bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Numerical Investigation Into Hydrodynamic Interaction Coefficients for Multiple Freely Floating Bodies in Waves
Authors: Ali Mir Tareque 
Published: December 2020

Abstract
When two or more bodies are floating in waves in each other’s vicinity, the fluid loading on the separate bodies will be influenced by the presence of the neighboring bodies. The wave loads on each body are affected, because of sheltering or wave-reflection effects due to the presence of surrounding floating body, while additional loads are exerted by the radiated waves, which are produced by the motions of the neighboring bodies. For a multi-body system, it is important to accurately compute the hydrodynamic coefficients and interaction coefficients, since these parameters will be used later to solve the 6xN simultaneous equations to predict the motion responses (where N is the number of freely floating bodies in the multi-body system). This paper aims to investigate the hydrodynamic interaction coefficients for two three dimensional (3-D) bodies floating freely in each other’s vicinity. Since the nature of hydrodynamic interaction is rather complex, it is usually recommended to study this complicated phenomenon using numerically accurate scheme. A computer code developed using 3-D source distribution method which is based on linear three-dimensional potential theory is used and the validation of the computer code has been justified by comparing the present results with that of the published ones for hydrodynamic coefficients and interaction coefficients of two bodies closely floating in regular waves. The calculated results for box-cylinder model are compared with the published results and the agreement is quite satisfactory. Numerical simulations are further conducted for two closely floating rectangular barges of side-by-side position in regular waves. During the computations of hydrodynamic coefficients and interaction coefficients for multi-body model, the separation distance between the floating bodies have been varied. Finally, some conclusions are drawn on the basis of the present analysis.
Investigation of Stick-Slip Severity in a Coupled Axial-Torsional Drillstring Dynamics Using a Two DOF Finite Element Model
Authors: Wiktorski Ekaterina , Sui Dan 
Published: December 2020

Abstract
Drilling industry focuses nowadays on process optimization and cost reduction. Unwanted events should be predicted and avoided to increase drilling efficiency, improve safety, and save costs. Development and application of mathematical models enable us to understand the dynamics of the drilling process, learn parameter interaction and regulate system behavior. It is also a way to reduce the risk of occurrence of such events or mitigate negative outcomes.
Challenges in two-dimensional modeling of drillstring vibrations include: (1) correct and precise interpretation of coupled two-dimensional motion, (2) use of sub-models, as down-hole weight on bit (WOB) model, downhole torque on bit (TOB) model and friction model, and (3) proper definition of associated boundary conditions. In this paper, we propose a two-dimensional axial-torsional model that considers these criteria. We present a new way to calculate downhole WOB, which can be used as an alternative to a constant WOB value. Dynamic boundary conditions are introduced to represent the respective phases of stick-slip. The model is formulated using the finite element method and intended for vertical wells. The main goal for developing this model is evaluation of the effect of surface rotational and axial velocities on the downhole drill bit dynamics. A dimensionless parameter, stick-slip severity, is used to represent the intensity of torsional oscillations.
The developed model is based on mathematical relations and defined boundary conditions, which describe the dynamics of drillstring during stick-slip events. The model allows to study the effect of up to twelve input parameters on stick-slip severity to determine a suitable range. Results presented in this paper show that axial velocity applied from the surface may cause initiation of stick-slip, which in turn provokes axial vibrations. Increase in surface axial velocity leads to higher amplitude of downhole torsional oscillations. To mitigate stick-slip, surface rotational velocity should be increased.
Calculation of Fatigue Capacity for a Subsea Wellhead Connector
Authors: Hashemizadeh Seyed H. , Sunkavilli Venu , Hørte Torfinn , Osen Per 
Published: December 2020

Abstract
In the 2019 version of DNVGL-RP-C203 Fatigue Design of Offshore Steel Structures, significantly improved methods have been added on how to establish M-N curves representing the fatigue resistance of preloaded connectors subject to cyclic bending. The M-N curve parameters are typically provided by the manufacturer and used by operators and drilling contractors for calculating the wellhead fatigue life for planned drilling operations.
DNVGL-RP-C203 provides specific advice on how to establish design M-N curves based on analysis, and the augmentation by possible testing, where testing may grant more favorable M-N curves and thus extended fatigue life for any given case.
The paper provides background and introduction to the improved analysis methodology and relevant S-N curves for high-strength steels for wellhead systems, given in the 2019 version of the DNVGL-RP-C203. It includes a worked example in order to demonstrate the detailed use of the method, applied on a Baker Hughes preloaded BOP connector, connected to a 27” wellhead mandrel. This example describes the finite element model set up, FE model mesh refinement in hot-spots, the application of cyclic loads, extraction of hot-spot cyclic stresses, and the establishment of the M-N curve for the connector.
Model Test Study on Anti-Rolling of Ship at Zero Speed
Authors: Wei Yuefeng , Yang Yi , Fan Sheming , Liu Zhen , Feng Peiyuan 
Published: December 2020

Abstract
Model test is carried out to study the anti-rolling method of ship at zero speed in the present paper. First of all, based on the longitudinal flap mode, a zero speed fin stabilizer is designed. Furthermore, a control strategy for anti-rolling of ship at zero speed is proposed. At last, both regular and irregular wave tests are performed in towing tank. It can be shown from the test results that anti-rolling effectiveness of the zero speed fin stabilizer is obvious. Under level four sea condition, the effectiveness of anti-rolling is more than 40%. And under level five sea condition, the effectiveness of anti-rolling is more than 35%.
A General Nonlinear Wavemaker Theory for Intermediate- to Deep-Water Waves Using Inverse Scattering Transform
Authors: Mohtat Ali , Yim Solomon C. , Adami Nasim , Lomonaco Pedro 
Published: December 2020

Abstract
Analysis and generation of (nonlinear) intermediate- to deep-water waves with large steepness in experimental facilities are some of the most challenging tasks in wave mechanics. The inherent instability of water waves in deep-water waves makes the linear-based wave generation and analysis less accurate and incapable of generating and characterizing correctly nonlinear behavior of the target wave field. In this presented research, a detailed assessment of the wavemaker theories and steps included in experimental approaches are presented. After establishing the nonlinear behavior of generated intermediate- to deep-water waves, a novel wavemaker theory based on the nonlinear Schrödinger equation is proposed. The implementation of the proposed wavemaker theory shows its capability of generating deep-water waves more accurately and preserving the correct order of nonlinearity.
Minimal stratigraphic evidence for coseismic coastal subsidence during 2000 yr of megathrust earthquakes at the central Cascadia subduction zone
Authors: Nelson Alan R. , Hawkes Andrea D. , Sawai Yuki , Horton Ben P. , Witter Rob C. , Bradley Lee-Ann , Cahill Niamh 
Published: December 2020

AbstractLithology and microfossil biostratigraphy beneath the marshes of a central Oregon estuary limit geophysical models of Cascadia megathrust rupture during successive earthquakes by ruling out &gt;0.5 m of coseismic coastal subsidence for the past 2000 yr. Although the stratigraphy in cores and outcrops includes as many as 12 peat-mud contacts, like those commonly inferred to record subsidence during megathrust earthquakes, mapping, qualitative diatom analysis, foraminiferal transfer function analysis, and 14C dating of the contacts failed to confirm that any contacts formed through subsidence during great earthquakes. Based on the youngest peat-mud contact’s distinctness, &gt;400 m distribution, ∼0.6 m depth, and overlying probable tsunami deposit, we attribute it to the great 1700 CE Cascadia earthquake and(or) its accompanying tsunami. Minimal changes in diatom assemblages from below the contact to above its probable tsunami deposit suggest that the lower of several foraminiferal transfer function reconstructions of coseismic subsidence across the contact (0.1–0.5 m) is most accurate. The more limited stratigraphic extent and minimal changes in lithology, foraminifera, and(or) diatom assemblages across the other 11 peat-mud contacts are insufficient to distinguish them from contacts formed through small, gradual, or localized changes in tide levels during river floods, storm surges, and gradual sea-level rise. Although no data preclude any contacts from being synchronous with a megathrust earthquake, the evidence is equally consistent with all contacts recording relative sea-level changes below the ∼0.5 m detection threshold for distinguishing coseismic from nonseismic changes.
Synthesis, XRD analysis and electronic structure of InGaTe2 chain semiconductor
Authors: Gojayev E. M. , Osmanova S. S. , Safarova S. I. , Gafarova D. M. 
Published: December 2020

In this work, we developed a technology for growing a single crystal of a ternary compound, using the Atomic Force Microscope (AFM), we studied the surface microrelief in 2D and 3D modes, using X-ray diffraction (XRD) analysis, determined the parameters of the unit cell of this phase and revealed that it crystallizes in tetragonal symmetry with lattice parameters [Formula: see text] Å and [Formula: see text] Å, space group I4/mcm. Using the density functional method, using the ABINIT software package, using the Troiller–Martins pseudopotentials in the basis of plane waves, the band structure was calculated, the origin of the valence and conduction bands was determined. It was revealed that this phase is a direct-gap semiconductor with a bandgap of 0.56 eV. The parameters of the InGaTe2 unit cell were calculated by the pseudopotential and linearized attached plane wave (LAPW) methods, the theoretical and experimental values of the lattice parameters are in good agreement. Based on the band structure, the effective masses of electrons and holes are determined. It is shown that the tensors of the inverse effective mass for both extreme have a diagonal form.
Analyzing opto-electronic and transport characteristics of ZnSc2Se4and CdSc2Se4spinels for opto-electronic and energy storage devices
Authors: Mahmood Asif , Ramay Shahid M. , Al-Masry Waheed , Al-Zahrani Ateyah A. , Al-Garadi Najib Y. A. 
Published: December 2020

ZnSc2Se4and CdSc2Se4spinels in cubic phase are analyzed by using ab-initio total energy calculations in order to examine their structure along with optoelectronic and thermoelectric characteristics. We used Perdew–Burke–Ernzerhof (PBEsol) generalized gradient approximation (GGA) to evaluate the structural parameters and found that our predicted parameters are good compared with existing other theoretical and experimental results. In addition, we employed the recently developed modified Becke and Johnson (mBJ) potential for the prediction of accurate electronic bandgap measurements of ZnSc2Se4and CdSc2Se4. By employing mBJ potential, direct bandgap nature of studied spinels is absorbed from electronic band structure plots, which indicate that bandgap decreases as cation Zn is replaced by Cd. Predicted values of bandgap are [Formula: see text] eV for ZnSc2Se4and [Formula: see text] eV for CdSc2Se4using mBJ potential representing the studied spinels which play a vital role in the field of opto-electronic devices operating in visible range of spectrum. On the basis of direct bandgaps nature, we also investigate optical characteristic in detail as a function of incident photon energy (0–12 eV). Further, electronic transport characteristic of studied spinels is also investigated with respect to temperature (K) and chemical potential (eV) for their application in energy storage devices.
Long‐Term Clinical Outcomes Following Revascularization in High‐Risk Coronary Anatomy Patients With Stable Ischemic Heart Disease
Authors: Bainey Kevin R. , Alemayehu Wendimagegn , Welsh Robert C. , Kumar Arnav , King Spencer B. , Kirtane Ajay J. 
Published: December 2020

Background
The ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches) trial failed to show a reduction in hard clinical end points with an early invasive strategy in stable ischemic heart disease (SIHD). However, the influence of left main disease and high‐risk coronary anatomy was left unaddressed. In a large angiographic disease‐based registry, we examined the modulating effect of revascularization on long‐term outcomes in anatomically high‐risk SIHD.

Methods and Results

9016 patients with SIHD with high‐risk coronary anatomy (3 vessel disease with ≥70% stenosis in all 3 epicardial vessels or left main disease ≥50% stenosis [isolated or in combination with other disease]) were selected for study from April 1, 2002 to March 31, 2016. The primary composite of all‐cause death or myocardial infarction (MI) was compared between revascularization versus conservative management. A total of 5487 (61.0%) patients received revascularization with either coronary artery bypass graft surgery (n=3312) or percutaneous coronary intervention (n=2175), while 3529 (39.0%) patients were managed conservatively. Selection for coronary revascularization was associated with improved all‐cause death/MI as well as longer survival compared with selection for conservative management (Inverse Probability Weighted hazard ratio [IPW‐HR] 0.62; 95% CI 0.58 to 0.66;
P
<0.001; IPW‐HR 0.57; 95% CI 0.53–0.61;
P
<0.001, respectively). Similar risk reduction was noted with percutaneous coronary intervention (IPW‐HR 0.64, 95% CI 0.59–0.70,
P
<0.001) and coronary artery bypass graft surgery (IPW‐HR 0.61; 95% CI 0.57–0.66;
P
<0.001).

Conclusions
Revascularization in patients with SIHD with high‐risk coronary anatomy was associated with improved long‐term outcome compared with conservative therapy. As such, coronary anatomical profile should be considered when contemplating treatment for SIHD.
The Horseshoe whip snake (Hemorrhois hippocrepis) on Ibiza: predator release in an invasive population
Authors: Montes Elba , Feriche Mónica , Alaminos Esmeralda , Pleguezuelos Juan Manuel 
Published: December 2020

Abstract
The key to fighting a biological invasion may lie in understanding every variable that can explain its success. The Enemy Release Hypothesis (ERH) states that when an invader arrives to a new environment, the absence of its common enemies (predators, parasites and competitors) facilitates the invasion success. The Horseshoe whip snake (Hemorrhois hippocrepis) has been recently introduced from the Iberian Peninsula to the island of Ibiza, and it is currently threatening the only endemic vertebrate, the Ibiza wall lizard (Podarcis pityusensis). We hypothesized that the snake invasion success is caused by the absence of natural predators, and we checked the ERH by relating the tail breakage rate to predation pressure. The invasive population showed a much lower incidence of tail breakage than the source population, which is in agreement with the almost absence of snake predators among the Ibizan reduced and naïve native vertebrate community. These results confirm the ERH, and support the prolongation of invasive snake trapping campaigns.
Entheogenic Experience and Spirituality
Authors: Johnstad Petter Grahl 
Published: December 2020

Abstract
Spiritual experiences with entheogens have usually been studied as a form of mystical experiences. However, entheogen users have also reported less intense experiences that they refer to as spiritual experiences. Using data from the Cannabis and Psychedelics User Survey, this study analyzed the characteristics of such experiences in 319 participants. It found evidence of two types of entheogenic experience that may be called spiritual. The first involved mystical-type characteristics and was predicted in multivariate linear regression models by the spirituality of the participants, operationalized as a spiritual affiliation, motivation, and practice. The second type involved characteristics representing insight, positive feelings, and improved connections to other people and to nature. This type of entheogenic experience was predicted by spiritual motivation, but not by spiritual affiliation or practices. The article discusses the implications of these findings, which may indicate competing conceptualizations of spirituality among the participants in the study.
Abdominal Wall Thickness is a Predictor for Surgical Site Infections in Patients Undergoing Colorectal Operations
Authors: Chang Yu-Wei W. , Murphy Kyle , Yackzan Daniel , Thomas Sarah , Kay Danielle , Davenport Daniel , Evers Bernard M. , Bhakta Avinash S. 
Published: December 2020

Background Surgical site infections (SSIs) are an established complication following colorectal operations, with rates up to 30% reported in the literature. Obesity is a known risk factor for SSI; however, body mass index (BMI), body fat percentage, waist-hip ratio, or abdominal circumference are imperfect measures. The purpose of our study was to determine whether abdominal wall thickness (AWT) is predictive of SSI. Methods We queried our American College of Surgeons National Surgical Quality Improvement Project (ACS-NSQIP) database for patients (age ≥18 years) undergoing a colectomy at the University of Kentucky (UK) from January 1, 2013 to December 31, 2018. The exclusion criteria included patients with open abdomens or the lack of preoperative computed tomography (CT) within 3 months of their operation. AWT was measured at the level of the anterior superior iliac spine (ASIS) on abdominal CT. SSI was defined by superficial SSI, deep SSI, and wound dehiscence. Results Of 1261 patients enrolled, 52.2% were female, with an average age of 57.4 years. More patients had laparoscopic operations (51%), and the median length of stay was 7 days. Our study demonstrated an SSI rate of 9.4% and a 30-day readmission rate of 11%. The overall mean AWT was 2.6 cm (range .1-13.1), and patients with the highest AWT quintile were more likely to develop an SSI than the lowest quintile (12% vs. 5%). After controlling for risk factors and confounders, the odds of an SSI were 3.6 times higher for patients with the highest AWT than patients with the lowest AWT. Conclusions Among colorectal surgery patients, AWT is an independent risk factor predictive for SSI.
Congenital Diaphragmatic Hernia: Demographics and 30-day Outcomes in Adults
Authors: Brungardt Joseph G. , Nix Quinn A. , Schropp Kurt P. 
Published: December 2020

Background Congenital diaphragmatic hernia (CDH) is a pathology most often affecting the pediatric population, although adults can also be affected. Few studies exist of adults undergoing repair of this defect. Using a national database, we sought to determine demographics and outcomes of this population. Methods An analysis of the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database (2015-2018) was performed, capturing patients with postoperative diagnosis of CDH, distinct from ventral hernia. Two groups were created based upon surgical approach of open or minimally invasive (MIS) repair. Baseline demographics and outcomes were compared. Results 110 patients undergoing surgical correction of CDH were captured in the database. We found rates of return to the operating room (4.55%), postoperative respiratory failure (5.45%), and reintubation (3.64%) with no difference between groups. There was no mortality and no difference between groups in length of operation, discharge to home, or postoperative complications. Patients undergoing open repair had a longer length of stay than patients in the MIS group (6.47 ± 10.76 days vs. 3.68 ± 3.74 days, P = .0471). Mesh was used in MIS more often than the open group (47.30% vs. 5.56%, P < .0001). Discussion This study describes rates of postoperative complications in patients undergoing repair of CDH, and suggests outcomes those are equivalent between patients receiving open or MIS approaches. Further case series or retrospective studies are needed to further describe this population of patients.
Antibiotic Exposure Is Not Associated With Clearance of Bronchoalveolar Growth: Results From a Prospective Ventilator-Associated Pneumonia Study
Authors: Betzold Richard D. , Dennis Bradley M. , Bellister Seth A. , Guidry Christopher A. , Guillamondegui Oscar D. , Drake Wonder , May Addison K. 
Published: December 2020

Background Ventilator-associated pneumonia is poorly understood in trauma. Ventilated trauma patients can develop bacterial burden without symptoms; the factors that influence this are unknown. Methods Injured adults ventilated for > 2 days were enrolled. Mini-bronchoalveolar lavage was performed for 14 days or until extubation. Semi-quantitative cultures were blinded from clinicians. All cultures with > 104 colony forming units (CFU) were assessed for antibiotic exposure (ABXE) and spectrum of coverage. mBAL CFU was assessed daily. Results 60 patients were ventilated for 9 days (median). There were 75 with > 104 CFU. 46 had > 104 CFU and no ABXE on the sample day. 74% had clearance or a decrease (CoD) in CFU without ABXE. 29 had > 104 CFU and ABXE on the sample day. 19 had ABXE with pathogen coverage. 84% had CoD in CFU. 10 had ABXE with no spectrum of coverage. 1/10 had increased CFU and the remaining 9/10 CoD in CFU. The three groups were not statistically different on chi-squared analysis. Conclusion Clearance of pathogens on surveillance cultures was unaffected by ABXE.