bluuebunny/crossref_metadata_2025 huggingface dataset:
New Breech-Lock Exchanger Design to Ensure Gasket Sealing Under All Conditions
Authors: Groppi Roberto , Jibb Richard J. , Creech David T.
Published: November 2022

High pressure threaded closures designed to ASME VIII Div.1 and Div. 2 are used extensively in heat exchangers in the hydroprocessing industry, where design conditions in excess of 100 bar and 450 °C may be required. When there is a requirement to open for inspection and maintenance, the breech-lock or screw-plug design offers a cost-effective alternative to TEMA channel closure types because it eliminates the large cover flange and bolting (often associated to welded diaphragms), allows for sealing adjustments without being dismantled and provides quicker opening and closing operations. For services designed to operate with a pressure differential between circuits that cannot be isolated (High-High type) an internal assembly must be designed such that the sealing of the tubesheet gasket is maintained under all possible operating conditions. The assembly must transfer the loads from the bolts to the tubesheet gasket but also remain elastic over a range of operating conditions.

The past work on this assembly type is reviewed and root causes of exchanger leaks reported in the literature are discussed. A finite element analysis study showed that typical designs for the internal load-carrying components undergo plastic deformation due to thermal expansion under certain operating conditions, leading to a loss of gasket seal. While sealing may be temporarily restored by acting on external bolts, for example by hot torquing, subsequent thermal cycles can result in further deformation such that the assembly may require unplanned maintenance or repair.

The results of the study were used to guide development of a new closure concept using a conical disc spring to ensure adequate gasket stress for sealing of the tubesheet while maintaining elastic behavior of components under load for all anticipated operating conditions, including upsets. Finite element models were used to compare the new approach to the existing practice and to design a demonstration unit, which has since been fabricated. The conical disk spring for the demonstration unit was tested, confirming the elastic behavior over the anticipated load range and enabling calibration of strain gauges. The complete prototype was tested with mechanical and thermal loads to validate analysis results and confirm ease of assembly and disassembly. The new closure design can reduce plant shutdown time by eliminating leaks and damage during operation of screw-plug exchangers.
Review on Inspection Status of Pressure Equipment in LNG Receiving Station in China
Authors: Duan Zhixiang , Shi Kun , Zhou Yunyi , Hu Hangjian
Published: November 2022

Liquefied natural gas (LNG) terminal has the main functions of LNG unloading, storage and gasification, and occupies an important position in civil natural gas and industrial natural gas. In recent years, the pressure equipment of receiving terminals in China has reached the inspection period one after another, and periodic inspection has been carried out one after another.

The current situation of inspection and detection of pressure equipment in LNG terminal in China are summarized, and the conventional inspection technology and the RBI online inspection of pressure equipment in LNG terminal are analyzed. It is concluded that visual inspection, transient electromagnetic, pulsed eddy current, electromagnetic ultrasound, infrared thermal imaging, digital ray inspection, vacuum detection and other detection means can be used in online inspection. The inspection shall conduct risk analysis in combination with the characteristics of the plant and equipment, determine the detection strategy and select appropriate detection means.

The current situation of China’s laws, regulations and standards on the inspection of pressure equipment in LNG terminal are analyzed also. And it is considered that the laws, regulations and standards on the inspection and detection of pressure equipment in LNG terminal are not perfect. It is suggested to put forward the specific requirements for the online inspection and detection methods of LNG pressure equipment as soon as possible and issue the corresponding laws and standards.
Environment Assisted Fatigue – Experimental Challenges and Solutions
Authors: Solin Jussi , Seppänen Tommi , Vanninen Rami , Pulkkinen Erkki , Lemettinen Petri
Published: November 2022

The design fatigue curves applied for safety class 1 components in NPP’s are based on an experimentally determined strain-life fatigue data, the resulting ε-N reference curves and transferability margins. To account for detrimental effects of coolant water environment, penalty factors (Fen) are obtained by comparing fatigue lives in air and environment. To avoid bias in comparison, the same fatigue testing procedures according to ASTM E606 would be preferred in both environments. However, modified EAF test procedures were developed when direct control of strain in the specimen gauge section was not possible.

This paper introduces and discusses commonly used experimental approaches for conducting (directly or remotely) strain-controlled fatigue tests in simulated LWR coolant water environments. At or near gauge section remotely controlled and tubular specimens have been successfully used to determine penalty factors for fatigue usage in environment, but variation and uncertainties related to experimental methods used for collecting the data cannot be completely excluded. The challenges and solutions adopted during latest 20 years in Finland are explained.
Implementing Probabilistic Design Methods in Plant Systems Design
Authors: Mann J. Adin , Pellereau Ben , Diaconeasa Mihai A. , Martin Michael , Prinja Nawal K.
Published: November 2022

An American Society of Mechanical Engineers (ASME) standard for design of facilities with potential for significant hazards to the health and safety of the public, the worker, and the environment is being developed. The standard includes requirements and guidance for design organizations to incorporate risk informed probabilistic design methodologies with traditional deterministic design methods using reliability and availability targets. Probabilistic design processes include selecting the systems and products to be evaluated, defining the failure modes, establishing system life cycle models, defining the acceptance criteria, selecting the appropriate probabilistic design method, processing the analysis results, and, where applicable, recommending design changes. The order of these activities as well as the inputs and outputs from each step are defined. Probabilistic design methods are addressed at both the system and product level and their interaction. A toolbox of probabilistic design methods is included as an appendix to the standard. A description of the current plans for each activity, the order of activities, and the input and outputs from each activity are described along with the interaction to the other activities in the plant system design process. The basic content and organization of the toolbox is described. This paper provides an overview of the probabilistic analysis section rather than a detailed description of the draft document or examples.
CPS – an Advanced Tool for Monitoring Fatigue and Fracture on Pipes and Other Mechanical Components
Authors: Wackenhut Georg , Lammert Robert , Silber Fabian , Weihe Stefan
Published: November 2022

Current economic challenges as well as requirements arising from environmental protection aspects enforce manufacturers and operators of technical systems to search for innovative solutions. This especially applies to components subjected to alternating loads.

A safe but also efficient operation of components requires that the loads encountered during operation are continuously recorded in order to be able to evaluate or predict their lifetime consumption.

A long operation time requires that the whole lifetime period is controlled by appropriate monitoring systems. In cases where cracks and crack growth are acceptable or even inevitable, the lifetime assessment procedure can be combined with suitable crack growth monitoring systems and (fracture mechanics) evaluation procedures.

CPS, as an acronym for Control, Perspective and Strategy, is a software tool which is intended for monitoring an arbitrary large number of subsystems of a complex technical system, e.g. a power plant. Thereby, any subcomponent subjected to alternating loads, e.g. pipe or some other kind of mechanical component, can be evaluated with regard to fatigue as well as crack growth. This contribution strives to show how a safe and efficient long term operation can be achieved while also considering the results of non-destructive testing (NDT) obtained from the corresponding operation accompanying processes.
Technical Basis for Proposed Code Case on Evaluation of Flaws in Butt Fusion Joints in Class 3 High Density Polyethylene Piping
Authors: Liu Cheng , Scarth Douglas , Munson Douglas
Published: November 2022

There is a need for ASME B&PV Code procedures and acceptance criteria for evaluation of flaws detected by inspection of high density polyethylene (HDPE) piping items in safety Class 3 systems. A Section XI Code Case is proposed to evaluate circumferentially orientated planar flaws in butt fusion joints in PE4710 HDPE pipes with a parent material minimum PENT rating of 2,000 hours. The proposed Code Case contains flaw evaluation procedures and acceptance criteria for both surface and subsurface flaws. Two sets of acceptance criteria that are in terms of the allowable stress intensity factor and the allowable flaw size are provided in the proposed Code Case. The calculation of the allowable stress intensity factor is based on the statistical model documented in the paper PVP2020-21783. The model was developed for predicting the time to failure of a butt fusion joint containing a flaw in an HDPE pipe with a parent material PENT rating of 10,000 hours. This paper provides the technical basis for the application of the statistical model to flaws in butt fusion joints in HDPE pipes with a parent material PENT rating between 2,000 and 10,000 hours. For a piping lifetime of 50 years, simplified engineering equations to calculate the allowable stress intensity factor have been developed, and example calculations of the allowable flaw sizes at the maximum Service Level A & B Code allowable temperature of 60°C (140°F) and the stress level of 500 psi (3.45 MPa) are also provided in this paper.
ATLAS+ European Project - Prediction of Large Ductile Tearing in Austenitic Piping
Authors: Blouin Arnaud , Marie Stéphane , Tankoua Franck , Bolinder Tobias
Published: November 2022

In the frame of the European ATLAS+ project it was decided to evaluate if a continuum damage model can simulate a four-points bending test on an austenitic pipe (316L type) with an aged welded joint. To do so, different approaches were used such as GTN model or GFR approach. This paper present the work performed by the different partners.
An Investigation Into the Applicability of Charpy Dynamic Fracture Tests for a Digital Twin
Authors: Sorce Fabian S. , Cogswell Daniel J. , Davies Catrin M.
Published: November 2022

The Charpy impact test has historically been used in a qualitative and comparative manner to infer toughness behaviour and determine the brittle to ductile transition temperature (TBD) of low alloy ferritic steels used in reactor pressure vessels (RPVs). The simple and quick setup makes it an attractive test given the ease of data generation to assess the suitability of a given material; however, the scatter in the data produced is significant and the test does not provide a value of fracture toughness. Quasi-static tests using high-constraint geometries (e.g. single-edge notch bend (SENB) specimens) are used to determine fracture toughness properties, whilst the Charpy impact test (governed by the ASTM E23 and ISO 148 standards) gives insight into the dynamic fracture response of a material. There is significant interest, demonstrated by recent work, in utilising Charpy impact test data to predict fracture toughness properties and material behaviour, which typically require expensive and time-consuming test procedures. The ongoing digital transformation of industry and proposals of digital twins becoming ubiquitous relies intrinsically on high-quality data inputs and fully understanding the underlying mechanistic relationships governing material behaviour. This work examines the relationships between microstructure, temperature, and quasi-static and dynamic fracture behaviour of a low alloy ferritic steel (comparable in composition to SA508). The microstructures are analysed before a Charpy impact pendulum is used to determine the energy absorbed by standard V-notch samples from −196 °C to 200 °C and the fracture surfaces examined. A distinct transition zone is observed and the data is compared to historic fracture data of the material. The results are discussed in light of applicability to a digital twin and the framework for a machine learning model to predict the fracture behaviour and reduce error in transition behaviour is proposed.
Natural Crack Growth of Nozzle Corner Crack Using Extended Finite Element Method (XFEM)
Authors: Dominguez Garivalde , Uddin Mohammed , Tran Minh , Shim Do Jun
Published: November 2022

The nozzle corner region in a pressure vessel experiences stress concentration under various loading such as internal pressure and thermal transients. There are many situations in which a postulated or detected flaw at the nozzle corner needs to be addressed for life assessment and fitness-for-service determinations which require stress intensity factor (KI) solutions. To assess the remaining life, the crack growth calculation of nozzle corner crack is typically performed with KI assuming a semi-circular or semi-elliptical crack shape which are limited to KI values at the deepest and surface points of the crack. However, due to the complex geometry of the nozzle corner crack, it is desired to compute KI along the entire crack front. To that end, the extended finite element method (XFEM) which can simulate cracks without the need for modeling the crack-tip can be used to calculate KI along the entire crack front for arbitrary crack shapes. Using the KI values calculated from XFEM, ‘natural’ crack growth can be simulated.

The objective of this paper is to perform a feasibility study in evaluating the fatigue crack growth behavior of a nozzle corner crack using XFEM. For this purpose, an initial circular nozzle corner crack was used for benchmarking the KI values from XFEM against those from a traditional 3-D finite element model. In the next step, the XFEM model was subjected to cyclic internal pressure to grow the crack where the ‘natural’ crack behavior was studied. Using the fatigue crack growth equation (i.e., Paris Law), the succeeding crack profile was calculated for a given number of cycles using the K values from the previous step and the updated crack profile was then used as an initial crack in the next step. This iterative procedure is automated using Python Script in ABAQUS® and the final crack shape is determined for total number of cycles. Finally, the XFEM based fatigue crack growth results were validated using existing experimental data and were also compared against the crack growth results using an existing KI solution.
Design of B16 Standard and Non-Standard Ring Type Joint Flange and Gasket
Authors: Kataoka Shunji
Published: November 2022

Bolted flange joints using ring type joint (RTJ) gasket has been widely used in oil & gas industry especially for high pressure service less than and equals to 2500 psi or high temperature services. Recently performance of other types of gaskets, such as grooved metal and spiral wound gasket are increased and being reviewed, but RTJ is still a first option for many operators and designers. The flange and gasket design details are provided in ASME B16.5 and B16.47 and the details of the gasket and ring facing are provided in B16.20, however, field problem often occurs in construction site, especially the damage of the ring joint facing due to the overloading. Similar troubles have been reported in non-standard flange and when designing flange connection, additional attention should be paid in addition to the standard design procedure shown in ASME Sec.VIII div.1 Mandatory Appendix 2.

To provide a guideline to design the flange joint and determine appropriate bolt load, detailed review and study was conducted. First, past troubles related to ring type joint are introduced, such as gasket coining into flange groove, and groove deformation of spacer component. Second, to clarify the root cause of such troubles, design of B16 flange, especially ring joint gasket size and facing geometry is reviewed and show gasket sizing and stress states varies with flange size and rating. A series of finite element analysis was performed, and analysis results are reviewed in terms of gasket stress, gasket contact pressure, groove stress and deformation.

Finally, several recommendations on the determination of gasket size, flange groove dimension and initial tightening load are explained.
New Strength Theory and Its Application to Determine Burst Pressure of Thick-Wall Pressure Vessels
Authors: Zhu Xian-Kui , Wiersma Bruce , Sindelar Robert , Johnson William R.
Published: November 2022

The classical Tresca and von Mises strength theories have been utilized extensively for pressure vessel and pipeline design. For pressure vessel design, ASME B&PV code was developed using both Tresca and von Mises strength theories, where the yield strength (YS) was used for an elastic design and the ultimate tensile strength (UTS) was used for an elastic-plastic design. For pipeline design, ASME B31.3, B31G, or other codes were developed using the Tresca strength theory coupled with the YS or a flow stress. The flow stress was introduced to reduce over conservatism from the YS and avoid overestimation from the UTS for many steels.

It has been widely accepted that the burst strength of pipelines depends on the UTS and strain hardening rate, n, of the ductile steel. The average shear stress yield theory was thus developed, and the associated burst pressure solution was obtained as a function of UTS and n. Experiments showed that the Zhu-Leis solution provides a reliable prediction of the burst pressure for defect-free thin-wall pipes. In order to extend the Zhu-Leis solution to thick-wall pressure vessels, this work modified the traditional strength theories and obtained new burst pressure solutions for thick-wall pressure vessels.

Three new flow stresses were proposed to describe the tensile strength and plastic flow response for a strain hardening material. The associated strength theories were then developed in terms of the Tresca, von Mises and Zhu-Leis yield criteria. From these new strength theories, three burst pressure solutions were obtained for thick-wall cylinders, where the von Mises solution is an upper bound prediction, Tresca solution is a lower bound prediction, and the Zhu-Leis solution is an averaged prediction of burst pressure for thick-wall vessels. Subsequently, the proposed burst solutions were validated by a large dataset of full-scale burst tests.
Control of Vortex Shedding and Acoustic Resonance of a Circular Cylinder in Cross-Flow
Authors: Noufal Rasha , Alziadeh Mohammed , Mohany Atef
Published: November 2022

This paper presents an experimental study of the aeroacoustics response from a circular cylinder in cross-flow with a control rod. The effectiveness of the control rod on suppressing acoustic resonance excitation is investigated. The control rod diameter-to-circular cylinder diameter ratio (d/D) is fixed at 0.21. The gap (G) between the circular cylinder and the control rod is taken at 0.11D. The rod is placed at several angular positions, which varied from 0° (front stagnation of the main cylinder) to 180° (base of the main cylinder). Phase-locked particle image velocimetry (PIV) measurements are performed during acoustic resonance to visualize the coherent vortex structures downstream of the cylinders. The results show that the placement of the control rod significantly influences the Strouhal periodicity with great dependence on the rod’s angular orientation. Moreover, at some angular positions, the existence of the rod has resulted in a reduction of the sound pressure level (SPL) generated during acoustic resonance excitation. However, at other angular positions, the rod has resulted in a stronger resonance excitation. This behavior is due to the profound effect of the control rod’s angular position on the formation of vortex cores during acoustic resonance. A brief summary of the results is presented herein.
Seismic Fragility Assessment of Steel Industrial Storage Tanks
Authors: Gabbianelli Giammaria , Perrone Daniele , Brunesi Emanuele , Monteiro Ricardo
Published: November 2022

Storage tanks represent one of the most critical components in industrial facilities and building plants, when considering the occurrence of seismic events. The release of dangerous materials, due to their collapse, can be a safety issue in terms of both human life and environmental impact. This paper carries out a seismic performance assessment of a liquid-storage tank installed in an industrial steel moment-resisting frame building. The seismic performance is gauged in terms of fragility curves, which are provided for different limit states affecting the liquid-storage tank. Nonlinear dynamic analyses are performed using two different modelling approaches: the first explicitly accounts for the tank-structure interaction; the other considers the tank as only modelled as a seismic mass. The results discuss the importance of the modelling assumptions to estimate the seismic demand on liquid-storage tanks and corresponding fragility models for different intensity measures. Absolute acceleration floor response spectra are also analysed in detail, concerning the demand characerization. Finally, the study indicates that the intensity measure adopted for secondary components (i.e. peak floor acceleration) is not necessarily optimal threfeore future developments should produce updated fragility curves for non-structural elements, using better performing intensity measures.
Algorithm Improvement of Transfer Matrix Method for Vibration Propagation of Periodic Pipeline Structure
Authors: Zeng Qingna , Wang Donghui , Zang Fenggang , Zhang Yixiong
Published: November 2022

This paper proposes an improved transfer matrix method (TMM) algorithm to calculate frequency response function (FRF) for finite periods of periodic composite pipelines structures. Traditional TMM usually generate instable matrix and inaccurate calculation results for Phononic crystals (PCs) pipeline. Under the assumption that periodic distribution of pipeline structure with no intermediate excitation, the main idea of the improved algorithm is to reasonably divide finite periodic pipeline into several effective segments, then the transfer relationship of state vector for each connected pipe part could be expressed individually, thereby realizing the calculation order reduction by expanding the dimension of overall stiffness matrix. This improved algorithm could effectively avoid cumulative error caused by diagonal sparse matrix operations, thus getting true dynamic response to calculate exact FRF curves. Moreover, this algorithm could fundamentally improve the accuracy and stability of traditional TMM calculations. The transverse FRF for finite periods calculated by improved TMM shows excellent consistency with corresponding band gap structures (BGs), validate the correctness of derived theory and algorithm. This improved TMM algorithm supplies an effective method for FRF calculation of finite pipeline periods, and also provide effective verification of BGs for infinite structures, which could guide the vibration and noise reduction design of pipeline system.
Impact of Thermal Ageing Embrittlement on Westinghouse and Combustion Engineering-Designed Pressurized Water Reactor Pressurizers Based on Pressure-Temperature Limit Comparison
Authors: Scott Alexandria M. , Turicik Louis W. , Hall J. Brian , Udyawar Anees , Freed Amy E. , Long Elliot J.
Published: November 2022

The low alloy steel pressurizer (PZR) vessels in pressurized water reactor (PWR) nuclear power plants are potentially susceptible to embrittlement due to thermal ageing over the life of the plant (40–80 years). This paper determines the amount of PZR thermal ageing embrittlement, which can be accommodated based on a comparison of PZR and the U.S. NRC approved reactor pressure vessel (RPV) 10 CFR 50, Appendix G Pressure-Temperature (P-T) limit curves for the current operating U.S. PWR fleet. The maximum amount of postulated thermal ageing embrittlement, in terms of a shift in nil-ductility reference temperature (ΔRTNDT), which is permissible before the generic PZR P-T limit curves exceed the NRC-approved RPV P-T limit curves is provided in this paper. The generic P-T limit curves are determined for current operating U.S. PWR representative Westinghouse and Combustion Engineering (CE) PZR designs for various levels of postulated thermal ageing embrittlement. The locations for consideration within the PZR are the cylindrical shell to bottom head girth weld (includes consideration of the adjacent shell longitudinal seam weld), lower head region in the vicinity of the heater sleeve penetrations, and the surge nozzle corner region. The methodology to calculate the PZR P-T limit curves is per 10 CFR 50, Appendix G and the 2017 Edition of ASME Section XI, Appendix G. The PZR thermal ageing ΔRTNDT values determined in this paper could be compared to estimated or empirical values of thermal ageing embrittlement to determine if or when PZR embrittlement may impact a plant’s 10 CFR 50, Appendix G heatup and cooldown P T limit curves, and any primary loop pressure boundary design fracture mechanics evaluations.
Diagnosis, Modelling and Assessment of Transient Pressure Events Based on Observed In-Field Evidence
Authors: Prewitt T. J. , Bednorz Michael
Published: November 2022

Intermittent pipe movement due to transient pressure events including vapor column collapse or water hammer events can impart large strains into the pipe, cause damage to the support structure, damage coatings, and cause damage or failure of the pipe. This paper will present a method that has been used with success for determining the pipe stresses and strains and possible cause associated with a transient pressure event based on coating damage evidence gathered from in-field assessments. After constructing a hydraulic model of the piping system, various transient events were modelled to obtain resulting pressure over the transient event’s period at key points along the piping system, such as valves and elbows. A second, more refined finite element model was created to incorporate the pressure values to determine the resulting displacements and stresses to relate to the in-field measurements of the region in question. By comparing the displacements in the model to the field evidence, the models were calibrated, and evaluation of the likely cause of coating damage found in the field was able to be performed. Moreover, the stresses in the pipe during the event are able to be assessed which allows for damage assessments to be conducted and allows for corrective actions to take place. Transient events assessed ranged from valve openings and closures, pump start up, and vapor column collapse.
Modeling Electric-Potential for a Crack Subjected to Corrosion Under Static and Cyclic Loading
Authors: Prakash Raghu V. , Anish C. , Sampath Dhinakaran
Published: November 2022

High strength steels are increasingly being used in applications such as ship hulls and oil and gas pipelines which are subjected to corrosive environment. These steel grades exhibit more than an order of magnitude higher crack growth rates in corrosive environments compared with the crack growth rates in air. A mathematical model is developed based on the slip dissolution mechanism to evaluate the chemistry and potential distributions in the occluded crack. The species distribution due to diffusion and ion migration is evaluated by considering the effect of ferrous hydroxide formation on the transport properties in the electrolyte. It is also found that the potential and pH drop in the crack is affected by the crack tip stress and strain fields. The dissolution of iron at the crack tip is enhanced by the pH drop. Both steady state and transient numerical studies are carried out to determine the evolving crack geometry. Thus, by considering reactions inside the crack, a better representation of the species and potential distributions can be obtained.
Fracture Toughness Behavior of Welded Service Aged Carbon Steels in Mildly Sour Waters
Authors: Rollins Brandon C. , Penso Jorge
Published: November 2022

Cracking of steels in refinery H2S service occurs in two regimes: 1) low pH and 2) high pH. Cracking in the low pH regime (pH < 6 or 7) is associated with ingress of hydrogen from metal dissolution with H2S poisoning the hydrogen recombination reaction. In the high pH regime (pH > 7), cracking requires the presence of species other than just H2S. While this has been a subject of interest since the failure of an amine absorber tower in 1984, limited laboratory testing has been conducted in either regime. The majority of test data that does exist was from studies conducted in more aggressive environments, such as NACE A or NACE B solutions. Additionally, most of the work was conducted on more modern steels rather than service aged of vintage steel. The lack of available data inhibits the ability to perform fitness for service (FFS) assessments without using overly conservative approaches.

A recent test program was undertaken to evaluate the fracture toughness properties of the weld heat-affected zone (HAZ) of an ex-service steel in mildly acidic sour water environments more typical of the downstream refining industry. The results of the test program, including the test environment and approach are discussed. In addition to the test program, the current state of understanding sour water cracking is reviewed relative to both the low pH and high pH regimes. The gaps in the current knowledge are discussed.
The Standardization Work Status and Development Trend of High Pressure Hydrogen Storage Technology
Authors: Jia Xiaoliang , Chen Zhiwei , Li Xiang , Bo Ke , Ji Fang
Published: November 2022

Hydrogen energy is a kind of efficient, clean and pollution-free green energy, so it is considered as an important part of future energy structure. With more and more attention paid to hydrogen energy in the world, many countries have started the strategic layout, development and utilization of hydrogen energy. Standards provide a crucial technical support for guiding technological advance, industrial transformation and the direction of progress. China and other countries in the world have begun to formulate hydrogen energy standards. High pressure hydrogen storage is one of the most important parts in hydrogen energy industry. The maturity of high pressure hydrogen storage technology directly determines whether the strategic goal of hydrogen energy can be realized. Hence, a brief comparative study has been made between China national standards and International organization for standardization standards based on the following five aspects: technical code for hydrogen fueling station construction, hydrogen systems, metallic material compatibility in hydrogen atmosphere, construction of hydrogen storage vessels, inspection of in-service pressure equipment used in hydrogen fueling station. In order to promote the high-quality development of hydrogen energy industry and achieve the goal of “carbon neutrality” and “peak emissions” in China, it is necessary to strengthen standardization in the test methods for evaluating material compatibility in hydrogen atmosphere and method for hydrogen storage vessels construction used in hydrogen fueling station.
Data-Driven Stress Intensity Factor Solutions for Axial Outside Surface Cracks in Thick-Wall Cylinders
Authors: Zhu Xian-Kui , Zhu Jesse B. , Duncan Andrew J.
Published: November 2022

Crack assessment relies on the linear elastic or elastic-plastic fracture mechanics that requires calculation of stress intensity factor, K, in the fitness for service codes, such as API 579 and ASME BPVC Section XI. For a surface crack in a cylinder, the K calculation becomes calculating the influence coefficients G0 and G1 of K in those codes. API 579 provided accurate tabular data of G0 and G1 for selected cylinder sizes (t/Ri), crack aspect ratios (a/c), crack depths (a/t), and crack tip locations. Recently, the curve-fit solutions of G0 and G1 were obtained for surface cracks at the deepest and surface points. For an arbitrary cylinder size, however, three-parameter interpolations are still needed to estimate the G0 and G1.

To avoid performing the complex interpolation, this paper adopts the state-of-the-art machine learning technology to develop data-driven K solutions based on the tabular data of G0 and G1 given in API 579 for axial outside semi-elliptical surface cracks in thick-wall cylinders at the deepest and surface points. The machine learning method utilizes an artificial neural network (ANN), activation function, and optimal learning algorithm to learn and to determine G0 and G1 as a function of the cylinder size (t/Ri), aspect ratio (a/c), and crack depth (a/t) for axial outside surface cracks at the deepest and surface points. The proposed data-driven solutions of G0 and G1 are validated by available curve-fit solutions for the axial outside surface cracks.
State of the Art in CUF-Based Fatigue Assessment & Related Issues From Regulatory and Code Perspectives for Long-Term Operation
Authors: Garud Yogendra
Published: November 2022

Metal fatigue is likely to continue as an important issue to be managed for the anticipated or extended long-term operation of many engineering systems, both at the design stage and during service. Most parts are designed to start with an un-cracked condition and with the goal of their non-failure during operation. As such, the Code procedures and regulations have been developed to address the possibility of (not) developing a crack of engineering significance during the service. This possibility has been addressed on the basis of ensuring adequacy of fatigue performance for a specified period of operation, and the primary tool used for its assessment utilizes the cumulative usage factor (CUF) parameter. Several design factors/assumptions including the use of stress versus load-cycles (S–N) materials tests data and potential environmental effects in service govern the estimation and application of this CUF parameter.

Over the past few decades, many changes or adjustments have influenced the overall CUF-based assessment with some differences also between various international standards and procedures. For the long-term operation (LTO) the regulatory approach has resulted in the time-limited aging analysis (TLAA) or revalidation for fatigue. This paper provides a state-of-the-art overview of these developments, internationally, both in the Code/design rules/norms and the regulatory approaches. Also included is a brief discussion on various technical proposals in active development which are likely to influence the CUF-based assessment and/or to address conservatism in the existing rules and regulations. Brief comments are noted on the characteristically deterministic manner of these approaches and their addressing of the uncertainty in inputs via conservative factors, vis-à-vis a probabilistic approach.
Effect of Pitch Ratio and Flat Bar Support Conditions on FEI Threshold for Low MDP Parallel Triangular Array – Single-Phase Water-Flow
Authors: Elhelaly Amro , Hassan Marwan , Weaver David , Moussa Soha Eid
Published: November 2022

An intensive research program has been initiated to provide a better understanding of the fundamental aspects of FEI in tube bundles. This paper reports the findings of an experimental investigation utilizing a newly commissioned experimental rig. Initially, a series of water-flow experiments were conducted in a fully flexible, low mass damping parameter, parallel triangular tube array (with a cluster of 9 brass rods). To investigate the effect of pitch ratio on the onset of FEI, four different pitch-to-diameter ratios of 1.27, 1.37, 1.48, and 1.62 were utilized and presented in this study. Moreover, to illustrate the dynamic effect of flat bar support conditions on the stability threshold of FEI, a series of experiments were conducted in each pitch ratio with varied tube/support clearances.

A full description of the flow loop, including the utilized instrumentation, and troubleshooting challenges encountered in commissioning the test rig is discussed. Moreover, the obtained results of the single-phase flow experiments are presented. The current results show good agreement with the available data from previous investigations, which established the confidence level needed to start two-phase experiments.
USP7 regulates the ncPRC1 Polycomb axis to stimulate genomic H2AK119ub1 deposition uncoupled from H3K27me3
Authors: Sijm Ayestha , Atlasi Yaser , van der Knaap Jan A. , Wolf van der Meer Joyce , Chalkley Gillian E. , Bezstarosti Karel , Dekkers Dick H. W. , Doff Wouter A. S. , Ozgur Zeliha , van IJcken Wilfred F. J. , Demmers Jeroen A. A. , Verrijzer C. Peter
Published: November 2022

Ubiquitin-specific protease 7 (USP7) has been implicated in cancer progression and neurodevelopment. However, its molecular targets remain poorly characterized. We combined quantitative proteomics, transcriptomics, and epigenomics to define the core USP7 network. Our multi-omics analysis reveals USP7 as a control hub that links genome regulation, tumor suppression, and histone H2A ubiquitylation (H2AK119ub1) by noncanonical Polycomb-repressive complexes (ncPRC1s). USP7 strongly stabilizes ncPRC1.6 and, to a lesser extent, ncPRC1.1. Moreover, USP7 represses expression of AUTS2, which suppresses H2A ubiquitylation by ncPRC1.3/5. Collectively, these USP7 activities promote the genomic deposition of H2AK119ub1 by ncPRC1, especially at transcriptionally repressed loci. Notably, USP7-dependent changes in H2AK119ub1 levels are uncoupled from H3K27me3. Even complete loss of the PRC1 catalytic core and H2AK119ub1 has only a limited effect on H3K27me3. Besides defining the USP7 regulome, our results reveal that H2AK119ub1 dosage is largely disconnected from H3K27me3.
Deconvolution of metal apportionment in bulk metal-organic frameworks
Authors: Xu Jun , Liu Xingwu , Liu Xingchen , Yan Tao , Wan Hongliu , Cao Zhi , Reimer Jeffrey A.
Published: November 2022

We report a general route to decipher the apportionment of metal ions in bulk metal-organic frameworks (MOFs) by solid-state nuclear magnetic resonance spectroscopy. We demonstrate this route in Mg

1−
x

Ni

x

-MOF-74, where we uncover all eight possible atomic-scale Mg/Ni arrangements through identification and quantification of the distinct chemical environments of
13
C-labeled carboxylates as a function of the Ni content. Here, we use magnetic susceptibility, bond pathway, and density functional theory calculations to identify local metal bonding configurations. The results refute the notion of random apportionment from solution synthesis; rather, we reveal that only two of eight Mg/Ni arrangements are preferred in the Ni-incorporated MOFs. These preferred structural arrangements manifest themselves in macroscopic adsorption phenomena as illustrated by CO/CO
2
breakthrough curves. We envision that this nondestructive methodology can be further applied to analyze bulk assembly of other mixed-metal MOFs, greatly extending the knowledge on structure-property relationships of MOFs and their derived materials.
Resetting of zircon inclusions in garnet: Implications for elastic thermobarometry
Authors: Campomenosi Nicola , Angel Ross J. , Alvaro Matteo , Mihailova Boriana
Published: November 2022

Elastic thermobarometry of host-inclusion systems for back-calculating pressure (P) and temperature (T) conditions of inclusion entrapment relies on the assumption that the hostinclusion rheology is purely elastic. In this study, we have explored both the elastic and non-elastic behavior of zircon-in-garnet (ZiG) systems by in situ Raman spectroscopy at high T and ambient P. We show that upon heating, plastic relaxation takes place immediately after the zircon inclusions experience tensile stress conditions with respect to a free crystal at the same T. On subsequent cooling, the inclusions develop a new stress state, and thus the inclusion pressures have been reset from those corresponding to their original entrapment. Resetting of inclusion pressures therefore strongly depends on the exhumation P-T path. This explains why elastic thermobarometry using ZiG systems is reliable when applied to low-P high-T rocks where the cooling path after inclusion entrapment passes quickly into the compression domain of the inclusion. On the other hand, high-P rocks exhumed along quasi-isothermal paths take zircon inclusions into the tensile domain where they are reset until significant cooling commences at low P. ZiG systems in ultrahigh-P rocks therefore commonly indicate pressures on clockwise exhumation paths instead of the conditions of original entrapment.
Improving access to medicines: lessons from 10 years of drug reforms in China, 2009–2020
Authors: Mao Wenhui , Jiang Hongli , Mossialos Elias , Chen Wen
Published: November 2022

China initiated its healthcare reform in 2009 to provide accessible and affordable healthcare to all. We summarised China’s drug reforms between 2009 and 2020 using the WHO framework. China has initiated comprehensive drug policies to address different issues, including: (1) issuing or amending major regulations with changes in institutional settings; (2) implementing the marketing authorisation holder system and bioequivalence assessment to improve the quality of drugs; (3) leveraging accelerated market approval and insurance listing to encourage needs-driven innovation and improve the access to new drugs; (4) introducing compulsory licensing to address major public health threats when needed; (5) scaling up the National Essential Medicine Policy and introducing pharmacoeconomic evaluation in National Reimbursable Drug List to promote rational use of medicine and evidence-based selection; (6) applying differentiated pricing strategies and scaling up zero mark-up policies to form a new financing mechanism; (7) adapting bulk procurement and placing strict regulations on the supply chain management to ensure supply and reduce the cost; (8) empowering pharmacists to improve the rational use of medicine; and (9) using procurement and supply chain digital platforms to inform decision and improve efficiency. China’s drug reform has adopted a phased and systemic approach that mobilises multiple policy levers including governance, regulation and financing. Despite the progress, emerging challenges in implementation, coordination and capacity need to be addressed. Cross-cutting lessons from China’s drug reforms include aligning the drug reform with the overall health reforms, adapting a systemic approach that mobilised policy levers and stakeholders and informing policy decision by conducting pilot studies.
Postoperative analgesic effects of the quadratus lumborum block III and
transversalis fascia plane block in paediatric patients with developmental
dysplasia of the hip undergoing open reduction surgeries: a double-blinded
randomised controlled trial
Authors: Huang Congcong , Zhang Xiaoguang , Dong Chaoxuan , Lian Chunwei , Li Jun , Yu Lingzhi
Published: November 2022

Objective

To evaluate the analgesic effectiveness of two novel regional nerve
blocks in paediatric patients with developmental dysplasia of the hip
(DDH) after open reduction surgeries.

Design

Prospective, double-blinded, randomised controlled trial.

Setting

2 tertiary teaching hospitals in China between August 2017 and July
2018.

Participants

110 paediatric patients aged 2–10 years with DDH undergoing open
reduction surgeries were recruited, 95 were randomised and 90 were
included in the final analysis.

Interventions

Random assignment to quadratus lumborum block III (QLB III) group,
transversalis fascia plane block (TFPB) group and the control (no region
nerve block) group.

Primary and secondary outcome measures

The primary outcome was the Face, Legs, Activity, Cry and
Consolability (FLACC) Scale Scores. Secondary outcomes included
perioperative opioid consumption, the time until first press of
nurse-controlled analgesia/patient-controlled analgesia (NCA/PCA) pump
and the total counts number of pressing, length of postanaesthesia care
unit (PACU) stay, length of hospital stay, parental satisfaction with
pain management and adverse events.

Results

Mean FLACC Scores were significantly lower in QLB III group and TFPB
group while in the PACU and for 48 hours postoperatively, compared with
control group (p<0.0001, p<0.0001, respectively). No differences
were found for FLACC Scores between QLB III group and TFPB group,
neither at rest (p=0.0402) nor while posture changing (p=0.0306). TFPB
prolonged the first-time request for NCA/PCA analgesia, and decreased
the total number of pressing counts, compared with QLB III (22.5 (16.2
to 28.7) vs 11.7 (6.6 to 16.8), p<0.0001; 2.4 (1.3 to 3.6) vs 3.8
(2.8 to 4.8), p=0.0111, respectively). No patient experienced any
adverse events.

Conclusions

We suggested that both ultrasound-guided QLB III and TFPB should be
considered as an option for perioperative analgesia in children with DDH
undergoing open reduction surgeries. TFPB was superior to the QLB III
because it prolonged the first-time request for NCA/PCA analgesia and
decreased the total counts number of pressing.

Trial registration number

NCT03189966/2017.
Parenting, child development and primary care—‘Crescer em Grande!’
intervention (CeG!) based on the Touchpoints approach: a cluster-randomised
controlled trial protocol
Authors: Fareleira Filipa , Xavier Maria Raul , Velte Julia , Teixeira Andreia , Martins Carlos
Published: November 2022

Introduction

Despite support for parenting being already recognised as a
priority, there remains a paucity of evidence on how to facilitate its
adoption in regular visits of maternal and child health primary care
(PC). We describe the protocol for a study to assess the effect of an
innovative universal Touchpoints-based intervention—‘Crescer em Grande!’
(CeG!) - when supporting the process of transition to parenthood and
early infancy, at multiple PC units.

Methods and analysis

A cluster-randomised trial will be conducted in 12 PC units
(clusters) from the Lisbon metropolitan area, Portugal. Participants
will be a minimum of three family physicians and one nurse/unit, as well
as 216 expecting parents and future babies until 18 months who are using
the PC services. Sites will be randomised to either the CeG! or usual
care. The CeG! will consist of: (1) the integration of the Touchpoints
approach in PC maternal and well-child visits, with the support of 28
leaflets for parents to file in a folder; plus (2) training for PC
providers on how to perform the CeG! into existing practice. Parents
will be required to fill in questionnaires at point throughout their
child’s 18-month, mostly online. The primary outcome will be the
self-perception of parental competence (Parenting Sense of Competence
Scale). Other outcomes include: family functioning, couple dynamics,
mental health, well-being/quality of life, psychological experience of
pregnancy, attachment, child development. Acceptability, satisfaction
and feasibility of CeG! will also be obtained from providers’ and
parents’ perspectives. Costs associated with delivering the CeG! will be
calculated. Study analyses will be under the principle of
intention-to-treat.

Ethics and dissemination

Approval was obtained from the Ethics Committee of the Regional
Health Administration. The results will be shared with participants and
disseminated via peer-reviewed published papers, presentations at
scientific and professional conferences.

Trial registration number

NCT90692907