bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Elemental Technologies for Seafloor Mineral Processing of Seafloor Massive Sulfides
Authors: Nakajima Yasuharu , Yamamoto Joji , Takahashi Tomoko , Thornton Blair , Yamabe Yuta , Dodbiba Gjergj , Fujita Toyohisa 
Published: November 2019

Abstract
Seafloor Massive Sulfides have been expected to be future mineral resources. The grade of valuable metallic elements in ores of Seafloor Massive Sulfides is usually small percentage. If valuable minerals can be extracted from the ores on deep seafloor, the total mining cost can be reduced significantly. The authors proposed Seafloor Mineral Processing, where ores are to be ground into fine particles and separated into concentrates and tailings on seafloor. The Seafloor Mineral Processing system consists of processing units for unit operations such as grinding and separation. To investigate the applicability of flotation, which is a method to separate ore particles by using the difference in wettability of minerals, to the separation unit, measurements of contact angles of sulfide minerals at high pressures were carried out. The results suggested that the contact angles of the minerals would have relationships with pressure in depending on the kind of minerals and solutions. In addition, applying Laser-Induced breakdown Spectroscopy (LIBS), an optical method for elemental analysis, to measurement of metal grade of ore particles handled as slurry in the processing units was also investigated. Signals assigned to copper, zinc, and lead were successfully detected in the spectra obtained from ore particles in slurry flow.
Experimental Study on Ultimate Strength of Thin-Walled Square Tube Under Axial Compression
Authors: Zhou Hanwei , Zhu Ling , Zhang Shengming , Yu T. X. 
Published: November 2019

Abstract
There are many welded thin-walled square tube structures in ship structures. At present, researchers are mainly involved in axial compressive ultimate strength of square tubes with large aspect ratios. However, the study of square tubes with small aspect ratios on ultimate strength capacity have seldom been conducted. In order to study the ultimate strength capacity of thin-walled square tubes with small aspect ratio under axial compression, three welded thin-walled square tubes with different slenderness ratios were manufactured and studied in this paper. The ultimate strength of those models under axial compression were obtained experimentally. The experimental results were compared with numerical results performed by ABAQUS. The influence of slenderness ratios on the axial compressive ultimate strength of thin-walled square tubes is analyzed, and a feasible modelling of finite element method is proposed.
REDWIN Foundation Models for Integrated Dynamic Analyses of Offshore Wind Turbines
Authors: Page Ana M. , Norén-Cosgriff Karin , Skau Kristoffer S. , Kaynia Amir M. 
Published: November 2019

Abstract
Due to the complex nature of the loads on Offshore Wind Turbines (OWTs), accurate and optimized design of these structures require integrated simulation tools that can properly capture the various structural interactions governing the response. Considerable progress has been made in recent years on developing proper models for coupled aerodynamic and hydrodynamic loads together with advanced control systems for turbines. These efforts have resulted in a suite of aero-servo-hydro-elastic numerical simulation codes available to the industry. However, proper foundation models have been lagging behind in these tools despite availability of various advanced nonlinear models for foundations in general. This has led to uneconomical design of OWTs that have consistently failed to reproduce the measured natural frequencies and can negatively affect the design and structural performance of OWTs.
This paper presents a library of recently developed foundation models based on the theory of plasticity together with their verification against large-scale field test data. These models are cast in the framework of macro-elements that represent the nonlinear response of the soil-foundation system due to arbitrary coupled loads at the seabed. The paper also presents results of the numerical simulations of the dynamic response of a monopile-based OWT in the North Sea using an aero-servo-hydro-elastic code and comparison with the data collected from one of the instrumented OWTs in the field. It is further presented how the characteristics of the measured dynamic response change with loading over a long period and the way the response characteristics relate to the basic features of the developed models.
Study of the Relationship Between Oriented Downhole Dynamic Weight on Bit and Drilling Parameters in Coring Isotropic Natural and Synthetic Rocks
Authors: Abugharara Abdelsalam N. , Molgaard John , Hurich Charles A. , Butt Stephen D. 
Published: November 2019

Abstract
Coring natural rocks (granite) and synthetic rocks (rock like material, RLM) using diamond impregnated coring bit was performed by A rigid coring system. RLM and granite were previously tested to be isotropic rocks by the author [1, 2, 3, 4] A baseline procedure was developed for isotropic rock characterization [2] and this work is to contribute to the developed baseline procedure by considering downhole dynamic weight on bit (DDWOB). The drilling parameters involved in the analysis included rate of penetration (ROP) depth of cut (DOC), rpm, and torque. All parameters were studied as a function of DDWOB at 300 and 600 input rpm. A fully instrumented laboratory scale rotary drilling rig was used with 5 liter/minute water flow rate. Samples were first cored in 47.6 mm diameter in the desired orientations. Samples of granite were cored in two perpendicular directions (vertical and horizontal) and samples of RLM were cored in three directions including vertical, oblique, and horizontal. The coring experiments were performed using 25.4 mm diamond impregnated coring bit. At each input rpm and at each applied static weight, multiple coring runs were repeated and then averaged; therefore, each point of the displayed data was averaged of at least three repeated experiments at the same inputs. DDWOB was recorded by a load cell fixed beneath the sample holder and connected to a Data Acquisition System that records at 1000 HZ sampling rate. Several sensors were used to record the required data, including operational rotary speed, advancement of drill bit for ROP calculation, and motor current for torque measurement. Results showed similar trends in different orientations at the same inputs demonstrating RLM and granite isotropy. The results also showed the influence of DDWOB on ROP, DOC, rpm, and torque (TRQ) expanding the baseline procedure through considering DDWOB for isotropic rock characterization.
Ship As a Wave Buoy: Using Simulated Data to Train Neural Networks for Real Time Estimation of Relative Wave Direction
Authors: Mak Bart , Düz Bülent 
Published: November 2019

Abstract
Being able to give real time on-board advice, without depending on extensive sets of measured data, is the ultimate goal of the digital twin concept. Ideally, the models used in a digital twin only rely on current in-service data, although they have been built using simulated and possibly some measured data. Working with just the 6-DOF motions of a ship, can the local sea state reliably be estimated using the digital twin concept? Does a general model exist to do so, without the need to measure or simulate the particular ship?
In this paper, we discuss how simulations of an advancing ship, subjected to various sea states, can be used to estimate the relative wave direction from in-service motion measurements of the corresponding ship. Various types of neural networks are used and evaluated with simulated data and measured data. In order to study the generalization power of the neural networks, a range of ships has been simulated, with varying lengths, drafts and geometries. Neural networks have been trained on selections of the ships in this extended training set and evaluated on the remaining ships.
Results show that the developed neural networks give a remarkable performance in simulation data. Furthermore, generalization over geometry is very good, opening the door to train a general model for estimating sea state characteristics. Using the same model for in-service measurements does not perform well enough yet and further research is required. The paper will include discussion on possible causes for this performance gap and some promising ideas for future work.
Force Dynamics and Stationkeeping Costs for Multiline Anchor Systems in Floating Wind Farms With Different Spatial Parameters
Authors: Fontana Casey , Arwade Sanjay , DeGroot Don , Hallowell Spencer , Aubeny Charles , Diaz Brian , Landon Melissa , Ozmutlu Senol , Myers Andrew 
Published: November 2019

Abstract
While the offshore wind industry has shown a steady trend towards floating turbines, costs of these systems remain high. A multiline anchor concept may significantly reduce the high cost of floating wind, in which floating turbines share anchors. This work investigates the potential cost benefit of implementing a multiline anchor system relative to the conventional single-line anchor system over a range of spatial parameters. The OC4 DeepCwind semisubmersible platform is used to design catenary mooring systems for different water depths and turbine spacings. In all cases, the maximum anchor force in the 3-line anchor system is less than or equal to that of the single-line anchor system. Cost models for the mooring lines, anchors, installation and geotechnical site investigation are presented and discussed. In a 100-turbine farm, the multiline anchor system results in a 9–19% reduction in stationkeeping costs, with high and low estimates for the cost models additionally included. Larger reductions in the combined line and anchor cost result from mooring system configurations with smaller ratios of water depth to turbine spacing. Due to perimeter effects in the multiline configuration, larger cost reductions can be achieved for larger farm sizes.
Extreme Load Computational Fluid Dynamics Analysis and Verification for a Multibody Wave Energy Converter
Authors: van Rij Jennifer , Yu Yi-Hsiang , McCall Alan , Coe Ryan G. 
Published: November 2019

Abstract
A wave energy converter (WEC) must be designed to survive the extreme sea states that it will be subject to throughout its lifetime. Although there are many analysis methods and codes available to accomplish this, there are currently several engineering challenges to WEC survival design. Foremost, the computational design approach will typically involve a trade-off between accuracy and computational efficiency. Additionally, most computational fluid dynamics (CFD) codes are not ideally suited to modeling extreme events for WECs with multibody dynamics, power-take-off systems, and mooring systems. Finally, although WEC design standards and CFD guidelines are emerging, with the current immaturity of the WEC industry, they are not yet well established. In this study, loads on a 1:35-scale, moored, multibody WEC are evaluated with CFD. The CFD results are compared with results obtained from a computationally efficient, midfidelity model based on linearized potential flow hydrodynamics. For these model verification comparisons, both operational and survival configurations are considered. The extreme load results obtained, using both codes, indicate that the survival configuration successfully sheds loads during extreme sea states. It is also found that WEC-Sim, when appropriately applied, can provide reasonable load results, at a fraction of the computational expense of CFD. However, for the more extreme sea states, and for higher-order effects not included in the WEC-Sim model, the linear-based results have significant errors in comparison to the CFD-based results, and should be used judiciously.
Use of Tracer Particles for Tracking Fluid Interfaces in Primary Cementing
Authors: Taheri Amir , Ytrehus Jan David , Taghipour Ali , Lund Bjørnar , Lavrov Alexandre , Torsæter Malin 
Published: November 2019

Abstract
In this study, a new approach for detailed tracking of the interface between well fluid and cement by using particles is investigated. This can improve the quality of annular cementing of CO2 wells and thus the storage safety. For this purpose, the displacement mechanisms of Newtonian and non-Newtonian fluids in the annulus of vertical and inclined wells is investigated by using an experimental set-up with an eccentric annular geometry and by finite element analysis of an equivalent model with COMSOL Multiphysics solver. For more efficient displacement, the displacing fluid has a higher density than the displaced fluid, and the intermediate-buoyancy particles that reside at the interface between successive fluids are introduced into the models. Such particles must overcome strong secondary flows in order to travel with the interface.
Particle motions are investigated in different experimental and numerical models, and their effectiveness is investigated. The experimental results confirm that while the particles with a size of 425–500 um are unable to overcome the secondary flows in eccentric vertical models and track the interface, they can be useful for tracking the interface between two fluids in an eccentric model with a small inclination to the narrow side. CFD analysis investigates this behavior with more details and shows the effects of some parameters on the particle motions.
Application of Machine Learning Techniques As a Means of Mooring Integrity Monitoring
Authors: Gumley Jonathan M. , Marcollo Hayden , Wales Stuart , Potts Andrew E. , Carra Christopher J. 
Published: November 2019

Abstract
There is growing importance in the offshore floating production sector to develop reliable and robust means of continuously monitoring the integrity of mooring systems for FPSOs and FPUs, particularly in light of the upcoming introduction of API-RP-2MIM. Here, the limitations of the current range of monitoring techniques are discussed, including well established technologies such as load cells, sonar, or visual inspection, within the context of the growing mainstream acceptance of data science and machine learning. Due to the large fleet of floating production platforms currently in service, there is a need for a readily deployable solution that can be retrofitted to existing platforms to passively monitor the performance of floating assets on their moorings, for which machine learning based systems have particular advantages.
An earlier investigation conducted in 2016 on a shallow water, single point moored FPSO employed host facility data from in-service field measurements before and after a single mooring line failure event. This paper presents how the same machine learning techniques were applied to a deep water, semi taut, spread moored system where there was no host facility data available, therefore requiring a calibrated hydrodynamic numerical model to be used as the basis for the training data set.
The machine learning techniques applied to both real and synthetically generated data were successful in replicating the response of the original system, even with the latter subjected to different variations of artificial noise. Furthermore, utilizing a probability-based approach, it was demonstrated that replicating the response of the underlying system was a powerful technique for predicting changes in the mooring system.
Crack Growth due to Flow Mixing
Authors: Hannink M. H. C. , Blom F. J. 
Published: November 2019

Abstract
Turbulent mixing of hot and cold flows can lead to thermal fatigue of piping systems. Especially in primary pipework of nuclear power plants this is an important, safety related issue. Because the frequencies of the involved temperature fluctuations are generally too high to be detected well by common plant instrumentation, accurate numerical simulations are indispensable for a proper fatigue assessment. In this paper, fatigue crack growth analyses are presented for turbulent mixing in a T-junction. The temperatures in the fluid and the pipe were calculated by large eddy simulations with conjugate heat transfer, and the resulting stresses in the pipe by the finite element method. The stresses in the pipe wall have subsequently been used as input for crack growth analyses, which were performed according to ASME Boiler and Pressure Vessel Code, Section XI (2017). The time to a through-wall crack has been calculated for different temperature differences between the hot and cold flows. The analyses presented in this paper have been performed in preparation for the analyses of the EU project ATLAS+. In that project similar analyses will be performed on a different configuration.
Leakage of a High Temperature and High Pressure Flange Metal Gasket due to its Ratcheting in Alternating Pours of Rain
Authors: Chen Yanan , Wang Jianbo , Yu Chulin , Gao Bingjun 
Published: November 2019

Abstract
In the high pressure ethylene polymerization process, pipes transmitting reaction product are often bolt-flange connected with metal gaskets which demands high tightness. However ethylene and polyethylene was found leaking from a flange connection in the pipe out of a polymerization kettle after several pours of rain, which leads to an emergency shutdown. A finite element model was worked out to simulate the ratcheting of the metal gasket during the on and off rains by keeping the temperature of the pipe, flange, and gasket as 270°C, but changing the temperature of bolts from higher temperature 270°C to a lower temperature cyclically. Elastic and perfect plastic model was conservatively employed in the ratcheting analysis. It is found that gasket plastic strains accumulate with the bolt temperature drop cycles. The higher the bolt temperature drop, the more plastic strain accumulation. Consequently, the contact pressure between the flange and the gasket reduces with the bolt temperature cycles. The higher the temperature drop, the less the flange connection tightness. It reveals that bolt temperature drop below 155°C does not destroy the flange connection tightness with a gasket parameter 3.0. When temperature drops are above 155°C, temperature cycles to destroy the flange connection tightness decrease with temperature drops, namely the higher the temperature drop, the less temperature cycles needed to destroy the flange connection tightness. A margin line has been worked out to correlate the bolt temperature drops and cycles to the gasket leakage.
The Optimization Design of Storage Efficiency and Structural Analysis for the 3 Cubic Meter Radioactive Waste Container
Authors: Shen Yu-Yu , Lin Hsien-Chou , Chou Hsoung-Wei 
Published: November 2019

Abstract
Because the Taiwan domestic boiling water reactor nuclear power plant is under shutdown and going to be decommissioned, the development of radioactive waste container used for containing the radioactive waste from nuclear facility decommissioning and dismantling is a critical issue in recent years. The main purpose of this study is to design a metal container which can provide the highest storage efficiency for the low level radioactive waste, and ensure the structure meeting the safety requirements of related regulations. This paper first introduces the related regulations for the container in Taiwan. To determine the optimal storage efficiency of the container, the shielding analyses were performed by varying dimensions of 3 cubic meter containers to select the best one, and conduct the structural analyses. Then, a series of structural analyses for operational conditions such as static standstill analysis, lifting test and stacking test with full load were performed, as well as the drop impact analysis, to ensure the container structure meeting the safety requirements of regulations. Present work can provide design information of the development of radioactive waste container for decommissioned nuclear facility in Taiwan.
Proposed Modifications to API 579 Part 3 Brittle Fracture Screening Procedures
Authors: Macejko Brian R. , Kummari Seetha Ramudu , Prueter Phillip E. 
Published: November 2019

Abstract
Significant inconsistencies and inadequacies exist in the current brittle fracture screening procedures in the 2016 edition of API 579-1/ASME FFS-1, Fitness-For-Service (API 579). Results from an evaluation completed using the current published guidance could prove unsafe in some instances. The ASME/API Joint Committee on Fitness-For-Service (FFS) recently initiated a project to rewrite API 579 Part 3, Assessment of Existing Equipment for Brittle Fracture. The intent of the project is to establish new Level 1 and Level 2 evaluation procedures and acceptance criteria developed using state-of-the-art fracture mechanics consistent with the Part 9 Failure Assessment Diagram (FAD) approach, currently employed in Level 3 FFS evaluations. This paper will provide a comprehensive summary of deficiencies and concerns with current published methods for evaluating susceptibility of pressure equipment to potential brittle fracture failures. Additionally, the paper will provide an overview of the methodology employed in the recently proposed procedure modifications for Part 3 of API 579 to mitigate the current deficiencies.
A New Design Method for Axially Loaded Thin-Walled Cylindrical Shells Based on Elasto-Plastic Buckling Analysis
Authors: Jiao Peng , Chen Zhiping , Ma He 
Published: November 2019

Abstract
In engineering, thin-walled cylindrical shells subjected to axial compression load are very sensitive to geometric imperfections and are prone to buckling. However, how to reasonably take into account the influence of geometric imperfections on the load carrying capacity of thin-walled cylindrical shells is always the bottleneck of light-weight design of these structures. In this paper, four perturbation load approach (4PLA) is adopted to consider the influence of geometric imperfections. By judging the potential buckling status of cylindrical shells, a new improved design method based on 4PLA for thin-walled cylindrical shells is proposed, in which the influence of radius-to-thickness ratio, length-to-radius ratio, Young’s modulus and material yield strength are systematically considered. Correspondingly, the buckling tests for two steel cylindrical shells with the same geometric and material parameters are conducted. Compared with the experimental results and other test results in open literatures, the superiority and safety of proposed method for the preliminary design of thin-walled cylindrical shells are validated.
Fracture Toughness Testing of an Overmatched Pipe Girth Weld Using Clamped SE(T) Specimens
Authors: Ferreira Claudinei , Burgos Diego F. S. , Ruggieri Claudio 
Published: November 2019

Abstract
This work presents an investigation of the ductile tearing properties for a girth weld made of an ASTM A106 Gr C steel using the SMAW welding process with a low hydrogen E7018 electrode thereby resulting in a weld with high strength overmatching with respect to the base material. Testing of the pipe girth welds employed side-grooved, clamped SE(T) specimens with a weld centerline notch to determine the crack growth resistance curves based upon the unloading compliance (UC) method using a single specimen technique. Recently developed compliance functions and η-factors applicable to weld centerline notched SE(T) specimens are introduced to determine crack growth resistance data from laboratory measurements of load-displacement records. While the UC procedure resulted in measured crack extensions for the tested specimens with weld centerline notch that underestimated the 9-point average crack extension, our preliminary results demonstrate the capability of the methodology in describing crack growth resistance behavior which serves as a basis for ductile tearing assessments in ECA procedures applicable to overmatched girth welds and similar structural components.