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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]

Wave energy and ocean current energy are considered stable, reliable, and highly predictable renewable energy sources. The development of ocean current energy conversion technology is crucial in addressing power shortages. However, the low velocity of most ocean currents worldwide, typically less than 1.5 m/s, poses a challenge for traditional ocean current energy capture devices. Current estimations of power generation from underwater devices often significantly differ from actual results. This study presents an eel-type power generation device designed for underwater use, investigates the design and optimization of a hydraulic power take-off (PTO) system suitable for such devices, and examines key components of the hydraulic PTO system like variable hydraulic motors and generators. Analytical research was conducted to understand its operational characteristics, with a focus on components such as the accumulator, speed control valve, and energy storage flywheel. The article also delves into the hydrodynamic and energy conversion characteristics of the device under shallow water wave and current conditions, enhancing the hydraulic PTO system model and establishing an integrated calculation model for real-time data transmission during the calculation process. Through evaluations of pitch angle and power generation under varying sea conditions, the study explores the impact of hydraulic motor displacement and damping coefficient on the hydrodynamic and power generation characteristics of the device, further validated through sea trials. The study findings indicate a high level of parameter adaptation among the components of the hydraulic system. The addition of an accumulator to the system results in smoother output response curves, suggesting that the accumulator absorbs impacts and stabilizes the hydraulic power transmission system. The proposed comprehensive calculation method enables a more precise prediction of the performance of the eel power generation device in real marine environments, capturing its movement behavior and power generation characteristics. Adjusting the motor displacement or damping coefficient under specific conditions can optimize the total damping of the hydraulic PTO system for maximum power output. The optimal power point of the hydraulic power generation system varies for different sea conditions, with a potential power generation efficiency of up to 80.3% under certain circumstances. • An eel power generation device suitable for deep-sea micro-current sea condition and wave-current combined sea condition • Design and optimal Control of power take-off (PTO) system • The integrated calculation of hydrodynamic and energy conversion is studied. • Comparison of the results of sea test and integrated calculation. [ABSTRACT FROM AUTHOR]

Liver fibrosis (LF) is a common reversible consequence of chronic liver damage with limited therapeutic options. Yinchen Gongying decoction (YGD) composed of two homologous plants: (Artemisia capillaris Thunb , Taraxacum monochlamydeum Hand.-Mazz.), has a traditionally application as a medicinal diet for acute icteric hepatitis. However, its impact on LF and underlying mechanisms remain unclear. This study aims to assess the impact of YGD on a carbon tetrachloride (CCl 4) induced liver fibrosis and elucidate its possible mechanisms. The study seeks to establish an experimental foundation for YGD as a candidate drug for hepatic fibrosis. LC-MS/MS identified 11 blood-entry components in YGD, and network pharmacology predicted their involvement in the FoxO signaling pathway, insulin resistance, and PI3K-AKT signaling pathway. Using a CCl 4 -induced LF mouse model, YGD's protective effects were evaluated in comparison to a positive control and a normal group. The underlying mechanisms were explored through the assessments of hepatic stellate cells (HSCs) activation, fibrotic signaling, and inflammation. YGD treatment significantly improved liver function, enhanced liver morphology, and reduced liver collagen deposition in CCl 4 -induced LF mice. Mechanistically, YGD inhibited HSC activation, elevated MMPs/TIMP1 ratios, suppressed the FoxO1/TGF-β1/Smad2/3 and YAP pathways, and exhibited anti-inflammatory and antioxidant effects. Notably, YGD improved the insulin signaling pathway. YGD mitigates LF in mice by modulating fibrotic and inflammatory pathways, enhancing antioxidant responses, and specifically inhibiting FoxO1/TGF-β1/Smad2/3 and YAP signal pathways. [Display omitted] [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, 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]

Abstract Multiple concentric perforated cylindrical walls are newly suggested for the protection of both the internal cylinder and themselves. The porosity parameter is introduced to measure the ability of the perforated wall in dissipating the energy when the fluid passes through it. The 3-dimension linear potential theory based upon the eigenfunction matching method considering the nonlinear boundary conditions is used for the hydrodynamic analysis of the structures. The wave forces on the inner cylinder and protective walls are calculated considering various porosity parameters and radius ratios. The wave elevations at the free surface in the fluid domain for a considered parameter proportion and radius ratio with various numbers of porous walls are further examined. The numerical results are vividly depicted and show that the wave loads on the inner cylinder can be highly reduced by setting one or more porous walls externally. When there is only one perforated wall, whether it is fully or partially perforated at the upper part has little influence in reducing the wave loads on the inner cylinder. In this case, the frequencies where the wave excitation forces approach zero on the outer wall and approach maximum on the inner cylinder are explained by introducing the sloshing problem and further confirmed by the analytical formulas. More numbers of protective walls can better balance the wave elevations and excitation forces on themselves by adjusting the porosity parameter proportions and radius ratios of them. Highlights • Multiple concentric perforated walls are newly suggested for the protection of both the internal cylinder and themselves. • The frequencies where the wave forces approach zero on the outer wall and maximum on the inner cylinder are explained. • The wave elevations for a considered parameter proportion and radius ratio with various numbers are further examined. • More numbers of protective walls can better balance the wave elevations and excitation forces on themselves. [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]

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]

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]

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]

A fast simulation method of wind turbine wake field based on the combination of lifting line and annular vortex elements is proposed to simulate the bound circulation on the blade by means of lifting line, and to simulate the evolution of the wake field by releasing the annular vortex elements through the blade. The method can be iterated until convergence is sufficient by distributing the vortex elements basin-wide through periodicity in the initialization stage. The accuracy and applicability conditions of the method are verified by comparing the above method with wind tunnel tests and software simulation results using different methods. The method is clear and simple, with low computational cost and high computational accuracy. [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]

Ocean current energy is a stable, reliable, and highly predictable renewable energy source. The effective development of ocean current energy conversion technology is beneficial in addressing the issue of power shortage. However, the majority of current velocities worldwide are below 1.5 m/s, limiting the feasibility of using conventional current energy capture devices. This paper presents a vortex induced vibration based deep sea microfluidic eel energy capture device (VIV-EEL) designed to efficiently harness energy in low-speed current environments. The system employs Computational Fluid Dynamics (CFD) to develop a series of computational models that couple underwater multibody fluid-solid interactions. These models are subsequently validated through experiments. The study analyzed the flow field of VIV-EEL under different working conditions and discussed the impact of several dimensional parameters of the elastically supported cylinders, structural parameters of raft plates, and flow velocity on the hydrodynamic performance. The results demonstrate that the energy capture efficiency of VIV-EEL is enhanced by the vorticity vibration effect. It is evident that there exists an optimal radius size for the elastic support column to achieve the most favorable resonance effect in the flow field of VIV-EEL. The energy capture characteristics of the raft plate show a linear relationship with its structural parameters, enabling quantitative design according to the requirements of the power take-off system (PTO). Moreover, VIV-EEL exhibits a lower start-up flow velocity compared to traditional current energy capture devices, enabling it to initiate and capture energy at a flow rate of 0.3 m/s. This innovative solution offers technical support for efficient low-speed current energy capture. [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]

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]

The concept of installing two wind turbines on a floating platform, known as a floating twin-rotor wind turbine system, has recently garnered significant interest. This configuration can harness greater wind energy resources, reduce installation and mooring costs by sharing mooring lines, and minimize losses due to wake effects between turbines through yaw control. However, previous research has not sufficiently addressed the dynamic performance analysis of such systems. This study focuses on a high-capacity floating twin-rotor wind turbine system and develops an aero-hydrodynamic coupled analysis method based on the free vortex wake method and potential flow theory, specifically tailored for the twin-rotor configuration. This method facilitates real-time iterative calculations of wind and wave loads acting on the system and suggests optimization strategies for its design. Our findings indicate that the design of high-capacity floating twin-rotor systems can significantly reduce costs. Furthermore, the twin-rotor floating system design enhances wake recovery and achieves optimal comprehensive performance when the rotor spacing ratio (S/D) is 1.2 for the IEA 15 MW turbine. The coupled interactions induce periodic variations in aerodynamic performance, with the amplitude of these variations increasing with turbulence intensity. This research lays a theoretical foundation for advancing the design, platform optimization, and coupled computational analyses of large-capacity, large-scale floating twin-rotor wind turbine systems. • Floating twin-rotor wind turbine system. • Simulation method combine free vortex wake and potential flow theory. • Wake analysis of twin-rotor under turbulence effect. • System aero-hydro coupled motion analysis under turbulence effect. • The rotor spacing ratio in this system is recommended to be 1.2 under consideration of wake recovery and cost. [ABSTRACT FROM AUTHOR]

An oscillating hydrofoil-wave energy conversion device was developed to address the challenge of self-supply for ocean vehicles by harnessing wave energy for electricity generation. This study focuses on the numerical simulation of the device’s hydrodynamic characteristics and energy capture performance. The paper begins by establishing a hydrodynamic numerical analysis model using CFD technology for the multi-body hinged system. The hydrodynamic characteristics of this system are examined under various wave conditions. Subsequently, an energy conversion model for the multi-body hinged system, considering a nonlinear power take-off (PTO) system, is established through an equivalent damping simulation method. This model is used to investigate the power generation performance and energy conversion efficiency of the cylindrically oscillating hydrofoil multi-body hinged system under different damping coefficients and wave conditions. The research findings indicate that the motion characteristics and wave energy capture efficiency of the hydrofoil are significantly influenced by the wave height, period, and damping coefficient of the PTO system. In addition, there are differences in energy harvesting effect between front and rear oscillating hydrofoils. The maximum power generation efficiency achieved by the oscillating hydrofoil-wave energy conversion device reaches 21.68%, with an anticipated peak power output of 1.84 kW under real sea conditions. [ABSTRACT FROM AUTHOR]

An accurate solution method for analyzing free vibration of multi-span lattice sandwich beams under arbitrary boundary conditions is proposed in this investigation. Unlike in most existing studies where solutions are often developed for a particular type of boundary conditions. In this paper, at boundaries and supports, the linear displacement springs and rotational springs are introduced to simulate the boundary and support forces of multi-span lattice beams, and by adjusting these elastic stiffness values, the arbitrary boundary conditions can be simulated furthermore. All the displacement field functions of multi-span lattice beams are uniformly expanded into an improved Fourier cosine series supplemented with four sine series, which are introduced to eliminate the discontinuity or jump at the boundaries and supports during the solution process. The unified vibration equation of multi-span lattice sandwich beams under arbitrary boundary conditions is constructed based on the energy method. The Rayleigh–Ritz method is used to solve the free vibration characteristics of multi-span lattice sandwich beams. Based on the current method, the free vibration characteristics of multi-span lattice sandwich beams under arbitrary number of spans, arbitrary boundaries and supports can be studied without modifying the solution algorithm and program. The correctness as well as the accuracy of the current method are verified through comparison with those obtained from other analytical approach. Numerical results are presented to show that the current method is very suitable for analyzing the free vibration of multi-span lattice beams under arbitrary boundary conditions. In addition to this, the geometric parameters, as well as the elastic modulus and damping of materials, are analyzed for their effect on the vibration characteristics of multi-span lattice sandwich beams under different boundary conditions. • In this study, an accurate solution method for predicting the vibration characteristics of the multi-span lattice sandwich beam under arbitrary boundary conditions has been proposed. • The proposed method is suitable for analyzing the free vibration of multi-span lattice beams under arbitrary boundary conditions, and only stiffness of the restraining spring needs to be changed. • Parameter study of the multi-span lattice beam under arbitrary boundary conditions is presented. [ABSTRACT FROM AUTHOR]

Anti-pitching Generating Wave Energy Converter (AGWEC) uses the relative pitch motion between floating bodies to push the hydraulic energy storage PTO movement, which reduces the relative pitch between floating bodies while generating power. In this paper, based on the CFD method and the potential flow theory with viscosity modification, the motion characteristics of AGWEC in waves are studied. The viscous dissipation term is introduced into the boundary condition of potential flow, and the viscous modified potential flow theory method is established. The Eigenfunction Expansion Matching (EEM) method and Impulse Response Function (IRF) method are used to analyze the motion response of the device in frequency domain and time domain respectively. At the same time, compared with the results of CFD method based on Star-CCM+, the universality of the two methods is proved, and the motion characteristics of the AGWEC based on (non)linear PTO system and the variation law with the relevant parameters are obtained under different floating body axial spacing and wave frequency. • The viscous dissipation term is introduced and the viscosity disspation term of Anti-pitching Generating WEC is obtained. • Combined with CFD method, the new method is verified, and the viscosity dissipation correction coefficient is obtained. • The motion characteristics of AGWEC based on (non)linear PTO system in real fluid are studied. [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]

The Combined Axisymmetric Buoy (CAB), a vertical axisymmetric buoy, has the potential to deliver a high energy absorption power. Considering the CAB-Wave Energy Converters (WEC), in order to achieve higher efficiency, the Power Take Off (PTO) systems, which converts the float motion into energy output, needs to be properly controlled. In this paper, a PTO control method for a CAB-WEC under irregular wave conditions is proposed. Based on the semi-analytical solution obtained in the time domain, a numerical optimization is carried out. The optimal PTO damping coefficients under different wave conditions are obtained, by considering the parameter defined as "capture width ratio". The expression of the optimal PTO damping coefficient in the frequency domain is derived by an analytical method. Based on the semi-analytical solution of time domain dynamic characteristics and analytical method, a comparison between frequency domain optimization and time domain optimization is presented. In general, the two approaches arrive to very similar conclusions, even if with the time domain methodology a slightly higher capture width ratio is achieved. The experimental results have been used to validate the time domain optimization method and the variation in optimal average capture width ratio results. • A PTO control method for a CAB-WEC under irregular wave conditions is proposed. • The relationship between frequency domain optimization and time domain optimization is obtained. • The optimum time domain PTO damping coefficient of irregular waves are discussed and verified by experiments. [ABSTRACT FROM AUTHOR]

In this paper, a hybrid Oscillating Water Column (OWC)system combining with a heaving floater Wave Energy Converters (WEC) was investigated. The traditional cylindrical-type breakwater consists of dual cylinders with an opening inlet located at the outer wavefront wall, allowing a ring-type wave chamber formed between two cylinders. The oscillating buoy OB is hinged at the front of the OWC device. The WAVE Chamber formed between the two breakwater cylinders is to be used as OWC. Based on the Computational Fluid Dynamics (CFD) software Star CCM+, A three-dimensional numerical wave tank is developed to investigate the hydrodynamic performance of the hybrid system, and the numerical model is validated with published experimental results. The power take-off (PTO) damping performance and the hydrodynamic efficiency affected by water conditions and geometrical dimensions of the device are discussed. Results show that the after combining the floater to the breakwater-type WEC, a great improvement on frequency bandwidth was achieved and the efficiency increase to 83.28% compared to the case of a single device, which was of 57%. Furthermore, the effects of the opening inlet height and the volume ratio of the OWC chamber were studied to optimize the certain geometrical parameters. Lower height ratio of the opening inlet of the OWC chamber should be avoid for larger water depth condition while designing such a hybrid system. • An OWC-type breakwater with a heaving floater is put forward. • The new hybrid system has good improvement on power extraction performance. • The dual-cylindrical OWC can more effectively extract shorter waves and protect coast. • Effect of geometrical properties and PTO damping on hydrodynamic efficiency are shown. • Cost-sharing of integrated system can make WEC device economically competitive. [ABSTRACT FROM AUTHOR]

As a continuation of authors' previous work, this work extends and hackles the numerical method for wind turbine wakes based on the vortex method, and proposes the Lagrangian actuator model (LAM) which is used for the representation of the wind turbine rotor under the Lagarangian framework. This paper provides two examples of the LAM, the Lagrangian actuator line (LAL) model and the Lagrangian actuator disc (LAD) model, and constructs matching numerical methods for wake predictions respectively. Those methods have high computation efficiency, and the results coincide with the wind tunnel test data well. Moreover, based on that, a vorticity description framework centered on vortex geometric structures is established to illustrate wind turbine wake phenomena and explore the wake evolution mechanism. • A new wake prediction method based on the vortex method is developed. • The Lagrangian form of the actuator model is presented to handle the boundary condition. • A vorticity description framework is established to explore the wake evolution mechanism. [ABSTRACT FROM AUTHOR]

A Mathematical model for total mass flow rate per unit area and total permeability of real gas flow in fractal porous media was proposed on the basis of fractal theory. Proposed models in this paper paid attention to the influence of real gas effect on gas, taking transition regime as the coupling of slip regime and Knudsen diffusion, considering multi-flow-regime coexist, multi-flow-regime is continuum flow regime, slip flow regime, transition flow regime and Knudsen diffusion regime., pore which pore diameter is λ mass flow rate per unit area multiply corresponding pore number d N obtain mass flow rate(d q). Integrate d q within corresponding diameter range and divide fractal porous media work out corresponding flow regime the mass flow rate per unit area. The total mass flow rate per unit area was then calculated through integrating over the mass flow rate deduced, where different flow regimes have been engaged, including continuum regime, slip regime, transition regime and Knudsen diffusion. Based on the Darcy theory, the total permeability was then calculated. In order to verify correctness of model, compare proposed model to Wang's model and Fan's model. Calculate correlation coefficient of proposed model and Wang's model, R 2 = 0.9912 ; Calculate correlation coefficient of proposed model and Wang's model, R 2 = 0.9997. Indicate that proposed model can fit well with Wang's model and Fan's model, proposed model can correctly predict total permeability. And calculate correlation coefficient of D.B.Bennion experiment data and three model. In the last part, the paper analyzed the influence factor of total mass flow rate per unit area and total permeabilities and mass flow rate per unit area and permeability of different flow regimes. The concludes as follow: (1) total mass flow rate per unit area, total permeability and each flow regime mass flow rate per unit area and permeability increase with fractal dimension(D p) increasing and tortuous fractal dimension(D t) decreasing. Variation of D p and D t has different influence on each flow regime. D p and D t has most influence on Knudsen diffusion flow regime, least influence on continuum flow regime. (2) Real gas effect affects the mass flow rate per unit area and permeability in different flow regime by affecting the mean free path of gas molecule. Whether consider real gas effect would cause great difference, maximum difference is 232.35%. (3) Flow regime that have the lowest Knudsen number play leading role in variation of total mass flow rate and total permeability. (4) The more maximum pore diameter of fractal porous media, the more significant influence of total mass flow rate per unit area and total permeability. Maximum pore diameter has different influence on each flow regime, has most influence on Knudsen diffusion flow regime, least influence on continuum flow regime. • Taking transition regime as the coupling of slip regime and Knudsen diffusion. • Consider the effect of real gas effects on gas flow in fractal porous. • A unified models of gas flow in fractal porous mass flow rates and permeabilities are obtained. • Analysis the effect of different factor on the mass flow rates and permeabilities of different flow regimes. [ABSTRACT FROM AUTHOR]

The industrial process involving gas liquid flows is one of the most frequently encountered phenomena in the energy sectors. However, traditional methods are practically unable to reliably identify flow patterns if additional independent variables/parameters are to be considered rather than gas and liquid superficial velocities. In this paper, we reported an approach to predict flow pattern along upward inclined pipes (0–90°) via deep learning neural networks, using accessible parameters as inputs, namely, superficial velocities of individual phase and inclination angles. The developed approach is equipped with deep learning neural network for flow pattern identification by experimental datasets that were reported in the literature. The predictive model was further validated by comparing its performance with well-established flow regime forecasting methods based on conventional flow regime maps. Besides, the intensity of key features in flow pattern prediction was identified by the deep learning algorithm, which is difficult to be captured by commonly used correlation approaches. • An integrated method was developed to predict flow regimes via deep learning. • The deep learning predictive model was validated by unified models. • The model has high accuracy in predicting flow patterns of inclined flows. • Impacts of different variables on flow patterns was evaluated quantitatively. [ABSTRACT FROM AUTHOR]

In this paper, a submarine pipeline stopper used in deepwater environment is proposed, and the force, deformation and sealing performance of the rubber barrel in each sealing stage are studied. Based on the Lame equation and the equilibrium equation of the rubber barrel, the mechanics model of the rubber barrel is established. Variation of distribution of the force, axial displacement, radial displacement as well as the stress of the five different hardnesses of rubber barrels during free deformation and contact deformation are analyzed. Compression deformation experiments of five kinds of rubber barrels' hardness are designed based on theoretical analysis, and the theories are verified by the experimental data. The simulation results verify the correctness of the theoretical derivation. The results in this paper provide a basis for the selection of power and stroke for stopper in the submarine pipeline, and provide a reference for the study on impermeability and sealing performance. • The relationship between hardness and deformation of seal rubber for a submarine pipeline stopper is studied. • The hardness and pressure of the rubber seal are changed in the experiment. • The mechanics model of the rubber barrel is established based on the Lame equation and the equilibrium equation of the rubber barrel. • The finite element analysis of mechanical model of the seal rubber for subsea pipeline stopper based on the Lame equation is carried out. • The deformation of the seal is calculated when the sealing condition is satisfied, and verified by experiments. [ABSTRACT FROM AUTHOR]