bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flaw Evaluation Procedure for Cast Austenitic Stainless Steel Materials Using Thermal Aging Models
Authors: Uddin M. F. , Wilkowski G. M. , Pothana S. , Brust F. W. 
Published: October 2017

Thermal embrittlement of cast austenitic stainless steels (CASS) can occur at reactor operating temperatures potentially leading to a reduction in their fracture toughness. Some aged CASS materials have the potential to have exceedingly low toughness and also show high toughness variability due to the nature of their microstructure. The experimentally measured JIc values for CASS materials showed a large scatter when plotted against ferrite number (FN) or chrome equivalent number (Creq). Because of their low aged toughness with such a large variability, flaw evaluations of CASS material needs to be done carefully, especially since most US PWR nuclear plants have been given plant-life extensions for 60-year operation, and consideration of further extension to 80 years is underway. However, the ASME Section XI Appendix C flaw acceptance criterion currently does not have a recommended procedure for flaw evaluation for CASS materials with FN ≥ 20, and the Working Group recognizes that the changes might also be needed for CASS with FN less than 20.
In this paper, a flaw evaluation procedure for fully aged CASS materials is presented using JIc values at LWR operating temperatures predicted from several existing thermal-aging toughness degradation models. All available thermal aging models for CASS materials were evaluated which predict fully aged (lower saturated toughness condition) fracture toughness of CASS based on their chemical compositions. A set of 20 experimental test data was analyzed by using all models to find the most accurate thermal aging models. Using the most accurate models, correlations between predicted JIc values and French Creq-Fr and ASTM A800 FN were developed from a database of 274 pipe/elbows in US PWR plants whose chemical compositions were known. Finally, the correlation was used to determine the elastic-plastic fracture correction factor (Z factor) for CASS pipe and fittings as a function of pipe diameter and their chemical compositions from material certification sheet using the Dimensionless-Plastic-Zone-Parameter (DPZP) analysis. The DPZP analysis is a relatively simple curve-fitting procedure through full-scale circumferential surface-cracked pipe tests developed in pipe fracture projects funded by the USNRC, and was checked against a full-scale aged CF8m pipe fracture test. After determining the chemical composition specific Z factor for CASS materials, the flaw evaluation can be performed according to the ASME Section XI Appendix C procedures.
ASME Pressure Design of Class 1 Pipe Bends Using Elastic-Plastic FEA
Authors: Abdelsalam Usama , Glover Andrew , Vijay Dk 
Published: October 2017

In a previous paper, it was demonstrated that a tight radius bend with uniform wall thickness equal to the pressure based thickness of the corresponding straight pipe does not meet the linear elastic criteria of NB-3221 Design Loadings. It was also demonstrated that the allowable wall thickness circumferential distribution of the ASME B&PV Code SEC XI Code Case N-597-2 achieves a uniform linear elastic stress intensity over the entire bend that meets the linear elastic criteria of NB-3221. As stated by the ASME B&PV Code under NB-3221, the provisions of NB-3228 may provide relief from certain of the linear elastic stress limits if plastic analysis techniques are applied.
In this paper, the plastic collapse analysis approach of the COG FFSG is adopted to explore the relative safety margin when analyzing various Class 1 tight radius pipe bends’ configurations made of Carbon Steel SA-106 Grade B. In addition to the power law material model, three elastic plastic material models are constructed based on ASME B&PV Code Section II Part D material properties. The pressure-based thickness for the same size straight pipe is uniformly used in modelling the tight radius bends (no increased thickness on the intrados). It is demonstrated that the results from the ASME B&PV based flow stress model are marginal and that the ASME B&PV based bi-linear material model and the limit analysis results are not meeting the collapse pressure criterion. It is also demonstrated that the uniform pressure-based thickness along with the power law material model meets the requirements for the adopted plastic collapse pressure providing a considerable life extension.
Solution of a Sample Problem Related to Revision 1 of Code Case N-830
Authors: Kirk Mark , Xu Steven , Lui Cheng , Erickson Marjorie , Kim Yil , Lee Darrell , Shim Do Jun , Stevens Gary 
Published: October 2017

Within the American Society of Mechanical Engineers (ASME) the Section XI Working Group on Flaw Evaluation (WGFE) is currently working to develop a revision to Code Case (CC) N-830. CC N-830 permits the direct use of fracture toughness in flaw evaluations as an alternative to the indirect/correlative approaches (RTNDT-based) traditionally used in the ASME Code. The current version of N-830 estimates allowable fracture toughness values in the transition regime as the 5th percentile Master Curve (MC) indexed to the transition temperature T0. The proposed CC N-830 revision expands on this capability by incorporating a complete and self-consistent suite of models that describe completely the temperature dependence, scatter, and interdependencies between all fracture metrics (i.e., KJc, KIa, JIc, J0.1, and J–R) used currently, or useful in, a flaw evaluation for conditions ranging from the lower shelf through the upper shelf. Papers presented in previous ASME Pressure Vessel and Piping (PVP) Conferences since 2014 provide the technical basis for these various toughness models.
This paper contributes to this overall CC N-830 documentation suite by presenting the results of a sample problem run to assess the proposed revision of the CC. The objective of the sample problem was (1) to determine if the revised CC was written with adequate clarity to permit different engineers to accurately and consistently calculate the various allowable toughness values described by the equations in the CC, (2) to assess how these allowable toughness values would be used to calculate allowable flaw depths using standard ASME SC-XI approaches, and (3) to compare allowable flaw depths calculated using established Code practices (RTNDT-based) to those calculated using proposed CC practices (T0-based). The sample problem demonstrated that (1) the CC was written with sufficient clarity to allow different engineers to arrive at the same estimated value of allowable toughness, (2) the latitude associated with the provisions of the ASME Code pertinent to estimation of allowable flaw depth are responsible for some differences in the allowable flaw depth values reported by different participants, and (3) current Code estimates of allowable flaw depth are far more conservative (that is: smaller) than values estimated by the candidate CC methods based on the MC, this mostly due to the generally-conservative bias of the Code’s RTNDT & KIc approach. The candidate CC methods provide much more consistent conservatism than current Code approaches for all conditions in the operating nuclear reactor fleet via their use of an index temperature (T0) defined by actual fracture toughness data and a temperature dependence defined by those data.
The WGFE is continuing to evaluate candidate approaches to estimate allowable toughness values for CC N-830 using a T0-indexed Master Curve. Associated work is addressed by two companion papers presented at this conference.
Fitness-for-Service Assessment of Steam Generator Tubing Subject to Dealloying Degradation
Authors: Mousavi Rosita , Duan Xinjian , Kozluk Michael , Wang Min , Shi Yihai 
Published: October 2017

A new degradation mechanism has been observed in Monel 400 Steam Generator tubing material, a nickel-copper alloy (63Ni-28Cu-2½Fe) with the ASME material designation SB-163/N04400. The location is above the top preheater support plate of the two re-circulating steam generator in one of the units of the Pickering Nuclear Generating Station.
This paper provides a brief description of the regulatory environment, OPG’s steam generator life cycle management plans, the Canadian Industry’s fitness-for-service guidelines for steam generator tubes, and the afflicted steam generators. The paper then goes on to discuss the following activities that were conducted to support the technical basis to justify that the steam generators fit to be returned to service:
• Inspection scope expansion, methods, and results.
• Examination of removed tubes.
• Condition monitoring assessment.
• Operational assessment.
• Burst-pressure tests of removed tubes and of fabricated test specimens.
• Degradation specific flaw model and acceptance standards.
• Flaw growth rate predictions.
• Plugging limit adopted.
Applicability of Miniature C(T) Specimen to Fracture Toughness Evaluation for the Irradiated Japanese Reactor Pressure Vessel Steel
Authors: Sugihara Takuji , Hirota Takatoshi , Sakamoto Hiroyuki , Yoshimoto Kentaro , Tsutsumi Kazuya , Murakami Takeshi 
Published: October 2017

Fracture toughness evaluations for irradiated reactor pressure vessel (RPV) steels are essential in the structural integrity assessment of RPVs. In Japanese pressurized water reactor (PWR) plants, fracture toughness tests are conducted for irradiated RPV steels through the surveillance tests and fracture toughness data are obtained. Lately, the Master Curve (MC) approach has become the main stream in fracture toughness evaluation. However, there can be the case that the number of fracture toughness data is not enough for the MC method in some Japanese PWR plants because of limited numbers of fracture toughness specimens contained in the surveillance capsules. On the other hand, for the Japanese PWR plants, a surveillance capsule generally contains a lot of Charpy impact specimens which miniature C(T) (Mini-C(T)) specimens with a size of 4×10×9.6mm can be taken from. Therefore, it is planned that additional fracture toughness tests are performed using Mini-C(T) specimens after the Charpy impact tests to obtain sufficient fracture toughness data for the MC method.
Applicability of the Mini-C(T) specimen to the MC evaluation has been studied in a series of international round robin test programs coordinated by Central Research Institute of Electric Power Industry (CRIEPI). In these programs and the related studies, it was demonstrated that the reference temperature (To) can be determined by the Mini-C(T) specimens without any specific difficulties for the unirradiated RPV base metals. In addition, CRIEPI has recently reported on the basis of their studies that the fracture toughness tests could be successfully performed on the typical unirradiated RPV weld metal and the valid To can be determined with the data obtained from the weld metal as well as base metals. However, few papers reported applicability of the Mini-C(T) specimen to the MC evaluation for irradiated RPV steels.
In this study, fracture toughness tests using Mini-C(T) specimens were conducted on the irradiated Japanese Industrial Standards (JIS) SFVQ1A steel (equivalent to ASME A508 Cl.3 steel). The Mini-C(T) specimens were machined out from some broken halves of Charpy impact specimens used in a surveillance test of an actual Japanese PWR plant by a wire cut electric spark machine followed by fatigue precracking. After the fracture toughness tests, the evaluation was performed on the obtained fracture toughness data according to the MC method. The effect of specimen size on To was studied and applicability of the Mini-C(T) specimen was discussed by comparing the existing results of fracture toughness tests using the 1/2T-C(T) specimens conducted in the surveillance test. In addition, the issues to obtain valid To for irradiated materials were discussed.
Consideration of Reduction in Stiffness due to Cracking and the Impact on Standard Stress Intensity Factor Solutions
Authors: Blanks Daniel M. 
Published: October 2017

An API 579-1/ASME FFS-1 Failure Assessment Diagram based Fitness-for-Service assessment was carried out on an embedded crack-like flaw found in a nozzle to shell weld in a pressure vessel. Stress intensity factors were initially calculated by utilizing stress results from a Finite Element Analysis (FEA) of an uncracked configuration, with the standard embedded crack stress intensity factor solution given in API 579-1/ASME FFS-1. Due to the complex nozzle geometry and flaw size, a second analysis was carried out, incorporating a crack into the FEA model, to calculate the stress intensity factors and evaluate if the standard solution could be applied to this geometry.
A large difference in the resulting stress intensity factors was observed, with those calculated by the FEA with the crack incorporated into the model to be twice as high as those calculated by the standard solutions, indicating the standard embedded crack stress intensity factor solution may be non-conservative in this case. An investigation was carried out involving a number of studies to determine the cause of the difference. Beginning with an elliptical shaped embedded crack in a plate, the stress intensity factor calculated with an idealized 3D crack mesh agreed with the API 579-1/ASME FFS-1 solution. Examining other crack locations, and crack shapes, such as a constant depth embedded crack, revealed how the solution began to differ.
The greatest difference was found when considering a crack mesh with a small component height (i.e. the distance measured perpendicular from the crack face to the top of the mesh). A close agreement was then found between the stress intensity factors calculated in the nozzle model and an idealized crack mesh with component heights representative of the true geometry. This revealed that reduced structural stiffness is a key factor in the calculation of the stress intensity factors for this geometry, due to the close proximity of the embedded crack to the inner surface of the nozzle. It was found that this reduction is potentially significant even with relatively small crack sizes.
This paper details the investigation, and aims to provide the reader with an awareness of situations when the standard stress intensity factor solutions may no longer be valid, and offers general recommendations to consider when calculating stress intensity factors in these situations.
Antimicrobial resistance in UK neonatal units: neonIN infection surveillance network
Authors: Cailes Benjamin , Kortsalioudaki Christina , Buttery Jim , Pattnayak Santosh , Greenough Anne , Matthes Jean , Bedford Russell Alison , Kennea Nigel , Heath Paul T 
Published: October 2017

ObjectiveTo define the susceptibilities of the common causative pathogens of neonatal sepsis in the UK.DesignRetrospective analysis of the prospectively collected neonIN infection surveillance network data between 2005 and 2014.Setting30 neonatal units in the UK.PatientsNewborns admitted to participating neonatal units who return a positive blood, cerebrospinal fluid or urine culture and are treated with at least 5 days of appropriate antibiotics.Results1568 isolates with recorded antimicrobial data were collected including 328 early-onset sepsis (EOS) isolates and 1240 late-onset sepsis (LOS) isolates. The majority of EOS pathogens (>92%) were susceptible to the four empirical commonly used antimicrobial combinations (eg, 93% for benzylpenicillin/gentamicin), while LOS pathogens demonstrated higher levels of resistance (eg, 89% for flucloxacillin/gentamicin). Among infants<1500 g and <32 weeks gestation, an amoxicillin/gentamicin combination demonstrated a trend towards improved coverage of EOS isolates than benzylpenicillin/gentamicin (93% vs 86%, p=0.211).ConclusionsThis analysis provides insights into the patterns of antimicrobial resistance among UK neonatal pathogens. These data will inform areas of future research and can be used to update national evidence-based guidelines on antimicrobial usage.
The impact of out-of-hospital models of care on paediatric emergency department presentations
Authors: Viner Russell M , Blackburn Frances , White Francesca , Mannie Randy , Parr Tracy , Nelson Sara , Lemer Claire , Riddell Anna , Watson Mando , Cleugh Francesca , Heys Michelle , Hargreaves Dougal S 
Published: October 2017

ObjectiveTo estimate the potential impact of enhanced primary care and new out-of-hospital models (OOHMs) on emergency department (ED) presentations by children and young people (CYP).DesignObservational study.Patients & settingData collected prospectively on 3020 CYP 0–17.9 years from 6 London EDs during 14 days by 25 supernumerary clinicians. CYP with transient acute illness, exacerbation of long-term condition (LTC), complex LTC/disability and injury/trauma were considered manageable within OOHM. OOHMs assessed included nurse-led services, multispecialty community provider (MCP), primary and acute care system (PACS) plus current and enhanced primary care.MeasuresDiagnosis, severity; record of investigations, management and outcome that occurred; objective assessment of clinical need and potential alternative management options/destinations.ResultsOf the patients 95.6% had diagnoses appropriate for OOHM. Most presentations required assessment by a clinician with skills in assessing illness (39.6%) or injuries (30.9%). One thousand two hundred and ninety-one (42.75%) required no investigations and 1007 (33.3%) were provided only with reassurance. Of the presentations 42.2% were judged to have been totally avoidable if the family had had better health education.Of the patients 26.1% were judged appropriate for current primary care (community pharmacy or general practice) with 31.5% appropriate for the combination of enhanced general practice and community pharmacy. Proportions suitable for new models were 14.1% for the nurse-led acute illness team, MCP 25.7%, GP federation CYP service 44.6%, comprehensive walk-in centre for CYP 64.3% and 75.5% for a PACS.ConclusionsHigh proportions of ED presentations by CYP could potentially be managed in new OOHMs or by enhancement of existing primary care.
Outcome of anti-vascular endothelial growth factor therapy for neovascular age-related macular degeneration in real-life setting
Authors: Kataja Maria , Hujanen Pekko , Huhtala Heini , Kaarniranta Kai , Tuulonen Anja , Uusitalo-Jarvinen Hannele 
Published: October 2017

AimsTo evaluate outcome of anti-vascular endothelial growth factor (VEGF) therapy for the treatment of neovascular age-related macular degeneration (nAMD) in the real-life setting and to compare incidence of ocular serious adverse events (SAE) after injections administered by nurses and physicians.MethodsRetrospective, single-centre study. Medical records of patients receiving anti-VEGF treatment for nAMD between 2008 and 2013 with three-loading-dose regimen were evaluated. Outcome measures were baseline visual acuity (VA), change in VA, number of intravitreal injections, incidence of ocular SAE and patients’ baseline characteristics affecting VA change. In addition, the number of injections per 1000 citizens living in the serving area and per individuals over 65 years old were estimated.Results1349 eyes in 1117 patients received a total of 11 562 intravitreal anti-VEGF injections. Twenty-one per cent of patients received treatment for both eyes. The mean baseline Snellen VA was 0.32. The mean change of VA from baseline was +2, +2 and ±0 Early Treatment Diabetic Retinopathy Study letters and the mean numbers of injections were 5.7, 4.7 and 4.9 at years 1, 2 and 3, respectively. There was a negative correlation between baseline VA and change of VA. Incidence of endophthalmitis was 0.086%. No difference in the incidence of ocular SAE was identified between injections given by nurses or by physicians. The number of intravitreal injections per all citizens was 9 per 1000 inhabitants and 45 per 1000 inhabitants over 65 years.ConclusionThe VA was maintained at the baseline level (±0 letters) with the mean of 15.3 anti-VEGF injections in real-world clinical practice during 3-year follow-up.
Effectiveness of school-based physical activity programmes on cardiorespiratory fitness in children: a meta-analysis of randomised controlled trials
Authors: Pozuelo-Carrascosa Diana P , García-Hermoso Antonio , Álvarez-Bueno Celia , Sánchez-López Mairena , Martinez-Vizcaino Vicente 
Published: October 2017

ObjectiveTo conduct a meta-analysis of randomised controlled trials aimed at testing whether school-based physical activity programmes improve cardiorespiratory fitness (CRF) in children.DesignSystematic review with meta-analysis.Data sourcesUsing keywords, we performed a computerised search in five databases: MEDLINE, EMBASE, CINAHL, Web of Science and SportDiscus.Eligibility criteria for selecting studiesStudies that assessed the effectiveness of school-based physical activity programmes on improving CRF in children (3–12 years old). We selected interventions that included an additional physical activity programme and not only a physical activity educational component. The reference lists of selected full-text articles and systematic reviews were also searched for relevant studies. Pooled effect size (Hedges′g) was calculated assuming a random-effects model.ResultsTwenty trials with 7287 healthy children aged 3–12 years were included in the meta-analysis. School-based physical activity interventions with aerobic games and activities were associated with a significant small increase in CRF (Hedges′g=0.22; 95% CI 0.14 to 0.30; p<0.001). Based on subgroup analysis, the increase in CRF was significant in girls (Hedges′g=0.25; 95% CI 0.13 to 0.37; p<0.001), but not in boys (Hedges′g=0.02; 95% CI −0.10 to 0.14; p=0.731).SummaryModerate quality evidence supports the effectiveness of school-based physical activity interventions on improving CRF in children.Trial registration numberProtocol PROSPERO registration numberCRD42016050173.
Connective tissue injury in calf muscle tears and return to play: MRI correlation
Authors: Prakash Ashutosh , Entwisle Tom , Schneider Michal , Brukner Peter , Connell David 
Published: October 2017

ObjectiveThe aim of our study was to assess a group of patients with calf muscle tears and evaluate the integrity of the connective tissue boundaries and interfaces. Further, we propose a novel MRI grading system based on integrity of the connective tissue and assess any correlation between the grading score and time to return to play. We have also reviewed the anatomy of the calf muscles.Materials and methodsWe retrospectively evaluated 100 consecutive patients with clinical suspicion and MRI confirmation of calf muscle injury. We evaluated each calf muscle tear with MRI for the particular muscle injured, location of injury within the muscle and integrity of the connective tissue structure at the interface. The muscle tears were graded 0–3 depending on the degree of muscle and connective tissue injury. The time to return to play for each patient and each injury was found from the injury records and respective sports doctors.ResultsIn 100 patients, 114 injuries were detected. Connective tissue involvement was observed in 63 out of 100 patients and failure (grade 3 injury) in 18. Mean time to return to play with grade 0 injuries was 8 days, grade 1 tears was 17 days, grade 2 tears was 25 days and grade 3 tears was 48 days (p<0.001).ConclusionThe integrity of the connective tissue can be used to estimate and guide the time to return to play in calf muscle tears.