bluuebunny/crossref_metadata_2025_split huggingface dataset:
Life Prediction of Modified Grad 91 Tube-Sheet Structures Under Creep-Fatigue Loading Condition
Authors: Islam Nazrul , Uddin Md Ala 
Published: October 2021

Abstract
This study deals with the creep-fatigue strength evaluation of a tube-sheet structure made of Mod. Grade 91 steel. Such a structure is one of the components of Japan Sodium Fast Reactor (JSFR) that suffers the most severe loadings in the reactor and one of the most difficult components to design because of its complex three-dimensional semispherical shape with an arrangement of numerous holes. A test model of this component was developed by Japan Atomic Energy Agency and test was subjected to 1873 cycles of severe thermal transient loading in which elevated temperature at 600 °C and 250 °C was flowed using sodium flow repeatedly and kept at the final temperature for 2 h and 1 h, respectively. In this study, 3D finite element model of the component is developed, and heat transfer and stress analysis of this structure were performed using the temperature-dependent Mod. Grade 91 material properties for 100 cycles. Creep-fatigue life of the component is initially evaluated using the stress redistribution locus and simple elastic follow up methods. The creep-fatigue results based on these elastic analyses are compared with the inelastic analysis based procedures that include nonlinear constitutive models e.g., bilinear and Chaboche model coupled with time hardening creep. The creep and fatigue damages using these methods are plotted in the Campbell diagram and predicted life cycles are compared to show the applicability of these methods for life prediction.
Flow-Induced Vibration Behaviour of a Rotated Square Tube Array Subjected to Cross-Flow
Authors: Darwish S. , Hadji A. , Pham H. P. , Mureithi N. , Ha C. H. 
Published: October 2021

Abstract
The present paper presents experimental tests investigating flow-induced vibration and possible fluidelastic instability (FEI) in a rotated square geometry tube array. The pitch spacing ratio of approximately P/D = 1.64 is somewhat larger than that found in typical array geometries. Experiments were conducted in water flow. The stability of a single flexible tube as well as multiple flexible tubes was investigated. The tubes were free to vibrate purely in the streamwise direction or the transverse direction relative to the upstream flow. A single flexible tube, in the otherwise rigid tube array, was found to undergo large amplitude vibrations (up to 40% D) in the transverse direction. Tube vibration response PSDs indicated the presence of two frequency components related to vorticity shedding in the array. This potential vorticity-induced-vibrations (VIV) and potential coupling between VIV and FEI is discussed in the paper. Test results for streamwise flow-induced vibrations are also presented. Results in water flow show a possible effect related to VIV at low velocity. At significantly high flow velocity, the tubes are found to fully restabilize. This restabilization after VIV locking has not been previously reported as an unlocking result. The present results suggest that flow-induced vibration of tubes in a rotated square array configuration is significantly more complex than in other geometries, particularly for the streamwise vibration case.
A Unified Constitutive Model for Diffusion Bonded Alloy 800H To Perform Full Inelastic Analysis of Components in High Temperature Nuclear Service
Authors: Mahajan Heramb P. , Hassan Tasnim 
Published: October 2021

Abstract
Implementing the generation IV nuclear reactor concept to nuclear service needed elevated temperature component analysis and design methodologies. These components experience elevated temperature loads such as creep, fatigue, creep-fatigue, and ratcheting. Traditional elastic, simplified inelastic, or elastic-perfectly plastic analysis and design methods per Section III, Division 5 fails to capture the detailed material behavior. Full inelastic analysis methods governed by the unified constitutive model (UCM) have shown promise in capturing the complicated material behavior at elevated temperatures. Current Section III, Division 5 design code do not provide guidelines for UCM based full inelastic analysis of Gen. IV components using finite element methods. Gap analysis of the current Section III, Division 5 design code indicated the need to develop unified constitutive models (UCMs) and their optimized parameter sets for performing full inelastic analysis. This paper presents a UCM with two and four nonlinear kinematic hardening rules for diffusion bonded (DB) Alloy 800H. Experiments on DB Alloy 800H are performed for developing and validating a UCM. The developed UCM captures the critical fatigue, creep, and creep-fatigue response features such as hysteresis loop, stress relaxation, rate effects, and cyclic hardening demonstrated by DB Alloy 800H experiments performed. Description of the UCM model developed and its optimized parameters for DB Alloy 800H and cor-responding simulations are presented. Future works to further develop the UCM are discussed.
Flow-Induced Vibration in a Single Row of Cylinders With p/D = 1.26
Authors: Neumeister Roberta F. , Petry Adriane P. , Möller Sergio V. 
Published: October 2021

Abstract
Crossflow over a row of cylinders with a close space ratio presents an asymmetric configuration with large and narrow wakes behind the cylinders. The wake interaction can impact the vibration response of the cylinders. In tube banks, the impact results in damages to the equipment. The present experimental study aims to analyze the influence of close space observed in a single row of cylinders on the flow-induced vibration. The study compares a single row with fixed cylinders and a single row with one cylinder free to vibrate. The cylinder free to vibrate is tested in four configurations. The study was conducted with an aerodynamic channel with a cross-section of 0.193 × 0.146 m and smooth cylinders with a diameter of 25.1 mm, space ratio is 1.26. The measurements are executed with hot-wire anemometry and accelerometers, for the cases with one cylinder free to vibrate and with hot-wire anemometry and microphones for the case with all fixed cylinders. The Reynolds number ranges between 1.0 × 104 and 4.5 × 104, obtained with the reference flow velocity, measured with a Pitot tube, and the cylinder diameter. The comparison between the wake response for single row fixed and single row and free to vibrate are executed using Fourier transform and Wavelet Transform. The comparison of the results with the models presented in the literature to predict the elastic instability of the fluid in a single row of cylinders is performed.
Development and Testing of an Active Trailing Edge Morphing Demonstrator for a Rotary Wing
Authors: Zahoor Yasir , Sodja Jurij , De Breuker Roeland , Voskuijl Mark 
Published: October 2021

Abstract
This paper discusses the development and whirl tower testing of an active translation induced camber morphing system for rotorcraft. The system deploys the morphing flap based on the amplitude and type of the input signal. As a case study, a demonstrator is developed and tested primarily under the centrifugal force generated by a whirl tower setup. The actuation system consists of amplified piezoelectric actuators, while the morphing skin is made out of carbon fiber prepreg composite material. The response of the morphing skin and the actuators is measured and compared to the numerical studies used to design the morphing demonstrator. Results indicate that the response of the active system, including the actuators and the flexible skin, matches well to those predicted during the numerical studies. The outcome of these studies shows that the system has the potential to be used for the primary control of the rotorcraft if operated at 1/revolution or for mitigating noise and vibration if operated at 2/revolution or higher frequencies. Subsequently, the concept can be integrated into a Mach-scaled rotor blade which can be tested under both aerodynamic and centrifugal loads to further assess its performance.
Additively Manufactured Force Sensors Based on Shape Memory Alloys
Authors: Heynen Alina , Roj Robin , Hoffmann Fabian , Krieg Romina , Theiß Ralf , Dültgen Peter 
Published: October 2021

Abstract
In view of additive manufacturing and customized solutions, this paper describes the development of force sensors by combining DLP-printed components with shape memory alloys. The focus is on material investigations followed by FEM analysis for the development of topology-optimized carriers. By integrating shape memory wires, the sensor effect can be exploited. On the basis of two structures, the implementation is tested in practice. Two different materials are used to check the reproducibility of the results. Both materials are synthetic resins that cure under UV light. Through the practical tests, the targetperformance comparison shows the feasibility of the experiments and thus the possibility of using the developed sensors for motion monitoring. With the fusion of 3D printing, topology optimization and shape memory technology, the advantages of weight reduction, durability and the realization of individual solutions are combined.
Design of Bistable Laminates With Low Aspect Ratio
Authors: Boddapati Karthik , Arrieta Andres F. 
Published: October 2021

Abstract
Bistable composite laminates have been widely studied for applications in morphing structures due to their ability to exhibit different shapes and distinct degrees of stiffness about each stable state. Laminates with low aspect ratios (Length/Width) suffer from decreased bending stiffness and easily lose bistability. The present work addresses this challenge by introducing parallel slits along the width of the laminate, thereby relieving the deformation and enabling natural curving of the laminates. We demonstrated this by developing a numerical model of a two-section bistable composite laminate with clamped boundary condition. The design of the slits is chosen by conducting stress analysis on the laminate and using the Tsai-Wu failure criterion to assess failure at the critical locations. Finally, a parametric study is conducted on the laminate with slits to determine the maximum width that preserves bistability.
Modeling of Piezoelectric Vibration Energy Harvesting From Low-Frequency Using Frequency Up-Conversion
Authors: Atmeh Mohammad , Ibrahim Alwathiqbellah 
Published: October 2021

Abstract
Energy harvesting becomes an effective method for self-powering systems in wireless applications for improved observation and measurements. However, traditional scavenging techniques cannot generate enough energy for proper operation under low-frequency ambient vibration. We present a frequency up-converter vibration energy harvester from low-frequency external vibrations. The harvester converts low-frequency vibrations to high-frequency self-oscillations through a mechanical frequency up-converter using magnetic coupling, thus providing more efficient energy conversion at low frequencies. The harvester consists of two cantilever beams with tip magnets facing each other at the same polarity. The low-frequency beam is made of polymer, while the high-frequency beam is made of Aluminum. The high-frequency beam is a bimorph fully covered with piezoelectric layers. A lumped parameter of two degree of freedom model is presented to simulate the dynamic behavior and the generated voltage signal. The static response of the resonators shows a threshold distance of 15mm between the two magnets where the system has monostable oscillates above the threshold and bistable oscillations below the threshold. Furthermore, the dynamic behavior for the resonators is investigated at monostable, threshold, and bistable regions for different excitation levels. The harvester’s output voltage at different resistance values is extracted from the model. frequency up-converting can effectively scavenge energy from low-frequency external vibrations by mechanically up-converting the ambient vibration frequency.
Modeling of Triboelectric Vibration Energy Harvester Under Rotational Magnetic Excitation
Authors: Hassan Mostafa , Baker Katy , Ibrahim Alwathiqbellah 
Published: October 2021

Abstract
A triboelectric vibration energy harvester under rotational magnetic excitation for wind energy harvesting applications is developed. The triboelectric beam generates electricity using the magnetic impact-induced vibration. The triboelectric energy harvester consists of a clamped-clamped (CC) beam embedded in an outer case. The lower side of the CC-beam acts as an upper electrode that will undergo a contact-separation motion with another lower electrode with a bonded Polydimethylsiloxane (PDMS) insulator. A permanent magnet will be attached to the CC-beam’s upper side and will face another magnet attached to a rotation rigid shaft blade at the same polarity. While the fan rotates, a repulsive magnetic force will be created between the two magnets that will excite the CC-beam, lead to the contact-separation motion, and generation of electricity. A single degree of freedom model is presented and simulated to extract the dynamic behavior and the generated electrical signal. The relationship between the output voltage and excitation rotational frequency is analyzed. The relationship between the output voltage and the distance between magnets and its effect on the bandwidth is also discussed. The effect of the surface charge density on the generated output voltage signal is examined. The rotational wind triboelectric energy harvester can effectively scavenge wind energy.
Volcanic origin of the mercury anomalies at the Cretaceous-Paleogene transition of Bidart, France
Authors: Font Eric , Chen Jiubin , Regelous Marcel , Regelous Anette , Adatte Thierry 
Published: October 2021

Abstract
The timing and mechanisms of the climatic and environmental perturbations induced by the emplacement of the Deccan Traps large igneous province (India) and their contribution to the Cretaceous-Paleogene (K-Pg) mass extinction are still debated. In many marine sediment archives, mercury (Hg) enrichments straddling the K-Pg boundary have been interpreted as the signature of Deccan Traps volcanism, but Hg may also have been derived from the Chicxulub (Mexico) impact. We investigated the Hg isotope composition, as well as the behavior of iridium (Ir) and other trace elements, in K-Pg sediments from the Bidart section in southwest France. Above the K-Pg boundary, Ir content gradually decreases to background values in the Danian carbonates, which is interpreted to indicate the erosion and redistribution of Ir-rich fallouts. No significant enrichment in Ir and W, or Zn and Cu, is observed just below the K-Pg boundary, excluding the hypothesis of downward remobilization of Hg from the boundary clay layer. Positive Δ199Hg and slightly negative values in the upper Maastrichtian and lower part of the early Danian are consistent with the signature of sediments supplied by atmospheric Hg2+ deposition and volcanic emissions. Up section, large shifts to strongly negative mass-dependent fractionation values (δ202Hg) result from the remobilization of Hg formerly sourced by the impactor or by a mixture of different sources including biomass burning, volcanic eruption, and asteroid impact, requiring further investigation. Our results provide additional support for the interpretation that the largest eruptions of the Deccan Traps began just before, and encompassed, the K-Pg boundary and therefore may have contributed to the K-Pg mass extinction.
Relationship between miR-338-3p and Clinicopathological Parameters, Prognosis, and STAT3 mRNA Expression in Nasopharyngeal Carcinoma
Authors: Wang Youyou , Ren Huijun , Pan Zhaohu , Liu Ben , Lin Fan 
Published: October 2021

Objective. To investigate the expression of miR-338-3p in nasopharyngeal carcinoma (NPC) and its relationship with STAT3 mRNA expression as well as their relationship with clinical pathological parameters and prognosis of patients. Methods. From September 2016 to September 2018, 71 patients with NPC were selected as the NPC group, and 71 samples of NPC tissues were collected during the operation. A total of 23 patients who underwent biopsy due to chronic nasopharyngitis were selected as the control group and 23 nasopharyngeal mucosal tissues were collected. The expressions of miR-338-3p and STAT3 mRNA in nasopharyngeal tissue of two groups were detected by real-time quantitative PCR, and the relationship between the two was analyzed. To collect clinical data of NPC patients and analyze the relationship between the expressions of miR-338-3p and STAT3 in NPC tissues and clinical pathological parameters of the patients, we followed up the patients with nasopharyngeal carcinoma for three years to observe the relationship between miR-338-3p, STAT3, and the prognosis of the patients. Results. The relative expression levels of miR-338-3p in nasopharyngeal tissues of the NPC group and the control group were 0.39 ± 0.05 and 1.01 ± 0.09, respectively (

P

< 0.05). The relative expression levels of STAT3 mRNA in nasopharyngeal tissues of the NPC group and the control group were 3.82 ± 0.21 and 1.04 ± 0.11, respectively (

P

> 0.05). miR-338-3p was negatively correlated with the relative expression of STAT3 mRNA in nasopharyngeal carcinoma (r = 0.038,

P

> 0.05). The expression of miR-338-3p was related to the age of the patient, clinical TNM stage, T stage, and distant metastasis (all

P

< 0.05). STAT3 expression was correlated with clinical TNM stage, T stage, and distant metastasis in our patient (

P

< 0.05). The expressions of miR-338-3p and STAT3 in nasopharyngeal carcinoma tissues from different gender, histological type, N stage, M stage, and degree of differentiation showed no statistical differences (

P

> 0.05). The survival rate of the group with low miR-338-3p expression was significantly lower than that of the group with high miR-338-3p expression (

P

> 0.05). The survival rate of patients with the high STAT3 expression group was significantly lower than that of patients with the low STAT3 expression group (

P

> 0.05). Conclusion. There is a negative correlation between the low expression of miR-338-3p and the high expression of STAT3 in NPC, which are all related to the TNM stage, T stage, and prognosis of the patient.
Association of Cardiology Billing Amounts With Health Care Utilization and Clinical Outcomes in Patients With Atrial Fibrillation
Authors: Bhatia R. Sacha , Chu Cherry , Kaoutskaia Anna , Ko Dennis T. , Shojania Kaveh G. , Dorian Paul , Yu Bing , Shurrab Mohammed , Fang Jiming , Ross Heather , Austin Peter C. , Bouck Zachary , Goodman Shaun G. , Crystal Eugene 
Published: October 2021

Background
The relationship between health care utilization and outcomes in patients with atrial fibrillation is unknown. The objective of this study was to investigate whether cardiologists’ billing amounts in a fee‐for‐service environment are associated with better patient‐level clinical outcomes.

Methods and Results
A retrospective cohort study was conducted using administrative claims data of cardiologists in Ontario, Canada between April 1, 2011 and March 31, 2016. The cardiologists were stratified into quintiles based on their median billing patterns per patient over the observation period. The primary outcomes were patient‐level receipt of repeat visits, cardiac diagnostic tests, and medications ≤1 year of index date. The secondary clinical outcomes were death, emergency department visits, and all‐cause hospitalization 1‐year post‐index visit. The patient cohort comprised 182 572 patients with atrial fibrillation (median age 74 years, 58% male) from 467 cardiologists. Patients with atrial fibrillation seen by higher‐billing cardiologists were 26% more likely to have an echocardiogram (adjusted odds ratio [aOR], 1.26 [95% CI, 1.10–1.43] for quintile 5 versus 2), 28% a stress test (aOR, 1.28 [1.12–1.46] for quintile 5 versus 2), 25% continuous electrocardiographic monitoring (aOR, 1.25 [1.08–1.46] for quintile 4 versus 2), and 79% more likely to get a stress echocardiogram (aOR, 1.79 [1.32–2.42] for quintile 5 versus 2). They also had a higher rate of all‐cause hospitalization (aOR, 1.13 [1.07–1.20]). Mortality rates were similar across cardiologists billing quintiles (eg, aOR, 0.98 [0.87–1.11] for quintile 4 versus 2).

Conclusions
Higher‐billing cardiologists ordered more diagnostic tests per patient with atrial fibrillation but these are not associated with improvements in outcomes.
Changing Incidence and Mechanism of Pregnancy‐Associated Myocardial Infarction in the State of California
Authors: Jalnapurkar Sawan , Xu Karen Huaying , Zhang Zhiwei , Bairey Merz C. Noel , Elkayam Uri , Pai Ramdas G. 
Published: October 2021

Background
The objective of this study was to evaluate the temporal trends in pregnancy‐associated myocardial infarction (PAMI) in the State of California and explore potential risk factors and mechanisms.

Methods and Results

The California State Inpatient Database was analyzed from 2003 to 2011 for patients with
International Classification of Diseases, Ninth Revision
(
ICD‐9
) codes for acute myocardial infarction and pregnancy or postpartum admissions; risk factors were analyzed and compared with pregnant patients without myocardial infarction. A total of 341 patients were identified with PAMI from a total of 5 266 380 pregnancies (incidence of 6.5 per 100 000 pregnancies). Inpatient maternal mortality rate was 7%, and infant mortality rate was 3.5% among patients with PAMI. There was a nonsignificant trend toward an increase in PAMI incidence from 2003 to 2011, possibly attributable to higher incidence of spontaneous coronary artery dissection, vasospasm, and Takotsubo syndrome. PAMI, when compared with pregnant patients without myocardial infarction, was significant for older age (aged >30 years in 72% versus 37%,
P
<0.0005), higher preponderance of Black race (12% versus 6%,
P
<0.00005), lower socioeconomic status (median household income in lowest quartile 26% versus 20%,
P
=0.04), higher prevalence of hypertension (26% versus 7%,
P
<0.0005), diabetes (7% versus 1%,
P
<0.0005), anemia (31% versus 7%,
P
<0.0001), amphetamine use (1% versus 0%,
P
<0.00005), cocaine use (2% versus 0.2%,
P
<0.0001), and smoking (6% versus 1%,
P
=0.0001).

Conclusions
There has been a trend toward an increase in PAMI incidence in California over the past decade, with an increasing trend in spontaneous coronary artery dissection, vasospasm, and Takotsubo syndrome as mechanisms. These findings warrant further investigation.