Flaw identification using acoustic emission

International Nuclear Information System (INIS)

Woodward, B.; McDonald, N.R.

1975-01-01

Acoustic emission 'signatures' contain information about the fine structure of metallurgical source events and their interpretation may provide a means of assessing the severity of internal flaws as well as surface flaws. The ultimate aim of this research on signature analysis is to develop a real time non-destructive testing technique having the capability of flaw recognition as well as flaw location in nuclear reactor components and structures under stress. Thus the requisite, unlike that in most acoustic emission work to date, is for a technique which affords discrimination between acoustic emission from different types of flaws propagating simultaneously. The approach described here requires detailed analysis of the emission signatures in terms of a specific statistical parameter, energy spectral density. In order to realise the full inspection potential of acoustic emission monitoring data obtained from zirconium and steel testpieces have been correlated with metallurgical condition and mechanical behaviour, since the nature of emission signatures is strongly affected by the physical characteristics and internal structure of the material. (Auth.)

High-temperature flaw assessment procedure: A state-of-the-art survey

International Nuclear Information System (INIS)

Ruggles, M.B.; Takahashi, Y.

1989-05-01

High-temperature crack growth under cyclic, static, and combined loading is received with an emphasis on fracture mechanics aspects. Experimental studies of the effects of loading history, microstructure, temperature, and environment on crack growth behavior are described and interpreted. The experimental evidence is used to examine crack growth parameters and theoretical models for fatigue, creep, and creep-fatigue crack propagation at elevated temperatures. The limitations of both elastic and elastic-plastic fracture mechanics for high-temperature subcritical crack growth are assessed. Existing techniques for modeling critical crack growth/ligament instability failure are also presented. Related topics of defect modeling and engineering flaw assessment procedures, nondestructive evaluation methods, and probabilistic failure analysis are briefly discussed. 142 refs., 33 figs

Flaw distribution development from vessel ISI data

International Nuclear Information System (INIS)

Foulds, J.R.; Kennedy, E.L.; Basin, S.L.; Rosinski, S.T.

1991-01-01

Previous attempts to develop flaw distributions for use in the structural integrity evaluation of pressurized water reactor (PWR) vessels have aimed at the estimation of a ''generic'' distribution applicable to all vessels. In contrast, this paper describes the analysis of vessel-specific in-service inspection (ISI) data for the development of a flaw distribution reliably representative of the condition of the particular vessel inspected. The application of the methodology may be extended to other vessels, but has been primarily developed for PWR reactor vessels. For this study, the flaw data analyzed included data obtained from three recently performed PWR vessel ISIs and from laboratory inspection of selected weldment sections of the Midland reactor vessel. The variability in both the character of the reviewed data (size range of flaws, number of flaws) and the UT (ultrasonic test) inspection system performance identified a need for analyzing the inspection results on a vessel-, or data set-specific basis. For this purpose, traditional histogram-based methods were inadequate, and a new methodology that can accept a very small number of flaws (typical of vessel-specific ISI results) and that includes consideration of inspection system flaw detection reliability, flaw sizing accuracy and flaw detection threshold, was developed. Results of the application of the methodology to each of the four PWR reactor vessel cases studied are presented and discussed

Eddy Current Flaw Characterization Using Neural Networks

International Nuclear Information System (INIS)

Song, S. J.; Park, H. J.; Shin, Y. K.

1998-01-01

Determination of location, shape and size of a flaw from its eddy current testing signal is one of the fundamental issues in eddy current nondestructive evaluation of steam generator tubes. Here, we propose an approach to this problem; an inversion of eddy current flaw signal using neural networks trained by finite element model-based synthetic signatures. Total 216 eddy current signals from four different types of axisymmetric flaws in tubes are generated by finite element models of which the accuracy is experimentally validated. From each simulated signature, total 24 eddy current features are extracted and among them 13 features are finally selected for flaw characterization. Based on these features, probabilistic neural networks discriminate flaws into four different types according to the location and the shape, and successively back propagation neural networks determine the size parameters of the discriminated flaw

PWR vessel flaw distribution development

International Nuclear Information System (INIS)

Rosinski, S.T.; Kennedy, E.L.; Foulds, J.R.; Kinsman, K.M.

1990-01-01

This paper reports on PWR pressure vessels which operate under NRC rules and regulatory guides intended to prevent failure of the vessels. Plants failing to meet the operating criteria specified under these rules and regulations are required to analytically demonstrate fitness for service in order to continue operation. The initial flaw size or distribution of initial vessel flaws is a key input to the required vessel integrity analyses. However, the flaw distribution assumed in the development of the NRC Regulations and recommended for the plant specific analyses is potentially over-conservative. This is because the distribution is based on the limited amount of vessel inspection data available at the time the criteria were being developed and does not take full advantage of the more recent and reliable domestic vessel inspection results. The U.S. Department of Energy is funding an effort through Sandia National Laboratories to investigate the possibility of developing a new flaw distribution based on the increased amount and improved reliability of domestic vessel inspection data. Results of Phase I of the program indicate that state-of-the-art NDE systems' capabilities are sufficient for development of a new flaw distribution that could ultimately provide life extension benefits over the presently required operating practice

Ultrasonic flaw detection in a monorail box beam

Science.gov (United States)

Zheng, Peng; Greve, David W.; Oppenheim, Irving J.

2009-03-01

A steel box beam in a monorail application is constructed with an epoxy grout wearing surface, precluding visual inspection of its top flange. This paper describes a sequence of experimental research tasks to develop an ultrasonic system to detect flaws (such as fatigue cracks) in that flange, and the results of a field test to demonstrate system performance. The problem is constrained by the fact that the flange is exposed only along its longitudinal edges, and by the fact that permanent installation of transducers at close spacing was deemed to be impractical. The system chosen for development, after experimental comparison of alternate technologies, features angle-beam ultrasonic transducers with fluid coupling to the flange edge; the emitting transducers create transverse waves that travel diagonally across the width of the flange, where an array of receiving transducers detect flaw reflections and flaw shadows. The system rolls along the box beam, surveying (screening) the top flange for the presence of flaws. In a first research task, conducted on a full-size beam specimen, we compared waves generated from different transducer locations, either the flange edge or the web face, and at different frequency ranges. At relatively low frequencies, such as 100 kHz, we observed Lamb wave modes, and at higher frequency, in the MHz range, we observed nearlylongitudinal waves with trailing pulses. In all cases we observed little attenuation by the wearing surface and little influence of reflection at the web-flange joints. At the conclusion of this task we made the design decision to use edgemounted transducers at relatively high frequency, with correspondingly short wavelength, for best scattering from flaws. In a second research task we conducted experiments at 55% scale on a steel plate, with machined flaws of different size, and detected flaws of target size for the intended application. We then compared the performance of bonded transducers, fluid

Flaw assessment procedure for high temperature reactor components

International Nuclear Information System (INIS)

Ainsworth, R.A.; Takahashi, Y.

1990-01-01

An interim high-temperature flaw assessment procedure is described. This is a result of a collaborative effort between Electric Power Research Institute in the USA, Central Research Institute of Electric Power Industry in Japan, and Nuclear Electric plc in the UK. The procedure addresses preexisting defects subject to creep-fatigue loading conditions. Laws employed to calculate the crack growth per cycle are defined in terms of fracture mechanics parameters and constants related to the component material. The crack growth laws may be integrated to calculate the remaining life of a component or to predict the amount of crack extension in a given period. Fatigue and creep crack growth per cycle are calculated separately, and the total crack extension is taken as the simple sum of the two contributions. An interaction between the two propagation modes is accounted for in the material properties in the separate calculations. In producing the procedure, limitations of the approach have been identified. Some of these limitations are to be addressed in an extension of the current collaborative program. 20 refs

Flaws in Commercial Reading Materials.

Science.gov (United States)

Axelrod, Jerome

Three flaws found in commercial reading materials, such as workbooks and kits, are discussed in this paper, and examples of the flaws are taken from specific materials. The first problem noted is that illustrations frequently provide the information that the learner is supposed to supply through phonetic or structural analysis; the illustrations…

Fabrication Flaw Density and Distribution in Weld Repairs

International Nuclear Information System (INIS)

Doctor, Steven R.

2009-01-01

The Pacific Northwest National Laboratory (PNNL) is developing a generalized flaw distribution for the population of nuclear reactor pressure vessels and for piping welds in the U. S. operating reactors. The purpose of the generalized flaw distribution is to predict component-specific flaw densities. The estimates of fabrication flaws are intended for use in fracture mechanics structural integrity assessments. Structural integrity assessments, such as estimating the frequency of loss-of-coolant accidents, are performed by computer codes that require, as input, accurate estimates of flaw densities. Welds from four different cancelled reactor pressure vessels and a collection of archived pipes have been studied to develop empirical estimates of fabrication flaw densities. This paper describes the fabrication flaw distribution and characterization in the repair weld metal of vessels and piping. This work indicates that large flaws occur in these repairs which are complex in composition and sometimes include cracks on the ends of the repair cavities. Parametric analysis using an exponential fit is performed on the data. Construction records where available were reviewed. It is difficult to make conclusions due to the limited number of construction records reviewed. However, the records reviewed to date show a significant change in repair frequency over the years when the components in this study were fabricated. A description of repair flaw morphology is provided with a discussion of fracture mechanics significance.

Probabilistic analysis of flaw distribution on structure under cyclic load

International Nuclear Information System (INIS)

Kwak, Sang Log; Choi, Young Hwan; Kim, Hho Jung

2003-01-01

Flaw geometries, applied stress, and material properties are major input variables for the fracture mechanics analysis. Probabilistic approach can be applied for the consideration of uncertainties within these input variables. But probabilistic analysis requires many assumptions due to the lack of initial flaw distributions data. In this study correlations are examined between initial flaw distributions and in-service flaw distributions on structures under cyclic load. For the analysis, LEFM theories and Monte Carlo simulation are applied. Result shows that in-service flaw distributions are determined by initial flaw distributions rather than fatigue crack growth rate. So initial flaw distribution can be derived from in-service flaw distributions

Evaluation of flaws in carbon steel piping. Final report

Energy Technology Data Exchange (ETDEWEB)

Zahoor, A.; Gamble, R.M.; Mehta, H.S.; Yukawa, S.; Ranganath, S.

1986-10-01

The objective of this program was to develop flaw evaluation procedures and allowable flaw sizes for ferritic piping used in light water reactor (LWR) power generation facilities. The program results provide relevant ASME Code groups with the information necessary to define flaw evaluation procedures, allowable flaw sizes, and their associated bases for Section XI of the code. Because there are several possible flaw-related failure modes for ferritic piping over the LWR operating temperature range, three analysis methods were employed to develop the evaluation procedures. These include limit load analysis for plastic collapse, elastic plastic fracture mechanics (EPFM) analysis for ductile tearing, and linear elastic fracture mechanics (LEFM) analysis for non ductile crack extension. To ensure the appropriate analysis method is used in an evaluation, a step by step procedure also is provided to identify the relevant acceptance standard or procedure on a case by case basis. The tensile strength and toughness properties required to complete the flaw evaluation for any of the three analysis methods are included in the evaluation procedure. The flaw evaluation standards are provided in tabular form for the plastic collapse and ductile tearing modes, where the allowable part through flaw depth is defined as a function of load and flaw length. For non ductile crack extension, linear elastic fracture mechanics analysis methods, similar to those in Appendix A of Section XI, are defined. Evaluation flaw sizes and procedures are developed for both longitudinal and circumferential flaw orientations and normal/upset and emergency/faulted operating conditions. The tables are based on margins on load of 2.77 and 1.39 for circumferential flaws and 3.0 and 1.5 for longitudinal flaws for normal/upset and emergency/faulted conditions, respectively.

Evaluation of flaws in carbon steel piping. Final report

International Nuclear Information System (INIS)

Zahoor, A.; Gamble, R.M.; Mehta, H.S.; Yukawa, S.; Ranganath, S.

1986-10-01

The objective of this program was to develop flaw evaluation procedures and allowable flaw sizes for ferritic piping used in light water reactor (LWR) power generation facilities. The program results provide relevant ASME Code groups with the information necessary to define flaw evaluation procedures, allowable flaw sizes, and their associated bases for Section XI of the code. Because there are several possible flaw-related failure modes for ferritic piping over the LWR operating temperature range, three analysis methods were employed to develop the evaluation procedures. These include limit load analysis for plastic collapse, elastic plastic fracture mechanics (EPFM) analysis for ductile tearing, and linear elastic fracture mechanics (LEFM) analysis for non ductile crack extension. To ensure the appropriate analysis method is used in an evaluation, a step by step procedure also is provided to identify the relevant acceptance standard or procedure on a case by case basis. The tensile strength and toughness properties required to complete the flaw evaluation for any of the three analysis methods are included in the evaluation procedure. The flaw evaluation standards are provided in tabular form for the plastic collapse and ductile tearing modes, where the allowable part through flaw depth is defined as a function of load and flaw length. For non ductile crack extension, linear elastic fracture mechanics analysis methods, similar to those in Appendix A of Section XI, are defined. Evaluation flaw sizes and procedures are developed for both longitudinal and circumferential flaw orientations and normal/upset and emergency/faulted operating conditions. The tables are based on margins on load of 2.77 and 1.39 for circumferential flaws and 3.0 and 1.5 for longitudinal flaws for normal/upset and emergency/faulted conditions, respectively

Supersonic flaw detection device for nozzle

International Nuclear Information System (INIS)

Hata, Moriki.

1996-01-01

In a supersonic flaw detection device to be attached to a body surface of a reactor pressure vessel for automatically detecting flaws of a welded portion of a horizontally connected nozzle by using supersonic waves, a running vehicle automatically running along a circumferential direction of the nozzle comprises a supersonic flaw detection means for detecting flaws of the welded portion of the nozzle by using supersonic waves, and an inclination angle sensor for detecting the inclination angle of the running vehicle relative to the central axis of the nozzle. The running distance of the vehicle running along the circumference of the nozzle, namely, the position of the running vehicle from a reference point of the nozzle can be detected accurately by dividing the distance around the nozzle by the inclination angle detected by the inclination angle sensor. Accordingly, disadvantages in the prior art, for example, that the detected values obtained by using an encoder are changed by slipping or idle running of the magnet wheels are eliminated, and accurate flaw detection can be conducted. In addition, an operation of visually adjusting the reference point for the device can be eliminated. An operator's exposure dose can be reduced. (N.H.)

Labor security in radiation flaw detection

International Nuclear Information System (INIS)

Margulis, U.Ya.; Chistov, E.D.; Partolin, O.F.; Pertsov, V.A.; Momzhiev, B.N.; Sprygaev, I.F.

1986-01-01

Problems of ensuring safe labour conditions in radiation flaw detection are considered. Methods for ionizing radiation protection are given calculating techniques for shielding flaw detectors and stationary structures are presented as well. Safe methods of nondestructive testing of items under field conditions, in a shop and special laboratories using gamma- and X-ray flaw detectors, betatrons, electron accelerators are described. Attention is paid to the principles of radiation factor stantardization as well as radiation monitoring. Analysis of accidents and recommendations on their prevention and liquidation of accidental consequences are given

Nuclear reactor pressure vessel-specific flaw distribution development

International Nuclear Information System (INIS)

Rosinski, S.T.

1992-01-01

Vessel integrity predictions performed through fracture mechanics analysis of a pressurized thermal shock event have been shown to be significantly sensitive to the overall flaw distribution input. It has also been shown that modem vessel in-service inspection (ISI) results can be used for development of vessel flaw distribution(s) that are more representative of US vessels. This paper describes the development and application of a methodology to analyze ISI data for the purpose of flaw distribution determination. The resultant methodology considers detection reliability, flaw sizing accuracy, and flaw detection threshold in its application. Application of the methodology was then demonstrated using four recently acquired US PWR vessel inspection data sets. Throughout the program, new insight was obtained into several key inspection performance and vessel integrity prediction practice issues that will impact future vessel integrity evaluation. For example, the potential application of a vessel-specific flaw distribution now provides at least one method by which a vessel-specific reference flaw size applicable to pressure-temperature limit curves determination can be estimated. This paper will discuss the development and application of the methodology and the impact to future vessel integrity analyses

Midland reactor pressure vessel flaw distribution

International Nuclear Information System (INIS)

Foulds, J.R.; Kennedy, E.L.; Rosinski, S.T.

1993-12-01

The results of laboratory nondestructive examination (NDE), and destructive cross-sectioning of selected weldment sections of the Midland reactor pressure vessel were analyzed per a previously developed methodology in order to develop a flaw distribution. The flaw distributions developed from the NDE results obtained by two different ultrasonic test (UT) inspections (Electric Power Research Institute NDE Center and Pacific Northwest Laboratories) were not statistically significantly different. However, the distribution developed from the NDE Center's (destructive) cross-sectioning-based data was found to be significantly different than those obtained through the UT inspections. A fracture mechanics-based comparison of the flaw distributions showed that the cross-sectioning-based data, conservatively interpreted (all defects considered as flaws), gave a significantly lower vessel failure probability when compared with the failure probability values obtained using the UT-based distributions. Given that the cross-sectioning data were reportedly biased toward larger, more significant-appearing (by UT) indications, it is concluded that the nondestructive examinations produced definitively conservative results. In addition to the Midland vessel inspection-related analyses, a set of twenty-seven numerical simulations, designed to provide a preliminary quantitative assessment of the accuracy of the flaw distribution method used here, were conducted. The calculations showed that, in more than half the cases, the analysis produced reasonably accurate predictions

The influence of finite-length flaw effects on PTS analyses

International Nuclear Information System (INIS)

Keeney-Walker, J.; Dickson, T.L.

1993-01-01

Current licensing issues within the nuclear industry dictate a need to investigate the effects of cladding on the extension of small finite-length cracks near the inside surface of a vessel. Because flaws having depths of the order of the combined clad and heat affected zone thickness dominate the frequency distribution of flaws, their initiation probabilities can govern calculated vessel failure probabilities. Current pressurized-thermal-shock (PTS) analysis computer programs recognize the influence of the inner-surface cladding layer in the heat transfer and stress analysis models, but assume the cladding fracture toughness is the same as that for the base material. The programs do not recognize the influence cladding may have in inhibiting crack initiation and propagation of shallow finite-length surface flaws. Limited experimental data and analyses indicate the cladding can inhibit the propagation of certain shallow flaws. This paper describes an analytical study which was carried out to determine (1) the minimum flaw depth for crack initiation under PTS loading for semicircular surface flaws in a clad reactor pressure vessel and (2) the impact, in terms of the conditional probability of vessel failure, of using a semicircular surface flaw as the initial flaw and assuming that the flaw cannot propagate in the cladding. The analytical results indicate that for initiation a much deeper critical crack depth is required for the finite-length flaw than for the infinite-length flaw, except for the least severe transient. The minimum flaw depths required for crack initiation from the finite-length flaw analyses were incorporated into a modified version of the OCA-P code. The modified code was applied to the analysis of selected PTS transients, and the results produced a substantial decrease in the conditional probability of failure. This initial study indicates a significant effect on probabilistic fracture analyses by incorporating finite-length flaw results

An interim report on shallow-flaw fracture technology development

International Nuclear Information System (INIS)

Pennell, W.E.; Bass, B.R.; Bryson, J.W.; McAfee, W.J.

1995-01-01

Shallow-flaw fracture technology is being developed for application to the safety assessment of radiation-embrittled nuclear reactor pressure vessels (RPVS) containing flaws. Fracture mechanics tests on RPV steel, coupled with detailed elastic-plastic finite-element analyses of the crack-tip stress fields, have shown that (1) constraint relaxation at the crack tip of shallow surface flaws results in increased data scatter but no increase in the lower-bound fracture toughness, (2) the nil ductility temperature (NDT) performs better than the reference temperature for nil ductility transition (RT NDT ) as a normalizing parameter for shallow-flaw fracture toughness data, (3) biaxial loading can reduce the shallow-flaw fracture toughness, (4) stress-based dual-parameter fracture toughness correlations cannot predict the effect of biaxial loading on shallow-flaw fracture toughness because in-plane stresses at the crack tip are not influenced by biaxial loading, and (5) a strain-based dual-parameter fracture toughness correlation can predict the effect of biaxial loading on shallow-flaw fracture toughness

Magnetite Core-Shell Nanoparticles in Nondestructive Flaw Detection of Polymeric Materials.

Science.gov (United States)

Hetti, Mimi; Wei, Qiang; Pohl, Rainer; Casperson, Ralf; Bartusch, Matthias; Neu, Volker; Pospiech, Doris; Voit, Brigitte

2016-10-04

Nondestructive flaw detection in polymeric materials is important but difficult to achieve. In this research, the application of magnetite nanoparticles (MNPs) in nondestructive flaw detection is studied and realized, to the best of our knowledge, for the first time. Superparamagnetic and highly magnetic (up to 63 emu/g) magnetite core-shell nanoparticles are prepared by grafting bromo-end-group-functionalized poly(glycidyl methacrylate) (Br-PGMA) onto surface-modified Fe 3 O 4 NPs. These Fe 3 O 4 -PGMA NPs are blended into bisphenol A diglycidylether (BADGE)-based epoxy to form homogeneously distributed magnetic epoxy nanocomposites (MENCs) after curing. The core Fe 3 O 4 of the Fe 3 O 4 -PGMA NPs endows the MENCs with magnetic property, which is crucial for nondestructive flaw detection of the materials, while the shell PGMA promotes colloidal stability and prevents NP aggregation during curing. The eddy current testing (ET) technique is first applied to detect flaws in the MENCs. Through the brightness contrast of the ET image, surficial and subsurficial flaws in MENCs can be detected, even for MENCs with low content of Fe 3 O 4 -PGMA NPs (1 wt %). The incorporation of Fe 3 O 4 -PGMA NPs can be easily extended to other polymer and polymer-based composite systems and opens a new and very promising pathway toward MNP-based nondestructive flaw detection in polymeric materials.

Reliably detectable flaw size for NDE methods that use calibration

Science.gov (United States)

Koshti, Ajay M.

2017-04-01

Probability of detection (POD) analysis is used in assessing reliably detectable flaw size in nondestructive evaluation (NDE). MIL-HDBK-1823 and associated mh18232 POD software gives most common methods of POD analysis. In this paper, POD analysis is applied to an NDE method, such as eddy current testing, where calibration is used. NDE calibration standards have known size artificial flaws such as electro-discharge machined (EDM) notches and flat bottom hole (FBH) reflectors which are used to set instrument sensitivity for detection of real flaws. Real flaws such as cracks and crack-like flaws are desired to be detected using these NDE methods. A reliably detectable crack size is required for safe life analysis of fracture critical parts. Therefore, it is important to correlate signal responses from real flaws with signal responses form artificial flaws used in calibration process to determine reliably detectable flaw size.

Development of an Intelligent Ultrasonic Signature Classification Software for Discrimination of Flaws in Weldments

International Nuclear Information System (INIS)

Kim, H. J.; Song, S. J.; Jeong, H. D.

1997-01-01

Ultrasonic pattern recognition is the most effective approach to the problem of discriminating types of flaws in weldments based on ultrasonic flaw signals. In spite of significant progress in the research on this methodology, it has not been widely used in many practical ultrasonic inspections of weldments in industry. Hence, for the convenient application of this approach in many practical situations, we develop an intelligent ultrasonic signature classification software which can discriminate types of flaws in weldments based on their ultrasonic signals using various tools in artificial intelligence such as neural networks. This software shows the excellent performance in an experimental problem where flaws in weldments are classified into two categories of cracks and non-cracks. This performance demonstrates the high possibility of this software as a practical tool for ultrasonic flaw classification in weldments

Application of elastic and elastic-plastic fracture mechanics methods to surface flaws

Science.gov (United States)

McCabe, Donald E.; Ernst, Hugo A.; Newman, James C., Jr.

Fuel tanks that are a part of the External Tank assembly for the Space Shuttle are made of relatively thin 2219-T87 aluminum plate. These tanks contain about 917 m of fusion weld seam, all of which is nondestructively inspected for flaws and all those found are repaired. The tanks are subsequently proof-tested to a pressure that is sufficiently severe to cause weld metal yielding in a few local regions of the weld seam. The work undertaken in the present project was to develop a capability to predict flaw growth from undetected surface flaws that are assumed to be located in the highly stressed regions. The technical challenge was to develop R-curve prediction capability for surface cracks in specimens that contain the flaws of unusual sizes and shapes deemed to be of interest. The test techniques developed and the elastic-plastic analysis concepts adopted are presented. The flaws of interest were quite small surface cracks that were narrow-deep ellipses that served to exacerbate the technical difficulties involved.

Ultrasonographic Detection of Tooth Flaws

Science.gov (United States)

Bertoncini, C. A.; Hinders, M. K.; Ghorayeb, S. R.

2010-02-01

The goal of our work is to adapt pulse-echo ultrasound into a high resolution imaging modality for early detection of oral diseases and for monitoring treatment outcome. In this talk we discuss our preliminary results in the detection of: demineralization of the enamel and dentin, demineralization or caries under and around existing restorations, caries on occlusal and interproximal surfaces, cracks of enamel and dentin, calculus, and periapical lesions. In vitro immersion tank experiments are compared to results from a handpiece which uses a compliant delay line to couple the ultrasound to the tooth surface. Because the waveform echoes are complex, and in order to make clinical interpretation of ultrasonic waveform data in real time, it is necessary to automatically interpret the signals. We apply the dynamic wavelet fingerprint algorithms to identify and delineate echographic features that correspond to the flaws of interest in teeth. The resulting features show a clear distinction between flawed and unflawed waveforms collected with an ultrasonic handpiece on both phantom and human cadaver teeth.

Methods to establish flaw tolerances

International Nuclear Information System (INIS)

Varga, T.

1978-01-01

Three conventional methods used to establish flaw tolerances are compared with new approaches using fracture mechanics. The conventional methods are those based on (a) non-destructive testing methods; (b) fabrication and quality assurance experience; and (c) service and damage experience. Pre-requisites of fracture mechanics methods are outlined, and summaries given of linear elastic mechanics (LEFM) and elastoplastic fracture mechanics (EPFM). The latter includes discussion of C.O.D.(crack opening displacement), the J-integral and equivalent energy. Proposals are made for establishing flaw tolerances. (U.K.)

Cracking and Failure in Rock Specimen Containing Combined Flaw and Hole under Uniaxial Compression

Directory of Open Access Journals (Sweden)

Xiang Fan

2018-01-01

Full Text Available Flaw is a key factor influencing failure behavior of a fractured specimen. In the present study, rectangular-flawed specimens were prepared using sandstone to investigate the effect of flaw on failure behavior of rock. Open flaw and cylindrical hole were simultaneously precut within rock specimens using high-pressure water jet cutting technology. Five series of specimens including intact, single-hole-alone, two-hole-alone, single-hole and two-flaw, and two-hole and single-flaw blocks were prepared. Uniaxial compressive tests using a rigid servo control instrument were carried out to investigate the fracture processes of these flawed specimens. It is observed that during loading, internal stress always intensively distributed at both sidewalls of open hole, especially at midpoint of sidewalls, so rock crumb flaking was firstly observed among all sandstone specimens containing single hole or two holes. Cracking around open hole is associated with the flaw inclination angle which was observed in Series III and V. Crack easily initiated at the tips of flaw with inclination angles of 0°, 30°, and 60° but hard for 90° in Series III and V. Rock burst was the major failure mode among most tested specimens, which generally induced new cracks and finally created crater shape. Additionally, due to extrusion between blocks, new shear or tensile cracks were generated and the rock specimen surface spalled. Eventually, four typical failure processes including rock crumb flaking, crack initiation and propagation, rock burst, and second rupture, were summarized.

The behavior of shallow flaws in reactor pressure vessels

International Nuclear Information System (INIS)

Rolfe, S.T.

1991-11-01

Both analytical and experimental studies have shown that the effect of crack length, a, on the elastic-plastic toughness of structural steels is significant. The objective of this report is to recommend those research investigations that are necessary to understand the phenomenon of shallow behavior as it affects fracture toughness so that the results can be used properly in the structural margin assessment of reactor pressure vessels (RPVs) with flaws. Preliminary test results of A 533 B steel show an elevated crack-tip-opening displacement (CTOD) toughness similar to that observed for structural steels tested at the University of Kansas. Thus, the inherent resistance to fracture initiation of A 533 B steel with shallow flaws appears to be higher than that used in the current American Society of Mechanical Engineers (ASME) design curves based on testing fracture mechanics specimens with deep flaws. If this higher toughness of laboratory specimens with shallow flaws can be transferred to a higher resistance to failure in RPV design or analysis, then the actual margin of safety in nuclear vessels with shallow flaws would be greater than is currently assumed on the basis of deep-flaw test results. This elevation in toughness and greater resistance to fracture would be a very desirable situation, particularly for the pressurized-thermal shock (PTS) analysis in which shallow flaws are assumed to exist. Before any advantage can be taken of this possible increase in initiation toughness, numerous factors must be analyzed to ensure the transferability of the data. This report reviews those factors and makes recommendations of studies that are needed to assess the transferability of shallow-flaw toughness test results to the structural margin assessment of RPV with shallow flaws. 14 refs., 8 figs

Flaw evolution monitoring by acoustic emission technique

International Nuclear Information System (INIS)

Ghia, S.; Sala, A.; Lucia, A.

1986-01-01

Flaw evolution monitoring during mechanical fatigue test has been performed by acoustic emission (AE) technique. Testing on 1:5 reduced scale vessel containing fabrication defects was carried out in the frame of an European program for pressure component residual life evaluation. Characteristics of AE signals associated to flaw evolution are discussed

When high-volume PCI operators in high-volume hospitals move to lower volume hospitals-Do they still maintain high volume and quality of outcomes?

Science.gov (United States)

Lu, Tsung-Hsueh; Li, Sheng-Tun; Liang, Fu-Wen; Lee, Jo-Chi; Yin, Wei-Hsian

2017-10-31

The aim of this quasi-experimental study was to examine whether high-volume percutaneous coronary intervention (PCI) operators still maintain high volume and quality of outcomes when they moved to lower volume hospitals. Systematic reviews have indicated that high-volume PCI operators and hospitals have higher quality outcomes. However, little is known on whether high PCI volume and high quality outcomes are mainly due to operator characteristics (i.e., skill and experience) and is portable across organizations or whether it is due to hospital characteristics (i.e., equipment, team, and management system) and is less portable. We used Taiwan National Health Insurance claims data 2000-2012 to identify 98 high-volume PCI operators, 10 of whom moved from one hospital to another during the study period. We compared the PCI volume, risk-adjusted mortality ratio, and major adverse cardiovascular event (MACE) ratio before and after moving. Of the 10 high-volume operators who moved, 6 moved from high- to moderate- or low-volume hospitals, with median annual PCI volumes (interquartile range) of 130 (117-165) in prior hospitals and 54 (46-84) in subsequent hospitals (the hospital the operator moved to), and the remaining 4 moved from high to high-volume hospitals, with median annual PCI volumes (interquartile range) of 151 (133-162) in prior hospitals and 193 (178-239) in subsequent hospitals. No significant differences were observed in the risk-adjusted mortality ratios and MACE ratios between high-volume operators and matched controls before and after moving. High-volume operators cannot maintain high volume when they moved from high to moderate or low-volume hospitals; however, the quality of care is maintained. High PCI volume and high-quality outcomes are less portable and more hospital bound. © 2017 Wiley Periodicals, Inc.

Nondestructive detection of surface flaws in materials by infrared thermography

International Nuclear Information System (INIS)

Ishii, Toshimitsu; Ooka, Norikazu; Eto, Motokuni; Hoshiya, Taiji; Okamoto, Yoshizo

1999-01-01

Infrared thermography is one of the useful remote sensing techniques applied to the nondestructive detection of surface flaws in materials. Radiation temperatures of the specimen surface and surrounding walls as well as the difference in them are crucial factors to detect surface flaws from thermal images, and it is essential that these factors be properly evaluated beforehand in order to detect the flaws by infrared thermography. In this study, the radiation temperature of nuclear graphite specimens heated uniformly was measured by infrared thermography to evaluate the radiation characteristics such as emissivity, radiosity coefficient and variation of radiation temperature. The influence of the temperature difference between the test specimen and its surroundings on the limit of detection of pinhole flaws was discussed on the basis of the thermal images of graphite specimen with surface flaws. It was found that the thermal image of a small flaw was clearly visible with increase in the temperature difference. (author)

Ultrasonic simulation studies for sizing of planar flaws in thick carbon steel welds

International Nuclear Information System (INIS)

Prakash, Alok

2015-01-01

Ultrasonic non-destructive testing typically involves detection of flaws that may affect the integrity of component under test. Once detected, the flaw is sized for its critical dimensions and its nature. The detection of flaw in the component by ultrasonic test is based on the principle of echo or reflection. Once the echo from a flaw is received, there are several approaches for analyzing the signal so that more and accurate information is obtained on the size of the flaw and its nature. The 6dB drop method is commonly used for sizing of flaws. This technique is based on determining the end points where the ultrasonic signal amplitude from the flaw drops to half of the peak amplitude. Though this method works well for large flaws whose size is larger than the beam width, it has a tendency to oversize the flaw which is smaller than the beam dimensions. In addition to beam divergence, flaw sizing also depends upon the orientation of the flaw with respect to incident sound beam. The paper describes the results of simulation studies on ultrasonic response from planar flaws of various orientations, their imaging and the methodology to be adopted for their accurate depth sizing. The paper also describes the experimental results to validate the flaw sizing approach

Flaw evaluation of pressure vessel in pressurized water reactor

International Nuclear Information System (INIS)

Park, Ki Sung; Kim, Min Geol; Jeon, Chae Hong; Rhim, Soon Hyung; Kim, Seung Tae

1999-01-01

Flaw evaluation should be performed to determine the acceptance of a surface or a subsurface flaw detected during the in-service inspection without any repair or replacement. In this paper, the evaluation methodology and procedure were established according to ASME code Sec. XI and the evaluation program was coded. Using this program, a field engineer who doesn't have enough knowledge on fracture mechanics may be able to perform prompt and accurate flaw evaluation on site and decide whether a detected flaw be allowable or not. Analysis results were compared with those obtained from Westinghouse program called KCAL and FCG. Both results made good agreement and accuracy of the program developed in this paper was verified.=20

A new digital correlation flaw detection system

International Nuclear Information System (INIS)

Lee, B.B.; Furgason, E.S.

1981-01-01

A new portable digital random signal flaw detection system is described which uses a digital delay line to replace the acoustic delay line of the original random signal system. Using this new system, a comparison was made between the two types of transmit signals which have been used in previous systems--m-sequences and random signals. This comparison has not been possible with these previous correlation flaw detection systems. Results indicated that for high-speed short code operation, the m-sequences produced slightly lower range sidelobes than typical samples of a clipped random signal. For normal long code operation, results indicated that system performance is essentially equivalent in resolution and signal-to-noise ratio using either m-sequences or clipped and sampled random signals. Further results also showed that for normal long code operation, the system produces outputs equivalent in resolution to pulse-echo systems, but with the added benefit of signal-to-noise ratio enhancement

Flaw detection device

International Nuclear Information System (INIS)

Sasahara, Toshihiko

1998-01-01

The present invention provides a device for detecting welded portions of a reactor pressure vessel. Namely, the device of the present invention comprises (1) a casing to be disposed on the surface to be detected, (2) a probe driving means loaded to the casing, (3) a probe driven along the surface to be detected and (4) a pressure reduction means for keeping the hollow portion in the casing to an evacuated atmosphere. The casing comprises a flexible suction edge to be tightly in contact with the surface to be tested for maintaining the air tight state, (6) a guide wheel for moving the casing along the surface to be tested and (7) a handle for performing transferring operation. The flaw detection device thus constituted has following features. The working efficiency upon conducting detection is improved. The influence of the weight of the device on the detection is small. The device can be applied on the surface of a nonmagnetic material. The efficiency for the flaw detection can be improved. (I.S.)

Advances in flaw evaluation procedures and acceptance criteria for reactor piping

International Nuclear Information System (INIS)

Gamble, R.M.; Zahoor, A.; Norris, D.M.

1986-01-01

During the past several years, intergranular stress corrosion cracks (IGSCC) have been detected in stainless steel piping in boiling water reactors (BWRs) and have resulted in an increased number of flaw evaluations. To reduce the outage time associated with evaluating IGSCC, various research and ASME code groups have spent significant effort to provide utility personnel with efficient means to detect, classify, and size flaws, and to determine suitability for return to service for flawed stainless steel piping. One of the several nondestructive evaluation technologies that has received considerable attention is fracture mechanics, the discipline that considers the failure of flawed material. Fracture mechanics can be used to answer two key questions concerning return to service of flawed pipe: (a) what is the largest flaw size that can be returned to service and still maintain adequate safety margins at the applied loads, and (b) how much operating time remains before the crack reaches the largest allowable size? The purpose of this paper is to provide an overview of the recently developed ASME code Section XI flaw size evaluation procedure and acceptance criteria for stainless steel piping and their application by BWR owners to efficiently determine if flaws found by nondestructive examination are acceptable for continued service

Advances in flaw evaluation procedures and acceptance criteria for reactor piping

Energy Technology Data Exchange (ETDEWEB)

Gamble, R.M.; Zahoor, A.; Norris, D.M.

1986-01-01

During the past several years, intergranular stress corrosion cracks (IGSCC) have been detected in stainless steel piping in boiling water reactors (BWRs) and have resulted in an increased number of flaw evaluations. To reduce the outage time associated with evaluating IGSCC, various research and ASME code groups have spent significant effort to provide utility personnel with efficient means to detect, classify, and size flaws, and to determine suitability for return to service for flawed stainless steel piping. One of the several nondestructive evaluation technologies that has received considerable attention is fracture mechanics, the discipline that considers the failure of flawed material. Fracture mechanics can be used to answer two key questions concerning return to service of flawed pipe: (a) what is the largest flaw size that can be returned to service and still maintain adequate safety margins at the applied loads, and (b) how much operating time remains before the crack reaches the largest allowable size. The purpose of this paper is to provide an overview of the recently developed ASME code Section XI flaw size evaluation procedure and acceptance criteria for stainless steel piping and their application by BWR owners to efficiently determine if flaws found by nondestructive examination are acceptable for continued service.

Determination of K-factors for arbitrarily shaped flaws at pressure vessel nozzle corners

International Nuclear Information System (INIS)

Bryson, J.W.

1979-01-01

Photoelastic and finite element studies are being conducted to determine Mode I stress intensity factor distributions along arbitrarily shaped flaw fronts at pressure vessel nozzle corners. Comparisons of results from NOZ-FLAW, BIGIF, and the photoelastic studies showed that (1) good agreement was obtained between NOZ-FLAW and the photoelastically determined K 1 's for the deep flaw in an ITV model, (2) good agreement was obtained between NOZ-FLAW BIGIF for shallow and moderately deep flaws in a BWR model, and (3) less satisfactory agreement was obtained between NOZ- FLAW and the photoelastic results for the BWR models, particularly for moderately deep to deep flaws. Attempts are presently being made at understanding and explaining the discrepancies between the two

Estimation of Back-Surface Flaw Depth by Laminated Piezoelectric Highpolymer Film

Directory of Open Access Journals (Sweden)

Akinobu YAMAMOTO

2009-08-01

Full Text Available Piezoelectric thin films have been used to visualize back surface flaws in plates. If the plate with a surface flaw is deformed, the strain distribution appears on the other surface reflecting the location and the shape of the flaw. Such surface strain distribution can be transformed into the electric potential distribution on the piezoelectric film mounted on the plate surface. This paper deals with a NDE technique to estimate the depth of a back-surface flaw from the electric potential distribution on a laminated piezoelectric thin film. It is experimentally verified that the flaw depth can be exactly estimated by the peak height of the electric potential distribution.

Temperature dependence of luminescence for different surface flaws in high purity silica glass

International Nuclear Information System (INIS)

Fournier, J.; Grua, P.; Neauport, J.; Fargin, E.; Jubera, V.; Talaga, D.; Del Guerzo, A.; Raffy, G.; Jouannigot, S.

2013-01-01

In situ temperature dependence of the Photoluminescence under 325 nm irradiation is used to investigate defect populations existing in different surface flaws in high purity fused silica. Five photoluminescence bands peaking at 1.9, 2.1, 2.3, 2.63 and 3.11 eV have been detected in the spectral area ranging from 1.6 up to 3.6 eV. The Gaussian deconvolution of spectra allows dividing the five luminescence bands in two categories. The former corresponds to bands showing a significant intensity enhancement while temperature decreases; the latter corresponds to bands remaining insensitive to the temperature evolution. Such a behavior brings new information on defects involved in laser damage mechanism at 351 nm in nanosecond regime. (authors)

Evaluation of canister weld flaw depth for concrete storage cask

Energy Technology Data Exchange (ETDEWEB)

Moon, Tae Chul; Cho, Chun Hyung [Korea Radioactive Waste Agency, Daejeon (Korea, Republic of); Jung, Sung Hun; Lee, Young Oh; Jung, In Su [Korea Nuclear Engineering and Service Corp, Daejeon (Korea, Republic of)

2017-03-15

Domestically developed concrete storage casks include an internal canister to maintain the confinement integrity of radioactive materials. In this study, we analyzed the depth of flaws caused by loads that propagate canister weld cracks under normal, off-normal and accident conditions, and evaluated the maximum allowable weld flaw depth needed to secure the structural integrity of the canister weld and to reduce the welding time of the internal canister lid of the concrete storage cask. Structural analyses for normal, off-normal and accident conditions were performed using the general-purpose finite element analysis program ABAQUS; the allowable flaw depth was assessed according to ASME B and PV Code Section XI. Evaluation results revealed an allowable canister weld flaw depth of 18.75 mm for the concrete storage cask, which satisfies the critical flaw depth recommended in NUREG-1536.

Ductile fracture of cylindrical vessels containing a large flaw

Science.gov (United States)

Erdogan, F.; Irwin, G. R.; Ratwani, M.

1976-01-01

The fracture process in pressurized cylindrical vessels containing a relatively large flaw is considered. The flaw is assumed to be a part-through or through meridional crack. The flaw geometry, the yield behavior of the material, and the internal pressure are assumed to be such that in the neighborhood of the flaw the cylinder wall undergoes large-scale plastic deformations. Thus, the problem falls outside the range of applicability of conventional brittle fracture theories. To study the problem, plasticity considerations are introduced into the shell theory through the assumptions of fully-yielded net ligaments using a plastic strip model. Then a ductile fracture criterion is developed which is based on the concept of net ligament plastic instability. A limited verification is attempted by comparing the theoretical predictions with some existing experimental results.

A time-domain synthetic aperture ultrasound imaging method for material flaw quantification with validations on small-scale artificial and natural flaws.

Science.gov (United States)

Guan, Xuefei; He, Jingjing; Rasselkorde, El Mahjoub

2015-02-01

A direct time-domain reconstruction and sizing method of synthetic aperture focusing technique (SAFT) is developed to improve the spatial resolution and sizing accuracy for phased-array ultrasonic inspections. The basic idea of the reconstruction algorithm is to coherently superimpose multiple A-scan measurements, incorporating the phase information of the sampling points. The algorithm involves data mapping and in-phase summation according to time-of-flight (TOF). Data mapping refers to the process of placing each of the sampling points to a two-/three-dimensional grid that represents the geometry model of the object being inspected. The value for each of the cells of the grid is a summation of all sampling points mapped into the cell. A sizing method based on the concept of 6 dB-drop is proposed to characterize the flaw boundary. The extents, orientation and the shape of the flaw can then be inferred to provide more information for life assessment calculations. Lab experiments are performed using a 10 MHz phased-array ultrasonic transducer to collect data from a cylinder material block with closely spaced artificial flaws and from a material block with a natural flaw. The developed method is used to process the experimental data to characterize the flaws. Using the developed method, the improvement of spatial resolution is observed. Results indicate that four closely spaced 0.794 mm-diameter flat-bottomed holes are clearly identified, and the quantification of size and orientation of the natural flaw is very close to the actual measurement made from digital microscopy after cutting the testing piece apart. Copyright © 2014 Elsevier B.V. All rights reserved.

Flaw density examinations of a clad boiling water reactor pressure vessel segment

International Nuclear Information System (INIS)

Cook, K.V.; McClung, R.W.

1986-01-01

Flaw density is the greatest uncertainty involved in probabilistic analyses of reactor pressure vessel failure. As part of the Heavy-Section Steel Technology (HSST) Program, studies have been conducted to determine flaw density in a section of reactor pressure vessel cut from the Hope Creek Unit 2 vessel [nominally 0.7 by 3 m (2 by 10 ft)]. This section (removed from the scrapped vessel that was never in service) was evaluated nondestructively to determine the as-fabricated status. We had four primary objectives: (1) evaluate longitudinal and girth welds for flaws with manual ultrasonics, (2) evaluate the zone under the nominal 6.3-mm (0.25-in.) clad for cracking (again with manual ultrasonics), (3) evaluate the cladding for cracks with a high-sensitivity fluorescent penetrant method, and (4) determine the source of indications detected

Comparison of evaluation method for planar flaw in pressure tube

International Nuclear Information System (INIS)

Choi, Sung Nam; Kim, Hyung Nam; Yoo, Hyun Joo; Hwang, Won Gul

2009-01-01

CSA N285.4-94 requires the periodic inservice inspection and surveillance of pressure tubes in operating CANDU nuclear power reactors. If the inspection results reveal a flaw exceeding the acceptance criteria of the Code, the flaw must be evaluated to determine if the pressure is acceptable for continued service. Currently, the flaw evaluation methodology and acceptance criteria specified in CSA N285.8-05, 'Technical requirements for in-service evaluation of zirconium alloy pressure tubes in CANDU reactors'. The Code is applicable to zirconium alloy pressure tubes. The evaluation methodology for a crack-like flaw is similar to that of FFSG(Fitness For Service Guideline for Zirconium alloy pressure in operation CANDU) used now. The object of this paper is to address the fracture initiation and plastic collapse evaluation for the planar flaw as it applies to the pressure tube on Wolsong NPP.

An intelligent software approach to ultrasonic flaw classification in weldments

International Nuclear Information System (INIS)

Song, Sung Jin; Kim, Hak Joon; Lee, Hyun

1997-01-01

Ultrasonic pattern recognition is the most effective approach to the problem of discriminating types of flaws in weldments based on ultrasonic flaw signals. In spite of significant progress on this methodology, it has not been widely used in practical ultrasonic inspection of weldments in industry. Hence, for the convenient application of this approach in many practical situations, we develop an intelligent ultrasonic signature classification software which can discriminate types of flaws in weldments using various tools in artificial intelligence such as neural networks. This software shows excellent performances in an experimental problem where flaws in weldments are classified into two categories of cracks and non-cracks.

Evaluation of Fatigue Crack Initiation for Volumetric Flaw in Pressure Tube

International Nuclear Information System (INIS)

Choi, Sung Nam; Yoo, Hyun Joo

2005-01-01

CAN/CSA.N285.4-94 requires the periodic inservice inspection and surveillance of pressure tubes in operating CANDU nuclear power reactors. If the inspection results reveal a flaw exceeding the acceptance criteria of the Code, the flaw must be evaluated to determine if the pressure is acceptable for continued service. Currently, the flaw evaluation methodology and acceptance criteria specified in CSA-N285.05-2005, 'Technical requirements for in-service evaluation of zirconium alloy pressure tubes in CANDU reactors'. The Code is applicable to zirconium alloy pressure tubes. The evaluation methodology for a crack-like flaw is similar to that of ASME B and PV Sec. XI, 'Inservice Inspection of Nuclear Power Plant Components'. However, the evaluation methodology for a blunt volumetric flaw is described in CSA-N285.05-2005 code. The object of this paper is to address the fatigue crack initiation evaluation for the blunt volumetric flaw as it applies to the pressure tube at Wolsong NPP

Delayed Hydride Cracking Mechanism in Zirconium Alloys and Technical Requirements for In-Service Evaluation of Zr-2.5Nb Tubes with Flaws

International Nuclear Information System (INIS)

Kim, Young Suk

2007-01-01

In association with periodic inspection of CANDU nuclear power plant components, Canadian Standards Association issued CSA N285.8 in 2005 as technical requirements for in-service evaluation of zirconium alloy pressure tubes in CANDU reactors. This first version, CSA N285.8 involves procedures for, firstly, the evaluation of pressure tube flaws, secondly, the evaluation of pressure tube to calandria tube contact and, thirdly, the assessment of a reactor core, and material properties and derived quantities. The evaluation of pressure tube flaws includes delayed hydride cracking evaluation the procedures of which are stipulated based on the existing delayed hydride cracking models. For example, the evaluation of flaw-tip hydride precipitation during reactor cooldown involves a procedure to calculate the equilibrium hydrogen equivalent concentration in solution at the flaw tip, Htipas follows: Htip=Hfexp[- (VH delta no.)/RT], where Hf is the total bulk hydrogen equivalent concentration, VH partial molar volume of hydrogen in zirconium, δ a difference in hydrostatic stress between the bulk and the crack tip. When Htip ≥TSSP at temperature, then flaw-tip hydride is predicted to precipitate. Eq. (1) suggests that hydrogen concentration at the crack tip would increase due to an work energy given by the difference in the hydrostatic stress

Statistical flaw strength distributions for glass fibres: Correlation between bundle test and AFM-derived flaw size density functions

International Nuclear Information System (INIS)

Foray, G.; Descamps-Mandine, A.; R’Mili, M.; Lamon, J.

2012-01-01

The present paper investigates glass fibre flaw size distributions. Two commercial fibre grades (HP and HD) mainly used in cement-based composite reinforcement were studied. Glass fibre fractography is a difficult and time consuming exercise, and thus is seldom carried out. An approach based on tensile tests on multifilament bundles and examination of the fibre surface by atomic force microscopy (AFM) was used. Bundles of more than 500 single filaments each were tested. Thus a statistically significant database of failure data was built up for the HP and HD glass fibres. Gaussian flaw distributions were derived from the filament tensile strength data or extracted from the AFM images. The two distributions were compared. Defect sizes computed from raw AFM images agreed reasonably well with those derived from tensile strength data. Finally, the pertinence of a Gaussian distribution was discussed. The alternative Pareto distribution provided a fair approximation when dealing with AFM flaw size.

Real time automatic discriminating of ultrasonic flaws

International Nuclear Information System (INIS)

Suhairy Sani; Mohd Hanif Md Saad; Marzuki Mustafa; Mohd Redzwan Rosli

2009-01-01

This paper is concerned with the real time automatic discriminating of flaws from two categories; i. cracks (planar defect) and ii. Non-cracks (volumetric defect such as cluster porosity and slag) using pulse-echo ultrasound. The raw ultrasonic flaws signal were collected from a computerized robotic plane scanning system over the whole of each reflector as the primary source of data. The signal is then filtered and the analysis in both time and frequency domain were executed to obtain the selected feature. The real time feature analysis techniques measured the number of peaks, maximum index, pulse duration, rise time and fall time. The obtained features could be used to distinguish between quantitatively classified flaws by using various tools in artificial intelligence such as neural networks. The proposed algorithm and complete system were implemented in a computer software developed using Microsoft Visual BASIC 6.0 (author)

Development of the Automated Ultrasonic Testing System for Inspection of the flaw in the Socket Weldment

International Nuclear Information System (INIS)

Lee, Jeong Ki; Park, Moon Ho; Park, Ki Sung; Lee, Jae Ho; Lim, Sung Jin

2004-01-01

Socket weldment used to change the flow direction of fluid nay have flaws such as lack of fusion and cracks. Liquid penetrant testing or Radiography testing have been applied as NDT methods for flaw detection of the socket weldment. But it is difficult to detect the flaw inside of the socket weldment with these methods. In order to inspect the flaws inside the socket weldment, a ultrasonic testing method is established and a ultrasonic transducer and automated ultrasonic testing system are developed for the inspection. The automated ultrasonic testing system is based on the portable personal computer and operated by the program based Windows 98 or 2000. The system has a pulser/receiver, 100MHz high speed A/D board, and basic functions of ultrasonic flaw detector using the program. For the automated testing, motion controller board of ISA interface type is developed to control the 4-axis scanner and a real time iC-scan image of the automated testing is displayed on the monitor. A flaws with the size of less than 1mm in depth are evaluated smaller than its actual site in the testing, but the flaws larger than 1mm appear larger than its actual size on the contrary. This tendency is shown to be increasing as the flaw size increases. h reliable and objective testing results are obtained with the developed system, so that it is expected that it can contribute to safety management and detection of repair position of pipe lines of nuclear power plants and chemical plants

Bounding the conservatism in flaw-related variables for pressure vessel integrity analyses

International Nuclear Information System (INIS)

Foulds, J.R.; Kennedy, E.L.

1993-01-01

The fracture mechanics-based integrity analysis of a pressure vessel, whether performed deterministically or probabilistically, requires use of one or more flaw-related input variables, such as flaw size, number of flaws, flaw location, and flaw type. The specific values of these variables are generally selected with the intent to ensure conservative predictions of vessel integrity. These selected values, however, are largely independent of vessel-specific inspection results, or are, at best, deduced by ''conservative'' interpretation of vessel-specific inspection results without adequate consideration of the pertinent inspection system performance (reliability). In either case, the conservatism associated with the flaw-related variables chosen for analysis remains examination (NDE) technology and the recently formulated ASME Code procedures for qualifying NDE system capability and performance (as applied to selected nuclear power plant components) now provides a systematic means of bounding the conservatism in flaw-related input variables for pressure vessel integrity analyses. This is essentially achieved by establishing probabilistic (risk)-based limits on the assigned variable values, dependent upon the vessel inspection results and on the inspection system unreliability. Described herein is this probabilistic method and its potential application to: (i) defining a vessel-specific ''reference'' flaw for calculating pressure-temperature limit curves in the deterministic evaluation of pressurized water reactor (PWR) reactor vessels, and (ii) limiting the flaw distribution input to a PWR reactor vessel-specific, probabilistic integrity analysis for pressurized thermal shock loads

Applicability of Alignment and Combination Rules to Burst Pressure Prediction of Multiple-flawed Steam Generator Tube

Energy Technology Data Exchange (ETDEWEB)

Lee, Myeong Woo; Kim, Ji Seok; Kim, Yun Jae [Korea University, Seoul (Korea, Republic of); Jeon, Jun Young [Doosan Heavy Industries and Consruction, Seoul (Korea, Republic of); Lee, Dong Min [Korea Plant Service and Engineering, Technical Research and Development Institute, Naju (Korea, Republic of)

2016-05-15

Alignment and combination rules are provided by various codes and standards. These rules are used to determine whether multiple flaws should be treated as non-aligned or as coplanar, and independent or combined flaws. Experimental results on steam generator (SG) tube specimens containing multiple axial part-through-wall (PTW) flaws at room temperature (RT) are compared with assessment results based on the alignment and combination rules of the codes and standards. In case of axial collinear flaws, ASME, JSME, and BS7910 treated multiple flaws as independent flaws and API 579, A16, and FKM treated multiple flaws as combined single flaw. Assessment results of combined flaws were conservative. In case of axial non-aligned flaws, almost flaws were aligned and assessment results well correlate with experimental data. In case of axial parallel flaws, both effective flaw lengths of aligned flaws and separated flaws was are same because of each flaw length were same. This study investigates the applicability of alignment and combination rules for multiple flaws on the failure behavior of Alloy 690TT steam generator (SG) tubes that widely used in the nuclear power plan. Experimental data of burst tests on Alloy 690TT tubes with single and multiple flaws that conducted at room temperature (RT) by Kim el al. compared with the alignment rules of these codes and standards. Burst pressure of SG tubes with flaws are predicted using limit load solutions that provide by EPRI Handbook.

Irradiation effects and the duplication of detected flaws in service

International Nuclear Information System (INIS)

Mager, T.R.

1976-01-01

ASME Code procedure for evaluating the acceptability of flaws detected during in-service inspection is revised. Critical crack size for instability is proposed as criteria for detected flaws in operating plants

Flaw tolerance vs. performance: A tradeoff in metallic glass cellular structures

International Nuclear Information System (INIS)

Chen, Wen; Liu, Ze; Robinson, Hannah Mae; Schroers, Jan

2014-01-01

Stochastic cellular structures are prevalent in nature and engineering materials alike. They are difficult to manipulate and study systematically and almost always contain imperfections. To design and characterize various degrees of imperfections in perfect periodic, stochastic and natural cellular structures, we fabricate a broad range of metallic glass cellular structures from perfectly periodic to highly stochastic by using a novel artificial microstructure approach based on thermoplastic replication of metallic glasses. For these cellular structures, precisely controlled imperfections are implemented and their effects on the mechanical response are evaluated. It is found that the mechanical performance of the periodic structures is generally superior to that of the stochastic structures. However, the stochastic structures experience a much higher tolerance to flaws than the periodic structure, especially in the plastic regime. The different flaw tolerance is explained by the stress distribution within the various structures, which leads to an overall 'strain-hardening' behavior of the stochastic structure compared to a 'strain-softening' behavior in the periodic structure. Our findings reveal how structure, 'strain-hardening' and flaw tolerance are microscopically related in structural materials

Detection of flaws below curved surfaces

International Nuclear Information System (INIS)

Elsley, R.K.; Addison, R.C.; Graham, L.J.

1983-01-01

A measurement model has been developed to describe ultrasonic measurements made with circular piston transducers in parts with flat or cylindrically curved surfaces. The model includes noise terms to describe electrical noise, scatterer noise and echo noise as well as effects of attenuation, diffraction and Fresnel loss. An experimental procedure for calibrating the noise terms of the model was developed. Experimental measurements were made on a set of known flaws located beneath a cylindrically curved surface. The model was verified by using it to correct the experimental measurements to obtain the absolute scattering amplitude of the flaws. For longitudinal wave propagation within the part, the derived scattering amplitudes were consistent with predictions at internal angles of less than 30 0 . At larger angles, focusing and aberrations caused a lack of agreement; the model needs further refinement in this case. For shear waves, it was found that the frequency for optimum flaw detection in the presence of material noise is lower than that for longitudinal waves; lower frequency measurements are currently in progress. The measurement model was then used to make preliminary predictions of the best experimental measurement technique for the detection of cracks located under cylindrically curved surfaces

Common methodological flaws in economic evaluations.

Science.gov (United States)

Drummond, Michael; Sculpher, Mark

2005-07-01

Economic evaluations are increasingly being used by those bodies such as government agencies and managed care groups that make decisions about the reimbursement of health technologies. However, several reviews of economic evaluations point to numerous deficiencies in the methodology of studies or the failure to follow published methodological guidelines. This article, written for healthcare decision-makers and other users of economic evaluations, outlines the common methodological flaws in studies, focussing on those issues that are likely to be most important when deciding on the reimbursement, or guidance for use, of health technologies. The main flaws discussed are: (i) omission of important costs or benefits; (ii) inappropriate selection of alternatives for comparison; (iii) problems in making indirect comparisons; (iv) inadequate representation of the effectiveness data; (v) inappropriate extrapolation beyond the period observed in clinical studies; (vi) excessive use of assumptions rather than data; (vii) inadequate characterization of uncertainty; (viii) problems in aggregation of results; (ix) reporting of average cost-effectiveness ratios; (x) lack of consideration of generalizability issues; and (xi) selective reporting of findings. In each case examples are given from the literature and guidance is offered on how to detect flaws in economic evaluations.

A study on the dimensioning of flaws by acoustical holography

International Nuclear Information System (INIS)

Yamamoto, Michio; Ando, Tomozumi; Enami, Koji; Yajima, Minoru; Fukui, Shigetaka.

1978-01-01

As a means of evaluating the safety of flawed pressure vessels and other structures against fracture, fracture mechanics has come to be applied. For the application of fracture mechanics it is necessary to get information concerning the sizes and shapes of flaws. The ultrasonic flaw detection method that is widely used as a nondestructive inspection method cannot measure the sizes and shapes of flaws accurately. Considering that acoustical holography is an useful means for the dimensioning of flaws, we performed basic tests on this method and obtained the following results: (1) The measured values of artificial flaws (flat bottom drilled holes: 5 - 36 mm) made on a steel plate of 150 mm thick showed a good linear relation with their actual sizes and scatter in the measured values was +-3 - 6 mm. (2) The measured values of fatigue cracks (length: 5 - 57 mm) introduced into a steel plate of 150 mm thick also showed a good linear relation with their actual sizes and scatter in the measured values was +-3 mm. (3) It was found that acoustical holography can also be applied to heavy section cast steels. (4) The method of correcting distortion caused by curved surface was investigated by computer-aided simulation and it was considered that such distortion can be corrected by radial scanning of a transducer. (author)

A dynamic fatigue study of soda-lime silicate and borosilicate glasses using small scale indentation flaws

International Nuclear Information System (INIS)

Dabbs, T.P.; Lawn, B.R.; Kelly, P.L.

1982-01-01

The dynamic fatigue characteristics of two glasses, soda-lime silicate and borosilicate, in water have been studied using a controlled indentation flaw technique. It is argued that the indentation approach offers several advantages over more conventional fatigue testing procedures: (i) the reproducibility of data is relatively high, eliminating statistics as a basis of analysis: (ii) the flaw ultimately responsible for failure is well defined and may be conveniently characterised before and after (and during, if necessary) the strength test; (iii) via adjustment of the indentation load, the size of the flaw can be suitably predetermined. Particular attention is devoted to the third point because of the facility it provides for systematic investigation of the range of flaw sizes over which macroscopic crack behaviour remains applicable. The first part of the paper summarises the essential fracture mechanics theory of the extension of an indentation flaw to failure. In the next part of the paper the results of dynamic fatigue tests on glass rods in distilled water are described. Data are obtained for Vickers indentation loads in the range 0.05 to 100 N, corresponding to contact dimensions of 2 to 100 μm. Finally, the implications of the results in relation to the response of 'natural' flaws are discussed. (author)

Modeling the X-ray Process, and X-ray Flaw Size Parameter for POD Studies

Science.gov (United States)

Koshti, Ajay M.

2014-01-01

Nondestructive evaluation (NDE) method reliability can be determined by a statistical flaw detection study called probability of detection (POD) study. In many instances, the NDE flaw detectability is given as a flaw size such as crack length. The flaw is either a crack or behaving like a crack in terms of affecting the structural integrity of the material. An alternate approach is to use a more complex flaw size parameter. The X-ray flaw size parameter, given here, takes into account many setup and geometric factors. The flaw size parameter relates to X-ray image contrast and is intended to have a monotonic correlation with the POD. Some factors such as set-up parameters, including X-ray energy, exposure, detector sensitivity, and material type that are not accounted for in the flaw size parameter may be accounted for in the technique calibration and controlled to meet certain quality requirements. The proposed flaw size parameter and the computer application described here give an alternate approach to conduct the POD studies. Results of the POD study can be applied to reliably detect small flaws through better assessment of effect of interaction between various geometric parameters on the flaw detectability. Moreover, a contrast simulation algorithm for a simple part-source-detector geometry using calibration data is also provided for the POD estimation.

Estimating probable flaw distributions in PWR steam generator tubes

International Nuclear Information System (INIS)

Gorman, J.A.; Turner, A.P.L.

1997-01-01

This paper describes methods for estimating the number and size distributions of flaws of various types in PWR steam generator tubes. These estimates are needed when calculating the probable primary to secondary leakage through steam generator tubes under postulated accidents such as severe core accidents and steam line breaks. The paper describes methods for two types of predictions: (1) the numbers of tubes with detectable flaws of various types as a function of time, and (2) the distributions in size of these flaws. Results are provided for hypothetical severely affected, moderately affected and lightly affected units. Discussion is provided regarding uncertainties and assumptions in the data and analyses

Analysis of portable gamma flaw detectors concerning radiation hygiene

International Nuclear Information System (INIS)

Makarova, T.V.

1982-01-01

Design and shields of gamma flaw detectors as one of the main factors responsible for personnel dose were studied. The analysis was conducted using the results of radiation hygienic surveys of gamma flaw detection laboratories functioning constantly in Estonia. It is shown that recently the replacement of GUP apparatuses by flaw detectors of RID and ''Gamma-RID'' (types which have design and shielding advantages is observed. However personnel doses have not reduced considerably for the last 10 years. This fact is attributed to design disadvantages of the RID and ''Gamma-RID'' apparatuses the removing of which will give the decreasing of annual personnel dose by 80 %

Flaw evaluation methodology for class 2, 3 components in light water reactors

International Nuclear Information System (INIS)

Miura, Naoki; Kashima, Koichi; Miyazaki, Katsumasa; Hasegawa, Kunio; Oritani, Naohiko

2006-01-01

It is quite important to validate the structural integrity of operating plant components as aged LWR plants are gradually increasing in Japan. The rules on fitness-for-service for nuclear power plants constituted by the JSME provides flaw evaluation methodology. They are mainly focused on Class 1 components, while flaw evaluation criteria for Class 2, 3 components are not consolidated. As such, they also required from the viewpoints of in-service inspection request, reduction of operating cost and systematization of consistent code/standard. In this study, basic concept of flaw evaluation for Class 2, 3 piping was considered, and it is concluded that the same evaluation procedure as Class 1 piping in the current rules is applicable. Some technical issues on practical flaw evaluation for Class 2, 3 piping were listed up, and a countermeasure for each issue was devised. Especially, both allowable flaw sizes in acceptance standards and critical flaw sizes in acceptance criteria have to be determined in consideration of degraded fracture toughness. (author)

Comparison of three flaw-location methods for automated ultrasonic testing

International Nuclear Information System (INIS)

Seiger, H.

1982-01-01

Two well-known methods for locating flaws by measurement of the transit time of ultrasonic pulses are examined theoretically. It is shown that neither is sufficiently reliable for use in automated ultrasonic testing. A third method, which takes into account the shape of the sound field from the probe and the uncertainty in measurement of probe-flaw distance and probe position, is introduced. An experimental comparison of the three methods indicates that use of the advanced method results in more accurate location of flaws. (author)

Effect of combined loading on pipe flaw evaluation criteria

International Nuclear Information System (INIS)

Miura, Naoki; Chung Yeonki

1999-01-01

Considering a rational maintenance rule of Light Water Reactor piping, reliable flaw evaluation criteria are essential to determine how a detected flaw is detrimental to continuous plant operation. Ductile fracture is one of the dominant failure modes to be considered for carbon steel piping, and can be analyzed by the elastic-plastic fracture mechanics. Currently the analytical results are provided as flaw evaluation criteria using load correction factors such like the Z-factor in ASME Code Section 6. The present correction factors were conventionally determined taken a conservatism and a simplicity into account, however, the effect of internal pressure which would be an important factor under an actual plant condition was not adequately considered. Recently, a J-estimation scheme, 'LBB.ENGC' for ductile fracture analysis of circumferentially through-wall-cracked pipes subjected to combined loading was newly developed to have a better prediction with more realistic manner. This method is explicitly incorporated the contribution of both bending and tension due to internal pressure by means of the scheme compatible with an arbitrary combined loading history. In this paper, the effect of internal pressure on the flaw evaluation criteria was investigated using the new J-estimation scheme. A correction factor based on the new J-estimation scheme was compared with the present correction factors, and the predictability of the current flaw evaluation criteria was quantitatively evaluated in consideration of internal pressure. (author)

Evaluation of Effect by Internal Flow on Ultrasonic Testing Flaw Sizing in Piping

International Nuclear Information System (INIS)

Lee, Jeong Seok; Yoon, Byung Sik; Kim, Yong Sik

2013-01-01

In this study, the ultrasonic amplitude difference between air filled and water filled piping in nuclear power plant is compared by modeling approach. In this study, ultrasonic amplitude differences between air and water filled pipe are evaluated by modeling approach. Consequently, we propose the following results. The ultrasonic amplitude difference between air and water filled condition is measured by lower than 1 dB in modeling calculation. The flaw length sizing error between air and water filled condition shows same results based on 12 dB drop method even thought the amplitude difference is 1 dB. Most of the piping welds in nuclear power plants are inspected periodically using ultrasonic techniques to detect service-induced flaws such as IGSCC cracking. The inspection results provide information such as location, maximum amplitude response, ultrasonic length, height and finally the nature or flaw pattern. The founded flaw in ultrasonic inspection is accepted or rejected based on these information. Specially, the amplitude of flaw response is very important to estimate the flaw size. Currently the ultrasonic inspections in nuclear power plant components are performed by specific inspection procedure which describing inspection technique include inspection system, calibration methodology and flaw characterizing methodology. To perform ultrasonic inspection during in-service inspection, reference gain should be established before starting ultrasonic inspection by requirement of ASME code. This reference gain used as basic criteria to evaluate flaw sizing. Sometimes, a little difference in establishing reference gain between calibration and field condition can lead to deviation in flaw sizing. Due to this difference, the inspection result may cause flaw sizing error

Development of an intelligent system for ultrasonic flaw classification in weldments

International Nuclear Information System (INIS)

Song, Sung-Jin; Kim, Hak-Joon; Cho, Hyeon

2002-01-01

Even though ultrasonic pattern recognition is considered as the most effective and promising approach to flaw classification in weldments, its application to the realistic field inspection is still very limited due to the crucial barriers in cost, time and reliability. To reduce such barriers, previously we have proposed an intelligent system approach that consisted of the following four ingredients: (1) a PC-based ultrasonic testing (PC-UT) system; (2) an effective invariant ultrasonic flaw classification algorithm; (3) an intelligent flaw classification software; and (4) a database with abundant experimental flaw signals. In the present work, for performing the ultrasonic flaw classification in weldments in a real-time fashion in many real word situations, we develop an intelligent system, which is called the 'Intelligent Ultrasonic Evaluation System (IUES)' by the integration of the above four ingredients into a single, unified system. In addition, for the improvement of classification accuracy of flaws, especially slag inclusions, we expand the feature set by adding new informative features, and demonstrate the enhanced performance of the IUES with flaw signals in the database constructed previously. And then, to take care of the increased redundancy in the feature set due to the addition of features, we also propose two efficient schemes for feature selection: the forward selection with trial and error, and the forward selection with criteria of the error probability and the linear correlation coefficients of individual features

Systematization of simplified J-integral evaluation method for flaw evaluation at high temperature

International Nuclear Information System (INIS)

Miura, Naoki; Takahashi, Yukio; Nakayama, Yasunari; Shimakawa, Takashi

2000-01-01

J-integral is an effective inelastic fracture parameter for the flaw evaluation of cracked components at high temperature. The evaluation of J-integral for an arbitrary crack configuration and an arbitrary loading condition can be generally accomplished by detailed numerical analysis such as finite element analysis, however, it is time-consuming and requires a high degree of expertise for its implementation. Therefore, it is important to develop simplified J-integral estimation techniques from the viewpoint of industrial requirements. In this study, a simplified J-integral evaluation method is proposed to estimate two types of J-integral parameters. One is the fatigue J-integral range to describe fatigue crack propagation behavior, and the other is the creep J-integral to describe creep crack propagation behavior. This paper presents the systematization of the simplified J-integral evaluation method incorporated with the reference stress method and the concept of elastic follow-up, and proposes a comprehensive evaluation procedure. The verification of the proposed method is presented in Part II of this paper. (author)

Regulation No. 0-31 on handling of radiation flaw-detectors

International Nuclear Information System (INIS)

1975-01-01

The regulation contains mandatory design, commissioning, and operational requirements for laboratories using flaw-detectors emitting ionizing radiation; also, design, manufacturing, and operational requirements for the production of any type of X-ray or gamma-ray flaw-detectors. Laboratories carrying out non-destructive testing are either stationary or mobile. Conceptual and operating designs are elaborated, including the building and the laboratory lay-outs, the mains, water supply, and sewerage system technological lay-out, explanatory comments, and a lay-out of the shielding equipment. Approbated designs are implemented, and the laboratories commissioned to representatives of the State Sanitary Inspectorate. Licences are issued by the Ministry of Public Health (MPH) and the Committee on Peaceful Uses of Atomic Energy (CPUAE). Any flaw-detector has to conform to the Bulgarian State Standards and be coordinated with the MPH, the CPUAE, and the Central Laboratory for Nuclear Flaw-Detection (CLNFD). The laboratories are required to have operational instructions, an emergency plan, and to keep technological and dosimetric records. The latter are provided and processed by the relevant service at the Research Institute of Radiobiology and Radiation Hygiene. For operations involving of flaw-detectors, presence of at least two workers is required. (G.G.)

Computational reduction of specimen noise to enable improved thermography characterization of flaws in graphite polymer composites

Science.gov (United States)

Winfree, William P.; Howell, Patricia A.; Zalameda, Joseph N.

2014-05-01

Flaw detection and characterization with thermographic techniques in graphite polymer composites are often limited by localized variations in the thermographic response. Variations in properties such as acceptable porosity, fiber volume content and surface polymer thickness result in variations in the thermal response that in general cause significant variations in the initial thermal response. These result in a "noise" floor that increases the difficulty of detecting and characterizing deeper flaws. A method is presented for computationally removing a significant amount of the "noise" from near surface porosity by diffusing the early time response, then subtracting it from subsequent responses. Simulations of the thermal response of a composite are utilized in defining the limitations of the technique. This method for reducing the data is shown to give considerable improvement characterizing both the size and depth of damage. Examples are shown for data acquired on specimens with fabricated delaminations and impact damage.

Computational Reduction of Specimen Noise to Enable Improved Thermography Characterization of Flaws in Graphite Polymer Composites

Science.gov (United States)

Winfree, William P.; Howell, Patricia A.; Zalameda, Joseph N.

2014-01-01

Flaw detection and characterization with thermographic techniques in graphite polymer composites are often limited by localized variations in the thermographic response. Variations in properties such as acceptable porosity, fiber volume content and surface polymer thickness result in variations in the thermal response that in general cause significant variations in the initial thermal response. These result in a "noise" floor that increases the difficulty of detecting and characterizing deeper flaws. A method is presented for computationally removing a significant amount of the "noise" from near surface porosity by diffusing the early time response, then subtracting it from subsequent responses. Simulations of the thermal response of a composite are utilized in defining the limitations of the technique. This method for reducing the data is shown to give considerable improvement characterizing both the size and depth of damage. Examples are shown for data acquired on specimens with fabricated delaminations and impact damage.

Ultrasonic imaging of material flaws exploiting multipath information

Science.gov (United States)

Shen, Xizhong; Zhang, Yimin D.; Demirli, Ramazan; Amin, Moeness G.

2011-05-01

In this paper, we consider ultrasonic imaging for the visualization of flaws in a material. Ultrasonic imaging is a powerful nondestructive testing (NDT) tool which assesses material conditions via the detection, localization, and classification of flaws inside a structure. Multipath exploitations provide extended virtual array apertures and, in turn, enhance imaging capability beyond the limitation of traditional multisensor approaches. We utilize reflections of ultrasonic signals which occur when encountering different media and interior discontinuities. The waveforms observed at the physical as well as virtual sensors yield additional measurements corresponding to different aspect angles. Exploitation of multipath information addresses unique issues observed in ultrasonic imaging. (1) Utilization of physical and virtual sensors significantly extends the array aperture for image enhancement. (2) Multipath signals extend the angle of view of the narrow beamwidth of the ultrasound transducers, allowing improved visibility and array design flexibility. (3) Ultrasonic signals experience difficulty in penetrating a flaw, thus the aspect angle of the observation is limited unless access to other sides is available. The significant extension of the aperture makes it possible to yield flaw observation from multiple aspect angles. We show that data fusion of physical and virtual sensor data significantly improves the detection and localization performance. The effectiveness of the proposed multipath exploitation approach is demonstrated through experimental studies.

Evaluation of flaws in ferritic piping: ASME Code Appendix J, Deformation Plasticity Failure Assessment Diagram (DPFAD)

International Nuclear Information System (INIS)

Bloom, J.M.

1991-08-01

This report summarizes the methods and bases used by an ASME Code procedure for the evaluation of flaws in ferritic piping. The procedure is currently under consideration by the ASME Boiler and Pressure Vessel Code Committee of Section 11. The procedure was initially proposed in 1985 for the evaluation of the acceptability of flaws detected in piping during in-service inspection for certain materials, identified in Article IWB-3640 of the ASME Boiler and Pressure Vessel Code Section 11 ''Rules for In-service Inspection of Nuclear Power Plant Components.'' for which the fracture toughness is not sufficiently high to justify acceptance based solely on the plastic limit load evaluation methodology of Appendix C and IWB-3641. The procedure, referred to as Appendix J, originally included two approaches: a J-integral based tearing instability (J-T) analysis and the deformation plasticity failure assessment diagram (DPFAD) methodology. In Appendix J, a general DPFAD approach was simplified for application to part-through wall flows in ferritic piping through the use of a single DPFAD curve for circumferential flaws. Axial flaws are handled using two DPFAD curves where the ratio of flaw depth to wall thickness is used to determine the appropriate DPFAD curve. Flaws are evaluated in Appendix J by comparing the actual pipe applied stress with the allowable stress with the appropriate safety factors for the flaw size at the end of the evaluation period. Assessment points for circumferential and axial flaws are plotted on the appropriate failure assessment diagram. In addition, this report summarizes the experimental test predictions of the results of the Battelle Columbus Laboratory experiments, the Eiber experiments, and the JAERI tests using the Appendix J DPFAD methodology. Lastly, this report also provides guidelines for handling residual stresses in the evaluation procedure. 22 refs., 13 figs., 5 tabs

Flaw evaluation of Nd:YAG laser welding based plume shape by infrared thermal camera

International Nuclear Information System (INIS)

Kim, Jae Yeol; Yoo, Young Tae; Yang, Dong Jo; Song, Kyung Seol; Ro, Kyoung Bo

2003-01-01

In Nd:YAG laser welding evaluation methods of welding flaw are various. But, the method due to plume shape is difficult to classification od welding flaw. The Nd:YAG laser process is known to have high speed and deep penetration capability to become one of the most advanced welding technologies. At the present time, some methods are studied for measurement of plume shape by using high-speed camera and photo diode. This paper describes the machining characteristics of SM45C carbon steel welding by use of an Nd:YAG laser. In spite of its good mechanical characteristics, SM45C carbon steel has a high carbon contents and suffers a limitation in the industrial application due to the poor welding properties. In this study, plume shape was measured by infrared thermal camera that is non-contact/non-destructive thermal measurement equipment through change of laser generating power, speed, focus. Weld was performed on bead-on method. Measurement results are compared as two equipment. Here, two results are composed of measurement results of plume quantities due to plume shape by infrared thermal camera and inspection results of weld bead include weld flaws by ultrasonic inspector.

Flaw-size measurement in a weld samples by ultrasonic frequency analysis

International Nuclear Information System (INIS)

Adler, L.; Cook, K.V.; Whaley, H.L. Jr.; McClung, R.W.

1975-01-01

An ultrasonic frequency-analysis technique was developed and applies to characterize flaws in an 8-in. (203-mm) thick heavy-section steel weld specimen. The technique applies a multitransducer system. The spectrum of the received broad-band signal is frequency analyzed at two different receivers for each of the flaws. From the two spectra, the size and orientation of the flaw are determined by the use of an analytic model proposed earlier. (auth)

A methodology for determining fabrication flaws in a reactor pressure vessel

International Nuclear Information System (INIS)

Schuster, G.J.; Doctor, S.R.; Simonen, F.A.

1996-01-01

The Pacific Northwest National Laboratory (PNNL) conducted a program with the major objective of estimating the rate of occurrence of fabrication flaws in US light-water reactor pressure vessels (RPVs). In this study, RPV mate4rial was examined using the Synthetic Aperture Focusing Technique for Ultrasonic Testing (SAFT-UT) to detect and characterize flaws created during fabrication. The inspection data obtained in this program has been analyzed to address the rates of flaw occurrence

Radiation flaw detector for testing non-uniform surface bodies of revolution

International Nuclear Information System (INIS)

Valevich, M.I.

1984-01-01

Radiation flaw detector for testing bodies of revolution with non-uniform surface, welded joints, etc., based on spatial filtration and differentiation of ionizing radiation flux has been described. The calculation of the most important unit of flaw detector - integrators - is made. Experimental studies of the sensitivity have shown, that the radiation flaw detector can be used for rapid testing of products with the sensitivity comparable with the sensitivity of radiographic testing of steel

A study on the measurement of flaw sizes by acoustical holography

International Nuclear Information System (INIS)

Yamamoto, M.; Ando, T.; Enami, K.; Yajima, M.; Fukui, S.

1978-01-01

As a means of evaluating the safety of flawed pressure vessels and other structures against fracture, fracture mechanics has come to be applied. For the application of fracture mechanics it is necessary to get information concerning the sizes and shapes of flaws. The ultrasonic flaw detection method which is widely used as a nondestructive inspection method cannot measure the sizes and shapes of flaws accurately. Considering that acoustical holography is an useful means for the measurement of flaws, we performed basic tests on this method and obtained the following results: (1) The measured values of artificial flaws (flat bottom drilled holes: 5 -- 36 mm) made on a steel plate with a thickness of 150 mm showed a good linear relation with their actual sizes and scatter in the measured values was +-3 -- 6 mm. (2) The measured values of fatigue cracks (length: 5 -- 57 mm) introduced into a steel plate with thickness of 150 mm also showed a good linear relation with their actual sizes and scatter in the measured values was +-3 mm. (3) It was found that acoustical holography can also be applied to heavy section cast steels. (4) The method of correcting distortion caused by curved surface was investigated by computer-aided simulation and it was considered that such distortion can be corrected by radial scanning of a transducer. (auth.)

Acoustic emission/flaw relationships for inservice monitoring of LWRs

International Nuclear Information System (INIS)

Hutton, P.H.; Kurtz, R.J.; Friesel, M.A.; Skorpik, J.R.; Dawson, J.F.

1991-10-01

The program concerning Acoustic Emission/Flaw Relationships for Inservice Monitoring of LWRs was initiated in FY76 with the objective of validating the application of acoustic emission (AE) to monitor nuclear reactor pressure-containing components during operation to detect cracking. The program has been supported by the US Nuclear Regulatory Commission, Office of Nuclear Regulatory Research. Research and development has been performed by Pacific Northwest Laboratory, operated for the Department of Energy by Battelle Memorial Institute. The program has shown the feasibility of continuous, on-line AE monitoring to detect crack growth and produced validated methods for applying the technology. Included are relationships for estimating flaw severity from AE data and field applications at Watts Bar Unit 1 Reactor, Limerick Unit 1 Reactor, and the High Flux Isotope Reactor. This report discusses the program scope and organization, the three program phases and the results obtained, standard and code activities, and instrumentation and software developed under this program

Variable flaw shape analysis for a reactor vessel under pressurized thermal shock loading

International Nuclear Information System (INIS)

Yang, C.Y.; Bamford, W.H.

1984-01-01

A study has been conducted to characterize the response of semi-elliptic surface flaws to thermal shock conditions which can result from safety injection actuation in nuclear reactor vessels. A methodology was developed to predict the behavior of a flaw during sample pressurized thermal shock events. The effects of a number of key variables on the flaw propagation were studied, including fracture toughness of the material and its gradient through the thickness, irradiation effects, effects of warm prestressing, and effects of the stainless steel cladding. The results of these studies show that under thermal shock loading conditions the flaw always tends to elongate along the vessel inside surface from the initial aspect ratio. However, the flaw shape always remains finite rather than becoming continuously long, as has often been assumed in earlier analyses. The final shape and size of the flaws were found to be rather strongly dependent on the effects of warm prestressing and the distribution of neutron flux. The improved methodology results in a more accurate and more realistic treatment of flaw shape changes during thermal shock events and provides the potential for quantifying additional margins for reactor vessel integrity analyses

Rotating flux-focusing eddy current probe for flaw detection

Science.gov (United States)

Wincheski, Russell A. (Inventor); Fulton, James P. (Inventor); Nath, Shridhar C. (Inventor); Simpson, John W. (Inventor); Namkung, Min (Inventor)

1997-01-01

A flux-focusing electromagnetic sensor which uses a ferromagnetic flux-focusing lens simplifies inspections and increases detectability of fatigue cracks about circular fasteners and other circular inhomogeneities in high conductivity material. The unique feature of the device is the ferrous shield isolating a high-turn pick-up coil from an excitation coil, The use of the magnetic shield is shown to produce a null voltage output across the receiving coil in the presence of an unflawed sample. A redistribution of the current flow in the sample caused by the presence of flaws, however, eliminates the shielding condition and a large output voltage is produced, yielding a clear unambiguous flaw signal. By rotating the probe in a path around a circular fastener such as a rivet while maintaining a constant distance between the probe and the center of a rivet, the signal due to current flow about the rivet can be held constant. Any further changes in the current distribution, such as due to a fatigue crack at the rivet joint, can be detected as an increase in the output voltage above that due to the flow about the rivet head.

Flaw assessment guide for high-temperature reactor components subject to creep-fatigue loading

International Nuclear Information System (INIS)

Ainsworth, R.A.; Takahashi, Y.

1990-10-01

A high-temperature flaw assessment procedure is described. This procedure is a result of a collaborative effort between Electric Power Research Institute in the United States, Central Research Institute of Electric Power Industry in Japan, and Nuclear Electric plc in the United Kingdom. The procedure addresses preexisting defects subject to creep-fatigue loading conditions. Laws employed to calculate the crack growth per cycle are defined in terms of fracture mechanics parameters and constants related to the component material. The crack-growth laws can be integrated to calculate the remaining life of a component or to predict the amount of crack extension in a given period. Fatigue and creep crack growth per cycle are calculated separately, and the total crack extension is taken as the simple sum of the two contributions. An interaction between the two propagation modes is accounted for in the material properties in the separate calculations. In producing the procedure, limitations of the approach have been identified. 25 refs., 1 fig

Development and application of an LWR reactor pressure vessel-specific flaw distribution

International Nuclear Information System (INIS)

Rosinski, S.T.; Kennedy, E.L.; Foulds, J.R.

1991-01-01

Previous efforts by the US Department of Energy have shown that the PWR reactor vessel integrity predictions performed through probabilistic fracture mechanics analysis for a pressurized thermal shock event are significantly sensitive to the overall flaw distribution input. It has also been shown that modern vessel in-service inspection (ISI) results can be used for development of vessel flaw distribution(s) that are more representative of US vessels. This paper describes the development and application of a methodology to analyze ISI data for the purpose of flaw distribution determination. The resultant methodology considers detection reliability, flaw sizing accuracy, and flaw detection threshold in its application. Application of the methodology was then demonstrated using four recently acquired US PWR vessel inspection data sets. The methodology helped provide original insight into several key inspection performance and vessel integrity prediction practice issues that will impact future vessel integrity evaluation. This paper briefly discusses the development and application of the methodology and the impact to future vessel integrity analyses

Flaw preparations for HSST program vessel fracture mechanics testing: mechanical-cyclic pumping and electron-beam weld-hydrogen-charge cracking schemes

International Nuclear Information System (INIS)

Holz, P.P.

1980-06-01

The purpose of the document is to present schemes for flaw preparations in heavy section steel. The ability of investigators to grow representative sharp cracks of known size, location, and orientation is basic to representative field testing to determine data for potential flaw propagation, fracture behavior, and margin against fracture for high-pressure-, high-temperature-service steel vessels subjected to increasing pressurization and/or thermal shock. Gaging for analytical stress and strain procedures and ultrasonic and acoustic emission instrumentation can then be applied to monitor the vessel during testing and to study crack growth. This report presents flaw preparations for HSST fracture mechanics testing. Cracks were grown by two techniques: (1) a mechanical method wherein a premachined notch was sharpened by pressurization and (2) a method combining electron-beam welds and hydrogen charging to crack the chill zone of a rapidly placed autogenous weld. The mechanical method produces a naturally occurring growth shape controlled primarily by the shape of the machined notch; the welding-electrochemical method produces flaws of uniform depth from the surface of a wall or machined notch. Theories, details, discussions, and procedures are covered for both of the flaw-growing schemes

Stress intensities in flawed pressure vessels

International Nuclear Information System (INIS)

Smith, C.W.; Jolles, M.; Peters, W.H.

1977-01-01

A technique for determining the stess intensity factor (SIF) near pressure vessel flaws or cracks experimentally from photoelastic data for use in two-dimensional problems was developed in the 1950's. This technique was modified and extended to a variety of two-dimensional problems. The technique has been refined further and what has evolved may be regarded as a hybrid technique which affects a marriage between ''frozen stress'' photoelastic results and a simple least-squares digital computer program for estimating SIF values in three-dimensional problems. This technique, in its original modified form, has been shown to be applicable to a study of surface flaws and the applicability of the method to complex crack body geometries of current technological importance are discussed. The analytical foundations of the method are reviewed

Potential change in flaw geometry of an initially shallow finite-length surface flaw during a pressurized-thermal-shock transient

International Nuclear Information System (INIS)

Shum, D.K.; Bryson, J.W.; Merkle, J.G.

1993-09-01

This study presents preliminary estimates on whether an shallow, axially oriented, inner-surface finite-length flaw in a PWR-RPV would tend to elongate in the axial direction and/or deepen into the wall of the vessel during a postulated PTS transient. Analysis results obtained based on the assumptions of (1) linear-elastic material response, and (2) cladding with same toughness as the base metal, indicate that a nearly semicircular flaw would likely propagate in the axial direction followed by propagation into the wall of the vessel. Note that these results correspond to initiation within the lower-shelf fracture toughness temperature range, and that their general validity within the lower-transition temperature range remains to be determined. The sensitivity of the numerical results aid conclusions to the following analysis assumptions are evaluated: (1) reference flaw geometry along the entire crack front and especially within the cladding region; (2) linear-elastic vs elastic-plastic description of material response; and (3) base-material-only vs bimaterial cladding-base vessel-model assumption. The sensitivity evaluation indicates that the analysis results are very sensitive to the above assumptions

Fracture evaluation of an in-service piping flaw caused by microbiologically induced corrosion

International Nuclear Information System (INIS)

Rudland, D.L.; Scott, P.M.; Wilkowski, G.M.; Rahman, S.

1996-01-01

A pipe fracture experiment was conducted on a section of 6-inch nominal diameter pipe which was degraded by microbiologically induced corrosion (MIC) at a circumferential girth weld. The pipe was a section of one of the service water piping systems to one of the emergency diesel generators at the Haddam Neck (Connecticut Yankee) plant. The experimental results will help validate future ASME Section XI pipe flaw evaluation criteria for other than Class 1 piping. A critical aspect of this experiment was an assessment of the degree of conservatism embodied in the ASME definition of flaw size. The ASME flaw size definition assumes a rectangular shaped, constant depth flaw with a depth equal to its maximum depth for its entire length. Since most service flaws are irregular in shape, this definition may be overly conservative. Results from several fracture prediction models are compared with the experimental results. These results show that, for this case, the ASME Appendix H criteria significantly underpredicted the experimental maximum moment, while other fracture prediction models provided good predictions when accurate pipe, weld and flaw dimensions were used

Estimation of the number of physical flaws from periodic ISI data of SG tubes using effective POD

International Nuclear Information System (INIS)

Lee, Jae Bong; Park, Jai Hak; Kim, Hong Deok; Chung, Han Sub

2008-01-01

It is necessary to know the number of flaws and their size distribution in order to calculate the probability of failure or to estimate the amount of leakage through the tube wall of steam generators. But In-Service Inspection (ISI) flaw data is different from the physical flaw data. In case of a single inspection, it is easy to estimate the number of physical flaws using the POD curve. However, we may be faced with some difficulties in obtaining the number of physical flaws from the periodic in-service inspection data. In this study a method for estimating the number of physical flaws from periodic in-service inspection data is proposed. In order to calculate the number of physical flaws with periodic ISI data, both probabilities of detecting and missing flaws should be considered. And flaw initiation and growth history must be known also. The flaw initiation and growth history can be inferred from appropriate probabilistic flaw growth rate. Two inference methods are proposed and compared. One is Monte Carlo simulation method and the other is transition (stochastic) matrix method. The effective POD, the total possibility of detection considering both probabilities of detecting and missing flaws for each flaw size, can be calculated using above two inference methods. And two methods are compared and the usefulness and convenience are evaluated from several applications

Method for the detection of flaws in a tube proximate a contiguous member

International Nuclear Information System (INIS)

Holt, A.E.; Wehrmeister, A.E.; Whaley, H.L.

1979-01-01

A method for deriving the eddy current signature of a flaw in a tube proximate a contiguous member which is obscured in a composite signature of the flaw and contiguous member comprises subtracting from the composite signature a reference eddy current signature generated by scanning a reference or facsimile tube and contiguous member. The method is particularly applicable to detecting flaws in the tubes of heat exchangers of fossil fuel and nuclear power plants to enable the detection of flaws which would otherwise be obscured by contiguous members such as support plates supporting the tubes. (U.K.)

Self-esteem and communal responsiveness toward a flawed partner: the fair-weather care of low-self-esteem individuals.

Science.gov (United States)

Lemay, Edward P; Clark, Margaret S

2009-06-01

Three studies provide evidence that people with low self-esteem, but not those with high self-esteem, distance themselves from a flawed partner in situations in which the flaws seem likely to reflect negatively on them. Participants with low (but not high) self-esteem reduced their motivation to care for the partner's needs when they felt they might share a partner's salient flaws (Study 1), when they were primed to focus on similarities between themselves and a socially devalued partner (Study 2), and when they learned that their partner was socially incompetent (Study 3). In Study 3, individuals with low (but not high) self-esteem provided less emotional support and experienced more public image threat when they learned that partners were socially incompetent. In addition, all three studies provided evidence that participants' distancing reduced their confidence in the partner's motivation to care for them, suggesting that distancing involves a cost to the self.

MANAGING HIGH-END, HIGH-VOLUME INNOVATIVE PRODUCTS

Directory of Open Access Journals (Sweden)

Gembong Baskoro

2008-01-01

Full Text Available This paper discuses the concept of managing high-end, high-volume innovative products. High-end, high-volume consumer products are products that have considerable influence to the way of life. Characteristic of High-end, high-volume consumer products are (1 short cycle time, (2 quick obsolete time, and (3 rapid price erosion. Beside the disadvantages that they are high risk for manufacturers, if manufacturers are able to understand precisely the consumer needs then they have the potential benefit or success to be the market leader. High innovation implies to high utilization of the user, therefore these products can influence indirectly to the way of people life. The objective of managing them is to achieve sustainability of the products development and innovation. This paper observes the behavior of these products in companies operated in high-end, high-volume consumer product.

Design flaw could delay collider

CERN Multimedia

Cho, Adrian

2007-01-01

"A magnet for the Large Hadron Collider (LHC) failed during a key test at the European particle physics laboratory CERN last week. Physicists and engineers will have to repair the damaged magnet and retrofit others to correct the underlynig design flaw, which could delay the start-up of the mammouth subterranean machine." (1,5 page)

Tearing stability analysis of an axial surface flaw in thick-walled pressure vessels

International Nuclear Information System (INIS)

Zahoor, A.; Ghassemi, B.B.

1991-01-01

This paper presents two fracture mechanics models for evaluation of an axial surface flaw in pressure vessels. The surface flaw is located on the outside surface of the vessel. The first model assumes yielding of the remaining ligament directly ahead of the flaw. The second model assumes contained yielding ahead of the flaw and uses a linear elastic fracture mechanics solution. The former model is suitable for cases where the combination of material toughness, flaw size, and load is such that initiation of flaw growth follows ligament yielding. The latter model is suitable for low-toughness materials where initiation of crack growth and potential tearing instability may occur prior to the yielding of the ligament. Both models are suitable for thick-walled vessels. The paper discusses the applicability regime for both models. The models are then applied to a test vessel and the predicted failure pressure is compared against the pressure attained in the test. Results show that both models can be applied successfully. In particular, the contained yielding model when used with the plane-stress assumption can give reasonable predictions even for cases that involve yielding of the ligament. (orig.)

Tearing stability analysis of an axial surface flaw in thick-walled pressure vessels

Energy Technology Data Exchange (ETDEWEB)

Zahoor, A.; Ghassemi, B.B. (NOVETECH Corp., Rockville, MD (USA))

1991-04-01

This paper presents two fracture mechanics models for evaluation of an axial surface flaw in pressure vessels. The surface flaw is located on the outside surface of the vessel. The first model assumes yielding of the remaining ligament directly ahead of the flaw. The second model assumes contained yielding ahead of the flaw and uses a linear elastic fracture mechanics solution. The former model is suitable for cases where the combination of material toughness, flaw size, and load is such that initiation of flaw growth follows ligament yielding. The latter model is suitable for low-toughness materials where initiation of crack growth and potential tearing instability may occur prior to the yielding of the ligament. Both models are suitable for thick-walled vessels. The paper discusses the applicability regime for both models. The models are then applied to a test vessel and the predicted failure pressure is compared against the pressure attained in the test. Results show that both models can be applied successfully. In particular, the contained yielding model when used with the plane-stress assumption can give reasonable predictions even for cases that involve yielding of the ligament. (orig.).

Probabilistic assessment of critically flawed LMFBR PHTS piping elbows

International Nuclear Information System (INIS)

Balkey, K.R.; Wallace, I.T.; Vaurio, J.K.

1982-01-01

One of the important functions of the Primary Heat Transport System (PHTS) of a large Liquid Metal Fast Breeder Reactor (LMFBR) plant is to contain the circulating radioactive sodium in components and piping routed through inerted areas within the containment building. A significant possible failure mode of this vital system is the development of cracks in the piping components. This paper presents results from the probabilistic assessment of postulated flaws in the most-critical piping elbow of each piping leg. The criticality of calculated maximum sized flaws is assessed against an estimated material fracture toughness to determine safety factors and failure probability estimates using stress-strength interference theory. Subsequently, a different approach is also employed in which the randomness of the initial flaw size and loading are more-rigorously taken into account. This latter approach yields much smaller probability of failure values when compared to the stress-strength interference analysis results

Fundamentally Flawed: Extension Administrative Practice (Part 1).

Science.gov (United States)

Patterson, Thomas F., Jr.

1997-01-01

Extension's current administrative techniques are based on the assumptions of classical management from the early 20th century. They are fundamentally flawed and inappropriate for the contemporary workplace. (SK)

Biaxial loading and shallow-flaw effects on crack-tip constraint and fracture-toughness

International Nuclear Information System (INIS)

Pennell, W.E.; Bass, B.R.; Bryson, J.W.; McAfee, W.J.; Theiss, T.J.; Rao, M.C.

1993-01-01

Uniaxial tests of single-edged notched bend (SENB) specimens with both deep- and shallow-flaws have shown elevated fracture-toughness for the shallow flaws. The elevation in fracture-toughness for shallow flaws has been shown to be the result of reduced constraint at the crack-tip. Biaxial loading has the potential to increase constraint at the crack-tip and thereby reduce some of the shallow-flaw, fracture-toughness elevation. Biaxial fracture-toughness tests have shown that the shallow-flaw, fracture-toughness elevation is reduced but not eliminated by biaxial loading. Dual-parameter, fracture-toughness correlations have been proposed to reflect the effect of crack-tip constraint on fracture-toughness. Test results from the uniaxial and biaxial tests were analyzed using the dual-parameter technology. Discrepancies between analysis results and cleavage initiation site data from fractographic examinations indicate that the analysis models are in need of further refinement. Addition of a precleavage, ductile-tearing element to the analysis model has the potential to resolve the noted discrepancies

Calculation and evaluation methodology of the flawed pipe and the compute program development

International Nuclear Information System (INIS)

Liu Chang; Qian Hao; Yao Weida; Liang Xingyun

2013-01-01

Background: The crack will grow gradually under alternating load for a pressurized pipe, whereas the load is less than the fatigue strength limit. Purpose: Both calculation and evaluation methodology for a flawed pipe that have been detected during in-service inspection is elaborated here base on the Elastic Plastic Fracture Mechanics (EPFM) criteria. Methods: In the compute, the depth and length interaction of a flaw has been considered and a compute program is developed per Visual C++. Results: The fluctuating load of the Reactor Coolant System transients, the initial flaw shape, the initial flaw orientation are all accounted here. Conclusions: The calculation and evaluation methodology here is an important basis for continue working or not. (authors)

Experimental verification on limit load estimation method for pipes with an arbitrary shaped circumferential surface flaw

International Nuclear Information System (INIS)

Li, Yinsheng; Hasegawa, Kunio; Miura, Naoki; Hoshino, Katsuaki

2010-01-01

When a flaw is detected in stainless steel pipes during in-service inspection, the limit load criterion given in the codes such as JSME Rules on Fitness-for-Service for Nuclear Power Plants or ASME Boiler and Pressure Vessel Code Section XI can be applied to evaluate the integrity of the pipe. However, in these codes, the limit load criterion is only provided for pipes containing a flaw with uniform depth, although many flaws with complicated shape such as stress corrosion cracking have been actually detected in pipes. In order to evaluate the integrity of the flawed pipes for general case, a limit load estimation method has been proposed by authors considering a circumferential surface flaw with arbitrary shape. The plastic collapse bending moment and corresponding stress are obtained by dividing the surface flaw into several segmented sub-flaws. In this paper, the proposed method was verified by comparing with experimental results. Four-point bending experiments were carried out for full scale stainless steel pipes with a symmetrical or non-symmetrical circumferential flaw. Estimated failure bending moments by the proposed method were found to be in good agreement with the experimental results, and the proposed method was confirmed to be effective for evaluating bending failure of pipes with flaw. (author)

Finite-element analysis of flawed and unflawed pipe tests

International Nuclear Information System (INIS)

James, R.J.; Nickell, R.E.; Sullaway, M.F.

1989-12-01

Contemporary versions of the general purpose, nonlinear finite element program ABAQUS have been used in structural response verification exercises on flawed and unflawed austenitic stainless steel and ferritic steel piping. Among the topics examined, through comparison between ABAQUS calculations and test results, were: (1) the effect of using variations in the stress-strain relationship from the test article material on the calculated response; (2) the convergence properties of various finite element representations of the pipe geometry, using shell, beam and continuum models; (3) the effect of test system compliance; and (4) the validity of ABAQUS J-integral routines for flawed pipe evaluations. The study was culminated by the development and demonstration of a ''macroelement'' representation for the flawed pipe section. The macroelement can be inserted into an existing piping system model, in order to accurately treat the crack-opening and crack-closing static and dynamic response. 11 refs., 20 figs., 1 tab

Stress-induced light scattering method for the detection of latent flaws on fine polished glass substrates.

Science.gov (United States)

Sakata, Y; Sakai, K; Nonaka, K

2014-08-01

Fine polishing techniques, such as the chemical mechanical polishing treatment, are one of the most important technique to glass substrate manufacturing. Mechanical interaction in the form of friction occurs between the abrasive and the substrate surface during polishing, which may cause formation of latent flaws on the glass substrate surface. Fine polishing-induced latent flaws may become obvious during a subsequent cleaning process if glass surfaces are corroded away by chemical interaction with the cleaning liquid. Latent flaws thus reduce product yield. In general, non-destructive inspection techniques, such as the light-scattering methods, used to detect foreign matters on the glass substrate surface. However, it is difficult to detect latent flaws by these methods because the flaws remain closed. Authors propose a novel inspection technique for fine polishing-induced latent flaws by combining the light scattering method with stress effects, referred to as the stress-induced light scattering method (SILSM). SILSM is able to distinguish between latent flaws and particles on the surface. In this method, samples are deformed by an actuator and stress effects are induced around the tips of latent flaws. Due to the photoelastic effect, the refractive index of the material around the tip of a latent flaw is changed. This changed refractive index is in turn detected by a cooled charge-coupled device camera as variations in light scattering intensity. In this report, surface latent flaws are detected non-destructively by applying SILSM to glass substrates, and the utility of SILSM evaluated as a novel inspection technique.

Detecting accuracy of flaws by manual and automatic ultrasonic inspections

International Nuclear Information System (INIS)

Iida, K.

1988-01-01

As the final stage work in the nine year project on proving tests of the ultrasonic inspection technique applied to the ISI of LWR plants, automatic ultrasonic inspection tests were carried out on EDM notches, surface fatigue cracks, weld defects and stress corrosion cracks, which were deliberately introduced in full size structural components simulating a 1,100 MWe BWR. Investigated items are the performance of a newly assembled automatic inspection apparatus, detection limit of flaws, detection resolution of adjacent collinear or parallel EDM notches, detection reproducibility and detection accuracy. The manual ultrasonic inspection of the same flaws as inspected by the automatic ultrasonic inspection was also carried out in order to have comparative data. This paper reports how it was confirmed that the automatic ultrasonic inspection is much superior to the manual inspection in the flaw detection rate and in the detection reproducibility

Flaw characterization through nonlinear ultrasonics and wavelet cross-correlation algorithms

Science.gov (United States)

Bunget, Gheorghe; Yee, Andrew; Stewart, Dylan; Rogers, James; Henley, Stanley; Bugg, Chris; Cline, John; Webster, Matthew; Farinholt, Kevin; Friedersdorf, Fritz

2018-04-01

Ultrasonic measurements have become increasingly important non-destructive techniques to characterize flaws found within various in-service industrial components. The prediction of remaining useful life based on fracture analysis depends on the accurate estimation of flaw size and orientation. However, amplitude-based ultrasonic measurements are not able to estimate the plastic zones that exist ahead of crack tips. Estimating the size of the plastic zone is an advantage since some flaws may propagate faster than others. This paper presents a wavelet cross-correlation (WCC) algorithm that was applied to nonlinear analysis of ultrasonically guided waves (GW). By using this algorithm, harmonics present in the waveforms were extracted and nonlinearity parameters were used to indicate both the tip of the cracks and size of the plastic zone. B-scans performed with the quadratic nonlinearities were sensitive to micro-damage specific to plastic zones.

Behavior of deep flaws in a thick-wall cylinder under thermal shock loading

International Nuclear Information System (INIS)

Cheverton, R.D.

1979-01-01

Behavior of inner-surface flaws in thick-walled vessels was studied in a 991-mm OD x 152 mm wall x 1220 mm length cylinder with toughness properties similar to those for HSST Plate. The initial temperature of 93 0 C and a thermal shock medium of liquid nitrogen (-197 0 C) were employed. The initial flaw selected was a sharp, 16 mm deep, long (1220 mm) axial crack. Crack arrest methodology was shown to be valid for deep flaws under severe thermal shock

AE/flaw characterization for nuclear pressure vessels

International Nuclear Information System (INIS)

Hutton, P.H.; Kurtz, R.J.; Pappas, R.A.

1984-01-01

This chapter discusses the use of acoustic emission (AE) detected during continuous monitoring to identify and evaluate growing flaws in pressure vessels. Off-reactor testing and on-reactor testing are considered. Relationships for identifying acoustic emission (AE) from crack growth and using the AE data to estimate flaw severity have been developed experimentally by laboratory testing. The purpose of the off-reactor vessel test is to evaluate AE monitoring/interpretation methodology on a heavy section steel vessel under simulated reactor operating conditions. The purpose of on-reactor testing is to evaluate the capability of a monitor system to function in the reactor environment, calibrate the ability to detect AE signals, and to demonstrate that a meaningful criteria can be established to prevent false alarms. An expanded data base is needed from application testing and methodology standardization

Development of a shallow-flaw fracture assessment methodology for nuclear reactor pressure vessels

International Nuclear Information System (INIS)

Bass, B.R.; Bryson, J.W.; Dickson, T.L.; McAfee, W.J.; Pennell, W.E.

1996-01-01

Shallow-flaw fracture technology is being developed within the Heavy-Section Steel Technology (HSST) Program for application to the safety assessment of radiation-embrittled nuclear reactor pressure vessels (RPVs) containing postulated shallow flaws. Cleavage fracture in shallow-flaw cruciform beam specimens tested under biaxial loading at temperatures in the lower transition temperature range was shown to be strain-controlled. A strain-based dual-parameter fracture toughness correlation was developed and shown to be capable of predicting the effect of crack-tip constraint on fracture toughness for strain-controlled fracture. A probabilistic fracture mechanics (PFM) model that includes both the properties of the inner-surface stainless-steel cladding and a biaxial shallow-flaw fracture toughness correlation gave a reduction in probability of cleavage initiation of more than two orders of magnitude from an ASME-based reference case

Detection and Characterization of Flaws in Sprayed on Foam Insulation with Pulsed Terahertz Frequency Electromagnetic Waves

Science.gov (United States)

Winfree, William P.; Madaras, Eric I.

2005-01-01

The detection and repair of flaws such as voids and delaminations in the sprayed on foam insulation of the external tank reduces the probability of foam debris during shuttle ascent. The low density of sprayed on foam insulation along with it other physical properties makes detection of flaws difficult with conventional techniques. An emerging technology that has application for quantitative evaluation of flaws in the foam is pulsed electromagnetic waves at terahertz frequencies. The short wavelengths of these terahertz pulses make them ideal for imaging flaws in the foam. This paper examines the application of terahertz pulses for flaw detection in foam characteristic of the foam insulation of the external tank. Of particular interest is the detection of voids and delaminations, encapsulated in the foam or at the interface between the foam and a metal backing. The technique is shown to be capable of imaging small voids and delaminations through as much as 20 cm of foam. Methods for reducing the temporal responses of the terahertz pulses to improve flaw detection and yield quantitative characterizations of the size and location of the flaws are discussed.

Arc-discharge system for nondestructive detection of flaws in thin ceramic coatings

International Nuclear Information System (INIS)

Scott, G.W.; Davis, E.V.

1978-04-01

The feasibility of nondestructively detecting small cracks or holes in plasma-sprayed ceramic coatings with an electric arc-discharge system was studied. We inspected ZrO 2 coatings 0.46 mm (0.018 in.) thick on Incoloy alloy 800 substrates. Cracks were artificially induced in controlled areas of the specimens by straining the substrates in tension. We designed and built a system to scan the specimen's surface at approximately 50 μm (0.002 in.) clearance with a sharp-pointed metal-tipped probe at high dc potential. The system measures the arc currents occurring at flaws, or plots a map of the scanned area showing points where the arc current exceeds a preset threshold. A theoretical model of the probe-specimen circuit shows constant dc potential to be the best choice for arc-discharge inspection of insulating coatings. Experimental observations and analysis of the data disclosed some potential for flaw description

Determination of Flaw Size and Depth From Temporal Evolution of Thermal Response

Science.gov (United States)

Winfree, William P.; Zalameda, Joseph N.; Cramer, Elliott; Howell, Patricia A.

2015-01-01

Simple methods for reducing the pulsed thermographic responses of flaws have tended to be based on either the spatial or temporal response. This independent assessment limits the accuracy of characterization. A variational approach is presented for reducing the thermographic data to produce an estimated size for a flaw that incorporates both the temporal and spatial response to improve the characterization. The size and depth are determined from both the temporal and spatial thermal response of the exterior surface above a flaw and constraints on the length of the contour surrounding the delamination. Examples of the application of the technique to simulation and experimental data acquired are presented to investigate the limitations of the technique.

Probabilistic Fracture Mechanics of Reactor Pressure Vessels with Populations of Flaws

Energy Technology Data Exchange (ETDEWEB)

Spencer, Benjamin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Backman, Marie [Univ. of Tennessee, Knoxville, TN (United States); Williams, Paul [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hoffman, William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Alfonsi, Andrea [Idaho National Lab. (INL), Idaho Falls, ID (United States); Dickson, Terry [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bass, B. Richard [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Klasky, Hilda [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-09-01

This report documents recent progress in developing a tool that uses the Grizzly and RAVEN codes to perform probabilistic fracture mechanics analyses of reactor pressure vessels in light water reactor nuclear power plants. The Grizzly code is being developed with the goal of creating a general tool that can be applied to study a variety of degradation mechanisms in nuclear power plant components. Because of the central role of the reactor pressure vessel (RPV) in a nuclear power plant, particular emphasis is being placed on developing capabilities to model fracture in embrittled RPVs to aid in the process surrounding decision making relating to life extension of existing plants. A typical RPV contains a large population of pre-existing flaws introduced during the manufacturing process. The use of probabilistic techniques is necessary to assess the likelihood of crack initiation at one or more of these flaws during a transient event. This report documents development and initial testing of a capability to perform probabilistic fracture mechanics of large populations of flaws in RPVs using reduced order models to compute fracture parameters. The work documented here builds on prior efforts to perform probabilistic analyses of a single flaw with uncertain parameters, as well as earlier work to develop deterministic capabilities to model the thermo-mechanical response of the RPV under transient events, and compute fracture mechanics parameters at locations of pre-defined flaws. The capabilities developed as part of this work provide a foundation for future work, which will develop a platform that provides the flexibility needed to consider scenarios that cannot be addressed with the tools used in current practice.

Simulating the x-ray image contrast to setup techniques with desired flaw detectability

Science.gov (United States)

Koshti, Ajay M.

2015-04-01

The paper provides simulation data of previous work by the author in developing a model for estimating detectability of crack-like flaws in radiography. The methodology is developed to help in implementation of NASA Special x-ray radiography qualification, but is generically applicable to radiography. The paper describes a method for characterizing the detector resolution. Applicability of ASTM E 2737 resolution requirements to the model are also discussed. The paper describes a model for simulating the detector resolution. A computer calculator application, discussed here, also performs predicted contrast and signal-to-noise ratio calculations. Results of various simulation runs in calculating x-ray flaw size parameter and image contrast for varying input parameters such as crack depth, crack width, part thickness, x-ray angle, part-to-detector distance, part-to-source distance, source sizes, and detector sensitivity and resolution are given as 3D surfaces. These results demonstrate effect of the input parameters on the flaw size parameter and the simulated image contrast of the crack. These simulations demonstrate utility of the flaw size parameter model in setting up x-ray techniques that provide desired flaw detectability in radiography. The method is applicable to film radiography, computed radiography, and digital radiography.

Detecting flaws in welds

International Nuclear Information System (INIS)

Woodacre, A.; Lawton, H.

1979-01-01

An apparatus and a method for detecting flaws in welds in a workpiece, the portion of the workpiece containing the weld is maintained at a constant temperature and the weld is scanned by an infra red detector. The weld is then scanned again with the workpiece in contact with a cooling probe to produce a steeper temperature gradient across the weld. Comparison of the signals produced by each scan reveals the existence of defects in the welds. The signals may be displayed on an oscilloscope and the display may be observed by a TV camera and recorded on videotape. (UK)

Origin and type of flaws in heat engine ceramic materials and components

International Nuclear Information System (INIS)

Govila, R.K.

1995-01-01

A number of ceramic materials such as Silicon Nitrides and Carbides, Sialons, Whisker-Reinforced Ceramic Composites and Partially-Stabilized Zirconias (PSZs) have been developed for use as structural components in heat engine applications. The reliability and durability of a structural engine component is critically dependent on the size, density of distribution and location of flaws. This information is critical for the processing and design engineers in order to design structural components using suitable materials and thus minimize stress intensity. In general, the failure initiating flaws are associated or produced due to material impurity, processing methods and parameters, and fabrication techniques (machining and grinding). Examples of each type of flaws associated with material impurity, processing methods and fabrication techniques are illustrated

Flux-focusing eddy current probe and rotating probe method for flaw detection

Science.gov (United States)

Wincheski, Buzz A.; Fulton, James P.; Nath, Shridhar C.; Simpson, John W.; Namkung, Min

1994-11-01

A flux-focusing electromagnetic sensor which uses a ferromagnetic flux-focusing lens simplifies inspections and increases detectability of fatigue cracks about circular fasteners and other circular inhomogeneities in high conductivity material. The unique feature of the device is the ferrous shield isolating a high-turn pick-up coil from an excitation coil. The use of the magnetic shield is shown to produce a null voltage output across the receiving coil in the presence of an unflawed sample. A redistribution of the current flow in the sample caused by the presence of flaws, however, eliminates the shielding condition and a large output voltage is produced, yielding a clear unambiguous flaw signal. By rotating the probe in a path around a circular fastener such as a rivet while maintaining a constant distance between the probe and the center of a rivet, the signal due to current flow about the rivet can be held constant. Any further changes in the current distribution, such as due to a fatigue crack at the rivet joint, can be detected as an increase in the output voltage above that due to the flow about the rivet head.

Analytical solution for stress, strain and plastic instability of pressurized pipes with volumetric flaws

International Nuclear Information System (INIS)

Cunha, Sérgio B.; Netto, Theodoro A.

2012-01-01

The mechanical behavior of internally pressurized pipes with volumetric flaws is analyzed. The two possible modes of circumferentially straining the pipe wall are identified and associated to hypothesized geometries. The radial deformation that takes place by bending the pipe wall is studied by means of axisymmetric flaws and the membrane strain developed by unequal hoop deformation is analyzed with the help of narrow axial flaws. Linear elastic shell solutions for stress and strain are developed, the plastic behavior is studied and the maximum hoop stress at the flaw is related to the undamaged pipe hoop stress by means of stress concentration factors. The stress concentration factors are employed to obtain equations predicting the pressure at which the pipe fails by plastic instability for both types of flaw. These analytical solutions are validated by comparison with burst tests on 3″ diameter pipes and finite element simulations. Forty-one burst tests were carried out and two materials with very dissimilar plastic behavior, carbon steel and austenitic stainless steel, were used in the experiments. Both the analytical and the numerical predictions showed good correlation with the experimentally observed burst pressures. - Highlights: ► An analytical model for the burst of a pipe with a volumetric flaw is developed. ► Deformation, strain and stress are modeled in the elastic and plastic domains. ► The model is comprehensively validated by experiments and numerical simulations. ► The burst pressure model’s accuracy is equivalent to finite element simulations.

Development of technology on natural flaw fabrication and precise diagnosis for the major components in NPPs

International Nuclear Information System (INIS)

Han, Jung Ho; Choi, Myung Sik; Lee, Doek Hyun; Hur, Do Haeng

2002-01-01

The objective of this research is to develop a fabrication technology of natural flaw specimen of major components in NPPs and a technology of precise diagnosis for failure and degradation of components using natural flaw specimen. 1) Successful development of the natural flaw fabrication technology of SG tube 2) Evaluation of ECT signal and development of precise diagnosis using natural flaws. - Determination of length, depth, width, and multiplicity of fabricated natural flaws. - Informations about detectability and accuracy of ECT evaluation on various kinds of defects are collected when the combination of probe and frequency is changed. - An advanced technology for precise ECT evaluation is established. 3) Application of precise ECT diagnosis to failure analysis of SG tube in operation. - Fretting wear of KSNP SG. - ODSCC at tube expanded region of KSNP SG. - Determination of through/non-through wall of axial crack

Experimental study on flaw detectability of remote field eddy current testing

International Nuclear Information System (INIS)

Kamimura, T.; Fukui, S.; Iwahashi, Y.; Yamada, H.

1988-01-01

For the purpose of comprehending the effect in practical use of the remote field eddy current (RFEC) testing that becomes noticeable for the ISI technique of steel tubes, its flaw detectability was clarified through a model test. This study used straight and bending tubes of 3.8 mm in wall thickness and 31.8 mm in outside diameter. These tubes were inspected from their inside. After relations among the pickup coil output, coil distance, testing frequency, etc. were measured, a probe of the practical use type was manufactured to investigate its flaw detectability by means of simulated flaws. The authors discuss how it has been found that light local wall thinning on the outside surfaces can be detected by this technique and its effect in practical use can be expected with small influences due to magnetic permeability variations of tube materials, bending of tubes, etc

Crack propagation from a filled flaw in rocks considering the infill influences

Science.gov (United States)

Chang, Xu; Deng, Yan; Li, Zhenhua; Wang, Shuren; Tang, C. A.

2018-05-01

This study presents a numerical and experimental study of the cracking behaviour of rock specimen containing a single filled flaw under compression. The primary aim is to investigate the influences of infill on crack patterns, load-displacement response and specimen strength. The numerical code RFPA2D (Rock Failure Process Analysis) featured by the capability of modeling heterogeneous materials is employed to develop the numerical model, which is further calibrated by physical tests. The results indicate that there exists a critical infill strength which controls crack patterns for a given flaw inclination angle. For case of infill strength lower than the critical value, the secondary or anti-cracks are disappeared by increasing the infill strength. If the infill strength is greater than the critical value, the filled flaw has little influence on the cracking path and the specimen fails by an inclined crack, as if there is no flaw. The load-displacement responses show specimen stiffness increases by increasing infill strength until the infill strength reaches its critical value. The specimen strength increases by increasing the infill strength and almost keeps constant as the infill strength exceeds its critical value.

Time-dependent leak behavior of flawed Alloy 600 tube specimens at constant pressure

Energy Technology Data Exchange (ETDEWEB)

Bahn, Chi Bum, E-mail: bahn@anl.gov [Argonne National Laboratory, Argonne, IL 60439 (United States); Majumdar, Saurin [Argonne National Laboratory, Argonne, IL 60439 (United States); Harris, Charles [United States Nuclear Regulatory Commission, Rockville, MD 20852 (United States)

2011-10-15

Leak rate testing has been performed using Alloy 600 tube specimens with throughwall flaws. Some specimens have shown time-dependent leak behavior at constant pressure conditions. Fractographic characterization was performed to identify the time-dependent crack growth mechanism. The fracture surface of the specimens showed the typical features of ductile fracture, as well as the distinct crystallographic facets, typical of fatigue crack growth at low {Delta}K level. Structural vibration appears to have been caused by the oscillation of pressure, induced by a high-pressure pump used in a test facility, and by the water jet/tube structure interaction. Analyses of the leak behaviors and crack growth indicated that both the high-pressure pump and the water jet could significantly contribute to fatigue crack growth. To determine whether the fatigue crack growth during the leak testing can occur solely by the water jet effect, leak rate tests at constant pressure without the high-pressure pump need to be performed. - Highlights: > Leak rate of flawed Alloy 600 tubing increased at constant pressure condition. > Fractography revealed two cases: ductile tearing and crystallographic facets. > Crystallographic facets are typical features of fatigue crack growth at low {Delta}K. > Fatigue source could be water jet-induced vibration and/or high-pressure pump pulsation.

Proposal of limit moment equation applicable to planar/non-planar flaw in wall thinned pipes under bending

International Nuclear Information System (INIS)

Tsuji, Masataka; Meshii, Toshiyuki

2011-01-01

Highlights: → A limit moment equation applicable to planar/non-planar flaw of 0 ≤ θ ≤ π found in wall thinned straight pipes was proposed. → An idea to rationally classify planar/non-planar flaw in wall thinned pipes was proposed. → The equation based on the experimental observation focused on the fracture mode. - Abstract: In this paper, a limit bending moment equation applicable to all types of planar and non-planar flaws in wall-thinned straight pipes under bending was proposed. A system to rationally classify the planar/non-planar flaws in wall-thinned pipes was suggested based on experimental observations focused on the fracture mode. The results demonstrate the importance of distinguishing between axial and circumferential long flaws in wall-thinned pipes.

A study on the development of a real-time intelligent system for ultrasonic flaw classification

International Nuclear Information System (INIS)

Song, Sung Jin; Kim, Hak Joon; Lee, Hyun; Lee, Seung Seok

1998-01-01

In spite of significant progress in research on ultrasonic pattern recognition it is not widely used in many practical field inspection in weldments. For the convenience of field application of this methodology, following four key issues have to be suitably addressed; 1) a software where the ultrasonic pattern recognition algorithm is efficiently implemented, 2) a real-time ultrasonic testing system which can capture the digitized ultrasonic flaw signal so the pattern recognition software can be applied in a real-time fashion, 3) database of ultrasonic flaw signals in weldments, which is served as a foundation of the ultrasonic pattern recognition algorithm, and finally, 4) ultrasonic features which should be invariant to operational variables of the ultrasonic test system. Presented here is the recent progress in the development of a real-time ultrasonic flaw classification by the novel combination of followings; an intelligent software for ultrasonic flaw classification in weldments, a computer-base real-time ultrasonic nondestructive evaluation system, database of ultrasonic flaw signals, and invariant ultrasonic features called 'normalized features.'

Analytical solution for stress, strain and plastic instability of pressurized pipes with volumetric flaws

Energy Technology Data Exchange (ETDEWEB)

Cunha, Sergio B., E-mail: sbcunha@petrobras.com.br [PETROBRAS/TRANSPETRO, Av. Pres. Vargas 328 - 7th floor, Rio de Janeiro, RJ 20091-060 (Brazil); Netto, Theodoro A., E-mail: tanetto@lts.coppe.ufrj.br [COPPE, Federal University ot Rio de Janeiro, Ocean Engineering Department, PO BOX 68508, Rio de Janeiro - RJ (Brazil)

2012-01-15

The mechanical behavior of internally pressurized pipes with volumetric flaws is analyzed. The two possible modes of circumferentially straining the pipe wall are identified and associated to hypothesized geometries. The radial deformation that takes place by bending the pipe wall is studied by means of axisymmetric flaws and the membrane strain developed by unequal hoop deformation is analyzed with the help of narrow axial flaws. Linear elastic shell solutions for stress and strain are developed, the plastic behavior is studied and the maximum hoop stress at the flaw is related to the undamaged pipe hoop stress by means of stress concentration factors. The stress concentration factors are employed to obtain equations predicting the pressure at which the pipe fails by plastic instability for both types of flaw. These analytical solutions are validated by comparison with burst tests on 3 Double-Prime diameter pipes and finite element simulations. Forty-one burst tests were carried out and two materials with very dissimilar plastic behavior, carbon steel and austenitic stainless steel, were used in the experiments. Both the analytical and the numerical predictions showed good correlation with the experimentally observed burst pressures. - Highlights: Black-Right-Pointing-Pointer An analytical model for the burst of a pipe with a volumetric flaw is developed. Black-Right-Pointing-Pointer Deformation, strain and stress are modeled in the elastic and plastic domains. Black-Right-Pointing-Pointer The model is comprehensively validated by experiments and numerical simulations. Black-Right-Pointing-Pointer The burst pressure model's accuracy is equivalent to finite element simulations.

Probabilistic assessment of flaw evaluation procedures for pressure vessel integrity

International Nuclear Information System (INIS)

Shaffer, D.H.; Bamford, W.H.; Jouris, G.M.

1980-01-01

Prudent design procedures, in order to err in the direction of conservative over-strength rather than risky under-strength, have taken bounding values rather than best estimates for material parameters, and wherever possible, used conservative input for the calculations. The growing data base for this work is now beginning to allow an assessment of the conservatism that has been incorporated into the design procedure. Quantitative estimates of the variability associated with crack growth rates and fracture toughness have been generated in connection with other studies, and it would be useful to incorporate such information into an overall assessment of the design margins that are prescribed. In addition to getting an estimate of the conservatism in the current procedure, this study should provide a useful insight into the relative degree of margin that is introduced at each stage of the flaw evaluation process. Identification of the step by step margins should lead to more effective data collection programs from which information for adequately controlling the design conservatism can be obtained. The study will also provide valuable guidance in fixing revised design reference curves and safety factors so that adequate overall margins can be maintained without excess conservatism. This study is limited to vessel rupture in a brittle mode, and examples for illustration are particularly related to the beltline region of a reactor pressure vessel. The methodology, however, is applicable to all regions for which the required stress analyses, operating history, and material parameters are available. The work being carried out here is in consonance with ASME Section XI on Flaw Evaluation Procedures. It is concerned both with flaws under normal operating conditions and flaws under faulted conditions. (author)

Methods and means of the radioisotope flaw detection of the nuclear power reactors components

International Nuclear Information System (INIS)

Dekopov, A.S.; Majorov, A.N.; Firsov, V.G.

1979-01-01

Methods and means are considered for the radioisotopic flaw detection of the nuclear reactors pressure vessels and structural components of the reactor circuit. Methods of control are described as in the technological process of fabrication of the power reactors assemblies as during the systematic-preventive repair of the nuclear power station equipment during exploitation. Methodological base is given of the technology of radiation control of welded joints of the pressure vessel branch piper of the WWER-440 and WWER-1000 reactors in the process of assembling and exploitation and joining pipes with the pipe-plate of the steamgenerator in the process of fabrication. Methods of the radioisotope flaw detection in the process of exploitation take into consideration the influence of the radioisotope background, and ensure obtaining of the demanded by the rules of control, sensitivity. Methods of control of welded joints of the steamgenerator of nuclear power plants are based on the simultaneous examination of all joints with application of the shaped radiographic plate-holders. Special gamma-flaw-detection equipment is developed for control of the welded joints of the main branch-pipes. Design peculiarities are given of the installation for flaw detection. These installations are equipped with the system for emergency return of the radiation source into the storage position from the position for exposure. They have automatic exposure-meters for determination of the exposure time. Successfull exploitation of such installations in the Finland during assembling equipment for the nuclear reactor of the nuclear power plant ''Loviisa-1'' and in the USSR on the Novovoronezh nuclear power plant has shown possibility for detection of flaws having dimensions about 1% of the equipment used. For control of welded joints of pipes with pipe-plates at the steam generators, portable flaw-detectors are used. Sensitivity of these flaw-detectors towards detection of the wire standards has

On flaw tolerance of nacre: a theoretical study

Science.gov (United States)

Shao, Yue; Zhao, Hong-Ping; Feng, Xi-Qiao

2014-01-01

As a natural composite, nacre has an elegant staggered ‘brick-and-mortar’ microstructure consisting of mineral platelets glued by organic macromolecules, which endows the material with superior mechanical properties to achieve its biological functions. In this paper, a microstructure-based crack-bridging model is employed to investigate how the strength of nacre is affected by pre-existing structural defects. Our analysis demonstrates that owing to its special microstructure and the toughening effect of platelets, nacre has a superior flaw-tolerance feature. The maximal crack size that does not evidently reduce the tensile strength of nacre is up to tens of micrometres, about three orders higher than that of pure aragonite. Through dimensional analysis, a non-dimensional parameter is proposed to quantify the flaw-tolerance ability of nacreous materials in a wide range of structural parameters. This study provides us some inspirations for optimal design of advanced biomimetic composites. PMID:24402917

Internal Rot Detection with the Use of Low-Frequency Flaw Detector

Science.gov (United States)

Proskórnicki, Marek; Ligus, Grzegorz

2014-12-01

The issue of rot detection in standing timber or stocked wood is very important in forest management. Rot flaw detection used for that purpose is represented by invasive and non-invasive devices. Non-invasive devices are very accurate, but due to the cost and complicated operation they have not been applied on a large scale in forest management. Taking into account the practical needs of foresters a prototype of low-frequency flaw was developed. The principle of its operation is based on the difference in acoustic wave propagation in sound wood and wood with rot.

Measurement of flaw size in a weld sample by ultrasonic frequency analysis

International Nuclear Information System (INIS)

Whaley, H.L. Jr.; Adler, L.; Cook, K.V.; McClung, R.W.

1975-05-01

An ultrasonic frequency analysis technique has been developed and applied to the measurement of flaws in an 8-in.-thick heavy-section steel specimen belonging to the Pressure Vessel Research Committee program. Using the technique the flaws occurring in the weld area were characterized in quantitative terms of both dimension and orientation. Several modifications of the technique were made during the study to include the application of several transducers and to consider ultrasonic mode conversion. (U.S.)

Characterization of flaws in a tube bundle mock-up for reliability studies

International Nuclear Information System (INIS)

Kupperman, D.S.; Bakhtiari, S.

1997-01-01

As part of an assessment of in-service inspection of steam generator tubes, the authors will assemble a steam generator mock-up for round robin studies and use as a test bed in evaluating emerging technologies. Progress is reported on the characterization of flaws that will be part of the mock-up. Eddy current and ultrasonic techniques are being evaluated as a means to characterize the flaws in the mock-up tubes before final assembly. Twenty Inconel 600 tubes with laboratory-grown cracks, typical of those to be used in the mock-up, were provided by Pacific Northwest National Laboratory for laboratory testing. After the tubes were inspected with eddy current and ultrasonic techniques, they were destructively analyzed to establish the actual depths, lengths, and profiles of the cracks. The analysis of the results will allow the best techniques to be used for characterizing the flaws in the mock-up tubes

Characterization of flaws in a tube bundle mock-up for reliability studies

International Nuclear Information System (INIS)

Kupperman, D.S.; Bakhtiari, S.

1996-10-01

As part of an assessment of in-service inspection of steam generator tubes, the authors will assemble a steam generator mock-up for round robin studies and use as a test bed in evaluating emerging technologies. Progress is reported on the characterization of flaws that will be part of the mock-up. Eddy current and ultrasonic techniques are being evaluated as a means to characterize the flaws in the mock-up tubes before final assembly. Twenty Inconel 600 tubes with laboratory-grown cracks, typical of those to be used in the mock-up, were provided by Pacific Northwest National Laboratory for laboratory testing. After the tubes were inspected with eddy current and ultrasonic techniques, they were destructively analyzed to establish the actual depths, lengths, and profiles of the cracks. The analysis of the results will allow the best techniques to be used for characterizing the flaws in the mock-up tubes

Detector-device-independent quantum secret sharing with source flaws.

Science.gov (United States)

Yang, Xiuqing; Wei, Kejin; Ma, Haiqiang; Liu, Hongwei; Yin, Zhenqiang; Cao, Zhu; Wu, Lingan

2018-04-10

Measurement-device-independent entanglement witness (MDI-EW) plays an important role for detecting entanglement with untrusted measurement device. We present a double blinding-attack on a quantum secret sharing (QSS) protocol based on GHZ state. Using the MDI-EW method, we propose a QSS protocol against all detector side-channels. We allow source flaws in practical QSS system, so that Charlie can securely distribute a key between the two agents Alice and Bob over long distances. Our protocol provides condition on the extracted key rate for the secret against both external eavesdropper and arbitrary dishonest participants. A tight bound for collective attacks can provide good bounds on the practical QSS with source flaws. Then we show through numerical simulations that using single-photon source a secure QSS over 136 km can be achieved.

China’s Flawed Banking Market Structure Must be Rectified

Institute of Scientific and Technical Information of China (English)

于永臻

2007-01-01

There is great disparity between China’s banking management efficiency and the top international standard,with relatively low efficiency in credit monetary allocation.In this paper,Yu Yongzhen sets out the hypothesis that"medium-sized banks promote competition".He believes that an important reason for the low efficiency of Chinese banking is the seriously flawed banking market structure.Namely,credit market shares are highly concentrated in the hands of the four major state-owned banks,with very few shares held by medium-sized banks or the badly undeveloped small banks.Full development of medium-sized banks plays a key role in the promotion of competition and efficiency in banking.

A robust indicator based on singular value decomposition for flaw feature detection from noisy ultrasonic signals

Science.gov (United States)

Cui, Ximing; Wang, Zhe; Kang, Yihua; Pu, Haiming; Deng, Zhiyang

2018-05-01

Singular value decomposition (SVD) has been proven to be an effective de-noising tool for flaw echo signal feature detection in ultrasonic non-destructive evaluation (NDE). However, the uncertainty in the arbitrary manner of the selection of an effective singular value weakens the robustness of this technique. Improper selection of effective singular values will lead to bad performance of SVD de-noising. What is more, the computational complexity of SVD is too large for it to be applied in real-time applications. In this paper, to eliminate the uncertainty in SVD de-noising, a novel flaw indicator, named the maximum singular value indicator (MSI), based on short-time SVD (STSVD), is proposed for flaw feature detection from a measured signal in ultrasonic NDE. In this technique, the measured signal is first truncated into overlapping short-time data segments to put feature information of a transient flaw echo signal in local field, and then the MSI can be obtained from the SVD of each short-time data segment. Research shows that this indicator can clearly indicate the location of ultrasonic flaw signals, and the computational complexity of this STSVD-based indicator is significantly reduced with the algorithm proposed in this paper. Both simulation and experiments show that this technique is very efficient for real-time application in flaw detection from noisy data.

Imaging flaws in thin metal plates using a magneto-optic device

Science.gov (United States)

Wincheski, B.; Prabhu, D. R.; Namkung, M.; Birt, E. A.

1992-01-01

An account is given of the capabilities of the magnetooptic/eddy-current imager (MEI) apparatus in the case of aging aircraft structure-type flaws in 2024-T3 Al alloy plates. Attention is given to images of cyclically grown fatigue cracks from rivetted joints in fabricated lap-joint structures, electrical discharge machining notches, and corrosion spots. Although conventional eddy-current methods could have been used, the speed and ease of MEI's use in these tests is unmatched by such means. Results are displayed in real time as a test piece is scanned, furnishing easily interpreted flaw images.

Derivation of Elastic Stress Concentration Factor Equations for Debris Fretting Flaws in Pressure Tubes of Pressurized Heavy Water Reactors

International Nuclear Information System (INIS)

Kim, Jong Sung; Oh, Young Jin

2014-01-01

If volumetric flaws such as bearing pad fretting flaws and debris fretting flaws are detected in the pressure tubes of pressurized heavy water reactors during in-service inspection, the initiation of fatigue cracks and delayed hydrogen cracking from the detected volumetric flaws shall be assessed by using elastic stress concentration factors in accordance with CSA N285.8-05. The CSA N285.8-05 presents only an approximate formula based on linear elastic fracture mechanics for the debris fretting flaw. In this study, an engineering formula considering the geometric characteristics of the debris fretting flaw in detail was derived using two-dimensional finite element analysis and Kinectrics, Inc.'s engineering procedure with slight modifications. Comparing the application results obtained using the derived formula with the three-dimensional finite element analysis results, it is found that the results obtained using the derived formula agree well with the results of the finite element analysis

A study on the extraction of feature variables for the pattern recognition for welding flaws

International Nuclear Information System (INIS)

Kim, J. Y.; Kim, C. H.; Kim, B. H.

1996-01-01

In this study, the researches classifying the artificial and natural flaws in welding parts are performed using the pattern recognition technology. For this purpose the signal pattern recognition package including the user defined function was developed and the total procedure including the digital signal processing, feature extraction, feature selection and classifier selection is treated by bulk. Specially it is composed with and discussed using the statistical classifier such as the linear discriminant function classifier, the empirical Bayesian classifier. Also, the pattern recognition technology is applied to classification problem of natural flaw(i.e multiple classification problem-crack, lack of penetration, lack of fusion, porosity, and slag inclusion, the planar and volumetric flaw classification problem). According to this results, if appropriately teamed the neural network classifier is better than stastical classifier in the classification problem of natural flaw. And it is possible to acquire the recognition rate of 80% above through it is different a little according to domain extracting the feature and the classifier.

Analysis of Weld Fabrication Flaws in High-Level Radioactive Waste Disposal Containers: Experiences from the US Programme

International Nuclear Information System (INIS)

Bullen, Daniel; Apted, Mick

2002-11-01

The purpose of this report is to examine key issues regarding the fabrication, closure and defect detection in canisters for radioactive waste disposal in a deep geological repository. As a preliminary step, a review is made of the closure-weld design and non-destructive evaluation (NDE) of the closure seal for the US high-level waste repository programme. This includes statistical analysis of the data obtained by NDE and identification of key areas of investigation where additional data are required. Information from other industrial experiences on closure and flaw detection of metal containers is also reviewed. The canister material and closure methods for the US programme and industrial activities reviewed here differ from those of SKB's KBS-3 reference design. The issues and approaches to issue resolution identified from the US programme and industrial analogues, however, can provide an initial basis for preparing for independent review of SKB's canister closure plans and encapsulation facility

Influence of circumferential flaw length on internal burst pressure of a wall-thinned pipe

Energy Technology Data Exchange (ETDEWEB)

Tsuji, Masataka, E-mail: tsuji-m@u-fukui.ac.jp [Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui, Fukui (Japan); Meshii, Toshiyuki [Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui, Fukui (Japan)

2013-02-15

Highlights: ► The effect of θ on p{sub f} was examined by experimental analysis and FEA. ► Here θ is the circumferential angle of a flaw, p{sub f} is the internal burst pressure. ► p{sub f} decreased as θ increased in some cases. ► The effect of θ on p{sub f} should be taken into consideration in evaluating p{sub f}. -- Abstract: This paper examines the effect of the circumferential angle of a flaw θ on the internal burst pressure p{sub f} of pipes with artificial wall-thinned flaws. The effect of θ has conventionally been regarded as unimportant in the evaluation of the p{sub f} of wall-thinned straight pipes. Therefore, a burst pressure equation for an axial crack inside a cylinder (Fig. 1, left), such as Kiefner's equation (Kiefner et al., 1973), has been widely applied (ANSI/ASME B31.G., 1991; Hasegawa et al., 2011). However, the following implicit assumptions notably exist when applying the equation to planar flaws in situations with non-planar flaws. 1)The fracture mode of the non-planar flaw under consideration is identical to that of the crack. 2)The effect of θ on p{sub f}, which is not considered for an axial crack, is small or negligible. However, the experimental results from the systematic burst tests for carbon steel pipes with artificial wall-thinned flaws examined in this paper showed that these implicit assumptions may be incorrect. In this paper the experimental results are evaluated in further detail. The purpose of the evaluation was to clarify the effect of θ on p{sub f}. Specifically, the significance of the flaw configuration (axial length δ{sub z} and wall-thinning ratio t{sub 1}/t) was studied for its effects on θ and p{sub f}. In addition, a simulation of this effect was conducted using a large strain elastic-plastic Finite Element Analysis (FEA) model. As observed from the experimental results, θ tended to affect p{sub f} in cases with large δ{sub z}, and t{sub 1}/t was also correlated with a decrease in p{sub f

Characterization of type, position and dimension of flaws by transit time locus curves of ultrasonic inspections - ALOK. Pt. 2

International Nuclear Information System (INIS)

Grohs, B.; Barbian, O.A.; Kappes, W.; Paul, H.

1981-01-01

With automatic ultrasonic testing, flaws can be detected and described and thus characterized according to their type, position and dimensions. During scanning of a test object, the flaws are registered by many different pathways and many different acoustic irradiation directions. The transit time locus curve represents the distance between the relfecting points of a flaw and the source in dependence of the probe position; hence, information on flaw position and dimensions can be derived from this curve. If the sound velocity is known, the transit path can then be calculated from the transit time. This requires, above all, a constant sound velocity along the whole transit path. Various methods are presented for reconstructing the flaw border in the plane of incidence. (orig./RW) [de

Textual and language flaws: problems for Spanish doctors in producing abstracts in English

Directory of Open Access Journals (Sweden)

Lourdes Divasson Cilveti

2006-04-01

Full Text Available Scientific journals are the primary source of information for researchers. The number of articles currently indexed in databases is so large that it has become almost impossible to read every relevant article in a particular field. Thus, research paper abstracts (RPAs have acquired increasing importance. Several studies have shown that they are the skipping point, particularly among non-native English speakers. To our knowledge, little research has been carried out on RPA writing by Spanish doctors. It is thus the objective of this article to analyse the way abstracts are structured and linguistically realized by these professionals. We selected 30 RPAs written in English by Spanish speaking doctors from three leading Spanish journals on internal medicine. We recorded their textual level flaws by measuring the degree of informativeness with regard to three main variables: move patterning, ordering and structuring, and their language use flaws under two broad categories: ortho-typographic and grammatical. Length, use of hedges and keywords were also identified. 86.6% of the abstracts were informative, 13.3% uninformative while none of them could be classified as highly informative. With regard to the authors' use of language, over 70% presented some kind of flaws: 21.55% of these mistakes were ortho-typographic while 78.44% were grammatical. Our results support the need of designing specific units geared on the one hand towards explicit teaching of structured abstracts and on the other, towards the difficulties found by doctors because they lack language competence. They would also benefit from clearer guidelines from journal editors.

FDAAA legislation is working, but methodological flaws undermine the reliability of clinical trials: a cross-sectional study

Directory of Open Access Journals (Sweden)

Douglas H. Marin dos Santos

2015-06-01

Full Text Available The relationship between clinical research and the pharmaceutical industry has placed clinical trials in jeopardy. According to the medical literature, more than 70% of clinical trials are industry-funded. Many of these trials remain unpublished or have methodological flaws that distort their results. In 2007, it was signed into law the Food and Drug Administration Amendments Act (FDAAA, aiming to provide publicly access to a broad range of biomedical information to be made available on the platform ClinicalTrials (available at https://www.clinicaltrials.gov. We accessed ClinicalTrials.gov and evaluated the compliance of researchers and sponsors with the FDAAA. Our sample comprised 243 protocols of clinical trials of biological monoclonal antibodies (mAb adalimumab, bevacizumab, infliximab, rituximab, and trastuzumab. We demonstrate that the new legislation has positively affected transparency patterns in clinical research, through a significant increase in publication and online reporting rates after the enactment of the law. Poorly designed trials, however, remain a challenge to be overcome, due to a high prevalence of methodological flaws. These flaws affect the quality of clinical information available, breaching ethical duties of sponsors and researchers, as well as the human right to health.

FDAAA legislation is working, but methodological flaws undermine the reliability of clinical trials: a cross-sectional study.

Science.gov (United States)

Marin Dos Santos, Douglas H; Atallah, Álvaro N

2015-01-01

The relationship between clinical research and the pharmaceutical industry has placed clinical trials in jeopardy. According to the medical literature, more than 70% of clinical trials are industry-funded. Many of these trials remain unpublished or have methodological flaws that distort their results. In 2007, it was signed into law the Food and Drug Administration Amendments Act (FDAAA), aiming to provide publicly access to a broad range of biomedical information to be made available on the platform ClinicalTrials (available at https://www.clinicaltrials.gov). We accessed ClinicalTrials.gov and evaluated the compliance of researchers and sponsors with the FDAAA. Our sample comprised 243 protocols of clinical trials of biological monoclonal antibodies (mAb) adalimumab, bevacizumab, infliximab, rituximab, and trastuzumab. We demonstrate that the new legislation has positively affected transparency patterns in clinical research, through a significant increase in publication and online reporting rates after the enactment of the law. Poorly designed trials, however, remain a challenge to be overcome, due to a high prevalence of methodological flaws. These flaws affect the quality of clinical information available, breaching ethical duties of sponsors and researchers, as well as the human right to health.

Evaluation of J-integral estimation scheme for flawed throughwall pipes

Energy Technology Data Exchange (ETDEWEB)

Zahoor, A.

1987-02-01

The accuracy of the EPRI J-integral estimation scheme for pipes with throughwall cracks and subjected to pure bending was assessed using available experimental data on circumferentially flawed throughwall pipes. The evaluations were performed using elastic plastic J-integral (J) and tearing modulus (T) analysis methods. The results indicated that the EPRI J estimation scheme solutions are unnecessarily conservative compared to results from pipe experiments. As a result of these evaluations an improved J estimation scheme is developed, which is shown to have improved accuracy compared to the original EPRI J estimation scheme. These results imply that the flaw evaluation procedures in the ASME Code on austenitic piping welds are conservative. These results also have applications to the leak before break fracture mechanics analyses.

Evaluation of J-integral estimation scheme for flawed throughwall pipes

International Nuclear Information System (INIS)

Zahoor, A.

1987-01-01

The accuracy of the EPRI J-integral estimation scheme for pipes with throughwall cracks and subjected to pure bending was assessed using available experimental data on circumferentially flawed throughwall pipes. The evaluations were performed using elastic plastic J-integral (J) and tearing modulus (T) analysis methods. The results indicated that the EPRI J estimation scheme solutions are unnecessarily conservative compared to results from pipe experiments. As a result of these evaluations an improved J estimation scheme is developed, which is shown to have improved accuracy compared to the original EPRI J estimation scheme. These results imply that the flaw evaluation procedures in the ASME Code on austenitic piping welds are conservative. These results also have applications to the leak before break fracture mechanics analyses. (orig.)

Detection of plane, poorly oriented wide flaws using focused transducers

International Nuclear Information System (INIS)

Vadder, D. de; Azou, P.; Bastien, P.; Saglio, R.

1976-01-01

The detection of plane, poorly oriented, wide flaws by ultrasonic non destructive testing is distinctly improved when using focused transducers. An increased echo can be obtained crossing the defect limit [fr

Probabilistic calibration of safety coefficients for flawed components in nuclear engineering

International Nuclear Information System (INIS)

Ardillon, E.; Pitner, P.; Barthelet, B.; Remond, A.

1996-01-01

The rules that are currently under application to verify the acceptance of flaws in nuclear components rely on deterministic criteria supposed to ensure the safe operating of plants. The interest of having a precise and reliable method to evaluate the safety margins and the integrity of components led Electricite de France to launch an approach to link directly safety coefficients with safety levels. This paper presents a probabilistic methodology to calibrate safety coefficients in relation to reliability target values. The proposed calibration procedure applies to the case of a ferritic flawed pipe using the R6 procedure for assessing the integrity of the structure. (authors). 5 refs., 5 figs

Probabilistic calibration of safety coefficients for flawed components in nuclear engineering

International Nuclear Information System (INIS)

Ardillon, E.; Pitner, P.; Barthelet, B.; Remond, A.

1995-01-01

The current rules applied to verify the flaws acceptance in nuclear components rely on deterministic criteria supposed to ensure the plant safe operation. The interest in have a precise and reliable method to evaluate the safety margins and the integrity of components led Electricite de France to launch an approach to link directly safety coefficients with safety levels. This paper presents a probabilistic methodology to calibrate safety coefficients in relation do reliability target values. The proposed calibration procedure applies to the case of a ferritic flawed pipe using the R 6 procedure for assessing the structure integrity. (author). 5 refs., 5 figs., 1 tab

CLEAVAGE FRACTURE ANALYSIS OF CLADDED BEAMS WITH AN EMBEDDED FLAW UNDER FOUR-POINT BENDING

International Nuclear Information System (INIS)

Yin, Shengjun; Williams, Paul T; Bass, Bennett Richard

2008-01-01

Semi-large scale embedded flaw beams were tested at Nuclear Research Institute (NRI) Rez in the Czech Republic for the 6th Network for Evaluating Structural Components (NESC-VI) project. The experiments included, among others, a series of semi-large scale tests on cladded beam specimens containing simulated sub-clad flaws. Oak Ridge National Laboratory (ORNL) conducted numerical studies to analyze the constraint issues associated with embedded flaws using various fracture mechanics methods, including T-Stress, hydrostatic stress based QH stress, and the Weibull stress model. The recently developed local approach using the modified Weibull stress model combined with the Master Curve methodology was also utilized to predict the failure probability (Pf) of semi-large scale beams. For this study, the Weibull statistical model associated with the Master Curve methodology was employed to stochastically simulate the fracture toughness data using the available Master Curve reference temperature T0 for the tested base material from the 'aged' WWER-440 Reactor Pressure Vessel (RPV). The study was also conducted to investigate the sensitivity of predicated probability of failure of semi-large scale beams with embedded flaw with different Weibull shape parameters, m

Vitamin D and depression: a systematic review and meta-analysis comparing studies with and without biological flaws.

Science.gov (United States)

Spedding, Simon

2014-04-11

Efficacy of Vitamin D supplements in depression is controversial, awaiting further literature analysis. Biological flaws in primary studies is a possible reason meta-analyses of Vitamin D have failed to demonstrate efficacy. This systematic review and meta-analysis of Vitamin D and depression compared studies with and without biological flaws. The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The literature search was undertaken through four databases for randomized controlled trials (RCTs). Studies were critically appraised for methodological quality and biological flaws, in relation to the hypothesis and study design. Meta-analyses were performed for studies according to the presence of biological flaws. The 15 RCTs identified provide a more comprehensive evidence-base than previous systematic reviews; methodological quality of studies was generally good and methodology was diverse. A meta-analysis of all studies without flaws demonstrated a statistically significant improvement in depression with Vitamin D supplements (+0.78 CI +0.24, +1.27). Studies with biological flaws were mainly inconclusive, with the meta-analysis demonstrating a statistically significant worsening in depression by taking Vitamin D supplements (-1.1 CI -0.7, -1.5). Vitamin D supplementation (≥800 I.U. daily) was somewhat favorable in the management of depression in studies that demonstrate a change in vitamin levels, and the effect size was comparable to that of anti-depressant medication.

Fracture assessment of shallow-flaw cruciform beams tested under uniaxial and biaxial loading conditions

International Nuclear Information System (INIS)

Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

1999-01-01

A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow, surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a far-field, out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for an RPV material. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies, namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness; the conventional maximum principal stress criterion indicated no effect. A three-parameter Weibull model based on the hydrostatic stress criterion is shown to correlate with the experimentally observed biaxial effect on cleavage fracture toughness by providing a scaling mechanism between uniaxial and biaxial loading states. (orig.)

Detecting and Preventing Type flaws at Static Time

DEFF Research Database (Denmark)

Bodei, Chiara; Brodo, Linda; Degano, Pierpaolo

2010-01-01

A type flaw attack on a security protocol is an attack where an honest principal is cheated on interpreting a field in a message as the one with a type other than the intended one. In this paper, we shall present an extension of the LYSA calculus to cope with types, by using tags to represent...

Reconstructing flaw image using dataset of full matrix capture technique

Energy Technology Data Exchange (ETDEWEB)

Lee, Tae Hun; Kim, Yong Sik; Lee, Jeong Seok [KHNP Central Research Institute, Daejeon (Korea, Republic of)

2017-02-15

A conventional phased array ultrasonic system offers the ability to steer an ultrasonic beam by applying independent time delays of individual elements in the array and produce an ultrasonic image. In contrast, full matrix capture (FMC) is a data acquisition process that collects a complete matrix of A-scans from every possible independent transmit-receive combination in a phased array transducer and makes it possible to reconstruct various images that cannot be produced by conventional phased array with the post processing as well as images equivalent to a conventional phased array image. In this paper, a basic algorithm based on the LLL mode total focusing method (TFM) that can image crack type flaws is described. And this technique was applied to reconstruct flaw images from the FMC dataset obtained from the experiments and ultrasonic simulation.

An corrective method to correct of the inherent flaw of the asynchronization direct counting circuit

International Nuclear Information System (INIS)

Wang Renfei; Liu Congzhan; Jin Yongjie; Zhang Zhi; Li Yanguo

2003-01-01

As a inherent flaw of the Asynchronization Direct Counting Circuit, the crosstalk, which is resulted from the randomicity of the time-signal always exists between two adjacent channels. In order to reduce the counting error derived from the crosstalk, the author propose an effective method to correct the flaw after analysing the mechanism of the crosstalk

Effect of combined loading due to bending and internal pressure on pipe flaw evaluation criteria

International Nuclear Information System (INIS)

Miura, Naoki; Sakai, Shinsuke

2006-01-01

Considering a rational maintenance rule of Light Water Reactor piping, reliable flaw evaluation criteria are essential to determine how a detected flaw is detrimental to continuous plant operation. Ductile fracture is one of the dominant failure modes to be considered for carbon steel piping, and can be analyzed by the elastic-plastic fracture mechanics. Some analytical efforts have been provided as flaw evaluation criteria using load correction factors such like the Z-factors in the JSME codes on fitness-for-service for nuclear power plants or the ASME boiler and pressure vessel code section XI. The present correction factors were conventionally determined taken conservatism and simplicity into account, however, the effect of internal pressure which would be an important factor under an actual plant condition was not adequately considered. Recently, a J-estimation scheme, 'LBB. ENGC' for ductile fracture analysis of circumferentially through-wall-cracked pipes subjected combined loading was newly developed to have a better prediction with more realistic manner. This method is explicitly incorporated the contribution of both bending and tension due to internal pressure by means of the scheme compatible with an arbitrary combined loading history. In this paper, the effect of internal pressure on the flaw evaluation criteria was investigated using the new J-estimation scheme. A correction factor based on the new J-estimation scheme was compared with the present correction factors, and the predictability of the current flaw evaluation criteria was quantitatively evaluated in consideration of internal pressure. (author)

Flaw evaluation of thermally aged cast stainless steel in light-water reactor applications

International Nuclear Information System (INIS)

Lee, S.; Kuo, P.T.; Wichman, K.; Chopra, O.

1997-01-01

Cast stainless steel may be used in the fabrication of the primary loop piping, fittings, valve bodies, and pump casings in light-water reactors. However, this material is subject to embrittlement due to thermal aging at the reactor temperature, that is 290 o C (550 o F). The Argonne National Laboratory (ANL) recently completed a research program and the results indicate that the lower-bound fracture toughness of thermally aged cast stainless steel is similar to that of submerged arc welds (SAWs). Thus, the US Nuclear Regulatory Commission (NRC) staff has accepted the use of SAW flaw evaluation procedures in IWB-3640 of Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code to evaluate flaws in thermally aged cast stainless steel for a license renewal evaluation. Alternatively, utilities may estimate component-specific fracture toughness of thermally aged cast stainless steel using procedures developed at ANL for a case-by-case flaw evaluation. (Author)

Gamma flaw detectors for radiographic control of welded joint quality under mounting conditions

International Nuclear Information System (INIS)

Khoroshev, V.N.; Galash, T.F.; Andreev, V.L.; Grigor'ev, V.M.; Medvedev, N.E.

1978-01-01

Main characteristics are presented of gamma flaw detector models used for radiographic control of the quality of welded steel and pipeline joints during assembly. Specially developed experimental models, operating with 75 Se, 90 Sr, 170 Tm, 137 Cs and 192 Ir sources are considered. The new instruments have been made on a single structural base, which creates a foundation for standardizing individual units of radiation heads, manual control panels, containers, exterior packings, devices and accessories, maintenance techniques, and repair techniques. They are distinguished by small sizes and weight, possibility of using a set of radiation sources ensuring control of 3-40 mm thick joints, and reliable protection. Special devices permit to reduce 2-3-folds the time needed for installing and orienting the flaw detectors. The expected economic effect from implementation of the new gamma flaw detectors into industry will amount to 1.5-10.0 thousand roubles per annum for one detector at approximate cost of each detector equal to 3.5-6.0 thousand roubles

The influence of long-range residual stress on plastic collapse of pressurised pipes with and without flaws

International Nuclear Information System (INIS)

Wu, Gui-Yi; Smith, David J.; Pavier, Martyn J.

2013-01-01

Structural integrity assessments of pressurised pipes include plastic collapse as a potential failure mode. This paper uses analytical and numerical models to explore the effect of the end conditions of the pipe on the collapse pressure. The pipe is open-ended and two bounding conditions are addressed: one where axial loading is applied to the ends of the pipe and the other where a fixed axial displacement is applied. The fixed axial displacement condition represents long-range or fit-up residual stress. It is common practice to treat long-range residual stress in the same way as axial loading, leading to the conclusion that such long-range residual stress reduces the collapse pressure. Pipes in a number of states are considered: pipes with no flaws, pipes with fully circumferential flaws and pipes with part circumferential flaws. The flaws consist of either a crack or a slot on the external surface of the pipe. For the axial load condition, the collapse pressure for a flawed pipe is reduced when higher magnitudes of tensile or compressive axial loads are applied. For the fixed displacement condition however, the magnitude of the displacement may have little or no effect on the collapse pressure. The results of the work indicate that substantially conservative assessments may be made of the collapse pressures of pipes containing flaws, when long-range residual stress is taken to be a form of axial loading. -- Highlights: • The effect of end conditions on the collapse pressure of a pipe has been explored. • Fixed displacement conditions represent long-range residual stress. • Long-range residual stress is commonly thought to contribute to plastic collapse. • We show long-range residual stress has no influence on collapse for flawed pipes. • It is therefore possible to reduce conservatism in structural integrity assessment

Vitamin D and Depression: A Systematic Review and Meta-Analysis Comparing Studies with and without Biological Flaws

Directory of Open Access Journals (Sweden)

Simon Spedding

2014-04-01

Full Text Available Efficacy of Vitamin D supplements in depression is controversial, awaiting further literature analysis. Biological flaws in primary studies is a possible reason meta-analyses of Vitamin D have failed to demonstrate efficacy. This systematic review and meta-analysis of Vitamin D and depression compared studies with and without biological flaws. The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA guidelines. The literature search was undertaken through four databases for randomized controlled trials (RCTs. Studies were critically appraised for methodological quality and biological flaws, in relation to the hypothesis and study design. Meta-analyses were performed for studies according to the presence of biological flaws. The 15 RCTs identified provide a more comprehensive evidence-base than previous systematic reviews; methodological quality of studies was generally good and methodology was diverse. A meta-analysis of all studies without flaws demonstrated a statistically significant improvement in depression with Vitamin D supplements (+0.78 CI +0.24, +1.27. Studies with biological flaws were mainly inconclusive, with the meta-analysis demonstrating a statistically significant worsening in depression by taking Vitamin D supplements (−1.1 CI −0.7, −1.5. Vitamin D supplementation (≥800 I.U. daily was somewhat favorable in the management of depression in studies that demonstrate a change in vitamin levels, and the effect size was comparable to that of anti-depressant medication.

Detecting and revising flaws in OWL object property expressions

CSIR Research Space (South Africa)

Keet, CM

2012-10-01

Full Text Available to the ontologist's intention. However, the more one can do, the higher the chance modelling flaws are introduced; hence, an unexpected or undesired classification or inconsistency may actually be due to a mistake in the object property box, not the class axioms. We...

Potential steam generator tube rupture in the presence of severe accident thermal challenge and tube flaws due to foreign object wear

International Nuclear Information System (INIS)

Liao, Y.; Guentay, S.

2009-01-01

This study develops a methodology to assess the probability for the degraded PWR steam generator to rupture first in the reactor coolant pressure boundary, under severe accident conditions with counter-current natural circulating high temperature gas in the hot leg and SG tubes. The considered SG tube flaws are caused by foreign object wear, which in recent years has emerged as a major inservice degradation mechanism for the new generation tubing materials. The first step develops the statistical distributions for the flaw frequency, size, and the flaw location with respect to the tube length and the tube's tubesheet position, based on data of hundreds of flaws reported in numerous SG inservice inspection reports. The next step performs thermal-hydraulic analysis using the MELCOR code and recent CFD findings to predict the thermal challenge to the degraded tubes and the tube-to-tube difference in thermal response at the SG entrance. The final step applies the creep rupture models in the Monte Carlo random walk to test the potential for the degraded SG to rupture before the surge line. The mean and range of the SG tube rupture probability can be applied to estimate large early release frequency in probabilistic safety assessment.

Evaluating empirical/analytical techniques to predict structural integrity of pipe containing surface flaws

International Nuclear Information System (INIS)

Reuter, W.G.; Server, W.L.

1982-01-01

Data from flat-plate specimens containing either triangular-, ellipsoidal- or rectangular-shaped surface flaws were evaluated by several potential analytical techniques. These techniques were modified as needed to predict conditions for initiation of subcritical crack growth, for the defect to penetrate the 6.4 mm (0.25 in.) wall thickness, and for instability (plastic or unstable). The modified analytical techniques developed from the plate specimens were then used to make predictions which are compared with test results obtained from pipe specimens containing triangular-shaped surface flaws

Probabilistic Estimation of Critical Flaw Sizes in the Primary Structure Welds of the Ares I-X Launch Vehicle

Science.gov (United States)

Pai, Shantaram S.; Hoge, Peter A.; Patel, B. M.; Nagpal, Vinod K.

2009-01-01

The primary structure of the Ares I-X Upper Stage Simulator (USS) launch vehicle is constructed of welded mild steel plates. There is some concern over the possibility of structural failure due to welding flaws. It was considered critical to quantify the impact of uncertainties in residual stress, material porosity, applied loads, and material and crack growth properties on the reliability of the welds during its pre-flight and flight. A criterion--an existing maximum size crack at the weld toe must be smaller than the maximum allowable flaw size--was established to estimate the reliability of the welds. A spectrum of maximum allowable flaw sizes was developed for different possible combinations of all of the above listed variables by performing probabilistic crack growth analyses using the ANSYS finite element analysis code in conjunction with the NASGRO crack growth code. Two alternative methods were used to account for residual stresses: (1) The mean residual stress was assumed to be 41 ksi and a limit was set on the net section flow stress during crack propagation. The critical flaw size was determined by parametrically increasing the initial flaw size and detecting if this limit was exceeded during four complete flight cycles, and (2) The mean residual stress was assumed to be 49.6 ksi (the parent material s yield strength) and the net section flow stress limit was ignored. The critical flaw size was determined by parametrically increasing the initial flaw size and detecting if catastrophic crack growth occurred during four complete flight cycles. Both surface-crack models and through-crack models were utilized to characterize cracks in the weld toe.

Development of flaw evaluation and acceptance procedures for flaw indications in the cooling water system at the Savannah River site K reactor

International Nuclear Information System (INIS)

Tandon, S.; Bamford, W.H.; Cowfer, C.D.; Ostrowski, R.

1993-01-01

This paper describes the methodology used in determining the criteria for acceptance of inspection indications in the K-Reactor Cooling Water System at the Savannah River Plant. These criteria have been developed in a manner consistent with the development of similar criteria in the ASME Code Section XI for commercial light water reactors, but with a realistic treatment of the operating conditions in the cooling water system. The technical basis for the development of these criteria called ''Acceptance Standards'' is contained in this paper. A second portion of this paper contains the methodology used in the construction of flaw evaluation charts which have been developed for each specific line size in the cooling water system. The charts provide the results of detailed fracture mechanics calculations which have been completed to determine the largest flaw which can be accepted in the cooling water system without repair. These charts are designed for use in conjunction with in-service inspections of the cooling water system, and only require inspection results to determine acceptability

Effect of combined loading due to bending and internal pressure on pipe flaw evaluation criteria

International Nuclear Information System (INIS)

Miura, Naoki; Sakai, Shinsuke

2008-01-01

Considering a rule for the rationalization of maintenance of Light Water Reactor piping, reliable flaw evaluation criteria are essential for determining how a detected flaw will be detrimental to continuous plant operation. Ductile fracture is one of the dominant failure modes that must be considered for carbon steel piping and can be analyzed by elastic-plastic fracture mechanics. Some analytical efforts have provided various flaw evaluation criteria using load correction factors, such as the Z-factors in the JSME codes on fitness-for-service for nuclear power plants and the section XI of the ASME boiler and pressure vessel code. The present Z-factors were conventionally determined, taking conservativity and simplicity into account; however, the effect of internal pressure, which is an important factor under actual plant conditions, was not adequately considered. Recently, a J-estimation scheme, LBB.ENGC for the ductile fracture analysis of circumferentially through-wall-cracked pipes subjected to combined loading was developed for more accurate prediction under more realistic conditions. This method explicitly incorporates the contributions of both bending and tension due to internal pressure by means of a scheme that is compatible with an arbitrary combined-loading history. In this study, the effect of internal pressure on the flaw evaluation criteria was investigated using the new J-estimation scheme. The Z-factor obtained in this study was compared with the presently used Z-factors, and the predictability of the current flaw evaluation criteria was quantitatively evaluated in consideration of the internal pressure. (author)

Stepped frequency imaging for flaw monitoring: Final report

International Nuclear Information System (INIS)

Hildebrand, B.P.

1988-09-01

This report summarizes the results of research into the usefulness of stepped frequency imaging (SFI) to nuclear power plant inspection. SFI is a method for producing ultrasonic holographic images without the need to sweep a two-dimensional aperture with the transducer. Instead, the transducer may be translated along a line. At each position of the transducer the frequency is stepped over a finite preselected bandwidth. The frequency stepped data is then processed to synthesize the second dimension. In this way it is possible to generate images in regions that are relatively inaccessible to two-dimensional scanners. This report reviews the theory and experimental work verifying the technique, and then explores its possible applications in the nuclear power industry. It also outlines how this new capability can be incorporated into the SDL-1000 Imaging System previously developed for EPRI. The report concludes with five suggestions for uses for the SFI method. These are: monitoring suspect or repaired regions of feedwater nozzles; monitoring pipe cracks repaired by weld overlay; monitoring crack depth during test block production; imaging flaws where access is difficult; and imaging flaws through cladding without distortion

Detection and characterization of flaws in segments of light water reactor pressure vessels

International Nuclear Information System (INIS)

Cook, K.V.; Cunningham, R.A. Jr.; McClung, R.W.

1988-01-01

Studies have been conducted to determine flaw density in segments cut from light water reactor )LWR) pressure vessels as part of the Oak Ridge National Laboratory's Heavy-Section Steel Technology (H SST) Program. Segments from the Hope Creek Unit 2 vessel and the Pilgrim Unit 2 Vessel were purchased from salvage dealers. Hope Creek was a boiling water reactor (BWR) design and Pilgrim was a pressurized water reactor (PWR) design. Neither were ever placed in service. Objectives were to evaluate these LWR segments for flaws with ultrasonic and liquid penetrant techniques. Both objectives were successfully completed. One significant indication was detected in a Hope Creek seam weld by ultrasonic techniques and characterized by further analyses terminating with destructive correlation. This indication [with a through-wall dimension of ∼6 mm (∼0.24 in.)] was detected in only 3 m (10 ft) of weldment and offers extremely limited data when compared to the extent of welding even in a single pressure vessel. However, the detection and confirmation of the flaw in the arbitrarily selected sections implies the Marshall report estimates (and others) are nonconservative for such small flaws. No significant indications were detected in the Pilgrim material by ultrasonic techniques. Unfortunately, the Pilgrim segments contained relatively little weldment; thus, we limited our ultrasonic examinations to the cladding and subcladding regions. Fluorescent liquid penetrant inspection of the cladding surfaces for both LWR segments detected no significant indications [i.e., for a total of approximately 6.8 m 2 (72 ft 2 ) of cladding surface]. (author)

Mode Selection for Axial Flaw Detection in Steam Generator Tube Using Ultrasonic Guided Wave

International Nuclear Information System (INIS)

Yoon, Byung Sik; Yang, Seung Han; Guon, Ki Il; Kim, Yong Sik

2009-01-01

The eddy current testing method is mainly used to inspect steam generator tube during in-service inspection period. But the general problem of assessing the structural integrity of the steam generator tube using eddy current inspection is rather complex due to the presence of noise and interference signal under various conditions. However, ultrasonic testing as a nondestructive testing tool has become quite popular and effective for the flaw detection and material characterization. Currently, ultrasonic guided wave is emerging technique in power industry because of its various merits. But most of previous studies are focused on detection of circumferential oriented flaws. In this study, the steam generator tube of nuclear power plant was selected to detect axially oriented flaws and investigate guided wave mode identification. The longitudinal wave mode is generated using piezoelectric transducer frequency from 0.5 MHz, 1.0 MHz, 2.25MHz and 5MHz. Dispersion based STFT algorithm is used as mode identification tool

Evaluation of constraint methodologies applied to a shallow-flaw cruciform bend specimen tested under biaxial loading conditions

International Nuclear Information System (INIS)

Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

1998-01-01

A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a prototypic, far-field. out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for RPV materials. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies. namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness, the conventional maximum principal stress criterion indicated no effect

According to Jim: The Flawed Normal Curve of Intelligence

Science.gov (United States)

Gallagher, James J.

2008-01-01

In this article, the author talks about the normal curve of intelligence which he thinks is flawed and contends that wrong conclusions have been drawn based on this spurious normal curve. An example is that of racial and ethnic differences wherein some authors maintain that some ethnic and racial groups are clearly superior to others based on…

Evaluation of Manual Ultrasonic Examinations Applied to Detect Flaws in Primary System Dissimilar Metal Welds at North Anna Power Station

International Nuclear Information System (INIS)

Anderson, Michael T.; Diaz, Aaron A.; Doctor, Steven R.

2012-01-01

During a recent inservice inspection (ISI) of a dissimilar metal weld (DMW) in an inlet (hot leg) steam generator nozzle at North Anna Power Station Unit 1, several axially oriented flaws went undetected by the licensee's manual ultrasonic testing (UT) technique. The flaws were subsequently detected as a result of outside diameter (OD) surface machining in preparation for a full structural weld overlay. The machining operation uncovered the existence of two through-wall flaws, based on the observance of primary water leaking from the DMW. Further ultrasonic tests were then performed, and a total of five axially oriented flaws, classified as primary water stress corrosion cracking (PWSCC), were detected in varied locations around the weld circumference.

An engineering approach for examining crack growth and stability in flawed structures

International Nuclear Information System (INIS)

Shih, C.F.; German, M.D.; Kumar, V.

1981-01-01

Progress made in two research programmes, sponsored by the Electric Power Research Institute (EPRI), to identify viable parameters for characterising crack initiation and continued extension are summarised. An engineering/design methodology, based on these parameters, for the assessment of crack growth and instability in engineering structures which are stressed beyond the regime of applicability of linear elastic fracture mechanics is developed. The ultimate goal in the development of such a methodology is to establish an improved basis for analysing the effect of flaws (postulated or detected) on the safety margins of pressure boundary components of light water-cooled type nuclear steam supply systems. The methodology can also be employed for structural integrity analyses of other engineering components. Extensive experimental and analytical investigations undertaken to evaluate potential criteria for crack initiation and growth and the selection of the final criteria for analysing crack growth and stability in flawed structures are summarised. The experimental and analytical results obtained to date suggest that parameters based on the J-integral and the crack tip opening displacement, delta, are the most promising. This is not surprising since, from a theoretical basis, the two approaches are similar if certain conditions are met. An engineering/design approach for the assessment of crack growth and instability in flawed structures is outlined. (author)

Development of flaw assesment methodology for elevated temperature components of FBR plants

International Nuclear Information System (INIS)

Shimakawa, Takashi; Takahashi, Yukio; Miura, Naoki; Nakayama, Yasunari; Sawai, Tatsuaki; Tooya, Yuuji

1999-01-01

Fracture mechanics is applicable for the safety assessment of FBR component if a crack is assumed to exist. Inelastic response should be taken into account due to high temperature operation of FBR components. However, methodology for the application of inelastic fracture mechanics has not been established sufficiently. CRIEPI has been conducted research projects to develop a flaw assessment guideline for FBR components. This guideline consists of evaluation methods for creep-fatigue crack propagation, ductile fracture and sodium leak rate. The summary of evaluation methods on creep-fatigue crack and ductile fracture is presented in this paper. (author)

Fracture assessment of HSST Plate 14 shallow-flaw cruciform bend specimens tested under biaxial loading conditions

Energy Technology Data Exchange (ETDEWEB)

Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

1998-06-01

A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow, surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a far-field, out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for an RPV material. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies, namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness; the conventional maximum principal stress criterion indicated no effect. A three-parameter Weibull model based on the hydrostatic stress criterion is shown to correlate the experimentally observed biaxial effect on cleavage fracture toughness by providing a scaling mechanism between uniaxial and biaxial loading states.

Residual stress improvement for pipe weld by means of induction heating pre-flawed pipe

International Nuclear Information System (INIS)

Umemoto, T.; Yoshida, K.; Okamoto, A.

1980-01-01

The intergranular stress corrosion cracking (IGSCC) has been found in type 304 stainless steel piping of several BWR plants. It is already well known that IGSCC is most likely to occur when three essential factors, material sensitization, high tensile stress and corrosive environment, are present. If the welding residual stress is sufficiently high (200 to approximately 400 MPa) in the inside piping surface near the welded joint, then it may be one of the biggest contributors to IGSCC. If the residual stress is reduced or reversed by some way, the IGSCC will be effectively mitigated. In this paper a method to improve the residual stress named IHSI (Induction Heating Stress Improvement) is explained. IHSI aims to improve the condition of residual stress in the inside pipe surface using the thermal stress induced by the temperature difference in pipe wall, that is produced when the pipe is heated from the outside surface by an induction heating coil and cooled on the inside surface by water simultaneously. This method becomes more attractive when it can be successfully applied to in-service piping which might have some pre-flaw. In order to verify the validity of IHSI for such piping, some experiments and calculations using finite element method were conducted. These results are mainly discussed in this paper from the view-points of residual stress, flaw behaviour during IHSI and material deterioration. (author)

A general approach to flaw simulation in castings by superimposing projections of 3D models onto real X-ray images

International Nuclear Information System (INIS)

Hahn, D.; Mery, D.

2003-01-01

In order to evaluate the sensitivity of defect inspection systems, it is convenient to examine simulated data. This gives the possibility to tune the parameters of the inspection method and to test the performance of the system in critical cases. In this paper, a practical method for the simulation of defects in radioscopic images of aluminium castings is presented. The approach simulates only the flaws and not the whole radioscopic image of the object under test. A 3D mesh is used to model a flaw with complex geometry, which is projected and superimposed onto real radioscopic images of a homogeneous object according to the exponential attenuation law for X- rays. The new grey value of a pixel, where the 3D flaw is projected, depends only on four parameters: (a) the grey value of the original X-ray image without flaw; (b) the linear absorption coefficient of the examined material; (c) the maximal thickness observable in the radioscopic image; and (d) the length of the intersection of the 3D flaw with the modelled X-ray beam, that is projected into the pixel. A simulation of a complex flaw modelled as a 3D mesh can be performed in any position of the castings by using the algorithm described in this paper. This allows the evaluation of the performance of defect inspection systems in cases where the detection is known to be difficult. In this paper, we show experimental results on real X-ray images of aluminium wheels, in which 3D flaws like blowholes, cracks and inclusions are simulated

Preclinical animal anxiety research - flaws and prejudices.

Science.gov (United States)

Ennaceur, Abdelkader; Chazot, Paul L

2016-04-01

The current tests of anxiety in mice and rats used in preclinical research include the elevated plus-maze (EPM) or zero-maze (EZM), the light/dark box (LDB), and the open-field (OF). They are currently very popular, and despite their poor achievements, they continue to exert considerable constraints on the development of novel approaches. Hence, a novel anxiety test needs to be compared with these traditional tests, and assessed against various factors that were identified as a source of their inconsistent and contradictory results. These constraints are very costly, and they are in most cases useless as they originate from flawed methodologies. In the present report, we argue that the EPM or EZM, LDB, and OF do not provide unequivocal measures of anxiety; that there is no evidence of motivation conflict involved in these tests. They can be considered at best, tests of natural preference for unlit and/or enclosed spaces. We also argued that pharmacological validation of a behavioral test is an inappropriate approach; it stems from the confusion of animal models of human behavior with animal models of pathophysiology. A behavioral test is developed to detect not to produce symptoms, and a drug is used to validate an identified physiological target. In order to overcome the major methodological flaws in animal anxiety studies, we proposed an open space anxiety test, a 3D maze, which is described here with highlights of its various advantages over to the traditional tests.

An algorithm for analytical solution of basic problems featuring elastostatic bodies with cavities and surface flaws

Science.gov (United States)

Penkov, V. B.; Levina, L. V.; Novikova, O. S.; Shulmin, A. S.

2018-03-01

Herein we propose a methodology for structuring a full parametric analytical solution to problems featuring elastostatic media based on state-of-the-art computing facilities that support computerized algebra. The methodology includes: direct and reverse application of P-Theorem; methods of accounting for physical properties of media; accounting for variable geometrical parameters of bodies, parameters of boundary states, independent parameters of volume forces, and remote stress factors. An efficient tool to address the task is the sustainable method of boundary states originally designed for the purposes of computerized algebra and based on the isomorphism of Hilbertian spaces of internal states and boundary states of bodies. We performed full parametric solutions of basic problems featuring a ball with a nonconcentric spherical cavity, a ball with a near-surface flaw, and an unlimited medium with two spherical cavities.

Twenty years of fracture mechanics and flaw evaluation applications in the ASME Nuclear Code

International Nuclear Information System (INIS)

Riccardella, P.C.

1991-01-01

The paper presents a retrospective on the development and applications of fracture mechanics-based toughness requirements and flaw evaluation methodology in Sections III and XI of the ASME Code. Section III developments range from the rules and requirements for thick section Class 1 pressure vessels to thinner section components in other Classes. Section XI applications include flaw acceptance standards and evaluation methodology for various components ranging from pressure vessels to thins section piping of carbon and austenitic steels. The experience gained in operating plant applications of these rules and procedures are also discussed

Statistical flaws in design and analysis of fertility treatment studies on cryopreservation raise doubts on the conclusions

Science.gov (United States)

van Gelder, P.H.A.J.M.; Nijs, M.

2011-01-01

Decisions about pharmacotherapy are being taken by medical doctors and authorities based on comparative studies on the use of medications. In studies on fertility treatments in particular, the methodological quality is of utmost importance in the application of evidence-based medicine and systematic reviews. Nevertheless, flaws and omissions appear quite regularly in these types of studies. Current study aims to present an overview of some of the typical statistical flaws, illustrated by a number of example studies which have been published in peer reviewed journals. Based on an investigation of eleven studies at random selected on fertility treatments with cryopreservation, it appeared that the methodological quality of these studies often did not fulfil the required statistical criteria. The following statistical flaws were identified: flaws in study design, patient selection, and units of analysis or in the definition of the primary endpoints. Other errors could be found in p-value and power calculations or in critical p-value definitions. Proper interpretation of the results and/or use of these study results in a meta analysis should therefore be conducted with care. PMID:24753877

Statistical flaws in design and analysis of fertility treatment -studies on cryopreservation raise doubts on the conclusions.

Science.gov (United States)

van Gelder, P H A J M; Nijs, M

2011-01-01

Decisions about pharmacotherapy are being taken by medical doctors and authorities based on comparative studies on the use of medications. In studies on fertility treatments in particular, the methodological quality is of utmost -importance in the application of evidence-based medicine and systematic reviews. Nevertheless, flaws and omissions appear quite regularly in these types of studies. Current study aims to present an overview of some of the typical statistical flaws, illustrated by a number of example studies which have been published in peer reviewed journals. Based on an investigation of eleven studies at random selected on fertility treatments with cryopreservation, it appeared that the methodological quality of these studies often did not fulfil the -required statistical criteria. The following statistical flaws were identified: flaws in study design, patient selection, and units of analysis or in the definition of the primary endpoints. Other errors could be found in p-value and power calculations or in critical p-value definitions. Proper -interpretation of the results and/or use of these study results in a meta analysis should therefore be conducted with care.

Formation and ridging of flaw leads in the eastern Canadian Beaufort Sea. Special Session C06 on: “Physical, biological and biogeochemical processes associated with young thin ice types”

Science.gov (United States)

Prinsenberg, S. J.

2009-12-01

Formation and ridging of flaw leads in the eastern Canadian Beaufort Sea. Simon Prinsenberg1 and Yves Graton2 1Bedford Inst. of Oceanography, Fisheries and Oceans Canada P.O. Box1006, Dartmouth, Nova Scotia, B2Y 4A2, Canada prinsenbergs@mar.dfo-mpo.gc.ca 2Inst. National de la Recherche Scientifique-Eau, INRS-ETE University of Quebec at Quebec City, Quebec yvesgratton@eteinrs.ca During the winter of 2008, the flaw lead south of Banks Island repeatedly opened and closed representing an elongated region where periodically the large ice growth stimulates the densification of the surface layer due to salt rejection and instigates a local circulation pattern that will affect the biological processes of the region. Helicopter-borne sensors were available to monitor the aftermath of one of the rapid closing of the flaw lead into extensive elongated rubble field using a Canadian Ice breaker, CCGS Amundsen, as a logistic base. After the wind reversed a new open flaw lead 20km wide restarting a new flaw lead formation cycle. Ice thickness and surface roughness data were collected from the rubble field and adjacent open flaw lead with an Electromagnetic-Laser system. The strong wind event of April 4-5 2009 generated a large linear 1.5km wide ice rubble field up to 8-10m thick when the 60cm thick, 18km wide flaw lead was crunched into land-fast by the 1.5m thick offshore pack ice. It is expected that during rapid ice growth in a flaw lead, salt rejection increase the density of the surface water layer producing a surface depression (Low) and cyclonic circulation. In contrast at depth, the extra surface dense water produces a high in the horizontal pressure field and anti-cyclonic circulation which remains after the rapid ice growth within the flaw lead stops. One of such remnants may have been observed during the CFL-IPY winter survey.

Application of Fourier elastodynamics to direct and inverse problems for the scattering of elastic waves from flaws near surfaces

International Nuclear Information System (INIS)

Richardson, J.M.; Fertig, K.W. Jr.

1983-01-01

In order to inspect flaws which lie too close to the surface a Fourier elastodynamic formalism is proposed which enables one to decompose the elastodynamic system into separately charterizable parts by means of planes perpendicular to the z-axis. The process can be represented by a generalized transfer function relating the near-field scattered waves to the waves incident on a slab of material containing the flaw. The Fourier elastodynamics are applied to the characterization of the total scattering process involving a flaw at various distances from a plastic-water interface. An abbreviated discussion of Fourier elastodynamics is presented, and the results specialized to the case of spherical voids and inclusions bear an interface. Finally, the computational results for several ranges of temporal frequency and for a sequence of values of the distance from the flaw center to the interface are discussed

Research on Automatic Positioning System of Ultrasonic Testing of Wind Turbine Blade Flaws

Science.gov (United States)

Liu, Q. X.; Wang, Z. H.; Long, S. G.; Cai, M.; Cai, M.; Wang, X.; Chen, X. Y.; Bu, J. L.

2017-11-01

Ultrasonic testing technology has been used essentially in non-destructive testing of wind turbine blades. However, it is fact that the ultrasonic flaw detection method has inefficiently employed in recent years. This is because the testing result will illustrate a small deviation due to the artificial, environmental and technical factors. Therefore, it is an urgent technical demand for engineers to test the various flaws efficiently and quickly. An automatic positioning system has been designed in this paper to record the moving coordinates and the target distance in real time. Simultaneously, it could launch and acquire the sonic wave automatically. The ADNS-3080 optoelectronic chip is manufactured by Agilent Technologies Inc, which is also utilized in the system. With the combination of the chip, the power conversion module and the USB transmission module, the collected data can be transmitted from the upper monitor to the hardware that could process and control the data through software programming. An experiment has been designed to prove the reliability of automotive positioning system. The result has been validated by comparing the result collected form LABVIEW and actual plots on Perspex plane, it concludes that the system possesses high accuracy and magnificent meanings in practical engineering.

The Self-Concept. Volume 1, A Review of Methodological Considerations and Measuring Instruments. Revised Edition.

Science.gov (United States)

Wylie, Ruth C.

This volume of the revised edition describes and evaluates measurement methods, research designs, and procedures which have been or might appropriately be used in self-concept research. Working from the perspective that self-concept or phenomenal personality theories can be scientifically investigated, methodological flaws and questionable…

Examination of parameters affecting overload fracture behavior of flaw-tip hydrides in Zr-2.5Nb pressure tubes in Candu reactors

International Nuclear Information System (INIS)

Cui, J.; Shek, G.K.; Wang, Z.R.

2007-01-01

Service-induced flaws in Zr-2.5Nb alloy pressure tubes in Candu (Canada Deuterium Uranium Reactors) nuclear reactors are susceptible to a crack initiation and growth mechanism known as Delayed Hydride Cracking (DHC), which is a repetitive process that involves hydrogen diffusion, hydride precipitation, growth and fracture of a hydride region at the flaw-tip under a constant load. Crack initiation may also occur under another loading condition when the hydride region is subjected to an overload. An overload occurs when the hydride region at the flaw tip is loaded to a stress higher than that at which this region is formed such as when the reactor experiences a transient pressure higher than the normal operating pressure where the hydride region is formed. Flaw disposition requires justification that the hydride region overload will not fracture the hydride region, and initiate DHC. In this work, monotonically increasing load experiments were performed on unirradiated Zr-2.5Nb pressure tube specimens containing simulated debris frets (V-notch) and bearing pad frets (BPF, U-shape notch) to examine overload fracture behavior of flaw-tip hydrides formed under hydride ratcheting conditions. Hydride cracking in the overload tests was detected by the acoustic emission technique and confirmed by post-test metallurgical examination. Test results indicate that the resistance to overload fracture is affected by a number of parameters including hydride formation stress, flaw shape (V-notch vs. BPF) and flaw radius (0.015 mm vs. 0.1 mm). The notch-tip hydride morphologies were examined by optical microscopy and scanning electron microscopy (SEM) which show that they are affected by the hydride formation conditions, resulting in different overload fracture resistance. Finite element stress analyses were also performed to obtain flaw-tip stress distributions for interpretation of the test results. (authors)

Amplitude-independent flaw length determination using differential eddy current

Science.gov (United States)

Shell, E.

2013-01-01

Military engine component manufacturers typically specify the eddy current (EC) inspection requirements as a crack length or depth with the assumption that the cracks in both the test specimens and inspected component are of a similar fixed aspect ratio. However, differential EC response amplitude is dependent on the area of the crack face, not the length or depth. Additionally, due to complex stresses, in-service cracks do not always grow in the assumed manner. It would be advantageous to use more of the information contained in the EC data to better determine the full profile of cracks independent of the fixed aspect ratio amplitude response curve. A specimen with narrow width notches is used to mimic cracks of varying aspect ratios in a controllable manner. The specimen notches have aspect ratios that vary from 1:1 to 10:1. Analysis routines have been developed using the shape of the EC response signals that can determine the length of a surface flaw of common orientations without use of the amplitude of the signal or any supporting traditional probability of detection basis. Combined with the relationship between signal amplitude and area, the depth of the flaw can also be calculated.

Investigation of the radiation leakage from X ray flaw detectors and the improvement measures for the unqualified products

International Nuclear Information System (INIS)

Li Yiachun; Wu Yi; Pang Hu; Bai Bin

1997-01-01

The authors introduce investigation methods and results for radiation leakage from X ray flaw detectors, which are used in Beijing area. Total 21 sets of flaw detectors made in 8 factories in Beijing, Shanghai etc. have been tested, of which 16 sets made in Beijing, Dandong and Japan are gas cooling flaw detectors, and rest 5 sets made in Shanghai and Germany are water or oil cooling detectors. The air Kerma rate of leakage radiation at 1 m from the X ray tube target were measured by Type FJ-347A X, γ dosimeter. It can be seen from the results that, compared with the trade standard ZBY315-83, 5 sets of water or oil cooling flaw detectors are all qualified. However, only two sets of gas cooling detectors are qualified, and the radiation leakage of another 14 sets are over the values specified in the standard. The reason is analyzed, and some advices about the measures of improving radiation protection structure design and production technology for the unqualified products have been proposed

Gun bore flaw image matching based on improved SIFT descriptor

Science.gov (United States)

Zeng, Luan; Xiong, Wei; Zhai, You

2013-01-01

In order to increase the operation speed and matching ability of SIFT algorithm, the SIFT descriptor and matching strategy are improved. First, a method of constructing feature descriptor based on sector area is proposed. By computing the gradients histogram of location bins which are parted into 6 sector areas, a descriptor with 48 dimensions is constituted. It can reduce the dimension of feature vector and decrease the complexity of structuring descriptor. Second, it introduce a strategy that partitions the circular region into 6 identical sector areas starting from the dominate orientation. Consequently, the computational complexity is reduced due to cancellation of rotation operation for the area. The experimental results indicate that comparing with the OpenCV SIFT arithmetic, the average matching speed of the new method increase by about 55.86%. The matching veracity can be increased even under some variation of view point, illumination, rotation, scale and out of focus. The new method got satisfied results in gun bore flaw image matching. Keywords: Metrology, Flaw image matching, Gun bore, Feature descriptor

Development of a Weibull model of cleavage fracture toughness for shallow flaws in reactor pressure vessel material

Energy Technology Data Exchange (ETDEWEB)

Bass, B.R.; Williams, P.T.; McAfee, W.J.; Pugh, C.E. [Oak Ridge National Lab., Heavy-Section Steel Technology Program, Oak Ridge, TN (United States)

2001-07-01

A primary objective of the United States Nuclear Regulatory Commission (USNRC) -sponsored Heavy-Section Steel Technology (HSST) Program is to develop and validate technology applicable to quantitative assessments of fracture prevention margins in nuclear reactor pressure vessels (RPVs) containing flaws and subjected to service-induced material toughness degradation. This paper describes an experimental/analytical program for the development of a Weibull statistical model of cleavage fracture toughness for applications to shallow surface-breaking and embedded flaws in RPV materials subjected to multi-axial loading conditions. The experimental part includes both material characterization testing and larger fracture toughness experiments conducted using a special-purpose cruciform beam specimen developed by Oak Ridge National Laboratory for applying biaxial loads to shallow cracks. Test materials (pressure vessel steels) included plate product forms (conforming to ASTM A533 Grade B Class 1 specifications) and shell segments procured from a pressurized-water reactor vessel intended for a nuclear power plant. Results from tests performed on cruciform specimens demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower-transition temperature region. A local approach methodology based on a three-parameter Weibull model was developed to correlate these experimentally-observed biaxial effects on fracture toughness. The Weibull model, combined with a new hydrostatic stress criterion in place of the more commonly used maximum principal stress in the kernel of the Weibull stress integral definition, is shown to provide a scaling mechanism between uniaxial and biaxial loading states for 2-dimensional flaws located in the A533-B plate material. The Weibull stress density was introduced as a matrice for identifying regions along a semi-elliptical flaw front that have a higher probability of cleavage initiation. Cumulative

Development of a Weibull model of cleavage fracture toughness for shallow flaws in reactor pressure vessel material

International Nuclear Information System (INIS)

Bass, B.R.; Williams, P.T.; McAfee, W.J.; Pugh, C.E.

2001-01-01

A primary objective of the United States Nuclear Regulatory Commission (USNRC) -sponsored Heavy-Section Steel Technology (HSST) Program is to develop and validate technology applicable to quantitative assessments of fracture prevention margins in nuclear reactor pressure vessels (RPVs) containing flaws and subjected to service-induced material toughness degradation. This paper describes an experimental/analytical program for the development of a Weibull statistical model of cleavage fracture toughness for applications to shallow surface-breaking and embedded flaws in RPV materials subjected to multi-axial loading conditions. The experimental part includes both material characterization testing and larger fracture toughness experiments conducted using a special-purpose cruciform beam specimen developed by Oak Ridge National Laboratory for applying biaxial loads to shallow cracks. Test materials (pressure vessel steels) included plate product forms (conforming to ASTM A533 Grade B Class 1 specifications) and shell segments procured from a pressurized-water reactor vessel intended for a nuclear power plant. Results from tests performed on cruciform specimens demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower-transition temperature region. A local approach methodology based on a three-parameter Weibull model was developed to correlate these experimentally-observed biaxial effects on fracture toughness. The Weibull model, combined with a new hydrostatic stress criterion in place of the more commonly used maximum principal stress in the kernel of the Weibull stress integral definition, is shown to provide a scaling mechanism between uniaxial and biaxial loading states for 2-dimensional flaws located in the A533-B plate material. The Weibull stress density was introduced as a matrice for identifying regions along a semi-elliptical flaw front that have a higher probability of cleavage initiation. Cumulative

Vitamin D and Depression: A Systematic Review and Meta-Analysis Comparing Studies with and without Biological Flaws

OpenAIRE

Simon Spedding

2014-01-01

Efficacy of Vitamin D supplements in depression is controversial, awaiting further literature analysis. Biological flaws in primary studies is a possible reason meta-analyses of Vitamin D have failed to demonstrate efficacy. This systematic review and meta-analysis of Vitamin D and depression compared studies with and without biological flaws. The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The literature search was un...

Spallation model for the high strain rates range

Science.gov (United States)

Dekel, E.; Eliezer, S.; Henis, Z.; Moshe, E.; Ludmirsky, A.; Goldberg, I. B.

1998-11-01

Measurements of the dynamic spall strength in aluminum and copper shocked by a high power laser to pressures of hundreds of kbars show a rapid increase in the spall strength with the strain rate at values of about 107 s-1. We suggest that this behavior is a result of a change in the spall mechanism. At low strain rates the spall is caused by the motion and coalescence of material's initial flaws. At high strain rates there is not enough time for the flaws to move and the spall is produced by the formation and coalescence of additional cavities where the interatomic forces become dominant. Material under tensile stress is in a metastable condition and cavities of a critical radius are formed in it due to thermal fluctuations. These cavities grow due to the tension. The total volume of the voids grow until the material disintegrates at the spall plane. Simplified calculations based on this model, describing the metal as a viscous liquid, give results in fairly good agreement with the experimental data and predict the increase in spall strength at high strain rates.

The Secret of Future Defeat: The Evolution of US Joint and Army Doctrine 1993-2006 and the Flawed Conception of Stability Operations

Science.gov (United States)

2007-05-24

The Secret of Future Defeat: the Evolution of US Joint and Army Doctrine 1993-2006 and the Flawed Conception of Stability Operations A...4. TITLE AND SUBTITLE The Secret of Future Defeat: the Evolution of US Joint and 5a. CONTRACT NUMBER Army Doctrine 1993-2006 and the Flawed... The Secret of Future Defeat: the Evolution of US Joint and Army Doctrine 1993-2006 and the Flawed Conception of Stability Operations Approved by

Fracture behaviour assessment of a flawed pressure vessel in the hydro-test

Energy Technology Data Exchange (ETDEWEB)

Sarkimo, M; Rintamac, R

1988-12-31

This document deals with the fracture properties of a flawed pressure vessel. The experiment was carried out within the Nordic Countries on a vessel in a Finnish refinery. The instrumentation used included acoustic emission. Some results are provided. (TEC).

Recent changes in French flaw evaluation procedures: RSE-M

International Nuclear Information System (INIS)

Faidy, C.

2001-01-01

After a general presentation of the RSE-M, the French Code which describes the rules for in-service inspection of nuclear power plant components, this paper will be focused on the major new developments of the flaw evaluation procedure: critical crack size evaluation, material properties, safety factors and the major validation tasks done to support the RSE-M, edition 2000. The paper will conclude on on-going development in this area. (author)

Recent changes in French flaw evaluation procedures: RSE-M

Energy Technology Data Exchange (ETDEWEB)

Faidy, C. [Electricite de France (EDF-SEPTEN), 69 - Villeurbanne (France)

2001-07-01

After a general presentation of the RSE-M, the French Code which describes the rules for in-service inspection of nuclear power plant components, this paper will be focused on the major new developments of the flaw evaluation procedure: critical crack size evaluation, material properties, safety factors and the major validation tasks done to support the RSE-M, edition 2000. The paper will conclude on on-going development in this area. (author)

Stabilized transistor transformer for self-moving Sirena-1 X-ray flaw detector

International Nuclear Information System (INIS)

Krasil'nikov, S.B.; Kristalinskij, A.L.; Lozovoj, L.N.; Markov, S.N.; Sindalovskij, E.I.

1986-01-01

Electric circuit of stabilized transistor transformer for self-moving ''Sirena'' type X-ray flaw detector is described. Specifications of the transformer and results of the experimental studies, which can be used when tuning and adjusting the transformer under industrial conditions

On self-propagating methodological flaws in performance normalization for strength and power sports.

Science.gov (United States)

Arandjelović, Ognjen

2013-06-01

Performance in strength and power sports is greatly affected by a variety of anthropometric factors. The goal of performance normalization is to factor out the effects of confounding factors and compute a canonical (normalized) performance measure from the observed absolute performance. Performance normalization is applied in the ranking of elite athletes, as well as in the early stages of youth talent selection. Consequently, it is crucial that the process is principled and fair. The corpus of previous work on this topic, which is significant, is uniform in the methodology adopted. Performance normalization is universally reduced to a regression task: the collected performance data are used to fit a regression function that is then used to scale future performances. The present article demonstrates that this approach is fundamentally flawed. It inherently creates a bias that unfairly penalizes athletes with certain allometric characteristics, and, by virtue of its adoption in the ranking and selection of elite athletes, propagates and strengthens this bias over time. The main flaws are shown to originate in the criteria for selecting the data used for regression, as well as in the manner in which the regression model is applied in normalization. This analysis brings into light the aforesaid methodological flaws and motivates further work on the development of principled methods, the foundations of which are also laid out in this work.

Eddy current probe and method for flaw detection in metals

Science.gov (United States)

Watjen, John P.

1987-06-23

A flaw detecting system is shown which includes a probe having a pair of ferrite cores with in-line gaps in close proximity to each other. An insulating, non-magnetic, non-conducting holder fills the gaps and supports the ferrite cores in a manner such that the cores form a generally V-shape. Each core is provided with an excitation winding and a detection winding. The excitation windings are connected in series or parallel with an rf port for connection thereof to a radio frequency source. The detection windings, which are differentially wound, are connected in series circuit to a detector port for connection to a voltage measuring instrument. The ferrite cores at the in-line gaps directly engage the metal surface of a test piece, and the probe is scanned along the test piece. In the presence of a flaw in the metal surface the detection winding voltages are unbalanced, and the unbalance is detected by the voltage measuring instrument. The insulating holder is provided with a profile which conforms to that of a prominent feature of the test piece to facilitate movement of the probe along the feature, typically an edge or a corner.

Development of portable phased array UT system for real-time flaw imaging

International Nuclear Information System (INIS)

Goto, M.

1995-01-01

Many functions and features of phased array UT technology must be useful for NDE in the industrial field. Some phased array UT systems have been developed for the inspection of nuclear pressure vessel and turbine components. However, phased array UT is still a special NDE technique and it has not been used widely in the past. The reasons of that are system size, cost, operator performance, equipment design and others. TOSHIBA has newly developed PC controlled portable phased array system to solve those problems. The portable phased array UT system is very compact and light but it is able to drive up to 32-channel linear array probe, to display real-time linear/sector B-scan, to display accumulated B-scan with an encoder and to display profile overlaid B-scan. The first applications were turbine component inspections for precise flaw investigation and flaw image data recording

Fatigue crack initiation at complex flaws in hydrided Zr-2.5%Nb samples from CANDU pressure tubes

International Nuclear Information System (INIS)

Stoica, L.; Radu, V.

2016-01-01

The paper addresses the phenomena which occur at locations where the oxide layer of the inner surface of CANDU tube pressure is damaged by the contact with the fuel element or due to the action of hard particles at the interface between the tube pressure and bearing pad of fuel element. In such situations generate defects, which most often are defects known as ''bearing pad fretting flaws'' or ''debris fretting flaws''. In this paper the experiments are completed in a series of previous works on the mechanical fatigue phenomenon on samples prepared from the pressure tube Zr-2.5% Nb alloy. The phenomenon of variable mechanical stress (or fatigue) may lead to initiation of cracks at the tip of volumetric flaws, according to the accumulation of hydrides, which then fractures and can propagate through the tube wall pressure due to the mechanism of type DHC (Delayed Hydride Cracking). (authors)

The use of fracture mechanics for the evaluation of NDE flaw acceptance standards

Energy Technology Data Exchange (ETDEWEB)

Alicino, A; Capurro, E; Ansaldo, Sp; Corvi, A [Ansaldo SpA, Genoa (Italy)

1988-12-31

This document deals with the use of fracture mechanics criteria to evaluate the Non Destructive Examination (NDE) flaw acceptance standards. The communication discusses the general schemes and the guidelines of the activity carried out. (TEC).

Determination of Flaw Type and Location Using an Expert Module in Ultrasonic Nondestructive Testing for Weld Inspection

Science.gov (United States)

Shahriari, D.; Zolfaghari, A.; Masoumi, F.

2011-01-01

Nondestructive evaluation is explained as nondestructive testing, nondestructive inspection, and nondestructive examination. It is a desire to determine some characteristic of the object or to determine whether the object contains irregularities, discontinuities, or flaws. Ultrasound based inspection techniques are used extensively throughout industry for detection of flaws in engineering materials. The range and variety of imperfections encountered is large, and critical assessment of location, size, orientation and type is often difficult. In addition, increasing quality requirements of new standards and codes of practice relating to fitness for purpose are placing higher demands on operators. Applying of an expert knowledge-based analysis in ultrasonic examination is a powerful tool that can help assure safety, quality, and reliability; increase productivity; decrease liability; and save money. In this research, an expert module system is coupled with ultrasonic examination (A-Scan Procedure) to determine and evaluate type and location of flaws that embedded during welding parts. The processing module of this expert system is implemented based on EN standard to classify welding defects, acceptance condition and measuring of their location via echo static pattern and image processing. The designed module introduces new system that can automate evaluating of the results of A-scan method according to EN standard. It can simultaneously recognize the number and type of defects, and determine flaw position during each scan.

Modeling validation to structural flaws in the foundations of oil tanks

International Nuclear Information System (INIS)

Couto, Larissa Goncalves; Leite, Sandro Passos

2014-01-01

This paper presents the modeling of an experiment used to study the application of backscattered neutrons in the identification of structural flaws in the foundations of oil tanks. This modeling was a preliminary validation procedure of the method of calculation, performed with the radiation transport code MCNP, to study the application of backscattered neutrons as inspection tool. (author)

Acoustic emission and estimation of flaw significance in reactor pressure boundaries

International Nuclear Information System (INIS)

Hutton, P.H.; Kurtz, R.J.

1982-01-01

The work discussed is intended to establish the feasibility of using acoustic emission (AE) to detect and evaluate growing flaws in nuclear reactor pressure boundaries. Basic AE identification and interpretation methods have grown out of Phase 1. Phases 2 and 3 to test and demonstrate developed methodology on a vessel test and on a reactor are in progress

Windows Vista Kernel-Mode: Functions, Security Enhancements and Flaws

Directory of Open Access Journals (Sweden)

Mohammed D. ABDULMALIK

2008-06-01

Full Text Available Microsoft has made substantial enhancements to the kernel of the Microsoft Windows Vista operating system. Kernel improvements are significant because the kernel provides low-level operating system functions, including thread scheduling, interrupt and exception dispatching, multiprocessor synchronization, and a set of routines and basic objects.This paper describes some of the kernel security enhancements for 64-bit edition of Windows Vista. We also point out some weakness areas (flaws that can be attacked by malicious leading to compromising the kernel.

The detection of tightly closed flaws by nondestructive testing (NDT) methods. [fatigue crack formation in aluminum alloy test specimens

Science.gov (United States)

Rummel, W. D.; Rathke, R. A.; Todd, P. H., Jr.; Mullen, S. J.

1975-01-01

Liquid penetrant, ultrasonic, eddy current and X-radiographic techniques were optimized and applied to the evaluation of 2219-T87 aluminum alloy test specimens in integrally stiffened panel, and weld panel configurations. Fatigue cracks in integrally stiffened panels, lack-of-fusion in weld panels, and fatigue cracks in weld panels were the flaw types used for evaluation. A 2319 aluminum alloy weld filler rod was used for all welding to produce the test specimens. Forty seven integrally stiffened panels containing a total of 146 fatigue cracks, ninety three lack-of-penetration (LOP) specimens containing a total of 239 LOP flaws, and one-hundred seventeen welded specimens containing a total of 293 fatigue cracks were evaluated. Nondestructive test detection reliability enhancement was evaluated during separate inspection sequences in the specimens in the 'as-machined or as-welded', post etched and post proof loaded conditions. Results of the nondestructive test evaluations were compared to the actual flaw size obtained by measurement of the fracture specimens after completing all inspection sequences. Inspection data were then analyzed to provide a statistical basis for determining the flaw detection reliability.

High call volume at poison control centers: identification and implications for communication.

Science.gov (United States)

Caravati, E M; Latimer, S; Reblin, M; Bennett, H K W; Cummins, M R; Crouch, B I; Ellington, L

2012-09-01

High volume surges in health care are uncommon and unpredictable events. Their impact on health system performance and capacity is difficult to study. To identify time periods that exhibited very busy conditions at a poison control center and to determine whether cases and communication during high volume call periods are different from cases during low volume periods. Call data from a US poison control center over twelve consecutive months was collected via a call logger and an electronic case database (Toxicall®).Variables evaluated for high call volume conditions were: (1) call duration; (2) number of cases; and (3) number of calls per staff member per 30 minute period. Statistical analyses identified peak periods as busier than 99% of all other 30 minute time periods and low volume periods as slower than 70% of all other 30 minute periods. Case and communication characteristics of high volume and low volume calls were compared using logistic regression. A total of 65,364 incoming calls occurred over 12 months. One hundred high call volume and 4885 low call volume 30 minute periods were identified. High volume periods were more common between 1500 and 2300 hours and during the winter months. Coded verbal communication data were evaluated for 42 high volume and 296 low volume calls. The mean (standard deviation) call length of these calls during high volume and low volume periods was 3 minutes 27 seconds (1 minute 46 seconds) and 3 minutes 57 seconds (2 minutes 11 seconds), respectively. Regression analyses revealed a trend for fewer overall verbal statements and fewer staff questions during peak periods, but no other significant differences for staff-caller communication behaviors were found. Peak activity for poison center call volume can be identified by statistical modeling. Calls during high volume periods were similar to low volume calls. Communication was more concise yet staff was able to maintain a good rapport with callers during busy call periods

Ultrasonic signal processing for sizing under-clad flaws

International Nuclear Information System (INIS)

Shankar, R.; Paradiso, T.J.; Lane, S.S.; Quinn, J.R.

1985-01-01

Ultrasonic digital data were collected from underclad cracks in sample pressure vessel specimen blocks. These blocks were weld cladded under different processes to simulate actual conditions in US Pressure Water Reactors. Each crack was represented by a flaw-echo dynamic curve which is a plot of the transducer motion on the surface as a function of the ultrasonic response into the material. Crack depth sizing was performed by identifying in the dynamic curve the crack tip diffraction signals from the upper and lower tips. This paper describes the experimental procedure, digital signal processing methods used and algorithms developed for crack depth sizing

Flawed Implementation or Inconsistent Logics? Lessons from Higher Education Reform in Ukraine

Science.gov (United States)

Shaw, Marta A.

2013-01-01

This article investigates two competing explanations of why reforms associated with the Bologna process brought disappointing results in Ukraine. The lack of anticipated benefits from the reforms may stem either from a flawed implementation of the Bologna process, or from more fundamental differences between the models of higher education…

High Production Volume Information System (HPVIS)

Data.gov (United States)

U.S. Environmental Protection Agency — The High Production Volume Information System (HPVIS) provides access to select health and environmental effect information on chemicals that are manufactured in...

Data analysis algorithms for flaw sizing based on eddy current rotating probe examination of steam generator tubes

International Nuclear Information System (INIS)

Bakhtiari, S.; Elmer, T.W.

2009-01-01

Computer-aided data analysis tools can help improve the efficiency and reliability of flaw sizing based on nondestructive examination data. They can further help produce more consistent results, which is important for both in-service inspection applications and for engineering assessments associated with steam generator tube integrity. Results of recent investigations at Argonne on the development of various algorithms for sizing of flaws in steam generator tubes based on eddy current rotating probe data are presented. The research was carried out as part of the activities under the International Steam Generator Tube Integrity Program (ISG-TIP) sponsored by the U.S. Nuclear Regulatory Commission. A computer-aided data analysis tool has been developed for off-line processing of eddy current inspection data. The main objectives of the work have been to a) allow all data processing stages to be performed under the same user interface, b) simplify modification and testing of signal processing and data analysis scripts, and c) allow independent evaluation of viable flaw sizing algorithms. The focus of most recent studies at Argonne has been on the processing of data acquired with the +Point probe, which is one of the more widely used eddy current rotating probes for steam generator tube examinations in the U.S. The probe employs a directional surface riding differential coil, which helps reduce the influence of tubing artifacts and in turn helps improve the signal-to-noise ratio. Various algorithms developed under the MATLAB environment for the conversion, segmentation, calibration, and analysis of data have been consolidated within a single user interface. Data acquired with a number of standard eddy current test equipment are automatically recognized and converted to a standard format for further processing. Because of its modular structure, the graphical user interface allows user-developed routines to be easily incorporated, modified, and tested independent of the

Ligament rupture and unstable burst behaviors of axial flaws in steam generator U-bends

Energy Technology Data Exchange (ETDEWEB)

Bahn, Chi Bum, E-mail: bahn@pusan.ac.kr [Pusan National University, 2 Busandaehak-ro 63 beon-gil, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Oh, Young-Jin [KEPCO Engineering & Construction Co. Inc., Seongnam 463-870 (Korea, Republic of); Majumdar, Saurin [Argonne National Laboratory, Lemont, IL 60439 (United States)

2015-11-15

Highlights: • Ligament rupture and unstable burst pressure tests were conducted with U-bends. • In general, U-bends showed higher ligament rupture and burst pressures than straight tubes. • U-bend test data was bounded by 90% lower limit of the probabilistic models for straight tubes. • Prediction models for straight tubes could be conservatively applied to U-bends. - Abstract: Incidents of U-bend cracking in steam generator (SG) tubes have been reported, some of which have led to tube rupture. Experimental and analytical modeling efforts to determine the failure criteria of flawed SG U-bends are limited. To evaluate structural integrity of flawed U-bends, ligament rupture and unstable burst pressure tests were conducted on 57 and 152 mm bend radius U-bends with axial electrical discharge machining notches. In general, the ligament rupture and burst pressures of the U-bends were higher than those of straight tubes with similar notches. To quantitatively address the test data scatter issue, probabilistic models were introduced. All ligament rupture and burst pressures of U-bends were bounded by 90% lower limits of the probabilistic models for straight tubes. It was concluded that the prediction models for straight tubes could be applied to U-bends to conservatively evaluate the ligament rupture and burst pressures of U-bends with axial flaws.

Ligament rupture and unstable burst behaviors of axial flaws in steam generator U-bends

International Nuclear Information System (INIS)

Bahn, Chi Bum; Oh, Young-Jin; Majumdar, Saurin

2015-01-01

Highlights: • Ligament rupture and unstable burst pressure tests were conducted with U-bends. • In general, U-bends showed higher ligament rupture and burst pressures than straight tubes. • U-bend test data was bounded by 90% lower limit of the probabilistic models for straight tubes. • Prediction models for straight tubes could be conservatively applied to U-bends. - Abstract: Incidents of U-bend cracking in steam generator (SG) tubes have been reported, some of which have led to tube rupture. Experimental and analytical modeling efforts to determine the failure criteria of flawed SG U-bends are limited. To evaluate structural integrity of flawed U-bends, ligament rupture and unstable burst pressure tests were conducted on 57 and 152 mm bend radius U-bends with axial electrical discharge machining notches. In general, the ligament rupture and burst pressures of the U-bends were higher than those of straight tubes with similar notches. To quantitatively address the test data scatter issue, probabilistic models were introduced. All ligament rupture and burst pressures of U-bends were bounded by 90% lower limits of the probabilistic models for straight tubes. It was concluded that the prediction models for straight tubes could be applied to U-bends to conservatively evaluate the ligament rupture and burst pressures of U-bends with axial flaws.

Advantages of using 192Ir γ-ray flaw detector for some products

International Nuclear Information System (INIS)

Qin Xiqi

1989-01-01

This paper describes the advantages of 192 Ir γ-ray flaw detector made in China in welding seam testings. The authors made a comparison between 192 Ir γ-ray and X-ray machine. 192 Ir γ-ray machine showed many advantages, such as shorter working hours and less labour intensity

Development of automatic flaw detection systems for magnetic particle examination

International Nuclear Information System (INIS)

Shirai, T.; Kimura, J.; Amako, T.

1988-01-01

Utilizing a video camera and an image processor, development was carried out on automatic flaw detection and discrimination techniques for the purpose of achieving automated magnetic particle examination. Following this, fluorescent wet magnetic particle examination systems for blade roots and rotor grooves of turbine rotors and the non-fluorescent dry magnetic particle examination system for butt welds, were developed. This paper describes these automatic magnetic particle examination (MT) systems and the functional test results

High tidal volume ventilation in infant mice.

Science.gov (United States)

Cannizzaro, Vincenzo; Zosky, Graeme R; Hantos, Zoltán; Turner, Debra J; Sly, Peter D

2008-06-30

Infant mice were ventilated with either high tidal volume (V(T)) with zero end-expiratory pressure (HVZ), high V(T) with positive end-expiratory pressure (PEEP) (HVP), or low V(T) with PEEP. Thoracic gas volume (TGV) was determined plethysmographically and low-frequency forced oscillations were used to measure the input impedance of the respiratory system. Inflammatory cells, total protein, and cytokines in bronchoalveolar lavage fluid (BALF) and interleukin-6 (IL-6) in serum were measured as markers of pulmonary and systemic inflammatory response, respectively. Coefficients of tissue damping and tissue elastance increased in all ventilated mice, with the largest rise seen in the HVZ group where TGV rapidly decreased. BALF protein levels increased in the HVP group, whereas serum IL-6 rose in the HVZ group. PEEP keeps the lungs open, but provides high volumes to the entire lungs and induces lung injury. Compared to studies in adult and non-neonatal rodents, infant mice demonstrate a different response to similar ventilation strategies underscoring the need for age-specific animal models.

Design of Tunnel Magnetoresistive-Based Circular MFL Sensor Array for the Detection of Flaws in Steel Wire Rope

Directory of Open Access Journals (Sweden)

Liu Xiucheng

2016-01-01

Full Text Available Tunnel magnetoresistive (TMR devices have superior performances in weak magnetic field detection. In this study, TMR devices were first employed to form a circular magnetic flux leakage (MFL sensor for slight wire rope flaw detection. Two versions of this tailor-made circular TMR-based sensor array were presented for the inspection of wire ropes with the diameters of 14 mm and 40 mm, respectively. Helmholtz-like coils or a ferrite magnet-based magnetizer was selected to provide the proper magnetic field, in order to meet the technical requirements of the TMR devices. The coefficient of variance in the flaw detection performance of the sensor array elements was experimentally estimated at 4.05%. Both versions of the MFL sensor array were able to detect multiple single-broken wire flaws in the wire ropes. The accurate axial and circumferential positions of these broken wire flaws were estimated from the MFL scanning image results. In addition, the proposed TMR-based sensor array was applied to detect the MFL signal induced by slight surface wear defects. A mutual correlation analysis method was used to distinguish the signals caused by the lift-off fluctuation from the MFL scanning image results. The MFL sensor arrays presented in this study provide inspiration for the designing of tailor-made TMR-based circular sensor arrays for cylindrical ferromagnetic structural inspections.

The Flaws of Fragmented Financial Standard Setting

DEFF Research Database (Denmark)

Mügge, Daniel; Perry, James

2014-01-01

rating, accounting, and derivatives trading, this article demonstrates why the appropriateness of the organizational architecture of global financial governance is necessarily contingent upon one’s understanding of how financial markets work. In particular, if financial markets are not anchored......In the half decade following the 2007 financial crisis, the reform of global financial governance was driven by two separate policy debates: one on the substantive content of regulations, the other on the organizational architecture of their governance. The separation of the two debates among...... policymakers has been mirrored in academia, where postcrisis analyses of financial governance have remained detached from reinvigorated discussions about the nature of financial markets. We argue that this separation is deeply flawed. Presenting an analysis of interactions between standards for banking, credit...

PowerPoint® Presentation Flaws and Failures: A Psychological Analysis

Directory of Open Access Journals (Sweden)

Stephen Michael Kosslyn

2012-07-01

Full Text Available Electronic slideshow presentations are often faulted anecdotally, but little empirical work has documented their faults. Three studies reported here document psychological causes of their flaws. In Study 1 we found that eight psychological principles are often violated in PowerPoint® presentations, across different fields—for example, academic research presentations generally were no better or worse than business presentations. In Study 2 we found that respondents reported having noticed, and having been annoyed by, specific problems in presentations arising from violations of particular psychological principles. Finally, in Study 3 we showed that observers are not highly accurate in recognizing when slides violated a specific psychological rule. Furthermore, even when they correctly identified the violation, they often could not explain the nature of the problem. In sum, the psychological foundations for effective slideshow presentation design are neither obvious nor necessarily intuitive, and presentation designers in all fields, from education to business to government, could benefit from explicit instruction in relevant aspects of psychology.

Design of Friction Stir Welding Tool for Avoiding Root Flaws.

Science.gov (United States)

Ji, Shude; Xing, Jingwei; Yue, Yumei; Ma, Yinan; Zhang, Liguo; Gao, Shuangsheng

2013-12-12

In order to improve material flow behavior during friction stir welding and avoid root flaws of weld, a tool with a half-screw pin and a tool with a tapered-flute pin are suggested. The effect of flute geometry in tool pins on material flow velocity is investigated by the software ANSYS FLUENT. Numerical simulation results show that high material flow velocity appears near the rotational tool and material flow velocity rapidly decreases with the increase of distance away from the axis of the tool. Maximum material flow velocity by the tool with the tapered-flute pin appears at the beginning position of flute and the velocity decreases with the increase of flow length in flute. From the view of increasing the flow velocity of material near the bottom of the workpiece or in the middle of workpiece, the tool with the half-screw pin and the tool with the tapered-flute pin are both better than the conventional tool.

Elastodynamic models for extending GTD to penumbra and finite size flaws

International Nuclear Information System (INIS)

Djakou, A Kamta; Darmon, M; Potel, C

2016-01-01

The scattering of elastic waves from an obstacle is of great interest in ultrasonic Non Destructive Evaluation (NDE). There exist two main scattering phenomena: specular reflection and diffraction. This paper is especially focused on possible improvements of the Geometrical Theory of Diffraction (GTD), one classical method used for modelling diffraction from scatterer edges. GTD notably presents two important drawbacks: it is theoretically valid for a canonical infinite edge and not for a finite one and presents discontinuities around the direction of specular reflection. In order to address the first drawback, a 3D hybrid method using both GTD and Huygens secondary sources has been developed to deal with finite flaws. ITD (Incremental Theory of Diffraction), a method developed in electromagnetism, has also been developed in elastodynamics to deal with small flaws. Experimental validation of these methods has been performed. As to the second drawback, a GTD uniform correction, the UTD (Uniform Theory of Diffraction) has been developed in the view of designing a generic model able to correctly simulate both specular reflection and diffraction. A comparison has been done between UTD numerical results and UAT (Uniform Asymptotic Theory of Diffraction) which is another uniform solution of GTD. (paper)

Detection and assessment of flaws in friction stir welded joints using ultrasonic guided waves: experimental and finite element analysis

Science.gov (United States)

Fakih, Mohammad Ali; Mustapha, Samir; Tarraf, Jaafar; Ayoub, Georges; Hamade, Ramsey

2018-02-01

Ultrasonic guided waves (GWs), e.g. Lamb waves, have been proven effective in the detection of defects such as corrosion, cracking, delamination, and debonding in both composite and metallic structures. They are a significant tool employed in structural health monitoring. In this study, the ability of ultrasonic GWs to assess the quality of friction stir welding (FSW) was investigated. Four friction stir welded AZ31B magnesium plates processed with different welding parameters and a non-welded plate were used. The fundamental symmetric (S0) Lamb wave mode was excited using piezoelectric wafers (PZTs). Further, the S0 mode was separated using the "Improved complete ensemble empirical mode decomposition with adaptive noise (Improved CEEMDAN)" technique. A damage index (DI) was defined based on the variation in the amplitude of the captured wave signals in order to detect the presence and asses the severity of damage resulting from the welding process. As well, computed tomography (CT) scanning was used as a non-destructive testing (NDT) technique to assess the actual weld quality and validate predictions based on the GW approach. The findings were further confirmed using finite element analysis (FEA). To model the actual damage profile in the welds, "Mimics" software was used for the 3D reconstruction of the CT scans. The built 3D models were later used for evaluation of damage volume and for FEA. The damage volumes were correlated to the damage indices computed from both experimental and numerical data. The proposed approach showed high sensitivity of the S0 mode to internal flaws within the friction stir welded joints. This methodology has great potential as a future classification method of FSW quality.

Program to develop acoustic emission: flaw relationship for inservice monitoring of nuclear pressure vessels. Progress report No. 1, July 1, 1976--February 1, 1977

International Nuclear Information System (INIS)

Hutton, P.H.; Schwenk, E.B.

1977-03-01

This is a laboratory research program to characterize acoustic emission (AE) from flaw growth and noise from innocuous sources in A533B Class 1 pressure vessel steel. The objectives are: characterize AE from a limited range of defects and material property conditions of concern to reactor pressure vessel integrity; characterize AE from innocuous sources (including defects); develop criteria for distinguishing significant flaws from innocuous sources; and develop an AE flaw damage model to serve as a basis for relating in-service AE to pressure vessel integrity. The purpose of the program is to build an experimental evaluation of the feasibility of detecting and analyzing flaw growth in reactor pressure boundaries by continuously monitoring for AE. A detailed program plan in the form of an analysis-before-test document has been prepared and approved

Insensitivity to Flaws Leads to Damage Tolerance in Brittle Architected Meta-Materials

Science.gov (United States)

Montemayor, L. C.; Wong, W. H.; Zhang, Y.-W.; Greer, J. R.

2016-02-01

Cellular solids are instrumental in creating lightweight, strong, and damage-tolerant engineering materials. By extending feature size down to the nanoscale, we simultaneously exploit the architecture and material size effects to substantially enhance structural integrity of architected meta-materials. We discovered that hollow-tube alumina nanolattices with 3D kagome geometry that contained pre-fabricated flaws always failed at the same load as the pristine specimens when the ratio of notch length (a) to sample width (w) is no greater than 1/3, with no correlation between failure occurring at or away from the notch. Samples with (a/w) > 0.3, and notch length-to-unit cell size ratios of (a/l) > 5.2, failed at a lower peak loads because of the higher sample compliance when fewer unit cells span the intact region. Finite element simulations show that the failure is governed by purely tensile loading for (a/w) meta-materials may give rise to their damage tolerance and insensitivity of failure to the presence of flaws even when made entirely of intrinsically brittle materials.

Effective moduli of high volume fraction particulate composites

International Nuclear Information System (INIS)

Kwon, P.; Dharan, C.K.H.

1995-01-01

Predictions using current micromechanics theories for the effective moduli of particulate-reinforced composites tend to break down at high volume fractions of the reinforcing phase. The predictions are usually well below experimentally measured values of the Young's modulus for volume fractions exceeding about 0.6. In this paper, the concept of contiguity, which is a measure of phase continuity, is applied to Mori-Tanaka micromechanics theory. It is shown that contiguity of the second phase increases with volume fraction, leading eventually to a reversal in the roles of the inclusion and matrix. In powder metallurgy practice, it is well known that at high volume fractions, sintering and consolidation of the reinforcement make it increasingly continuous and more like the matrix phase, while the former matrix tends to become more like the inclusion phase. The concept of contiguity applied to micromechanics theory results in very good agreement between the predicted Young's modulus and experimental data on tungsten carbide particulate-reinforced cobalt

Study on the High Volume Reduction of Radioactive Wastes

Energy Technology Data Exchange (ETDEWEB)

Kim, Ki Hong; Sik, Kang Il; Seok, Hong Dae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Ho, Jeon Gil [RADIN Co. Ltd., Daejeon (Korea, Republic of)

2013-10-15

The solidification of radioactive wastes by the mixing method always increases their volume due to the limitation of incorporation ratio (waste/solidification agent). But if the powdered wastes can be compacted as the high density pellets and also the pellets can be filled up in a waste drum as much as possible while solidifying them with a very sticky solidification agent including a void formed in the filling step of pellets, it might be more desirable to reduce the waste volume as compared with the mixing method. So in this study, we designed and manufactured a high volume reduction machine which has the special size and shape of a pellet pocket, which the pellets can be extracted from easily and filled up in a large amount in drum, a pressurizing device to press 2 rolls, and the uniform feeding device of powder to the roll tyre. Some operational parameters which affect the formation of pellets from a powder were investigated, and then the volume reduction of a powder was evaluated. The briquetting machine, popular in general industry, was modified to apply for the volume reduction of the powered radioactive wastes (dried concentrate, sludge, spent ion-exchange resin, ash, depleted uranium powder, and etc.). In this developed high volume reduction machine, the capacity was 25 ∼ 62.5 kg/h at the optimum conditions, and the estimated volume reduction was about 2.95 (2.74/0.93) on the basis of between a powder (bulk density = 0.93 g/cm{sup 3}) and the pellet (2.74 g/cm{sup 3}). But on the basis of 200L drum, the calculated volume reduction was about 1.34 in consideration of a void volume originated in the filling step of the pellets.

OCA-II, a code for calculating the behavior of 2-D and 3-D surface flaws in a pressure vessel subjected to temperature and pressure transients

International Nuclear Information System (INIS)

Ball, D.G.; Drake, J.B.; Cheverton, R.D.; Iskander, S.K.

1984-02-01

The OCA-II computer code, like its predecessor OCA-I, performs the thermal, stress, and linear elastic fracture-mechanics analysis for long flaws on the surface of a cylinder that is subjected to thermal and pressure transients. OCA-II represents a revised and expanded version of OCA-I and includes as new features (1) cladding as a discrete region, (2) a finite-element subroutine for calculating the stresses, and (3) the ability to calculate stress intensity factors for certain three-dimensional flaws, for two-dimensional circumferential flaws on the inner surface, and for both axial and circumferential flaws on the outer surface. OCA-I considered only inner-surface flaws. An option is included in OCA-II that permits a search for critical values of fluence or nil-ductility reference temperature corresponding to a specified failure criterion. These and other features of OCA-II are described in the report, which also includes user instructions for the code

Low and high frequency asymptotics acoustic, electromagnetic and elastic wave scattering

CERN Document Server

Varadan, VK

2013-01-01

This volume focuses on asymptotic methods in the low and high frequency limits for the solution of scattering and propagation problems. Each chapter is pedagogical in nature, starting with the basic foundations and ending with practical applications. For example, using the Geometrical Theory of Diffraction, the canonical problem of edge diffraction is first solved and then used in solving the problem of diffraction by a finite crack. In recent times, the crack problem has been of much interest for its applications to Non-Destructive Evaluation (NDE) of flaws in structural materials.

Self-propelled x-ray flaw detector

International Nuclear Information System (INIS)

Ershov, L.S.; Krasilnikov, S.B.; Lozovoi, L.N.; Losev, J.F.; Morgovsky, L.Y.; Pelix, E.A.; Khakimyanov, R.R.

1988-01-01

A self-propelled X-ray flaw detector for radiographic inspection of welded joints in pipelines comprises a carriage mounting a motor, a detector having two Geiger counters, a pulsed X-ray generator, and an exposure and carriage electronic control system. A memory unit in the control system has four storage elements containing information about the motion of the carriage. As the carriage moves in direction A, first one and then the other of the Geiger counters receives radiation from an isotope source positioned near a joint, and by means of logic circuitry in the control system, the information in the storage elements is modified to stop the carriage and to operate a timer to expose the weld. During exposure the X-rays may interfere with the information in the storage elements, but by means of a square-wave generator and the logic circuitry, the stored information is correctly reset in order to eliminate false operation of the memory unit. (author)

High lung volume increases stress failure in pulmonary capillaries

Science.gov (United States)

Fu, Z.; Costello, M. L.; Tsukimoto, K.; Prediletto, R.; Elliott, A. R.; Mathieu-Costello, O.; West, J. B.

1992-01-01

We previously showed that when pulmonary capillaries in anesthetized rabbits are exposed to a transmural pressure (Ptm) of approximately 40 mmHg, stress failure of the walls occurs with disruption of the capillary endothelium, alveolar epithelium, or sometimes all layers. The present study was designed to test whether stress failure occurred more frequently at high than at low lung volumes for the same Ptm. Lungs of anesthetized rabbits were inflated to a transpulmonary pressure of 20 cmH2O, perfused with autologous blood at 32.5 or 2.5 cmH2O Ptm, and fixed by intravascular perfusion. Samples were examined by both transmission and scanning electron microscopy. The results were compared with those of a previous study in which the lung was inflated to a transpulmonary pressure of 5 cmH2O. There was a large increase in the frequency of stress failure of the capillary walls at the higher lung volume. For example, at 32.5 cmH2O Ptm, the number of endothelial breaks per millimeter cell lining was 7.1 +/- 2.2 at the high lung volume compared with 0.7 +/- 0.4 at the low lung volume. The corresponding values for epithelium were 8.5 +/- 1.6 and 0.9 +/- 0.6. Both differences were significant (P less than 0.05). At 52.5 cmH2O Ptm, the results for endothelium were 20.7 +/- 7.6 (high volume) and 7.1 +/- 2.1 (low volume), and the corresponding results for epithelium were 32.8 +/- 11.9 and 11.4 +/- 3.7. At 32.5 cmH2O Ptm, the thickness of the blood-gas barrier was greater at the higher lung volume, consistent with the development of more interstitial edema. Ballooning of the epithelium caused by accumulation of edema fluid between the epithelial cell and its basement membrane was seen at 32.5 and 52.5 cmH2O Ptm. At high lung volume, the breaks tended to be narrower and fewer were oriented perpendicular to the axis of the pulmonary capillaries than at low lung volumes. Transmission and scanning electron microscopy measurements agreed well. Our findings provide a physiological

High Volume Manufacturing and Field Stability of MEMS Products

Science.gov (United States)

Martin, Jack

Low volume MEMS/NEMS production is practical when an attractive concept is implemented with business, manufacturing, packaging, and test support. Moving beyond this to high volume production adds requirements on design, process control, quality, product stability, market size, market maturity, capital investment, and business systems. In a broad sense, this chapter uses a case study approach: It describes and compares the silicon-based MEMS accelerometers, pressure sensors, image projection systems, and gyroscopes that are in high volume production. Although they serve several markets, these businesses have common characteristics. For example, the manufacturing lines use automated semiconductor equipment and standard material sets to make consistent products in large quantities. Standard, well controlled processes are sometimes modified for a MEMS product. However, novel processes that cannot run with standard equipment and material sets are avoided when possible. This reliance on semiconductor tools, as well as the organizational practices required to manufacture clean, particle-free products partially explains why the MEMS market leaders are integrated circuit manufacturers. There are other factors. MEMS and NEMS are enabling technologies, so it can take several years for high volume applications to develop. Indeed, market size is usually a strong function of price. This becomes a vicious circle, because low price requires low cost - a result that is normally achieved only after a product is in high volume production. During the early years, IC companies reduced cost and financial risk by using existing facilities for low volume MEMS production. As a result, product architectures are partially determined by capabilities developed for previous products. This chapter includes a discussion of MEMS product architecture with particular attention to the impact of electronic integration, packaging, and surfaces. Packaging and testing are critical, because they are

Reliability assessment of hydraulic cylinders considering service loads and flaw distribution

International Nuclear Information System (INIS)

Altamura, Alessandra; Beretta, Stefano

2012-01-01

Manufacturing process, service conditions and material properties are all necessary requirements to a good design of tubular mechanical components subjected to fatigue. The most common approach to this design is usually deterministic, where a fixed NDT threshold, related to flaw acceptance limit, is set. However many uncertainties are left aside, i.e. the failure probability related to the fatigue strength under applied loads. This paper addresses the reliability evaluation of tubular mechanical components carrying some flaws and subjected to cyclic internal pressure variation. The aim is comparing the probability of failure obtained under several assumptions. A reliability assessment model, based on a random variable approach, has been implemented by using the Monte Carlo method. The analysis of the results, from a case study based on load spectra measurements of hydraulic cylinders of earth moving machines, has consented to evaluate the most important factors influencing the fatigue life prediction of these components. Highlights: ► Reliability evaluation of tubular components subjected to variable internal pressure. ► The dispersion of the threshold controls the stochasticity of crack growth. ► A random variable model has been developed using Monte Carlo. ► Initial crack size and spectrum shape are key factors in reliability evaluation.

An Experimental Study of High Strength-High Volume Fly Ash Concrete for Sustainable Construction Industry

Science.gov (United States)

Kate, Gunavant K.; Thakare, Sunil B., Dr.

2017-08-01

Concrete is the most widely used building material in the construction of infrastructures such as buildings, bridges, highways, dams, and many other facilities. This paper reports the development, the basic idea, the main properties of high strength-high volume fly ash with application in concrete associated with the development and implementation of Sustainable Properties of High Volume Fly Ash Concrete (HVFAC) Mixtures and Early Age Shrinkage and mechanical properties of concrete for 7,28,56 and 90days. Another alternative to make environment-friendly concrete is the development of high strength-high-volume fly ash concrete which is an synthesized from materials of geological origin or by-product materials such as fly ash which is rich in silicon and aluminum. In this paper 6 concrete mixtures were produced to evaluate the effect of key parameters on the mechanical properties of concrete and its behavior. The study key parameters are; binder material content, cement replacement ratios, and the steel fibers used to High Volume Fly Ash mixtures for increasing performance of concrete.

Does an inter-flaw length control the accuracy of rupture forecasting in geological materials?

Science.gov (United States)

Vasseur, Jérémie; Wadsworth, Fabian B.; Heap, Michael J.; Main, Ian G.; Lavallée, Yan; Dingwell, Donald B.

2017-10-01

Multi-scale failure of porous materials is an important phenomenon in nature and in material physics - from controlled laboratory tests to rockbursts, landslides, volcanic eruptions and earthquakes. A key unsolved research question is how to accurately forecast the time of system-sized catastrophic failure, based on observations of precursory events such as acoustic emissions (AE) in laboratory samples, or, on a larger scale, small earthquakes. Until now, the length scale associated with precursory events has not been well quantified, resulting in forecasting tools that are often unreliable. Here we test the hypothesis that the accuracy of the forecast failure time depends on the inter-flaw distance in the starting material. We use new experimental datasets for the deformation of porous materials to infer the critical crack length at failure from a static damage mechanics model. The style of acceleration of AE rate prior to failure, and the accuracy of forecast failure time, both depend on whether the cracks can span the inter-flaw length or not. A smooth inverse power-law acceleration of AE rate to failure, and an accurate forecast, occurs when the cracks are sufficiently long to bridge pore spaces. When this is not the case, the predicted failure time is much less accurate and failure is preceded by an exponential AE rate trend. Finally, we provide a quantitative and pragmatic correction for the systematic error in the forecast failure time, valid for structurally isotropic porous materials, which could be tested against larger-scale natural failure events, with suitable scaling for the relevant inter-flaw distances.

Fitness-for-service and decisions for petroleum and chemical equipment. PVP-Volume 315

International Nuclear Information System (INIS)

Prager, M.; Becht, C. IV; Depadova, T.A.; Okazaki, M.; Onyewuenyi, O.A.; Smith, J.P.; Takezono, S.; Weingart, L.J.; Yagi, K.

1995-01-01

This volume is part of a series of publications intended to present the technical foundation for broadly accepted practices to establish the mechanical integrity of equipment in service. A focal point for this activity has been a Materials Properties Council program on fitness-for-service (FSS) reported in earlier PVP volumes. Work reported here covers the full range of equipment of interest to petroleum and chemical companies from LNG to creep service and provides a snapshot of current Codes, methods, concerns, and problems. It encompasses crack-like flaws and local thinning situations, welds, clad vessels, storage tanks, and pressure vessels. The work in progress is only a start, and the papers herein should be viewed as part of the process of validating the techniques used. While most of the applications are to petroleum refineries and natural gas processing plants, some papers deal with fossil-fuel power plants, nuclear power plants, synthetic fuels refineries, and materials for high-temperature applications. Papers have been processed separately for inclusion on the data base

Acoustic Emission Behavior of Rock-Like Material Containing Two Flaws in the Process of Deformation Failure

Directory of Open Access Journals (Sweden)

Quan-Sheng Liu

2015-01-01

Full Text Available Many sudden disasters (such as rock burst by mining extraction originate in crack initiation and propagation. Meanwhile a large number of shock waves are produced by rock deformation and failure. With the purpose of investigating crack coalescence and failure mechanism in rock, experimental research of rock-like materials with two preexisting flaws was performed. Moreover, the AE technique and photographic monitoring were adopted to clarify further the procedure of the crack coalescence and failure. It reveals that AE location technique can record the moments of crack occurrences and follow the crack growth until final failure. Finally, the influence of different flaw geometries on crack initiation strength is analyzed in detail. This research provides increased understanding of the fracture mechanism of mining-induced disasters.

High volume improves outcomes: The argument for centralization of rectal cancer surgery.

Science.gov (United States)

Aquina, Christopher T; Probst, Christian P; Becerra, Adan Z; Iannuzzi, James C; Kelly, Kristin N; Hensley, Bradley J; Rickles, Aaron S; Noyes, Katia; Fleming, Fergal J; Monson, John R T

2016-03-01

Centralization of care to "centers of excellence" in Europe has led to improved oncologic outcomes; however, little is known regarding the impact of nonmandated regionalization of rectal cancer care in the United States. The Statewide Planning and Research Cooperative System (SPARCS) was queried for elective abdominoperineal and low anterior resections for rectal cancer from 2000 to 2011 in New York with the use of International Classification of Diseases, Ninth Revision codes. Surgeon volume and hospital volume were grouped into quartiles, and high-volume surgeons (≥ 10 resections/year) and hospitals (≥ 25 resections/year) were defined as the top quartile of annual caseload of rectal cancer resection and compared with the bottom 3 quartiles during analyses. Bivariate and multilevel regression analyses were performed to assess factors associated with restorative procedures, 30-day mortality, and temporal trends in these endpoints. Among 7,798 rectal cancer resections, the overall rate of no-restorative proctectomy and 30-day mortality decreased by 7.7% and 1.2%, respectively, from 2000 to 2011. In addition, there was a linear increase in the proportion of cases performed by both high-volume surgeons and high-volume hospitals and a decrease in the number of surgeons and hospitals performing rectal cancer surgery. High-volume surgeons at high-volume hospitals were associated independently with both less nonrestorative proctectomies (odds ratio 0.65, 95% confidence interval 0.48-0.89) and mortality (odds ratio 0.43, 95% confidence interval 0.21-0.87) rates. No patterns of significant improvement within the volume strata of the surgeon and hospitals were observed over time. This study suggests that the current trend toward regionalization of rectal cancer care to high-volume surgeons and high-volume centers has led to improved outcomes. These findings have implications regarding the policy of health care delivery in the United States, supporting referral to high-volume

Unsupervised Learning Through Randomized Algorithms for High-Volume High-Velocity Data (ULTRA-HV).

Energy Technology Data Exchange (ETDEWEB)

Pinar, Ali [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kolda, Tamara G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Carlberg, Kevin Thomas [Wake Forest Univ., Winston-Salem, MA (United States); Ballard, Grey [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mahoney, Michael [Univ. of California, Berkeley, CA (United States)

2018-01-01

Through long-term investments in computing, algorithms, facilities, and instrumentation, DOE is an established leader in massive-scale, high-fidelity simulations, as well as science-leading experimentation. In both cases, DOE is generating more data than it can analyze and the problem is intensifying quickly. The need for advanced algorithms that can automatically convert the abundance of data into a wealth of useful information by discovering hidden structures is well recognized. Such efforts however, are hindered by the massive volume of the data and its high velocity. Here, the challenge is developing unsupervised learning methods to discover hidden structure in high-volume, high-velocity data.

Accomplishments: AE characterization program for remote flaw evaluation

International Nuclear Information System (INIS)

Hutton, P.H.; Schwenk, E.B.; Kurtz, R.J.

1978-01-01

The purpose of the program is to develop an experimental/analytical evaluation of the feasibility of detecting and analyzing flaw growth in reactor pressure boundaries by means of continuously monitoring acoustic emission (AE). The investigation is devoted exclusively to ASTM Type A533, Grade B, Class 1 material. The basic approach to interpretive model development is through laboratory testing of 1 to 1 1 / 2 inch (25.4 to 38 mm) thick fracture mechanics specimens in both fatigue and fracture at both room temperature and 550 0 F (288 0 C). Seven parameters are measured for each AE signal and related to fracture mechanics functions. AE data from fracture testing of 6 inch (152 mm) wall pressure vessels are also incorporated in analysis

Ribbon scanning confocal for high-speed high-resolution volume imaging of brain.

Directory of Open Access Journals (Sweden)

Alan M Watson

Full Text Available Whole-brain imaging is becoming a fundamental means of experimental insight; however, achieving subcellular resolution imagery in a reasonable time window has not been possible. We describe the first application of multicolor ribbon scanning confocal methods to collect high-resolution volume images of chemically cleared brains. We demonstrate that ribbon scanning collects images over ten times faster than conventional high speed confocal systems but with equivalent spectral and spatial resolution. Further, using this technology, we reconstruct large volumes of mouse brain infected with encephalitic alphaviruses and demonstrate that regions of the brain with abundant viral replication were inaccessible to vascular perfusion. This reveals that the destruction or collapse of large regions of brain micro vasculature may contribute to the severe disease caused by Venezuelan equine encephalitis virus. Visualization of this fundamental impact of infection would not be possible without sampling at subcellular resolution within large brain volumes.

A comparative study of self-consolidating concretes incorporating high-volume natural pozzolan or high-volume fly ash

KAUST Repository

Celik, Kemal; Meral, Cagla; Mancio, Mauricio; Mehta, P. Kumar; Monteiro, Paulo J.M.

2014-01-01

The purpose of this study is to compare the effects of Portland cement replacement on the strength and durability of self-consolidating concretes (SSC). The two replacement materials used are high-volume natural pozzolan (HVNP), a Saudi Arabian aluminum-silica rich basaltic glass and high-volume Class-F fly ash (HVFAF), from Jim Bridger Power Plant, Wyoming, US. As an extension of the study, limestone filler (LF) is also used to replace Portland cement, alongside HVNP or HVFAF, forming ternary blends. Along with compressive strength tests, non-steady state chloride migration and gas permeability tests were performed, as durability indicators, on SCC specimens. The results were compared to two reference concretes; 100% ordinary Portland cement (OPC) and 85% OPC - 15% LF by mass. The HVNP and HVFAF concrete mixes showed strength and durability results comparable to those of the reference concretes; identifying that both can effectively be used to produce low-cost and environmental friendly SCC. © 2013 Elsevier Ltd. All rights reserved.

A comparative study of self-consolidating concretes incorporating high-volume natural pozzolan or high-volume fly ash

KAUST Repository

Celik, Kemal

2014-09-01

The purpose of this study is to compare the effects of Portland cement replacement on the strength and durability of self-consolidating concretes (SSC). The two replacement materials used are high-volume natural pozzolan (HVNP), a Saudi Arabian aluminum-silica rich basaltic glass and high-volume Class-F fly ash (HVFAF), from Jim Bridger Power Plant, Wyoming, US. As an extension of the study, limestone filler (LF) is also used to replace Portland cement, alongside HVNP or HVFAF, forming ternary blends. Along with compressive strength tests, non-steady state chloride migration and gas permeability tests were performed, as durability indicators, on SCC specimens. The results were compared to two reference concretes; 100% ordinary Portland cement (OPC) and 85% OPC - 15% LF by mass. The HVNP and HVFAF concrete mixes showed strength and durability results comparable to those of the reference concretes; identifying that both can effectively be used to produce low-cost and environmental friendly SCC. © 2013 Elsevier Ltd. All rights reserved.

Intentionally Flawed Manuscripts as Means for Teaching Students to Critically Evaluate Scientific Papers

Science.gov (United States)

Ferenc, Jaroslav; Cervenák, Filip; Bircák, Erik; Juríková, Katarína; Goffová, Ivana; Gorilák, Peter; Huraiová, Barbora; Plavá, Jana; Demecsová, Loriana; Duríková, Nikola; Galisová, Veronika; Gazdarica, Matej; Puškár, Marek; Nagy, Tibor; Nagyová, Sona; Mentelová, Lucia; Slaninová, Miroslava; Ševcovicová, Andrea; Tomáška, Lubomír

2018-01-01

As future scientists, university students need to learn how to avoid making errors in their own manuscripts, as well as how to identify flaws in papers published by their peers. Here we describe a novel approach on how to promote students' ability to critically evaluate scientific articles. The exercise is based on instructing teams of students to…

High speed analysis of high pressure combustion in a constant volume cell

NARCIS (Netherlands)

Frijters, P.J.M.; Klein-Douwel, R.J.H.; Manski, S.S.; Somers, L.M.T.; Baert, R.S.G.; Dias, V.

2005-01-01

A combustion process with N2, O2 and C2H4 as fuel used in an opticallyaccessible, high pressure, high temperature, constant volume cell forresearch on diesel fuel spray formation, is studied. The flame frontspeed Vf,HS is determined using high speed imaging. The pressure traceof the combustion

Indigenous high volume air sampler

International Nuclear Information System (INIS)

Kotrappa, P.; Setty, N.P.N.; Raghunath, B.; Sivasubrahmanyam, P.S.

1978-01-01

A high volume air sampler for use in assessing concentrations of low levels of air borne particulates has been fabricated. The sampler will be of use in radioactive installations, conventional industries and environmental pollution analysis. It is comparable in performance with the imported Staplex air samplers. A turbine and motor system similar to the one found in conventional vacuum cleaners is used in its design. The sampler units can be produced in large numbers. (M.G.B.)

Evaluation of flaws or service induced cracks in pressure vessels

International Nuclear Information System (INIS)

Riccardella, P.C.; Copeland, J.F.; Gilman, J.

1987-01-01

An overview of the ASME flaw evaluation procedures for nuclear pressure vessels is presented, with emphasis on fatigue crack growth evaluations. Environmental and load-rate effects are further considered with respect to new crack growth data and a time-dependent crack growth model. This new crack growth model is applied to evaluate feedwater nozzle cracking in boiling water reactors and is compared to current and past ASME crack growth curves. The time-dependent model bounds the observed cracking and indicates that more detailed consideration of material susceptibility, in terms of sulfur content and product form, is needed

MILITARY RESEARCH: Researchers Target Flaws in Ballistic Missile Defense Plan.

Science.gov (United States)

Malakoff, D; Cho, A

2000-06-16

More than three dozen scientists journeyed to Washington, D.C., this week to warn lawmakers that a proposed $60 billion U.S. missile defense system, designed to knock incoming warheads out of the sky, is technically flawed because it can't pick out real warheads from decoys. Pentagon officials heatedly deny a new report by one scientist that contractors have rigged trials to hide the problem, although they admit that some tests were simplified to save time. In the wake of these events, a leading Democrat is urging President Bill Clinton to delay a pending decision on building the system.

A procedure to detect flaws inside large size marble blocks by ultrasound

OpenAIRE

Bramanti, Mauro; Bozzi, Edoardo

1999-01-01

In stone and marble industry there is considerable interest in the possibility of using ultrasound diagnostic techniques for non-destructive testing of large size blocks in order to detect internal flaws such as faults, cracks and fissures. In this paper some preliminary measurements are reported in order to acquire basic knowledge of the fundamental properties of ultrasound, such as propagation velocity and attenuation, in the media here considered. We then outline a particular diagnostic pr...

The shallow flaw effect and the local approach to cleavage fracture

International Nuclear Information System (INIS)

Moinereau, D.

1996-10-01

The capability of Beremin model to explain the shallow flaw effect in cleavage fracture is evaluated. Numerous two-dimensional finite element calculations are performed on several cracked specimens (cladded and un-cladded specimens with different values of a/W ratio) submitted to mechanical or thermal loading. The behavior of different specimens is examined using the Weibull stress σ w versus stress intensity factor K J curves. The stress fields and plastic zones at the crack tip are also compared on respective cracked specimens. (K.A.)

Flaw behavior in mechanically loaded clad plates

International Nuclear Information System (INIS)

Iskander, S.K.; Robinson, G.C.; Oland, C.B.

1989-01-01

A small crack near the inner surface of clad nuclear reactor pressure vessels is an important consideration in the safety assessment of the structural integrity of the vessel. Four-point bend tests on large plate specimens, conforming to ASTM specification for pressure vessel plates, alloy steels, quenched and tempered, Mn-Mo and Mn-Mo-Ni (A533) grade B six clad and two unclad with stainless steels 308, 309 and 312 weld wires, were performed to determine the effect of cladding upon the propagation of small surface cracks subjected to stress states. Results indicated that the tough surface layer composed of cladding and/or heat-affected zone has enhanced the load-bearing capacity of plates under conditions where unclad plates have ruptured. The results are interpreted in terms of fracture mechanics. The behavior of flaws in clad reactor pressure vessels is examined in the light of the test results. 11 refs., 8 figs., 2 tabs

SCC with high volume of fly ash content

Directory of Open Access Journals (Sweden)

Bakhrakh Anton

2017-01-01

Full Text Available Self-compacting concrete is a very perspective building material. It provides great benefits during the construction of heavily reinforced buildings. SCC has outstanding properties such as high flowability, dense structure and high strength due to specific quality of aggregates, fillers, their proportion in mix, use of polycarboxylate-based superplasticizers. Main disadvantages of SCC are high price and the difficulty of obtaining a proper mix. Use of fillers, such as fly ash type F, is a way to make SCC cheaper by replacing part of cement. Fly ash also provides some technological and operating advantages. In this paper the influence of high volume (60% from cement fly ash type F on the properties of concrete mixture and hardened concrete is investigated. The result of the work shows the possibility of reduction the cost of SCC using ordinary fillers and high amount of fly ash. The investigated SCC has low speed of hardening (7-day compressive strength at the range of 41.8 MPa and high volume of entrained air content (3.5%.

High resolution gas volume change sensor

International Nuclear Information System (INIS)

Dirckx, Joris J. J.; Aernouts, Jef E. F.; Aerts, Johan R. M.

2007-01-01

Changes of gas quantity in a system can be measured either by measuring pressure changes or by measuring volume changes. As sensitive pressure sensors are readily available, pressure change is the commonly used technique. In many physiologic systems, however, buildup of pressure influences the gas exchange mechanisms, thus changing the gas quantity change rate. If one wants to study the gas flow in or out of a biological gas pocket, measurements need to be done at constant pressure. In this article we present a highly sensitive sensor for quantitative measurements of gas volume change at constant pressure. The sensor is based on optical detection of the movement of a droplet of fluid enclosed in a capillary. The device is easy to use and delivers gas volume data at a rate of more than 15 measurements/s and a resolution better than 0.06 μl. At the onset of a gas quantity change the sensor shows a small pressure artifact of less than 15 Pa, and at constant change rates the pressure artifact is smaller than 10 Pa or 0.01% of ambient pressure

Towards high-resolution positron emission tomography for small volumes

International Nuclear Information System (INIS)

McKee, B.T.A.

1982-01-01

Some arguments are made regarding the medical usefulness of high spatial resolution in positron imaging, even if limited to small imaged volumes. Then the intrinsic limitations to spatial resolution in positron imaging are discussed. The project to build a small-volume, high resolution animal research prototype (SHARP) positron imaging system is described. The components of the system, particularly the detectors, are presented and brief mention is made of data acquisition and image reconstruction methods. Finally, some preliminary imaging results are presented; a pair of isolated point sources and 18 F in the bones of a rabbit. Although the detector system is not fully completed, these first results indicate that the goals of high sensitivity and high resolution (4 mm) have been realized. (Auth.)

Continuous AE monitoring of nuclear plants to detect flaws - status and future

International Nuclear Information System (INIS)

Hutton, P.H.

1986-01-01

This paper gives a brief commentary on the evolution of acoustic emission (AE) technology for continuous monitoring of nuclear reactors and the current status. The technical work described to support the status description has the objective of developing and validating the use of AE to detect, locate, and evaluate growing flaws in reactor pressure boundaries. The future of AE for continuous monitoring is discussed in terms of envisioned applications and further accomplishments required to achieve them. 12 refs.

Use of flawed multiple-choice items by the New England Journal of Medicine for continuing medical education.

Science.gov (United States)

Stagnaro-Green, Alex S; Downing, Steven M

2006-09-01

Physicians in the United States are required to complete a minimum number of continuing medical education (CME) credits annually. The goal of CME is to ensure that physicians maintain their knowledge and skills throughout their medical career. The New England Journal of Medicine (NEJM) provides its readers with the opportunity to obtain weekly CME credits. Deviation from established item-writing principles may result in a decrease in validity evidence for tests. This study evaluated the quality of 40 NEJM MCQs using the standard evidence-based principles of effective item writing. Each multiple-choice item reviewed had at least three item flaws, with a mean of 5.1 and a range of 3 to 7. The results of this study demonstrate that the NEJM uses flawed MCQs in its weekly CME program.

REDUCED GANGLION CELL VOLUME ON OPTICAL COHERENCE TOMOGRAPHY IN PATIENTS WITH GEOGRAPHIC ATROPHY.

Science.gov (United States)

Ramkumar, Hema L; Nguyen, Brian; Bartsch, Dirk-Uwe; Saunders, Luke J; Muftuoglu, Ilkay Kilic; You, Qisheng; Freeman, William R

2017-11-07

Geographic atrophy (GA) is the sequelae of macular degeneration. Automated inner retinal analysis using optical coherence tomography is flawed because segmentation software is calibrated for normal eyes. The purpose of this study is to determine whether ganglion cell layer (GCL) volume is reduced in GA using manual analysis. Nineteen eyes with subfoveal GA and 22 controls were selected for morphometric analyses. Heidelberg scanning laser ophthalmoscope optical coherence tomography images of the optic nerve and macula were obtained, and the Viewing Module was used to manually calibrate retinal layer segmentation. Retinal layer volumes in the central 3-mm and surrounding 6-mm diameter were measured. Linear mixed models were used for statistics. The GCL volume in the central 3 mm of the macula is less (P = 0.003), and the retinal nerve fiber layer volume is more (P = 0.02) in patients with GA when compared with controls. Ganglion cell layer volume positively correlated with outer nuclear layer volume (P = 0.020). The patients with geographic atrophy have a small significant loss of the GCL. Ganglion cell death may precede axonal loss, and increased macular retinal nerve fiber layer volumes are not indicative of GCL volume. Residual ganglion cell stimulation by interneurons may enable vision in patients with GA.

Effect of high-volume systematic local infiltration analgesia in Caesarean section

DEFF Research Database (Denmark)

Larsen, Klaus Richter; Kristensen, B B; Rasmussen, M A

2015-01-01

BACKGROUND: Pain after Caesarean section is often treated with opioids with a risk of side effects. Wound infiltration with local anaesthetics is effective and has few side effects, but volume vs. dose concentration has not been examined. METHODS: Ninety patients scheduled for elective Caesarean...... found concerning time spent in the PACU, to first mobilisation or in number of women with nausea/vomiting (P ≥ 0.05). No complications related to ropivacaine were observed. CONCLUSIONS: Systematic infiltration with a high concentration, low volume compared with low concentration, high volume showed...

High-volume infiltration analgesia in bilateral hip arthroplasty

DEFF Research Database (Denmark)

Andersen, Lasse Ø; Otte, Niels Kristian Stahl; Husted, Henrik

2011-01-01

Background and purpose High-volume infiltration analgesia may be effective in postoperative pain management after hip arthroplasty but methodological problems prevent exact interpretation of previous studies. Methods In a randomized, double-blind placebo-controlled trial in 12 patients undergoing...... bilateral total hip arthroplasty (THA) in a fast-track setting, saline or high-volume (170 mL) ropivacaine (0.2%) with epinephrine (1:100,000) was administered to the wound intraoperatively along with supplementary postoperative injections via an intraarticular epidural catheter. Oral analgesia...... was instituted preoperatively with a multimodal regimen (gabapentin, celecoxib, and acetaminophen). Pain was assessed repeatedly for 48 hours postoperatively, at rest and with 45° hip flexion. Results Pain scores were low and similar between ropivacaine and saline administration. Median hospital stay was 4...

Read-only high accuracy volume holographic optical correlator

Science.gov (United States)

Zhao, Tian; Li, Jingming; Cao, Liangcai; He, Qingsheng; Jin, Guofan

2011-10-01

A read-only volume holographic correlator (VHC) is proposed. After the recording of all of the correlation database pages by angular multiplexing, a stand-alone read-only high accuracy VHC will be separated from the VHC recording facilities which include the high-power laser and the angular multiplexing system. The stand-alone VHC has its own low power readout laser and very compact and simple structure. Since there are two lasers that are employed for recording and readout, respectively, the optical alignment tolerance of the laser illumination on the SLM is very sensitive. The twodimensional angular tolerance is analyzed based on the theoretical model of the volume holographic correlator. The experimental demonstration of the proposed read-only VHC is introduced and discussed.

High-volume infiltration analgesia in bilateral hip arthroplasty

DEFF Research Database (Denmark)

Andersen, Lasse Ø; Otte, Niels Kristian Stahl; Husted, Henrik

2011-01-01

bilateral total hip arthroplasty (THA) in a fast-track setting, saline or high-volume (170 mL) ropivacaine (0.2%) with epinephrine (1:100,000) was administered to the wound intraoperatively along with supplementary postoperative injections via an intraarticular epidural catheter. Oral analgesia...... was instituted preoperatively with a multimodal regimen (gabapentin, celecoxib, and acetaminophen). Pain was assessed repeatedly for 48 hours postoperatively, at rest and with 45° hip flexion. Results Pain scores were low and similar between ropivacaine and saline administration. Median hospital stay was 4...... (range 2-7) days. Interpretation Intraoperative high-volume infiltration with 0.2% ropivacaine with repeated intraarticular injections postoperatively may not give a clinically relevant analgesic effect in THA when combined with a multimodal oral analgesic regimen with gabapentin, celecoxib...

Automated eddy-current installation AVD-01 for detecting flaws in fuel element cans

International Nuclear Information System (INIS)

Varvaritsa, V.P.; Martishchenko, L.G.; Popov, V.K.; Romanov, M.L.; Shlepnev, I.O.; Shmatok, V.P.

1986-01-01

This paper describes an automated installation for eddy-current flaw detection in thin-walled pipes with small diameter; its unified transport system makes it possible to use the installation in inspection lines and production lines of fuel elements. The article describes the structural diagrams of the installation and presents the results of investigations connected with the selection for establishing the optimum regimes and sensitivity of feedthrough transducers with focusing screens

Policy Implications for Continuous Employment Decisions of High School Principals: An Alternative Methodological Approach for Using High-Stakes Testing Outcomes

Science.gov (United States)

Young, I. Phillip; Fawcett, Paul

2013-01-01

Several teacher models exist for using high-stakes testing outcomes to make continuous employment decisions for principals. These models are reviewed, and specific flaws are noted if these models are retrofitted for principals. To address these flaws, a different methodology is proposed on the basis of actual field data. Specially addressed are…

Improved Short-Term Outcomes following Orthognathic Surgery Are Associated with High-Volume Centers.

Science.gov (United States)

Berlin, Nicholas L; Tuggle, Charles T; Steinbacher, Derek M

2016-08-01

Previous studies assessing outcomes following orthognathic surgery rely primarily on single-center/surgeon experience. In addition to issues of generalizability, these studies are limited in evaluating the effect of operative volume on patient outcomes. Orthognathic procedures were identified in the 1999 to 2011 Healthcare Cost and Utilization Project Nationwide Inpatient Sample. Outcomes included occurrence of any in-hospital complication, extended length of stay (>2 days), and increased costs (>$10,784). High-volume hospitals were defined as the 90th percentile of case volume or higher (>31 cases/year). Univariate and multivariate analyses were conducted to identify independent predictors of outcomes. Trend analyses were performed to assess changes in the annual rate of patients treated at high-volume hospitals over the study period. Among 101,692 orthognathic surgery patients, 19.6 percent underwent concurrent ancillary procedures (i.e., genioplasty, rhinoplasty, or septoplasty), and 37.6 percent underwent double-jaw surgery. Fifty-three percent were treated at high-volume hospitals. High-volume hospitals more often performed ancillary procedures (21.4 percent versus 17.4 percent; p surgery (41.3 percent versus 33.4 percent; p orthognathic cases nationwide are performed at a small number of high-volume hospitals. These hospitals discharge patients earlier, perform more complex procedures, and have fewer complications. Risk, III.

Low-volume high-intensity swim training is superior to high-volume low-intensity training in relation to insulin sensitivity and glucose control in inactive middle-aged women.

Science.gov (United States)

Connolly, Luke J; Nordsborg, Nikolai B; Nyberg, Michael; Weihe, Pál; Krustrup, Peter; Mohr, Magni

2016-10-01

We tested the hypothesis that low-volume high-intensity swimming has a larger impact on insulin sensitivity and glucose control than high-volume low-intensity swimming in inactive premenopausal women with mild hypertension. Sixty-two untrained premenopausal women were randomised to an inactive control (n = 20; CON), a high-intensity low-volume (n = 21; HIT) or a low-intensity high-volume (n = 21; LIT) training group. During the 15-week intervention period, HIT performed 3 weekly 6-10 × 30-s all-out swimming intervals (average heart rate (HR) = 86 ± 3 % HRmax) interspersed by 2-min recovery periods and LIT swam continuously for 1 h at low intensity (average HR = 73 ± 3 % HRmax). Fasting blood samples were taken and an oral glucose tolerance test (OGTT) was conducted pre- and post-intervention. After HIT, resting plasma [insulin] was lowered (17 ± 34 %; P high-intensity intermittent swimming is an effective and time-efficient training strategy for improving insulin sensitivity, glucose control and biomarkers of vascular function in inactive, middle-aged mildly hypertensive women.

High volume tidal or current flow harnessing system

Energy Technology Data Exchange (ETDEWEB)

Gorlov, A.M.

1984-08-07

Apparatus permitting the utilization of large volumes of water in the harnessing and extracting of a portion of the power generated by the rise and fall of ocean tides, ocean currents, or flowing rivers includes the provision of a dam, and a specialized single cavity chamber of limited size as compared with the water head enclosed by the dam, and an extremely high volume gating system in which all or nearly all of the water between the high and low levels on either side of the dam is cyclically gated through the single chamber from one side of the dam to the other so as to alternately provide positive air pressure and a partial vacuum within the single chamber. In one embodiment, the specialized chamber has a barrier at the bottom which divides the bottom of the chamber in half, large ports at the bottom of the chamber to permit inflow and outflow of high volumes of water, and ganged structures having a higher total area than that of corresponding ports, in which the structures form sluice gates to selectively seal off and open different sets of ports. In another embodiment, a single chamber is used without a barrier. In this embodiment, vertical sluice gates are used which may be activated automatically by pressures acting on the sluice gates as a result of ingested and expelled water.

High-level waste borosilicate glass: A compendium of corrosion characteristics. Volume 2

International Nuclear Information System (INIS)

Cunnane, J.C.

1994-03-01

The objective of this document is to summarize scientific information pertinent to evaluating the extent to which high-level waste borosilicate glass corrosion and the associated radionuclide release processes are understood for the range of environmental conditions to which waste glass may be exposed in service. Alteration processes occurring within the bulk of the glass (e.g., devitrification and radiation-induced changes) are discussed insofar as they affect glass corrosion.This document is organized into three volumes. Volumes I and II represent a tiered set of information intended for somewhat different audiences. Volume I is intended to provide an overview of waste glass corrosion, and Volume 11 is intended to provide additional experimental details on experimental factors that influence waste glass corrosion. Volume III contains a bibliography of glass corrosion studies, including studies that are not cited in Volumes I and II. Volume I is intended for managers, decision makers, and modelers, the combined set of Volumes I, II, and III is intended for scientists and engineers working in the field of high-level waste

High-level waste borosilicate glass: A compendium of corrosion characteristics. Volume 2

Energy Technology Data Exchange (ETDEWEB)

Cunnane, J.C. [comp.; Bates, J.K.; Bradley, C.R. [Argonne National Lab., IL (United States)] [and others

1994-03-01

The objective of this document is to summarize scientific information pertinent to evaluating the extent to which high-level waste borosilicate glass corrosion and the associated radionuclide release processes are understood for the range of environmental conditions to which waste glass may be exposed in service. Alteration processes occurring within the bulk of the glass (e.g., devitrification and radiation-induced changes) are discussed insofar as they affect glass corrosion.This document is organized into three volumes. Volumes I and II represent a tiered set of information intended for somewhat different audiences. Volume I is intended to provide an overview of waste glass corrosion, and Volume 11 is intended to provide additional experimental details on experimental factors that influence waste glass corrosion. Volume III contains a bibliography of glass corrosion studies, including studies that are not cited in Volumes I and II. Volume I is intended for managers, decision makers, and modelers, the combined set of Volumes I, II, and III is intended for scientists and engineers working in the field of high-level waste.

Validation of favor code linear elastic fracture solutions for finite-length flaw geometries

International Nuclear Information System (INIS)

Dickson, T.L.; Keeney, J.A.; Bryson, J.W.

1995-01-01

One of the current tasks within the US Nuclear Regulatory Commission (NRC)-funded Heavy Section Steel Technology Program (HSST) at Oak Ridge National Laboratory (ORNL) is the continuing development of the FAVOR (Fracture, analysis of Vessels: Oak Ridge) computer code. FAVOR performs structural integrity analyses of embrittled nuclear reactor pressure vessels (RPVs) with stainless steel cladding, to evaluate compliance with the applicable regulatory criteria. Since the initial release of FAVOR, the HSST program has continued to enhance the capabilities of the FAVOR code. ABAQUS, a nuclear quality assurance certified (NQA-1) general multidimensional finite element code with fracture mechanics capabilities, was used to generate a database of stress-intensity-factor influence coefficients (SIFICs) for a range of axially and circumferentially oriented semielliptical inner-surface flaw geometries applicable to RPVs with an internal radius (Ri) to wall thickness (w) ratio of 10. This database of SIRCs has been incorporated into a development version of FAVOR, providing it with the capability to perform deterministic and probabilistic fracture analyses of RPVs subjected to transients, such as pressurized thermal shock (PTS), for various flaw geometries. This paper discusses the SIFIC database, comparisons with other investigators, and some of the benchmark verification problem specifications and solutions

Combining usability evaluations to highlight the chain that leads from usability flaws to usage problems and then negative outcomes.

Science.gov (United States)

Watbled, Ludivine; Marcilly, Romaric; Guerlinger, Sandra; Bastien, J-M Christian; Beuscart-Zéphir, Marie-Catherine; Beuscart, Régis

2018-02-01

Poor usability of health technology is thought to diminish work system performance, increase error rates and, potentially, harm patients. The present study (i) used a combination of usability evaluation methods to highlight the chain that leads from usability flaws to usage problems experienced by users and, ultimately, to negative patient outcomes, and (ii) validated this approach by studying two different discharge summary production systems. To comply with quality guidelines, the process of drafting and sending discharge summaries is increasingly being automated. However, the usability of these systems may modify their impact (or the absence thereof) in terms of production times and quality, and must therefore be evaluated. Here, we applied three successive techniques for usability evaluation (heuristic evaluation, user testing and field observation) to two discharge summary production systems (underpinned by different technologies). The systems' main usability flaws led respectively to an increase in the time need to produce a discharge summary and the risk of patient misidentification. Our results are discussed with regard to the possibility of linking the usability flaws, usage problems and the negative outcomes by successively applying three methods for evaluating usability (heuristic evaluation, user testing and in situ observations) throughout the system development life cycle. Copyright © 2018 Elsevier Inc. All rights reserved.

Final Assessment of Manual Ultrasonic Examinations Applied to Detect Flaws in Primary System Dissimilar Metal Welds at North Anna Power Station

Energy Technology Data Exchange (ETDEWEB)

Anderson, Michael T.; Diaz, Aaron A.; Cinson, Anthony D.; Crawford, Susan L.; Prowant, Matthew S.; Doctor, Steven R.

2014-03-24

PNNL conducted a technical assessment of the NDE issues and protocols that led to missed detections of several axially oriented flaws in a steam generator primary inlet dissimilar metal weld at North Anna Power Station, Unit 1 (NAPS-1). This particular component design exhibits a significant outside-diameter (OD) taper that is not included as a blind performance demonstration mock-up within the industry’s Performance Demonstration Initiative, administered by EPRI. For this reason, the licensee engaged EPRI to assist in the development of a technical justification to support the basis for a site-specific qualification. The service-induced flaws at NAPS-1 were eventually detected as a result of OD surface machining in preparation for a full structural weld overlay. The machining operation uncovered the existence of two through-wall flaws, based on the observance of primary water leaking from the dissimilar metal weld. A total of five axially oriented flaws were detected in varied locations around the weld circumference. The field volumetric examination that was conducted at NAPS-1 was a non-encoded, real-time manual ultrasonic examination. PNNL conducted both an initial assessment, and subsequently, a more rigorous technical evaluation (reported here), which has identified an array of NDE issues that may have led to the subject missed detections. These evaluations were performed through technical reviews and discussions with NRC staff, EPRI NDE Center personnel, industry and ISI vendor personnel, and ultrasonic transducer manufacturers, and laboratory tests, to better understand the underlying issues at North Anna.

Flaws in the Concept of Nuclear Deterrance

Directory of Open Access Journals (Sweden)

John Scales Avery

2012-04-01

Full Text Available The concept of nuclear deterrence is seriously flawed, and it violates the fundamental ethical principles of all major religions. Besides being morally unacceptable, nuclear weapons are also illegal according to a historic 1996 decision of the International Court of Justice, a ruling that reflects the opinion of the vast majority of the worldʼs peoples. Even a small nuclear war would be an ecological catastrophe, not only killing civilian populations indiscriminately in both belligerent and neutral countries, but also severely damaging global agriculture and making large areas of the earth permanently uninhabitable through radioactive contamination. The danger of accidental nuclear war continues to be very great today, and the danger of nuclear terrorism is increasing. In this perilous situation, it is necessary for the nuclear nations to acknowledge that the concept of deterrence has been a mistake, which is threatening the lives of all human beings as well as threatening devastation of the biosphere. Acknowledging that the policy of nuclear deterrence has been a grave error can reduce risk of nuclear weapons proliferation.

The deflation limb of the pressure-volume relationship in infants during high-frequency ventilation.

Science.gov (United States)

Tingay, David G; Mills, John F; Morley, Colin J; Pellicano, Anastasia; Dargaville, Peter A

2006-02-15

The importance of applying high-frequency oscillatory ventilation with a high lung volume strategy in infants is well established. Currently, a lack of reliable methods for assessing lung volume limits clinicians' ability to achieve the optimum volume range. To map the pressure-volume relationship of the lung during high-frequency oscillatory ventilation in infants, to determine at what point ventilation is being applied clinically, and to describe the relationship between airway pressure, lung volume, and oxygenation. In 12 infants, a partial inflation limb and the deflation limb of the pressure-volume relationship were mapped using a quasi-static lung volume optimization maneuver. This involved stepwise airway pressure increments to total lung capacity, followed by decrements until the closing pressure of the lung was identified. Lung volume and oxygen saturation were recorded at each airway pressure. Lung volume was measured using respiratory inductive plethysmography. A distinct deflation limb could be mapped in each infant. Overall, oxygenation and lung volume were improved by applying ventilation on the deflation limb. Maximal lung volume and oxygenation occurred on the deflation limb at a mean airway pressure of 3 and 5 cm H(2)O below the airway pressure approximating total lung capacity, respectively. Using current ventilation strategies, all infants were being ventilated near the inflation limb. It is possible to delineate the deflation limb in infants receiving high-frequency oscillatory ventilation; in doing so, greater lung volume and oxygenation can be achieved, often at lower airway pressures.

Aplikace pro penetrační testování webových zranitelností typu Data Validation flaws

OpenAIRE

Němec, Václav

2011-01-01

Tato bakalářské práce se zabývá detekcí webových zranitelností typu Data validation flaws. V práci jsou popsány běžné útoky, obrana před těmito útoky a postupy při automatické detekci. Hlavním cílem je návrh a implementace nástroje pro automatickou detekci zranitelností typu Data validation flaws, jeho otestování a srovnání výsledků s podobnými nástroji jako například Paros Proxy nebo Burp Suite. This bachelor's thesis deals with detection of web vulnerabilities such as data validation fla...

High-volume recycled materials for sustainable pavement construction.

Science.gov (United States)

2017-05-01

The main objective of this research is to evaluate the feasibility of using high-volume recycled materials for concrete production in rigid pavement. The goal was to replace 50% of the solids with recycled materials and industrial by-products. The pe...

Volumizing effects of a smooth, highly cohesive, viscous 20-mg/mL hyaluronic acid volumizing filler: prospective European study

Directory of Open Access Journals (Sweden)

Hoffmann Klaus

2009-08-01

Full Text Available Abstract Background Facial volume loss contributes significantly to facial aging. The 20-mg/mL hyaluronic acid (HA formulation used in this study is a smooth, highly cohesive, viscous, fully reversible, volumizing filler indicated to restore facial volume. This first prospective study evaluated use in current aesthetic clinical practice. Methods A pan-European evaluation conducted under guidelines of the World Association of Opinion and Marketing Research, the trial comprised a baseline visit (visit 1 and a follow-up (visit 2 at 14 ± 7 days posttreatment. Physicians photographed patients at each visit. Each patient was treated with the 20-mg/mL HA volumizing filler as supplied in standard packaging. Procedural details, aesthetic outcomes, safety, and physician and patient ratings of their experience were recorded. Results Fifteen physicians and 70 patients (91% female; mean age: 50 years participated. Mean volume loss at baseline was 3.7 (moderate on the Facial Volume Loss Scale. Local anesthesia was used in 64.3% of cases. Most injections (85% were administered with needles rather than cannulas. Of the 208 injections, 59% were in the malar region, primarily above the periosteum. Subcutaneous injections were most common for other sites. The mean total injection volume per patient was 4.6 mL. The mean volume loss score declined significantly (P Conclusion The 20-mg/mL smooth, highly cohesive, viscous, volumizing HA filler was effective, well tolerated, and easy to use in current clinical practice. Participants were very likely to recommend this product to colleagues and friends, and patients would be very or quite likely to request this product for future treatments.

Powder metallurgical high performance materials. Proceedings. Volume 4: late papers

Energy Technology Data Exchange (ETDEWEB)

Kneringer, G; Roedhammer, P; Wildner, H [eds.

2001-07-01

This is the fourth volume (late papers) of the 15th International Plansee seminar 2001 which general theme was 'Powder metallurgical high performance materials'. The seminar looked beyond the refractory metals and cemented carbides, which remain as its focus, to novel classes of materials, such as intermetallic compounds, with potential for high temperature applications. This volume 4 contains papers dealing with high performance P/M metals (ITER and fusion reactors, solid targets, materials microstructure, novel alloys, etc.), P/M hard materials ( production and characterization, tungsten carbides, titanium carbides, microstructural design, coatings composition and performance, etc.) and general topics. From 37 papers 24 correspond to INIS subject scope and they were indexed separately. (nevyjel)

Powder metallurgical high performance materials. Proceedings. Volume 4: late papers

International Nuclear Information System (INIS)

Kneringer, G.; Roedhammer, P.; Wildner, H.

2001-01-01

This is the fourth volume (late papers) of the 15th International Plansee seminar 2001 which general theme was 'Powder metallurgical high performance materials'. The seminar looked beyond the refractory metals and cemented carbides, which remain as its focus, to novel classes of materials, such as intermetallic compounds, with potential for high temperature applications. This volume 4 contains papers dealing with high performance P/M metals (ITER and fusion reactors, solid targets, materials microstructure, novel alloys, etc.), P/M hard materials ( production and characterization, tungsten carbides, titanium carbides, microstructural design, coatings composition and performance, etc.) and general topics. From 37 papers 24 correspond to INIS subject scope and they were indexed separately. (nevyjel)

'Moral distress'--time to abandon a flawed nursing construct?

Science.gov (United States)

Johnstone, Megan-Jane; Hutchinson, Alison

2015-02-01

Moral distress has been characterised in the nursing literature as a major problem affecting nurses in all healthcare systems. It has been portrayed as threatening the integrity of nurses and ultimately the quality of patient care. However, nursing discourse on moral distress is not without controversy. The notion itself is conceptually flawed and suffers from both theoretical and practical difficulties. Nursing research investigating moral distress is also problematic on account of being methodologically weak and disparate. Moreover, the ultimate purpose and significance of the research is unclear. In light of these considerations, it is contended that the notion of moral distress ought to be abandoned and that concerted attention be given to advancing inquiries that are more conducive to improving the quality and safety of moral decision-making, moral conduct and moral outcomes in nursing and healthcare domains. © The Author(s) 2013.

Perspectives on High School Reform. NCREL Viewpoints, Volume 13

Science.gov (United States)

Learning Point Associates / North Central Regional Educational Laboratory (NCREL), 2005

2005-01-01

Viewpoints is a multimedia package containing two audio CDs and a brief, informative booklet. This volume of Viewpoints focuses on issues related to high school reform. This booklet offers background information explaining the issues surrounding high school reform with perspectives from research, policy, and practice. It also provides a list of…

High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems

Energy Technology Data Exchange (ETDEWEB)

Turnquist, Norman [GE Global Research, Munchen (Germany); Qi, Xuele [GE Global Research, Munchen (Germany); Raminosoa, Tsarafidy [GE Global Research, Munchen (Germany); Salas, Ken [GE Global Research, Munchen (Germany); Samudrala, Omprakash [GE Global Research, Munchen (Germany); Shah, Manoj [GE Global Research, Munchen (Germany); Van Dam, Jeremy [GE Global Research, Munchen (Germany); Yin, Weijun [GE Global Research, Munchen (Germany); Zia, Jalal [GE Global Research, Munchen (Germany)

2013-12-20

This report summarizes the progress made during the April 01, 2010 – December 30, 2013 period under Cooperative Agreement DE-EE0002752 for the U.S. Department of Energy entitled “High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems.” The overall objective of this program is to advance the technology for well fluids lifting systems to meet the foreseeable pressure, temperature, and longevity needs of the Enhanced Geothermal Systems (EGS) industry for the coming ten years. In this program, lifting system requirements for EGS wells were established via consultation with industry experts and site visits. A number of artificial lift technologies were evaluated with regard to their applicability to EGS applications; it was determined that a system based on electric submersible pump (ESP) technology was best suited to EGS. Technical barriers were identified and a component-level technology development program was undertaken to address each barrier, with the most challenging being the development of a power-dense, small diameter motor that can operate reliably in a 300°C environment for up to three years. Some of the targeted individual component technologies include permanent magnet motor construction, high-temperature insulation, dielectrics, bearings, seals, thrust washers, and pump impellers/diffusers. Advances were also made in thermal management of electric motors. In addition to the overall system design for a full-scale EGS application, a subscale prototype was designed and fabricated. Like the full-scale design, the subscale prototype features a novel “flow-through-the-bore” permanent magnet electric motor that combines the use of high temperature materials with an internal cooling scheme that limits peak internal temperatures to <330°C. While the full-scale high-volume multi-stage pump is designed to lift up to 80 kg/s of process water, the subscale prototype is based on a production design that can pump 20 kg/s and has been modified

Going the Extra Mile: Improved Survival for Pancreatic Cancer Patients Traveling to High-volume Centers.

Science.gov (United States)

Lidsky, Michael E; Sun, Zhifei; Nussbaum, Daniel P; Adam, Mohamed A; Speicher, Paul J; Blazer, Dan G

2017-08-01

This study compares outcomes following pancreaticoduodenectomy (PD) for patients treated at local, low-volume centers and those traveling to high-volume centers. Although outcomes for PD are superior at high-volume institutions, not all patients live in proximity to major medical centers. Theoretical advantages for undergoing surgery locally exist. The 1998 to 2012 National Cancer Data Base was queried for T1-3N0-1M0 pancreatic adenocarcinoma patients who underwent PD. Travel distances to treatment centers were calculated. Overlaying the upper and lower quartiles of travel distance with institutional volume established short travel/low-volume (ST/LV) and long travel/high-volume (LT/HV) cohorts. Overall survival was evaluated. Of 7086 patients, 773 ST/LV patients traveled ≤6.3 (median 3.2) miles to centers performing ≤3.3 PDs yearly, and 758 LT/HV patients traveled ≥45 (median 97.3) miles to centers performing ≥16 PDs yearly. LT/HV patients had higher stage disease (P travel to a high-volume center remained associated with reduced long-term mortality (hazard ratio 0.75, P travel burden, patients treated at high-volume centers had improved perioperative outcomes, short-term mortality, and overall survival. These data support ongoing efforts to centralize care for patients undergoing PD.

Moderator's view: High-volume plasma exchange: pro, con and consensus.

Science.gov (United States)

Kaplan, Andre A

2017-09-01

I have been asked to comment on the pro and con opinions regarding high-volume plasma exchange. The authors of both positions have provided cogent arguments and a reasonable approach to choosing the exchange volume for any given therapeutic plasma exchange. The major issue of relevance in this discussion is the nature of the toxins targeted for removal. These parameters include molecular weight, the apparent volume of distribution, the degree of protein binding, the biologic and chemical half-life, and the severity and rapidity of its toxicity. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Case study of the propagation of a small flaw under PWR loading conditions and comparison with the ASME code design life. Comparison of ASME Code Sections III and XI

International Nuclear Information System (INIS)

Yahr, G.T.; Gwaltney, R.C.; Richardson, A.K.; Server, W.L.

1986-01-01

A cooperative study was performed by EG and G Idaho, Inc., and Oak Ridge National Laboratory to investigate the degree of conservatism and consistency in the ASME Boiler and Pressure Vessel Code Section III fatigue evaluation procedure and Section XI flaw acceptance standards. A single, realistic, sample problem was analyzed to determine the significance of certain points of criticism made of an earlier parametric study by staff members of the Division of Engineering Standards of the Nuclear Regulatory Commission. The problem was based on a semielliptical flaw located on the inside surface of the hot-leg piping at the reactor vessel safe-end weld for the Zion 1 pressurized-water reactor (PWR). Two main criteria were used in selecting the problem; first, it should be a straight pipe to minimize the computational expense; second, it should exhibit as high a cumulative usage factor as possible. Although the problem selected has one of the highest cumulative usage factors of any straight pipe in the primary system of PWRs, it is still very low. The Code Section III fatigue usage factor was only 0.00046, assuming it was in the as-welded condition, and fatigue crack-growth analyses predicted negligible crack growth during the 40-year design life. When the analyses were extended past the design life, the usage factor was less than 1.0 when the flaw had propagated to failure. The current study shows that the criticism of the earlier report should not detract from the conclusion that if a component experiences a high level of cyclic stress corresponding to a fatigue usage factor near 1.0, very small cracks can propagate to unacceptable sizes

Research program plan. Non-destructive examination. Volume 4

International Nuclear Information System (INIS)

Muscara, J.

1985-07-01

Nondestructive examination/evaluation (NDE) of nuclear reactor components is required during fabrication, before service, and at regularly scheduled shutdowns for periodic inservice inspection (ISI). Any flaws produced during fabrication should be detected by the fabrication and preservice baseline examinations and components containing rejectable flaws should be repaired before the reactor enters service. The purpose of ISI is to ensure that any flaws which develop during service can be detected and evaluated and that unacceptable components are repaired or replaced to maintain safety, as well as to identify possible generic-type defects that may be present or developing in the remainder of the system or other similar systems so that timely corrective actions can be taken. The major thrusts of the research in ultrasonic testing for ISI are (1) to define the influence of inspection variables and procedures on inspection reliability and to determine the impact of inspection unreliability on system safety and (2) to study and evaluate improved techniques for reliable and accurate flaw detection and characterization. This research, therefore, has direct impact on evaluations of and improvements in reactor safety

Case mix-adjusted cost of colectomy at low-, middle-, and high-volume academic centers.

Science.gov (United States)

Chang, Alex L; Kim, Young; Ertel, Audrey E; Hoehn, Richard S; Wima, Koffi; Abbott, Daniel E; Shah, Shimul A

2017-05-01

Efforts to regionalize surgery based on thresholds in procedure volume may have consequences on the cost of health care delivery. This study aims to delineate the relationship between hospital volume, case mix, and variability in the cost of operative intervention using colectomy as the model. All patients undergoing colectomy (n = 90,583) at 183 academic hospitals from 2009-2012 in The University HealthSystems Consortium Database were studied. Patient and procedure details were used to generate a case mix-adjusted predictive model of total direct costs. Observed to expected costs for each center were evaluated between centers based on overall procedure volume. Patient and procedure characteristics were significantly different between volume tertiles. Observed costs at high-volume centers were less than at middle- and low-volume centers. According to our predictive model, high-volume centers cared for a less expensive case mix than middle- and low-volume centers ($12,786 vs $13,236 and $14,497, P case mix at low-volume centers, which may lead to perceived poor performance at these centers. Copyright © 2016 Elsevier Inc. All rights reserved.

Engineering approach for examining crack growth and stability in flawed structures

International Nuclear Information System (INIS)

Shih, C.F.

1980-01-01

Progress made in two research programs sponsored by the Electric Power Research Institute (EPRI), to identify viable parameters for characterizing crack initiation and continued extension, and to develop an engineering/design methodology, based on these parameters, for the assessment of crack growth and instability in engineering structures which are stressed beyond the regime of applicability of linear elastic fracture mechanics is reported. The goal in the development of such methodology is to establish an improved basis for analyzing the effect of flaws (postulated or detected) on the safety margins of pressure boundary components of light water-cooled type nuclear steam supply systems. The methodology can also be employed for structural integrity analyses of other engineering structures

Developmental techniques for ultrasonic flaw detection and characterization in stainless steel

International Nuclear Information System (INIS)

Kupperman, D.S.

1983-04-01

Flaw detection and characterization by ultrasonic methods is particularly difficult for stainless steel. This paper focuses on two specific problem areas: (a) the inspection of centrifugally cast stainless steel (CCSS) and (b) the differentiation of intergranular stress-corrosion cracking (IGSCC) from geometrical reflectors such as the weld root. To help identify optimal conditions for the ultrasonic inspection of CCSS, the effect of frequency on propagation of longitudinal and shear waves was examined in both isotropic and anisotropic samples. Good results were obtained with isotropic CCSS and 0.5-MHz angle beam shear waves. The use of beam-scattering patterns (i.e. signal amplitude vs skew angle) as a tool for discriminating IGSCC from geometrical reflectors is also discussed

The effect of chronic erythrocytic polycythemia and high altitude upon plasma and blood volumes.

Science.gov (United States)

Burton, R. R.; Smith, A. H.

1972-01-01

Comparison of two kinds of physiological chronic erythrocytic polycythemias in order to differentiate the specific effect of erythrocytic polycythemia from the general effects of high altitude upon the plasma volume. The two kinds were produced hormonally in female chickens, at sea level, or by protracted high-altitude exposures. It appears that the vascular system of the body may account for an increase in red blood cell mass either by reduction in plasma volume, or by no change in plasma volume, resulting in differential changes in total blood volumes.

Highly Insulating Windows Volume Purchase Program Final Report

Energy Technology Data Exchange (ETDEWEB)

None

2013-04-01

This report documents the development, execution outcomes and lessons learned of the Highly Insulating Windows Volume Purchase (WVP) Program carried out over a three-year period from 2009 through 2012. The primary goals of the program were met: 1) reduce the incremental cost of highly insulating windows compared to ENERGY STAR windows; and 2) raise the public and potential buyers’ awareness of highly insulating windows and their benefits. A key outcome of the program is that the 2013 ENERGY STAR Most Efficient criteria for primary residential windows were adopted from the technical specifications set forth in the WVP program.

Verification and validation guidelines for high integrity systems. Volume 1

Energy Technology Data Exchange (ETDEWEB)

Hecht, H.; Hecht, M.; Dinsmore, G.; Hecht, S.; Tang, D. [SoHaR, Inc., Beverly Hills, CA (United States)

1995-03-01

High integrity systems include all protective (safety and mitigation) systems for nuclear power plants, and also systems for which comparable reliability requirements exist in other fields, such as in the process industries, in air traffic control, and in patient monitoring and other medical systems. Verification aims at determining that each stage in the software development completely and correctly implements requirements that were established in a preceding phase, while validation determines that the overall performance of a computer system completely and correctly meets system requirements. Volume I of the report reviews existing classifications for high integrity systems and for the types of errors that may be encountered, and makes recommendations for verification and validation procedures, based on assumptions about the environment in which these procedures will be conducted. The final chapter of Volume I deals with a framework for standards in this field. Volume II contains appendices dealing with specific methodologies for system classification, for dependability evaluation, and for two software tools that can automate otherwise very labor intensive verification and validation activities.

Verification and validation guidelines for high integrity systems. Volume 1

International Nuclear Information System (INIS)

Hecht, H.; Hecht, M.; Dinsmore, G.; Hecht, S.; Tang, D.

1995-03-01

High integrity systems include all protective (safety and mitigation) systems for nuclear power plants, and also systems for which comparable reliability requirements exist in other fields, such as in the process industries, in air traffic control, and in patient monitoring and other medical systems. Verification aims at determining that each stage in the software development completely and correctly implements requirements that were established in a preceding phase, while validation determines that the overall performance of a computer system completely and correctly meets system requirements. Volume I of the report reviews existing classifications for high integrity systems and for the types of errors that may be encountered, and makes recommendations for verification and validation procedures, based on assumptions about the environment in which these procedures will be conducted. The final chapter of Volume I deals with a framework for standards in this field. Volume II contains appendices dealing with specific methodologies for system classification, for dependability evaluation, and for two software tools that can automate otherwise very labor intensive verification and validation activities

Self compacting concrete incorporating high-volumes of fly ash

Energy Technology Data Exchange (ETDEWEB)

Bouzoubaa, N. [Natural Resources Canada, Ottawa, ON (Canada). International Centre for Sustainable Development of Cement and Concrete; Lachemi, M. [Ryerson Polytechnic Univ., Toronto, ON (Canada). Dept. of Civil Engineering

2004-07-01

Self-compacting concrete (SCC) is now widely used in reinforced concrete structures. Fine materials such as fly ash ensure that the concrete has the necessary properties of high fluidity and cohesiveness. An experimental study was conducted in which 9 SCC mixtures and one control concrete were produced in order to evaluate SCC made with high-volumes of fly ash. The content of the cementitious materials remained constant at 400 kg/cubic metre, but the ratio of water to cementitious material ranged from 0.35 to 0.45. The viscosity and stability of the fresh concrete was determined for self-compacting mixtures of 40, 50 and 60 per cent Class F fly ash. The compressive strength and drying shrinkage were also determined for the hardened concretes. Results showed that the SCCs developed a 28-day compressive strength ranging from 26 to 48 MPa. It was concluded that high-volumes of Class F fly ash could offer the following advantages to an SCC: reduced construction time and labour cost; eliminate the need for vibration; reduce noise pollution; improve the filling capacity of highly congested structural members; and, ensure good structural performance. 19 refs., 8 tabs., 2 figs.

Is the Distance Worth It? Patients With Rectal Cancer Traveling to High-Volume Centers Experience Improved Outcomes.

Science.gov (United States)

Xu, Zhaomin; Becerra, Adan Z; Justiniano, Carla F; Boodry, Courtney I; Aquina, Christopher T; Swanger, Alex A; Temple, Larissa K; Fleming, Fergal J

2017-12-01

It is unclear whether traveling long distances to high-volume centers would compensate for travel burden among patients undergoing rectal cancer resection. The purpose of this study was to determine whether operative volume outweighs the advantages of being treated locally by comparing the outcomes of patients with rectal cancer treated at local, low-volume centers versus far, high-volume centers. This was a population-based study. The National Cancer Database was queried for patients with rectal cancer. Patients with stage II or III rectal cancer who underwent surgical resection between 2006 and 2012 were included. The outcomes of interest were margins, lymph node yield, receipt of neoadjuvant chemoradiation, adjuvant chemotherapy, readmission within 30 days, 30-day and 90-day mortality, and 5-year overall survival. A total of 18,605 patients met inclusion criteria; 2067 patients were in the long-distance/high-volume group and 1362 in the short-distance/low-volume group. The median travel distance was 62.6 miles for the long-distance/high-volume group and 2.3 miles for the short-distance/low-volume group. Patients who were younger, white, privately insured, and stage III were more likely to have traveled to a high-volume center. When controlled for patient factors, stage, and hospital factors, patients in the short-distance/low-volume group had lower odds of a lymph node yield ≥12 (OR = 0.51) and neoadjuvant chemoradiation (OR = 0.67) and higher 30-day (OR = 3.38) and 90-day mortality (OR = 2.07) compared with those in the long-distance/high-volume group. The short-distance/low-volume group had a 34% high risk of overall mortality at 5 years compared with the long-distance/high-volume group. We lacked data regarding patient and physician decision making and surgeon-specific factors. Our results indicate that when controlled for patient, tumor, and hospital factors, patients who traveled a long distance to a high-volume center had improved lymph node yield

Focussed probes ultrasonic follow-up of actual flaw growth during fatigue testing

International Nuclear Information System (INIS)

Cinotti, C.; Dufresne, J.; Prot, A.C.; Touffait, A.M.; Saglio, R.

1979-01-01

A programme was undertaken to follow-up the growth of actual flaws purposely introduced during the welding process of five test specimens. The aim of this programme is to measure the actual size of the cracks which develop from the known defects during the fatigue testing. The sizing method is based on the use of focussed probes, which allow good accuracy and repeatability, as well as good sensitivity. Examples are given of the first results: sizing before testing, then step by step during the fatigue testing and also under compression. This last point is very important in view of the ultrasonic testing during periodic in-service inspection

High-pressure-assisted synthesis of high-volume ZnGeP2 polycrystalline

Science.gov (United States)

Huang, Changbao; Wu, Haixin; Xiao, Ruichun; Chen, Shijing; Ma, Jiaren

2018-06-01

The pnictide and chalcogenide semiconductors are promising materials for the applications in the field of photoelectric. High-purity and high-volume polycrystalline required in the real-world applications is hard to be synthesized due to the high vapor pressure of phosphorus and sulfur components at high temperature. A new high-pressure-resisted method was used to investigate the synthesis of the nonlinear-optical semiconductor ZnGeP2. The high-purity ZnGeP2 polycrystalline material of approximately 500 g was synthesized in one run, which enables the preparation of nominally stoichiometric material. Since increasing internal pressure resistance of quartz crucible and reducing the reaction space, the high-pressure-resisted method can be used to rapidly synthesize other pnictide and chalcogenide semiconductors and control the components ratio.

Design Flaws and Service System Breakdowns: Learning from Systems Thinking

Directory of Open Access Journals (Sweden)

David Ing

2014-12-01

Full Text Available In what ways might systems thinking be helpful to designers?  In the 21st century, the types of project with which designers have become engaged has expanded to include service systems.  Service systems are typically composites of mechanisms, organisms, human beings and ecologies.  Systems thinking is a perspective with theories, methods and practices that enables transcending disciplinary boundaries.  Application of systems thinking in designing a service system can aid in surfacing potential flaws and/or anticipating future breakdowns in functions, structures and/or processes. Designers and systems thinkers should work together to improve the nature of service systems.  As a starter set into these conversations, seven conditions are proposed as a starting context.  These conditions are presented neither as rigourously defined nor as exhaustive, but as an entry point into future joint engagement.

High tidal volume decreases adult respiratory distress syndrome, atelectasis, and ventilator days compared with low tidal volume in pediatric burned patients with inhalation injury.

Science.gov (United States)

Sousse, Linda E; Herndon, David N; Andersen, Clark R; Ali, Arham; Benjamin, Nicole C; Granchi, Thomas; Suman, Oscar E; Mlcak, Ronald P

2015-04-01

Inhalation injury, which is among the causes of acute lung injury and acute respiratory distress syndrome (ARDS), continues to represent a significant source of mortality in burned patients. Inhalation injury often requires mechanical ventilation, but the ideal tidal volume strategy is not clearly defined in burned pediatric patients. The aim of this study was to determine the effects of low and high tidal volume on the number of ventilator days, ventilation pressures, and incidence of atelectasis, pneumonia, and ARDS in pediatric burned patients with inhalation injury within 1 year post burn injury. From 1986 to 2014, inhalation injury was diagnosed by bronchoscopy in pediatric burned patients (n = 932). Patients were divided into 3 groups: unventilated (n = 241), high tidal volume (HTV, 15 ± 3 mL/kg, n = 190), and low tidal volume (LTV, 9 ± 3 mL/kg, n = 501). High tidal volume was associated with significantly decreased ventilator days (p tidal volume significantly decreases ventilator days and the incidence of both atelectasis and ARDS compared with low tidal volume in pediatric burned patients with inhalation injury. Therefore, the use of HTV may interrupt sequences leading to lung injury in our patient population. Copyright © 2015 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Durability properties of high volume fly ash self compacting concretes

Energy Technology Data Exchange (ETDEWEB)

P. Dinakar; K.G. Babu; Manu Santhanam [Indian Institute of Technology, Chennai (India). Building Technology Division

2008-11-15

This paper presents an experimental study on the durability properties of self compacting concretes (SCCs) with high volume replacements of fly ash. Eight fly ash self compacting concretes of various strength grades were designed at desired fly ash percentages of 0, 10, 30, 50, 70 and 85%, in comparison with five different mixtures of normal vibrated concretes (NCs) at equivalent strength grades. The durability properties were studied through the measurement of permeable voids, water absorption, acid attack and chloride permeation. The results indicated that the SCCs showed higher permeable voids and water absorption than the vibrated normal concretes of the same strength grades. However, in acid attack and chloride diffusion studies the high volume fly ash SCCs had significantly lower weight losses and chloride ion diffusion.

Volume measurement variability in three-dimensional high-frequency ultrasound images of murine liver metastases

International Nuclear Information System (INIS)

Wirtzfeld, L A; Graham, K C; Groom, A C; MacDonald, I C; Chambers, A F; Fenster, A; Lacefield, J C

2006-01-01

The identification and quantification of tumour volume measurement variability is imperative for proper study design of longitudinal non-invasive imaging of pre-clinical mouse models of cancer. Measurement variability will dictate the minimum detectable volume change, which in turn influences the scheduling of imaging sessions and the interpretation of observed changes in tumour volume. In this paper, variability is quantified for tumour volume measurements from 3D high-frequency ultrasound images of murine liver metastases. Experimental B16F1 liver metastases were analysed in different size ranges including less than 1 mm 3 , 1-4 mm 3 , 4-8 mm 3 and 8-70 mm 3 . The intra- and inter-observer repeatability was high over a large range of tumour volumes, but the coefficients of variation (COV) varied over the volume ranges. The minimum and maximum intra-observer COV were 4% and 14% for the 1-4 mm 3 and 3 tumours, respectively. For tumour volumes measured by segmenting parallel planes, the maximum inter-slice distance that maintained acceptable measurement variability increased from 100 to 600 μm as tumour volume increased. Comparison of free breathing versus ventilated animals demonstrated that respiratory motion did not significantly change the measured volume. These results enable design of more efficient imaging studies by using the measured variability to estimate the time required to observe a significant change in tumour volume

Evaluation of ASME code flaw analysis procedure using the influence function method for application to PWR primary piping

International Nuclear Information System (INIS)

Hong, S.Y.; Yeater, M.L.

1985-01-01

This paper discusses stress intensity factor calculations and fatigue analysis for a PWR primary coolant piping system. The influence function method is applied to evaluate ASME Code Section XI Appendix A ''analysis of flaw indication'' for the application to a PWR primary piping. Results of the analysis are discussed in detail. (orig.)

Comparison of the outcomes for laparoscopic gastrectomy performed by the same surgeon between a low-volume hospital and a high-volume center.

Science.gov (United States)

Kim, Min Gyu; Kwon, Sung Joon

2014-05-01

The volume-outcome relationship in laparoscopic surgery is controversial. This study was designed to identify differences in laparoscopic gastrectomy outcomes between a low-volume hospital and a high-volume center and to provide guidelines for overcoming the problems associated with a low-volume hospital. From April 2009 to November 2012, one surgeon performed 134 totally laparoscopic distal gastrectomies (TLDGs) at a high-volume center (HVC; ASAN Medical Center) and at a low-volume hospital (LVH; Hanyang University Guri Hospital). All laparoscopically assisted gastrectomies were excluded from this study. During the early period of laparoscopic gastrectomy at the low-volume hospital, TLDG with Roux-en-Y gastrojejunostomy (RYGJ) was performed according to the surgeon's choice. The reconstruction method was classified as gastroduodenostomy (GD) or RYGJ. Early surgical outcomes achieved at the LVH were investigated and compared with those obtained at the HVC. The early surgical outcomes differed significantly between the two hospitals. In particular, the postoperative complication rate for the patients who underwent TLDG RYGJ at the LVH was higher than at the HVC (LVH 15.4 % vs. HVC 0 %; p = 0.037). Furthermore, significant differences were observed in the mean operation time (TLDG GD: LVH 141.0 min vs. HVC 117.4 min, p = 0.001; TLDG RYGJ: LVH 186.3 min vs. HVC 134.6 min, p = 0.009) and length of hospital stay (TLDG GD: LVH 8.1 days vs. HVC 7.2 days, p = 0.044; TLDG RYGJ: LVH 11.5 day vs. HVC 6.8 day, p = 0.009). Although all the operations were performed by one experienced surgeon, the early surgical outcomes differed significantly between the low- and high-volume hospitals. Low-volume hospitals often lack well-trained surgical professionals such as first assistants and scrub nurses. Therefore, the authors recommend that a surgeon who works at an LVH should assess potential personnel shortages and find a solution before operating.

Application of flaw detection methods for detection of fatigue processes in low-alloyed steel

Directory of Open Access Journals (Sweden)

Zbigniew H. śUREK

2007-01-01

Full Text Available The paper presents the investigations conducted in the Fraunhofer Institute (IZFP Saarbrücken by use of a BEMI microscope (BEMI= Barkhausenrausch- und Wirbelstrom-Mikroskopie or Barkhausen Noise and Eddy Current Microscopy. The ability to detect cyclic and contact fatigue load influences has been investigated. The measurement amplitudes obtained with Barkhausen Noise and Eddy Current probes havebeen analysed. Correlation of measurement results and material’s condition has been observed in case of the eddy current mode method for frequencies above 2 MHz (for contact-loaded material samples. Detection of material’s fatigue process (at 80 % fatiguelife in the sample subjected to series of high-cyclic loads has been proven to be practically impossible. Application of flaw detection methods in material fatigue tests requires modification of test methods and use of investigation methods relevant to physical parameters of the investigated material. The magnetic leakage field method, which has been abandoned by many researchers, may be of significant use in the material fatigue assessment and may provide new research prospects.

Enron Flaws In Organizational Architecture And Its Failure

Directory of Open Access Journals (Sweden)

Nguyen

2015-08-01

Full Text Available A series of corporate scandals at the beginning of last decade has given rise to the doubt on the efficiency of corporate governance practice in the United States. Of these scandals the collapse of Enron has exceptionally captured the public concern. It was the once seventh-largest company in the United States 1. It was rated the most innovative large company in America in Fortunes Most Admired Companies survey 2. In August 2000 its stock reached a peak of nearly 70 billion 3. However within a year its stock had become almost useless papers 2. It just was unbelievable for many people. What went wrong Was it due to the failure of corporate governance in general Actually the central factor leading to the collapse of Enron was the failure in its organizational architecture. This paper starts by providing an overview of corporate governance system with an emphasis on the corporate organizational architecture as its important facet. Then it discusses flaws in the organizational architecture of Enron and argues that these eventually led to the breakdown of the whole corporate governance system at Enron. Finally some implications and lessons for the practice of corporate governance are presented.

Influence of partially known parameter on flaw characterization in Eddy Current Testing by using a random walk MCMC method based on metamodeling

International Nuclear Information System (INIS)

Cai, Caifang; Lambert, Marc; Rodet, Thomas

2014-01-01

First, we present the implementation of a random walk Metropolis-within-Gibbs (MWG) sampling method in flaw characterization based on a metamodeling method. The role of metamodeling is to reduce the computational time cost in Eddy Current Testing (ECT) forward model calculation. In such a way, the use of Markov Chain Monte Carlo (MCMC) methods becomes possible. Secondly, we analyze the influence of partially known parameters in Bayesian estimation. The objective is to evaluate the importance of providing more specific prior information. Simulation results show that even partially known information has great interest in providing more accurate flaw parameter estimations. The improvement ratio depends on the parameter dependence and the interest shows only when the provided information is specific enough

RSE-M code progress in the field of examination evaluation and flaw acceptance criteria

International Nuclear Information System (INIS)

Barthelet, B.; Le Delliou, P.; Heliot, J.; Faidy, C.; Drubay, B.

1995-01-01

The RSE-M Code provides rules and requirements for in service inspection of light water cooled nuclear power plants. The code first edition was established by EDF and published in 1990 by AFCEN. In 1992, a second RSE-M project was launched by EDF and FRAMATOME with the objective to address a 1995 edition more completed considering the needs of owners, users, manufacturers and inspectors. This paper focuses on evaluation of examination results and presents the work done in the field of flaw acceptance criteria over the last three years. (author). 5 refs., 3 figs

Comparison of COD, R6, and J-contour integral methods of defect assessment, modified to give critical flaw sizes

International Nuclear Information System (INIS)

Burdekin, F.M.; Turner, C.E.

1982-01-01

A comparative study of the application of different elastic-plastic fracture mechanics methods to the calculation of critical defect sizes in pressure vessels showed widely varying results. The present authors have investigated in detail the reasons for the variations resulting from the use of the CEGB R6, COD design curve, and J-design curve methods to the particular pressure vessel problems. To obtain reasonable agreement between the three methods for the calculation of critical flaw sizes in high stress gradient situations, the published COD method in PD6493 has to be modified to remove its inherent safety factor, and to allow for stress gradients, and a consistent treatment for gross yielding/collapse has to be adopted for all three methods. (author)

The flaw-detected coating and its applications in R&M of aircrafts

Science.gov (United States)

Hu, Feng; Liu, Mabao; Lü, Zhigang

2009-07-01

A monitoring method called ICM (Intelligent Coating Monitoring), which is based mainly on the intelligent coating sensors, has the capability to monitor crack initiation and growth in fatigue test coupons has been suggested in this study. The intelligent coating sensor is normally consisted of three layers: driving layer, sensing layer and protective layer where necessary. Fatigue tests with ICM for various materials demonstrate the capability to detect cracks with lfuel tank of an aircraft), or (ii) to take advantage of early detection and apply less invasive life-extension repairs, as well as reduce interruption of service when flaws are detected. Implementation of ICM is expected to improve fleet management practices and modify damage tolerance assumptions.

Service expectations from high- and low-volume customers in the alcoholic beverage industry

Directory of Open Access Journals (Sweden)

Jacques Beukes

2013-08-01

Research purpose: This research study investigated the relationship between the volume a customer buys from an alcoholic beverage supply company and what influence this volume has on their customer service expectations. Motivation for the study: The main purpose of this study was to evaluate what influence the volume an organisation buys from alcoholic beverage suppliers has on their service quality expectations. Research design, approach and method: A non-probability judgement sample method was used, with a sample size of 220 respondents. The questionnaire requested respondents (high- and low-volume to rank their customer service expectations and opinions with reference to Parasuraman’s service delivery dimensions. Ranking was done using a five-point Likert scale. Main findings: The findings of the study indicated that both the high- and low-volume customers felt that alcoholic beverage supply companies had to deliver on all five service delivery dimensions but failed to do so to full satisfaction. Practical and managerial implications: It is recommended that the alcoholic beverage supply companies should address the problem areas identified in this study to avoid defection of customers. Contribution and value add: This may assist alcoholic beverage supply companies to better understand the customers’ demographic profiles. The study also revealed that the satisfaction level experienced by customers in both sections of the study (high- and low-demand, with a considerable gap between expectations and opinions within the empathy dimension.

Comparison of Weibull strength parameters from flexure and spin tests of brittle materials

Science.gov (United States)

Holland, Frederic A., Jr.; Zaretsky, Erwin V.

1991-01-01

Fracture data from five series of four point bend tests of beam and spin tests of flat annular disks were reanalyzed. Silicon nitride and graphite were the test materials. The experimental fracture strengths of the disks were compared with the predicted strengths based on both volume flaw and surface flaw analyses of four point bend data. Volume flaw analysis resulted in a better correlation between disks and beams in three of the five test series than did surface flaw analysis. The Weibull (moduli) and characteristic gage strengths for the disks and beams were also compared. Differences in the experimental Weibull slopes were not statistically significant. It was shown that results from the beam tests can predict the fracture strength of rotating disks.

High-speed automated NDT device for niobium plate using scanning laser acoustic microscopy

International Nuclear Information System (INIS)

Oravecz, M.G.; Yu, B.Y.; Riney, K.; Kessler, L.W.; Padamsee, H.

1988-01-01

This paper presents a nondestructive testing (NDT) device which rapidly and automatically identifies defects throughout the volume of a 23.4 cm x 23.4 cm x 0.3 cm, pure niobium plate using Scanning Laser Acoustic Microscope (SLAM), high-resolution, 60 MHz, ultrasonic images. A principle advantage of the SLAM technique is that it combines a video scan rate with a high scan density (130 lines/mm at 60 MHz). To automate the inspection system they integrated under computer control the following: the SLAM RS-170/330 video output, a computerized XY plate scanner, a real-time video digitizer/integrator, a computer algorithm for defect detection, a digital mass storage device, and a hardcopy output device. The key element was development of an efficient, reliable defect detection algorithm using a variance filter with a locally determined threshold. This algorithm is responsible for recognizing valid flaws in the midst of random texture. This texture was seen throughout the acoustic images and was caused by the niobium microstructure. The images, as analyzed, contained 128 x 120 pixels with 64 grey levels per pixel. This system allows economical inspection of the large quantities (eg. 100 tons) of material needed for future particle accelerators based on microwave superconductivity. Rapid nondestructive inspection of pure niobium sheet is required because current accelerator performance is largely limited by the quality of commercially available material. Previous work documented critical flaws that are detectable by SLAM techniques. 15 references, 9 figures

Perioperative mortality in cats and dogs undergoing spay or castration at a high-volume clinic.

Science.gov (United States)

Levy, J K; Bard, K M; Tucker, S J; Diskant, P D; Dingman, P A

2017-06-01

High volume spay-neuter (spay-castration) clinics have been established to improve population control of cats and dogs to reduce the number of animals admitted to and euthanazed in animal shelters. The rise in the number of spay-neuter clinics in the USA has been accompanied by concern about the quality of animal care provided in high volume facilities, which focus on minimally invasive, time saving techniques, high throughput and simultaneous management of multiple animals under various stages of anesthesia. The aim of this study was to determine perioperative mortality for cats and dogs in a high volume spay-neuter clinic in the USA. Electronic medical records and a written mortality log were used to collect data for 71,557 cats and 42,349 dogs undergoing spay-neuter surgery from 2010 to 2016 at a single high volume clinic in Florida. Perioperative mortality was defined as deaths occurring in the 24h period starting with the administration of the first sedation or anesthetic drugs. Perioperative mortality was reported for 34 cats and four dogs for an overall mortality of 3.3 animals/10,000 surgeries (0.03%). The risk of mortality was more than twice as high for females (0.05%) as for males (0.02%) (P=0.008) and five times as high for cats (0.05%) as for dogs (0.009%) (P=0.0007). High volume spay-neuter surgery was associated with a lower mortality rate than that previously reported in low volume clinics, approaching that achieved in human surgery. This is likely to be due to the young, healthy population of dogs and cats, and the continuous refinement of techniques based on experience and the skills and proficiency of teams that specialize in a limited spectrum of procedures. Copyright © 2017 Elsevier Ltd. All rights reserved.

Low-load high volume resistance exercise stimulates muscle protein synthesis more than high-load low volume resistance exercise in young men.

Directory of Open Access Journals (Sweden)

Nicholas A Burd

Full Text Available BACKGROUND: We aimed to determine the effect of resistance exercise intensity (%1 repetition maximum-1RM and volume on muscle protein synthesis, anabolic signaling, and myogenic gene expression. METHODOLOGY/PRINCIPAL FINDINGS: Fifteen men (21+/-1 years; BMI=24.1+/-0.8 kg/m2 performed 4 sets of unilateral leg extension exercise at different exercise loads and/or volumes: 90% of repetition maximum (1RM until volitional failure (90FAIL, 30% 1RM work-matched to 90%FAIL (30WM, or 30% 1RM performed until volitional failure (30FAIL. Infusion of [ring-13C6] phenylalanine with biopsies was used to measure rates of mixed (MIX, myofibrillar (MYO, and sarcoplasmic (SARC protein synthesis at rest, and 4 h and 24 h after exercise. Exercise at 30WM induced a significant increase above rest in MIX (121% and MYO (87% protein synthesis at 4 h post-exercise and but at 24 h in the MIX only. The increase in the rate of protein synthesis in MIX and MYO at 4 h post-exercise with 90FAIL and 30FAIL was greater than 30WM, with no difference between these conditions; however, MYO remained elevated (199% above rest at 24 h only in 30FAIL. There was a significant increase in AktSer473 at 24h in all conditions (P=0.023 and mTORSer2448 phosphorylation at 4 h post-exercise (P=0.025. Phosporylation of Erk1/2Tyr202/204, p70S6KThr389, and 4E-BP1Thr37/46 increased significantly (P<0.05 only in the 30FAIL condition at 4 h post-exercise, whereas, 4E-BP1Thr37/46 phosphorylation was greater 24 h after exercise than at rest in both 90FAIL (237% and 30FAIL (312% conditions. Pax7 mRNA expression increased at 24 h post-exercise (P=0.02 regardless of condition. The mRNA expression of MyoD and myogenin were consistently elevated in the 30FAIL condition. CONCLUSIONS/SIGNIFICANCE: These results suggest that low-load high volume resistance exercise is more effective in inducing acute muscle anabolism than high-load low volume or work matched resistance exercise modes.

Use of Master Curve technology for assessing shallow flaws in a reactor pressure vessel material

International Nuclear Information System (INIS)

Bass, Bennett Richard; Taylor, Nigel

2006-01-01

In the NESC-IV project an experimental/analytical program was performed to develop validated analysis methods for transferring fracture toughness data to shallow flaws in reactor pressure vessels subject to biaxial loading in the lower-transition temperature region. Within this scope an extensive range of fracture tests was performed on material removed from a production-quality reactor pressure vessel. The Master Curve analysis of this data is reported and its application to the assessment of the project feature tests on large beam test pieces.

Automated flaw detection scheme for cast austenitic stainless steel weld specimens using Hilbert-Huang transform of ultrasonic phased array data

International Nuclear Information System (INIS)

Khan, Tariq; Majumdar, Shantanu; Udpa, Lalita; Ramuhalli, Pradeep; Crawford, Susan; Diaz, Aaron; Anderson, Michael T.

2012-01-01

The objective of this work is to develop processing algorithms to detect and localize flaws using ultrasonic phased-array data. Data was collected on cast austenitic stainless stell (CASS) weld specimens onloan from the U.S. nuclear power industry' Pressurized Walter Reactor Owners Group (PWROG) traveling specimen set. Each specimen consists of a centrifugally cast stainless stell (CCSS) pipe section welded to a statically cst(SCSS) or wrought (WRSS) section. The paper presents a novel automated flaw detection and localization scheme using low frequency ultrasonic phased array inspection singals from the weld and heat affected zone of the based materials. The major steps of the overall scheme are preprocessing and region of interest (ROI) detection followed by the Hilbert-Huang transform (HHT) of A-scans in the detected ROIs. HHT offers time-frequency-energy distribution for each ROI. The Accumulation of energy in a particular frequency band is used as a classification feature for the particular ROI

Profitable failure: antidepressant drugs and the triumph of flawed experiments.

Science.gov (United States)

McGoey, Linsey

2010-01-01

Drawing on an analysis of Irving Kirsch and colleagues' controversial 2008 article in "PLoS [Public Library of Science] Magazine" on the efficacy of SSRI antidepressant drugs such as Prozac, I examine flaws within the methodologies of randomized controlled trials (RCTs) that have made it difficult for regulators, clinicians and patients to determine the therapeutic value of this class of drug. I then argue, drawing analogies to work by Pierre Bourdieu and Michael Power, that it is the very limitations of RCTs -- their inadequacies in producing reliable evidence of clinical effects -- that help to strengthen assumptions of their superiority as methodological tools. Finally, I suggest that the case of RCTs helps to explore the question of why failure is often useful in consolidating the authority of those who have presided over that failure, and why systems widely recognized to be ineffective tend to assume greater authority at the very moment when people speak of their malfunction.

US evaluation of volume brain lesions produced by high-intensity focused US

International Nuclear Information System (INIS)

Chua, R.V.; Chua, G.T.; Fry, F.J.; Franklin, T.D.; Wills, E.R.; Hastings, J.S.; Sanghui, N.T.

1987-01-01

Eighteen volume brain lesions produced by high-intensity focused US in the right cerebral hemispheres of research canines were evaluated by diagnostic US from immediately after ablation up to 62 days later. Animals were killed and perfused for whole-brain recovery. US evaluation of whole-brain specimens was performed. Histologic analysis of brain sections verified lesion placement, size, and tissue response to US. These sections were compared with US studies for correlation data. Correlation data suggest that US visualization may aid in accurate placement of volume brain lesions and in evaluation of effects of high-intensity focuses US in normal brain

Analysis of the failure performance of internally pressurized piping with surface flaws

International Nuclear Information System (INIS)

Iorio, A.F; Crespi, J.C.

1987-01-01

Due to frequent failures an Atucha I PHWR moderator circuit branch piping, made of stainless steel type AISI 347 (DIN 1.4550), studies have been made, involving the application of several fracture mechanics criteria, in order to determine the conditions of leak-before-break (L.BB) and the critical crack length of the piping. These studies lead to the conclusions that, for a straight pipe of outer diameter of 219 mm and 16 mm wall thickness, with a circumferential flaw and the principal stress being in the bending, the L.BB criteria are satisfied, being the critical crack length of the order of 400 mm. A better mechanical finishing and heat treatment was suggested in order to improve the resistance to crack initiation. (Author)

Preliminary experimental results for a non-intrusive scheme for the detection of flaws in metal pipelines

Science.gov (United States)

Aydin, K.; Shinde, S.; Suhail, M.; Vyas, A.; Zieher, K. W.

2002-05-01

An acoustic pulse echo scheme for non-intrusive detection of flaws in metal pipelines has been investigated in the laboratory. The primary pulse is generated by a pulsed magnetic field enclosing a short section of a free pipe. The detection is by an electrostatic detector surrounding a short section of the pipe. Reflected pulses from thin areas, with a longitudinal extension of about one pipe radius and a reduction of the wall thickness of 40%, can be detected clearly.

Secure data storage by three-dimensional absorbers in highly scattering volume medium

International Nuclear Information System (INIS)

Matoba, Osamu; Matsuki, Shinichiro; Nitta, Kouichi

2008-01-01

A novel data storage in a volume medium with highly scattering coefficient is proposed for data security application. Three-dimensional absorbers are used as data. These absorbers can not be measured by interferometer when the scattering in a volume medium is strong enough. We present a method to reconstruct three-dimensional absorbers and present numerical results to show the effectiveness of the proposed data storage.

Flaw location and characterization in anisotropic materials by ultrasonic spectral analysis

International Nuclear Information System (INIS)

Adler, L.; Cook, K.V.; Simpson, W.A.; Lewis, D.K.

1978-01-01

A method of quantitatively determining size and location of flaws in anisotropic materials such as stainless steel welds is described. In previous work, it was shown that spectral analysis of a broad band ultrasonic pulse scattered from a defect can be used to determine size and orientation in isotropic materials if the velocity of sound in the material is known. In an anisotropic structural material (stainless steel weld, centrifugal cast pipe), the velocity (both shear and longitudinal) is direction-dependent. When anisotropy is not taken into account, defect location and defect size estimation is misjudged. It will be shown that the effect of this structural variation in materials must be considered to obtain the correct size and location of defects by frequency analysis. A theoretical calculation, including anisotropy, of the scattered field from defects will also be presented

Functionality and Performance Visualization of the Distributed High Quality Volume Renderer (HVR)

KAUST Repository

Shaheen, Sara

2012-07-01

Volume rendering systems are designed to provide means to enable scientists and a variety of experts to interactively explore volume data through 3D views of the volume. However, volume rendering techniques are computationally intensive tasks. Moreover, parallel distributed volume rendering systems and multi-threading architectures were suggested as natural solutions to provide an acceptable volume rendering performance for very large volume data sizes, such as Electron Microscopy data (EM). This in turn adds another level of complexity when developing and manipulating volume rendering systems. Given that distributed parallel volume rendering systems are among the most complex systems to develop, trace and debug, it is obvious that traditional debugging tools do not provide enough support. As a consequence, there is a great demand to provide tools that are able to facilitate the manipulation of such systems. This can be achieved by utilizing the power of compute graphics in designing visual representations that reflect how the system works and that visualize the current performance state of the system.The work presented is categorized within the field of software Visualization, where Visualization is used to serve visualizing and understanding various software. In this thesis, a number of visual representations that reflect a number of functionality and performance aspects of the distributed HVR, a high quality volume renderer system that uses various techniques to visualize large volume sizes interactively. This work is provided to visualize different stages of the parallel volume rendering pipeline of HVR. This is along with means of performance analysis through a number of flexible and dynamic visualizations that reflect the current state of the system and enables manipulation of them at runtime. Those visualization are aimed to facilitate debugging, understanding and analyzing the distributed HVR.

Back-end interconnection. A generic concept for high volume manufacturing

Energy Technology Data Exchange (ETDEWEB)

Bosman, J.; Budel, T.; De Kok, C.J.G.M.

2013-10-15

The general method to realize series connection in thin film PV modules is monolithical interconnection through a sequence of laser scribes (P1, P2 and P3) and layer depositions. This method however implies that the deposition processes are interrupted several times, an undesirable situation in high volume processing. In order to eliminate this drawback we focus our developments on the so called 'back-end interconnection concept' in which series interconnection takes place AFTER the deposition of the functional layers of the thin film PV device. The process of making a back-end interconnection combines laser scribing, curing, sintering and inkjet processes. These different processes interacts with each other and are investigated in order to create processing strategies that are robust to ensure high volume production. The generic approach created a technology base that can be applied to any thin film PV technology.

An analytical hierarchical model explaining the robustness and flaw-tolerance of the interlocking barb-barbule structure of bird feathers

Science.gov (United States)

Chen, Qiang; Gorb, Stanislav; Kovalev, Alexander; Li, Zhiyong; Pugno, Nicola

2016-10-01

Feathers can fulfill their aerodynamic function only if the pennaceous vane forms an airfoil stabilized by robust interlocking between barbules. Thus, revealing the robustness of the interlocking mechanical behavior of the barbules is very important to understand the function and long-term resilience of bird feathers. This paper, basing on the small- and large-beam deflection solutions, presents a hierarchical mechanical model for deriving the critical delamination conditions of the interlocking barbules between two adjacent barbs in bird feathers. The results indicate a high robustness and flaw-tolerant design of the structure. This work contributes to the understanding of the mechanical behavior of the robust interlocking barb-barbule structure of the bird feather, and provides a basis for design of feather-inspired materials with robust interlocking mechanism, such as advanced bio-inspired micro-zipping devices.

Mechanical Properties and Brittle Behavior of Silica Aerogels

Directory of Open Access Journals (Sweden)

Thierry Woignier

2015-12-01

Full Text Available Sets of silica gels: aerogels, xerogels and sintered aerogels, have been studied in the objective to understand the mechanical behavior of these highly porous solids. The mechanical behaviour of gels is described in terms of elastic and brittle materials, like glasses or ceramics. The magnitude of the elastic and rupture modulus is several orders of magnitude lower compared to dense glass. The mechanical behaviours (elastic and brittle are related to the same kinds of gel characteristics: pore volume, silanol content and pore size. Elastic modulus depends strongly on the volume fraction of pores and on the condensation reaction between silanols. Concerning the brittleness features: rupture modulus and toughness, it is shown that pores size plays an important role. Pores can be considered as flaws in the terms of fracture mechanics and the flaw size is related to the pore size. Weibull’s theory is used to show the statistical nature of flaw. Moreover, stress corrosion behaviour is studied as a function of environmental conditions (water and alcoholic atmosphere and temperature.

Proposal of reference stress for a surface flaw on a cylindrical component from a review-with-comparison of the local metal loss assessment rule between API 579-1 and the p-M diagram method

International Nuclear Information System (INIS)

Oyamada, Kenji; Konosu, Shinji; Ohno, Takashi

2011-01-01

The Remaining Strength Factor (RSF) approach in Part 5 of API 579-1/ASME FFS-1 is an assessment method for a cylindrical component with a local metal loss based on surface correction factors. Also, reference stress solutions that are applied in the Failure Assessment Diagram (FAD) method for a cylindrical component with a crack-like flaw are provided in Annex D using surface correction factors. In the recently-developed p-M diagram method, the reference stress solution for local metal loss evaluation in a cylindrical component is derived using bulging factors, which are similar but not identical to the surface correction factors used in API 579-1/ASME FFS-1. This paper describes the results of a comparative study among the RSF approach, reference stress solutions for the FAD method, and the p-M diagram method, in terms of plastic collapse evaluation of a cylindrical component. These results were compared with the FEA and experimental results to confirm how these estimated stresses could be validated. This study also involves recommended reference stress solutions for a cylindrical component with a crack-like flaw or a local metal loss, which should be adopted as fitness-for-service rules, and a discussion on the influence of the design margin of the construction code on allowable flaw depth. - Highlights: → We compared local metal loss assessment rule between API 579-1 and the p-M method. → Experiments and FEA verified the p-M estimate stress state around a flaw accurate. → API 579-1 for local metal loss may underestimate stress state for certain conditions. → Existing reference stresses for crack-like flaws may underestimate stress state too. → We propose the reference stress for a surface flaw subjected to pressure and moment.

Do high-volume hospitals and surgeons provide better care in urologic oncology?

Science.gov (United States)

Eastham, James A

2009-01-01

Studies focusing primarily on hospital or surgical volume as a surrogate for surgical experience have found substantial variations in outcomes. Increasing surgical experience has been shown to improve outcomes after multiple procedures, including esophagectomy, pancreatectomy, and primary surgery for colon and breast cancer. More recently, evidence has been presented that surgical volume/experience affects quality of life and cancer control outcomes after urologic oncology procedures. Although most of these data pertain to radical prostatectomy, similar conclusions have been reached for radical cystectomy, retroperitoneal lymph node dissection, and management of renal cell carcinoma. This review highlights data indicating that high-volume surgeons and hospitals provide better care for radical prostatectomy.

Low versus high volume of culture medium during embryo transfer: a randomized clinical trial.

Science.gov (United States)

Sigalos, George Α; Michalopoulos, Yannis; Kastoras, Athanasios G; Triantafyllidou, Olga; Vlahos, Nikos F

2018-04-01

The aim of this prospective randomized control trial was to evaluate if the use of two different volumes (20-25 vs 40-45 μl) of media used for embryo transfer affects the clinical outcomes in fresh in vitro fertilization (IVF) cycles. In total, 236 patients were randomized in two groups, i.e., "low volume" group (n = 118) transferring the embryos with 20-25 μl of medium and "high volume" group (n = 118) transferring the embryos with 40-45 μl of medium. The clinical pregnancy, implantation, and ongoing pregnancy rates were compared between the two groups. No statistically significant differences were observed in clinical pregnancy (46.8 vs 54.3%, p = 0.27), implantation (23.7 vs 27.8%, p = 0.30), and ongoing pregnancy (33.3 vs 40.0%, p = 0.31) rates between low and high volume group, respectively. Higher volume of culture medium to load the embryo into the catheter during embryo transfer does not influence the clinical outcome in fresh IVF cycles. NCT03350646.

Resistance to Corrosion of Reinforcement of High Volume Fly Ash Concrete

International Nuclear Information System (INIS)

Kwon, S. O.; Bae, S. H.; Lee, H. J.; Lee, K. M.; Jung, S. H.

2014-01-01

Due to the increasing of interest about the eco-friendly concrete, it is increased to use concretes containing by-products of industry such as fly ash(FA), ground granulated blast furnace slag(GGBFS), silica fume(SF), and etc. Especially, these are well known for improving the resistances to reinforcement corrosion in concrete and decreasing chloride ion penetration. The purpose of this experimental research is to evaluate the resistance against corrosion of reinforcement of high volume fly ash(HVFA) concrete which is replaced with high volume fly ash for cement volume. For this purpose, the concrete test specimens were made for various strength level and replacement ratio of FA, and then the compressive strength and diffusion coefficient for chloride ion of them were measured for 28, 91, and 182 days, respectively. Also, corrosion monitoring by half cell potential method was carried out for the made lollypop concrete test specimens to detect the time of corrosion initiation for reinforcement in concrete. As a result, it was observed from the test results that the compressive strength of HVFA concrete was decreased with increasing replacement ratio of FA but long-term resistances against reinforcement corrosion and chloride ion penetration of that were increased

Protein-bound toxins: added value in their removal with high convective volumes.

Science.gov (United States)

Abad, Soraya; Vega, Almudena; Quiroga, Borja; Arroyo, David; Panizo, Nayara; Reque, Javier Eduardo; López-Gómez, Juan Manuel

Chronic kidney disease is associated with an increased risk of cardiovascular events. In recent years, protein-bound toxins have become more important due to their association with increased morbidity and mortality, characterised by inadequate clearance during dialysis. The purpose of this study is to assess the influence of high convective volumes on postdilution online haemodiafiltration (OL-HDF) on the removal of medium-sized molecules, small molecules and protein-bound molecules. In forty postdilutional OL-HDF sessions, the reduction rates of toxins of different molecular weights were measured in 13 patients, including protein-bound molecules such as p-cresyl sulphate, indoxyl sulphate and homocysteine. Total convective volume was 28.3 (5.1) litres (range 16.3-38.0 litres). Mean reduction rate of protein-bound molecules was 44.4% (15.7%), 48.7% (14.1%) and 58.6% (8.8%) for p-cresyl sulphate, indoxyl sulphate and homocysteine, respectively. Moreover, a statistically significant direct association was found between the reduction rates of all three molecules, the replacement volume and the Kt/V. High convective volumes during postdilution OL-HDF are associated with increased removal of protein-bound uraemic toxins. Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

High-volume intensive training course: a new paradigm for video-assisted thoracoscopic surgery education.

Science.gov (United States)

Sihoe, Alan D L; Gonzalez-Rivas, Diego; Yang, Timothy Y; Zhu, Yuming; Jiang, Gening

2018-03-27

The emergence of ultra-high-volume centres promises new opportunities for thoracic surgical training. The goal of this study was to investigate the effectiveness of a novel observership course in teaching video-assisted thoracoscopic surgery (VATS) at an ultra-high-volume centre. Two-week courses in VATS at a specialist unit now performing >10 000 major lung resections annually (>50 daily on average) were attended by 230 surgeons from around the world from 2013 to 2016. An online survey preserving responder anonymity was completed by 156 attendees (67.8%). Attendees included 37% from Western Europe, 18% from Eastern Europe and 17% from Latin America. Experience with open thoracic surgery for more than 5 years was reported by 67%, but 79% had less than 5 years of VATS lobectomy experience. During the course, 70% observed over 30 uniportal VATS operations (including 38% observing over 50), and 69% attended an animal wet lab. Although 72% of the responders attended the course less than 12 months ago, the number of ports used (P < 0.001), operation times (P < 0.001) and conversion rates (P < 0.001) reported by the responders were reduced significantly after the course. Improvements in the problem areas of tissue retraction, instrumentation, stapler application and coordination with the assistant during VATS were reported by 56%, 57%, 58% and 53%, respectively. Of those who had attended other VATS courses previously, 87% preferred the training from this high-volume course. High-volume intensive observership training at an ultra-high-volume centre may improve VATS proficiency in a short period of time, and may provide a time-efficient modality for future thoracic surgical training.

Preferential effects of low volume versus high volume replacement with crystalloid fluid in a hemorrhagic shock model in pigs.

Science.gov (United States)

Ponschab, Martin; Schöchl, Herbert; Keibl, Claudia; Fischer, Henrik; Redl, Heinz; Schlimp, Christoph J

2015-10-06

Fluid resuscitation is a core stone of hemorrhagic shock therapy, and crystalloid fluids seem to be associated with lower mortality compared to colloids. However, as redistribution starts within minutes, it has been suggested to replace blood loss with a minimum of a three-fold amount of crystalloids. The hypothesis was that in comparison to high volume (HV), a lower crystalloid volume (LV) achieves a favorable coagulation profile and exerts sufficient haemodynamics in the acute phase of resuscitation. In 24 anaesthetized pigs, controlled arterial blood loss of 50 % of the estimated blood volume was either (n = 12) replaced with a LV (one-fold) or a HV (three-fold) volume of a balanced, acetated crystalloid solution at room temperature. Hemodynamic parameters, dilution effects and coagulation profile by standard coagulation tests and thromboelastometry at baseline and after resuscitation were determined in both groups. LV resuscitation increased MAP significantly less compared to the HV, 61 ± 7 vs. 82 ± 14 mmHg (p controlled blood loss, a one fold LV crystalloid replacement strategy is sufficient to adequately raise blood pressure up to a mean arterial pressure >50 mm Hg. The concept of damage control resuscitation (DCR) with permissive hypotension may be better met by using LV as compared to a three fold HV resuscitation strategy. High volume administration of an acetated balanced crystalloid does not lead to hyperchloraemic acidosis, but may negatively influence clinical parameters, such as higher blood pressure, lower body temperature and impaired coagulation parameters, which could potentially increase bleeding after trauma. Replacement of acute blood loss with just an equal amount of an acetated balanced crystalloid appears to be the preferential treatment strategy in the acute phase after controlled bleeding.

Fatigue flaw growth assessment and inclusion of stratification to the LBB assessment

Energy Technology Data Exchange (ETDEWEB)

Samohyl, P.

1997-04-01

The application of the LBB requires also fatigue flaw growth assessment. This analysis was performed for PWR nuclear power plants types VVER 440/230, VVER 440/213c, VVER 1000/320. Respecting that these NPP`s were designed according to Russian codes that differ from US codes it was needed to compare these approaches. Comparison with our experimental data was accomplished, too. Margins of applicability of the US methods and their modifications for the materials used for construction of Czech and Slovak NPP`s are shown. Computer code accomplishing the analysis according to described method is presented. Some measurement and calculations show that thermal stratifications in horizontal pipelines can lead to additive loads that are not negligible and can be dangerous. An attempt to include these loads induced by steady-state stratification was made.

Diagram Size vs. Layout Flaws: Understanding Quality Factors of UML Diagrams

DEFF Research Database (Denmark)

Störrle, Harald

2016-01-01

, though, is our third goal of extending our analysis aspects of diagram quality. Method: We improve our definition of diagram size and add a (provisional) definition of diagram quality as the number of topographic layout flaws. We apply these metrics on 60 diagrams of the five most commonly used types...... of UML diagram. We carefully analyze the structure of our diagram samples to ensure representativeness. We correlate diagram size and layout quality with modeler performance data obtained in previous experiments. The data set is the largest of its kind (n-156). Results: We replicate earlier findings......, and extend them to two new diagram types. We provide an improved definition of diagram size, and provide a definition of topographic layout quality, which is one more step towards a comprehensive definition of diagram quality as such. Both metrics are shown to be objectively applicable. We quantify...

High Energy Performance Tests of Large Volume LaBr{sub 3}:Ce Detector

Energy Technology Data Exchange (ETDEWEB)

Naqvi, A.A.; Gondal, M.A.; Khiari, F.Z.; Dastageer, M.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Maslehuddin, M.M. [Center for Engineering Research, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

2015-07-01

High energy prompt gamma ray tests of a large volume cylindrical 100 mm x 100 mm (height x diameter) LaBr{sub 3}:Ce detector were carried out using a portable neutron generator-based Prompt Gamma Neutron Activation Analysis (PGNAA) setup. In this study prompt gamma-rays yield were measured from water samples contaminated with toxic elements such nickel, chromium and mercury compounds with gamma ray energies up to 10 MeV. The experimental yield of prompt gamma-rays from toxic elements were compared with the results of Monte Carlo calculations. In spite of its higher intrinsic background due to its larger volume, an excellent agreement between the experimental and calculated yields of high energy gamma-rays from Ni, Cr and Hg samples has been achieved for the large volume LaBr{sub 3}:Ce detector. (authors)

Modelling molecular adsorption on charged or polarized surfaces: a critical flaw in common approaches.

Science.gov (United States)

Bal, Kristof M; Neyts, Erik C

2018-03-28

A number of recent computational material design studies based on density functional theory (DFT) calculations have put forward a new class of materials with electrically switchable chemical characteristics that can be exploited in the development of tunable gas storage and electrocatalytic applications. We find systematic flaws in almost every computational study of gas adsorption on polarized or charged surfaces, stemming from an improper and unreproducible treatment of periodicity, leading to very large errors of up to 3 eV in some cases. Two simple corrective procedures that lead to consistent results are proposed, constituting a crucial course correction to the research in the field.

A reliable and consistent production technology for high volume compacted graphite iron castings

Directory of Open Access Journals (Sweden)

Liu Jincheng

2014-07-01

Full Text Available The demands for improved engine performance, fuel economy, durability, and lower emissions provide a continual challenge for engine designers. The use of Compacted Graphite Iron (CGI has been established for successful high volume series production in the passenger vehicle, commercial vehicle and industrial power sectors over the last decade. The increased demand for CGI engine components provides new opportunities for the cast iron foundry industry to establish efficient and robust CGI volume production processes, in China and globally. The production window range for stable CGI is narrow and constantly moving. Therefore, any one step single addition of magnesium alloy and the inoculant cannot ensure a reliable and consistent production process for complicated CGI engine castings. The present paper introduces the SinterCast thermal analysis process control system that provides for the consistent production of CGI with low nodularity and reduced porosity, without risking the formation of flake graphite. The technology is currently being used in high volume Chinese foundry production. The Chinese foundry industry can develop complicated high demand CGI engine castings with the proper process control technology.

Methodological Flaws, Conflicts of Interest, and Scientific Fallacies: Implications for the Evaluation of Antidepressants' Efficacy and Harm.

Science.gov (United States)

Hengartner, Michael P

2017-01-01

In current psychiatric practice, antidepressants are widely and with ever-increasing frequency prescribed to patients. However, several scientific biases obfuscate estimates of antidepressants' efficacy and harm, and these are barely recognized in treatment guidelines. The aim of this mini-review is to critically evaluate the efficacy and harm of antidepressants for acute and maintenance treatment with respect to systematic biases related to industry funding and trial methodology. Narrative review based on a comprehensive search of the literature. It is shown that the pooled efficacy of antidepressants is weak and below the threshold of a minimally clinically important change once publication and reporting biases are considered. Moreover, the small mean difference in symptom reductions relative to placebo is possibly attributable to observer effects in unblinded assessors and patient expectancies. With respect to trial dropout rates, a hard outcome not subjected to observer bias, no difference was observed between antidepressants and placebo. The discontinuation trials on the efficacy of antidepressants in maintenance therapy are systematically flawed, because in these studies, spontaneous remitters are excluded, whereas half of all patients who remitted on antidepressants are abruptly switched to placebo. This can cause a severe withdrawal syndrome that is easily misdiagnosed as a relapse when assessed on subjective symptom rating scales. In accordance, the findings of naturalistic long-term studies suggest that maintenance therapy has no clear benefit, and non-drug users do not show increased recurrence rates. Moreover, a growing body of evidence from hundreds of randomized controlled trials suggests that antidepressants cause suicidality, but this risk is underestimated because data from industry-funded trials are systematically flawed. Unselected, population-wide observational studies indicate that depressive patients who use antidepressants are at an increased

Methodological Flaws, Conflicts of Interest, and Scientific Fallacies: Implications for the Evaluation of Antidepressants’ Efficacy and Harm

Directory of Open Access Journals (Sweden)

Michael P. Hengartner

2017-12-01

Full Text Available BackgroundIn current psychiatric practice, antidepressants are widely and with ever-increasing frequency prescribed to patients. However, several scientific biases obfuscate estimates of antidepressants’ efficacy and harm, and these are barely recognized in treatment guidelines. The aim of this mini-review is to critically evaluate the efficacy and harm of antidepressants for acute and maintenance treatment with respect to systematic biases related to industry funding and trial methodology.MethodsNarrative review based on a comprehensive search of the literature.ResultsIt is shown that the pooled efficacy of antidepressants is weak and below the threshold of a minimally clinically important change once publication and reporting biases are considered. Moreover, the small mean difference in symptom reductions relative to placebo is possibly attributable to observer effects in unblinded assessors and patient expectancies. With respect to trial dropout rates, a hard outcome not subjected to observer bias, no difference was observed between antidepressants and placebo. The discontinuation trials on the efficacy of antidepressants in maintenance therapy are systematically flawed, because in these studies, spontaneous remitters are excluded, whereas half of all patients who remitted on antidepressants are abruptly switched to placebo. This can cause a severe withdrawal syndrome that is easily misdiagnosed as a relapse when assessed on subjective symptom rating scales. In accordance, the findings of naturalistic long-term studies suggest that maintenance therapy has no clear benefit, and non-drug users do not show increased recurrence rates. Moreover, a growing body of evidence from hundreds of randomized controlled trials suggests that antidepressants cause suicidality, but this risk is underestimated because data from industry-funded trials are systematically flawed. Unselected, population-wide observational studies indicate that depressive patients

Possibility of obtaining reliable information on component safety by means of large-scale tensile samples with Orowan-Soete flaws

International Nuclear Information System (INIS)

Aurich, D.; Wobst, K.; Kafka, H.

1984-01-01

The aim of the paper is to review the present knowledge regarding the ability of wide plate tensile specimen with saw cut trough center flaws of providing accurate information on component reliability; it points out the advantages and disadvantages of this specimen geometries. The effect of temperature, specimen geometry, ligament size and notch radii are discussed in comparison with other specimen geometries. This is followed by a comparison of the results of such tests with tests on inside stressed tanks. Conclusions: wide-plate tensile specimen are generally appropriate for assessing welded joints. However, they result in a more favourable evaluation of low-toughness steels from the point of view of crack growth than of high-toughness and soft steels in case of stresses with incipient cracks, as compared with the results obtained with three-point bending samples. (orig.) [de

Reduction on high level radioactive waste volume and geological repository footprint with high burn-up and high thermal efficiency of HTGR

Energy Technology Data Exchange (ETDEWEB)

Fukaya, Yuji, E-mail: fukaya.yuji@jaea.go.jp; Nishihara, Tetsuo

2016-10-15

Highlights: • We evaluate the number of canisters and its footprint for HTGR. • We proposed new waste loading method for direct disposal of HTGR. • HTGR can significantly reduce HLW volume compared with LWR. - Abstract: Reduction on volume of High Level radioactive Waste (HLW) and footprint in a geological repository due to high burn-up and high thermal efficiency of High Temperature Gas-cooled Reactor (HTGR) has been investigated. A helium-cooled and graphite-moderated commercial HTGR was designed as a Gas Turbine High Temperature Reactor (GTHTR300), and that has particular features such as significantly high burn-up of approximately 120 GWd/t, high thermal efficiency around 50%, and pin-in-block type fuel. The pin-in-block type fuel was employed to reduce processed graphite volume in reprocessing. By applying the feature, effective waste loading method for direct disposal is proposed in this study. By taking into account these feature, the number of HLW canister generations and its repository footprint are evaluated by burn-up fuel composition, thermal calculation and criticality calculation in repository. As a result, it is found that the number of canisters and its repository footprint per electricity generation can be reduced by 60% compared with Light Water Reactor (LWR) representative case for direct disposal because of the higher burn-up, higher thermal efficiency, less TRU generation, and effective waste loading proposed in this study for HTGR. But, the reduced ratios change to 20% and 50% if the long term durability of LWR canister is guaranteed. For disposal with reprocessing, the number of canisters and its repository footprint per electricity generation can be reduced by 30% compared with LWR because of the 30% higher thermal efficiency of HTGR.

Trading volume and the number of trades : a comparative study using high frequency data

OpenAIRE

Izzeldin, Marwan

2007-01-01

Trading volume and the number of trades are both used as proxies for market activity, with disagreement as to which is the better proxy for market activity. This paper investigates this issue using high frequency data for Cisco and Intel in 1997. A number of econometric methods are used, including GARCH augmented with lagged trading volume and number of trades, tests based on moment restrictions, regression analysis of volatility on volume and trades, normality of returns when standardized by...

High-pitch dual-source CT coronary angiography with low volumes of contrast medium

International Nuclear Information System (INIS)

Lembcke, Alexander; Hein, Patrick A.; Knobloch, Gesine; Durmus, Tahir; Hamm, Bernd; Schwenke, Carsten; Huppertz, Alexander

2014-01-01

To assess the effect of lower volumes of contrast medium (CM) on image quality in high-pitch dual-source computed tomography coronary angiography (CTCA). One-hundred consecutive patients (body weight 65-85 kg, stable heart rate ≤65 bpm, cardiac index ≥2.5 L/min/m 2 ) referred for CTCA were prospectively enrolled. Patients were randomly assigned to one of five groups of different CM volumes (G 30 , 30 mL; G 40 , 40 mL; G 50 , 50 mL; G 60 , 60 mL; G 70 , 70 mL; flow rate 5 mL/s each, iodine content 370 mg/mL). Attenuation within the proximal and distal coronary artery segments was analysed. Mean attenuation for men and women ranged from 345.0 and 399.1 HU in G 30 to 478.2 and 571.8 HU in G 70 . Mean attenuation values were higher in groups with higher CM volumes (P 30 , G 40 , G 50 , G 60 and G 70 were 89 %, 95 %, 98 %, 98 % and 99 %. CM volume of 30 mL in women and 40 mL in men proved to be sufficient to guarantee attenuation of at least 300 HU. In selected patients high-pitch dual-source CTCA can be performed with CM volumes of 40 mL in men or 30 mL in women. (orig.)

FDAAA legislation is working, but methodological flaws undermine the reliability of clinical trials: a cross-sectional study

OpenAIRE

Douglas H. Marin dos Santos; Álvaro N. Atallah

2015-01-01

The relationship between clinical research and the pharmaceutical industry has placed clinical trials in jeopardy. According to the medical literature, more than 70% of clinical trials are industry-funded. Many of these trials remain unpublished or have methodological flaws that distort their results. In 2007, it was signed into law the Food and Drug Administration Amendments Act (FDAAA), aiming to provide publicly access to a broad range of biomedical information to be made available on the ...

The current status of emergency operations at a high-volume cancer center.

Science.gov (United States)

Komori, Koji; Kimura, Kenya; Kinoshita, Takashi; Ito, Seiji; Abe, Tetsuya; Senda, Yoshiki; Misawa, Kazunari; Ito, Yuichi; Uemura, Norihisa; Natsume, Seiji; Kawai, Ryosuke; Kawakami, Jiro; Asano, Tomonari; Iwata, Yoshinori; Kurahashi, Shintaro; Tsutsuyama, Masayuki; Shigeyoshi, Itaru; Shimizu, Yasuhiro

2014-01-01

This study aimed to assess the pathogenic causes, clinical conditions, surgical procedures, in-hospital mortality, and operative death associated with emergency operations at a high-volume cancer center. Although many reports have described the contents, operative procedures, and prognosis of elective surgeries in high-volume cancer centers, emergency operations have not been studied in sufficient detail. We retrospectively enrolled 28 consecutive patients who underwent emergency surgery. Cases involving operative complications were excluded. The following surgical procedures were performed during emergency operations: closure in 3 cases (10.7%), diversion in 22 cases (78.6%), ileus treatment in 2 cases (7.1%), and hemostasis in 1 case (3.6%). Closure alone was performed only once for peritonitis. Diversion was performed in 17 cases (77.3%) of peritonitis, 4 cases (18.2%) of stenosis of the gastrointestinal tract, and 1 case (4.5%) of bleeding. There was a significant overall difference (P = 0.001). The frequency of emergency operations was very low at a high-volume cancer center. However, the recent shift in treatment approaches toward nonoperative techniques may enhance the status of emergency surgical procedures. The results presented in this study will help prepare for emergency situations and resolve them as quickly and efficiently as possible.

Automated high speed volume computed tomography for inline quality control

International Nuclear Information System (INIS)

Hanke, R.; Kugel, A.; Troup, P.

2004-01-01

Increasing complexity of innovative products as well as growing requirements on quality and reliability call for more detailed knowledge about internal structures of manufactured components rather by 100 % inspection than just by sampling test. A first-step solution, like radioscopic inline inspection machines, equipped with automated data evaluation software, have become state of the art in the production floor during the last years. However, these machines provide just ordinary two-dimensional information and deliver no volume data e.g. to evaluate exact position or shape of detected defects. One way to solve this problem is the application of X-ray computed tomography (CT). Compared to the performance of the first generation medical scanners (scanning times of many hours), today, modern Volume CT machines for industrial applications need about 5 minutes for a full object scan depending on the object size. Of course, this is still too long to introduce this powerful method into the inline production quality control. In order to gain acceptance, the scanning time including subsequent data evaluation must be decreased significantly and adapted to the manufacturing cycle times. This presentation demonstrates the new technical set up, reconstruction results and the methods for high-speed volume data evaluation of a new fully automated high-speed CT scanner with cycle times below one minute for an object size of less than 15 cm. This will directly create new opportunities in design and construction of more complex objects. (author)

Analysis of the high water wave volume for the Sava River near Zagreb

Science.gov (United States)

Trninic, Dusan

2010-05-01

The paper analyses volumes of the Sava River high water waves near Zagreb during the period: 1926-2008 (N = 83 years), which is needed for more efficient control of high and flood waters. The primary Sava flood control structures in the City of Zagreb are dikes built on both riverbanks, and the Odra Relief Canal with lateral spillway upstream from the City of Zagreb. Intensive morphological changes in the greater Sava area near Zagreb, and anthropological and climate variations and changes at the Sava catchment up to the Zagreb area require detailed analysis of the water wave characteristics. In one analysis, maximum annual volumes are calculated for high water waves with constant duration of: 10, 20, 30, 40, 50 and 60 days. Such calculations encompass total quantity of water (basic and surface runoff). The log Pearson III distribution is adapted for this series of maximum annual volumes. Based on the results obtained, the interrelations are established between the wave volume as function of duration and occurrence probability. In addition to the analysis of maximum volumes of constant duration, it is interesting to carry out the analyses of maximum volume in excess of the reference discharge since it is very important for the flood control. To determine the reference discharges, a discharge of specific duration is used from an average discharge duration curve. The adopted reference discharges have durations of 50, 40, 30, 20 and 10%. Like in the previous case, log Pearson III distribution is adapted to the maximum wave data series. For reference discharge Q = 604 m3/s (duration 10%), a linear trend is calculated of maximum annual volumes exceeding the reference discharge for the Sava near Zagreb during the analyzed period. The analysis results show a significant decrease trend. A similar analysis is carried out for the following three reference discharges: regular flood control measures at the Sava near Zagreb, which are proclaimed when the water level is 350 cm

Flaws in design, analysis and interpretation of Pfizer's antifungal trials of voriconazole and uncritical subsequent quotations.

Science.gov (United States)

Jørgensen, Karsten J; Johansen, Helle Krogh; Gøtzsche, Peter C

2006-01-19

We have previously described how a series of trials sponsored by Pfizer of its antifungal drug, fluconazole, in cancer patients with neutropenia handicapped the control drug, amphotericin B, by flaws in design and analysis. We describe similar problems in two pivotal trials of Pfizer's new antifungal agent, voriconazole, published in a prestigious journal. In a non-inferiority trial, voriconazole was significantly inferior to liposomal amphothericin B, but the authors concluded that voriconazole was a suitable alternative. The second trial used amphothericin B deoxycholate as comparator, but handicapped the drug by not requiring pre-medication to reduce infusion-related toxicity or substitution with electrolytes and fluid to reduce nephrotoxicity, although the planned duration of treatment was 84 days. Voriconazole was given for 77 days on average, but the comparator for only 10 days, which precludes a meaningful comparison. In a random sample of 50 references to these trials, we found that the unwarranted conclusions were mostly uncritically propagated. It was particularly surprising that relevant criticism raised by the FDA related to the first trial was only quoted once, and that none of the articles noted the obvious flaws in the design of the second trial. We suggest that editors ensure that the abstract reflects fairly on the remainder of the paper, and that journals do not impose any time limit for accepting letters that point out serious weaknesses in a study that have not been noted before.

Sampling flies or sampling flaws? Experimental design and inference strength in forensic entomology.

Science.gov (United States)

Michaud, J-P; Schoenly, Kenneth G; Moreau, G

2012-01-01

Forensic entomology is an inferential science because postmortem interval estimates are based on the extrapolation of results obtained in field or laboratory settings. Although enormous gains in scientific understanding and methodological practice have been made in forensic entomology over the last few decades, a majority of the field studies we reviewed do not meet the standards for inference, which are 1) adequate replication, 2) independence of experimental units, and 3) experimental conditions that capture a representative range of natural variability. Using a mock case-study approach, we identify design flaws in field and lab experiments and suggest methodological solutions for increasing inference strength that can inform future casework. Suggestions for improving data reporting in future field studies are also proposed.

Fetal lung volume measurement by MRI with high-speed imaging systems

Energy Technology Data Exchange (ETDEWEB)

Osada, Hisao; Kaku, Kenshi [Chiba Univ. (Japan). Hospital

2002-08-01

Although ultrasonography is widely used for fetal morphologic observation, magnetic resonance imaging (MRI) has gained popularity as a new prenatal diagnostic method with recent introduction of high-speed imaging systems. Infants with lung hypoplasia affecting respiratory function require intensive management starting immediately after birth. Therefore, accurate prenatal differential diagnosis and severity evaluation are extremely important for these fetuses. The aim of this study is to measure fetal lung volume using a computer-based, three-dimensional MRI imaging system and to evaluate the possibility of clinical applications of this procedure. A total of 96 fetuses were evaluated, all were morphologically abnormal, and MRI was done for advanced assessment from 24 to 39 weeks gestation. Three-directional views of fetal chest were imaged by Signa Horizon, 1.5 Tesla, version 5.6 (General Electronics) with the following conditions; coil: TORSO coil, sequence: SSFSE (single shot fast spin echo), slice thickness: 5 mm, and imaging speed: 2 seconds/slice. To calculate the lung volume and create three-dimensional image, the lung area in each slice was traced out, then multiplied using computer image processing. Simultaneously, the volumes of all slices were summed to give the volume of each lung. Linear regression analysis and analysis of covariance (ANCOVA) were used for statistical analyses. In all cases, clear images were obtained, and were adequate for three-dimensional evaluation of the fetal lung. Thirty-five fetuses had poor outcomes, such as intrauterine fetal death, neonatal death, and intensive respiratory care. Regression lines of lung volume versus gestational week were calculated for these fetuses with poor outcome and 61 other fetuses with good outcome. ANCOVA, with gestational week as a covariant, revealed a significant intergroup difference in the lung volume (p<0.001). Similarly, regression lines of lung volume versus fetal body weight estimated by

Fatigue test results of straight pipe with flaws in inner surface

International Nuclear Information System (INIS)

Shibata, Katsuyuki; Oba, Toshihiro; Kawamura, Takaichi; Yokoyama, Norio; Miyazono, Shohachiro

1981-01-01

Fatigue and fracture tests of piping models with flaws in the inner surface were carried out to investigate the fatigue crack growth, coalescence of multiple cracks and fracture behavior. Two straight test pipes with and without weldment in the test section of SUS304L stainless steel were tested under almost the same test conditions. Three artificial defects were machined in the inner surface of the test section of the test pipes. The fatigue test were performed untill the cracks coalesced and grew through the thickness. Subsequently, a static load was imposed on test pipe which contained a large crack in the test section. The test results show that the fatigue crack growth is slower than that predicted by the method specified in the Section XI of ASME Boiler and Pressure Vessel Code, and that the test pipes can endure more than the static load of 3Sm without an unstable fracture. (author)

Gun Shows and Gun Violence: Fatally Flawed Study Yields Misleading Results

Science.gov (United States)

Hemenway, David; Webster, Daniel; Pierce, Glenn; Braga, Anthony A.

2010-01-01

A widely publicized but unpublished study of the relationship between gun shows and gun violence is being cited in debates about the regulation of gun shows and gun commerce. We believe the study is fatally flawed. A working paper entitled “The Effect of Gun Shows on Gun-Related Deaths: Evidence from California and Texas” outlined this study, which found no association between gun shows and gun-related deaths. We believe the study reflects a limited understanding of gun shows and gun markets and is not statistically powered to detect even an implausibly large effect of gun shows on gun violence. In addition, the research contains serious ascertainment and classification errors, produces results that are sensitive to minor specification changes in key variables and in some cases have no face validity, and is contradicted by 1 of its own authors’ prior research. The study should not be used as evidence in formulating gun policy. PMID:20724672

Effect of high and low ultrafiltration volume during hemodialysis on relative blood volume

NARCIS (Netherlands)

Dasselaar, JJ; de Jong, PE; Huisman, RM; Franssen, CFM

2006-01-01

Achieving an optimal posthemodialysis hydration status may be difficult because objective criteria for dry weight are lacking. Both relative blood volume changes (Delta RBV) at the end of hemodialysis and Delta RBV normalized for ultrafiltration volume (Delta RBV/UF ratio) have been reported to

Lean Production Control at a High-Variety, Low-Volume Parts Manufacturer

NARCIS (Netherlands)

Bokhorst, Jos A. C.; Slomp, Jannes

2010-01-01

Eaton Electric General Supplies, a parts manufacturing unit that supplies parts for Eaton's electrical business unit, implemented several lean control elements in its high-variety, low-volume production units. These control elements include a constant work-in-process mechanism to limit and control

Robust and reliable banknote authentification and print flaw detection with opto-acoustical sensor fusion methods

Science.gov (United States)

Lohweg, Volker; Schaede, Johannes; Türke, Thomas

2006-02-01

The authenticity checking and inspection of bank notes is a high labour intensive process where traditionally every note on every sheet is inspected manually. However with the advent of more and more sophisticated security features, both visible and invisible, and the requirement of cost reduction in the printing process, it is clear that automation is required. As more and more print techniques and new security features will be established, total quality security, authenticity and bank note printing must be assured. Therefore, this factor necessitates amplification of a sensorial concept in general. We propose a concept for both authenticity checking and inspection methods for pattern recognition and classification for securities and banknotes, which is based on the concept of sensor fusion and fuzzy interpretation of data measures. In the approach different methods of authenticity analysis and print flaw detection are combined, which can be used for vending or sorting machines, as well as for printing machines. Usually only the existence or appearance of colours and their textures are checked by cameras. Our method combines the visible camera images with IR-spectral sensitive sensors, acoustical and other measurements like temperature and pressure of printing machines.

A flexible and accurate digital volume correlation method applicable to high-resolution volumetric images

Science.gov (United States)

Pan, Bing; Wang, Bo

2017-10-01

Digital volume correlation (DVC) is a powerful technique for quantifying interior deformation within solid opaque materials and biological tissues. In the last two decades, great efforts have been made to improve the accuracy and efficiency of the DVC algorithm. However, there is still a lack of a flexible, robust and accurate version that can be efficiently implemented in personal computers with limited RAM. This paper proposes an advanced DVC method that can realize accurate full-field internal deformation measurement applicable to high-resolution volume images with up to billions of voxels. Specifically, a novel layer-wise reliability-guided displacement tracking strategy combined with dynamic data management is presented to guide the DVC computation from slice to slice. The displacements at specified calculation points in each layer are computed using the advanced 3D inverse-compositional Gauss-Newton algorithm with the complete initial guess of the deformation vector accurately predicted from the computed calculation points. Since only limited slices of interest in the reference and deformed volume images rather than the whole volume images are required, the DVC calculation can thus be efficiently implemented on personal computers. The flexibility, accuracy and efficiency of the presented DVC approach are demonstrated by analyzing computer-simulated and experimentally obtained high-resolution volume images.

Processing ultrasonic inspection data from multiple scan patterns for turbine rotor weld build-up evaluations

Science.gov (United States)

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

2015-03-01

The study presents a data processing methodology for weld build-up using multiple scan patterns. To achieve an overall high probability of detection for flaws with different orientations, an inspection procedure with three different scan patterns is proposed. The three scan patterns are radial-tangential longitude wave pattern, axial-radial longitude wave pattern, and tangential shear wave pattern. Scientific fusion of the inspection data is implemented using volume reconstruction techniques. The idea is to perform spatial domain forward data mapping for all sampling points. A conservative scheme is employed to handle the case that multiple sampling points are mapped to one grid location. The scheme assigns the maximum value for the grid location to retain the largest equivalent reflector size for the location. The methodology is demonstrated and validated using a realistic ring of weld build-up. Tungsten balls and bars are embedded to the weld build-up during manufacturing process to represent natural flaws. Flat bottomed holes and side drilled holes are installed as artificial flaws. Automatic flaw identification and extraction are demonstrated. Results indicate the inspection procedure with multiple scan patterns can identify all the artificial and natural flaws.

The Seductive-Plausibility of Patent Hold-Up Myths — A Flawed Historiography of Patents

DEFF Research Database (Denmark)

Howells, John; Katznelson, Ron D

In previous work we have shown that a flawed historiography of patents continues to be the basis for patent policy advocacy. We set out objective standards of evidence that allegations of development block due to assertion of patents must meet. We show the extent of the errors in the historical...... record in the aircraft, automobile, radio and incandescent lamp technologies. We then evaluate how they measure against the objective standards. We find many simple errors and that an absence of indicia of development block characterise scholarship alleging that assertion of patents blocked development...... of multiple case studies subjected to such standards justifies the rebuttable presumption that “pioneer patents have never blocked development”....

MAY THE HIGH-DEGREE SATISFYING UNREASONABLE REQUIREMENT ALSO MEANS THE GOOD QUALITY: FIVE BIG FLAWS IN THE SUBJECTIVE DEFINITION OF QUALITY AND THEIR SOLUTION

Directory of Open Access Journals (Sweden)

Runsheng Tu

2011-06-01

Full Text Available J. M. Juran's subjective quality definition of "quality is degree to which a set of inherent characteristics fulfils requirements" and the account have five big inherent problems: "to disturb the language order", "to violate the objective of the standardized work", "the dependence to the subjective being too strong, to disobey the objectivity principle", "to be short of the enthusiastic limit", "to be possible to reduce the requirement through the reduction, to improve the quality", "to be possible provides the reason theoretically for the fake and shoddy manufacturer and the person whose quality is bad", "to have the suspicion of circular definition". The method to treat the wound is establishing the definition of "quality is the positive degree". This definition of quality both has guaranteed the positive connotation of J. M. Juran's quality definition and has cured the flaws of J. M. Juran's quality definition, but also has promulgated the condition of the symmetry and the connection between quality and value.

Development of alkali activated cements and concrete mixture design with high volumes of red mud

OpenAIRE

Krivenko, Pavel; Kovalchuk, Oleksandr; Pasko, Anton; Croymans, Tom; Hutt, Mikael; Lutter, Guillaume; Vandevenne, Niels; Schreurs, Sonja; Schroeyers, Wouter

2017-01-01

Dedicated cement compositions were formulated to enable the incorporation of large volume fractions of red mud in alkali activated cements, taking into account the role of the aluminosilicate phase in the processes of hydration and hardening. High volume red mud alkali activated cements were synthesized using a proper combination of red mud, low basic aluminosilicate compounds with a glass phase (blast-furnace slag) and additives selected from high-basic Ca-containing cements with a crystalli...

High-volume ovarian cancer care: survival impact and disparities in access for advanced-stage disease.

Science.gov (United States)

Bristow, Robert E; Chang, Jenny; Ziogas, Argyrios; Randall, Leslie M; Anton-Culver, Hoda

2014-02-01

To characterize the impact of hospital and physician ovarian cancer case volume on survival for advanced-stage disease and investigate socio-demographic variables associated with access to high-volume providers. Consecutive patients with stage IIIC/IV epithelial ovarian cancer (1/1/96-12/31/06) were identified from the California Cancer Registry. Disease-specific survival analysis was performed using Cox-proportional hazards model. Multivariate logistic regression analyses were used to evaluate for differences in access to high-volume hospitals (HVH) (≥20 cases/year), high-volume physicians (HVP) (≥10 cases/year), and cross-tabulations of high- or low-volume hospital (LVH) and physician (LVP) according to socio-demographic variables. A total of 11,865 patients were identified. The median ovarian cancer-specific survival for all patients was 28.2 months, and on multivariate analysis the HVH/HVP provider combination (HR = 1.00) was associated with superior ovarian cancer-specific survival compared to LVH/LVP (HR = 1.31, 95%CI = 1.16-1.49). Overall, 2119 patients (17.9%) were cared for at HVHs, and 1791 patients (15.1%) were treated by HVPs. Only 4.3% of patients received care from HVH/HVP, while 53.1% of patients were treated by LVH/LVP. Both race and socio-demographic characteristics were independently associated with an increased likelihood of being cared for by the LVH/LVP combination and included: Hispanic race (OR = 1.72, 95%CI = 1.22-2.42), Asian/Pacific Islander race (OR = 1.57, 95%CI = 1.07-2.32), Medicaid insurance (OR = 2.51, 95%CI = 1.46-4.30), and low socioeconomic status (OR = 2.84, 95%CI = 1.90-4.23). Among patients with advanced-stage ovarian cancer, the provider combination of HVH/HVP is an independent predictor of improved disease-specific survival. Access to high-volume ovarian cancer providers is limited, and barriers are more pronounced for patients with low socioeconomic status, Medicaid insurance, and racial minorities. Copyright © 2013

Assessment of crack-like flaws - Comparison of procedures in BS 7910, API 579-1/ASME FFS-1, RSE-M AND FITNET

International Nuclear Information System (INIS)

Chaudouet, A.

2007-01-01

Among all Fitness For Service Codes enabling to assess flaws in metallic structures and to evaluate their remaining life, new editions of the most important ones at the international level have been issued recently. The latest edition of BS 7910 in United Kingdom has been released in October 2005. In the USA, API and ASME have edited a new standard in 2007, API579-1/ASME FFS-1, dedicated to pressure equipment. In France, the rules concerning the of Light Water Reactors, RSE-M, have been updated in 2005. Finally, in Europe, the FITNET network is writing a document based on BS 7910 but extended with the most recent results in this domain. Rules given in these documents to assess crack-like flaws with respect to fracture and fatigue propagation are presented. They are compared in order to point out the most interesting aspects of each ones and to identify those which could be generalized. An example assessed with the above mentioned 'Codes' enlightens the differences in the results with respect to the 'Code' used. (author) [fr

High-level waste borosilicate glass: A compendium of corrosion characteristics. Volume 3

International Nuclear Information System (INIS)

Cunnane, J.C.

1994-03-01

The objective of this document is to summarize scientific information pertinent to evaluating the extent to which high-level waste borosilicate glass corrosion and the associated radionuclide release processes are understood for the range of environmental conditions to which waste glass may be exposed in service. Alteration processes occurring within the bulk of the glass (e.g., devitrification and radiation-induced changes) are discussed insofar as they affect glass corrosion. Volume III contains a bibliography of glass corrosion studies, including studies that are not cited in Volumes I and II

High-level waste borosilicate glass: A compendium of corrosion characteristics. Volume 3

Energy Technology Data Exchange (ETDEWEB)

Cunnane, J.C. [comp.; Bates, J.K.; Bradley, C.R. [Argonne National Lab., IL (United States)] [and others

1994-03-01

The objective of this document is to summarize scientific information pertinent to evaluating the extent to which high-level waste borosilicate glass corrosion and the associated radionuclide release processes are understood for the range of environmental conditions to which waste glass may be exposed in service. Alteration processes occurring within the bulk of the glass (e.g., devitrification and radiation-induced changes) are discussed insofar as they affect glass corrosion. Volume III contains a bibliography of glass corrosion studies, including studies that are not cited in Volumes I and II.

High-pitch dual-source CT coronary angiography with low volumes of contrast medium

Energy Technology Data Exchange (ETDEWEB)

Lembcke, Alexander; Hein, Patrick A.; Knobloch, Gesine; Durmus, Tahir; Hamm, Bernd [Charite - University Medicine Berlin, Department of Radiology, Berlin (Germany); Schwenke, Carsten [SCO:SSiS - Schwenke Consulting, Berlin (Germany); Huppertz, Alexander [Charite - University Medicine Berlin, Department of Radiology, Berlin (Germany); ISI - Imaging Science Institute Charite, Berlin (Germany)

2014-01-15

To assess the effect of lower volumes of contrast medium (CM) on image quality in high-pitch dual-source computed tomography coronary angiography (CTCA). One-hundred consecutive patients (body weight 65-85 kg, stable heart rate ≤65 bpm, cardiac index ≥2.5 L/min/m{sup 2}) referred for CTCA were prospectively enrolled. Patients were randomly assigned to one of five groups of different CM volumes (G{sub 30}, 30 mL; G{sub 40}, 40 mL; G{sub 50}, 50 mL; G{sub 60}, 60 mL; G{sub 70}, 70 mL; flow rate 5 mL/s each, iodine content 370 mg/mL). Attenuation within the proximal and distal coronary artery segments was analysed. Mean attenuation for men and women ranged from 345.0 and 399.1 HU in G{sub 30} to 478.2 and 571.8 HU in G{sub 70}. Mean attenuation values were higher in groups with higher CM volumes (P < 0.0001) and higher in women than in men (P < 0.0001). The proportions of segments with attenuation of at least 300 HU in G{sub 30}, G{sub 40}, G{sub 50}, G{sub 60} and G{sub 70} were 89 %, 95 %, 98 %, 98 % and 99 %. CM volume of 30 mL in women and 40 mL in men proved to be sufficient to guarantee attenuation of at least 300 HU. In selected patients high-pitch dual-source CTCA can be performed with CM volumes of 40 mL in men or 30 mL in women. (orig.)

Performance enhancement of direct ethanol fuel cell using Nafion composites with high volume fraction of titania

Science.gov (United States)

Matos, B. R.; Isidoro, R. A.; Santiago, E. I.; Fonseca, F. C.

2014-12-01

The present study reports on the performance enhancement of direct ethanol fuel cell (DEFC) at 130 °C with Nafion-titania composite electrolytes prepared by sol-gel technique and containing high volume fractions of the ceramic phase. It is found that for high volume fractions of titania (>10 vol%) the ethanol uptake of composites is largely reduced while the proton conductivity at high-temperatures is weakly dependent on the titania content. Such tradeoff between alcohol uptake and conductivity resulted in a boost of DEFC performance at high temperatures using Nafion-titania composites with high fraction of the inorganic phase.

Survival rate in nasopharyngeal carcinoma improved by high caseload volume: a nationwide population-based study in Taiwan

International Nuclear Information System (INIS)

Lee, Ching-Chih; Hung, Shih-Kai; Huang, Tze-Ta; Lee, Moon-Sing; Su, Yu-Chieh; Chou, Pesus; Hsiao, Shih-Hsuan; Chiou, Wen-Yen; Lin, Hon-Yi; Chien, Sou-Hsin

2011-01-01

Positive correlation between caseload and outcome has previously been validated for several procedures and cancer treatments. However, there is no information linking caseload and outcome of nasopharyngeal carcinoma (NPC) treatment. We used nationwide population-based data to examine the association between physician case volume and survival rates of patients with NPC. Between 1998 and 2000, a total of 1225 patients were identified from the Taiwan National Health Insurance Research Database. Survival analysis, the Cox proportional hazards model, and propensity score were used to assess the relationship between 10-year survival rates and physician caseloads. As the caseload of individual physicians increased, unadjusted 10-year survival rates increased (p < 0.001). Using a Cox proportional hazard model, patients with NPC treated by high-volume physicians (caseload ≥ 35) had better survival rates (p = 0.001) after adjusting for comorbidities, hospital, and treatment modality. When analyzed by propensity score, the adjusted 10-year survival rate differed significantly between patients treated by high-volume physicians and patients treated by low/medium-volume physicians (75% vs. 61%; p < 0.001). Our data confirm a positive volume-outcome relationship for NPC. After adjusting for differences in the case mix, our analysis found treatment of NPC by high-volume physicians improved 10-year survival rate

Volume Bragg grating narrowed high-power and highly efficient cladding-pumped Raman fiber laser.

Science.gov (United States)

Liu, Jun; Yao, Weichao; Zhao, Chujun; Shen, Deyuan; Fan, Dianyuan

2014-12-10

High-power and highly efficient operation of a single-mode cladding-pumped Raman fiber laser with narrow lasing bandwidth is demonstrated. The spectral narrowing was realized by an external cavity containing a volume Bragg grating with a center wavelength of 1658 nm. A maximum output power of 10.4 W at 1658.3 nm with a spectral linewidth (FWHM) of ∼0.1  nm was obtained for the launched pump power of 18.4 W, corresponding to a slope efficiency of 109% with respect to the launched pump power. Lasing characteristics of free-running operation are also evaluated and discussed.

Breakdown pressures and characteristic flaw sizes during fluid injection experiments in shale at elevated confining pressures.

Science.gov (United States)

Chandler, M.; Mecklenburgh, J.; Rutter, E. H.; Taylor, R.; Fauchille, A. L.; Ma, L.; Lee, P. D.

2017-12-01

Fracture propagation trajectories in gas-bearing shales depend on the interaction between the anisotropic mechanical properties of the shale and the anisotropic in-situ stress field. However, there is a general paucity of available experimental data on their anisotropic mechanical, physical and fluid-flow properties, especially at elevated confining pressures. A suite of mechanical, flow and elastic measurements have been made on two shale materials, the Whitby mudrock and the Mancos shale (an interbedded silt and mudstone), as well as Pennant sandstone, an isotropic baseline and tight-gas sandstone analogue. Mechanical characterization includes standard triaxial experiments, pressure-dependent permeability, brazilian disk tensile strength, and fracture toughness determined using double-torsion experiments. Elastic characterisation was performed through ultrasonic velocities determined using a cross-correlation method. Additionally, we report the results of laboratory-scale fluid injection experiments for the same materials. Injection experiments involved the pressurisation of a blind-ending central hole in a dry cylindrical sample. Pressurisation is conducted under constant volume-rate control, using silicon oils of varying viscosities. Breakdown pressure is not seen to exhibit a strong dependence on rock type or orientation, and increases linearly with confining pressure. In most experiments, a small drop in the injection pressure record is observed at what is taken to be fracture initiation, and in the Pennant sandstone this is accompanied by a small burst of acoustic energy. The shale materials were acoustically quiet. Breakdown is found to be rapid and uncontrollable after initiation if injection is continued. A simplified 2-dimensional model for explaining this is presented in terms of the stress intensities at the tip of a pressurised crack, and is used alongside the triaxial data to derive a characteristic flaw size from which the fractures have initiated

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

International Nuclear Information System (INIS)

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

Electrophoretically active sol-gel processes to backfill, seal, and/or densify porous, flawed, and/or cracked coatings on electrically conductive material

Science.gov (United States)

Panitz, Janda K.; Reed, Scott T.; Ashley, Carol S.; Neiser, Richard A.; Moffatt, William C.

1999-01-01

Electrophoretically active sol-gel processes to fill, seal, and/or density porous, flawed, and/or cracked coatings on electrically conductive substrates. Such coatings may be dielectrics, ceramics, or semiconductors and, by the present invention, may have deposited onto and into them sol-gel ceramic precursor compounds which are subsequently converted to sol-gel ceramics to yield composite materials with various tailored properties.

Adjustable mounting device for high-volume production of beam-shaping systems for high-power diode lasers

Science.gov (United States)

Haag, Sebastian; Bernhardt, Henning; Rübenach, Olaf; Haverkamp, Tobias; Müller, Tobias; Zontar, Daniel; Brecher, Christian

2015-02-01

In many applications for high-power diode lasers, the production of beam-shaping and homogenizing optical systems experience rising volumes and dynamical market demands. The automation of assembly processes on flexible and reconfigurable machines can contribute to a more responsive and scalable production. The paper presents a flexible mounting device designed for the challenging assembly of side-tab based optical systems. It provides design elements for precisely referencing and fixating two optical elements in a well-defined geometric relation. Side tabs are presented to the machine allowing the application of glue and a rotating mechanism allows the attachment to the optical elements. The device can be adjusted to fit different form factors and it can be used in high-volume assembly machines. The paper shows the utilization of the device for a collimation module consisting of a fast-axis and a slow-axis collimation lens. Results regarding the repeatability and process capability of bonding side tab assemblies as well as estimates from 3D simulation for overall performance indicators achieved such as cycle time and throughput will be discussed.

Security Flaws in an Efficient Pseudo-Random Number Generator for Low-Power Environments

Science.gov (United States)

Peris-Lopez, Pedro; Hernandez-Castro, Julio C.; Tapiador, Juan M. E.; Millán, Enrique San; van der Lubbe, Jan C. A.

In 2004, Settharam and Rhee tackled the design of a lightweight Pseudo-Random Number Generator (PRNG) suitable for low-power environments (e.g. sensor networks, low-cost RFID tags). First, they explicitly fixed a set of requirements for this primitive. Then, they proposed a PRNG conforming to these requirements and using a free-running timer [9]. We analyze this primitive discovering important security faults. The proposed algorithm fails to pass even relatively non-stringent batteries of randomness such as ENT (i.e. a pseudorandom number sequence test program). We prove that their recommended PRNG has a very short period due to the flawed design of its core. The internal state can be easily revealed, compromising its backward and forward security. Additionally, the rekeying algorithm is defectively designed mainly related to the unpractical value proposed for this purpose.

Is orbital volume associated with eyeball and visual cortex volume in humans?

Science.gov (United States)

Pearce, Eiluned; Bridge, Holly

2013-01-01

In humans orbital volume increases linearly with absolute latitude. Scaling across mammals between visual system components suggests that these larger orbits should translate into larger eyes and visual cortices in high latitude humans. Larger eyes at high latitudes may be required to maintain adequate visual acuity and enhance visual sensitivity under lower light levels. To test the assumption that orbital volume can accurately index eyeball and visual cortex volumes specifically in humans. Structural Magnetic Resonance Imaging (MRI) techniques are employed to measure eye and orbit (n = 88) and brain and visual cortex (n = 99) volumes in living humans. Facial dimensions and foramen magnum area (a proxy for body mass) were also measured. A significant positive linear relationship was found between (i) orbital and eyeball volumes, (ii) eyeball and visual cortex grey matter volumes and (iii) different visual cortical areas, independently of overall brain volume. In humans the components of the visual system scale from orbit to eye to visual cortex volume independently of overall brain size. These findings indicate that orbit volume can index eye and visual cortex volume in humans, suggesting that larger high latitude orbits do translate into larger visual cortices.

High Productivity DRIE solutions for 3D-SiP and MEMS Volume Manufacturing

International Nuclear Information System (INIS)

Puech, M; Thevenoud, J M; Launay, N; Arnal, N; Godinat, P; Andrieu, B; Gruffat, J M

2006-01-01

Emerging 3D-SiP technologies and high volume MEMS applications require high productivity mass production DRIE systems. The Alcatel DRIE product range has recently been optimised to reach the highest process and hardware production performances. A study based on sub-micron high aspect ratio structures encountered in the most stringent 3D-SiP has been carried out. The optimization of the Bosch process parameters has resulted in ultra high silicon etch rates, with unrivalled uniformity and repeatability leading to excellent process. In parallel, most recent hardware and proprietary design optimization including vacuum pumping lines, process chamber, wafer chucks, pressure control system, gas delivery are discussed. These improvements have been monitored in a mass production environment for a mobile phone application. Field data analysis shows a significant reduction of cost of ownership thanks to increased throughput and much lower running costs. These benefits are now available for all 3D-SiP and high volume MEMS applications. The typical etched patterns include tapered trenches for CMOS imagers, through silicon via holes for die stacking, well controlled profile angle for 3D high precision inertial sensors, and large exposed area features for inkjet printer heads and Silicon microphones

High-energy molecular lasers self-controlled volume-discharge lasers and applications

CERN Document Server

Apollonov, V V

2016-01-01

This book displays the physics and design of high-power molecular lasers. The lasers described are self-controlled volume-discharge lasers. The book explains self-sustained discharge lasers, self-initiated discharge lasers and technical approaches to laser design. Important topics discussed are laser efficiency, laser beam quality and electric field homogeneity. The book contains many new innovative applications.

77 FR 21065 - Certain High Production Volume Chemicals; Test Rule and Significant New Use Rule; Fourth Group of...

Science.gov (United States)

2012-04-09

... 2070-AJ66 Certain High Production Volume Chemicals; Test Rule and Significant New Use Rule; Fourth... an opportunity to comment on a proposed test rule for 23 high production volume (HPV) chemical... necessary, to prohibit or limit that activity before it occurs. The opportunity to present oral comment was...

Ductile growth of crack like flawing during hydrotest; Propagacao dutil de defeitos planares durante teste hidrostatico

Energy Technology Data Exchange (ETDEWEB)

Teixeira, Jose C; Donato, Guilherme V [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES); Silva, Marcinei S. da; Bastian, Fernando L [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE); Lima, Romulo S. de [PETROBRAS/AB-RE, Rio de Janeiro, RJ (Brazil)

2003-07-01

In this paper effects of hydrostatic testing on ductile propagation of crack like flaw defects were evaluated in API X-60 steel. The model used was based on the J-tearing theory, supported by elastic - plastic fracture mechanics. The J-initiation resistance values (JIc) were determined by fracture mechanic tests using potential drop technique and compact test specimen. The JIc values were also determined from flow stress and Charpy V-notch at plateau, which are both usually available in mill-test data. Despite of being based on small database it seems it could be extended and it will be useful for future analysis. (author)

Association Between Treatment at a High-Volume Facility and Improved Survival for Radiation-Treated Men With High-Risk Prostate Cancer

Energy Technology Data Exchange (ETDEWEB)

Chen, Yu-Wei [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts (United States); Mahal, Brandon A. [Department of Medicine, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Harvard Medical School, Boston, Massachusetts (United States); Muralidhar, Vinayak [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts (United States); Harvard Medical School, Boston, Massachusetts (United States); Nezolosky, Michelle [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts (United States); Beard, Clair J. [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts (United States); Harvard Medical School, Boston, Massachusetts (United States); Den, Robert B. [Department of Radiation Oncology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania (United States); Feng, Felix Y. [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Hoffman, Karen E. [Department of Radiation Oncology, the University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Martin, Neil E.; Orio, Peter F. [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts (United States); Harvard Medical School, Boston, Massachusetts (United States); Nguyen, Paul L., E-mail: pnguyen@LROC.harvard.edu [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts (United States); Harvard Medical School, Boston, Massachusetts (United States)

2016-03-15

Purpose: Although the association between higher hospital volume and improved outcomes has been well-documented in surgery, there is little data about whether this effect exists for radiation-treated patients. We investigated whether treatment at a radiation facility that treats a high volume of prostate cancer patients is associated with improved survival for men with high-risk prostate cancer. Methods and Materials: We used the National Cancer Database (NCDB) to identity patients diagnosed with prostate cancer from 2004 to 2006. The radiation case volume (RCV) of each hospital was based on its number of radiation-treated prostate cancer patients. We used propensity-score based analysis to compare the overall survival (OS) of high-risk prostate cancer patients in high versus low RCV hospitals. Primary endpoint is overall survival. Covariates adjusted for were tumor characteristics, sociodemographic factors, radiation type, and use of androgen deprivation therapy (ADT). Results: A total of 19,565 radiation-treated high-risk patients were identified. Median follow-up was 81.0 months (range: 1-108 months). When RCV was coded as a continuous variable, each increment of 100 radiation-managed patients was associated with improved OS (adjusted hazard ratio [AHR]: 0.97; 95% confidence interval [CI]: 0.95-0.98; P<.0001) after adjusting for known confounders. For illustrative purposes, when RCV was dichotomized at the 80th percentile (43 patients/year), high RCV was associated with improved OS (7-year overall survival 76% vs 74%, log-rank test P=.0005; AHR: 0.91, 95% CI: 0.86-0.96, P=.0005). This association remained significant when RCV was dichotomized at 75th (37 patients/year), 90th (60 patients/year), and 95th (84 patients/year) percentiles but not the 50th (19 patients/year). Conclusions: Our results suggest that treatment at centers with higher prostate cancer radiation case volume is associated with improved OS for radiation-treated men with high-risk prostate

Just-in-Time Training for High-Risk Low-Volume Therapies: An Approach to Ensure Patient Safety.

Science.gov (United States)

Helman, Stephanie; Lisanti, Amy Jo; Adams, Ann; Field, Cynthia; Davis, Katherine Finn

2016-01-01

High-risk low-volume therapies are those therapies that are practiced infrequently and yet carry an increased risk to patients because of their complexity. Staff nurses are required to competently manage these therapies to treat patients' unique needs and optimize outcomes; however, maintaining competence is challenging. This article describes implementation of Just-in-Time Training, which requires validation of minimum competency of bedside nurses managing high-risk low-volume therapies through direct observation of a return-demonstration competency checklist.

Automatic detection of flaws in polymer insulators using 3D industrial tomography; Deteccao automatica de vazios em isoladores polimericos por tomografia industrial 3D

Energy Technology Data Exchange (ETDEWEB)

Godoi, Walmor Cardoso; Swinka-Filho, Vitoldo [Instituto de Tecnologia para o Desenvolvimento (LACTEC), Curitiba, PR (Brazil)], Emails: walmor@lactec.org.br, vitoldo@lactec.org.br; Geus, Klaus de [Companhia Paranaense de Energia (Copel), Curitiba, PR (Brazil)], Email: klaus@copel.com; Silva, Romeu Ricardo da [SENAI-RJ Solda (CTS/Solda), Rio de Janeiro, RJ (Brazil). Centro de Tecnologia], Email: rrdsilva@firjan.org.br

2009-10-15

This work presents a methodology for the automatic detection of flaws in polymer insulators using three-dimensional industrial computed tomography (CT), as well as results obtained in the context of power distribution networks. The CT slices were reconstructed using 180 digital radiographs (projections) acquired by a high resolution system (pixel dimension of 50 {mu}m x 50 {mu}m, a-Si). For the reconstruction of 3D CT, 50 {mu}m wide bit map slices were used. The Marching Cubes algorithm was used to perform the 3D reconstruction, using the Visualization Tool kit (VTK) library and the Java programming language (64 Bits Linux platform). Nine features were obtained from the reconstructed three-dimensional objects for the neural networks training. Results showed to be satisfactory. (author)

High Center Volume Does Not Mitigate Risk Associated with Using High Donor Risk Organs in Liver Transplantation.

Science.gov (United States)

Beal, Eliza W; Black, Sylvester M; Mumtaz, Khalid; Hayes, Don; El-Hinnawi, Ashraf; Washburn, Kenneth; Tumin, Dmitry

2017-09-01

High-risk donor allografts increase access to liver transplant, but potentially reduce patient and graft survival. It is unclear whether the risk associated with using marginal donor livers is mitigated by increasing center experience. The United Network for Organ Sharing registry was queried for adult first-time liver transplant recipients between 2/2002 and 12/2015. High donor risk was defined as donor risk index >1.9, and 1-year patient and graft survival were compared according to donor risk index in small and large centers. Multivariable Cox regression estimated the hazard ratio (HR) associated with using high-risk donor organs, according to a continuous measure of annual center volume. The analysis included 51,770 patients. In 67 small and 67 large centers, high donor risk index predicted increased mortality (p = 0.001). In multivariable analysis, high-donor risk index allografts predicted greater mortality hazard at centers performing 20 liver transplants per year (HR 1.35; 95% CI 1.22, 1.49; p donor risk index and center volume was not statistically significant (p = 0.747), confirming that the risk associated with using marginal donor livers was comparable between smaller and larger centers. Results were consistent when examining graft loss. At both small and large centers, high-risk donor allografts were associated with reduced patient and graft survival after liver transplant. Specific strategies to mitigate the risk of liver transplant involving high-risk donors are needed, in addition to accumulation of center expertise.

Investigation into the use of smartphone as a machine vision device for engineering metrology and flaw detection, with focus on drilling

Science.gov (United States)

Razdan, Vikram; Bateman, Richard

2015-05-01

This study investigates the use of a Smartphone and its camera vision capabilities in Engineering metrology and flaw detection, with a view to develop a low cost alternative to Machine vision systems which are out of range for small scale manufacturers. A Smartphone has to provide a similar level of accuracy as Machine Vision devices like Smart cameras. The objective set out was to develop an App on an Android Smartphone, incorporating advanced Computer vision algorithms written in java code. The App could then be used for recording measurements of Twist Drill bits and hole geometry, and analysing the results for accuracy. A detailed literature review was carried out for in-depth study of Machine vision systems and their capabilities, including a comparison between the HTC One X Android Smartphone and the Teledyne Dalsa BOA Smart camera. A review of the existing metrology Apps in the market was also undertaken. In addition, the drilling operation was evaluated to establish key measurement parameters of a twist Drill bit, especially flank wear and diameter. The methodology covers software development of the Android App, including the use of image processing algorithms like Gaussian Blur, Sobel and Canny available from OpenCV software library, as well as designing and developing the experimental set-up for carrying out the measurements. The results obtained from the experimental set-up were analysed for geometry of Twist Drill bits and holes, including diametrical measurements and flaw detection. The results show that Smartphones like the HTC One X have the processing power and the camera capability to carry out metrological tasks, although dimensional accuracy achievable from the Smartphone App is below the level provided by Machine vision devices like Smart cameras. A Smartphone with mechanical attachments, capable of image processing and having a reasonable level of accuracy in dimensional measurement, has the potential to become a handy low-cost Machine vision

Two-ion theory of energy coupling in ATP synthesis rectifies a fundamental flaw in the governing equations of the chemiosmotic theory.

Science.gov (United States)

Nath, Sunil

2017-11-01

The vital coupled processes of oxidative phosphorylation and photosynthetic phosphorylation synthesize molecules of adenosine-5'-triphosphate (ATP), the universal biological energy currency, and sustain all life on our planet. The chemiosmotic theory of energy coupling in oxidative and photophosphorylation was proposed by Mitchell >50years ago. It has had a contentious history, with part of the accumulated body of experimental evidence supporting it, and part of it in conflict with the theory. Although the theory was strongly criticized by many prominent scientists, the controversy has never been resolved. Here, the mathematical steps of Mitchell's original derivation leading to the principal equation of the chemiosmotic theory are scrutinized, and a fundamental flaw in them has been identified. Surprisingly, this flaw had not been detected earlier. Discovery of such a defect negates, or at least considerably weakens, the theoretical foundations on which the chemiosmotic theory is based. Ad hoc or simplistic ways to remedy this defect are shown to be scientifically unproductive and sterile. A novel two-ion theory of biological energy coupling salvages the situation by rectifying the fundamental flaw in the chemiosmotic theory, and the governing equations of the new theory have been shown to accurately quantify and predict extensive recent experimental data on ATP synthesis by F 1 F O -ATP synthase without using adjustable parameters. Some major biological implications arising from the new thinking are discussed. The principles of energy transduction and coupling proposed in the new paradigm are shown to be of a very general and universal nature. It is concluded that the timely availability after a 25-year research struggle of Nath's torsional mechanism of energy transduction and ATP synthesis is a rational alternative that has the power to solve the problems arising from the past, and also meet present and future challenges in this important interdisciplinary field

A study on the effect of flaw detection probability assumptions on risk reduction achieved by non-destructive inspection

International Nuclear Information System (INIS)

Cronvall, O.; Simola, K.; Männistö, I.; Gunnars, J.; Alverlind, L.; Dillström, P.; Gandossi, L.

2012-01-01

Leakages and ruptures of piping components lead to reduction or loss of the pressure retaining capability of the system, and thus contribute to the overall risk associated with nuclear power plants. In-service inspection (ISI) aims at verifying that defects are not present in components of the pressure boundary or, if defects are present, ensuring that these are detected before they affect the safe operation of the plant. Reliability estimates of piping are needed e.g., in probabilistic safety assessment (PSA) studies, risk-informed ISI (RI-ISI) applications, and other structural reliability assessments. Probabilistic fracture mechanics models can account for ISI reliability, but a quantitative estimate for the latter is needed. This is normally expressed in terms of probability of detection (POD) curves, which correlate the probability of detecting a flaw with flaw size. A detailed POD curve is often difficult (or practically impossible) to obtain. If sufficient risk reduction can be shown by using simplified (but reasonably conservative) POD estimates, more complex PODs are not needed. This paper summarises the results of a study on the effect of piping inspection reliability assumptions on failure probability using structural reliability models. The main interest was to investigate whether it is justifiable to use a simplified POD curve. Further, the study compared various structural reliability calculation approaches for a set of analysis cases. The results indicate that the use of a simplified POD could be justifiable in RI-ISI applications.

VOLUME STUDY WITH HIGH DENSITY OF PARTICLES BASED ON CONTOUR AND CORRELATION IMAGE ANALYSIS

Directory of Open Access Journals (Sweden)

Tatyana Yu. Nikolaeva

2014-11-01

Full Text Available The subject of study is the techniques of particle statistics evaluation, in particular, processing methods of particle images obtained by coherent illumination. This paper considers the problem of recognition and statistical accounting for individual images of small scattering particles in an arbitrary section of the volume in case of high concentrations. For automatic recognition of focused particles images, a special algorithm for statistical analysis based on contouring and thresholding was used. By means of the mathematical formalism of the scalar diffraction theory, coherent images of the particles formed by the optical system with high numerical aperture were simulated. Numerical testing of the method proposed for the cases of different concentrations and distributions of particles in the volume was performed. As a result, distributions of density and mass fraction of the particles were obtained, and the efficiency of the method in case of different concentrations of particles was evaluated. At high concentrations, the effect of coherent superposition of the particles from the adjacent planes strengthens, which makes it difficult to recognize images of particles using the algorithm considered in the paper. In this case, we propose to supplement the method with calculating the cross-correlation function of particle images from adjacent segments of the volume, and evaluating the ratio between the height of the correlation peak and the height of the function pedestal in the case of different distribution characters. The method of statistical accounting of particles considered in this paper is of practical importance in the study of volume with particles of different nature, for example, in problems of biology and oceanography. Effective work in the regime of high concentrations expands the limits of applicability of these methods for practically important cases and helps to optimize determination time of the distribution character and

High-level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 4

Energy Technology Data Exchange (ETDEWEB)

1994-04-01

The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Identification Document (S/RID) is contained in multiple volumes. This document (Volume 4) presents the standards and requirements for the following sections: Radiation Protection and Operations.

High-level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 4

International Nuclear Information System (INIS)

1994-04-01

The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Identification Document (S/RID) is contained in multiple volumes. This document (Volume 4) presents the standards and requirements for the following sections: Radiation Protection and Operations

Identification of Flaws Responsible for Crack Initiation and Micromechanisms of Slow Crack Growth in the Delayed Fracture of Alumina.

Science.gov (United States)

1982-02-01

A-"AIS012 CALIFORNIA UNdIV LOS ANSELES DEPT OF MATERIALS SCIEN--ETC F/S 11/6 IDENTIFICATION OF FLAWS RESPONSIBLE FOR CRACK INITIATION AM %I--ETC(U...Sines and Adams . 71 It might be thought that other compressive loading devices could serve the same purpoee. For example, a spherical joint instead of the...compressive strength can be 18 times the tensile strength as reported by Adams . 92 This is because the established criteria are damage criter- ia, not

Laboratory Investigations on Mechanical Properties of High Volume Fly Ash Concrete and Composite Sections

OpenAIRE

Aravindkumar B. Harwalkar; S. S. Awanti

2013-01-01

Use of fly ash as a supplementary cementing material in large volumes can bring both technological and economic benefits for concrete industry. In this investigation mix proportions for high volume fly ash concrete were determined at cement replacement levels of 50%, 55%, 60% and 65% with low calcium fly ash. Flexural and compressive strengths of different mixes were measured at ages of 7, 28 and 90 days. Flexural strength of composite section prepared from pavement quali...

High-level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 5

International Nuclear Information System (INIS)

1994-04-01

The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Identification Document (S/RID) is contained in multiple volumes. This document (Volume 5) outlines the standards and requirements for the Fire Protection and Packaging and Transportation sections

Fracture criterion for brittle materials based on statistical cells of finite volume

International Nuclear Information System (INIS)

Cords, H.; Kleist, G.; Zimmermann, R.

1986-06-01

An analytical consideration of the Weibull Statistical Analysis of brittle materials established the necessity of including one additional material constant for a more comprehensive description of the failure behaviour. The Weibull analysis is restricted to infinitesimal volume elements in consequence of the differential calculus applied. It was found that infinitesimally small elements are in conflict with the basic statistical assumption and that the differential calculus is not needed in fact since nowadays most of the stress analyses are based on finite element calculations, and these are most suitable for a subsequent statistical analysis of strength. The size of a finite statistical cell has been introduced as the third material parameter. It should represent the minimum volume containing all statistical features of the material such as distribution of pores, flaws and grains. The new approach also contains a unique treatment of failure under multiaxial stresses. The quantity responsible for failure under multiaxial stresses is introduced as a modified strain energy. Sixteen different tensile specimens including CT-specimens have been investigated experimentally and analyzed with the probabilistic fracture criterion. As a result it can be stated that the failure rates of all types of specimens made from three different grades of graphite are predictable. The accuracy of the prediction is one standard deviation. (orig.) [de

EUV mask defect inspection and defect review strategies for EUV pilot line and high volume manufacturing

Science.gov (United States)

Chan, Y. David; Rastegar, Abbas; Yun, Henry; Putna, E. Steve; Wurm, Stefan

2010-04-01

Reducing mask blank and patterned mask defects is the number one challenge for extreme ultraviolet lithography. If the industry succeeds in reducing mask blank defects at the required rate of 10X every year for the next 2-3 years to meet high volume manufacturing defect requirements, new inspection and review tool capabilities will soon be needed to support this goal. This paper outlines the defect inspection and review tool technical requirements and suggests development plans to achieve pilot line readiness in 2011/12 and high volume manufacturing readiness in 2013. The technical specifications, tooling scenarios, and development plans were produced by a SEMATECH-led technical working group with broad industry participation from material suppliers, tool suppliers, mask houses, integrated device manufacturers, and consortia. The paper summarizes this technical working group's assessment of existing blank and mask inspection/review infrastructure capabilities to support pilot line introduction and outlines infrastructure development requirements and tooling strategies to support high volume manufacturing.

Mechanized radiation testing of austenitic pipe welds. Testing of media filled pipes and determination of the flaw depth by tomosynthesis; Mechanisierte Durchstrahlungspruefung von Rundschweissnaehten. Pruefung mediengefuellter Rohrleitungen und Tiefenlagenbestimmung durch Tomosynthese

Energy Technology Data Exchange (ETDEWEB)

Ewert, U.; Redmer, B. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany); Mueller, J. [COMPRA GmbH, Frechen (Germany); Trobitz, M. [Kernkraftwerke Gundremmingen Betriebsgesellschaft mbH, Gundremmingen (Germany); Baranov, V.A. [Institute for Introscopy, Tomsk (Russian Federation)

1999-08-01

A compact detection system was built for multi-angle inspection of pipes, consisting of a high-sensitivity radiometric line scanner and an ultrasonic manipulator. Improved flaw imaging quality is achieved with this system as compared to film radiography. Measurements have been carried out on site in a nuclear power plant and in a laboratory. Better flaw imaging quality was also achieved in the testing of water-filled pipes. Non-linear tomosynthesis was applied for processing and interpretation of measured data. The system delivers considerably better images of planary materials inhomogeneitites, (such as cracks and lack-of-bond defects). (orig./CB) [Deutsch] Eine hoch empfindliche radiometrische Zeilenkamera wurde mit einem Ultraschall-Manipulator zu einem Gesamtsystem aufgebaut und fuer Mehrwinkel-Inspektionen von Rohrleitungen angewandt. Bei der Inspektion von Rundschweissnaehten an Rohren mit ca. 8... 20 mm Wanddicke wurde eine Verbesserung der Bildqualitaet im Vergleich zur Filmradiographie erreicht. Diese Messungen wurden in einem Kernkraftwerk unter Vor-Ort-Bedingungen sowie im Labor ausgefuehrt. Ein signifikantes Ansteigen der Bildqualitaet wurde auch bei der Pruefung von wassergefuellten Rohren erzielt. Methoden der nicht-linearen Tomosynthese wurden fuer die Verarbeitung und Interpretation der gemessenen Projektionsdaten genutzt. Das entwickelte System gestattet eine erhebliche Verbesserung der Anzeige von planaren Materialinhomogenitaeten (z.B. Risse und Bindefehler). (orig./DGE)

Distributed system for parallel data processing of ECT signals for electromagnetic flaw detection in materials

International Nuclear Information System (INIS)

Guliashki, Vassil; Marinova, Galia

2002-01-01

The paper proposes a distributed system for parallel data processing of ECT signals for flaw detection in materials. The measured data are stored in files on a host computer, where a JAVA server is located. The host computer is connected through Internet to a set of client computers, distributed geographically. The data are distributed from the host computer by means of the JAVA server to the client computers according their requests. The software necessary for the data processing is installed on each client computer in advance. The organization of the data processing on many computers, working simultaneously in parallel, leads to great time reducing, especially in cases when huge amount of data should be processed in very short time. (Author)

Proceedings of the 1984 workshop on high-energy excitations in condensed matter. Volume II

International Nuclear Information System (INIS)

Silver, R.N.

1984-12-01

This volume covers electronic excitations, momentum distributions, high energy photons, and a wrap-up session. Abstracts of individual items from the conference were prepared separately for the data base

Scoping studies to reduce ICPP high-level radioactive waste volumes for final disposal

International Nuclear Information System (INIS)

Knecht, D.A.; Berreth, J.R.; Chipman, N.A.; Cole, H.S.; Geczi, L.S.; Kerr, W.B.; Staples, B.A.

1985-08-01

This report presents the results of scoping studies carried out to determine the feasibility of the following candidate options to reduce high-level waste volume: (1) low-fluoride, low-volume glass, (2) glass-ceramic and ceramic, (3) Modified Zirflex, (4) inerts removal by neutralization, and (5) modified Fluorinel processes. The results of the scoping studies show that the glass-ceramic/ceramic waste forms and neutralization process with potential HLW volume reductions ranging from 60 to 80% appear feasible, based on laboratory-scale tests. The presently used Fluorinel process modified by reducing HF usage also appears to be feasible and could result in up to a 10% potential volume reduction. If the current process start-up tests verify the practicality, reduced HF usage will be implemented. The low-volume glass and Modified Zirflex processes may also be feasible, based on laboratory tests, but would require significantly more process development and/or modifications and could result in only a 20 to 30% potential volume reduction. Based on these scoping studies, it is recommended that (1) the glass-ceramic/ceramic and neutralization processes be developed further, (2) reduced HF use for the Modified Fluorinel process be implemented as soon as practical and other options reducing chemical usage for criticality control be evaluated, (3) basic development for the glass process be continued as a back-up technology, and (4) laboratory-scale radioactive fuel dissolution testing for the Modified Zirflex process be completed with further process development discontinued unless needed in the future

Flaws in current human training protocols for spontaneous Brain-Computer Interfaces: lessons learned from instructional design

Directory of Open Access Journals (Sweden)

Fabien eLotte

2013-09-01

Full Text Available While recent research on Brain-Computer Interfaces (BCI has highlighted their potential for many applications, they remain barely used outside laboratories. The main reason is their lack of robustness. Indeed, with current BCI, mental state recognition is usually slow and often incorrect. Spontaneous BCI (i.e., mental imagery-based BCI often rely on mutual learning efforts by the user and the machine, with BCI users learning to produce stable EEG patterns (spontaneous BCI control being widely acknowledged as a skill while the computer learns to automatically recognize these EEG patterns, using signal processing. Most research so far was focused on signal processing, mostly neglecting the human in the loop. However, how well the user masters the BCI skill is also a key element explaining BCI robustness. Indeed, if the user is not able to produce stable and distinct EEG patterns, then no signal processing algorithm would be able to recognize them. Unfortunately, despite the importance of BCI training protocols, they have been scarcely studied so far, and used mostly unchanged for years.In this paper, we advocate that current human training approaches for spontaneous BCI are most likely inappropriate. We notably study instructional design literature in order to identify the key requirements and guidelines for a successful training procedure that promotes a good and efficient skill learning. This literature study highlights that current spontaneous BCI user training procedures satisfy very few of these requirements and hence are likely to be suboptimal. We therefore identify the flaws in BCI training protocols according to instructional design principles, at several levels: in the instructions provided to the user, in the tasks he/she has to perform, and in the feedback provided. For each level, we propose new research directions that are theoretically expected to address some of these flaws and to help users learn the BCI skill more efficiently.

Best Practices During Hip Arthroscopy: Aggregate Recommendations of High-Volume Surgeons.

Science.gov (United States)

Gupta, Asheesh; Suarez-Ahedo, Carlos; Redmond, John M; Gerhardt, Michael B; Hanypsiak, Bryan; Stake, Christine E; Finch, Nathan A; Domb, Benjamin G

2015-09-01

To survey surgeons who perform a high volume of hip arthroscopy procedures regarding their operative technique, type of procedure, and postoperative management. We conducted a cross-sectional survey of 27 high-volume orthopaedic surgeons specializing in hip arthroscopy to report their preferences and practices related to their operative practice and postoperative rehabilitation protocol. All participants completed the survey in person in an anonymous fashion during a meeting of the American Hip Institute. All surgeons perform hip arthroscopy with the patient in the supine position, accessing the central compartment of the hip initially, using intraoperative fluoroscopy. All surgeons perform labral repair (100%), with the majority performing labral reconstructions (77.8%) and gluteus medius repairs (81.5%). There is variability in the type of anchors used during labral repair. Most surgeons perform capsular closure in most cases (88.9%), inject either intra-articular cortisone or platelet-rich plasma at the conclusion of the procedure (59%), and prescribe a postoperative hip brace for some or all patients (59%). There is considerable variability in rehabilitation protocols. All surgeons routinely prescribe postoperative heterotopic ossification prophylaxis to their patients, with most surgeons (88.9%) prescribing a nonsteroidal anti-inflammatory medication for 3 weeks. Forty percent of the respondents use the modified Harris Hip Score as the most important outcome measure. Consistent practices such as use of intraoperative fluoroscopy, heterotopic ossification prophylaxis, and labral repair skills were identified by surveying 27 hip arthroscopy surgeons at high-volume centers. Most of the surgeons performed routine capsular closure unless underlying conditions precluded capsular release or plication. The survey identified higher variability between surgeons regarding postoperative rehabilitation protocols and use of intra-articular pharmacologic injections at the

Understanding the True Stimulated Reservoir Volume in Shale Reservoirs

KAUST Repository

Hussain, Maaruf

2017-06-06

Successful exploitation of shale reservoirs largely depends on the effectiveness of hydraulic fracturing stimulation program. Favorable results have been attributed to intersection and reactivation of pre-existing fractures by hydraulically-induced fractures that connect the wellbore to a larger fracture surface area within the reservoir rock volume. Thus, accurate estimation of the stimulated reservoir volume (SRV) becomes critical for the reservoir performance simulation and production analysis. Micro-seismic events (MS) have been commonly used as a proxy to map out the SRV geometry, which could be erroneous because not all MS events are related to hydraulic fracture propagation. The case studies discussed here utilized a fully 3-D simulation approach to estimate the SRV. The simulation approach presented in this paper takes into account the real-time changes in the reservoir\\'s geomechanics as a function of fluid pressures. It is consisted of four separate coupled modules: geomechanics, hydrodynamics, a geomechanical joint model for interfacial resolution, and an adaptive re-meshing. Reservoir stress condition, rock mechanical properties, and injected fluid pressure dictate how fracture elements could open or slide. Critical stress intensity factor was used as a fracture criterion governing the generation of new fractures or propagation of existing fractures and their directions. Our simulations were run on a Cray XC-40 HPC system. The studies outcomes proved the approach of using MS data as a proxy for SRV to be significantly flawed. Many of the observed stimulated natural fractures are stress related and very few that are closer to the injection field are connected. The situation is worsened in a highly laminated shale reservoir as the hydraulic fracture propagation is significantly hampered. High contrast in the in-situ stresses related strike-slip developed thereby shortens the extent of SRV. However, far field nature fractures that were not connected to

Communications Strategies on Alcohol and Highway Safety. Volume II. High School Youth. Final Report.

Science.gov (United States)

Grey Advertising, Inc., New York, NY.

The second part of a two-part, two volume study deals with high school youth and identifies target populations and communications strategies for encouraging personal action steps to prevent drunk driving. Data, collected from interviews and questionnaires, are summarized and presented in tabular form. One fourth of high schoolers in a…

High quality actively cooled plasma-facing components for fusion

International Nuclear Information System (INIS)

Nygren, R.E.

1995-01-01

This paper interweaves some suggestions for developing actively cooled plasma-facing components (PFCs) for future fusion devices, with supporting examples taken from the design, fabrication and operation of Tore Supra's Phase III outboard pump limiter (OPL). This actively cooled midplane limiter, designed for heat and particle removal during long-pulse operation, has been operated under essentially thermally steady state conditions. Testing to identify braze flaws, analysis of the impact of joining flaws on the thermal-hydraulic performance of the OPL, and the extensive calorimetry and IR thermography used to confirm and update safe operating limits for power handling of the OPL are reviewed. This experience suggests that, for PFCs in future fusion devices, flaw-tolerant designs are possible; analyses of the impacts of flaws on performance can provide criteria for quality assurance; and validating appropriate methods of inspection for such flaws early in the design development of PFCs is prudent. The need for in-service monitoring is also discussed. (orig.)

High-level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 2

International Nuclear Information System (INIS)

1994-04-01

The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Document (S/RID) is contained in multiple volumes. This document (Volume 2) presents the standards and requirements for the following sections: Quality Assurance, Training and Qualification, Emergency Planning and Preparedness, and Construction

High-level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 2

Energy Technology Data Exchange (ETDEWEB)

1994-04-01

The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Document (S/RID) is contained in multiple volumes. This document (Volume 2) presents the standards and requirements for the following sections: Quality Assurance, Training and Qualification, Emergency Planning and Preparedness, and Construction.

Porosity of Self-Compacting Concrete (SCC) incorporating high volume fly ash

Science.gov (United States)

Kristiawan, S. A.; Sunarmasto; Murti, G. Y.

2017-02-01

Degradation of concrete could be triggered by the presence of aggressive agents from the environment into the body of concrete. The penetration of these agents is influenced by the pore characteristics of the concrete. Incorporating a pozzolanic material such as fly ash could modify the pore characteristic of the concrete. This research aims to investigate the influence of incorporating fly ash at high volume level on the porosity of Self-Compacting Concrete (SCC). Laboratory investigations were carried out following the ASTM C642 for measuring density and volume of permeable pores (voids) of the SCC with varying fly ash contents (50-70% by weight of total binder). In addition, a measurement of permeable voids by saturation method was carried out to obtain an additional volume of voids that could not be measured by the immersion and boiling method of ASTM C642. The results show that the influence of fly ash content on the porosity appears to be dependent on age of SCC. At age less than 56 d, fly ash tends to cause an increase of voids but at 90 d of age it reduces the pores. The additional pores that can be penetrated by vacuum saturation method counts about 50% of the total voids.

Toward Smart Aerospace Structures: Design of a Piezoelectric Sensor and Its Analog Interface for Flaw Detection

Science.gov (United States)

Boukabache, Hamza; Escriba, Christophe; Fourniols, Jean-Yves

2014-01-01

Structural health monitoring using noninvasive methods is one of the major challenges that aerospace manufacturers face in this decade. Our work in this field focuses on the development and the system integration of millimetric piezoelectric sensors/ actuators to generate and measure specific guided waves. The aim of the application is to detect mechanical flaws on complex composite and alloy structures to quantify efficiently the global structures' reliability. The study begins by a physical and analytical analysis of a piezoelectric patch. To preserve the structure's integrity, the transducers are directly pasted onto the surface which leads to a critical issue concerning the interfacing layer. In order to improve the reliability and mitigate the influence of the interfacing layer, the global equations of piezoelectricity are coupled with a load transfer model. Thus we can determine precisely the shear strain developed on the surface of the structure. To exploit the generated signal, a high precision analog charge amplifier coupled to a double T notch filter were designed and scaled. Finally, a novel joined time-frequency analysis based on a wavelet decomposition algorithm is used to extract relevant structures signatures. Finally, this paper provides examples of application on aircraft structure specimens and the feasibility of the system is thus demonstrated. PMID:25365457

Toward smart aerospace structures: design of a piezoelectric sensor and its analog interface for flaw detection.

Science.gov (United States)

Boukabache, Hamza; Escriba, Christophe; Fourniols, Jean-Yves

2014-10-31

Structural health monitoring using noninvasive methods is one of the major challenges that aerospace manufacturers face in this decade. Our work in this field focuses on the development and the system integration of millimetric piezoelectric sensors/ actuators to generate and measure specific guided waves. The aim of the application is to detect mechanical flaws on complex composite and alloy structures to quantify efficiently the global structures' reliability. The study begins by a physical and analytical analysis of a piezoelectric patch. To preserve the structure's integrity, the transducers are directly pasted onto the surface which leads to a critical issue concerning the interfacing layer. In order to improve the reliability and mitigate the influence of the interfacing layer, the global equations of piezoelectricity are coupled with a load transfer model. Thus we can determine precisely the shear strain developed on the surface of the structure. To exploit the generated signal, a high precision analog charge amplifier coupled to a double T notch filter were designed and scaled. Finally, a novel joined time-frequency analysis based on a wavelet decomposition algorithm is used to extract relevant structures signatures. Finally, this paper provides examples of application on aircraft structure specimens and the feasibility of the system is thus demonstrated.

Toward Smart Aerospace Structures: Design of a Piezoelectric Sensor and Its Analog Interface for Flaw Detection

Directory of Open Access Journals (Sweden)

Hamza Boukabache

2014-10-01

Full Text Available Structural health monitoring using noninvasive methods is one of the major challenges that aerospace manufacturers face in this decade. Our work in this field focuses on the development and the system integration of millimetric piezoelectric sensors/ actuators to generate and measure specific guided waves. The aim of the application is to detect mechanical flaws on complex composite and alloy structures to quantify efficiently the global structures’ reliability. The study begins by a physical and analytical analysis of a piezoelectric patch. To preserve the structure’s integrity, the transducers are directly pasted onto the surface which leads to a critical issue concerning the interfacing layer. In order to improve the reliability and mitigate the influence of the interfacing layer, the global equations of piezoelectricity are coupled with a load transfer model. Thus we can determine precisely the shear strain developed on the surface of the structure. To exploit the generated signal, a high precision analog charge amplifier coupled to a double T notch filter were designed and scaled. Finally, a novel joined time-frequency analysis based on a wavelet decomposition algorithm is used to extract relevant structures signatures. Finally, this paper provides examples of application on aircraft structure specimens and the feasibility of the system is thus demonstrated.

Reachable volume RRT

KAUST Repository

McMahon, Troy

2015-05-01

© 2015 IEEE. Reachable volumes are a new technique that allows one to efficiently restrict sampling to feasible/reachable regions of the planning space even for high degree of freedom and highly constrained problems. However, they have so far only been applied to graph-based sampling-based planners. In this paper we develop the methodology to apply reachable volumes to tree-based planners such as Rapidly-Exploring Random Trees (RRTs). In particular, we propose a reachable volume RRT called RVRRT that can solve high degree of freedom problems and problems with constraints. To do so, we develop a reachable volume stepping function, a reachable volume expand function, and a distance metric based on these operations. We also present a reachable volume local planner to ensure that local paths satisfy constraints for methods such as PRMs. We show experimentally that RVRRTs can solve constrained problems with as many as 64 degrees of freedom and unconstrained problems with as many as 134 degrees of freedom. RVRRTs can solve problems more efficiently than existing methods, requiring fewer nodes and collision detection calls. We also show that it is capable of solving difficult problems that existing methods cannot.

Reachable volume RRT

KAUST Repository

McMahon, Troy; Thomas, Shawna; Amato, Nancy M.

2015-01-01

© 2015 IEEE. Reachable volumes are a new technique that allows one to efficiently restrict sampling to feasible/reachable regions of the planning space even for high degree of freedom and highly constrained problems. However, they have so far only been applied to graph-based sampling-based planners. In this paper we develop the methodology to apply reachable volumes to tree-based planners such as Rapidly-Exploring Random Trees (RRTs). In particular, we propose a reachable volume RRT called RVRRT that can solve high degree of freedom problems and problems with constraints. To do so, we develop a reachable volume stepping function, a reachable volume expand function, and a distance metric based on these operations. We also present a reachable volume local planner to ensure that local paths satisfy constraints for methods such as PRMs. We show experimentally that RVRRTs can solve constrained problems with as many as 64 degrees of freedom and unconstrained problems with as many as 134 degrees of freedom. RVRRTs can solve problems more efficiently than existing methods, requiring fewer nodes and collision detection calls. We also show that it is capable of solving difficult problems that existing methods cannot.

Effect of High-Temperature Curing Methods on the Compressive Strength Development of Concrete Containing High Volumes of Ground Granulated Blast-Furnace Slag

Directory of Open Access Journals (Sweden)

Wonsuk Jung

2017-01-01

Full Text Available This paper investigates the effect of the high-temperature curing methods on the compressive strength of concrete containing high volumes of ground granulated blast-furnace slag (GGBS. GGBS was used to replace Portland cement at a replacement ratio of 60% by binder mass. The high-temperature curing parameters used in this study were the delay period, temperature rise, peak temperature (PT, peak period, and temperature down. Test results demonstrate that the compressive strength of the samples with PTs of 65°C and 75°C was about 88% higher than that of the samples with a PT of 55°C after 1 day. According to this investigation, there might be optimum high-temperature curing conditions for preparing a concrete containing high volumes of GGBS, and incorporating GGBS into precast concrete mixes can be a very effective tool in increasing the applicability of this by-product.

Development of a 3-D model for eddy current testing: application for fastened structures in aeronautics

International Nuclear Information System (INIS)

Paillard, S.

2007-12-01

One of the Eddy Current Testing issues in aeronautics is the inspection of fastened structures to detect flaws nearby rivets which can grow because of mechanical stress. EADS and the CEA LIST have started a collaborative work with the support of the Ile-de-France Region to develop a simulation tool of EC fastened structures testing, integrated to the CIVA platform, aimed at conceiving testing methods, optimizing and qualifying it. The volume integral method using the Green dyadics formalism has been chosen in order to get a fast resolution of Maxwell equations. A first milestone was to build a simulation model of multilayer structures testing, thanks to the use of the multilayer Green dyads. Because of the rivet volume, 60 times bigger than the one of a typical flaw, a large number of discretization cells are needed. Therefore an iterative method has been developed in order to numerically solve large calculation zones. Finally, the flaw response simulation mostly has to cope with a scale issue between the size of the rivet and the one of the flaw, the latter being much smaller in a direction than the former. The whole model has been experimentally validated and compared to other simulation models at the important development steps: multilayer configuration, iteration resolution, and flaw signature. (author)

Development of a 3-D model for eddy current testing: application for fastened structures in aeronautics; Developpement d'un modele pour le controle non destructif par courants de Foucault de structures rivetees en aeronautique

Energy Technology Data Exchange (ETDEWEB)

Paillard, S

2007-12-15

One of the Eddy Current Testing issues in aeronautics is the inspection of fastened structures to detect flaws nearby rivets which can grow because of mechanical stress. EADS and the CEA LIST have started a collaborative work with the support of the Ile-de-France Region to develop a simulation tool of EC fastened structures testing, integrated to the CIVA platform, aimed at conceiving testing methods, optimizing and qualifying it. The volume integral method using the Green dyadics formalism has been chosen in order to get a fast resolution of Maxwell equations. A first milestone was to build a simulation model of multilayer structures testing, thanks to the use of the multilayer Green dyads. Because of the rivet volume, 60 times bigger than the one of a typical flaw, a large number of discretization cells are needed. Therefore an iterative method has been developed in order to numerically solve large calculation zones. Finally, the flaw response simulation mostly has to cope with a scale issue between the size of the rivet and the one of the flaw, the latter being much smaller in a direction than the former. The whole model has been experimentally validated and compared to other simulation models at the important development steps: multilayer configuration, iteration resolution, and flaw signature. (author)

Survival rate in nasopharyngeal carcinoma improved by high caseload volume: a nationwide population-based study in Taiwan

Directory of Open Access Journals (Sweden)

Chou Pesus

2011-08-01

Full Text Available Abstract Background Positive correlation between caseload and outcome has previously been validated for several procedures and cancer treatments. However, there is no information linking caseload and outcome of nasopharyngeal carcinoma (NPC treatment. We used nationwide population-based data to examine the association between physician case volume and survival rates of patients with NPC. Methods Between 1998 and 2000, a total of 1225 patients were identified from the Taiwan National Health Insurance Research Database. Survival analysis, the Cox proportional hazards model, and propensity score were used to assess the relationship between 10-year survival rates and physician caseloads. Results As the caseload of individual physicians increased, unadjusted 10-year survival rates increased (p p = 0.001 after adjusting for comorbidities, hospital, and treatment modality. When analyzed by propensity score, the adjusted 10-year survival rate differed significantly between patients treated by high-volume physicians and patients treated by low/medium-volume physicians (75% vs. 61%; p Conclusions Our data confirm a positive volume-outcome relationship for NPC. After adjusting for differences in the case mix, our analysis found treatment of NPC by high-volume physicians improved 10-year survival rate.

Statistical evaluation of the mechanical properties of high-volume class F fly ash concretes

KAUST Repository

Yoon, Seyoon

2014-03-01

High-Volume Fly Ash (HVFA) concretes are seen by many as a feasible solution for sustainable, low embodied carbon construction. At the moment, fly ash is classified as a waste by-product, primarily of thermal power stations. In this paper the authors experimentally and statistically investigated the effects of mix-design factors on the mechanical properties of high-volume class F fly ash concretes. A total of 240 and 32 samples were produced and tested in the laboratory to measure compressive strength and Young\\'s modulus respectively. Applicability of the CEB-FIP (Comite Euro-international du Béton - Fédération Internationale de la Précontrainte) and ACI (American Concrete Institute) Building Model Code (Thomas, 2010; ACI Committee 209, 1982) [1,2] to the experimentally-derived mechanical property data for HVFA concretes was established. Furthermore, using multiple linear regression analysis, Mean Squared Residuals (MSRs) were obtained to determine whether a weight- or volume-based mix proportion is better to predict the mechanical properties of HVFA concrete. The significance levels of the design factors, which indicate how significantly the factors affect the HVFA concrete\\'s mechanical properties, were determined using analysis of variance (ANOVA) tests. The results show that a weight-based mix proportion is a slightly better predictor of mechanical properties than volume-based one. The significance level of fly ash substitution rate was higher than that of w/b ratio initially but reduced over time. © 2014 Elsevier Ltd. All rights reserved.

High initial tidal volumes in emergency department patients at risk for acute respiratory distress syndrome.

Science.gov (United States)

Allison, Michael G; Scott, Michael C; Hu, Kami M; Witting, Michael D; Winters, Michael E

2015-04-01

Emergency department (ED) patients are at high risk for the acute respiratory distress syndrome (ARDS). Settings only 1 mL/kg above recommended tidal volumes confers harm for these patients. The purpose of this study was to determine whether ED physicians routinely initiate mechanical ventilation with low tidal volumes in patients at risk for ARDS. We retrospectively reviewed the charts of all adult patients who were intubated in an urban, academic ED. The charts were analyzed to identify patients in whom ARDS developed within 48 hours after ED admission. Patients were eligible for inclusion if they had bilateral infiltrates on imaging, had a Pao2/Fio2 ratio less than 300 mm Hg and did not have heart failure contributing to their presentation. The tidal volumes set in the ED were then compared with the recommended tidal volume of 6 mL/kg of predicted body weight. The initial tidal volumes set in the ED were higher than recommended by an average of 80 mL (95% confidence interval, 60-110, P tidal volume ventilation setting. In an academic, tertiary hospital, newly intubated ED patients in whom ARDS developed within 48 hours after intubation were ventilated with tidal volumes that exceeded recommendations by an average of 1.5 mL/kg. Copyright © 2014 Elsevier Inc. All rights reserved.

High level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 6

Energy Technology Data Exchange (ETDEWEB)

1994-04-01

The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Identification Document (S/RID) is contained in multiple volumes. This document (Volume 6) outlines the standards and requirements for the sections on: Environmental Restoration and Waste Management, Research and Development and Experimental Activities, and Nuclear Safety.

High level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 6

International Nuclear Information System (INIS)

1994-04-01

The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Identification Document (S/RID) is contained in multiple volumes. This document (Volume 6) outlines the standards and requirements for the sections on: Environmental Restoration and Waste Management, Research and Development and Experimental Activities, and Nuclear Safety

Dose volume assessment of high dose rate 192IR endobronchial implants

International Nuclear Information System (INIS)

Cheng, B. Saw; Korb, Leroy J.; Pawlicki, Todd; Wu, Andrew

1996-01-01

Purpose: To study the dose distributions of high dose rate (HDR) endobronchial implants using the dose nonuniformity ratio (DNR) and three volumetric irradiation indices. Methods and Materials: Multiple implants were configured by allowing a single HDR 192 Ir source to step through a length of 6 cm along an endobronchial catheter. Dwell times were computed to deliver a dose of 5 Gy to points 1 cm away from the catheter axis. Five sets of source configurations, each with different dwell position spacings from 0.5 to 3.0 cm, were evaluated. Three-dimensional (3D) dose distributions were then generated for each source configuration. Differential and cumulative dose-volume curves were generated to quantify the degree of target volume coverage, dose nonuniformity within the target volume, and irradiation of tissues outside the target volume. Evaluation of the implants were made using the DNR and three volumetric irradiation indices. Results: The observed isodose distributions were not able to satisfy all the dose constraints. The ability to optimally satisfy the dose constraints depended on the choice of dwell position spacing and the specification of the dose constraint points. The DNR and irradiation indices suggest that small dwell position spacing does not result in a more homogeneous dose distribution for the implant. This study supports the existence of a relationship between the dwell position spacing and the distance from the catheter axis to the reference dose or dose constraint points. Better dose homogeneity for an implant can be obtained if the spacing of the dwell positions are about twice the distance from the catheter axis to the reference dose or dose constraint points

A Study on the Evaluation of Field Application of High-Fluidity Concrete Containing High Volume Fly Ash

Directory of Open Access Journals (Sweden)

Yun-Wang Choi

2015-01-01

Full Text Available In the recent concrete industry, high-fluidity concrete is being widely used for the pouring of dense reinforced concrete. Normally, in the case of high-fluidity concrete, it includes high binder contents, so it is necessary to replace part of the cement through admixtures such as fly ash to procure economic feasibility and durability. This study shows the mechanical properties and field applicability of high-fluidity concrete using mass of fly ash as alternative materials of cement. The high-fluidity concrete mixed with 50% fly ash was measured to manufacture concrete that applies low water/binder ratio to measure the mechanical characteristics as compressive strength and elastic modulus. Also, in order to evaluate the field applicability, high-fluidity concrete containing high volume fly ash was evaluated for fluidity, compressive strength, heat of hydration, and drying shrinkage of concrete.

Ultrasonic TOFD method application for steel components and welds of 10 mm wall thickness using ultrasonic flaw detector and ULTRA7 TOFD software

International Nuclear Information System (INIS)

Kasarov, R.; Tabakova, B.

2008-01-01

Pressure Vessels inspection is carried out using complex of NDT techniques. A relatively recent technique ultrasonic NDJ is the Time-of-Flight Diffraction (TOFD,) method as an effective method for detection and sizing of flaws. One of the way inspection heavy duty steel elements and welds is to use manual TOFD technique with longitudinal waves at refracted angles of 45 to 70 degrees. Typically inspections using this method have been on steel elements and welds varying from 12 mm to 300 mm wall thickness. In this paper is presented examples of using the TOFD techniques for 10 mm wall thickness using USM 35X5 and ULTRA-7 TOFD software. This software provides TOFD inspection design (PCS, sound path, beam coverage, dead zones) and validation services. The calculations of the two dead zones are derived from relatively trigonometric equation, graphically displayed on a PC-screen and weld frame form. Using ULTRA-7 TOFD the user must move the gate at which the flaw is located on PC-screen to determine the depth of defect. The diffraction points graphically displayed in a weld frame form and analyzed using geometry calculations. (authors)

Volume measurement of thalami in normal Chinese Han nationality adults by the high-resolution MRI

International Nuclear Information System (INIS)

Ma Shuai; Chen Nan; Guo Yulin

2012-01-01

Objective: To measure the volume of thalamus in 1000 healthy Chinese Han nationality adults, and to analyze the relationship between thalamic volume and age, sex, weight and cerebral volume, to provide reliable data for the construction of database of Chinese adults' digital standard brain. Methods: Totally 1000 healthy Chinese adults of Han nationality aged from 18 to 80 years were recruited.They were divided into 5 groups by age: 18-30, 31-40, 41-50, 51-60 and 61-80 years. Each group included 100 males and 100 females. Brain images were obtained on a 1.5 T MR, and the outline of thalami was drawn with Aquariusws software. Then the thalamic volume was calculated automatically. The volumes of left and right thalamus were compared by paired sample t-test. Thalamic volumes of the same side were compared between males and females by independent sample t-test. And thalamic volumes of different age groups were compared by one-way ANOVA. The relationships between thalamic volume and age, sex, weight and cerebral volume were analyzed respectively. Results: The males' standardized volumes of left and right thalamus of healthy Chinese Han nationality adults were (5776 ± 780), (5655 ± 759) mm 3 , and they were (5464 ±573), (5360 ± 542) mm 3 for female. The males' thalamic volume was more than the females' on the same side (t=2.245, 2.200, P<0.01). The left thalamic volumes of various age groups were (6180 ± 534), (6047 ± 562), (5426 ± 471), (5552 ± 526), (4866 ± 552) mm 3 , respectively, while the right thalamic volumes of the 5 groups were (6069 ± 532), (5895 ± 539), (5357 ± 480), (5396 ± 445),(4791 ± 558)mm 3 , respectively. There were statistically significant difference among the 5 groups (F=165.686, 165.235, P<0.01). The left and right thalamic volume were all negatively correlated with age (r=-0.633, -0.645, P<0.05). Conclusions: With high resolution 1.5 T MR scanner,grey matter and white matter can be depicted clearly and the outline

Water Stress from High-Volume Hydraulic Fracturing Potentially Threatens Aquatic Biodiversity and Ecosystem Services in Arkansas, United States.

Science.gov (United States)

Entrekin, Sally; Trainor, Anne; Saiers, James; Patterson, Lauren; Maloney, Kelly; Fargione, Joseph; Kiesecker, Joseph; Baruch-Mordo, Sharon; Konschnik, Katherine; Wiseman, Hannah; Nicot, Jean-Philippe; Ryan, Joseph N

2018-02-20

Demand for high-volume, short duration water withdrawals could create water stress to aquatic organisms in Fayetteville Shale streams sourced for hydraulic fracturing fluids. We estimated potential water stress using permitted water withdrawal volumes and actual water withdrawals compared to monthly median, low, and high streamflows. Risk for biological stress was considered at 20% of long-term median and 10% of high- and low-flow thresholds. Future well build-out projections estimated potential for continued stress. Most water was permitted from small, free-flowing streams and "frack" ponds (dammed streams). Permitted 12-h pumping volumes exceeded median streamflow at 50% of withdrawal sites in June, when flows were low. Daily water usage, from operator disclosures, compared to median streamflow showed possible water stress in 7-51% of catchments from June-November, respectively. If 100% of produced water was recycled, per-well water use declined by 25%, reducing threshold exceedance by 10%. Future water stress was predicted to occur in fewer catchments important for drinking water and species of conservation concern due to the decline in new well installations and increased use of recycled water. Accessible and precise withdrawal and streamflow data are critical moving forward to assess and mitigate water stress in streams that experience high-volume withdrawals.

Water stress from high-volume hydraulic fracturing potentially threatens aquatic biodiversity and ecosystem services in Arkansas, United States

Science.gov (United States)

Entrekin, Sally; Trainor, Anne; Saiers, James; Patterson, Lauren; Maloney, Kelly O.; Fargione, Joseph; Kiesecker, Joseph M.; Baruch-Mordo, Sharon; Konschnik, Katherine E.; Wiseman, Hannah; Nicot, Jean-Philippe; Ryan, Joseph N.

2018-01-01

Demand for high-volume, short duration water withdrawals could create water stress to aquatic organisms in Fayetteville Shale streams sourced for hydraulic fracturing fluids. We estimated potential water stress using permitted water withdrawal volumes and actual water withdrawals compared to monthly median, low, and high streamflows. Risk for biological stress was considered at 20% of long-term median and 10% of high- and low-flow thresholds. Future well build-out projections estimated potential for continued stress. Most water was permitted from small, free-flowing streams and “frack” ponds (dammed streams). Permitted 12-h pumping volumes exceeded median streamflow at 50% of withdrawal sites in June, when flows were low. Daily water usage, from operator disclosures, compared to median streamflow showed possible water stress in 7–51% of catchments from June–November, respectively. If 100% of produced water was recycled, per-well water use declined by 25%, reducing threshold exceedance by 10%. Future water stress was predicted to occur in fewer catchments important for drinking water and species of conservation concern due to the decline in new well installations and increased use of recycled water. Accessible and precise withdrawal and streamflow data are critical moving forward to assess and mitigate water stress in streams that experience high-volume withdrawals.

High failure rates after (131)I therapy in Graves hyperthyroidism patients with large thyroid volumes, high iodine uptake, and high iodine turnover.

Science.gov (United States)

de Jong, Jeroen A F; Verkooijen, Helena M; Valk, Gerlof D; Zelissen, Pierre M J; de Keizer, Bart

2013-06-01

The objective of this study was to identify patient characteristics positively and independently associated with I-iodide treatment failure in a large cohort of patients with Graves hyperthyroidism treated with either a calculated "standard" activity of 3.7 MBq/mL (0.1 mCi) or 7.4 MBq/mL (0.2 mCi) of thyroid volume. Data on 385 consecutive patients were prospectively collected. Clinical treatment outcome up to 1 year in relation to thyroid volume, 5- and 24-hour I uptake, 5/24-hour I uptake ratio, and the administered activity of radioiodine were analyzed. Overall treatment results were hypothyroidism in 46%, euthyroidism in 29%, and recurrent hyperthyroidism in 26% of patients. Thyroid volume (P = 0.000), 5/24-hour uptake ratio (P = 0.000), and 5- and 24-hour uptake alone (respectively, P = 0.000 and P = 0.002) were significantly associated with therapy outcome. Patients with a combination of a thyroid volume greater than 50 mL and a 5/24-hour uptake ratio 0.8 or greater showed treatment failure in 70% and 42% (respectively, 3.7 MBq/mL, n = 20; and 7.4 MBq/mL, n = 41).Thyroid volume and 5/24-hour uptake ratio were positively and independently associated with recurrent hyperthyroidism (respectively, odds ratio [OR], 5.3; 95% confidence interval [CI], 2.39-11.76; and OR, 2.97; 95% CI, 1.59-5.59). Higher activities of 7.4 MBq/mL I were associated with a lower risk of treatment failure (OR, 0.34; 95% CI, 0.18-0.62). Large thyroid volumes and high 5/24-hour uptake ratios are positively and independently associated with recurrent hyperthyroidism following I therapy in Graves hyperthyroidism. Higher success rates can be achieved when account is taken of these poor prognostic factors. In consequence, these patients should be treated with activities greater than 7.4 MBq/mL.

Amygdalar, hippocampal, and thalamic volumes in youth at high risk for development of bipolar disorder.

Science.gov (United States)

Karchemskiy, Asya; Garrett, Amy; Howe, Meghan; Adleman, Nancy; Simeonova, Diana I; Alegria, Dylan; Reiss, Allan; Chang, Kiki

2011-12-30

Children of parents with bipolar disorder (BD), especially those with attention deficit hyperactivity disorder (ADHD) and symptoms of depression or mania, are at significantly high risk for developing BD. As we have previously shown amygdalar reductions in pediatric BD, the current study examined amygdalar volumes in offspring of parents (BD offspring) who have not yet developed a full manic episode. Youth participating in the study included 22 BD offspring and 22 healthy controls of comparable age, gender, handedness, and IQ. Subjects had no history of a manic episode, but met criteria for ADHD and moderate mood symptoms. MRI was performed on a 3T GE scanner, using a 3D volumetric spoiled gradient echo series. Amygdalae were manually traced using BrainImage Java software on positionally normalized brain stacks. Bipolar offspring had similar amygdalar volumes compared to the control group. Exploratory analyses yielded no differences in hippocampal or thalamic volumes. Bipolar offspring do not show decreased amygdalar volume, possibly because these abnormalities occur after more prolonged illness rather than as a preexisting risk factor. Longitudinal studies are needed to determine whether amygdalar volumes change during and after the development of BD. 2011 Elsevier Ireland Ltd. All rights reserved.

Statistical evaluation of the mechanical properties of high-volume class F fly ash concretes

KAUST Repository

Yoon, Seyoon; Monteiro, Paulo J.M.; Macphee, Donald E.; Glasser, Fredrik P.; Imbabi, Mohammed Salah-Eldin

2014-01-01

the authors experimentally and statistically investigated the effects of mix-design factors on the mechanical properties of high-volume class F fly ash concretes. A total of 240 and 32 samples were produced and tested in the laboratory to measure compressive

Cross-correlations in volume space: Differences between buy and sell volumes

Science.gov (United States)

Lee, Sun Young; Hwang, Dong Il; Kim, Min Jae; Koh, In Gyu; Kim, Soo Yong

2011-03-01

We study the cross-correlations of buy and sell volumes on the Korean stock market in high frequency. We observe that the pulling effects of volumes are as small as that of returns. The properties of the correlations of buy and sell volumes differ. They are explained by the degree of synchronization of stock volumes. Further, the pulling effects on the minimal spanning tree are studied. In minimal spanning trees with directed links, the large pulling effects are clustered at the center, not uniformly distributed. The Epps effect of buy and sell volumes are observed. The reversal of the cross-correlations of buy and sell volumes is also detected.

Ageless Aluminum-Cerium-Based Alloys in High-Volume Die Casting for Improved Energy Efficiency

Science.gov (United States)

Stromme, Eric T.; Henderson, Hunter B.; Sims, Zachary C.; Kesler, Michael S.; Weiss, David; Ott, Ryan T.; Meng, Fanqiang; Kassoumeh, Sam; Evangelista, James; Begley, Gerald; Rios, Orlando

2018-04-01

Strong chemical reactions between Al and Ce lead to the formation of intermetallics with exceptional thermal stability. The rapid formation of intermetallics directly from the liquid phase during solidification of Al-Ce alloys leads to an ultrafine microconstituent structure that effectively strengthens as-cast alloys without further microstructural optimization via thermal processing. Die casting is a high-volume manufacturing technology that accounts for greater than 40% of all cast Al products, whereas Ce is highly overproduced as a waste product of other rare earth element (REE) mining. Reducing heat treatments would stimulate significant improvements in manufacturing energy efficiency, exceeding (megatonnes/year) per large-scale heat-treatment line. In this study, multiple compositions were evaluated with wedge mold castings to test the sensitivity of alloys to the variable solidification rate inherent in high-pressure die casting. Once a suitable composition was determined, it was successfully demonstrated at 800 lbs/h in a 600-ton die caster, after which the as-die cast parts performed similarly to ubiquitous A380 in the same geometry without requiring heat treatment. This work demonstrates the compatibility of Al REE alloys with high-volume die-casting applications with minimal heat treatments.

Ageless Aluminum-Cerium-Based Alloys in High-Volume Die Casting for Improved Energy Efficiency

Science.gov (United States)

Stromme, Eric T.; Henderson, Hunter B.; Sims, Zachary C.; Kesler, Michael S.; Weiss, David; Ott, Ryan T.; Meng, Fanqiang; Kassoumeh, Sam; Evangelista, James; Begley, Gerald; Rios, Orlando

2018-06-01

Strong chemical reactions between Al and Ce lead to the formation of intermetallics with exceptional thermal stability. The rapid formation of intermetallics directly from the liquid phase during solidification of Al-Ce alloys leads to an ultrafine microconstituent structure that effectively strengthens as-cast alloys without further microstructural optimization via thermal processing. Die casting is a high-volume manufacturing technology that accounts for greater than 40% of all cast Al products, whereas Ce is highly overproduced as a waste product of other rare earth element (REE) mining. Reducing heat treatments would stimulate significant improvements in manufacturing energy efficiency, exceeding (megatonnes/year) per large-scale heat-treatment line. In this study, multiple compositions were evaluated with wedge mold castings to test the sensitivity of alloys to the variable solidification rate inherent in high-pressure die casting. Once a suitable composition was determined, it was successfully demonstrated at 800 lbs/h in a 600-ton die caster, after which the as-die cast parts performed similarly to ubiquitous A380 in the same geometry without requiring heat treatment. This work demonstrates the compatibility of Al REE alloys with high-volume die-casting applications with minimal heat treatments.

Modeling validation to structural flaws in the foundations of oil tanks; Validacao de modelagem para estudo de alteracoes estruturais em fundacoes de tanques de petroleo

Energy Technology Data Exchange (ETDEWEB)

Couto, Larissa Goncalves; Leite, Sandro Passos, E-mail: leite_sp@ig.com.br [Fundacao Tecnico-Educacional Souza Marques, Rio de Janeiro, RJ (Brazil). Faculdade de Engenharia; Pereira, Walsan Wagner [Instituto de Radioprotecao e Dosimetria, (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2014-07-01

This paper presents the modeling of an experiment used to study the application of backscattered neutrons in the identification of structural flaws in the foundations of oil tanks. This modeling was a preliminary validation procedure of the method of calculation, performed with the radiation transport code MCNP, to study the application of backscattered neutrons as inspection tool. (author)

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

Science.gov (United States)

Claycomb, James Ronald

1998-10-01

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

Adoption of lean principles in a high-volume molecular diagnostic microbiology laboratory.

Science.gov (United States)

Mitchell, P Shawn; Mandrekar, Jayawant N; Yao, Joseph D C

2014-07-01

Clinical laboratories are constantly facing challenges to do more with less, enhance quality, improve test turnaround time, and reduce operational expenses. Experience with adopting and applying lean concepts and tools used extensively in the manufacturing industry is described for a high-volume clinical molecular microbiology laboratory, illustrating how operational success and benefits can be achieved. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Characterization of segmented large volume, high purity germanium detectors

International Nuclear Information System (INIS)

Bruyneel, B.

2006-01-01

γ-ray tracking in future HPGe arrays like AGATA will rely on pulse shape analysis (PSA) of multiple γ-interactions. For this purpose, a simple and fast procedure was developed which enabled the first full characterization of a segmented large volume HPGe detector. An analytical model for the hole mobility in a Ge crystal lattice was developed to describe the hole drift anisotropy with experimental velocity values along the crystal axis as parameters. The new model is based on the drifted Maxwellian hole distribution in Ge. It is verified by reproducing successfully experimental longitudinal hole anisotropy data. A comparison between electron and hole mobility shows large differences for the longitudinal and tangential velocity anisotropy as a function of the electrical field orientation. Measurements on a 12 fold segmented, n-type, large volume, irregular shaped HPGe detector were performed in order to determine the parameters of anisotropic mobility for electrons and holes as charge carriers created by γ-ray interactions. To characterize the electron mobility the complete outer detector surface was scanned in small steps employing photopeak interactions at 60 keV. A precise measurement of the hole drift anisotropy was performed with 356 keV rays. The drift velocity anisotropy and crystal geometry cause considerable rise time differences in pulse shapes depending on the position of the spatial charge carrier creation. Pulse shapes of direct and transient signals are reproduced by weighting potential calculations with high precision. The measured angular dependence of rise times is caused by the anisotropic mobility, crystal geometry, changing field strength and space charge effects. Preamplified signals were processed employing digital spectroscopy electronics. Response functions, crosstalk contributions and averaging procedures were taken into account implying novel methods due to the segmentation of the Ge-crystal and the digital electronics. The results are

Characterization of segmented large volume, high purity germanium detectors

Energy Technology Data Exchange (ETDEWEB)

Bruyneel, B. [Koeln Univ. (Germany). Inst. fuer Kernphysik

2006-07-01

{gamma}-ray tracking in future HPGe arrays like AGATA will rely on pulse shape analysis (PSA) of multiple {gamma}-interactions. For this purpose, a simple and fast procedure was developed which enabled the first full characterization of a segmented large volume HPGe detector. An analytical model for the hole mobility in a Ge crystal lattice was developed to describe the hole drift anisotropy with experimental velocity values along the crystal axis as parameters. The new model is based on the drifted Maxwellian hole distribution in Ge. It is verified by reproducing successfully experimental longitudinal hole anisotropy data. A comparison between electron and hole mobility shows large differences for the longitudinal and tangential velocity anisotropy as a function of the electrical field orientation. Measurements on a 12 fold segmented, n-type, large volume, irregular shaped HPGe detector were performed in order to determine the parameters of anisotropic mobility for electrons and holes as charge carriers created by {gamma}-ray interactions. To characterize the electron mobility the complete outer detector surface was scanned in small steps employing photopeak interactions at 60 keV. A precise measurement of the hole drift anisotropy was performed with 356 keV rays. The drift velocity anisotropy and crystal geometry cause considerable rise time differences in pulse shapes depending on the position of the spatial charge carrier creation. Pulse shapes of direct and transient signals are reproduced by weighting potential calculations with high precision. The measured angular dependence of rise times is caused by the anisotropic mobility, crystal geometry, changing field strength and space charge effects. Preamplified signals were processed employing digital spectroscopy electronics. Response functions, crosstalk contributions and averaging procedures were taken into account implying novel methods due to the segmentation of the Ge-crystal and the digital electronics

Nickel-base alloy overlay weld with improved ultrasonic flaw detection by magnetic stirring welding

International Nuclear Information System (INIS)

Takashi, Hirano; Kenji, Hirano; Masayuki, Watando; Takahiro, Arakawa; Minoru, Maeda

2001-01-01

Ultrasonic flaw detection is more difficult in Nickel-base alloy welds containing dendrites owing to the decrease ultrasonic transmissibility they cause. The present paper discusses application of magnetic stirring welding as a means for reducing dendrite growth with consequent improvement in ultrasonic transmissibility. Single pass and multi-pass welding tests were conducted to determine optimal welding conditions. By PT and macro observation subsequent to welding was carried out, optimal operation conditions were clarified. Overlay welding tests and UT clearly indicated ultrasonic beam transmissibility in overlay welds to be improved and detection capacity to be greater through application of magnetic stirring welding. Optimal operation conditions were determined based on examination of temper bead effects in the heat affected zone of low alloy steel by application of magnetic stirring welding to the butt welded joints between low alloy and stainless steel. Hardness in this zone of low alloy steel after the fourth layer was less than 350 HV. (author)

Evolving progress in oncologic and operative outcomes for esophageal and junctional cancer: lessons from the experience of a high-volume center.

LENUS (Irish Health Repository)

Reynolds, John V

2012-05-01

Modern series from high-volume esophageal centers report an approximate 40% 5-year survival in patients treated with curative intent and postoperative mortality rates of less than 4%. An objective analysis of factors that underpin current benchmarks within high-volume centers has not been performed.

A Bayesian approach to modeling and predicting pitting flaws in steam generator tubes

International Nuclear Information System (INIS)

Yuan, X.-X.; Mao, D.; Pandey, M.D.

2009-01-01

Steam generators in nuclear power plants have experienced varying degrees of under-deposit pitting corrosion. A probabilistic model to accurately predict pitting damage is necessary for effective life-cycle management of steam generators. This paper presents an advanced probabilistic model of pitting corrosion characterizing the inherent randomness of the pitting process and measurement uncertainties of the in-service inspection (ISI) data obtained from eddy current (EC) inspections. A Markov chain Monte Carlo simulation-based Bayesian method, enhanced by a data augmentation technique, is developed for estimating the model parameters. The proposed model is able to predict the actual pit number, the actual pit depth as well as the maximum pit depth, which is the main interest of the pitting corrosion model. The study also reveals the significance of inspection uncertainties in the modeling of pitting flaws using the ISI data: Without considering the probability-of-detection issues and measurement errors, the leakage risk resulted from the pitting corrosion would be under-estimated, despite the fact that the actual pit depth would usually be over-estimated.

Plasma uric acid and tumor volume are highly predictive of outcome in nasopharyngeal carcinoma patients receiving intensity modulated radiotherapy

International Nuclear Information System (INIS)

Lin, Hui; Lin, Huan-Xin; Ge, Nan; Wang, Hong-Zhi; Sun, Rui; Hu, Wei-Han

2013-01-01

The combined predictive value of plasma uric acid and primary tumor volume in nasopharyngeal carcinoma (NPC) patients receiving intensity modulated radiation therapy (IMRT) has not yet been determined. In this retrospective study, plasma uric acid level was measured after treatment in 130 histologically-proven NPC patients treated with IMRT. Tumor volume was calculated from treatment planning CT scans. Overall (OS), progression-free (PFS) and distant metastasis-free (DMFS) survival were compared using Kaplan-Meier analysis and the log rank test, and Cox multivariate and univariate regression models were created. Patients with a small tumor volume (<27 mL) had a significantly better DMFS, PFS and OS than patients with a large tumor volume. Patients with a high post-treatment plasma uric acid level (>301 μmol/L) had a better DMFS, PFS and OS than patients with a low post-treatment plasma uric acid level. Patients with a small tumor volume and high post-treatment plasma uric acid level had a favorable prognosis compared to patients with a large tumor volume and low post-treatment plasma uric acid level (7-year overall OS, 100% vs. 48.7%, P <0.001 and PFS, 100% vs. 69.5%, P <0.001). Post-treatment plasma uric acid level and pre-treatment tumor volume have predictive value for outcome in NPC patients receiving IMRT. NPC patients with a large tumor volume and low post-treatment plasma uric acid level may benefit from additional aggressive treatment after IMRT

Volume of hospital is important for the prognosis of high-risk patients with nonvariceal upper gastrointestinal bleeding (NVUGIB).

Science.gov (United States)

Choi, Jin Woo; Jeon, Seong Woo; Kwon, Jung Gu; Lee, Dong Wook; Ha, Chang Yoon; Cho, Kwang Bum; Jang, Byung Ik; Park, Jung Bae; Park, Youn Sun

2017-08-01

Nonvariceal upper gastrointestinal bleeding (NVUGIB) is a potentially life-threatening hospital emergency requiring hemodynamic stabilization and resuscitation. This study is carried out to determine whether hospital volume can influence outcome in patients with NVUGIB. This is a retrospective study with a prospective cohort database (KCT 0000514. cris.nih.go.kr). Eight teaching hospitals were divided into two different groups: high-volume centers (HVC, ≥60 NVUGIB patients/year, four clinics) and low-volume centers (LVC, bleeding after treatment, re-bleeding, necessity for surgical/other retreatments, and death within 30 days. Similar baseline characters for patients were observed in both groups. There was a significant difference in the incidence of poor outcome between the HVC and LVC groups (9.06 vs. 13.69%, P = 0.014). The incidence rate of poor outcome in high-risk patients (Rockall score ≥8) in HVC was lower than that in high-risk patients in LVC (16.07 vs. 26.92%, P = 0.048); however, there was no significant difference in poor outcome in the lower-risk patients in either group (8.72 vs. 10.42%, P = 0.370). Significant correlation between hospital volume and outcome in NVUGIB patients was observed. Referral to HVC for the management of high-risk NVUGIB patients should be considered in clinical practice.

Machine vision for high-precision volume measurement applied to levitated containerless material processing

International Nuclear Information System (INIS)

Bradshaw, R.C.; Schmidt, D.P.; Rogers, J.R.; Kelton, K.F.; Hyers, R.W.

2005-01-01

By combining the best practices in optical dilatometry with numerical methods, a high-speed and high-precision technique has been developed to measure the volume of levitated, containerlessly processed samples with subpixel resolution. Containerless processing provides the ability to study highly reactive materials without the possibility of contamination affecting thermophysical properties. Levitation is a common technique used to isolate a sample as it is being processed. Noncontact optical measurement of thermophysical properties is very important as traditional measuring methods cannot be used. Modern, digitally recorded images require advanced numerical routines to recover the subpixel locations of sample edges and, in turn, produce high-precision measurements

Development of a high-order finite volume method with multiblock partition techniques

Directory of Open Access Journals (Sweden)

E. M. Lemos

2012-03-01

Full Text Available This work deals with a new numerical methodology to solve the Navier-Stokes equations based on a finite volume method applied to structured meshes with co-located grids. High-order schemes used to approximate advective, diffusive and non-linear terms, connected with multiblock partition techniques, are the main contributions of this paper. Combination of these two techniques resulted in a computer code that involves high accuracy due the high-order schemes and great flexibility to generate locally refined meshes based on the multiblock approach. This computer code has been able to obtain results with higher or equal accuracy in comparison with results obtained using classical procedures, with considerably less computational effort.

High-level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 7. Revision 1

Energy Technology Data Exchange (ETDEWEB)

Burt, D.L.

1994-04-01

The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Identification Document (S/RID) is contained in multiple volumes. This document (Volume 7) presents the standards and requirements for the following sections: Occupational Safety and Health, and Environmental Protection.

High-level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 7. Revision 1

International Nuclear Information System (INIS)

Burt, D.L.

1994-04-01

The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Identification Document (S/RID) is contained in multiple volumes. This document (Volume 7) presents the standards and requirements for the following sections: Occupational Safety and Health, and Environmental Protection

Association Between Treatment at High-Volume Facilities and Improved Overall Survival in Soft Tissue Sarcomas.

Science.gov (United States)

Venigalla, Sriram; Nead, Kevin T; Sebro, Ronnie; Guttmann, David M; Sharma, Sonam; Simone, Charles B; Levin, William P; Wilson, Robert J; Weber, Kristy L; Shabason, Jacob E

2018-03-15

Soft tissue sarcomas (STS) are rare malignancies that require complex multidisciplinary management. Therefore, facilities with high sarcoma case volume may demonstrate superior outcomes. We hypothesized that STS treatment at high-volume (HV) facilities would be associated with improved overall survival (OS). Patients aged ≥18 years with nonmetastatic STS treated with surgery and radiation therapy at a single facility from 2004 through 2013 were identified from the National Cancer Database. Facilities were dichotomized into HV and low-volume (LV) cohorts based on total case volume over the study period. OS was assessed using multivariable Cox regression with propensity score-matching. Patterns of care were assessed using multivariable logistic regression analysis. Of 9025 total patients, 1578 (17%) and 7447 (83%) were treated at HV and LV facilities, respectively. On multivariable analysis, high educational attainment, larger tumor size, higher grade, and negative surgical margins were statistically significantly associated with treatment at HV facilities; conversely, black race and non-metropolitan residence were negative predictors of treatment at HV facilities. On propensity score-matched multivariable analysis, treatment at HV facilities versus LV facilities was associated with improved OS (hazard ratio, 0.87, 95% confidence interval, 0.80-0.95; P = .001). Older age, lack of insurance, greater comorbidity, larger tumor size, higher tumor grade, and positive surgical margins were associated with statistically significantly worse OS. In this observational cohort study using the National Cancer Database, receipt of surgery and radiation therapy at HV facilities was associated with improved OS in patients with STS. Potential sociodemographic disparities limit access to care at HV facilities for certain populations. Our findings highlight the importance of receipt of care at HV facilities for patients with STS and warrant further study into improving access to

Models for high cell density bioreactors must consider biomass volume fraction: Cell recycle example.

Science.gov (United States)

Monbouquette, H G

1987-06-01

Intrinsic models, which take into account biomass volume fraction, must be formulated for adequate simulation of high-biomass-density fermentations with cell recycle. Through comparison of corresponding intrinsic and non-intrinsic models in dimensionless form, constraints for non-intrinsic model usage in terms of biokinetic and fermenter operating parameters can be identified a priori. Analysis of a simple product-inhibition model indicates that the non-intrinsic approach is suitable only when the attainable biomass volume fraction in the fermentation broth is less than about 0.10. Inappropriate application of a non-intrinsic model can lead to gross errors in calculated substrate and product concentrations, substrate conversion, and volumetric productivity.

Models for high cell density bioreactors must consider biomass volume fraction: cell recycle example

Energy Technology Data Exchange (ETDEWEB)

Monbouquette, H.G.

1987-06-01

Intrinsic models, which take into account biomass volume fraction, must be formulated for adequate simulation of high-biomass-density fermentations with cell recycle. Through comparison of corresponding intrinsic and non-intrinsic models in dimensionless form, constraints for non-intrinsic model usage in terms of biokinetic and fermenter operating parameters can be identified a priori. Analysis of a simple product-inhibition model indicates that the non-intrinsic approach is suitable only when the attainable biomass volume fraction in the fermentation broth is less than about 0.10. Inappropriate application of a non-intrinsic model can lead to gross errors in calculated substrate and product concentrations, substrate conversion, and volumetric productivity. (Refs. 14).

Operating manual for the High Flux Isotope Reactor. Volume I. Description of the facility

Energy Technology Data Exchange (ETDEWEB)

1982-09-01

This volume contains a comprehensive description of the High Flux Isotope Reactor Facility. Its primary purpose is to supplement the detailed operating procedures, providing the reactor operators with background information on the various HFIR systems. The detailed operating procdures are presented in another report.

Operating manual for the High Flux Isotope Reactor. Volume I. Description of the facility

International Nuclear Information System (INIS)

1982-09-01

This volume contains a comprehensive description of the High Flux Isotope Reactor Facility. Its primary purpose is to supplement the detailed operating procedures, providing the reactor operators with background information on the various HFIR systems. The detailed operating procdures are presented in another report

76 FR 1067 - Testing of Certain High Production Volume Chemicals; Second Group of Chemicals

Science.gov (United States)

2011-01-07

... Mfg & NOES (number based criteria based criteria significant chemicals (lbs) industrial of workers... 2070-AD16 Testing of Certain High Production Volume Chemicals; Second Group of Chemicals AGENCY... section 4(a)(1)(B) of the Toxic Substances Control Act (TSCA) to require manufacturers, importers, and...

Glass Property Data and Models for Estimating High-Level Waste Glass Volume

Energy Technology Data Exchange (ETDEWEB)

Vienna, John D.; Fluegel, Alexander; Kim, Dong-Sang; Hrma, Pavel R.

2009-10-05

This report describes recent efforts to develop glass property models that can be used to help estimate the volume of high-level waste (HLW) glass that will result from vitrification of Hanford tank waste. The compositions of acceptable and processable HLW glasses need to be optimized to minimize the waste-form volume and, hence, to save cost. A database of properties and associated compositions for simulated waste glasses was collected for developing property-composition models. This database, although not comprehensive, represents a large fraction of data on waste-glass compositions and properties that were available at the time of this report. Glass property-composition models were fit to subsets of the database for several key glass properties. These models apply to a significantly broader composition space than those previously publised. These models should be considered for interim use in calculating properties of Hanford waste glasses.

Glass Property Data and Models for Estimating High-Level Waste Glass Volume

International Nuclear Information System (INIS)

Vienna, John D.; Fluegel, Alexander; Kim, Dong-Sang; Hrma, Pavel R.

2009-01-01

This report describes recent efforts to develop glass property models that can be used to help estimate the volume of high-level waste (HLW) glass that will result from vitrification of Hanford tank waste. The compositions of acceptable and processable HLW glasses need to be optimized to minimize the waste-form volume and, hence, to save cost. A database of properties and associated compositions for simulated waste glasses was collected for developing property-composition models. This database, although not comprehensive, represents a large fraction of data on waste-glass compositions and properties that were available at the time of this report. Glass property-composition models were fit to subsets of the database for several key glass properties. These models apply to a significantly broader composition space than those previously publised. These models should be considered for interim use in calculating properties of Hanford waste glasses.

Minimization of storage and disposal volumes by treatment of liquids by highly selective ion exchangers

International Nuclear Information System (INIS)

Tusa, E.; Harjula, R.; Lehto, J.

2000-01-01

Novel highly selective inorganic ion exchangers provide new efficient methods for the treatment of nuclear waste liquids. These methods have several advantages compared to conventional technologies such as evaporation, direct solidification or treatment by organic ion exchange resins. Due to high selectivity, the radionuclides can be concentrated to a very small volume even from high-salt effluents. This means that the volume waste will be very small compared to other methods, which brings considerable savings in the cost of intermediate storage and final disposal. Process equipment are highly compact and require little supervision, which brings down the capital and operation costs. The new selective inorganic ion exchangers CsTreat, SrTreat and CoTreat (manufactured by Fortum Engineering Ltd., Finland) have the highest selectivities and processing capacities, exceeding those of zeolites by several orders of magnitude. The materials are now in use in a number of nuclear sites worldwide, including those in the USA, Europe and Japan. Installations include mobile and stationary systems. Considerable experience has been gained in the use of these new materials. Lessons learned, as well as advantages and economic benefits of these highly selective exchangers will be discussed in this paper. (authors)

Thermosetting resins with high fractions of free volume and inherently low dielectric constants.

Science.gov (United States)

Lin, Liang-Kai; Hu, Chien-Chieh; Su, Wen-Chiung; Liu, Ying-Ling

2015-08-18

This work demonstrates a new class of thermosetting resins, based on Meldrum's acid (MA) derivatives, which have high fractions of free volume and inherently low k values of about 2.0 at 1 MHz. Thermal decomposition of the MA groups evolves CO2 and acetone to create air-trapped cavities so as to reduce the dielectric constants.

Use of the SONET Score to Evaluate High Volume Emergency Department Overcrowding: A Prospective Derivation and Validation Study

Directory of Open Access Journals (Sweden)

Hao Wang

2015-01-01

Full Text Available Background. The accuracy and utility of current Emergency Department (ED crowding estimation tools remain uncertain in EDs with high annual volumes. We aimed at deriving a more accurate tool to evaluate overcrowding in a high volume ED setting and determine the association between ED overcrowding and patient care outcomes. Methods. A novel scoring tool (SONET: Severely overcrowded-Overcrowded-Not overcrowded Estimation Tool was developed and validated in two EDs with both annual volumes exceeding 100,000. Patient care outcomes including the number of left without being seen (LWBS patients, average length of ED stay, ED 72-hour returns, and mortality were compared under the different crowding statuses. Results. The total number of ED patients, the number of mechanically ventilated patients, and patient acuity levels were independent risk factors affecting ED overcrowding. SONET was derived and found to better differentiate severely overcrowded, overcrowded, and not overcrowded statuses with similar results validated externally. In addition, SONET scores correlated with increased length of ED stay, number of LWBS patients, and ED 72-hour returns. Conclusions. SONET might be a better fit to determine high volume ED overcrowding. ED overcrowding negatively impacts patient care operations and often produces poor patient perceptions of standardized care delivery.

High spatiotemporal resolution measurement of regional lung air volumes from 2D phase contrast x-ray images.

Science.gov (United States)

Leong, Andrew F T; Fouras, Andreas; Islam, M Sirajul; Wallace, Megan J; Hooper, Stuart B; Kitchen, Marcus J

2013-04-01

Described herein is a new technique for measuring regional lung air volumes from two-dimensional propagation-based phase contrast x-ray (PBI) images at very high spatial and temporal resolution. Phase contrast dramatically increases lung visibility and the outlined volumetric reconstruction technique quantifies dynamic changes in respiratory function. These methods can be used for assessing pulmonary disease and injury and for optimizing mechanical ventilation techniques for preterm infants using animal models. The volumetric reconstruction combines the algorithms of temporal subtraction and single image phase retrieval (SIPR) to isolate the image of the lungs from the thoracic cage in order to measure regional lung air volumes. The SIPR algorithm was used to recover the change in projected thickness of the lungs on a pixel-by-pixel basis (pixel dimensions ≈ 16.2 μm). The technique has been validated using numerical simulation and compared results of measuring regional lung air volumes with and without the use of temporal subtraction for removing the thoracic cage. To test this approach, a series of PBI images of newborn rabbit pups mechanically ventilated at different frequencies was employed. Regional lung air volumes measured from PBI images of newborn rabbit pups showed on average an improvement of at least 20% in 16% of pixels within the lungs in comparison to that measured without the use of temporal subtraction. The majority of pixels that showed an improvement was found to be in regions occupied by bone. Applying the volumetric technique to sequences of PBI images of newborn rabbit pups, it is shown that lung aeration at birth can be highly heterogeneous. This paper presents an image segmentation technique based on temporal subtraction that has successfully been used to isolate the lungs from PBI chest images, allowing the change in lung air volume to be measured over regions as small as the pixel size. Using this technique, it is possible to measure

Volume and Surface-Enhanced Volume Negative Ion Sources

International Nuclear Information System (INIS)

Stockli, M P

2013-01-01

H - volume sources and, especially, caesiated H - volume sources are important ion sources for generating high-intensity proton beams, which then in turn generate large quantities of other particles. This chapter discusses the physics and technology of the volume production and the caesium-enhanced (surface) production of H - ions. Starting with Bacal's discovery of the H - volume production, the chapter briefly recounts the development of some H - sources, which capitalized on this process to significantly increase the production of H - beams. Another significant increase was achieved in the 1990s by adding caesiated surfaces to supplement the volume-produced ions with surface-produced ions, as illustrated with other H - sources. Finally, the focus turns to some of the experience gained when such a source was successfully ramped up in H - output and in duty factor to support the generation of 1 MW proton beams for the Spallation Neutron Source. (author)

Flaws and fallacies in statistical thinking

CERN Document Server

Campbell, Stephen K

2004-01-01

This book was written with a dual purpose: first, the author was motivated to relieve his distress over the faulty conclusions drawn from the frequent misuse of relatively simple statistical tools such as percents, graphs, and averages. Second, his objective was to create a nontechnical book that would help people make better-informed decisions by increasing their ability to judge the quality of statistical evidence. This volume achieves both, serving as a supplemental text for students taking their first course in statistics, and as a self-help guide for anyone wishing to evaluate statistica

Three-dimensional reconstruction volume: a novel method for volume measurement in kidney cancer.

Science.gov (United States)

Durso, Timothy A; Carnell, Jonathan; Turk, Thomas T; Gupta, Gopal N

2014-06-01

The role of volumetric estimation is becoming increasingly important in the staging, management, and prognostication of benign and cancerous conditions of the kidney. We evaluated the use of three-dimensional reconstruction volume (3DV) in determining renal parenchymal volumes (RPV) and renal tumor volumes (RTV). We compared 3DV with the currently available methods of volume assessment and determined its interuser reliability. RPV and RTV were assessed in 28 patients who underwent robot-assisted laparoscopic partial nephrectomy for kidney cancer. Patients with a preoperative creatinine level of kidney pre- and postsurgery overestimated 3D reconstruction volumes by 15% to 102% and 12% to 101%, respectively. In addition, volumes obtained from 3DV displayed high interuser reliability regardless of experience. 3DV provides a highly reliable way of assessing kidney volumes. Given that 3DV takes into account visible anatomy, the differences observed using previously published methods can be attributed to the failure of geometry to accurately approximate kidney or tumor shape. 3DV provides a more accurate, reproducible, and clinically useful tool for urologists looking to improve patient care using analysis related to volume.

European Registry of Carotid Artery Stenting: results from a prospective registry of eight high volume EUROPEAN institutions.