bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrodynamic Investigation of a Remora-Inspired Autonomous Underwater Vehicle Docking Onto a Benchmark Submarine
Authors: Xu Yunxin , Shi Weichao , Stark Callum
Published: October 2022

To improve the cost-effectiveness and safety of offshore operations, autonomous underwater vehicles (AUVs) are widely used in various fields. However, traditional docking or recovery methods for AUV’s can be very inefficient as they require the mother vehicle to be stationary. Therefore, to reduce recovery operation cost, shorten the redeployment time and increase operational efficiency when compared to traditional docking methods, the development of underwater dynamic recovery systems for AUVs is critical. Recently the ‘hitchhiking’ behavior of remoras which have a symbiotic relationship with sharks has been investigated, and the numerical results showed that the boundary layers and adverse pressure gradient regions around the shark can provide a significant drag reduction on the remora when it attaches to the shark. To support the feasibility study of the underwater dynamic recovery system of AUVs, this paper develops a remora-like AUV and investigates the potential docking locations on a benchmark submarine, using the commercial computational fluid dynamics (CFD) software, STAR-CCM+. Self-propulsion simulations are conducted to identify the resistance performance of the AUV in different locations as affected by flow around the submarine. The boundary layer and the adverse pressure gradient are the two key elements that affected the AUV resistance. By researching the hydrodynamic characteristics, an optimal docking area is identified and presented to be further researched to fully enable this advanced dynamic docking operation.
Finite Element Modelling of Ocean Thermal Energy Conversion (OTEC) Cold Water Pipe (CWP)
Authors: Adiputra Ristiyanto , Utsunomiya Tomoaki
Published: October 2022

An OTEC CWP can be modelled as a submerged free-hanging pipe conveying fluid. The large amount of the required transported deep seawater might cause catastrophic failure of the pipe due to Centrifugal and Coriolis forces driven by the Internal Flow Effect (IEF). To predict the critical velocity, this paper analyzes the stability of the pipe using a Finite Element Method. At the first step, the general motion equation of the pipe is derived and for each term of the equation, its potential energy equation is represented. Using Hermite shape functions, the local matrixes of each element can be obtained based on virtual displacement principle. Flow field and flow direction change at the inlet is considered at the bottom-end of the pipe as a local boundary condition. After the global matrixes of the system are produced, the global boundary conditions are imposed. Finally, the system is solved using the Newmark time-scheme method. The result are then compared to the previous published works of a small scale model. After being verified, the developed FEM will be used to analyze the full-scale model of the OTEC CWP. The result shows that the critical velocity is around 4.5–4.8 m/s.
Sea Trials Summarization on Fundamental Formation Control of Multiple Cruising AUVs -2nd Report: 3 Cruising AUVs With 1 ASV Trial, and Hovering AUVs’ AUV-AUV Positioning and Communication-
Authors: Fujiwara Toshifumi , Kim Kangsoo , Sasano Masahiko , Sato Takumi , Inaba Shogo , Okamoto Akihiro , Imasato Motonobu , Osawa Hiroyuki
Published: October 2022

National Maritime Research Institute (NMRI) has been studying the development of multi-vehicle operation technology for autonomous underwater vehicles (AUVs) and an autonomous surface vehicle (ASV) mainly from the viewpoint of efficient operation. These results were obtained through our participation in the 2nd term Cross-ministerial Strategic Innovation Promotion Program (SIP2), “Innovative Technology for Exploration of Deep Sea Resources” in Japan. In the project, NMRI is promoting an advanced control system for AUVs initiatively together with the lead agency, Japan Agency for Marine-Earth Science and Technology (JAMSTEC).

This paper is placed as the second report in the series. The contents of the paper show the results of the fundamental formation control with three cruising AUVs and one ASV in the sea, and the results of AUV-AUV positioning and communication tests with two hovering AUVs. As a result, in the case of the trial of the fundamental formation control, seafloor topography mapping at the coast in Japan was successfully conducted by the AUVs control system. Moreover, two hovering AUVs navigated with positioning and communication each other in the sea having no problem.

The results of the two trials are reported and summarized.
The Effect of Pitting Corrosion on Fatigue Performance of Mooring Line Chain Links
Authors: Rezende Filipe A. , Simão Marina L. , Videiro Paulo M. , Sagrilo Luis V. S.
Published: October 2022

Mooring systems play an important role in the safety of floating production units and must comply with ultimate, accidental, and fatigue limit states criteria defined by design standards and classification societies. However, in the last few decades, many mooring lines failures have been reported in the literature. Most of these were related to fatigue and corrosion degradation in the top chain links, becoming a major concern. Since then, a great effort has been made to improve fatigue assessment methodologies of these elements and to model the effects that are not properly considered in the current design practice, such as the mean tension effect and the chain-link surface roughness due to localized corrosion.

The design practice of mooring lines usually assumes a uniform corrosion model with a constant corrosion rate. That way, corrosion degradation is considered only by reducing the net area of the chain-link. As a consequence, effects of stress concentration due to localized pitting are not directly addressed, and this may lead to an unconservative design.

The present work aims at assessing the stress concentration associated to chain links with pitting corrosion employing finite element analyses and by comparing the localized pitting against the uniform corrosion stresses conditions in the chain link hotspots. Results highlight that, even for small pits, fatigue damages are higher than considering a uniform area reduction, showing one feasible way of improving the current fatigue design methodologies.
Freak Wave Forecasting: A Data-Driven Approach
Authors: Breunung Thomas , Balachandran Balakumar
Published: October 2022

Freak waves, waves significantly higher than neighboring waves, are a serious threat to ships and marine infrastructure. Despite significant refinement of operational wave models and recent progress in studying the theoretical foundations of such extreme events, the emergence of these events remains unpredictable. In this work, the authors propose a data-driven wave forecasting approach by combining the essence of common wave models, rapid oscillations, and slowly changing spectrum with data-driven techniques such as recurrent neural networks. A judicious minimization procedure is developed, wherein the sea surface elevation is first decomposed into harmonic functions with varying amplitudes. Then, the amplitude variations are forecasted by fitting universal, black-box models. This approach, which can be used to forecast wave crests and troughs in real time, is tested on available buoy data. Overall, the developed models and fitting strategies outperform simple benchmarks indicating the approach’s potential for operational, real-time wave forecasting.
Experimental Study on Temporary Plugging Diverting Acidification of Heterogeneous Sandstone Reservoirs
Authors: Nan Zhao , Liwei Zhang , Rongjun Wang , Qing Wang , Mengchuan Zhang , Erdong Yao , Bo Wang
Published: October 2022

Matrix acidizing is the primary well stimulation method applied to increase the oil and gas production of sandstone reservoirs. However, for reservoirs with many small layers and strong heterogeneity, the permeability of the thief zone is increased because a large amount of acid is easy to enter it, and the less permeable layer that needs to be stimulated cannot be improved, which lead to the interlayer heterogeneity more serious. The method of uniform distribution acid in heterogeneous sandstone reservoirs has been rarely studied. In this paper, temporary plugging and diverting acidizing is suggested to solve the problem of uniform acid distribution in heterogeneous sandstone reservoirs. The temporarily plugged powder is trapped in the front edge of the high-permeability core to form a filter cake. The acid is forced to enter the low-permeability core to achieve uniform acidification.

The results show that the dissolving rate of 50 and 100 mesh temporarily blocked powders is more than 99% under the condition of reservoir temperature and can flowback entirely to the surface without harming the reservoir. The core flooding experiment shows that a 2MPa diverting pressure was induced by 0.1% temporary plugging powder. when the permeability level difference is 50, the permeability of the low permeability core can be improved by more than 50%. It indicated that the temporary plugging powder has a strong plugging ability for high permeability core and a good stimulation effect for low permeability core. Laboratory experiments show that temporary plugging diverting acidification (TPDA) has an excellent stimulation effect on the reservoir with strong heterogeneity in the long well section, which will be an important reference for the realization of uniform acidizing.
Evaluation and Interpretation on Data Driven ROP Models From Engineering Perspectives
Authors: Fernández Berrocal Miguel , Cao Jie , Sui Dan
Published: October 2022

Recently machine learning (ML) technology has been adopted in the Oil and Gas industry as solutions to the most demanding problems like drilling parameters estimation and prediction, drilling incidents detection, optimal well planning etc. Rate of penetration (ROP) modeling is complicated since the ROP is affected by many interacted parameters/factors, and there is no obvious correlation between a single drilling parameter and the target ROP value. Different variables, e.g., weight on bit (WOB), rotary speed (RPM), standpipe pressure (SPP), formation/bit properties, interact such that it is difficult to formulate an accurate mathematical model to describe their correlations. Thanks to a big amount of available field data, the ML becomes a powerful tool to develop data-driven ROP models.

It is a positive sign that many good results from data-driven ROP models have been presented in recent years. However, the limitations of ML approaches like data generality, quality and selection, model evaluation and interpretation, model generality, robustness and stability, and model validation might be the barriers to implementing data-driven techniques to drilling operations in real life. Therefore, our study aims to evaluate and analyze data-driven ROP models with different engineering perspectives, including:

1) Data: how does data affect the data-driven ROP model behavior?

2) Performance metric: which one is suitable to evaluate the error of the estimation/prediction, e.g., coefficient of determination (R2), mean absolute error (MAE), mean absolute percentage error (MAPE) or others?

3) Dynamics: How to evaluate the ROP model dynamics?

4) ML models: how well do the data-driven ROP models perform in the ROP optimization?

From the case studies in this research, the comprehensive results are shown to evaluate the developed ROP models with respect to the above-mentioned aspects. The work focusing on model evaluation and engineering interpretation facilitates a better understanding of the data-driven models and their applications. It also presents a new evaluation method using trend analysis.
Classification of Ice-Induced Vibration Regimes of Offshore Wind Turbines
Authors: Hammer Tim C. , Owen Cody C. , van den Berg Marnix , Hendrikse Hayo
Published: October 2022

Ice-induced vibrations of offshore wind turbines on monopile foundations were investigated experimentally at the Aalto Ice Tank. A real-time hybrid test setup was developed allowing to accurately simulate the motion of a wind turbine in interaction with ice, incorporating the multi-modal aspects of the interaction and the effect of simultaneous ice and wind loading. Different vibration patterns were observed where some could be described based on the common terminology of intermittent crushing or continuous brittle crushing. However, not all resulting vibrations could be described accordingly. A combination of several global bending modes interacting with the ice resulted in high global ice loads and structural response. Such response is likely typical for an offshore wind turbine, owing to the dynamic characteristics of the structure. The type of interaction observed during the tests would be most critical for design as the largest bending moments in critical cross-sections of the foundations occur for this regime. A classification of ice-induced vibrations is proposed which encompasses the experimental observations for offshore wind turbines on the basis of the periodicity in the structural response at the ice action point.
The Effect of Fluid Contamination on Rheological Properties of Geopolymer Materials
Authors: Khalili Pouya , Khalifeh Mahmoud , Saasen Arild
Published: October 2022

Providing zonal isolation and ensuring long-term integrity are among the highest priorities in primary cementing during well construction. There are several factors that compromise a successful cementing job. One of them is contamination with drilling fluid. Since there is drilling fluid in the wellbore prior to pumping the cementitious material, it is highly likely that intermixing between these fluids occurs in the downhole, which in turn can lead to several effects on mechanical properties and rheological behavior of the Portland cement or alternative materials such as geopolymer. In the placement process of the cement slurry, spacer fluids and prewashes are pumped ahead of the cementitious slurry to minimize the intrusion of drilling fluid into the slurry and consequently improving bonding to the casing and formation. In designing spacer fluids that can efficiently displace the drilling fluid, it is necessary stress test the cementitious material. The rheological properties and density of both cementitious slurries and drilling fluids and must be evaluated. Failing to properly characterize the fluids in the wellbore may lead to developing a spacer or displacing fluid that can cause viscous fingering and leave a static mud layer in the annulus.

In the present work, rotational test with controlled shear rate and oscillatory test were conducted on drilling fluid (water-based and oil-based) and geopolymer to identify rheological behaviors. Based on the mentioned tests, storage and loss modulus, yield stress, and flow curve of the slurries were also measured. For completeness of measurements and comparison purposes, the flow curve was measured with both an API viscometer and a proper rheometer. Obtained parameters can give us a good understanding of the flow behavior of the fluids when pumped downhole under certain shear conditions and, as a result, establish a good basis for spacer design for geopolymer as a new under-development cementitious material.
Development of a Response Assessment Tool for a Floating Dock System
Authors: Zhang Jianan , Li Lin , Ong Muk Chen , El Beshbichi Omar , Kniat Aleksander
Published: October 2022

Docking operations of ships require a response assessment to ensure structural and personnel safety. Environmental loads and improper ballast adjustments are the main threats to the docking operations. They can cause severe structural damages and stability loss to a floating dock system which includes a floating dock and a docked vessel, even if the velocities of the dock and the vessel are very low during the docking process. Response assessment of the floating dock system, including structural strength analysis and stability check, needs to be performed for a safe docking operation. This paper aims to propose a framework of a floating dock system’s response assessment. The stages of ship docking operations are firstly described. The environmental and operational risks involved in those stages are discussed in detail. Then, relevant studies on the structural strength assessment and stability analysis of floating docks are reviewed. Based on the review, a framework to perform a response assessment of a floating dock system is proposed and discussed with a focus on the dynamic response analysis. A numerical model of the dynamic response assessment is established using the language Modelica. A preliminary case study of a single dock under pure wave conditions is presented.
A Coupled Wave-Current-Structure Study for a Floating Offshore Wind Turbine Platform
Authors: Li Xiang , Xiao Qing , Gonçalves Rodolfo T. , Peyrard Christophe
Published: October 2022

In the present study, the influence of ocean conditions, in the combination of wave and current, on the dynamic response of the OC4 semi-submersible platform is numerically studied. The present work is inspired by the recent observations that the presence of current incidence usually induces the vortex-induced motions (VIM) phenomenon of multi-monocolumn platforms, while wave often leads to large inertia force on it. The integration of wave and current may further cause a more complex flow field around the structure than that only wave or current exists. Such VIM is not desirable considering its impact on the fatigue life of the riser, umbilical, and mooring system of the offshore structure due to the resonance behaviour of the VIM.

A computational fluid dynamic (CFD) method is adopted to conduct a real-time simulation of the platform’s motion response. The tool is based on an open-source code library OpenFOAM. The results are validated against experiments with current-only conducted in the wave tank. The flow field around the platform and its impact on the structure motion and loading response are studied for a wide range of wave and current conditions. With the given incident waves, the VIM is mitigated for most cases, for a wide range of reduced velocity. This result is of practical interest for the design of FOWT, as VIM are not captured by industrial aero-hydro-mechanical models.
A Novel Approach in Modelling Fluid Flow in Unconventional Reservoirs Incorporating Viscous, Inertial, Diffusion, Desorption and Advection Forces Contributions
Authors: Aldhuhoori Mohammed , Belhaj Hadi , Ghosh Bisweswar , Alkuwaiti Hamda
Published: October 2022

A model for single-phase fluid flow in tight UCRs was previously produced by modifying the flow Forchheimer’s equation. The new modification addresses the fluid transport phenomena into three scales incorporating a diffusion term, a desorption term and an advection term. In this study, a new model has been numerically validated and verified using synthetic data. Ideally, the new model suits fluid flow in tight UCRs. The modified Forchheimer’s model presented, produced very simple profiles and flow dynamics of the main flow parameters have been established and a thorough parametric analysis and verifications were performed. It has been observed that a system containing the aforementioned forces becomes more prominent in regulating flow velocity with low permeability of the formation rock and low viscosity of the flowing fluid. The findings indicate a behavioral alignment with a previous hypothesis that matches actual reservoir behavior.
Jet Cleaning Processes in the Plug and Abandonment of Oil and Gas Wells: An Experimental Study on Horizontal Miscible Jets
Authors: Hassanzadeh Hossein , Cournoyer Elliott , Taghavi Seyed Mohammad
Published: October 2022

The plug and abandonment (P&A) operation is considered as one of the essential stages during life cycle of oil and gas wells. During the P&A operation, each well needs to go through the specific steps; these may include accessing behind the casing (i.e. annulus), cleaning the target area (i.e. inside and outside the casing), and installing the cement plug barriers in the target area. The jetting process is one of the efficient approaches in the cleaning step of P&A operation, where an injection fluid pushes and removes unwanted fluids/materials. To achieve an efficient jet cleaning process, studies on the effects of different parameters (e.g. operational parameters, fluid properties, and geometrical parameters) seem crucial.

In this paper, we experimentally study the characteristics of horizontal miscible jets, to develop an understanding about fundamental aspects of the jet cleaning process in P&A operation. We analyze the effects of the injection velocity, the perforation diameter, and the rheological parameters on jet characteristics, such as the laminar length and the mixing index. Based on our results, increasing the injection velocity leads to a decrease in the laminar length. Also, the mixing index before the perforated wall increases by decreasing the perforation diameter. In addition, using a non-Newtonian ambient fluid results in decreasing the mixing index.
Finding Dangerous Waves – Towards an Efficient Method to Obtain Wave Impact Design Loads for Marine Structures
Authors: van Essen Sanne , Seyffert Harleigh
Published: October 2022

Green water and slamming wave impacts can lead to severe damage or operability issues for marine structures. It is therefore essential to consider their probability and loads in design. This is difficult, as impacts are both hydrodynamically complex and relatively rare. The complexity requires high-fidelity modelling (experiments or CFD), whereas a statistically sound analysis of rare events requires long durations. High-fidelity tools are too demanding to run a Monte-Carlo simulation; low-fidelity tools do not include sufficient physical details. The use of extreme value theory and / or multi-fidelity modelling is therefore required. The present paper reviews the state-of-the-art methods to find wave impact design loads, which include response-conditioning methods, screening methods and adaptive sampling methods. Their benefits and shortcomings are discussed, as well as challenges for the wave impact problem. One challenge is the role of wave non-linearity. Another is the validation of the different methods; it is hard to obtain long-duration high-fidelity wave impact data. A planned case study is introduced, where different techniques will be put to the test and these challenges will be addressed.
A Validated Computation Fluid Dynamics Model Investigating Cuttings Transport With Herschel Bulkley Drilling Fluids
Authors: Khaled Mohamed Shafik , Khan Muhammad Saad , Rahman Mohammad Azizur , Hasan A. Rashid
Published: October 2022

A fundamental understanding of the impact of different hydrodynamic, scaling, and geometric conditions on cuttings transport are essential for successful wellbore drilling. This study presents a validated computational fluid dynamics (CFD) model for investigating cuttings transport phenomena in deviated wells with Herschel Bulkley drilling fluids at different drilling conditions.

A CFD model was developed and validated with our experiments conducted in the TAMUQ flow loop (5-meter horizontal length, 4.5in. × 2in.) and open literature. The Eulerian-Eulerian approach simulated solid-liquid laminar and turbulent flow in annular geometry utilizing hexahedral mesh under transient conditions.

It was observed that the optimum range for efficient hole cleaning is from 0–200 RPM, and increasing RPM above 200 will have a marginal impact on improving hole cleaning. Cuttings size of 0.004 m was determined to be the critical size for solid particle removal. Hole enlargement has a hugely adverse effect on the fluid-carrying capacity due to the reduction of fluid velocity in the enlarged section and cuttings concentrate. Poor hole cleaning signs were observed with increasing cuttings density and wellbore inclination between 45–60 degrees.
Mooring Line Failure Detection in the Absence of Load Monitoring
Authors: Naciri M. , Viola M. , Wang Z. , Yam R.
Published: October 2022

Mooring Integrity Management (MIM) is a key operational aspect for FPSO operators, mooring system designers and Recognized Classification Societies (RCS). MIM programs should include the capability to detect a mooring line failure. When direct or indirect measurement of line tension is available continuously and reliably over time, this requirement can be readily fulfilled. Current industry-wide experience shows it has been challenging to develop robust cost-effective real-time anchor line load monitoring systems for the offshore environment. To remedy this situation, Artificial Intelligence (AI) techniques are used to extract an intact or damage diagnosis for a spread moored unit offshore Brazil based on data readily available in situ. The Intelligent Agent (IA) developed has been reviewed by the Classification Society against Ref. [1] and [2]. Following this review a statement of maturity has been issued Ref. [3] qualifying the new technology.
Pore-Scale Investigation on Dynamic Permeability Characterization of Hydrate-Bearing Sediments
Authors: Chen Mingqiang , Li Qingping , Lyu Xin , Fan Qi , Ge Yang , Lyu Chaohui
Published: October 2022

Natural gas hydrates widely distributed in marine sediments and permafrost have attracted global attention as great potential energy resources. As an important parameter that critically affects the efficiency of gas hydrate production, reported permeability values are observed to be widely scattered due to multiple factors such as hydrate saturation, hydrate pore habit and so on, bringing a great challenge for accurate prediction. In this study, an unstructured hydrate-bearing network model with anisotropy is firstly constructed. Afterwards, a pore-scale flow network model considering hydrate pore shrinking habits is developed. Dynamic permeability evolution is then investigated under different hydrate saturations, pore connectivity, and pore throat size distribution conditions. Results show that the existence of hydrate changes the structure of the hydrate-bearing pore network, which reduces the pore and throat radius distribution as well as the distribution law. Since hydrate preferentially nucleates in large elements of the pore network, the deviation degree of the pore body radius is more significant than that of the throat radius. Dynamic permeability evolution with increased hydrate saturation shows a nonlinear decline trend due to the nonlinearity between pore structures and hydrate saturation variations. Owing to the two competing factors of pore structure variation and coordination number effects on pore-scale flow, dimensionless dynamic permeability under different pore connectivity shows a minor discrepancy. Pore throat size distribution possesses a significant impact on dynamic permeability evolution. Under the premise of fixed size distribution, number, and connectivity of the pore bodies, the smaller the initial throat radius, the more influence hydrate formation and dissociation on the network structure variation, resulting in smaller dimensionless permeability.
Real-Time Ship Motion Prediction Using Artificial Neural Network
Authors: Taskar Bhushan , Chua Kie Hian , Akamatsu Tatsuya , Kakuta Ryo , Yeow Song Wen , Niki Ryosuke , Nishizawa Keita , Magee Allan
Published: October 2022

Models based on Artificial Neural Networks (ANN) have been developed for predicting ship motions using the information about the wave field around the ship and historical time-series of motions. The ANN models developed in this study were able to predict all six degrees of freedom ship motions in irregular wave conditions with different significant waveheight, peak period and wave directions along with directional spreading. Preparation of training, validation and test datasets has been described along with the development and training of ANNs. The models were tested using the observed wave conditions recorded by a wave radar installed onboard the ship.

A physics-based approach has been applied when selecting the length of input and output data. The effect of input and output window length on the accuracy of results was further studied by developing two sets of ANNs with different length of input and output window. Performance of both sets of ANNs on training, validation and test datasets has been presented along with detailed investigation on test dataset. Reducing the length of input window and increasing the length of output window was seen to reduce the accuracy of prediction.
Hydrodynamic Motion Behavior of Air-Cushion-Supported Hexagonal Floating Platform for Offshore Wind Turbine
Authors: He Yining , Hirabayashi Shinichiro , Tabeta Shigeru , Nakajima Toshio , Yamashita Yoshihiko , Yamashita Yuuki , Imai Motoko
Published: October 2022

This paper presents an experimental study of a new floating platform, being supported by air-cushion modules. The platform consists of six hexahedron air cushion units in which their bottom is open to the water surface. A moonpool is placed in the middle of the platform. A 1:47 scale model was used for the measurement of heave, pitch and surge motions in regular wave conditions. To evaluate the effect of a hexahedron air cushion unit, that of barge-type model was tested. The results show that the motion behaviors of the hexagonal air-cushion-type platform are better than those of the barge-type platform in short wave conditions, while behaviors in long wavelength are almost the same.

To evaluate the stability of the hexagonal air-cushion-type platform in windy conditions, a wind turbine of a circular disc-shape was installed on the platform. The thrust acting on the wind turbine and the wind velocity were measured simultaneously. Further, the inclination test of a three-blade wind turbine model was carried out. The results show that the tested hexagonal air-cushion-type platform is sufficiently stable for the practical use of wind turbines of a 20MW capacity. Similarly, platforms of larger size could be used for wind turbines larger than 20MW.
Quadrature Schemes for the Integration of the Free-Surface Green’s Function Within the Open-Source Boundary Element Method Library BEMUse
Authors: Saverin Joseph R. , Grüter Laura
Published: October 2022

The direct boundary element method has a computational expense which scales quadratically with the number of panel elements. This is a significant bottleneck in the application of the method to large systems. As a preliminary step towards the implementation of a solver with linear computational expense, a detailed study is carried out to investigate quadrature schemes for the integration of the free-surface Green’s function over hydrodynamic panels in the frequency domain. Important parameters are investigated including quadrature order, quadrature rule and panel refinement. Integration errors are quantified by comparison to analytical expressions and higher-order quadrature schemes. Important observations relevant to the removal of irregular frequencies are observed for practical implementation into a boundary element method solver. The order of the method is demonstrated and the influence of the quadrature order on this scaling is quantified. The schemes have been implemented within the open-source boundary element code BEMUse. The ability of the quadrature schemes to correctly calculate the surface hydrodynamic potential is validated by comparing to analytical results for a submerged, oscillating hemisphere. The schemes are verified for realistic offshore wind energy floating platforms geometries by comparison to validated software. It is seen that the quadrature methods allow for accurate calculation of added mass, damping coefficients and excitation forces.
Analytical Model for Non-Bonded Flexible Pipe Under High Temperature and Axisymmetric Load and its Application in Upheaval Buckling
Authors: Chen Kunpeng , Zhang Mengmeng , Zhao Bing , Luo Chunmiao , Fu Shixiao
Published: October 2022

In order to prevent pipe blockage and reduce transportation costs, submarine pipes usually use the method of heating and pressurizing the pipe when transporting liquids. The high temperature and high pressure will cause the axial deformation of the submarine pipe, but due to the existence of the boundary between the two ends of the pipe, the axial deformation cannot be released and a certain axial force is generated. When axial force accumulates to a certain extent, buckling failure may occur, that is, thermal buckling of submarine pipes. In the process of buckling prediction, the axial force is an important input parameter. In the current engineering application, the non-bonded flexible pipe is often regarded as a steel pipe for fast calculation of the axial force value. However, since the geometry of the non-bonded pipe is very complex, the radial mutual extrusion and interlayer interaction will affect the axial deformation of the pipe. Therefore, it is not appropriate to simply use the deformation of the steel pipe to obtain the equivalent of the deformation of the non-bonded pipe to obtain the value of the axial force. In this paper, an analytical model for calculating the structural response of non-bonded pipes under high temperature loads and axisymmetric loads is proposed, and the structural responses of non-bonded pipes under high temperature loads and internal and external pressures are analyzed. The axial force is compared with the results obtained by the calculation methods commonly used in the current engineering. Further, the impact of these differences on the soft soil seabed upheaval buckling forecast is analyzed.
Mitigation of Barite Sagging for Proper Well Control: Lab Investigation and Field Application
Authors: Wagle Vikrant , AlYami Abdullah
Published: October 2022

For high-density fluids, achieving the right fluid formula with the right fluid rheology is difficult since excessive heat, dehydration, and solid loading can deteriorate mud properties. Addition of weighting materials such as barite is needed to achieve the desired density to overbalance the well and avoid any possible flow from the formation. However, maintaining a high volume of solid content for barite particles in suspension might be challenging, especially for extended period. The separation of barite from the mud can lead to undesirable density fluctuation as drilling fluid is being circulated throughout the hole. This phenomenon may lead to potential well control incidents and stuck pipes.

The objective of this study is to design new high-density water-based drilling fluids with lower solid content and mitigate the issues arising due to drilling with high-density drilling fluids. The experimental work in this paper involved rheological properties, thermal stability, HT/HP filtration, and static sagging (vertical and deviated) of 120 pcf and 150 pcf high density water-based drilling fluids. The paper will highlight field cases of proper maintenance program on fluid properties to mitigate any potential well control incidents and will recommend fluids formulation properties when using high solid content water-based fluids.
'HĀPAI TE HAUORA’ - ‘IT’S LIKE BREATHING YOUR ANCESTORS INTO LIFE.'
Authors: Carlson Teah Anna Lee , Mullholland Jessie Rae , Jensen-Lesatele Victoria , Calder-Dawe Octavia , Squire Danielle Aroha
Published: October 2022

Rangatahi described ‘hāpai te hauora’ as ‘breathing your ancestors into life’. This paper explores the ways rangatahi Māori make sense of and live ‘hāpai te hauora’ through sharing their stories of navigating wellbeing.Twenty rangatahi Māori (16–20 years) from diverse backgrounds living in Tāmaki Makaurau, Aotearoa (Auckland, New Zealand) were interviewed by Māori researchers. From the resulting rich and insightful data, short pūrākau (narratives) were analysed at a wānanga involving 34 rangatahi to further explore key findings and expressions of wellbeing through art, design and co-creation.Findings indicate that rangatahi Māori know and experience hauora as living shared values. They search for safe spaces, both human and environmental, to grow, challenge and express who they are and who they want to be. Distinctions were consistently made between their own lived culture and the dominant colonial culture. Rangatahi Māori described a yearning to be seen, heard and sovereign just as they are.
In vivo direct imaging of neuronal activity at high temporospatial resolution
Authors: Toi Phan Tan , Jang Hyun Jae , Min Kyeongseon , Kim Sung-Phil , Lee Seung-Kyun , Lee Jongho , Kwag Jeehyun , Park Jang-Yeon
Published: October 2022

There has been a long-standing demand for noninvasive neuroimaging methods that can detect neuronal activity at both high temporal and high spatial resolution. We present a two-dimensional fast line-scan approach that enables direct imaging of neuronal activity with millisecond precision while retaining the high spatial resolution of magnetic resonance imaging (MRI). This approach was demonstrated through in vivo mouse brain imaging at 9.4 tesla during electrical whisker-pad stimulation. In vivo spike recording and optogenetics confirmed the high correlation of the observed MRI signal with neural activity. It also captured the sequential and laminar-specific propagation of neuronal activity along the thalamocortical pathway. This high-resolution, direct imaging of neuronal activity will open up new avenues in brain science by providing a deeper understanding of the brain’s functional organization, including the temporospatial dynamics of neural networks.
Covalent organic framework–based porous ionomers for high-performance fuel cells
Authors: Zhang Qingnuan , Dong Shuda , Shao Pengpeng , Zhu Yuhao , Mu Zhenjie , Sheng Dafei , Zhang Teng , Jiang Xin , Shao Ruiwen , Ren Zhixin , Xie Jing , Feng Xiao , Wang Bo
Published: October 2022

Lowering platinum (Pt) loadings without sacrificing power density and durability in fuel cells is highly desired yet challenging because of the high mass transport resistance near the catalyst surfaces. We tailored the three-phase microenvironment by optimizing the ionomer by incorporating ionic covalent organic framework (COF) nanosheets into Nafion. The mesoporous apertures of 2.8 to 4.1 nanometers and appendant sulfonate groups enabled the proton transfer and promoted oxygen permeation. The mass activity of Pt and the peak power density of the fuel cell with Pt/Vulcan (0.07 mg of Pt per square centimeter in the cathode) both reached 1.6 times those values without the COF. This strategy was applied to catalyst layers with various Pt loadings and different commercial catalysts.
Simultaneous electrical and thermal rectification in a monolayer lateral heterojunction
Authors: Zhang Yufeng , Lv Qian , Wang Haidong , Zhao Shuaiyi , Xiong Qihua , Lv Ruitao , Zhang Xing
Published: October 2022

Efficient waste heat dissipation has become increasingly challenging as transistor size has decreased to nanometers. As governed by universal Umklapp phonon scattering, the thermal conductivity of semiconductors decreases at higher temperatures and causes heat transfer deterioration under high-power conditions. In this study, we realized simultaneous electrical and thermal rectification (TR) in a monolayer MoSe
2
-WSe
2
lateral heterostructure. The atomically thin MoSe
2
-WSe
2
heterojunction forms an electrical diode with a high ON/OFF ratio up to 10
4
. Meanwhile, a preferred heat dissipation channel was formed from MoSe
2
to WSe
2
in the ON state of the heterojunction diode at high bias voltage with a TR factor as high as 96%. Higher thermal conductivity was achieved at higher temperatures owing to the TR effect caused by the local temperature gradient. Furthermore, the TR factor could be regulated from maximum to zero by rotating the angle of the monolayer heterojunction interface. This result opens a path for designing novel nanoelectronic devices with enhanced thermal dissipation.
Recycling plastic using a hybrid process
Authors: Yan Ning
Published: October 2022

Integrating oxidation and bioconversion provides a solution to recycle mixed plastics
Hydrogen power gets a boost
Authors: Ma Ting , Lutkenhaus Jodie L.
Published: October 2022

A fuel cell gains more power from ion-conducting, porous covalent organic frameworks
A viral arsenal
Authors: Leslie Mitch
Published: October 2022

SARS-CoV-2 wields versatile proteins to foil our immune system’s counterattack
Population Pharmacokinetics/Pharmacodynamics and Clinical Outcomes of Meropenem in Critically Ill Patients
Authors: Boonpeng Apinya , Jaruratanasirikul Sutep , Jullangkoon Monchana , Samaeng Maseetoh , Wattanavijitkul Thitima , Bhurayanontachai Rungsun , Pattharachayakul Sutthiporn
Published: October 2022

Several pathophysiological changes can alter meropenem pharmacokinetics in critically ill patients, thereby increasing the risk of subtherapeutic concentrations and affecting therapeutic outcomes. This study aimed to characterize the population pharmacokinetic (PPK) parameters of meropenem, evaluate the relationship between the pharmacokinetic/pharmacodynamic index of meropenem and treatment outcomes, and evaluate the different dosage regimens that can achieve 40%, 75%, and 100% of the dosing interval for which the free plasma concentrations remain above the MIC of the pathogens (
fT
>MIC
) targets.
Functional Activities of O-Polysaccharide and Hemolysin Coregulated Protein 1 Specific Antibodies Isolated from Melioidosis Patients
Authors: Pumpuang Apinya , Paksanont Suporn , Burtnick Mary N. , Brett Paul J. , Chantratita Narisara
Published: October 2022

Melioidosis is a fatal tropical disease caused by the environmental Gram-negative bacterium,Burkholderia pseudomallei. This bacterium is intrinsically resistant to several antibiotics and treatment of melioidosis requires prolonged antibiotic administration.
Identification of Attenuators of Transcriptional Termination: Implications for RNA Regulation in Escherichia coli
Authors: Morita Teppei , Majdalani Nadim , Miura Masahiro C. , Inose Rerina , Oshima Taku , Tomita Masaru , Kanai Akio , Gottesman Susan
Published: October 2022

Growing evidence suggests that the modulation of intrinsic termination and readthrough of transcription is more widespread than previously appreciated. For small RNAs, proper termination plays a critical role in their regulatory function.
Draft Genome Sequence of Cronobacter sakazakii H05, Sequence Type 156, Isolated from a Spiced Ground Beef Dish, Kitfo
Authors: Eshetea Behailu B. , Beaubrun Junia Jean-Gilles , Mashraqi Abdullah , Eribo Broderick
Published: October 2022

Cronobacter sakazakii
is a foodborne pathogen that causes severe illness in neonates and the elderly. Here, we present the genome sequence of
C. sakazakii
H05 sequence type 156 (ST156), CC21 strain from Kitfo, resulting in a genome size of 4,495,386 bp, with 4,340 coding sequences and a G+C content of 56.85% after assembly and annotation.
Complete Genome Sequences of Two
Rhizobium
Strains Producing Azol(in)e-Modified Antibiotics
Authors: Travin Dmitrii Y. , Sutormin Dmitry , Mergaert Peter , Severinov Konstantin
Published: October 2022

Rhizobia are known for their ability to establish symbiotic relationships with plants. The specialized metabolism of these bacteria remains understudied. Here, we report whole-genome sequences of two rhizobia producing narrow-spectrum antirhizobial azol(in)e-modified peptides: that of
Rhizobium
sp. Pop5, a phazolicin producer, and another of
Rhizobium anhuiense
T24, a trifolitoxin producer.
Complete Genome Sequence of a New Zealand Mycobacterium tuberculosis Strain Responsible for Ongoing Transmission over the Past 30 Years
Authors: Mulholland Claire V. , Gimenez Gregory , Williamson Adele , Steele Mackenzie , Thorpe Duncan , Karalus Noel , Cursons Ray T. , Playle Veronica M. , Roberts Sally A. , Cook Gregory M. , Arcus Vickery L. , Aung Htin Lin
Published: October 2022

We report here the complete genome sequence of
Mycobacterium tuberculosis
strain Colonial S-type 1 (CS1), which has been responsible for ongoing outbreaks of tuberculosis in New Zealand over the past 30 years. CS1 appears to be highly transmissible, with greater rates of progression to active disease, compared to other circulating
M. tuberculosis
strains; therefore, comparison of its genomic content is of interest.
Genome Sequences of Microbacterium foliorum Phages Anseraureola, Pondwater, and Yasuo
Authors: Bamgbowu David , Bsoumai John , Butura Jessica , Cady Emma , Cholod Gabriella , Collibee Isaac , Dompreh Lois , Eisner Sydney , Elmaleh Maxim , Fitzgerald Katelan , Gillis Eric , Horgan Anna , Judd Dylan , Keefe Julia , Kovalski Erika , LaBianca Kylie , Lee Patrick , Lin Fengkai , Maiuri Heather , McDonald Chloe , McKnight Arden , Meseerole Meghan , Mizra Farah , Monger Elizabeth , Moore Evelyn , Nguyen Nina , Noel Bettina , O’Connor Daniel , Pagani Ruben , Palmgren Makenzie , Pan Karin , Pech Bondita , Qian Jeanne , Rastegar Sheida , Simas Brittney , Southard Adeline , Tracy Matt , Vuong Harry , Whelan Sean , Zou Angela , Punska Elizabeth , Pause Robert , Zhang Fengqiu , Ribbe Alexander , Chien Peter , Rocheleau Jessica
Published: October 2022

Anseraureola, Pondwater, and Yasuo are bacteriophages with siphovirus morphology that infect
Microbacterium foliorum
NRRL B-24224. They were isolated from soil collected in Amherst, Massachusetts, and have genome lengths between 17,362 bp and 17,453 bp. These phages each contain 25 predicted protein-coding genes and are assigned to phage cluster EE.
Draft Genome Sequences for 6 Isolates of Endospore-Forming Class
Bacilli
Species Isolated from Soil from a Suburban, Wooded, Developed Space
Authors: McLoon Anna L. , Awad Thomas T. , Bogardus Molly F. , Buono Meredith G. , Devine Kaitlyn A. , Draper Rebecca M. , Femenella Brianna , Gallagher Hannah M. , Morelock Laura A. , Razi Mishal , Rennick Jacqueline R. , Sheridan Abigail K. , Thibault Righlee J. , Touchette Katie L. , Zuchowski Grace E.
Published: October 2022

Here, we report draft genome sequences of
Bacillus pseudomycoides
SC107,
Rossellomorea
sp. SC111,
Peribacillus frigoritolerans
SC112,
Priestia megaterium
SC114,
Paenibacillus
sp. SC116, and
Lysinibacillus fusiformis
SC117, isolated from a campus wooded area in Loudonville, NY. Genomes were sequenced using the Illumina NextSeq system. The genomes range between 4,381,526 and 6,065,181 bp with GC contents between 35.33% and 43.46%.
Multiple T6SSs, Mobile Auxiliary Modules, and Effectors Revealed in a Systematic Analysis of the Vibrio parahaemolyticus Pan-Genome
Authors: Jana Biswanath , Keppel Kinga , Fridman Chaya Mushka , Bosis Eran , Salomon Dor
Published: October 2022

Gram-negative bacteria employ toxin delivery systems to mediate their interactions with neighboring cells.
Vibrio parahaemolyticus
, an emerging pathogen of humans and marine animals, was shown to deploy antibacterial toxins into competing bacteria via the type VI secretion system (T6SS). Here, we analyzed 1,727
V. parahaemolyticus
genomes and revealed the pan-genome T6SS repertoire of this species, including the T6SS gene clusters, horizontally shared auxiliary modules, and toxins.
Acinetobacter nosocomialis Causes as Severe Disease as Acinetobacter baumannii in Northeast Thailand: Underestimated Role of A. nosocomialis in Infection
Authors: Nithichanon Arnone , Kewcharoenwong Chidchamai , Da-oh Hudadini , Surajinda Sirithorn , Khongmee Aranya , Koosakunwat Surathinee , Wren Brendan W. , Stabler Richard A. , Brown Jeremy S. , Lertmemongkolchai Ganjana
Published: October 2022

Bacterial infections by
Acinetobacter
species are global threats due to their severity and high levels of antibiotic resistance.
A. baumannii
is the most common pathogen in the genus; however, infection by
A. nosocomialis
has also been widely reported but is thought to be less severe. In this study, we have prospectively investigated 48 reported cases of
A. baumannii
infection in Northeast Thailand, and characterized the serological responses to infection.