bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surge Response Control of FPSO Using Multiple Tuned Liquid Dampers: A Study on Effect of Multiple Frequencies in TLD
Authors: Gurusamy Saravanan , Kumar Deepak 
Published: November 2019

Abstract
Industries rely mostly on off-shore resources to fulfill the increase in demand for oil and gas. In general, for oil extraction and various other refinery processes, fixed or floating structures are being utilized. Floating Production Storage and Offloading (FPSO) system is one of the floating systems which have advantage of storing the crude oil and, if required, it can be easily moved to other places. Also, in deep Ocean where sub-sea pipeline infrastructures are often not possible and so the FPSOs give alternate option of storing and processing the crude oil. Being moored-systems, FPSOs are very flexible structures having high surge natural period and hence they may undergo larger surge displacement. Excessive displacement may cause damage for the riser system also it may affect the workability under extreme sea condition. Therefore, there is a need for investigating the issues of safety, efficiency and response control of FPSO systems under different sea-state conditions. Ocean wave loads on FPSO causes dynamic interaction between FPSO vessel and liquid in the oil storage containers. The liquid motion in containers disturbs the dynamics of the vessel significantly. Hence, it is essential to study the surge response control of FPSO in detail.
An easy way to control the response is to use the existing cargo containers of FPSO as passive damping devices. If the natural frequency of liquid oscillation is tuned to the natural frequency of FPSO, these cargo tanks can act as Multiple Tuned Liquid Dampers (MTLDs). In case of simple linear model, Tuned liquid damper (TLD) can be idealized as a Single Degree of Freedom (SDOF) system, namely Tuned Mass Damper (TMD). The present study attempts to model a TLD using three different TMD systems to account the effects of shallow water sloshing.
Port Channel Navigation Subjected to Environmental Conditions Using Reinforcement Learning
Authors: Amendola José , Tannuri Eduardo A. , Cozman Fabio G. , Reali Costa Anna H. 
Published: November 2019

Abstract
This paper proposes a machine learning agent for automatically navigating a vessel in a confined channel subject to environmental conditions. The agent is trained and tested using a Ship Maneuvering Simulator and is responsible for commanding the rudder, so as to keep the vessel inside the channel with minimum distance from the center line, and to reach the final part of the channel with a prescribed thruster rotation level. The algorithm is based on deep reinforcement learning method and uses an efficient state-space representation. The advantage of using reinforcement learning is that it does not require any expert to directly teach the agent how to behave under particular conditions. The novelty of this work is that: it does not require previous knowledge on the vessel dynamic model and the maneuvering scenario; it is robust against fluctuations of environmental forces such as wind and current; it considers discrete actions of rudder commands emulating the pilot actions in a real maneuver. The developed method is convenient for simulations in scenarios or areas that were never navigated before, in which no previous navigation data can be used to train a conventional supervised learning agent. One direct application for this work is the integration with a realistic fast-time maneuvering simulator for new ports or operations. Both training and validation experiments focused on the unsheltered approach channel of the Suape Port, in Brazil; these experiments were run in a SMH-USP maneuvering simulator (real environmental conditions measured on-site were employed in simulations).
Frequency Domain Analysis of a Hybrid Aquaculture-Wind Turbine Offshore Floating System
Authors: Abhinav K. A. , Collu Maurizio , Ke Sun , Binzhen Zhou 
Published: November 2019

Abstract
The aquaculture industry is being pushed into deeper waters, to accommodate the increasing demand for seafood worldwide and the lack of nearshore sites: aquaculture systems for farther, harsher conditions are now being proposed. The Blue Growth initiative by the European Union is also tuned in the same direction, with the focus being on developing ocean based resources, including energy and aquaculture, and finding synergies among them.
The present work proposes a novel multi-purpose platform (MPP), by retrofitting a feed barge with a small wind turbine and energy storage system, able to provide sustainable energy to a reference offshore aquaculture farm. The requirements and constraints for such hybrid system are defined, as well as a set of keys load cases, and its performance are analysed in the frequency domain. Wave loads are modelled using linear potential theory, while from an aerodynamic point of view, only the maximum thrust at the wind turbine hub level is considered in the static stability analysis. With reference to stability criteria and dynamic analysis in frequency domain, the suitability of the proposed MPP to act as a source of feed storage and energy supply is established, showing this as a potentially suitable solution.
A Benchmarking Exercise on Estimating Extreme Environmental Conditions: Methodology and Baseline Results
Authors: Haselsteiner Andreas F. , Coe Ryan G. , Manuel Lance , Nguyen Phong T. T. , Martin Nevin , Eckert-Gallup Aubrey 
Published: November 2019

Abstract
A wide range of methods have been proposed for the derivation of environmental contours for marine structures that must meet reliability targets. An environmental contour is a set of joint extremes of environmental conditions associated with a target return period. In general, environmental contour methods help with the prediction of some future critical combinations of environmental conditions (e.g., wind, waves, current) at a location of interest based on a limited dataset, thus allowing designers to ensure a prescribed structural reliability. In fact, some of these contour methods are specifically recommended by technical specifications and standards as part of a design process. This paper outlines the rules and procedures for a collaborative benchmarking exercise — focused on open comparison — in which researchers are invited to develop and present their own contour derivation approaches based on common datasets that will be available to all. Hindcast and observational datasets are considered and two exercises are planned: One focuses on applying environmental contour methods to a wide range of datasets and the other focuses on uncertainty characterization. Besides describing the benchmark’s methodology, this paper presents baseline results of computed contours following current recommendations. The overall goals of this endeavor are: (i) to work towards the development of more robust statistical models and contour construction methods, (ii) to encourage increased discussion in the international research community and among practitioners, and (iii) to support ongoing efforts to improve technical specifications and standards.
Experimental Study of Pipe Pulling Through Settled Barite
Authors: Taghipour Ali , Vrålstad Torbjørn , Skorpa Ragnhild , Bhuiyan Mohammad Hossain , Ytrehus Jan David , Stroisz Anna 
Published: November 2019

Abstract
Wells are essential in oil and gas production and construction of them is one of the main cost drivers for field development. It is normally needed to drill and construct new wells from existing fields during most of the production time. In order to reduce costs one can re-use parts of existing wells when they are no longer efficient. This is done in offshore fields also when there is limitation for new wells due to capacity of the subsea template. Through tubing drilling is a method to drill a side track through the wellbore tubulars. However, this will normally result in a smaller and less effective well completion.
Removing parts of the casing section and drill a larger size sidetrack is an option to provide a new full-size wellbore. Removing the 9 5/8” casing through the settled particle in the annulus can be challenging. The wellbore annulus is normally filled with old drilling fluid, displacing fluid and/or cement slurry. The solid particles of these annular fluids are settled during years of shut-in and make it difficult to move the casing sections. There are several techniques for pulling the casing section, but there is a lack of knowledge of some of the key mechanism causing the resistance in these operations.
In order to study and address the dominating effects in these operations, down-scaled laboratory tests are performed. The experiments reported here are performed by pulling steel pipes through the settled barite in the annulus. The pipes used in the tests are down-scaled from typical casing sizes with and without collars. The barite slurry compacted inside the annulus have different hydrostatic and pore pressures. When the pipe is pulled the required mechanical force is measured.
Results show that the single most significant factor causing resistance when pulling the tubulars is the collars outside the pipe. Furthermore, it is identified that the pore pressure improves the mobility of the settled particle around the collar. In total these results provide improved understanding on the dominating factors during pulling pipes from a packed annulus.
Eigen-Solution for Flow Induced Oscillations (VIV and Galloping) Revealed at the Fluid-Structure Interface
Authors: Bernitsas Michael M. , Ofuegbe James , Chen Jau-Uei , Sun Hai 
Published: November 2019

Abstract
Consistent rather than heuristic nondimensionalization of the fluid and oscillator dynamics in fluid-structure interaction, leads to decoupling of amplitude from frequency response. Further, recognizing that the number of governing dimensionless parameters should decrease, rather than increase, due to the fluid-structure synergy at the interface, an eigen-relation is revealed for a cylinder in Flow Induced Oscillations (FIO), including VIV and galloping: mA/mbod = CA/m* = 1/f*2-1. It shows that, for a given dimensionless oscillation frequency f*, the ratio of real added-mass to oscillating-mass is fully defined. Amplitude decoupling and the eigen-relation, lead to explicit expressions for coefficients, phases, and magnitudes of total, added-mass, and in-phase-with-velocity forces; revealing their dependence on the generic Strouhal number (Stn = fn*), damping, and Reynolds. Heuristic dimensionless parameters, (mass-damping, reduced velocity, mass-ratio, force coefficients) used in VIV data presentation are not needed. Theoretical derivations and force reconstruction match nearly perfectly with extensive experimental data collected over a decade in the Marine Renewable Energy Laboratory (MRELab) at the University of Michigan using four different oscillator test-models. Beyond the single frequency response model, the residuary force is derived by comparison to experiments. Established facts regarding VIV and galloping and new important observations are readily explained: (1) The effects of Strouhal, damping-ratio, mass-ratio, Reynolds, reduced velocity, and stagnation pressure. (2) The cause of expansion/contraction of the VIV range of synchronization. (3) The corresponding slope-change in oscillation frequency with respect to the Strouhal frequency of a stationary-cylinder. (4) The critical mass-ratio m* implying perpetual VIV. (5) The significance of the natural frequency of the oscillator in vacuo. (6) The effect of vortices on VIV and galloping. (7) The magnitude of vortex forces. (8) The indirect and direct vortex effects. (9) The unification of VIV and galloping onset. (10) Defining the next step in higher order theories for VIV and galloping beyond the eigen-relation.
Environmentally Assisted Fatigue Data From the INCEFA-PLUS Project
Authors: Bruchhausen Matthias , McLennan Alec , Cicero Roman , Huotilainen Caitlin , Mottershead Kevin , le Roux Jean-Christophe , Vankeerberghen Marc 
Published: November 2019

Abstract
The European project INCEFA-PLUS characterises environmentally assisted fatigue in light water reactor conditions. The project aims at developing a new procedure to assess environmentally assisted fatigue damage susceptibility in nuclear power plant components.
The basis for the development of a new fatigue assessment procedure is a major test campaign carried out in eleven different laboratories across Europe which will deliver approximately 200 fatigue tests. The test campaign is based on a common test matrix that was optimized by means of the Design of Experiments method. The initial focus of the project is on the effects and interactions between the factors strain range, environment (air and light water reactor environment), surface finish, hold time, and mean strain. Whereas the bulk of the test program is carried out on a single heat of 304L austentic steel, some tests on different heats of 304L or other austenitic steels allow studying the influence of material variability.
To guarantee the quality of the data, the tests are performed according to commonly agreed specifications based on ISO 12106 and each test is validated by a group of experts from within the project.
The paper presents the test procedures, provides an overview of the data that has been acquired so far, and gives an outlook on the tests that will be carried out during the final stage of the project.
Hydrogen Effects on Fracture Toughness of Additively Manufactured Type 304L Stainless Steel
Authors: McWilliams Anthony , Morgan Michael , Korinko Paul 
Published: November 2019

Abstract
Rectangular blocks of Type 304L stainless steel were additively manufactured (AM) using the directed energy deposition process. These samples were characterized using tensile, fracture toughness, fractography, and metallography and compared to forged Type 304L steel. The AM materials exhibited high density, tensile properties consistent with mechanically deformed stainless steel, and acceptable fracture toughness properties (&gt; 100 Mpam) in the as fabricated and hydrogen charged (approximately 2500 appm) conditions.
Guerrero-Morelos carbonate platform response to the Caribbean-Colombian Cretaceous large igneous province during Cenomanian–Turonian oceanic anoxic event 2
Authors: Bomou* Brahimsamba , Adatte Thierry , Arnaud-Vanneau Annie 
Published: November 2019

ABSTRACT
The Guerrero-Morelos carbonate platform (southwestern Mexico) is one of the rare platforms that persisted throughout the Cenomanian–Turonian oceanic anoxic event 2 (OAE 2). Two sections from this carbonate platform exhibit the typical δ13C positive excursion characterizing the OAE 2. This enables the precise distribution of larger benthic foraminifers and their biotic response to paleoenvironmental changes to be characterized during this event. At Axaxacualco, oligotrophic conditions prevailed during the δ13C positive excursion in the distal part of the carbonate platform. In the more proximal part, at Barranca del Cañon, OAE 2 impact was more significant and is marked by thick laminated microbialite deposition, indicating mesotrophic conditions. Low phosphorus and trace-element contents confirm the persistence of oligotrophic to mesotrophic conditions throughout OAE 2 in the Central Mexico carbonate platform despite the proximity of the Caribbean-Colombian oceanic plateau. Before the δ13C positive excursion, which characterizes the OAE 2, the microfauna assemblage was well diversified, including corals, rudists, and large benthic foraminifera (Pseudorhapydionina chiapanensis, Pseudorhapydionina dubia, Cuneolina parva, Dicyclina sp., Chrysalidina gradata, and large miliolids). During the δ13C positive excursion, significant biotic changes occurred, with increasing dominance of organisms adapted to high-stress conditions. Endobenthic assemblages such as Nezzazatinella sp. and Nezzazata sp. were still present. The green symbiotic benthic foraminifera nearly disappeared, except C. parva and Dicyclina sp. During the basal Turonian, the carbonate platform returned to a more open and oxygenated environment, with the reappearance of pre-OAE microfauna, but without the large benthic foraminifera, which did not survive. The definitive drowning of the Guerrero-Morelos carbonate platform took place after the early Turonian, well above the end of the δ13C shift. The deposition of black shale and turbidites, which indicate deeper, anoxic environments, precluded large benthic foraminifera reestablishment. Correlation with the pelagic environments of the Eastbourne section (UK) reveals a synchronicity of biotic responses between basin and platform environments. Low-oxygen conditions are marked by multiple blooms of Heterohelix species in the basin, corresponding to an assemblage dominated by ?Decastronema, Thaumatoporella, and Istriloculina on the carbonate platforms.
Association between area deprivation and major depressive disorder in British men and women: a cohort study
Authors: Remes Olivia , Lafortune Louise , Wainwright Nick , Surtees Paul , Khaw Kay-Tee , Brayne Carol 
Published: November 2019

ObjectiveStudies have shown area-level deprivation can increase the risk for mental disorders over and above individual-level circumstances, such as education and social class. The objective of this study is to determine whether area deprivation is associated with major depressive disorder (MDD) in British women and men separately while adjusting for individual-level factors.DesignLarge, population study.SettingUK population-based cohort.Participants30 445 people from the general population aged 40 years and older and living in England consented to participate at study baseline, and of these, over 20 000 participants completed a structured Health and Life Experiences Questionnaire used to capture MDD. Area deprivation was measured in 1991 using Census data, and current MDD was assessed in 1996–2000. 8236 men and 10 335 women had complete data on all covariates.Primary outcome measureMDD identified according to the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV).ResultsIn this study, 3.3% (339/10 335) of women and 2.1% (177/8236) of men had MDD. Men living in the most deprived areas were 51% more likely to have depression than those living in areas that were not deprived (OR=1.51, 95% CI 1.01 to 2.24; p=0.043), but the association between deprivation and MDD was not statistically significant in women (OR=1.24, 95% CI 0.93 to 1.65; p=0.143).ConclusionThis study shows that the residential environment differentially affects men and women, and this needs to be taken into account by mental health policy-makers. Knowing that men living in deprived conditions are at high risk for having depression helps inform targeted prevention and intervention programmes.
Social capital and the health of left-behind older adults in rural China: a cross-sectional study
Authors: Ke Yan , Jiang Junfeng , Chen Yu 
Published: November 2019

ObjectiveTo examine the association between social capital and the health of male and female left-behind older adults in rural China.Study designThis cross-sectional study among the left-behind older adults aged 60 and older and with all their children working outside of Hubei, Shaanxi and Guangdong provinces in China was conducted in 2017–2018. A total of 1106 questionnaires were collected (participation rate=100.0%), and questionnaires from 1016 participants were used (effective rate=91.9%).MethodsAn ordinary least squares model was used to evaluate the association between social capital and health. Social capital included family trust, friend/neighbour trust, stranger trust, social participation, and network size and density. Health outcomes included basic and instrumental activities of daily living (BADL and IADL) and depression.ResultsElevated family trust, friend/neighbour trust, stranger trust, high-level participation and middle-level network density were associated with reduced depression (b=−3.23, p<0.001; b=−0.41, p<0.001; b=−0.76, p<0.01; b=−1.04, p<0.05; b=−0.74, p<0.05, respectively). High-level participation and network density were also associated with elevated BADL (b=0.16, p<0.05; b=0.24, p<0.05, respectively). Elevated family trust (b=−2.86, p<0.05 in men; b=−3.86, p<0.001 in women), stranger trust (b=−0.68, p<0.05 in men; b=−0.80, p<0.05 in women) and high-level participation (b=−0.92, p<0.05 in men; b=−1.22, p<0.01 in women) were associated with reduced depression in both sexes. By contrast, elevated friend/neighbour trust was associated with reduced depression (b=−0.56, p<0.001) in women, high-level participation was associated with elevated BADL (b=0.19, p<0.05) and IADL (b=0.43, p<0.05) in men, and high-level network density was associated with elevated BADL (b=0.44, p<0.05) and IADL (b=0.57, p<0.05) and reduced depression (b=−1.05, p<0.05) in women.ConclusionsSocial capital is closely related to left-behind older adults’ health in rural China. More attention should be paid to increasing the stock of social capital in this special population, with a particular focus on the sex disparity.
Urban scaling of health outcomes: a protocol for a scoping review
Authors: McCulley Edwin M , Mullachery Pricila , Rodriguez Daniel , Diez Roux Ana V , Bilal Usama 
Published: November 2019

IntroductionWith most of the world’s population living in urban areas, it is important to understand the health effects of city living. Precise descriptions of the relations of city size and growth with population health metrics have not been systematically described. Describing these relationships can provide clues regarding the factors driving differences in health across cities.ObjectiveThe goal of this scoping review is to map the existing evidence regarding the scaling properties of health outcomes, with a special emphasis on city size and growth.Method and analysisWe will conduct this scoping review based on a structured search of a combination of keywords for the exposures that aim to capture the population growth and size of cities along with degree of urbanisation, for health-related outcomes regardless of their type (incidence or prevalence of diseases and injuries and mortality). We will search the MEDLINE and Latin American & Caribbean Health Sciences Literature databases from inception for studies in English, Spanish or Portuguese and perform manual searches of references and citations in the included studies. The search will be conducted from April 2019 to September 2019. We will report results using the PRISMA-ScR guidelines. This review aims to inform future research on the role of increasing levels of urbanisation on health outcomes, provide clues into what city level factors may drive patterns of urban health and lead to the design and implementation of policies that promote sustainable growth and improved health.Ethics and disseminationThis review will not collect any primary data and will rely on published articles. The findings of this review will be published in a peer-reviewed scientific journal.