bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fatigue Strength Assessment of a Structure Considering Corrosion Wastage and Corrosion Fatigue
Authors: Yamamoto Norio , Sugimoto Tomohiro , Ishibashi Kinya 
Published: September 2018

It is known that the fatigue strength decreases in corrosive environment and many experiments were carried out to comprehend the decrease in fatigue strength in corrosive environment. In order to comprehend the actual state, a cycle speed of fatigue test loads should correspond to a wave frequency. Therefore, an experiment in the long life region is practically difficult, then the corrosion fatigue data available for the life assessment of the structure is quite limited.
In this study, the fatigue strength of the welded joints in long life service was evaluated according to the calculations of corrosion fatigue crack propagation subjected to the random loadings which followed an exponential distribution. In the crack propagation calculations, the progress of corrosion wastage from the plate surface and the resultant stress increase were considered simultaneously. In the high stress and the short life region, the decrease in fatigue strength due to the accelerated crack propagation in corrosive environment was dominant because the progress of corrosion wastage was little. On the other hand, in the low stress and the long life region, the decrease in fatigue strength became dull as longer the fatigue life because the corrosion fatigue crack propagation was suppressed by the corrosion wastage, but after that the fatigue strength showed the precipitous decrease due to the increase in stress resulted by the progress of corrosion wastage.
Free Span Design Development: Experience With the New Revision of DNVGL-RP-F105
Authors: Vedeld Knut , Sollund Håvar , Fyrileiv Olav 
Published: September 2018

Free spans constitute a threat to the integrity of offshore pipelines. Ocean currents and wave induced flow near the seabed can cause excitation of vortex induced vibrations (VIV), exposing the pipeline to cyclic loading which may result in fatigue failure. In extreme environmental events, waves and currents may cause significant bending moments due to VIV or direct wave loading, which may cause unacceptably high combined loading potentially resulting in pipeline failure. Safe and reliable free span design is therefore a key aspect of pipeline design in general.
When free spans are located in close proximity to each other, modal response may cause span interaction, effectively coupling potential VIV or direct wave action response of two or more spans. Such spans configurations are called multi-spans. Treatment, and particularly identification of multi-span configurations has long been a challenge in the pipeline industry.
In 2017, a new revision of the DNV GL recommended practice for free span pipeline design DNVGL-RP-F105 was issued. Among other subjects, the new revision provides significantly improved guidance on identification and classification of multi-span free spanning pipelines. The new guidance facilitates the option of automating identification, modal analysis and ultimately fatigue analysis of multi-span configurations.
This paper demonstrates background for and benefits with01 the new revision of DNVGL-RP-F105 in systematic and automated treatment of multi-span identification, fatigue and extreme loading assessments based on recent experience from a selection of pipeline design and operations management case studies.
On the Possibility to Compute Slowly-Varying Drift in a CFD Solver
Authors: Monroy Charles , Housseine Charaf Ouled , Malenica Sime 
Published: September 2018

Slowly-varying drift is a phenomenon very familiar to offshore industry, but usually not so much relevant or discussed in naval industry. The classical theoretical background consists in considering a bichromatic wave composed of two regular wave trains of pulsations ω1 and ω2 evolving in the same direction and without any forward speed. The force which varies at low frequency (ω2 – ω1) is known as the slowly-varying drift force and is important in case of moored vessels because it may excite them at their natural periods. The equivalent application in the naval industry is related to maneuvering and added resistance in waves. However, as already indicated, up to the authors’ knowledge, there has not been much work on these issues in the past.
State-of-the-art potential flow tools predict well this slowly-varying drift at zero forward speed. However, with an additional forward speed or a strong current, traditional linear potential codes are outside the scope of their underlying hypothesis and cannot predict accurately the low frequency force. With the constant rise of CPU power and accuracy of CFD solvers, this problem may now be addressed in CFD. The results of foamStar, in-house OpenFOAM solver, will be shown with and without additional forward speed.
Numerical and Experimental Studies on Ship Motions Induced by Passing Ship
Authors: Pedro Francisco G. , Santos João A. , Pinheiro Liliana V. , Fortes Conceição J. , Hinostroza Miguel 
Published: September 2018

To investigate the ability of numerical models to simulate the behavior of moored ships subjected by ship-wake waves, use is made of scale model tests where a ship model sails with constant speed along a straight path at a constant distance from an otherwise motionless ship.
The tests were carried out at one of the wave tanks of the Portuguese Civil Engineering Laboratory (LNEC). The moving ship is a self-propelled scale model of the “Aurora” chemical ship whereas the otherwise motionless ship is a scale model of the “Esso Osaka” tanker. The free-surface elevation was measured with a set of resistive wave gauges and ADVs. The tanker’s movements, induced by the wake waves, were measured along the six degrees of freedom with a gyroscope deployed inside the ship.
The numerical model WAMIT provides, in the frequency domain, the quantities required to estimate the hydrodynamic forces associated to the interaction of a free-floating ship with waves. The BAS model uses those hydrodynamic forces to study in the time domain the ship interaction with any sea-waves acting on it. Wind and current actions can also be accounted for.
The results of these numerical models are compared to the measurements made in the several repeats of one of those scale-model tests, in terms of the response amplitude to several wave components. These comparisons enabled the evaluation and validation of the numerical models parameters’ calibration process.
Wells Turbine With Variable Blade Profile for Wave Energy Conversion
Authors: Miguel González Celia , Rodríguez Fuertes Ginés , García Díaz Manuel , Pereiras García Bruno , Castro Francisco , Fernández Oro Jesus Manuel 
Published: September 2018

It is well known among the researchers involved in the field of turbines for Oscillating Water Column systems (OWC) that the main problem for Wells turbines is the stall, which appears when the main flow incidence angle exceeds certain value and leads to a sharp drop in the efficiency. It also causes problems during the starting, driving the turbine to not reach the designing rotation speed.
Delaying the stall apparition is the key to improve the performance of the Wells turbine. is necessary to delay the flow separation at the trailing edge because it is the reason which leads to the sharp efficiency drop at the stall point.
One of the solutions proposed by researchers in this field is using a variable blade profile instead of the traditional ones, built using constant chord and profile from hub to tip. This work tries to dig deeper in this line by analysing a blade with variable chord and shape among the blade span.
The work has been developed numerically by using commercial software ANSYS FLUENT®. A CFD code was created in order to obtain the performance curve of the turbine proposed to be compared with those assumed as reference, which were taken from the bibliography and also used to validate the numerical model.
The results have shown that an improvement has been achieved. It confirms that using a variable blade profile is a suitable solution to delay the stall apparition.
Stabilized Water-Cut in Carbonate Naturally-Fractured Reservoirs With Bottom Water With an Implication in Well Spacing Design for Recovery Optimization
Authors: Prasun Samir , Wojtanowicz A. K. 
Published: September 2018

Maximum stabilized water-cut (WC), also known as ultimate water-cut in a reservoir with bottom-water coning, provides important information to decide if reservoir development is economical. To date, theory and determination of stabilized water-cut consider only single-permeability systems so there is a need to extend this concept to Naturally Fractured Reservoirs (NFRs) in carbonate rocks — known for severe bottom water invasion. This work provides insight of the water coning mechanism in NFR and proposes an analytical method for computing stabilized water-cut and relating to well-spacing design.
Simulated experiments on a variety of bottom-water hydrophobic NFRs have been designed, conducted, and analyzed using dual-porosity/dual-permeability (DPDP) commercial software. They show a pattern of water cut development in NFR comprising the early water breakthrough and very rapid increase followed by water cut-stabilization stage, and the final stage with progressive water-cut. The initial steply increase of water-cut corresponds to water invading the fractures. The stabilized WC production stage occurs when oil is displaced at a constant rate from matrix to the water-producing fractures. During this stage water invades matrix at small values of capillary forces so they do not oppose water invasion. In contrast, during the final stage (with progressing water cut) the capillary forces grow significantly so they effectively oppose water invasion resulting in progressive water cut.
A simple analytical model explains the constant rate of oil displacement by considering the driving effect of gravity and viscous forces at a very small value of capillary pressure. The constant oil displacement effect is confirmed with a designed series of simulation experiments for a variety of bottom-water NFRs. Statistical analysis of the results correlates the duration of the stabilized WC stage with production rate and well-spacing and provides the basis for optimizing the recovery. Results show that stabilized water-cut stage does not significantly contribute to recovery, so the stage needs to be avoided. Proposed is a new method for finding the optimum well spacing that eliminates the stabilized WC stage while maximizing recovery. The method is demonstrated for the base-case NFR.
Association between physician
US News & World Report
medical school ranking and patient outcomes and costs of care: observational study
Authors: Tsugawa Yusuke , Blumenthal Daniel M , Jha Ashish K , Orav E John , Jena Anupam B 
Published: September 2018

Abstract

Objective

To investigate whether the
US News & World Report
(USNWR) ranking of the medical school a physician attended is associated with patient outcomes and healthcare spending.

Design
Observational study.

Setting
Medicare, 2011-15.

Participants
20% random sample of Medicare fee-for-service beneficiaries aged 65 years or older (n=996 212), who were admitted as an emergency to hospital with a medical condition and treated by general internists.

Main outcome measures
Association between the USNWR ranking of the medical school a physician attended and the physician’s patient outcomes (30 day mortality and 30 day readmission rates) and Medicare Part B spending, adjusted for patient and physician characteristics and hospital fixed effects (which effectively compared physicians practicing within the same hospital). A sensitivity analysis employed a natural experiment by focusing on patients treated by hospitalists, because patients are plausibly randomly assigned to hospitalists based on their specific work schedules. Alternative rankings of medical schools based on social mission score or National Institute of Health (NIH) funding were also investigated.

Results

996 212 admissions treated by 30 322 physicians were examined for the analysis of mortality. When using USNWR primary care rankings, physicians who graduated from higher ranked schools had slightly lower 30 day readmission rates (adjusted rate 15.7% for top 10 schools
v
16.1% for schools ranked ≥50; adjusted risk difference 0.4%, 95% confidence interval 0.1% to 0.8%; P for trend=0.005) and lower spending (adjusted Part B spending $1029 (£790; €881)
v
$1066; adjusted difference $36, 95% confidence interval $20 to $52; P for trend <0.001) compared with graduates of lower ranked schools, but no difference in 30 day mortality. When using USNWR research rankings, physicians graduating from higher ranked schools had slightly lower healthcare spending than graduates from lower ranked schools, but no differences in patient mortality or readmissions. A sensitivity analysis restricted to patients treated by hospitalists yielded similar findings. Little or no relation was found between alternative rankings (based on social mission score or NIH funding) and patient outcomes or costs of care.

Conclusions
Overall, little or no relation was found between the USNWR ranking of the medical school from which a physician graduated and subsequent patient mortality or readmission rates. Physicians who graduated from highly ranked medical schools had slightly lower spending than graduates of lower ranked schools.
Perioperative laryngospasm management in paediatrics: a high-fidelity simulation study
Authors: Michelet Daphné , Truchot Jennifer , Piot Marie-Aude , Drummond David , Ceccaldi Pierre-François , Plaisance Patrick , Tesnière Antoine , Dahmani Souhayl 
Published: September 2018

AimPaediatric anaesthesia is a very specialised domain lacking training during the traditional curriculum. The laryngospasm is a stressful and life-threatening event that requires immediate action. The main objective of this study was to assess the effect of knowledge of a simple algorithm on the management of laryngospasm by trainee anaesthetists and nurse anaesthetists during a high-fidelity simulation session.MethodResidents in paediatric anaesthesia and training nurse anaesthetists with similar curriculum were randomly allocated to undergo a simulation session of laryngospasm with the help of a simple algorithm administered to them 5 min before the simulation session (group A) or as taught in their curriculum (group C). The primary endpoint was the assessment score of laryngospasm management using 10 technical items (validated in experienced paediatric anaesthetists). Secondary endpoints were: the non-technical skills using the Anaesthetists' Non-Technical Skills (ANTS) score and timing of critical management steps. The correlation between the technical and non-technical scores was also studied. Data are expressed as median (range).Results72 participants (18 teams in each group) were included in this study. There was a statistically significant difference between group A and C on the primary endpoint: 8.5 (2–10) vs 5 (2–8), respectively (p<0.0001). There was also a significant difference between the two groups for the ANTS score 12 (7–16) vs 8 (6–12), respectively (p<0.0001). No difference in timing of management was observed. Finally, there was a strong correlation between the technical skills and all the non-technical skills categories in the A group.ConclusionA simple algorithm improved the technical and non-technical skills of students during the management of a simulated laryngospasm.
Long-term quality-adjusted survival following therapeutic bronchoscopy for malignant central airway obstruction
Authors: Ong Philip , Grosu Horiana B , Debiane Labib , Casal Roberto F , Eapen George A , Jimenez Carlos A , Noor Laila , Ost David E 
Published: September 2018

BackgroundWhile therapeutic bronchoscopy has been used to treat malignant central (CAO) airway obstruction for >25 years, there are no studies quantifying the impact of therapeutic bronchoscopy on long-term quality-adjusted survival.MethodsWe conducted a prospective observational study of consecutive patients undergoing therapeutic bronchoscopy for CAO. Patients had follow-up at 1 week and monthly thereafter until death. Outcomes included technical success (ie, relief of anatomic obstruction), dyspnoea, health-related quality of life (HRQOL) and quality-adjusted survival.ResultsTherapeutic bronchoscopy was performed on 102 patients with malignant CAO. Partial or complete technical success was achieved in 90% of patients. At 7 days postbronchoscopy, dyspnoea improved (mean ∆Borg-day-7=−1.8, 95% CI −2.2 to −1.3, p<0.0001) and HRQOL improved (median prebronchoscopy 0.618 utiles, 25%–75% IQR 0.569 to 0.699, mean ∆utility-day-7+0.047 utiles, 95% CI +0.023 to 0.071, p=0.0002). Improvements in dyspnoea and HRQOL were maintained long-term. Compared with the prebronchoscopy baseline, HRQOL per day of life postbronchoscopy improved (mean ∆utility-long-term+0.036 utiles, 95% CI +0.014 to 0.057, p=0.002). Median quality-adjusted survival was 109 quality-adjusted life-days (QALDs) (95% CI 74 to 201 QALDs). Factors associated with longer quality-adjusted survival included better functional status, treatment-naïve tumour, endobronchial disease, less dyspnoea, shorter time from diagnosis to bronchoscopy, absence of cardiac disease, bronchoscopic dilation and receiving chemotherapy.ConclusionsTherapeutic bronchoscopy improves HRQOL as compared with baseline, resulting in approximately a 5.8% improvement in HRQOL per day of life. The risk-benefit profile in these carefully selected patients was very favourable.Trial registration numberResults; NCT03326570.
Influence of streambank fencing on vegetation and soil of the Mixed prairie component in a complex corridor pasture
Authors: Miller J.J. , Curtis T. , Willms W.D. , Chanasyk D.S. 
Published: September 2018

A 5 yr (2011–2015) field study was conducted to test the hypothesis that streambank fencing had a significant effect on selected vegetation and soil properties of the Mixed prairie component of a complex corridor pasture. The grazing treatments [ungrazed (UG) – periodic grazing (PG)] inside the corridor pasture were 11 yr (2001–2012) of cattle exclusion (UG), followed by 3 yr (2013–2015) of periodic grazing (PG) when the riparian soil was dry. A control treatment outside the fencing was continuous grazing (CG). Selected vegetation and soil properties were measured over the growing season at 10 paired locations in each treatment (nonreplicated) pasture over 5 yr (2011–2015), and rangeland health was measured in 2011. The UG–PG treatment significantly (P ≤ 0.10) increased the total biomass by 2- to 5-fold in all 5 yr compared with CG treatment and improved the rangeland health score of the UG phase of the UG–PG (63%) treatment compared with the CG treatment (50%) in 2011. It also significantly reduced surface soil temperature by 2.2–5.2 °C, significantly increased volumetric water content of the surface soil by 7%–10% in 3 of 5 yr, and significantly increased surface soil CO2 efflux (instantaneous) by 17%–60% in all 5 yr. Overall, the UG–PG treatment improved rangeland health, increased total biomass, soil water, and soil CO2 efflux of the Mixed prairie, but decreased soil temperature compared with the CG treatment. Excessive dead biomass, greater fire risk, and an increase in noxious weeds caused by cattle exclusion suggested that periodic grazing may be the preferred option.
Acute dopamine receptor blockade in substantia nigra pars reticulata: a possible model for drug-induced Parkinsonism
Authors: Cáceres-Chávez Verónica Alejandra , Hernández-Martínez Ricardo , Pérez-Ortega Jesús , Herrera-Valdez Marco Arieli , Aceves Jose J. , Galarraga Elvira , Bargas José 
Published: September 2018

Dopamine (DA) depletion modifies the firing pattern of neurons in the substantia nigra pars reticulata (SNr), shifting their mostly tonic firing toward irregularity and bursting, traits of pathological firing underlying rigidity and postural instability in Parkinson’s disease (PD) patients and animal models of Parkinsonism (PS). Drug-induced Parkinsonism (DIP) represents 20–40% of clinical cases of PS, becoming a problem for differential diagnosis, and is still not well studied with physiological tools. It may co-occur with tardive dyskinesia. Here we use in vitro slice preparations including the SNr to observe drug-induced pathological firing by using drugs that most likely produce it, DA-receptor antagonists (SCH23390 plus sulpiride), to compare with firing patterns found in DA-depleted tissue. The hypothesis is that SNr firing would be similar under both conditions, a prerequisite to the proposal of a similar preparation to test other DIP-producing drugs. Firing was analyzed with three complementary metrics, showing similarities between DA depletion and acute DA-receptor blockade. Moreover, blockade of either nonselective cationic channels or Cav3 T-type calcium channels hyperpolarized the membrane and abolished bursting and irregular firing, silencing SNr neurons in both conditions. Therefore, currents generating firing in control conditions are in part responsible for pathological firing. Haloperidol, a DIP-producing drug, reproduced DA-receptor antagonist firing modifications. Since acute DA-receptor blockade induces SNr neuron firing similar to that found in the 6-hydroxydopamine model of PS, output basal ganglia neurons may play a role in generating DIP. Therefore, this study opens the way to test other DIP-producing drugs. NEW & NOTEWORTHY Dopamine (DA) depletion enhances substantia nigra pars reticulata (SNr) neuron bursting and irregular firing, hallmarks of Parkinsonism. Several drugs, including antipsychotics, antidepressants, and calcium channel antagonists, among others, produce drug-induced Parkinsonism. Here we show the first comparison between SNr neuron firing after DA depletion vs. firing found after acute blockade of DA receptors. It was found that firing in both conditions is similar, implying that pathological SNr neuron firing is also a physiological correlate of drug-induced Parkinsonism.