bluuebunny/crossref_metadata_2025_split huggingface dataset:
Worsening racial disparity in waitlist mortality for pediatric heart transplant candidates since the 2016 Pediatric Heart Allocation Policy revision
Authors: Wright Lydia K. , Gajarski Robert J. , Phelps Christina , Hoffman Timothy M. , Lytrivi Irene D. , Magnetta Defne A. , Shaw Fawwaz R. , Thompson Consuela , Weisert Molly , Nandi Deipanjan 
Published: November 2022

AbstractBackgroundThe US Pediatric Heart Allocation Policy (PHAP) was revised in March 2016, with the goal of reducing waitlist mortality. We evaluated the hypothesis that these changes, which increased status exceptions, have worsened racial disparities in waitlist outcomes.MethodsChildren in the Pediatric Heart Transplant Study database listed for first heart transplant from January 2012 – June 2020 were included and stratified by listing before (Era 1) or after (Era 2) the PHAP revision.ResultsA total of 4,089 children were listed during the study period. Compared with white children (n = 2648), non‐white children (n = 1441) were more likely to have an underlying diagnosis of cardiomyopathy in both eras. Waitlist mortality was similar in white and non‐white children in Era 1, but comparatively worse for non‐white children in Era 2. In multivariable analysis controlling for diagnosis, age, and severity markers, non‐white children had a significantly higher waitlist mortality only in Era 2 (Era 1: sHR 1.22 [95%CI 0.90 – 1.66] vs. Era 2: sHR 1.57 [95%CI 1.17 – 2.10]).ConclusionsWidening racial disparities in waitlist mortality may be an unintended consequence of the 2016 PHAP revision. Additional analyses may inform the degree to which this policy vs. unrelated changes in care differentially contribute to these disparities.
Risk factors for meticillin‐resistantStaphylococcus aureus(MRSA) carriage inMRSA‐exposed household pets
Authors: Cotter Caitlin J. , Ferradas Cusi , Ludwig Shanna , Dalton Kathryn , Larsen Jesper , Laucks Daniel , Iverson Sally Ann , Baron Patrick , Tolomeo Pam C. , Brazil Amy M. , Ferguson Jacqueline M. , Lautenbach Ebbing , Rankin Shelley C. , Morris Daniel O. , Davis Meghan F. 
Published: November 2022

AbstractBackgroundHousehold pets can carry meticillin‐resistantStaphylococcus aureus(MRSA) introduced to the home by their human companions. Specific factors promoting pet carriage of this pathogen have not been fully elucidated.ObjectiveThis study evaluated MRSA cultured from pets and the home environment in households where a human infected with MRSA had been identified, and aimed to determine potential risk factors for pet MRSA carriage.Materials and MethodsHumans diagnosed with community‐associated MRSA (CA‐MRSA) skin or soft‐tissue infection (SSTI) in the mid‐Atlantic United States were identified. One hundred forty‐two dogs and cats from 57 affected households were identified of which 134 (94.4%) pets and the household environment were sampled for bacterial culture, PCR confirmation andspa‐typing for MRSA strain determination. Samples were obtained 3 months later from 86 pets.ResultsAt baseline, 12 (9.0%) pets carried MRSA. Potential risk factors associated with carriage included pet bed (environmental) MRSA contamination, flea infestation and prior antimicrobial use in the pet. Pets tended to carry human‐adapted MRSA strains andspa‐types of MRSA isolates cultured from pets were concordant with strains cultured from the home environment in seven of eight homes (87.5%) at baseline.Conclusions and Clinical RelevanceResults may inform risk‐based veterinary clinical recommendations and provide evidence for selective pet testing as a possible alternative to early removal of pets from the homes of humans infected with MRSA. MRSA contamination of the home environment is likely an important risk factor for pet MRSA carriage, and household interventions should be considered to reduce risk of MRSA carriage in exposed pets.
Coke Drum Keyhole Optimization With Alloy Weld Overlay
Authors: Fernando John , Falo Enzo , Kwok Henry , Iverson Millar , Wong Leanne , Yuen Simon , Chan Luke 
Published: November 2022

Abstract
Coke drums are subjected to severe cyclic thermal and structural loading, and have therefore become canonical examples of thermo-mechanical fatigue failure. One of the most common locations of fatigue failure is at the skirt-to-shell attachment weld. To increase the fatigue life of the attachment weld, vertical slots and keyholes are often machined in a circumferential pattern near the top of the skirt to increase local flexibility near the weld. While this methodology provides a cost-effective means to improve the fatigue life of the attachment weld, stress concentrations that form at the keyholes result in crack initiation and propagation. As such, frequent repairs are necessary to prevent crack growth at the keyhole locations. In the present investigation, a new keyhole design consisting of N06625 overlay at the keyhole locations as a means of delaying crack initiation has been studied using FEA simulations. To further optimize the new design, a sensitivity study involving keyholes with and without fillets was also performed to determine the effect of fillet size on fatigue life. The results presented herein indicate that increasing the keyhole fillet radii mitigates the effect of stress concentrations on the corners of the keyholes, which delays crack initiation. Furthermore, it has been demonstrated that adding N06625 overlay at the keyhole protects the base metal from excessive plastic strain. In particular, the proposed design has been shown to improve the fatigue life of the keyhole by at least an order of magnitude when compared to analogous keyhole designs with no overlay, which has the potential to improve the overall cost-effectiveness of keyhole implementation by a significant margin.
Evaluation for Residual Lifetime and Remaining Axial Tension to Loosening Failure on Bolted Joints Used in Long-Life Machine and Plant Equipment
Authors: Hareyama Soichi , Manabe Kenichi , Kobayashi Satoshi 
Published: November 2022

Abstract
The bolted joints used in mechanical structures loosen owing to, for example, a decrease in the initial axial tension (clamping force) and repeated external forces in the direction perpendicular to the axis. A Junker-type loosening test used to evaluate the performance of various types of locking devices in a short period of time has been established. In such a test, it is possible to compare the loosening performance characteristics of various bolted joints and locking devices. However, it has not been possible to absolutely determine the period of time that they can maintain their initial locking performance. This paper presents a method of estimating the absolute locking performance of bolted joints. The absolute evaluation of self-loosening is indispensable for the prediction of the lifetime of locking devices (parts and methods) in actual machines. From the results of our experimental study, we found a strong linear correlation on logarithmic coordinates between the decreases in axial tension (measured/initial axial tension) and the number of operations (or working time or mileage) since the last tightening. The loosening phenomenon of bolted joints can be observed as the tendency of the initial or residual axial tension to decrease. By utilizing the regression formula at logarithmic coordinates, we show an estimation method for residual axial tension to answer various questions such as “How much of the axial tension remains after tens of thousands of hours (operations)?” Therefore, it is possible to determine to what extent can the bolted joints of long-life machines and plant equipment in medium-to-long-term use be considered to loosening failure. Finally, we describe the judgement criterion for loosening. We examine evaluation criteria such as “Is the residual axial tension sufficient for the prevention of loosening failure?” The limit surface pressure is examined as the upper limit axial tension. As the lower limit axial tension, the allowable value of the external transverse force is examined.
New ASME Standard on Plant Systems Design
Authors: Hill Ralph , deLamare Michael , Harper Jared , Shook Jeremy 
Published: November 2022

Abstract
This paper describes the purpose and objectives of the ASME Plant Systems Design Standard (PSD-1) that is currently under development. A general overview of the content of the standard and a more detailed overview of the plant systems design process are provided.
The plant systems design development processes that are the focus of PSD-1 are intended as enhancements to current industry design practices with the objective of reducing design errors or omissions that can increase the cost of design, construction, operation, maintenance, decontamination, decommissioning, and disposal.
PSD-1 integrates a system engineering approach with current industry design processes. Implementing systems engineering processes, methods and tools will provide greater assurance that customer and other stakeholder requirements are addressed at the correct stage of design in an efficient manner. This approach will reduce design errors, avoid re-designs and re-works, and provide a more cost-effective design.
Testing for the Effects of Pressurized Hydrogen on Polymeric Elastomers
Authors: Ellis Jeff , Whitman Jessica , Zoller Laura 
Published: November 2022

Abstract
This work demonstrated an experimental testing process to quantitatively test for the effects of pressurized hydrogen on polymeric materials. It was shown that some o-ring materials are susceptible to deleterious property changes. A high-pressure hydrogen testing system with a window was fabricated and was used to soak elastomeric o-rings in hydrogen at temperatures from 22 to 40°C and 13.8 to 16.5 MPa for up to 96 hours. Next, the o-rings were observed through the window during the depressurization. Finally, the o-rings were characterized before and after hydrogen exposure for hardness, weight, tensile strength, and ultimate elongation. The data showed the following four quantitative trends 1) durometer decreased up to 14%, 2) weight was mostly unchanged, 3) tensile strength decreased up to 35%, 4) ultimate elongation decreased up to 55%.
A Fragment Impact Simulation for a Turbomolecular Vacuum Pump Blade Failure Event
Authors: Valdiviez Robert 
Published: November 2022

Abstract
This simulation effort is of a high-speed fragment impacting a housing wall in order to predict if the housing material and configuration are capable of stopping the fragment. This application involves a turbine style high-vacuum pump, known as a turbomolecular pump, that produces a high-vacuum atmosphere within a given volume that it is connected to. The basic design of the turbomolecular pump has a motor turned rotor with several turbine blades attached to it, and that spins at high rotational speeds, up to 60,000 revolutions per minute. The turbine blades are configured on the rotor to impact and move gas molecules axially through the pump and eventually to an exhaust location. In order to achieve a high pumping speed, the rotor needs to turn at very high rotational speeds. A turbine blade failure, therefore, can throw high-speed fragments against the turbine pump housing, and potentially breach the housing. The safety design objective is to keep all debris captured within the turbine pump housing as the pump rotor spins down from the blade failure event. The dynamic properties of the materials of construction are applied, along with the pertinent initial and boundary conditions to create a simulation model that predicts the results of this high-speed fragment impact case.
An Improved Fixture to Quantify Corrosion in Bolted Flanged Gasketed Joints Subjected to Service Conditions
Authors: Hakimian Soroosh , Hof Lucas A. , Bouzid Hakim A. 
Published: November 2022

Abstract
This study concentrates on the corrosion behavior of bolted flanged gasketed joint systems. A novel fixture is proposed to quantify the corrosion between gaskets and flanges under services conditions. According to the literature, due to the presence of crevices and potential differences between gaskets and flanges, corrosion widely occurs in such joints. Crevice corrosion and galvanic corrosion can create paths to leakage of the pressurized fluid and may cause catastrophic failure. Corrosion in bolted gasketed joints was investigated previously; however, the effects of the operating conditions were not reported. Operating conditions include fluid flow, pressure, pH, conductivity, temperature, and gasket contact pressure. The first step of this research study is to introduce a new experimental setup to examine the corrosion behavior of bolted flanged gasketed joints. The developed setup is a fixture that consists of a pressurized bolted gasketed joint that enables real-time monitoring and recording of the corrosion parameters under the influence of service conditions. In the second step, potentiodynamic polarization test is carried out (according to ASTM G5) to measure the corrosion rate and obtain more details on the corrosion behavior of a pair flange and gasket materials. These tests are conducted using the novel designed setup that reproduce the behavior of industrial bolted flanged gasketed joint systems. It consists of a working electrode (flange material), a reference electrode (Ag/AgCl), and an auxiliary electrode (a stainless-steel rod). Three types of graphite gaskets are considered for electrochemical tests. The 0.6 M NaCl solution is used for the corrosion tests. After each test, the corroded surfaces of the specimens are examined via confocal laser microscopy to visualize the morphology of the damaged zones on the surface and localize corrosion, respectively.
Washers: Are They as Good as We Think?
Authors: Hamilton Scott , Meigs Dan 
Published: November 2022

Abstract
Many bolting professionals in the heavy industrial industry rely on the belief that “Washers play an essential role in generating and sustaining integrity in bolted assemblies.” [1] It is believed that washers improve the reliability of bolted joints by providing a consistent K-Factor by introducing a flat even plane on which the nut can rotate.
During practical training we noticed that using washers resulted in greater difference in bolt load between studs than experienced without washers. That experience led the authors to hypothesize that washers do not improve the accuracy and repeatability of bolted flange joints. This paper reports the findings of a study conducted to test this hypothesis.
The study recorded the variance in measured K-Factor when tightening nuts against various flange surfaces with and without washers and determined that, when properly lubricated, the performance of studs against various flange surfaces did not vary greatly from the performance of studs against washers. Additionally, in some cases washers introduced a source of variance in bolt load.
In addition to their perceived benefit in generating and maintaining tension in the bolted flange joint, washers are understood to provide benefits including preventing damage to the flange surface, preventing galling of the flange surface, and preventing nut embedment. This study focused on the use of washers in generating the expected bolt load and did not assess those additional benefits of washer usage.
Investigation on Mechanical Properties of X80 Pipeline Girth Weld Welded by Semi-Automatic and Automatic Welding
Authors: Ren Wei , Shuai Jian 
Published: November 2022

Abstract
The traditional manual welding in pipeline construction is being gradually replaced by semi-automatic and automatic welding in China. Semi-automatic welding is especially applied to X80 pipeline girth weld welding widely. Compared with semi-automatic welding, automatic welding has features of more efficiency, better quality and higher reliability. As the strength of pipeline steel increasing and the length, diameter as well as wall thickness of pipeline enlarging, automatic welding becomes the main trend at the development of the pipeline welding technology in the foreseeable future. Grasping the mechanical properties of X80 pipeline girth weld is crucial to ensuring the safety of pipeline operation. In order to determine the mechanical properties of X80 pipeline girth weld welded by semi-automatic and automatic welding, the experimental specimens were extracted from X80 pipeline girth weld welded by semi-automatic and automatic welding respectively to carry out the uniaxial tensile tests, fracture toughness tests and Charpy impact tests. In the tensile tests, the ultimate tensile strength of X80 pipeline girth weld welded by automatic welding (GWA) was higher than that of X80 pipeline girth weld welded by semi-automatic welding (GWSA) and the former had smaller dispersions. The fracture toughness tests showed that the fracture toughness of GWA was higher than that of GWSA. The Charpy impact tests results revealed that the impact energy of GWA was higher than that of GWSA. From the overall point of view, the mechanical properties of GWA are better than that of GWSA. The automatic welding technique is recommended for the welding of X80 pipeline, which is vitally important to maintain the structural integrity of X80 pipeline.
Application of Small Punch Testing Methods for Thermal Ageing Assessment at Steam-Generators Materials From Decommissioned V1 NPP to LTO Support on VVER Type Units in Slovakia
Authors: Petzova Jana , Adamech Marek , Slnek David 
Published: November 2022

Abstract
The main degradation mechanism of NPP’s components is radiation damage, but these processes are situated only in the core region of the reactor pressure vessel (RPV). The main mechanical loading of all individual parts of NPP’s primary circuit are the influence of high pressure at elevated temperature till 300°C. These processes lead to the fatigue damage of structural materials, which is characterized as the thermal fatigue or thermal ageing. The decommissioning of two V1 units in Slovakia provides a great opportunity to preserve materials from equipment that was in conditions of real operation for decades (app. 28–29 campaigns). VUJE, in cooperation with other partners, prepared necessary steps to create a material archive and related database including all relevant information from the decommissioned units of WWER-440 reactors. The main goal is to evaluate the real influence of long-term operation (LTO) on the degradation of NPP parts, such as steam-generators (SGs).
The Small Punch Test (SPT) methods are mainly used for evaluation of materials actual state. By the SPT technique it is possible to evaluate the basic tensile properties as the ultimate tensile strength and the yield stress of the tested materials from a very small amount of obtained material. The paper deals with description of special sampling from steam generators of operating units in Slovakia and subsequent testing of samples taken by the SPT method. All these results were compared with reference testing on materials taken from decommissioned V1 NPP.
Creep Life Prediction Using Creep Tests and Omega Method: Practical Application to a 2.25Cr-1Mo Steel
Authors: Planques Pierre , Le Guellaut Anthony , Goti Raphaël , Viguier Bernard 
Published: November 2022

Abstract
In this research, creep tests were carried out on ex-service 2.25Cr-1Mo steel under conditions more severe than those of service. The specimens were tested in a temperature range of 585°C up to 650°C and in a stress range of 65 MPa up to 120 MPa, leading to strain rates values of the order of 10−5 h−1. Conventional creep rupture tests and stepped tests (isothermal and multiple load levels) were conducted. The results of these tests are presented in terms of rupture time and the Omega method parameters Ω, and ε˙0.
The implementation of the Omega method, testing methods and the test conditions are then discussed together with the values of the parameters Ω and ε˙0 obtained. Those values were compared to the corresponding values from API579-1 data base [1] and the adjustment factors ΔcdΩ and ΔsrΩ. Lifetime prediction of the Omega method and the importance to identify the material scatter parameters for a given metallurgical condition are discussed.
An Update of the Assessment Methodology for Civil Ageing Management: Damage Development in Concrete Structures of a Reactor due to Ageing Mechanisms
Authors: Hasa Ledia , de Haan - de Wilde F. H. E. 
Published: November 2022

Abstract
For many nuclear power plants worldwide the operation period will be extended to 60 or 80 years. As the operation period increases, the importance of knowledge of ageing mechanisms increases. In the framework of LTO there is limited knowledge about ageing and structural integrity of concrete structures. Recent developments have shown that ageing of civil structures receive more attention internationally. In order to increase the knowledge in the field of civil structures, this paper focusses on investigation of ageing of civil structures and determining an ageing management strategy. Knowledge of the ageing mechanisms of civil structures and especially concrete, will lead to improvement of ageing management and assessment methods of concrete.
The presented work is part of ongoing research. In the past several steps have been made. Gathering of international information on civil structures ageing issues and management thereof (see PVP2019-93029 [3]), testing of a proposed assessment methodology by application to a nuclear reactor and comparison with another PWR with a steel containment (see PVP2020-21838 [4]) and creating a list of plant specific AMPs dealing with the relevant mechanisms at the various locations in a practical manner (see PVP2021-61499 [5]). The result was a general list with possible relevant locations and what type of measures could be taken. The current steps in the research focus on material behavior of structural concrete and practical assessment in finite element modelling techniques.
In a this step, the concrete material and behavior will be investigated and explained. The characteristic properties of the concrete will be summarized and the degradation mechanisms will be identified. The assessment criteria for concrete finite element modelling are defined.
The overall goal of the project is to obtain more knowledge on ageing management of civil structures and especially concrete. In the current research steps the aim is to create a predictive tool with the FE modelling technique for the damage quantification in concrete due to its ageing mechanism.
The results of this ongoing work are presented in this report. The characteristic properties, degradation mechanisms including modelling options are identified together with an investigation on the assessment criteria for concrete finite element modelling. The behavior of structural concrete will be explained.
The conclusion represents input parameters, modelling options and assessment criteria for finite element modelling of concrete.
In the future steps a practical assessment in finite modelling techniques will be introduced in order to take into consideration the degradation of the concrete. The material properties will be analyzed and adapted in an FE Model.