bluuebunny/crossref_metadata_2025 huggingface dataset:
Dental microwear texture analysis reveals a likely dietary shift within Late Cretaceous ornithopod dinosaurs
Authors: Kubo Tai , Kubo Mugino O. , Sakamoto Manabu , Winkler Daniela E. , Shibata Masateru , Zheng Wenjie , Jin Xingsheng , You Hai‐Lu
Published: December 2023

Dinosaurs were the dominant megaherbivores during the Cretaceous when angiosperms, the flowering plants, emerged and diversified. How herbivorous dinosaurs responded to the increasing diversity of angiosperms is largely unknown due to the lack of methods that can reconstruct diet directly from body fossils. We applied dental microwear texture analysis (DMTA), an approach that quantifies microtopography of diet‐induced wear marks on tooth surfaces, to ornithopods, the dinosaur clade that includes taxa with the most sophisticated masticatory system. We found that Late Cretaceous ornithopods have significantly rougher dental microwear texture (DMT) compared to pre‐Late Cretaceous ornithopods, and DMT variation increased in hadrosaurids, a derived Late Cretaceous ornithopod clade. These changes indicate a likely temporal dietary shift towards more abrasive foodstuffs within ornithopods, probably due to the increased ingestion of phytoliths (amorphous silica bodies in plants). Phytoliths are a main source of rough DMT in modern herbivores, along with exogenous dust and grit, and were generally more concentrated in Late Cretaceous angiosperms than in other major plant groups. Our results show that DMTA of the occlusal enamel surface can be used to reconstruct the diets of herbivorous dinosaurs, with a resolution superior to conventional methods.
Climate gradient and leaf carbon investment influence the effects of climate change on water use efficiency of forests: A meta‐analysis
Authors: Li Shenglan , Agathokleous Evgenios , Li Shuangjiang , Xu Yansen , Xia Jiaxuan , Feng Zhaozhong
Published: November 2023

Forest ecosystems cover a large area of the global land surface and are important carbon sinks. The water‐carbon cycles of forests are prone to climate change, but uncertainties remain regarding the magnitude of water use efficiency (WUE) response to climate change and the underpinning mechanism driving WUE variation. We conducted a meta‐analysis of the effects of elevated CO2 concentration (eCO2), drought and elevated temperature (eT) on the leaf‐ to plant‐level WUE, covering 80 field studies and 95 tree species. The results showed that eCO2 increased leaf intrinsic and instantaneous WUE (WUEi, WUEt), whereas drought enhanced both leaf‐ and plant‐level WUEs. eT increased WUEi but decreased carbon isotope‐based WUE, possibly due to the influence of mesophyll conductance. Stimulated leaf‐level WUE by drought showed a progressing trend with increasing latitude, while eCO2‐induced WUE enhancement showed decreasing trends after >40° N. These latitudinal gradients might influence the spatial pattern of climate and further drove WUE variation. Moreover, high leaf‐level WUE under eCO2 and drought was accompanied by low leaf carbon contents. Such a trade‐off between growth efficiency and defence suggests a potentially compromised tolerance to diseases and pests. These findings add important ecophysiological parameters into climate models to predict carbon‐water cycles of forests.
Combined biochar and manure addition to an agricultural soil benefits fertility, microbial activity, and mitigates manure‐induced CO2 emissions
Authors: Lebrun Manhattan , Zahid Zubda , Bednik Magdalena , Medynska‐Juraszek Agnieszka , Száková Jiřina , Brtnický Martin , Holátko Jiří , Bourgerie Sylvain , Beesley Luke , Pohořelý Michael , Macků Jan , Hnátková Tereza , Trakal Lukáš
Published: November 2023

The importance of blending biochar into manure prior to its application as a soil amendment was investigated by this laboratory and field study, hypothesizing an (i) increase in soil fertility; (ii) improvement in microbial activity; (iii) reduction in manure‐induced CO2 emissions after combining amendments. Biochar was mixed with manure (50:50 V/V) and aged in field conditions for 6 months whereafter pristine biochar, manure, and manured biochar (50:50 V/V) were incorporated into an agricultural drought‐prone Regosol. All treatments and soil mixtures were incubated, with laboratory measurements of CO2 emissions taken using a coupled column respirometer set up, while nutrient availabilities as well as enzymatic activities were also tested. Demonstrable benefits of the biochar when blended to manure were exemplified in reduced CO2 emissions, by 60% compared with manure alone, and improved C and N acquisition by microorganisms. When applied to soil, blended biochar manure did not enhance CO2 emissions, but did significantly improve soil fertility by the avoidance of leaching of non‐plant consumed nutrients from the soil (e.g. NO3− by 58%). A significant increase in functional diversity indices in the presence of manured biochar highlights the added value of the blended approach. Field application yielded reduced effects; manure induced a higher carbon and nitrogen mineralization (thus potentially higher C and N emissions via CO2, CH4 and N2O) as well as a higher microbial functional diversity. Further studies should verify the effects observed here in a range of soil types and climates.
DRAG REDUCTION OF A SIMPLIFIED TRUCK MODEL USING CAB ROOF FAIRINGS
Authors: Ismadi Nurul Syamimi Zahirah , Mustaffa Ahmad Fikri
Published: November 2023

Adverse effects of climate change have prompt transition towards a low-carbon transportation sector. Electrification of the transportation sector is one of the ongoing efforts to reduce the Greenhouse Gas emissions. However, electrification of long haul and heavy-duty vehicles remain a huge challenge due to cost and limitation in the current battery technology. Improving the aerodynamic design of current truck-trailer is an alternative to electrification. This initiative involves modifying the current truck-trailer body design or attaching accessories for aerodynamic drag reduction that can lead to improved fuel economy. In this paper, the effectiveness of four Cab Roof Fairing (CRF) designs on the aerodynamic drag reduction of a simplified truck model is investigated. The results of a numerical simulation performed on a two-dimensional model show that the CRF can reduce aerodynamic drag by up to 45%. The CRF is found to reduce the vertical velocity component of the flow at fore part of the truck body. This leads to a relatively smaller wake region when compared against the baseline case. Wind tunnel results is performed to verify the results of the numerical simulation. At Reynolds number , the measured coefficient of drag reduction is about 6% when compared with the baseline case.
A DEEP LEARNING METHODOLOGY FOR PLANT SPECIES RECOGNITION USING MORPHOLOGY OF LEAVES
Authors: Barhate Deepti , Pathak Sunil , Kumar Dubey Ashutosh
Published: November 2023

Plants play a crucial role in supporting all forms of life on Earth, not just humans but every living organism. Understanding the diverse range of plant species that surround us is essential due to their significance in various aspects of human life, including agriculture, the environment, medicine, cosmetics, and more. Advancements in machine learning and computer vision algorithms have opened possibilities for identifying different types of plant species, both within and across classes. Plant species detection typically involves several steps, such as image acquisition, feature extraction, categorization, and pre-processing. In this study, three datasets—namely Flavia, Swedish, and the intelligent computing laboratory (ICL) dataset—were chosen for experimentation purposes. For feature extraction, three different models were employed: k-nearest neighbour (KNN), naive Bayes (NB), and the visual geometry group (VGG)-16 model. These models were used to extract distinctive features such as shape, texture, venation, and margin from the plant images. A multiclass classification task was conducted to categorize the plant species. Among the models tested, the VGG-16 model consistently demonstrated superior performance in terms of accuracy. Specifically, when using the VGG-16 model, the obtained accuracies were 96.68% for the Flavia dataset, 97.65% for the Swedish dataset, and 96.11% for the ICL dataset.
Conceptualization, Realization, and Validation of Distributed Cyber-Physical Systems for Sensing and Automation
Authors: Kwao Vincent , Workneh Hilina Tibebu , Raptis Ioannis
Published: December 2023

This paper investigates the feasibility of the pragmatic implementation of distributed algorithms in real-world cyber-physical systems (CPSs). We detail how distributed (and parallel) computing systems can be realized using existing system-design software for CPS development. A series of experiments is devised and used to verify the information-exchange capacity of the computing nodes and the synchronous and real-time operational effectiveness of the overall distributed computing system development framework. Finally, an actual distributed computing system is realized and validated by executing a fundamental distributed consensus protocol.
Experiment of Floating Seismic Isolation System
Authors: Mori Takashi , Shimada Takahiro , Kai Satoru , Otani Akihito , Yamamoto Tomohiko , Yan Xing L.
Published: November 2023

Experiment of a floating seismic isolation technology for application to small modular reactor (SMR) is conducted using a small-scale apparatus. The SMR is assumed to be located on land rather than offshore and installed on a newly proposed floating structure in pool. The floating structure is designed to mitigate the propagation of the horizontal component of seismic motion between the ground and the SMR buildings and to reduce the excitation force on the buildings caused by the vertical wave propagation through water. The floating structure design consists of a series of air cavities and orifices at the bottom of the structure. The underlining physics is to modify air volume modulus and damping ratio of the gaseous space under the floating structure that contribute to the propagation of seismic waves. Although experiments were conducted with both horizontal and vertical seismic input motions and the structure demonstrates significant effects of seismic reduction in both directions, only the results of experiment using vertical motions are discussed in this paper.
Microstructure-Sensitive Description of the Residual Stressability of Components With the Aid of Virtual Experiments
Authors: Neite Maximilian , Dölz Michael , Könemann Markus , Münstermann Sebastian
Published: November 2023

The application of macroscopic damage models is often made difficult by the fact that the calibration of the model parameters is associated with great experimental effort. Therefore, a methodological, simulative approach is presented to determine the damage model parameters with significantly less material input for the actual, local material state. Virtual experiments were performed on three-dimensional, statistically Representative Volume Elements (3D-RVE) of the microstructure to incorporate microstructure-based influences. For the generation of 3D-RVE, the in-house software DRAGen was used, which generated a geometric model based on input data gathered from EBSD analyses on the ferritic-bainitic reactor pressure vessel steel 22NiMoCr3-7. Mechanical properties were assigned to the constituents of the microstructure model by utilizing a phenomenological crystal plasticity model, which was inversely calibrated on the experimental flow curve. In addition, damage criteria on the microscale following the macroscopic material behavior are needed for cleavage and ductile fracture mechanism. Finally, the macroscopic damage model can be calibrated locally by micromechanical simulations. The virtual experiments were conducted with prescribed deformation boundary conditions, and different stress states were simulated by varying them.
Fractography of Neutron Irradiated RPV Steels – A Comparison of Shift in Reference Temperature and Net Hardening
Authors: Das Aniruddh , Chekhonin Paul , Houska Mario , Obermeier Florian , Altstadt Eberhard
Published: November 2023

Reactor pressure vessel (RPV) steels in nuclear reactors face embrittlement due to neutron irradiation. The embrittlement is associated with an increase in the reference temperature obtained via fracture toughness testing using the Master Curve concept. However, the fracture surfaces of some highly embrittled RPV steels exhibit ductile dimples. Through this work, we show that material properties, such as yield strength as a function of temperature, play an important role in determining the net hardening of a material. Additionally, we recorded the location of fracture initiators, using scanning electron microscopy (SEM) on the fracture surfaces of tested mini-C(T) specimens from four different RPV steels, to check whether it was affected by neutron irradiation and side grooving. We detected fracture initiators associated with high fracture toughness at greater distances to the crack tip. The locations of the fracture initiators changed significantly for samples with and without side-grooves and did not change significantly with respect to the irradiation state. We found the primary causes for increased ductility of embrittled RPV steels to be lower irradiation induced hardening and a higher loss in yield strength with increasing temperatures. Caution must therefore be exercised while interpreting the embrittlement of a material using ductile fracture surfaces alone.
Development of Conservative Material Properties to Account for Concrete Degradation Mechanisms With Specific Emphasis on Rebar Corrosion Due to Chloride Ingress
Authors: Browning K. M. , Hasa L. , de Haan-de Wilde F. H. E.
Published: November 2023

NPPs and research reactors built during the mid-20th century often have incomprehensive material characteristics of their concrete structures. This lack of quality records frequently leads to challenges when attempting to demonstrate safety during life extension projects or when specific modelling is necessary for portions of the plant when design regulations are updated with new or revised requirements.

In the framework of LTO there is limited knowledge about ageing and the structural integrity of concrete structures. In order to increase the knowledge in the field of civil structures, this paper focuses on investigating the ageing mechanisms of civil structures at NRG, Petten, and determining an appropriate chloride ingress model together with the alteration of concrete material properties to account for possible degradation effects. Knowledge of the ageing mechanisms of civil structures, especially concrete, will improve concrete’s ageing management and assessment methods.

The purpose of this research paper is to provide a methodology that can be used to account for possible concrete degradation. This will include a chlorine ingress model, calibrated to data obtained from the HFR chimney, that allows for the rebar reduction to be calculated. Furthermore, the design properties of concrete were determined in line with NEN-EN 1992-1-1:2004 [10] and NEN-EN 1990 [11] for specific concrete grades. The model generated will allow for user input if more detailed concrete properties are available for the area in question. This will allow the generation of area specific design properties for concrete that accounts for possible rebar reduction due to chloride ingress corrosion.

The report illustrates a methodology to account for chloride ingress during modelling by reducing the rebar diameter. It further demonstrates the importance of the assumed concrete properties as starting inputs to the chloride model and the calculated rebar reduction and generated internal pressure. The determined concrete properties, together with calculated rebar diameter reduction, are used to update the previously completed FEA of the HFR [1] and provide a comparison of the previous results when considering reduced concrete strength and rebar diameter. The actual rebar corrosion due to chloride ingress within the HFR is expected to be less as surface corrosion conditions are expected to be less.

In the future, more accurate material properties should be determined through physical measurement for the modelled slab. Further research and modelling can be completed to understand better steel corrosion failure in reinforced concrete with 3D FE analysis and measurements for chloride ingress in the HFR should be obtained.
Design Considerations for Pressure Vessels Containing a Top Mounted Agitator
Authors: Ebrahimi Kaveh , Millet Barry , Kirkpatrick Kenneth , Depner Jessica
Published: November 2023

Pressure vessels containing agitators supported by a nozzle on the vessel top cover are commonly used in a variety of industrial applications such as electric car battery material plants, metal refining plants, plastic recycling plants, food processing facilities, petrochemical plants and in the pharmaceutical industry.

The loads and moments induced by the agitator on both the top cover and the supporting nozzle are often cyclic in nature and it is common that these be ignored or only partially evaluated during the design of the vessel, especially when there may be time constraints or lack of resources. This can result in a shorter operating life for the agitator or its drive mechanism than originally expected, which could further lead to vibrational issues and subsequent fatigue failures in the top cover or the nozzle.

A correctly designed top cover and nozzle support for an agitator should be strong enough to withstand the sustained cyclic loads and contain features so it is acceptable for the cyclic conditions to allow the safe use of the equipment for the entirety of its intended design life.

The purpose of this paper is to firstly explain some of the recommended features that should be taken into account during the design and fabrication of agitator-mounted vessels and then to investigate a simple approach to estimate the fatigue damage on the nozzle. The suggested method will then be further examined against FEA results to ascertain its validity. British PD 5500 fatigue design rules will be considered for the evaluation.
Analysis of Fluid-Elastic Instability Models for Tube Banks With Square Arrangement in Cross-Flow
Authors: Neumeister Roberta Fátima , Petry Adriane Prisco , Möller Sergio Viçosa
Published: November 2023

The present study aims to compare experimental results with the existing models most applied to determine the critical reduced velocity in tube banks with a pitch ratio of 1.26 in a square arrangement and suggest adjustments considering the position of the cylinder free to vibrate. The experimental results were obtained in an aerodynamic channel using a tube bank test section with four and five rows. All the cases tested presented one cylinder free to vibrate in different positions inside a tube bank with the square arrangement. The experimental results showed the occurrence of fluid elastic instability for some cases, the critical reduced velocity changes with the position inside the tube bank, and the third row presents the lower reduced velocity. The results showed that the common models are quasi-static, quasi-steady, and quasi-unsteady. The quasi-steady and quasi-unsteady models presented conservative responses in the determination of the critical reduced velocity. The quasi-static model is conservative for some cases, while does not predict the fluid elastic instability for others. The experimental results showed that the critical reduced velocity reduces about 20% with the increase in the number of rows upstream of the cylinder free to vibrate.
Design Overview of Pressure Vessel Containment System for Proton Radiography of Shock Physics Experiments
Authors: Spernjak Dusan , Reichert Heidi , Ney Stephen , Venhaus Thomas
Published: November 2023

A system of nested pressure vessels is being developed to facilitate proton imaging of small-scale shock physics experiments at Los Alamos National Laboratory (LANL). Proton imaging provides valuable experimental data to characterize materials under extreme loading conditions. The main components of the nested system are the Inner Pressure Confinement Vessel (IPCV, which hosts the physics experiment), the Outer Pressure Containment Vessel (OPCV) and Beam Pipes and Auxiliary Hardware (BPAH). IPCV, OPCV, and BPAH together form a Pressure Vessel Containment System (PVCS).

The detonation of high explosives (HE) inside the IPCV drives material inside the physics experiment package to extreme loading conditions, which are imaged using a proton beam and an imaging system. The IPCV is an explosively loaded high-pressure vessel which is rigidly mounted into the OPCV. The OPCV is a statically loaded vacuum vessel, where the OPCV and beam pipes form the containment barrier and are under vacuum for the purpose of proton imaging. The OPCV bellows are connected to a rotary platform allowing linear and torsional movements within a range of motion for alignment of the OPCV/IPCV assembly within a fixed beamline. The OPCV is supported by a novel alignment system which allows six degrees of freedom of motion to locate the experiment package relative to the proton beam for precise imaging.

The IPCV is designed to the ASME Boiler and Pressure Vessel Code, Section VIII, Division 3, Code Case 2564. The aim is to make the confinement boundary Code-compliant while allowing for maximum resolution of proton radiography across a sufficiently large field of view. The OPCV is designed to ASME Boiler and Pressure Vessel Code, Section VIII, Division 1 with the allowance of Division 2 analysis per Mandatory Appendix 46 originating from Interpretation VIII-1-01-12 from BPVC Sec VIII-1 (2012). The nested vessels and beam pipes are connected to the Vacuum and Gas Handling System (VGHS). This paper provides an overview of the final design, analysis, and testing of the PVCS and its subassemblies.
Comprehensive Modelling of Pressurized Thermal Shock With a Probabilistic Approach
Authors: Pasti Fabio , Tajfirooz Sina , Uitslag-Doolaard H. J. , Brigante Francesco , De Haan-De Wilde F. H. E.
Published: November 2023

Pressurized thermal shock (PTS) may cause a quick, catastrophic cleavage fracture in a reactor pressure vessel (RPV) of a pressurized water reactor (PWR). Low temperatures, thermal strains, and radiation embrittlement can all combine to create dangerous situations for structures, specifically thick-walled reactor pressure containers with fractures and welds as weak areas. A thorough picture of the temperature and stress intensity is required to determine the likelihood of the onset and spread of a cleavage crack. The ductile to brittle transition temperature affects the critical stress intensity for brittle cleavage fracture. This complicated combination of loads, absolute temperatures, and temperature gradients is combined with radiation damage to evaluate the likelihood that cleavage fracture will occur. In earlier works, simulations were carried out using combined computational fluid dynamics (CFD) and finite element method (FEM) simulations to get the most realistic picture of this issue. However, due to the complexity of the problem, the thermal mixing of the fluid and its effects on the RPV wall are simulated by models that are simplified in terms of geometric complexity and physics. This study investigates the effect of the interaction between multiple emergency core cooling (ECC) plumes on the thermal response of the RPV wall by considering a full (360 degree) RPV geometry with two loops for the ECC fluid injection. We first perform a transient conjugate heat transfer CFD simulation to compute the spatial and temporal evolutions of RPV wall temperature. The unsteady Reynolds-averaged Navier-Stokes equations are solved on the fluid side, and the unsteady heat transfer equation is solved on the solid side.

Next, a static structural analysis using FEM is conducted using the temperature profile obtained from CFD analysis on a one-loop reactor as input. The goal of the FEM analysis is to investigate the link between the depth, length, and ratio of the crack and the probability of failure. A probabilistic approach is used to evaluate the possibility of failure. The ultimate goal of these studies is the generation of a code that can implement hydraulic models that replace the time and resource-demanding CFD and FEM analysis.
What Best Correlates to High Temperature Failure: Strain, Stress, Dissipation, or Something Else?
Authors: Hu Tianchen , Messner Mark C.
Published: November 2023

There are many damage models postulated in the literature to describe material failure at high temperatures under mechanical loading. Depending on the model, these failure theories describe creep rupture, fatigue failure, creep-fatigue failure, failure under monotonically increasing stress, or failures under all three types of loading. While there are many variations, often models of this sort fall into three general categories: those predominately governed by stress, those predominately governed by accumulated strain, and those predominately governed by dissipated energy. There is no consensus as to which of these general theories is most accurate, and this debate has a practical consequence on engineering design — the predominate high temperature design and fitness for service codes all use different high temperature damage and failure theories. This paper attempts to quantify which of these types of failure theories is most accurate by using machine learning techniques to (1) remove any dependence on the human-guided selection of a particular mathematical form for the failure theory by replacing the mathematical damage function with a deep neural network and (2) using machine learning feature selection techniques to have the computer automatically deduce which quantities best correlate to failure. We test these techniques against a high-quality dataset for high temperature failure in Alloy 617 which includes complete records of the experimentally measured strain, stress, and temperature as a function of time from the start of the test through the failure of the material. These data include a variety of test types and loading conditions, including tension, creep, fatigue, and creep-fatigue tests. The machine learning models trained in this study could be used to directly predict high temperature material failure, but also can help determine which of the simpler engineering failure theories most accurately correlates to experimental failure of the material.
Technical Basis for Inspection Optimization and Deferral of PWR Steam Generator Component Examinations
Authors: Cofie Nathaniel G. , Dedhia Dilip , Chesworth Scott T. , Shim Do Jun , Grizzi Robert
Published: November 2023

Pressurized water reactor (PWR) steam generator (SG) Class 1 and Class 2 components are required to be inspected every ten years by ASME Code, Section XI. A comprehensive survey of over forty years of examination results showed that no known degradation has occurred in these components. A comprehensive study involving stress analyses and probabilistic and deterministic fracture mechanics analyses indicated that the components are flaw tolerant and determined that the inspection of these components can be deferred beyond the current 10-year requirement without compromising plant safety.

A proposed Code Case has been introduced in ASME Code, Section XI that would allow the inspection of SG components to be deferred to 30 years from the date of the last inspection. Specifically, the Code Case addresses the following ASME Code, Section XI Examination Categories and Item Numbers:

• Class 1, Category B-B, pressure-retaining welds in vessels other than reactor vessels (Item Nos. B2.31, B2.32 and B2.40).

• Class 1, Category B-D, full penetration welded nozzles in vessels (Item No. B3.130).

• Class 2, Category C-A, pressure-retaining welds in pressure vessels (Item Nos. C1.10, C1.20 and C1.30).

• Class 2, Category C-B, pressure-retaining nozzle welds in pressure vessels (Item Nos. C2.21 and C2.22).

The technical bases for the proposed Code Case are provided in three EPRI reports (3002014590, 3002015906 and 3002023713). The first two reports were used by lead plants to request relief from the NRC for a 30-year deferral of the examination of the subject components. After many interactions with the NRC, relief was granted to the lead plants; however, the NRC also identified key parameters that should be considered in future requests. Lessons learned from interactions with the NRC were incorporated into the third report, which specifically addressed the 30-year deferral period with consideration of the key parameters identified by the NRC. This third report was only recently published and has not yet been used by a plant to seek relief for the 30-year deferral.

This paper provides the technical basis for the 30-year deferral of the examination of SG components in support of the proposed Code Case using the results of the evaluations in the three EPRI technical basis documents plus additional evaluations specifically addressing the 30-year deferral and the lessons learned through the Request for Alternative process by the lead plants.
Evaluation of the API 579-1/ASME FFS-1 KSSCCL1 and KSSCCL2 Stress Intensity Factors
Authors: Altstadt Steven , Sarzynski Melanie
Published: November 2023

The API 579-1/ASME FFS-1 2021 Fitness-For-Service stress intensity factor solution for a sphere with a surface crack, 360 Degrees, through-wall fourth order polynomial stress distribution (KSSCCL2) was independently investigated in this work. Axisymmetric, linear elastic finite element models of cracked spheres subjected to various applied stress fields were created and assessed. The objective was to estimate stress intensity factors (K) to evaluate crack-like flaws in spherical geometries using a parametric approach. The results were then used to calibrate the respective influence coefficient values (Gi). The sphere with a surface crack, 360 Degrees, internal pressure (KSSCCL1) uses the same table of influence coefficient values (Gi) and thus the new coefficients are also relevant to the KSSCCL1 scenario. A comparison of the newly calculated influence coefficient values to the existing values shows reasonable agreement for spheres with low ratios of internal radius to wall thickness (Ri/t). However, there is increasing discrepancy as the wall ratio increases, with the large differences predicted at Ri/t = 1000. The new influence coefficient values are recommended as an improvement for fitness for service assessments investigating 360-degree surface flaws in spherical geometries subject to fourth order polynomial through-wall stress fields (KSSCCL2) or internal pressure (KSSCCL1).
Artificial Neural Networks for Predicting Burst Strength of Thick and Thin-Walled Pressure Vessels
Authors: Johnson William R. , Zhu Xian-Kui , Sindelar Robert , Wiersma Bruce
Published: November 2023

The common use of pressure vessels (PVs) and pipelines and the high cost of their failure or overdesign in the oil and gas industry makes predicting their burst pressure critical. However, experimental tests of burst pressure are expensive and finite element analysis (FEA) is time consuming. Artificial neural networks (ANNs) hold the promise of rapid prediction of burst pressure for a wide range of PV materials and geometries, including pipelines with defects such as corrosion. This paper demonstrates ANNs designed and trained to accurately predict the burst pressure of both thick and thin-walled PVs for various strain hardening carbon steels. To accomplish this, we trained single and double hidden layer ANNs on experimental data, augmented with FEA, data of predicted burst pressure to create a larger database. A statistical study of hundreds of models exploring the key hyperparameters provided statistically optimal hyperparameters, resulting in highly accurate ANNs. The results, two ANNs with comparably low prediction error across geometries ranging from 3 < Do/t < 120, demonstrate the first use of ANNs to address both thick and thin-walled PV burst pressure within a single network. This is an important step towards designing ANNs for predicting the burst pressure of PVs and pipelines with defects.
Correct Use of Stainless Steel Bolts for Pressure Vessel Applications
Authors: Shargay Cathleen , Daru Kuntak , Gala Punita , Panchal Anilkumar
Published: November 2023

Stainless steel bolts are sometimes specified for pressure vessel applications which are designed according to ASME Section VIII, Div. 11 or Div. 22. The design of the flanges and bolting falls under ASME B16.53 and B16.474 for standard flanges, and under Mandatory Appendix 2 and Para. 4.16 of Division 1 and Division 2 respectively for designed flanges. Stainless bolts have various grades and classes based on material and heat treatment, and size requirements. If special service requirements apply such as meeting NACE standards for wet sour services (namely NACE MR0175 or MR0103)5,6, it can become impossible to meet both the Code and NACE requirements with stainless steel bolts in many situations.

This paper provides information as follows.

1. The paper incorporates flow charts outlining selection of stainless bolts for flanges on pressure vessel to be constructed according to ASME Section VIII, Divisions 1 and 2.

2. Discusses material test requirements and size limits applicable for each class of stainless bolts used on standard and custom designed flanges.

The paper will help the Code user to select proper grade and type of stainless bolts and avoid non-compliances.
Comparison Between Fracture Mechanics Evaluation Methods in ASME Boiler & Pressure Vessel Code, Section XI and Those in JSME Leak-Before-Break Evaluation Guidelines for Sodium-Cooled Fast Reactors
Authors: Yada Hiroki , Takaya Shigeru , Machida Hideo
Published: November 2023

ASME Boiler and Pressure Vessel Code (BPVC), Section XI, Division 2 provides requirements for protecting passive components that affect reliability of the plant. It generally consists of technology-neutral common requirements, and additional ones for individual reactor types. Currently, an Appendix for sodium-cooled fast reactors (SFRs) is being developed based on Code Case N-875. In the Code Case, continuous leakage monitoring was employed as inspection method for components retaining liquid sodium. It is also important to introduce leak-before-break (LBB) assessment procedures in the Appendix because demonstration of LBB is necessary to show the adequacy of applying continuous leakage monitoring to the component of interest. However, LBB assessment method is not provided in ASME BPVC. On the other hand, recently, LBB assessment guidelines for SFRs has been developed by the Japan Society of Mechanical Engineers (JSME). It could be used to prepare LBB assessment procedures for the Appendix, but it needs to confirm the consistency with ASME BPVC Sec. XI. In this study, fracture evaluation methods for pipes with through-wall flaw are compared between the JSME LBB assessment guidelines and applicable evaluation method in ASME BPVC Sec. XI, Div. 1. There are limit load criteria and failure assessment diagram (FAD) approaches in both of them. Allowable flaw size evaluation methods in limit load criteria are almost same. In FAD approach, some differences exist. The FAD approach in the JSME LBB assessment guidelines is based on the R6 defect assessment procedures option 3 and constructed to be consistent with the Fitness-forservice code for light water reactors in JSME. In this study, fracture evaluation methods related to LBB assessment were compared in preparation for introducing LBB assessment procedures into ASME BPVC Sec. XI, Div. 2. Furthermore, effects of the differences were investigated. As a result, it was shown that there was not any significant difference between them except for the structural factors which need to be determined by considering the consistency with related provisions in individual codes.
Development of a Graphite Irradiation Qualification Plan for the XE-100 Reactor
Authors: Campbell Anne A. , Geringer Josina W. , Schrell Adrian M. , Baylis Samuel , Lucas Timothy , Pappano Peter J. , van Staden Martin
Published: November 2023

The American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section III “Rules for Construction of Nuclear Facility Components”, Division 5 “High Temperature Reactors”, Subsection HH “Class SN Nonmetallic Core Components”, Subpart A “Graphite Materials”, has a list of materials properties that must be measured and included in the materials data sheet (MDS) for each grade of graphite to be used in a reactor core. Two sections of the MDS includes measuring the effects of degradation, due to oxidation or neutron irradiation damage, on these materials properties. A program at Oak Ridge National Laboratory (ORNL), supported by X Energy, LLC., began in 2017 to produce the irradiation-induced property change results of graphite grades that will be used in the X Energy Xe-100 small modular reactor. Significant effort has been performed around the world to capture these property changes for a range of graphite grades through both the US Advanced Graphite Creep program, and the EU INNOGRAPH/ARCHER program. But both programs were primarily targeted towards higher temperature reactor designs that were of greater importance at the beginning of both programs resulting in a lack of data for temperatures below 600°C. The program at ORNL has been developed to produce the data necessary to assist with completing the irradiation effects on materials properties of the MDS for the graphite grades of interest for X Energy. This paper will discuss the design of the irradiation program including the irradiation conditions (neutron fluence and irradiation temperatures), the types of specimens being used in this program, and the irradiation methodology.
Path Forward: Materials Data Modernization for ASME Codes and Standards in the Artificial Intelligence Era
Authors: Ren Weiju
Published: November 2023

Development of the ASME Materials Properties Database was initiated in the early 2010s to support the ASME Codes and Standards. As information technologies advance at an accelerated pace with the artificial intelligence era on the horizon, the ASME Materials Properties Database must be further modernized from a database to a knowledgebase to ride the wave of digital information revolution and effectively support the ASME Codes and Standards in the new era.

This paper is intended to provide an overview of the ASME Materials Properties Database and discuss a roadmap for its future development to facilitate understanding of and participation from different sectors of the Codes and Standards community. It first reviews the basic concepts of data, information, knowledge, database, and database system; as well as the pros and cons in different types of data management, and then discusses the path forward for a desired evolution of the database into a self-explanatory and machine-readable knowledgebase that is consistent with human cognitive processes for the Codes and Standards development and furthermore provides resources for data processing and analysis to reach an eventual goal of streamlining the Codes and Standards development from the initial inquiry, throughout data submission, analysis, ..., to Codes and Standards rule establishment for final publication.
Fatigue Property Evaluation of Metallic AM Parts and Determination of Design Stress Allowables
Authors: Dong Pingsha , Rawls George , Krentz Tim
Published: November 2023

As additive manufacturing (AM) is being adopted for cost-effectively fabricating metallic parts for safety-critical components subjected to fatigue loading, one of the major challenges has been on how to address structural significance of spatially distributed geometric discontinuities. To address some of the issues for pressure equipment applications, a DOE project was initiated to develop a robust metal AM flaw assessment methodology, aiming to examine the feasibility of extracting fatigue design stress allowable. This study was carried out in conjunction with ASME’s BPTCS/BNCS committee activities with test data both provided by some committee member organizations and resulted from a comprehensive literature search. This paper highlights both the technical approach adopted and major findings to date, including: (1) The master S-N curve (or E-N curve) method adopted by ASME BP&V Div 2 Code seems to provide an effective framework for extracting fatigue design stress allowable for fatigue evaluation for AM components; (2)A cost-effective AM flaw acceptance criterion can be implemented by identifying fatigue-critical locations or hot spots as defined in this study for a set of four typical components. (3) Fitness for Service (FFS) methodologies are shown effective in quantitatively establish flaw acceptance criteria for these hot spot locations.
Impact Test Exemption Temperature Reduction of SA-193 B16 Studs for Cold Climate Installations
Authors: Hioe Yunior , Orth Fabian , Bagnoli Kenneth , Moncayo Sabastian
Published: November 2023

SA-193 B16 studs are more cost effective and more reliable in high temperature equipment applications than B8 studs, however B16 stud applications are currently limited in a significant portion of North American and other places in the world colder climates due to the current −20F (−30C) impact test exemption temperature in ASME Section VIII, B31, and FFS-1. Furthermore, MDMT adjustments are not permitted for studs due to preload [e.g., UCS-66(b)]. ASME BPVC Section VIII Division 1 specifies an impact test exemption temperature for SA-193 B7 of −55F (−48C) for up to 2 ½” (64 mm) studs, whereas SA-193 B16 studs have a higher impact test exemption temperature of −20F (−30C) up to 7” (175 mm) studs.

The similar material and chemical properties of B16 and B7 studs (both SA-193) give reason to believe that both stud types should exhibit similar fracture toughness properties at low temperatures. Two-phase research and testing programs have been running for the past few years. The initial research and testing were performed on one sample material to determine if the MDMT for B16 and B7 studs was similar at low temperatures for small diameters. Part of this feasibility study involved developing impact test transition curves through Charpy impact testing, as well as fracture toughness testing, which will be detailed in this paper.

Then the second part of the program was about statistical sampling with material sourced from around the world.
Finite Element Model Mesh Refinement Effects on Qualification of Nuclear Grade Graphite Components
Authors: Mack Andrea , Hoffman William , Bass Joseph , Windes William
Published: November 2023

The American Society of Mechanical Engineers (ASME) provides the full and simplified design-by-analysis probabilistic assessments for determining acceptance of nuclear grade graphite core components. The assessments can be characterized by three parts: (1) a component stress distribution, often determined by a finite element (FE) model; (2) a Weibull probability density function (pdf) that characterizes the experimental tensile strength distribution; and (3) the postprocessor, which combines the FE model and the Weibull strength distribution in accordance with the full and simplified assessments to determine component acceptance. It is known that the level of mesh refinement in FE models can affect the modeled component’s calculated stress distribution. Depending on the component geometry, the stress distribution may converge with sufficient refinement. It was previously unknown whether the acceptance decision resulting from the full and simplified assessments might change even with sufficient mesh refinement. This study explores that question using experimental strength results for a dog-bone geometry for two graphite grades, IG-110 and PCEA. The simplified assessment has two criteria that must be met, the first limits the combined membrane stress by the allowable stress and the second limits the peak equivalent stress by the allowable stress scaled by the ratio of flexural to tensile strength. In the application of the simplified assessment, convergence of the peak equivalent stress required extreme mesh refinement, however, the acceptance decision was not affected. It is hypothesized that more complex geometries with stress concentrations may present mesh refinement effects on the simplified assessment acceptance decision. Mesh refinement did affect the acceptance decision in the full assessment for the applied pressure loadings in this study. This work suggests component stress distribution convergence is not a sufficient criteria for POF convergence in the full assessment and that mesh refinement should continue until the POF has converged, especially where the resulting POF is bordering the SRC acceptable POF limit.
Suggested Improvements to ASME Code Section XI, Nonmandatory Appendix L Flaw Tolerance Approach
Authors: Scott Alexandria , Udyawar Anees , Coleman Joshua , Glunt Nathan
Published: November 2023

The current requirements in ASME Section XI, 2021 Edition, Nonmandatory Appendix L provide guidance for evaluation of components when fatigue usage limits have been exceeded or fatigue usage is predicted to be of concern. As plants apply for subsequent license renewal (SLR), and in turn, fatigue accumulates on components within the reactor coolant system (RCS), flaw tolerance evaluations based on the guidance in Section XI Appendix L become increasingly necessary to assess fatigue. Through these evaluations and recent discussion during the ASME Section XI Task Group on Appendix L at the ASME Code Meetings, the following improvements to Section XI Appendix L are suggested: 1) add a tiered evaluation process for circumferential flaw shapes by first postulating a 360 degree flaw length and determining acceptability for piping components, before needing to move into the Equivalent Single Crack (ESC) aspect ratio tables that are already provided in Section XI Appendix L, and 2) clarify axial flaw procedures for postulated flaw shape in longitudinal welded seam ferritic pipes and austenitic pipes, as well as axial flaws postulated in seamless ferritic pipes and austenitic pipes (i.e., circumferential welds). This paper provides perspective of the impact of the suggested improvements to ASME Code Section XI Nonmandatory Appendix L flaw tolerance approach.
Broadband sound absorption based on impedance decoupling and modulation mechanisms
Authors: Mei Zhongjian , Li Xiaodong , Lyu Yadong , Sang Jinqiu , Cheng Xiaobin , Yang Jun
Published: November 2023

In sound absorbers, acoustic resistance and reactance are usually coupled together and affect each other, which brings difficulties to impedance matching. An impedance decoupling method is proposed to make acoustic resistance and acoustic reactance vary independently. For the same thickness and perforation rate, acoustic reactance of the perforated panel with tube bundles (PPTBs) varies with the diameter of the tube, but acoustic resistance remains constant. Theoretical and simulated results show that a PPTB absorptive unit can exhibit resonance modes with varying damping states through impedance decoupling. It is found that through well-modulation, the PPTB unit in a slightly over-damped state cannot only maintain high sound absorption coefficients, but also expand the absorption peak bandwidth. Utilizing the mechanism of impedance decoupling, a broadband absorber is designed and evaluated by comprising the PPTB and microperforated panel (MPP). Measurement results indicate that it possesses an average absorption coefficient of 85% spanning more than a 3-octave bandwidth from 160 Hz to 1400 Hz with a deep sub-wavelength thickness. The impedance decoupling method helps to implement sound absorbers with highly efficient low-frequency broadband absorption.