inspection/evaluation. The radiographic scans are used for the characterization of fuel meat density and homogeneity as well as the determination of fuel location within the cladding. The UT scans are able to characterize indications such as voids, delaminations, inclusions, and other abnormalities in the fuel plates which are generally referred to as debonds as well as to determine the thickness of the cladding using ultrasonic acoustic microscopy methods. Additionally, the UT techniques are now also being applied to in-canal interim examination of fuel experiments undergoing irradiation and the mapping of the fuel plate surface profile to determine fuel swelling. The methods used to carry out these NDE techniques, as well as how they operate and function, are described along with a description of which properties are characterized.

  2. Cloning of the promoter of NDE1, a gene implicated in psychiatric and neurodevelopmental disorders through copy number variation.

    PubMed

    Bradshaw, N J

    2016-06-01

    Copy number variation at 16p13.11 has been associated with a range of neurodevelopmental and psychiatric conditions, with duplication of this region being more common in individuals with schizophrenia. A prominent candidate gene within this locus is NDE1 (Nuclear Distribution Element 1) given its known importance for neurodevelopment, previous associations with mental illness and its well characterized interaction with the Disrupted in Schizophrenia 1 (DISC1) protein. In order to accurately model the effect of NDE1 duplication, it is important to first gain an understanding of how the gene is expressed. The complex promoter system of NDE1, which produces three distinct transcripts, each encoding for the same full-length NDE1 protein (also known as NudE), was therefore cloned and tested in human cell lines. The promoter for the longest of these three NDE1 transcripts was found to be responsible for the majority of expression in these systems, with its extended 5' untranslated region (UTR) having a limiting effect on its expression. These results thus highlight and clone the promoter elements required to generate systems in which the NDE1 protein is exogenously expressed under its native promoter, providing a biologically relevant model of 16p13.11 duplication in major mental illness. PMID:26975893

  3. Can There Be Reliability without "Reliability?"

    ERIC Educational Resources Information Center

    Mislevy, Robert J.

    2004-01-01

    An "Educational Researcher" article by Pamela Moss (1994) asks the title question, "Can there be validity without reliability?" Yes, she answers, if by reliability one means "consistency among independent observations intended as interchangeable" (Moss, 1994, p. 7), quantified by internal consistency indices such as KR-20 coefficients and…

  4. HELIOS Critical Design Review: Reliability

    NASA Technical Reports Server (NTRS)

    Benoehr, H. C.; Herholz, J.; Prem, H.; Mann, D.; Reichert, L.; Rupp, W.; Campbell, D.; Boettger, H.; Zerwes, G.; Kurvin, C.

    1972-01-01

    This paper presents Helios Critical Design Review Reliability form October 16-20, 1972. The topics include: 1) Reliability Requirement; 2) Reliability Apportionment; 3) Failure Rates; 4) Reliability Assessment; 5) Reliability Block Diagram; and 5) Reliability Information Sheet.

  5. Web Awards: Are They Reliable?

    ERIC Educational Resources Information Center

    Everhart, Nancy; McKnight, Kathleen

    1997-01-01

    School library media specialists recommend quality Web sites to children based on evaluations and Web awards. This article examines three types of Web awards and who grants them, suggests ways to determine their reliability, and discusses specific award sites. Includes a bibliography of Web sites. (PEN)

  6. Neural-Net Based Optical NDE Method for Structural Health Monitoring

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.; Weiland, Kenneth E.

    2003-01-01

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

  7. Development of NDE to monitor bond degradation in aircraft honeycomb components

    NASA Astrophysics Data System (ADS)

    Bowles, Susan J.; Scala, Christine M.

    1999-12-01

    This paper presents results of recent research at DSTO Aeronautical and Maritime Research Laboratory to develop NDE techniques to assess bond degradation in metal-skin honeycomb and composite skin honeycomb control surfaces. In particular, it covers the detection of fillet bond failure where the honeycomb core and adhesive separate. Realistic fillet bond failure specimens, one of which had only 20% of the good bond strength, were generated by the application of spray-release agent to the honeycomb. 20MHz ultrasonic pulse-echo imaging was successfully used to detect fillet bond failure in these specimens. This technique was successful in detecting defined areas of fillet bond failure for a range of skin type and thickness Promising results were also obtained for the application to actual components, whilst also highlighting effects due to the presence of repairs. Further work will involve the evaluation of a range of other NDE methods to the detection and sizing of fillet bond failure.

  8. Comparison of three electromagnetic NDE procedures using realistic feedwater heater mock-ups

    SciTech Connect

    Krzywosz, K.; Cagle, L. Jr. )

    1993-02-01

    Three electromagnetic NDE techniques are currently available to evaluate the tubing integrity of high-pressure feedwater heaters. They are remote-field eddy current, magnetically biased partial saturation eddy current, and flux leakage. To evaluate the performance of each technique, tubes containing filed-induced flaws were removed from retired bundles, characterized both destructively and nondestructively, and assembled into realistic mock-ups with tube support plates at their original locations. The assembled mockups were tested by vendors using three different inspection techniques. Each procedure was evaluated for its ability to detect and size field-induced flaws. Both flaw detection and NDE estimates were compared with known ground truth.' Based on the comparative test results, the most suitable inspection procedures evaluated to date for flaw detection and sizing were discerned. The evaluated high-pressure feedwater heater was made of SA 556-C2 carbon steel (CS) tubing.

  9. Automotive Lightweight Materials: the Roles of Nde in Bringing New Materials Into Production

    NASA Astrophysics Data System (ADS)

    Dasch, Cameron J.

    2008-02-01

    The automotive industry is in the midst of a time of tremendous change. There is an almost perfect storm of changing governmental and market requirements seeking much higher fuel economy, low or no carbon dioxide emissions, and much higher crash and safety performance. Moreover, this occurs in a globe-spanning market that has more low-cost manufacturers than ever before. This confluence of factors leads to new vehicles with many new types of powertrains having unprecedented power densities and highly-engineered body structures with many new materials and joining methods. These are being turned out with shorter lead times, higher quality requirements, and continuous cost pressures. This talk will review the role in NDE in bringing new materials and processes to market, some of the applications in production, and to highlight some of the current NDE needs driven by these forces on the automotive industry.

  10. Directed Design of Experiments (DOE) for Determining Probability of Detection (POD) Capability of NDE Systems (DOEPOD)

    NASA Technical Reports Server (NTRS)

    Generazio, Ed

    2007-01-01

    This viewgraph presentation reviews some of the issues that people who specialize in Non destructive evaluation (NDE) have with determining the statistics of the probability of detection. There is discussion of the use of the binominal distribution, and the probability of hit. The presentation then reviews the concepts of Directed Design of Experiments for Validating Probability of Detection of Inspection Systems (DOEPOD). Several cases are reviewed, and discussed. The concept of false calls is also reviewed.

  11. NDE of spacecraft materials using 3D Compton backscatter x-ray imaging

    NASA Astrophysics Data System (ADS)

    Burke, E. R.; Grubsky, V.; Romanov, V.; Shoemaker, K.

    2016-02-01

    We present the results of testing of the NDE performance of a Compton Imaging Tomography (CIT) system for single-sided, penetrating 3D inspection. The system was recently developed by Physical Optics Corporation (POC) and delivered to NASA for testing and evaluation. The CIT technology is based on 3D structure mapping by collecting the information on density profiles in multiple object cross sections through hard x-ray Compton backscatter imaging. The individual cross sections are processed and fused together in software, generating a 3D map of the density profile of the object which can then be analyzed slice-by-slice in x, y, or z directions. The developed CIT scanner is based on a 200-kV x-ray source, flat-panel x-ray detector (FPD), and apodized x-ray imaging optics. The CIT technology is particularly well suited to the NDE of lightweight aerospace materials, such as the thermal protection system (TPS) ceramic and composite materials, micrometeoroid and orbital debris (MMOD) shielding, spacecraft pressure walls, inflatable habitat structures, composite overwrapped pressure vessels (COPVs), and aluminum honeycomb materials. The current system provides 3D localization of defects and features with field of view 20x12x8 cm3 and spatial resolution ˜2 mm. In this paper, we review several aerospace NDE applications of the CIT technology, with particular emphasis on TPS. Based on the analysis of the testing results, we provide recommendations for continued development on TPS applications that can benefit the most from the unique capabilities of this new NDE technology.

  12. Structural analysis of an NDE-inspected carbon-carbon component

    NASA Technical Reports Server (NTRS)

    Striz, A. G.; Cruse, G.; Kline, R. A.; Madaras, E. I.

    1992-01-01

    In this research, it is demonstrated that the integration of nondestructive evaluation with the finite element method (a quantitative NDE/FEM approach) can be used for analysis and behavior prediction of advanced materials, such as fiber composites, after processing and during in-service testing. First, stress, strain, and energy data were calculated by the finite element method for square plates with a 10 percent difference in the material properties between specified segments, i.e., between the center and the outside section or between two halves of the plate. This demonstrated the efficiency of the method in predicting variations in the structural behavior based on small material property differences. Then, finite element analyses and actual axial compression tests were performed on a Space Shuttle brake stator made from woven carbon-carbon composites. The material properties used in the numerical modeling of the stator were previously characterized at a large number of points on the component by quantitative NDE-procedures, i.e., ultrasonics and radiography. The results from the experimental compressive loading tests were used to verify the NDE/FEM results. Good agreement was found for most parameters.

  13. An interaction between NDE1 and high birth weight increases schizophrenia susceptibility.

    PubMed

    Wegelius, Asko; Pankakoski, Maiju; Tomppo, Liisa; Lehto, Ulriika; Lönnqvist, Jouko; Suvisaari, Jaana; Paunio, Tiina; Hennah, William

    2015-12-15

    Pre- and perinatal environmental factors have been shown to increase schizophrenia risk particularly when combined with genetic liability. The investigation of specific gene environment interactions in the etiology of psychiatric disorders has gained momentum. We used multivariate GEE regression modeling to investigate the interaction between genes of the DISC1 pathway and birth weight, in relation to schizophrenia susceptibility in a Finnish schizophrenia family cohort. The study sample consisted of 457 subjects with both genotype and birth weight information. Gender and place of birth were adjusted for in the models. We found a significant interaction between birth weight and two NDE1 markers in relation to increased schizophrenia risk: a four SNP haplotype spanning NDE1 (b=1.26, SE=0.5, p=0.012) and one of its constituent SNPs rs4781678 (b=1.33, SE=0.51, p=0.010). Specifically, high birth weight (>4000g) was associated with increased schizophrenia risk among subjects homozygous for the previously identified risk alleles. The study was based on a family study sample with high genetic loading for schizophrenia and thus our findings cannot directly be generalized as representing the general population. Our results suggest that the functions mediated by NDE1 during the early stages of neurodevelopment are susceptible to the additional disruptive effects of pre- and perinatal environmental factors associated with high birth weight, augmenting schizophrenia susceptibility. PMID:26350705

  14. A Load-based Micro-indentation Technique for Mechanical Property and NDE Evaluation

    SciTech Connect

    Bruce S. Kang; Chuanyu Feng; Jared M. Tannenbaum; M.A. Alvin

    2009-06-04

    A load-based micro-indentation technique has been developed for evaluating mechanical properties of materials. Instead of using measured indentation depth or contact area as a necessary parameter, the new technique is based on the indentation load, coupled with a multiple-partial unloading procedure for mechanical property evaluation. The proposed load-based micro-indentation method is capable of determining Young’s modulus of metals, superalloys, and single crystal matrices, and stiffness of coated material systems with flat, tubular, or curved architectures. This micro-indentation technique can be viewed as a viable non-destructive evaluation (NDE) technique for determining as-manufactured and process-exposed metal, superalloy, single crystal, and TBC-coated material properties. Based on this technique, several bond coated substrates were tested at various stages of thermal cycles. The time-series evaluation of test material surface stiffness reveals the status of coating strength without any alternation of the coating surface, making it a true time-series NDE investigation. The microindentation test results show good correlation with post mortem microstructural analyses. This technique also shows promise for the development of a portable instrument for on-line, in-situ NDE and mechanical properties measurement of structural components.

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

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  17. Automated metrology and NDE measurements for increased throughput in aerospace component manufacture

    NASA Astrophysics Data System (ADS)

    MacLeod, Charles N.; Pierce, S. Gareth; Morozov, Maxim; Summan, Rahul; Dobie, Gordon; McCubbin, Paul; McCubbin, Coreen; Dearie, Scott; Munro, Gavin

    2015-03-01

    Composite materials, particularly Carbon-Fibre-Reinforced Polymer (CFRP), find extensive use in construction of modern airframe structures. Quality and conformance checks can be a serious limitation on production throughput in aerospace manufacturing. Traditionally Non-Destructive Evaluation (NDE) and metrology measurements are undertaken at different stages of a product manufacture cycle using specific dedicated equipment and personnel. However, since both processes involve direct interaction with the component's surface, an opportunity exists to combine these to potentially reduce overall cycle time. In addition when considering moves towards automation of both inspection processes, it is clear that measured metrology data is an essential input parameter to the automated NDE workflow. The authors present the findings of a proof of concept combined sub-scale NDE and Metrology demonstrator cell for aerospace components. Permitting a maximum part area size of 3 × 1 m2, KUKA KR5 6 degree of freedom robotic manipulators were utilised to deploy two inspection payloads. Firstly automated non-contact photogrammetric metrology measurement was employed to inspect the structure for conformance of dimension in relation to reference designs (available from CAD). Secondly automated phased array technology was deployed to inspect and produce ultrasonic thickness mapping of components of nominal 20mm thickness. Parameters such as overall cycle time, part dimensional accuracy, robotic path accuracy and data registration are assessed in the paper to highlight both the current state of the art performance available and the future direction of required research focus.

  18. Structural Analysis of Composite Flywheels: an Integrated NDE and FEM Approach

    NASA Technical Reports Server (NTRS)

    Abdul-Aziz, Ali; Baaklini, George; Trudell, Jeffrey

    2001-01-01

    A structural assessment by integrating finite-element methods (FEM) and a nondestructive evaluation (NDE) of two flywheel rotor assemblies is presented. Composite rotor A is pancake-like with a solid hub design, and composite rotor B is cylindrical with a hollow hub design. Detailed analyses under combined centrifugal and interference-fit loading are performed. Two- and three-dimensional stress analyses and two-dimensional fracture mechanics analyses are conducted. A comparison of the structural analysis results obtained with those extracted via NDE findings is reported. Contact effects due to press-fit conditions are evaluated. Stress results generated from the finite-element analyses were corroborated with the analytical solution. Cracks due to rotational loading up to 48,000 rpm for rotor A and 34,000 rpm for rotor B were successfully imaged with NDE and predicted with FEM and fracture mechanics analyses. A procedure that extends current structural analysis to a life prediction tool is also defined.

  19. PRELIMINARY ASSESSMENT OF NDE METHODS ON INSPECTION OF HDPE BUTT FUSION PIPING JOINTS FOR LACK OF FUSION WITH VALIDATION FROM MECHANICAL TESTING

    SciTech Connect

    Crawford, Susan L.; Doctor, Steven R.; Cinson, Anthony D.; Watts, Michael W.; Moran, Traci L.; Anderson, Michael T.

    2010-07-22

    Studies at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, are being conducted to evaluate nondestructive examinations (NDE) coupled with mechanical testing of butt fusion joints in high density polyethylene (HDPE) pipe for assessing lack of fusion. The work provides information to the United States Nuclear Regulatory Commission (NRC) on the effectiveness of volumetric inspection techniques of HDPE butt fusion joints in Section III, Division 1, Class 3, buried piping systems in nuclear power plants. This paper describes results from preliminary assessments using ultrasonic and microwave nondestructive techniques and mechanical testing with the high speed tensile impact test and the bend test for determining joint integrity. A series of butt joints were fabricated in 3408, 12 inch (30.5 cm) IPS DR-11 HDPE material by varying the fusion parameters to create good joints and joints containing a range of lack of fusion conditions. Six of these butt joints were volumetrically examined with time of flight diffraction (TOFD), phased array (PA) ultrasound, and the Evisive microwave system. The outer diameter (OD) weld beads were removed for microwave evaluation and the pipes ultrasonically re-evaluated. In two of the six pipes both the outer and inner diameter (ID) weld beads were removed and the pipe joints re-evaluated. Several of the pipes were sectioned and the joints destructively evaluated with the following techniques: high speed tensile test, bend test, and focused immersion ultrasound on a joint section removed from the pipe coupled with slicing through the joint and examining the revealed surfaces. The fusion parameters, nondestructive, and destructive evaluation results will be correlated to validate the effectiveness of what each NDE technology detects and what each does not detect. This is an initial limited study which will aid in identifying key future work.

  20. Instrumentation, Monitoring and NDE for New Fast Reactors

    SciTech Connect

    Bond, Leonard J.; Doctor, Steven; Bunch, Kyle; Good, Morris; Waltar, Alan E.

    2007-07-01

    The Global Nuclear Energy Partnership (GNEP) will require the development of actinide transmutation, which can most effectively be accomplished in a fast-spectrum reactor. To achieve higher standards of safety and reliability, operate with longer intervals between outages, and achieve high operating capacity factors, new instrumentation and on-line monitoring capabilities will be required-- during both fabrication and operation. This paper reports parts of a knowledge capture and technology state-of-the-art assessment for fast-reactor instrumentation and controls, monitoring and diagnostics. (authors)

  1. Modelling NDE pulse-echo inspection of misorientated planar rough defects using an elastic finite element method

    NASA Astrophysics Data System (ADS)

    Pettit, J. R.; Walker, A. E.; Lowe, M. J. S.

    2015-03-01

    Pulse-echo ultrasonic NDE examination of large pressure vessel forgings is a design and construction code requirement in the power generation industry. Such inspections aim to size and characterise potential defects that may have formed during the forging process. Typically these defects have a range of orientations and surface roughnesses which can greatly affect ultrasonic wave scattering behaviour. Ultrasonic modelling techniques can provide insight into defect response and therefore aid in characterisation. However, analytical approaches to solving these scattering problems can become inaccurate, especially when applied to increasingly complex defect geometries. To overcome these limitations a elastic Finite Element (FE) method has been developed to simulate pulse-echo inspections of embedded planar defects. The FE model comprises a significantly reduced spatial domain allowing for a Monte-Carlo based approach to consider multiple realisations of defect orientation and surface roughness. The results confirm that defects aligned perpendicular to the path of beam propagation attenuate ultrasonic signals according to the level of surface roughness. However, for defects orientated away from this plane, surface roughness can increase the magnitude of the scattered component propagating back along the path of the incident beam. This study therefore highlights instances where defect roughness increases the magnitude of ultrasonic scattered signals, as opposed to attenuation which is more often assumed.

  2. Modelling NDE pulse-echo inspection of misorientated planar rough defects using an elastic finite element method

    SciTech Connect

    Pettit, J. R.; Lowe, M. J. S.; Walker, A. E.

    2015-03-31

    Pulse-echo ultrasonic NDE examination of large pressure vessel forgings is a design and construction code requirement in the power generation industry. Such inspections aim to size and characterise potential defects that may have formed during the forging process. Typically these defects have a range of orientations and surface roughnesses which can greatly affect ultrasonic wave scattering behaviour. Ultrasonic modelling techniques can provide insight into defect response and therefore aid in characterisation. However, analytical approaches to solving these scattering problems can become inaccurate, especially when applied to increasingly complex defect geometries. To overcome these limitations a elastic Finite Element (FE) method has been developed to simulate pulse-echo inspections of embedded planar defects. The FE model comprises a significantly reduced spatial domain allowing for a Monte-Carlo based approach to consider multiple realisations of defect orientation and surface roughness. The results confirm that defects aligned perpendicular to the path of beam propagation attenuate ultrasonic signals according to the level of surface roughness. However, for defects orientated away from this plane, surface roughness can increase the magnitude of the scattered component propagating back along the path of the incident beam. This study therefore highlights instances where defect roughness increases the magnitude of ultrasonic scattered signals, as opposed to attenuation which is more often assumed.

  3. Ear examination

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/003340.htm Ear examination To use the sharing features on this page, ... ear References King EF, Couch ME. History, physical examination, and the preoperative evaluation. In: Flint PW, Haughey ...

  4. Reliability computation from reliability block diagrams

    NASA Technical Reports Server (NTRS)

    Chelson, P. O.; Eckstein, R. E.

    1971-01-01

    A method and a computer program are presented to calculate probability of system success from an arbitrary reliability block diagram. The class of reliability block diagrams that can be handled include any active/standby combination of redundancy, and the computations include the effects of dormancy and switching in any standby redundancy. The mechanics of the program are based on an extension of the probability tree method of computing system probabilities.

  5. Power electronics reliability analysis.

    SciTech Connect

    Smith, Mark A.; Atcitty, Stanley

    2009-12-01

    This report provides the DOE and industry with a general process for analyzing power electronics reliability. The analysis can help with understanding the main causes of failures, downtime, and cost and how to reduce them. One approach is to collect field maintenance data and use it directly to calculate reliability metrics related to each cause. Another approach is to model the functional structure of the equipment using a fault tree to derive system reliability from component reliability. Analysis of a fictitious device demonstrates the latter process. Optimization can use the resulting baseline model to decide how to improve reliability and/or lower costs. It is recommended that both electric utilities and equipment manufacturers make provisions to collect and share data in order to lay the groundwork for improving reliability into the future. Reliability analysis helps guide reliability improvements in hardware and software technology including condition monitoring and prognostics and health management.

  6. Human Reliability Program Overview

    SciTech Connect

    Bodin, Michael

    2012-09-25

    This presentation covers the high points of the Human Reliability Program, including certification/decertification, critical positions, due process, organizational structure, program components, personnel security, an overview of the US DOE reliability program, retirees and academia, and security program integration.

  7. NONDESTRUCTIVE EXAMINATION OF PLUTONIUM-BEARING MATERIAL CONTAINERS

    SciTech Connect

    Yerger, L.; Mcclard, J.; Traver, L.; Grim, T.

    2010-02-01

    The first nondestructive examination (NDE) of 3013-type containers as part of the Department of Energy's (DOE's) Integrated Surveillance Program (ISP) was performed in February, 2005. Since that date 280 NDE surveillances on 255 containers have been conducted. These containers were packaged with plutonium-bearing materials at multiple DOE sites. The NDE surveillances were conducted at Hanford, Lawrence Livermore National Laboratory (LLNL), and Savannah River Site (SRS). These NDEs consisted of visual inspection, mass verification, radiological surveys, prompt gamma analysis, and radiography. The primary purpose of performing NDE surveillances is to determine if there has been a significant pressure buildup inside the inner 3013 container. This is done by measuring the lid deflection of the inner 3013 container using radiography images. These lid deflection measurements are converted to pressure measurements to determine if a container has a pressure of a 100 psig or greater. Making this determination is required by Surveillance and Monitoring Plan (S&MP). All 3013 containers are designed to withstand at least 699 psig as specified by DOE-STD-3013. To date, all containers evaluated have pressures under 50 psig. In addition, the radiography is useful in evaluating the contents of the 3013 container as well as determining the condition of the walls of the inner 3013 container and the convenience containers. The radiography has shown no signs of degradation of any container, but has revealed two packaging anomalies. Quantitative pressure measurements based on lid deflections, which give more information than the 'less than or greater than 100 psig' (pass/fail) data are also available for many containers. Statistical analyses of the pass/fail data combined with analysis of the quantitative data show that it is extremely unlikely that any container in the population of 3013 containers considered in this study (e.g., containers packaged according to the DOE-STD-3013 by

  8. Reliable Design Versus Trust

    NASA Technical Reports Server (NTRS)

    Berg, Melanie; LaBel, Kenneth A.

    2016-01-01

    This presentation focuses on reliability and trust for the users portion of the FPGA design flow. It is assumed that the manufacturer prior to hand-off to the user tests FPGA internal components. The objective is to present the challenges of creating reliable and trusted designs. The following will be addressed: What makes a design vulnerable to functional flaws (reliability) or attackers (trust)? What are the challenges for verifying a reliable design versus a trusted design?

  9. Reliability reporting practices in rape myth research.

    PubMed

    Buhi, Eric R

    2005-02-01

    A number of school-based programs address sexual violence by focusing on adolescents' attitudes about rape or acceptance of rape myths. However, many problems exist in the literature regarding measurement of rape myth acceptance, including issues of reliability and validity. This paper addresses measurement reliability issues and reviews reliability reporting practices of studies using the Burt Rape Myth Acceptance Scale. Less than one-half of the 68 articles examined reported reliability coefficients for the data collected. Almost one-third of the studies did not mention reliability. Examples of acceptable reliability reporting are provided. It is argued that reliability coefficients for the data actually analyzed should always be assessed and reported when interpreting program results. Implicationsfor school health research and practice are discussed. PMID:15929595

  10. Steam generator group project: Task 13 final report: Nondestructive examination validation

    SciTech Connect

    Bradley, E.R.; Doctor, P.G.; Ferris, R.H.; Buchanan, J.A.

    1988-08-01

    The Steam Generator Group Project (SGGP) was a multi-task effort using the retired-from-service Surry 2A pressurized water reactor steam generator as a test bed to investigate the reliability and effectiveness of in-service nondestructive eddy current (EC) inspection equipment and procedures. The information developed provided the technical basis for recommendations for improved in- service inspection and tube plugging criteria of steam generators. This report describes the results and analysis from Task 13--NDE Validation. The primary objective of Task 13 was to validate the EC inspection to detect and size tube defects. Additional objectives were to assess the nature and severity of tube degradation from all regions of the generator and to measure the remaining integrity of degraded specimens by burst testing. More than 550 specimens were removed from the generator and included in the validation studies. The bases for selecting the specimens and the methods and procedures used for specimen removal from the generator are reported. Results from metallurgical examinations of these specimens are presented and discussed. These examinations include visual inspection of all specimens to locate and identify tube degradation, metallographic examination of selected specimens to establish defect severity and burst testing of selected specimens to establish the remaining integrity of service-degraded tubes. Statistical analysis of the combined metallurgical and EC data to determine the probability of detection (POD) and sizing accuracy are reported along with a discussion of the factors which influenced the EC results. Finally, listings of the metallurgical and corresponding EC data bases are given. 12 refs., 141 figs., 24 tabs.

  11. Reliability model generator specification

    NASA Technical Reports Server (NTRS)

    Cohen, Gerald C.; Mccann, Catherine

    1990-01-01

    The Reliability Model Generator (RMG), a program which produces reliability models from block diagrams for ASSIST, the interface for the reliability evaluation tool SURE is described. An account is given of motivation for RMG and the implemented algorithms are discussed. The appendices contain the algorithms and two detailed traces of examples.

  12. Modelling based radiography for NDE of subsea pipelines

    NASA Astrophysics Data System (ADS)

    Haith, Misty I.; Ewert, Uwe; Hohendorf, Stefan; Bellon, Carsten; Deresch, Andreas; Huthwaite, Peter; Lowe, Michael J. S.; Zscherpel, Uwe

    2016-02-01

    This work presents the use of limited experimental measurements to develop a set of calibrated simulation parameters that can then be used for reliable simulation of subsea pipeline inspections. The modelling software aRTist is used as the simulation tool, and the calibration is through comparison with experimental images of a well characterised sample in a water tank. Image quality parameters such as signal-to-noise ratio, contrast and basic spatial resolution are compared with the aim of matching simulated values to experimental results. Currently the model is partially calibrated, with signal-to-noise ratio successfully matched while differences are still found in contrast-to-noise ratio comparisons. This means that measurements depending on absolute intensity are not accurate enough in the simulation at this stage. However, the simulation is found to be accurate for wall thickness measurements in tangential images, which are not based on absolute intensity, with simulated and experimental cases producing similar results.

  13. Electronics reliability and measurement technology

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S. (Editor)

    1987-01-01

    A summary is presented of the Electronics Reliability and Measurement Technology Workshop. The meeting examined the U.S. electronics industry with particular focus on reliability and state-of-the-art technology. A general consensus of the approximately 75 attendees was that "the U.S. electronics industries are facing a crisis that may threaten their existence". The workshop had specific objectives to discuss mechanisms to improve areas such as reliability, yield, and performance while reducing failure rates, delivery times, and cost. The findings of the workshop addressed various aspects of the industry from wafers to parts to assemblies. Key problem areas that were singled out for attention are identified, and action items necessary to accomplish their resolution are recommended.

  14. Assessment of NDE Methods on Inspection of HDPE Butt Fusion Piping Joints for Lack of Fusion with Validation from Mechanical Testing

    SciTech Connect

    Anderson, Michael T.; Cinson, Anthony D.; Crawford, Susan L.; Doctor, Steven R.; Moran, Traci L.; Watts, Michael W.

    2010-12-01

    Studies at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, are being conducted to evaluate nondestructive examinations (NDE) coupled with mechanical testing of butt fusion joints in high-density polyethylene (HDPE) pipe for assessing lack of fusion. The work provides information to the U.S. Nuclear Regulatory Commission (NRC) on the effectiveness of volumetric inspection techniques of HDPE butt fusion joints in Section III, Division 1, Class 3, buried piping systems in nuclear power plants. This paper describes results from preliminary assessments using ultrasonic and microwave nondestructive techniques and mechanical testing with the high-speed tensile impact test and the side-bend test for determining joint integrity. A series of butt joints were fabricated in 3408, 12-in. IPS DR-11 HDPE material by varying the fusion parameters to create good joints and joints containing a range of lack-of-fusion conditions. Six of these butt joints were volumetrically examined with time-of-flight diffraction (TOFD), phased-array (PA) ultrasound, and the Evisive microwave system. The outer-diameter weld beads were removed for the microwave inspection. In two of the four pipes, both the outer and inner weld beads were removed and the pipe joints re-evaluated. The pipes were sectioned and the joints destructively evaluated with the side-bend test by cutting portions of the fusion joint into slices that were planed and bent. The last step in this limited study will be to correlate the fusion parameters, nondestructive, and destructive evaluation results to validate the effectiveness of what each NDE technology detects and what each does not detect. The results of the correlation will be used in identifying any future work that is needed.

  15. NDE measurements for understanding of performance: A few case studies on engineering components, human health and cultural heritage

    NASA Astrophysics Data System (ADS)

    Raj, Baldev; Venkatraman, B.

    2013-01-01

    Life cycle management involves a seamless integration of materials, design, analysis, production, manufacturing, and degradation plus, a wide variety of disciplines relating to surveillance and characterisation with adequate feedback and control. Science and technology of non-destructive evaluation (NDE) links all these domains and disciplines together in a seamless and robust manner. A number of research programs on NDE science and technology have evolved during the last four decades world over including the one at Indira Gandhi Centre for Atomic Research, Kalpakkam, initiated and nurtured by the first author. Many engineering and technology challenges pertaining to fast spectrum reactors have been successfully solved by this Centre through development of innovative sensors, procedures and coupled with strong basic science and modeling approaches. These technologies have also been selectively applied in gaining insights of human health and cultural heritage. This paper highlights some of the innovative NDE sensors and techniques developed in the field of electromagnetic NDE and their successful applications. A few interesting case studies pertaining to NDE in heritage and healthcare using acoustic and thermal methods are also presented.

  16. Stability Reliability of the Behavior Rating Profile.

    ERIC Educational Resources Information Center

    Ellers, Robert A.; And Others

    1989-01-01

    Examined test-retest stability of Behavior Rating Profile for students grades l-12 (N=198), parents (N=212), and teachers (N=176) on 3 norm-referenced scales. Found Teacher Rating scale reliable across all grades for screening and eligibility, Parent Rating scale reliable for Grade 3-12 screening and Grade 3-6,ll, and l2, eligibility. Found…

  17. Reliability Generalization of the Psychopathy Checklist Applied in Youthful Samples

    ERIC Educational Resources Information Center

    Campbell, Justin S.; Pulos, Steven; Hogan, Mike; Murry, Francie

    2005-01-01

    This study examines the average reliability of Hare Psychopathy Checklists (PCLs) adapted for use in samples of youthful offenders (aged 12 to 21 years). Two forms of reliability are examined: 18 alpha estimates of internal consistency and 18 intraclass correlation (two or more raters) estimates of interrater reliability. The results, an average…

  18. Comparison of NDE techniques for sintered-SiC components

    NASA Technical Reports Server (NTRS)

    Srinivasan, M.; Lawler, D.; Inglehart, L. J.; Thomas, R. L.; Yuhas, D.

    1982-01-01

    High frequency, bulk-wave ultrasonics detected defects in manufactured SiC components. In addition, gas-turbine blades and vanes were examined by scanning laser acoustic microscopy (SLAM). Comparative results obtained on simple shapes such as disks and bars by microfocus X-ray radiography, ultrasonics, scanning photoacoustic spectroscopy, and SLAM are discussed.

  19. Instrumentation, Monitoring and NDE for New Fast Reactors

    SciTech Connect

    Bond, Leonard J.; Doctor, Steven R.; Bunch, Kyle J.; Good, Morris S.; Waltar, Alan E.

    2007-07-28

    The Global Nuclear Energy Partnership (GNEP) has been proposed as a viable system in which to close the fuel cycle in a manner consistent with markedly expanding the global role of nuclear power while significantly reducing proliferation risks. A key part of this system relies on the development of actinide transmutation, which can only be effectively accomplished in a fast-spectrum reactor. The fundamental physics for fast reactors is well established. However, to achieve higher standards of safety and reliability, operate with longer intervals between outages, and achieve high operating capacity factors, new instrumentation and on-line monitoring capabilities will be required--during both fabrication and operation. Since the Fast Flux Test Facility (FFTF) and Experimental Breeder Reactor – II (EBR-II) reactors were operational in the USA, there have been major advances in instrumentation, not the least being the move to digital systems. Some specific capabilities have been developed outside the USA, but new or at least re-established capabilities will be required. In many cases the only available information is in reports and papers. New and improved sensors and instrumentation will be required. Advanced instrumentation has been developed for high-temperature/high-flux conditions in some cases, but most of the original researchers and manufacturers are retired or no longer in business.

  20. Development of distribution system reliability and risk analysis models

    NASA Astrophysics Data System (ADS)

    Northcote-Green, J. E. D.; Vismor, T. D.; Brooks, C. L.

    1981-08-01

    The overall objectives of a research project were to: determine distribution reliability assessment methods currently used by the industry; develop a general outage reporting scheme suitable for a wide variety of distributing utilities (reliability model); develop a model for predicting the reliability of future system configurations (risk model); and compile a handbook of reliability assessment methods designed specifically for use by the practicing distribution engineer. Emphasis was placed on compiling and organizing reliability assessment techniques presently used by the industry. The project examined reliability evaluation from two perspectives: historical and predictive assessment. Two reliability assessment models, HISRAM - the historical reliability assessment model and PRAM - the predictive reliability assessment model were developed. Each model was tested in a utility environment by the Duquesne Light Company and the Public Service Electric and Gas Company of New Jersey. A survey of 56 diverse utilities served as a basis for examining current distribution reliability assessment practices in the electric power industry.

  1. METHODOLOGY FOR EXAMINING SYSTEM AGING DUE TO INTERACTIONS BETWEEN CHEMICALLY INCOMPATIBLE MATERIALS

    SciTech Connect

    J. DENINGER; J. TANSKI

    1999-04-01

    We start with a stored and unused population of fielded engineered units that are composed of chemically incompatible materials. The units age primarily through heterogeneous chemical reactions between the materials resulting in possible degradation in performance. The engineered units are unused in storage, but may be called into actual service at any time. We sample several units from the population per year and perform a number of non-destructive evaluation (NDE) techniques, such as radiography, low-frequency vibration analysis, and ultrasonic imaging on the selected units. From those units, some are selected for destructive testing (D-test) involving disassembly and testing of internal parts and components. Chemical analyses, mechanical properties measurements and other tests are performed. All of the above steps provide information that is used in the system simulation mathematical model. The system simulation model incorporates chemical reactions and gas-solid transport processes, along with changes in both the surface and bulk properties of the solids. Model results are used to suggest improvements in NDE analyses of the units and improvements in component and material analyses. Model results give trending indications of individual component and overall system changes over time, plus some understanding of the mechanisms involved which allow science-based predictions of the aged state of the units in future times. The NDE, D-test, and model results can also be used to assess statistically the reliability and performance of the overall aging population of units.

  2. Examining the Reliability of Student Growth Percentiles Using Multidimensional IRT

    ERIC Educational Resources Information Center

    Monroe, Scott; Cai, Li

    2015-01-01

    Student growth percentiles (SGPs, Betebenner, 2009) are used to locate a student's current score in a conditional distribution based on the student's past scores. Currently, following Betebenner (2009), quantile regression (QR) is most often used operationally to estimate the SGPs. Alternatively, multidimensional item response theory (MIRT) may…

  3. Ear examination

    MedlinePlus

    King EF, Couch ME. History, physical examination, and the preoperative evaluation. In: Flint PW, Haughey BH, Lund LJ, et al, eds. Cummings Otolaryngology: Head & Neck Surgery . 6th ed. Philadelphia, ...

  4. [Examination procedures].

    PubMed

    Vassault, A; Arnaud, J; Szymanovicz, A

    2010-12-01

    Examination procedures have to be written for each examination according to the standard requirements. Using CE marked devices, technical inserts can be used, but because of their lack of homogeneity, it could be easier to document their use as a standard procedure. Document control policy applies for those procedures, the content of which could be as provided in this document. Electronic manuals can be used as well. PMID:21613016

  5. Application of automated NDE data evaluation to missile and aircraft systems

    NASA Astrophysics Data System (ADS)

    Hildreth, Joseph H.

    1996-11-01

    As part of the advanced launch system technology development effort begun in 1989, the Air Force initiated a program to automate to the extent possible the processing NDE data from the inspection of solid rocket motors during fabrication. The computerized system, called the automated NDE data evaluation system (ANDES), was developed under contract to Martin Marietta. The generic ANDES system has been tailored to support inspection tasks at two Air Logistic Centers in the Air Force. These centers are the Ogden Air Logistic Center at Hill AFB, UT and the San Antonio Air Logistic Center at Kelly AFB, TX. The ANDES systems can be configured to process digital or digitize NDE data from any source. The system will analyze the data for anomalies, classify detected anomalies, and make a recommendation ont he serviceability of the component containing the anomalies base on established criteria. The ANDES systems at Hill AFB is configured to process x-ray computed tomography (CT) images in support of the surveillance activities on the Minuteman III third stage solid rocket motors. The system functions as a supplement to the visual image analysis effort and as an automated report generation and electronic report storage device. The ANDES system installed at Kelly AFB also processes CT images. The components supported are the oil scavenging assembly from the F-100 aircraft engine,t he yoke pivot block casting data images for void content and cracks and a braised joint on the oil scavenge tube for leak paths and total wetted area. The paper will briefly discuss the ANDES development history, the system hardware and software architectures employed at both Hill AFB and Kelly AFB, and a brief description of the performance of the operational systems.

  6. NDE Development for Inspection of the Ares I Crew Launch Vehicle

    NASA Technical Reports Server (NTRS)

    Richter, Joel; Russell, Sam S.

    2007-01-01

    NASA is designing a new crewed launch vehicle called Ares I to replace the Space Shuttle after its scheduled retirement in 2010. This new launch vehicle will build on the Shuttle technology in many ways including using a first stage based upon the Space Shuttle Solid Rocket Booster, advanced aluminum alloys for the second stage tanks, and friction stir welding to assemble the second stage. Friction stir welding uses a spinning pin that is inserted in the joint between two panels that are to be welded. The pin mechanically mixes the metal together below the melting temperature to form the weld. Friction stir welding allows high strength joints in metals that would otherwise lose much of their strength as they are melted during the fusion welding process. One significant change from the Space Shuttle that impacts NDE is the implementation of self-reacting friction stir welding for non-linear welds on the primary metallic structure. The self-reacting technique differs from the conventional technique because the load of the pin tool pressing down on the metal being joined is reacted by a nut on the end of the tool rather than an anvil behind the part. No spacecraft has ever flown with a self-reacting friction stir weld, so this is a major advancement in the manufacturing process, bringing with it a whole new set of challenges for NDE to overcome. Another impact is the proposed usage of an aluminum face sheet, phenolic honeycomb sandwich structure for a common bulkhead between the fuel and oxidizer tanks. This design was used on the second stage of Saturn IB and the second and third stages of Saturn V, but both the manufacturing and subsequent inspection were very costly and time consuming so a more efficient inspection method is sought. The current state of development of these inspections will be presented, along with other information pertinent to NDE of the Ares I.

  7. Human reliability analysis

    SciTech Connect

    Dougherty, E.M.; Fragola, J.R.

    1988-01-01

    The authors present a treatment of human reliability analysis incorporating an introduction to probabilistic risk assessment for nuclear power generating stations. They treat the subject according to the framework established for general systems theory. Draws upon reliability analysis, psychology, human factors engineering, and statistics, integrating elements of these fields within a systems framework. Provides a history of human reliability analysis, and includes examples of the application of the systems approach.

  8. Software reliability experiments data analysis and investigation

    NASA Technical Reports Server (NTRS)

    Walker, J. Leslie; Caglayan, Alper K.

    1991-01-01

    The objectives are to investigate the fundamental reasons which cause independently developed software programs to fail dependently, and to examine fault tolerant software structures which maximize reliability gain in the presence of such dependent failure behavior. The authors used 20 redundant programs from a software reliability experiment to analyze the software errors causing coincident failures, to compare the reliability of N-version and recovery block structures composed of these programs, and to examine the impact of diversity on software reliability using subpopulations of these programs. The results indicate that both conceptually related and unrelated errors can cause coincident failures and that recovery block structures offer more reliability gain than N-version structures if acceptance checks that fail independently from the software components are available. The authors present a theory of general program checkers that have potential application for acceptance tests.

  9. Decomposition in reliability analysis of fault-tolerant systems

    NASA Technical Reports Server (NTRS)

    Trivedi, K. S.; Geist, R. M.

    1983-01-01

    The existing approaches to reliability modeling are briefly reviewed. An examination of the limitations of the existing approaches in modeling ultrareliable fault-tolerant systems illustrates the need to use decomposition techniques. The notion of behavioral decomposition is introduced for dealing with reliability models with a large number of states, and a series of examples is presented. The CARE (computer-aided reliability estimation) and HARP (hybrid automated reliability predictor) approaches to reliability are discussed.

  10. Software Reliability 2002

    NASA Technical Reports Server (NTRS)

    Wallace, Dolores R.

    2003-01-01

    In FY01 we learned that hardware reliability models need substantial changes to account for differences in software, thus making software reliability measurements more effective, accurate, and easier to apply. These reliability models are generally based on familiar distributions or parametric methods. An obvious question is 'What new statistical and probability models can be developed using non-parametric and distribution-free methods instead of the traditional parametric method?" Two approaches to software reliability engineering appear somewhat promising. The first study, begin in FY01, is based in hardware reliability, a very well established science that has many aspects that can be applied to software. This research effort has investigated mathematical aspects of hardware reliability and has identified those applicable to software. Currently the research effort is applying and testing these approaches to software reliability measurement, These parametric models require much project data that may be difficult to apply and interpret. Projects at GSFC are often complex in both technology and schedules. Assessing and estimating reliability of the final system is extremely difficult when various subsystems are tested and completed long before others. Parametric and distribution free techniques may offer a new and accurate way of modeling failure time and other project data to provide earlier and more accurate estimates of system reliability.

  11. Reliability of fluid systems

    NASA Astrophysics Data System (ADS)

    Kopáček, Jaroslav; Fojtášek, Kamil; Dvořák, Lukáš

    2016-03-01

    This paper focuses on the importance of detection reliability, especially in complex fluid systems for demanding production technology. The initial criterion for assessing the reliability is the failure of object (element), which is seen as a random variable and their data (values) can be processed using by the mathematical methods of theory probability and statistics. They are defined the basic indicators of reliability and their applications in calculations of serial, parallel and backed-up systems. For illustration, there are calculation examples of indicators of reliability for various elements of the system and for the selected pneumatic circuit.

  12. Independent Assessment of Instrumentation for ISS On-Orbit NDE. Volume 2; Appendices

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I.

    2013-01-01

    International Space Station (ISS) Structural and Mechanical Systems Manager, requested that the NASA Engineering and Safety Center (NESC) provide a quantitative assessment of commercially available nondestructive evaluation (NDE) instruments for potential application to the ISS. This work supports risk mitigation as outlined in the ISS Integrated Risk Management Application (IRMA) Watch Item #4669, which addresses the requirement for structural integrity after an ISS pressure wall leak in the event of a penetration due to micrometeoroid or debris (MMOD) impact. This document contains the appendices the final report.

  13. Independent Assessment of Instrumentation for ISS On-Orbit NDE. Volume 1

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I

    2013-01-01

    International Space Station (ISS) Structural and Mechanical Systems Manager, requested that the NASA Engineering and Safety Center (NESC) provide a quantitative assessment of commercially available nondestructive evaluation (NDE) instruments for potential application to the ISS. This work supports risk mitigation as outlined in the ISS Integrated Risk Management Application (IRMA) Watch Item #4669, which addresses the requirement for structural integrity after an ISS pressure wall leak in the event of a penetration due to micrometeoroid or debris (MMOD) impact. This document contains the outcome of the NESC assessment.

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

    SciTech Connect

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

    2005-12-01

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

  15. TANK INSPECTION NDE RESULTS FOR FISCAL YEAR 2007INCLUDING WASTE TANKS 35, 36, 37, 38 AND 15

    SciTech Connect

    Elder, J

    2007-09-27

    Ultrasonic (UT) nondestructive examinations (NDE) were performed on waste storage tanks 35, 36, 37, 38 and 15 at the Savannah River Site as a part of the 'In-Service Inspection (ISI) Program for High Level Waste Tanks.' 1 The inspections were performed from the annular space of the waste storage tanks. The inspections included thickness mapping and crack detection scans on specified areas of the tanks covering all present and historic interface levels and selected welds with particular emphasis on the vapor space regions. Including the tanks in this report, all of the 27 Type III tanks at SRS have been inspected in accordance with the ISI plan. Of the four Type III tanks examined this year, all had areas of reportable thickness in either the Primary or Secondary tank. All of these areas on the primary tank are attributed to fabrication artifacts. None of the four Type III tanks examined this year showed evidence of service induced thinning on the primary wall. All four tanks had secondary wall and/or floor plates where the remaining thickness measured below the 10% wall loss criteria. Tank 15, a Type II, non-stress relieved, waste tank was also inspected this fiscal year as part of the ISI program. The same examination techniques were used on Tank 15 as on the Type III tanks. Tank 15 has been out of service due to leakage from stress corrosion cracking (SCC). Inspections were performed to validate known corrosion models and determine if crack growth occurred since the previous examination five years ago. Several cracks were found to have increased in length perpendicular to the weld seam. In the areas of the 27 Type III tanks inspected to date, ten tanks have reportable thickness in the primary wall and 17 have reportable thickness in the secondary tank walls or floor. All of the reportable thickness areas in the primary walls are from fabrication artifacts. Incipient pitting has been detected in five of the 27 Type III primary tanks. No cracking was detected in

  16. Characterization of sintered SiC by using NDE

    NASA Technical Reports Server (NTRS)

    Baaklini, George Y.

    1988-01-01

    Capabilities of projection microfocus X-radiography and of ultrasonic velocity and attenuation for characterizing silicon carbide specimens were assessed. Silicon carbide batches covered a range of densities and different microstructural characteristics. Room-temperature, four-point flexural strength tests were conducted. Fractography was used to identify types, sizes, and locations of fracture origins. Fracture toughness values were calculated from fracture strength and flaw characterization data. Detection capabilities of radiography for fracture-causing flaws were evaluated. Applicability of ultrasonics for verifying material strength and toughness was examined. Radiography proved useful in detecting high-density inclusions and isolated voids, but failed in detecting surface and subsurface agglomerates and large grains as fracture origins. Ultrasonic velocity dependency on density was evident. Attenuation dependency on density and mean pore size was clearly demonstrated. Understanding attenuation as a function of toughness was limited by shortcomings in K sub IC determination.

  17. Photovoltaic performance and reliability workshop

    SciTech Connect

    Kroposki, B

    1996-10-01

    This proceedings is the compilation of papers presented at the ninth PV Performance and Reliability Workshop held at the Sheraton Denver West Hotel on September 4--6, 1996. This years workshop included presentations from 25 speakers and had over 100 attendees. All of the presentations that were given are included in this proceedings. Topics of the papers included: defining service lifetime and developing models for PV module lifetime; examining and determining failure and degradation mechanisms in PV modules; combining IEEE/IEC/UL testing procedures; AC module performance and reliability testing; inverter reliability/qualification testing; standardization of utility interconnect requirements for PV systems; need activities to separate variables by testing individual components of PV systems (e.g. cells, modules, batteries, inverters,charge controllers) for individual reliability and then test them in actual system configurations; more results reported from field experience on modules, inverters, batteries, and charge controllers from field deployed PV systems; and system certification and standardized testing for stand-alone and grid-tied systems.

  18. Hawaii electric system reliability.

    SciTech Connect

    Silva Monroy, Cesar Augusto; Loose, Verne William

    2012-09-01

    This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers' views of reliability %E2%80%9Cworth%E2%80%9D and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers' views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.

  19. Reliability Analysis and Reliability-Based Design Optimization of Circular Composite Cylinders Under Axial Compression

    NASA Technical Reports Server (NTRS)

    Rais-Rohani, Masoud

    2001-01-01

    This report describes the preliminary results of an investigation on component reliability analysis and reliability-based design optimization of thin-walled circular composite cylinders with average diameter and average length of 15 inches. Structural reliability is based on axial buckling strength of the cylinder. Both Monte Carlo simulation and First Order Reliability Method are considered for reliability analysis with the latter incorporated into the reliability-based structural optimization problem. To improve the efficiency of reliability sensitivity analysis and design optimization solution, the buckling strength of the cylinder is estimated using a second-order response surface model. The sensitivity of the reliability index with respect to the mean and standard deviation of each random variable is calculated and compared. The reliability index is found to be extremely sensitive to the applied load and elastic modulus of the material in the fiber direction. The cylinder diameter was found to have the third highest impact on the reliability index. Also the uncertainty in the applied load, captured by examining different values for its coefficient of variation, is found to have a large influence on cylinder reliability. The optimization problem for minimum weight is solved subject to a design constraint on element reliability index. The methodology, solution procedure and optimization results are included in this report.

  20. Investigation of Fiber Waviness in a Thick Glass Composite Beam Using THz NDE

    NASA Technical Reports Server (NTRS)

    Anastasi, Robert F.

    2008-01-01

    Fiber waviness in laminated composite material is introduced during manufacture because of uneven curing, resin shrinkage, or ply buckling caused by bending the composite lay-up into its final shape prior to curing. The resulting waviness has a detrimental effect on mechanical properties, therefore this condition is important to detect and characterize. Ultrasonic characterization methods are difficult to interpret because elastic wave propagation is highly dependent on ply orientation and material stresses. By comparison, the pulsed terahertz response of the composite is shown to provide clear indications of the fiber waviness. Pulsed Terahertz NDE is an electromagnetic inspection method that operates in the frequency range between 300 GHz and 3 THz. Its propagation is influenced by refractive index variations and interfaces. This work applies pulsed Terahertz NDE to the inspection of a thick composite beam with fiber waviness. The sample is a laminated glass composite material approximately 15mm thick with a 90-degree bend. Terahertz response from the planar section, away from the bend, is indicative of a homogeneous material with no major reflections from internal plies, while the multiple reflections at the bend area correspond to the fiber waviness. Results of these measurements are presented for the planar and bend areas.

  1. Directed Design of Experiments for Validating Probability of Detection Capability of NDE Systems (DOEPOD)

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    2015-01-01

    Directed Design of Experiments for Validating Probability of Detection Capability of NDE Systems (DOEPOD) Manual v.1.2 The capability of an inspection system is established by applications of various methodologies to determine the probability of detection (POD). One accepted metric of an adequate inspection system is that there is 95% confidence that the POD is greater than 90% (90/95 POD). Design of experiments for validating probability of detection capability of nondestructive evaluation (NDE) systems (DOEPOD) is a methodology that is implemented via software to serve as a diagnostic tool providing detailed analysis of POD test data, guidance on establishing data distribution requirements, and resolving test issues. DOEPOD demands utilization of observance of occurrences. The DOEPOD capability has been developed to provide an efficient and accurate methodology that yields observed POD and confidence bounds for both Hit-Miss or signal amplitude testing. DOEPOD does not assume prescribed POD logarithmic or similar functions with assumed adequacy over a wide range of flaw sizes and inspection system technologies, so that multi-parameter curve fitting or model optimization approaches to generate a POD curve are not required. DOEPOD applications for supporting inspector qualifications is included.

  2. Digital Audio Signal Processing and Nde: AN Unlikely but Valuable Partnership

    NASA Astrophysics Data System (ADS)

    Gaydecki, Patrick

    2008-02-01

    In the Digital Signal Processing (DSP) group, within the School of Electrical and Electronic Engineering at The University of Manchester, research is conducted into two seemingly distinct and disparate subjects: instrumentation for nondestructive evaluation, and DSP systems & algorithms for digital audio. We have often found that many of the hardware systems and algorithms employed to recover, extract or enhance audio signals may also be applied to signals provided by ultrasonic or magnetic NDE instruments. Furthermore, modern DSP hardware is so fast (typically performing hundreds of millions of operations per second), that much of the processing and signal reconstruction may be performed in real time. Here, we describe some of the hardware systems we have developed, together with algorithms that can be implemented both in real time and offline. A next generation system has now been designed, which incorporates a processor operating at 0.55 Giga MMACS, six input and eight output analogue channels, digital input/output in the form of S/PDIF, a JTAG and a USB interface. The software allows the user, with no knowledge of filter theory or programming, to design and run standard or arbitrary FIR, IIR and adaptive filters. Using audio as a vehicle, we can demonstrate the remarkable properties of modern reconstruction algorithms when used in conjunction with such hardware; applications in NDE include signal enhancement and recovery in acoustic, ultrasonic, magnetic and eddy current modalities.

  3. Exploration of COTS Ultrasonic NDE Methods for ISS MMOD Impact Analysis

    NASA Technical Reports Server (NTRS)

    Violette, Daniel P.; Koshti, Ajay; Stanley, David

    2012-01-01

    The high orbital speed of the International Space Station (ISS) has created a concern about Micro-Meteorite and Orbital Debris (MMOD). The possibility exists that such an impact could cause significant damage to the ISS pressure wall, and possibly lead to a pressure leak. This paper explores the potential of using commercial off-the-shelf (COTS) Ultrasonic Non-Destructive Evaluation (NDE) techniques in order to inspect and analyze MMOD impact damage if such an event would happen to occur. Different types of intra vehicular activity (IVA) Ultrasonic NDE equipment were evaluated, including the Olympus Omniscan MX and the General Electric Phasor XS. The equipment was tested by inspecting various aluminum standards and impact damage test plates in order to determine technological limitations of the equipment as well as the ease of use and availability of features. This study allowed for the design of scanning procedures in order to evaluate the extent of damage caused by an MMOD impact. Lastly, comparisons were drawn between the different pieces of COTS software and a recommendation is made based on each device s capability.

  4. A Software Platform for Post-Processing Waveform-Based NDE

    NASA Technical Reports Server (NTRS)

    Roth, Donald J.; Martin, Richard E.; Seebo, Jeff P.; Trinh, Long B.; Walker, James L.; Winfree, William P.

    2007-01-01

    Ultrasonic, microwave, and terahertz nondestructive evaluation imaging systems generally require the acquisition of waveforms at each scan point to form an image. For such systems, signal and image processing methods are commonly needed to extract information from the waves and improve resolution of, and highlight, defects in the image. Since some similarity exists for all waveform-based NDE methods, it would seem a common software platform containing multiple signal and image processing techniques to process the waveforms and images makes sense where multiple techniques, scientists, engineers, and organizations are involved. This presentation describes NASA Glenn Research Center's approach in developing a common software platform for processing waveform-based NDE signals and images. This platform is currently in use at NASA Glenn and at Lockheed Martin Michoud Assembly Facility for processing of pulsed terahertz and ultrasonic data. Highlights of the software operation will be given. A case study will be shown for use with terahertz data. The authors also request scientists and engineers who are interested in sharing customized signal and image processing algorithms to contribute to this effort by letting the authors code up and include these algorithms in future releases.

  5. Robotic Inspection System for Non-Destructive Evaluation (nde) of Pipes

    NASA Astrophysics Data System (ADS)

    Mackenzie, L. D.; Pierce, S. G.; Hayward, G.

    2009-03-01

    The demand for remote inspection of pipework in the processing cells of nuclear plant provides significant challenges of access, navigation, inspection technique and data communication. Such processing cells typically contain several kilometres of densely packed pipework whose actual physical layout may be poorly documented. Access to these pipes is typically afforded through the radiation shield via a small removable concrete plug which may be several meters from the actual inspection site, thus considerably complicating practical inspection. The current research focuses on the robotic deployment of multiple NDE payloads for weld inspection along non-ferritic steel pipework (thus precluding use of magnetic traction options). A fully wireless robotic inspection platform has been developed that is capable of travelling along the outside of a pipe at any orientation, while avoiding obstacles such as pipe hangers and delivering a variety of NDE payloads. An eddy current array system provides rapid imaging capabilities for surface breaking defects while an on-board camera, in addition to assisting with navigation tasks, also allows real time image processing to identify potential defects. All sensor data can be processed by the embedded microcontroller or transmitted wirelessly back to the point of access for post-processing analysis.

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

    PubMed

    Li, Minghui; Hayward, Gordon

    2012-01-01

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

  7. Composite Materials NDE Using Enhanced Leaky Lamb Wave Dispersion Data Acquisition Method

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Mal, Ajit; Lih, Shyh-Shiuh; Chang, Zensheu

    1999-01-01

    The leaky Lamb wave (LLW) technique is approaching a maturity level that is making it an attractive quantitative NDE tool for composites and bonded joints. Since it was first observed in 1982, the phenomenon has been studied extensively, particularly in composite materials. The wave is induced by oblique insonification using a pitch-catch arrangement and the plate wave modes are detected by identifying minima in the reflected spectra to obtain the dispersion data. The wave behavior in multi-orientation laminates has been well documented and corroborated experimentally with high accuracy. The sensitivity of the wave to the elastic constants of the material and to the boundary conditions led to the capability to measure the elastic properties of bonded joints. Recently, the authors significantly enhanced the LLW method's capability by increasing the speed of the data acquisition, the number of modes that can be identified and the accuracy of the data inversion. In spite of the theoretical and experimental progress, methods that employ oblique insonification of composites are still not being applied as standard industrial NDE methods. The authors investigated the issues that are hampering the transition of the LLW to industrial applications and identified 4 key issues. The current capability of the method and the nature of these issues are described in this paper.

  8. Remote Welding, NDE and Repair of DOE Standardized Canisters

    SciTech Connect

    Eric Larsen; Art Watkins; Timothy R. McJunkin; Dave Pace; Rodney Bitsoi

    2006-05-01

    The U.S. Department of Energy (DOE) created the National Spent Nuclear Fuel Program (NSNFP) to manage DOE’s spent nuclear fuel (SNF). One of the NSNFP’s tasks is to prepare spent nuclear fuel for storage, transportation, and disposal at the national repository. As part of this effort, the NSNFP developed a standardized canister for interim storage and transportation of SNF. These canisters will be built and sealed to American Society of Mechanical Engineers (ASME) Section III, Division 3 requirements. Packaging SNF usually is a three-step process: canister loading, closure welding, and closure weld verification. After loading SNF into the canisters, the canisters must be seal welded and the welds verified using a combination of visual, surface eddy current, and ultrasonic inspection or examination techniques. If unacceptable defects in the weld are detected, the defective sections of weld must be removed, re-welded, and re-inspected. Due to the high contamination and/or radiation fields involved with this process, all of these functions must be performed remotely in a hot cell. The prototype apparatus to perform these functions is a floor-mounted carousel that encircles the loaded canister; three stations perform the functions of welding, inspecting, and repairing the seal welds. A welding operator monitors and controls these functions remotely via a workstation located outside the hot cell. The discussion describes the hardware and software that have been developed and the results of testing that has been done to date.

  9. Waste Examination Assay Facility operations: TRU waste certification

    SciTech Connect

    Schultz, F.J.; Caylor, B.A.; Coffey, D.E.; Phoenix, L.B.

    1987-01-01

    The ORNL Waste Examination Assay Facility (WEAF) was established to nondestructively assay (NDA) transuranic (TRU) waste generated at Oak Ridge National Laboratory (ORNL). The present facility charter encompasses the NDA and nondestructive examination (NDE) of both TRU and low-level wastes (LLW). Presently, equipment includes a Neutron Assay System (NAS), a Segmented Gamma Scanner (SGS), a drum-sized Real-Time Radiography (RTR) system, and a Neutron Slab Detector (NSD). The first three instruments are computer interfaced. Approximately 2300 TRU waste drums have been assayed with the NAS and the SGS. Another 3000 TRU and LLW drums have been examined with the RTR unit. Computer data bases have been developed to collate the large amount of data generated during the assays and examinations. 6 refs., 1 tab.

  10. Photovoltaic system reliability

    SciTech Connect

    Maish, A.B.; Atcitty, C.; Greenberg, D.

    1997-10-01

    This paper discusses the reliability of several photovoltaic projects including SMUD`s PV Pioneer project, various projects monitored by Ascension Technology, and the Colorado Parks project. System times-to-failure range from 1 to 16 years, and maintenance costs range from 1 to 16 cents per kilowatt-hour. Factors contributing to the reliability of these systems are discussed, and practices are recommended that can be applied to future projects. This paper also discusses the methodology used to collect and analyze PV system reliability data.

  11. Optics-Only Calibration of a Neural-Net Based Optical NDE Method for Structural Health Monitoring

    NASA Technical Reports Server (NTRS)

    Decker, Arthur J.

    2004-01-01

    A calibration process is presented that uses optical measurements alone to calibrate a neural-net based NDE method. The method itself detects small changes in the vibration mode shapes of structures. The optics-only calibration process confirms previous work that the sensitivity to vibration-amplitude changes can be as small as 10 nanometers. A more practical value in an NDE service laboratory is shown to be 50 nanometers. Both model-generated and experimental calibrations are demonstrated using two implementations of the calibration technique. The implementations are based on previously published demonstrations of the NDE method and an alternative calibration procedure that depends on comparing neural-net and point sensor measurements. The optics-only calibration method, unlike the alternative method, does not require modifications of the structure being tested or the creation of calibration objects. The calibration process can be used to test improvements in the NDE process and to develop a vibration-mode-independence of damagedetection sensitivity. The calibration effort was intended to support NASA s objective to promote safety in the operations of ground test facilities or aviation safety, in general, by allowing the detection of the gradual onset of structural changes and damage.

  12. Development of a Remotely Operated NDE System for Inspection of Hanford's Double Shell Waste Tank Knuckle Regions

    SciTech Connect

    Pardini, Allan F.; Alzheimer, James M.; Crawford, Susan L.; Diaz, Aaron A.; Gervais, Kevin L.; Harris, Robert V.; Riechers, Douglas M.; Samuel, Todd J.; Schuster, George J.; Tucker, Joseph C.; Roberts, R. A.

    2001-09-28

    This report documents work performed at the PNNL in FY01 to support development of a Remotely Operated NDE (RONDE) system capable of inspecting the knuckle region of Hanford's DSTs. The development effort utilized commercial off-the-shelf (COTS) technology wherever possible and provided a transport and scanning device for implementing the SAFT and T-SAFT techniques.

  13. Relating design and environmental variables to reliability

    NASA Astrophysics Data System (ADS)

    Kolarik, William J.; Landers, Thomas L.

    The combination of space application and nuclear power source demands high reliability hardware. The possibilities of failure, either an inability to provide power or a catastrophic accident, must be minimized. Nuclear power experiences on the ground have led to highly sophisticated probabilistic risk assessment procedures, most of which require quantitative information to adequately assess such risks. In the area of hardware risk analysis, reliability information plays a key role. One of the lessons learned from the Three Mile Island experience is that thorough analyses of critical components are essential. Nuclear grade equipment shows some reliability advantages over commercial. However, no statistically significant difference has been found. A recent study pertaining to spacecraft electronics reliability, examined some 2500 malfunctions on more than 300 aircraft. The study classified the equipment failures into seven general categories. Design deficiencies and lack of environmental protection accounted for about half of all failures. Within each class, limited reliability modeling was performed using a Weibull failure model.

  14. Mobile visual examination and repackaging (MOVER) system

    SciTech Connect

    Los Alamos National Laboratory

    2001-01-01

    Process engineering and waste technology teams at LOS Alamos National Laboratory delivered a prototype Mobile Visual Examination and Repackaging (MOVER) system to the Waste Isolation Pilot Plant (WIPP) outside of Carlsbad, NM in October, 2000. This system was developed in response to compliance issues with legacy waste that was packaged in 55 gallons drums prior to release of WIPP's waste acceptance criteria (WAC). A statistical percentage of these 55 gallon drums will be opened and visually examined (VE) as part of re-characterization using Non-destructive examination (NDE) procedures. VE is an intrusive technique since the drum is opened, and as a result, there are more risks in spreading contamination. Hence, VE is performed in a glovebox to protect the workers and the environment. During VE, waste is pulled out of one drum, visually examined, the amount of plutonium measured if necessary, and the waste repackaged into one or more drums. MOVER can perform all these operations, along with having the capability to house the glovebox operations and all support equipment in a 40-foot-long container that can be transported to a site on a semi-trailer. This container is divided into three rooms, providing the level of safety and containment of a fixed facility. A key asset of mobile systems is the inherent need for modular design that reduces infrastructure costs and overhead. A mobile system like MOVER represents a technology base aimed at meeting DOE schedules to accelerate decommissioning of many sites.

  15. Software reliability studies

    NASA Technical Reports Server (NTRS)

    Wilson, Larry W.

    1989-01-01

    The longterm goal of this research is to identify or create a model for use in analyzing the reliability of flight control software. The immediate tasks addressed are the creation of data useful to the study of software reliability and production of results pertinent to software reliability through the analysis of existing reliability models and data. The completed data creation portion of this research consists of a Generic Checkout System (GCS) design document created in cooperation with NASA and Research Triangle Institute (RTI) experimenters. This will lead to design and code reviews with the resulting product being one of the versions used in the Terminal Descent Experiment being conducted by the Systems Validations Methods Branch (SVMB) of NASA/Langley. An appended paper details an investigation of the Jelinski-Moranda and Geometric models for software reliability. The models were given data from a process that they have correctly simulated and asked to make predictions about the reliability of that process. It was found that either model will usually fail to make good predictions. These problems were attributed to randomness in the data and replication of data was recommended.

  16. Advanced Instrumentation, Information, and Control System Technologies: Nondestructive Examination Technologies - FY11 Report

    SciTech Connect

    Meyer, Ryan M.; Coble, Jamie B.; Ramuhalli, Pradeep; Bond, Leonard J.

    2011-08-30

    Licensees of commercial nuclear power plants in the US are expected to submit license renewal applications for the period of operation of 60 to 80 years which has also been referred to as long term operation (LTO). The greatest challenges to LTO are associated with degradation of passive components as active components are routinely maintained and repaired or placed through maintenance programs. Some passive component degradation concerns include stress corrosion cracking (SCC) of metal components, radiation induced embrittlement of the reactor pressure vessel (RPV), degradation of buried piping, degradation of concrete containment structures, and degradation of cables. Proactive management of passive component aging employs three important elements including online monitoring of degradation, early detection of degradation at precursor stages, and application of prognostics for the prediction of remaining useful life (RUL). This document assesses several nondestructive examination (NDE) measurement technologies for integration into proactive aging management programs. The assessment is performed by discussing the three elements of proactive aging management identified above, considering the current state of the industry with respect to adopting these key elements, and analyzing measurement technologies for monitoring large cracks in metal components, monitoring early degradation at precursor stages, monitoring the degradation of concrete containment structures, and monitoring the degradation of cables. Specific and general needs have been identified through this assessment. General needs identified include the need for environmentally rugged sensors are needed that can operate reliably in an operating reactor environment, the need to identify parameters from precursor monitoring technologies that are unambiguously correlated with the level of pre-macro defect damage, and a methodology for identifying regions where precursor damage is most likely to initiate.

  17. Mission Reliability Estimation for Repairable Robot Teams

    NASA Technical Reports Server (NTRS)

    Trebi-Ollennu, Ashitey; Dolan, John; Stancliff, Stephen

    2010-01-01

    A mission reliability estimation method has been designed to translate mission requirements into choices of robot modules in order to configure a multi-robot team to have high reliability at minimal cost. In order to build cost-effective robot teams for long-term missions, one must be able to compare alternative design paradigms in a principled way by comparing the reliability of different robot models and robot team configurations. Core modules have been created including: a probabilistic module with reliability-cost characteristics, a method for combining the characteristics of multiple modules to determine an overall reliability-cost characteristic, and a method for the generation of legitimate module combinations based on mission specifications and the selection of the best of the resulting combinations from a cost-reliability standpoint. The developed methodology can be used to predict the probability of a mission being completed, given information about the components used to build the robots, as well as information about the mission tasks. In the research for this innovation, sample robot missions were examined and compared to the performance of robot teams with different numbers of robots and different numbers of spare components. Data that a mission designer would need was factored in, such as whether it would be better to have a spare robot versus an equivalent number of spare parts, or if mission cost can be reduced while maintaining reliability using spares. This analytical model was applied to an example robot mission, examining the cost-reliability tradeoffs among different team configurations. Particularly scrutinized were teams using either redundancy (spare robots) or repairability (spare components). Using conservative estimates of the cost-reliability relationship, results show that it is possible to significantly reduce the cost of a robotic mission by using cheaper, lower-reliability components and providing spares. This suggests that the

  18. Reliability and Accuracy of Surgical Resident Peer Ratings.

    ERIC Educational Resources Information Center

    Lutsky, Larry A.; And Others

    1993-01-01

    Reliability and accuracy of peer ratings by 32, 28, 33 general surgery residents over 3 years were examined. Peer ratings were found highly reliable, with high level of test-retest reliability replicated across three years. Halo effects appear to pose greatest threat to rater accuracy, though chief residents tended to exhibit less halo effect than…

  19. Uncertainties in obtaining high reliability from stress-strength models

    NASA Technical Reports Server (NTRS)

    Neal, Donald M.; Matthews, William T.; Vangel, Mark G.

    1992-01-01

    There has been a recent interest in determining high statistical reliability in risk assessment of aircraft components. The potential consequences are identified of incorrectly assuming a particular statistical distribution for stress or strength data used in obtaining the high reliability values. The computation of the reliability is defined as the probability of the strength being greater than the stress over the range of stress values. This method is often referred to as the stress-strength model. A sensitivity analysis was performed involving a comparison of reliability results in order to evaluate the effects of assuming specific statistical distributions. Both known population distributions, and those that differed slightly from the known, were considered. Results showed substantial differences in reliability estimates even for almost nondetectable differences in the assumed distributions. These differences represent a potential problem in using the stress-strength model for high reliability computations, since in practice it is impossible to ever know the exact (population) distribution. An alternative reliability computation procedure is examined involving determination of a lower bound on the reliability values using extreme value distributions. This procedure reduces the possibility of obtaining nonconservative reliability estimates. Results indicated the method can provide conservative bounds when computing high reliability. An alternative reliability computation procedure is examined involving determination of a lower bound on the reliability values using extreme value distributions. This procedure reduces the possibility of obtaining nonconservative reliability estimates. Results indicated the method can provide conservative bounds when computing high reliability.

  20. Statistical modelling of software reliability

    NASA Technical Reports Server (NTRS)

    Miller, Douglas R.

    1991-01-01

    During the six-month period from 1 April 1991 to 30 September 1991 the following research papers in statistical modeling of software reliability appeared: (1) A Nonparametric Software Reliability Growth Model; (2) On the Use and the Performance of Software Reliability Growth Models; (3) Research and Development Issues in Software Reliability Engineering; (4) Special Issues on Software; and (5) Software Reliability and Safety.

  1. Photovoltaic module reliability workshop

    NASA Astrophysics Data System (ADS)

    Mrig, L.

    The paper and presentations compiled in this volume form the Proceedings of the fourth in a series of Workshops sponsored by Solar Energy Research Institute (SERI/DOE) under the general theme of photovoltaic module reliability during the period 1986 to 1990. The reliability photovoltaic (PV) modules/systems is exceedingly important along with the initial cost and efficiency of modules if the PV technology has to make a major impact in the power generation market, and for it to compete with the conventional electricity producing technologies. The reliability of photovoltaic modules has progressed significantly in the last few years as evidenced by warrantees available on commercial modules of as long as 12 years. However, there is still need for substantial research and testing required to improve module field reliability to levels of 30 years or more. Several small groups of researchers are involved in this research, development, and monitoring activity around the world. In the U.S., PV manufacturers, DOE laboratories, electric utilities and others are engaged in the photovoltaic reliability research and testing. This group of researchers and others interested in this field were brought together under SERI/DOE sponsorship to exchange the technical knowledge and field experience as related to current information in this important field. The papers presented here reflect this effort.

  2. Proposed reliability cost model

    NASA Technical Reports Server (NTRS)

    Delionback, L. M.

    1973-01-01

    The research investigations which were involved in the study include: cost analysis/allocation, reliability and product assurance, forecasting methodology, systems analysis, and model-building. This is a classic example of an interdisciplinary problem, since the model-building requirements include the need for understanding and communication between technical disciplines on one hand, and the financial/accounting skill categories on the other. The systems approach is utilized within this context to establish a clearer and more objective relationship between reliability assurance and the subcategories (or subelements) that provide, or reenforce, the reliability assurance for a system. Subcategories are further subdivided as illustrated by a tree diagram. The reliability assurance elements can be seen to be potential alternative strategies, or approaches, depending on the specific goals/objectives of the trade studies. The scope was limited to the establishment of a proposed reliability cost-model format. The model format/approach is dependent upon the use of a series of subsystem-oriented CER's and sometimes possible CTR's, in devising a suitable cost-effective policy.

  3. Orbiter Autoland reliability analysis

    NASA Technical Reports Server (NTRS)

    Welch, D. Phillip

    1993-01-01

    The Space Shuttle Orbiter is the only space reentry vehicle in which the crew is seated upright. This position presents some physiological effects requiring countermeasures to prevent a crewmember from becoming incapacitated. This also introduces a potential need for automated vehicle landing capability. Autoland is a primary procedure that was identified as a requirement for landing following and extended duration orbiter mission. This report documents the results of the reliability analysis performed on the hardware required for an automated landing. A reliability block diagram was used to evaluate system reliability. The analysis considers the manual and automated landing modes currently available on the Orbiter. (Autoland is presently a backup system only.) Results of this study indicate a +/- 36 percent probability of successfully extending a nominal mission to 30 days. Enough variations were evaluated to verify that the reliability could be altered with missions planning and procedures. If the crew is modeled as being fully capable after 30 days, the probability of a successful manual landing is comparable to that of Autoland because much of the hardware is used for both manual and automated landing modes. The analysis indicates that the reliability for the manual mode is limited by the hardware and depends greatly on crew capability. Crew capability for a successful landing after 30 days has not been determined yet.

  4. Photovoltaic module reliability workshop

    SciTech Connect

    Mrig, L.

    1990-01-01

    The paper and presentations compiled in this volume form the Proceedings of the fourth in a series of Workshops sponsored by Solar Energy Research Institute (SERI/DOE) under the general theme of photovoltaic module reliability during the period 1986--1990. The reliability Photo Voltaic (PV) modules/systems is exceedingly important along with the initial cost and efficiency of modules if the PV technology has to make a major impact in the power generation market, and for it to compete with the conventional electricity producing technologies. The reliability of photovoltaic modules has progressed significantly in the last few years as evidenced by warranties available on commercial modules of as long as 12 years. However, there is still need for substantial research and testing required to improve module field reliability to levels of 30 years or more. Several small groups of researchers are involved in this research, development, and monitoring activity around the world. In the US, PV manufacturers, DOE laboratories, electric utilities and others are engaged in the photovoltaic reliability research and testing. This group of researchers and others interested in this field were brought together under SERI/DOE sponsorship to exchange the technical knowledge and field experience as related to current information in this important field. The papers presented here reflect this effort.

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

    SciTech Connect

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

    2012-09-01

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

  6. Evaluation of Waveform Mapping as a Signal Processing Tool for Quantitative Ultrasonic NDE

    NASA Technical Reports Server (NTRS)

    Johnston, Patrick H.; Kishoni, Doron

    1993-01-01

    The mapping of one pulsed waveform into another, more desirable waveform by the application of a time-domain filter has been employed in a number of NDE situations. The primary goal of these applications has been to improve the range resolution of an ultrasonic signal for detection of echoes arising from particular interfaces masked by the response of the transducer. The work presented here addresses the use of this technique for resolution enhancement in imaging situations and in mapping signals from different transducers to a common target waveform, allowing maintenance of quantitative calibration of ultrasonic systems. We also describe the use of this technique in terms of the frequency analysis of the resulting waveforms.

  7. Nde of Lumber and Natural Fiber Based Products with Air Coupled Ultrasound

    NASA Astrophysics Data System (ADS)

    Hsu, David K.; Utrata, David; Kuo, Monlin

    2010-02-01

    Due to the porous nature of wood and natural fiber based products, conventional fluid or gel coupled ultrasonic inspection is unsuitable. Air-coupled ultrasonic transmission scanning, being non-contact, is ideally suited for inspecting lumber, wood and natural fiber based products. We report here several successful applications of air-coupled ultrasound for the inspection of wood. Air-coupled ultrasonic scan at 120 kHz can easily detect "sinker-stock" lumber in which bacterial damage of ray tissue cells had occurred during anaerobic pond storage. Channels in ash lumber board caused by insect bore were imaged in transmission scan. Delamination and material inhomogeneities were mapped out in manufactured wood and natural fiber products including medium density fiberboards, compression molded shredded waste wood with formaldehyde resin, and acoustic panels molded with kenaf fibers. The study has demonstrated some of the capabilities of air-coupled ultrasound in the NDE of forest products.

  8. Object motion tracking in the NDE laboratory by random sample iterative closest point

    NASA Astrophysics Data System (ADS)

    Radkowski, Rafael; Wehr, David; Gregory, Elizabeth; Holland, Stephen D.

    2016-02-01

    We present a computationally efficient technique for real-time motion tracking in the NDE laboratory. Our goal is to track object shapes in an flash thermography test stand to determine the position and orientation of the specimen which facilitates to register thermography data to a 3D part model. Object shapes can be different specimens and fixtures. Specimens can be manually aligned at any test stand, the position and orientation of every a-priori known shape can be computed and forwarded to the data management software. Our technique relies on the random sample consensus (RANSAC) approach to the iterative closest point (ICP) problem for identifying object shapes, thus, it is robust in different situations. The paper introduces the computational techniques and experiments along with the results.

  9. US Air Force perspective on validated NDE - Past, present, and future

    NASA Astrophysics Data System (ADS)

    Lindgren, Eric A.

    2016-02-01

    The concept of inspection has accompanied aviation since the work of the Wright Brothers. Inspection for both initial quality/materials acceptance and readiness for flight have been coupled with US Air Force (USAF) since its inception as the US Army Signal Corps. Initial nondestructive evaluation work expanded beyond visual inspection to include radiography and magnetic particle in the 1920's and 1930's as air frames transitioned to metal and engines used higher strength steels. Within the USAF Research and Development community, a Nondestructive Test Section was stood up in 1952 and the Nondestructive Evaluation Branch (NDE) was established in 1974. In 2012 the name was changed to the Materials State Awareness Branch. This name change reflects the evolution from a primary focus on inspections for damage and defects in materials to the characterization of the underlying materials structure that governs properties of the materials of interest for Air Force applications.

  10. Impulse Response Estimation for Spatial Resolution Enhancement in Ultrasonic NDE Imaging

    SciTech Connect

    Clark, G A

    2004-06-25

    This report describes a signal processing algorithm and MATLAB software for improving spatial resolution in ultrasonic nondestructive evaluation (NDE) imaging of materials. Given a measured reflection signal and an associated reference signal, the algorithm produces an optimal least-squares estimate of the impulse response of the material under test. This estimated impulse response, when used in place of the raw reflection signal, enhances the spatial resolution of the ultrasonic measurements by removing distortion caused by the limited-bandwidth transducers and the materials under test. The theory behind the processing algorithms is briefly presented, while the reader is referred to the bibliography for details. The main focus of the report is to describe how to use the MATLAB software. Two processing examples using actual ultrasonic measurements are provided for tutorial purposes.

  11. Position-Controlled Data Acquisition Embedded System for Magnetic NDE of Bridge Stay Cables

    PubMed Central

    Maldonado-Lopez, Rocio; Christen, Rouven

    2011-01-01

    This work presents a custom-tailored sensing and data acquisition embedded system, designed to be integrated in a new magnetic NDE inspection device under development at Empa, a device intended for routine testing of large diameter bridge stay cables. The data acquisition (DAQ) system fulfills the speed and resolution requirements of the application and is able to continuously capture and store up to 2 GB of data at a sampling rate of 27 kS/s, with 12-bit resolution. This paper describes the DAQ system in detail, including both hardware and software implementation, as well as the key design challenges and the techniques employed to meet the specifications. Experimental results showing the performance of the system are also presented. PMID:22346572

  12. Development of high-energy neutron imaging for use in NDE applications

    SciTech Connect

    Dietrich, F; Hall, J; Logan, C; Schmid, G

    1999-06-01

    We are currently developing a high-energy (10 - 15 MeV) neutron imaging system for use in NDE applications. Our goal is to develop an imaging system capable of detecting cubic-mm-scale voids or other structural defects in heavily-shielded low-Z materials within thick sealed objects. The system will be relatively compact (suitable for use in a small laboratory) and capable of acquiring tomographic image data sets. The design of a prototype imaging detector and multi-axis staging system will be discussed and selected results from recent imaging experiments will be presented. The development of an intense, accelerator-driven neutron source suitable for use with the imaging system will also be discussed. Keywords: neutron imaging, neutron radiography, computed tomography, non-destructive inspection, neutron sources

  13. Position-controlled data acquisition embedded system for magnetic NDE of bridge stay cables.

    PubMed

    Maldonado-Lopez, Rocio; Christen, Rouven

    2011-01-01

    This work presents a custom-tailored sensing and data acquisition embedded system, designed to be integrated in a new magnetic NDE inspection device under development at Empa, a device intended for routine testing of large diameter bridge stay cables. The data acquisition (DAQ) system fulfills the speed and resolution requirements of the application and is able to continuously capture and store up to 2 GB of data at a sampling rate of 27 kS/s, with 12-bit resolution. This paper describes the DAQ system in detail, including both hardware and software implementation, as well as the key design challenges and the techniques employed to meet the specifications. Experimental results showing the performance of the system are also presented. PMID:22346572

  14. The Oral Speech Mechanism Screening Examination (OSMSE).

    ERIC Educational Resources Information Center

    St. Louis, Kenneth O.; Ruscello, Dennis M.

    Although speech-language pathologists are expected to be able to administer and interpret oral examinations, there are currently no screening tests available that provide careful administration instructions and data for intra-examiner and inter-examiner reliability. The Oral Speech Mechanism Screening Examination (OSMSE) is designed primarily for…

  15. Reliability Centered Maintenance - Methodologies

    NASA Technical Reports Server (NTRS)

    Kammerer, Catherine C.

    2009-01-01

    Journal article about Reliability Centered Maintenance (RCM) methodologies used by United Space Alliance, LLC (USA) in support of the Space Shuttle Program at Kennedy Space Center. The USA Reliability Centered Maintenance program differs from traditional RCM programs because various methodologies are utilized to take advantage of their respective strengths for each application. Based on operational experience, USA has customized the traditional RCM methodology into a streamlined lean logic path and has implemented the use of statistical tools to drive the process. USA RCM has integrated many of the L6S tools into both RCM methodologies. The tools utilized in the Measure, Analyze, and Improve phases of a Lean Six Sigma project lend themselves to application in the RCM process. All USA RCM methodologies meet the requirements defined in SAE JA 1011, Evaluation Criteria for Reliability-Centered Maintenance (RCM) Processes. The proposed article explores these methodologies.

  16. Software reliability perspectives

    NASA Technical Reports Server (NTRS)

    Wilson, Larry; Shen, Wenhui

    1987-01-01

    Software which is used in life critical functions must be known to be highly reliable before installation. This requires a strong testing program to estimate the reliability, since neither formal methods, software engineering nor fault tolerant methods can guarantee perfection. Prior to the final testing software goes through a debugging period and many models have been developed to try to estimate reliability from the debugging data. However, the existing models are poorly validated and often give poor performance. This paper emphasizes the fact that part of their failures can be attributed to the random nature of the debugging data given to these models as input, and it poses the problem of correcting this defect as an area of future research.

  17. Elucidating the relationship between DISC1, NDEL1 and NDE1 and the risk for schizophrenia: Evidence of epistasis and competitive binding

    PubMed Central

    Burdick, Katherine E.; Kamiya, Atsushi; Hodgkinson, Colin A.; Lencz, Todd; DeRosse, Pamela; Ishizuka, Koko; Elashvili, Sarah; Arai, Hiroyuki; Goldman, David; Sawa, Akira; Malhotra, Anil K.

    2008-01-01

    DISC1 influences susceptibility to psychiatric disease and related phenotypes. Intact functions of DISC1 and its binding partners, NDEL1 and NDE1, are critical to neurodevelopmental processes aberrant in schizophrenia (SZ). Despite evidence of an NDEL1–DISC1 protein interaction, there have been no investigations of the NDEL1 gene or the relationship between NDEL1 and DISC1 in SZ. We genotyped six NDEL1 single-nucleotide polymorphisms (SNPs) in 275 Caucasian SZ patients and 200 controls and tested for association and interaction between the functional SNP Ser704Cys in DISC1 and NDEL1. We also evaluated the relationship between NDE1 and DISC1 genotype and SZ. Finally, in a series of in vitro assays, we determined the binding profiles of NDEL1 and NDE1, in relation to DISC1 Ser704Cys. We observed a single haplotype block within NDEL1; the majority of variation was captured by NDEL1 rs1391768. We observed a significant interaction between rs1391768 and DISC1 Ser704Cys, with the effect of NDEL1 on SZ evident only against the background of DISC1 Ser704 homozygosity. Secondary analyses revealed no direct relationship between NDE1 genotype and SZ; however, there was an opposite pattern of risk for NDE1 genotype when conditioned on DISC1 Ser704Cys, with NDE1 rs3784859 imparting a significant effect but only in the context of a Cys-carrying background. In addition, we report opposing binding patterns of NDEL1 and NDE1 to Ser704 versus Cys704, at the same DISC1 binding domain. These data suggest that NDEL1 significantly influences risk for SZ via an interaction with DISC1. We propose a model where NDEL1 and NDE1 compete for binding with DISC1. PMID:18469341

  18. Gearbox Reliability Collaborative Update (Presentation)

    SciTech Connect

    Sheng, S.

    2013-10-01

    This presentation was given at the Sandia Reliability Workshop in August 2013 and provides information on current statistics, a status update, next steps, and other reliability research and development activities related to the Gearbox Reliability Collaborative.

  19. Materials reliability issues in microelectronics

    SciTech Connect

    Lloyd, J.R. ); Yost, F.G. ); Ho, P.S. )

    1991-01-01

    This book covers the proceedings of a MRS symposium on materials reliability in microelectronics. Topics include: electromigration; stress effects on reliability; stress and packaging; metallization; device, oxide and dielectric reliability; new investigative techniques; and corrosion.

  20. Nondestructive examination of the TRMM RCS propellant tanks

    NASA Technical Reports Server (NTRS)

    Free, James M.

    1993-01-01

    This paper assesses the feasibility of using eddy current nondestructive examination of determine flaw sizes in completely assembled hydrazine propellant tanks. The study was performed by the NASA Goddard Space Flight Center for the Tropical Rainfall Measuring Mission (TRMM) project to help determine whether existing propellant tanks could meet the fracture analysis requirements of the current pressure vessel specification, MIL-STD-1522A and, therefore be used on the TRMM spacecraft. After evaluating several nondestructive test methods, eddy current testing was selected as the most promising method for determining flaw sizes on external and internal surfaces of completely assembled tanks. Tests were conducted to confirm the detection capability of the eddy current NDE, procedures were developed to inspect two candidate tanks, and the test support equipment was designed. The non-spherical tank eddy current NDE test program was terminated when the decision was made to procure new tanks for the TRMM propulsion subsystem. The information on the development phase of this test program is presented in this paper as a reference for future investigation on the subject.

  1. Nondestructive examination of the TRMM RCS propellant tanks

    NASA Astrophysics Data System (ADS)

    Free, James M.

    1993-11-01

    This paper assesses the feasibility of using eddy current nondestructive examination of determine flaw sizes in completely assembled hydrazine propellant tanks. The study was performed by the NASA Goddard Space Flight Center for the Tropical Rainfall Measuring Mission (TRMM) project to help determine whether existing propellant tanks could meet the fracture analysis requirements of the current pressure vessel specification, MIL-STD-1522A and, therefore be used on the TRMM spacecraft. After evaluating several nondestructive test methods, eddy current testing was selected as the most promising method for determining flaw sizes on external and internal surfaces of completely assembled tanks. Tests were conducted to confirm the detection capability of the eddy current NDE, procedures were developed to inspect two candidate tanks, and the test support equipment was designed. The non-spherical tank eddy current NDE test program was terminated when the decision was made to procure new tanks for the TRMM propulsion subsystem. The information on the development phase of this test program is presented in this paper as a reference for future investigation on the subject.

  2. Designing reliability into accelerators

    SciTech Connect

    Hutton, A.

    1992-08-01

    For the next generation of high performance, high average luminosity colliders, the ``factories,`` reliability engineering must be introduced right at the inception of the project and maintained as a central theme throughout the project. There are several aspects which will be addressed separately: Concept; design; motivation; management techniques; and fault diagnosis.

  3. Designing reliability into accelerators

    SciTech Connect

    Hutton, A.

    1992-08-01

    For the next generation of high performance, high average luminosity colliders, the factories,'' reliability engineering must be introduced right at the inception of the project and maintained as a central theme throughout the project. There are several aspects which will be addressed separately: Concept; design; motivation; management techniques; and fault diagnosis.

  4. Software reliability report

    NASA Technical Reports Server (NTRS)

    Wilson, Larry

    1991-01-01

    There are many software reliability models which try to predict future performance of software based on data generated by the debugging process. Unfortunately, the models appear to be unable to account for the random nature of the data. If the same code is debugged multiple times and one of the models is used to make predictions, intolerable variance is observed in the resulting reliability predictions. It is believed that data replication can remove this variance in lab type situations and that it is less than scientific to talk about validating a software reliability model without considering replication. It is also believed that data replication may prove to be cost effective in the real world, thus the research centered on verification of the need for replication and on methodologies for generating replicated data in a cost effective manner. The context of the debugging graph was pursued by simulation and experimentation. Simulation was done for the Basic model and the Log-Poisson model. Reasonable values of the parameters were assigned and used to generate simulated data which is then processed by the models in order to determine limitations on their accuracy. These experiments exploit the existing software and program specimens which are in AIR-LAB to measure the performance of reliability models.

  5. Software Reliability Measurement Experience

    NASA Technical Reports Server (NTRS)

    Nikora, A. P.

    1993-01-01

    In this chapter, we describe a recent study of software reliability measurement methods that was conducted at the Jet Propulsion Laboratory. The first section of the chapter, sections 8.1, summarizes the study, characterizes the participating projects, describes the available data, and summarizes the tudy's results.

  6. Reliable solar cookers

    SciTech Connect

    Magney, G.K.

    1992-12-31

    The author describes the activities of SERVE, a Christian relief and development agency, to introduce solar ovens to the Afghan refugees in Pakistan. It has provided 5,000 solar cookers since 1984. The experience has demonstrated the potential of the technology and the need for a durable and reliable product. Common complaints about the cookers are discussed and the ideal cooker is described.

  7. Parametric Mass Reliability Study

    NASA Technical Reports Server (NTRS)

    Holt, James P.

    2014-01-01

    The International Space Station (ISS) systems are designed based upon having redundant systems with replaceable orbital replacement units (ORUs). These ORUs are designed to be swapped out fairly quickly, but some are very large, and some are made up of many components. When an ORU fails, it is replaced on orbit with a spare; the failed unit is sometimes returned to Earth to be serviced and re-launched. Such a system is not feasible for a 500+ day long-duration mission beyond low Earth orbit. The components that make up these ORUs have mixed reliabilities. Components that make up the most mass-such as computer housings, pump casings, and the silicon board of PCBs-typically are the most reliable. Meanwhile components that tend to fail the earliest-such as seals or gaskets-typically have a small mass. To better understand the problem, my project is to create a parametric model that relates both the mass of ORUs to reliability, as well as the mass of ORU subcomponents to reliability.

  8. Nonparametric Methods in Reliability

    PubMed Central

    Hollander, Myles; Peña, Edsel A.

    2005-01-01

    Probabilistic and statistical models for the occurrence of a recurrent event over time are described. These models have applicability in the reliability, engineering, biomedical and other areas where a series of events occurs for an experimental unit as time progresses. Nonparametric inference methods, in particular, the estimation of a relevant distribution function, are described. PMID:16710444

  9. The Validity and Reliability of the Mobbing Scale (MS)

    ERIC Educational Resources Information Center

    Yaman, Erkan

    2009-01-01

    The aim of this research is to develop the Mobbing Scale and examine its validity and reliability. The sample of the study consisted of 515 persons from Sakarya and Bursa. In this study, construct validity, internal consistency, test-retest reliability, and item analysis of the scale were examined. As a result of factor analysis for construct…

  10. Probabilistic fatigue methodology for six nines reliability

    NASA Technical Reports Server (NTRS)

    Everett, R. A., Jr.; Bartlett, F. D., Jr.; Elber, Wolf

    1990-01-01

    Fleet readiness and flight safety strongly depend on the degree of reliability that can be designed into rotorcraft flight critical components. The current U.S. Army fatigue life specification for new rotorcraft is the so-called six nines reliability, or a probability of failure of one in a million. The progress of a round robin which was established by the American Helicopter Society (AHS) Subcommittee for Fatigue and Damage Tolerance is reviewed to investigate reliability-based fatigue methodology. The participants in this cooperative effort are in the U.S. Army Aviation Systems Command (AVSCOM) and the rotorcraft industry. One phase of the joint activity examined fatigue reliability under uniquely defined conditions for which only one answer was correct. The other phases were set up to learn how the different industry methods in defining fatigue strength affected the mean fatigue life and reliability calculations. Hence, constant amplitude and spectrum fatigue test data were provided so that each participant could perform their standard fatigue life analysis. As a result of this round robin, the probabilistic logic which includes both fatigue strength and spectrum loading variability in developing a consistant reliability analysis was established. In this first study, the reliability analysis was limited to the linear cumulative damage approach. However, it is expected that superior fatigue life prediction methods will ultimately be developed through this open AHS forum. To that end, these preliminary results were useful in identifying some topics for additional study.

  11. Space Shuttle Propulsion System Reliability

    NASA Technical Reports Server (NTRS)

    Welzyn, Ken; VanHooser, Katherine; Moore, Dennis; Wood, David

    2011-01-01

    This session includes the following sessions: (1) External Tank (ET) System Reliability and Lessons, (2) Space Shuttle Main Engine (SSME), Reliability Validated by a Million Seconds of Testing, (3) Reusable Solid Rocket Motor (RSRM) Reliability via Process Control, and (4) Solid Rocket Booster (SRB) Reliability via Acceptance and Testing.

  12. Reliable broadcast protocols

    NASA Technical Reports Server (NTRS)

    Joseph, T. A.; Birman, Kenneth P.

    1989-01-01

    A number of broadcast protocols that are reliable subject to a variety of ordering and delivery guarantees are considered. Developing applications that are distributed over a number of sites and/or must tolerate the failures of some of them becomes a considerably simpler task when such protocols are available for communication. Without such protocols the kinds of distributed applications that can reasonably be built will have a very limited scope. As the trend towards distribution and decentralization continues, it will not be surprising if reliable broadcast protocols have the same role in distributed operating systems of the future that message passing mechanisms have in the operating systems of today. On the other hand, the problems of engineering such a system remain large. For example, deciding which protocol is the most appropriate to use in a certain situation or how to balance the latency-communication-storage costs is not an easy question.

  13. Data networks reliability

    NASA Astrophysics Data System (ADS)

    Gallager, Robert G.

    1988-10-01

    The research from 1984 to 1986 on Data Network Reliability had the objective of developing general principles governing the reliable and efficient control of data networks. The research was centered around three major areas: congestion control, multiaccess networks, and distributed asynchronous algorithms. The major topics within congestion control were the use of flow control algorithms. The major topics within congestion control were the use of flow control to reduce congestion and the use of routing to reduce congestion. The major topics within multiaccess networks were the communication properties of multiaccess channels, collision resolution, and packet radio networks. The major topics within asynchronous distributed algorithms were failure recovery, time vs. communication tradeoffs, and the general theory of distributed algorithms.

  14. Reliability of photovoltaic modules

    NASA Technical Reports Server (NTRS)

    Ross, R. G., Jr.

    1986-01-01

    In order to assess the reliability of photovoltaic modules, four categories of known array failure and degradation mechanisms are discussed, and target reliability allocations have been developed within each category based on the available technology and the life-cycle-cost requirements of future large-scale terrestrial applications. Cell-level failure mechanisms associated with open-circuiting or short-circuiting of individual solar cells generally arise from cell cracking or the fatigue of cell-to-cell interconnects. Power degradation mechanisms considered include gradual power loss in cells, light-induced effects, and module optical degradation. Module-level failure mechanisms and life-limiting wear-out mechanisms are also explored.

  15. Compact, Reliable EEPROM Controller

    NASA Technical Reports Server (NTRS)

    Katz, Richard; Kleyner, Igor

    2010-01-01

    A compact, reliable controller for an electrically erasable, programmable read-only memory (EEPROM) has been developed specifically for a space-flight application. The design may be adaptable to other applications in which there are requirements for reliability in general and, in particular, for prevention of inadvertent writing of data in EEPROM cells. Inadvertent writes pose risks of loss of reliability in the original space-flight application and could pose such risks in other applications. Prior EEPROM controllers are large and complex and do not provide all reasonable protections (in many cases, few or no protections) against inadvertent writes. In contrast, the present controller provides several layers of protection against inadvertent writes. The controller also incorporates a write-time monitor, enabling determination of trends in the performance of an EEPROM through all phases of testing. The controller has been designed as an integral subsystem of a system that includes not only the controller and the controlled EEPROM aboard a spacecraft but also computers in a ground control station, relatively simple onboard support circuitry, and an onboard communication subsystem that utilizes the MIL-STD-1553B protocol. (MIL-STD-1553B is a military standard that encompasses a method of communication and electrical-interface requirements for digital electronic subsystems connected to a data bus. MIL-STD- 1553B is commonly used in defense and space applications.) The intent was to both maximize reliability while minimizing the size and complexity of onboard circuitry. In operation, control of the EEPROM is effected via the ground computers, the MIL-STD-1553B communication subsystem, and the onboard support circuitry, all of which, in combination, provide the multiple layers of protection against inadvertent writes. There is no controller software, unlike in many prior EEPROM controllers; software can be a major contributor to unreliability, particularly in fault

  16. Spacecraft transmitter reliability

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A workshop on spacecraft transmitter reliability was held at the NASA Lewis Research Center on September 25 and 26, 1979, to discuss present knowledge and to plan future research areas. Since formal papers were not submitted, this synopsis was derived from audio tapes of the workshop. The following subjects were covered: users' experience with space transmitters; cathodes; power supplies and interfaces; and specifications and quality assurance. A panel discussion ended the workshop.

  17. Reliability and testing

    NASA Technical Reports Server (NTRS)

    Auer, Werner

    1996-01-01

    Reliability and its interdependence with testing are important topics for development and manufacturing of successful products. This generally accepted fact is not only a technical statement, but must be also seen in the light of 'Human Factors.' While the background for this paper is the experience gained with electromechanical/electronic space products, including control and system considerations, it is believed that the content could be also of interest for other fields.

  18. State of the Art Assessment of NDE Techniques for Aging Cable Management in Nuclear Power Plants FY2015

    SciTech Connect

    Glass, Samuel W.; Fifield, Leonard S.; Dib, Gerges; Tedeschi, Jonathan R.; Jones, Anthony M.; Hartman, Trenton S.

    2015-09-08

    This milestone report presents an update on the state-of-the-art review and research being conducted to identify key indicators of in-containment cable aging at nuclear power plants (NPPs), and devise in-situ measurement techniques that are sensitive to these key indicators. The motivation for this study stems from the need to address open questions related to nondestructive evaluation (NDE) of aging cables for degradation detection and estimation of condition-based remaining service life. These questions arise within the context of a second round of license extension for NPPs that would extend the operating license to 60 and 80 years. Within the introduction, a review of recently published U.S. and international research and guidance for cable aging management programs including NDE technologies is provided. As with any “state-of-the-art” report, the observations are deemed accurate as of the publication date but cannot anticipate evolution of the technology. Moreover, readers are advised that research and development of cable NDE technology is an ongoing issue of global concern.

  19. Non-contact main cable NDE technique for suspension bridge using magnetic flux-based B-H loop measurements

    NASA Astrophysics Data System (ADS)

    Park, Seunghee; Kim, Ju-Won; Moon, Dae-Joong

    2015-04-01

    In this study, a noncontact main cable NDE method has been developed. This cable NDE method utilizes the direct current (DC) magnetization and a searching coil-based total flux measurement. A total flux sensor head prototype was fabricated that consists of an electro-magnet yoke and a searching coil sensor. To obtain a B-H loop, a magnetic field was generated by applying a cycle of low frequency direct current to the electro-magnet yoke. During the magnetization, a search coil sensor measures the electromotive force from magnetized cable. During the magnetization process, a search coil sensor was measured the magnetic flux density. Total flux was calculated by integrating the measured magnetic flux using a fluxmeter. A B-H loop is obtained by using relationship between a cycle of input DC voltage and measured total flux. The B-H loop can reflect the property of the ferromagnetic materials. Therefore, the cross-sectional loss of cable can be detected using variation of features from the B-H curve. To verify the feasibility of the proposed steel cable NDE method, a series of experimental studies using a main-cable mock-up specimen has been performed in this study.

  20. Improving the reliability of automated non-destructive inspection

    SciTech Connect

    Brierley, N.; Tippetts, T.; Cawley, P.

    2014-02-18

    In automated NDE a region of an inspected component is often interrogated several times, be it within a single data channel, across multiple channels or over the course of repeated inspections. The systematic combination of these diverse readings is recognized to provide a means to improve the reliability of the inspection, for example by enabling noise suppression. Specifically, such data fusion makes it possible to declare regions of the component defect-free to a very high probability whilst readily identifying indications. Registration, aligning input datasets to a common coordinate system, is a critical pre-computation before meaningful data fusion takes place. A novel scheme based on a multiobjective optimization is described. The developed data fusion framework, that is able to identify and rate possible indications in the dataset probabilistically, based on local data statistics, is outlined. The process is demonstrated on large data sets from the industrial ultrasonic testing of aerospace turbine disks, with major improvements in the probability of detection and probability of false call being obtained.

  1. Ultrasonic inspection reliability for intergranular stress corrosion cracks

    SciTech Connect

    Heasler, P G; Taylor, T T; Spanner, J C; Doctor, S R; Deffenbaugh, J D

    1990-07-01

    A pipe inspection round robin entitled Mini-Round Robin'' was conducted at Pacific Northwest Laboratory from May 1985 through October 1985. The research was sponsored by the US Nuclear Regulatory Commission, Office of Nuclear Regulatory Research under a program entitled Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactors.'' The Mini-Round Robin (MRR) measured the intergranular stress corrosion (GSC) crack detection and sizing capabilities of inservice inspection (ISI) inspectors that had passed the requirements of IEB 83-02 and the Electric Power Research Institute (EPRI) sizing training course. The MRR data base was compared with an earlier Pipe Inspection Round Robin (PIRR) that had measured the performance of inservice inspection prior to 1982. Comparison of the MRR and PIRR data bases indicates no significant change in the inspection capability for detecting IGSCC. Also, when comparing detection of long and short cracks, no difference in detection capability was measured. An improvement in the ability to differentiate between shallow and deeper IGSCC was found when the MRR sizing capability was compared with an earlier sizing round robin conducted by the EPRI. In addition to the pipe inspection round robin, a human factors study was conducted in conjunction with the Mini-Round Robin. The most important result of the human factors study is that the Relative Operating Characteristics (ROC) curves provide a better methodology for describing inspector performance than only probability of detection (POD) or single-point crack/no crack data. 6 refs., 55 figs., 18 tabs.

  2. Software reliability studies

    NASA Technical Reports Server (NTRS)

    Hoppa, Mary Ann; Wilson, Larry W.

    1994-01-01

    There are many software reliability models which try to predict future performance of software based on data generated by the debugging process. Our research has shown that by improving the quality of the data one can greatly improve the predictions. We are working on methodologies which control some of the randomness inherent in the standard data generation processes in order to improve the accuracy of predictions. Our contribution is twofold in that we describe an experimental methodology using a data structure called the debugging graph and apply this methodology to assess the robustness of existing models. The debugging graph is used to analyze the effects of various fault recovery orders on the predictive accuracy of several well-known software reliability algorithms. We found that, along a particular debugging path in the graph, the predictive performance of different models can vary greatly. Similarly, just because a model 'fits' a given path's data well does not guarantee that the model would perform well on a different path. Further we observed bug interactions and noted their potential effects on the predictive process. We saw that not only do different faults fail at different rates, but that those rates can be affected by the particular debugging stage at which the rates are evaluated. Based on our experiment, we conjecture that the accuracy of a reliability prediction is affected by the fault recovery order as well as by fault interaction.

  3. General Aviation Aircraft Reliability Study

    NASA Technical Reports Server (NTRS)

    Pettit, Duane; Turnbull, Andrew; Roelant, Henk A. (Technical Monitor)

    2001-01-01

    This reliability study was performed in order to provide the aviation community with an estimate of Complex General Aviation (GA) Aircraft System reliability. To successfully improve the safety and reliability for the next generation of GA aircraft, a study of current GA aircraft attributes was prudent. This was accomplished by benchmarking the reliability of operational Complex GA Aircraft Systems. Specifically, Complex GA Aircraft System reliability was estimated using data obtained from the logbooks of a random sample of the Complex GA Aircraft population.

  4. Improving the Reliability of Course Pretests.

    ERIC Educational Resources Information Center

    Garvin, Alfred D.; Ralston, Nancy C.

    Confidence Weighting (CW), after Ebel, and Multiple Responding (MR), after Coombs, are compared empirically to determine which improved test reliability more in the case of a course pretest derived from the final examination. It was hypothesized that MR, which purportedly measures partial knowledge, would be more effective than CW, which measures…

  5. Reliability of Multi-Category Rating Scales

    ERIC Educational Resources Information Center

    Parker, Richard I.; Vannest, Kimberly J.; Davis, John L.

    2013-01-01

    The use of multi-category scales is increasing for the monitoring of IEP goals, classroom and school rules, and Behavior Improvement Plans (BIPs). Although they require greater inference than traditional data counting, little is known about the inter-rater reliability of these scales. This simulation study examined the performance of nine…

  6. A reliability analysis of the revised competitiveness index.

    PubMed

    Harris, Paul B; Houston, John M

    2010-06-01

    This study examined the reliability of the Revised Competitiveness Index by investigating the test-retest reliability, interitem reliability, and factor structure of the measure based on a sample of 280 undergraduates (200 women, 80 men) ranging in age from 18 to 28 years (M = 20.1, SD = 2.1). The findings indicate that the Revised Competitiveness Index has high test-retest reliability, high inter-item reliability, and a stable factor structure. The results support the assertion that the Revised Competitiveness Index assesses competitiveness as a stable trait rather than a dynamic state. PMID:20712175

  7. Reliability Sensitivity for ROTOR-STATOR Systems with Rubbing

    NASA Astrophysics Data System (ADS)

    Zhang, Y. M.; Wen, B. C.; Liu, Q. L.

    2003-01-01

    On the basis of the dynamic equations of the Jeffcott rotor-stator model with imbalance, the reliability sensitivity of the rotor-stator systems with rubbing is examined. A statistical fourth moment method is developed to determine the first four moments of system response and state function. The distribution function of the system state function is approximately determined by the standard normal distribution functions using the Edgeworth series technique. The reliability and reliability sensitivity are obtained and the effect on reliability and reliability sensitivity of shaft stiffness and damping, stator stiffness and damping, radial clearance and stator radial stiffness is studied. Numerical results are also presented and discussed.

  8. Perceptions of Trust in Public Examinations

    ERIC Educational Resources Information Center

    Simpson, Lucy; Baird, Jo-Anne

    2013-01-01

    Over recent years, the credibility of public examinations in England has increasingly come to the fore. Government agencies have invested time and money into researching public perceptions of the reliability and validity of examinations. Whilst such research overlaps into the conceptual domain of trust, trust in examinations remains an elusive…

  9. Software reliability modeling and analysis

    NASA Technical Reports Server (NTRS)

    Scholz, F.-W.

    1986-01-01

    A discrete and, as approximation to it, a continuous model for the software reliability growth process are examined. The discrete model is based on independent multinomial trials and concerns itself with the joint distribution of the first occurrence time of its underlying events (bugs). The continuous model is based on the order statistics of N independent nonidentically distributed exponential random variables. It is shown that the spacings between bugs are not necessarily independent or exponentially (geometrically) distributed. However, there is a statistical rationale for viewing them so conditionally. Some identifiability problems are pointed out and resolved. In particular, it appears that the number of bugs in a program is not identifiable. Estimated upper bounds and confidence bounds for the residual program eror content are given based on the spacings of the first k bugs removed.

  10. Multi-Disciplinary System Reliability Analysis

    NASA Technical Reports Server (NTRS)

    Mahadevan, Sankaran; Han, Song

    1997-01-01

    The objective of this study is to develop a new methodology for estimating the reliability of engineering systems that encompass multiple disciplines. The methodology is formulated in the context of the NESSUS probabilistic structural analysis code developed under the leadership of NASA Lewis Research Center. The NESSUS code has been successfully applied to the reliability estimation of a variety of structural engineering systems. This study examines whether the features of NESSUS could be used to investigate the reliability of systems in other disciplines such as heat transfer, fluid mechanics, electrical circuits etc., without considerable programming effort specific to each discipline. In this study, the mechanical equivalence between system behavior models in different disciplines are investigated to achieve this objective. A new methodology is presented for the analysis of heat transfer, fluid flow, and electrical circuit problems using the structural analysis routines within NESSUS, by utilizing the equivalence between the computational quantities in different disciplines. This technique is integrated with the fast probability integration and system reliability techniques within the NESSUS code, to successfully compute the system reliability of multi-disciplinary systems. Traditional as well as progressive failure analysis methods for system reliability estimation are demonstrated, through a numerical example of a heat exchanger system involving failure modes in structural, heat transfer and fluid flow disciplines.

  11. Reliability improvement of distribution systems using SSVR.

    PubMed

    Hosseini, Mehdi; Shayanfar, Heidar Ali; Fotuhi-Firuzabad, Mahmoud

    2009-01-01

    This paper presents a reliability assessment algorithm for distribution systems using a Static Series Voltage Regulator (SSVR). Furthermore, this algorithm considers the effects of Distributed Generation (DG) units, alternative sources, system reconfiguration, load shedding and load adding on distribution system reliability indices. In this algorithm, load points are classified into 8 types and separated restoration times are considered for each class. Comparative studies are conducted to investigate the impacts of DG and alternative source unavailability on the distribution system reliability. For reliability assessment, the customer-oriented reliability indices such as SAIFI, SAIDI, CAIDI ASUI and also load- and energy-oriented indices such as ENS and AENS are evaluated. The effectiveness of the proposed algorithm is examined on the two standard distribution systems consisting of 33 and 69 nodes. The best location of the SSVR in distribution systems is determined based on different reliability indices, separately. Results show that the proposed algorithm is efficient for large-scale radial distribution systems and can accommodate the effects of fault isolation and load restoration. PMID:19006802

  12. Ultimately Reliable Pyrotechnic Systems

    NASA Technical Reports Server (NTRS)

    Scott, John H.; Hinkel, Todd

    2015-01-01

    This paper presents the methods by which NASA has designed, built, tested, and certified pyrotechnic devices for high reliability operation in extreme environments and illustrates the potential applications in the oil and gas industry. NASA's extremely successful application of pyrotechnics is built upon documented procedures and test methods that have been maintained and developed since the Apollo Program. Standards are managed and rigorously enforced for performance margins, redundancy, lot sampling, and personnel safety. The pyrotechnics utilized in spacecraft include such devices as small initiators and detonators with the power of a shotgun shell, detonating cord systems for explosive energy transfer across many feet, precision linear shaped charges for breaking structural membranes, and booster charges to actuate valves and pistons. NASA's pyrotechnics program is one of the more successful in the history of Human Spaceflight. No pyrotechnic device developed in accordance with NASA's Human Spaceflight standards has ever failed in flight use. NASA's pyrotechnic initiators work reliably in temperatures as low as -420 F. Each of the 135 Space Shuttle flights fired 102 of these initiators, some setting off multiple pyrotechnic devices, with never a failure. The recent landing on Mars of the Opportunity rover fired 174 of NASA's pyrotechnic initiators to complete the famous '7 minutes of terror.' Even after traveling through extreme radiation and thermal environments on the way to Mars, every one of them worked. These initiators have fired on the surface of Titan. NASA's design controls, procedures, and processes produce the most reliable pyrotechnics in the world. Application of pyrotechnics designed and procured in this manner could enable the energy industry's emergency equipment, such as shutoff valves and deep-sea blowout preventers, to be left in place for years in extreme environments and still be relied upon to function when needed, thus greatly enhancing

  13. CR reliability testing

    NASA Astrophysics Data System (ADS)

    Honeyman-Buck, Janice C.; Rill, Lynn; Frost, Meryll M.; Staab, Edward V.

    1998-07-01

    The purpose of this work was to develop a method for systematically testing the reliability of a CR system under realistic daily loads in a non-clinical environment prior to its clinical adoption. Once digital imaging replaces film, it will be very difficult to revert back should the digital system become unreliable. Prior to the beginning of the test, a formal evaluation was performed to set the benchmarks for performance and functionality. A formal protocol was established that included all the 62 imaging plates in the inventory for each 24-hour period in the study. Imaging plates were exposed using different combinations of collimation, orientation, and SID. Anthropomorphic phantoms were used to acquire images of different sizes. Each combination was chosen randomly to simulate the differences that could occur in clinical practice. The tests were performed over a wide range of times with batches of plates processed to simulate the temporal constraints required by the nature of portable radiographs taken in the Intensive Care Unit (ICU). Current patient demographics were used for the test studies so automatic routing algorithms could be tested. During the test, only three minor reliability problems occurred, two of which were not directly related to the CR unit. One plate was discovered to cause a segmentation error that essentially reduced the image to only black and white with no gray levels. This plate was removed from the inventory to be replaced. Another problem was a PACS routing problem that occurred when the DICOM server with which the CR was communicating had a problem with disk space. The final problem was a network printing failure to the laser cameras. Although the units passed the reliability test, problems with interfacing to workstations were discovered. The two issues that were identified were the interpretation of what constitutes a study for CR and the construction of the look-up table for a proper gray scale display.

  14. Reliable VLSI sequential controllers

    NASA Technical Reports Server (NTRS)

    Whitaker, S.; Maki, G.; Shamanna, M.

    1990-01-01

    A VLSI architecture for synchronous sequential controllers is presented that has attractive qualities for producing reliable circuits. In these circuits, one hardware implementation can realize any flow table with a maximum of 2(exp n) internal states and m inputs. Also all design equations are identical. A real time fault detection means is presented along with a strategy for verifying the correctness of the checking hardware. This self check feature can be employed with no increase in hardware. The architecture can be modified to achieve fail safe designs. With no increase in hardware, an adaptable circuit can be realized that allows replacement of faulty transitions with fault free transitions.

  15. Ferrite logic reliability study

    NASA Technical Reports Server (NTRS)

    Baer, J. A.; Clark, C. B.

    1973-01-01

    Development and use of digital circuits called all-magnetic logic are reported. In these circuits the magnetic elements and their windings comprise the active circuit devices in the logic portion of a system. The ferrite logic device belongs to the all-magnetic class of logic circuits. The FLO device is novel in that it makes use of a dual or bimaterial ferrite composition in one physical ceramic body. This bimaterial feature, coupled with its potential for relatively high speed operation, makes it attractive for high reliability applications. (Maximum speed of operation approximately 50 kHz.)

  16. Fault Tree Reliability Analysis and Design-for-reliability

    Energy Science and Technology Software Center (ESTSC)

    1998-05-05

    WinR provides a fault tree analysis capability for performing systems reliability and design-for-reliability analyses. The package includes capabilities for sensitivity and uncertainity analysis, field failure data analysis, and optimization.

  17. On Component Reliability and System Reliability for Space Missions

    NASA Technical Reports Server (NTRS)

    Chen, Yuan; Gillespie, Amanda M.; Monaghan, Mark W.; Sampson, Michael J.; Hodson, Robert F.

    2012-01-01

    This paper is to address the basics, the limitations and the relationship between component reliability and system reliability through a study of flight computing architectures and related avionics components for NASA future missions. Component reliability analysis and system reliability analysis need to be evaluated at the same time, and the limitations of each analysis and the relationship between the two analyses need to be understood.

  18. Integrated circuit reliability testing

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G. (Inventor); Sayah, Hoshyar R. (Inventor)

    1990-01-01

    A technique is described for use in determining the reliability of microscopic conductors deposited on an uneven surface of an integrated circuit device. A wafer containing integrated circuit chips is formed with a test area having regions of different heights. At the time the conductors are formed on the chip areas of the wafer, an elongated serpentine assay conductor is deposited on the test area so the assay conductor extends over multiple steps between regions of different heights. Also, a first test conductor is deposited in the test area upon a uniform region of first height, and a second test conductor is deposited in the test area upon a uniform region of second height. The occurrence of high resistances at the steps between regions of different height is indicated by deriving the measured length of the serpentine conductor using the resistance measured between the ends of the serpentine conductor, and comparing that to the design length of the serpentine conductor. The percentage by which the measured length exceeds the design length, at which the integrated circuit will be discarded, depends on the required reliability of the integrated circuit.

  19. Integrated circuit reliability testing

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G. (Inventor); Sayah, Hoshyar R. (Inventor)

    1988-01-01

    A technique is described for use in determining the reliability of microscopic conductors deposited on an uneven surface of an integrated circuit device. A wafer containing integrated circuit chips is formed with a test area having regions of different heights. At the time the conductors are formed on the chip areas of the wafer, an elongated serpentine assay conductor is deposited on the test area so the assay conductor extends over multiple steps between regions of different heights. Also, a first test conductor is deposited in the test area upon a uniform region of first height, and a second test conductor is deposited in the test area upon a uniform region of second height. The occurrence of high resistances at the steps between regions of different height is indicated by deriving the measured length of the serpentine conductor using the resistance measured between the ends of the serpentine conductor, and comparing that to the design length of the serpentine conductor. The percentage by which the measured length exceeds the design length, at which the integrated circuit will be discarded, depends on the required reliability of the integrated circuit.

  20. Load Control System Reliability

    SciTech Connect

    Trudnowski, Daniel

    2015-04-03

    This report summarizes the results of the Load Control System Reliability project (DOE Award DE-FC26-06NT42750). The original grant was awarded to Montana Tech April 2006. Follow-on DOE awards and expansions to the project scope occurred August 2007, January 2009, April 2011, and April 2013. In addition to the DOE monies, the project also consisted of matching funds from the states of Montana and Wyoming. Project participants included Montana Tech; the University of Wyoming; Montana State University; NorthWestern Energy, Inc., and MSE. Research focused on two areas: real-time power-system load control methodologies; and, power-system measurement-based stability-assessment operation and control tools. The majority of effort was focused on area 2. Results from the research includes: development of fundamental power-system dynamic concepts, control schemes, and signal-processing algorithms; many papers (including two prize papers) in leading journals and conferences and leadership of IEEE activities; one patent; participation in major actual-system testing in the western North American power system; prototype power-system operation and control software installed and tested at three major North American control centers; and, the incubation of a new commercial-grade operation and control software tool. Work under this grant certainly supported the DOE-OE goals in the area of “Real Time Grid Reliability Management.”

  1. Understanding the Elements of Operational Reliability: A Key for Achieving High Reliability

    NASA Technical Reports Server (NTRS)

    Safie, Fayssal M.

    2010-01-01

    This viewgraph presentation reviews operational reliability and its role in achieving high reliability through design and process reliability. The topics include: 1) Reliability Engineering Major Areas and interfaces; 2) Design Reliability; 3) Process Reliability; and 4) Reliability Applications.

  2. Evaluation of sonic IR for NDE at Lawrence Livermore National Laboratory

    SciTech Connect

    Miller, W O

    2001-02-01

    Sonic IR was evaluated as an NDE technique at LLNL using a commercial ThermoSoniX system from Indigo Systems Corp. The main effort was to detect small cracks in aluminum oxide, a dense stiff ceramic. Test coupons were made containing 0.2-mm cracks by surface grinding, 1-mm cracks by compression with a Vickers bit, and 4-mm cracks by 3-point bending. Only the 3-point bend cracks produced thermal images. Several parts shattered during testing, perhaps by being forced at resonance by the 20-kHz acoustic probe. Tests on damaged carbon composite coupons produced thermal images that were in excellent agreement with ultrasonic inspection. The composite results also showed some dependence on contact location of the acoustic probe, and on the method of support. Tests on glass with surface damage produced weak images at the pits. Tests on metal ballistic targets produced thermal images at the impact sites. Modal analyses suggest that the input frequency should be matched to the desired response, and also that forced resonance damaged some parts.

  3. In-Situ NDE Characterization of Kevlar and Carbon Composite Micromechanics for Improved COPV Health Monitoring

    NASA Technical Reports Server (NTRS)

    Waller, Jess M.; Saulsberry, Regor L.

    2009-01-01

    This project is a subtask of a multi-center project to advance the state-of-the-art by developing NDE techniques that are capable of evaluating stress rupture (SR) degradation in Kevlar/epoxy (K/Ep) composite overwrapped pressure vessels (COPVs), and damage progression in carbon/epoxy (C/Ep) COPVs. In this subtask, acoustic emission (AE) data acquired during intermittent load hold tensile testing of K/Ep and C/Ep composite tow materials-of-construction used in COPV fabrication were analyzed to monitor progressive damage during the approach to tensile failure. Insight into the progressive damage of composite tow was gained by monitoring AE event rate, energy, source location, and frequency. Source location based on arrival time data was used to discern between significant AE attributable to microstructural damage and spurious AE attributable to background and grip noise. One of the significant findings was the observation of increasing violation of the Kaiser effect (Felicity ratio < 1.0) with damage accumulation.

  4. An exploration of the utilities of terahertz waves for the NDE of composites

    SciTech Connect

    Hsu, David K.; Im, Kwang-Hee; Chiou, Chien-Ping; Barnard, Daniel J.

    2011-06-23

    We report an investigation of terahertz waves for the nondestructive evaluation of composite materials and structures. The modalities of the terahertz radiation used were time domain spectroscopy (TDS) and continuous wave (CW). The composite materials and structures investigated include both non-conducting polymeric composites and carbon fiber composites. Terahertz signals in the TDS mode resembles that of ultrasound; however, unlike ultrasound, a terahertz pulse can detect a crack hidden behind a larger crack. This was demonstrated in thick GFRP laminates containing double saw slots. In carbon composites the penetration of terahertz waves is quite limited and the detection of flaws is strongly affected by the angle between the electric field vector of the terahertz waves and the intervening fiber directions. The structures tested in this study include both solid laminates and honeycomb sandwiches. The defects and anomalies investigated by terahertz waves were foreign material inclusions, simulated disbond and delamination, mechanical impact damage, heat damage, and water or hydraulic fluid ingression. The effectiveness and limitations of terahertz radiation for the NDE of composites are discussed.

  5. Advancements in NDE for utilities and the petrochemical industry through electromagnetic acoustic transducers (EMATs)

    NASA Astrophysics Data System (ADS)

    Robertson, M. O.; Stevens, Donald M.; Schlader, Daniel M.; Tilley, Richard M.

    1998-03-01

    The ultrasonic testing (UT) method continues to broaden in its effectiveness and capabilities for nondestructive evaluation (NDE). Much of this expansion can be attributed to advancements in specific techniques of the method. The utilization of electromagnetic acoustic transducers (EMATs) in dedicated ultrasonic systems has provided McDermott Technology, Inc. (MTI), formerly Babcock & Wilcox, with significant advantages over conventional ultrasonics. In recent years, through significant R&D, MTI has been instrumental in bringing about considerable advancements in the maturing EMAT technology. Progress in electronic design, magnet configurations, and sensor concepts has greatly improved system capabilities while reducing cost and equipment size. These improvements, coupled with the inherent advantages of utilizing the non-contact EMAT technique, have combined to make this technology a viable option for many commercial system inspection applications. MTI has recently completed the development and commercialization of an EMAT-based UT scanner for boiler tube thickness measurements. MTI is currently developing an automated EMAT scanner, based on phased array technology, for complete volumetric inspection of circumferential girth welds associated with pipelines (intended primarily for offshore applications). Additional benefits of phased array technology for providing materials characterization are currently being researched.

  6. Combined investigation of Eddy current and ultrasonic techniques for composite materials NDE

    SciTech Connect

    Davis, C.W.; Nath, S.; Fulton, J.P.; Namkung, M.

    1993-12-31

    Advanced composites are not without trade-offs. Their increased designability brings an increase in the complexity of their internal geometry and, as a result, an increase in the number of failure modes associated with a defect. When two or more isotropic materials are combined in a composite, the isotropic material failure modes may also combine. In a laminate, matrix delamination, cracking and crazing, and voids and porosity, will often combine with fiber breakage, shattering, waviness, and separation to bring about ultimate structural failure. This combining of failure modes can result in defect boundaries of different sizes, corresponding to the failure of each structural component. This paper discusses a dual-technology NDE (Non Destructive Evaluation) (eddy current (EC) and ultrasonics (UT)) study of graphite/epoxy (gr/ep) laminate samples. Eddy current and ultrasonic raster (Cscan) imaging were used together to characterize the effects of mechanical impact damage, high temperature thermal damage and various types of inserts in gr/ep laminate samples of various stacking sequences.

  7. Combined investigation of Eddy current and ultrasonic techniques for composite materials NDE

    NASA Technical Reports Server (NTRS)

    Davis, C. W.; Nath, S.; Fulton, J. P.; Namkung, M.

    1993-01-01

    Advanced composites are not without trade-offs. Their increased designability brings an increase in the complexity of their internal geometry and, as a result, an increase in the number of failure modes associated with a defect. When two or more isotropic materials are combined in a composite, the isotropic material failure modes may also combine. In a laminate, matrix delamination, cracking and crazing, and voids and porosity, will often combine with fiber breakage, shattering, waviness, and separation to bring about ultimate structural failure. This combining of failure modes can result in defect boundaries of different sizes, corresponding to the failure of each structural component. This paper discusses a dual-technology NDE (Non Destructive Evaluation) (eddy current (EC) and ultrasonics (UT)) study of graphite/epoxy (gr/ep) laminate samples. Eddy current and ultrasonic raster (Cscan) imaging were used together to characterize the effects of mechanical impact damage, high temperature thermal damage and various types of inserts in gr/ep laminate samples of various stacking sequences.

  8. Evaluation of sonic IR for NDE at Lawrence Livermore National Laboratory

    NASA Astrophysics Data System (ADS)

    Miller, Wayne O.

    2001-03-01

    Sonic IR was evaluated as an NDE technique at LLNL using a commercial ThermoSoniX system from Indigo Systems Corp. The main effort was to detect small cracks in aluminum oxide, a dense stiff ceramic. Test coupons were made containing 0.2- mm cracks by surface grinding, 1-mm cracks by compression with a Vickers bit, and 4-mm cracks by 3-point bending. Only the 3-point bend cracks produced thermal images. Several parts shattered during testing, perhaps by being forced at resonance by the 20-kHz acoustic probe. Tests on damaged carbon composite coupons produced thermal images that were in excellent agreement with ultrasonic inspection. The composite results also showed some dependence on contact location of the acoustic probe, and on the method of support. Tests on glass with surface damage produced weak images at the pits. Tests on metal ballistic targets produced thermal images at the impact sites. Modal analyses suggest that the input frequency should be matched to the desired response, and also that forced resonance damaged some parts.

  9. Modeling of ray paths of head waves on irregular interfaces in TOFD inspection for NDE.

    PubMed

    Ferrand, A; Darmon, M; Chatillon, S; Deschamps, M

    2014-09-01

    The TOFD (Time of Flight Diffraction) technique is a classical ultrasonic inspection method used in ultrasonic non-destructive evaluation (NDE). This inspection technique is based on an arrangement of two probes of opposite beam directions and allows a precise positioning and a quantitative evaluation of the size of cracks contained in the inspected material thanks to their edges diffraction echoes. Among the typical phenomena arising for such an arrangement, head waves, which propagate along the specimen surface and are chronologically the first waves reaching the receiver, are notably observed. Head wave propagation on planar surfaces in TOFD configurations is well known. However, realistic inspection configurations often involve components with irregular surfaces, like steel excavated specimens. Surface irregularity is responsible for numerous effects on the scattering of bulk waves, causing the melting of surface and bulk mechanisms in the head wave propagation. In order to extend the classical ray approach on these complex cases, a generic algorithm of ray tracing between interface points (GIRT) has been designed. With respect to time of flight minimization (i.e. the Generalized Fermat's Principle), ray paths can be computed by GIRT for different natures of waves scattered by the complex surfaces or by flaws. The head wave fronts computed by GIRT are notably in good agreement with FEM simulated results. This algorithm, based on pure kinematic analysis of waves propagation, represents a first step in the future development of a complete ray theory for head waves simulation on irregular interfaces. PMID:24388406

  10. An Exploration of the Utilities of Terahertz Waves for the Nde of Composites

    NASA Astrophysics Data System (ADS)

    Hsu, David K.; Im, Kwang-Hee; Chiou, Chien-Ping; Barnard, Daniel J.

    2011-06-01

    We report an investigation of terahertz waves for the nondestructive evaluation of composite materials and structures. The modalities of the terahertz radiation used were time domain spectroscopy (TDS) and continuous wave (CW). The composite materials and structures investigated include both non-conducting polymeric composites and carbon fiber composites. Terahertz signals in the TDS mode resembles that of ultrasound; however, unlike ultrasound, a terahertz pulse can detect a crack hidden behind a larger crack. This was demonstrated in thick GFRP laminates containing double saw slots. In carbon composites the penetration of terahertz waves is quite limited and the detection of flaws is strongly affected by the angle between the electric field vector of the terahertz waves and the intervening fiber directions. The structures tested in this study include both solid laminates and honeycomb sandwiches. The defects and anomalies investigated by terahertz waves were foreign material inclusions, simulated disbond and delamination, mechanical impact damage, heat damage, and water or hydraulic fluid ingression. The effectiveness and limitations of terahertz radiation for the NDE of composites are discussed.

  11. Material property relationships for pipeline steels and the potential for application of NDE

    NASA Astrophysics Data System (ADS)

    Smart, Lucinda; Bond, Leonard J.

    2016-02-01

    The oil and gas industry in the USA has an extensive infrastructure of pipelines, 70% of which were installed prior to 1980, and almost half were installed during the 1950s and 1960s. Ideally the mechanical properties (i.e. yield strength, tensile strength, transition temperature, and fracture toughness) of a steel pipe must be known in order to respond to detected defects in an appropriate manner. Neither current in-ditch methods nor the ILI inspection data have yet determined and map the desired mechanical properties with adequate confidence. In the quest to obtain the mechanical properties of a steel pipe using a nondestructive method, it is important to understand that there are many inter-related variables. This paper reports a literature review and an analysis of a sample set of data. There is promise for correlating the results of NDE measurement modalities to the information required to develop relationships between those measurements and the mechanical measurements desired for pipelines to ensure proper response to defects which are of significant threat.

  12. Issues in providing a reliable multicast facility

    NASA Technical Reports Server (NTRS)

    Dempsey, Bert J.; Strayer, W. Timothy; Weaver, Alfred C.

    1990-01-01

    Issues involved in point-to-multipoint communication are presented and the literature for proposed solutions and approaches surveyed. Particular attention is focused on the ideas and implementations that align with the requirements of the environment of interest. The attributes of multicast receiver groups that might lead to useful classifications, what the functionality of a management scheme should be, and how the group management module can be implemented are examined. The services that multicasting facilities can offer are presented, followed by mechanisms within the communications protocol that implements these services. The metrics of interest when evaluating a reliable multicast facility are identified and applied to four transport layer protocols that incorporate reliable multicast.

  13. Formal methods and software reliability

    NASA Technical Reports Server (NTRS)

    Holzmann, Gerard J.

    2004-01-01

    In this position statement I briefly describe how the software reliability problem has changed over the years, and the primary reasons for the recent creation of the Laboratory for Reliable Software at JPL.

  14. On-Line Nondestructive Methods for Examining Fuel Particles

    SciTech Connect

    Pardini, Allan F.; Bond, Leonard J.; Good, Morris S.; Bunch, Kyle J.; Sandness, Gerald A.; Hockey, Ronald L.; Saurwein, John J.; Gray, Joseph N.

    2007-09-15

    Tri-isotropic (TRISO) particle fuels, being considered for use in various advanced nuclear power reactors, consist of sub-millimeter diameter uranium oxide spheres uniformly coated to prevent the release of fission products into the reactor. About 15 billion of these spheres are needed to fuel a single reactor. Current quality control (QC) methods are manual, can destroy test specimens, and are not economically feasible. Replacing these methods with nondestructive evaluation (NDE) techniques, automated for higher speed, will make fuel production and reactor operation economically feasible, considering the requirement for extremely large fuel particle throughput rates. This paper reports a project to develop and demonstrate nondestructive examination methods to detect and reject defective particles, and in particular progress made in the final year of a Nuclear Energy Research Initiative (NERI) project . The work explored adapting, developing, and demonstrating innovative nondestructive test methods to cost-effectively assure the quality of large percentages of the fuel particles.

  15. Evaluation of MHTGR fuel reliability

    SciTech Connect

    Wichner, R.P.; Barthold, W.P.

    1992-07-01

    Modular High-Temperature Gas-Cooled Reactor (MHTGR) concepts that house the reactor vessel in a tight but unsealed reactor building place heightened importance on the reliability of the fuel particle coatings as fission product barriers. Though accident consequence analyses continue to show favorable results, the increased dependence on one type of barrier, in addition to a number of other factors, has caused the Nuclear Regulatory Commission (NRC) to consider conservative assumptions regarding fuel behavior. For this purpose, the concept termed ``weak fuel`` has been proposed on an interim basis. ``Weak fuel`` is a penalty imposed on consequence analyses whereby the fuel is assumed to respond less favorably to environmental conditions than predicted by behavioral models. The rationale for adopting this penalty, as well as conditions that would permit its reduction or elimination, are examined in this report. The evaluation includes an examination of possible fuel-manufacturing defects, quality-control procedures for defect detection, and the mechanisms by which fuel defects may lead to failure.

  16. Further discussion on reliability: the art of reliability estimation.

    PubMed

    Yang, Yanyun; Green, Samuel B

    2015-01-01

    Sijtsma and van der Ark (2015) focused in their lead article on three frameworks for reliability estimation in nursing research: classical test theory (CTT), factor analysis (FA), and generalizability theory. We extend their presentation with particular attention to CTT and FA methods. We first consider the potential of yielding an overly negative or an overly positive assessment of reliability based on coefficient alpha. Next, we discuss other CTT methods for estimating reliability and how the choice of methods affects the interpretation of the reliability coefficient. Finally, we describe FA methods, which not only permit an understanding of a measure's underlying structure but also yield a variety of reliability coefficients with different interpretations. On a more general note, we discourage reporting reliability as a two-choice outcome--unsatisfactory or satisfactory; rather, we recommend that nursing researchers make a conceptual and empirical argument about when a measure might be more or less reliable, depending on its use. PMID:25738627

  17. Making Reliability Arguments in Classrooms

    ERIC Educational Resources Information Center

    Parkes, Jay; Giron, Tilia

    2006-01-01

    Reliability methodology needs to evolve as validity has done into an argument supported by theory and empirical evidence. Nowhere is the inadequacy of current methods more visible than in classroom assessment. Reliability arguments would also permit additional methodologies for evidencing reliability in classrooms. It would liberalize methodology…

  18. Testing for PV Reliability (Presentation)

    SciTech Connect

    Kurtz, S.; Bansal, S.

    2014-09-01

    The DOE SUNSHOT workshop is seeking input from the community about PV reliability and how the DOE might address gaps in understanding. This presentation describes the types of testing that are needed for PV reliability and introduces a discussion to identify gaps in our understanding of PV reliability testing.

  19. Business of reliability

    NASA Astrophysics Data System (ADS)

    Engel, Pierre

    1999-12-01

    The presentation is organized around three themes: (1) The decrease of reception equipment costs allows non-Remote Sensing organization to access a technology until recently reserved to scientific elite. What this means is the rise of 'operational' executive agencies considering space-based technology and operations as a viable input to their daily tasks. This is possible thanks to totally dedicated ground receiving entities focusing on one application for themselves, rather than serving a vast community of users. (2) The multiplication of earth observation platforms will form the base for reliable technical and financial solutions. One obstacle to the growth of the earth observation industry is the variety of policies (commercial versus non-commercial) ruling the distribution of the data and value-added products. In particular, the high volume of data sales required for the return on investment does conflict with traditional low-volume data use for most applications. Constant access to data sources supposes monitoring needs as well as technical proficiency. (3) Large volume use of data coupled with low- cost equipment costs is only possible when the technology has proven reliable, in terms of application results, financial risks and data supply. Each of these factors is reviewed. The expectation is that international cooperation between agencies and private ventures will pave the way for future business models. As an illustration, the presentation proposes to use some recent non-traditional monitoring applications, that may lead to significant use of earth observation data, value added products and services: flood monitoring, ship detection, marine oil pollution deterrent systems and rice acreage monitoring.

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

    SciTech Connect

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

    2012-09-14

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

  1. The Evaluation of a Squid-Based Non-Contact Magnetic Nde Technique for Application to the Inspection of Offshore Steel Structures

    NASA Astrophysics Data System (ADS)

    Evanson, S.

    1988-12-01

    Available from UMI in association with The British Library. Requires signed TDF. Conventional methods of Non Destructive Evaluation (NDE) for the detection of surface-breaking defects in steel structures require intimate contact with the test site. This is a serious limitation in offshore inspection where the structure may be covered with tenacious marine contamination up to 0.5m thick. A method of magnetic examination to detect surface-breaking defects at distances, from a steel specimen, in excess of 10cm is reported. A persistent mode superconducting solenoid generates a DC magnetic field perpendicular to the specimen surface. The spatial distortion of this field by surface defects is detected using a SQUID coupled to a novel planar gradiometer, coaxial with the solenoid. DC operation means detection is unaffected by electrically conductive surface coatings. A point defect is represented by an equivalent magnetic dipole and a long defect by a line dipole with a uniformly distributed magnetic moment. Mathematical models for the response of a gradiometer to magnetic dipole sources are used to design a suitable planar gradiometer. Theoretical and experimental data demonstrate the superior performance of this design compared with a conventional second order gradiometer of the type available commercially. The construction of a system for acquisition and computer processing of data from the examination of steel specimens is discussed. Extensive tests were conducted on flat steel plates containing ideal surface defects and good agreement is found with the defect models. The major limitation on defect resolution is a background field associated with the magnetised steel plate. Background components of low spatial frequency are reduced by balancing the gradiometer, further improvement in resolution is achieved by applying band pass digital filters to the SQUID output. A SQUID system offers considerable promise for remote detection of surface defects in plane steel

  2. Conceptualizing Essay Tests' Reliability and Validity: From Research to Theory

    ERIC Educational Resources Information Center

    Badjadi, Nour El Imane

    2013-01-01

    The current paper on writing assessment surveys the literature on the reliability and validity of essay tests. The paper aims to examine the two concepts in relationship with essay testing as well as to provide a snapshot of the current understandings of the reliability and validity of essay tests as drawn in recent research studies. Bearing in…

  3. Reliability of the Revised Psychopathy Checklist in Substance Abuse Patients.

    ERIC Educational Resources Information Center

    Alterman, Arthur I.; And Others

    1993-01-01

    One month test-retest reliability of the Revised Psychopathy Checklist (PCL-R) was examined in 88 methadone-maintained males, along with effects of increased information about patients on PCL-R scores and diagnostic derivations. Test-retest reliabilities are quite good. Other findings also confirm potential utility of the PCL-R for research. (SLD)

  4. Real time acousto-ultrasonic NDE technique for monitoring damage in ceramic composites under dynamic loads

    NASA Technical Reports Server (NTRS)

    Tiwari, Anil

    1995-01-01

    Research effort was directed towards developing a near real-time, acousto-ultrasonic (AU), nondestructive evaluation (NDE) tool to study the failure mechanisms of ceramic composites. Progression of damage is monitored in real-time by observing the changes in the received AU signal during the actual test. During the real-time AU test, the AU signals are generated and received by the AU transducers attached to the specimen while it is being subjected to increasing quasi-static loads or cyclic loads (10 Hz, R = 1.0). The received AU signals for 64 successive pulses were gated in the time domain (T = 40.96 micro sec) and then averaged every second over ten load cycles and stored in a computer file during fatigue tests. These averaged gated signals are representative of the damage state of the specimen at that point of its fatigue life. This is also the first major attempt in the development and application of real-time AU for continuously monitoring damage accumulation during fatigue without interrupting the test. The present work has verified the capability of the AU technique to assess the damage state in silicon carbide/calcium aluminosilicate (SiC/CAS) and silicon carbide/ magnesium aluminosilicate (SiC/MAS) ceramic composites. Continuous monitoring of damage initiation and progression under quasi-static ramp loading in tension to failure of unidirectional and cross-ply SiC/CAS and quasi-isotropic SiC/MAS ceramic composite specimens at room temperature was accomplished using near real-time AU parameters. The AU technique was shown to be able to detect the stress levels for the onset and saturation of matrix cracks, respectively. The critical cracking stress level is used as a design stress for brittle matrix composites operating at elevated temperatures. The AU technique has found that the critical cracking stress level is 10-15% below the level presently obtained for design purposes from analytical models. An acousto-ultrasonic stress-strain response (AUSSR) model

  5. Review of the Motivated Strategies for Learning Questionnaire (MSLQ) Using Reliability Generalization Techniques to Assess Scale Reliability

    ERIC Educational Resources Information Center

    Taylor, Robin Terrell

    2012-01-01

    Reliability generalization studies were conducted on the motivation and learning strategies scales of the Motivated Strategies for Learning Questionnaire (MSLQ) to typify score reliabilities for all scales on the instrument and to examine potential sources of measurement error across studies which used these scales. Average reliability…

  6. Interrater Reliability in Large-Scale Assessments--Can Teachers Score National Tests Reliably without External Controls?

    ERIC Educational Resources Information Center

    Pantzare, Anna Lind

    2015-01-01

    In most large-scale assessment systems a set of rather expensive external quality controls are implemented in order to guarantee the quality of interrater reliability. This study empirically examines if teachers' ratings of national tests in mathematics can be reliable without using monitoring, training, or other methods of external quality…

  7. The Estimation of the IRT Reliability Coefficient and Its Lower and Upper Bounds, with Comparisons to CTT Reliability Statistics

    ERIC Educational Resources Information Center

    Kim, Seonghoon; Feldt, Leonard S.

    2010-01-01

    The primary purpose of this study is to investigate the mathematical characteristics of the test reliability coefficient rho[subscript XX'] as a function of item response theory (IRT) parameters and present the lower and upper bounds of the coefficient. Another purpose is to examine relative performances of the IRT reliability statistics and two…

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  9. Computational methods for efficient structural reliability and reliability sensitivity analysis

    NASA Technical Reports Server (NTRS)

    Wu, Y.-T.

    1993-01-01

    This paper presents recent developments in efficient structural reliability analysis methods. The paper proposes an efficient, adaptive importance sampling (AIS) method that can be used to compute reliability and reliability sensitivities. The AIS approach uses a sampling density that is proportional to the joint PDF of the random variables. Starting from an initial approximate failure domain, sampling proceeds adaptively and incrementally with the goal of reaching a sampling domain that is slightly greater than the failure domain to minimize over-sampling in the safe region. Several reliability sensitivity coefficients are proposed that can be computed directly and easily from the above AIS-based failure points. These probability sensitivities can be used for identifying key random variables and for adjusting design to achieve reliability-based objectives. The proposed AIS methodology is demonstrated using a turbine blade reliability analysis problem.

  10. Early detection of critical material degradation by means of electromagnetic multi-parametric NDE

    SciTech Connect

    Szielasko, Klaus; Tschuncky, Ralf; Rabung, Madalina; Altpeter, Iris; Dobmann, Gerd; Seiler, Georg; Herrmann, Hans-Georg; Boller, Christian

    2014-02-18

    With an increasing number of power plants operated in excess of their original design service life an early recognition of critical material degradation in components will gain importance. Many years of reactor safety research allowed for the identification and development of electromagnetic NDE methods which detect precursors of imminent damage with high sensitivity, at elevated temperatures and in a radiation environment. Regarding low-alloy heat-resistant steel grade WB 36 (1.6368, 15NiCuMoNb5), effects of thermal and thermo-mechanical aging on mechanical-technological properties and several micromagnetic parameters have been thoroughly studied. In particular knowledge regarding the process of copper precipitation and its acceleration under thermo-mechanical load has been enhanced. Whilst the Cu-rich WB 36 steel is an excellent model material to study and understand aging effects related to neutron radiation without the challenge of handling radioactive specimens in a hot cell, actually neutron-irradiated reactor pressure vessel materials were investigated as well. The neutron fluence experienced and the resulting shift of the ductile-brittle transition temperature were determined electromagnetically, and it was shown that weld and base material can be distinguished from the cladded side of the RPV wall. Low-cycle fatigue of the austenitic stainless steel AISI 347 (1.4550, X6CrNiNb18-10) has been characterized with electromagnetic acoustic transducers (EMATs) at temperatures of up to 300 °C. Time-of-flight and amplitude of the transmitted ultrasound signal were evaluated against the number of load cycles applied and observed as an indication of the imminent material failure significantly earlier than monitoring stresses or strains.

  11. The effect of variation in phased array element performance for Non-Destructive Evaluation (NDE).

    PubMed

    Duxbury, David; Russell, Jonathan; Lowe, Michael

    2013-08-01

    This paper reports the results of an investigation into the effects of phased array element performance on ultrasonic beam integrity. This investigation has been performed using an array beam model based on Huygens' principle to independently investigate the effects of element sensitivity and phase, and non-functioning elements via Monte Carlo simulation. The purpose of this work is to allow a new method of array calibration for Non-Destructive Evaluation (NDE) to be adopted that focuses on probe integrity rather than beam integrity. This approach is better suited to component inspections that utilise Full Matrix Capture (FMC) to record data as the calibration routine is uncoupled from the beams that the array is required to produce. For this approach to be adopted specifications must be placed on element performance that guarantee beam quality without carrying out any beam forming. The principal result of this investigation is that the dominant outcome following variations in array element performance is the introduction of beam artefacts such as main beam broadening, raising of the noise floor of the ultrasonic field, and the enlargement or creation of side lobes. Specifications for practical allowable limits of element sensitivity, element phase, and the number of non-functioning elements have been suggested based on a minimum amplitude difference between beam artefacts and the main beam peak of 8 dB. Simulation at a number of centre frequencies has led to a recommendation that the product of transducer bandwidth and maximum phase error should be kept below 0.051 and 0.035 for focused and plane beams respectively. Element sensitivity should be within 50% of mean value of the aperture, and no more than 9% of the elements should be non-functioning. PMID:23337826

  12. Early detection of critical material degradation by means of electromagnetic multi-parametric NDE

    NASA Astrophysics Data System (ADS)

    Szielasko, Klaus; Tschuncky, Ralf; Rabung, Madalina; Seiler, Georg; Altpeter, Iris; Dobmann, Gerd; Herrmann, Hans-Georg; Boller, Christian

    2014-02-01

    With an increasing number of power plants operated in excess of their original design service life an early recognition of critical material degradation in components will gain importance. Many years of reactor safety research allowed for the identification and development of electromagnetic NDE methods which detect precursors of imminent damage with high sensitivity, at elevated temperatures and in a radiation environment. Regarding low-alloy heat-resistant steel grade WB 36 (1.6368, 15NiCuMoNb5), effects of thermal and thermo-mechanical aging on mechanical-technological properties and several micromagnetic parameters have been thoroughly studied. In particular knowledge regarding the process of copper precipitation and its acceleration under thermo-mechanical load has been enhanced. Whilst the Cu-rich WB 36 steel is an excellent model material to study and understand aging effects related to neutron radiation without the challenge of handling radioactive specimens in a hot cell, actually neutron-irradiated reactor pressure vessel materials were investigated as well. The neutron fluence experienced and the resulting shift of the ductile-brittle transition temperature were determined electromagnetically, and it was shown that weld and base material can be distinguished from the cladded side of the RPV wall. Low-cycle fatigue of the austenitic stainless steel AISI 347 (1.4550, X6CrNiNb18-10) has been characterized with electromagnetic acoustic transducers (EMATs) at temperatures of up to 300 °C. Time-of-flight and amplitude of the transmitted ultrasound signal were evaluated against the number of load cycles applied and observed as an indication of the imminent material failure significantly earlier than monitoring stresses or strains.

  13. A combined NDE/FEA approach to evaluate the structural response of a metal foam

    NASA Astrophysics Data System (ADS)

    Ghosn, Louis J.; Abdul-Aziz, Ali; Raj, Sai V.; Rauser, Richard W.

    2007-04-01

    Metal foams are expected to find use in structural applications where weight is of particular concern, such as space vehicles, rotorcraft blades, car bodies or portable electronic devices. The obvious structural application of metal foam is for light weight sandwich panels, made up of thin solid face sheets and a metallic foam core. The stiffness of the sandwich structure is increased by separating the two face sheets by a light weight metal foam core. The resulting high-stiffness structure is lighter than that constructed only out of the solid metal material. Since the face sheets carry the applied in-plane and bending loads, the sandwich architecture is a viable engineering concept. However, the metal foam core must resist transverse shear loads and compressive loads while remaining integral with the face sheets. Challenges relating to the fabrication and testing of these metal foam panels remain due to some mechanical properties falling short of their theoretical potential. Theoretical mechanical properties are based on an idealized foam microstructure and assumed cell geometry. But the actual testing is performed on as fabricated foam microstructure. Hence in this study, a detailed three dimensional foam structure is generated using series of 2D Computer Tomography (CT) scans. The series of the 2D images are assembled to construct a high precision solid model capturing all the fine details within the metal foam as detected by the CT scanning technique. Moreover, a finite element analysis is then performed on as fabricated metal foam microstructures, to calculate the foam mechanical properties with the idealized theory. The metal foam material is an aerospace grade precipitation hardened 17-4 PH stainless steel with high strength and high toughness. Tensile and compressive mechanical properties are deduced from the FEA model and compared with the theoretical values for three different foam densities. The combined NDE/FEA provided insight in the variability of

  14. Evaluation of different scintillators for 1MV NDE x-ray imaging

    NASA Astrophysics Data System (ADS)

    Zentai, George; Ganguly, Arundhuti; Visrshup, Gary

    2014-03-01

    X-ray radiography is an important and frequently used NDE method of testing metal structures, such as tube welding quality, cracks and voids in cast iron or other metals. It gives fast and visible answer for structural defects. The Varian high energy portal imagers on Clinacs used in cancer treatment were tested for this purpose. We compared the traditional Gadox (LANEX) screen with and without a 1mm Cu buildup plate as used clinically. We also tested different hybrid scintillators, which consisted of different phosphor layers deposited onto fiberoptic plates. The last screen tested was a 2cm thick fiberoptic plate which contained scintillating fibers. The sensitivity (ADU = number of digital counts per a given X-ray dose), the resolution (MTF - modulation transfer function) and the DQE (detective quantum efficiency) were compared, with a 1 MV source, for these X-ray conversion screens. We found that the additional 1mm Cu plate, which improves the absorption and the contrast at 6 or higher energy MeV imaging, does not improve the image quality at 1MV. Rather it attenuates the X-rays, resulting in lower sensitivity and a lower DQE(0) of 2.2% with the additional Cu plate compared to DQE(0) of ~4% without the Cu plate. The hybrid scintillators with evaporated phosphors on fiberoptic plates tested were too thin resulting in low sensitivity. The best results were obtained from the thick scintillating fiberoptic screens, which provided the best DQE and high resolution with the 1MV X-ray beam. Further optimization is planned by changing the thickness of the scintillating fiber optic plate.

  15. Silicon Nitride Plates for Turbine Blade Application: FEA and NDE Assessment

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    Engine manufacturers are continually attempting to improve the performance and the overall efficiency of internal combustion engines. The thermal efficiency is typically improved by raising the operating temperature of essential engine components in the combustion area. This reduces the heat loss to a cooling system and allows a greater portion of the heat to be used for propulsion. Further improvements can be achieved by diverting part of the air from the compressor, which would have been used in the combustor for combustion purposes, into the turbine components. Such a process is called active cooling. Increasing the operating temperature, decreasing the cooling air, or both can improve the efficiency of the engine. Furthermore, lightweight, strong, tough hightemperature materials are required to complement efficiency improvement for nextgeneration gas turbine engines that can operate with minimum cooling. Because of their low-density, high-temperature strength, and thermal conductivity, ceramics are being investigated as potential materials for replacing ordinary metals that are currently used for engine hot section components. Ceramic structures can withstand higher operating temperatures and other harsh environmental factors. In addition, their low densities relative to metals helps condense component mass (ref. 1). The objectives of this program at the NASA Glenn Research Center are to develop manufacturing technology, a thermal barrier coating/environmental barrier coating (TBC/EBC), and an analytical modeling capability to predict thermomechanical stresses, and to do minimal burner rig tests of silicon nitride (Si3N4) and SiC/SiC turbine nozzle vanes under simulated engine conditions. Furthermore, and in support of the latter objectives, an optimization exercise using finite element analysis and nondestructive evaluation (NDE) was carried out to characterize and evaluate silicon nitride plates with cooling channels.

  16. Wireless Self-powered Visual and NDE Robotic Inspection System for Live Gas Distribution Mains

    SciTech Connect

    Susan Burkett; Hagen Schempf

    2006-01-31

    Carnegie Mellon University (CMU) under contract from Department of Energy/National Energy Technology Laboratory (DoE/NETL) and co-funding from the Northeast Gas Association (NGA), has completed the overall system design of the next-generation Explorer-II (X-II) live gas main NDE and visual inspection robot platform. The design is based on the Explorer-I prototype which was built and field-tested under a prior (also DoE- and NGA co-funded) program, and served as the validation that self-powered robots under wireless control could access and navigate live natural gas distribution mains. The X-II system design ({approx}8 ft. and 66 lbs.) was heavily based on the X-I design, yet was substantially expanded to allow the addition of NDE sensor systems (while retaining its visual inspection capability), making it a modular system, and expanding its ability to operate at pressures up to 750 psig (high-pressure and unpiggable steel-pipe distribution mains). A new electronics architecture and on-board software kernel were added to again improve system performance. A locating sonde system was integrated to allow for absolute position-referencing during inspection (coupled with external differential GPS) and emergency-locating. The power system was upgraded to utilize lithium-based battery-cells for an increase in mission-time. The system architecture now relies on a dual set of end camera-modules to house the 32-bit processors (Single-Board Computer or SBC) as well as the imaging and wireless (off-board) and CAN-based (on-board) communication hardware and software systems (as well as the sonde-coil and -electronics). The drive-module (2 ea.) are still responsible for bracing (and centering) to drive in push/pull fashion the robot train into and through the pipes and obstacles. The steering modules and their arrangement, still allow the robot to configure itself to perform any-angle (up to 90 deg) turns in any orientation (incl. vertical), and enable the live launching and

  17. A model for managing the cost of reliability

    NASA Astrophysics Data System (ADS)

    Sears, Raymond W., Jr.

    A parametric model which estimates the distribution of effort expended in the achievement of reliability during the various phases of product development has been formulated, with a view to the maximization of return on reliability investment. The model equations and their associated minimization criteria have been programmed on a PC to allow the examination of the effects of varying parameters on the development process and the reliability-achievement strategy, as well as to allow the calibration of modeling parameters against cost and reliability data obtained by various development programs. Model calibration accommodates numerous plausible scenarios of product development.

  18. Reliability of wireless sensor networks.

    PubMed

    Dâmaso, Antônio; Rosa, Nelson; Maciel, Paulo

    2014-01-01

    Wireless Sensor Networks (WSNs) consist of hundreds or thousands of sensor nodes with limited processing, storage, and battery capabilities. There are several strategies to reduce the power consumption of WSN nodes (by increasing the network lifetime) and increase the reliability of the network (by improving the WSN Quality of Service). However, there is an inherent conflict between power consumption and reliability: an increase in reliability usually leads to an increase in power consumption. For example, routing algorithms can send the same packet though different paths (multipath strategy), which it is important for reliability, but they significantly increase the WSN power consumption. In this context, this paper proposes a model for evaluating the reliability of WSNs considering the battery level as a key factor. Moreover, this model is based on routing algorithms used by WSNs. In order to evaluate the proposed models, three scenarios were considered to show the impact of the power consumption on the reliability of WSNs. PMID:25157553

  19. Nuclear weapon reliability evaluation methodology

    SciTech Connect

    Wright, D.L.

    1993-06-01

    This document provides an overview of those activities that are normally performed by Sandia National Laboratories to provide nuclear weapon reliability evaluations for the Department of Energy. These reliability evaluations are first provided as a prediction of the attainable stockpile reliability of a proposed weapon design. Stockpile reliability assessments are provided for each weapon type as the weapon is fielded and are continuously updated throughout the weapon stockpile life. The reliability predictions and assessments depend heavily on data from both laboratory simulation and actual flight tests. An important part of the methodology are the opportunities for review that occur throughout the entire process that assure a consistent approach and appropriate use of the data for reliability evaluation purposes.

  20. Primary Water Stress Corrosion Cracks in Nickel Alloy Dissimilar Metal Welds: Detection and Sizing Using Established and Emerging Nondestructive Examination Techniques

    SciTech Connect

    Braatz, Brett G.; Cumblidge, Stephen E.; Doctor, Steven R.; Prokofiev, Iouri

    2012-12-31

    The U.S. Nuclear Regulatory Commission has established the Program to Assess the Reliability of Emerging Nondestructive Techniques (PARENT) as a follow-on to the international cooperative Program for the Inspection of Nickel Alloy Components (PINC). The goal of PINC was to evaluate the capabilities of various nondestructive evaluation (NDE) techniques to detect and characterize surface-breaking primary water stress corrosion cracks in dissimilar-metal welds (DMW) in bottom-mounted instrumentation (BMI) penetrations and small-bore (≈400-mm diameter) piping components. A series of international blind round-robin tests were conducted by commercial and university inspection teams. Results from these tests showed that a combination of conventional and phased-array ultrasound techniques provided the highest performance for flaw detection and depth sizing in dissimilar metal piping welds. The effective detection of flaws in BMIs by eddy current and ultrasound shows that it may be possible to reliably inspect these components in the field. The goal of PARENT is to continue the work begun in PINC and apply the lessons learned to a series of open and blind international round-robin tests that will be conducted on a new set of piping components including large-bore (≈900-mm diameter) DMWs, small-bore DMWs, and BMIs. Open round-robin testing will engage universities and industry worldwide to investigate the reliability of emerging NDE techniques to detect and accurately size flaws having a wide range of lengths, depths, orientations, and locations. Blind round-robin testing will invite testing organizations worldwide, whose inspectors and procedures are certified by the standards for the nuclear industry in their respective countries, to investigate the ability of established NDE techniques to detect and size flaws whose characteristics range from easy to very difficult to detect and size. This paper presents highlights of PINC and reports on the plans and progress for