14,888 results on '"Pressure vessels"'
Search Results
2. Design of a Type-III hydrogen pressure vessel with an elliptical dome for stress reduction in the composite layer.
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Abbas Hamdani Syed, Zargham, Che, Jia-le, and Chang, Seung-Hwan
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PRESSURE vessels , *STRESS concentration , *FRACTURE mechanics , *LAMINATED materials , *ELLIPSOIDS - Abstract
Different elliptical dome shapes were evaluated to assess the impact of dome geometry on the stress distribution in the composite laminates of a Type-III pressure vessel with a consistent winding pattern. The study focused on three elliptical dome configurations, all sharing the same height and width, but with slope m ranging from 1.4 to 3.4, to determine the optimal conditions for minimizing stress. The composite thickness at the dome region, based on the slope m was estimated, and the in-plane stress distributions were calculated. Possible material failure was then assessed using the maximum stress criterion. The results demonstrated that the elliptical dome geometry effectively reduced the stress distribution compared to the conventional hemispherical dome. [Display omitted] • Investigates elliptical dome configurations for pressure vessel. • Analyses effect of dome geometry changes on resisting internal pressure. • Assesses stress distributions along the fibre and in-plane transverse directions. • Demonstrates effective management of stress concentrations in critical areas. [ABSTRACT FROM AUTHOR]
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- 2025
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3. Visualized Analysis of Mapping Knowledge Domains for Oil and Gas Pipelines Failure Research.
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Xu, Lei, Xu, Yong, Wang, Yunfu, Xiong, Wei, Yu, Pengfei, and Liu, Jian
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FAILURE analysis , *GAS engineering , *PRESSURE vessels , *OIL fields , *BAYESIAN analysis , *PETROLEUM pipelines , *PIPELINE failures - Abstract
Failure analysis is a vital technique that is intended to strengthen the integrity management of oil and gas pipelines. The significance is to reduce economic losses and avoid or minimize major failure incidents. The aim of this study is to use bibliometric methods to research 2,533 papers retrieved from the Web of Science database spanning from 2004 to 2023. The analysis conducted using VOSviewer, focused on temporal trends, geographic distribution, major organizations, leading authors, journal co-citations, and literature co-citations. The objective is to uncover research hotspots and frontiers, providing insights to advance failure analysis and prevention techniques. The findings revealed a substantial surge in the number of papers related to failure analysis, escalating from 16 in 2004 to 190 in 2023, indicating an overall exponential growth trend. This growth has been most pronounced over the past 8 years. Noteworthy contributors to this field include China, the USA, Canada, England, and Iran, with Iran, Australia, and Italy exerting significant impact. In addition, the top three research producers are all from institutions or universities located in China. The journals Engineering Failure Analysis, International Journal of Pressure Vessels and Piping, and Journal of Loss Prevention in the Process Industries exhibit the highest publication numbers. Significantly, Journal of Loss Prevention in the Process Industries and Gas Science and Engineering emerge as influential and highly regarded publications within this field. The study revealed that while the foundational theory and research framework in oil and gas pipeline failure have crystallized, a plethora of research directions and cutting-edge branches continue to emerge. Notably, the study of failure possibilities and behavior through Bayesian networks, failure characterization analysis, and finite element methods have emerged as the primary development directions and research hotspots. In terms of innovation, the application of bibliometric methods has enhanced the capacity to handle extensive literature databases and conduct network analyses. This study furnishes a theoretical foundation and guidance for the advancement of failure analysis and prevention techniques in the field of oil and gas pipelines. [ABSTRACT FROM AUTHOR]
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- 2025
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4. Heat Treatment Optimisation of Electron Beam Welded Reactor Pressure Vessel Steel.
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Bruce, Kirstie, Taylor, Mark, Fellowes, Jonathan W., Gyves, Ken, Li, Kexue, Moore, Katie L., Burling, Luke D., Francis, John A., and Pickering, Ed J.
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ELECTRON beam welding ,FILLER metal ,HEAT treatment ,PRESSURE vessels ,WELDING - Abstract
Electron beam welding (EBW) is a promising technology for the joining of large steel components such as pressure vessels. Notably, EBW does not use a filler metal, meaning that the weld and parent material (PM) should have the same composition. Accordingly, it may be possible to homogenise microstructure and properties across the weld given a suitable post-weld heat treatment (PWHT), essentially making the weld 'disappear'. To investigate this possibility, three different PWHTs were applied to an SA508 Grade 4N weld. A stress-relief PWHT only had a relatively minor impact on the variations in microstructure and hardness across the fusion zone (FZ), heat-affected zone (HAZ) and PM versus the as-welded state, and compositional microsegregation in the FZ was unchanged. Hardness was successfully homogenised across the parent and weld in heat treatments involving a traditional 860 °C austenitisation, quench and temper, but compositional microsegregation persisted in the FZ. The addition of a homogenisation step at 1200 °C eliminated this microsegregation, with the weld area only remaining visible owing to the presence of compositional banding in the PM. However, homogenisation also led to the formation of undesirable prior austenite grain structures following subsequent re-austenitisation at 860 °C. Nevertheless, the application of PWHTs involving a full re-austenitisation seems promising for future applications. [ABSTRACT FROM AUTHOR]
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- 2025
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5. Feasibility study of carbon-fiber reinforced polymer linerless pressure vessel tank.
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R, Sundharesan and JV, Sai Prasanna Kumar
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FATIGUE limit ,THERMAL expansion ,AEROSPACE engineering ,MANUFACTURING processes ,TENSILE tests ,PROPELLANTS - Abstract
Composite pressure vessels are used in aerospace engineering for storing fluids such as propellants, nitrogen, and oxygen. They are also used in life-support systems, High-performance pressure suits for astronauts, Helium Tanks for Balloons and Airships. Among many types of composites, Carbon fiber composites uses have been increasing due to its high strength to weight ratio, high thermal expansion, corrosion, fatigue and impact resistance and design flexibility. In order to improve the volume of the pressure vessel, the liner-less concept is tried. This increased volume efficiency is crucial in aerospace applications where space is at a premium and maximizing storage capacity within limited dimensions is important. Not only the volume efficiency, but also the Reduced Permeability Concerns, Enhanced Durability and Longevity, better thermal continuity and simplified manufacturing process make this research significant in the area of pressure vessel. This research paper deals with the fabrication and development of a cylinder without a lining. The test sample was subjected to several tests: tensile test, impact, shear test (3P Bending), leak test and Pressure test. The test sample was capable of withstanding 20 Bars without failure. The numerical results were also performed and compared with the experimental results. The difference was only 3%. Unsymmetrical dimethyl hydrazine (UDMH) AND red-fuming nitric acid can both be stored in this cylinder (RFNA). Unlike traditional composite overwrapped pressure vessels, the liner-less composite tanks rely completely on the composite shell to act as a permeation barrier as well as handling all pressure and environmental loads. The absence of a liner eliminates the potential for delamination or failure at the interface between the liner and the composite material. [ABSTRACT FROM AUTHOR]
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- 2025
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6. A comprehensive case study to the implicit and explicit approach in finite element analysis.
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Huner, Umit, Irsel, Gurkan, Bekar, Umut, and Szala, Miroslaw
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ELASTICITY ,PRESSURE vessels ,FINITE element method ,BEND testing ,DEFORMATIONS (Mechanics) - Abstract
The primary aim of this study is to conduct a comprehensive comparative evaluation of implicit and explicit finite element solution methodologies employed in structural analysis. This research examines the characteristics and performance differences between these two approaches, using two diverse case studies as illustrative examples. The FEM solution was performed nonlinearly by defining the linear elastic and plasticity properties of the material. The first case study focuses on a three-point bending test of a beam subjected to a slow deformation rate, while the second case study examines the damage mechanics of a pressure vessel experiencing a high deformation rate. It was found that the implicit solution method operates under the premise that displacement is independent of time, allowing for a more stable analysis in certain scenarios. On the other hand, the explicit method inherently incorporates time as a variable, making displacement a function of time. Once a solid understanding of the system's response is established, transitioning to explicit methods for more dynamic scenarios can lead to a more comprehensive and effective resolution of complex engineering problems. By carefully selecting the appropriate analysis method based on the specific characteristics of the loading conditions and the nature of the forces involved, engineers can optimize their simulations and enhance the reliability of their results. [ABSTRACT FROM AUTHOR]
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- 2025
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7. Hazard, exposure, fragility, and damage state homogenization of a virtual oil refinery testbed for seismic risk assessment.
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Melissianos, Vasileios E, Karaferis, Nikolaos D, Bakalis, Konstantinos, Kazantzi, Athanasia K, and Vamvatsikos, Dimitrios
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GROUND motion ,PRESSURE vessels ,PETROLEUM ,REDUCED-order models ,PETROLEUM refineries ,EARTHQUAKE resistant design - Abstract
A virtual mid-size oil refinery, located in a high-seismicity region of Greece, is offered as a testbed for developing and testing system-level assessment methods due to direct impact from seismic shaking and without considering geohazards, such as liquefaction and surface faulting. Its characterization is offered in a dedicated repository (https://doi.org/10.5281/zenodo.11419659) and it comprises (a) a comprehensive probabilistic treatment of seismic hazard tied to an open-source seismological model; (b) a hazard-consistent set of ground motion records; (c) a full geolocated exposure model with all pertinent critical assets, namely tanks, pressure vessels, process towers, chimneys, equipment-supporting buildings, and a flare; (d) the corresponding record-wise asset demands and summarized fragilities derived via nonlinear dynamic analyses on reduced-order numerical models. Background information is provided on all refinery assets to delineate their role in the refining process. Furthermore, an explicit homogenization of the damage states is proposed, translating them from the asset level to the refinery system level considering the importance of each asset on the overall operational and structural integrity of the refinery. The results can form the basis of any follow-up study that seeks to characterize the effects of cascading failures (fires, explosions), mitigation measures, seismic sequences, and operational constraints on the functionality, risk, and resilience of refining facilities. [ABSTRACT FROM AUTHOR]
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- 2025
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8. Optimizing performance of hybrid fiber reinforced overwrapped pressure vessel.
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Warkina, Reta and Regassa, Yohannes
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PRESSURE vessels , *STRESS concentration , *FIBER orientation , *STRAINS & stresses (Mechanics) , *FINITE element method - Abstract
Composite overwrapped pressure vessels (COPVs) offer significant weight advantages over traditional all-metal vessels particularly in industries like aerospace, automotive and pharmaceutical, but pose unique challenges in mechanical design, fabrication, and testing. Despite their benefits, COPVs are susceptible to stress rupture failure, which can lead to catastrophic consequences during operation. This failure mode is not fully understood, with burst pressure-induced extreme stress concentrations and dynamic loading primarily contributing to rapid deformation and strain. To address these concerns, a comprehensive investigation was conducted, focusing on optimizing and examining the effects of optimum winding angle and lay-up pattern configuration on burst pressure in vessels under internal pressure. Finite element modeling analyzed the burst pressure behavior of COPVs with a 4 mm thick aluminum core cylinder and varying layers of carbon/fiber epoxy, each with a constant thickness. ABAQUS composite modeler generated 18 COPV models with carbon fiber/epoxy plies, ensuring uniform thicknesses while exploring different fiber orientations. The effects of ply stacking sequence were analyzed through finite element analysis for all models, comprising varying layers with uniform thicknesses. Attention was paid to failure criteria, methodically evaluating the burst strength of the Al/CFRPC COPVs This exhaustive analysis yielded an optimal COPV design profile characterized by a precisely calibrated ply stacking sequence of [24.50, −24.50] PP winding pattern and six (6) arranged layers. The stress-strain distribution analysis of the Composite Overwrapped Pressure Vessel (COPV) revealed both a uniform distribution of stress across its surface and extreme stress concentration, particularly peaking towards the polar boss region. This concentration is discernible due to variations in ply thickness induced by the overwrapped fiber orientation. This investigation provides valuable insights for optimizing COPV design and enhancing its performance and reliability in various applications. [ABSTRACT FROM AUTHOR]
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- 2025
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9. 大规模氢气罐区安全泄放量计算方法研究.
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王报春, 丁梅峰, 徐兴文, 李文龙, 姚建军, and 常征
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HYDROGEN storage ,ISOBARIC processes ,HYDROGEN as fuel ,PRESSURE vessels ,COMPRESSED gas ,STORAGE tanks - Abstract
Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2025
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10. Aneurysm dome and vessel pressure measurements with coiling, stent assisted coiling and flow diversion.
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Becker, Timothy A., Lewis, Kailey L., Berns, Holly F., Robertson, Sophia E., Clark, Wyatt E., Wells, Jesse C., Alnajrani, Mohammed K., Rapoport, Christopher, Barhouse, Patrick, Ramirez-Velandia, Felipe, Filo, Jean, Young, Michael, Muram, Sandeep, Granstein, Justin H., and Ogilvy, Christopher S.
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INTRACRANIAL aneurysms , *SHEAR flow , *ENDOVASCULAR surgery , *PRESSURE vessels , *BALLOON occlusion - Abstract
Background: Variability in long-term endovascular treatment outcomes for intracranial aneurysms has prompted questions regarding the effects of these treatments on aneurysm hemodynamics. Endovascular techniques disrupt aneurysmal blood flow and shear, but their influence on intra-aneurysmal pressure remains unclear. A better understanding of aneurysm pressure effects may aid in predicting outcomes and guiding treatment decisions. Methods: Medium and large aneurysm models with intramural pressure taps on the dome and parent artery were designed and 3D-printed with vessel-like physical properties from UV-cured materials. The models were connected to a comprehensive flow system consisting of a pulsatile pump and a viscosity-matched blood analog. The system provided physiological pressure and flow control. Real-time pressures were recorded in the aneurysm dome and parent artery during initial placement of coils, stents, flow diverters, and temporary balloons under simulated surgical conditions. Coiling, stent-assisted coiling, and flow diverter placement were performed in both aneurysm sizes. Temporary balloon placement was performed in a large aneurysm model. Results: Coiling resulted in 24–30% packing density and diminished intra-aneurysmal flow. Flow diverter placement reduced intra-aneurysmal flow with near complete flow interruption after placement of three consecutive devices across the aneurysm neck. Compared to untreated controls, real-time pressure measurements during coiling and flow diversion showed minimal changes (< 5%) in intra-aneurysmal pressures. Temporary balloon occlusion blocked the parent artery, increasing the pressure proximal to the site of occlusion (by 9%), and reducing the pressure distally (by 14%). This maneuver also dampened intra-aneurysmal pressure to the average distal vessel pressure measurement. Positive control aneurysm models were 3D-printed with a sealed, "healed" neck. These controls verified a sealed neck eliminates intra-aneurysmal pressure. Conclusion: Findings quantified minimal changes in intra-aneurysmal pressure during and immediately post-coiling and flow diversion. Intra-aneurysmal flow disruption alone has negligible impact on intra-aneurysmal pressures. [ABSTRACT FROM AUTHOR]
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- 2025
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11. Forging-Submerged Arc Additive Hybrid Manufacturing of the Mn-Mo-Ni Component: In Situ Reheat Cycles Inducing the Homogenization of the HAZ Microstructure.
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Chi, Qiang, Hu, Meijuan, Wang, Jun, Yan, Shuai, Xue, Manye, Wu, Shaojie, and Cheng, Fangjie
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SUBSTRATES (Materials science) , *PRESSURE vessels , *HEAT treatment , *THERMOCYCLING , *SORBITOL - Abstract
Forging additive hybrid manufacturing integrated the high efficiency of forging and the great flexibility of additive manufacturing, which has significant potential in the construction of reactor pressure vessels (RPVs). In the components, the heat-affected zone (HAZ, also called as bonding zone) between the forged substrate zone and the arc deposition zone was key to the final performance of the components. In this study, the Mn-Mo-Ni welding wire was deposited on the 16MnD5 substrate with a submerged arc heat source. The in situ reheat cycle effect of the submerged arc heat source on the microstructure and mechanical properties of the HAZ were studied. The results showed that the HAZ underwent four heat treatment processes, including two full austenitizing stages, one high-temperature stage, and continuous low-temperature tempering, which formed a homogenized microstructure in the HAZ and was mainly composed of tempered sorbite (Tempered-S). The HAZ microhardness is around 278.7 HV, which is about 150 HV lower than the microhardness only conducted by one thermal cycle. Furthermore, the effects of preheating the substrate and adjusting the heat inputs on the HAZ were studied. The results indicated that the clustered cementite was precipitated, which destroys the low-temperature impact toughness of the HAZ after preheating. A suitable heat input not only homogenized the microstructure within the HAZ but also promoted the transformation of grains into equiaxed grains. The −60 °C impact toughness of the HAZ was significantly increased from 96.7 J to 113 J. [ABSTRACT FROM AUTHOR]
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- 2025
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12. Design and experimental performance evaluation of high-temperature and high-pressure test platform for deep in-situ fidelity coring tools.
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Wei Huang, Jianan Li, Yang Yang, Zhiqiang Liu, and Delei Shang
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HIGH temperature electrolysis , *PRESSURE vessels , *ELECTROMAGNETIC induction , *EVALUATION , *EXAMINATIONS - Abstract
With the increasing mining depth of mineral resources, the temperature and pressure of the underground environment are also on the rise, which puts forward strict requirements for the performance of fidelity coring tools. To promote the development of such tools, a comprehensive high-temperature and high-pressure test platform for deep in-situ fidelity coring tools was constructed, and its working principle was described in detail. In addition, four key functional modules of the test platform were developed. On the basis of the principle of gas-liquid pressurization and the burst failure criterion of pressure vessel, a mechanical module integrating the functions of pressurization and pressure maintaining was designed. The heating and insulation module was developed by using a U-shaped highspeed heater and electromagnetic induction heating technology. The innovation utilized coil cooling technology to achieve effective cooling and pressure relief. Furthermore, the working performance of the test platform was studied experimentally. The designed test platform could run stably for more than 110 min under test conditions of high pressure and temperature of 140 MPa and 150 °C, respectively, and it could maintain a stable pressure and temperature at 200 MPa and 160 °C for more than 182 min. Under the high pressure condition of 220 MPa, the pressure remained stable within 140 min, without any fluid leakage. Therefore, the test platform designed in this study can provide experimental conditions of high pressure and high temperature for the research of fidelity coring tools, which is of great significance for the accurate evaluation and safe exploitation of deep mineral resources. [ABSTRACT FROM AUTHOR]
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- 2025
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13. Recrystallization Behavior of Computationally Optimized Low‐Alloy Steel at Various Temperatures and Strain Rates.
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Abdullah, Muhammad Raies, Ahmad, Farooq, Rajendren, Vignesh Babu, Peng, Zhen, Qiao, Guanjun, Liang, Fang, and Shah, Syed Sohail Ahmad
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DEGRADATION of steel , *STRAIN rate , *PRESSURE vessels , *PHASE equilibrium , *THERMODYNAMICS - Abstract
The dynamic recrystallization (DRX) behavior of SA508‐III steel, a critical material for reactor pressure vessels (RPVs) normally treated by hot forging, is thoroughly examined in this article. In the investigation, elevated temperatures and the coarsening of metallic phases and carbides are revealed to contribute to the degradation of the steel's strength–toughness relationship. Utilizing computational thermodynamics, the stability of secondary phases, including carbides and brittle inclusions, is simulated to enable precise phase equilibrium calculations and accurate prediction of key mechanical properties such as yield strength, tensile strength, and hardness. These simulations facilitated targeted modifications to the alloy composition to enhance the steel's strength and hardenability under high‐temperature, high‐pressure conditions. In this study, alloy composition and processing parameters within the CALculation of PHAse Diagram framework, utilizing the ThermoCalc and JMatPro software packages, are optimized. In the microstructural investigations conducted under various isothermal deformation conditions (1173–1473 K) and strain rates (0.001–1 s−1), it is demonstrated that DRX mechanisms led to varied grain size developments, with a critical strain rate identified at 0.01 s−1 during high‐temperature deformations. In these findings, significant insights are provided into optimizing the mechanical performance of SA508‐III steel for RPV applications. [ABSTRACT FROM AUTHOR]
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- 2025
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14. Mechanical analysis of cerclage as a treatment for cervical insufficiency.
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Lee, Jihee, Kang, Thomas H.-K., Jeong, Soyeon, Kim, Jeong Sook, and Lee, Soo-Jeong
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UTERINE cervix incompetence , *CERVICAL cerclage , *PRESSURE vessels , *OPERATIVE surgery , *THREAD (Textiles) - Abstract
Background: The primary treatment for cervical insufficiency is cervical cerclage (mechanical support) with vaginal progesterone (biochemical support). Cerclage is a surgical procedure that mechanically increases the tensile capacity of the cervix. Therefore, it is necessary to analyse the effects of cerclage from a mechanical point of view. Purpose: To analyse cerclage techniques based on physical principles and mechanical forces. Methods: We assumed that the cervix is a thin-walled pressure vessel and applied a uniform vertical distribution model, a linear vertical model, and a non-linear vertical distribution model. Results: According to our model analysis, the higher the position of the thread, the thicker the thread used, and the greater the number of threads, the more effective the confining force on the suture, when performing a cerclage. Conclusion: It is necessary to provide an appropriate cerclage for each patient based on these mechanical characteristics, in addition to considering the risks and benefits and biochemical interactions of the cerclage. [ABSTRACT FROM AUTHOR]
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- 2025
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15. The Effects of Applying the Tribological Compound TZ NIOD - reversing wear.
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Harrer, Philipp, Svetov, Dmitrii, Eisner, Patrick, and Lackner, Maximilian
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PRESSURE vessels ,TRIBOLOGY ,TIME pressure ,AIR compressors ,FRICTION - Abstract
TZ NIOD is a complex mixture of silicate material powder, to mix with lubricant and apply to moving parts of a device under operation to improve its tribological properties. It reaches worn surfaces and highly loaded friction points to react with the material creating a modified surface layer. Empirical analyses with TZ NIOD applied to used piston air compressors required a down time of only 60 minutes and resulted in reducing the average power consumption per pressure vessel filling cycle by 20.7 W (-7.8 %) and reducing the average filling time of the pressure vessel by 3.9 seconds (-5.1 %). [ABSTRACT FROM AUTHOR]
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- 2025
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16. Mapping the Knowledge Domain of Pressure Vessels and Piping Fields for Safety Research in Industrial Processes: A Bibliometric Analysis.
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Mei, Ting, Tong, Chaozhen, Tong, Bingrui, Zhu, Junjie, Wang, Yuxuan, Kou, Mengyao, and Liu, Hui
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PRESSURE vessels ,INDUSTRIAL safety ,CITATION analysis ,NUCLEAR engineering ,BIBLIOMETRICS - Abstract
With the rapid advancement of modern industries, pressure vessels and piping have become increasingly integral to sectors such as energy, petrochemicals, and process industries. To grasp the research and application status in the field of pressure vessel and piping safety, 670 publications in the Web of Science core database from 2008 to 2024 were taken as data samples in this paper. The knowledge mapping tools were used to carry out co-occurrence analysis, keyword burst detection, and co-citation analysis. The results show that the research in this field presents a multidisciplinary and cross-disciplinary state, involving multiple disciplines such as Nuclear Science and Technology, Engineering Mechanics, and Energy and Fuels. The "International Journal of Hydrogen Energy", "International Journal of Pressure Vessels and Piping", and "Nuclear Engineering and Design" are the primary publication outlets in this domain. The study identifies three major research hotspots: (1) the safety performance of pressure vessels and piping, (2) structural integrity, failure mechanisms, and stress analysis, and (3) numerical simulation and thermal–hydraulic analysis under various operating conditions. The current challenges can be summarized into three aspects: (1) addressing the safety risks brought by new technologies and materials, (2) promoting innovation and the application of detection and monitoring technologies, and (3) strengthening the building capacity for accident prevention and emergency management. Specific to China, the current challenges include the safety and management of aging equipment, the effective detection of circumferential weld cracks, the refinement of risk assessment models, and the advancement of smart technology applications. These findings offer valuable insights for advancing safety practices and guiding future research in this multidisciplinary field. [ABSTRACT FROM AUTHOR]
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- 2025
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17. Study on the influence factors of gravimetric hydrogen storage density of type III cryo-compressed hydrogen storage vessel.
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Li, Kexin, Dong, Xueqiang, Wang, Haocheng, and Gong, Maoqiong
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HYDROGEN storage , *THERMAL insulation , *ECONOMIC efficiency , *PRESSURE vessels , *LOW temperatures - Abstract
Cryo-compressed hydrogen storage is a high-density hydrogen storage method, with volumetric hydrogen storage density determined by temperature and pressure. However, the gravimetric hydrogen storage density is influenced by vessel volume, insulation method, operating pressure, operating temperature, and vessel structural dimensions. This study investigates the variations in gravimetric hydrogen storage density under different influencing factors based on the design methods for the liner, winding layers, and insulation layers of cryo-compressed hydrogen storage vessels. The research findings indicate that the optimal pressure must be determined based on the vessel volume. For small-volume vessels, the hydrogen storage density remains relatively unchanged once the pressure reaches 40 MPa, while for large-volume vessels, the best performance occurs at pressures between 20 and 30 MPa. Additionally, vessels with a smaller length-to-diameter ratio and a semicircular dome cross-section exhibit superior hydrogen storage performance. Larger volumes and lower operating temperatures favor the increase of hydrogen storage density. Finally, the study analyzes future process improvements to further explore ideal scales and structures that can achieve the DOE's targets and enhance the economic efficiency of hydrogen transportation. • Design methods for hydrogen storage vessels considering pressure and insulation. • The gravimetric hydrogen storage density under different conditions is calculated. • Optimal pressure is influenced by vessel volume and insulation method. • Vessel with a small length-to-diameter ratio and semicircular dome performs better. • The exploration of ideal vessel specifications to achieve the DOE's 6.5% target. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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18. Electrochemical sensing of sodium ions present in bovine serum using 4-tert-butylcalix[4]arene as a receptor.
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Ebenezer Paul, Adrian, Gaur, Gaurav, Al Souwaileh, Abdullah, Wu, Jerry J., and Anandan, Sambandam
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SODIUM ions , *ALKALI metals , *METAL ions , *PRESSURE vessels , *HYPERTENSION - Abstract
The concentration of sodium ions can cause severe imbalances (high pressure on blood vessels, swelling of the muscular tissues, and misfunctioning of the whole nervous system) to the human body when its limits are uncontrolled. Thus, it is necessary to determine the amount of sodium ions present in the blood. Electrochemical sensing is an efficient methodology for detecting lower concentrations of ions even with fewer samples. Calixarenes are one of the supramolecules with a distinctive structure that has a predominant ability to complex with alkali metals. Thus, calixarenes are widely used in the detection of sodium (Na+) ions. Herein, 4-tert-butylcalix[4]arene, the simplest and cheapest calixarene, is used to deduce sodium ion concentration by electrochemical sensing approach. The sensitivity of the 4-tert-butylcalix[4]arene/GCE was 0.35269 μA M−1 and the limit of detection was 0.1 ± 0.06 μM, the lowest range of detection reported for sodium ions through differential pulse voltammetry, which is an accurate analysis. This is because calixarenes can interact with sodium ions efficiently through the hydrophilic OH groups at the lower rim of the calixarene structure. The interaction of Na+ ions with phenolic OH was confirmed by proton NMR titration against NaOH. 4-tert-Butylcalix[4]arene/GCE is adequately selective against various interfering metal ions, and it can also detect sodium ions with high accuracy (recovery range = 99.25–100.01%) in bovine serums. [ABSTRACT FROM AUTHOR]
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- 2024
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19. Fatigue life calculation method for cryo-compressed hydrogen storage vessel.
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Zhang, Fanyuanhang, Yan, Yan, Zhou, Weihao, Xu, Zhan, Zhang, Jiaqiao, and Ni, Zhonghua
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CARBON fiber-reinforced plastics , *FATIGUE life , *FRACTURE mechanics , *HYDROGEN storage , *PRESSURE vessels - Abstract
As hydrogen plays increasingly vital role in the future energy network, storage, one of the essential processes, has attained much attraction. It is necessary to develop efficient methods to assist in designing, manufacturing and evaluating hydrogen storage vessels for different application scenarios and standards. In this work, the theoretical calculation of fatigue life for cryo-compressed hydrogen (CcH 2) storage vessel have been detailed studied. Firstly, the temperature and pressure variation on the vessel liner were calculated under the refueling and discharging cycle. Subsequently, the stress cycling of the fragile winding layer was transformed by elastic-plastic mechanics method. Furthermore, the S–N curve method and residual strength/stiffness theory were used to calculate the fatigue of the winding layer and optimize the fatigue life, respectively. Finally, the rationality of the calculated fatigue life was verified by the comparison with existing research. The results shows that the fatigue life of CcH 2 storage vessel under cryogenic temperature will be smaller than under normal temperature. The optimized calculation of fatigue causes a certain change in the actual fatigue life, which can reach 1% compared to not correcting the fatigue life. The main failure form is transverse fracture of composite materials caused by compression. • Studying the vessel state of the refueling and discharging cycle process. • Studying the stress changes of the winding layer throughout the cycle. • Combing S–N curve, residual strength/stiffness theory to calculate the fatigue. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
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20. Life cycle assessment of pressure vessels realized with thermoplastic and thermosetting matrix composites.
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Mignanelli, Chiara, Bianchi, Iacopo, Forcellese, Archimede, and Simoncini, Michela
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THERMOSETTING composites , *PRESSURE vessels , *ENVIRONMENTAL impact analysis , *FILAMENT winding , *INTERNAL combustion engines , *FUEL cell vehicles - Abstract
Hydrogen has emerged as a promising energy vector for internal combustion engines or fuel cell electric vehicles, offering the potential to significantly reduce environmental impacts. To store and transport hydrogen efficiently, high-pressure type IV tanks produced using carbon fibre-reinforced polymers are typically used. However, composite materials are associated with significant environmental impacts due to their energy-intensive production and challenging recycling processes. To address these drawbacks, thermoplastic matrix composites can be employed as an alternative to traditional thermosetting matrix composites. In this context, the present paper reports a comprehensive life cycle assessment study comparing the environmental impacts of different pressure vessel types for hydrogen transport. A design phase was conducted to define the product's characteristics and provide primary data. Types IV and V vessels produced by filament winding were considered for the environmental sustainability analysis; different scenarios with carbon fibre tows pre-impregnated with both thermosetting and thermoplastic matrix were considered as raw materials (epoxy resin and polyetherimide). Different impact categories were employed to provide a complete vision of the scenario's effects on the environment. The analysis showed that the type V pressure vessel with a thermoplastic matrix composite is the most environmentally friendly option with life cycle impacts equal to 2568.5 kg CO₂ eq vs. 3797.7 kg CO₂ eq for the epoxy/towpreg type IV vessel and 3462.1 kg CO₂ eq for the epoxy/towpreg type V vessel. This impact reduction is due to lower material use due to the absence of an internal liner and the recyclability of the thermosetting matrix towpregs. [ABSTRACT FROM AUTHOR]
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- 2024
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21. Application of Miniature Specimens for Off-Center Tension Aimed at Determination of Fracture Toughness of Steels of VVER-1000 Reactor Vessel in the Ductile–Brittle Transition Zone.
- Author
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Bandura, A. P., Erak, D. Yu., Zhurko, D. A., Korshunov, M. E., and Bubiakin, S. A.
- Subjects
- *
FRACTURE toughness , *PRESSURE vessels , *STEEL fracture , *NUCLEAR reactor materials , *COMPARATIVE studies - Abstract
The article presents the results of testing miniature CT-0.16 specimens made from materials of the VVER-1000 reactor pressure vessel materials in both unirradiated and irradiated conditions, as well as after thermal aging, treated using the master curve method (ASTM E1921). A comparative analysis of the obtained transition temperatures T0 and results previously obtained for standard three-point bending of PCV specimens was conducted, showing a similarity of these values. An assessment of metal heterogeneity on the basis of the conducted tests according to the SINTAP procedure was carried out, indicating the need to increase the number of CT-0.16 specimens in the test series for the correct determination of the parameter T0. A conclusion was drawn regarding the prospects of using CT-0.16 type specimens for determining fracture toughness of reactor pressure vessel steels in conditions of limited volume of metal. [ABSTRACT FROM AUTHOR]
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- 2024
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22. Preliminary Calculated and Experimental Assessments of the Possibility of Using High-Nickel Steels for Pressure Vessels of Next Generation VVERs.
- Author
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Kuleshova, E. A., Fedotov, I. V., and Kuznetsov, S. P.
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PRESSURE vessels , *HEAT radiation & absorption , *GRAIN size , *STEEL , *COOLANTS - Abstract
The article presents calculated and experimental assessments of the possibility of using Ni-rich RPV steels developed by the JSC NPO Central Research Institute of Machine Building Technology (CNIITMASh) as materials for RPVs of next generation reactors taking into account their structural-phase state, mechanical characteristics, and the possibility of manufacturing a shell with an industrially developed wall thickness. In order to improve service characteristics, it is necessary to apply a complex of measures: change the complex alloying of steels, conduct metallurgical purification from impurities (primarily from phosphorus), and optimize the grain size of castings. The calculation took into account the assumed operating temperature, coolant pressure, strength grade of candidate steels, and their thermal and radiation resistance. [ABSTRACT FROM AUTHOR]
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- 2024
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23. Trends of Structure Degradation of VVER-1000 Reactor Pressure Vessel Steels Determining Their Performance at Lifetimes of over 60 Years.
- Author
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Kuleshova, E. A., Fedotova, S. V., Maltsev, D. A., and Potekhin, A. A.
- Subjects
- *
ATOM-probe tomography , *PRESSURE vessels , *TRANSMISSION electron microscopy , *CRITICAL temperature , *STRUCTURAL steel - Abstract
Changes in the structural state of steels of VVER-1000 reactor pressure vessels (RPVs) at an extended lifetime of 60 years and more were considered. A comprehensive analysis of available experimental data on changes in the structural state of RPV materials under irradiation was carried out. Extended dose dependences of the accumulation rate of radiation-induced structural elements and grain-boundary segregation of phosphorus are presented. The nature of changes in strength characteristics and critical brittleness temperature of RPV materials due to irradiation was shown. A preliminary estimate of the lifetime of RPV steels depending on their nickel content was made basing on the study of trends in the volume density and average size of radiation-induced structural elements, radiation defects, and radiation embrittlement mechanisms. [ABSTRACT FROM AUTHOR]
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- 2024
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24. Design, Analysis, and Testing of a Type V Composite Pressure Vessel for Hydrogen Storage.
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Mikroni, Maria, Koutsoukis, Grigorios, Vlachos, Dimitrios, Kostopoulos, Vassilis, Vavouliotis, Antonios, Trakakis, George, Athinaios, Dimitrios, Nikolakea, Chrysavgi, and Zacharakis, Dimitrios
- Subjects
- *
GREENHOUSE gas mitigation , *PRESSURE vessels , *HYDROGEN storage , *CLEAN energy , *EPOXY resins - Abstract
Hydrogen, as a zero-emission fuel, produces only water when used in fuel cells, making it a vital contributor to reducing greenhouse gas emissions across industries like transportation, energy, and manufacturing. Efficient hydrogen storage requires lightweight, high-strength vessels capable of withstanding high pressures to ensure the safe and reliable delivery of clean energy for various applications. Type V composite pressure vessels (CPVs) have emerged as a preferred solution due to their superior properties, thus this study aims to predict the performance of a Type V CPV by developing its numerical model and calculating numerical burst pressure (NBP). For the validation of the numerical model, a Hydraulic Burst Pressure test is conducted to determine the experimental burst pressure (EBP). The comparative study between NBP and EBP shows that the numerical model provides an accurate prediction of the vessel's performance under pressure, including the identification of failure locations. These findings highlight the potential of the numerical model to streamline the development process, reduce costs, and accelerate the production of CPVs that are manufactured by prepreg hand layup process (PHLP), using carbon fiber/epoxy resin prepreg material. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
25. Mechanical behavior and fracture analysis of the cylindrical component of type‐III high‐pressure composite tanks.
- Author
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Avcu, Adem, Seyedzavvar, Mirsadegh, Boğa, Cem, and Choupani, Naghdali
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- *
ELASTIC modulus , *FRACTURE toughness testing , *FRACTURE toughness , *PRESSURE vessels , *TENSILE tests - Abstract
Highlights This study presents a broad investigation of the mechanical properties and fracture behavior of a type‐III high‐pressure composite tank, with an emphasis on the cylindrical section, which is critical for ensuring the safety and reliability of pressure vessels in various applications. The experimental methods included split disk tensile (SDT), curved compact tension (CCT), and pipe ring notched bending (PRNB) tests, which were used to evaluate the hoop tensile strength, fracture toughness, and critical internal pressure of the cylindrical section under different loading conditions. Finite element analysis was used to complement the experimental findings and predict the failure behavior of this section. The SDT test was performed on samples taken from the cylindrical portion of the pressure tank, and its strength and modulus of elasticity were determined. Using CCT and PRNB tests, the fracture toughness of the studied tank materials was found to be 36.90 and 35.73 MPa√m, respectively. The small difference between these results confirmed the reliability of the tests in determining fracture toughness. Analysis of critical internal pressure versus crack length in the cylindrical section emphasized the importance of crack detection and management for safe operation. Overall, this study provides valuable insights into the mechanical behavior and fracture characteristics of the cylindrical part of high‐pressure composite tanks, which can contribute to their design and performance for enhanced safety and reliability in various industrial applications. Determining the mechanical properties of the composite tank with the SDT test. Characterizing the fracture toughness with CCT and PRNB tests. FE analysis of fracture behavior of high‐pressure composite tank. Providing valuable insights to increase safety and reliability. [ABSTRACT FROM AUTHOR]
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- 2024
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- View/download PDF
26. Effect of hollow glass microspheres on transverse properties of carbon fiber reinforced epoxy composites.
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Tejasvi, K., Sharma, Annu, Ranga, K. V. S., Gurusideswar, S., and Sundar Singh, P.
- Subjects
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DYNAMIC mechanical analysis , *TRANSVERSE strength (Structural engineering) , *FIBROUS composites , *GLASS transition temperature , *PRESSURE vessels - Abstract
Hollow glass microsphere (HGM)—based composites are gaining popularity in materials research due to their ability in altering material characteristics drastically. The current study investigates HGMs filled carbon fiber reinforced epoxy (CE) composites on transverse properties, aiming for aerospace and defense applications mainly in composite pressure vessels. Unidirectional laminates of Carbon/Epoxy with varying HGM percentages (0.2, 0.4, 0.6, 0.8, 1.0 wt. %) were wounded onto a flat‐plate mandrel using a 4‐axis filament winder, along with a baseline sample without HGM for comparison. The glass transition temperature (Tg) and thermal stability were analyzed by carrying out dynamic mechanical analysis and thermogravimetric analysis. The fracture mechanism of the samples loaded under tension was investigated using FESEM. Experimental results indicate reduction in density with increase in HGM content, up to 0.4% HGM there is increase in transverse tensile strength of 25% compared to baseline and further increase in HGM content, decrease trend is observed. 30% decrease in transverse compressive strength is observed compared from baseline to 1.0 wt. % of HGM. No significant change was noticed in the thermal stability and Tg on introduction of HGM. Microscopy images of fractured samples revealed effective physical interaction and dispersion of the HGM within the matrix. Highlights: Transverse mechanical properties are tested to know the influence of HGM filler on filament wound composites.Density of the composite decreases with increase in HGM content.Thermal stability and Tg shows less change on introduction of HGM in composites. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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27. Monitoring and Control System of the Test Facility for Studying the Superconducting Magnets of the Final Focusing System.
- Author
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Kozub, S. S., Ageev, A. I., Antonets, R. V., Orlov, A. P., Stolyarov, M. N., and Vlasov, A. S.
- Subjects
- *
PHYSICAL sciences , *ION accelerators , *PRESSURE vessels , *LIQUID helium , *TEMPERATURE control , *SUPERCONDUCTING magnets , *MAGNETS - Abstract
NRC Kurchatov Institute–IHEP has developed superconducting quadrupole magnets for the final focusing system of heavy-ion beams of the HED@FAIR collaboration of the International Ion and Antiproton Accelerator Facility (FAIR) in Darmstadt, Germany. These quadrupoles should have the unique combination of a large superconducting coil of inner diameter of 260 mm and a high magnetic-field gradient of 37.5 T/m at a magnet operating temperature of 4.5 K. To study these magnets in various operating modes, a test facility equipped with a monitoring and control system was developed. The system provides control and monitoring of the temperature, the pressure in vessels and pipelines, the value of insulating vacuum, and the level and flow rate of liquid helium and nitrogen, 46 channels in total. All parameters of the test facility are recorded in the test archive and stored in ".xls" tables and ".tdms" files on the operator's console. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. Frequency analysis of tetra layered FGM cylindrical shell with S-S Edge condition.
- Author
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Ghamkhar, Madiha, Safdar, Rabia, Batool, Kiran, Maqbool, Abid, Farid, Ghulam, Iqbal, Muhammad Zafar, Abd-Elmonem, Assmaa, and Suoliman, Nagat A. A.
- Subjects
- *
CYLINDRICAL shells , *PRESSURE vessels , *CURVED surfaces , *HEAT exchangers , *CHARACTERISTIC functions - Abstract
A Cylindrical shell consists of a curved surface that extends around a central axis, with its thickness being relatively small compared to its height and radius. It has wide range applications in pressure vessels and tanks, heat exchangers, aerospace etc. This article analyzes four shell surfaces, the first and third layers of functionally graded material, and the second and fourth layers of isotropic material. The natural frequency is influenced by several thick layers. The shell frequency equation is obtained by usig the Rayleigh-Ritz approach. The strain and curvature-displacement relations are derived from Sander's shell theory. Characteristic beam functions are employed to assess the dependence of axial modal and trigonometric volume fraction law is used to attain the vibration anaylsis. Results are acquired for different thickness-to-radius and length-to-radius ratios under various edge conditions. For simply supported edge circumstances, the natural frequencies are calculated by using MATLAB software. [ABSTRACT FROM AUTHOR]
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- 2024
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29. Eel and grouper optimizer: a nature-inspired optimization algorithm.
- Author
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Mohammadzadeh, Ali and Mirjalili, Seyedali
- Subjects
- *
METAHEURISTIC algorithms , *OPTIMIZATION algorithms , *PRESSURE vessels , *GROUPERS , *MARINE ecology - Abstract
This paper proposes a meta-heuristic called Eel and Grouper Optimizer (EGO). The EGO algorithm is inspired by the symbiotic interaction and foraging strategy of eels and groupers in marine ecosystems. The algorithm's efficacy is demonstrated through rigorous evaluation using nineteen benchmark functions, showcasing its superior performance compared to established meta-heuristic algorithms. The findings and results on the benchmark functions demonstrate that the EGO algorithm outperforms well-known meta-heuristics. This work also considers solving a wide range of real-world practical engineering case studies including tension/compression spring, pressure vessel, piston lever, and car side impact, and the CEC 2020 Real-World Benchmark using EGO to illustrate the practicality of the proposed algorithm when dealing with the challenges of real search spaces with unknown global optima. The results show that the proposed EGO algorithm is a reliable soft computing technique for real-world optimization problems and can efficiently outperform the existing algorithms in the literature. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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30. Investigation on the oxidation aging resistance of asphalt by rejuvenator-loaded porous CaCO3 microparticles.
- Author
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Huang, Wenke, Yang, Haolong, Yang, E., Deng, Weilin, Wu, Haiyong, Wu, Kuanghuai, and Yang, Guoliang
- Subjects
- *
ASPHALT pavements , *TRANSMISSION electron microscopy , *PRESSURE vessels , *BINDING energy , *SCANNING electron microscopy - Abstract
To delay asphalt binder oxidation-aging, a slow-release strategy was proposed, wherein porous CaCO3 microparticles act as a sustained-release carrier. Porous CaCO3 microparticles act as rejuvenators to supplement the evaporated saturate and aromatic fractions during the asphalt pavements service life. Porous CaCO3 microparticles were designed and synthesised via a double-decomposition method, and a vacuum-assisted method was applied to load the rejuvenator into the nanopores. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and laser particle size analysis indicated the successful synthesis of porous CaCO3 microparticles and the realisation of loading for the rejuvenator. Furthermore, CaCO3 microparticles were added as alternatives to mineral fillers in the neat asphalt binder, and short – and long-term aging was conducted on the asphalt mastic. The aging resistance performance results suggested that the CaCO3 microparticles loaded with the rejuvenator exhibited good slow-release behaviour after 20 and 40 h of pressure vessel aging when the dose of the microparticles reached 30%–50%. In addition, the rejuvenator release mechanism investigated by molecular dynamics (MD) simulations demonstrated that the rejuvenator's diffusion coefficient in the aging asphalt system reached 32.9 × 10−7 cm2/s, an increase of about 24% compared to that of the unaged asphalt system and the binding energy of the asphalt rejuvenator after aging was 7.1 times the binding energy of the nanopore rejuvenator. This study indicates that rejuvenator-loaded porous CaCO3 microparticles are promising sustainable candidates for delaying oxidative aging in the asphalt pavement industry. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Comparative analysis of non-standardised aging methods for asphalt binder against standard laboratory aging and natural field aging.
- Author
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Ezzat, Helal, Awed, Ahmed, Zeiada, Waleed, Gabr, Alaa, Abo-Hashema, Mostafa, and El-Badawy, Sherif
- Subjects
- *
PRESSURE vessels , *ASPHALT pavement recycling , *MATERIAL fatigue , *VISCOSIMETERS , *THIN films - Abstract
This research investigates non-standardised and natural field aging methods, in comparison with standardised ones. Aging in the Rotational Viscometer (RV) for 24 hours was studied. Pressure Aging Vessel (PAV) aging time and film thickness were changed and compared with standard rolling thin film oven (RTFO) and field-aged binders. Finally, a conventional binder preserved from external conditions was tested over 24 months. Results showed that PAV-aged binders may exhibit greater susceptibility to changes captured by RV. The study also noted a higher increase in viscosities at lower shear rates over time in the RV. However, rheological results did not align with RV findings across all binders. Altering asphalt film thickness in the PAV from 32.5 mm to 25 ± 1 mm has a comparable effect to standard RTFO when the original binder is aged directly in the PAV for the same period of time. The recovered asphalt binder from a 15-year-old pavement showed similarities to 25–30 hours for high-temperature measures, and 55 hours for fatigue parameters indicating inconsistency between laboratory and filed aging. Finally, chemical changes indicated by carbonyl index showed that after 24 months of controlled environmental conditions, a conventional binder exhibited only 44% increase in the index compared to RTFO. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Study on the change rule of low-temperature properties of asphalt binder with aging time.
- Author
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Guo, Meng, Guan, Mingyang, Tan, Yiqiu, and Du, Xiuli
- Subjects
- *
ASPHALT pavements , *CRITICAL temperature , *PRESSURE vessels , *AGING prevention , *THIN films , *ASPHALT - Abstract
Low-temperature cracking is common distress in asphalt pavements. Understanding the change rule of its low-temperature properties is helpful in investigating the optimal maintenance timing of asphalt pavement. In this paper, the change rule of low-temperature properties of asphalt binders with aging time is investigated by various indexes. Four asphalt binders and four anti-aging modified asphalt binders were subjected to the rolling thin film oven (RTFO) test and pressure aging vessel (PAV) test. Dynamic Shear Rheometer (DSR) with the 4 mm parallel plates was used to determine the low-temperature properties of asphalt binders. The results show that aging and low temperature have a negative impact on the low-temperature properties of asphalt binders. The anti-aging agent improves the low-temperature properties and aging resistance of asphalt binders. Compared with other indexes, the critical cracking temperature Tc and the critical temperature difference ΔTc are more suitable for analysing the effect of aging on the low-temperature properties of asphalt binders. Also, the ΔTc shows the three-stage decreasing rule of 'fast-slow-fast', with the inflection points. It meant that the low-temperature properties of asphalt binders had been altered at the inflection points, which provided a favourable reference to research on the optimal maintenance timing of asphalt pavement. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. The Impact of Anchoring on Seafloor Integrity: An Integrated Assessment within a Major Bunkering Area of the Maltese Islands.
- Author
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Mizzi, Michelle, Deidun, Alan, Gauci, Adam, and Gauci, Ritienne
- Subjects
- *
MARINE parks & reserves , *AUTOMATIC identification , *PRESSURE vessels , *ANTENNAS (Electronics) , *BUILDING site planning - Abstract
International shipping is a fundamental component of the global economy. As the industry expands, the demand for high-capacity vessels increases, raising concerns about their impact on the marine environment. While awaiting access to port facilities, vessels often anchor to save fuel and prevent drifting, but this practice is a significant cause of mechanical disturbance to the seafloor and benthic habitats. Identifying and quantifying anchoring pressure is essential for better managing and mitigating the damage to the seafloor. The Automatic Identification System (AIS) can be utilized to assess anchoring pressure by transmitting vessel information (e.g., position, type and size) to other vessels and coastal stations. This research evaluates anchoring pressure in a strategically located bunkering area around the Maltese Islands using AIS data collected from an antenna at the University of Malta. An arbitrary index was developed to determine anchoring pressure, and the AIS data was used to create GIS maps showing the location and size of vessels within the bunkering area, as well as plots depicting anchoring pressure by vessel type, seasonality, and density. This study serves as a blueprint for future assessments of anchoring pressures from various maritime activities in other areas around the Maltese Islands and provides a decision support tool for national policy-making related to Descriptor 6 (Seafloor Integrity) of the Marine Strategy Framework Directive (MSFD), the Maritime Spatial Planning Directive (MSPD), and the management plan for Sites of Community Interest (SCI) and Marine Protected Areas (MPAs). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Ferritic–Martensitic Steels in Power Industry: Microstructure, Degradation Mechanism, and Strengthening Methods.
- Author
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Jiang, Hanyang, Huang, Xin, Feng, Yihui, Xiong, Wei, Jin, Zhenyu, and Peng, Guangjian
- Subjects
- *
HIGH temperatures , *PRESSURE vessels , *THERMOMECHANICAL treatment , *DISPERSION strengthening , *SOLID solutions - Abstract
Ferritic–martensitic (F–M) steels are widely used for high‐temperature pressure vessels and reactor cladding structures in power plants. The high operating temperatures and pressures, as well as the radiation environment, significantly challenge the mechanical stability of these steels. Here, the degradation mechanisms in F–M steels during creep and thermal aging under these harsh environments are reviewed. The exceptional mechanical properties of F–M steels are mainly attributed to their well‐constructed microstructures and chemical compositions. Microstructural barriers such as dislocations, solid solution atoms, and precipitates play key roles in resisting degradation. During the long‐term service, the microstructures undergo gradual evolution, resulting in a deterioration of mechanical properties at the macrolevel. In addition to the degradation mechanisms, some recent advancements in strengthening methods, including microalloying strengthening, thermomechanical treatment (TMT), and oxide dispersion strengthening, are summarized, aimed at the development of next‐generation F–M steels. The strengthening of the F–M steels is mainly achieved by enhancing the thermal stability of their microstructures. Insight into both the deterioration mechanisms and strengthening methods of F–M steels may pave the way for new approaches in developing high‐performance steels for applications in next‐generation power plants operating at ultrahigh operating temperatures and pressures. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Jailed high-pressure balloon technique is superior to jailed wire technique in protecting side branch of coronary bifurcation lesions.
- Author
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Qiu, Jiuchun, Li, Longyan, Wang, Weiding, Li, Xinjian, Zhang, Zizhao, Shao, Shuai, Tse, Gary, Li, Guangping, and Liu, Tong
- Subjects
- *
CORONARY disease , *PERCUTANEOUS coronary intervention , *PRESSURE vessels , *TREATMENT effectiveness , *STENOSIS - Abstract
Objectives. This study investigated the influence of higher pressure protection with a small diameter balloon of side branch (SB) on bifurcation lesions. Background. Of the different coronary stent implantation techniques, the modified jailed balloon technique has become a viable option for bifurcation lesions. However, there was no detailed study on the relationship between the balloon inflation pressure of the main vessel (MV) and SB. Methods. In this study, we collected information of patients who underwent percutaneous coronary intervention (PCI) for bifurcated lesions between March 2019 and December 2022. They were divided into two groups according to the operation way: active jailed balloon technique (A-JBT) group and jailed wire technique (JWT) group. Results. A total of 216 patients were enrolled. The A-JBT group had a larger SB stenosis diameter (1.53 ± 0.69 vs. 0.95 ± 0.52, p <.001), the lower degree of stenosis (44.34 ± 18.30 vs. 63.69 ± 17.34, p <.001) compared to the JWT group. However, the JWT group had a higher incidence of SB occlusion (18.0% vs. 1.9%, p <.001) compared to the A-JBT group. Nevertheless, the success rate for both groups was 100%. Conclusions. This novel high inflation pressure and small diameter balloon approach we propose has significant advantages. There is a lower rate of SB occlusion and SB dissection, which is more cost-effective and provides better clinical outcomes for the patient. This method should be considered in the future for treating bifurcation lesions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Contributon-Informed Approach to RPV Irradiation Study Using Hybrid Shielding Methodology.
- Author
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Matijević, Mario, Trontl, Krešimir, and Pevec, Dubravko
- Subjects
- *
MONTE Carlo method , *NUCLEAR reactor materials , *FAST neutrons , *PRESSURE vessels , *RADIATION shielding , *PRESSURIZED water reactors - Abstract
An important aspect of pressurized water reactor (PWR) lifetime monitoring is supporting radiation shielding analyses which can quantify various in-core and out-core effects induced in reactor materials by varying neutron–gamma fields. A good understanding of such a radiation environment during normal and accidental operating conditions is required by plant regulators to ensure proper shielding of equipment and working personnel. The complex design of a typical PWR is posing a deep penetration shielding problem for which an elaborate simulation model is needed, not only in geometrical aspects but also in efficient computational algorithms for solving particle transport. This paper presents such a hybrid shielding approach of FW-CADIS for characterization of the reactor pressure vessel (RPV) irradiation using SCALE6.2.4 code package. A fairly detailed Monte Carlo model (MC) of typical reactor internals was developed to capture all important streaming paths of fast neutrons which will backscatter the biological shield and thus enhance RPV irradiation through the cavity region. Several spatial differencing and angular segmentation options of the discrete ordinates SN flux solution were compared in connection to a SN mesh size and were inspected by VisIt code. To optimize MC neutron transport toward the upper RPV head, which is a particularly problematic region for particle transport, a deterministic solution of discrete ordinates in forward/adjoint mode was convoluted in a so-called contributon flux, which proved to be useful for subsequent SN mesh refinement and variance reduction (VR) parameters preparation. The pseudo-particle flux of contributons comes from spatial channel theory which can locate spatial regions important for contributing to a shielding response. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Design and Failure Analysis of a Vacuum Pressure Vessel for Aerospace Applications using Finite Element Analysis (FEA).
- Author
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Solangi, Eiman, Badri Albarody, Thar Muhammad, Al-Challabi, Sarah, Khan, Javed Akbar, and Ali, Sajjad
- Subjects
STRAINS & stresses (Mechanics) ,PRESSURE vessels ,STRESS concentration ,FINITE element method ,FAILURE analysis - Abstract
This paper provides detailed insights into the external pressure vessels. External pressure vessels are designed to perform under extreme operating conditions, so the selection of material and geometry along with stress analysis are fundamental for their optimal efficiency. The objective of this research is to provide a case study of the material, design, and stress generated in the pressure vessel to make it suitable for thermal and load-bearing applications in the aerospace industry. An aluminum alloy was chosen as the design material due to its low density and high strength. The modeling geometry of the alloy was constructed using the ASME section-VIII division-I div code. After the performed Finite Element Analysis (FEA), modeling was carried out deploying the ANSYS design modeler to obtain the stress concentration and failure mode of the model. The present study demonstrates the behavior of a structure under applied load and identifies the weak areas of its geometry. Based on the external stress at the center of the structure, the maximum and minimum stresses computed are 0.763 MPa and 0.00803 MPa, respectively. It was also found that the maximum strain is generated at the center of the structure and is equal to 1.0834e6 mm/mm, the maximum deformation is equal to 0.00109 mm and also occurred at the center, while the shells of the model are unable to undergo any deformation. FEA results agree with the analytical results, as the errors for hoop stress and equivalent strain are 4.8% and 1.8%, respectively. Thus, the proposed method can be applied to predict the equivalent stress, equivalent strain, total deformation, and stress intensity, which are required for the structural integrity analysis of pressure vessels. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. A Study on Welding Sensitivity Assessment and Deformation Control of International Maritime Organization Type C Liquefied Natural Gas Fuel Tank Support Structures Using the Direct Inherent Strain Method.
- Author
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Park, Dong-Hee, Yang, Jin-Hyuk, Kim, Sung-Hoon, Kim, Jeong-Hyeon, and Lee, Jae-Myung
- Subjects
GAS as fuel ,SHIP propulsion ,PRESSURE vessels ,ALTERNATIVE fuels ,FUEL tanks ,LIQUEFIED natural gas - Abstract
The increasing burden on shipowners and shipping companies due to environmental regulations imposed by the International Maritime Organization (IMO) has led to the adoption of various compliance strategies, including the use of low-sulfur fuel, installation of scrubbers, and the use of liquefied natural gas (LNG) as an alternative fuel. LNG is particularly prevalent in dual-fuel propulsion ships, with the IMO Type C tank being the most commonly used storage facility. The structure of the IMO Type C tank comprises a pressure vessel and supporting saddles, which can be integrated or separate systems. Despite being manufactured within specified tolerances, welding-induced deformation of the tank and saddle is inevitable since the saddle is welded directly onto the hull. In integrated tank–saddle systems, this deformation can lead to cracks in the epoxy resin, which has lower strength and stiffness, as well as burn damage to the resin and wooden blocks from welding heat. In separate tank–saddle systems, installation difficulties can arise due to interference between the fuel tank system and adjacent structures, such as insulation or the fuel preparation room (FPR), resulting from saddle deformation caused by welding. This study analyzes the sensitivity of all weld lines involved in saddle installation using the direct inherent strain (DIS) method. Based on this analysis, the initial welding deformations are evaluated in relation to the welding direction and sequence. Finally, an optimized method for saddle installation is proposed to minimize deformation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. Angiogenesis Dynamics: A Computational Model of Intravascular Flow Within a Structural Adaptive Vascular Network.
- Author
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Nivlouei, Sahar Jafari, Guerra, Ana, Belinha, Jorge, Mangir, Naside, MacNeil, Sheila, Salgado, Christiane, Monteiro, Fernando Jorge, and Natal Jorge, Renato
- Subjects
CHORIOALLANTOIS ,BRANCHING processes ,SHEARING force ,PRESSURE vessels ,WOUND healing - Abstract
Background: Understanding vascular development and the key factors involved in regulating angiogenesis—the growth of new blood vessels from pre-existing vasculature—is crucial for developing therapeutic approaches to promote wound healing. Computational techniques offer valuable insights into improving angiogenic strategies, leading to enhanced tissue regeneration and improved outcomes for chronic wound healing. While chorioallantoic membrane (CAM) models are widely used for examining fundamental mechanisms in vascular development, they lack quantification of essential parameters such as blood flow rate, intravascular pressure, and changes in vessel diameter. Methods: To address this limitation, the current study develops a novel two-dimensional mathematical model of angiogenesis, integrating discrete and continuous modelling approaches to capture intricate cellular interactions and provide detailed information about the capillary network's structure. The proposed hybrid meshless-based model simulates sprouting angiogenesis using the in vivo CAM system. Results: The model successfully predicts the branching process with a total capillary volume fraction deviation of less than 15% compared to experimental data. Additionally, it implements blood flow through the capillary network and calculates the distribution of intravascular pressure and vessel wall shear stress. An adaptive network is introduced to consider capillary responses to hemodynamic and metabolic stimuli, reporting structural diameter changes across the generated vasculature network. The model demonstrates its robustness by verifying numerical outcomes, revealing statistically significant differences with deviations in key parameters, including diameter, wall shear stress (p < 0.05), circumferential wall stress, and metabolic stimuli (p < 0.01). Conclusion: With its strong predictive capability in simulating intravascular flow and its ability to provide both quantitative and qualitative assessments, this research enhances our understanding of angiogenesis by introducing a biologically relevant network that addresses the functional demands of the tissue. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. End-to-End Simulation of Linerless Composite Pressure Vessels Using 3D Continuum Damage Models.
- Author
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Gonçalves, Paulo Teixeira, Arteiro, Albertino, and Rocha, Nuno
- Subjects
PRESSURE vessels ,DAMAGE models ,THERMAL stresses ,TRANSVERSE strength (Structural engineering) ,FINITE element method - Abstract
Linerless composite pressure vessels, or type V pressure vessels, are gaining increased interest in the transportation industry because they offer improved storage volume and dry weight, especially for low-pressure cryogenic storage. Nevertheless, the design and manufacturing of this type of pressure vessel bring several challenges due to the inherent difficulties in the manufacturing process implementation, assembly, and related analysis of structural integrity due to the severe operating conditions at cryogenic temperatures that should be taken into consideration. In this work, a novel analysis procedure using a finite element model is developed to perform an end-to-end simulation of a linerless pressure vessel, including the relevant features associated with automated fiber placement manufacturing processes regarding thickness and tape profiles, followed by an analysis of the structural response under service conditions. The results show that residual stresses from manufacturing achieve values near 50% of the composite ply transverse strength, which reduces the effective ply transverse load carrying capacity for pressure loading. Transverse damage is triggered and propagated across the vessel thickness before fiber breakage, indicating potential failure by leakage, which was confirmed by hydrostatic tests in the physical prototype at 26 bar. The cryogenic condition analysis revealed that the thermal stresses trigger transverse damage before pressure loading, reducing the estimated leak pressure by 40%. These results highlight the importance of considering the residual stresses that arise from the manufacturing process and the thermal stresses generated during cooling to cryogenic conditions, demonstrating the relevance of the presented methodology for designing linerless cryogenic composite pressure vessels. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. The reactor pressure vessel surveillance program of the Belgian nuclear power plants.
- Author
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Wagemans, Jan and Slosse, Nicolas
- Subjects
- *
NUCLEAR power plants , *NUCLEAR reactors , *PRESSURE vessels , *RADIATION dosimetry , *NEUTRON flux - Abstract
This paper presents an overview of the Reactor Pressure Vessel surveillance program as it is applied to the seven Belgian Pressurised Water Reactors (PWR). The first part of the paper recalls the original objectives of the surveillance program, detailing the number of capsules that were installed per reactor, the number that have been retrieved so far and discusses the type of dosimeters installed. The second part is a description of the experimental techniques applied to determine the neutron fluences, a work which is performed in the reactor dosimetry laboratory at SCK CEN and is based on qualified activity measurements. Finally, the paper ends by briefly presenting the calculation scheme developed at Tractebel and by providing a statistical analysis of the C/E values over the ~ 400 in-core dosimeters and 800 ex-core dosimeters that have been analysed to date. The method offers satisfactory results with an average C/E on all dosimeters close to 1.0 and a standard deviation comprised between 8 % and 10 % depending on the dosimeter considered. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Investigation of RPV samples of the Greifswald NPP with focus on retrospective dosimetry.
- Author
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Poenitz, Erik and Konheiser, Joerg
- Subjects
- *
NUCLEAR reactors , *PRESSURE vessels , *RADIATION dosimetry , *RADIOISOTOPES , *METAL cladding - Abstract
Reactor pressure vessel (RPV) samples of units 1 and 4 of the Greifswald NPP were investigated with focus on retrospective dosimetry. Specific activities of long-lived radionuclides 63Ni, 93mNb, 94Nb and 99Tc as well as the concentrations of the producing elements were measured. Investigated samples comprise base metal, welding metal and cladding of the RPV. Neutron fluences obtained with the M onte-Carlo codes TRAM O and M CNP were used to calculate specific activities. The gamma-emitter 94Nb appears as a promising candidate due to the large Nb concentration in the cladding of the VVER RPVs. For 93mNb, a very good agreement of measured und calculated activities was found for the RPV cladding samples where 93mNb is primarily produced by the threshold reaction 93Nb(n,n')93mNb. A strong scatter of the ratios of calculated and experimental activities is observed for 63Ni which is primarily produced by slow neutrons. For 99Tc, a good agreement of calculated and measured activities was found for the majority of the base metal and welding metal samples but not for the cladding samples. Updated reaction cross section data for 62Ni(n,γ) and 92M o(n,γ) lead to a better agreement of calculated and measured activities for 63Ni and 93mNb. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. A quantified approach to assessing the effectiveness of nuclear reactor pressure vessel neutron fluence monitoring programs.
- Author
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Kulesza, Joel and Fischer, Greg
- Subjects
- *
NUCLEAR reactors , *PRESSURE vessels , *NEUTRON flux , *RADIATION dosimetry , *NUCLEAR engineering - Abstract
This paper presents a quantitative approach to characterize the effectiveness of neutron fluence monitoring programs using adjoint neutron transport calculations. The results of adjoint calculations are useful for this purpose because the adjoint solution is the expected contribution from one region of phase space to a response of interest, i.e., the importance of that region of phase space to the response. Thus, by identifying a response of interest (for this work, the fast (E > 1.0 MeV) neutron fluence rate at the peak fluence rate location in the reactor pressure vessel (RPV)), one can identify the fuel regions most important to that response. Once identified, the ability of various surveillance programs to adequately monitor the most-important fuel region(s) can be assessed. The approach described is applied to a three-loop Westinghouse pressurized water reactor to compare the effectiveness of surveillance-capsule neutron dosimetry versus ex-vessel neutron dosimetry to monitor the fuel assemblies that contribute to the peak fast (E > 1.0 MeV) neutron fluence rate in the RPV. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Improved determination of fast neutron fluence onto the WWER pressure vessel metal surveillance specimens.
- Author
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Pugach, O.M., Bukanov, V.M., Diemokhin, V.L., Grytsenko, O.V., and Vasylieva, O.G.
- Subjects
- *
FAST neutrons , *NUCLEAR reactors , *PRESSURE vessels , *RADIATION dosimetry , *NUCLEAR engineering - Abstract
The special methodology for the determination of the neutron fluences onto the surveillance specimens of the WWER-1000 reactor pressure vessel metal has developed by INR NASU specialists and is successfully applied. The methodology is based on the Monte-Carlo code that is used for neutron transport calculations to the locations of the surveillance specimens. The methodology improvement is described. The fundamentals of the technique of the calculation-experimental determination of the fast neutron fluences onto surveillance specimens and their errors are presented. It is shown a dosimetry experiment in a particular reactor is needed to obtain experimental data about irradiation conditions in the locations of the surveillance specimens. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Further development, validation and verification of the Monte-Carlo code TRAMO on ex-vessel experiments of the Greifswald NPP.
- Author
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Baier, Silvio, Konheiser, Jörg, and Pönitz, Erik
- Subjects
- *
NUCLEAR power plants , *NUCLEAR engineering , *AUTOMATION , *NUCLEAR reactors , *PRESSURE vessels - Abstract
TRAMO is a Monte Carlo code which is specially designed for geometries of nuclear power plants. In recent years, TRAMO has undergone a number of technical developments. In addition to the conversion to modern Fortran, standardized models for VVER-440 and VVER-1000 for the evaluation of monitor experiments on the surface of the reactor pressure vessel were developed, and the corresponding pre- and post-processing was automated. The new TRAMO version is continuously validated and verified. Here we present comparisons with experimental data from unit 1 of the Greifswald nuclear power plant and with MCNP calculations. Earlier calculations with TRAMO showed good agreements in the middle region of the reactor core, but significant deviations outside. A possible explanation is the wrong documentation of the experimental data – especially the heights of the monitors. Assuming a downward shift of the monitor positions by about 24cm, experimental and calculated data show very good agreement. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Real-time optical holographic interferometry for high-speed high-sensitivity deformation studies.
- Author
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Tringe, Joseph W., Pease, Steven, Ovenell, Ryan T., Baldwin, Molly G., Vuppuluri, Vasant S., and Keene, Lionel T.
- Subjects
- *
DIGITAL image correlation , *STRAIN gages , *IMPACT (Mechanics) , *PRESSURE vessels , *HOLOGRAPHIC interferometry , *BANDWIDTHS - Abstract
Time-resolved strain and deformation measurements are valuable as indirect indicators of internal pressure for confinement vessels, and as direct measures of early-time response in mechanical impact experiments. Surface-mounted strain gages are the most common methods of strain determination, offering high-sensitivity and high temporal resolution due to the low bandwidth requirements involved in sampling a simple electrical signal. However, as point measurements they can only represent a small fraction of the area of interest. Digital Image Correlation (DIC) is a common alternative offering full-field deformation/strain determination, but suffers from an inverse relationship between field-of-view and sensitivity. In contrast to these methods, traditional holographic interferometry offers wavelength-level sensitivity that is independent of object size or field-of-view and can operate at high temporal resolution using modern high-speed cameras. In this work we show how modern photopolymeric materials simplify the application of in situ holographic interferometry materials to enable holographic interferometry in deflagration-to-detonation studies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Rheology and Aging Resistance of Asphalt Modified with Calcined Kaolin.
- Author
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Hu, Chunhua, Tian, Wen, Zhu, Ruipeng, and Zhang, Hao
- Subjects
- *
ASPHALT modifiers , *STRAINS & stresses (Mechanics) , *ELASTICITY , *MATERIAL fatigue , *PRESSURE vessels , *ASPHALT - Abstract
This study aimed to explore the potential of calcined kaolin (CK) as an asphalt modifier. CK at 5%, 10%, 15%, and 20% by asphalt weight was blended in asphalt binder at a high temperature, followed by aging treatments using a rolling thin film oven (RTFOT) and a pressure aging vessel (PAV). Changes in rutting, fatigue, temperature susceptibility, and aging resistance of the modified asphalt were tracked. The composition and structure of CK were analyzed using X-ray diffraction (XRD) and backscattered electron imaging-particle size (BSD-PS). Rheological studies of the modified asphalt were conducted using rotational viscosity, frequency sweep, multiple stress creep recovery (MSCR), and linear amplitude sweep (LAS) tests. The effects of CK on bitumen after thermo-oxidative aging performance decay were evaluated using aging indexes of physical indicators, complex modulus, and the phase angle. With the addition of CK, significant enhancement to stiffness was observed in the low- to mid-frequency range in the asphalt master curves, indicating that the impact of CK was mainly within the medium- to high-temperature range. The MSCR test results showed that the Jnr3.2 value for CK-modified asphalt accounts for 62% to 71% of virgin asphalt, indicating high rutting performance. The Cole–Cole diagram revealed different degrees of slope deviation toward the storage modulus axis for the storage and loss modulus curves after adding CK, suggesting an improvement in the asphalt's elastic properties. The CK asphalt binder exhibited higher R -values (152% to 181% of the virgin asphalt for R0.1 in the MSCR test) and fatigue cycle times (118% to 155% of the virgin asphalt for Nf in the LAS test) than those of virgin asphalt. Aging indexes and the Fourier-transform infrared spectroscopy (FTIR) test results indicated that CK can delay oxygen diffusion and the volatilization of lighter components. In conclusion, the results demonstrate that CK can effectively serve as a modifier to improve the mechanical and aging properties of asphalt binders. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
48. Study of Aging Asphalt Recovery Using Peanut Oil Residue as a Biomass Regenerator.
- Author
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Xu, Shanshan, Sun, Daheng, and Zhang, Xinxin
- Subjects
- *
FATIGUE limit , *PEANUT oil , *RHEOLOGY , *PRESSURE vessels , *MATERIAL fatigue , *ASPHALT - Abstract
The properties of reclaimed asphalt were studied using peanut oil residue (POR) as a regenerant. The preparation, chemical composition, and rheological properties of POR regenerant were studied. GC-MS and FITR studies of the chemical composition of reclaimed asphalt found that there was a large amount of light oil in POR. After the addition of bio-oil, the functional group index of the aged asphalt showed a downward trend, indicating that it can effectively adjust the asphalt components. The rheological properties of 90# asphalt after pressure aging vessel (PAV) aging were tested by adding 3%, 6%, 9%, 12%, and 15% POR regenerator. In the aspect of low-temperature performance, with the increase in bio-oil content the m -value continued to increase and the S value continued to decrease. When the content of POR was in the range of 3%–6%, the performance index of the asphalt after aging and regeneration reached the level of the matrix asphalt. When the temperature dropped to −22°C , the low-temperature performance index of the asphalt decreased as the content of POR regenerant was slightly increased. In terms of high-temperature performance, the use of POR as a regenerant can alleviate the declining trend in the fatigue durability curve of the complex modulus of recycled asphalt, in which 9% POR can effectively restore fatigue resistance. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
49. Influence of Submerged Arc Welding Parameters on 304L/H Steels Undergoing Shallow Heat Treatment.
- Author
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Özdemir, Zafer
- Abstract
Submerged arc welding (SAW) is extensively employed in the pressure vessel industry because of its high quality and automation capabilities. To achieve high melting efficiency and superior mechanical properties based on welding parameters, optimization is vital. In this study, the effects of SAW parameters on the physical and mechanical properties of ASTM-A-240 (304L stainless steel) and ASTM-A-240 (304H stainless steel) via different kind of heat treatment processes were examined. Half of the samples (3 samples for each parameter, total 18) underwent to conventional heat treatment (annealing, quenching and tempering), and the other half (3 samples for each parameter, total 18) were subjected to shallow heat treatment (SHT) at − 80 °C and were compared in terms of hardness and toughness. Welding was conducted at three different currents (600 A, 700 A and 800 A) and travel speeds (5, 11 and 14 mm/s) on sample plates measuring 900 mm × 110 mm × 15 mm. The weld quality and properties were evaluated through weld geometry measurements, visual inspection, hardness testing and Charpy impact testing. Charpy specimens/samples were prepared according to ASTM E-23. Welding utilized a direct current electrode positive (DCEP) setup with a constant current. The results show that welding current and speed significantly influence impact energy, especially in the weld metal (WM), although hardness values did not vary significantly. Charpy impact tests indicated that the parent metal (PM) of both steels exhibited the lowest toughness, whereas the WM displayed the highest toughness for a given weld. The heat-affected zone (HAZ) showed intermediate toughness. Higher travel speed positively impacts HAZ and WM toughness. Increasing welding speed and current enhance toughness. It has also been observed that the shallow heat treatment affects the toughness and hardness positively. After SHT, it has been observed that impact toughness is increased approximately 4% and hardness is increased approximately 3% compared to conventional heat treatment. [ABSTRACT FROM AUTHOR]
- Published
- 2025
- Full Text
- View/download PDF
50. Multi-objective process parameters optimization of laser repairing steel plate in pressure vessels using machine learning.
- Author
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Fan, Kaijun, Shi, Yongjun, Zhuang, Chao, Wang, Shuyao, Wang, Qin, Tian, Mingjun, Li, Ying, Yan, Xinyu, Liu, Yangshu, and Xu, Feihong
- Subjects
- *
PRESSURE vessels , *MACHINE learning , *PREDICTION models , *LASERS , *ALGORITHMS - Abstract
AbstractLaser cladding (LC) is an additive manufacturing technology, and it is often used to repair damaged parts. This study uses machine learning to optimize the process parameters for LC repair of Q345R pressure plates. The BP neural network improved by the SSA algorithm (SSA-BP) was trained using data obtained from experiments. Then the process parameters were optimized by NSGA-II. Compared with other process parameters, the sample prepared with optimal process parameters has a higher impact absorption energy, reflecting the effectiveness of the optimization. This study provides guidance for the optimization of multi-objective process parameters in laser cladding repairing. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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