bluuebunny/crossref_metadata_2025 huggingface dataset:
Insects and incest: Sib‐mating tolerance in natural populations of a parasitoid wasp
Authors: Collet Marie , Amat Isabelle , Sauzet Sandrine , Auguste Alexandra , Fauvergue Xavier , Mouton Laurence , Desouhant Emmanuel
Published: December 2019

Sib‐mating avoidance is a pervasive behaviour that is expected to evolve in species subject to inbreeding depression. Although laboratory studies provide elegant demonstrations, small‐scaled bioassays minimize the costs of mate finding and choice, and thus may produce spurious findings. We therefore combined laboratory experiments with field observations to examine the existence of inbreeding avoidance using the parasitoid wasp Venturia canescens. In the laboratory, our approach consisted of mate‐choice experiments to assess kin discrimination in population cages with competitive interactions. A higher mating probability after sib rejections suggested that females could discriminate their sibs; however, in contrast to previous findings, sib‐mating avoidance was not observed. To compare our laboratory results to field data, we captured 241 individuals from two populations. Females laid eggs in the lab, and 226 daughters were obtained. All individuals were genotyped at 18 microsatellite loci, which allowed inference of the genotype of each female's mate and subsequently the relatedness within each mating pair. We found that the observed rate of sib‐mating did not differ from the probability that sibs encountered one another at random in the field, which is consistent with an absence of sib‐mating avoidance. In addition, we detected a weak but significant male‐biased dispersal, which could reduce encounters between sibs. We also found weak fitness costs associated with sib‐mating. As such, the sex‐biased dispersal that we found is probably sufficient to mitigate these costs. These results imply that kin discrimination has probably evolved for purposes other than mate choice, such as superparasitism avoidance.
Theories and myths in medical education: What is valued and who is served?
Authors: Brown James , Nestel Debra
Published: December 2019

More than explanatory frameworks, Brown and Nestel argue that myths and theories create shared narratives that sustain particular values and political agendas. Understanding this, helps us know what values we prioritise.
Circumferential pulmonary vein antrum ablation for the treatment of paroxysmal atrial fibrillation: A randomized controlled trial
Authors: Xu Qiang , Ju Weizhu , Xiao Fangyi , Yang Bing , Chen Hongwu , Yang Gang , Zhang Fengxiang , Gu Kai , Li Mingfang , Wang Daowu , Chen Minglong
Published: December 2019

Background

It remains unclear whether the curative result of paroxysmal atrial fibrillation (PAF) is a result of pulmonary vein (PV) isolation, PV antrum modification (PVAM), or both. We hypothesized that sufficient antrum modification (PVAM) is as important as PV isolation (PVI) for atrial fibrillation (AF) control and that PVAM can be evaluated by quantified lesion deployment using a force‐sensing catheter.

Methods and Results

Patients of symptomatic PAF were randomly assigned 2:1 into a PVAM group or a circumferential PV isolation (CPVI) group. In the PVAM group, circumferential quantitative ablation evaluated by automatical VisiTag module was performed. In the CPVI group, conventional circumferential ablation was performed to achieve the end point of all‐PV isolation. In total, 180 patients with PAF were enrolled and randomly assigned to either the PVAM group (n = 120) or the CPVI group (n = 60). A total of 179 patients successfully underwent ablation. In the PVAM group, 68 patients achieved all PVI (PVAM‐PVI), while 51 did not (PVAM‐non‐PVI). At 18 months, there was no significant difference in the maintenance of sinus rhythm between the PVAM and CPVI groups (84.9 vs 79.7%, P = .382). The PVAM‐PVI subgroup demonstrated a higher arrhythmia‐free survival compared with the PVAM‐non‐PVI subgroup (92.6 vs 74.5%, P = .006) and the CPVI group (92.6 vs 79.7%, P = .036).

Conclusions

The trial shows that sufficient force‐sensing guided PVAM can result in satisfying outcomes in PAF patients. Notably, sufficient PVAM with all‐PV isolated will further increase the success rate.
Microbial biogeography and ecology of the mouth and implications for periodontal diseases
Authors: Proctor Diana M. , Shelef Katie M. , Gonzalez Antonio , Davis Clara L. , Dethlefsen Les , Burns Adam R. , Loomer Peter M. , Armitage Gary C. , Ryder Mark I. , Millman Meredith E. , Knight Rob , Holmes Susan P. , Relman David A.
Published: December 2019

In humans, the composition of microbial communities differs among body sites and between habitats within a single site. Patterns of variation in the distribution of organisms across time and space are referred to as “biogeography.” The human oral cavity is a critical observatory for exploring microbial biogeography because it is spatially structured, easily accessible, and its microbiota has been linked to the promotion of both health and disease. The biogeographic features of microbial communities residing in spatially distinct, but ecologically similar, environments on the human body, including the subgingival crevice, have not yet been adequately explored. The purpose of this paper is twofold. First, we seek to provide the dental community with a primer on biogeographic theory, highlighting its relevance to the study of the human oral cavity. We summarize what is known about the biogeographic variation of dental caries and periodontitis and postulate that disease occurrence reflects spatial patterning in the composition and structure of oral microbial communities. Second, we present a number of methods that investigators can use to test specific hypotheses using biogeographic theory. To anchor our discussion, we apply each method to a case study and examine the spatial variation of the human subgingival microbiota in 2 individuals. Our case study suggests that the composition of subgingival communities may conform to an anterior‐to‐posterior gradient within the oral cavity. The gradient appears to be structured by both deterministic and nondeterministic processes, although additional work is needed to confirm these findings. A better understanding of biogeographic patterns and processes will lead to improved efficacy of dental interventions targeting the oral microbiota.
Understanding resolution of inflammation in periodontal diseases: Is chronic inflammatory periodontitis a failure to resolve?
Authors: Van Dyke Thomas E. , Sima Corneliu
Published: December 2019

Periodontitis is an infectious‐inflammatory disease that results from loss of balance between the commensal microbiome and the host response. The hyper‐inflammatory, uncontrolled inflammatory immune lesion promotes tissue damage and impedes effective bacterial clearance. In this review, the relationship between the microbiome and the inflammatory/immune response is explored in the context of a bi‐directional pathogenesis; bacteria induce inflammation and inflammation modifies the growth environment causing shifts in the composition of the microbiome. Resolution of inflammation is an active, receptor‐mediated process induced by specialized pro‐resolving lipid mediators. Inflammatory disease may, therefore, be the result of failure of resolution. Failure to resolve inflammation coupled with resultant microbiome changes is hypothesized to drive development of periodontitis. Re‐establishment of microbiome/host homeostasis by specialized pro‐resolving lipid mediator therapy suggests that microbiome dysbiosis, the host hyperinflammatory phenotype, and periodontitis can be reversed.
Multidisciplinary care for a patient with syndromic craniosynostosis: A case report with 20 years of special care
Authors: Shin Kyungsup , Moreno‐Uribe Lina M. , Allareddy Veerasathpurush , Burton Richard G. , Menezes Arnold H. , Fisher Mark D. , Weber‐Gasparoni Karin , Elangovan Satheesh
Published: December 2019

Aim

The functional and structural complexities accompanying syndromic craniosynostosis make dental care for these patients particularly challenging. We report a case of long‐term care for a syndromic craniosynostosis patient. The objective of this report is to introduce special care guidance and clinical recommendation, so that oral health care providers, as key members of a multidisciplinary care team, can provide optimal diagnosis, treatment, and management for the patient with syndromic craniosynostosis.

Case Report

The patient of this case report had a medical history of syndromic craniosynostosis involving multiple comorbidities. Over the past 20 years, a multidisciplinary care team has successfully treated the patient. Dental and medical procedures that the patient has received include cranial surgeries, prophylactic dental care, caries control, growth hormone therapy, comprehensive orthodontic treatment in conjunction with orthognathic surgeries, and plastic surgery.

Conclusion

Oral health care providers can play essential roles in multidisciplinary care for patients with craniosynostosis by understanding the patients’ unique oral health conditions and dentofacial deformities. To provide optimal oral health care in a multidisciplinary team, clear communication between the members of the care team is crucial.
The myth of the “data‐driven” society: Exploring the interactions of data interfaces, circulations, and abstractions
Authors: Lee Ashlin J. , Cook Peta S.
Published: December 2019

The prominence of data and data technologies in society, such as algorithms, social media, mobile technology, and artificial intelligence, have heralded numerous claims of the revolutionary potential of these systems. From public policy, to business management, to scientific research, a “data‐driven” society is apparently imminent—or currently happening—where “objective” and asocial data systems are believed to be comprehensively improving human life. Through a review of existing sociological literature, in this article, we critically examine the relationship between data and society and propose a new model for understanding these dynamics. “Using the concept of the informatic,” we argue the relationship between data and society can be understood as representing the interaction of several different social trends around data; that of data interfaces (that connect individuals to digital contexts), data circulation (trends in the movement and storage of data), and data abstraction (data manipulation practices). Data and data technologies are founded to be entwined and embedded in numerous social relationships, and while not all are fair and equitable relationships, there is ample evidence of the deeply social nature of data across many streams of social life. Our three‐part informatic framework allows these complex relationships to be understood in the social dynamic through which they are witnessed and experienced.
Reassessment of the status of Lymantria albescens and Lymantria postalba (Lepidoptera: Erebidae: Lymantriinae) as distinct ‘Asian gypsy moth’ species, using both mitochondrial and nuclear sequence data
Authors: Djoumad Abdelmadjid , Nisole Audrey , Stewart Don , Holden Dave , Zahiri Reza , Inoue Maki N. , Martemyanov Viatcheslav V. , Levesque Roger C. , Hamelin Richard C. , Cusson Michel
Published: December 2019

For regulatory purposes, the name ‘Asian gypsy moth’ refers to a group of closely related Asian Lymantria species and subspecies whose female moths display flight capability, a trait believed to confer enhanced invasiveness relative to the European gypsy moth, Lymantria dispar dispar, whose females are flightless. Lymantria albescens and Lymantria postalba are Asian gypsy moths occurring in the southern Ryukyu Islands and in the northern Ryukyu and adjacent Kyushu and Shikoku Islands of Japan, respectively. Although once considered subspecies of L. dispar, their status as distinct species, relative to the latter, is now well established. While postalba was subsequently considered a subspecies of L. albescens, largely on the basis of differences in forewing ground colour in males, both taxa were later given distinct species status by Pogue & Schaefer (2007) following their revision of the genus Lymantria. Here, we re‐examined the validity of this revised status through the sequencing of a large portion of the mitochondrial genome (c. 60%) and multiple nuclear marker genes [elongation factor 1‐alpha (Ef‐1α), wingless (Wgl), internal transcribed spacer 2 (ITS‐2), ribosomal protein S5 (RpS5)] in representative specimens of both taxa and other Lymantria species, including L. monacha, L. xylina, L. mathura and members of the L. dispar + L. umbrosa clade. A comparison of the number of substitutions in these genomic regions among the taxa we considered showed lower or equivalent variation between L. albescens and L. postalba compared with subspecies of L. dispar, for mitochondrial and nuclear sequences, respectively. This finding was reflected in the maximum likelihood trees generated independently for mitochondrial and nuclear data, where L. albescens and L. postalba formed, in both analyses, a short‐branch sister clade basal to the L. dispar + L. umbrosa clade. We further sequenced three markers [cytochrome c oxydase 1 (COI), EF‐1α, Wgl] in multiple L. albescens–L. postalba specimens collected along a south‐to‐north transect across the Ryukyu Arc and observed no clear distinction among the sampled specimens as a function of taxonomic designation. We conclude that L. albescens and L. postalba form a single species, with postalba representing a darker‐winged morph along an apparent south‐to‐north wing colour cline. Accordingly, L. postalba is relegated to synonymy under L. albescens (syn.n.).
Sum of squares of deviations
Authors: Bukac Josef , Sulc Jakub
Published: December 2019

The question is whether or not we or any student are allowed to define a measure of variability in some other way that is not written in textbooks and officially approved. We compare the sum of squares of all deviations against the usual sum of squares of deviations from the mean.
Rhesus D alloimmunization in pregnancy from 1996 to 2015 in Iceland: a nation‐wide population study prior to routine antenatal anti‐D prophylaxis
Authors: Gudlaugsson Brynjar , Hjartardottir Hulda , Svansdottir Gudrun , Gudmundsdottir Gudny , Kjartansson Sveinn , Jonsson Thorbjorn , Gudmundsson Sveinn , Halldorsdottir Anna M.
Published: December 2019

BACKGROUND

Rhesus D (RhD) incompatibility is still the most important cause of hemolytic disease of the fetus and newborn (HDFN) worldwide. The aim of this study was to investigate the incidence, causes, and consequences of anti‐D alloimmunizations in pregnancy in Iceland, prior to implementation of targeted routine antenatal anti‐D prophylaxis (RAADP) in 2018.

STUDY DESIGN AND METHODS

This was a nation‐wide cohort study of 130 pregnancies affected by RhD alloimmunization in Iceland in the period from 1996 through 2015. Data were collected from transfusion medicine databases, medical records, and the Icelandic Medical Birth Register.

RESULTS

Of 130 RhD alloimmunizations, 80 cases (61.5%) represented new RhD immunization in the current pregnancy. Sensitization was discovered in the third trimester in 41 (51.3%) and occurred in the first pregnancy in 14 cases (17.5%). The most likely causative immunization event was the index pregnancy for 45 (56.25%), a previous pregnancy/birth for 26 (32.5%), abortion for 3 (3.75%), and unknown for 6 women (7.5%). Higher anti‐D titers were associated with shorter gestational length, cesarean sections, positive direct antiglobulin test (DAT), and severe HDFN. Intrauterine transfusion (IUT) was performed in five pregnancies (3.8%), and 35 of 132 (26.5%) live‐born neonates received treatment for HDFN; 32 received phototherapy (24.2%), 13 exchange transfusion (9.8%), and seven simple blood transfusion (5.3%).

CONCLUSION

In about half of cases, RhD alloimmunization was caused by the index pregnancy and discovered in the third trimester. Thus, the newly implemented RAADP protocol should be effective in reducing the incidence of RhD immunization in Iceland in the future.
Belyi’s theorem in characteristic two
Authors: Sugiyama Yusuke , Yasuda Seidai
Published: December 2019

We prove an analogue of Belyi’s theorem in characteristic two. Our proof consists of the following three steps. We first introduce a new notion called pseudo-tameness for morphisms between curves over an algebraically closed field of characteristic two. Secondly, we prove the existence of a ‘pseudo-tame’ rational function by showing the vanishing of an obstruction class. Finally, we construct a tamely ramified rational function from the ‘pseudo-tame’ rational function.
Introduction to Power Boilers
Authors: Ortman Ed , Vattappilly Jay
Published: December 2019

Section I of the ASME Boiler and Pressure Vessel Code provides rules for the construction of power boilers. This chapter provides an overview of the requirements of Section I and explains how they are applied and enforced. The discussion begins with an outline of the history, philosophy, and scope of Section I, how the ASME Code works, and how it is organized. The chapter then addresses the distinction between boiler proper piping and boiler external piping, and describes how and where Section I is enforced. This is followed by a discussion on the fundamentals of Section I construction. The fundamentals include permitted materials, design, fabrication, welding and postweld heat treatment, nondestructive examination, hydrostatic testing, third-party inspection, and certification by stamping and the use of data reports. The chapter ends by highlighting some of the items which may be included in a future publication of Section I. A few of these include changes to the requirements of pressure testing of replacement parts; changes to the requirements for marking of plate material used for shells, furnace sheets, and heads; and inclusion of corrosion allowance application criteria.

History

Martin D. Bernstein was the originator of this chapter for the first edition. Lloyd W. Yoder updated the chapter for the second edition. John R. MacKay updated the chapter for both the third and fourth editions. Ed Ortman and Jay Vattappilly updated this chapter for the fifth edition. Ed Ortman updated this chapter for the current online edition.
Nonmetallic Pressure Piping System Components
Authors: Rowley C. Wesley , Musto Thomas M.
Published: December 2019

This chapter discusses the current and future nonmetallic construction codes and standards using nonmetallic plastic polymers. It is divided into four parts. Part A provides an overview of the major nonmetallic materials used in structural applications, namely, thermoplastic materials, thermoset plastic materials, and graphite materials. It describes the importance of a design specification as well as its recommended contents and major aspects. Part A also provides information on two extensively utilized thermoplastic jointing techniques: butt fusion and electro-fusion. Part B and C cover NM-1 and NM-2 Standards, which prescribe requirements for the design, materials, fabrication, erection, inspections, examination, and testing of thermoplastic piping systems and glass-fiber-reinforced thermosetting-plastic piping systems, respectively. Included within the scope of the NM-1 Standard is thermoplastic piping which interconnects pieces or stages within a packaged equipment assembly. The contents and coverage of the NM-2 Standard address pipe and piping components that are produced as standard products, as well as custom products that are designed for a specific application. Fiberglass-reinforced plastic pipe and piping components manufactured by contact molding, centrifugal casting, filament winding, and other methods are covered. The organization of the NM-3 Standard, addressed in Part D, is modeled on the ASME Boiler and Pressure Vessel Code, Section II – Materials. ASME NM-3 addresses material specifications and material properties for both thermoplastic and thermoset plastic with glass reinforcing fibers. The NM-1 and NM-2 Standards reference NM-3 Standard for applicable material specifications and material physical and engineering property data.

History

Some of the material in this chapter had been originally covered in Chapter 3.6 in the Fourth Edition of the Companion Guide but consistent with the current activity of the ASME Code Committees it was considered appropriate by the authors to cover the efforts of the committee in a separate chapter. The current online edition was updated by C. Wesley Rowley and Thomas M. Musto
Nuclear Valves
Authors: Jolly Guy A.
Published: December 2019

This chapter describes how the ASME Boiler and Pressure Vessel Code requirements are implemented for safety-related nuclear valves. It explains the relevancy of the ASME Code requirements for safety-related nuclear valves using the latest issue of the Code. The chapter discusses the role of system and component design engineers, as well as the integrity of the Manufacturer. It provides a historical perspective for the Code rules, cross-referencing other Subsections of the Code. The chapter states that the Owner’s responsibilities for system design play an important part in establishing the rules applicable to the Design Specification for each safety-related valve. It also covers the operational and qualification requirements for the procurement of these items from the Manufacturer. The chapter discusses these items for different service conditions with the aid of schematics and references. It then provides details of the ASME B16.34 historical development and provides the current reference dimensional standards from the 2013 and 2015 editions of the Code for use in the construction of “N” stamped valves based on the Code’s B16.34 reference. A list of widely used Valve Standards referenced in ASME B31 Piping Codes is also presented. The coverage on pressure-relief valves includes details on activity underway at Section III to clarify requirements related to pilot-operated and power-actuated pressure relief valves. It also includes details relevant to QME-1 relating to qualification testing required for active valves used in nuclear power plants.

History

Late Douglas B. Nickerson was the original author of this chapter. Marcus N. Bressler updated the second edition and third editions. Guy A. Jolly, updated this chapter specific to valves for 4th edition and 5th editions. The current online edition was updated by Jason Lambin and the ASME Working Group on Valves.
Code for Concrete Containments
Authors: Eberhardt Arthur C. , Jones Christopher A. , Smith Clayton T. , Jovall Ola
Published: December 2019

This chapter describes the bases and provisions of the ASME Boiler and Pressure Vessel Code for Concrete Containments. It describes the concrete containment general environment, types of existing containments, future containment configurations, and background development including the regulatory bases of concrete containment construction code requirements. The chapter addresses reinforced-concrete containment behavior under internal pressure and temperatures of up to about 100°C. The discussion presented includes a comparison between prestressed and deformed-bar concrete reinforcements, the effects of elevated temperature on concrete, and the effect of radial and tangential shear in containment shells. It explains the analysis, design, and testing of concrete containment structures and provides information on the organization of the Concrete Containment Design Code contained in the Code Section III, Division 2, Subsection CC. The chapter summarizes the following requirements for concrete containments: general and specific construction or placement requirements for concrete, including the fabrication and placing requirements for steel reinforcement systems and the fabrication and welding requirements for liners; requirements for nondestructive examinations, procedure qualifications and evaluations; requirements for qualification and certification of nondestructive personnel; and general requirements for containment structural integrity test. The major areas to be considered in the future revisions of the Code are also highlighted in this chapter.on and certification of nondestructive personnel; and general requirements for containment structural integrity test. The major areas to be considered in the future revisions of the Code are also highlighted in this chapter.

History

John D. Stevenson was the original author of this chapter and updated it for the second edition. The third edition was updated by Joseph F. Artuso, Hansraj Ashar and Barry Scott. The fourth edition was updated by Arthur Eberhardt, Michael Hessheimer, Ola Jovall and Clayton Smith. The fifth edition was updated by Arthur C. Eberhardt, Clayton T. Smith, Ola Jovall and Christopher A. Jones. The current online edition was updated by Arthur C. Eberhardt and Christopher A. Jones.
Section VII—Recommended Guidelines for the Care of Power Boilers
Authors: Mollitor Barrie , Lowry William L.
Published: December 2019

This chapter covers ASME Boiler and Pressure Vessel Code Section VII, which presents guidelines for safe, reliable operation as well as avoiding unsafe conditions in power boilers. The guidelines apply to power boilers that produce steam for external use at a pressure exceeding 15 psig from the application of heat, which come from the combustion of fuels, from various hot waste gases, or from the application of electrical energy. The bulk of this chapter is devoted to the discussion on Subsection 1 of Section VII, which contains information about industrial, gas- or oil-fired, watertube boilers. Subsection 1 introduces the fundamentals of watertube boilers, the principles of boiler operation, the associated auxiliaries, and appurtenances required by ASME Code Section I. It also introduces the necessary instrumentation, the examinations to be performed by boiler operators and staff, and the requirements for repairs, alterations, and maintenance. Subsection 2 presents an overview of the control of chemical conditions within steam boilers. It provides information relating to internal cleaning and laying-up of boilers, internal corrosion due to deposits within boiler tubes, and corrosion cracking. The discussion covers the types of water treatment problems within boilers, and how each problem may be recognized and corrected so as to prevent boiler failures. Subsection 3 deals with firetube, electric, and utility boilers and Subsection 4 includes all information pertaining to coal-fired and other solid-fuel-fired boilers. Articles in Subsection 4 describe the types of ash and their removal and contain short generic lists of maintenance checks for these boilers. Subsection 5 is a glossary of the terms that may be used when referring to a power boiler and its associated facilities. Section VII is a practical boiler book, a good review for experienced personnel and a good teaching aid for less-experienced personnel.

History

The original author of this chapter was Edmund W. K. Chang. The second and third editions were updated by Edmund W. K. Chang and Geoffrey M. Halley.

The fourth edition was updated by James T. Pillow. The fifth edition was completely revised by William L. Lowry. Barrie Mollitor updated this chapter for the current online edition.
Safety of Personnel Using Quick-Actuating Closures on Pressure Vessels and Associated Litigation Issues
Authors: Reedy Roger F.
Published: December 2019

Quick-actuating closures have been used on ASME pressure vessels for more than 50 years. This chapter was written because of the number of lawsuits filed against manufacturers of quick-actuating closures even though these were operated by the owners of pressure vessels for 20, even 30 and more, years without any serious accidents. This is because, in order to bring forth litigation, lawyers would skillfully take words in the ASME Boiler & Pressure Vessel Code completely out of context. Or, some attorneys for the injured party may misinterpret the Code rules to accuse the manufacturer of not having complied with the Code when the closure was made. So, based on experience, the author warns the writers of the ASME Code to assure that the rules are clear, concise, and understandable to the common man. He hopes that the rules in Section VIII, Division 1 will incorporate many of the suggestions mentioned in this chapter. To understand the current Code requirements for quick-actuating closures, the author identifies each of the changes made to the Code rules in Section VIII, Division 1, from 1952 Edition to the 2007 Edition of the ASME Code. The chapter includes an Appendix that provides guidance in the form of recommendations for the installation, operation, and maintenance of quick-actuating closures. This guidance is primarily for the use of the Owner and the User. The safety of the quick-actuating closure is the responsibility of the user. This includes the requirement for the user to provide training for all operating personnel, follow safety procedures, periodically inspect the closure, provide scheduled maintenance, and have all necessary repairs made in a timely fashion. The chapter also contains guidance for use by the designer. The chapter concludes with a list of suggested future changes in the Code for quick-actuating closures on pressure vessels.

History

Roger Reedy is the original author of this chapter introduced in the third edition and has updated it for the fourth, fifth and the current online edition.
Section XI Flaw Acceptance Criteria and Evaluation Using Code Procedures
Authors: Cipolla Russell C.
Published: December 2019

For the sixth edition, this chapter has been updated with revised Code requirements and Code Cases from the 2017 Code and 2019 Code Editions. The important areas of revised requirements and procedures include flaw proximity rules in IWA-3300, change in the yield strength limits from 50 ksi to 90 ksi for selected grades of SA-508 and SA-533, addition of stress intensity factor equations for circumferential OD surface flaws in Appendix A, A-3000, revised procedures for pipe flaw evaluation in Appendix C, C-4000 and C-5300, and an updated glossary terminology/definitions. Several new and revised Code Cases are also discussed to include N-513-5 (temporary acceptance of flaws in moderate energy piping systems), N-705-1 (temporary acceptance of flaws in moderate energy vessels and tanks), N-806-1 (evaluation of wall loss in buried pipe), N-848-1 (proximity rules for quasi-laminar flaws), N-869 (extension of N-513 to higher pressures for Class 2 and 3 piping systems), N-877 (characterization of multiple subsurface radially oriented planar flaws), N-889 (new reference curves for irradiated-assisted stress corrosion cracking growth for austenitic stainless steels), N-899 (weld residual stress reference curves for dissimilar metal welds), and N-890 (materials exempted from Appendix G, G-2110(b) requirements). It is important to note that additional proposal changes are being developed by the committees, some of which are discussed in 30.11.

History

Arthur F. Deardorff was the original author of this chapter that was updated by Mr. Deardorff in the second edition. For the third through fifth editions, Russell C. Cipolla revised the entire chapter although retaining certain portions of the previous text, equations, tables, and figures. For the current online edition, Mr. Cipolla has updated using 2017 and 2019 Editions, and additional information as appropriate.
IWE and IWL
Authors: Staffiera Jim E.
Published: December 2019

This chapter addresses ASME Code Section XI, Subsections IWE and IWL, for nuclear power plant containments. Subsection IWE provides requirements for preservice and inservice examination/inspection, repair/replacement (R/R) activities, and testing of Class MC (metal containment) pressure-retaining components and their integral attachments and R/R activities. It also provides requirements for testing of Class CC (concrete containment) pressure-retaining components and their integral attachments for boiling water reactors (BWRs) and pressurized water reactors (PWRs). Similarly, Subsection IWL provides requirements for preservice and inservice examination/inspection, R/R activities, and testing of the reinforced concrete and post-tensioning systems of Class CC components for BWRs and PWRs. Together with Subsection IWA, a comprehensive basis is provided for ensuring the continued structural and leak-tight integrity of containments in nuclear power plants. The chapter includes a brief history of the development of ASME Code requirements, the latest information on the U.S. Nuclear Regulatory Commission regulatory review and incorporation of recent ASME Code Editions and Addenda, and current listings of U.S. ‘construction-complete’ commercial nuclear power plants and their containment types and operating status. A summary of recent nuclear industry developments in advanced plant designs and a discussion of the as-yet-unrealized ‘U.S. nuclear renaissance’ are also presented, along with information on the global demand for energy and the current status of commercial nuclear power around the world. Lastly, the current Subsection IWE and IWL Commentaries, as approved and maintained by the ASME Working Group on Containment, are included.
Fatigue Crack Growth, Fatigue, and Stress Corrosion Crack Growth: Section XI Evaluation
Authors: Bamford Warren H.
Published: December 2019

Fatigue has often been described as the most common cause of failure in engineering structures, and designers of pressure vessels and piping have incorporated fatigue considerations into design requirements since the first edition of Section III in 1963. The development of this technology and its application in Section III are discussed in Chapter 39 of the third edition of this publication. Its application in Section XI is discussed in Section 32.3 of this chapter.

With the advancement of the state of the art, the ability to recognize how the growth and size of a crack can lead to failure has been enhanced. This technology has been a key aspect of the Section XI flaw evaluation procedures since the 1974 edition was published and will be discussed thoroughly herein.

Further advancements in the state-of-the-art in fracture evaluation resulted in the introduction of models for stress corrosion cracking into Section XI in 2001, and since that time additional models have been added and more are planned. This addition gives Section XI flaw evaluations a complete treatment of all the potential modes of cracking that can occur in components, and details will be provided in Section 32.2.

Since additional crack growth data, for both fatigue and stress corrosion cracking, is periodically made available on a regular basis from additional research testing, the models contained in Section XI are regularly reviewed and updated to ensure their applicability, accuracy, and reflection of the latest known material behaviors. This improved knowledge may lead to more conservative models for crack growth over time. To accommodate such situations, Section XI has adopted an approach to conservatively account for potential increases in crack growth predictions with augmented examinations. The rules of IWB-3600 require that augmented (additional) examinations must be performed at an accelerated pace for situations where a flaw indication was accepted by analytical evaluation. This rule also protects against NDE uncertainties at the location of interest.

The nomenclature used here will be identical to that used in Section XI; any nomenclature that is not present in Section XI will be explained as it appears.

This chapter has been updated using the 2019 Code edition.

History

Warren H. Bamford is the original author of this chapter and has since revised it for all of the subsequent editions including the current online edition.
ASME Piping Code: B31.1, Power Piping
Authors: Meyer Jimmy E. , Vilminot Kristi A. , Frey Joe
Published: December 2019

This chapter covers the ASME B31.1 Power Piping Code and provides additional insight into the proper use of the Code. The chapter intends to supplement and provide additional insight to the proper use of the Code. It begins with a discussion of the conditions or considerations for the design of piping systems; the basis of the allowable stresses, quality factors, etc. to be used for the design of piping systems; and the requirements for pressure design of piping components. The chapter briefly addresses various piping components or types of piping joints which might be limited to nonhazardous or nonflammable fluids, size limitation, pressure, and temperature limits. It also addresses the requirements for designing power piping systems subject to thermal expansion, contraction, or other displacement stress producing loads. The chapter then provides information on the factors to be considered during the design of pipe supports and those piping systems typically found in power generating facilities. It presents some examples of how the piping codes are interrelated for some common carbon steel and stainless steel Pressure Rating/Dimensional Standards, Material Forming Standards, and Material Grades. The chapter lists the acceptable standards for Code construction such as ASME, API, AWWA, ASTM, etc. It then addresses the requirements for fabrication, assembly, inspection, examination, testing, and maintenance of piping systems. A number of appendices are included in the Code. The Mandatory Appendices contain information on allowable stress, thermal expansion data, moduli of elasticity, stress intensification factors and rules for nonmetallic pipes to name a few. The Nonmandatory Appendices include information on safety valves, corrosion, and operation and maintenance and more.

History

Charles Becht IV was the author of “Chapter 16” titled “B31.1 Power Piping” for the original, second and third editions. Chapter 17 of the third edition was revised in its entirety and renumbered as Chapter 36 in the fourth edition. The fifth edition was authored by Jimmy E. Meyer and Joe Frey. The current online edition has been updated by Jimmy E. Meyer and Kristi A. Vilminot.
ASME Piping Codes: B31.3 Process, B31.5 Refrigeration, B31.9 Building Services and ASME Standards for Piping: B31E Seismic Design, B31J Stress I-Factors, B31T Toughness Requirements
Authors: Meyer Jimmy E. , Vilminot Kristi A.
Published: December 2019

The ASME B31.3 Process Piping Code is one of a series of piping codes which cover piping for various industries. This chapter covers the ASME B31.3 Process Piping Code as well as some of the other books in the B31 series: In PART A: B31.3–2014 Process Piping; In PART B: B31.5–2013 Refrigeration Piping and Heat Transfer Components; In PART C: B31.9–2014 Building Services Piping; In PART D: B31E–2008 Standard for the Seismic Design and Retrofit of Above-Ground Piping Systems; In PART E: B31J–2013 Standard Test Methods for Determining Stress Intensification Factors (i-Factors) for Metallic Piping Components; and In PART F: B31T–2010 Standard Toughness Requirements for Piping. After the Introduction, each Code is organized as follows: Scope and Definitions; Design; Materials; Standards for Piping Components; Fabrication, Assembly, and Erection; and Inspection, Examination, and Testing. In addition to dealing with Process Piping Code, Part A gives insight into how the other documents are related and used to supplement the requirements in ASME B31.3. A number of simplified approaches are provided to help the reader understand the general principles associated with the requirements of the Code(s).
A Commentary for Understanding and Applying the Principles of the ASME Boiler and Pressure Vessel Code
Authors: Reedy Roger F.
Published: December 2019

This chapter provides a commentary on the principles of the ASME Boiler and Pressure Vessel Code to help users apply common sense when using the Code. It provides engineers, owners, inspectors, regulatory institutions, and other Code users with a better understanding of the basic principles of the Code. The chapter begins with a discussion on the design factors used by the ASME Committee to determine allowable stress and the requirements for a Design Specification and a Stress Report. It then provides information on the seismic design requirements and describes the use of Service Levels A, B, C, and D to provide increased allowable stresses for upset, emergency, and faulted plant conditions, as appropriate. The chapter emphasizes the need for good engineering judgment by knowledgeable professional engineers. This is essential for understanding which computer output should be used or how the output must be modified. The chapter discusses the revision made in the Foreword to the ASME Code in the 1992 Addenda to specify that engineering dimensions require tolerances and that Code-specified dimensions are based on nominal sizes. A brief note is provided on the identification of the proper allowance for erosion and corrosion caused by service conditions. The chapter also points out concerns with the use of finite element analysis in design activities. Forming operations for pressure vessels and postweld heat treatment of some welded configurations are briefly covered. In addition, the chapter discusses the importance of performance-based quality assurance programs and the use of thermal relief devices to protect pressure vessels or piping against pressure that results from the heat of the fluid contained in the component. Other issues addressed include the evaluation of new hypothetical loads on equipment that has been Code Stamped, and the purpose of hydrostatic testing of pressurized equipment.
Subsection NB—Class 1 Components
Authors: Basavaraju Chakrapani , Lambin Jason
Published: December 2019

This chapter discusses the structural limits in Section III NB and Section VIII Division 2 as related to specific structural failure modes considered applicable to pressure vessel and piping design. The rules and requirements for Section III NB and Section VIII Division 2 are based on the design-by-analysis philosophy addressing specific structural failure modes of structural collapse, rupture, instability, fatigue, and progressive deformation. The chapter begins with a discussion on the interactions between materials, environments, mechanical, and thermal loads as aided by other disciplines since this is critical for every part of every pressure vessel design. It provides a brief history of development of Code analytic tools and discusses the use of elastic 3D finite element analysis (FEA) results and the application of elastic-plastic (EP)-FEA. The chapter then discusses the intent of the primary stress limits in the Code. Consideration is given to the definitions in the Code and the discussion in the Criteria document. The chapter then addresses why the primary-plus-secondary stress intensity range is necessary and shows how to apply it. Two procedures for calculating stress intensity are presented, and the impact of thermal stresses is discussed for definition and application. The chapter also discusses six areas in which the Code presents fundamental procedures and expands on these fundamentals by presenting guidelines for a singular view of acceptable procedures that are consistent with the original intent for Section III and consistent with the current rules. Finally, it comments on the elastic-plastic FEA methods to protect against plastic collapse, to determine protection against local failure, and to assess fatigue and ratchet limits.

History

Tom Ahl was the original author of this chapter for the first edition. Marcus N. Bressler updated this chapter for the second and third editions. Chakrapani Basavaraju updated this chapter for the fourth, fifth and sixth editions. The current online edition has been updated by Chakrapani Basavaraju and Jason Lambin.
Subsection NB, NC, ND-3600 Piping
Authors: Gray Mark A. , Cole Jack R.
Published: December 2019

This chapter provides a commentary on the criteria and basis for requirements of Subsections NB, NC, and ND for Piping. It presents information on the corresponding design processes and design specifications, with pertinent references, tables, and figures. The chapter addresses service limits and loading conditions classified as Levels A, B, C, and D. The Code rules assure that violation of the pressure boundary will not occur if the design specification satisfactorily addresses all issues necessary for Code compliance. This assurance is provided in the following ways: protection against catastrophic failure and protection against initiation and propagation of a crack or propagation of a Section III acceptable flaw through the pressure boundary. The chapter addresses how Section III provides this protection, any variations that exist or that have existed between the piping rules and the design-by-analysis rules, and what items the analyst should be concerned with in satisfying Code requirements. It helps alleviate the confusion regarding the proper application of ANSI B31.7 rules. As the requirements of NB-3600 are discussed, the important areas are compared to those of NB-3200. The chapter also shows that for primary stress protection, NB-3200 and NB-3600 are quite different, but in the secondary and peak stress areas, including fatigue, the basis for the rules is essentially the same although the analytical approach is quite different. It then covers rules for both Class 2 (NC-3600) and Class 3 (ND-3600) piping design. The chapter also explains the importance of a design specification. Finally, it discusses the need for a process of analysis with release of information that needs to be established to provide an orderly flow of information, to assure timely pipe fabrication and support delivery, and to issue stress reports at reasonable times.

History

Donald F. Landers was the original author who updated the chapter for the second and third editions. The fourth edition was revised by Jack R. Cole. The fifth edition was updated by Jack R. Cole and Mark A. Gray are. The current online edition was updated by Mark A. Gray and reviewed by George Z. Tokarski.
Subsection NE—Class MC Components
Authors: Reedy Roger F.
Published: December 2019

This chapter provides a summary of some of the significant requirements of the ASME Code Section III, Subsection NE Class MC vessels, and a commentary on these requirements. It begins with an overview of the scope of Subsection NE and the boundaries of its jurisdiction. The chapter then outlines the general material requirements for Class MC vessels that are specified in Article NE-2000. This is followed by a discussion on material toughness requirements and design and analysis requirements. The chapter provides information on Certified Material Test Reports and on certifications that must be performed by engineers who prepare design and overpressure protection reports. The chapter then describes the rules for the following analyses of containment vessels as defined in Subsection NE: fatigue analysis, buckling analysis, design by analysis, and plastic analysis. An outline of the rules for reinforcement of cone-to-cylinder junctions, overpressure protection, bolted flange connections, and welded connections, is also presented. The closing pages cover the following topics: tolerance requirements for some commonly used shells; fabrication requirements for each weld category as specified in NE-4240; welding procedure qualification; rules for marking, examining, and repairing welds; and nondestructive testing personnel qualification and certification. A number of Code Cases and references regarding the rules of Subsection NE are cited, with cross-references to other Code Sections and Subsections.

History

Kamran Mokhtarian was the original author of this chapter and revised it for the second edition. Roger Reedy updated it for the third through current online edition.