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In this study, a vertical-axis helical-blade water turbine is innovatively proposed by drawing on the design scheme of the traditional straight-blade turbine, compared to which this blade form can effectively improve the self-starting capability and energy capture efficiency of the turbine. The study analyzes the hydrodynamic performance of the device under different parameters using CFD (computational fluid dynamics) software STAR-CCM+ and overlapping mesh technique, and the CFD simulation results are verified with published experimental work. First, the design concept of the hydraulic turbine is presented, focusing on the design of the blades and transmission mechanism to ensure the stability of the structure. Second, the effect of two-dimensional parameters on the flow field characteristics and efficiency is investigated, and then three-dimensional design parameters, such as blade helix angle and hub-to-tip ratio, are considered. The results show that a 20% increase in blade density results in a 10.74% increase in efficiency. Regarding flow velocity, a maximum output of 2.4 kW was achieved for four operating conditions (1.0, 1.5, 2.0, and 2.5 m/s). In addition, the average dynamic torque of the helical-blade turbine was 16.44% higher than that of the straight-blade turbine, indicating superior self-starting capability. It was also found that at an aspect ratio of 1.5–1.75 and a helix angle of 80°, the energy capture efficiency of the helical-blade turbine was 33.7%, which was 45.3% higher than that of the straight-blade turbine. Comparative analysis shows that the vertical-axis helical-blade turbine has favorable hydrodynamic performance, especially under low flow conditions, and the design scheme shows obvious advantages, which makes up for the defects of the traditional vertical-axis straight-blade turbine with poor self-starting ability and low efficiency, and fills up the research gaps of vertical-axis turbine design optimization, which is of certain research value. [ABSTRACT FROM AUTHOR]

Given the typical characteristics of self-propulsion and jack-up wind turbine installation vessels (WTIVs), including their full and blunt hull form and complex appendages, this paper combines the model test method with the RANS-based CFD numerical prediction method to experimentally and numerically study the resistance of the optimized hull at different spudcan retraction positions. The calm water resistance components and their mechanisms of WTIVs based on T-BOW were obtained. Furthermore, using the multivariate nonlinear least squares method, an empirical formula for rapid resistance estimation based on the Holtrop method was derived, and its prediction accuracy and applicability were validated with a full-scale ship case. This study indicates that the primary resistance components of such low-speed vessels are viscous pressure resistance, followed by frictional resistance and wave-making resistance. Notably, the spudcan retraction well area, as a unique appendage of WTIVs, exhibits a significant "moonpool additional resistance" effect. Different spudcan retraction positions affect the total calm water resistance by approximately 20% to 30%. Therefore, in the resistance optimization design of WTIVs, special attention should be paid to the matching design of the spudcan structure and the hull shell plate lines in the spudcan retraction well area. [ABSTRACT FROM AUTHOR]

To address the issues concerning energy conversion efficiency and total energy in the propulsion process of wave energy conversion devices in deep water environments, this study examines the array layout of the existing dual-buoy point-absorption wave energy converter. Two array layouts, namely linear and triangular, are proposed. The coupling hydrodynamic coefficient between the dual-buoy wave energy converter array and the wave action is determined using the linear wave hydrodynamic theory. The optimal PTO damping coefficient of the dual-buoy wave energy converter array can be determined by combining the multi-degree-of-freedom vibration theory and optimization method. In this study, we introduce the array impact factor to conduct a comprehensive investigation into the energy conversion characteristics of dual-buoy wave energy converter arrays with linear and triangular configurations. We examine the effects of various factors such as wave angles, float spacing, and array layout on the wave energy conversion of dual-buoy wave energy converter arrays, as well as the causes of interference. Furthermore, the optimal wave energy capture impact factor of the linear array initially increases and then decreases with the wave direction angle and the distance between the buoys. This suggests that there is an ideal wave angle and spacing arrangement that can enhance the efficiency of the array system. The peak values of the optimal wave energy capture interference factors of the triangular array are all greater than 1, confirming that the array arrangement effectively improves the energy capture efficiency of the device. These research findings provide a theoretical basis for the engineering application of deep-water wave energy utilization and serve as a foundation for optimizing and designing the layout of oscillatory buoy wave energy generation converters. [ABSTRACT FROM AUTHOR]

Objective: To systematically evaluate the impact of physical exercise intervention on children with acute lymphoblastic leukemia (ALL) during the treatment and rehabilitation consolidation periods. Method: Randomized controlled trials (RCTs) were retrieved from PubMed, Scopus, Web of Science, CNKI, and Cochrane databases, with a search time range from database establishment to September 1, 2023. The quality of the included RCTs was evaluated using the Cochrane risk assessment tool, and a systematic evaluation was conducted using RevMan 5.4. The study has been registered with INPLASY (registration number: 202390100). Result: A total of 12 RCTs including 423 subjects was included. The meta-analysis results showed that long-term exercise intervention can effectively improve the endurance performance (SMD = 1.37, 95% CI 0.45 to 2.29, p = 0.004), functional mobility (MD = − 1.17, 95% CI − 1.85 to − 0.49, p = 0.0008), cancer-related fatigue (CRF) (MD = − 1.25, 95% CI − 1.69 to − 0.80, p < 0.00001), and quality of life (QOL) (MD = 4.93, 95% CI 1.80 to 8.05, p = 0.002) of ALL children during the treatment and rehabilitation consolidation periods. Its promoting effect on the muscle strength (SMD = 0.53, 95% CI − 0.33 to 1.39, p = 0.23) and bone mineral density (BMD) (SMD = 0.48, 95% CI 0.20 to 0.77, p = 0.05) of the subjects was not significant. Further meta-analysis showed that exercise intervention with a duration of less than 1 year (SMD = 0.91, 95% CI 0.55 to 1.28, p < 0.00001) rather than more than 1 year (SMD = − 0.16, 95% CI − 0.61 to 0.29, p = 0.49) can effectively reduce subject BMD, while in terms of strength, exercise intervention can effectively improve strength during the treatment period (SMD = 0.97, 95% CI 0.40 to 1.54, p = 0.0008) rather than the consolidation period (SMD = − 0.27, 95% CI − 1.08 to 0.53, p = 0.51). Conclusion: Long-term regular exercise can effectively improve the endurance, functional mobility, CRF, and QOL of children with ALL in the rehabilitation and treatment consolidation stages. Their strength and BMD may be influenced by the timing of treatment and the intervention cycle, respectively. Considering the limited number of included literature and the instability of some outcome indicators, it is necessary to design more comprehensive and rigorous high-quality RCTs in the future to test the exercise efficacy of ALL children. [ABSTRACT FROM AUTHOR]

In order to improve the wave energy capture rate of the buoy of a wave energy generation device, this paper proposes a multi-degree of freedom method to optimize the shape of the buoy with maximum wave energy capture. Firstly, a multi-degree of freedom wave energy converter was designed, and the buoy shape was defined using a B-spline curve to generate the shape vector; then, a numerical model of the multi-degree of freedom wave energy converter was established and numerical calculations were carried out using AQWA/WEC-Sim software; on this basis, the particle swarm optimization algorithm was introduced to find the buoy shape corresponding to the maximum wave energy capture. Finally, the optimization of the buoy shape was in irregular waves. The results show that as the wave energy capture increased, the buoy shape tended to be flatter, with a smaller taper, and the optimal buoy shape had a better motion response than the conventional cone buoy. Eventually, the correctness of the buoy shape optimization method was verified through experimental testing. [ABSTRACT FROM AUTHOR]

The leading group of the State-owned Enterprise Reform of the State Council of China launched a three-year Double Hundred Action for state-owned enterprises in 2018. This study empirically examines the effect of the Double Hundred Action from the perspective of innovation investment using a sample of state-owned listed enterprises from 2013 to 2020. The study finds that the Double Hundred Action significantly improves the innovation investment of state-owned listed enterprises. Furthermore, our main results are more pronounced for firms with competitive industries, a low ratio of independent directors, and auditors not belonging to the 'Big Four'. This study explores the factors influencing corporate innovation from the new perspective of the Double Hundred Action, and also enriches the study of the economic consequences of SOE reforms. This study provides empirical evidence of the positive effects of SOE reforms in emerging markets and has important policy implications for deepening the governance of SOEs. [ABSTRACT FROM AUTHOR]

Studying the dynamic characteristics of the platform under unsteady loads is of great significance to the development of floating offshore wind turbines (FOWTs). In this work, a 15 MW semi-submersible FOWT is extensively simulated using OPENFAST software, and the influence of turbulent wind and irregular waves on the platform's motion is analyzed in detail. Results show that the surge motion of the platform of a complete FOWT system is mainly affected by wind speed, and the influence of turbulence intensity (TI) is slightly greater than the wave height. The heave motion is most significantly affected by the wave height. When the wave height is large, the influence of wind speed on the platform gradually decreases, and the effect of TI becomes more evident. The pitch and yaw motions are greatly affected by the wind speed and TI. The research results can serve as a reference for the platform design of large FOWTs in the future. [ABSTRACT FROM AUTHOR]

Transition metal selenides with high performance were thought to be viable electrode materials for alkali-ion batteries. By combining a simple hydrothermal technique with vacuum selenization treatment to generate FeSe2@3DGF grown on three-dimensional graphene foam backbone, a promising anode material for sodium-ion batteries was designed in this article. FeSe2@3DGF had good electrochemical properties, a large reversible capacity, and cycle stability. In particular, the FeSe2@3DGF electrode can provide a reversible capacity of 600.8 mAh g−1 for sodium-ion batteries after 300 cycles at a current density of 500 mA g−1. [ABSTRACT FROM AUTHOR]

Objective: To understand the mechanism of dual activation of the brain and heart in pistol athletes during shooting performances, through synchronized monitoring of electroencephalogram (EEG) and electrocardiogram (ECG). Methods: Eighteen adolescents air pistol athletes were placed in a simulated competition environment and performed 40 self‐paced shooting tasks, and simultaneously monitored the athletes' EEG, ECG, and shooting performance during the preparation period. Results: (1) In the successful performance, the power values of the alpha wave of the athlete's T7 area showed a significant upward trend 6 s before the shot, but there was no significant change in the alpha wave in the T8 area. In the failure performance, the alpha wave in the T7 and T8 areas did not change significantly 6 s before the shot. (2) The Fz theta wave power value of athletes in successful performance showed a significant upward trend in the 6 s before firing, and in the failure performance, it showed an "inverted U‐shaped" characteristic of rising first and then decreasing. (3) Regardless of whether it was a success or a failure, the SMR wave power value of the athlete's central area has no significant change before the shot. (4) At 6 s before the shot, the athlete's heart rate and R‐R interval (RRI) in the successful performance showed a significant decline and rise, respectively, but there was no significant change in the failure performance. (5) Approaching the firing time, the athletes' EEG and ECG have a more significant correlation in successful performance and a more synchronized trend, while the correlation was lower in failure performance. Conclusions: The psychophysiological state of young air pistol athletes was closely related to shooting performance. If the brain–cardiac system maintains a benign dual activation level during the aiming and firing period, it will be beneficial to the improvement of shooting performance, otherwise, it was easy to reduce shooting performance. [ABSTRACT FROM AUTHOR]

Cerebral vascular accident (CVA) is one of the main causes of chronic disability, and it affects the function of daily life, so it is increasingly important to actively rehabilitate patients' physical functions. The research confirmed that the nutrition supplement strategy is helpful to improve the effect of sports rehabilitation adaptation and sports performance. The patients with chronic strokes (whose strokes occur for more than 6 months) have special nutritional needs while actively carrying out rehabilitation exercises, but there are still few studies to discuss at present. Therefore, this paper will take exercise rehabilitation to promote muscle strength and improve muscle protein synthesis as the main axis and, through integrating existing scientific evidence, discuss the special needs of chronic stroke patients in rehabilitation exercise intervention and nutrition supplement one by one. At the same time, we further evaluated the physiological mechanism of nutrition intervention to promote training adaptation and compared the effects of various nutrition supplement strategies on stroke rehabilitation. Literature review pointed out that immediately supplementing protein nutrition (such as whey protein or soybean protein) after resistance exercise or endurance exercise can promote the efficiency of muscle protein synthesis and produce additive benefits, thereby improving the quality of muscle tissue. Recent animal research results show that probiotics can prevent the risk factors of neural function degradation and promote the benefits of sports rehabilitation. At the same time, natural polyphenols (such as catechin or resveratrol) or vitamins can also reduce the oxidative stress injury caused by animal stroke and promote the proliferation of neural tissue. In view of the fact that animal research results still make up the majority of issues related to the role of nutrition supplements in promoting nerve repair and protection, and the true benefits still need to be confirmed by subsequent human studies. This paper suggests that the future research direction should be the supplement of natural antioxidants, probiotics, compound nutritional supplements, and integrated human clinical research. [ABSTRACT FROM AUTHOR]

Free vibration analyses of lattice sandwich beams with general elastic supports have rarely been discussed in this field's literature. In this paper, a unified method is proposed to study the free vibration characteristics of lattice sandwich beams under various boundary conditions. The proposed method is to convert the three truss cores of lattice sandwich beams into an equivalent homogeneous layer and introduce two different types of constraint springs to simulate the general elastic support boundary at both ends of lattice sandwich beams. By changing the rigidity of the boundary restraint spring, various boundary conditions can be easily obtained without modifying the solving algorithm and solving process. In order to overcome all the discontinuities or jumps associated with the elastic boundary support conditions, the displacement function of lattice sandwich beams is usually obtained as an improved Fourier cosine series along with four sine terms. On this basis, the unknown series coefficients of the displacement function are treated as the generalized coordinates and solved using the Rayleigh–Ritz method. The correctness of the present method is verified through comparison with existing literature. The calculation results of the present method are highly accurate, indicating that the present method is suitable for analyzing the vibration characteristics of lattice sandwich beams with general elastic supports. In addition, the effects of beam length, panel thickness, core height, radius and truss inclination on the natural frequencies of lattice sandwich beams with arbitrary boundary conditions have been discussed in this paper. [ABSTRACT FROM AUTHOR]

It is rather challenging to collect ocean wave energy at high efficiency because of its ultra-low frequencies and variable amplitudes. Triboelectric Nanogenerator (TENG) technology is more suitable for harvesting low-frequency than electromagnetic power generation technology. In this work, we designed a built-in cylindrical Triboelectric Nanogenerator (C-TENG) installed inside the ocean buoy (BUOY-41). The hydrodynamic properties of the C-TENG are consistent with the ocean buoy, which are calculated by CFD software (Star-CCM+). The Energy Capture Properties of the C-TENG are established by the finite element software (COMSOL). The C-TENG has high power density (30 mW/m2) and can meet the power demand of the ocean buoy (10 mW). The implementation of the present work is of great academic value and practical significance for the development of efficient marine renewable energy conversion technology, enhancement of marine equipment energy replenishment, enrichment of hydrodynamic theories and revealing of the complex mechanisms. [ABSTRACT FROM AUTHOR]

The Anti-pitching Generating WEC (AG-WEC) combines the floating articulated platform with the wave energy device. The wave energy device is installed between the hinged platform modules to provide damping to reduce the relative pitch while generating electricity at the same time. A semi-analytical solution of the dynamic characteristics of the AG-WEC is developed by the frequency- and time-domain analysis of the device based on the potential flow theory. Based on Eigenfunction Expansion Matching's potential flow theory, the semi-analytical expressions of wave loads and radiation hydrodynamic coefficients of AG-WEC are derived. By establishing a two-degree-of-freedom vibration system, the analytical solution of frequency-domain dynamic characteristics of the AG-WEC is obtained. Based on the analytical solution of Optimal PTO Damping Coefficient, the analytical optimization of the PTO system is realized, and the mechanism of high-efficiency energy capture of the device is revealed. The time-domain dynamic characteristics of AG-WEC under regular and irregular waves are analyzed by introducing the non-linear Power Take-Off (PTO) system and irregular wave theory with combining the Impose Response Function method. [ABSTRACT FROM AUTHOR]

Flexible inflatable membrane structure has the characteristics of light weight, large span, and small stiffness, and it is very sensitive to wind load. Aiming at the dynamic response of marine evacuation inflatable slides under complex and changeable wind loads at sea, the response law of the inflatable slide under different wind directions, wind speeds, and internal pressure conditions is studied by using fluid–solid coupling theory. The most dangerous conditions of evacuation system installation and the ideal internal pressure of the inflatable slide meeting the stability requirements are deduced. The LS-DYNA module is used to simulate the inflation process of the slide. The evacuation sliding is rationally simplified. By changing the inflatable internal pressure of the slide, the variation law of displacement, deformation, and sliding speed of the slide is obtained, and the optimal inflation internal pressure satisfying the evacuation efficiency requirement is obtained. The results show that the inflow wind direction angle of 30° is the most dangerous condition for slideway installation, and the internal pressure of 4000 Pa is the ideal internal pressure to meet the double standards of stability and evacuation efficiency. The numerical results obtained are valuable for analyzing wind resistance of offshore inflatable membrane structures and their practical design and application in evacuation systems. [ABSTRACT FROM AUTHOR]

Liu, H.; Zheng, X.; Zhang, W.; Chen, H.; Kong, F.; Liu, M., and Shu, G., 2019. Multiple freedom interacted influence on the power conversion for mushroom wave energy converter. In: Hoang, A.T. and Aqeel Ashraf, M. (eds.), Research, Monitoring, and Engineering of Coastal, Port, and Marine Systems. Journal of Coastal Research, Special Issue No. 97, pp. 55–70. Nowadays, the design of wave energy converter (WEC) has become a research hotspot of new energy development and utilization. The motion form of traditional WEC is usually in the single degree of freedom model. In order to efficiently utilize wave energy, a multi-degree-of-freedom interactive wave energy converter, namely Mushroom WEC, is proposed in this paper. The device is mainly composed of a spar hinged to the bottom of the sea for pitch motion and a buoy tied to the spar for heave motion along the direction of the spar, which can absorb the potential energy and kinetic energy of the wave at the same time. In this paper, a mathematical motion model is established according to the motion characteristics of the device, and an analytical method based on linear wave theory is used to solve the wave excitation force and hydrodynamic coefficient. Moreover, by introducing two independent PTO systems and using numerical methods to solve the coupled nonlinear equations of motion, the coupled motion effect and power generation performance of Mushroom WEC spar and buoy were analyzed. The result showed that the power generation efficiency of Mushroom WEC is better than that of the traditional single-degree-of-freedom wave energy converter, and the frequency response range of the device can be improved. The research in this paper is of referential significance to the research of wave energy converter moving with multiple degrees of freedom. [ABSTRACT FROM AUTHOR]

In this study, we investigated the hydrodynamic and energy conversion performance of a double-float wave energy converter (WEC) based on the linear theory of water waves. The generator power take-off (PTO) system is modeled as a combination of a linear viscous damping and a linear spring. Using the frequency domain method, the optimal damping coefficient of the generator PTO system is derived to achieve the optimal conversion efficiency (capture width ratio). Based on the potential flow theory and the higher-order boundary element method (HOBEM), we constructed a three-dimensional model of double-float WEC to study its hydrodynamic performance and response in the time domain. Only the heave motion of the two-body system is considered and a virtual function is introduced to decouple the motions of the floats. The energy conversion character of the double-float WEC is also evaluated. The investigation is carried out over a wide range of incident wave frequency. By analyzing the effects of the incident wave frequency, we derive the PTO's damping coefficient for the double-float WEC's capture width ratio and the relationships between the capture width ratio and the natural frequencies of the lower and upper floats. In addition, it is capable to modify the natural frequencies of the two floats by changing the stiffness coefficients of the PTO and mooring systems. We found that the natural frequencies of the device can directly influence the peak frequency of the capture width, which may provide an important reference for the design of WECs. [ABSTRACT FROM AUTHOR]

Liu, M.; Liu, H.; Chen, H.; Chai, Y., and Wang, L., 2018. Performance analysis for a wave energy harvester of piezoelectric cantilever beam. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 976–984. Coconut Creek (Florida), ISSN 0749-0208. In this paper, we present a convenient and economical wave energy harvester that consists of a large piezoelectric cantilever beam and a floating vertical axisymmetric buoy. A spring-mass-damper system is applied to simulate the heaving motion of a wave energy harvester and semi-analytical solutions based on the eigen-function are used to analysis hydrodynamic characteristics of buoy under potential flow theory. The numerical results show the influences of the different lumped and structural parameters for the energy harvesting efficiency. Theoretical analysis and numerical calculation reveal this kind of the wave energy harvester can provide adequate power for the large cantilever beam structure due to the heaving motion of buoy. [ABSTRACT FROM AUTHOR]

Liu, H.; Ao, J.; Chen, H; Liu, M.; Collu, M., and Liu, J., 2018. Performance analysis of a sea javelin wave energy converter in irregular wave. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 932–940. Coconut Creek (Florida), ISSN 0749-0208. Wave energy, as a kind of eco-friendly energy due to its wide distribution and high energy density, has become a hot research topic at home and abroad and is likely to become a new industry in the future. In this article, we adopt a sea javelin wave energy converter (SJ-WEC) which is a floating vertical axisymmetric buoy. At first, semi-analytical solution of SJ-WEC is studied using eigen-function in frequency domain. Then, wave force and hydrodynamic coefficients of frequency domain can be applied into impulse response function (IRF) method to obtain motion and power of SJ-WEC. In the end, we can select ISSC wave spectrum and JONSWAP wave spectrum to represent the irregular wave to apply into IRF method. It is shown and confirmed that the motion and power which are calculated by IRF method are the same as the frequency domain method's so that the results of irregular waves can be confirmed it accurate. The IRF method is applied to the computation of irregular waves in time domain to simulate the real situation in actual sea conditions which are random and irregular. [ABSTRACT FROM AUTHOR]

Liu, M.; Wang, L.; Liu, H.; Ji, X., and Liu, J., 2018. A fractal model for fluid leak rates through contact rough surfaces under a changing fluid pressure. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 343–349. Coconut Creek (Florida), ISSN 0749-0208. The leakage of fluid always emerges from the contact seal area. This phenomenon could be described by fractal porous media theory, in which the region of contact surfaces could be regarded as a porous medium. And Darcy percolation theory has been introduced to analyze the traditional leakage of the area. This paper constructs a fractal model for fluid leak rates of contact rough surfaces under changing fluid pressures. The variation on the pore number, the porosity, the fractal dimensions and the fluid permeability with the change of the liquid pressure is presented in the form of function relationship. The new model is in better agreement with the experiment results compared with the traditional one. [ABSTRACT FROM AUTHOR]

Wave diffraction of two concentric porous cylinders with varying porosity was studied by using an analytical method based on eigenfunction matching. The fluid domain around the cylinders is divided into three sub-domains and in each sub-domain an eigenfunction expansion of the velocity potential is obtained by satisfying the Laplace equation, the boundary conditions on the free surface and on the sea bed. The unknown coefficients of eigenfunction expansions are determined by boundary conditions on the porous hulls. In the paper, the boundary conditions are based upon the assumption that the flow in the porous medium is governed by Darcy's law. Two porous-effect parameters applied on two porous cylinders are functions of the vertical coordinate instead of the constant. Wave loading on the outer and inner cylinder is presented in the numerical results. [ABSTRACT FROM AUTHOR]

Carrier culture is the combination of suspension culture and adherent culture. Carriers could be used to improve the culture efficiency of large-scale culture of adherent benthic diatom. In order to identify a suitable carrier for mass suspension culture of the benthic diatoms Nitzschia sp. powders of seven macroalgae were used as carriers for diatom attachment including Ulva pertusa, degummed Laminaria japonica, Sargassum muticum, Chaetomorpha valida, Zostera marina, Sargassum fusiforme and Sargassum thunbergii. Diatoms could grow on the surface of the suspended carriers and could effectively utilize the nutrients released by the decomposition of these carriers. Among the seven carriers, Ulva pertusa powder was the most effective for Nitzschia culture when comprehensively considering the nutrition of the harvested diatoms and nutrient utilization of the algae carrier by diatoms. The seaweed powder was dried at 80 °C before used as carrier, this process should meet the sterilization requirements for microalgal culture and is easy to implement in the large-scale cultivation of diatoms. Diatoms cultured with carriers were used to feed juveniles Stichopus japonicus with a wet weight of 5.0 ± 2.0 g, as well as diatoms cultured using conventional methods without carriers, and no significant differences were observed between the two kinds of feed. Compared to sea cucumbers fed with commercial feed, the growth rate of S. japonicus fed with carrier-cultured diatoms was approximately 1.5 times greater, and the activities of non-specific immune enzymes were improved in the coelomic fluid including acidic phosphatase, alkaline phosphatase and superoxide dismutase. Feeding sea cucumber with fresh diatoms could effectively reduce the total nitrogen and total phosphorus in the culture water, improve the water quality, and promote the breeding of sea cucumbers, regardless of whether the carrier culture was adopted. [ABSTRACT FROM AUTHOR]

Thebarge platform has the advantages of low cost, simple structure, and reliable hydrodynamic performance. In order to further improve the hydrodynamics of the barge platform and to reduce its motion response in waves, a zero-pressurized air cushion is incorporated into the platform in this paper. The pressure of the zero-pressurized air cushion is equal to atmospheric pressure and thus does not provide buoyancy to the platform. As compared to the conventional pressurized air cushion, the zero-pressurized one has advantages of less air leakage risk. However, due to the coupling effect on the interface between water and air cushion, the influence of the gas inside the air cushion on the performance of the floating body has become a difficult problem. Based on the boundary element method, the motion response of the zero-pressurized air-cushion-assisted barge platform under regular and irregular waves is calculated and analyzed in the paper. Compared with the barge platform without air cushion, numerical results from the theoretical method show that in regular waves, the air cushion could significantly reduce the amplitude of heave and pitch (roll) response of the round barge platform in the vicinity of resonance. In irregular waves, the air cushion also observably reduces the pitch (roll) motion, though amplifies the heave motion due to the transfer of heave resonance frequency. Thetheoretical study demonstrates that the zero-pressurized air cushion can reduce the seakeeping motion of barge platforms in high sea states, but might also bring negative effects to heave motion in low sea states. One should carefully design the air cushion for barge platforms according to the operating sea states to achieve satisfactory hydrodynamic performance in engineering application. [ABSTRACT FROM AUTHOR]

Chen, H.; Liu, H.; Ge, H.; Kong, F.; Han, Z., and Yu, D., 2020. Mechanics characteristics of chamber and slide system of vertical slide marine emergency evacuation system. In: Yang, Y.; Mi, C.; Zhao, L., and Lam, S. (eds.), Global Topics and New Trends in Coastal Research: Port, Coastal and Ocean Engineering. Journal of Coastal Research, Special Issue No. 103, pp. 311–317. Coconut Creek (Florida), ISSN 0749-0208. In this paper, the evacuation process of the vertical slide Marine emergency evacuation system and the force under different states of the system are analyzed and explored. The overall scheme of Marine emergency evacuation system with vertical slide is established. The movement of escaping personnel falling in the chute system is deeply analyzed. The slide system is divided into a network-man model and a load-bearing steel cable model. On this basis, the steel-flexible body contact model (that is, the "ball-net" collision model) and the single-side fixed series multi-degree-of-freedom vibration model are established. And the mathematical exploration and simulation analysis. In the process of analysis, the falling speed, falling angle and boundary conditions of simulation analysis were determined one by one, and the analysis result was the load output of the top of the load-bearing steel cable. The simulation results are in line with the expected estimation. After optimizing the results of the slide dynamic analysis, the dynamic response of the space steel frame is analyzed as the input condition of the dynamic analysis of the space steel frame, and the results meet the expected requirements. [ABSTRACT FROM AUTHOR]

This paper introduces a new point-absorber wave energy converter (WEC) with a moonpool buoy—the moonpool platform wave energy converter (MPWEC). The MPWEC structure includes a cylinder buoy and a moonpool buoy and a Power Take-off (PTO) system, where the relative movement between the cylindrical buoy and the moonpool buoy is exploited by the PTO system to generate energy. A 1:10 scale model was physically tested to validate the numerical model and further prove the feasibility of the proposed system. The motion responses of and the power absorbed by the MPWEC studied in the wave tank experiments were also numerically analyzed, with a potential approach in the frequency domain, and a computational fluid dynamics (CFD) code in the time domain. The good agreement between the experimental and the numerical results showed that the present numerical model is accurate enough, and therefore considering only the heave degree of freedom is acceptable to estimate the motion responses and power absorption. The study shows that the MPWEC optimum power extractions is realized over a range of wave frequencies between 1.7 and 2.5 rad/s. [ABSTRACT FROM AUTHOR]

In this work the hydrodynamic performance of a novel wave energy converter configuration was analytically and numerically studied by combining a moonpool and a wave energy buoy, called the moonpool platform–wave energy buoy (MP–WEB). A potential flow, semi-analytical approach was adopted to assess the total (incident, diffraction, radiation) wave forces acting on the device, and the wave capture and energy efficiency performance of this configuration was assessed, both in the time and frequency domain. The performance of the two configurations, single float and double float, were analyzed and compared in terms of diffraction force, added mass radiation force, motion, and power in the frequency domain. Using an impulse response function-based (IRF) method, the frequency domain results were converted in the time domain. The same parameters in the time domain were derived and the main results were confirmed. Wave energy conversion efficiency was significantly increased due to the resonance phenomenon inside the moonpool. [ABSTRACT FROM AUTHOR]