bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Optimization Algorithm on Parameters of an Empirical VIV Prediction Tool
Authors: Yin Decao , Wu Jie , Lie Halvor , Jin Jingzhe , Passano Elizabeth , Sævik Svein , Eidnes Solve , Grytoyr Guttorm , Tognarelli Michael A. , Andersen Torgrim , Igland Ragnar , Karunakaran Daniel , Gaskill Collin 
Published: October 2022

Abstract
Conventional vortex-induced vibration (VIV) prediction tools are semi-empirical, in other words, based on several empirical parameters extracted from model tests in laboratory. Generally, the lab tests are costly, include small scale test conditions and with a limited test matrix. The extracted empirical databases are not directly applicable to full-scale VIV predictions of various slender marine structures. Therefore, large safety factors have been used by industry for VIV prediction in the past decades.
To reduce the uncertainty (e.g. over-conservatism) related to semi-empirical VIV prediction tools, the NLPQL algorithm for parameter optimization of a semi-empirical time-domain prediction tool has been investigated.
This methodology was demonstrated on pure cross-flow VIV prediction in an earlier study. It was shown that by setting appropriate constraints and cost functions of the optimization algorithm, this method is feasible to improve the VIV prediction accuracy. In this study, the NLPQL optimization algorithm was applied for combined cross-flow and in-line VIV predictions using time domain numerical model. Selected cases from field measurements representing multi-fidelity data were used to validate and verify the method.
A Life-Cycle Cost Framework for Onboard Emission Reduction Technologies: The Case of the Flapping-Foil Thruster Propulsion Innovation
Authors: Ventikos Nikolaos P. , Perera Lokukaluge P. , Sotiralis Panagiotis , Annetis Emmanouil , Stamatopoulou Eirini V. 
Published: October 2022

Abstract
To deal with the decarbonization challenge in an efficient way in terms of cost-effectiveness, reliability and feasibility for newbuilding and retrofit solutions in maritime industry, Seatech H2020 project develops a flapping-foil thruster propulsion innovation, together with a dual-fuel engine innovation to increase fuel efficiency and reduce emissions. The focus of this study is on the foil thruster, which is arranged at the bow and slightly in front of the ship, and it utilises the energy from wave-induced motions by converting it into thrust. For such innovations, a clear picture of its economic impacts facilitates their adoption. Thus, to deal with the economic aspects, from a life cycle perspective, the paper introduces a life-cycle cost analysis (LCCA) framework, which includes all four phases of the system’s life cycle; construction, operation, maintenance and end-of-life. In the context of the developed framework, the initial challenge for the LCCA exercise is to fully define the design details of the system, which will facilitate the cost approximation, mainly for construction, maintenance and end-of-life phases. The results from the materialisation of the LCCA provide significant insight with respect to the lifecycle costs and may support the decision-making process for newbuilding and retrofitting investments.
Statistical Variation Of The 3-Hour Maximum Crest Height in a Survival Sea State
Authors: Bunnik Tim , Scharnke Jule 
Published: October 2022

Abstract
Due to the random nature of extreme waves, wave impacts follow a highly stochastic pattern. To reduce the statistical uncertainties that are naturally arising in estimates of design loads related to extreme waves, sufficient data must be gathered. The first step in a design load analysis is the realization of a set of realistic (typically 3-hour) waves which is large enough to describe the randomness in the impact in sufficient detail, such that the probability of exceedance of the maximum 3-hour load levels can be predicted accurately. In this paper we will investigate if Computational Fluid Dynamics (CFD) is capable of predicting realistic random 3-hour extreme waves. Since the maximum 3-hour load is driven by the highest and steepest waves we will look into the distribution of the maximum 3-hour crest height and the corresponding wave steepness of these events. A comparison is made with wave flume measurements in which 100 random realizations of an extreme wave (Hs = 16.7m, Tp = 15.9s) with a 10,000-year return period were generated and measured.
Hydroelastic Simulation of Breaking Wave Impact on a Flexible Coastal Seawall
Authors: Li Yuzhu , Hu Zhengyu , Huang Luofeng 
Published: October 2022

Abstract
The impact of breaking waves on an elastic vertical wall is investigated with a fully-coupled numerical model. The waves breaking on a 1:10 sloped bed is simulated with the computational fluid dynamics (CFD) approach with the stabilized k-ω model for turbulence closure. The deformations and stresses in the elastic vertical wall are investigated with the computational solid mechanics (CSM) approach. The CFD and CSM approaches are fully-coupled in the finite-volume-method-based OpenFOAM framework. The present approach is verified against an existing study of the interaction between non-breaking solitary waves and an elastic vertical wall. Good agreement is obtained. Then the breaking waves are simulated and their interaction with the elastic vertical wall is investigated. It is found that breaking waves can cause strong deformation and vibration of the elastic seawall. The oscillation frequency of the seawall is four times the wave frequency.
Design and Global Performance of a Semi-Submersible Floating Offshore Wind Turbine System
Authors: Shi Xiaohua , Cheng Yongming , Shen Yang , Shou Chunhui , Chu Zhuyu , Lin Gan 
Published: October 2022

Abstract
Offshore wind turbines are a leading renewable energy technology with significant potential to support the drive for a low-carbon economy. As the availability of shallow water sites declines, floating offshore wind turbine (FOWT) technologies can play a leading role in accessing deep water sites. This paper investigates design and global performance of a semi-submersible floating offshore wind turbine system.
Existing design concepts of floating support structures and station keeping systems for FOWT’s are mostly developed based on experience from the offshore oil and gas industry, which has witnessed almost 70 years of designing and operating numerous floating offshore structures. This paper first introduces a new semi-submersible FOWT system developed by the authors for the application in South China Sea. The system consists of 8MW wind turbine, supporting tower, semi-submersible platform structure, station keeping mooring lines, and dynamic cable. The principal dimensions of the platform and ballast setting are iteratively designed for the better global performance in terms of response amplitude operator. The FOWT system also covers the layout of mooring lines and the configuration of dynamic cable. The semi-submersible FOWT system is designed to meet the requirement for natural periods recommended by the guidance notes from ABS.
The time domain fully coupled aero-hydro-servo-elastic response of the floating wind turbine is investigated by using the FEA program of OrcaFlex. The turbine takes the form of a conventional three-bladed rotor, with variable-speed and variable blade-pitch control capabilities. The turbine object in OrcaFlex is used to model the generator, gearbox, hub, blades and associated control systems. The environmental conditions in South China Sea are used in the dynamic analysis. The load case matrix covers 1-yr operating, 10-yr, and 100-yr extreme conditions. The time history of generator power is presented for the illustration of the regulation facilitated by the blade controller. The results include generator power, vessel offset, heave motion, heel angle, and maximum tension of mooring lines. For the 100-yr tropical environmental condition, the wind turbine is parked. The air gap especially at the tip of blades is examined for the extreme parked condition.
This paper finally summarizes the findings from the design and global performance of the semi-submersible floating offshore wind turbine system.
Numerical Simulation of Bimodal Wave Spectrum Based on Viscous CFD Method
Authors: Chen Jingyao , Liu Liwei , Wang Xianzhou , Li Jianxin , Yao Xi 
Published: October 2022

Abstract
Sea wave spectra play an important role in the design of marine vehicle and off-shore structures. Most of the available studies for seakeeping performance of marine vehicle have been concentrated on analyzing the wave spectra generated by local wind due to its simplicity as well as inadequacy of measurements. However, simultaneous presence of swell always changes the model of wave spectrum and affecting offshore structures design seakeeping safety. In this study, the Ochi-Hubble spectrum, which is a typical six-parameter (based on the data set from south China sea) bimodal spectrum, is applied to model the mixed long-crest wave composed of wind-sea and swell components. Based on an in-house computational fluid dynamics (CFD) solver, a numerical wave tank is developed and the wave generating method by defining the velocity inlet boundary condition is used to simulate the mixed wave composed of wind-sea and swell. The level-set method is applied to capture the free surface during the numerical simulation. Verification and validation works are carried out to estimate the numerical errors and uncertainties for the mixed wave generation. Verification work includes grid and time-step convergence studies, where the proper time-step and grid can be determined. For the validation study, the numerical results are compared with the theoretical results, with respect to the time series behavior and spectrum characteristic. The comparisons show that the differences of the typical parameters between the CFD and theoretical results are all less than 3%, which indicate that the CFD method simulates the mixed wave accurately.
Hydrodynamic Analysis in Marine Operations: A Preprocessing and Postprocessing Tool
Authors: Gullaksen Joannes 
Published: October 2022

Abstract
A pre- & post-processor for modelling and analysis of marine operations to support hydrodynamic subsea installation analysis is presented in this paper. The pre-processor is automating the input model for static analysis, that also includes preliminary estimates of load effects as basis for product configuration and input parameters to dynamic analysis models, including product specific capacities and limit state criteria directly related to installation operation. Subsea installation operations will normally be weather restricted operations demanding a thorough evaluation of relevant environmental conditions. Short-term wave conditions are described by a stochastic method using wave spectra, or the deterministic design wave method. Statistical distributions are used to describe long-term and extreme value conditions, or scatter diagrams for governing sea state parameters. Joint wave-current distributions of parameters and corresponding surfaces for given exceedance probability levels are considered. The analyses establish relevant installation parameters required in order to carry out the installation operations in a safe manner. Static analysis is also used for curve stability analysis, on-bottom stability analysis, recovery analysis, J-tube pull-in analysis, tie-in analysis and sensitivity analysis. The post-processor is used to display and review the static and dynamic analysis results, including compliance with the given limit state criteria under the relevant limiting weather conditions of each operation. This also includes easy comprehension of data supported by tools that provides the ability to easily view appropriate results quantities on all model objects. Important for a fast analysis turnaround is the ability to process the data and support the user in getting the necessary information to understand the model’s hydrodynamic behaviour.
A Comparison of Approaches for Modelling Walk-to-Work Gangway Access
Authors: Moverley Smith Ben , Middleditch Ben , Thies Philipp 
Published: October 2022

Abstract
The accessibility of offshore wind farms is a key parameter when considering the cost of the operations and maintenance (O&M) of wind farm assets. Indeed, the weather limits for accessing wind turbines is a critical input in many tools which seek to simulate and optimize O&M activities. To refine this input, numerical modelling has been performed previously to perform workability analyses for service operation vessels with motion compensated walk to work gangways. However, previous modelling effort has employed an implicit representation of a gangway, which does not consider the relative motion of gangway subcomponents. In this study, two different gangway representations are employed for a numerical simulation of a transfer procedure between a service operation vessel and an offshore turbine. Comparison of the limiting wave heights given by analysis of the implicit and explicit representation of the gangway shows a difference when considering waves incident toward the vessel from the foundation location, with much lower wave heights allowed by the complex representation. Applying this difference in operational wave heights to a case study location leads to a difference in overall site availability of over 9%. The implications of these findings on future accessibility analysis and foundation design are discussed.
GPU-Accelerated High-Order Spectral - OpenFOAM Coupled Model for Numerical Analysis of Ship Motion in Nonlinear Waves
Authors: My Ha Dao , Xin Lu , Quang Tuyen Le 
Published: October 2022

Abstract
The High-Order Spectral (HOS) has been a desirable method for studies of fully nonlinear wave propagation over very large areas. To handle a long-standing classical problem of surface waves-current-structure interaction, we introduce several major developments. We first extend HOS-based wave model to include a prescribed steady current. We then migrate the code to the GPU platform to speed-up the simulation. The GPU-accelerated HOS solver is then coupled with a CPU-based CFD multiphase solver in OpenFOAM to account for the FSI. The coupled solver is demonstrated for simulations wave-current interactions. Lastly, the near and far field coupling solver is applied to a simulation of the seakeeping response of a cruising ship hull in head wave condition.
Prediction and Benchmarking of a Nearly Horizontal Flowline Slug Flow
Authors: Mesa Jose D. , Gao Haijing , Constantinides Yiannis 
Published: October 2022

Abstract
In recent years the oil and gas industry has increased its attention to slugging flow-induced vibration challenges due to their effect in deep and shallow water assets operations. Risers, subsea pipelines and jumpers are checked to ensure that the predicted slugging events based on the well’s production life do not consume excessive fatigue capacity and provide a suitable design basis. For shallow water gas production wells, the fatigue generated due to slug events can be a governing case for pipeline and riser design. Due to the complexity of the internal-flow physics, numerical simulations are typically employed to predict the number of expected slug events and characteristics during the design phase.
One well-known limitation in commercial flow simulation packages is the prediction uncertainty for slug flows in risers and pipelines. The abrupt changes in the pipeline content density and asset configuration can promote the generation of slugs, increasing the probability of underpredicting the number of events through the asset service life and reducing the accuracy of the slug characteristics prediction. Furthermore, there is no standardized methodology for the slug analysis required in the industry or regulatory agencies.
This study documents the current limitations of the industry practices and state-of-the-art methods to predict slug flow that can affect operations and integrity of assets. The first industry flow-induced vibration experiments that couples the internal flow with its structural response are presented. The experimental data collected in this study on slugging characteristics are benchmarked against predictions from flow simulators to address the modeling uncertainties of slug characteristics. The benchmarking study further explains the multiphase model limitations and prediction bias for the slugging phenomenon in a pipeline.
Supplemental Material: Detrital glass in a Bering Sea sediment core yields a ca. 160 ka Marine Isotope Stage 6 age for Old Crow tephra
Authors: Reyes Alberto , Jensen Britta J.L. , al. et 
Published: October 2022

<p>Detailed sampling, analytical, age model, and machine learning methods and Data Sets S1 and S2 (electron microprobe and machine learning results). </p>
Synthesis and Chemoresistive Properties of Single-Layer MXene Ti2CTx
Authors: Simonenko E. P. , Simonenko N. P. , Nagornov I. A. , Simonenko T. L. , Gorobtsov Ph. Yu. , Mokrushin A. S. , Kuznetsov N. T. 
Published: October 2022

Abstract
As part of the study, we have developed a method for obtaining a single-layer Ti2CTx MXene by the interaction of Ti2AlC with a mixture of hydrochloric acid and sodium fluoride followed by delamination using a tetramethylammonium hydroxide solution and ultrasonic exposure. The obtained stable aqueous dispersion of Ti2CTx has been applied by microplotter printing onto a specialized sensor chip, which has been dried at a temperature of 150°C under reduced pressure. The coating has been studied using modern physicochemical methods of analysis. According to the data of X-ray spectral elemental microanalysis, the ratio n(Ti) : n(F + Cl) = 2 : (0.82–0.85), n(F) : n(Cl) ≈ 6 : 4; aluminum impurity does not exceed 1.5–2.0%. Data have been obtained on the local electrophysical properties of the Ti2CTx coating: on the value of the electron work function from the surface of the material, the distribution of charge carriers, and the capacitance gradient of the “probe tip–sample microregion” capacitor. For the first time, at an operating temperature of 30°C, extremely high chemoresistive responses of the Ti2CTx receptor layer to the content of 1 and 5% oxygen in nitrogen have been determined, which amounted to 8.6 and >276, respectively.
O uso indiscriminado de agrotóxicos na agricultura, seus impactos na saúde do trabalhador rural e a consequente responsabilidade civil no Brasil
Authors: Silva Thiago Henrique Costa , Moreira Ludmila Rodrigues Coimbra , Jordão Luciana Ramos , Silva Nara Rúbia Rodrigues do Nascimento , Rodrigues Valquíria Duarte Vieira 
Published: October 2022

Esta pesquisa buscou compreender os impactos gerados na saúde do trabalhador rural pelo uso indiscriminado de agrotóxicos e os desafios para a responsabilização no Brasil. Contrapôs-se o discurso produtivista, utilizado para ampliar cada vez mais a quantidade e variedade de agrotóxicos utilizados, e o discurso em torno da segurança e soberania alimentar e nutricional, que busca alternativas ao modelo produtivo hegemônico. Para tanto, com uma abordagem qualitativa guiada pela dialética, utilizaram-se pesquisas bibliográficas e documentais, além de análises indiretas de dados acerca do uso e da contaminação por agrotóxicos e análises jurisprudenciais acerca da responsabilidade civil decorrente de sua má utilização. Inferiu-se que há casos de responsabilização na jurisprudência brasileira, mas que, pela natureza do dano e pela dificuldade de estabelecer o nexo causal, ela ocorre em caráter excepcional. Como consequência, revelou-se a necessidade de avançar no estudo da responsabilidade e do risco da atividade, de maneira a proteger a saúde humana, em especial a do trabalhador rural, afetado diariamente pelos impactos dos insumos químicos que é obrigado ou, no mínimo, instado a manipular.
Testemunhos contra o nosso desaparecimento: Nan Goldin, a aids e a fotografia de intimidade
Authors: Gomes Priscyla Freitas 
Published: October 2022

O presente artigo apresenta uma iniciativa pouco difundida na historiografia das artes visuais. Uma mostra concebida pela fotógrafa estadunidense Nan Goldin, que vislumbrou num momento de exceção uma possibilidade de visibilizar os reflexos da epidemia na produção de diversos artistas. Em meio à epidemia da aids, em que o preconceito e as mortes consecutivas estabeleciam duros limites à atuação, Goldin mobilizou uma síntese de profunda delicadeza. Retomar esse exemplo, nesse contexto, abre uma série de paralelos históricos que permitem compreender especificidades e recorrências. Mais do que estabelecer uma espécie de prognóstico para caminhos futuros, o artigo estimula a encontrar em exemplos históricos formas de contato com o hoje.
Memoryless Optimality: Neurons Do Not Need Adaptation to Optimally Encode Stimuli With Arbitrarily Complex Statistics
Authors: Forkosh Oren 
Published: October 2022

Abstract
Our neurons seem capable of handling any type of data, regardless of its scale or statistical properties. In this letter, we suggest that optimal coding may occur at the single-neuron level without requiring memory, adaptation, or evolutionary-driven fit to the stimuli. We refer to a neural circuit as optimal if it maximizes the mutual information between its inputs and outputs. We show that often encountered differentiator neurons, or neurons that respond mainly to changes in the input, are capable of using all their information capacity when handling samples of any statistical distribution. We demonstrate this optimality using both analytical methods and simulations. In addition to demonstrating the simplicity and elegance of neural processing, this result might provide a way to improve the handling of data by artificial neural networks.
Unsupervised Domain Adaptation for Extra Features in the Target Domain Using Optimal Transport
Authors: Aritake Toshimitsu , Hino Hideitsu 
Published: October 2022

Abstract
Domain adaptation aims to transfer knowledge of labeled instances obtained from a source domain to a target domain to fill the gap between the domains. Most domain adaptation methods assume that the source and target domains have the same dimensionality. Methods that are applicable when the number of features is different in each domain have rarely been studied, especially when no label information is given for the test data obtained from the target domain. In this letter, it is assumed that common features exist in both domains and that extra (new additional) features are observed in the target domain; hence, the dimensionality of the target domain is higher than that of the source domain. To leverage the homogeneity of the common features, the adaptation between these source and target domains is formulated as an optimal transport (OT) problem. In addition, a learning bound in the target domain for the proposed OT-based method is derived. The proposed algorithm is validated using both simulated and real-world data.