bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimized U-OWC Wave Energy Converter in the Mediterranean Sea
Authors: Romolo Alessandra , Arena Felice
Published: September 2023

The REWEC3 (Resonant Wave Energy Converter – realization 3) is a fixed oscillating water column (OWC) wave energy converter (WEC) based on a U-shaped collector (for this reason namely also U-OWC) aimed to be incorporated in breakwaters. The device is composed by a chamber containing a water column in its lower part and an air pocket in its upper part. The air pocket is connected to the atmosphere via a duct hosting a self-rectifying air turbine. In addition, a REWEC3 includes a vertical U-shaped duct for connecting the water column to the open sea. The working principle of the system is quite simple: by the action of the incident waves, the water inside the U-shaped duct is subject to a reciprocating motion, which induces alternately a compression and an expansion of the air pocket. The pressure difference between the air pocket and the atmosphere is used to drive an air turbine coupled to an off-the-shelf electrical generator connected to the grid.

The main feature of the REWEC3 is the possibility of tuning the natural period of the water column in order to match a desired wave period through the size of the U-duct.

This paper aims to provide an optimized configuration of the U-OWC pneumatic chambers in order to maximize the air power available to a possible PTO for the wave energy conversion. For this purpose, two different REWEC3 configurations are analysed: A) with independent cells, that is the REWEC3/3 or U-OWC/3; B) with adjacent connecting cells, that is the REWEC3/2 or U-OWC/2. Finally, a critical analysis of the performances in both configurations will be presented.
FAT Pressure Impact on Residual Stress in Flexible Pipe Pressure Armours
Authors: Sautreuil Dorine , Deheeger Antoine , Wang Howard
Published: September 2023

The manufacturing of flexible pipes involves the spiralling of carbon steel material wires, with high permanent deformation where significant residual stresses could remain in the wire. These residual stresses directly impact the service life of the flexible pipe. By application of hydrostatic internal pressure during the Factory Acceptance Test (FAT), residual stresses can be released. These residual manufacturing stresses and the relaxation due to the FAT shall be considered for an accurate pressure armour service life prediction.

A recent study was conducted on a flexible pipe riser to quantify the reduction of residual stresses due to FAT process on pressure armour wires. The residual stresses have been measured using X-Ray Diffraction (XRD) approach, a non-destructive methodology appropriated for shaped areas, contrary to the Hole Drilling methods. Two samples were manufactured and used for measurements: one sample that had not undergone FAT and another that had undergone FAT. The measured values were then compared to identify the FAT pressure impact on the wire residual stresses.

This paper presents the residual stress measurements and the results analyses. It also discusses the pressure impact on the residual stresses on the flexible pipe pressure armour wires.
Numerical Analysis of the Effect of Multidirectional Load on the Bearing Capacity of Suction Bucket Foundation
Authors: Yan Bin , Zhu Wenxuan , Gao Bin , Ye Guanlin , Tian Yinghui
Published: September 2023

With the development of clean energy, the development of offshore wind and tidal energy is being emphasized. In deeper waters, shared anchored foundations are becoming the preferred form of foundation for future energy development. Multiple floating structures are simultaneously anchored by a single anchor foundation, thereby reducing the number of anchor foundations used and saving construction costs. The anchor and the seabed form a coupled system that needs to withstand various loads, including wind, waves, currents and their combined effects. Under wind and wave loads, a foundation can be loaded in one direction and unloaded in another due to the phase difference of multi-directional loads or failure of one anchor system, which can have a great impact on the normal operation of the foundation. In this paper, a suction bucket foundation is investigated as an anchor of shared anchor foundations. The effect of the magnitude of the loads in two different directions and the angle between them on the load carrying capacity was investigated. The finite element software named DBLEAVES-X with an advanced constitutive model was used in the research. According to the results, when the suction bucket foundation is subjected to multidirectional loading, its bearing capacity decreases, and the decrease is influenced by the angle between two different directional loads, the load level, and the relative density of the soil.
An Improved Total Interpretive Structural Modeling Method for Constructing Indicator Systems in Multi-Criteria Decision-Making Problems: The Case of Ship Design Evaluation and Selection
Authors: Chen Cheng , Zhang Xiangrui , Zhang Pei , Feng Feng , Sun Cong , Zhang Xiuyuan
Published: September 2023

The inherent complexity of large ships makes it challenging to construct appropriate indicator systems for evaluating and selecting optimal ship designs. Knowledge-based expert systems can be reasonable solutions. However, this problem needs more rationality and better operability, especially in complicated multi-criteria decision-making (MCDM) problems with numerous indicators and complex structures. This paper aims to present a universal methodological approach for constructing indicator systems in MCDM problems using an improved total interpretive structural modeling (TISM) method. The classical TISM method is extended under group decision-making settings and interval type-2 fuzzy sets (IT2FS) environment to deal with the uncertainties and variances in expert knowledge. To ensure the rationality and operability of indicator system construction, two novel cardinal and ordinal indices are proposed to quantify the degree of group consensus, and an interactive group consensus improvement algorithm is further developed to assist experts in reviewing their opinions to achieve acceptable group consensus. Finally, a case study of constructing a ship-equipment environmental suitability indicator system is examined to illustrate the feasibility and effectiveness of the proposed method, with the results indicating that the improved TISM method can deal with the uncertainties and variances in expert knowledge, promote rationality and operability in indicator system construction, and can be applied to numerous group decision-making problems.
Monopile-Supported Offshore Wind Turbine Ultimate Limit State Design Format From a Structural Reliability Point’ of View – Impact of Uncertainties in Loads and Strength on the Implied Safety Level
Authors: Amlashi Hadi
Published: September 2023

Offshore wind turbines are complex systems which are subjected to complicated loads and load effects. This will demand comprehensive numerical modelling of the structure for both loads and resistance. Design by direct analysis and first principles of hydrodynamic and aerodynamic loads and their effects on offshore wind turbine structure are hence preferred to limit the uncertainty in modelling and prediction. Therefore, it is important to account for the uncertainties in load effect (responses) and resistance modelling in relation to the current design value. This paper deals with the monopile-supported offshore wind turbine ultimate limit state design format. The effect of model uncertainty in loads and resistance on the safety level are studied. Differences in safety levels due to such uncertainties show that the implied safety level is not properly harmonized. Impact of bias and random uncertainty in calculation of wind and wave nonlinearities and the correlation between nonlinear prediction and statistical predictions of both wave and wind loads on the implied safety level should carefully be accounted for.
Development of Integrated Acoustic Communication and Positioning System for Operation of Autonomous Underwater Vehicles and a Sea Trial
Authors: Watanabe Yoshitaka , Kondo Satoshi , Meguro Koji , Shimura Takuya , Deguchi Mitsuyasu , Kida Yukihiro
Published: September 2023

An integrated acoustic communication and positioning system for the operation of autonomous underwater vehicles (AUVs) was developed, in which the acoustic communication function and positioning functions are integrated and the transmission timing of acoustic packets is controlled to efficiently use time and frequency resources. A chip scall atomic clock (CSAC) is equipped with the system and the systems on each vehicle are synchronized. The propagation time of the acoustic packet is then measured with one-way time (OWT) of flight and information of transmission time. In the integrated and synchronized mode, uplinks (ULs) from AUVs are periodically transmitted, and transmission timing of downlinks (DLs) from autonomous surface vehicle (ASV) is controlled to avoid collision of the ULs and DLs. A sea trial was conducted in a deep-sea area with a water depth of 1,100–1,150 meters. Four AUVs were simultaneously operated with an ASV for positioning and monitoring the AUVs using the developed acoustic system with the integrated and synchronized mode. The AUVs cruised for 2.5 hours near the seabed. The developed system worked well and the sea trial was successfully performed. The period of hull swing of the ASV was rapid owing to its small body and the Doppler effect was varied quickly; however, the acoustic communication was stable. Positioning and control of transmission timing was successfully achieved. On the other hand, an improvement in the accuracy of positioning is desired for operation in deep water areas.
Flexible Pipe Fatigue Life Evaluation Based on a Dynamic Full-Scale Test Considering a Preconditioning Corrosion Procedure
Authors: Brun Coser Tiago , Sulino de Negreiros Luiz Antonio , Carneiro Campello George , Duarte Radke Erik , Delwing Rosa Carolina , Fonseca De Souza Derek , Venturini Rodrigues Luiz Francisco , Renck Tiago Samuel , dos Reis Tagliari Mariana , Favaro Borges Marcelo
Published: September 2023

In this work, a systematic approach was adopted to evaluate the fatigue resistance of a flexible pipe with corroded tensile armour wires. A mid-scale test apparatus was developed to expose a short flexible pipe section to a controlled corrosive environment. After the exposure period, four-point bending fatigue tests were carried out using corroded tensile armour wire samples obtained from the preconditioned short flexible pipe sample. The results were compared with a reference SN curve and it was possible to observe the detrimental effect due to the preconditioning procedure. Parallel with the mid-scale test execution, a full-scale flexible pipe sample was preconditioned with the same corrosive environment used for the short sample. After 12 months, a dynamic tension-to-tension test was conducted and the fatigue damage imposed during the test was calculated. It was possible to observe a better correlation between the full-scale test result and the estimation done when the SN curves of pre-corroded armour wires was used. Even though further studies need to be carried out, current results show that the consideration of SN curves obtained from corroded tensile armour wires would increase reliability and accuracy in flexible pipe fatigue life assessments.
Identification of Interacting Free Spans in a Subsea Pipeline
Authors: Saraswat Rajil , Patil Palash , Ciecko Edward , Koul Parul
Published: September 2023

Free span in pipelines can occur intentionally either due to the seabed topography during laying, or it can be caused by scouring of the seabed during operation. A free span section can either be on its own which is known as ‘single span’ or multiple spans can be in close vicinity and form a ‘multi-span’. The unsupported section (free span) of the pipeline in presence of currents has a potential of causing vortex induced vibration (VIV). In such a scenario, the pipeline can vibrate along the flow direction (inline) or perpendicular to it (crossflow). This is detrimental to the pipeline especially to the welds, as this leads to the accumulation of fatigue damage leading to a reduction in fatigue life.

The recommended practice DNV-RP-F105 ‘Free Spanning Pipelines’ [1] lays out the methodology to assess fatigue in free-spanning pipelines. In a multi-span scenario, the spans in close vicinity may interact with each other. The morphological classification plot (release 2006 Figure 1-2) in the DNV-RP-F105 provides means to decide whether the span is interacting based on relative lengths of the spans and intermediate shoulder. In a recent update of the DNV-RP-F105 (2017), this classification plot was called out as inaccurate. Additional guidance was added describing an algorithm to assess whether a span is a single span or an interacting multi-span.

In this work the new guidance was used to classify the spans as isolated or interacting for an existing pipeline. The free spans were identified through a survey of the pipeline using multibeam echosounder and sidescan sonar. The multi-spans were identified from the free span listing. For each multi-span multiple finite element (FE) models were developed to compare the modal response of the multi-span against each span member. A comparison was also made with the morphological classification plot to check its validity.
Semi-Analytical Load Models Accounting for the Tilt and Motion of a Cylinder Impacted by a Plunging Breaking Wave
Authors: Renaud Paul , Hulin Florian , Batlle Martin Marc , Scolan Yves-Marie , Tassin Alan , Jacques Nicolas , Harris Jeffrey C. , Filipot Jean-François
Published: September 2023

This work is part of the DIMPACT project that addresses breaking-wave-induced loads on floating wind turbines. In this context, the hydrodynamic impact of a strong plunging breaking wave on a cylinder is studied using semi-analytical models, with a focus on the loads sensitivity to the cylinder tilt and wave-cylinder relative motion.

Two semi-analytical models are applied in a strip theory approach under the Froude-Krylov assumption. A numerical wave is generated using a Fully Nonlinear Potential Flow (FNPF) solver, whose free surface geometry and kinematics feed the semi-analytical models. Semi-analytical slamming loads are compared with force measurements collected in a wave flume for different pitch angles and surge speeds. The temporal variation of the force as well as the maximum force acting on the cylinder are well estimated by the semi-analytical models. A new engineering formula is finally developed, accounting for the inclination and surge motion of the cylinder. The impact loads computed with this formula also show good agreement with the experimental tests.
Predicting Weather Down Time for an Offshore Wind Turbine Installation Vessel (WTIV) With Feeders Using Rapid Spectral RAO-Based Hindcast Vessel Motions in Wave Environment
Authors: Mohtat Ali , Hertel Melissa , Hooper Christopher , Jors Charles , Souquet Benjamin , Van Gundy Coulston
Published: September 2023

The relatively new source of alternative energy, offshore wind energy, has brought many new challenges into the logistics and maritime operations in the north America. “Jones Act Maritime Law” prohibits foreign flagged vessels from transporting cargo between locations within the U.S. territorial sea. This restriction means Offshore Wind Turbine Installers can either build new Wind Turbine Installation Vessels (WTIV) in the United States, or transport wind turbine generators (WTG) using coastwise qualified feeder vessels and foreign WTIVs. The constraints on the motion and acceleration of WTG components may limit operations or require motion compensation systems. To support system design, a tool is required that allows the user to evaluate the difference is uptime between different vessels, load conditions, motion compensation equipment and lifting appliances. Traditional weather down time analysis evaluates operations against hind cast environmental data. The method described here expands the weather downtime simulation to include cargo motions and accelerations and vessel responses. The results can then be used to evaluate the relative value of each feeder type or motion compensation system to inform installation system design, risk analysis and contracting.

The model is applied to analyze multiple candidate feeder vessels and various turbine models, transit routes, and installation sites covering 41 years of hourly hindcast data. To accommodate this scope, a technique is applied to rapidly compute vessel motions using pre-computed Spectral Response Amplitude Operations (SRAOs) at each hindcast time step. The SRAO database has parameters of wave heading (ϕ), modal period (Tp), significant wave height (Hs), directional cosn spreading, and spectral shape (γ). SRAOs are referenced for each wave condition to approximate motions in wind waves and swell. This method offers quick turnaround, simulating millions of hours of hindcast vessel motions in a few hours of computational time on a 120-core cluster. Weather uptime for this sensitive operation is drastically increased in some instances when the feeder vessel can be aligned to the predominant wave direction. By capturing the underlying hydrodynamics in the proposed simulation, the method presented here can be applied to understand project schedule risk and fleet logistics during the project planning stages. This model can be further leveraged to offer operational guidance to the vessel operator during the wind farm construction phase.
Spatial-Temporal Evolution Of The Regional Shipping Network: A Case Study of Ports Along the Maritime Silk Road
Authors: Zhou Yong , Luo Shihui
Published: September 2023

Since the 21st Century Maritime Silk Road (MSR) initiative was launched in 2013, sixty-five countries and regions have already joined the construction of the MSR, and the development of blue economy has gradually become an international consensus. In order to investigate the impact of the MSR initiative on port developments and regional economy, this paper focuses on analyzing the spatial-temporal dynamics and evolution of shipping network among and within port clusters along the MSR. Specifically, a shipping network consisting of ports along the MSR and shipping routes is firstly built based on the complex network theory. Then a variety of data related to port infrastructure and operation as well as regional economy are collected and processed. With the aid of Herfindahl-Hirschman index (HHI) and Zipf’s law, the shipping network will be analyzed from the perspectives of network structure and market shares and size distribution of the involved ports. The results can be used to understand the changes in the pattern of seaborne trade along the MSR, and provide decision support for the sustainable development of economic globalization and regional economic integration.
From Offshore Flexible Flowlines to Dynamically Installed Anchors – A Concept Study
Authors: Hu Yuxia , Gao Minghui , Draper Scott , Hossain Muhammad Shazzad
Published: September 2023

Decommissioned subsea flexible flowlines and umbilicals pose a particular waste management challenge as there is limited capacity to process these materials in Australia. Approximately 3200 km of flexible flowlines and umbilicals will be decommissioned in Australia over the next 3 decades. Research can play a significant role in developing and validating approaches to better recycle and repurpose these flowlines and umbilicals, and at a broader scale redefine how industrial waste is managed in Australia.

This paper presents a concept study on designing new dynamically installed anchors using decommissioned flexible flowlines for supporting offshore floating facilities such as floating wind turbines, wave energy converters and floating aquaculture cages. For testing, a new model anchor was designed as if the anchor shaft was truncated from a decommissioned flexible flowline and ‘fish-scales’ were serrated on the external plastic layer of the flowline to enhance anchor holding capacity after installation. The new model ‘fish-scale’ anchor and model conventional deep penetrating anchor were tested for hydrodynamic and geotechnical characteristics. Their performances during free-fall in water and during penetration in clay were compared. The preliminary test results provided confirmation on the concept that decommissioned flexible flowlines could be turned into dynamically installed anchors with potential better performance.
Effect of Nonlinearity on Tubular Joint of Jacket Structure and its Response Under Dynamics Loading
Authors: Kumar Ram , Kumar Deepak
Published: September 2023

The jacket structure is one of the most important offshore structures. It’s a relatively stiff structure because its base is fixed to the foundation. Due to the fixidity at the bottom its natural period of vibration is much small in comparison to other floating structures. A jacket structure is framed structure that is generally made of tubular members and each member is connected rigidly. Under a huge load of platform and ocean waves, the member’s connection/joint undergoes rotation and deformation. Due to rotational and deformational responses at joints, the nonlinearity develops, and depending on structure properties and load it can be significant enough to affect the responses of the overall jacket structure. In this study, the joint of the jacket structure is remodeled using an analytical technique available in the literature, and the effect of the angle between the members is considered one of the factors for the nonlinearity in its flexibility matrix. The present study shows that considering the changing angle between the members shows a higher degree of nonlinearity in the flexibility matrix. Further, the same joint is modeled in Abaqus software for understanding the analytical results obtained previously. Further, buckling of the tubular member at the joint level due to external load is also considered in Abaqus for obtaining the relationship between load and displacement. This helps in obtaining the nonlinear stiffness matrix in the concerned degrees of freedom under the consideration of varying angles between members and buckling at the joint level of the tubular member. Further, the obtained nonlinear stiffness matrix is utilized to do the dynamic analysis of the joint in its concerned degree of freedom. Study shows that the nonlinear effect of joint is considerable enough and its effect is visible on dynamic response.
LSTM-Based Model Predictive Control for Motion Stabilized Platform of Doppler Lidar for Offshore Wind Observation
Authors: Kinugasa Mizuki , Yamamoto Yusuke , Terada Daisuke , Katayama Toru
Published: September 2023

In this study, the applicability of a controlled method based on LSTM (Long Short Term Memory) to motion reduction of a rigid body swing as a motion stabilized platform to place on floating platform is investigated numerically. First, for a single pendulum type motion stabilized platform on a spar-buoy type floating platform with tension-mooring, the sequential control torque required to cancel external torque is calculated. Next, one step ahead motion velocity and acceleration of the spar-buoy are predicted by using LSTM model, which is a kind of machine learning model for time series forecasting. Based on the predicted results, the effectiveness of model predictive control to reduce its motion is tried to be confirmed. However, it is difficult to reduce the motion because of prediction error. Then, skyhook dumper is applied to damp undesired control torque caused by the error. As the result, its pitch becomes less than one degree on the moderate wave condition, and magnification factor of motion amplitude of the single pendulum type motion stabilized platform becomes less than one.
A Systematic Approach for Developing a Numerical Wavetank to Simulate Driven Shallow- and Deep-Water Waves
Authors: Rehman Wajiha , Bokhove Onno , Kelmanson Mark
Published: September 2023

Numerical models of wavetanks for nonlinear waves driven by waveflap/piston wavemakers are developed. Variational principles (VPs) for the underlying equations of nonlinear potential-flow dynamics are implemented directly in the finite-element-based environment Firedrake. The establishment of mathematical and numerical wavetank models, based on VPs and domain-specific compiler architecture, is a novel challenge aimed at both reducing time-to-development and enabling new model experimentation. The waveflap-wavemaker problem is fundamentally more complex than the piston-wavemaker problem since reformulation of the mathematical problem into a computational domain respectively demands multi- and single-step transformations because of the respective two- and one-dimensional wavemaker motions. Hence this paper presents a systematic approach for developing a numerical piston/waveflap wavemaker wavetank, within the widely available Firedrake environment, that can simulate the dynamics of both shallow- and deep-water waves.
Experimental Modeling of Water-Wave Interactions With a Flexible Beam
Authors: Rehman Wajiha , Bunnik Tim , Bokhove Onno , Kelmanson Mark
Published: September 2023

A series of fluid-structure-interaction (FSI) experiments is presented for studying water-wave interactions with a flexible beam in a wide range of sea conditions thus yielding a variety of FSI test-case data. The aim is to use these experimental data in order to validate FSI solvers commonly employed by the maritime industry in the design of fixed-foundation, offshore wind turbines. The experimental setup allows simultaneous measurements of beam deflections and their effect on incident and reflected waves. In addition, the study is carried out in a wide range of sea conditions ranging from regular-to-irregular and moderate-to-extreme wave height and steepness. The study of such a wide range of conditions makes the experiments suitable for providing reliable data in the validation of a suite of mathematical and numerical FSI solvers, i.e., linear, nonlinear and high-fidelity. The data from the experiments will be made publicly available through open-source data-sharing platforms.
Aerodynamic Investigation of Tower Shadow Effects on the Horizontal Axial Dual-Rotor Wind Turbine
Authors: Zhao Mengshang , Zha Ruosi , Wang Kai , Wu Xiaodi , Chen Siqi
Published: September 2023

In this paper, unsteady numerical simulations for horizontal axis dual-rotor wind turbines with and without a tower were carried out using the actuator line model (ALM) instead of the traditional body-fitted mesh and the large eddy scale (LES) turbulence model to improve the numerical accuracy of the wake. The power coefficient Cp, axial force coefficient Cz and velocity distribution in the near wake were used to validate the accuracy of ALM based on model experimental results of a conventional wind turbine. The results indicated that ALM can accurately predict the aerodynamic performance and wake characteristics which agreed well with the experimental data. Tower shadow had little influence on average aerodynamic performance. But, it can significantly increase the fluctuation amplitude of the dual-rotor wind turbine. Both 1-time RF (rotational frequency) and 2-time RF were nearly noticeable for the dual-wind turbines in the case with a tower, while 2-time RF was obviously remarkable for the dual-rotor wind turbine in the case without a tower. The distribution of the transverse velocity was generally symmetrical in the near wake of 1-5D away from the wind turbine, but the distribution of the longitudinal velocity lost symmetry due to the tower shadow. However, the tower shadow had a negligible effect on the velocity recovery in the far wake.
Impact of Cleaning Efficiency on Disc Cutter Drilling Performance
Authors: Akindele Oluwatimilehin Mary , George Judith Onyedikachi , Abugharara Abdelsalam , Butt Stephen D.
Published: September 2023

Large diameter drilling operations, including tunnel boring and raise boring, are capital-intensive projects. As such, proper estimation of time and cost is critical to the planning of the drilling project. To arrive at the correct estimation of the drilling time during the drilling phase, accurate prediction of the drilling performance is needed. In large diameter applications, disc cutters are the primary cutting tools, hence, several investigations have focused on developing accurate estimation of disc cutter forces. Other studies have also sought to understand the impact of rotary speed and cutter geometry on drilling performance. This study seeks to contribute to existing body of knowledge by evaluating the impact of cuttings cleaning efficiency on disc cutter drilling performance. This technical paper presents the results of two sets of drilling experiments. Both experiments were conducted under atmospheric condition on the same granite block using same rotary cutting machine and tri-disc disc cutter with tungsten carbide inserts. Same drilling parameters were applied during each of these experiments. However, the difference lay in the adopted cuttings evacuation method. One drilling procedure adopted the dry method wherein the cuttings were evacuated with vacuum while in the second procedure, the cuttings were cleaned using the jetting action of a high spray nozzle. The results of these experiments show how much influence the cleaning efficiency has on the disc cutter drilling performance.
A New Multi-Criteria Decision-Making Tool for Subsea Oil and Gas Asset Decommissioning
Authors: Caprace Jean-David , Lourenço De Souza Marcelo Igor , Violante Ferreira Claudio , Ribeiro Nicolosi Eduardo
Published: September 2023

The designed life of many offshore O&G facilities is reaching its end. Decommissioning these facilities has become a critical task due to unpredictable costs, high operational risks, potential social impacts, and finally, environmental protection issues. Decision making plays a decisive role in finding a trade-off between the concerns and interests of stakeholders such as O&G companies, government bodies, environmental protection organizations, sea and coastal environment users, and local communities. The decision problem is often complex as it usually involves several criteria. Most of the time, there is no one perfect option available to suit all the criteria: an ‘ideal’ option does not usually exist. Therefore, a compromise must be found. To address this problem, the decision-maker may use advanced approaches such as Multi-Criteria Decision Analysis (MCDA). These models have recently attracted the attention of the industry. Here, we describe a new tool that improves the decision-making process ranking the different decommissioning options of O&G subsea assets. This model considers 37 attributes gathered into 6 criteria: Safety, Environment, Waste management, Technical, Social, and Economic. Several decommissioning alternatives are compared. The new tool has been tested on the Brazilian decommissioning of Espadarte Field, showing remarkable performance in aiding the decision-making process.
CFD-Based Simulation for the Stability of Floating Solar Arrays
Authors: Arora Prince , Prasad Patel Badri , Ahmad Suhail , Jain Arvind Kumar , Joe Joe C. S. , Aggarwal Pratham
Published: September 2023

Floating solar energy technology, among other renewable energy, is growing exponentially, owing to reduced water evaporation from the water body and much less land requirement. Floating Photovoltaic (FPV) panels can be installed in any water body, viz. lakes, balancing reservoirs, backwaters, dam reservoirs etc. However, the FPV system is very complex due to the involvement of multiple types of equipment to name a few: - floats, anchoring & mooring system, solar modules, string monitoring unit, power conditioning units, LV switchgear, cables, inverter transformer, AC & DC cables, lightning arrestors etc. Further, this complexity increases during different project phases (erection, installation, towing of arrays, commissioning etc.), with variable water depth due to bathymetry and frequent water level changes in the case of a dam reservoir. In addition to that, system connection must be flexible with modular installation. Worldwide, FPV is gaining commercial interest due to its low LCOE and researcher interest due to its vast research potential.

One significant challenge in the design, engineering & installation of FPV is the unavailability of international codes & standards. The only recommended practice for FPV is DNVGL-RP-0584, which still requires many improvements. While designing the system, most industries follow the extreme wind conditions applicable for buildings but do not precisely describe the situation specific to floating solar. In the recent past, one of the floating solar parks collapsed due to a strong wind gust[1].

A solar array is first modelled in the present work, and its aerodynamics is investigated through CFD in ANSYS FLUENT. A parametric study is then carried out with the variable inclination angle of solar panels. The wind loads are then compared with a standard analytical approach considering the wind pressure acting on the projected area. An optimized size of the solar array is recommended based on CFD loads at a particular inclination angle of the solar panel. Such a study helps design an FPV park without the code.
The Relationship Between Lower-Body Force–Time Variables and Skating Performance in Female Ice Hockey Players
Authors: Geneau Mary C. , Tsai Ming-Chang , Agar-Newman Dana , Geneau Daniel J. , Klimstra Marc , James Lachlan P.
Published: September 2023

Purpose: Ice hockey is a team invasion sport characterized by repeated high-intensity skating efforts, technical and tactical skill, physical contact, and collisions requiring considerable levels of muscular strength. The purpose of this study was to evaluate the relationships between lower-body vertical force–time metrics and skating qualities in subelite female ice hockey players. Methods: A cross-sectional cohort design was employed utilizing 14 athletes (body mass = 66.7 [1.8] kg; height = 171.6 [6.2] cm; age = 21.1 [1.7] y). The relationships between metrics of lower-body strength collected from a drop jump, squat jump, countermovement jump, loaded countermovement jump, and an isometric squat and 4 skating qualities collected from a linear sprint, repeated sprint test, and a multistage aerobic test were evaluated. Results: The regression models revealed a positive relationship between relative peak force in the isometric squat and skating multistage aerobic test performance (r2 = .388; P = .017) and a positive relationship between repeated-sprint ability and eccentric mean force during the loaded countermovement jump (r2 = .595; P = .001). No significant relationships were observed between strength metrics and skating acceleration or maximal velocity. Conclusions: These data suggest that skating ability is most affected by relative isometric strength in female ice hockey players. It is recommended that practitioners focus training on tasks that improve relative force output. It is also recommended that isometric relative peak force be used as a monitoring metric for this cohort.
Regulatory circuits of mitophagy restrict distinct modes of cell death during memory CD8
+
T cell formation
Authors: Franco Fabien , Bevilacqua Alessio , Wu Ruey-Mei , Kao Kung-Chi , Lin Chun-Pu , Rousseau Lorène , Peng Fu-Ti , Chuang Yu-Ming , Peng Jhan-Jie , Park Jaeoh , Xu Yingxi , Cassotta Antonino , Yu Yi-Ru , Speiser Daniel E. , Sallusto Federica , Ho Ping-Chih
Published: September 2023

Mitophagy, a central process guarding mitochondrial quality, is commonly impaired in human diseases such as Parkinson’s disease, but its impact in adaptive immunity remains unclear. The differentiation and survival of memory CD8
+
T cells rely on oxidative metabolism, a process that requires robust mitochondrial quality control. Here, we found that Parkinson’s disease patients have a reduced frequency of CD8
+
memory T cells compared with healthy donors and failed to form memory T cells upon vaccination against COVID-19, highlighting the importance of mitochondrial quality control for memory CD8
+
T cell formation. We further uncovered that regulators of mitophagy, including Parkin and NIX, were up-regulated in response to interleukin-15 (IL-15) for supporting memory T cell formation. Mechanistically, Parkin suppressed VDAC1-dependent apoptosis in memory T cells. In contrast, NIX expression in T cells counteracted ferroptosis by preventing metabolic dysfunction resulting from impaired mitophagy. Together, our results indicate that the mitophagy machinery orchestrates survival and metabolic dynamics required for memory T cell formation, as well as highlight a deficit in T cell–mediated antiviral responses in Parkinson’s disease patients.
Draft genomes of
Lactobacillus delbrueckii
and
Klebsiella pneumoniae
coexisting within a female urinary bladder
Authors: London Laricca Y. , Lim Chae Hee , Modliszewski Jennifer L. , Siddiqui Nazema Y. , Sysoeva Tatyana A.
Published: September 2023

Here, we present the draft genome sequences of
Lactobacillus delbrueckii
and
Klebsiella pneumoniae
, both isolated from the urinary bladder of an asymptomatic post-menopausal female patient with a diagnosis of recurrent urinary tract infections. These genomes will facilitate analyses of interbacterial interactions in the urinary microbiome.
In vitro
activity of cefiderocol against comparators (ceftazidime-avibactam, ceftazidime-avibactam/ aztreonam combination, and colistin) against clinical isolates of meropenem-resistant
Klebsiella pneumoniae
from India
Authors: Borde Kalyani , Kareem M. A. , Sharma Ratna Mani , Dass S. Manick , Ravi Vedantham , Mathai Dilip
Published: September 2023

Cefiderocol (FDC), a novel siderophore drug, is active against Gram-negative bacteria producing carbapenemases, including metallo-beta-lactamases. The objective of this study is to compare the
in vitro
activity of FDC with ceftazidime-avibactam (CZA), CZA/aztreonam (AT) combination, and colistin (CST), in clinical isolates of meropenem-resistant (MER-R)
Klebsiella pneumoniae
. From the 2,052 clinical specimens submitted for culture testing, 245
K
.
pneumoniae
isolates were recovered within a 6-month period in 2021. One hundred three non-duplicate, non-outbreak, MER-R (minimum inhibitory concentration, MIC >4 µg/mL) strains were included in the study. Identification and susceptibility were performed using VITEK-2 (bioMérieux). Meropenem-susceptible isolates (
n
= 10) served as controls. For FDC, broth microdilution (BMD) was performed after in-house standardization. Disk diffusion (Liofilchem, Italy) and broth microdilution (ComASP, STC, Liofilchem, Italy) were used for susceptibility testing of CZA and CST, respectively. Synergy testing for CZA and AT was performed using disk approximation method. CLSI breakpoints were used for the interpretation of the results. For FDC, MIC
50
and MIC
90
were 2 and 8 µg/mL, respectively. A total of 80% of isolates were susceptible to FDC, 26.2% of isolates were susceptible to CZA, synergy testing with CZA/AT was positive for 74 (72%) of the isolates, and 89.3% were intermediate to CST. Nine (8.7%) were susceptible only to FDC. FDC is active
in vitro
against MER-R
K. pneumoniae
>CZA/AT > CZA > CST
,
as observed in this study, applying CLSI criteria. Clinico-microbiological studies should be performed to assess the clinical efficacy of this novel drug in this region with a high prevalence of carbapenem resistance among Gram-negative organisms.

Importance

Management of infections with multi-drug resistant
Klebsiella pneumoniae
is a major challenge in hospital settings, with few treatment options. In this study, the authors aim to assess the
in vitro
susceptibility of these clinical isolates to cefiderocol, a novel siderophore. Comparators are colistin, ceftazidime-avibactam, and ceftazidime-avibactam/aztreonam synergy, which are currently available options for treatment in this region. Baseline-resistance rates against cefiderocol are higher than those in the previously published studies, with MIC50 and MIC90 at 2 and 8 µg/mL, respectively.
Composition of Phenocrysts in Lamproites of Gaussberg Volcano, East Antarctica
Authors: Migdisova N. A. , Sushchevskaya N. M. , Portnyagin M. V. , Shishkina T. A. , Kuzmin D. V. , Batanova V. G.
Published: September 2023

Abstract—This paper presents numerous new data on the geochemical composition of olivine, clinopyroxene, and leucite phenocrysts, as well as spinel inclusions in olivine and quench glass from lamproites of Gaussberg volcano (East Antarctica). Most of the olivine phenocrysts in the Gaussberg lamproites are high Mg varieties (Fo89–91) with elevated Ni contents (up to 4900 ppm) and high Ni/Co ratios. According to data of about 320 clinopyroxene analyses, two groups of diopsidic phenocrysts have been established. Group I consists mainly of high-Mg varieties (Mg#>80), while group II clinopyroxenes are less magnesian (Mg# 52–80). The main difference between the clinopyroxenes of the two groups is the elevated contents of Al2O3, FeO and reduced TiO2, Cr2O3, and NiO in the compositions of group II compared to group I, as well as different contents of trace elements, which may reflect their crystallization from different types of primary melts. According to the study of ~550 grains of leucite phenocrysts in the Gaussberg lamproites, it was shown that they correspond to the ideal stoichiometry of leucite K[AlSi2O6] and are enriched in Na2O (0.05–0.35 wt %), but depleted in K2O (19.9–20.9 wt %) compared to leucites from lamproites of other provinces. The BaO content reaches 0.3 wt %, SrO –0.04 wt %. The iron content in most leucite phenocrysts varies within 0.7–1.2 wt % Fe2O3, but some grains have the low Fe2O3 contents (<0.5 wt %). In leucite microlites of the groundmass and rims of phenocrysts, the Fe2O3 content can reach 2.4 wt %, which may indicate more oxidized conditions at lava eruption. Based on the study of natural samples, existing experimental data and numerical models, the order and conditions of crystallization of the Gaussberg lamproites were obtained. Crystallization proceeded in the following order: chromian spinel → chromian spinel + olivine → olivine + leucite (± chromian spinel) → olivine + leucite + clinopyroxene (± chromian spinel). The near-liquidus assemblage represented by high-Mg olivine phenocrysts with inclusions of Cr-spinel was formed in the temperature range from 1180 to 1250°C. Further crystallization of the melt with the formation of an association of olivine+leucite+clinopyroxene phenocrysts could occur at pressures below 2 GPa and temperatures of 1070–1180°C, corresponding to the presence of water in the magmatic system. Estimates of the redox conditions of crystallization of lamproites obtained using different oxybarometers vary in a wide range from QFM-0.5 to QFM+2.3. The elevated Ni contents in liquidus olivines of Gaussberg indicate the high nickel contents in the source. It is shown that the formation of ultra-alkaline magmas in the Gaussberg volcano area is likely related to melting of the continental lithosphere, which was heterogeneous and included both the peridotite mantle and hydrous pyroxenite fragments.
Interplay between chronic widespread pain and lifestyle factors on the risk of type 2 diabetes: longitudinal data from the Norwegian HUNT Study
Authors: Marcuzzi Anna , Caceres-Matos Rocio , Åsvold Bjørn Olav , Gil-Garcia Eugenia , Nilsen Tom I L , Mork Paul Jarle
Published: September 2023

Introduction

Chronic widespread pain (CWP) and diabetes commonly co-occur; however, it is unclear whether CWP infers an additional risk for diabetes among those with known risk factors for type 2 diabetes. We aimed to examine if CWP magnifies the effect of adverse lifestyle factors on the risk of diabetes.

Research design and methods

The study comprised data on 25 528 adults in the Norwegian HUNT Study without diabetes at baseline (2006–2008). We calculated adjusted risk ratios (RRs) with 95% CIs for diabetes at follow-up (2017–2019), associated with CWP and body mass index (BMI), physical activity, and insomnia symptoms. The relative excess risk due to interaction (RERI) was calculated to investigate the synergistic effect between CWP and adverse lifestyle factors.

Results

Compared with the reference group without chronic pain and no adverse lifestyle factors, those with BMI ≥30 kg/m2with and without CWP had RRs for diabetes of 10.85 (95% CI 7.83 to 15.05) and 8.87 (95% CI 6.49 to 12.12), respectively; those with physical activity <2 hours/week with and without CWP had RRs for diabetes of 2.26 (95% CI 1.78 to 2.88) and 1.54 (95% CI 1.24 to 1.93), respectively; and those with insomnia symptoms with and without CWP had RRs for diabetes of 1.31 (95% CI 1.07 to 1.60) and 1.27 (95% CI 1.04 to 1.56), respectively. There was little evidence of synergistic effect between CWP and BMI ≥30 kg/m2(RERI=1.66, 95% CI −0.44 to 3.76), low physical activity (RERI=0.37, 95% CI −0.29 to 1.03) or insomnia symptoms (RERI=−0.09, 95% CI −0.51 to 0.34) on the risk of diabetes.

Conclusions

These findings show no clear interaction between CWP and adverse lifestyle factors on the risk of diabetes.
Association of sleep disorders with asthma: a meta-analysis
Authors: Liu Xueqian , Hong Cheng , Liu Zhiyu , Fan Lihua , Yin Moqing , Chen Yunhu , Ren Xiang , Gu Xuefang
Published: September 2023

Background

Animal experiments and clinical trials have revealed a potential relationship between sleep disorders and asthma. However, the associations between these factors remain unclear.

Material and methods

We searched PubMed, Embase, Web of Science and Cochrane Library databases for eligible studies published before 30 December 2022. Studies investigating the association between sleep disorders (insomnia, poor sleep quality and insufficient sleep time) and asthma were selected. Sleep disorders were assessed using questionnaires, interviews, or medical records. Asthma was diagnosed based on medical history and drug use. The Newcastle-Ottawa Scale and the Agency for Healthcare Research and Quality checklist were employed for quality assessment. We used OR with 95% CI as the effect measures and forest plots to display the results. Heterogeneity was evaluated usingI2statistics and subgroup analyses were performed for bias analysis. Publication bias was evaluated using the funnel plots and Egger’s test.

Results

Twenty-three studies were included in the primary analysis, which suggested a positive association between sleep disorders and asthma (OR: 1.38, 95% CI 1.10 to 1.74). Subgroup analyses were conducted according to the study design, age, family history of asthma and type of sleep disorders. We did not find any association between sleep disorders and asthma in children aged ˂12 years (OR: 1.13, 95% CI 0.97 to 1.32). The association was insignificant in studies where the family history of asthma was adjusted for (OR: 1.16, 95% CI 0.94 to 1.42). Funnel plot and Egger’s test indicated a significant publication bias.

Conclusion

Sleep disorders are associated with an increased prevalence and incidence of asthma. However, the quality of the evidence was low because of potential biases.

PROSPERO registration number

CRD42023391989.