Vessel System Research Articles

A rapid globe-wide shortest route planning algorithm based on two-layer oceanic shortcut network considering great circle distance

In this paper, to realize the globe-wide route planning in a real-time by graph-search, we put forward an oceanic shortcut network (OSN) to discretize the large planning area involved, which consists of a base graph to resolve tiny features and a fast-forwarding graph to accelerate searching process. Then, A* graph-search is applied on the proposed OSN to derive a shortest path between given starting and end points, which is applicable in the dispatching system for vessels. Noticeably, since the shortcuts have arbitrary heading directions, our algorithm does not have angular bias problem as the conventional structured-grids and can follow optimal routes with proper headings. Moreover, when building the OSN, instead of Euclidean distance (ED), we apply the great circle distance (GCD) in the distance metric for both layers, which can approximate the distance on a spherical surface accurately. Additionally, during the construction of OSN, we propose a method to determine if a point is in the obstacle and judge if a line segment has intersections with the obstacle on a spherical surface. Lastly, we testify our algorithm in several cases to demonstrate the total-distance reduction and time-efficiency brought by it.

Evaluation and optimization of an engine waste heat assisted Carnot battery system for ocean-going vessels during harbor stays

The pollution and environmental damage caused by ship emissions during docking is an urgent issues that needs to be addressed. In this study, a jacket water waste heat Carnot battery (JCB) system is designed as an energy storage device to recover the water waste heat of the ship's main engine cylinder liner and as a power output device when the main engine stops in port. The JCB system is evaluated and optimized from the perspectives of thermodynamics, exergy, and cost, with a focus on the performance under different working fluid combinations. The results show that improving the efficiency of the compressor, turbine, and recuperator can significantly enhance the system's performance, with the compressor and turbine being the most expensive components. The heat exchanger has the highest exergy destruction, accounting for almost half of the total system. In the multi-objective optimization of different working fluid combinations, R365mfc/R365mfc is found to be the best choice, with the power-to-power efficiency of the system reaching 110.15 % and the 5-year levelized cost of storage (LCOS) being 0.139 $/kWh. A case study of the actual route shows that the JCB system designed in this paper can meet the power demand of 100 %, 35.5 %, 61.91 %, and 56.9 % in the four segments during harbor stays. The JCB system proposed in this study provides a new solution for the reduction of emissions and environmental protection during the docking of ships.

WATCH VIDEO ABSTRACT: Dermatoporosis: Strategies for Rebuilding the Extracellular Matrix of the Skin.

Dermatoporosis as a disease entity is relatively newly described, the title conceived as recently as 2007. The background of chronic skin fragility, bruising, and atrophy appears to start in some patients as early as their mid-forties, but is full blown over the age of 65 years. The dehydration and fragility of the skin with recurrent bruising and breakdown were initially attributed to increased vessel fragility and permeability thought to be associated with inherent vascular tissue defects in a milieu of increased inflammation and extracellular matrix (ECM) degradation. It has subsequently been demonstrated that this ECM breakdown directly affects the structural support system of the superficial vessels, leading to stretch, increased permeability, and vulnerability to mechanical damage. Add to that the ECM atrophy and general accumulation of non-functional metabolic waste products in the form of fragmented collagen, elastin, and increased circulating glycation end products, and it becomes apparent that much of the problem resides in a structural defect, non-functioning, dehydrated, senescent cellular matrix and unsupported vascular system that presents as dermatoporotic characteristics. This paper describes a strategy of ECM replacement to counteract these foundational deficiencies. J Drugs Dermatol. 2023;22(9): doi:10.36849/JDD.7549.

Framework for Designing Reliable Propulsion Systems of Manned-autonomous Vessels

Framework for Designing Reliable Propulsion Systems of Manned-autonomous Vessels

Event-Triggered Adaptive Neural Network Trajectory Tracking Control For Underactuated Ships Under Uncertain Disturbance

Abstract An adaptive neural network (NN) event-triggered trajectory tracking control scheme based on finite time convergence is proposed to address the problem of trajectory tracking control of underdriven surface ships. In this scheme, both NNs and minimum learning parameters (MLPS) are applied. The internal and external uncertainties are approximated by NNs. To reduce the computational complexity, MLPs are used in the proposed controller. An event-triggered technique is then incorporated into the control design to synthesise an adaptive NN-based event-triggered controller with finite-time convergence. Lyapunov theory is applied to prove that all signals are bounded in the tracking system of underactuated vessels, and to show that Zeno behavior can be avoided. The validity of this control scheme is determined based on simulation results, and comparisons with some alternative schemes are presented.

Abstraction Refinement for Attractivity Controllers Using Quantitative Synthesis

Attractivity specifications consist in driving the state of a system to a target region and to keep it in that region afterwards. In this paper, we develop an approach to controller synthesis for attractivity specifications based on iterative refinements of symbolic abstractions. We compute iteratively sequences of least-violating attractivity controllers and of associated attractors. The current controller is used to restrict possible control actions at the next iteration where a new abstraction is used following a local refinement applied inside the current attractor. The approach results in a nested sequence of attractors which are closer to the target region at each iteration. To illustrate the effectiveness of our approach, we show an application to a marine vessel system.

О математической модели и схеме замещения трансформатора (критический анализ общепринятой теории)

The article considers the importance of studying the mathematical model and equivalent circuit of the transformer due to the fact that transformers are the most important link in any electric power system, including control and operation systems for marine fishing and transport vessels and stationary marine technological complexes. The generally accepted theory of transformers is analyzed, and erroneous conclusions and statements complicating, and in some cases distorting the essence and interconnection of electromagnetic interactions in the device, are pointed out. In particular, the introduction of voltage into the Kirchhoff equation for the secondary winding Ů2, along with the presence of EMF in it Ė2, creates the illusion that the secondary winding of the transformer has its own independent power source. This illusion is enhanced by the physical and logical scheme, clearly indicating that Ů2, being in the load zone, it generates a current İ2. In fact, the declarative statement that the magnetic fluxes of the primary and secondary windings are connected in coordination is also erroneous. This leads to a number of erroneous conclusions. The exclusion from the mathematical model of magnetic fluxes induced by winding currents isolated from each other does not allow one to analyze the influence of electromagnetic processes in the secondary winding on the processes in the primary. These and a number of other provisions and conclusions in the generally accepted theory necessitate its critical analysis and exclusion. There are proposed different from the generally accepted approaches to the formation of a mathematical model and equivalent circuit of transformers, which lead to their significant composition and content.

Comparison of the 3D-microstructure of human alveolar and fibula bone in microvascular autologous bone transplantation: a synchrotron radiation μ-CT study.

Introduction: Autologous bone transplantation is successfully used in reconstructive surgery of large/critical-sized bone defects, whereby the microvascular free fibula flap is still regarded as the gold standard for the reconstruction of such defects in the head and neck region. Here, we report the morphological and lacunar properties of patient-paired bone samples from eight patients from the jaw (AB; recipient site) and the fibula (FB; donor site) on the micron length-scale using Synchrotron µ-CT. Insights into differences and similarities between these bone structures could offer a better understanding of the underlying mechanism for successful surgical outcomes and might clear the path for optimized, nature-inspired bone scaffold designs. Methods: Spatial vessel-pore arrangements, bone morphology, fluid-simulation derived permeability tensor, osteocyte lacunar density, and lacunar morphology are compared. Results: The orientation of the vessel system indicates a homogenous vessel orientation for AB and FB. The average mineral distance (50%) to the closest vessel boundary is higher in AB than in FB (the mean is 96μm for AB vs. 76μm for FB; p = 0.021). Average osteocyte lacunar density is found to be higher in AB than in FB (mean 22,874mm3 vs. 19,376mm3 for FB; p = 0.038), which might compensate for the high distance from the mineral to the nearest vessel. No significant differences in lacunar volume are found between paired AB and FB. Discussion: A comparable vessel network and similar distribution of vessel porosity between AB and FB may allow the FB graft to exhibit a high regeneration potential when connected to AB, and this might correlate with a high osteoinductive and osteoconductive potential of FB when connected to AB. Since widely used and potent synthetic bone grafts exist, new insight into the bone structure of well-established autologous bone grafts, such as the free fibula flap, could help to improve the performance of such materials and therefore the design of 3D scaffolds.

Changes in the Hemostasis System in Children with Hemorrhagic Vasculitis (Henoch-Schönlein purpura)

The article discusses changes in the hemostasis system in children with hemorrhagic vasculitis, in particular, damage to the walls of small vessels by immune complexes circulating in the circulatory system and activated components of the complement system, and then activation of all parts of the hemostasis system, as well as changes in the hemostasis system of blood vessels, platelets, plasma. Hemorrhagic vasculitis (IgAV) is classically a childhood disease with an incidence of about 10 cases per 100,000 a year. The pediatric form of this pathology is generally considered benign and self-limited. In contrast, IgAV in adults is less common but often associated with worse clinical course and outcome The results of studies conducted by different authors in different countries on the study of the processes of violation of the mechanisms of blood coagulation in hemorrhagic vasculitis in children are presented.

Fixed-Time Formation Tracking Control of Multiple Unmanned Surface Vessels Considering Lumped Disturbances and Input Saturation

This paper investigates the challenging problem of fixed-time formation trajectory tracking control for multiple unmanned surface vessels (USVs) affected by uncertain model dynamics, time-varying external ocean disturbances, as well as input saturation. Firstly, an adaptive super-twisting lumped disturbance observer (ASTLDO) is created by integrating high-order sliding mode with observer technology, which can accurately observe and compensate for the complex disturbance of the system within a finite time. Secondly, following the disturbance observer, backstepping technique, fixed-time control, and virtual leader–follower algorithm, the fixed-time formation tracking strategy is implemented. The proposed formation tracking control scheme enables the multiple surface vessels system to converge and maintain a stable desired formation in a fixed time, and the convergence time is independent of the initial states of the system. Furthermore, an adaptive auxiliary system is introduced to mitigate input saturation. In the end, the effectiveness and anti-interference ability of the suggested approach are confirmed by the formation simulation results of three USVs.

Quantum Dot Biomimetic for SARS-CoV-2 to Interrogate Blood-Brain Barrier Damage Relevant to NeuroCOVID Brain Inflammation.

Despite limited evidence for infection of SARS-CoV-2 in the central nervous system, cognitive impairment is a common complication reported in "recovered" COVID-19 patients. Identification of the origins of these neurological impairments is essential to inform therapeutic designs against them. However, such studies are limited, in part, by the current status of high-fidelity probes to visually investigate the effects of SARS-CoV-2 on the system of blood vessels and nerve cells in the brain, called the neurovascular unit. Here, we report that nanocrystal quantum dot micelles decorated with spike protein (COVID-QDs) are able to interrogate neurological damage due to SARS-CoV-2. In a transwell co-culture model of the neurovascular unit, exposure of brain endothelial cells to COVID-QDs elicited an inflammatory response in neurons and astrocytes without direct interaction with the COVID-QDs. These results provide compelling evidence of an inflammatory response without direct exposure to SARS-CoV-2-like nanoparticles. Additionally, we found that pretreatment with a neuro-protective molecule prevented endothelial cell damage resulting in substantial neurological protection. These results will accelerate studies into the mechanisms by which SARS-CoV-2 mediates neurologic dysfunction.

Energy loss assessment of a two-stage pump under natural flow in the marine cooling system based on entropy production theory

Natural flow conditions are commonly used in the cooling systems of modern high-speed vessels and nuclear submarines. When the vessel's speed satisfies the requirements, it relies on its kinetic energy to supply seawater to the condenser in the cooling system. Under natural flow conditions, the pump is not driven, and the rotor will be “stuck” or rotated passively by the inlet flow shock. The local energy loss caused by the blade tip leakage vortex, surface separation flow, and wake flow significantly impact the system’s performance. Entropy production is an irreversible dissipation effect caused by the energy transfer process. According to the second law of thermodynamics, the entropy production theory can effectively characterize the intensity of local energy loss under natural flow conditions. In this study, the variation law of hydraulic loss and passive rotational speed under different flow rates of a two-stage pump were obtained by natural flow experiments. Moreover, the generation mechanism of intense energy loss under different natural flow conditions was investigated based on computational fluid dynamics (CFD) and entropy production theory. The results show that the entropy production induced by turbulent kinetic energy (TEP) is dominant, averaging 71.8%, followed by the wall entropy production (WEP), about 26.1%. The contribution of viscous dissipation entropy production (VDEP) can be negligible. When the impeller is “stuck” at low flow rates, entropy production is mainly from the flow separation near the blade and the flow shock region close to the guide vane back. The total entropy production of the guide vane accounts for 78%, higher than the impeller. However, when the impeller rotates passively at high flow rates, the energy loss inside the impeller is dominant, about 62%. The energy loss occurs around the blade wake region and the high velocity-gradient region near the guide vane. The flow field patterns between the two stages are similar, but the energy loss in the impeller and guide vane of stage Ⅱ is much higher. The TEP and WEP of the two impeller stages differed by 14% and 10%, respectively, and the guide vane of the two stages differed by 8% and 3%, at a flow rate of 196.8 m3/h.

Time-Synchronized Control for an Uncertain Marine Vessel System With External Disturbance

In this paper, we focus on the tracking control problem of the unmanned marine vessel (UMV) system with uncertainty and external disturbance. In order to resist the adverse effect on each other between the UMV system states, a time-synchronized control method is proposed to handle the coupling problem, which can guarantee that all system states can achieve the convergence at the same time. In the control design, a time-synchronized estimator is designed to handle the problems of system uncertainty and external disturbance. Furthermore, the stability analysis of the UMV system is given to prove the feasibility of the proposed time-synchronized control. Finally, simulations on a practical UMV model are conducted to illustrate the advantages and effectiveness of the proposed time-synchronized control.

Efficiency of fuel gas supply on LNG-fueled vessels

The widespread use of LNG as a fuel for marine internal combustion engines makes to pay attention to the quality of gas fuel supply systems and its specifics. The objective of this paper is to review modern gas fuel supply systems and analyze their efficiency. The goal is to determine the most important parameters of gas fuel that affect the stability of the working process of marine dual-fuel engines and ways to maintain them within the specified limits. Evaluation of the gas fuel preparation efficiency is carried out on the basis of operational data obtained on the gas carrier vessel board. Data collection is carried out under non-standard operating conditions, which makes it possible to evaluate the quality of the resulting gas fuel with a time-varying composition of the initial natural gas. To analyze the obtained data, modern software, which is used by leading developers of marine diesel engines, is used (Wartsila Methane Number Calculator, AVL BoostTM and Python 3 statistic libraries). The analysis results are approximated for gas fuel supply systems for gas-fueled vessels, but not being gas carriers. This approximation is made taking into account the design features of gas fuel supply systems, since the specificity of the design imposes certain restrictions on the applicability of the conclusions obtained as a result of the previous analysis. Also, attention is paid to the accumulation of residual heavy hydrocarbons in bunker tanks, the excess of which can adversely affect the quality of gas fuel. Since there is no universal way to solve this problem, only general assumptions about possible ways to dispose of them have been made.

Investigation of Temperature Cycling with Coupled Vessels for Efficient Deracemization of NMPA.

Chiral compounds can exist as pairs of nonsuperimposable stereoisomers (enantiomers) possessing the same physical properties but interacting differently with biological systems. This makes them interesting materials to be explored by the pharmaceutical and food industries. In this study, to obtain pure enantiomers from their conglomerates, a method that involves using a two-vessel system for deracemization of N-(2-methylbenzylidene) phenylglycine amide (NMPA) was developed. In this method, a suspension was transferred with a pulsating pumping profile between two inter-connected stirred vessels that were set at constant temperatures. As the suspension was exposed to more rapid changes in temperature, it resulted in the speeding up of the process and thus enhancing productivity in comparison to a single vessel system. The results confirmed successful deracemization of NMPA. A modified pumping profile and tubing design eliminated the issue of clogging of the transfer tubes and ensured effective suspension transfer for longer durations. Operating parameters, such as initial enantiomeric excess, vessel residence time, and suspension density were also investigated. In this method, optimization of residence time was necessary to enhance the efficiency of the process further. Results confirmed that this methodology has the potential to be more adaptable and scalable as it involved no mechanical attrition.

The Null technique as a novel, potential first-line method of device delivery for complicated lesions during percutaneous coronary intervention

AimDuring percutaneous coronary intervention (PCI), complicated lesions in the target coronary artery often hinder device delivery. Fluid lubricants have commonly been used to reduce friction between adjacent solid materials in manufacturing, thus achieving smoother action. This ex vivo experimental study examined whether a contrast medium could function as a fluid lubricant during PCI. Methods and resultsWe used two different coronary artery lesion models with distinct complexities made from silicon. Each model was fit into the ex vivo PCI-simulation system. This ex vivo laboratory equipment consisted of ordinary PCI instruments and an aorta model from the Valsalva sinus to the descending aorta. A Wolverine™ cutting balloon catheter was advanced through each lesion model via a guide catheter set into the system. The maximum force required to push the catheter through the lesion models was measured while the vessel system was filled with either normal saline or contrast medium. The maximum force required was significantly lower with the contrast medium (1.38 ± 0.21 N in the normal-saline condition vs. 0.92 ± 0.05 N in the contrast-medium condition in the lesion model A, p < 0.001; 1.30 ± 0.07 N in the normal-saline condition vs. 1.14 ± 0.04 N in the contrast-medium condition in the lesion model B, p < 0.001). ConclusionsThe contrast medium for vessel system filling reduced the force required to push the devices through the lesion models. This contrast medium represents a potential candidate for a liquid lubricant to facilitate device delivery for complicated coronary lesions.

Effect of Long-Term Aging on Fatigue and Thermal Cracking Performance of Polyphosphoric Acid and Styrene-Butadiene-Styrene-Modified Bio-Blend Bitumen.

Polyphosphoric acid (PPA) and styrene-butadiene-styrene (SBS) were adopted to produce PPA-SBS-modified bio-blend bitumen, which achieved excellent mechanical performance. However, its long-range performance, such as the fatigue and thermal cracking behavior under long-term thermal oxidation, is not well understood. Therefore, a pressure aging vessel (PAV) system was applied to simulate the aging behavior of the bitumen under the action of thermal oxidation. Then, a linear amplitude sweep (LAS) test combined with a viscoelastic continuum damage (VECD) model was applied to investigate the fatigue properties of the bitumen. Moreover, a bending beam rheometer (BBR) test was conducted to evaluate the thermal cracking resistance of the bitumen before and after PAV aging. Meanwhile, an atomic force microscope (AFM) was applied to observe the microscopic topography. The results show that the original compound-modified bitumen can bear more fatigue damage than that of the control bitumen at the failure point, and it also has excellent fatigue resistance at 2.5%, 5%, 7.5%, and 10% applied strain. Moreover, the VECD model can accurately predict the fatigue life of the bitumen under different applied strains. The variation ratio of stiffness modulus for the compound-modified bitumen is below that of the control bitumen after PAV aging, so it shows a better anti-aging performance. Finally, the AFM test shows that PPA and bio-bitumen decrease the heterogeneity of the bitumen, reducing the difference between phases.

Optimizing Load Frequency Control in Standalone Marine Microgrids Using Meta-Heuristic Techniques

Integrating renewable resources into the electrical systems of marine vessels achieves the dual goal of diversifying energy resources and reducing greenhouse gas emissions. The presence of intermittent renewable sources and sudden nonlinear load changes can cause frequency deviations in isolated hybrid marine microgrids. To address this issue, the paper proposes a conventional PID (proportional–integral–derivative)-controller-based LFC (load frequency controller) which is optimized by meta-heuristic optimization algorithms, namely, PSO (particle swarm optimization), GWO (grey wolf optimization) and hybrid PSO-GWO. The proposed LFC was designed using transfer functions of various microgrid components, with ITAE (integral time absolute error) and ITSE (integral time square error) serving as performance indices. The proposed LFC’s validation was performed through HIL (hardware-in-loop) real-time simulation using a DS 1104 R&amp;D controller board, with simulation results showing the better performance of the optimized frequency response compared to the nonoptimized LFC controller in terms of rise time, fall time, slew rate and overshoot. The hybrid PSO-GWO algorithm performs better than the other optimization algorithms. The simulation results demonstrate the stability and robustness of the proposed controller. In summary, the proposed PID-controller-based LFC can regulate frequency deviation in standalone hybrid marine microgrids effectively.

Solid Oxide Fuel Cells for Marine Applications

The marine industry must reduce emissions to comply with recent and future regulations. Solid oxide fuel cells (SOFCs) are seen as a promising option for efficient power generation on ships with reduced emissions. However, it is unclear how the devices can be integrated and how this affects the operation of the ship economically and environmentally. This paper reviews studies that consider SOFC for marine applications. First, this article discusses noteworthy developments in SOFC systems, including power plant options and fuel possibilities. Next, it presents the design drivers for a marine power plant and explores how an SOFC system performs. Hereafter, the possibilities for integrating the SOFC system with the ship are examined, also considering economic and environmental impact. The review shows unexplored potential to successfully integrate SOFC with thermal and electrical systems in marine vessels. Additionally, it is identified that there are still possibilities to improve marine SOFC systems, for which a holistic approach is needed for design at cell, stack, module, and system level. Nevertheless, it is expected that hybridisation is needed for a technically and economically feasible ship. Despite its high cost, SOFC systems could significantly reduce GHG, NOX, SOX, PM, and noise emissions in shipping.

Development of vessel mimicking microfluidic device for studying mechano-response of endothelial cells

The objective of this study is to develop a device to mimic a microfluidic system of human arterial blood vessels. The device combines fluid shear stress (FSS) and cyclic stretch (CS), which are resulting from blood flow and blood pressure, respectively. The device can reveal real-time observation of dynamic morphological change of cells in different flow fields (continuous flow, reciprocating flow and pulsatile flow) and stretch. We observe the effects of FSS and CS on endothelial cells (ECs), including ECs align their cytoskeleton proteins with the fluid flow direction and paxillin redistribution to the cell periphery or the end of stress fibers. Thus, understanding the morphological and functional changes of endothelial cells on physical stimuli can help us to prevent and improve the treatment of cardiovascular diseases.