bluuebunny/crossref_metadata_2025_split huggingface dataset:
Outline of the Recent Consolidated Revision of EN13445-3, Clause 18 and Related Annexes: Detailed Assessment of Fatigue Life
Authors: Rudolph Jürgen , Baylac Guy , Trieglaff Ralf , Gawlick Rüdiger , Krämer Michael , Simonet Yves , Triay Manuela 
Published: November 2019

Abstract
The European Pressure Vessel Standard EN 13445 (harmonized Standard acc. to PED 2014/68/EU) provides in its Part 3 (Design) a simplified method for fatigue assessment (Clause 17) and a detailed method of fatigue assessment (Clause 18). While the new revision of Clause 17 has already been adopted, Clause 18 “Detailed Assessment of Fatigue Life” is now available as a consolidated revision in inquiry phase. This major and comprehensive revision has been developed within the framework of the European working group CEN/TC 54/WG 53 – Design methods and constitutes a crucial step towards a modern and user-friendly engineering fatigue assessment method. The overall structure and amendments of Clause 18 are to be presented. All these amendments aim at a significant increase in user friendliness and clear guidelines for application. The following items are to be mentioned in that context:
• Fatigue assessment of welded components based on structural stress and structural hot-spot stress approaches,
• Detailed guidelines for determining relevant stresses and stress ranges,
• Cycle counting proposals in the context of the fatigue assessment method including a critical plane approach.
The fatigue assessment of welded components is separated from the fatigue assessment of un-welded parts as it has already been done in previous versions with respective methodological differences. Stress analyses for clause 18 are usually based on detailed finite element analyses (FEA). As an essential amendment for the user, the determination of structural stress ranges for the fatigue assessment of welds is further detailed in a new appropriate annex.
Different applicable methods for the determination of structural stresses are explained in connection with the requirements of the finite element models and analyses. The cycle counting issue is comprehensively treated in the context of different design and operation situations (design transients, operational stress-time-histories). The description is detailed towards a critical plane approach. Detailed proposals for implementation in an algorithmic programming framework are given making the described methods ready to use.
New Leakage Requirements for ASME B16.20 and Current Generation Spiral Wound Gaskets
Authors: Bausman Anita , Waterland Jerry , Reid Dan 
Published: November 2019

Abstract
The ASME B16.20 Metallic Gaskets for Pipe Flanges standard was extensively revised in 2017 [1]. One of the significant changes is the introduction of maximum permissible leakage rate. This marks a landmark introduction of an actual leakage performance criterion into ASME B16.20, a most welcome advance. A common maximum permissible leakage rate of 0.0137 mg/s-m (7.67E−10 lb/s-in) is specified for all sizes and pressure classes of finished spiral wound gaskets, that is, including the windings and any or no gauge rings for that particular gasket. Test conditions are defined — ambient temperature and calibration gas with a known methane concentration and flow rate of 1 L/min. The test pressure is defined by the pressure class: 20 bar (290 psi) for Class 150 and 40 bar (580 psi) for Class 300 and above. The qualification parameters listed in B16.20-2017 include prescribed gasket seating stress targets which also vary by pressure class. These gasket seating stress requirements are defined as 35 MPa (5,000 psi) for Class 150, 56 MPa (8,000 psi) for Class 300 and Class 400, and 70 MPa (10,000 psi) for Class 600 and above. Three questions will be explored in this paper. First, to what tightness does the new B16.20 spiral wound gasket leakage rate criterion correspond? Second, do current generation spiral wound gaskets meet this criterion? Several commercially available spiral wound gaskets will be analyzed and compared to the new B16.20 requirements. Leak rates and tightness at the new B16.20 performance qualification test conditions can be determined using publicly available, published Room Temperature Tightness (ROTT) test constants for these gaskets. Finally, an exploration of Assembly Tightness compared to Operating Tightness for a selection of spiral wound gaskets will be presented and compared to the new B16.20 Performance Testing requirements. This exploration of the new maximum leakage performance criterion in ASME B16.20-2017 will help to familiarize the end user with a valuable new aspect of this gasket standard as well as how the current generation of spiral wound gaskets meets that criterion using publicly available ROTT performance data.
Engineering J Estimates for Spent Fuel Canisters Under Combined Mechanical and Welding Residual Stresses
Authors: Lee Hyun-Jae , Kim Yun-Jae , Lam Poh-Sang , Sindelar Robert L. 
Published: November 2019

Abstract
This paper compares engineering J estimates for Spent Fuel Canisters (SFCs) under combined mechanical and welding residual stress (WRS) with finite element (FE) results. Engineering J estimates are based on reference stress method provided in the R6 procedure considering interaction between primary and secondary stresses using the V-factor. It is found that residual stress should be considered in fracture assessment and the R6 estimates are reasonably conservative compared to FE analysis results.
Bolted High Pressure Girth Flange Connections
Authors: Hantsch Christoph 
Published: November 2019

Abstract
Besides metallic lens ring gaskets for piping applications the high-pressure processes for LDPE production also require gaskets for bolted girth flange connections. A typical application is the 380 bar (5500 psi) head to tubesheet connection of a recycle gas cooler for the LDPE production process. The most common gasket types for this application are either solid ring or spring energized seals. During startup of an LDPE tube-reactor severe ethylene leaks occurred even though the flanged connection had successfully passed the hydrotest at the fabrication shop. A detailed investigation supported by the exchanger fabricator, gasket manufacturer and LDPE process licensor found that connections having line contact stress need to be treated differently from commonly known surface pressure based flat gasket connections. In this paper the author explains the basic considerations for leak tight flange design using spring energized gaskets supported by FEA based root cause leak investigation results. Conclusions are drawn about the appropriate limits for deflection of flanges as compared to results using bolted flat gasket types like Kammprofile gaskets.
Leak Rates Through Complex Crack Paths: Update on the Latest Developments From the European Project ATLAS+
Authors: Gill Peter , Nicak Tomas , Daniels Brian , Obermeier Florian 
Published: November 2019

Abstract
Leak-before-Break assessments require a reliable method to obtain leakage rates from narrow cracks. The ability to predict leakage accurately is crucial to the overall success of Leak-before-Break arguments as the detection capability and limiting crack size are often very small. This can make it difficult to achieve the desired margin between limiting defect size and the crack size required for detectable leakage. The resulting narrow flow paths (&lt; 0.1mm) relative to the wall thickness (&gt; 10mm) necessitates the use of complex thermodynamic and friction models in the leak rate calculation.
A method to calculate leakage rates through complex paths was presented in PVP2015-45468 using an ordinary differential equation (ODE) for Mach number. This model was developed to account for crack opening displacements that vary non-linearly through the wall of a pipe. This situation typically arises when there is a through wall crack at a weld, where significant residual stresses are present. This paper considers an FEA model of a plate with a weld residual stress (WRS) profile applied. The WRS is prescribed with nodal displacements, and the COD is calculated from post processing of the elastic stress analysis solution. This results in a COD function in terms of the distance through the wall, which can then be used in the leak rate calculation. Comparisons are made with the R6 methodology recommended software DAFTCAT and the benefits of using the ODE method are discussed.
In collaboration with Framatome, Germany, a test case based on the previous European project STYLE was considered. The test case involves a Type 316L Stainless Steel pipe with a girth weld, and the FEA model includes postulated through wall defects at the weld interface to assess crack opening displacements. This model will be used to extract crack opening displacements and calculate leak rates using various methods. Two phase flow will be considered for this test case as the pipe geometry is very relevant to PWRs.
Evaluation of the Effect of Internal Pressure and Flaw Size on the Tensile Strain Capacity of X42 Vintage Pipeline Using Damage Plasticity Model in Extended Finite Element Method (XFEM)
Authors: Agbo Sylvester , Lin Meng , Ameli Iman , Imanpour Ali , Duan Da-Ming , Cheng J. J. Roger , Adeeb Samer 
Published: November 2019

Abstract
Pipelines subjected to displacement-controlled loading such as ground movement may experience significant longitudinal strain. This can potentially impact pipeline structural capacity and their leak-tight integrity. Reliable calibration of the tensile strain capacity (TSC) of pipelines plays a critical role in strain-based design (SBD) methods. Recent studies were focused mostly on high toughness modern pipelines, while limited research was performed on lower-grade vintage pipelines. However, a significant percentage of energy resources in North America is still being transported in vintage pipelines. Eight full-scale pressurized four-point bending tests were previously conducted on X42, NPS 22 vintage pipes with 12.7 mm wall thickness to investigate the effect of internal pressure and flaw size on TSC. The pipes were subjected to 80% and 30% specified minimum yield strength (SMYS) internal pressures with different girth weld flaw sizes machined at the girth weld center line. This paper evaluates the TSC of X42 vintage pipeline by utilizing ductile fracture mechanics models using damage plasticity models in ABAQUS extended finite element method (XFEM). The damage parameters required for simulating crack initiation and propagation in X42 vintage pipeline are calibrated numerically by comparing the numerical models with the full-scale test results. With the appropriate damage parameters, the numerical model can reasonably reproduce the full-scale experimental test results and can be used to carry out parametric analysis to characterize the effect of internal pressure and flaw size on TSC of X42 vintage pipes.
Stress Intensity Factors for Layered Pressure Vessel Inner Layer Through Cracks
Authors: Hobbs Joel R. 
Published: November 2019

Abstract
A difficulty encountered when performing Fitness-for-Service assessments for layered pressure vessels (LPVs) is the lack of stress intensity factor solution in literature that produce accurate results for inner layer longitudinal through cracks. Using surrogate solutions such as a through crack in a plate or cylinder produce results that can be overly conservative especially for longer cracks. This is largely due to the ability of a layered pressure vessel to redistribute hoop load to other layers, the restricted radial movement of the cracked layer, and the friction forces applied in the cracked region.
To understand this problem, a parametric finite element model (FEM) generator was developed that is capable of producing layered pressure vessel models with inner layer through cracks. The results from the FEMs were used to create a dataset of inner layer through crack stress intensity factors (Ki) for layered pressure vessels corresponding to variations of internal pressure, radius, layer thicknesses, friction factor, and crack length. The elastic modulus of the material also has an effect on Ki but, for this dataset, the elastic modulus was fixed at the typical value for steel – 29,500 ksi (203 GPa).
Finally, a non-dimensional model was developed and calibrated using the dataset. This allows Ki to be calculated without the need of a FEM using a closed-form equation. The results of the closed-form solution were then compared to FEM results showing accuracy was generally within 10%.
Data Analysis and Model Validation of Natural Gas Transmission Pipeline With Compressor Station
Authors: Cheng David 
Published: November 2019

Abstract
Data from the DCS systems provides important information about the performance and transportation efficiency of a gas pipeline with compressor stations. The pipeline performance data provides correction factors for compressors as part of the operation optimization of natural gas transmission pipelines.
This paper presents methods, procedure, and a real life example of model validation based performance analysis of gas pipeline. Statistic methods are demonstrated with real gas pipeline measurement data. The methods offer practical ways to validate the pipeline hydraulics model using the DCS data. The validated models are then used as performance analysis tools in evaluating the fundamental physical parameters and assessing the pipeline hydraulics conditions for potential issues influencing pressure drops in the pipeline such as corrosion (ID change), roughness changes, or BSW deposition.
Prediction of Structural Reliability Through an Alternative Variability-Based Methodology
Authors: Haas Kyle 
Published: November 2019

Abstract
Astonishing increases in computational power have fueled the engineering community’s drive to seek increasingly optimized solutions to structural design problems. Although structural optimization can be critical to achieve a practical and cost-effective design, optimization often comes at a cost to reliability. The competing goals of optimization and reliability amplify the importance of validation, verification, and uncertainty quantification efforts to achieve sufficiently reliable performance. Evaluation of a structural system’s reliability presents a practical challenge to designers given the potentially large number of permutations of conditions that may exist over the full operational lifecycle. A direct prediction of performance and the prediction’s corresponding likelihood is often achieved via deterministic analysis techniques in conjunction with Monte Carlo analysis. Such methods can be overly cumbersome and often do not provide a complete picture of the system’s global reliability due to the practical limits of performing the necessary number of analyses. At the point of incipient structural failure, the structural response becomes highly variable and sensitive to minor perturbations in conditions. This characteristic provides a powerful opportunity to determine the critical failure conditions and to assess the resulting structural reliability through an alternative, but more expedient variability-based method. Non-hierarchical clustering, proximity analysis, and the use of stability indicators are combined to identify the loci of conditions that lead to a rapid evolution of the structural response toward a failure condition. The utility of the proposed method is demonstrated through its application to a simple nonlinear dynamic single-degree-of-freedom structural model. A feedforward artificial neural network is trained from numerically-generated data to provide an expedient means of assessing the system’s behavior under perturbed conditions. In addition to the L2-norm, a new stability indicator is proposed called the “Instability Index”, which is a function of both the L2-norm and the calculated proximity to adjacent loci of conditions with differing structural response. The Instability Index provides a rapidly achieved quantitative measure of the relative stability of the system for all possible loci of conditions.
Risk Assessment for Model and Simulation Credibility Characteristics
Authors: Madry John G. , Elele James N. , Hall David H. , Turner David J. 
Published: November 2019

Abstract
The Department of Defense (DoD) uses the principles of risk assessment extensively throughout the acquisition process to identify, manage, and mitigate risk in many areas including software (both simulation software and software embedded in materiel systems). The approach to assessing the risks associated with using results from Models and Simulations (M&S) to influence decision-making that is described here is used by the Naval Air Systems Command (NAVAIR) 5.4H Verification, Validation, and Accreditation office.
The focus of the risk assessment is on ten specific characteristics of M&S Capability, Accuracy, and Usability that have the most potential impact on the intended uses. In this method, the characteristics of the M&S are evaluated against standard criteria, and then assigned a color-rating of Green, Yellow, or Red based on the actual data obtained from the M&S itself. A simple computation is then used to weigh the ratings of the characteristics into the likelihood of error aspect of the risk of using the M&S. A thorough understanding of the M&S and its application is a prerequisite to using this approach since the analyst is required to provide a technical justification for the rating assigned to a characteristic. Should the assigned rating for a characteristic of the M&S not be green, the analyst is required to recommend actions and/or mitigations for the M&S developer to take that would improve the rating to green.
Comparison of four decision aids for the early diagnosis of acute coronary syndromes in the emergency department
Authors: Body Richard , Morris Niall , Reynard Charles , Collinson Paul O 
Published: November 2019

ObjectivesTo directly compare the diagnostic accuracy of four decision aids (Troponin-only Manchester Acute Coronary Syndromes (T-MACS), History, ECG, Age, Risk factors and Troponin (HEART), Thrombolysis in Myocardial Infarction (TIMI) and Emergency Department Assessment of Chest Pain (EDACS)) used to expedite the early diagnosis of acute coronary syndromes (ACS) in the ED.MethodsWe prospectively included patients who presented to 14 EDs in England (February 2015 to June 2017) with suspected ACS within 12 hours of symptom onset. Data to enable evaluation of the T-MACS, HEART, TIMI and EDACS decision aids (without recalibration) were prospectively collected, blinded to patient outcome. We tested admission blood samples for high-sensitivity cardiac troponin I (hs-cTnI; Siemens ADVIA Centaur). Patients also underwent serial cardiac troponin testing over 3–12 hours. The target condition was an adjudicated diagnosis of acute myocardial infarction (AMI). We also evaluated the incidence of major adverse cardiac events (including death, AMI or coronary revascularisation) at 30 days. Diagnostic accuracy of each decision aid and hs-cTnI alone (using the limit of quantification cut-off, 3 ng/L) was evaluated by calculating sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).ResultsOf 999 included patients, 132 (13.2%) had AMI. C-statistics were 0.96 for T-MACS, 0.78 for HEART and 0.69 for TIMI. The sensitivities of T-MACS, HEART, TIMI, EDACS and hs-cTnI <3 ng/L for AMI were 99.2% (95% CI 95.7% to 100.0%), 91.8% (85.0% to 96.2%), 97.5% (92.9% to 99.5%), 96.2% (92.2% to 99.4%) and 99.2% (95.9% to 100.0%), respectively. The respective strategies would have ruled out 46.5%, 34.9%, 19.4%, 48.3% and 28.8% patients. PPVs for the decision aids that identify ‘high-risk’ patients were 80.4% (T-MACS), 51.9% (TIMI) and 37.2% (HEART).ConclusionsIn this study, T-MACS could rule out AMI in 46.5% patients with 99.2% sensitivity. EDACS could rule out AMI in 48.3% patients with lower sensitivity, although the difference was not statistically significant. The HEART and TIMI scores had lower diagnostic accuracy.
The effect of flavoured and non-flavoured tobacco on subjective experience, topography and toxicant exposure among waterpipe smokers
Authors: Ben Taleb Ziyad , Vargas Mayra , Ebrahimi Kalan Mohammad , Breland Alison , Eissenberg Thomas , Brown David , Maziak Wasim 
Published: November 2019

IntroductionFlavoured waterpipe (WP) tobacco is a major factor in the resurgence of WP smoking and a main attractant of WP use among youth. Yet, evidence of the effects of limiting flavour on WP smoker’s experiences and exposures is limited. This study examined the impact of flavour manipulation on WP smokers’ toxicant exposure and smoking experiences.MethodA total of 144 WP smokers attended two, 45 min ad libitum smoking sessions (flavoured vs non-flavoured tobacco) in a crossover design study. Participants completed a battery of questions assessing subjective smoking experiences. Exhaled carbon monoxide (eCO) and plasma nicotine concentrations were measured before and after the smoking sessions. Puff topography was recorded throughout the smoking sessions.ResultsCompared with the non-flavoured WP tobacco, participants reported enhanced subjective smoking measures of satisfaction and enjoyment following smoking flavoured WP tobacco (ps <0.05). Although participants spent a longer time smoking flavoured tobacco, they took on average larger puffs while smoking the non-flavoured tobacco (ps <0.05). Greater levels of eCO were recorded following the non-flavoured tobacco session (p<0.05) compared with flavoured tobacco. No significant differences were observed in plasma nicotine concentrations between the two tobacco conditions. WP harm perception was higher among participants after smoking non-flavoured WP tobacco compared with their preferred flavour (p<0.05).ConclusionSmoking the flavoured tobacco product was associated with enhanced subjective experiences compared with the non-flavoured, suggesting a potential role for flavour regulation in reducing WP use. Mixed results were observed for toxicants exposure in relation to smoking flavoured compared with non-flavoured products suggesting the need for a more comprehensive assessment of the effects of other tobacco constituents and additives on toxicant exposure in WP smokers.
KK Higgs produced in association with a top quark pair in the bulk RS model
Authors: Manglani N. , Misra A. , Sridhar K. 
Published: November 2019

AbstractWe present a search strategy for the first Kaluza–Klein (KK) mode of the Higgs boson in the framework of the Randall–Sundrum (RS) model with a deformed metric. We study the production of this massive excitation in association with a $$ t {\bar{t}}$$tt¯ pair at the large hadron collider (LHC). The KK Higgs primarily decays into a boosted $$t {\bar{t}}$$tt¯ final state and we then end up with an interesting four-top final state of which two are boosted. The boosted products in the final state improve the sensitivity for the search of the KK Higgs in this channel whose production cross-section is otherwise rather small. Our results suggest that masses of the KK Higgs resonance upto about 1.2 TeV may be explorable at the highest planned luminosities of the LHC. Beyond this mass, the KK Higgs cross-section is too tiny for it to be explored at the LHC and may be possible only at a future higher energy collider.