bluuebunny/crossref_metadata_2025 huggingface dataset:
The Causal Nexus between Government Expenditure and Economic Growth: Wagner versus Keynes Hypothesis
Authors: Sek Siok Kun , Yi Sim Khang , Keat Chea Wei , Hui Hoe Zi
Published: November 2023

The causality between economic growth and government expenditure has long been a topic of interest among economists. Theoretically, Wagner’s law claimed that economic growth (EG) contributes to government expenditure (GE), while the opposite causal nexus was claimed by Keynes. This study seeks to test the validity of these two theories by examining four versions of functional hypotheses and their reverse functions: Gupta, Peacock and Wiseman, Musgrave, and Mann. The main objectives include examining the nexus by comparing the developed versus developing countries, short-run versus long-run estimates, and the results between three estimators. The panel data regression applies the three estimators, which include pooled mean group (PMG), mean group (MG), and dynamic fixed effect (DFE). The datasets are collected from 1970 to 2018. The results detect both long-run and short-run relationships in the Gupta version and the Peacock and Wiseman version of Wagner’s law, and also the reverse Gupta version and the reverse Peacock and Wiseman version of Keynes’ theory. To sum up, the two-way relationship between GE and EG exists in developing countries. On the other hand,Wagner’s law and Keynes’ theory are not valid in developed countries. The results imply that economic level matters, which leads to different linkages between EG-GE across groups of countries. Since the nexus exists in developing countries, policymakers should adopt fiscal policies to stimulate economic growth. With no GE and EG relationship found in developed countries, policymakers should focus on other economic indicators other than government expenditure to foster economic growth.
Surface Mount Technology Line Optimisation using Modified k-means with Feature Weight Constraints
Authors: Wong Xian Xiang , Ong Wen Eng , Abd Rahman Siti Amirah
Published: November 2023

The common setup problem for chip mounters in a Surface Mount Technology (SMT) line is to group different device models, each of them consisting of different components, into minimum number of clusters where each cluster has a maximum component size. This type of setup problem is classified as a clustering problem with feature weight constraints which cannot be fulfilled by traditional data clustering. In this study, we introduce some vital modifications on standard k-means algorithm such that it can incorporate feature weight constraints adapted from cluster size constraints. We also propose a modification to the elbow method to determine the number of clusters of the clustering problem with feature weight constraints. The results show that the proposed algorithm (modified k-means with feature weight constraints) is able to fulfill the feature weight constraints and solve the common setup problem. The results verify the proposed algorithm has superior performance over standard k-means algorithm in clustering problem with feature weight constraints. For the common setup problem on a given data set, the analysis shows that 1000 runs of the proposed algorithm implemented using MATLAB is able to obtain at least one valid clustering result within a reasonable run time.
DESIGN OF RAINWATER HARVESTING SYSTEM: BASIC ENGINEERING AND ECONOMICS
Authors: Ogbozige Francis James
Published: November 2023

Residents at the Universal Primary Education (UPE) sand-filled of Borokiri town in Port Harcourt city, Nigeria are facing challenges in obtaining potable water due to numerous factors. Consequently, most residents could not meet the minimum daily per capita water demand set by the United Nations (50 – 100L). The rainfall in Port Harcourt is quite high enough to augment the water scarcity however, the poor quality of the rainwater makes it unsafe. Hence, rainwater harvesting (RWH) system incorporated with treatment facility was designed for an average household of six inhabitants at a daily per capita water demand of 75L. Results showed that the treated water obtained from the designed RWH system was highly potable and the reliability of the designed RWH system for water supply is 75% at a safety factor of 1.22. It was also found that the optimal dimensions of the rectangular rooftop gutters are 170mm width by 100mm depth (including freeboard space) at a bed slope of 1inch in every 10feet. The research further revealed that the designed RWH system is highly economically viable as the net present value (NPV), profitability index (PI) and payback period (PBP) are 747, 439.21Naira, 3.4 and 1.72years respectively, at a discount rate of 15% and lifespan of 15years. Necessary recommendations were made for the inhabitants of the study area, government and non-governmental organizations.
ANALYSIS OF RAINFALL EROSIVITY INDEX USING THE BOLS AND LENVAIN METHODS
Authors: Romdania Yuda , Herison Ahmad
Published: November 2023

Indonesia has a tropical climate, which causes variations in the intensity of rainfall. With a high level of rainfall intensity, Indonesia is vulnerable to. The ability of to cause erosion is called erosivity. The aim of the study was to determine the rain erosivity index as a potential erosion control plan. The employed methods were the Bols and Lenvain methods involving the rainfall consistency test, analysis of average rainfall, and analysis of the erosivity index of rain. The results indicate that only Penengahan Station was eligible for the rainfall analysis with determination coefficient values (R2) of 0.9904 and 0.9889 with the Bols and Lenvain methods respectively. The annual average erosivity index value with the Bols method was 1762.23, while with the Lenvain method, it was 1280.19. With the results in mind, it is safe to infer that the use of the Bols equation is safer to apply to a plan concerning erosion potential mitigation caused by rainfall in the sub-sub watershed area of Khilau as the Bols method yielded a larger value.
BENDING RESISTANCE OF HIGH STRENGTH HOT-ROLLED STEEL UNIVERSAL COLUMN SECTION
Authors: Chung Chen Tat , Moy Jian Jun , Tan Cher Siang , Sulaiman Arizu
Published: November 2023

The most commonly found steel grades in the market are S 275 and S 355 However, recent advancement in the welding techniques allows for the development of high-strength steel for higher grades up to S 700 with reasonable cost and quality to construct heavy-loaded and long spanned structures. To facilitate the selection of the section sizes in accordance to Eurocode 3 Standard, this research focusses on investigate and validate the bending resistance, Mc,Rd and lateral torsional buckling resistance, Mb,Rd of a hot-rolled steel universal column section (UKC) from common steel grades (S 275 and S 355) up to high strength steels (S 460, S 550 and S 650). This study employed Microsoft Excel spreadsheet to develop a program for design calculation for UKC in accordance with Eurocode 3 Standard and compared with the available results provided in SCI P363. The validated program was further applied to develop selection data for high strength UKC steels (S 460, S 550 and S 650). The study outcome suggests that the classification, Mc,Rd and Mb,Rd of the steel is greatly affected by the steel grade. The parametric study in this research also shows that C1 factor, section size and span length can also affect the Mc,Rd and Mb,Rd of the steel, aside from steel grade. Further analysis of high strength UKC steels was done and tabulated since the program developed was validated and employed in the study
THE IMPLEMENTATION OF INTEGRATED MANAGEMENT SYSTEMS (IMS) IN CONSTRUCTION ORGANIZATIONS IN MALAYSIA
Authors: Ramli Nor Fazira , Haron Nuzul Azam , Ales@Alias Aidi Hizami , Harun Aizul Nahar
Published: November 2023

An Integrated Management System (IMS) combines different management systems into one complete system. This paper aims to determine the intention and effectiveness of the IMS being implemented in construction organizations in Malaysia. The problem statement in this study is the number of documents in IMS still needs to be more prominent since the adoption of the standard still needs to be improved. This study aims to give awareness to the company so that they understand their intention to implement the IMS and the effect that will get on the implementation process. This study also will provide a framework that will be a guideline for the company to start with the implementation process and be certified as an IMS company. This study used quantitative and qualitative study methods. The study takes place on the construction company in Klang Valley that implemented the IMS. The survey has been done for the quantitative study to check on the understanding of the company for the intention and effectiveness of the IMS implementation. Meanwhile, for the qualitative study, the semi-structured interview session was done with five subject matter experts (SMEs) in the IMS implantation. The interview validates the research process and the framework's effectiveness. As a result, the study helps the companies to clearly understand their intention to implement the IMS and the effectiveness of IMS in their companies. The framework design also will help the company to have proper guidelines starting from the implementation until the continuous improvement after certification by the certification body.
INVESTIGATION ON PROPERTIES OF READY MIXED CONCRETE OVER TRANSIT TIME
Authors: Chakraborty Pranta , Farhan Muntasir , Das Shuvo Ranjan , Sen Debasish
Published: November 2023

Ready-mixed concrete (RMC) is a contemporary item that facilitate to mix concrete in a specialized yard and deliver it at site while ensuring the quality as fresh concrete. The transit time of RMC, which is influenced by road congestion, is important since it may have an impact on the workability and compressive strength of RMC. Therefore, it is necessary to investigate the impact of transit time on properties of RMC. In this study, a two-phased experimental program was designed; where RMC has been used with (phase-1) and without admixture (phase-2). Concrete mix-ratio was designed to attain M20 concrete; however, the target strength was 25MPa. Fresh concrete properties, i.e., workability, was measured at designated times (i.e., 0, 45, 90, 120, 150, 180 and 210minutes) over a period of 3.5 hours after the mixing of concrete. Over this period, concrete-mixer was continuously rotated at 18-20 rpm speed and cylinders were cast at previously mentioned time intervals. The experimental results showed that transit time has a remarkable impact on workability of RMC when the admixture is not utilized, i.e., slump value reduced from 210 to 25mm over 3.5 hrs. travelling. However, the slump value can be maintained up to 115mm using 1% admixture. In contrast, there is no remarkable impact of transit time on the compressive strength as the average strength in both phases reached or relatively close to the target strength (i.e., 25MPa). The target strength compliance might be attributed to the continuous rotation of the RMC mixer during the transit time
CARBONATION PERFORMANCE OF KAOLIN TREATED WITH GROUND GRANULATED BLAST FURNACE SLAG
Authors: Ayub Azimah , Mohd Yunus Nor Zurairahetty , Abang Hasbollah Dayang Zulaika , Feadrek Brendon , Mohd Zaini Nur Atiqah , A Rashid Ahmad Safuan
Published: November 2023

This study is prompted by the fact that currently available information, regarding carbon dioxide (CO2) and ground improvement, is rather limited, as the emphasis in this area, is mainly directed at health and environmental issues. This includes efforts to counter climate change, by reducing the level of carbon dioxide levels in the atmosphere. Nonetheless, several geotechnical researchers have delved into CO2 sequestration, through magnesium-rich materials. Among such materials is ground granulated blast furnace slag (GGBS). This waste material, which contains between 5% to 9% magnesium, and roughly 35% calcium, appears to be a favourable option for CO2 sequestration. The purpose of this study, is to determine the appropriate optimal amount of GGBS (based on the strength value recommended by the Public Works Department), and its effect in terms of durability, for the treatment of kaolin clay, under ambient and carbonated conditions, with a 24-hour carbonation period, subjected to a CO2 pressure of 200 kPa. Compaction, unconfined compressive strength (UCS), and durability (wetting and drying) tests were performed, with various GGBS contents (5%, 15% and 25%), and curing periods (7, 14, 28 and 60 days). The test results indicate an increase in strength of almost 20 times, for kaolin clay treated with 25% GGBS, with a curing period of 60 days (ambient condition). An additional 22.86% increase in strength was registered, for carbonated conditions. The wetting and drying test, also demonstrated that GGBS-treated kaolin was improved in terms of durability, while retaining its strength under wet and dry conditions. Thus, it can be concluded that with an appropriate amount and curing period, GGBS has the potential to stabilize kaolin clay, and contribute towards the realisation of a more sustainable environment, by curbing the amount of CO2 released into the atmosphere.
FATIGUE CHARACTERISATION OF MARTIAN CONCRETE: A REVIEW
Authors: Samsudin Aina Afiqah , Ahmad Shah Mohamad Shazwan , Umar Sarehati , Mukhlas Nurul 'Azizah , Chiew Teng Ng , Yahaya Nordin , Mohd Pauzi Nurul Noraziemah
Published: November 2023

Spacecraft have been dispatched to Mars as part of human missions aimed at exploring new frontiers, driven by the observed similarities between the red planet and Earth. This endeavour has facilitated the development of construction materials suitable for human settlements on Mars. To determine the optimal properties for constructing habitable infrastructure for humans on Mars, research efforts have led to the discovery of Martian concrete, composed of sulphur and Martian simulants that had been produced without water, which is in scarce supply on Mars. By utilising egolith available near the construction site, structures can be built efficiently and rapidly, supporting the establishment of sustainable human habitats on Mars. Several studies have been conducted to address the challenges associated with identifying the ideal proportions of Martian concrete. Given the extreme and harsh conditions on Mars, there is a growing interest in understanding how the properties of Martian concrete can mitigate and alleviate fatigue resulting from the planet’s daily conditions, such as temperature variations and dusty storms, which impose cyclic loading on structures. Therefore, it is crucial to investigate the fatigue characteristics of Martian concrete. By evaluating the fatigue properties of Martian concrete, considering the selected appropriate mix design ratios, this study aims to contribute to understanding the impact of Martian conditions on construction practices. Ultimately, the findings of this study can assist future researchers in comprehending the effects of the Martian environment on the planet’s construction process.
Loss of mitochondrial Ca2+ uptake protein 3 impairs skeletal muscle calcium handling and exercise capacity
Authors: Roman Barbara , Mastoor Yusuf , Zhang Yingfan , Gross Dennis , Springer Danielle , Liu Chengyu , Glancy Brian , Murphy Elizabeth
Published: November 2023

Mitochondrial calcium concentration ([Ca2+]m) plays an essential role in bioenergetics, and loss of [Ca2+]m homeostasis can trigger diseases and cell death in numerous cell types. Ca2+ uptake into mitochondria occurs via the mitochondrial Ca2+ uniporter (MCU), which is regulated by three mitochondrial Ca2+ uptake (MICU) proteins localized in the intermembrane space, MICU1, 2, and 3. We generated a mouse model of systemic MICU3 ablation and examined its physiological role in skeletal muscle. We found that loss of MICU3 led to impaired exercise capacity. When the muscles were directly stimulated there was a decrease in time to fatigue. MICU3 ablation significantly increased the maximal force of the KO muscle and altered fibre type composition with an increase in the ratio of type IIb (low oxidative capacity) to type IIa (high oxidative capacity) fibres. Furthermore, MICU3‐KO mitochondria have reduced uptake of Ca2+ and increased phosphorylation of pyruvate dehydrogenase, indicating that KO animals contain less Ca2+ in their mitochondria. Skeletal muscle from MICU3‐KO mice exhibited lower net oxidation of NADH during electrically stimulated muscle contraction compared with wild‐type. These data demonstrate that MICU3 plays a role in skeletal muscle physiology by setting the proper threshold for mitochondrial Ca2+ uptake, which is important for matching energy demand and supply in muscle.

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Key points

Mitochondrial calcium uptake is an important regulator of bioenergetics and cell death and is regulated by the mitochondrial calcium uniporter (MCU) and three calcium sensitive regulatory proteins (MICU1, 2 and 3).

Loss of MICU3 leads to impaired exercise capacity and decreased time to skeletal muscle fatigue.

Skeletal muscle from MICU3‐KO mice exhibits a net oxidation of NADH during electrically stimulated muscle contractions, suggesting that MICU3 plays a role in skeletal muscle physiology by matching energy demand and supply.
Effect of Insert Porosity on Combustion Instability in a Lean Premixed Combustor Analyzed by a Proper Orthogonal Decomposition-Based Phase Reconstruction Technique
Authors: Johnson Mitchell , James Ashley , Agrawal Ajay
Published: November 2023

Lean premixed (LPM) combustion is very effective at mitigating emissions but is vulnerable to strong thermoacoustic instabilities. A porous insert in the shape of an annular ring placed at the dump plane of the combustor has been proven to be an effective passive technique for mitigating these instabilities across a wide range of operating conditions. However, it is unclear if the change results from the insert geometry or porosity of the insert. In this study, swirl-stabilized LPM combustion is investigated for three configurations—without any insert, with a porous insert, and with a geometrically similar solid insert. Acoustics, flow, and heat release rate behavior of the three test geometries are investigated using diagnostics including dynamic pressure and acoustic probes, particle image velocimetry (PIV), and OH* chemiluminescence (OH*CL) imaging. Synchronized measurements at a fixed equivalence ratio were acquired at 40 kHz using sound probes and at 3.5 kHz using PIV and OH*CL. Results include time-series and spectral measurements of pressure, velocity, and OH*CL, and mode analysis by proper orthogonal decomposition (POD). In addition, the dynamics of the instability are investigated by high-resolution phase reconstructions of velocity and OH*CL data using a novel implementation of POD introduced in this work. Results show two different instability modes: a longitudinal instability for the solid insert case and a helical, precessing vortex driven instability for the no insert case. In both cases, the flow field and heat release rate oscillations are coupled to produce the instability. No such coupling or oscillations is observed for the porous insert case. These results ascertain the unique capabilities of the porous insert in protecting against instability from different, simultaneous driving mechanisms and demonstrate that the insert porosity and flow dynamics associated with it are the primary mitigating factors.
Film Cooling Performance on a Turbine Blade With Subregional Compound Angle
Authors: Li Guoqing , Li Ang , Zhang Shen , Wang Chenfeng , Lu Xingen
Published: November 2023

Under the influence of secondary flow, the film cooling deviates from the flow direction on the turbine blade, which directly results in undesirable uneven film coverage. On the pressure side, the film appears divergent, while on the suction side, it is bunched. To solve this problem, a kind of subregional compound angle is proposed, in which the angle in the spanwise direction is different in different regions depending on the strength and direction of the secondary flow. Four rows of film holes with five kinds of subregional compound angles are provided on the pressure side, while two rows of film holes with different subregional compound angles are provided on the suction side. The Reynolds Average Navier–Stokes (RANS) method of the SST k–ω turbulence model is chosen to solve the above blade arrangement. The results show that a significant improvement can be achieved by the introducing subregional compound injection of the film coolant compared to the case of simple injection. In compound injection, the injectant maintains sufficient momentum to prevent the coolant from being swept away by the secondary flow. This was found to be largely the case for most holes on the pressure side, and some holes on the suction side. However, for holes near the downstream section of the suction surface of the blade, where the passage vortex is strongest, no value is found for the compound angle that could redirect the coolant along the blade profile without radial deviation. In some cases, excessive values of the compound angle led to jet liftoff rather than spreading the film along the surface.
Numerical Study on Fracture Behavior of Printed Circuit Heat Exchanger Core Based on Elasto-Plastic Phase Field Method
Authors: Shi Qianyu , Zhang Mingbao , Li Qi , Wang Zhijian , Ji Pengzhen
Published: November 2023

Printed circuit heat exchanger (PCHE) is a type of compact heat exchanger with high thermal efficiency, more compact, and suitable for high pressure and high temperature conditions. The safety assessment of PCHE is very important, especially for PCHE core. Because PHCE core is different from the PCHE headers which are typical pressure vessel components. However, there is no standard design method to ensure the structural integrity for PCHE core. Some failure modes of PCHE core are studied in recent years, but seldom researches have been conducted concerning the fracture behavior of PCHE core. In addition, the phase field method for fracture has developed rapidly in recent years with its advantages in predicting crack initiation, bifurcation, and merging. In this work, the fracture behavior of PCHE core with and without defects is investigated based on elasto-plastic phase field method. The model parameter of Ni-based Alloy for elasto-plastic phase field method is first calibrated by comparing the numerical results with tensile test data of diffusion-bonded PHCE core specimen. Then, the influence of loading directions, defect locations, and defect sizes on the fracture behavior of PCHE core with semicircular and semicircular-rectangular channels are analyzed. Some conclusions are discussed.
INCEFA-SCALE Project – Overview of the Modelling Plans
Authors: Courtin Stephan , Ancelet Olivier , Beswick Jack , Blakesley Oliver , Cicero Roman
Published: November 2023

INCEFA-SCALE is a five-year project supported by the European Commission HORIZON2020 programme. It kicked off in September 2020 and is the successor to the INCEFA-PLUS programme. The objective is to continue work, advancing the ability to predict lifetimes of Nuclear Plant components when subjected to Environmental Assisted Fatigue (EAF) loading. The main issue addressed by INCEFA-SCALE is the transferability of laboratory-scale tests to real nuclear components.

The project strategy will be (1) the development of comprehensive mechanistic understanding developed through detailed examination of test specimens and data mining, and (2) testing focussed on particular aspects of component-scale cyclic loading. From these data, one of the main objectives is to derive an EAF assessment procedure that can be used by assessors for the extrapolation of laboratory test data to real component geometries and conditions, for lifetime calculations.

This paper will give an overview of the INCEFA-SCALE modelling plans and some illustrations on the 5 main topics that have been identified: (1) numerical analyses to support test design and interpretation, (2) data mining, (3) review of the codified methods, (4) fatigue damage modelling and non-codified approaches to better address for fatigue damage mechanisms, and (5) industrial application.
Statistical Approach to Developing a Performance Monitoring Program
Authors: Rudland David L. , Widrevitz Dan
Published: November 2023

Inservice inspection (ISI) of passive nuclear components can effectively ensure that aging-related degradation is managed and mitigated throughout the life of a nuclear reactor. However, the basis for the Code-required inspection interval, e.g., typically 10-years, is not clearly documented. Additionally, inspection programs for new and advanced reactors may not be compatible with the inspection methodology used by the current fleet light water reactors, and therefore other methods may be needed. Over the last several years, the U.S. Nuclear Regulatory Commission has approved plant-specific extensions to in-service inspection intervals with a basis that includes operational experience and risk-informed arguments. In some cases, requests have been made to extend this interval to the end of licensed life of the plant, resulting in possible inspection elimination. This paper describes some considerations for the performance monitoring needed to ensure that the analyses supporting inspection interval extensions remain valid throughout the operating life of the associated components. Further, special challenges associated with the development of performance monitoring strategies are discussed. While there may be many options in developing a robust performance monitoring program, this paper presents some initial thoughts on how statistical methods may be used to develop some aspects of a performance monitoring program that can be used in conjunction with detailed analyses to justify the extension of inservice inspection intervals, while continuing to ensure plant safety.
Evaluation of FMC/TFM Performance for Volumetric NDT to Field Piping Welding
Authors: Nakamura Shohei , Sakir Mohd Helmy , Rozikin Nuurul Akhyar , Saniman Muhammad Nur Farhan
Published: November 2023

Ultrasonics (UT) is a volumetric Nondestructive Examination (NDE) method widely used all over the world and across various industries and has seen rapid improvement. One of the latest UT techniques, Full Matrix Capture / Total Focusing Method (FMC/TFM), shows great potential for piping welding NDE. This study compared FMC/TFM with Phased Array UT (PAUT) and found that FMC/TFM is superior for piping welding NDE and has a wider application range than PAUT. Moreover, this study also investigated suitable equipment parameters for performing inspections more efficiently and precisely. As a result, probes with at least 32 elements should be used for optimal image resolution and flaw detection. When a probe with a small footprint [L23*W16*H20 (mm)] was used, it could be applied for both sides of transverse welds of piping larger than or equal to a nominal pipe size (NPS) of 8, even for pipe-to-elbow connections, since FMC/TFM requires a shorter offset distance from the probe to the weld toe than PAUT does. In conclusion, this study found that FMC/TFM has a great potential to be used instead of PAUT as a volumetric NDE technique for piping welding inspection.
Further Investigation of the API 579-1/ASME FFS-1 KPECL Stress Intensity Factors
Authors: Altstadt Steven
Published: November 2023

The API 579-1/ASME FFS-1 2021 Fitness-For-Service (API 579) stress intensity factor solution for a plate with an embedded crack, infinite length, through-wall fourth order polynomial stress distribution (KPECL) was further investigated. The new findings presented in this paper are built upon the findings and proposed API 579 updates presented in 2022. Current API 579 guidance is that the KPECL solution can be used as an acceptable approximation for a cylinder with an embedded crack, circumferential direction, 360 Degree, through-wall fourth order polynomial stress distribution (KCECCL) when the ratio of the internal radius (Ri) to wall thickness (t) is greater than or equal to five, Ri/t ≥ 5. API 579 also makes the same recommendation for the corresponding case of a cracked sphere geometry (KSECCL). As part of the investigation, KCECCL influence coefficient values and KSECCL influence coefficient values were calculated for Ri/t = 5 and are presented in this paper. A comparison of the new results to the previously reported KPECL influence coefficients are presented. For both curved geometries, it was determined that the KPECL influence coefficients proposed in 2022 are reasonable approximations for Ri/t ≥ 5, however a few scenarios were identified where this practice may under-predict the stress intensity factor by a few percent. The new influence coefficient values are recommended as options for fitness for service assessments that involve either the KCECCL scenario or the KSECCL scenario with Ri/t ≥ 5.
Age-Hardened Nickel-Base Alloys for Power Piping
Authors: deBarbadillo John
Published: November 2023

Age-hardened nickel-base alloys began to be seriously considered for power piping in the late 1990’s in the European Thermie project to develop materials technology for Advanced Ultra-supercritical (AUSC) coal-fired power boilers. It was recognized at that time that conventional ferritic and austenitic boiler tube would require unrealistically large wall thickness at the temperatures and pressures specified for AUSC. Only age hardened nickel-base alloys appeared to provide the required combination of creep strength, hot corrosion and oxidation resistance, and weldability. Over the next decade projects were initiated in many countries to characterize new and legacy alloys for this application. The results of this work were widely shared internationally and served as a material data basis for newer advanced energy technologies such as supercritical CO2, Gen 3 concentrating solar, and Gen 4 nuclear. Over the past decade full-scale component demonstrations and pilot plants designed for operation at or above 700°C have been constructed and operated in test mode. This paper summarizes achievements to date using primarily examples for UNS N07740 but with reference to published data on similar alloys. Specific challenges for future widespread use of these alloys are defined.
Simplified Method for Seismic Assessment of Buried Pipeline With Local Wall Thinning
Authors: Onuki Shoma , Mitsuya Masaki
Published: November 2023

This study proposed a seismic assessment formula for pipes with wall thinning subjected to cyclic axial loading assuming seismic motion. Cyclic loading experiments using pipes with wall thinning were conducted to study the deformation and failure behavior. Two deformation modes were observed: buckling and bending deformations at the point of wall thinning. In the buckling mode, the buckling deformation at wall thinning progressed in accordance with the number of cyclic loading; finally, plastic instability occurred due to elephant foot buckling at full pipe cross-section. In the bending mode, the bending deformation at wall thinning was repeated by cyclic loading. Subsequently, fatigue cracking initiated and penetrated the remaining pipe thickness at wall thinning. Based on the deformation behaviors at wall thinning during cyclic loading, simplified seismic assessment formula was proposed. The proposed formula can easily evaluate the seismic performance of the pipe with wall thinning against seismic motion. The formula was validated using finite element analysis for different wall thinning sizes and pipe properties. In addition, based on the proposed formula, the assessment curves were plotted for allowable size of the wall thinning against seismic motion. The formula can be used to formulate standards and assess the safety of pipes with wall thinning that are subjected to seismic motion.
Proposal of Revision of Upper Limit of Hydrostatic Test Pressure in KD-236 and KT-312.3 of ASME Section VIII Division 3
Authors: Terada Susumu
Published: November 2023

Regarding the upper limit of hydrostatic test pressure, KD-236 of Section VIII Division 3 prescribes that an elastic-plastic analysis using an elastic-perfectly plastic material model with the specified yield strength at test temperature shall be performed on a vessel. The reason why such material model shall be used for hydrostatic test criteria in KD-236 is to match the analysis to the criteria for the upper limit of the hydrostatic test pressure in KT-312. The upper limit of the hydrostatic test pressure for an open-end and closed-end cylindrical shell was based on general yielding using Gangling’s and Nadai’s equations with yield strength and design factor Kut for the upper limit of hydrostatic test pressure in KT-312. Especially for SA-372 Gr. E Class 70, the ratio of burst pressure to the upper limit of the hydrostatic test pressure becomes more than 1.5. There is a large amount of strain hardening which occurs in the deformation process of this material and the perfectly plastic limit makes it impossible to utilize the materials in a practical manner. The new hydrostatic test criteria for elastic-plastic analysis using an elastic-plastic stress-strain material model are proposed to reduce this conservativeness, instead of an elastic-perfectly plastic material model in current KD-236. The new load factor for the upper limit of the hydrostatic test should be 1.25 since the maximum equivalent plastic strain is less than 5 % and the shake-down on the inside surface is achieved by the subsequent design pressure. The revisions of KD-236 and KT-312 were proposed. The background of these revisions is described in this paper.
Assessment of the Need to Consider HAZ Properties as Part of RPV Integrity Management
Authors: Kirk Mark , Erickson Marjorie , Long Elliot J.
Published: November 2023

A heat-affected zone (HAZ) forms adjacent to any weld; it is the region of the base metal that has not melted but rather has had its properties affected by the heat of welding. The physical size of the HAZ depends on the welding heat input and section thickness; generally, reactor pressure vessel (RPV) structural welds have a HAZ that extends into the base metal by ≈3 mm. Due to the complex microstructures in the HAZ, presence of residual stresses, and potential for undetected and (therefore) unrepaired indications HAZ regions have long been identified as a potential Achilles heel of component structural integrity. Consequently, HAZ toughness properties have long been monitored as part of RPV surveillance and their consideration in structural integrity assessments has been required by ASME Code and regulations.

Considerable anecdotal evidence has accumulated over time suggesting that the toughness properties of the HAZ are, if anything, superior to that of the adjacent base metal and weld. As such, continued monitoring and assessment of these properties may no longer be needed to ensure the operating safety of RPVs. In this paper we provide a review of existing HAZ requirements in several countries and a comprehensive analysis of HAZ data in comparison with companion base and weld metal data. This analysis demonstrates that the HAZ material embrittles at a rate well modeled by existing predictive models for base metals, albeit with more uncertainty. This result suggests that in plants where the weld metal is more sensitive to the effects of embrittlement than the base metal (and, by association, the HAZ), the HAZ can never have the highest T41J value after embrittlement. For plants in which the base metal is more sensitive to the effects of embrittlement than the weld metal the only way for the HAZ transition temperature to exceed that of the base metal is via data scatter. Of the surveillance data examined the T41J of the HAZ exceeds that of the base metal less than 1% of the time.
Fracture and Fatigue Crack Growth Performance of a Vintage X60 Pipeline Material in Gaseous H2 and Comparison With Wet Sour Service
Authors: Bezensek Bostjan , Hopkin Sarah , Martin Tom , Guijt Wim
Published: November 2023

Fracture toughness and fatigue crack growth testing was performed on the parent and weld microstructures of a vintage offshore API 5L X60 grade pipeline material to assess the impact of various partial pressures of gaseous H2. Fracture toughness values were found to reduce compared to the in-air values as expected, and fatigue performance was consistent with published literature for ΔK above 5 MPa√m. At ΔK below 5 MPa√m the fatigue crack growth curve is higher than predicted, which is suspected to be driven by time dependent sustained cracking mechanism. This phenomenon appears to be a function of the applied pressure (i.e. the max stress intensity factor) and the microstructure. In comparison to the wet sour service the gaseous hydrogen appears less detrimental to the material performance at low partial pressure H2 (representative of a 10% blends) and becomes similar to the NACE Region 2/3 with low pH sour performance at higher partial pressures of H2.
Welding, Repair and Local Post Weld Heat Treatment Residual Stresses
Authors: Billon François , Tejc Josef , Krakovsky Andrej , Vanek Mojmir , Moreau François
Published: November 2023

The study presented deals with an industrial case and relates to the calculation of the residual stresses in a butt weld of two shells of large diameter, high thickness and great length constituting part of pressure equipment.

After completion of the weld, it can be repaired if unacceptable defects are detected and then stress relieved by a local heat treatment.

The objective of the study is therefore to calculate the residual stresses after completion of the weld, then the residual stresses after repair and finally the residual stresses after the local heat treatment.

The residual stresses at the different stages are carried out using finite element modeling of the assembled elements and by digital simulation of the production of the weld and its repairs by metal deposition in multiple passes.

The local stress-relieving post-treatment is carried out at an average temperature of 615°C in the weld and according to a well-defined thermal cycle.

The residual stresses at the end of the simulation are calculated by using the laws of behavior of the materials in plasticity and in creep and by taking account of the longitudinal thermal gradients generated by the locally heated zone.

The scientific calculation tool used is SYSWELD [1], dedicated specifically to welding and the total digital simulation is carried out continuously, successively welding, repair(s) and PWHT. Stress calculations are carried out with the viscoplastic laws of the materials involved and the metallurgical transformation laws for the deposited metal.

The expected results are the values and the distribution of the residual stresses at the end of the welding plus repairs simulations and PWHT to evaluate whether they must be considered further in the stress analyzes or not.
CFD Simulation of Gas-Liquid Non-Uniform Erosion in Connection Pipeline of Silicon Tetrachloride Hydrogenation Process
Authors: Shi Jiarui , Chen Sheng , He Meng , Liu Min , Zhu Liyun , Xie Guoshan , Wang Jiangyun
Published: November 2023

Modified Siemens is a main technology in polycrystalline silicon production unit. Their pipes often occur serious droplet particle erosion in the hydrogenation process that causes silicon tetrachloride reaction to trichlorosilane. Droplet particle erosion easily causes hazardous medium leakages, even leading to fire and explosion phenomena and economic losses. A droplet-particle erosion phenomenon happened in connecting pipe between the static mixer and the silicon tetrachloride evaporator of the polycrystalline silicon production unit. This work aimed to accurately analyze the erosion phenomenon position formation caused by simulation. The erosion phenomenon was predicted with the dense discrete particle model (DDPM), coupling into energy-minimization multi-scale (EMMS) drag model to improve the accuracy of non-uniform gas-liquid flow distribution. Comparison with simulation dates is conducted regarding the gas-droplet drag model, droplet wall specularity coefficient, atomized droplet size, and hydrogen volume fraction. The results indicated that the simulation approach with drag modified and suitable parameters selected has a good agreement with industrial phenomenon data. The different atomized droplet particle sizes directly affect the erosion location, the predicted position with 100μm droplet size is in accord with actual phenomena. The flow rate with the increase of hydrogen volume fraction also affects the erosion location and rate. In addition, the erosion phenomenon is due to poor atomization and a high gas-liquid flow rate.
Exploration of Design, Manufacture and Maintenance of Pressure Vessels in China Under Background of the Internet
Authors: Chen Xuedong , Fan Zhichao , Xu Shuangqing , Hu Jiushao , Zhu Jianxin
Published: November 2023

Pressure vessel is a kind of high-end equipment with a large quantity and wide applications, showing the potential hazard of leakage and explosion. In the past decade, the Chinese government has put forward clear requirements for the digitalization, networking and intelligentization of high-end equipment manufacturing under background of the Internet. Since the beginning of this century, Chinese scientific and technical workers have carried out engineering practice and exploration in the design, manufacturing and maintenance of pressure vessels based on life-cycle risk control in view of the prominent problems of high failure probability and many explosion accidents in China. The problems have been basically solved including the complex failure modes identification, inspection and monitoring, safety diagnosis and failure prevention under the extreme service environment and equipment size. The experience gained from in-service inspections and failure accidents analyses has been fed back to the early stage of pressure vessel design and manufacturing. The technical system of risk-based pressure vessel design, manufacturing and maintenance has been established. The standardization, softwareization and digitalization of the structural design, manufacturing process optimization and risk assessment of pressure vessels have been preliminarily realized, and good results have been achieved. However, in the face of the long-term safety service requirements of important pressure vessels in the development and utilization of new energy in the future, there are still problems such as unclear failure modes of some equipment, insufficient collaborative risk control of pressure vessels due to insufficient information and data interconnection in the optimization of material properties, manufacturing process, inspection, operation and maintenance. In this paper, it is proposed to develop an integrated cloud service platform in China for risk-based pressure vessel design, manufacturing and maintenance around 2025. A unified database architecture and risk influencing factors knowledge base will be established. The application problems of key technologies will be broken through such as cross-stage risk identification and control, cross-software multi-source heterogeneous data fusion, microservice architecture design, generative design, and digital twins in pressure vessels. The cloud service platform will integrate the services such as risk assessment, structural design, strength analysis, safety diagnosis, remaining life prediction, generative design, and digital twins, etc. It will provide support for the safe, green and intelligent development of high-end pressure vessels in the process industries.
Research and Application of a Dynamic Risk Management System for the Petrochemical Unit in Extended Service
Authors: Han Zhiyuan , Li Jun , Liu Juanbo , Xie Guoshan , Kang Haoyuan
Published: November 2023

A large number of pressure vessels and pipelines in China’s refining and chemical industry will soon enter the extended service period (more than 20 years). It is estimated that by 2025, the growth rate of pressure vessels in extended service will increase from the current 10 thousand units/year to 100 thousand units/year, thus the safety of these aging equipment is the focus of current attention. It is necessary to accurately evaluate and early warn the failure risk of these equipment, especially considering the complex influences, high uncertainty and suddenness of the failure in long-term service. On the other hand, the risk management methods of pressure vessels and pipelines are well-established based on API 571, API 581 and API 584. The commercial software is also developed for risk assessment and integrity management by some institutions and companies. However, at present, the risk assessment and control of equipment in refining and chemical industry are mainly based on the static data and static assessment methods, which have little correlations with the dynamic data from equipment operation and corrosion inspection. Based on the above requirements of corrosion management and risk control for the equipment in extended service, this study developed a dynamic risk management method and system, included the dynamic data interaction with Laboratory Information Management System (LIMS), Distributed Control System (DCS) and corrosion inspection systems, the damage identification diagnosis, the dynamic risk and residual life assessment, and the application of Integrity Operating Windows (IOWs). This paper also introduces the application of the system in crude distillation units as an example to explain the method in detail. The results show that the dynamic risk management system can effectively identify the real-time risks of aging equipment and give early warning to state parameters, which is important to avoid the failure of aging equipment.
Fretting Wear Prediction of an Energy-Based Model for Heat Transfer Tube in Steam Generators
Authors: Guo Kai , Wang Boyao , Zhang Hongsheng , Yu Meiqi , Tan Wei
Published: November 2023

The heat transfer tubes of steam generators can be vibrated by the fluid, which causes impact and sliding between tubes and the supports and leads to the fretting wear of tubes. Fretting wear is an unavoidable damage of heat exchanger tube bundles. In practical engineering, it is necessary to predict the wear of the heat exchanger tube, especially in steam generators. At present, the most widely-used fretting wear prediction model is the Archard model, which can not consider the effect of impact in wear process. In fact, the role of impact in wear can not be ignored. Based on an energy method, an impact-sliding prediction model is proposed. And a finite element calculation program is established, and the prediction results of the Archard model and the energy-based model method are calculated respectively. The results show that the prediction of impact sliding wear prediction model based on energy loss can adapt to more conditions, and is better than Archard model in the wear prediction of steam generator tube bundles. The model is promising in prediction of the fretting wear of the steam generator and ensure the safe operation of the equipment.
Very Low Cycle Fatigue Evaluation of Pipe Elbow and Experimental Validations: I- Quasi-Static Cyclic Loading Test
Authors: Lee Jong-Min , Kim Yun-Jae , Song Hyun-Seok , Kim Jin Weon
Published: November 2023

In this paper, pipe elbow under cyclic in-plane bending loads was evaluated using strain-based evaluation methods. For strain-based evaluation methods, acceptance criteria for local failure presented in ASME BPVC Sec. VIII and the void growth/shrinkage model were considered. The void growth/shrinkage model is evaluation model that incorporates the void growth effect to the acceptance criteria presented in ASME BPVC Sec. VIII. For the validation of evaluation models, predicted failure cycle of pipe elbow was compared with experimental results. The ASME BPVC Sec. VIII method gives very conservative results. The reason of this conservatism is that the void shrinkage effect under compressive loading is not considered. Therefore, the void growth/shrinkage model incorporating void shrinkage effect significantly improving evaluation results compared to result of ASME BPVC Sec. VIII, and crack initiation cycle can be predicted much closer but still smaller than the experimental result.