bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling of Residual Stresses in Multi-Pass Pipe Circumferential Butt Welds Made of Austenitic Stainless Steel to Provide Indicators for SCC Risk Classification
Authors: Robin V. , Hendili S. , Delmas J. , Hilal S. , Iampietro D. , Abbas M. , Jutteau S. 
Published: November 2023

Abstract
Prediction of residual stresses in welds is essential in order to evaluate the integrity of a component subject to degradation mechanisms such as Stress Corrosion Cracking. During welding operations, complex thermo-mechanical and metallurgical processes take place and lead to microstructural changes such as dynamic recovery and dynamic recrystallization. These microstructural changes induce a modification of hardening behavior that should be taken into account to accurately evaluate residual stresses through numerical simulations. In the as-welded conditions, multi-pass pipe circumferential butt welds made of austenitic stainless steel show a typical residual stress profile through the wall of the welded joint. Such a shell bending profile places the inner half of the weld joint wall and its vicinity in compression in the axial direction. However, tensile zones can appear in the inner wall near the axis of the weld.
A large simulation campaign was carried out in order to cover different welding configurations and confirm these trends. This digital chart is built on the basis of a design of experiments of 100 Numerical Simulations of Welding per diameter and schedule. The parameters are:
- Diameter, thickness,
- Welding processes (GTAW, SMAW...),
- Groove shape.
This set of simulations show the systematic presence of a compression zone on the inner side, with some variability depending on the welding conditions and geometry. The classification of SCC risk is then defined by a set of two indicators that can be related to crack initiation (stress, strain hardening near the surface) and propagation (stress, strain hardening in the bulk). Considering in service loads in addition to realistic Weld Residual Stresses (WRS) makes Stress Intensity Factor (SIF) analysis feasible considering idealized crack position and orientation.
Elimination of the 48-Hour Hold for Ambient Temperature Temper Bead Welding With Austenitic Weld Metal
Authors: McCracken Steven L. , Patel Asif 
Published: November 2023

Abstract
Temper bead welding rules in the ASME Section XI code and code cases have historically required a 48-hour hold (wait period) after the temper bead weldment has cooled to ambient temperature prior to performing the final nondestructive examination (NDE). The purpose of the 48-hour wait period is to ensure that if delayed hydrogen induced cracking (HIC) occurs it is detected by the final acceptance examination. Delayed HIC is known to occur up to 48 hours after the weldment cools to ambient temperature when appropriate welding techniques and low hydrogen practices are not applied. A recent revision to Case N-888, the ambient temperature temper bead case for SMAW and Machine GTAW, eliminates the 48-hour hold for temper bead welds on P-No. 1 and P-No. 3 base material when austenitic weld metal is used. This paper summarizes the technical basis for this change and references operating experience that demonstrates the 48-hour hold is inconsequential and there is no potential for HIC when temper bead welding is deployed with low hydrogen practices and austenitic weld metal.
Effect of Temperature and Seawater Exposure on Glass/Polyurethane Composite: Experimental and Failure Analysis
Authors: Idrisi Amir Hussain , Ismail Mourad Abdel-Hamid 
Published: November 2023

Abstract
The lack of durability is the major issue faced by polymers and their composites for saline water exposure. The experimental investigation of seawater exposure of Fiber reinforced polymer (FRP) composite is limited to a short period of time. Also, this small range of data was used in the development of the prediction model. The present paper reports a long-term experimental investigation and prediction of the durability of FRP composites exposed to seawater at different temperatures. E-glass/polyurethane samples were exposed to 23 °C, 45 °C and 65 °C seawater for up to 2700 days (90 months). Tensile tests evaluated the mechanical performance of the composite as a function of exposure time, and a strength-based technique was used to assess the durability. The experimental results revealed that the tensile strength of the composite reduced by 37.6% and 63.6% after immersion of 90 months in seawater at 23 and 65 °C, respectively. The prolonged immersion in seawater results in plasticization and swelling in the composite material, which accelerates the fiber/matrix debonding. Failure analysis was performed to investigate the failure mode of the samples. SEM micrographs indicate fiber/matrix debonding, potholing, fiber pull-out, river line marks, and matrix cracking which indicates deterioration in the tensile properties of the composites.
Fatigue Analysis of a Pressure Swing Adsorption Vessel
Authors: Kumar Raman Senthil 
Published: November 2023

Abstract
Pressure Swing Adsorption technology is used to separate any gas from a mixture of gases under pressure according to the gas molecular characteristics and its affinity for an adsorbent material. The process operates at near-ambient temperatures and specific adsorptive materials (e.g., activated carbon, molecular sieves, etc.) are used to preferentially adsorb the target gas at high pressure. The process then swings to low pressure to desorb the adsorbed material.
Adsorption and desorption normally take place alternately at equal time intervals which sets the pressure cycle in a pressure vessel. The cycles are usually produced by internal pressure or vacuum caused by the swing operation. This paper focuses on an investigation to determine the design fatigue life of an adsorption vessel subjected to over 10 million cycles of design internal pressure and vacuum. The paper also highlights the effect of reaching full vacuum conditions on the fatigue life of the vessel during the pressure cycle.
The fatigue evaluation is performed considering the normal operation of the equipment during the entire life cycle of the plant. The adsorber vessel under investigation replaces an existing vessel due to the improved process performance requirements of the plant and hence provided with four leg supports welded directly to the vessel head to avoid modifications to existing base supports in the plant. A 3D model of the full vessel is considered, meshed and the fatigue evaluation is done as per ASME Sec VIII Div. 2, Part 5, Annexure 3-F.1. FEA software ANSYS® is used to perform the stress analysis. Vessel fatigue life is estimated according to the alternating stresses at the highest stress point i.e., at the leg to head junction.
Computational Analysis of a Piping Structure Subject to Thermal Striping
Authors: Harper Chris , Crowther Paul , Chauvet Christian 
Published: November 2023

Abstract
Fatigue failure of piping structures due to thermal striping occurs when hot and cold flow streams are mixed at a piping junction. Interaction of the two streams can lead to formation of a shear layer and periodic vortex shedding at the mixing boundary of the hot and cold fluid. The impact of these vortices on the inside pipe wall result in variable thermal loads on the inner pipe wall and localized high cycle thermal stresses. It is a relatively infrequent but potentially catastrophic degradation mechanism in many industries, which see mixing of fluid flows with large temperature differences.
This paper describes the effect of thermal striping induced fatigue failure of piping structures and an approach for analysis using a combination of Computational Fluid Dynamics (CFD) and structural Finite Element Analysis (FEA). The fluid dynamics analysis is first completed in this study where a cold flow stream is mixed with a hot flow stream at a piping T-junction. It predicts the flow and temperature fluctuations in the system and provides the frequency and amplitude of oscillations. The structural mechanics analyses are employed to extract time-dependent strain and stress values of the pipe under thermal loadings. Afterwards, the fatigue life of the pipe is obtained using fatigue failure analysis which is then used to verify the study approach by comparing the results with those of a real incident in an oil and gas plant.
The effect of installing an internal nozzle is investigated and confirmed by the computational approach. Finally, a criterion for when thermal striping may be of concern in a piping layout and should be analyzed further is proposed.
A Study on Reliability of Piping System Supported by Elasto-Plastic Support Subjected to Nonstationary Seismic Waves
Authors: Shintani Atsuhiko , Nakagawa Chihiro , Ito Tomohiro 
Published: November 2023

Abstract
The responses of piping systems subjected to nonstationary seismic waves are investigated. A piping system subjected to non-stationary artificial seismic waves is modeled using L-shaped piping supported by elasto-plastic supports. The nonstationary seismic waves are produced through a stationary stochastic Gaussian noise process weighted by a deterministic function. This deterministic function has similar seismic frequency characteristics as an actual earthquake. The power of an artificial seismic wave is adjusted by equalizing the power of the white Gaussian noise. Next, the reliability of the piping based on its stress, energy absorption ratio from the support, and energy absorption balance are employed as indices. Based on these indices, the response of piping subjected to nonstationary seismic waves is investigated and compared to the response subjected to stationary Gaussian noise. The reliability of the piping system, the energy absorption ratio of the supports, and the energy absorption balance based on the application of white noise and nonstationary waves as inputs are investigated.
Hydrocracker Gasket Lipseal Design and Fabrication Learning
Authors: Perilloux Charles , Huff Mary Catherine , Adams Amy , Rhodes John , Penso Jorge , Stierwald Robert 
Published: November 2023

Abstract
In this paper, reliability underperformance of welded lipseal is analyzed. A fillet weld located between the channel cover and lipseal on a hydrocracker second stage feed/effluent exchanger developed leaks. The reactor effluent fluid comprises hydrogen, naphtha and diesel above 1,900psig. Before the leaks occurred, there were multiple start-up and shutdown cycles. These cycles created sufficient stress to drive cracking though the fillet weld of the seal. During the failure investigation, some deviations in weld location and size were identified. The stress from subsequent thermal cycles was high enough to exceed the weld strength.
The lip height created a difficult angle for the welder to work. This resulted in less metal being applied in some areas and variation in weld placement. The flange and gasket area were too restricted to use a fillet gauge. Liquid penetrant inspection and hydrotest were not robust enough barriers to prevent the leaks.
Finite element-based fatigue analyses following industry standard API 579-1/ASME FFS-1 was performed. It found that a minimum weld size above what was found in the failure inspection was required to sustain observed fatigue cycles. The finite element model was calibrated using results of an infrared inspection.
Recommendations following investigation include design and fabrication modifications to minimize occurrences of similar events. The importance of considering potential severe cyclic service scenarios in the design is highlighted. Similar seal weld leaks have been reported in the industry.
Life Management of Pressure Swing Absorbers
Authors: Karstensen Annette , Seipp Trevor , Nadarajah Chithranjan 
Published: November 2023

Abstract
Pressure cycles in a hydrogen environment can seriously affect the fatigue life of pressure swing absorbers (PSAs). PSAs are typically designed for a 20 to 30-year life and by the time the intended design life is approaching, many operators are challenged with making decisions as to whether they need to purchase new vessels or explore whether or not life extension is a viable option.
In many cases, towards the end of design life or during midlife (50–60% of design life), operators elect to conduct a life extension study that includes a Level 3 Fitness for Service assessment and Finite Element Analysis (FEA) to evaluate the areas of high stress where fatigue cracks might initiate. The outcome from the FEA is used to develop an inspection strategy. In most cases, it will show that the areas of high stress are around the inlet and outlet nozzles. However, most PSA vessels are well fabricated with nozzles or manways having integral reinforcement and blended nozzle welds, making these areas less susceptible to crack initiation.
In the authors’ experience, the real integrity concern is weld peaking in the long seams and/or weld misalignment, and this will not be highlighted by an FEA made from design drawings. Therefore, this paper examines the effect on weld peaking at the longitudinal seams on the fatigue life. However, other potential crack locations are at internal attachment welds, for example, where the inlet screen is welded to the bottom head and these should in general also be considered when inspection strategies and integrity management plans are developed for PSA vessels.
The work described in this paper highlights how it is possible to operate PSAs beyond design life by developing inspection plan based on a fracture mechanics approach and basing the underlying FEA stress analysis on laser scan data to capture the level of weld peaking in the long seam welds.
Study on Seismic Evaluation for Anchor Bolts in Circular Arrangement Using Elastic-Plastic Analysis
Authors: Terai Kensuke , Amino Masanori , Tamura Ichiro , Iida Satoshi 
Published: November 2023

Abstract
In a seismic evaluation of process equipment, anchor bolts for a component are required to resist against seismic conditions to support the component on the basement. Some components are directly fixed to the basement by anchor bolts, and anchor bolts of many cylindrical tanks or vessels are arranged on the circumference. Anchor bolts are basically designed in elastic base, but actual materials of them are confirmed to show plastic behavior by tensile testing. For rational evaluation for increasing seismic condition, an elastic-plastic analysis method has been studied to take account the condition that a few of the anchor bolts in circular arrangement become beyond elastic limit by seismic load. In this condition, even if yielding of a few bolts is occurred, it is expected that the other bolts within elastic limit bear against the seismic loads and keep equipment support function of the anchor bolts.
To evaluate this condition, static loading tests using a reduced scale model of a cylindrical storage tank and static pushover analyses taking into account the elastic-plastic characteristics of the anchor bolt material were performed.
Theoretical Solution of Obround Shell Under Internal Pressure
Authors: Jin Yao , Rust James 
Published: November 2023

Abstract
Pressurized enclosures with obround cross sections are common components in the petrochemical industries. Since no theoretical solutions are currently available, the analysis and design of such components mainly relies on empirical or numerical analysis methods. In engineering practice, the determination of shell wall thickness requires complex iterations. In this study, obround shapes are regarded as curved and straight segments with corresponding boundary conditions, respectively. The geometry and boundary conditions of each segment are relatively simple. The theoretical analysis of each segment was performed separately. By combining the existing closed-form solutions, a theoretical solution that partially satisfies the coordination of deformation at segment junction is obtained. The proposed combined solution can accurately describe the stress and displacement distributions of an obround shell under internal pressure. Considering the uniqueness of the elastic solution, the proposed solution is the closed-form theoretical solution for pressurized obround shells. When the straight segments of the obround section disappear, the obround becomes a circle. The proposed solution returns to the solution of cylindrical shell or Lame’s solution. The proposed solution can be considered as extended Lame’s solution. The solution provides a new theoretical analysis method. It is simpler, more efficient, and more accurate than empirical methods and numerical analysis. It is expected to change the status quo that the analysis of obround components relies on empirical formulas and numerical analysis, and to develop a new design method for obround components.
Pharmacological validation of dihydrofolate reductase as a drug target in
Mycobacterium abscessus
Authors: Aragaw Wassihun Wedajo , Negatu Dereje A. , Bungard Christopher J. , Dartois Véronique A. , Marrouni Abdellatif El , Nickbarg Elliott B. , Olsen David B. , Warrass Ralf , Dick Thomas 
Published: November 2023

ABSTRACT

The
Mycobacterium abscessus
drug development pipeline is poorly populated, with particularly few validated target-lead couples to initiate
de novo
drug discovery. Trimethoprim, an inhibitor of dihydrofolate reductase (DHFR) used for the treatment of a range of bacterial infections, is not active against
M. abscessus
. Thus, evidence that
M. abscessus
DHFR is vulnerable to pharmacological intervention with a small molecule inhibitor is lacking. Here, we show that the pyrrolo-quinazoline PQD-1, previously identified as a DHFR inhibitor active against
Mycobacterium tuberculosis
, exerts whole cell activity against
M. abscessus
. Enzyme inhibition studies showed that PQD-1, in contrast to trimethoprim, is a potent inhibitor of
M. abscessus
DHFR and over-expression of DHFR causes resistance to PQD-1, providing biochemical and genetic evidence that DHFR is a vulnerable target and mediates PQD-1’s growth inhibitory activity in
M. abscessus
. As observed in
M. tuberculosis
, PQD-1 resistant mutations mapped to the folate pathway enzyme thymidylate synthase (TYMS) ThyA. Like trimethoprim in other bacteria, PQD-1 synergizes with the dihydropteroate synthase (DHPS) inhibitor sulfamethoxazole (SMX), offering an opportunity to exploit the successful dual inhibition of the folate pathway and develop similarly potent combinations against
M. abscessus
. PQD-1 is active against subspecies of
M. abscessus
and a panel of clinical isolates, providing epidemiological validation of the target-lead couple. Leveraging a series of PQD-1 analogs, we have demonstrated a dynamic structure-activity relationship (SAR). Collectively, the results identify
M. abscessus
DHFR as an attractive target and PQD-1 as a chemical starting point for the discovery of novel drugs and drug combinations that target the folate pathway in
M. abscessus
.
Healthy diet intervention reverses the progression of NASH through gut microbiota modulation
Authors: Panyod Suraphan , Wu Wei-Kai , Hu Meng-Yun , Huang Huai-Syuan , Chen Rou-An , Chen Yi-Hsun , Shen Ting-Chin David , Ho Chi-Tang , Liu Chun-Jen , Chuang Hsiao-Li , Huang Chi-Chang , Wu Ming-Shiang , Sheen Lee-Yan 
Published: November 2023

ABSTRACT
Diet and gut microbiota impact the progression of non-alcoholic steatohepatitis (NASH). An unhealthy diet, rich in fat and sugar, promotes gut microbiota dysbiosis, leading to the translocation of lipopolysaccharides (LPS) and other harmful pathogen-associated molecular patterns to the liver, triggering hepatic inflammation and aggravating NASH. Currently, there are no approved pharmacological treatments for NASH, although novel drugs, such as obeticholic acid (OCA), have demonstrated beneficial effects. Healthy dietary modifications have been proposed to prevent and treat NASH. However, the therapeutic effect of the combined implementation of a healthy dietary intervention with pharmaceutical agents or dietary supplements for NASH treatment and how it interplays with the gut microbiota and associated pathways remains poorly understood. This study aims to investigate the therapeutic efficacy of a healthy dietary modification, either alone or in combination with a dietary supplement [ginger essential oil (GEO)] or drug (OCA), in a Gubra-Amylin diet-induced NASH mouse model. NASH was induced for 12 weeks, after which the interventions were administered for a subsequent 3-week period. Our findings revealed that healthy dietary intervention primarily restores obesity, lipidemia, and NASH. In contrast, GEO and OCA have additional benefits by suppressing pro-inflammatory cytokines by partially modulating the NLRP3/ASC/caspase-1 pathways. Moreover, healthy dietary intervention restores gut microbiota composition and function from dysbiosis, while GEO and OCA partially mediate the gut-derived LPS/toll-like receptor 4/nuclear factor kappa B pathway. Therefore, adherence to healthy dietary patterns plays a primary role in NASH reversion, and additional supplementation of GEO or OCA could offer extra benefits in suppressing hepatic inflammation and preventing disease progression.

IMPORTANCE
The link between gut microbiota and diet is crucial in the development of non-alcoholic steatohepatitis (NASH). This study underscores the essential role of a healthy diet in preventing and treating NASH by reversing obesity, lipidemia, and gut microbiota dysbiosis. Moreover, the supplementation of functional food or drug to the diet can provide additional advantages by inhibiting hepatic inflammation through the modulation of the hepatic inflammasome signaling pathway and partially mediating the gut microbiota and lipopolysaccharide signaling pathway. This study highlights the importance of adopting healthy dietary habits in treating NASH and proposes that supplementing with ginger essential oil or obeticholic acid may offer additional benefits. Nonetheless, further clinical studies are necessary to validate these findings.