bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrosylation of cardiac CaMKII at Cys290 mediates mechanical afterload‐induced increases in Ca2+ transient and Ca2+ sparks
Authors: Alim Chidera C. , Ko Christopher Y. , Mira Hernandez Juliana , Shen Erin Y. , Baidar Sonya , Chen‐Izu Ye , Bers Donald M. , Bossuyt Julie 
Published: October 2022

AbstractCardiac mechanical afterload induces an intrinsic autoregulatory increase in myocyte Ca2+ dynamics and contractility to enhance contraction (known as the Anrep effect or slow force response). Our prior work has implicated both nitric oxide (NO) produced by NO synthase 1 (NOS1) and calcium/calmodulin‐dependent protein kinase II (CaMKII) activity as required mediators of this form of mechano‐chemo‐transduction. To test whether a single S‐nitrosylation site on CaMKIIδ (Cys290) mediates enhanced sarcoplasmic reticulum Ca2+ leak and afterload‐induced increases in sarcoplasmic reticulum (SR) Ca2+ uptake and release, we created a novel CRISPR‐based CaMKIIδ knock‐in (KI) mouse with a Cys to Ala mutation at C290. These CaMKIIδ‐C290A‐KI mice exhibited normal cardiac morphometry and function, as well as basal myocyte Ca2+ transients (CaTs) and β‐adrenergic responses. However, the NO donor S‐nitrosoglutathione caused an acute increased Ca2+ spark frequency in wild‐type (WT) myocytes that was absent in the CaMKIIδ‐C290A‐KI myocytes. Using our cell‐in‐gel system to exert multiaxial three‐dimensional mechanical afterload on myocytes during contraction, we found that WT myocytes exhibited an afterload‐induced increase in Ca2+ sparks and Ca2+ transient amplitude and rate of decline. These afterload‐induced effects were prevented in both cardiac‐specific CaMKIIδ knockout and point mutant CaMKIIδ‐C290A‐KI myocytes. We conclude that CaMKIIδ activation by S‐nitrosylation at the C290 site is essential in mediating the intrinsic afterload‐induced enhancement of myocyte SR Ca2+ uptake, release and Ca2+ transient amplitude (the Anrep effect). The data also indicate that NOS1 activation is upstream of S‐nitrosylation at C290 of CaMKII, and that this molecular mechano‐chemo‐transduction pathway is beneficial in allowing the heart to increase contractility to limit the reduction in stroke volume when aortic pressure (afterload) is elevated.
imageKey points
A novel CRISPR‐based CaMKIIδ knock‐in mouse was created in which kinase activation by S‐nitrosylation at Cys290 (C290A) is prevented.
How afterload affects Ca2+ signalling was measured in cardiac myocytes that were embedded in a hydrogel that imposes a three‐dimensional afterload.
This mechanical afterload induced an increase in Ca2+ transient amplitude and decay in wild‐type myocytes, but not in cardiac‐specific CaMKIIδ knockout or C290A knock‐in myocytes.
The CaMKIIδ‐C290 S‐nitrosylation site is essential for the afterload‐induced enhancement of Ca2+ transient amplitude and Ca2+ sparks.
Joint Optimization of Maintenance and Spare Parts Inventory for Multi-Unit Systems With a Generalized Structure
Authors: Yan Tao , Lei Yaguo , Li Naipeng , Pintelon Liliane , Dewil Reginald 
Published: October 2022

Abstract
Joint optimization of maintenance operations and spare parts inventory is promising for ensuring the reliable and efficient operation of industrial systems. Extensive studies have been conducted on joint optimization emphasizing various aspects. However, those studies still suffer two limitations. (1) The considered system structures are restricted to particular cases, and thus are unable to fully address the joint optimization needs of actual industrial systems possessing various structures, and (2) imperfect maintenance, as has been commonly adopted in industries, is not addressed in existing works, which compromises the economic efficiency of the joint policy. Targeted at these limitations, this paper investigates the joint optimization for multi-unit systems with a generalized structure, i.e., the systems consist of multiple identical units, and each unit possesses a complex subsystem structure. First, a total cost rate model is formulated, in which maintenance actions include both perfect replacement and imperfect maintenance, and the spare parts inventory policy consists of an (s, S) policy and the option to place emergency orders. Based on the formulated model, a simulation optimization method is proposed. The simulation module evaluates the total cost rate iteratively, and the optimization module utilizes a variable neighborhood search-based algorithm to obtain a high-quality joint policy with tractable computation times. Two numerical examples are provided for demonstration, and sensitivity analyses are conducted to study the effects of parameters.
Pareto Optimal and Dual-Objective Geometric and Structural Design of an Underwater Kite for Closed-Loop Flight Performance
Authors: Naik Kartik , Beknalkar Sumedh , Reed James , Mazzoleni Andre , Fathy Hosam , Vermillion Chris 
Published: October 2022

Abstract
This paper presents the formulation and results for a control-aware optimization of the combined geometric and structural design of an energy-harvesting underwater kite. Because kite-based energy-harvesting systems, both airborne and underwater, possess strong coupling between closed-loop flight control, geometric design, and structural design, consideration of all three facets of the design within a single codesign framework is highly desirable. However, while prior literature has addressed one or two attributes of the design at a time, this work constitutes the first comprehensive effort aimed at addressing all three. In particular, focusing on the goals of power maximization and mass minimization, we present a codesign formulation that fuses a geometric optimization tool, structural optimization tool, and closed-loop flight efficiency map. The resulting integrated codesign tool is used to address two mathematical optimization formulations that exhibit subtle differences: a Pareto optimal formulation and a dual-objective formulation that focuses on a weighted power-to-mass ratio as the techno-economic metric of merit. Based on the resulting geometric and structural designs, using a mediumfidelity closed-loop simulation tool, the proposed formulation is shown to achieve more than three times the powerto-mass ratio of a previously published, unoptimized benchmark design.
Experimental Study on Dynamic Characteristics of Fluid-Conveying Pipe for OTEC
Authors: Hisamatsu Ryoya , Adiputra Ristiyanto , Utsunomiya Tomoaki 
Published: October 2022

Abstract
A commercial-scale Ocean Thermal Energy Conversion (OTEC) floating plant will be attached a large diameter Cold Water Pipe (CWP). There are concerns about unstable vibration and changes in the dynamic characteristic due to too large mass flow rate. Since the vibration may interfere development of larger capacity plant, comprehending the phenomena have generated considerable interest. The main objective of this study is to confirm whether the theory that describes the vibration of submerged fluid-conveying pipe reproduces the real phenomena through a tank experiment. We construct the experiment eliminated possible disturbances, and the free damping vibration of polycarbonate pipe of 4 m length is measured during water intake. In order to compare the experimental pipe and theoretical models, the damping characteristics are identified from the results without internal flow. As a result of the comparison, although the theoretical model using the inlet end condition reproduces basically reproduced the experiment, we observe a three dimensional nonlinear behavior that could not be predicted by the theory. We believe that this experiment will serve to improve the theories.
Modelling of a Subsea Shuttle Tanker Hovering in Ocean Currents
Authors: Ma Yucong , Xing Yihan , Silva Marina Simplicio Da , Sui Dan 
Published: October 2022

Abstract
A baseline design of subsea shuttle tanker (SST) for liquid carbon dioxide transportation was recently proposed by authors to support studies evaluating the ultra-efficient underwater cargo submarine concept. One important topic is the position keeping ability of SST during the offloading process. When the subsea shuttle tanker is offloading at the storage site, it hovers above the well in the vicinity and connects with the wellhead using a flowline. The entire offloading process takes around four hours. Ocean currents can cause tremendous drag forces on the subsea shuttle tanker during this period. Preliminary studies show that the drag force introduced by the sideways current is over 80 times that of the heading current. Therefore, the SST would current-vane to reduce load effects from currents and maintain its position. During this process, the flow velocities over hydroplanes are low, and the generated lift forces are generally insufficient to maintain the SST’s depth. In the baseline design, compensation tanks are used to maintain the depth when hovering. However, the ballasting and de-ballasting of tanks are generally slow. It is, therefore, envisioned that although it can compensate for the weight change, additional thrusters that can provide actuation with higher frequencies are still required. This paper presents a planar model to study the SST’s vertical position keeping ability in current using its propeller and tunnel thrusters. The ocean current follows a first-order Gauss-Markov process. SST motions are first measured by a Luenberger observer and then delivered to a Linear Quadratic Regulator to calculate the control input. This work facilitates the SST station keeping problem and helps with the design of SST control units. Effects from controller gains and observer gains on the SST motions are discussed. Numerical results show that the designed hovering control system can ensure the SST’s stationary during offloading. Finally, the SST footprints at 0.5 m/s, 1.0 m/s, and 1.5 m/s mean current speed are presented.
Estimation of Still-Water Bending Moment of Ship Hull Girder Using Beam Finite Element Model and Ensemble Kalman Filter
Authors: Tatsumi Akira , Iijima Kazuhiro , Fujikubo Masahiko 
Published: October 2022

Abstract
Longitudinal bending strength is the most fundamental strength of ship hull girders, and longitudinal bending moment acting on hull girders should be accurately monitored to ensure structural safety during ship operations. The longitudinal bending moment classified into still-water bending moment and wave-induced bending moment. This study proposes a data assimilation method to estimate the still water bending moment, and especially focuses on inverse estimation of cargo load. In the proposed method, hull-girder response in still water is simulated by a beam finite element model supported by distributed restoring springs. Nonlinearity of restoring force due to change of hull shape under waterline is considered in the simulation. To assimilate simulation by beam FEM with observed strains, ensemble Kalman filter is implemented in the beam FEM. To validate the proposed data assimilation method, a still-water tank test using a backbone-type hydro-elastically scaled model is conducted. The proposed method is applied to the measured data, and the ballast load is inversely estimated from the bending strains. The estimation accuracy of the ballast load is improved as repeating prediction by beam FEM and filtering by ensemble Kalman filter, and estimated ballast load has good agreement with actual.
Long-Term Mechanical Properties of Barrier Materials for Cementing Operations – Analysis of Morphology and Micro-Structure
Authors: Kamali Mohammadreza , Khalifeh Mahmoud , Saasen Arild , Silva Santos Moreira Paulo Henrique 
Published: October 2022

Abstract
In the oil and gas and geothermal industry, a barrier material is pumped behind the casing to fill the annular gap between the casing and formation/outer casing. After placement, this slurry is solidified rapidly, and it functions to seal the annular space and protects the casing during the lifecycle of the well. In this article, four different barrier materials namely expansive cement, non-cement pozzolan-based material, geopolymer, and thermosetting resin are examined under equal conditions.
The long-term mechanical properties of the candidate materials were tested by measuring uniaxial compressive strength (UCS), tensile strength, and Young’s modulus. These properties were measured at seven different time intervals, from one day to nine months after curing at a bottomhole static temperature of 90 °C and pressure of 170 bars. The change in the mechanical properties was further investigated by using scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) techniques. The results were benchmarked with the properties of the API neat class G cement as non-commercial reference material.
Our results show that the neat class G cement had a consistent behavior in most of the test period, and its UCS was dropped by 23 % after nine months compared to six months. The expansive cement had no significant change in mechanical properties, but the expansive crystal can weaken the structure, especially close to the boundaries with the cement matrix. The pozzolanic material and geopolymer did not develop early strength. The pozzolanic material reached a plateau after seven days, while the geopolymer developed strength up to six months. The thermosetting resin had the highest UCS and tensile strength up to one month, but its mechanical properties were started to deteriorate from seven days after curing.
Dynamic Response of a Generic Self-Elevating Unit in Operation With Hull in Water
Authors: Zhang Chi , Santo Harrif , Cai Minbo , Magee Allan 
Published: October 2022

Abstract
Self-elevating units (SEUs), with a water-tight hull fitted with long support legs and spudcans, are widely used in offshore drilling and operations, as well as offshore wind turbine installations. SEUs are also known as jack-up rigs. A jack-up rig undergoes several stages of operations involving different leg configurations, such as legs retracted, legs suspended in the water, spudcans pre-loaded into the soil, and legs deployed in the seabed with the hull lifted clear above water. The hull and the legs will therefore be subjected to various external environmental actions. Transit operation (when the hull is in water) is only carried out in mild environmental conditions, due to safety concerns. The dynamic response of the SEU in the transit operation is less investigated in contrast to normal operation when the hull is in elevated condition supported by the legs.
In this paper, we investigate the dynamic behavior of a generic (in-house designed) three-legged SEU. The configuration is such that the hull is in the water while the spudcans are secured in the seabed. A nonlinear time-domain model is established for the coupled hull and legs through Cummins’s equation. The hull is assumed as a rigid body with motions in six degrees of freedom, and the hydrodynamic coefficients are calculated from radiation and diffraction analysis. The legs are simplified as lumped mass models with equivalent stiffness value as the prototype, and Morison-type hydrodynamic loads are applied. Various scenarios of boundary conditions are considered, i.e., constant spudcan constraint stiffness, pin, fixed boundary conditions, and incidental cases when up to two spudcans are released while the other is still secured in the seabed. The dynamic responses of the SEU under operating sea conditions are examined. The results are compared to those from the conventional quasi-static analysis where the legs are simplified as linear springs.
It is found that the dynamic response of the SEU with the hull-in-water condition can be as large as that in the elevated condition, despite the much milder sea conditions. The operational limit can be significantly reduced if the resonant motion occurs. These results show the importance of a full coupled dynamic analysis for a rational design of an SEU and may serve to guide operations for mobile offshore drilling units. It is even more crucial for certain SEUs where the hulls are intended to be in the water for a longer period, such as offshore wind turbine installation vessels. It may also allow the transit operations to be performed under slightly more severe conditions by better defining safe operational limits and reducing uncertainty.
Numerical Simulation of Local Scour Around Square Artificial Reef
Authors: Yang Mingda , Tang Yanli , Zhao Fenfang , Xu Shiji , Fang Guangjie 
Published: October 2022

Abstract
Artificial reefs (ARs) are one of the key man-made constructs to restore the offshore fishery resources and recover the ecological environment. However, it is found that many ARs lost their stability and function due to scour. In order to ensure the functional effect of ARs, it is of great significance to study the instability of ARs, like burying caused by scour in different flow conditions. The three-dimensional numerical model established by FLOW-3D is used to study the local scour characteristics around the AR in steady currents. The RANS equations, closed with the RNG k-ε turbulence model, are established for simulating a stable flow field around one AR. The simulation results are compared with previous experimental results and shows good agreement. Then, the effect of the opening number and the incident angles of ARs on the scour characteristics, the equilibrium scour depth and maximum scour volume are investigated. The results indicate that the scour depth and scour volume decrease with the increasing opening number. Moreover, the empirical equations of the effect of the opening number of the AR on the equilibrium scour depth and maximum scour volume are proposed based on the numerical results. The change of the incident angles will affect the change of bed shear stress at the most upstream corner of the AR. The greater bed shear stress results in a more intense scour. This study will provide theoretical support, and practical guidance for the optimized engineering design and construction of ARs.
Analysis of the Experimental Data of Slamming Loads on an LNG Carrier in Abnormal Waves
Authors: Wang Shan , Guedes Soares C. 
Published: October 2022

Abstract
The objective of the paper is to identify slamming characteristics of ships in abnormal waves by analysing the experimental slamming loads for an LNG carrier from the model tests of the ship, which were conducted at the Ocean Engineering Division of the Technical University Berlin at a model scale of 1:70. To validate the experiments, the numerical results from a time domain nonlinear strip theory code are compared with the measurement of the ship motions and vertical bending moment amidships of the LNG carrier in the New Year Wave. The time series of the slamming pressures on different locations (on the bow and stern) obtained in the experiments are analysed and discussed by studying the peaks using the analytical distribution models, namely, Weibull distribution, Generalized Extreme Value distribution and the Gumbel distribution. The extreme values of the pressure peaks obtained using the three distribution models are compared. Discussion is also provided for the results with two different Froude numbers in order to check the effects of the ship speed on the phenomenon.
Random Experimental Uncertainty Analysis on the Model Tests of an LNG Carrier in Extreme Seas
Authors: Wang Shan , Guedes Soares C. 
Published: October 2022

Abstract
The present work aims at assessing the random experimental uncertainties in the response behaviour of an LNG carrier on the model tests that were carried out at the Ocean Engineering Division of the Technical University Berlin at a model scale of 1:70 within the EU project EXTREME SEAS. The response metrics of interest include the heave and pitch motions, vertical bending moments and slamming pressures on the hull. An irregular sea state with a significate wave height of 11.5m and a peak period of 12 s described by JONSWAP spectrum is considered. Based on the times series of the experimental measurements, the peak values of the heave and pitch motions, vertical bending moments and slamming pressures are identified. The extreme value, the average value of the largest 1/10, the average of the largest 1/3 and the mean value of the peaks are calculated. Then the random standard uncertainties on these parameters are calculated as the standard deviation of the metric across the 5 repeated tests, divided by the square root of the number of observations. The uncertainties for different parameters are calculated and compared for two forward speeds of the ship in head waves.
On Common Research Needs for the Next Generation of Floating Support Structures
Authors: Aksnes Vegard , Alsos Hagbart , Bachynski-Polić Erin , Berthelsen Petter Andreas , Delhaye Virgile , Furevik Birgitte R. , Jostad Hans Petter , Kristiansen Trygve , Ommani Babak 
Published: October 2022

Abstract
The world is facing several industrial and societal challenges, such as providing enough renewable energy and enough safe and healthy food as formulated in the United Nations sustainable development goals. Using floating stationary structures, the ocean can contribute to solving several of the challenges. New applications need new types of structures, with which we have limited experience. These support structures will be diverse, but also have essential research needs in common.
Design of novel floating structures need reliable descriptions of the marine environment. This is particularly challenging for semi-sheltered coastal regions, with complex topography and bathymetry. Novel structures are likely to be compliant, modular and/or multi-body, requiring increased understanding and rational models for wave-structure interaction. Structures with sustainable, safe, and cost-efficient use of materials, including untraditional ones, must be developed. Smart, affordable, and reliable mooring systems and anchors for novel applications are necessary for station keeping. Digital solutions connecting the various stages of design and operation, as well as various design disciplines, researchers, and innovators, will be necessary. Sustainability will be an integral part of any new design.
To unlock the potential of novel floating structures, we need to understand the requirements of the applications, as well as the associated technology gaps and knowledge and research needs. This paper highlights research needs for innovation within floating offshore wind, floating solar power plants, novel aquaculture structures, and coastal infrastructure.
Time Domain Prediction of VIV Responses in Oscillatory Flow Conditions
Authors: Wu Jie , Yin Decao , Jin Jingzhe , Lie Halvor , Passano Elizabeth , Sævik Svein , Grytøyr Guttorm , Tognarelli Michael A. , Karunakaran Daniel , Andersen Torgrim , Igland Ragnar 
Published: October 2022

Abstract
Vortex induced vibrations (VIV) may be developed in the sag-bend area of steel catenary risers (SCRs) and lazy wave risers (SLWRs) induced by the top motions. There is lack of reliable tools to predict VIV responses in such oscillatory flow conditions in the riser design. A time-domain VIV load model has been implemented in software VIVANA-TD. This load model adds a vortex shedding force term with a synchronization model to the conventional Morison load formulation. The synchronization model introduces a phase-coupling between the force and response, which effectively captures how the local vortex shedding frequency may increase or decrease to obtain lock-in. This time domain VIV load model makes it possible to account for time-varying flow speed.
In the present study, the vortex shedding process and response characteristics of VIV in oscillatory flow conditions have been reviewed. The capability and limitations of the existing time domain VIV load model have been investigated. The empirical parameters have been derived from model test data. The validation study using the Equinor SCR and Deepstar SLWR test data shows that the predicted maximum fatigue damage is within a factor of 5 compared to the measurement for 85% of the cases. This demonstrates that the present VIVANA-TD can describe the main characteristic of VIV responses in the oscillatory flow conditions.