The present investigation inspects the unsteady,incompressible MHD-induced flow of a ternary hybrid nanofluid made of SiO_(2)(silicon dioxide),ZnO(zinc oxide),and MWCNT(multi-walled carbon nanotubes)suspended in a wat...The present investigation inspects the unsteady,incompressible MHD-induced flow of a ternary hybrid nanofluid made of SiO_(2)(silicon dioxide),ZnO(zinc oxide),and MWCNT(multi-walled carbon nanotubes)suspended in a water-ethylene glycol base fluid between two perforated squeezing Riga plates.This problem is important because it helps us understand the complicated connections between magnetic fields,nanofluid dynamics,and heat transport,all of which are critical for designing thermal management systems.These findings are especially useful for improving the design of innovative cooling technologies in electronics,energy systems,and healthcare applications.No prior study has been done on the theoretical study of the flow of ternary nanofluid(SiO_(2)+ZnO+MWCNT/Water−EthylGl ycol,(60∶40))past a pierced squeezed Riga plates using the boundary value problem solver 4th-order collocation(BVP4C)numerical approach to date.So,the current work has been carried out to fill this gap,and the core purpose of this study is to explore the aspects that enhance the heat transfer of base fluids(H_(2)O/EG)suspended with three nanomaterials SiO_(2),ZnO,and MWCNT.The Riga plates introduce electromagnetic forcing through an embedded array of magnets and electrodes,generating Lorentz forces to regulate the flow.The squeezing effect introduces dynamic boundary movement,which enhances mixing;however,permeability,due to porosity,replicates the true material limits.Similarity transformations of the Navier-Stokes and energy equations result in a highly nonlinear set of ordinary differential equations that govern momentum and thermal energy transport.The subsequent boundary value problem is solved utilizing the BVP4C numerical approach.The study observes the impact of magnetic parameters,squeezing velocity,solid volume percentages of the three nanoparticles,and porous medium factors on velocity and temperature fields.Results show that magnetic fields reduce the velocity profile by 6.75%due to increased squeezing and medium effects.Tri-hybrid nanofluids notice a 9%rise in temperature with higher thermal radiation.展开更多
We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)proc...We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.展开更多
Rubble mound breakwaters, a prevalent type of sloping breakwater structure, are extensively employed in port and coastal infrastructure projects. Under soft soil foundation conditions, the process of squeezing silt by...Rubble mound breakwaters, a prevalent type of sloping breakwater structure, are extensively employed in port and coastal infrastructure projects. Under soft soil foundation conditions, the process of squeezing silt by riprap is implemented to enhance bearing capacity through soft soil replacement and compaction. However, predicting the depth law of squeezing silt by riprap and understanding its mechanism remain significant engineering design challenges.This study employs particle flow code(PFC) based on the discrete element method to simulate the squeezing silt process by riprap, examining variations in depth law under different geological conditions and its mechanical characteristics.Through calibration of the PFC model's meso-parameters via macro-experiments, the study analyzes the effects of riprap size, drop height, and soft soil properties on the depth law of squeezing silt. Findings demonstrate that riprap drop height and soft soil thickness substantially influence the depth, while appropriate calibration of meso-parameters enhances simulation accuracy. This research contributes theoretical and practical guidance for optimizing rubble mound breakwater design, understanding squeezing silt mechanisms, construction practices, and riprap quantity estimation.展开更多
Squeezing phenomena can lead to severe loads in deep tunnels,especially in the presence of a low ratio of surrounding rock strength to overburden pressure.For this reason,it is highly imperative to analyze and identif...Squeezing phenomena can lead to severe loads in deep tunnels,especially in the presence of a low ratio of surrounding rock strength to overburden pressure.For this reason,it is highly imperative to analyze and identify a suitable methodology to estimate the squeezing potential and select a proper support system of rock mass.This study aims to reveal the causes of failure of Tishreen tunnel in the west of Syria and develop remediation measures accordingly so as to bring the tunnel back into service.The tunnel in question was subjected to successive failures such as buckling and spalling of side walls,floor heave,and extremely large convergence reaching the failure state of the tunnel lining.In this study,an effective way was demonstrated to evaluate the squeezing potential of the tunnel lining and appropriate modeling of the long-term response of a tunnel excavated in weak rock.Specifically,the causes of failure of Tishreen tunnel were first evaluated by empirical approaches.Then,a numerical model was developed using a timedependent constitutive model to investigate the time-dependent response of the tunnel lining.On this basis,this study proposed an effective reinforcement schemes including steel ribs,grout injection,ground anchors,and new lining of reinforced concrete.The results show that the Burger viscoplastic model simulates effectively the resulting deformation and creep behavior of squeezing ground.It is also observed that using a combined heavy support system can provide efficient control over squeezing deformation and maintain the serviceability of the tunnel under study.展开更多
This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates.One plate remains stationary,while the other moves downward at a squeezing veloci...This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates.One plate remains stationary,while the other moves downward at a squeezing velocity.The space between these plates contains a Darcy-Forchheimer porous medium.A mixture of water-based fluid with gold(Au)and silicon dioxide(Si O2)nanoparticles is formulated.In contrast to the conventional Fourier's heat flux equation,this study employs the Cattaneo-Christov heat flux equation.A uniform magnetic field is applied perpendicular to the flow direction,invoking magnetohydrodynamic(MHD)effects.Further,the model accounts for Joule heating,which is the heat generated when an electric current passes through the fluid.The problem is solved via NDSolve in MATHEMATICA.Numerical and statistical analyses are conducted to provide insights into the behavior of the nanomaterials between the parallel plates with respect to the flow,energy transport,and skin friction.The findings of this study have potential applications in enhancing cooling systems and optimizing thermal management strategies.It is observed that the squeezing motion generates additional pressure gradients within the fluid,which enhances the flow rate but reduces the frictional drag.Consequently,the fluid is pushed more vigorously between the plates,increasing the flow velocity.As the fluid experiences higher flow rates due to the increased squeezing effect,it spends less time in the region between the plates.The thermal relaxation,however,abruptly changes the temperature,leading to a decrease in the temperature fluctuations.展开更多
The Haidong Water Conveyance Tunnel(HWCT),a notable engineering feat located within Dali City,Yunnan Province,China,represents an ultra-long water conveyance tunnel situated in a region characterized by medium in-situ...The Haidong Water Conveyance Tunnel(HWCT),a notable engineering feat located within Dali City,Yunnan Province,China,represents an ultra-long water conveyance tunnel situated in a region characterized by medium in-situ stress conditions.As part of the Central Yunnan Water Diversion Project,this tunnel was specifically engineered for soft-rock environments.The excavation of such tunnels presents significant challenges due to rock mass deformation,commonly referred to as squeezing ground behavior.These challenges are exacerbated when navigating through diverse geological and geomorphological units,particularly in areas with complex geological conditions.To address these issues,an innovative active support system utilizing prestressed anchor cables was developed for the HWCT.This study provides a comprehensive analysis and comparison of rock mass behavior between two support systems:a conventional passive system employing steel arches and the proposed active system using prestressed anchor cables.The numerical modeling was performed using FLAC3D software to simulate various scenarios,while an extensive monitoring program was implemented in several representative tunnel sections to measure key parameters including rock mass stresses,displacements,internal forces in steel arches,and axial forces in anchor cables.The results from both the numerical simulations and field observations were systematically compared.The analyses demonstrated the superior performance of the active support system using prestressed anchor cables in the HWCT,significantly enhancing overall rock mass stability and effectively mitigating large deformation issues throughout the tunnel.展开更多
基于计算机视觉的航拍绝缘子缺陷检测方法被广泛应用于电力巡检。针对绝缘子缺陷易受背景复杂、目标尺度较小等因素的影响而导致漏检、误检的问题,提出了一种旨在提高绝缘子缺陷检测精度的绝缘子缺陷检测模型YOLO-insulator。首先,引入...基于计算机视觉的航拍绝缘子缺陷检测方法被广泛应用于电力巡检。针对绝缘子缺陷易受背景复杂、目标尺度较小等因素的影响而导致漏检、误检的问题,提出了一种旨在提高绝缘子缺陷检测精度的绝缘子缺陷检测模型YOLO-insulator。首先,引入基于通道混洗的重参数化卷积(reparameterized convolution based on channel shuffle-one-shot aggregation, RCS-OSA)替换传统的二维卷积C2f,以增强网络的特征提取能力;其次,在颈部网络使用RCS-OSA模块替换部分的C2f卷积,同时引入挤压激励网络(squeeze and excitation network,SENet),以增强模型对通道间关系的捕捉和整体特征的表达能力;最后,针对多种缺陷区域小导致难以检测的问题,提出小目标检测层方法,该层包含更多的缺陷细节信息,有利于缺陷的检测。在自制绝缘子数据集上进行实验验证的结果表明,相对于基线YOLOv8n,YOLO-insulator模型在查准率、召回率、平均精度均值上都实现了提升,有效提高了模型的综合性能。展开更多
针对火焰检测过程中存在小目标难以检测的问题,提出了一种改进的YOLOv8n模型。首先,在双分支跨阶段局部特征融合(cross stage partial 2 with feature fusion,C2f)模块中加入动态蛇形卷积,有助于提取多尺度特征、增强特征表示。接着,将G...针对火焰检测过程中存在小目标难以检测的问题,提出了一种改进的YOLOv8n模型。首先,在双分支跨阶段局部特征融合(cross stage partial 2 with feature fusion,C2f)模块中加入动态蛇形卷积,有助于提取多尺度特征、增强特征表示。接着,将GhostnetV2引入到颈部网络中,不仅减少了模型的参数量,还提升了整体的检测精度和速度。然后,添加微小目标检测头以便更好地进行多尺度小目标的检测,基于局部和全局的挤压激励(squeeze and excitation,SE)注意力机制确保每一层的特征都得到充分优化,特别是小目标的细微特征。最后,基于最小点距离的交并比损失函数提高算法的收敛速度和定位精度。实验结果显示,改进YOLOv8n模型的P、R、FPS、mAP@0.5和mAP@0.5∶0.95指标平均值比YOLOv8n模型分别提高了3.34%、3.62%、14帧/s、3.01%和3.41%,表明模型拥有较好的小目标火焰检测能力。研究结果可为预防火灾等安全事故提供理论依据和决策支撑。展开更多
基金funded by King Saud University,Riyadh,Saudi Arabia,through the Ongo-ing Research Funding program—Research Chairs(ORF-RC-2025-0127)funded via Princess Nourah bint Abdulrahman University Researchers Supporting Project number(PNURSP2025R443).
文摘The present investigation inspects the unsteady,incompressible MHD-induced flow of a ternary hybrid nanofluid made of SiO_(2)(silicon dioxide),ZnO(zinc oxide),and MWCNT(multi-walled carbon nanotubes)suspended in a water-ethylene glycol base fluid between two perforated squeezing Riga plates.This problem is important because it helps us understand the complicated connections between magnetic fields,nanofluid dynamics,and heat transport,all of which are critical for designing thermal management systems.These findings are especially useful for improving the design of innovative cooling technologies in electronics,energy systems,and healthcare applications.No prior study has been done on the theoretical study of the flow of ternary nanofluid(SiO_(2)+ZnO+MWCNT/Water−EthylGl ycol,(60∶40))past a pierced squeezed Riga plates using the boundary value problem solver 4th-order collocation(BVP4C)numerical approach to date.So,the current work has been carried out to fill this gap,and the core purpose of this study is to explore the aspects that enhance the heat transfer of base fluids(H_(2)O/EG)suspended with three nanomaterials SiO_(2),ZnO,and MWCNT.The Riga plates introduce electromagnetic forcing through an embedded array of magnets and electrodes,generating Lorentz forces to regulate the flow.The squeezing effect introduces dynamic boundary movement,which enhances mixing;however,permeability,due to porosity,replicates the true material limits.Similarity transformations of the Navier-Stokes and energy equations result in a highly nonlinear set of ordinary differential equations that govern momentum and thermal energy transport.The subsequent boundary value problem is solved utilizing the BVP4C numerical approach.The study observes the impact of magnetic parameters,squeezing velocity,solid volume percentages of the three nanoparticles,and porous medium factors on velocity and temperature fields.Results show that magnetic fields reduce the velocity profile by 6.75%due to increased squeezing and medium effects.Tri-hybrid nanofluids notice a 9%rise in temperature with higher thermal radiation.
基金Project supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202400624)the Natural Science Foundation of Chongqing CSTC(Grant No.CSTB2022NSCQBHX0020)+3 种基金the China Electronics Technology Group Corporation 44th Research Institute(Grant No.6310001-2)the Project Grant“Noninvasive Sensing Measurement based on Terahertz Technology”from Province and MOE Collaborative Innovation Centre for New Generation Information Networking and Terminalsthe Key Research Program of CQUPT on Interdisciplinary and Emerging Field(A2018-01)the Venture&Innovation Support program for Chongqing Overseas Returnees Year 2022。
文摘We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.
基金financially supported by the Fundamental Research Funds for the Central Universities (Grant Nos.B200202087 and B200204032)the National Natural Science Foundation of China (Grant No.51609071)。
文摘Rubble mound breakwaters, a prevalent type of sloping breakwater structure, are extensively employed in port and coastal infrastructure projects. Under soft soil foundation conditions, the process of squeezing silt by riprap is implemented to enhance bearing capacity through soft soil replacement and compaction. However, predicting the depth law of squeezing silt by riprap and understanding its mechanism remain significant engineering design challenges.This study employs particle flow code(PFC) based on the discrete element method to simulate the squeezing silt process by riprap, examining variations in depth law under different geological conditions and its mechanical characteristics.Through calibration of the PFC model's meso-parameters via macro-experiments, the study analyzes the effects of riprap size, drop height, and soft soil properties on the depth law of squeezing silt. Findings demonstrate that riprap drop height and soft soil thickness substantially influence the depth, while appropriate calibration of meso-parameters enhances simulation accuracy. This research contributes theoretical and practical guidance for optimizing rubble mound breakwater design, understanding squeezing silt mechanisms, construction practices, and riprap quantity estimation.
文摘Squeezing phenomena can lead to severe loads in deep tunnels,especially in the presence of a low ratio of surrounding rock strength to overburden pressure.For this reason,it is highly imperative to analyze and identify a suitable methodology to estimate the squeezing potential and select a proper support system of rock mass.This study aims to reveal the causes of failure of Tishreen tunnel in the west of Syria and develop remediation measures accordingly so as to bring the tunnel back into service.The tunnel in question was subjected to successive failures such as buckling and spalling of side walls,floor heave,and extremely large convergence reaching the failure state of the tunnel lining.In this study,an effective way was demonstrated to evaluate the squeezing potential of the tunnel lining and appropriate modeling of the long-term response of a tunnel excavated in weak rock.Specifically,the causes of failure of Tishreen tunnel were first evaluated by empirical approaches.Then,a numerical model was developed using a timedependent constitutive model to investigate the time-dependent response of the tunnel lining.On this basis,this study proposed an effective reinforcement schemes including steel ribs,grout injection,ground anchors,and new lining of reinforced concrete.The results show that the Burger viscoplastic model simulates effectively the resulting deformation and creep behavior of squeezing ground.It is also observed that using a combined heavy support system can provide efficient control over squeezing deformation and maintain the serviceability of the tunnel under study.
文摘This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates.One plate remains stationary,while the other moves downward at a squeezing velocity.The space between these plates contains a Darcy-Forchheimer porous medium.A mixture of water-based fluid with gold(Au)and silicon dioxide(Si O2)nanoparticles is formulated.In contrast to the conventional Fourier's heat flux equation,this study employs the Cattaneo-Christov heat flux equation.A uniform magnetic field is applied perpendicular to the flow direction,invoking magnetohydrodynamic(MHD)effects.Further,the model accounts for Joule heating,which is the heat generated when an electric current passes through the fluid.The problem is solved via NDSolve in MATHEMATICA.Numerical and statistical analyses are conducted to provide insights into the behavior of the nanomaterials between the parallel plates with respect to the flow,energy transport,and skin friction.The findings of this study have potential applications in enhancing cooling systems and optimizing thermal management strategies.It is observed that the squeezing motion generates additional pressure gradients within the fluid,which enhances the flow rate but reduces the frictional drag.Consequently,the fluid is pushed more vigorously between the plates,increasing the flow velocity.As the fluid experiences higher flow rates due to the increased squeezing effect,it spends less time in the region between the plates.The thermal relaxation,however,abruptly changes the temperature,leading to a decrease in the temperature fluctuations.
基金support provided by the Technology Development Service Project Funds of China,Railway 5th Bureau Group Fifth Engineering Co.,Ltd and Yunnan Institute of Water&Hydropower Engineering Investigation,Design and Research(Grant No.20230525)the Major Science and Technology Special Plan of Yunnan Province Science and Technology Department(Grant No.202002AF080003)the Fundamental Research Funds for the Central Universities(Grant No.2022YJSSB04).
文摘The Haidong Water Conveyance Tunnel(HWCT),a notable engineering feat located within Dali City,Yunnan Province,China,represents an ultra-long water conveyance tunnel situated in a region characterized by medium in-situ stress conditions.As part of the Central Yunnan Water Diversion Project,this tunnel was specifically engineered for soft-rock environments.The excavation of such tunnels presents significant challenges due to rock mass deformation,commonly referred to as squeezing ground behavior.These challenges are exacerbated when navigating through diverse geological and geomorphological units,particularly in areas with complex geological conditions.To address these issues,an innovative active support system utilizing prestressed anchor cables was developed for the HWCT.This study provides a comprehensive analysis and comparison of rock mass behavior between two support systems:a conventional passive system employing steel arches and the proposed active system using prestressed anchor cables.The numerical modeling was performed using FLAC3D software to simulate various scenarios,while an extensive monitoring program was implemented in several representative tunnel sections to measure key parameters including rock mass stresses,displacements,internal forces in steel arches,and axial forces in anchor cables.The results from both the numerical simulations and field observations were systematically compared.The analyses demonstrated the superior performance of the active support system using prestressed anchor cables in the HWCT,significantly enhancing overall rock mass stability and effectively mitigating large deformation issues throughout the tunnel.
文摘基于计算机视觉的航拍绝缘子缺陷检测方法被广泛应用于电力巡检。针对绝缘子缺陷易受背景复杂、目标尺度较小等因素的影响而导致漏检、误检的问题,提出了一种旨在提高绝缘子缺陷检测精度的绝缘子缺陷检测模型YOLO-insulator。首先,引入基于通道混洗的重参数化卷积(reparameterized convolution based on channel shuffle-one-shot aggregation, RCS-OSA)替换传统的二维卷积C2f,以增强网络的特征提取能力;其次,在颈部网络使用RCS-OSA模块替换部分的C2f卷积,同时引入挤压激励网络(squeeze and excitation network,SENet),以增强模型对通道间关系的捕捉和整体特征的表达能力;最后,针对多种缺陷区域小导致难以检测的问题,提出小目标检测层方法,该层包含更多的缺陷细节信息,有利于缺陷的检测。在自制绝缘子数据集上进行实验验证的结果表明,相对于基线YOLOv8n,YOLO-insulator模型在查准率、召回率、平均精度均值上都实现了提升,有效提高了模型的综合性能。
文摘针对火焰检测过程中存在小目标难以检测的问题,提出了一种改进的YOLOv8n模型。首先,在双分支跨阶段局部特征融合(cross stage partial 2 with feature fusion,C2f)模块中加入动态蛇形卷积,有助于提取多尺度特征、增强特征表示。接着,将GhostnetV2引入到颈部网络中,不仅减少了模型的参数量,还提升了整体的检测精度和速度。然后,添加微小目标检测头以便更好地进行多尺度小目标的检测,基于局部和全局的挤压激励(squeeze and excitation,SE)注意力机制确保每一层的特征都得到充分优化,特别是小目标的细微特征。最后,基于最小点距离的交并比损失函数提高算法的收敛速度和定位精度。实验结果显示,改进YOLOv8n模型的P、R、FPS、mAP@0.5和mAP@0.5∶0.95指标平均值比YOLOv8n模型分别提高了3.34%、3.62%、14帧/s、3.01%和3.41%,表明模型拥有较好的小目标火焰检测能力。研究结果可为预防火灾等安全事故提供理论依据和决策支撑。
