Real-time detection of unhealthy fish remains a significant challenge in intensive recirculating aquaculture.Early recognition of unhealthy fish and the implementation of appropriate treatment measures are crucial for...Real-time detection of unhealthy fish remains a significant challenge in intensive recirculating aquaculture.Early recognition of unhealthy fish and the implementation of appropriate treatment measures are crucial for preventing the spread of diseases and minimizing economic losses.To address this issue,an improved algorithm based on the You Only Look Once v5s(YOLOv5s)lightweight model has been proposed.This enhanced model incorporates a faster lightweight structure and a new Convolutional Block Attention Module(CBAM)to achieve high recognition accuracy.Furthermore,the model introduces theα-SIoU loss function,which combines theα-Intersection over Union(α-IoU)and Shape Intersection over Union(SIoU)loss functions,thereby improving the accuracy of bounding box regression and object recognition.The average precision of the improved model reaches 94.2%for detecting unhealthy fish,representing increases of 11.3%,9.9%,9.7%,2.5%,and 2.1%compared to YOLOv3-tiny,YOLOv4,YOLOv5s,GhostNet-YOLOv5,and YOLOv7,respectively.Additionally,the improved model positively impacts hardware efficiency,reducing requirements for memory size by 59.0%,67.0%,63.0%,44.7%,and 55.6%in comparison to the five models mentioned above.The experimental results underscore the effectiveness of these approaches in addressing the challenges associated with fish health detection,and highlighting their significant practical implications and broad application prospects.展开更多
The aim of this paper is to investigate the role of lightweight structures and connections in the DfD(design for disassembly)framework.The construction sector is facing pressure to reduce its environmental impact,whic...The aim of this paper is to investigate the role of lightweight structures and connections in the DfD(design for disassembly)framework.The construction sector is facing pressure to reduce its environmental impact,which has led to heightened interest in DfD as a strategy for transitioning from a linear“Cradle to Grave”economic model to a circular“Cradle to Cradle”model.At the social level,DfD’s technological and spatial flexibility provides opportunities for self-build and self-maintenance processes,which can decrease land consumption and reduce costs for both owners and tenants.In this context,lightweight structures and connections are crucial for enabling these processes.The methodology used for analysis involves breaking down three technological elements chosen from three different projects to evaluate ease of disassembly,flexibility,potential for reuse,and recyclability.As a result,this paper aims to promote the development of an abacus of existing technological solutions,to provide designers with a tool that can help them pursue DfD strategies.展开更多
Continuously rising demands of legislators require a significant reduction of CO2-emission and thus fuel consumption across all vehicle classes. In this context, lightweight construction materials and designs become a...Continuously rising demands of legislators require a significant reduction of CO2-emission and thus fuel consumption across all vehicle classes. In this context, lightweight construction materials and designs become a single most important factor. The main engineering challenge is to precisely adapt the material and component properties to the specific load situation. However, metallic car body structures using “Tailored blanks” or “Patchwork structures” meet these requirements only insufficiently, especially for complex load situations (like crash). An innovative approach has been developed to use laser beams to locally strengthen steel crash structures used in vehicle bodies. The method tailors the workpiece hardness and thus strength at selected locations to adjust the material properties for the expected load distribution. As a result, free designable 3D-strengthening-patterns surrounded by softer base metal zones can be realized by high power laser beams at high processing speed. The paper gives an overview of the realizable process window for different laser treatment modes using current high brilliant laser types. Furthermore, an efficient calculation model for determining the laser track properties (depth/width and flow curve) is shown. Based on that information, simultaneous FE modelling can be efficiently performed. Chassis components are both statically and cyclically loaded. Especially for these components, a modulation of the fatigue behavior by laser-treated structures has been investigated. Simulation and experimental results of optimized crash and deep drawing components with up to 55% improved level of performance are also illustrated.展开更多
Most of recent research on carbody lightweighting has focused on substitute material and new processing technologies rather than structures. However, new materials and processing techniques inevitably lead to higher c...Most of recent research on carbody lightweighting has focused on substitute material and new processing technologies rather than structures. However, new materials and processing techniques inevitably lead to higher costs. Also, material substitution and processing lightweighting have to be realized through body structural profiles and locations. In the huge conventional workload of lightweight optimization, model modifications involve heavy manual work, and it always leads to a large number of iteration calculations. As a new technique in carbody lightweighting, the implicit parameterization is used to optimize the carbody structure to improve the materials utilization rate in this paper. The implicit parameterized structural modeling enables the use of automatic modification and rapid multidisciplinary design optimization （MDO） in carbody structure, which is impossible in the traditional structure finite element method （FEM） without parameterization. The structural SFE parameterized model is built in accordance with the car structural FE model in concept development stage, and it is validated by some structural performance data. The validated SFE structural parameterized model can be used to generate rapidly and automatically FE model and evaluate different design variables group in the integrated MDO loop. The lightweighting result of body-in-white （BIW） after the optimization rounds reveals that the implicit parameterized model makes automatic MDO feasible and can significantly improve the computational efficiency of carbody structural lightweighting. This paper proposes the integrated method of implicit parameterized model and MDO, which has the obvious practical advantage and industrial significance in the carbody structural lightweighting design.展开更多
The twenty-first century is one of the most complex in the history of humanity,mainly due to the ecological crisis it is going through.The construction sector generates about 40%of CO2 emissions into the environment;t...The twenty-first century is one of the most complex in the history of humanity,mainly due to the ecological crisis it is going through.The construction sector generates about 40%of CO2 emissions into the environment;the foregoing should motivate this sector to seek new alternatives to develop new building practices.Taking these current needs into account,this document classifies and presents a multidisciplinary solution that integrates biology,engineering and architecture to develop a new and innovative lightweight timber structure;it divides with a main structure made of timber and an innovative joint system made of bio-polymers connecting all the panels.Through the study of diatoms,it was able to analyze the bio-morphology of the structure,joints and in particular the geometry since they were the inspiration for the design of this structure that presents an innovative and novel design of structural optimization.Through parametric design and digital fabrication,it was able to create a complex geometry that obtains excellent structural behavior.This research discusses and explores how materials,geometry led to the optimization of a structure and how new structures can arise,thanks to biology new solutions can be obtained that are completely sustainable,being a clear example of how to combat the effects of the climate change and in a precise way it highlights the advantages of the bio-design in the architectural design.展开更多
In order to meet the objective requirements of the safety and comfort of the modern lightweight timber floors,and strengthen the research on the coupling performance of the lightweight timber floors vibration characte...In order to meet the objective requirements of the safety and comfort of the modern lightweight timber floors,and strengthen the research on the coupling performance of the lightweight timber floors vibration characteristics and the building comfort,this article discusses the floor of a two-story prefabricated lightweight timber building demonstration house.In this paper,the floor structure of a two-story light-weight wooden house has been carried out on structural calculation modal and experimental modal,static uniform load and concentrated load deflection value testing.The evaluation of the deflection value of the floor structure,the mode shape,the coupling of the fundamental frequency mode parameters,and the vibration comfort were also studied.The results show that the fundamental frequency simulation value,one-way modal test value and two-way modal test value of the floor structure all meet the requirements of BS-6472(BS6472-1:2008).That is,the floor structure is not lower than 8 Hz design requirements,and meets the frequency of BS-6472(BS6472-1:2008).The weighted root mean square acceleration is lower than the requirement of 0.45 m/s^(2);the first three natural frequencies of the floor structure calculated by the finite element simulation are 16.413,31.847 and 48.921 Hz,and the fundamental frequency mode is the bending vibration in the length and width directions.The second order is the bending mode in the length direction,and the third order is the bending mode in the width direction.The fundamental frequency of the two-way modal test of the floor structure is the first-order bending mode in the X direction;and the second-order natural frequency is the second-order bending vibration shape in the X direction.when the uniform load is mainly the weight of floor own,the simulated maximum deflection value is 1.0658 mm;the simulation is performed according to the standard value of 0.566 kN/m for the uniform load of the floor design,and the simulation is the largest.The maximum deflection value of the simulated floor is 1.47383 mm at its midpoint,which meets the requirements of National Building Code of Canada-2015(NBCC).The maximum deflection limit of the light wood structure floor system is lower than 3 m and the maximum deflection limit is 2 mm;the six deflection value test lines simulated under a concentrated load of 1 kN all present a parabolic distribution and are symmetrical.The above results has engineering application value for promoting the research on the vibration characteristics of the fabricated lightweight timber floors structure and its optimization design.展开更多
Damage evolution characterization and performance evaluation under realistic conditions are essential to ensure reliable operation of critical safety components.However,previous studies focus on the surface detection ...Damage evolution characterization and performance evaluation under realistic conditions are essential to ensure reliable operation of critical safety components.However,previous studies focus on the surface detection because of very limited penetration capacity of nondestructive testing facilities.Here,we review the recent progress of material damage mechanism by various in situ testing rigs that are compat-ible with laboratory and synchrotron radiation X-ray facilities.Then,taking metallic alloys and composites as model materials,we demonstrate the unique advantages of in situ X-ray three-dimensional tomography in unveiling complex failure mechanisms,quantifying crack growth driving forces and crack closure phenomena,and elucidating the strengthening/degrading effects from microstructure and environment on structural material degradation.Finally,we also discuss the ongoing direction of in situ multi-scale visualization and characterization with the development of advanced high-energy X-ray facilities,the improvement of in situ devices and sample environments,the demand of high-throughput tests,and the processing and application of massive test data.展开更多
基金supported by The Agricultural Science and Technology Independent Innovation Fund Project of Jiangsu Province(CX(22)3111)the National Natural Science Foundation of China Project(62173162)partly by the Changzhou Science and Technology Support Project(CE20225016).
文摘Real-time detection of unhealthy fish remains a significant challenge in intensive recirculating aquaculture.Early recognition of unhealthy fish and the implementation of appropriate treatment measures are crucial for preventing the spread of diseases and minimizing economic losses.To address this issue,an improved algorithm based on the You Only Look Once v5s(YOLOv5s)lightweight model has been proposed.This enhanced model incorporates a faster lightweight structure and a new Convolutional Block Attention Module(CBAM)to achieve high recognition accuracy.Furthermore,the model introduces theα-SIoU loss function,which combines theα-Intersection over Union(α-IoU)and Shape Intersection over Union(SIoU)loss functions,thereby improving the accuracy of bounding box regression and object recognition.The average precision of the improved model reaches 94.2%for detecting unhealthy fish,representing increases of 11.3%,9.9%,9.7%,2.5%,and 2.1%compared to YOLOv3-tiny,YOLOv4,YOLOv5s,GhostNet-YOLOv5,and YOLOv7,respectively.Additionally,the improved model positively impacts hardware efficiency,reducing requirements for memory size by 59.0%,67.0%,63.0%,44.7%,and 55.6%in comparison to the five models mentioned above.The experimental results underscore the effectiveness of these approaches in addressing the challenges associated with fish health detection,and highlighting their significant practical implications and broad application prospects.
文摘The aim of this paper is to investigate the role of lightweight structures and connections in the DfD(design for disassembly)framework.The construction sector is facing pressure to reduce its environmental impact,which has led to heightened interest in DfD as a strategy for transitioning from a linear“Cradle to Grave”economic model to a circular“Cradle to Cradle”model.At the social level,DfD’s technological and spatial flexibility provides opportunities for self-build and self-maintenance processes,which can decrease land consumption and reduce costs for both owners and tenants.In this context,lightweight structures and connections are crucial for enabling these processes.The methodology used for analysis involves breaking down three technological elements chosen from three different projects to evaluate ease of disassembly,flexibility,potential for reuse,and recyclability.As a result,this paper aims to promote the development of an abacus of existing technological solutions,to provide designers with a tool that can help them pursue DfD strategies.
文摘Continuously rising demands of legislators require a significant reduction of CO2-emission and thus fuel consumption across all vehicle classes. In this context, lightweight construction materials and designs become a single most important factor. The main engineering challenge is to precisely adapt the material and component properties to the specific load situation. However, metallic car body structures using “Tailored blanks” or “Patchwork structures” meet these requirements only insufficiently, especially for complex load situations (like crash). An innovative approach has been developed to use laser beams to locally strengthen steel crash structures used in vehicle bodies. The method tailors the workpiece hardness and thus strength at selected locations to adjust the material properties for the expected load distribution. As a result, free designable 3D-strengthening-patterns surrounded by softer base metal zones can be realized by high power laser beams at high processing speed. The paper gives an overview of the realizable process window for different laser treatment modes using current high brilliant laser types. Furthermore, an efficient calculation model for determining the laser track properties (depth/width and flow curve) is shown. Based on that information, simultaneous FE modelling can be efficiently performed. Chassis components are both statically and cyclically loaded. Especially for these components, a modulation of the fatigue behavior by laser-treated structures has been investigated. Simulation and experimental results of optimized crash and deep drawing components with up to 55% improved level of performance are also illustrated.
基金Supported by National Natural Science Foundation of China(Grant No.51175214)Scientific and Technological Planning Project of China(Grant No.2011BAG03B02-1)
文摘Most of recent research on carbody lightweighting has focused on substitute material and new processing technologies rather than structures. However, new materials and processing techniques inevitably lead to higher costs. Also, material substitution and processing lightweighting have to be realized through body structural profiles and locations. In the huge conventional workload of lightweight optimization, model modifications involve heavy manual work, and it always leads to a large number of iteration calculations. As a new technique in carbody lightweighting, the implicit parameterization is used to optimize the carbody structure to improve the materials utilization rate in this paper. The implicit parameterized structural modeling enables the use of automatic modification and rapid multidisciplinary design optimization （MDO） in carbody structure, which is impossible in the traditional structure finite element method （FEM） without parameterization. The structural SFE parameterized model is built in accordance with the car structural FE model in concept development stage, and it is validated by some structural performance data. The validated SFE structural parameterized model can be used to generate rapidly and automatically FE model and evaluate different design variables group in the integrated MDO loop. The lightweighting result of body-in-white （BIW） after the optimization rounds reveals that the implicit parameterized model makes automatic MDO feasible and can significantly improve the computational efficiency of carbody structural lightweighting. This paper proposes the integrated method of implicit parameterized model and MDO, which has the obvious practical advantage and industrial significance in the carbody structural lightweighting design.
文摘The twenty-first century is one of the most complex in the history of humanity,mainly due to the ecological crisis it is going through.The construction sector generates about 40%of CO2 emissions into the environment;the foregoing should motivate this sector to seek new alternatives to develop new building practices.Taking these current needs into account,this document classifies and presents a multidisciplinary solution that integrates biology,engineering and architecture to develop a new and innovative lightweight timber structure;it divides with a main structure made of timber and an innovative joint system made of bio-polymers connecting all the panels.Through the study of diatoms,it was able to analyze the bio-morphology of the structure,joints and in particular the geometry since they were the inspiration for the design of this structure that presents an innovative and novel design of structural optimization.Through parametric design and digital fabrication,it was able to create a complex geometry that obtains excellent structural behavior.This research discusses and explores how materials,geometry led to the optimization of a structure and how new structures can arise,thanks to biology new solutions can be obtained that are completely sustainable,being a clear example of how to combat the effects of the climate change and in a precise way it highlights the advantages of the bio-design in the architectural design.
基金funded by Co-Innovation Center of Efficient Processing and Utilization of Forest Resources,Nanjing Forestry University,Nanjing 210037,China.
文摘In order to meet the objective requirements of the safety and comfort of the modern lightweight timber floors,and strengthen the research on the coupling performance of the lightweight timber floors vibration characteristics and the building comfort,this article discusses the floor of a two-story prefabricated lightweight timber building demonstration house.In this paper,the floor structure of a two-story light-weight wooden house has been carried out on structural calculation modal and experimental modal,static uniform load and concentrated load deflection value testing.The evaluation of the deflection value of the floor structure,the mode shape,the coupling of the fundamental frequency mode parameters,and the vibration comfort were also studied.The results show that the fundamental frequency simulation value,one-way modal test value and two-way modal test value of the floor structure all meet the requirements of BS-6472(BS6472-1:2008).That is,the floor structure is not lower than 8 Hz design requirements,and meets the frequency of BS-6472(BS6472-1:2008).The weighted root mean square acceleration is lower than the requirement of 0.45 m/s^(2);the first three natural frequencies of the floor structure calculated by the finite element simulation are 16.413,31.847 and 48.921 Hz,and the fundamental frequency mode is the bending vibration in the length and width directions.The second order is the bending mode in the length direction,and the third order is the bending mode in the width direction.The fundamental frequency of the two-way modal test of the floor structure is the first-order bending mode in the X direction;and the second-order natural frequency is the second-order bending vibration shape in the X direction.when the uniform load is mainly the weight of floor own,the simulated maximum deflection value is 1.0658 mm;the simulation is performed according to the standard value of 0.566 kN/m for the uniform load of the floor design,and the simulation is the largest.The maximum deflection value of the simulated floor is 1.47383 mm at its midpoint,which meets the requirements of National Building Code of Canada-2015(NBCC).The maximum deflection limit of the light wood structure floor system is lower than 3 m and the maximum deflection limit is 2 mm;the six deflection value test lines simulated under a concentrated load of 1 kN all present a parabolic distribution and are symmetrical.The above results has engineering application value for promoting the research on the vibration characteristics of the fabricated lightweight timber floors structure and its optimization design.
基金supported by the National Natural Science Foundation of China(Nos.U2032121,12192212,and 52325407).
文摘Damage evolution characterization and performance evaluation under realistic conditions are essential to ensure reliable operation of critical safety components.However,previous studies focus on the surface detection because of very limited penetration capacity of nondestructive testing facilities.Here,we review the recent progress of material damage mechanism by various in situ testing rigs that are compat-ible with laboratory and synchrotron radiation X-ray facilities.Then,taking metallic alloys and composites as model materials,we demonstrate the unique advantages of in situ X-ray three-dimensional tomography in unveiling complex failure mechanisms,quantifying crack growth driving forces and crack closure phenomena,and elucidating the strengthening/degrading effects from microstructure and environment on structural material degradation.Finally,we also discuss the ongoing direction of in situ multi-scale visualization and characterization with the development of advanced high-energy X-ray facilities,the improvement of in situ devices and sample environments,the demand of high-throughput tests,and the processing and application of massive test data.
