In this paper, the buoyancy, kinetic properties and stability of air floated structures have been studied by theoretical and experimental methods. The equations for calculation of the buoyancy of the air floated buoy ...In this paper, the buoyancy, kinetic properties and stability of air floated structures have been studied by theoretical and experimental methods. The equations for calculation of the buoyancy of the air floated buoy are derived according to the Boyler law and the equilibrium equations of the air floated structure are established. Through simplification of the air floated structure as a single freedom rigid body and spring system, the natural period of heaving and some kinetic properties are discussed. In the stability analysis, the formulas for calculation of the meta centric height are presented. The theoretical results are in good agreement with the data observed from the model test and prototype test. The air buoyancy decrease coefficient presented in this paper has a large influence on the floating state, stability and dynamic properties of the air floated structure. The stability of the air floated structure can also be judged by the parameter of meta centric height, and calculations show that the air floated structure is less stable than the conventional float.展开更多
The large-diameter cylinder structure, which is made of large successive bottomless cylinders placed on foundation bed or partly driven into soil, is a recently developed retaining structure in China. It can be used i...The large-diameter cylinder structure, which is made of large successive bottomless cylinders placed on foundation bed or partly driven into soil, is a recently developed retaining structure in China. It can be used in port, coastal and offshore works. The method for stability analysis of the large-diameter cylinder structure, especially for stability analysis of the embedded large-diameter cylinder structure, is an important issue. In this paper, an idea is presented that is, embedded large-diameter cylinder quays can be divided into two types, i.e. the gravity wall type and the cylinder pile wall type. A method for stability analysis of the large-diameter cylinder quay of the cylinder pile wall type is developed and a method for stability analysis of the large-diameter cylinder quay of the gravity wall type is also proposed. The effect of significant parameters on the stability of the large-diameter cylinder quay of the cylinder pile wall type is investigated through numerical calculation.展开更多
The concept of candidate particle set is introduced in the MPS gridless numerical method to generate neighboring particle set ma- trix, which can reduce the CPU time to 1/11 of that before introduction. The Bi-CGSTAB ...The concept of candidate particle set is introduced in the MPS gridless numerical method to generate neighboring particle set ma- trix, which can reduce the CPU time to 1/11 of that before introduction. The Bi-CGSTAB （bi-conjugate gradient stabilized） algorithm is applied to solving the Poisson pressure equation, by which the solving speed is significantly accelerated. The process of solitary waves propagating over a numerical flume and interacting with a vertical wall is simulated. The simulated results of water surface elevation are in good agreement with the analytical solution as well as the measured data. The predicted maximum values of the run-up of solitary waves with various relative incident wave heights agree well with the measured results.展开更多
An embedded cylinder is a large-diameter cylinder embedded in a soil foundation. The state of failure of such an embedded cylindrical structure shows large deflection instead of slide and overturn of the traditional g...An embedded cylinder is a large-diameter cylinder embedded in a soil foundation. The state of failure of such an embedded cylindrical structure shows large deflection instead of slide and overturn of the traditional gravity type of structure placed on a rubble base or foundation base. The critical value of deflection of the embedded cylindrical structure, which is the maximum allowable deflection for stability calculation of the cylinder, is a vital control value. Through investigation on deflection and soil pressures on an embedded cylinder by model experiments, the variations of the angle of rotation θ of a cylinder with effective anti-overturning ratio η and moment MH of thrust are discussed. On the basis of experimental study, the critical value of deflection of the cylindrical structure is proposed in the paper. Meanwhile, the formulas for calculating deflection of cylinders are derived.展开更多
The breakwater with top sealed, shallow and wide penetrating box foundations is a new type of structure, applicable to deep water and soft seabed. The relations of horizontal and vertical bearing capacities of the bo...The breakwater with top sealed, shallow and wide penetrating box foundations is a new type of structure, applicable to deep water and soft seabed. The relations of horizontal and vertical bearing capacities of the box foundation structure as well as the instability induced failure modes to its dimensions and external loads are discussed through static model tests and wave tests. The mechanical properties of the stability of the box foundation are similar to those of embedded rigid foundations, i.e. the vertical stresses at the bottom of the box are distributed in a linear pattern under the action of vertical loads, and passive and active soil pressures are developed at the front and back sides of the box under the action of horizontal loads; there are two instability induced failure modes of the foundation structure-horizontal slide along the box base and tilting due to insufficient local vertical bearing capacity of the soil beneath the box base. The stability of box foundations can be analyzed by use of the methods applied to analysis of the embedded rigid foundations. To increase the width of the box is the most effective way to improve the stability of box foundations.展开更多
Sliding is one of the principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. Herein, the mass-spring-dashpot model of caisson-base system is u...Sliding is one of the principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. Herein, the mass-spring-dashpot model of caisson-base system is used to simulate the vibrating-sliding motion of the caisson under various types of breaking wave impact forces, i.e., single peak impact force, double peak impact force, and shock-damping oscillation impact force. The effects of various breaking wave impacts and the sliding motion on the dynamic response behaviors of caisson breakwaters are investigated and the calculation of relevant system parameters is discussed. It is shown that the dynamic responses of the caisson are significantly different under different types of breaking wave impact forces even when the amplitudes of impact forces are equal. The amplitude of dynamic response of the caisson is lower under single peak impact excitation than that under double peak impact or shock-damping oscillation impact excitation. Though the displacement of the caisson is large due to sliding, the rotation, the sliding force and the overturning moment of the caisson are significantly reduced.展开更多
The Eocene Sokor1 Formation is proven oil reservoir rocks in the Termit sub-basin. These sandstone intervals are deeply buried, highly heterogeneous in character and characterized by Low Contrast Low Resistivity (LCLR...The Eocene Sokor1 Formation is proven oil reservoir rocks in the Termit sub-basin. These sandstone intervals are deeply buried, highly heterogeneous in character and characterized by Low Contrast Low Resistivity (LCLR) log responses. Petrophysical and quantitative well-based rock physics interpretations were integrated for property estimations, fluid and lithology typing in reservoir characterization. Six (6) reservoir sandstone intervals were identified, delineated and correlated across five (5) wells. The estimated petrophysical properties showed that the Eocene Sokor1 sandstones have averagely good reservoir properties with sand_5 interval exhibiting exceptional reservoir properties. <i><span style="font-family:Verdana;">V</span><sub><span style="font-family:Verdana;">p</span></sub><span style="font-family:Verdana;">/V</span><sub><span style="font-family:Verdana;">s</span></sub></i><span style="font-family:Verdana;"> vs. AI and </span><i><span style="font-family:Verdana;">μρ</span></i><span style="font-family:Verdana;"> vs. </span><i><span style="font-family:Verdana;">λρ</span></i><span style="font-family:Verdana;"> elastic cross-plots color coded with reservoir properties (</span><i><span style="font-family:Verdana;">V</span><sub><span style="font-family:Verdana;">sh</span></sub></i><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;"><span style="white-space:nowrap;">Φ</span></span></i><span style="font-family:Verdana;">), show distinct and well separated data clusters signifying hydrocarbon bearing sandstones, brine sandstones and shales/mudstones in the 3D crossplot planes with varying seismic elastic property values in each well thereby, enhancing reservoir characterization and providing information’s about the burial history, reservoir quality and property distribution in the sub-basin. The analys</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">is</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> suggests that, although the reservoir interval has averagely good petrophysical properties in all wells, the seismic elastic crossplots show that these properties are much better distributed in wells 2 and 3 than in wells 4, 5 and 9. Therefore, sand_5 reservoir interval in wells 2 and 3 </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">is</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> likely to be more hydrocarbon bearing and productive than wells 4, 5 and 9 in the sub-basin.</span></span></span>展开更多
In this paper, the theoretical analysis and experimental studies are employed to investigate the reflection characteristics of partial standing waves caused by wave overtopping and sloping top of structures. Based on ...In this paper, the theoretical analysis and experimental studies are employed to investigate the reflection characteristics of partial standing waves caused by wave overtopping and sloping top of structures. Based on the principle of conservation of wave energy flux, the third-order Stokes wave theory is used to formulate the reflection coefficient at wave overtopping; the calculation results are regressed into an applied expression. A series of experiments of wave reflection for a vertical-wall structure with chamfered and overhanging upper sections are carried out to investigate the influence of top slope on wave reflection. The regularity of variation of wave reflection in this case is analysed based on the experimental results.展开更多
Wave field around Taipei Port is studied. Using marine radar as a monitoring device, sequences of the wave field images were obtained on an hourly basis. A 3D-FFT was applied to the image sequences leading to the so-c...Wave field around Taipei Port is studied. Using marine radar as a monitoring device, sequences of the wave field images were obtained on an hourly basis. A 3D-FFT was applied to the image sequences leading to the so-called intensity wavenumber-frequency spectrum. Wave field information can then be extracted from these spectra and compared with on-site measurements. It is shown that, when the prevailing winds are weak, estimated wave heights agree miserably with those measured. On the other hand, when the winds are relatively strong, our estimates follow closely with the trends, but are, in general, lower than measured. Possible reasons leading to these discrepancies are discussed.展开更多
This article discusses the problems existing in the teaching of Logistics and the urgency of its curriculum reform,introduces the concept of outcome-based education(OBE)into the teaching process of Logistics,designs t...This article discusses the problems existing in the teaching of Logistics and the urgency of its curriculum reform,introduces the concept of outcome-based education(OBE)into the teaching process of Logistics,designs the teaching in a reverse direction guided by the results,and implements the teaching design in the form of flipped classroom.A“student-centered”teaching process endows students with stronger autonomy and initiative and encourages them to cooperate with each other.This teaching process provides new ideas and methods for the teaching reform of Logistics as well as the cultivation of excellent logistics talents.展开更多
Fluorescence microscopy is indispensable in life science research,yet denoising remains challenging due to varied biological samples and imaging conditions.We introduce a wavelet-enhanced transformer based on DnCNN th...Fluorescence microscopy is indispensable in life science research,yet denoising remains challenging due to varied biological samples and imaging conditions.We introduce a wavelet-enhanced transformer based on DnCNN that fuses wavelet preprocessing with a dual-branch transformer-convolutional neural network(CNN)architecture.Wavelet decomposition separates highand low-frequency components for targeted noise reduction;the CNN branch restores local details,whereas the transformer branch captures global context;and an adaptive loss balances quantitative fidelity with perceptual quality.On the fluorescence microscopy denoising benchmark,our method surpasses leading CNNand transformer-based approaches,improving peak signal-to-noise ratio by 2.34%and 0.88%and structural similarity index measure by 0.53%and 1.07%,respectively.This framework offers enhanced generalization and practical gains for fluorescence image denoising.展开更多
A numerical model is developed for dynamic analysis of large-cylinder breakwaters embedded in soft soil. In the model, the large cylinder is taken as a rigid body divided into elements and the soft soil is replaced by...A numerical model is developed for dynamic analysis of large-cylinder breakwaters embedded in soft soil. In the model, the large cylinder is taken as a rigid body divided into elements and the soft soil is replaced by discrete 3D nonlinear spring-dashpot systems. The numerical model is used to simulate the dynamic response of a large-cylinder breakwater to breaking wave excitation. The effects of the dynamic stress-strain relationship models of the soil, the radius and embedded depth of the cylinder, the nonlinear behaviors of the soil, and the limit strength condition of the soil on the dynamic responses of the large-cylinder structure are investigated with an example given. It is indicated that the above-mentioned factors have significant effects on the dynamic responses of an embedded large cylinder breakwater under breaking wave excitation.展开更多
Vibrating, sliding and uplift rocking are three elementary motion types of caisson breakwaters. The dynamic model and the numerical simulation method of vibrating-sliding-uplift rocking coupled motion of caisson break...Vibrating, sliding and uplift rocking are three elementary motion types of caisson breakwaters. The dynamic model and the numerical simulation method of vibrating-sliding-uplift rocking coupled motion of caisson breakwaters are developed. The histories of displacement, rotation, sliding force and overturning moment of a caisson breakwater under the excitation of breaking wave impact are calculated for the motion models of vibrating, vibrating-sliding, vibrating-uplift rocking and vibrating-sliding-uplift rocking. The effects of various motion models on the stability of caisson breakwaters are investigated. The feasibility of the dynamic design idea that the sliding motion and the uplift rocking motion of caisson breakwaters are allowed under the excitation of breaking wave impact is discussed.展开更多
An integrated storm surge modeling and traffic analysis were conducted in this study to assess the effectiveness of hurricane evacuations through a case study of Hurricane Irma.The Category 5 hurricane in 2017 caused ...An integrated storm surge modeling and traffic analysis were conducted in this study to assess the effectiveness of hurricane evacuations through a case study of Hurricane Irma.The Category 5 hurricane in 2017 caused a record evacuation with an estimated 6.8 million people relocating statewide in Florida.The Advanced Circulation(ADCIRC)model was applied to simulate storm tides during the hurricane event.Model validations indicated that simulated pressures,winds,and storm surge compared well with observations.Model simulated storm tides and winds were used to estimate the area affected by Hurricane Irma.Results showed that the storm surge and strong wind mainly affected coastal counties in south-west Florida.Only moderate storm tides(maximum about 2.5 m)and maximum wind speed about 115 mph were shown in both model simulations and Federal Emergency Management Agency(FEMA)post-hurricane assessment near the area of hurricane landfall.Storm surges did not rise to the 100-year flood elevation level.The maximum wind was much below the design wind speed of 150–170 mph(Category 5)as defined in Florida Building Code(FBC)for south Florida coastal areas.Compared with the total population of about 2.25 million in the six coastal counties affected by storm surge and Category 1–3 wind,the statewide evacuation of approximately 6.8 million people was found to be an over-evacuation due mainly to the uncertainty of hurricane path,which shifted from south-east to south-west Florida.The uncertainty of hurricane tracks made it difficult to predict the appropriate storm surge inundation zone for evacuation.Traffic data were used to analyze the evacuation traffic patterns.In south-east Florida,evacuation traffic started 4 days before the hurricane’s arrival.However,the hurricane path shifted and eventually landed in south-west Florida,which caused a high level of evacuation traffic in south-west Florida.Over-evacuation caused Evacuation Traffic Index(ETI)to increase to 200%above normal conditions in some sections of highways,which reduced the effectiveness of evacuation.Results from this study show that evacuation efficiency can be improved in the future by more accurate hurricane forecasting,better public awareness of real-time storm surge and wind as well as integrated storm surge and evacuation modeling for quick response to the uncertainty of hurricane forecasting.展开更多
Beaches play a pivotal role in supporting the socio-economic sector,particularly within the’Sun,Sea,and Sand’(3S)tourism model.Valued for their ecosystem services,these coastal landforms are among the most dynamic a...Beaches play a pivotal role in supporting the socio-economic sector,particularly within the’Sun,Sea,and Sand’(3S)tourism model.Valued for their ecosystem services,these coastal landforms are among the most dynamic and vulnerable environments,facing significant pressure from various climate challenges,which is further intensified by extensive anthropic exploitation.Their sustainable use is intrinsically linked to balancing the 3Ps:Planet,People,and Profit.To address the need for protection and sustainable utilization of coastal areas,the European Union has introduced the Protocol on Integrated Coastal Zone Management(ICZM)in the Mediterranean,specifically recommending in Article 8(2)the establishment of a setback buffer zone where permanent constructions are prohibited.This paper explores the application of risk mapping in the context of coastal setback policies,focusing on their effectiveness in managing beach retreat and adapting to climate change,particularly rising sea levels.The study examines selected beach areas in Peloponnese,Greece,influenced by various socio-economic factors.Through this analysis,the paper aims to contribute to the discourse on coastal management strategies that balance environmental sustainability with socio-economic benefits.展开更多
Wave propagation problems in orthotropic media are studied jointly by analytical and experimental methods in this paper. Dynamic orthotropic photoelasticity, which studies experimentally the dynamic behavior of orthot...Wave propagation problems in orthotropic media are studied jointly by analytical and experimental methods in this paper. Dynamic orthotropic photoelasticity, which studies experimentally the dynamic behavior of orthotropic materials on a macroscopic scale by employing orthotropic birefringent materials, is established. A dynamic stress-optic law for orthotropic birefringent materials is postulated and practical methods of calibrating dynamic mechanical constants and dynamic stress-fringe values are proposed. Meanwhile, time domain boundary element method (BEM) for wave propagation in orthotropic media, is also presented based on the theory of elastodynamics. A scheme of stress calculations that is necessary for strength analysis is established. The paper stresses on the applications in wavepropagation problems in orthotropic media by demonstrating three examples. The semi-infinite orthotropic plates with and without a circular hole modeled by a unidirectional fiber-reinforced composite under impact展开更多
文摘In this paper, the buoyancy, kinetic properties and stability of air floated structures have been studied by theoretical and experimental methods. The equations for calculation of the buoyancy of the air floated buoy are derived according to the Boyler law and the equilibrium equations of the air floated structure are established. Through simplification of the air floated structure as a single freedom rigid body and spring system, the natural period of heaving and some kinetic properties are discussed. In the stability analysis, the formulas for calculation of the meta centric height are presented. The theoretical results are in good agreement with the data observed from the model test and prototype test. The air buoyancy decrease coefficient presented in this paper has a large influence on the floating state, stability and dynamic properties of the air floated structure. The stability of the air floated structure can also be judged by the parameter of meta centric height, and calculations show that the air floated structure is less stable than the conventional float.
基金by the National Natural Science Foundation of China(Grant No.59679003)the Natural Science Foundation of Tianjin(Grant No.973606311)
文摘The large-diameter cylinder structure, which is made of large successive bottomless cylinders placed on foundation bed or partly driven into soil, is a recently developed retaining structure in China. It can be used in port, coastal and offshore works. The method for stability analysis of the large-diameter cylinder structure, especially for stability analysis of the embedded large-diameter cylinder structure, is an important issue. In this paper, an idea is presented that is, embedded large-diameter cylinder quays can be divided into two types, i.e. the gravity wall type and the cylinder pile wall type. A method for stability analysis of the large-diameter cylinder quay of the cylinder pile wall type is developed and a method for stability analysis of the large-diameter cylinder quay of the gravity wall type is also proposed. The effect of significant parameters on the stability of the large-diameter cylinder quay of the cylinder pile wall type is investigated through numerical calculation.
基金This work was supported by the Natural Science Foundation of China under No.50479047.
文摘The concept of candidate particle set is introduced in the MPS gridless numerical method to generate neighboring particle set ma- trix, which can reduce the CPU time to 1/11 of that before introduction. The Bi-CGSTAB （bi-conjugate gradient stabilized） algorithm is applied to solving the Poisson pressure equation, by which the solving speed is significantly accelerated. The process of solitary waves propagating over a numerical flume and interacting with a vertical wall is simulated. The simulated results of water surface elevation are in good agreement with the analytical solution as well as the measured data. The predicted maximum values of the run-up of solitary waves with various relative incident wave heights agree well with the measured results.
文摘An embedded cylinder is a large-diameter cylinder embedded in a soil foundation. The state of failure of such an embedded cylindrical structure shows large deflection instead of slide and overturn of the traditional gravity type of structure placed on a rubble base or foundation base. The critical value of deflection of the embedded cylindrical structure, which is the maximum allowable deflection for stability calculation of the cylinder, is a vital control value. Through investigation on deflection and soil pressures on an embedded cylinder by model experiments, the variations of the angle of rotation θ of a cylinder with effective anti-overturning ratio η and moment MH of thrust are discussed. On the basis of experimental study, the critical value of deflection of the cylindrical structure is proposed in the paper. Meanwhile, the formulas for calculating deflection of cylinders are derived.
文摘The breakwater with top sealed, shallow and wide penetrating box foundations is a new type of structure, applicable to deep water and soft seabed. The relations of horizontal and vertical bearing capacities of the box foundation structure as well as the instability induced failure modes to its dimensions and external loads are discussed through static model tests and wave tests. The mechanical properties of the stability of the box foundation are similar to those of embedded rigid foundations, i.e. the vertical stresses at the bottom of the box are distributed in a linear pattern under the action of vertical loads, and passive and active soil pressures are developed at the front and back sides of the box under the action of horizontal loads; there are two instability induced failure modes of the foundation structure-horizontal slide along the box base and tilting due to insufficient local vertical bearing capacity of the soil beneath the box base. The stability of box foundations can be analyzed by use of the methods applied to analysis of the embedded rigid foundations. To increase the width of the box is the most effective way to improve the stability of box foundations.
基金This project was financially supported by the National Natural Science Foundation of China(Grant No.50279027)
文摘Sliding is one of the principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. Herein, the mass-spring-dashpot model of caisson-base system is used to simulate the vibrating-sliding motion of the caisson under various types of breaking wave impact forces, i.e., single peak impact force, double peak impact force, and shock-damping oscillation impact force. The effects of various breaking wave impacts and the sliding motion on the dynamic response behaviors of caisson breakwaters are investigated and the calculation of relevant system parameters is discussed. It is shown that the dynamic responses of the caisson are significantly different under different types of breaking wave impact forces even when the amplitudes of impact forces are equal. The amplitude of dynamic response of the caisson is lower under single peak impact excitation than that under double peak impact or shock-damping oscillation impact excitation. Though the displacement of the caisson is large due to sliding, the rotation, the sliding force and the overturning moment of the caisson are significantly reduced.
文摘The Eocene Sokor1 Formation is proven oil reservoir rocks in the Termit sub-basin. These sandstone intervals are deeply buried, highly heterogeneous in character and characterized by Low Contrast Low Resistivity (LCLR) log responses. Petrophysical and quantitative well-based rock physics interpretations were integrated for property estimations, fluid and lithology typing in reservoir characterization. Six (6) reservoir sandstone intervals were identified, delineated and correlated across five (5) wells. The estimated petrophysical properties showed that the Eocene Sokor1 sandstones have averagely good reservoir properties with sand_5 interval exhibiting exceptional reservoir properties. <i><span style="font-family:Verdana;">V</span><sub><span style="font-family:Verdana;">p</span></sub><span style="font-family:Verdana;">/V</span><sub><span style="font-family:Verdana;">s</span></sub></i><span style="font-family:Verdana;"> vs. AI and </span><i><span style="font-family:Verdana;">μρ</span></i><span style="font-family:Verdana;"> vs. </span><i><span style="font-family:Verdana;">λρ</span></i><span style="font-family:Verdana;"> elastic cross-plots color coded with reservoir properties (</span><i><span style="font-family:Verdana;">V</span><sub><span style="font-family:Verdana;">sh</span></sub></i><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;"><span style="white-space:nowrap;">Φ</span></span></i><span style="font-family:Verdana;">), show distinct and well separated data clusters signifying hydrocarbon bearing sandstones, brine sandstones and shales/mudstones in the 3D crossplot planes with varying seismic elastic property values in each well thereby, enhancing reservoir characterization and providing information’s about the burial history, reservoir quality and property distribution in the sub-basin. The analys</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">is</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> suggests that, although the reservoir interval has averagely good petrophysical properties in all wells, the seismic elastic crossplots show that these properties are much better distributed in wells 2 and 3 than in wells 4, 5 and 9. Therefore, sand_5 reservoir interval in wells 2 and 3 </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">is</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> likely to be more hydrocarbon bearing and productive than wells 4, 5 and 9 in the sub-basin.</span></span></span>
基金This study is supported by Canadian Hydraulics Center(CHC),R and D Project AMC22000National Natural Science Foundation of China(Grant No.59779004)Foundation of State Key Laboratory of Coastal and Offshore Eng.,Dalian Technology University.
文摘In this paper, the theoretical analysis and experimental studies are employed to investigate the reflection characteristics of partial standing waves caused by wave overtopping and sloping top of structures. Based on the principle of conservation of wave energy flux, the third-order Stokes wave theory is used to formulate the reflection coefficient at wave overtopping; the calculation results are regressed into an applied expression. A series of experiments of wave reflection for a vertical-wall structure with chamfered and overhanging upper sections are carried out to investigate the influence of top slope on wave reflection. The regularity of variation of wave reflection in this case is analysed based on the experimental results.
文摘Wave field around Taipei Port is studied. Using marine radar as a monitoring device, sequences of the wave field images were obtained on an hourly basis. A 3D-FFT was applied to the image sequences leading to the so-called intensity wavenumber-frequency spectrum. Wave field information can then be extracted from these spectra and compared with on-site measurements. It is shown that, when the prevailing winds are weak, estimated wave heights agree miserably with those measured. On the other hand, when the winds are relatively strong, our estimates follow closely with the trends, but are, in general, lower than measured. Possible reasons leading to these discrepancies are discussed.
基金the Guangzhou Education Policy Research Project(ZCYJ20109)2020 Industry University Cooperation Collaborative Education Project(A Letter from the Division of Higher Education[2021]No.3,202002325060,202002325052,202002325050)2021 Teaching Construction Project of Guangzhou Maritime University,and 2019 Guangzhou Educational Science Planning Course(201912027).
文摘This article discusses the problems existing in the teaching of Logistics and the urgency of its curriculum reform,introduces the concept of outcome-based education(OBE)into the teaching process of Logistics,designs the teaching in a reverse direction guided by the results,and implements the teaching design in the form of flipped classroom.A“student-centered”teaching process endows students with stronger autonomy and initiative and encourages them to cooperate with each other.This teaching process provides new ideas and methods for the teaching reform of Logistics as well as the cultivation of excellent logistics talents.
基金supported by the National Natural Science Foundation of China(Grant No.62275210)the National Leading Talent Program,the National Young Talent Program,the Key Research and Development Program of Shaanxi(Grant No.2024SF2-GJHX-25)+5 种基金the Scientific Research Program Funded by the Education Department of Shaanxi Provincial Government(Grant No.24JS016)the Xidian University Specially Funded Project for Interdisciplinary Exploration(Grant No.TZJHF202523)the Fundamental Research Funds for Central Universities(Grant No.YJSJ25014)the Guangdong Provincial General Colleges and Universities Young Innovative Talents Research Project(Grant No.2024KQNCX172)the Shenzhen Science and Technology Program(Grant No.GJHZ20210705141805015)the Key Research Areas Support Science and Technology Project of Shenzhen Institute of Information Technology(Grant No.SZIIT2024KJ056).
文摘Fluorescence microscopy is indispensable in life science research,yet denoising remains challenging due to varied biological samples and imaging conditions.We introduce a wavelet-enhanced transformer based on DnCNN that fuses wavelet preprocessing with a dual-branch transformer-convolutional neural network(CNN)architecture.Wavelet decomposition separates highand low-frequency components for targeted noise reduction;the CNN branch restores local details,whereas the transformer branch captures global context;and an adaptive loss balances quantitative fidelity with perceptual quality.On the fluorescence microscopy denoising benchmark,our method surpasses leading CNNand transformer-based approaches,improving peak signal-to-noise ratio by 2.34%and 0.88%and structural similarity index measure by 0.53%and 1.07%,respectively.This framework offers enhanced generalization and practical gains for fluorescence image denoising.
文摘A numerical model is developed for dynamic analysis of large-cylinder breakwaters embedded in soft soil. In the model, the large cylinder is taken as a rigid body divided into elements and the soft soil is replaced by discrete 3D nonlinear spring-dashpot systems. The numerical model is used to simulate the dynamic response of a large-cylinder breakwater to breaking wave excitation. The effects of the dynamic stress-strain relationship models of the soil, the radius and embedded depth of the cylinder, the nonlinear behaviors of the soil, and the limit strength condition of the soil on the dynamic responses of the large-cylinder structure are investigated with an example given. It is indicated that the above-mentioned factors have significant effects on the dynamic responses of an embedded large cylinder breakwater under breaking wave excitation.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51479035)the Scientific Research Foundation of the Graduate School of Southeast University(Grant No.YBPY1883).
基金the National Natural Science Foundation of China(Grant No.50279027).
文摘Vibrating, sliding and uplift rocking are three elementary motion types of caisson breakwaters. The dynamic model and the numerical simulation method of vibrating-sliding-uplift rocking coupled motion of caisson breakwaters are developed. The histories of displacement, rotation, sliding force and overturning moment of a caisson breakwater under the excitation of breaking wave impact are calculated for the motion models of vibrating, vibrating-sliding, vibrating-uplift rocking and vibrating-sliding-uplift rocking. The effects of various motion models on the stability of caisson breakwaters are investigated. The feasibility of the dynamic design idea that the sliding motion and the uplift rocking motion of caisson breakwaters are allowed under the excitation of breaking wave impact is discussed.
基金This study was supported in part by National Science Foundation(Nos.1832068 and 2101091)and Dr.Kai Yin conducted preliminary ADCIRC modeling study during his visit to FAMUFSU College of Engineering in 2018 before the NSF grant was awarded.
文摘An integrated storm surge modeling and traffic analysis were conducted in this study to assess the effectiveness of hurricane evacuations through a case study of Hurricane Irma.The Category 5 hurricane in 2017 caused a record evacuation with an estimated 6.8 million people relocating statewide in Florida.The Advanced Circulation(ADCIRC)model was applied to simulate storm tides during the hurricane event.Model validations indicated that simulated pressures,winds,and storm surge compared well with observations.Model simulated storm tides and winds were used to estimate the area affected by Hurricane Irma.Results showed that the storm surge and strong wind mainly affected coastal counties in south-west Florida.Only moderate storm tides(maximum about 2.5 m)and maximum wind speed about 115 mph were shown in both model simulations and Federal Emergency Management Agency(FEMA)post-hurricane assessment near the area of hurricane landfall.Storm surges did not rise to the 100-year flood elevation level.The maximum wind was much below the design wind speed of 150–170 mph(Category 5)as defined in Florida Building Code(FBC)for south Florida coastal areas.Compared with the total population of about 2.25 million in the six coastal counties affected by storm surge and Category 1–3 wind,the statewide evacuation of approximately 6.8 million people was found to be an over-evacuation due mainly to the uncertainty of hurricane path,which shifted from south-east to south-west Florida.The uncertainty of hurricane tracks made it difficult to predict the appropriate storm surge inundation zone for evacuation.Traffic data were used to analyze the evacuation traffic patterns.In south-east Florida,evacuation traffic started 4 days before the hurricane’s arrival.However,the hurricane path shifted and eventually landed in south-west Florida,which caused a high level of evacuation traffic in south-west Florida.Over-evacuation caused Evacuation Traffic Index(ETI)to increase to 200%above normal conditions in some sections of highways,which reduced the effectiveness of evacuation.Results from this study show that evacuation efficiency can be improved in the future by more accurate hurricane forecasting,better public awareness of real-time storm surge and wind as well as integrated storm surge and evacuation modeling for quick response to the uncertainty of hurricane forecasting.
文摘Beaches play a pivotal role in supporting the socio-economic sector,particularly within the’Sun,Sea,and Sand’(3S)tourism model.Valued for their ecosystem services,these coastal landforms are among the most dynamic and vulnerable environments,facing significant pressure from various climate challenges,which is further intensified by extensive anthropic exploitation.Their sustainable use is intrinsically linked to balancing the 3Ps:Planet,People,and Profit.To address the need for protection and sustainable utilization of coastal areas,the European Union has introduced the Protocol on Integrated Coastal Zone Management(ICZM)in the Mediterranean,specifically recommending in Article 8(2)the establishment of a setback buffer zone where permanent constructions are prohibited.This paper explores the application of risk mapping in the context of coastal setback policies,focusing on their effectiveness in managing beach retreat and adapting to climate change,particularly rising sea levels.The study examines selected beach areas in Peloponnese,Greece,influenced by various socio-economic factors.Through this analysis,the paper aims to contribute to the discourse on coastal management strategies that balance environmental sustainability with socio-economic benefits.
基金the National Natural Science Foundation of China (Grant No. 19572035).
文摘Wave propagation problems in orthotropic media are studied jointly by analytical and experimental methods in this paper. Dynamic orthotropic photoelasticity, which studies experimentally the dynamic behavior of orthotropic materials on a macroscopic scale by employing orthotropic birefringent materials, is established. A dynamic stress-optic law for orthotropic birefringent materials is postulated and practical methods of calibrating dynamic mechanical constants and dynamic stress-fringe values are proposed. Meanwhile, time domain boundary element method (BEM) for wave propagation in orthotropic media, is also presented based on the theory of elastodynamics. A scheme of stress calculations that is necessary for strength analysis is established. The paper stresses on the applications in wavepropagation problems in orthotropic media by demonstrating three examples. The semi-infinite orthotropic plates with and without a circular hole modeled by a unidirectional fiber-reinforced composite under impact
