bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Non-Hertzian Contact Models on Derailment Simulation
Authors: Guan Qinghua , Liu Binbin , Bruni Stefano 
Published: August 2020

Abstract
The derailment of trains is a complex phenomenon that requires an elaborate contact model in simulation to better understand its mechanism. The CONTACT program is a well-known reference for wheel-rail contact modeling due to its high accuracy. However, its low computational efficiency restricts its applications especially in the context of a multi-body simulation. Therefore, a high computational efficient, simplified and approximate non-Hertzian contact is preferred in derailment simulation. The aim of this research is to verify the efficiency of a recently developed non-Hertzian wheel-rail contact model in derailment simulation, which is a combination of the Kik-Piotrowski model and the KBTNH that is a fast creep force solver for non-Hertzian contacts. To assess the performance of the non-Hertzian model in derailment simulation, the derailment coefficient for steady-state and quasi-steady conditions, the wheel/rail contact forces during flange contact, and the dynamics behaviors of the wheelset prior to the derailment are compared with the state of the art contact methods representing different levels of modeling complexity, accuracy and efficiency, namely the classical approach (Hertz theory+FASTSIM algorithm) and the ‘exact’ solver CONTACT.
Thermal Buckling in CWR Tracks: Critical Aspects of Experimental Techniques for Lateral Track Resistance Evaluation
Authors: Pucillo Giovanni Pio 
Published: August 2020

Abstract
After the introduction of continuous welded rail, thermal track buckling has been recognized to be one of the unsolved problem caused by this technological railroad improvement. In general, both weak ballast strength in the lateral direction and large alignment defects are the principal causes of such phenomenon.
In the UIC 720 Leaflet, which is the reference standard for the realization and maintenance of continuous welded rail tracks, two safety criteria against thermal track buckling are described: one is based on the maximum (ΔTmax) and minimum (ΔTmin) buckling temperatures, the other only on the minimum buckling temperature.
In the literature, it is found that a correlation exists between ΔTmax and the maximum (or peak, FP) lateral resistance value of the tie-ballast system, and, analogously, between ΔTmin and the minimum (or limit, FL) lateral resistance. For this reason, railway technicians had to paid special attention in the assessment of FP and FL.
Because FP concerns lateral displacements equal to 5÷10 mm, and FL occurs for lateral displacements greater than 80÷100 mm, some researchers have proposed to measure FP with a quasi-non-destructive experimental technique, the Single Tie Push Test (STPT), and, successively, to evaluate FL as a function of FP by empirical formulas, in place of the experimental evaluation of the full lateral resistance curve of the tie-ballast system.
Based on these considerations, a concerning issue arises whether it is sufficient, and above all safe, to use the simpler, less destructive, and less expensive STPT technique, which requires that only one tie is detached from the rails, or if it is necessary to perform lateral resistance tests on track panels composed by 4 to 6 ties, as in the case of the Discrete Cut Panel Pull Test (DCPPT).
For this purpose, in this paper the experimental results obtained in situ in full scale conditions with the two testing techniques are reported, and the differences obtained by performing tests with one, two, and four ties are analyzed with the aim of ensuring a safe evaluation of the main input parameters required for buckling temperatures calculation.
It is found that the limit lateral resistance depends neither on the chosen experimental technique, nor on the compaction level of the ballast bed, whereas the peak lateral resistance appears to be dramatically altered if it is evaluated by mean of the STPT, with serious risks of an unsafe evaluation of the buckling temperatures.
Broken Rail Prediction With Machine Learning-Based Approach
Authors: Zhang Zhipeng , Zhou Kang , Liu Xiang 
Published: August 2020

Abstract
Broken rails are the most frequent cause of freight train derailments in the United States. According to the U.S. Federal Railroad Administration (FRA) railroad accident database, there are over 900 Class I railroad freight-train derailments caused by broken rails between 2000 and 2017. In 2017 alone, broken rail-caused freight train derailments cause $15.8 million track and rolling stock damage costs to Class I railroads. The prevention of broken rails is crucial for reducing the risk due to broken rail-caused derailments. Although there is fast-growing big data in the railroad industry, quite limited prior research has taken advantage of these data to disclose the relationship between real-world factors and broken rail occurrence. This article aims to predict the occurrence of broken rails via machine learning approach that simultaneously accounts for track files, traffic information, maintenance history, and prior defect information.
In the prediction of broken rails, a machine learning-based algorithm called extreme gradient boosting (XGBoost) is developed with various types of variables, including track characteristics (e.g. rail profile information, rail laid information), traffic-related information (e.g. gross tonnage recorded by time, number of passing cars), maintenance records (e.g. rail grinding and track ballast cleaning), and historical rail defect records. Area Under the Curve (AUC) is used as the evaluation metric to identify the prediction accuracy of developed machine learning model. The preliminary result shows that the AUC for one year of the XGBoost-based prediction model is 0.83, which is higher than two comparative models, logistic regression and random forests. Furthermore, the feature importance discloses that segment length, traffic tonnage, number of car passes, rail age, and the number of detected defects in the past six months have relatively greater importance for the prediction of broken rails. The prediction model and outcomes, along with future research in the relationship between broken rails and broken rail-caused derailment, can benefit railroad practical maintenance planning and capital planning.
Wheel-Rail Contact Modelling for Locomotive Traction Control System Studies
Authors: Spiryagin Maksym , Wu Qing , Bosomworth Chris , Cole Colin , Hayman Mark , Persson Ingemar 
Published: August 2020

Abstract
Recent locomotive traction studies have been extensively focused on the development of wheel-rail contact models for application inside multibody software products to compute results which can be further used in the prediction of track damage indexes. These models are quite sufficient, but they have a significant disadvantage of slow computational speed. In order to use the same locomotive models for traction studies, a new concept of the model was studied. The main difference from existing models is the developed normal task approach that provides a transition from non-Hertzian to Hertzian contact patches and this innovation was validated against the results obtained in a parallel computation test implemented inside of the wheel-rail coupling based on the Extended Contact library. The test was performed with a multibody locomotive model running on tangent track. The first implementation of the developed wheel rail-coupling has been tested in a parallel mode with the Extended Contact library on a full mechatronic model of a locomotive and the results compared against each other. Discussion on the further development is provided.
On the Interpretation and Scope of the V&V 20 Standard for Verification and Validation in Computational Fluid Dynamics and Heat Transfer
Authors: Eça L. , Dowding K. , Roache P. J. 
Published: August 2020

Abstract
The goal of this paper is to summarize and clarify the scope and interpretation of the validation procedure presented in the V&V20-2009 ASME Standard. In V&V20-2009, validation is an assessment of the model error, without regard to the assessment satisfying validation requirements. Therefore, validation is not considered as a pass/fail exercise. The purpose of the validation procedure is the estimation of the accuracy of a mathematical model for specified validation variables (also known as quantities of interest, system responses or figures of merit) at a specified validation point for cases in which the conditions of the actual experiment are simulated. The proposed procedure can be applied to variables defined by a scalar.
For the sake of clarity, the paper reiterates the development and assumptions behind the V&V20-2009 procedure that requires the knowledge of the experimental values D and simulation values S at the set point and an estimate of the experimental, numerical and parameter uncertainties. The difference E between S and D is the centre of the interval that should contain the model error (with a certain degree of confidence) and the width of the interval is obtained from the validation uncertainty that is a consequence of the combination of the experimental, numerical and parameter uncertainties.
The paper presents the alternatives to address parameter uncertainty and expands upon the interpretation of the final result. The paper also includes two examples demonstrating the application of the V&V20-2009 validation procedure including one problem from V&V10.1-2012 on solid mechanics.
Ageism in the Fitness and Health Industry: A Review of the Literature
Authors: Jin Bora , Harvey Idethia Shevon 
Published: August 2020

This review aims to understand how age-related stereotypes against older adults’ physical capabilities influence their ability to engage in regular physical activity. The authors wanted to know how people construe ageism in the fitness and health arena, how ageism manifests in this field, and how ageism influences older adults’ learning and practicing physical activity. Data was extracted using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Twenty-two empirical studies met the selection criteria. The findings revealed that the attributes of ageism fell into either self-imposed or other-directed ageism categories and manifested as implicit or explicit ageism. The study also identified the following four themes: (a) perceptions of aging and exercise, (b) exercise motivation, (c) opportunities for older adults, and (d) ambiguous positionality as older exercisers. The research provides evidence for the existence of ageism against older exercisers. Further research considering the implication of ageism within the exercising industry is necessary.
Comparative efficacy of different exercise interventions in chronic non-specific low back pain: protocol of a systematic review and network meta-analysis
Authors: Anheyer Dennis , Klose Petra , Koch Anna Katharina , Haller Heidemarie , Dobos Gustav , Cramer Holger 
Published: August 2020

IntroductionChronic non-specific low back pain is a major public health problem. Evidence supports the effectiveness of exercise as an intervention. Due to a paucity of direct comparisons of different exercise categories, medical guidelines were unable to make specific recommendations regarding the type of exercise working best in improving chronic low back pain. This network meta-analysis (NMA) of randomised controlled trials aims to investigate the comparative efficacy of different exercise interventions in patients with chronic non-specific low back pain.Methods and analysisMEDLINE, Scopus, Cochrane Central Register of Controlled Trials, Physiotherapy Evidence Database, SPORTDiscus, Clinicaltrials.gov and the WHO International Clinical Trials Registry Platform search portal were searched on November 2019 and without language restrictions. The search will be updated after data analysis. Studies on adults with non-specific low back pain of at least 12 weeks duration comparing exercise to either no specific intervention (ie, no treatment, wait-list or usual care at the treating physician’s discretion) and/or functionally inert interventions (ie, sham or attention control interventions) will be eligible. Pain intensity and back-specific disability are defined as primary outcomes. Secondary outcomes will include health-related physical and mental quality of life, work disability, frequency of analgesic use and adverse events. All outcomes will be analysed short-term, intermediate-term and long-term. Data will be extracted independently by two review authors. Risk of bias will be assessed using the recommendations by the Cochrane Back and Neck Group and be based on an adaptation of the Cochrane Risk of Bias tool.Ethics and disseminationThis NMA will be reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses_NMA checklist. The results will be presented in peer-reviewed journals, implemented in existing national and international guidelines and will be presented to health care providers and decision makers. The planned completion date of the study is 1 July 2021.PROSPERO registration numberCRD42020151472.
Association between family functions and antenatal depression symptoms: a cross-sectional study among pregnant women in urban communities of Hengyang city, China
Authors: Zheng Baohua , Yu Yunhan , Zhu Xidi , Hu Zhao , Zhou Wensu , Yin Shilin , Xu Huilan 
Published: August 2020

ObjectiveTo explore the prevalence of depressive symptoms among women in late pregnancy, and assess mediating effect of self-efficacy in the association between family functions and the antenatal depressive symptoms.DesignCommunity-based, cross-sectional study was conducted among women during the third trimester of pregnancy.SettingThis study was conducted among pregnant women registered at community health service centres of urban Hengyang City, China from July to October 2019.Participants813 people were selected from 14 communities by multi-staged cluster random sampling method.Main outcome measuresThe Family Adaptation Partnership Growth Affection and Resolve Index, the General Self-efficacy Scale and Patient Health Questionnaire were used to access family functions, self-efficacy and antenatal depression symptoms, respectively.ResultsIn this study, 9.2% pregnant women reported the symptoms of antenatal depression (95 CI% 7.2% to 11.2%). After adjustment, the results showed that severe family dysfunction (adjusted OR, AOR 3.67; 95% CI 1.88 to 7.14) and low level of self-efficacy (AOR 3.16; 95% CI 1.37 to 7.27) were associated with antenatal depressive symptoms (p<0.05). Furthermore, self-efficacy level partially mediated the association between family functions and antenatal depressive symptoms(β=−0.05, 95% CI −0.07 to −0.03, p<0.05) and the mediating effect accounted for 17.09% of the total effect.ConclusionsThis study reported 9.2% positive rates of antenatal depression symptoms among women in the third trimester of pregnancy in Hengyang city, China. The mediating effect of self-efficacy on the association between family functions and antenatal depression symptoms among women in the third trimester of pregnancy was found in this study, which provide a theoretical basis to maternal and child health personnel to identify high-risk pregnant women and take targeted intervention for them.
$$\varepsilon '/\varepsilon $$ in the Standard Model at the Dawn of the 2020s
Authors: Aebischer Jason , Bobeth Christoph , Buras Andrzej J. 
Published: August 2020

AbstractWe reanalyse the ratio $$\varepsilon '/\varepsilon $$ε′/ε in the Standard Model (SM) using most recent hadronic matrix elements from the RBC-UKQCD collaboration in combination with most important NNLO QCD corrections to electroweak penguin contributions and the isospin-breaking corrections. We illustrate the importance of the latter by using their latest estimate from chiral perturbation theory (ChPT) based on the octet approximation for lowest-lying mesons and a very recent estimate in the nonet scheme that takes into account the contribution of $$\eta _0$$η0. We find $$(\varepsilon '/\varepsilon )^{(8)}_\text {SM} = (17.4 \pm 6.1) \times 10^{-4}$$(ε′/ε)SM(8)=(17.4±6.1)×10-4 and $$(\varepsilon '/\varepsilon )^{(9)}_\text {SM} = (13.9 \pm 5.2) \times 10^{-4}$$(ε′/ε)SM(9)=(13.9±5.2)×10-4, respectively. Despite a very good agreement with the measured value $$(\varepsilon '/\varepsilon )_\text {exp} = (16.6 \pm 2.3) \times 10^{-4}$$(ε′/ε)exp=(16.6±2.3)×10-4, the large error in $$(\varepsilon '/\varepsilon )_\text {SM}$$(ε′/ε)SM still leaves room for significant new physics (BSM) contributions to this ratio. We update the 2018 master formula for $$(\varepsilon '/\varepsilon )_\text {BSM}$$(ε′/ε)BSM valid in any extension beyond the SM without additional light degrees of freedom. We provide new values of the penguin parameters $$B_6^{(1/2)}(\mu )$$B6(1/2)(μ) and $$B_8^{(3/2)}(\mu )$$B8(3/2)(μ) at the $$\mu $$μ-scales used by the RBC-UKQCD collaboration and at lower scales $$\mathcal {O}(1\, \text {GeV})$$O(1GeV) used by ChPT and Dual QCD (DQCD). We present semi-analytic formulae for $$(\varepsilon '/\varepsilon )_\text {SM}$$(ε′/ε)SM in terms of these parameters and $$\hat{\Omega }_\text {eff}$$Ω^eff that summarizes isospin-breaking corrections to this ratio. We stress the importance of lattice calculations of the $$\mathcal {O}(\alpha _{\text {em}})$$O(αem) contributions to the hadronic matrix elements necessary for the removal of renormalization scheme dependence at $$\mathcal {O}(\alpha _{\text {em}})$$O(αem) in the present analyses of $$\varepsilon '/\varepsilon $$ε′/ε.
Apolipoprotein CIII Deficiency Protects Against Atherosclerosis in Knockout Rabbits
Authors: Yan Haizhao , Niimi Manabu , Matsuhisa Fumikazu , Zhou Huanjin , Kitajima Shuji , Chen Yajie , Wang Chuan , Yang Xiawen , Yao Jian , Yang Dongshan , Zhang Jifeng , Murakami Masami , Nakajima Katsuyuki , Wang Yao , Liu Enqi , Liang Jingyan , Chen Y. Eugene , Fan Jianglin 
Published: August 2020

Objective:
Apo (apolipoprotein) CIII mediates the metabolism of triglyceride (TG)-rich lipoproteins. High levels of plasma apoCIII are positively correlated with the plasma TG levels and increase the cardiovascular risk. However, whether apoCIII is directly involved in the development of atherosclerosis has not been fully elucidated.

Approach and Results:
To examine the possible roles of apoCIII in lipoprotein metabolism and atherosclerosis, we generated apoCIII KO (knockout) rabbits using ZFN (zinc finger nuclease) technique. On a normal standard diet, apoCIII KO rabbits exhibited significantly lower plasma levels of TG than those of WT (wild type) rabbits while total cholesterol and HDL (high-density lipoprotein) cholesterol levels were unchanged. Analysis of lipoproteins isolated by sequential ultracentrifugation revealed that reduced plasma TG levels in KO rabbits were accompanied by prominent reduction of VLDLs (very-low-density lipoproteins) and IDLs (intermediate-density lipoproteins). In addition, KO rabbits showed faster TG clearance rate after intravenous fat load than WT rabbits. On a cholesterol-rich diet, KO rabbits exhibited constantly and significantly lower levels of plasma total cholesterol and TG than WT rabbits, which was caused by a remarkable reduction of β-VLDLs—the major atherogenic lipoproteins. β-VLDLs of KO rabbits showed higher uptake by cultured hepatocytes and were cleared faster from the circulation than β-VLDLs isolated from WT rabbits. Both aortic and coronary atherosclerosis was significantly reduced in KO rabbits compared with WT rabbits.

Conclusions:
These results indicate that apoCIII deficiency facilitates TG-rich lipoprotein catabolism, and therapeutic inhibition of apoCIII expression may become a novel means not only for the treatment of hyperlipidemia but also for atherosclerosis.
Kidney Disease Biomarkers Improve Heart Failure Risk Prediction in the General Population
Authors: Nowak Christoph , Ärnlöv Johan 
Published: August 2020

Background:
The kidneys play an important role in heart failure (HF), but it is unclear if renal biomarkers improve HF risk prediction beyond established risk factors. We aimed to assess whether adding biomarkers of kidney disease to conventional risk factors improved 10-year risk prediction for incident HF in a contemporary community sample.

Methods:
We included 450 212 participants in the UK Biobank aged 39 to 70 years without HF who had been assessed in 2006 to 2010 with the urine albumin-to-creatinine ratio and estimated glomerular filtration rate (eGFR) based on serum creatinine and cystatin C. There were 1701 incident cases of HF during up to 10.3 years of follow-up (mean 8.2±0.7 years). We used the Atherosclerosis Risk in Communities study heart failure risk score excluding natriuretic peptides as the base model to which we added eGFR and urine albumin-to-creatinine ratio. Harrell’s C-statistic of ARIC-HF was 0.845 (95% CI, 0.831–0.859).

Results:
Each combination of added kidney measures (creat-eGFR, cysC-eGFR, and urine albumin-to-creatinine ratio) led to significant improvement in risk discrimination, calibration, and reclassification. The optimal pair of added kidney measures was cysC-eGFR and urine albumin-to-creatinine ratio (ΔC=0.019 [95% CI, 0.015–0.022]). Addition of cysC-eGFR made the largest contribution to reclassification improvement (continuous net reclassification improvement 0.323 [95% CI, 0.278–0.360]).

Conclusions:
In a large community sample, the addition of kidney disease markers to conventional risk factors improved prediction of 10-year HF risk. Our results support including kidney disease markers in the identification of persons at highest risk of HF and demonstrate a possible role of impaired kidney function in HF development in asymptomatic persons.
Novel Micro Crown Orbital Atherectomy for Severe Lesion Calcification
Authors: Redfors Björn , Sharma Samin K. , Saito Shigeru , Kini Annapoorna S. , Lee Arthur C. , Moses Jeffrey W. , Ali Ziad A. , Feldman Robert L. , Bhatheja Rohit , Stone Gregg W. 
Published: August 2020

Background:
Percutaneous coronary intervention of severely calcified lesions carries a high risk of adverse events despite the use of contemporary devices. The Classic Crown Orbital Atherectomy System (OAS) was safe and effective for severely calcified lesion preparation in the ORBIT II study (Evaluate the Safety and Efficacy of OAS in Treating Severely Calcified Coronary Lesions) but was not optimized for tight lesions. COAST (Coronary Orbital Atherectomy System Study) evaluated the safety and efficacy of calcified lesion preparation before stent implantation with the Diamondback 360 Micro Crown Coronary OAS, designed for use in tighter lesions.

Methods:
COAST was a prospective, multicenter, single-arm study that enrolled 100 patients with severely calcified de novo coronary lesions at 17 sites in the United States and Japan. The primary effectiveness end point was procedural success, defined as stent delivery with residual stenosis <50% without in-hospital major adverse cardiac events (MACE), and the primary safety end point was freedom from MACE (composite of cardiac death, myocardial infarction, or target vessel revascularization) at 30 days.

Results:

The OAS Micro Crown was inserted in all patients. A stent was delivered with a residual stenosis <50% in all except one patient (99.0%). Procedural success was achieved in 85 (85.0%) subjects versus 391 (88.9%) in ORBIT II (
P
=0.30), and freedom from MACE at 30 days was achieved in 85.0% versus 89.6% in ORBIT II (
P
=0.21). Freedom from MACE was 77.8% at 1 year.

Conclusions:
Prestent preparation of severely calcified lesions using the novel Micro Crown OAS resulted in similar rates of procedural success and freedom from MACE compared with the Classic Crown OAS.

Registration:

URL:
https://www.clinicaltrials.gov
. Unique identifier: NCT02132611.