bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Peak Stress-Based and Flaw Tolerance-Based Fatigue Analysis of a Cylinder With Variable Stress Concentrations
Authors: Reinhardt Wolf , Stevens Gary L. 
Published: November 2014

To show the implications of using crack growth analysis to evaluate fatigue life, the case of a cylinder with an internal notch with a varying root radius is examined. The notch radius controls the stress gradient, where a steeper stress gradient is expected to result in slower crack growth and longer fatigue life. The notch root stress is made the same between specimens of different notch radius by scaling the applied load. As a result, the conventional fatigue analysis that calculates a fatigue usage factor from a fatigue curve based on stress at a point gives identical results for all specimens. A crack growth analysis, on the other hand, gives significantly different fatigue lives for the specimens because of the different stress gradients.
On this basis of allowable fatigue life, the traditional fatigue curve-based approach is compared with the crack growth-based flaw tolerance approach. The relative conservatism of the two approaches as a function of various parameters, including stress gradient, is discussed.
Application of the Non-Cyclic Method of Shakedown Analysis to Problems With Cyclically Moving Thermal Stress
Authors: Reinhardt Wolf , Adibi-Asl Reza 
Published: November 2014

The non-cyclic method of shakedown analysis allows the entire ratchet boundary to be determined for a given set of monotonic and cyclic loads on a component. The method is based on an extension of the lower bound shakedown theorem. Typically, the loading of interest to shakedown consists of cyclic thermal loading acting in conjunction with cyclic and monotonic (mean) primary loads, such as pressure.
To date, a certain class of spatially moving cyclic thermal loads could not be analyzed with numerical implementations of the non-cyclic method. In these cases, the mean thermal load cannot be balanced by a self-equilibrating stress state, and the component can ratchet under a purely thermal load. This paper examines why the restriction on the non-cyclic method and similar other approaches to shakedown analysis exists, and proposes an extension with the help of which an analysis of this class of problems becomes feasible. The method is demonstrated on a number of simple examples.
An Overview of Numerical Method for Fluid-Structure Interaction
Authors: Jeong J.-H. , Kim M. , Hughes P. 
Published: November 2014

Fluid-structure interaction (FSI) is the interaction of some movable or deformable structure with an internal or surrounding fluid flow. Therefore, fluid-structure interaction problems are too complex to solve analytically and so they have to be analysed by means of experiments or numerical simulation.
This paper provides an overview of numerical methods for fluid-structure interaction evaluation in an draft IAEA technical guideline: large eddy simulation (LES), direct numerical simulation (DNS), Lattice-Boltzmann method (LBM), finite element method (FEM) and computational fluid dynamics (CFD) method. In addition to providing general applications of numerical methods for fluid-structure interaction evaluation, the paper also describes some cases applied for problems associated with single-phase flow and two-phase flow in nuclear power plants.
Writing and Reviewing FEA Reports Supporting ASME Section VIII, Division 1 and 2 Designs: Practical Considerations and Recommended Good Practice
Authors: Seipp Trevor , Stonehouse Mark 
Published: November 2014

Finite element analysis (FEA) is used, with increasing frequency, to supplement or justify the design of an ASME Section VIII, Division 1 or 2 pressure vessel. When this occurs, good engineering practice indicates that a competent engineer should review the finite element analysis report. In some jurisdictions, it is required that a Professional Engineer review and certify the report.
This paper discusses some of the practical aspects of both writing and reviewing a good quality FEA report — both in the context of the technical perspective and in the context of Code compliance. This paper will serve as a practical assistant to an engineer reviewing an FEA report, as well as a guide to an engineer preparing an FEA report. Aspects such as properly following Code requirements, following appropriate Design By Analysis methodologies, and applying good design practices will be discussed.
Detection of Incipient SCC Damage in Primary Loop Piping Using Fiber Optic Strain Gages
Authors: Jackson Benjamin K. , Bosko David A. , Cronin Michael T. , Warwick Jonnathan L. W. , Wall James J. 
Published: November 2014

Current nondestructive examination (NDE) technology detection capabilities limit our ability to detect stress corrosion cracking (SCC) damage until it has progressed significantly. This work describes the continued development of an in-situ monitoring technique to detect and characterize mechanical damage caused by SCC, allowing the detection of the incipient stages of damage to components/piping. The application of this study is to prevent failures in the primary cooling loop piping in nuclear plants. The main benefit to the industry will be improved safety and component lifetime assessment with fewer inspections.
The technique utilizes high resolution fiber optic strain gages mounted on the pipe outside diameter (OD). This technique has successfully detected changes in the residual stress profile caused by a crack propagating from the pipe inside diameter (ID). The gages have a resolution of less than 1 με. It has been shown experimentally for different crack geometries that the gages can readily detect the changes of approximately 10 to 60 με caused on the OD of the pipe due to crack initiation on the ID.
This paper focuses on the latest in the development of the technology. Details of the previous work in this effort may be found in [1–3]. A short summary is provided in this paper. The main recent development was the full scale accelerated SCC cracking in boiling magnesium chloride (MgCl2) experiment. In conjunction with experimentation, both 2D and 3D finite element (FEA) models with thermal and mechanical analyses have been developed to simulate the changes in residual stresses in a welded pipe section as a SCC crack progresses.
Two Axisymmetric Models Application for Fast and Conservative Analysis of Cold Plumes in RPV at PTS Condition
Authors: Batura Anatolii , Bogdan Andrii , Orynyak Igor , Radchenko Sergii 
Published: November 2014

To determine reactor pressure vessel (RPV) residual lifetime as well as its brittle failure probability at pressurized thermal shock (PTS) conditions the original “indirect” solution method for the nonstationary temperature problem in axisymmetric formulation with the method of further stress calculation is developed. Both methods are based on transfer matrix approach and use exact analytical expressions for the thick-walled cylinders.
The automatic timestep determination method is implemented, which provides maximum calculation speed, but without the loss of the critical timepoints of scenarios under consideration. Also the accuracy of the model is improved by separate temperature calculations for “cold” plume and “hot” rest of the reactor, according to IEAE recommendations. At that axial strain of the “hot” part is used to load “cold” one.
The comparison of the methods with well-known theoretical results as well as with numerical tests demonstrates very high accuracy. It is proved by the methods of shell theory that possible difference with full 3D model of cylinder can’t be essential. Obtained fields of the temperature and stresses can be used for further estimation of the allowable value of the ductile-to-brittle transition temperature.
Effects of Metal Thickness on Bonding Strength in Bonded Dissimilar Materials
Authors: Tateno Masayoshi , Miura Takahiro 
Published: November 2014

This study provides effects of metal thickness on bonding tensile strength of ceramic to metal joint based on numerical and experimental analyses. Thermal elastoplastic FEA was carried out to clarify effects of the metal side thickness on the stress distribution near the edge of the interface on ceramic side by changing metal side thickness each bonded silicon nitride to nickel joint system. It was confirmed the stress distribution on the ceramic of the joint system depends on the metal side thickness based on the FEM results. Decreasing of metal thickness reduces the intensity of the stress near the edge of the interface on ceramics side. It can be effective for reduction of the residual stress near the edge of the interface to use thin metal layer in the ceramic to metal joint.
Reduction effects on the residual stress were confirmed by using two stages of bonding processing. This process used in this experiment consists of two stages, first bonding process as the ceramic are bonded to thin layer metal at high temperature, and secondary process as thick metal are bonded to the thin metal layer of the joint specimen at lower temperature than first stage. The bonding tensile strength of the joint specimens manufactured from the two stages bonding processe was evaluated experimentally. It appears that setting a ratio of metal thickness to length of the interface to approximate tm/W=0.08 achieves maximum bonding tensile strength. Effects of metal thickness on bonding tensile strength of ceramic to metal joint are confirmed based on numerical and experimental results.
Advancement of Lining Inspection Technology Inside Seawater Piping
Authors: Kono Yusuke , Okimura Koji , Minamiyama Akio , Noda Masaki 
Published: November 2014

Seawater piping employed for cooling of emergency diesel generator and various components at Nuclear power plant, are internally lined for protection against seawater corrosion. (Fig. 1)
However, the lining materials such as rubber or polyethylene tend to incur peel-off or crack due to aged deterioration occurred by the operation, resulting in corrosion of the piping. (Fig. 2)
Internal piping integrity of seawater piping is usually performed by periodic visual inspection. But, for the 4B to 20B pipes it has been a challenge to detect the initial degradation because the inspector cannot get into the pipes.
Pinhole detection technology that enables detection of microscopic damages and cracks is available to use as means to detect its initial state of degradation, which seems effective as preventive maintenance of the lining.
Such being the case, we are developing Seawater Piping Inside Inspection Equipment applicable to the 4B to 20B sizes of pipes by evolving the conventional pinhole detection technology.
Analysis of Crack Front Length Effect Applicable to the Evaluation of Fracture Toughness of Base Metal for PWR Pressure Vessel Steel
Authors: Joly Pierre , Benhamou Claude , Andrieu Antoine , Churier-Bossenec Henriette , Parrot Aurore 
Published: November 2014

The objective of the present paper is to review the crack front length effect (also called “specimen size effect”) on Fracture Toughness of PWR Reactor Pressure Vessel Steel base metal.
The analysis of the reality and amplitude of this effect is conducted in a first step on a database (the so called “GKSS database”) including fracture toughness test results on a single representative material using specimens of different thicknesses, tested in the same temperature range. A realistic analytical form for describing the size effect observed in this data set is thus derived from statistical analyses and proposed for engineering application.
In a second step, this size effect formulation is then applied to a large number of fracture toughness data, obtained in Irradiation Surveillance Programs, and also to the numerous data used for the definition of the ASME (and RCC-M) fracture toughness reference curves.
This analysis allows normalizing all the available fracture toughness data with a single specimen width of 100 mm and defining the fracture toughness reference curve as the lower bound of this normalized set of data points. It is thus demonstrated that the fracture toughness reference curve is associated with a reference crack length of 100 mm, and can be used in RPV integrity analyses for other crack front length in association with the crack front length correction formula defined in the first step.
Against the Odds: Community Access Radio Broadcasting during the Canterbury Earthquakes: Some reflections on Plains FM 96.9
Authors: Pauling Brian , Reece Nicki 
Published: November 2014

Plains FM is a community access radio station in Christchurch, New Zealand. Access radio is a particular form of community radio that provides an alternative outlet for organisations, groups and individuals for whom traditional media outlets are difficult to access. For twenty-five years PlainsFM has provided a voice for hundreds of programme-makers, broadcasting in many different languages, offering a diversity of content that permits the public expression of a wide range of ideas, opinions and beliefs. Editorial control lies with the programme-makers, not the station management. Plains FM is the source of many interesting, often compelling, stories. In the hours after the September 2010 earthquake Plains FM was the only local radio station actually on air. This paper draws on the memories of staff, volunteers and broadcasters to consider the unique role of the station as a media outlet during and immediately after the traumatic events of September 2010 and February 2011. It also attempts to locate those stories within the concepts of civic engagement, social utility and media theory.
Ureter tracking and segmentation in CT urography (CTU) using COMPASS
Authors: Hadjiiski Lubomir , Zick David , Chan Heang‐Ping , Cohan Richard H. , Caoili Elaine M. , Cha Kenny , Zhou Chuan , Wei Jun 
Published: November 2014

Purpose:The authors are developing a computerized system for automated segmentation of ureters in CTU, referred to as combined model‐guided path‐finding analysis and segmentation system (COMPASS). Ureter segmentation is a critical component for computer‐aided diagnosis of ureter cancer.Methods:COMPASS consists of three stages: (1) rule‐based adaptive thresholding and region growing, (2) path‐finding and propagation, and (3) edge profile extraction and feature analysis. With institutional review board approval, 79 CTU scans performed with intravenous (IV) contrast material enhancement were collected retrospectively from 79 patient files. One hundred twenty‐four ureters were selected from the 79 CTU volumes. On average, the ureters spanned 283 computed tomography slices (range: 116–399, median: 301). More than half of the ureters contained malignant or benign lesions and some had ureter wall thickening due to malignancy. A starting point for each of the 124 ureters was identified manually to initialize the tracking by COMPASS. In addition, the centerline of each ureter was manually marked and used as reference standard for evaluation of tracking performance. The performance of COMPASS was quantitatively assessed by estimating the percentage of the length that was successfully tracked and segmented for each ureter and by estimating the average distance and the average maximum distance between the computer and the manually tracked centerlines.Results:Of the 124 ureters, 120 (97%) were segmented completely (100%), 121 (98%) were segmented through at least 70%, and 123 (99%) were segmented through at least 50% of its length. In comparison, using our previous method, 85 (69%) ureters were segmented completely (100%), 100 (81%) were segmented through at least 70%, and 107 (86%) were segmented at least 50% of its length. With COMPASS, the average distance between the computer and the manually generated centerlines is 0.54 mm, and the average maximum distance is 2.02 mm. With our previous method, the average distance between the centerlines was 0.80 mm, and the average maximum distance was 3.38 mm. The improvements in the ureteral tracking length and both distance measures were statistically significant (p < 0.0001).Conclusions:COMPASS improved significantly the ureter tracking, including regions across ureter lesions, wall thickening, and the narrowing of the lumen.
Neuromuscular and Perceptual Fatigue Responses to Consecutive Tag Football Matches
Authors: Hogarth Luke W. , Burkett Brendan J. , McKean Mark R. 
Published: November 2014

Purpose:To examine the neuromuscular and perceptual fatigue responses to consecutive tag football matches played on the same day and determine the relationship between fatigue and match running performance.Methods:Neuromuscular and perceptual fatigue responses of 15 national tag football players were assessed before and during the 2014 State of Origin tournament. Global positioning systems (GPS) provided data on players’ match running performance, and a vertical-jump test and subjective questionnaire were used to assess players’ neuromuscular and perceptual fatigue, respectively.Results:There were small to moderate reductions in the majority of match-running-performance variables over consecutive matches, including distance (ES = −0.81), high-speed-running (HSR) distance (ES = −0.51), HSR efforts (ES = −0.64), and maximal accelerations (ES = −0.76). Prematch vertical jump was initially below baseline values before the first match (ES = 0.68−0.88). There were no substantial reductions in vertical-jump performance from baseline values over consecutive matches, although there was a small decline from after match 2 to after match 3 (3.3%; ES = −0.45 ± 0.62). There were progressive reductions in perceived well-being scores after matches 1 (ES = −0.38), 2 (ES = −0.70), and 3 (ES = −1.14). There were small to moderate associations between changes in fatigue measures and match running performance.Conclusions:Perceptual fatigue accumulates over consecutive tag football matches, although there were only marginal increases in neuromuscular fatigue. However, both neuromuscular and perceptual fatigue measures were found to contribute to reduced match running performance in the final match.
In Vivo
Selection of Plasmodium falciparum
Pfcrt
and
Pfmdr1
Variants by Artemether-Lumefantrine and Dihydroartemisinin-Piperaquine in Burkina Faso
Authors: Baraka Vito , Tinto Halidou , Valea Innocent , Fitzhenry Robert , Delgado-Ratto Christopher , Mbonye Martin K. , Van Overmeir Chantal , Rosanas-Urgell Anna , Van geertruyden Jean-Pierre , D'Alessandro Umberto , Erhart Annette 
Published: November 2014

ABSTRACT

Plasmodium falciparum
Pfcrt
-76 and
Pfmdr
1-86 gene polymorphisms were determined during a clinical trial in Burkina Faso comparing the efficacies of dihydroartemisinin-piperaquine (DHA-PPQ) and artemether-lumefantrine (AL). Significant selection of
Pfcrt
-K76 was observed after exposure to AL and DHA-PPQ, as well as selection of
Pfmdr
1-N86 after AL but not DHA-PPQ treatment, suggesting reverse selection on the
Pfcrt
gene by PPQ. These results support the rational use of DHA-PPQ in settings where chloroquine (CQ) resistance is high.
Systemic Antifungal Prescribing in Neonates and Children: Outcomes from the Antibiotic Resistance and Prescribing in European Children (ARPEC) Study
Authors: Lestner J. M. , Versporten A. , Doerholt K. , Warris A. , Roilides E. , Sharland M. , Bielicki J. , Goossens H. 
Published: November 2014

ABSTRACT

The appropriate use of systemic antifungals is vital in the prevention and treatment of invasive fungal infection (IFI) in immunosuppressed children and neonates. This multicenter observational study describes the inpatient prescribing practice of antifungal drugs for children and neonates and identifies factors associated with prescribing variability. A single-day point prevalence study of antimicrobial use in hospitalized neonates and children was performed between October and December 2012. The data were entered through a study-specific Web-based portal using a standardized data entry protocol. Data were recorded from 17,693 patients from 226 centers. A total of 136 centers recorded data from 1,092 children and 380 neonates receiving at least one antifungal agent. The most frequently prescribed systemic antifungals were fluconazole (
n
= 355) and amphotericin B deoxycholate (
n
= 195). The most common indications for antifungal administration in children were medical prophylaxis (
n
= 325), empirical treatment of febrile neutropenia (
n
= 122), and treatment of confirmed or suspected IFI (
n
= 100 [14%]). The treatment of suspected IFI in low-birthweight neonates accounted for the majority of prescriptions in the neonatal units (
n
= 103). An analysis of variance (ANOVA) demonstrated no significant effect of clinical indication (prophylaxis or treatment of systemic or localized infection) on the total daily dose (TDD). Fewer than one-half of the patients (
n
= 371) received a TDD within the dosing range recommended in the current guidelines. Subtherapeutic doses were prescribed in 416 cases (47%). The predominance of fluconazole and high incidence of subtherapeutic doses in participating hospitals may contribute to suboptimal clinical outcomes and an increased predominance of resistant pathogenic fungi. A global consensus on antifungal dosing and coordinated stewardship programs are needed to promote the consistent and appropriate use of antifungal drugs in neonates and children.
FabH Mutations Confer Resistance to FabF-Directed Antibiotics in Staphylococcus aureus
Authors: Parsons Joshua B. , Yao Jiangwei , Frank Matthew W. , Rock Charles O. 
Published: November 2014

ABSTRACT

Delineating the mechanisms for genetically acquired antibiotic resistance is a robust approach to target validation and anticipates the evolution of clinical drug resistance. This study defines a spectrum of mutations in
fabH
that render
Staphylococcus aureus
resistant to multiple natural products known to inhibit the elongation condensing enzyme (FabF) of bacterial type II fatty acid synthesis. Twenty independently isolated clones resistant to platensimycin, platencin, or thiolactomycin were isolated. All mutants selected against one antibiotic were cross-resistant to the other two antibiotics. Mutations were not detected in
fabF
, but the resistant strains harbored missense mutations in
fabH
. The altered amino acids clustered in and around the FabH active-site tunnel. The mutant FabH proteins were catalytically compromised based on the low activities of the purified enzymes, a fatty acid-dependent growth phenotype, and elevated expression of the
fabHF
operon in the mutant strains. Independent manipulation of
fabF
and
fabH
expression levels showed that the FabH/FabF activity ratio was a major determinant of antibiotic sensitivity. Missense mutations that reduce FabH activity are sufficient to confer resistance to multiple antibiotics that bind to the FabF acyl-enzyme intermediate in
S. aureus
.