bluuebunny/crossref_metadata_2025_split huggingface dataset:
Discussions on Effects of Temperature in Fatigue Assessment of Stainless NPP Primary Piping
Authors: Solin Jussi , Curtit François , Blatman Géraud , Karabaki H. Ertugrul , Métais Thomas , Mayinger Wolfgang 
Published: October 2017

Fatigue performance of Nuclear Power Plant (NPP) primary circuit components and laboratory specimens depends on temperature. Temperature plays a particular role in environmental fatigue, but affects also generic fatigue evaluations.
Historically, fatigue data was generated in air at room temperature using strain-control testing. For the purpose of engineering calculations, the strain was then transformed into “stress intensity”. The elastic-plastic strains were scaled to pseudo-stress units (psi or MPa) via the use of an elastic modulus. To make a single curve useable over a range of temperatures an adjusting factor was implemented in the codified stress analysis. The ratio of elastic modulus in the design and room temperatures was considered applicable to adjust the stress intensity (total strain) used in fatigue assessment.
Later on, temperature dependent factors were proposed for environmental effects {Fen = Nf(RT,air) / Nf(T,environment)}. Also environment independent temperature effects are covered by Fen factors, which are used to multiply fatigue usage. This means that temperature is supposed to be accounted for twice in fatigue assessments: first for stress intensity, then for allowable cycles. Moreover, fatigue data in high temperatures have been included in the data set behind the current design curve for stainless steels.
Incompatible corrections and code updates can lead to some over-conservatism when selecting adequate values for the elastic modulus and Fen for the fatigue calculations. Given the construction of the design curve as an integral part of the original codified assessment procedure, new developments in numerical stress analysis and experiments together with aim to perform calculations as consistent as possible with the physics at hand, a proposal is made in this paper to define a method to evaluate fatigue using strain amplitude rather than stress intensity amplitude.
A concern on double counting of temperature effects and inaccuracies in fatigue assessment was raised by the current authors [1] [2], but this issue has not yet been studied and discussed in depth. This paper will discuss effects of temperature in fatigue experiments and assessment in terms of transferability of laboratory data for fatigue assessment. Among others, a statistical study based on laboratory test results in Pressurized Water Reactor (PWR) environment will help identify possible gaps between the recorded fatigue lives and the values provided by the codified rules. The aim is to quantitatively analyze the ranges of inaccuracies and unknowns affecting fatigue assessment of NPP components in various operational temperatures.
Fracture Mechanics Analyses of Embedded Cracks Under PTS and Effects of Residual Stresses
Authors: Qian Guian , González-Albuixech V. F. , Niffenegger Markus 
Published: October 2017

One potential challenge to the integrity of a reactor pressure vessel (RPV) of a pressurized water reactor is posed by a pressurized thermal shock (PTS), which is associated with severe cooling of the RPV followed by its repressurization. PTS transients lead to high tensile circumferential and axial stresses in the RPV wall. If the stress intensity factor (SIF) is large enough, a critical crack may grow. Thus, the RPV has to be assessed against cleavage fracture.
In this paper, two kinds of embedded cracks, i.e. semielliptical and elliptical crack with depth of 17 mm and length of 102 mm are considered. The extended finite element method (XFEM) is used to model such postulated cracks. The embedded crack with tip in the cladding/base interface causes a high KI. This is due to the stress discontinuities at the interface between the materials. In the FAVOR (probabilistic fracture mechanics code) calculation, for such cracks the closest point to the inner surface is calculated in order to be conservative. However, due to the highly ductile cladding material, it is unlikely for the embedded crack to propagate through the cladding. Thus, it is more appropriate to consider the outer surface point of the crack front.
The effect of welding residual stress and cladding/base interface residual stress on the crack driving force is studied. Surface cracks are assumed in the study of residual stresses. Results show that considering realistic welding residual stresses may increase KI by about 5 MPa·m0.5, while the cladding/base interface residual stress has a negligible effect on KI. The reason is that the cladding residual stress is only localized to the interface and it decreases significantly through the vessel wall.
Organization of the Independent Safety Review Done by Electrabel for the Safety Assessment of Doel 3 and Tihange 2 RPVs
Authors: Meert Arnaud , De Cock Jean-Paul 
Published: October 2017

The paper will deal with the way Electrabel carried out an independent control of the safety case studies of Doel 3 and Tihange 2 Reactor Pressure Vessels assessments after the discovery of indications of hydrogen induced flakes.
Electrabel’s Physical Control Service (Service de Contrôle Physique: SCP), acting as an internal independent body, has been involved since the very beginning of the development of the Safety Case. Its objective has been to perform an independent review of the project deliverables issued by the Project Team.
Several independent evaluations were carried out. Some were externalised: for instance Sandia National Laboratories performed calculations with an independent methodology to challenge the project grouping methodology; they also assessed the UT technique used for the non-destructive tests. Others were done internally: for instance, statistical calculations were performed during the UT qualification process, leading to a recommendation to increase the detection level.
SCP also provided its recommendations when determining the fluence level for the irradiation campaigns done in the BR-2 reactor. This helped to challenge the correlations established for the Safety Case by the Project Team.
The paper will detail the way the SCP was organised, the scope of its activities and reviews. It will detail the legal process of independent review as requested by the Belgian legal framework. It will also detail some specific actions carried out as the Sandia counter-study and some external expertise performed.
During the whole assessment process, SCP produced several reports, synthetized in the final advise: ‘Report on independent analysis and advice regarding the Safety Case’ and its addendum, published on the website of the FANC. This late one covered the full project scope (Safety Case 2015 Version1), ranging from the preliminary studies, proceedings of mechanical tests, and draft documents up to the final justification file that was delivered to the Safety Authorities on 28 October 2015. An overview of those reports, the concerns and the solution found and finally the approbation of the action plan will be described.
Nevertheless, the paper will not address the part of the review done by the Regulatory Body and its Technical Support Organization as it is out of the scope of the SCP activities.
Comparison of Strip Yield and Net Section Plasticity Models for a Bar in Bending With a Single Edge Crack
Authors: Reinhardt Wolf , Metzger Don 
Published: October 2017

The strip yield model is widely used to describe crack tip plasticity in front of a crack. In the strip yield model the stress in the plastic zone is considered as known, and stress and deformation fields can be obtained from elastic solutions using the condition that the crack tip stress singularity vanishes.
The strip yield model is generally regarded to be valid to describe small scale plasticity at a crack tip. The present paper examines the behavior of the strip yield model at the transition to large-scale plasticity and its relationship to net section plasticity descriptions. A bar in bending with a single edge crack is used as an illustrative example to derive solutions and compare with one-sided and two-sided plasticity solutions.
Load Monitoring and Condition Assessment of High-Pressure-High-Temperature (HPHT) Subsea Facilities
Authors: Shavandi Mohsen , Tang Fei 
Published: October 2017

High Pressure - High Temperature (HPHT) design is a significant new challenge facing the subsea sector, particularly in the Gulf of Mexico. For fatigue-sensitive applications, the current regulations in the Gulf of Mexico will require operators to compare the actual load cycles experienced by the HPHT component to the load cycles used in the design verification analyses. Should the analyses show that the HPHT equipment is experiencing loading combinations that are greater than those anticipated in the original design, a new service life (loads, time in service, and cycles) based on the actual loads and cycles needs to be developed.
The condition assessment in other industries is mainly inspection-based, while inspection of subsea equipment at fatigue-sensitive locations during operation may not be practical. Thus, load monitoring and condition assessment of subsea facilities is a major challenge that the subsea industry is facing.
Several assessment methods were evaluated as part of this study, including use of available monitoring technologies in combination with analytical methods. The key findings are summarized to help establish the proper Load Monitoring Program (LMP) for HPHT subsea applications.
Swelling Characteristics of a Type 304SS Baffle Plate Irradiated up to 50 DPA in PWR and Validation of a Swelling Equation
Authors: Mogami Yuichi , Matsubara Toru , Yaguchi Seiji , Tsuda Tomohiro , Fujimoto Koji 
Published: October 2017

When austenitic stainless steel is highly irradiated in a reactor under high temperature, voids will be created in the material, leading to volumetric expansion of structures. This phenomenon is known as void swelling. The deformation caused by the swelling possibly deteriorates the functionality of reactor internals in Pressurized Water Reactors (PWRs), especially baffle former assemblies. To evaluate the functionality of the internals against the swelling and to assure the structural integrity, simulation technologies play a key role, enabling the estimation of the swelling behavior of the internals through plant life. The simulation results strongly depend on inputs, especially on a swelling equation; however, it includes uncertainty to some extent because quite limited swelling data in PWR environment have been available, which are necessary for the validation of the equation.
To enable the validation of swelling equations and improve the reliability on the simulations, the authors investigated the swelling characteristics of a type 304SS baffle plate removed from a decommissioned PWR plant. A total of nine swelling data were obtained with the variety in neutron dose (33 to 47 dpa) and irradiation temperature (299 to 327°C). The swelling ratios obtained are ranging from 0.02 to 0.08%, which corresponds well with the swelling equation, showing the similar temperature dependency with the equation. Since the irradiation temperature range of the obtained data, up to 327°C, covers major part of baffle former assemblies, swelling ratios of most part of them are expected to be small, which is probably too small to harm the functionality of the assemblies. The results contribute to the better confidence on swelling simulations and to assure the integrity of PWR reactor internals.
Mechanical Properties of Dealloyed Aluminum Bronze Large-Bore Castings in Essential Cooling Water Service
Authors: Cipolla Russell C. , Garner Michael , Aldridge Arden J. 
Published: October 2017

Metal loss caused by selective leaching of aluminum (referred to herein as dealloying) in certain aluminum-bronze (Al-Brz) alloys is an environmentally-induced degradation mechanism in piping systems containing cast components exposed to marine, brackish, or raw water service. Examples of this form of degradation have been observed in ASME Code Class 3 Essential Cooling Water systems. Mechanical properties for tensile strength and fracture toughness of Al-Brz static and centrifugal castings, fabricated to ASME SB-148 CA952 and CA954 specifications, can locally degrade in service due to dealloying under long exposure to aggressive water environments.
This paper presents the results on the reduction in mechanical strength as a result of dealloying. A mechanical testing program was completed where 20 tensile and 22 fracture toughness specimens were tested to determine the reduction in mechanical properties from no dealloying (virgin condition) to various amounts of dealloying up to 100% dealloyed condition measured across the specimen. The specimens were fabricated from components removed from service (some components being in service for over 25 years). The data were plotted as a function of percent dealloying where a systematic decrease in properties was seen directly dependent the amount of dealloyed material in the cross-section of the specimen.
Phenotypic diversity in autosomal-dominant cone-rod dystrophy elucidated by adaptive optics retinal imaging
Authors: Song Hongxin , Rossi Ethan A , Stone Edwin , Latchney Lisa , Williams David , Dubra Alfredo , Chung Mina 
Published: October 2017

PurposeSeveral genes causing autosomal-dominant cone-rod dystrophy (AD-CRD) have been identified. However, the mechanisms by which genetic mutations lead to cellular loss in human disease remain poorly understood. Here we combine genotyping with high-resolution adaptive optics retinal imaging to elucidate the retinal phenotype at a cellular level in patients with AD-CRD harbouring a defect in the GUCA1A gene.MethodsNine affected members of a four-generation AD-CRD pedigree and three unaffected first-degree relatives underwent clinical examinations including visual acuity, fundus examination, Goldmann perimetry, spectral domain optical coherence tomography and electroretinography. Genome-wide scan followed by bidirectional sequencing was performed on all affected participants. High-resolution imaging using a custom adaptive optics scanning light ophthalmoscope (AOSLO) was performed for selected participants.ResultsClinical evaluations showed a range of disease severity from normal fundus appearance in teenaged patients to pronounced macular atrophy in older patients. Molecular genetic testing showed a mutation in in GUCA1A segregating with disease. AOSLO imaging revealed that of the two teenage patients with mild disease, one had severe disruption of the photoreceptor mosaic while the other had a normal cone mosaic.ConclusionsAOSLO imaging demonstrated variability in the pattern of cone and rod cell loss between two teenage cousins with early AD-CRD, who had similar clinical features and had the identical disease-causing mutation in GUCA1A. This finding suggests that a mutation in GUCA1A does not lead to the same degree of AD-CRD in all patients. Modifying factors may mitigate or augment disease severity, leading to different retinal cellular phenotypes.
Outcomes following polypectomy for malignant colorectal polyps are similar to those following surgery in the general population
Authors: Lopez Anthony , Bouvier Anne-Marie , Jooste Valérie , Cottet Vanessa , Romain Gaëlle , Faivre Jean , Manfredi Sylvain , Lepage Come 
Published: October 2017

ObjectivePopulation-based studies on colorectal malignant polyps (MPs) are scarce. The aim of this study was to describe time trends in the incidence of colorectal MPs before and after the introduction of a colorectal mass-screening programmein 2003 and to assess outcomes (survival and recurrence) after endoscopic or surgical resection in patients with MPs.DesignWe included 411 patients with MPs diagnosed between 1982 and 2011 in a well-defined population. Age-standardised incidence rates were calculated. Univariate and multivariate 5-year recurrence and net survival analyses were performed according to gross morphology.ResultsAge-standardised incidence of MPs in patients aged 50–74 years doubled from 5.4 in 1982–2002 to 10.9 per 100 000 in 2003–2011. Pedunculated MPs were more frequently resected endoscopically (38.2%) than were sessile MPs (19.1%; p<0.001). For patients with pedunculated MPs and a pathological margin ≥1 mm, the 5 -year cumulative recurrence rate did not differ significantly between surgical and endoscopic resection (8.2% and 2.4%, respectively). For patients with sessile MPs, it was 3.0% after first-line or second-line surgical resection, 8.6% after endoscopic resection and 17.9% after transanal resection (p=0.016). The recurrence rate decreased dramatically for patients with sessile MPs from 11.3% (1982–2002) to 1.2% (2003–2009) (p=0.010) and remained stable for pedunculated MPs at 4.6% and 6.7%, respectively. Five-year net survival was 81.0% when pathological margins were <1 mm and 95.6% when ≥1 mm (p=0.024).ConclusionOutcomes following polypectomy in patients with a pathological margin ≥1 mm are similar to those following surgery in the general population. Endoscopic resection needs to be completed by surgery if pathological margins are less than 1 mm.
Adipose tissue macrophages induce hepatic neutrophil recruitment and macrophage accumulation in mice
Authors: Bijnen Mitchell , Josefs Tatjana , Cuijpers Ilona , Maalsen Constantijn J , van de Gaar José , Vroomen Maria , Wijnands Erwin , Rensen Sander S , Greve Jan Willem M , Hofker Marten H , Biessen Erik A L , Stehouwer Coen D A , Schalkwijk Casper G , Wouters Kristiaan 
Published: October 2017

ObjectiveObesity is a risk factor for non-alcoholic steatohepatitis (NASH). This risk has been attributed to visceral adipose tissue (vAT) expansion associated with increased proinflammatory mediators. Accumulation of CD11c+ proinflammatory adipose tissue macrophages (ATM) is an important driver of vAT inflammation. We investigated the role of ATMs in hepatic inflammation during NASH development.DesignvAT isolated from lean, obese or ATM-depleted (using clodronate liposomes) obese mice was transplanted to lean ldlr-/- acceptor mice. Systemic and hepatic inflammation was assessed either after 2 weeks on standard chow or after 8 weeks on high cholesterol diet (HCD) to induce NASH.ResultsTransplanting donor vAT from obese mice increased HCD-induced hepatic macrophage content compared with lean-transplanted mice, worsening liver damage. ATM depletion prior to vAT transplantation reduced this increased hepatic macrophage accumulation. On chow, vAT transplantation induced a more pronounced increase in circulating and hepatic neutrophil numbers in obese-transplanted than lean-transplanted mice, while ATM depletion prior to vAT transplantation reversed this effect. Microarray analysis of fluorescence-activated cell sorting of CD11c+ and CD11c− macrophages isolated from donor adipose tissue showed that obesity resulted in enhanced expression of neutrophil chemotaxis genes specifically in CD11c+ ATMs. Involvement of the neutrophil chemotaxis proteins, CXCL14 and CXCL16, was confirmed by culturing vAT. In humans, CD11c expression in vAT of obese individuals correlated with vAT expression of neutrophil chemotactic genes and with hepatic expression of neutrophil and macrophage marker genes.ConclusionATMs from obese vAT induce hepatic macrophage accumulation during NASH development, possibly by enhancing neutrophil recruitment.
Assessment of the incorporation of CNV surveillance into gene panel next-generation sequencing testing for inherited retinal diseases
Authors: Ellingford Jamie M , Horn Bradley , Campbell Christopher , Arno Gavin , Barton Stephanie , Tate Catriona , Bhaskar Sanjeev , Sergouniotis Panagiotis I , Taylor Rachel L , Carss Keren J , Raymond Lucy F L , Michaelides Michel , Ramsden Simon C , Webster Andrew R , Black Graeme C M 
Published: October 2017

BackgroundDiagnostic use of gene panel next-generation sequencing (NGS) techniques is commonplace for individuals with inherited retinal dystrophies (IRDs), a highly genetically heterogeneous group of disorders. However, these techniques have often failed to capture the complete spectrum of genomic variation causing IRD, including CNVs. This study assessed the applicability of introducing CNV surveillance into first-tier diagnostic gene panel NGS services for IRD.MethodsThree read-depth algorithms were applied to gene panel NGS data sets for 550 referred individuals, and informatics strategies used for quality assurance and CNV filtering. CNV events were confirmed and reported to referring clinicians through an accredited diagnostic laboratory.ResultsWe confirmed the presence of 33 deletions and 11 duplications, determining these findings to contribute to the confirmed or provisional molecular diagnosis of IRD for 25 individuals. We show that at least 7% of individuals referred for diagnostic testing for IRD have a CNV within genes relevant to their clinical diagnosis, and determined a positive predictive value of 79% for the employed CNV filtering techniques.ConclusionIncorporation of CNV analysis increases diagnostic yield of gene panel NGS diagnostic tests for IRD, increases clarity in diagnostic reporting and expands the spectrum of known disease-causing mutations.
The number of subtrees of trees with given diameter
Authors: Chen Zichong 
Published: October 2017

Let [Formula: see text] be a tree of given order [Formula: see text] with diameter [Formula: see text] and [Formula: see text] the number of subtrees of [Formula: see text]. In this paper, we show that: (1) [Formula: see text] and the equality holds if and only if [Formula: see text]; (2) If [Formula: see text] and [Formula: see text], then [Formula: see text] and the equality holds if and only if [Formula: see text], where [Formula: see text] (mod 3) with [Formula: see text], and [Formula: see text] (mod 3) with [Formula: see text]; (3) If [Formula: see text], [Formula: see text] and [Formula: see text] (mod [Formula: see text]) for [Formula: see text] with [Formula: see text], then [Formula: see text] if [Formula: see text], [Formula: see text] if [Formula: see text], and the equalities hold if and only if [Formula: see text].
Inside the Walled Garden
Authors: Sen Rijurekha , Ahmad Sohaib , Phokeer Amreesh , Farooq Zaid Ahmed , Qazi Ihsan Ayyub , Choffnes David , Gummadi Krishna P. 
Published: October 2017

Free Basics is a Facebook initiative to provide zero-rated web services in developing countries. The program has grown rapidly to 60+ countries in the past two years. But it has also seen strong opposition from Internet activists and has been banned in some countries like India. Facebook highlights the societal benefits of providing low-income populations with free Internet access, while detractors point to concerns about privacy and network neutrality.
In this paper, we provide the first independent analysis of such claims regarding the Free Basics service, using both the perspective of a Free Basics service provider and of web clients visiting the service via cellular phones providing access to Free Basics in Pakistan and South Africa.
Specifically, with control of both endpoints, we not only provide a more detailed view of how the Free Basics service is architected, but also can isolate the likely causes of network performance impairments. Our analysis reveals that Free Basics services experience 4 to 12 times worse network performance than their paid counterparts. We isolate the root causes using factors such as network path inflation and throttling policies by Facebook and telecom service providers.
The Free Basics service and its restrictions are designed with assumptions about users' device capabilities (e.g., lack of JavaScript support). To evaluate such assumptions, we infer the types of mobile devices that generated 47K unique visitors to our Free Basics services between Sep 2016 and Jan 2017. We find that there are large numbers of requests from constrained WAP browsers, but also large fractions of high-capability mobile phones that send Free Basics requests.
We discuss the implications of our observations, with the hope to aid more informed debates on such telecom policies.