bluuebunny/crossref_metadata_2025 huggingface dataset:
New Expertise on High-Temperature Hydrogen Attack Degraded Samples by TotalEnergies and the French Atomic Energy and Alternative Energy Commission
Authors: Le Nevé Charles , Goti Raphaël , Andrieu Eric , Gillia Olivier , Flament Camille , Chevreux Nicolas
Published: November 2024

Hydrogen is a crucial element in refinery operations and has historically been employed under different conditions, often involving high pressure and elevated temperatures. However, when hydrogen levels surpass 3,5 bar (50Psi) and temperatures exceed 207°C (400F), a potentially catastrophic damage called High-Temperature Hydrogen Attack (HTHA) can occur on ferritic steels. HTHA leads to irreversible damage in steels, posing a significant risk within the Oil & Gas industry. Despite its pervasive impact, HTHA remains inadequately understood, making it a persistent challenge for Oil & Gas industry. In response to the threat posed by HTHA, the TotalEnergies Company undertook research to address this issue. Recognizing the need for comprehensive insights, TotalEnergies collaborated with scientists from the French Atomic Energy and Alternative Energy Commission (CEA) to conduct meticulous evaluations of HTHA damaged samples. These expert assessments were aimed to better understand the intricate processes underlying HTHA degradation, particularly during its early stages. Moreover, the collaborative effort extended to research involving artificial samples, allowing for controlled experimentation and analysis. This approach tries to provide a nuanced understanding of HTHA mechanisms. This paper presents current and ongoing work. Additionally, this paper outlines plausible hypotheses that delve into the intricate interplay of atomic hydrogen within a metal matrix of ferritic steel under HTHA conditions. These hypotheses not only enhance our comprehension of HTHA but also try to open new approaches for advancements in the mitigating risks coming from this formidable challenge of the use of hydrogen.
Biaxial Constraint Effect on Fracture Toughness Evaluation of Reactor Pressure Vessel Under Pressurized Thermal Shock Events
Authors: Shimodaira Masaki , Yamaguchi Yoshihito , Iwata Keiko , Katsuyama Jinya , Chimi Yasuhiro
Published: November 2024

According to the structural integrity assessment method prescribed in Japan Electric Association Code (JEAC) 4206-2016 for reactor pressure vessel (RPV) steel, the fracture toughness (KJc) should be higher than the stress intensity factor at the crack tip to prevent brittle fracture during a pressurized thermal shock (PTS) event. Typically, fracture toughness is measured using the compact tension (C(T)) specimen with a deep crack (a/W = 0.5). The stress intensity factor is calculated by assuming a shallow underclad crack (UCC). Discrepancies in crack depth, the presence of clad, and the loading conditions between the C(T) specimen and the postulated crack in the RPV affect the plastic constraint state, and consequently the evaluation of KJc. This study aimed to quantitatively investigate the conservatism of the fracture toughness tolerance bound specified in JEAC4206-2016. The present paper involves the project of the multiaxial fracture test using the large-scale specimen with a shallow UCC and the result of uniaxial fracture tests using the C(T) specimen and specimens with various crack depths and shapes to establish the reference data. In the multiaxial fracture test, the shape of the specimen and loading conditions were carefully designed to replicate the stress distribution across the RPV thickness during a PTS event. Results from the fracture test and analysis utilizing the C(T) and shallow cracked specimens confirmed that the KJc of the shallow cracked specimen was higher than that of the C(T) specimen. Employing a local approach, the KJc of the cruciform specimen was estimated, considering the effect of plastic constraint. The estimated KJc for the cruciform specimen was substantially higher than the tolerance bound calculated using the methodology prescribed in JEAC4206-2016.
Effects of Temperature and Hydrogen on Fatigue Properties on 304L
Authors: Chochoy Romain , Osmond Pierre , Bertheau Denis , Benoit Guillaume , Guedes Sales Daniella , Girardin Gouenou , Hénaff Gilbert
Published: November 2024

The design of liquid hydrogen tanks requires a thorough understanding of the factors influencing fatigue crack initiation and propagation at cryogenic temperatures in materials used in hydrogen environments. To gain a more precise understanding of the impact of hydrogen on the fatigue properties of austenitic stainless-steel alloys, this study examines its effect on fatigue strength and behaviour at different temperatures. Indeed, low temperatures raises the role of changes in the microstructure in relation with hydrogen embrittlement of these steels. The study concludes that hydrogen affects fatigue strength at ambient temperature. As for the evolution of the ratchetting deformation, no difference was noted between an air and hydrogen environment. These results will allow further steps to compare the effect of external hydrogen (in-situ tests) with that in solution (ex-situ tests).
Characterization of Fatigue Behaviors of Notched 316L DED AM Specimens
Authors: Krentz Tim , Dong Pingsha , Rawls George
Published: November 2024

As additive manufacturing (AM) is rapidly being adopted for cost-effectively fabricating metallic parts for safety-critical components subjected to fatigue loading, one of the major challenges has been on how to address structural significance of spatially distributed geometric discontinuities associated with the metallic AM process. This is particularly the case for directed energy deposition (DED) processes, e.g., in laser- and wire arc-based processes, as found in the previous study reported by the same authors at the same conference last year. Since DED processes have received increasing attention for their ability to produce large volume parts for applications in pressure equipment, this study focuses on achieving a better understanding fatigue behaviors of DED AM specimens containing as-build stress risers that emulate stress gradient effects on fatigue in actual components. This was done through the introduction of printed circular notch test specimens in two configurations, i.e., double edge notched (ENT) specimens and center-notched (CNT) fatigue test specimens. Fatigue testing is performed on these specimens and traction structural stress modeling is then performed for fatigue test correlation. It is found that test data obtained so far show a similar trend represented by the master E-N curve reported in the conference last year. However, the scatter band of the limited DED data so far seems somewhat larger. In addition, the traction structural stress method is shown to be effective in correlating test data from test specimens without and with presence of stress risers, therefore offering an effective tool for extracting fatigue design allowables for cost-effectively deploying DED AM components through design by analysis.
Understanding the Semi-Probabilistic Approaches in Structural Reliability Used to Set Design Reliability Targets for Graphite Components Using ASME BPVC Methods
Authors: Mack Andrea , Hoffman William
Published: November 2024

Graphite is a quasi-brittle material, resulting in random variability in tensile strength distributions. To account for the random variability in strength, HHA-3000 of the ASME BPVC provides two semi-probabilistic methods for qualifying nuclear graphite components in the design stage, the simplified and full assessments. The full and simplified assessments apply statistical methods to engineering-based design problems. This is often referred to as reliability-based design. Reliability-based design (RBD) is a method to develop reliable designs by accounting for uncertainties and result in small chances of failure when also considering safety factors. RBDs provide reliability targets using semi-probabilistic approaches. RBD is implemented in ASME BPVC HHA-3000 for nuclear graphite components, but is not specific to that application.

There has been much confusion around the methods implemented in ASME BPVC HHA-3000 for qualifying nuclear graphite components. To address the confusion, this paper takes a hierarchical approach. First, the general RBD framework is presented. Then, the semi-probabilistic methods and the underlying assumptions implemented in the assessments are presented. The semi-probabilistic methods are separated from the engineering modifications that have been made to the assessments. After building the framework and underlying assumptions, the specific methods in the full and simplified assessments are explained in three steps: inputs, methods, outputs. The methods are applied to an H-451 reflector block. Tensile strength properties for other graphite grades are provided.
Physics Informed Graphite Material Model
Authors: Saitta Michael , Johannes van Zanten Florentius , Baylis Samuel
Published: November 2024

This paper presents X-energy’s physics-informed irradiated graphite material model. The model captures the key physical phenomena resulting in elastic strain, thermal strain, dimensional change strain, and creep strain; all under the effects of varying temperature and irradiation. The equations used are based on those of Bradford and Steer [1] and Davies and Bradford [2], but this prior work is extended in several key ways. First, the equations previously presented as 1D scalar terms are augmented to include the full 3D form of the strains and stresses and inter-directional, orthotropic interactions. This allows for a suitable material model to be developed for the evaluation of 3D structural elements. Second, the equations are extended to account for irradiation at varying temperatures when model parameters are temperature dependent, allowing for the evaluation of variable or transient temperature loading scenarios. The use of this new model is demonstrated by tuning it using historic ATR-2E data. A robust validation is carried out with hundreds of experimental data points to demonstrate the applicability of the model. The result of these developments is a fully-featured graphite material model which can simulate graphite in a wide range of reactor environments and loading conditions which impact complex geometric graphite structures. This mechanistic characterization of radiation, temperature and load-effects could allow for extrapolation of the irradiation tests performed, lessening the number of irradiation tests required to properly characterize the graphite material behavior under irradiated conditions. Future work aims to take advantage of similarities between different grades of isotropic and near-isotropic nuclear graphite to create a model for which model parameters can be fine-tuned between grades.
A Continuation of Best Practices for Tightening Bolted Flange Connections Utilizing a Torque Wrench With an Extension
Authors: Berrios Aidan , Waterland Ben
Published: November 2024

Across the chemical production and transportation industries, leaders are searching for best practices to reduce downtime while providing consistency and repeatability for assembling bolted flanged connections. Unfortunately, not all flanges are easily accessible, and a crowfoot extension is required to reach and tighten fasteners properly. On top of this, little to no guidance on flange assembly best practices involving extension tools has been provided. To address this, the PVP paper PVP2022-83963 [1] outlined the best practices for using a torque wrench with a crowfoot extension. It also addressed some topics unique to torque wrenches that use a crowfoot extension, namely the resultant torque based on the length and angle of the crowfoot extension relative to the torque wrench.

The research presented in [1] was a significant initial step in continuing the knowledge regarding best practices for tightening flanges with a torque wrench with an extension. This paper continues this research to confirm if the data presented in [1] is similar for different conditions, including various extension angles, multiple bolt diameters, and higher torque values. With the data collected for this testing, end-users will further understand the variables affecting the applied torque when using an extension and methods of ensuring the proper torque is applied to each fastener.
Case Study: Tube Plugging Evaluation Using Finite Element Analysis Method for Waste Heat Boiler
Authors: Gu Ming (Forrest) , Pasnik Louis , Pease Derrick , Seipp Trevor G.
Published: November 2024

Multiple tubes had suffered from wall thinning of a reformer transfer line exchanger. Tube plugging was considered to reduce equipment downtime in lieu of the complex repair or replacement process with new replacement tubes. A case study demonstrates how to evaluate the effect of tube plugging for flexible tubesheet shell-side steam-generating heat exchanger designs.

Finite element method was used to calculate the stress of the heat exchanger for the plugged tube scenario. Steady-state temperature profile of the tube and tubesheet was first calculated, and the temperature profiles were used for stress calculation. Stress results were compared to the ASME Section VIII Div. 1 Part UHX allowable load limits [1]. Although Part UHX prescribes the limit of compressive stress for tubes, the buckling failure mode is not explicitly considered. ASME Section VIII Div. 2 Part 5 buckling analysis was performed to determine the minimum tube plugging thickness [2]. The analysis considered the compressive load limit from Part UHX and shell side external pressure, and the results found that the tube plugging was feasible. However, depending on the pattern, plugging tubes could increase the stress for non-plugged tubes and tubesheets. Therefore, evaluation of tube plugging is required to ensure the integrity of the heat exchanger.
Hydrogen Storage Lifecycle Assessment
Authors: Prewitt Thomas , Esmaeely Saba
Published: November 2024

With the increased use of renewable sources of energy, interest has piqued in methods of energy storage. The path of decarbonization will require many different energy storage methods to be successful. Storing energy in hydrogen may be one such method.

There are a large variety of methods to store renewable energy, current paper discusses a scenario, where the energy will be used to create hydrogen gas which can be stored in pipelines and used later. This assessment will assume a set amount (moles) of hydrogen is going to be generated, then used daily. The objective is to determine the relationship between these design parameters and the lifespan of the pipe, and subsequently compare the estimated lifespan.

The fatigue lifespan was assessed utilizing equations from published literature and standards will be used. The fatigue life is determined by considering the amount of hydrogen input and output from the system and its effect on a hypothetically initially-indetectable flaw. Hydrogen service can induce hydrogen embrittlement and accelerate fatigue crack growth making this growth more aggressive than in non-hydrogen service. Various pipe diameters, wall thicknesses, and material grades are investigated to capture a wide range of design possibilities.

The findings of this study contribute valuable insights into the design considerations and economic feasibility of pipelines used for hydrogen storage. The evaluation of fatigue lifespan provides guidance for selecting optimal pipe dimensions and material grades to achieve the desired operational reliability while minimizing the total lifecycle cost of the hydrogen storage system. This knowledge aids in the development of sustainable and economically viable hydrogen infrastructure for future energy applications.
Seismic Risk Assessment of Non-Structural Components in Hazardous Facilities Through a Novel ANN-Based Technique
Authors: Quinci Gianluca , Paolacci Fabrizio , Fragiadakis Michalis
Published: November 2024

Seismic events pose a significant threat to industrial facilities, and the risk assessment of non-structural components (NSCs) within these structures is paramount for ensuring the safety and functionality of critical infrastructure. This paper presents a novel approach utilizing machine learning techniques to enhance the seismic risk assessment of NSCs in industrial facilities. The proposed methodology integrates data from multiple sources, including seismic records, structural characteristics, and NSC vulnerability parameters, to develop predictive models for evaluating the vulnerability and potential damage to non-structural components during seismic events.

The study starts from a dataset generated by using a numerical effective model subjected to a set of natural records. The advantages of using an efficient model that manages to be both reliable and computationally efficient are highlighted in this paper. With this in mind, the steps to be followed to create an efficient numerical model are herein illustrated.

Subsequently, an artificial neural network machine learning algorithm is adopted for training and evaluation. The latter is used for predicting the likelihood of damage to NSCs based on factors such as the intensity and duration of ground motion, the NSC’s location within the structure, and its inherent vulnerability characteristics.

Results are compared with traditional methods. The outcomes indicate the effectiveness of machine learning in improving the accuracy and efficiency of seismic risk assessment for NSCs in industrial plant.

The research contributes to the field of seismic risk assessment by demonstrating the potential of machine learning combined with an efficient numerical model in providing more accurate and timely predictions for the vulnerability of non-structural components, thereby aiding in the development of targeted mitigation strategies and emergency response plans. This paper serves as a foundational step towards a data-driven approach to seismic risk assessment for non-structural industrial components, ultimately reducing the economic and human losses associated with seismic events.
Investigation of Ultimate Behavior of Elbow Pipes by Tensile Loading Tests in the Direction of In-Plane Bending (Part 2)
Authors: Shimazu Ryuya , Sakai Michiya , Ono Yohei
Published: November 2024

Probabilistic risk assessment is useful in considering the safety of nuclear power plants. To recognize the weaknesses of structures, a realistic fragility assessment must be conducted, for which the failure mode must be set appropriately. In this study, tensile loading tests on full-scale elbow pipes were conducted to enrich the knowledge of failure modes of piping systems. The 150A Sch80 and 200A Sch40 elbow pipes made of carbon steel (JIS STPT410S) finally ruptured at the ductility factors of 38.28 and 34.75, respectively. Aiming at a realistic fragility assessment of ductile ruptures, analytical models that precisely predict the test results were investigated. This study considered that the method of determining the occurrence of ductile failure by comparing the true strain of the rupture and the equivalent plastic strain of the analysis was not appropriate. The low cycle fatigue life prediction model as the summation of the ductile and cyclic damage was considered possible to determine the ductile rupture of elbow pipes. To apply the criteria based on the ratio of the true elongation of rupture and the stress triaxiality squared to the ductile rupture of elbow pipes, the data regarding the material and shape had to be expanded.
Improving Fastening Methods for Threaded Cast-Iron Fittings
Authors: Rivas Allen J. , Elfass Sherif A.
Published: November 2024

Threaded cast-iron fittings find application in a wide array of uses, from residential and commercial natural gas distribution lines to fire-suppression systems. Despite their extensive use, industry standards for mechanically tightening cast-iron pipe-fitting assemblies remain undefined in crucial codes such as the IAPMO Uniform Plumbing Code and the National Fire Protection Association’s NFPA 13.10.3.

The current state of practice, often referred to as the “skill of the craft,” suggests that pipes should be turned 2 to 3 full turns beyond hand-tightening to ensure proper installation. Recognizing this gap in standardization, the research team at the University of Nevada, Reno embarked on a study with the goal of creating a torque chart, akin to those available for bolts.

This study focused on twelve specimens ranging in size from 1 to 2 inches. During the torqueing process, strain within the fittings was closely monitored to determine the appropriate torque levels required for secure assembly.

This paper outlines the methodology adopted for the experiments, examines correlations among various pipe sizes, and delves into the impact of over-torqueing on fitting performance. It also highlights the challenges faced in establishing a standardized torque-based approach to pipe assemblies with cast-iron fittings. Furthermore, the paper introduces an alternative approach to standardization based on the number of unused female threads remaining.
Root Cause Analysis of Expansion Joint Internal Sleeve Failure Under Reverse Flow Conditions Using Computational Modelling
Authors: Harris Chase , Bayram Ahmed , Sanati Mehdi , Harper Chris , Silva-Rivas Jose
Published: November 2024

An expansion joint is a piping component that allows flexibility to absorb thermal and dynamic loads. Many expansion joints have internal sleeves that separate the flow from bellow convolutions. Current EJMA standards do not give detailed guidance on designing these sleeves for reverse flow conditions. An industry design utilizes longitudinal slots in the sleeve to equalize pressure on the inner and outer surfaces. This paper presents a case study to investigate the failure mechanism of this phenomena, verify analytical results with field findings, and suggest a methodology to easily qualify internal sleeves for reverse flow. A combination of Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) is used to employ a one-way coupled Fluid Structure Interaction (FSI). The study considers the nonlinear relationship between large deformations, applied fluid pressures, and pressure equalization slot closure. Factors such as flow speed, turbulence profiles, and bellow angulation are varied in this analysis. Results are compared with ASME Section VIII Division 2 criteria for plastic collapse failure and a reasonable limit of flow speed is determined to avoid plastic collapse. This case study may provide guidance for further research and standard development.
Investigation Into the Effects of Cladding in Thermal Fatigue Evaluations of Nuclear Pressure Vessels and Components
Authors: Pellereau Ben , Hockly Meyrick , Reinhardt Wolf
Published: November 2024

Many nuclear components are clad with corrosion resistant material to protect the parent material from the environmental effects of the coolant. Often, the cladding is achieved by weld depositing one or more layers of cladding material to the inside surface of the component; typical cladding materials include austenitic stainless steel and nickel-based alloys.

Rules for the assessment of clad components in Paragraph NB-3122 of Section III of the ASME Boiler and Pressure Vessel Code allow the presence of the cladding to be neglected in analysis provided the cladding is integrally bonded and sufficiently thin.

Different code users appear to have interpreted this exemption in different ways with some neglecting the cladding in both the thermal and stress analysis and others including it in the thermal analysis but neglecting it in the stress analysis and others potentially including it in both, but only assessing the parent material for fatigue. When the environmental effects on fatigue are to be considered, additional questions arise, for example whether the fatigue analysis of the cladding might now become necessary or whether environmental effects need to be considered for the base material.

This paper uses a range of simple finite element models to study the effects of including or excluding cladding from the analysis. Models of typical plant components with a range of cladding thicknesses (between 3% and 10% of total wall thickness with austenitic and nickel-based alloy cladding) are analysed under representative long range and short-range transients. The cladding has been excluded from different stages of the calculation (thermal analysis, stress analysis, fatigue evaluation and application of environmental enhancement factor) and the results from the different assessments are compared to evaluate the different interpretations of the current code rules.
Steps in Application of the Alternative Nozzle Reinforcement Rules for Gasketed Plate Heat Exchangers
Authors: Nikic Milan , Srnic Djordje
Published: November 2024

This paper is a continuation of the work of previously developed alternative nozzle reinforcement rules for gasketed plate heat exchanger (GPHE) end plates. A staged approach has been adopted in the framework of development of the alternative rules. In the first stage, an analytical approach has been utilized using the basis of ASME BPVC Section VIII, Div. 1, Section UG-39, and the principles and data of a simply supported plate theory. In the second stage, Finite Element Analysis (FEA) has been conducted with an aim to expand and refine the alternative nozzle reinforcement rules for GPHE end plates. The philosophy that has been followed in development of the alternative rules assessed the impact of nozzle size and location on bending stresses in the GPHE end plates with the goal to optimize the design thickness of the GPHE end plates. Additionally, the limits of the design approach have been defined.

The objective of this paper is to present application of the alternative nozzle reinforcement rules for GPHE in a concise step-by-step manner. Additionally, the paper will present the geometrical limitations for the application of the rules. Overall, the paper would conclude the work of development of the alternative nozzle reinforcement rules for GPHE by incorporating the results of the previous two stages of the work conducted and published.
Fracture Toughness Test Methods for Material Qualification in Gaseous Hydrogen
Authors: Bezensek Bostjan , Hopkin Sarah , Martin Tom , Guijt Wim , Shie Taylor
Published: November 2024

This paper focuses on the use of a variety of different small scale test methods to assess the fracture resistance of the material in gaseous hydrogen and study susceptibility to subcritical crack growth. The test methods include ASTM E1681 constant load and constant displacement approaches, the ASTM E1820 rising displacement approach and a modified ASTM F1624 with additional fatigue pre-conditioning in a defined manner per the DNV method (also called ‘constant K’ method). The study shows similitude in the threshold toughness results with the methods that do not involve fatigue pre-conditioning. The toughness threshold defined at Δa≈0mm from the rising displacement J-R curve is preferred and gives a similar toughness threshold to the constant load test method. However, when a defined fatigue crack growth is preceding the fracture test the local crack sharpening effect can dramatically reduce the threshold for the onset of stable subcritical crack growth in certain microstructures such as vintage textured ferritic-pearlitic microstructure.
Effect of Temperature on the Crevice Corrosion Propagation on Flange Faces
Authors: Hakimian Soroosh , Bouzid Abdel-Hakim , Hof Lucas A.
Published: November 2024

The corrosion of flange faces poses a significant risk to the structural integrity of bolted flanged connections and can lead to severe leakage problems. It has been observed on multiple occasions that bolted flanged joints experience premature failure due to crevice corrosion on the flange faces, where the gasket is positioned, and these areas are not accessible nor visible. Crevice corrosion occurs due to the breakdown of the passive layer in an occluded area, specifically at the flange and gasket interface, greatly increasing the corrosion rate of the flange compared to general corrosion. The breakdown of the passive layer is a challenging phenomenon, occurring on a small scale and within a short period, making it difficult to detect through regular inspection methods. The propagation of crevice corrosion can be significantly influenced by working conditions. Given that the crevice geometry is one of the most influential factors in crevice corrosion, the specially designed COrrosion Quantification Test (COQT) fixture, introduced in previous papers, is utilized in this research, allowing the application of various electrochemical techniques to assess flange corrosion under a controlled environment. The primary objective of this research is to propose a methodology for measuring and comparing the crevice corrosion propagation rate of flange faces under different temperatures and fluid flow rates. The chemical composition of the flange specimens complies with ASTM A182 F321 stainless steel, while the gasket is a sheet graphite with no inhibitors. The results from potentiostatic polarization tests reveal an increase in crevice corrosion rate with elevated temperatures. Moreover, crevice corrosion rate decreases with the fluid flow rate increase. These findings highlight the influence of mass transport in controlling crevice corrosion propagation rates.
Research on Semi-Empirical Calculation Formula of Bursting Pressure Design of Ultra-High Pressure Bursting Disc
Authors: Yang Chao , Hui Hu , Luo Hui , Bo Ke
Published: November 2024

As a safety relief device for pressure vessel, bursting disc is widely used in various pressure equipment for its simple structure, strong airtightness, large emission capacity, wide adaptability, sensitive overpressure response and other characteristics, which plays an important role in ensuring the safety of pressure equipment in complex environment. With the development of society and economy, pressure vessel is developed towards the direction of extreme and lightweight. In this paper, a semi-empirical formula for calculating the bursting pressure of ultra-high pressure bursting disc design is presented. The non-uniform thinning of the wall thickness after pre-arch deformation of ultra-high pressure bursting disc is measured. The theoretical calculation formula of nonuniform thinning wall thickness after deformation of bursting disc is established based on the hypothesis that the bursting disc is spherical after deformation. In order further simplify the calculation formula and process of semi-empirical formula, test data of different materials, bursting pressure and deflection height are selected to establish the correlation between the deflection height of bursting disc and the strain hardening index of material. The semi-empirical formulations of the designed blasting pressure are simplified, and the numerical simulation and experimental verification of the blasting pressure of the bursting disc are carried out by using experimental method to verify the accuracy of the calculation results of the semi-empirical formula and simplified formula of the designed blasting pressure.
Residual Stress in 347H Weldments: Influence of Various Thermal Treatment on Residual Stress Reduction
Authors: Yang Yi , Gao Yanfei , Feng Zhili , Bunn Jeffrey R. , Payzant E. Andrew , Penso Jorge
Published: November 2024

Residual stresses play a pivotal role in influencing the structural integrity of welded structures, a consequence inherent to the welding process itself. In scenarios involving cyclic thermal and mechanical loading during operation, the dynamic transformation of residual stress patterns arises from multiple influencing factors. In addition to thermomechanical considerations, the evolution of the microstructure significantly contributes to this intricate and interconnected phenomenon. The selection of 347H austenitic stainless steel stands out as an optimal choice due to its exceptional resistance to creep and corrosion. Nonetheless, unforeseen failures continue to pose significant challenges in meeting design criteria. Residual stress remains the primary factor for predicting the lifetime of welded components, and a reliable measurement method for this purpose is still lacking. In this research paper, we present a comprehensive series of measurements conducted on lab-made plate welds subjected to different thermal treatment conditions. Simultaneously, we employ and compare two distinct calculation methodologies to assess the disparities and the feasibility of applying the plane stress methodology to thick service pipe welds. Through a meticulous measurement plan encompassing both As-Welded and post-weld heat treatment (PWHT) lab-made plate welds, which aim to determine the impact of PWHT on the redistribution and relaxation of the residual stress field. Additionally, both plate welds undergo 361.5 hours of thermal aging (TA) at 650°C to mimic as practical as possible service conditions. The validation of both methodologies is subsequently established across four distinct thermal treatment conditions. Consequently, the reliable application of the plane stress methodology to service-grade thin/thick pipes becomes apparent.
Using Computational Fracture Mechanics With the API 579-1/ASME FFS-1 Annex 9H Procedure
Authors: Blanks Daniel
Published: November 2024

The 2021 edition of API 579-1/ASME FFS-1 Fitness-For-Service (API 579) includes a new annex, Annex 9H, which contains a procedure to reduce conservatism in the calculation of the toughness ratio, Kr, in a Fitness-For-Service (FFS) Assessment of a crack-like flaw to API 579 Part 9. The Annex 9H procedure incorporates constraint effects (based on T-stress, a measure of crack front constraint) to improve the fracture toughness, Kmat. Applying Annex 9H reduces the Kr value in the Failure Assessment Diagram (FAD) used to determine if the crack-like flaw is acceptable or unacceptable.

However, the procedure in this annex is limited in its application. Annex 9H can only be applied to surface-breaking semi-elliptical, crack-like flaws in flat plate and cylindrical shell geometries when the stress distribution across the flaw plane can be accurately represented by linearization. Using computational fracture mechanics, the procedure can be expanded and applied to the general case of a surface-breaking, crack-like flaw in a component under any stress distribution.

A procedure is proposed that enables Annex 9H to be implemented in an FFS assessment carried out using computational fracture mechanics three-dimensional (3D) crack meshes with Finite Element Analysis (FEA). This paper details two studies in which 3D crack meshes were created to compute T-stress at the crack front using FEA. T-stress is computed using a linear-elastic FEA and provides the values needed to apply Annex 9H procedures.

Comparisons are made between estimating fracture toughness following the typical Part 9 procedures and those incorporating Annex 9H, with and without computational fracture mechanics. Application of the procedures in WRC Bulletin 590, which provides a method that essentially expands on the Annex 9H procedure for non-linear stress distributions, is also compared. Lastly, the resulting improvement in Kmat, which influences the final FFS outcome, is compared and reviewed. Recommendations are also provided regarding potential additions to the Annex 9H and WRC Bulletin 590 procedures to obtain the most accurate solution.
Fracture Analysis With Residual Stresses From Local Post-Weld Heat Treatment
Authors: Billon François , Jourden Erwan , Miguet Anthony , Moreau François , Willaume Pierre , Mouchette Laurent
Published: November 2024

This study, based on calculations performed by Framatome and ESI Group with ONET Technologies for ONET Technologies Nuclear Pressure Equipment (NPSE) justification, deals with an industrial case which consists of a numerical simulation of a Post Weld Heat Treatment (PWHT) of a butt weld of a Level 1 NPSE and its associated robustness analysis.

The limited local heated length is the source of local thermal gradients in the longitudinal direction because of the existence of transitions between hot and cold parts at the ends of the heated zones.

Temperature repartition in the structure is evaluated thanks to finite element analysis and reconciliation with in-situ temperature sensors by iterative parametric approach to determine the corresponding heat loadings.

These local gradients with high temperature differential generate inelastic deformations (plasticity-creep) and consequently residual stresses in the heat-treated substructures. These residual stresses are considered by combining them with the stresses obtained in operating situations, being the subject of a codified Stress Analysis Report (SAR), in order, in the presence of a technological defect, to calculate its propagation by fatigue (initiation and propagation) and to verify the associated robustness criteria based on the determination of a combined stress intensity factor (KCOMB) being compared to the toughness (KIC).

This robustness analysis is carried out by methods described in AFCEN Codes (initiation as well as propagation according to RCC-M; stability calculation according to RSE-M).
Pathways to reduce global plastic waste mismanagement and greenhouse gas emissions by 2050
Authors: Pottinger A. Samuel , Geyer Roland , Biyani Nivedita , Martinez Ciera C. , Nathan Neil , Morse Molly R. , Liu Chao , Hu Shanying , de Bruyn Magali , Boettiger Carl , Baker Elijah , McCauley Douglas J.
Published: November 2024

Plastic production and plastic pollution have a negative effect on our environment, environmental justice, and climate change. Using detailed global and regional plastics datasets coupled with socioeconomic data, we employ machine learning to predict that, without intervention, annual mismanaged plastic waste will nearly double to 121 million metric tonnes (Mt) [100 to 139 Mt 95% confidence interval] by 2050. Annual greenhouse gas emissions from the plastic system are projected to grow by 37% to 3.35 billion tonnes CO
2
equivalent (3.09 to 3.54) over the same period. The United Nations plastic pollution treaty presents an opportunity to reshape these outcomes. We simulate eight candidate treaty policies and find that just four could together reduce mismanaged plastic waste by 91% (86 to 98%) and gross plastic–related greenhouse gas emissions by one-third.
Safety, outcomes, and pharmacokinetics of isavuconazole as a treatment for invasive fungal diseases in pediatric patients: a non-comparative phase 2 trial
Authors: Segers Heidi , Deville Jaime G. , Muller William J. , Manzanares Angela , Desai Amit , Neely Michael , Bordon Victoria , Hanisch Benjamin , Lassaletta Alvaro , Fisher Brian T. , Autmizguine Julie , Groll Andreas H. , Sinnar Shamim , Croos-Dabrera Rodney , Engelhardt Marc , Jones Mark , Kovanda Laura L. , Arrieta Antonio C.
Published: November 2024

Invasive aspergillosis (IA) and mucormycosis (IM) cause significant morbidity and mortality in immunocompromised and/or hospitalized patients. Isavuconazonium sulfate, a prodrug of the antifungal triazole isavuconazole, has been approved for treatment of IA and IM in adults; and was recently approved in children. This study describes the outcomes, safety, and pharmacokinetics of isavuconazole for the treatment of proven, probable, or possible IA or IM in children. In this phase 2, open-label, non-comparative study, patients aged 1 to <18 years with at least possible invasive mold disease were enrolled across 10 centers in the US, Spain, and Belgium from 2019 to 2022. Patients received 10 mg/kg isavuconazonium sulfate daily (maximum 372 mg; equivalent to 5.4 mg/kg or 200 mg isavuconazole) for up to 84 (IA) or 180 days (IM). Outcomes included rates of all-cause case fatality, overall response, treatment-emergent adverse events (TEAEs), and pharmacokinetics. Of 31 patients enrolled, 61.3% were 1–<12 years old; 58.1% had underlying hematologic malignancies. The successful overall response rate at the end of treatment was 54.8%. Day 42 all-cause case fatality was 6.5%; 93.5% experienced TEAEs, and two patients discontinued treatment due to drug-related TEAEs. Dosing at 10 mg/kg (maximum dose: 372 mg) met the pre-defined exposure threshold of above the 25th percentile for the area under the concentration-time curve (≥60 mg·h/L). Simulated doses of 15 mg/kg improved drug exposures in patients aged 1–<3 years. Isavuconazole was well tolerated in children, with exposure consistent with adult studies. Successful response was documented in 54.8% of patients.

CLINICAL TRIALS

This study is registered at
ClinicalTrials.gov
as
NCT03816176
.
Uterine-enhanced myometrial vascularity: minimal-invasive management with uterine artery embolisation
Authors: Tripathy Taraprasad , Patel Ranjan Kumar , Vats Aditi , Singh Sweta
Published: November 2024

Uterine-enhanced myometrial vascularity (EMV) is a rare complication following abortion/medical termination of pregnancy or postuterine instrumentation, which can lead to severe anaemia and could even be life-threatening in some cases. Several invasive surgical treatment methods are available for management. Recently, minimally invasive embolisation of uterine arteries has been emerging as an effective alternative management method with promising results. In this case report, we aim to describe a case of uterine EMV in a young female presenting with bleeding, which was successfully managed with uterine artery embolisation.
Widening the phenotypic spectrum caused by pathogenicPDX1variants in individuals with neonatal diabetes
Authors: Jeffery Nicola , Al Nimri Omar , Houghton Jayne A L , Globa Evgenia , Wakeling Matthew N , Flanagan Sarah E , Hattersley Andrew T , Patel Kashyap Amratlal , De Franco Elisa
Published: November 2024

Introduction

BiallelicPDX1variants are a rare cause of isolated pancreatic agenesis and neonatal diabetes (NDM) without exocrine pancreatic insufficiency, with 17 cases reported in the literature.

Research design and methods

To determine the phenotypic variability caused by this rare genetic aetiology, we investigated 19 individuals with NDM resulting from biallelic disease-causingPDX1variants.

Results

Of the 19 individuals, 8 (42%) were confirmed to have exocrine insufficiency requiring replacement therapy. Twelve individuals (63.2%) had extrapancreatic features, including 8 (42%) with conditions affecting the duodenum and/or hepatobiliary tract. Defects in duodenum development are consistent with previousPdx1ablation studies in mice which showed abnormal rostral duodenum development.

Conclusions

Our findings show that recessivePDX1variants can cause a syndromic form of NDM, highlighting the need for clinical assessment of extrapancreatic features in individuals with NDM caused byPDX1variants.
Enhanced immune responses are accompanied by increased MAGEA expression in osteosarcoma metastases
Authors: Meijer Debora M , van Oost Siddh , Roelands Jessica P , Ruano Dina , Briaire-de Bruijn I H , van den Akker B E , Kruisselbrink A B , Wijers-Koster P M , van der Ploeg Manon , Ijsselsteijn Marieke , Lam S W , de Ru Arnoud H , Tjokrodirijo R T N , van de Sande M A J , Gelderblom Hans , Van Veelen Peter A , Kuijjer M L , de Miranda Noel , Bovee Judith V M G
Published: November 2024

Objective

Osteosarcoma is the most common primary bone sarcoma. About 50% of patients develop metastatic disease and their 5-year survival lingers at around 20%–30%. T cell checkpoint blockade immunotherapies have revolutionised cancer treatment in the last decade, but their impact remains limited in osteosarcoma.

Methods and analysis

In order to reveal potentially novel immunotherapeutic strategies for advanced osteosarcoma, we conducted an immunogenomic characterisation of a unique sample set comprising 30 osteosarcoma samples from seven patients, collected throughout disease progression. We performed RNA-sequencing and imaging mass cytometry analysis on these samples to reveal the immunological landscape during osteosarcoma progression.

Results

Transcriptional and phenotypical hallmarks of cytotoxic T cell-driven anticancer immunity were enriched in metastatic lesions as compared with primary tumours. Spatial analysis showed T cells infiltrating central regions of osteosarcoma metastases, indicating the absence of an immune excluded environment. In parallel, we found a pronounced increase in the expression of cancer testis antigens, particularly melanoma antigen family A (MAGEA)-related antigens, in osteosarcoma metastases, which was validated in an independent cohort (N=91). In addition, we demonstrated the presentation of MAGE-derived peptides in three out of four osteosarcoma cell lines.

Conclusion

These findings indicate a concurrent augmentation of cytotoxic antitumour immune responses and expression of MAGEA antigens from primary to metastatic osteosarcoma. This observation suggests the exploration of MAGEA antigens as potential targets for immunotherapy in the treatment of advanced osteosarcoma.
Comparison of the aetiology, microbiological isolates and antibiotic susceptibilities of endophthalmitis between children and adults in southern China: a retrospective, cohort study
Authors: Yang Yao , Lin Jiaqi , Li Yujie , Ding Xiaohu , Liu Manli , Zeng Jieting , Lin Xiaofeng , Duan Fang
Published: November 2024

Objectives

To compare aetiology, microbiological isolates and antibiotic susceptibilities of endophthalmitis between children and adults.

Design

Retrospective observational study.

Participants

Patients admitted to Zhongshan Ophthalmic Center between January 2013 and December 2019 with clinically diagnosed endophthalmitis were included.

Outcome measures

The aetiology, microbiological isolates and antibiotic susceptibilities of endophthalmitis were analysed.

Results

Of 1803 patients, 430 (23.8%) were aged ≤16 years. In both children and adults, the main aetiology was trauma (85.6% vs 64.7%, p<0.05).Streptococcusspecies (spp.) (28.8%) were most prevalent in paediatric post-traumatic endophthalmitis; whereas, coagulase-negative staphylococci (36.9%) were dominant in adults. In postoperative endophthalmitis, all children had bacterial infections, while fungal infections accounted for 12.5% in adults. In endogenous endophthalmitis caused by fungi,Candidawas most prevalent in adults (26.9%); whereas, all causative fungi involved filamentous fungi in children. Isolated bacteria in children presented a higher susceptibility in 7 of 11 antibiotics compared with those in adults. Levofloxacin had the highest susceptibility rate in children (97.9%), and ofloxacin had the highest susceptibility rate in adults (90.6%).

Conclusion

The main aetiology was trauma, with a higher proportion in children than in adults. The microbial profile of paediatric endophthalmitis was different from those of adults. Susceptibilities of causative bacteria to most antibiotics were higher in children than in adults.