A new hybrid method of frequency domain and time domain is developed in this paper to predict the motion responses of a flexibly joint multi-body floating system to irregular waves. The main idea of the method is that...A new hybrid method of frequency domain and time domain is developed in this paper to predict the motion responses of a flexibly joint multi-body floating system to irregular waves. The main idea of the method is that the three-dimensional frequency method is used to obtain the hydrodynamic coefficients and the response equations are solved in time domain step by step. All the forces can be obtained at the same time. The motions and nonlinear mooring forces of a box type six-body floating system are predicted. A comparison of the theoretical method-based Solutions with experimental results has shown good agreement.展开更多
Numerical simulation and experimental tests were carried out to examine the hydrodynamic behaviors of a double-column floating system of gravity cage under wave conditions. A floating system of gravity cage can be tre...Numerical simulation and experimental tests were carried out to examine the hydrodynamic behaviors of a double-column floating system of gravity cage under wave conditions. A floating system of gravity cage can be treated as a small-sized floating structure when compared with the wavelengths. The main problem in calculating the wave loads on the small-sized floating structure is to obtain the reasonable force coefficients, which may differ from a submerged structure. In this paper, the floating system of gravity cage is simplified to a 2D problem, where the floating system is set symmetrically under wave conditions. The motion equations were deduced under wave conditions and a specific method was proposed to resolve the problem of wave forces acting on a small-sized floating system of gravity cage at water surface. Results of the numerical method were compared with those from model tests and the hydrodynamic coefficients Cn and Cr were studied. It is found that Cn ranges from 0.6 to 1.0 while Cr is between 0.4 and 0.6 in this study. The results are useful for research on the hydrodynamic behavior of the deep-water gravity sea cages.展开更多
Polyester mooring has become increasing popular to serve as permanent station-keeping system for deepwater floating system during recent years. Comparing to the traditional steel wire mooring,polyester mooring provide...Polyester mooring has become increasing popular to serve as permanent station-keeping system for deepwater floating system during recent years. Comparing to the traditional steel wire mooring,polyester mooring provides significant benefits in deepwater,such as reduced installed capital expenditure (CAPEX) and smaller vertical loads on host platform. Polyester rope is a visco-elastic material,and its stiffness is nonlinear and affected by mean load,load range,loading period and loading history. There is a perception that the polyester stiffness model has significant impact on the floating system's performance. This paper presents a detailed description and comparison of two stiffness models and three analytic approaches,and provides a systematic study of the impact of polyester mooring stiffness modeling on the deepwater floating system performance.展开更多
Floating photovoltaic(FPV)technology is emerging as a highly promising approach to accelerate decarbonization of the global economy,due to its higher power generation efficiency and lower land occupation.With the rapi...Floating photovoltaic(FPV)technology is emerging as a highly promising approach to accelerate decarbonization of the global economy,due to its higher power generation efficiency and lower land occupation.With the rapid development of FPV technology,the mechanical performance degradation of key components caused by the harsh marine environment has become a pressing issue,as it significantly contributes to failure behavior observed in FPV systems.A comprehensive compilation of the mechanical performance of key components in FPV systems is also currently unavailable.Here,the mechanical behavior of each structural component in FPV systems under harsh marine environments is systematically reviewed.It further emphasizes the synergistic effects of mechanical performance degradation among different components on the overall system.The drop-off rate(v)of normalized elongation at break(EAB)of polymer under the synergistic effect of various environmental factors increases from 7.5×10^(−4)h^(−1)to 21.8×10^(−4)h^(−1)compared with the single environmental stress.Moreover,the development of novel materials and innovative mechanical structures applied in FPV systems to enhance mechanical performance is discussed.The novel flexible PV modules applied in FPV systems minimize the loads acting on the mooring lines by 80%and increase power generation by 5%.Notably,this paper provides a theoretical foundation for developing standards of FPV systems,especially the establishment of standards related to the synergistic effects of the mechanical performance degradation of different key components on FPV systems.展开更多
Floating photovoltaic(FPV)systems provide dual benefits in renewable energy generation and water resource utilization,supporting global decarbonization efforts.This study conducts a full life cycle assessment(LCA)of F...Floating photovoltaic(FPV)systems provide dual benefits in renewable energy generation and water resource utilization,supporting global decarbonization efforts.This study conducts a full life cycle assessment(LCA)of FPV systems,covering material production,construction,operation,and decommissioning stages.Particular attention was given to ecological risks,an often overlooked aspect in previous environmental evaluations.A structured ecological risk matrix is developed integrating physical,chemical,and biological indicators to evaluate environmental disturbances caused by FPV systems.The framework was applied to eight representative water bodies in China,including Taihu Lake(characterized by high nutrient loading),Danjiangkou Reservoir(a major drinking water source),and Poyang Lake(an ecologically sensitive wetland).Each site is evaluted using a semi-quantitative scoring system based on ecological sensitivity and FPV disturbance potential.Risk levels were classified to guide deployment suitability(0-6),identify high-risk areas,and support mitigation strategies.The findings revealed significant spatial heterogeneity in ecosystem vulnerability and highlighted the lack of standardized protocols for ecological risk assessment in FPV projects.In response,this study proposed context-specific design recommendations,including adjustments to module density,transparency,and anchoring methods,to minimize ecological impacts.This research provides a transferable tool for incorporating ecological metrics into FPV planning and regulatory review,particularly in freshwater ecosystems.It contributes to the development of risk-informed deployment guidelines and emphasizes the need for long-term ecological monitoring in FPV expansion.展开更多
[Objective] The aim was to investigate different effects of two pH-regulating acids on the root morphology and other physiological growth of Lactuca sativa L.in floating plug transplant system.[Method] HNO3 and H2SO4 ...[Objective] The aim was to investigate different effects of two pH-regulating acids on the root morphology and other physiological growth of Lactuca sativa L.in floating plug transplant system.[Method] HNO3 and H2SO4 were used to adjust pH condition of various nutrient concentrations in lettuce floating transplant system,the effect of two acid treatments on root traits of lettuce were investigated.[Result] These two acids made different effects on root system under a series of nutrient gradients.Under HNO3 treatment,the fresh weight of shoot and root were increased with growth of nutrient concentration;root preformed best when EC was 1.0 μs/cm.Under H2SO4 treatment,when EC was 0.8 μs/cm,the total root length and root surface area,projected area,root volume of lettuce were 344.8 cm,40.9 cm2,13.0 cm2,0.4 m3,respectively,which were significantly higher than those in HNO3 treatment.Compared the influences of acid treatments under same nutrient concentration,the result showed that H2SO4 treatment increased root/shoot ratio and all other root morphological characteristics;however,HNO3 treatment promoted the growth of shoot and lateral root,increased transplanting efficiency and facilitated realizing high yield after transplanted into open-field.[Conclusion] This study will provide theoretical reference for improving plug transplant technology of lettuce.展开更多
The ecological floating bed system is a natural alternative to technical methods of wastewater treatment and involves complex processes induced by plants or microorganisms in the wastewater. This study aimed to identi...The ecological floating bed system is a natural alternative to technical methods of wastewater treatment and involves complex processes induced by plants or microorganisms in the wastewater. This study aimed to identify nutrient concentration variations during Oenanthe javanica （Blume） DC growth and decay in the ecological floating bed system. Results showed that the third-order polynomial equation was suitable to describe pollutant concentration changes, showing that the effect of O. javanica ecological floating bed system on polluted water could be divided into the purification phase and decay phase. During the purification phase, nutrient concentrations rapidly decreased because O. javanica influenced water microbial communities and water physical parameters （i.e., dissolved oxygen, pH, and temperature）, and had a direct uptake of nutrients. However, during the decay phase, nitrogen and phosphorus concentrations in the plant tissues decreased, and these lost nutrients ultimately transferred to water and led to water quality deterioration. Results also showed that the uptake and storage of O. javanica in nutrients were temporary and the plant served only as media of the nutrients removed from the water. Under these circumstances, harvesting was an appropriate intervention to improve the treatment efficiency of O. javanica ecological floating bed system.展开更多
As a promising renewable energy,offshore wind energy currently is gaining more attention,by which the economic and efficient operation of floating wind turbine systems is a potential research direction.This study is p...As a promising renewable energy,offshore wind energy currently is gaining more attention,by which the economic and efficient operation of floating wind turbine systems is a potential research direction.This study is primarily devoted to the analysis of dynamic response of the NREL-5 MW reference wind turbine supported by an OC3-Hywind SPAR-type platform using a recompiled code which combines FAST with WAMIT.To verify the reliability of the recompiled code,the free decay motions of a floating wind turbine system in still water are examined with satisfactory results.After that,thirteen scenarios with different angles between wind and wave from 0°to 90°are investigated.The dynamic responses of the turbine system in various degrees of freedom(DOFs)for different incident wind/wave directions are presented in both time and frequency domains via the fast Fourier transform.展开更多
The development of offshore wind farms was originally carried out in shallow water areas with fixed （seabed mounted） structures. However, countries with limited shallow water areas require innovative floating platfo...The development of offshore wind farms was originally carried out in shallow water areas with fixed （seabed mounted） structures. However, countries with limited shallow water areas require innovative floating platforms to deploy wind turbines offshore in order to harness wind energy to generate electricity in deep seas. The performances of motion and mooring system dynamics are vital to designing a cost effective and durable floating platform. This paper describes a numerical model to simulate dynamic behavior of a new semi-submersible type floating offshore wind turbine （FOWT） system. The wind turbine was modeled as a wind block with a certain thrust coefficient, and the hydrodynamics and mooting system dynamics of the platform were calculated by SESAM soRware. The effect of change in environmental conditions on the dynamic response of the system under wave and wind loading was examined. The results indicate that the semi-submersible concept has excellent performance and SESAM could be an effective tool for floating wind turbine design and analysis.展开更多
In this paper, the impact analysis of air gap concerning the parameters of mooring system for the semi-submersible platform is conducted. It is challenging to simulate the wave, current and wind loads of a platform ba...In this paper, the impact analysis of air gap concerning the parameters of mooring system for the semi-submersible platform is conducted. It is challenging to simulate the wave, current and wind loads of a platform based on a model test simultaneously. Furthermore, the dynamic equivalence between the truncated and full-depth mooring system is still a tuff work. However, the wind and current loads can be tested accurately in wind tunnel model. Furthermore, the wave can be simulated accurately in wave tank test. The full-scale mooring system and the all environment loads can be simulated accurately by using the numerical model based on the model tests simultaneously. In this paper, the air gap response of a floating platform is calculated based on the results of tunnel test and wave tank. Meanwhile, full-scale mooring system, the wind, wave and current load can be considered simultaneously. In addition, a numerical model of the platform is tuned and validated by ANSYS AQWA according to the model test results. With the support of the tuned numerical model, seventeen simulation cases about the presented platform are considered to study the wave, wind, and current loads simultaneously. Then, the impact analysis studies of air gap motion regarding the length, elasticity, and type of the mooring line are performed in the time domain under the beam wave, head wave, and oblique wave conditions.展开更多
Common effect of wave and slip of internal heavy load will make rolling of the roll-on ship serious. This is one of the important reasons for overturn of ro-ro ships. The multibodies System with a floating base is com...Common effect of wave and slip of internal heavy load will make rolling of the roll-on ship serious. This is one of the important reasons for overturn of ro-ro ships. The multibodies System with a floating base is composed of ro-ro ship and slipping heavy load. This paper takes the rolling angle of the ship and the transverse displacement of the heavy load on desk as two freedoms. Making use of analysis of apparent gravitation and apparent buoyancy, the wave rolling moment is derived. By use of dynamic method of multibodies system with a floating base, dynamic equations of the system are established. Taking a certain channel ferry as an example, a set of numerical calculation have been carried out for rolling response of the ship and displacement response of the slipping heavy load under common effect of synchro-slipping heavy loads and wave.展开更多
The floating foundation is designed to support a 1.5 MW wind turbine in 30 m water depth. With consideration of the viscous damping of foundation and heave plates, the amplitude-frequency response characteristics of t...The floating foundation is designed to support a 1.5 MW wind turbine in 30 m water depth. With consideration of the viscous damping of foundation and heave plates, the amplitude-frequency response characteristics of the foundation are studied. By taking into account the elastic effect of blades and tower, the classic quasi-steady blade-element/momentum（BEM） theory is used to calculate the aerodynamic elastic loads. A coupled dynamic model of the turbine-foundationmooring lines is established to calculate the motion response of floating foundation under Kaimal wind spectrum and regular wave by using the FAST codes. The model experiment is carried out to test damping characteristics and natural motion behaviors of the wind turbine system. The dynamics response is tested by considering only waves and the joint action of wind and waves. It is shown that the wind turbine system can avoid resonances under the action of wind and waves. In addition, the heave motion of the floating foundation is induced by waves and the surge motion is induced by wind. The action of wind and waves is of significance for pitch.展开更多
Multiple regression equations of liquidus temperature, electrical conductivity and bath density of the Na_3AlF_6-AlF_3-BaC1_2-NaCl system were obtained from experiments by using orthogonal regression method. The exper...Multiple regression equations of liquidus temperature, electrical conductivity and bath density of the Na_3AlF_6-AlF_3-BaC1_2-NaCl system were obtained from experiments by using orthogonal regression method. The experiments were carried out in 100A cell with low melting point electrolyte, the influences of cathodic current density, electrolytic temperature, density differences of bath and liquid aluminum on current efficiency (CE) were studied; when the electrolyte cryolite ratio was 2.5, w(BaC1_2) and w(NaCl) were 48% and 10%, respectively, CE reached 90% and specific energy consumption was 10.97k Wb/kg/kg. Because of the fact that aluminum metal obtained floated on the surface of molten electrolyte, this electrolysis method was then defined as low temperature aluminum floating electrolysis. The results showed that the new low temperature aluminum electrolysis process in the Na_3AlF_6-AlF_3-BaC1_2-NaCl bath system was practical and promising.展开更多
The internal friction of floating spline can cause self-excited vibration of a supercritical flexible rotor system.To address this issue,a high-efficiency dynamic modeling method is proposed to investigate the self-ex...The internal friction of floating spline can cause self-excited vibration of a supercritical flexible rotor system.To address this issue,a high-efficiency dynamic modeling method is proposed to investigate the self-excited vibration behavior and instability evolution of the rotor.Experiments are conducted to validate the theoretical results.The coupled dynamic equations for the rotor system connected with the floating spline are derived through the combination of finite element method and lumped parameter model.A hybrid numerical approach of precise integration and Runge-Kutta method is adopted to examine the effects of the friction coefficient of spline’s tooth surface,torque,and eccentricity on the self-excited vibration of the rotor system.The results show that the spline friction leads to negative damping and inputs energy into the rotor system under supercritical conditions,triggering self-excited vibration when the input energy exceeds a specific level.With the same parameters,the experimentally obtained axial trajectory and primary frequency components are consistent with the theoretical results,verifying the accuracy of the proposed theoretical model.This study can serve as a useful theoretical guide for the dynamic stability design of flexible rotor systems with the floating spline.展开更多
As a new type of marine structure,floating breakwater can provide suitable water area for coastal residents.In this paper,a multi-module floating breakwater with three cylinders was designed.According to the character...As a new type of marine structure,floating breakwater can provide suitable water area for coastal residents.In this paper,a multi-module floating breakwater with three cylinders was designed.According to the characteristics of each module,the elastic connector was created.The cabins with functions such as living,generating electricity and entertainment were arranged.A linear spring constrained design wave(LSCDW)method for strength analysis of floating marine structures with multi-module elastic connections was proposed.The numerical model was verified by 1:50 similarity ratio in the test tank.According to the analysis of design wave and extreme wave conditions,considering the mooring loads and environmental loads and connector loads,the overall strength of breakwater was analyzed by LSCDW method.These studies can provide new insights and theoretical guidance for the design of multi-module floating structures.展开更多
An innovative floating mooring system with two or more independent floating mooring platforms in the middle and one rigid platform on each side is proposed for improving efficiency and safety in shallow water. For thi...An innovative floating mooring system with two or more independent floating mooring platforms in the middle and one rigid platform on each side is proposed for improving efficiency and safety in shallow water. For this new system, most of collision energy is absorbed through the displacement of floating platforms. In order to illustrate the validity of the system, a series of model tests were conducted at a scale of 1:40. The coupled motion characteristics of the floating mooring platforms were discussed under regular and irregular waves, and the influences of wave direction and other characteristics on dynamic response of the system were analyzed. The results show that the mooring system is safest at 0° of wave incident angle, whereas the most dangerous mooring state occurs at 90° of wave incident angle. Motion responses increase with the increase of wave height, but are not linearly related to changes in wave height.展开更多
This study aimed to develop hydrophilicmatrix based controlled release gastroretentive drug delivery system of ofloxacin and conducting its in vitro and in vivo evaluations.Effervescent floating gastroretentive drug d...This study aimed to develop hydrophilicmatrix based controlled release gastroretentive drug delivery system of ofloxacin and conducting its in vitro and in vivo evaluations.Effervescent floating gastroretentive drug delivery system of ofloxacin was prepared utilizing Boxe Behnken statistical design with 3 factors,3 levels and 15 experimental trials.Formulation optimization was done by setting targets on selected responses.In vivo studies were carried out for the optimized formulation with 12 healthy human volunteers and obtained pharmacokinetic parameters were compared with themarketed once daily formulation,“Zanocin OD”.Optimized formulation showed satisfactory controlled in vitro drug release for more than 12 h with excellent buoyancy properties(floating lag time<1 min,floating duration>16 h).Optimized and marketed formulations were found to have similar in vitro release profile(f2¼79.22)and also were found to be bioequivalent.Serum ofloxacin concentration was well maintained above its reported minimum inhibitory concentrations for most of the pathogens for sufficiently longer duration.Cmax and AUC values of optimized formulation were found to be significantly higher than of marketed product despite their bioequivalence.Bettertherapeutic effect can be expected since ofloxacin exhibits concentration dependent killing.Hence,gastroretention can be a promising approach to enhance bioavailability of ofloxacin with narrow absorption window in upper GIT.展开更多
The high investment and low return of wave energy converters(WECs)seriously hamper their large-scale commercial application.The integration of WECs and floating breakwaters is conducive to enhance the competitiveness ...The high investment and low return of wave energy converters(WECs)seriously hamper their large-scale commercial application.The integration of WECs and floating breakwaters is conducive to enhance the competitiveness of wave energy conversion.The objective of this paper is to investigate the hydrodynamic performance of a WEC-breakwater integrated system combining an upstream oscillating water column(OWC)and a downstream oscillating buoy(OB)via numerical simulations and physical experiments.A nonlinear numerical wave flume using Star-CCM+software is employed to obtain calculated results,where a tiny transverse gap is set between the flume wall and the block surface to simulate a similar two-dimensional(2D)model.The corresponding physical experiments are also carried out in a practical wave flume to verified the numerical results.The comparison of the isolated and hybrid system shows that the hybrid design leads to the decreased conversion efficiency of each WEC,but improves the transmission performance of the hybrid system.The wave resonance between two devices causes the abrupt reduction of OWC efficiency and a positive correlation exists with the OB efficiency.The total efficiency of the hybrid system is raised by an optimal opening ratio,a shallow OWC draft and a short spacing distance.Except for the OWC draft,other design parameters have weak effect on the wave attenuation of the hybrid system.This paper can help understand hydrodynamics of the hybrid WECs integrated with breakwaters and improve their performances.展开更多
The present work is aimed to study the pharmacokinetic parameters of optimized repaglinide floating drug delivery system(FDDS) by 24 factorial designs,followed by comparison with a commercially available formulation.T...The present work is aimed to study the pharmacokinetic parameters of optimized repaglinide floating drug delivery system(FDDS) by 24 factorial designs,followed by comparison with a commercially available formulation.The main effects and interactions of formulation variables were studied by using normal and pareto charts.The optimized formulation shows a fickian diffusion drug release mechanism.Pharmacokinetic parameters of the designed drug delivery system were evaluated in rabbit models.Mean while a simple,specific high performance liquid chromatographic method was developed and validated as per biopharmaceutical specifications,the linearity was observed at the range of 110-550 ng/mL(r2 = 0.999).By using methanol-phosphate buffer(pH 2.5)(70:30,v/v) as mobile phase at the flow rate of 1.0 mL/min the validation shows a better retention time of 5.2 min for repaglinide.And the same validation method was used for pharmacokinetic profile analysis of repaglinide marketed products and FDDS.The comparative pharmacokinetic results such as tmax,half-life,area under the curve,mean residence times were increased significantly for the repaglinide in FDDS than the marketed product of repaglinide except Cmax and elimination rate constant.展开更多
Integrating wave energy converters(WECs)with offshore platforms offers numerous advantages,such as reducing wave loads,supplying energy to the platform,and cost-sharing in construction.This paper reports an experiment...Integrating wave energy converters(WECs)with offshore platforms offers numerous advantages,such as reducing wave loads,supplying energy to the platform,and cost-sharing in construction.This paper reports an experimental investigation focusing on the hydrodynamic characteristics of a proposed modular floating structure system integrated with WEC-type floating artificial reefs.The proposed system comprises several serially arranged hexagonal floating structures,anchored by tension legs,and integrated with outermost WEC-type floating artificial reefs.A simplified wave energy converter utilizing the relative pitch motion between adjacent modules for energy conversion was constructed in the scale model test.The effects of chain-type modular expansion on the multi-body motion response,mooring tension response,and WEC performance of the system have been thoroughly investigated.The experimental results indicate that increasing the number of hexagonal modules can notably reduce the system’s surge response,particularly under survival sea conditions.The connection of the outermost reef modules slightly increases the tension leg load of the adjacent module,whereas the tension leg load remains relatively consistent across the inner hexagonal modules.Furthermore,through a comparison of the dynamic responses of the hexagonal module connected and unconnected outermost reefs,the good performance in terms of energy conversion and wave attenuation of the WECtype floating artificial reef modules was effectively validated.The main results from this work can provide useful references for engineering applications involving modular floating structures integrated with WECs.展开更多
基金This project was supported by the National Natural Science Foundation of China (Grant No. 50039010)
文摘A new hybrid method of frequency domain and time domain is developed in this paper to predict the motion responses of a flexibly joint multi-body floating system to irregular waves. The main idea of the method is that the three-dimensional frequency method is used to obtain the hydrodynamic coefficients and the response equations are solved in time domain step by step. All the forces can be obtained at the same time. The motions and nonlinear mooring forces of a box type six-body floating system are predicted. A comparison of the theoretical method-based Solutions with experimental results has shown good agreement.
基金the Hi-Tech Research and Development Pro-gram (863) of China (Nos. 2006AA100301 and 2006BAD09A13) the Open Foundation of State Key Laboratory of Coastal Offshore Engineering of Dalian University of Technology (No. LP0604), China
文摘Numerical simulation and experimental tests were carried out to examine the hydrodynamic behaviors of a double-column floating system of gravity cage under wave conditions. A floating system of gravity cage can be treated as a small-sized floating structure when compared with the wavelengths. The main problem in calculating the wave loads on the small-sized floating structure is to obtain the reasonable force coefficients, which may differ from a submerged structure. In this paper, the floating system of gravity cage is simplified to a 2D problem, where the floating system is set symmetrically under wave conditions. The motion equations were deduced under wave conditions and a specific method was proposed to resolve the problem of wave forces acting on a small-sized floating system of gravity cage at water surface. Results of the numerical method were compared with those from model tests and the hydrodynamic coefficients Cn and Cr were studied. It is found that Cn ranges from 0.6 to 1.0 while Cr is between 0.4 and 0.6 in this study. The results are useful for research on the hydrodynamic behavior of the deep-water gravity sea cages.
文摘Polyester mooring has become increasing popular to serve as permanent station-keeping system for deepwater floating system during recent years. Comparing to the traditional steel wire mooring,polyester mooring provides significant benefits in deepwater,such as reduced installed capital expenditure (CAPEX) and smaller vertical loads on host platform. Polyester rope is a visco-elastic material,and its stiffness is nonlinear and affected by mean load,load range,loading period and loading history. There is a perception that the polyester stiffness model has significant impact on the floating system's performance. This paper presents a detailed description and comparison of two stiffness models and three analytic approaches,and provides a systematic study of the impact of polyester mooring stiffness modeling on the deepwater floating system performance.
基金supported by the National Key R&D Pro-gram of China(Grant No.2023YFE0114600)The National Natural Science Foundation of China(NSFC)(Grant No.52477029)Joint Laboratory of China-Morocco Green Energy and Advanced Materials,The Youth Innovation Team of Shaanxi Universities and The Xi’an City Science and Technology Project(No.23GXFW0070)。
文摘Floating photovoltaic(FPV)technology is emerging as a highly promising approach to accelerate decarbonization of the global economy,due to its higher power generation efficiency and lower land occupation.With the rapid development of FPV technology,the mechanical performance degradation of key components caused by the harsh marine environment has become a pressing issue,as it significantly contributes to failure behavior observed in FPV systems.A comprehensive compilation of the mechanical performance of key components in FPV systems is also currently unavailable.Here,the mechanical behavior of each structural component in FPV systems under harsh marine environments is systematically reviewed.It further emphasizes the synergistic effects of mechanical performance degradation among different components on the overall system.The drop-off rate(v)of normalized elongation at break(EAB)of polymer under the synergistic effect of various environmental factors increases from 7.5×10^(−4)h^(−1)to 21.8×10^(−4)h^(−1)compared with the single environmental stress.Moreover,the development of novel materials and innovative mechanical structures applied in FPV systems to enhance mechanical performance is discussed.The novel flexible PV modules applied in FPV systems minimize the loads acting on the mooring lines by 80%and increase power generation by 5%.Notably,this paper provides a theoretical foundation for developing standards of FPV systems,especially the establishment of standards related to the synergistic effects of the mechanical performance degradation of different key components on FPV systems.
基金supported by the Key Project of Shaanxi Natural Science Foundation,China(No.2023-JC-ZD-28)the Shaanxi Key Research and Development Program,China(No.2023GXLH-056).
文摘Floating photovoltaic(FPV)systems provide dual benefits in renewable energy generation and water resource utilization,supporting global decarbonization efforts.This study conducts a full life cycle assessment(LCA)of FPV systems,covering material production,construction,operation,and decommissioning stages.Particular attention was given to ecological risks,an often overlooked aspect in previous environmental evaluations.A structured ecological risk matrix is developed integrating physical,chemical,and biological indicators to evaluate environmental disturbances caused by FPV systems.The framework was applied to eight representative water bodies in China,including Taihu Lake(characterized by high nutrient loading),Danjiangkou Reservoir(a major drinking water source),and Poyang Lake(an ecologically sensitive wetland).Each site is evaluted using a semi-quantitative scoring system based on ecological sensitivity and FPV disturbance potential.Risk levels were classified to guide deployment suitability(0-6),identify high-risk areas,and support mitigation strategies.The findings revealed significant spatial heterogeneity in ecosystem vulnerability and highlighted the lack of standardized protocols for ecological risk assessment in FPV projects.In response,this study proposed context-specific design recommendations,including adjustments to module density,transparency,and anchoring methods,to minimize ecological impacts.This research provides a transferable tool for incorporating ecological metrics into FPV planning and regulatory review,particularly in freshwater ecosystems.It contributes to the development of risk-informed deployment guidelines and emphasizes the need for long-term ecological monitoring in FPV expansion.
基金Supported by Special Fund for Guangdong Modern Agriculture Industrial System Construction (Guangdong Agriculture 2009-380 )Key Agriculture Project of Guangdong Science and Technology Department (2009B020202003 )+1 种基金Key Agriculture Project of Guangdong Science and Technology Department (2009B020304002)Agriculture Brainstorm Project of Panyu District Guangzhou,Guangdong Province (2010-Z-82-1)~~
文摘[Objective] The aim was to investigate different effects of two pH-regulating acids on the root morphology and other physiological growth of Lactuca sativa L.in floating plug transplant system.[Method] HNO3 and H2SO4 were used to adjust pH condition of various nutrient concentrations in lettuce floating transplant system,the effect of two acid treatments on root traits of lettuce were investigated.[Result] These two acids made different effects on root system under a series of nutrient gradients.Under HNO3 treatment,the fresh weight of shoot and root were increased with growth of nutrient concentration;root preformed best when EC was 1.0 μs/cm.Under H2SO4 treatment,when EC was 0.8 μs/cm,the total root length and root surface area,projected area,root volume of lettuce were 344.8 cm,40.9 cm2,13.0 cm2,0.4 m3,respectively,which were significantly higher than those in HNO3 treatment.Compared the influences of acid treatments under same nutrient concentration,the result showed that H2SO4 treatment increased root/shoot ratio and all other root morphological characteristics;however,HNO3 treatment promoted the growth of shoot and lateral root,increased transplanting efficiency and facilitated realizing high yield after transplanted into open-field.[Conclusion] This study will provide theoretical reference for improving plug transplant technology of lettuce.
基金supported by the National Natural Science Foundation of China(No.40873057)the Special of Science and Technology Innovation and Achievement Transformation of Jiangsu,China(No.BE2008677)+1 种基金the Natural Science Foundation for the Colleges and Universities in Jiangsu Province(No.10KJB610001)the Scientific Research Foundation for the Talents in Jiangsu University(No.09JDG050)
文摘The ecological floating bed system is a natural alternative to technical methods of wastewater treatment and involves complex processes induced by plants or microorganisms in the wastewater. This study aimed to identify nutrient concentration variations during Oenanthe javanica （Blume） DC growth and decay in the ecological floating bed system. Results showed that the third-order polynomial equation was suitable to describe pollutant concentration changes, showing that the effect of O. javanica ecological floating bed system on polluted water could be divided into the purification phase and decay phase. During the purification phase, nutrient concentrations rapidly decreased because O. javanica influenced water microbial communities and water physical parameters （i.e., dissolved oxygen, pH, and temperature）, and had a direct uptake of nutrients. However, during the decay phase, nitrogen and phosphorus concentrations in the plant tissues decreased, and these lost nutrients ultimately transferred to water and led to water quality deterioration. Results also showed that the uptake and storage of O. javanica in nutrients were temporary and the plant served only as media of the nutrients removed from the water. Under these circumstances, harvesting was an appropriate intervention to improve the treatment efficiency of O. javanica ecological floating bed system.
文摘As a promising renewable energy,offshore wind energy currently is gaining more attention,by which the economic and efficient operation of floating wind turbine systems is a potential research direction.This study is primarily devoted to the analysis of dynamic response of the NREL-5 MW reference wind turbine supported by an OC3-Hywind SPAR-type platform using a recompiled code which combines FAST with WAMIT.To verify the reliability of the recompiled code,the free decay motions of a floating wind turbine system in still water are examined with satisfactory results.After that,thirteen scenarios with different angles between wind and wave from 0°to 90°are investigated.The dynamic responses of the turbine system in various degrees of freedom(DOFs)for different incident wind/wave directions are presented in both time and frequency domains via the fast Fourier transform.
基金Foundation item： Supported by the 111 Project under Grant No.B07019, and the National Natural Science Foundation of China under Grant No.50979020.
文摘The development of offshore wind farms was originally carried out in shallow water areas with fixed （seabed mounted） structures. However, countries with limited shallow water areas require innovative floating platforms to deploy wind turbines offshore in order to harness wind energy to generate electricity in deep seas. The performances of motion and mooring system dynamics are vital to designing a cost effective and durable floating platform. This paper describes a numerical model to simulate dynamic behavior of a new semi-submersible type floating offshore wind turbine （FOWT） system. The wind turbine was modeled as a wind block with a certain thrust coefficient, and the hydrodynamics and mooting system dynamics of the platform were calculated by SESAM soRware. The effect of change in environmental conditions on the dynamic response of the system under wave and wind loading was examined. The results indicate that the semi-submersible concept has excellent performance and SESAM could be an effective tool for floating wind turbine design and analysis.
文摘In this paper, the impact analysis of air gap concerning the parameters of mooring system for the semi-submersible platform is conducted. It is challenging to simulate the wave, current and wind loads of a platform based on a model test simultaneously. Furthermore, the dynamic equivalence between the truncated and full-depth mooring system is still a tuff work. However, the wind and current loads can be tested accurately in wind tunnel model. Furthermore, the wave can be simulated accurately in wave tank test. The full-scale mooring system and the all environment loads can be simulated accurately by using the numerical model based on the model tests simultaneously. In this paper, the air gap response of a floating platform is calculated based on the results of tunnel test and wave tank. Meanwhile, full-scale mooring system, the wind, wave and current load can be considered simultaneously. In addition, a numerical model of the platform is tuned and validated by ANSYS AQWA according to the model test results. With the support of the tuned numerical model, seventeen simulation cases about the presented platform are considered to study the wave, wind, and current loads simultaneously. Then, the impact analysis studies of air gap motion regarding the length, elasticity, and type of the mooring line are performed in the time domain under the beam wave, head wave, and oblique wave conditions.
基金the National Natural Science Foundation of China(50309018).
文摘Common effect of wave and slip of internal heavy load will make rolling of the roll-on ship serious. This is one of the important reasons for overturn of ro-ro ships. The multibodies System with a floating base is composed of ro-ro ship and slipping heavy load. This paper takes the rolling angle of the ship and the transverse displacement of the heavy load on desk as two freedoms. Making use of analysis of apparent gravitation and apparent buoyancy, the wave rolling moment is derived. By use of dynamic method of multibodies system with a floating base, dynamic equations of the system are established. Taking a certain channel ferry as an example, a set of numerical calculation have been carried out for rolling response of the ship and displacement response of the slipping heavy load under common effect of synchro-slipping heavy loads and wave.
基金financially supported by the National Basic Research Program of China(973 ProgramGrant Nos.2014CB046801 and 2014CB046805)
文摘The floating foundation is designed to support a 1.5 MW wind turbine in 30 m water depth. With consideration of the viscous damping of foundation and heave plates, the amplitude-frequency response characteristics of the foundation are studied. By taking into account the elastic effect of blades and tower, the classic quasi-steady blade-element/momentum（BEM） theory is used to calculate the aerodynamic elastic loads. A coupled dynamic model of the turbine-foundationmooring lines is established to calculate the motion response of floating foundation under Kaimal wind spectrum and regular wave by using the FAST codes. The model experiment is carried out to test damping characteristics and natural motion behaviors of the wind turbine system. The dynamics response is tested by considering only waves and the joint action of wind and waves. It is shown that the wind turbine system can avoid resonances under the action of wind and waves. In addition, the heave motion of the floating foundation is induced by waves and the surge motion is induced by wind. The action of wind and waves is of significance for pitch.
基金The project was financially supported by the National Natural Science Foundation of China! (Gmnt No.59574018)China Postdocto
文摘Multiple regression equations of liquidus temperature, electrical conductivity and bath density of the Na_3AlF_6-AlF_3-BaC1_2-NaCl system were obtained from experiments by using orthogonal regression method. The experiments were carried out in 100A cell with low melting point electrolyte, the influences of cathodic current density, electrolytic temperature, density differences of bath and liquid aluminum on current efficiency (CE) were studied; when the electrolyte cryolite ratio was 2.5, w(BaC1_2) and w(NaCl) were 48% and 10%, respectively, CE reached 90% and specific energy consumption was 10.97k Wb/kg/kg. Because of the fact that aluminum metal obtained floated on the surface of molten electrolyte, this electrolysis method was then defined as low temperature aluminum floating electrolysis. The results showed that the new low temperature aluminum electrolysis process in the Na_3AlF_6-AlF_3-BaC1_2-NaCl bath system was practical and promising.
基金supported by the National Natural Science Foundation of China,China(No.52005253)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China,China(No.22KJB130004)+2 种基金the Natural Science Foundation of Jiangsu Province,China(No.BK20200426)the Postdoctoral Science Foundation of Jiangsu Province,China(No.2021K075A)the National Key Laboratory of Science and Technology on Helicopter Transmission,China(No.HTL-O-21G08)。
文摘The internal friction of floating spline can cause self-excited vibration of a supercritical flexible rotor system.To address this issue,a high-efficiency dynamic modeling method is proposed to investigate the self-excited vibration behavior and instability evolution of the rotor.Experiments are conducted to validate the theoretical results.The coupled dynamic equations for the rotor system connected with the floating spline are derived through the combination of finite element method and lumped parameter model.A hybrid numerical approach of precise integration and Runge-Kutta method is adopted to examine the effects of the friction coefficient of spline’s tooth surface,torque,and eccentricity on the self-excited vibration of the rotor system.The results show that the spline friction leads to negative damping and inputs energy into the rotor system under supercritical conditions,triggering self-excited vibration when the input energy exceeds a specific level.With the same parameters,the experimentally obtained axial trajectory and primary frequency components are consistent with the theoretical results,verifying the accuracy of the proposed theoretical model.This study can serve as a useful theoretical guide for the dynamic stability design of flexible rotor systems with the floating spline.
基金the National Natural Science Foundation of China(No.52071161)。
文摘As a new type of marine structure,floating breakwater can provide suitable water area for coastal residents.In this paper,a multi-module floating breakwater with three cylinders was designed.According to the characteristics of each module,the elastic connector was created.The cabins with functions such as living,generating electricity and entertainment were arranged.A linear spring constrained design wave(LSCDW)method for strength analysis of floating marine structures with multi-module elastic connections was proposed.The numerical model was verified by 1:50 similarity ratio in the test tank.According to the analysis of design wave and extreme wave conditions,considering the mooring loads and environmental loads and connector loads,the overall strength of breakwater was analyzed by LSCDW method.These studies can provide new insights and theoretical guidance for the design of multi-module floating structures.
基金the support of the National Natural Science Foundation of China (Grant No. 51309179)the National High Technology Research and Development Program of China (863 Program, Grant No. 2012AA051705)+2 种基金the International S&T Cooperation Program of China (Grant No. 2012DFA70490)the State Key Laboratory of Hydraulic Engineering Simulation and Safety (Tianjin University)the Tianjin Municipal Natural Science Foundation (Grant Nos. 14JCQNJC07000 and 13JCYBJC19100)
文摘An innovative floating mooring system with two or more independent floating mooring platforms in the middle and one rigid platform on each side is proposed for improving efficiency and safety in shallow water. For this new system, most of collision energy is absorbed through the displacement of floating platforms. In order to illustrate the validity of the system, a series of model tests were conducted at a scale of 1:40. The coupled motion characteristics of the floating mooring platforms were discussed under regular and irregular waves, and the influences of wave direction and other characteristics on dynamic response of the system were analyzed. The results show that the mooring system is safest at 0° of wave incident angle, whereas the most dangerous mooring state occurs at 90° of wave incident angle. Motion responses increase with the increase of wave height, but are not linearly related to changes in wave height.
文摘This study aimed to develop hydrophilicmatrix based controlled release gastroretentive drug delivery system of ofloxacin and conducting its in vitro and in vivo evaluations.Effervescent floating gastroretentive drug delivery system of ofloxacin was prepared utilizing Boxe Behnken statistical design with 3 factors,3 levels and 15 experimental trials.Formulation optimization was done by setting targets on selected responses.In vivo studies were carried out for the optimized formulation with 12 healthy human volunteers and obtained pharmacokinetic parameters were compared with themarketed once daily formulation,“Zanocin OD”.Optimized formulation showed satisfactory controlled in vitro drug release for more than 12 h with excellent buoyancy properties(floating lag time<1 min,floating duration>16 h).Optimized and marketed formulations were found to have similar in vitro release profile(f2¼79.22)and also were found to be bioequivalent.Serum ofloxacin concentration was well maintained above its reported minimum inhibitory concentrations for most of the pathogens for sufficiently longer duration.Cmax and AUC values of optimized formulation were found to be significantly higher than of marketed product despite their bioequivalence.Bettertherapeutic effect can be expected since ofloxacin exhibits concentration dependent killing.Hence,gastroretention can be a promising approach to enhance bioavailability of ofloxacin with narrow absorption window in upper GIT.
基金supported by the National Natural Science Foundation of China(Grant Nos.52111530137 and 52025112)the State Key Laboratory of Ocean Engineering,China(Shanghai Jiao tong University)(Grant No.1905).
文摘The high investment and low return of wave energy converters(WECs)seriously hamper their large-scale commercial application.The integration of WECs and floating breakwaters is conducive to enhance the competitiveness of wave energy conversion.The objective of this paper is to investigate the hydrodynamic performance of a WEC-breakwater integrated system combining an upstream oscillating water column(OWC)and a downstream oscillating buoy(OB)via numerical simulations and physical experiments.A nonlinear numerical wave flume using Star-CCM+software is employed to obtain calculated results,where a tiny transverse gap is set between the flume wall and the block surface to simulate a similar two-dimensional(2D)model.The corresponding physical experiments are also carried out in a practical wave flume to verified the numerical results.The comparison of the isolated and hybrid system shows that the hybrid design leads to the decreased conversion efficiency of each WEC,but improves the transmission performance of the hybrid system.The wave resonance between two devices causes the abrupt reduction of OWC efficiency and a positive correlation exists with the OB efficiency.The total efficiency of the hybrid system is raised by an optimal opening ratio,a shallow OWC draft and a short spacing distance.Except for the OWC draft,other design parameters have weak effect on the wave attenuation of the hybrid system.This paper can help understand hydrodynamics of the hybrid WECs integrated with breakwaters and improve their performances.
文摘The present work is aimed to study the pharmacokinetic parameters of optimized repaglinide floating drug delivery system(FDDS) by 24 factorial designs,followed by comparison with a commercially available formulation.The main effects and interactions of formulation variables were studied by using normal and pareto charts.The optimized formulation shows a fickian diffusion drug release mechanism.Pharmacokinetic parameters of the designed drug delivery system were evaluated in rabbit models.Mean while a simple,specific high performance liquid chromatographic method was developed and validated as per biopharmaceutical specifications,the linearity was observed at the range of 110-550 ng/mL(r2 = 0.999).By using methanol-phosphate buffer(pH 2.5)(70:30,v/v) as mobile phase at the flow rate of 1.0 mL/min the validation shows a better retention time of 5.2 min for repaglinide.And the same validation method was used for pharmacokinetic profile analysis of repaglinide marketed products and FDDS.The comparative pharmacokinetic results such as tmax,half-life,area under the curve,mean residence times were increased significantly for the repaglinide in FDDS than the marketed product of repaglinide except Cmax and elimination rate constant.
基金financially supported by the National Natural Science Foundation of China(Grant No.52161041)the Natural Science Foundation of Hainan Province(Grant No.520RC552).
文摘Integrating wave energy converters(WECs)with offshore platforms offers numerous advantages,such as reducing wave loads,supplying energy to the platform,and cost-sharing in construction.This paper reports an experimental investigation focusing on the hydrodynamic characteristics of a proposed modular floating structure system integrated with WEC-type floating artificial reefs.The proposed system comprises several serially arranged hexagonal floating structures,anchored by tension legs,and integrated with outermost WEC-type floating artificial reefs.A simplified wave energy converter utilizing the relative pitch motion between adjacent modules for energy conversion was constructed in the scale model test.The effects of chain-type modular expansion on the multi-body motion response,mooring tension response,and WEC performance of the system have been thoroughly investigated.The experimental results indicate that increasing the number of hexagonal modules can notably reduce the system’s surge response,particularly under survival sea conditions.The connection of the outermost reef modules slightly increases the tension leg load of the adjacent module,whereas the tension leg load remains relatively consistent across the inner hexagonal modules.Furthermore,through a comparison of the dynamic responses of the hexagonal module connected and unconnected outermost reefs,the good performance in terms of energy conversion and wave attenuation of the WECtype floating artificial reef modules was effectively validated.The main results from this work can provide useful references for engineering applications involving modular floating structures integrated with WECs.
