To ensure the safe performance of deep-sea mining vehicles(DSMVs),it is necessary to study the mechanical characteristics of the interaction between the seabed soil and the track plate.The rotation and digging motions...To ensure the safe performance of deep-sea mining vehicles(DSMVs),it is necessary to study the mechanical characteristics of the interaction between the seabed soil and the track plate.The rotation and digging motions of the track plate are important links in the contact between the driving mechanism of the DSMV and seabed soil.In this study,a numerical simulation is conducted using the coupled Eulerian–Lagrangian(CEL)large deformation numerical method to investigate the interaction between the track plate of the DSMV and the seabed soil under two working conditions:rotating condition and digging condition.First,a soil numerical model is established based on the elastoplastic mechanical characterization using the basic physical and mechanical properties of the seabed soil obtained by in situ sampling.Subsequently,the soil disturbance mechanism and the dynamic mechanical response of the track plate under rotating and digging conditions are obtained through the analysis of the sensitivity of the motion parameters,the grouser structure,the layered soil features and the soil heterogeneity.The results indicate that the above parameters remarkably influence the interaction between the DSMV and the seabed soil.Therefore,it is important to consider the rotating and digging motion of the DSMV in practical engineering to develop a detailed optimization design of the track plate.展开更多
Collective behaviors efficiently impart benefits to a diversity of species ranging from bacteria to humans.Fly larvae tend to cluster and form coordinated digging groups under crowded conditions,yet understanding the ...Collective behaviors efficiently impart benefits to a diversity of species ranging from bacteria to humans.Fly larvae tend to cluster and form coordinated digging groups under crowded conditions,yet understanding the rules governing this behavior is in its infancy.We primarily took advantage of the Drosophila model to investigate cooperative foraging behavior.Here,we report that Drosophila-related species and the black soldier fly have evolved a conserved strategy of cluster digging in food foraging.Subsequently,we investigated relative factors,including larval stage,population density,and food stiffness and quality,that affect the cluster digging behavior.Remarkably,oxygen supply through the posterior breathing spiracles is necessary for the organization of digging clusters.More importantly,we theoretically devise a mathematical model to accurately calculate how the cluster digging behavior expands food resources by diving depth,cross-section area,and food volume.We found that cluster digging behavior approximately increases 2.2 fold depth,1.7-fold cross-section area,and 1.9 fold volume than control groups,respectively.Amplification of food sources significantly facilitates survival,larval development,and reproductive success of Drosophila challenged with competition for limited food resources,thereby conferring trophic benefits to fitness in insects.Overall,our findings highlight that the cluster digging behavior is a pivotal behavior for their adaptation to food scarcity,advancing a better understanding of how this cooperative behavior confers fitness benefits in the animal kingdom.展开更多
In view of the problems of easy damage and high digging resistance in the process of green onion harvesting,a mechanical model of digging green onions was established by taking the moment of digging and drawing green ...In view of the problems of easy damage and high digging resistance in the process of green onion harvesting,a mechanical model of digging green onions was established by taking the moment of digging and drawing green onions as the research object,and the main factors affecting the digging and harvesting effect were determined as the angle of digging,the dip angle of clamping carrier and the length of shovel.Thus,a complex simulation model of soil-green onion-digging mechanism system reflecting the state of harvesting was established,and the model was verified by testing soil compactness.The simulation tests were carried out by means of the complex simulation model of soil-green onion-digging mechanism system,making it clear that digging angle and the length of shovel have a extremely significant impact on the digging resistance,and the dip angle of the clamping carrier had a significant impact on the digging resistance.Through target optimization,the optimal combination of digging parameters was obtained,namely,the digging angle of 20°,the dip angle of clamping carrier of 25°and the shovel length of 70 mm,with the digging resistance of 1394 N at this moment.The field digging resistance test has showed that the average digging resistance is 1543 N with the average clamping damage rate of 1.27%and the average clamping loss rate of 0.44%,which can meet the requirements of green onion harvesting.展开更多
There is evidence that ant-derived chemical stimuli are involved in regulat- ing the digging behavior in Solenopsis invicta Buren. However, the source gland（s） and chemistry of such stimuli have never been revealed....There is evidence that ant-derived chemical stimuli are involved in regulat- ing the digging behavior in Solenopsis invicta Buren. However, the source gland（s） and chemistry of such stimuli have never been revealed. In this study, extracts of mandibular, Dufour＇s, postpharyngeal, and poison glands were evaluated for their effect on ant digging and residing preferences of S. invicta workers from three colonies. In the intracolonial bioassays, workers showed significant digging preferences to mandibular gland extracts in 2 of 3 colonies and significant residing preferences in 1 of 3 colonies; significant digging preferences to Dufour＇s gland extracts in 1 of 3 colonies and significant residing preferences in 2 of 3 colonies. No digging and residing preferences were found for postpharyngeal and poison gland extracts. In intercolonial bioassays, significant digging and residing prefer- ences were found for mandibular gland extracts in 3 of 6 colony combinations. Significant digging preferences to Dufour＇s gland extracts were found in 4 of 6 colony combinations and significant residing preferences in all 6 colony combinations. For postpharyngeal gland extracts, significant digging preferences were found only in 1 of 6 colonial combinations and no significant residing preferences were found. For poison gland extracts, no signif- icant digging preferences were found; significant residing preferences were found in 1 of 6 colony combinations. However, a significant residing deterrence （negative residing preference index） was found for 2 of 6 colony combinations. Statistical analyses using data pooled from all colonies showed that mandibular and Dufour＇s gland extracts caused sig- nificant digging and residing preferences in both intracolonial and intercolonial bioassays but not postpharyngeal and poison gland extracts. By analyzing the data pooled from the same three colonies used for gland extract bioassays, it was found that, in no cases, workers showed significant digging and residing preferences to 2-ethyl-3,6-dimethylpyrazine, an alarm pheromone component from mandibular gland.展开更多
In this paper,quantitative measures for the assessment of the hydraulic excavator digging efficiency are proposed and developed.The following factors are considered:(a) boundary digging forces allowed for by the stabi...In this paper,quantitative measures for the assessment of the hydraulic excavator digging efficiency are proposed and developed.The following factors are considered:(a) boundary digging forces allowed for by the stability of an excavator,(b) boundary digging forces enabled by the driving mechanisms of the excavator,(c) factors taking into consideration the digging position in the working range of an excavator,and(d) sign and direction of potential digging resistive force.A corrected digging force is defined and a mathematical model of kinematic chain and drive mechanisms of a five-member excavator configuration was developed comprising:an undercarriage,a rotational platform and an attachment with boom,stick,and bucket.On the basis of the mathematical model of the excavator,software was developed for computation and detailed analysis of the digging forces in the entire workspace of the excavator.By using the developed software,the analysis of boundary digging forces is conducted and the corrected digging force is determined for two models of hydraulic excavators of the same mass(around 17 000 kg) with identical kinematic chain parameters but with different parameters of manipulator driving mechanisms.The results of the analysis show that the proposed set of quantitative measures can be used for assessment of the digging efficiency of existing excavator models and to serve as an optimization criterion in the synthesis of manipulator driving mechanisms of new excavator models.展开更多
A new archaeological discovery about a legendary politician from 1,800 years ago triggers heated debate No other archaeological finding in China has attracted more interest from the public than the discovery of the ...A new archaeological discovery about a legendary politician from 1,800 years ago triggers heated debate No other archaeological finding in China has attracted more interest from the public than the discovery of the tomb of Cao Cao (155-220) at the end of 2009. Cao was an important politician at the end of the Eastern Han Dynasty (25-220)展开更多
Due to the enormous utilization of solar energy,the photovoltaic(PV)system is used.The PV system is functioned based on a maximum power point(MPP).Due to the climatic change,the Partial shading conditions have occurre...Due to the enormous utilization of solar energy,the photovoltaic(PV)system is used.The PV system is functioned based on a maximum power point(MPP).Due to the climatic change,the Partial shading conditions have occurred under non-uniform irradiance conditions.In the PV system,the global maximum power point(GMPP)is complex to track in the P-V curve due to the Partial shad-ing.Therefore,several tracking processes are performed using various methods like perturb and observe(P&O),hill climbing(HC),incremental conductance(INC),Fuzzy Logic,Whale Optimization Algorithm(WOA),Grey Wolf Optimi-zation(GWO)and Flying Squirrel Search Optimization(FSSO)etc.Though,the MPPT is not so efficient when the partial shading is increased.To increase the efficiency and convergences in MMPT,the Honey Badger optimization(HBO)algorithm is presented.This HBO model is motivated by the excellent foraging behaviour of honey badgers.This HBO model is used to achieve the best solution in GMPP tracking and speed convergence.The HBO methodology is also com-pared with prior P&O,WOA and FSSO methods using MATLAB.Therefore,the experiment shows that the HBO method is performed a higher tracking than all prior methods.展开更多
基金supported by the Natural Science Foundation of Hainan Province(Grant No.520LH015)the Fundamental Research Funds for the Central Universities and the Major Projects of Strategic Emerging Industries in Shanghai(Grant No.BH3230001).
文摘To ensure the safe performance of deep-sea mining vehicles(DSMVs),it is necessary to study the mechanical characteristics of the interaction between the seabed soil and the track plate.The rotation and digging motions of the track plate are important links in the contact between the driving mechanism of the DSMV and seabed soil.In this study,a numerical simulation is conducted using the coupled Eulerian–Lagrangian(CEL)large deformation numerical method to investigate the interaction between the track plate of the DSMV and the seabed soil under two working conditions:rotating condition and digging condition.First,a soil numerical model is established based on the elastoplastic mechanical characterization using the basic physical and mechanical properties of the seabed soil obtained by in situ sampling.Subsequently,the soil disturbance mechanism and the dynamic mechanical response of the track plate under rotating and digging conditions are obtained through the analysis of the sensitivity of the motion parameters,the grouser structure,the layered soil features and the soil heterogeneity.The results indicate that the above parameters remarkably influence the interaction between the DSMV and the seabed soil.Therefore,it is important to consider the rotating and digging motion of the DSMV in practical engineering to develop a detailed optimization design of the track plate.
基金supported by the National Natural Science Foundation of China(31501175)Grants of Anhui Natural Science Foundation(20230302123239)Talent Grants of Anhui Agricultural University(RC342201).
文摘Collective behaviors efficiently impart benefits to a diversity of species ranging from bacteria to humans.Fly larvae tend to cluster and form coordinated digging groups under crowded conditions,yet understanding the rules governing this behavior is in its infancy.We primarily took advantage of the Drosophila model to investigate cooperative foraging behavior.Here,we report that Drosophila-related species and the black soldier fly have evolved a conserved strategy of cluster digging in food foraging.Subsequently,we investigated relative factors,including larval stage,population density,and food stiffness and quality,that affect the cluster digging behavior.Remarkably,oxygen supply through the posterior breathing spiracles is necessary for the organization of digging clusters.More importantly,we theoretically devise a mathematical model to accurately calculate how the cluster digging behavior expands food resources by diving depth,cross-section area,and food volume.We found that cluster digging behavior approximately increases 2.2 fold depth,1.7-fold cross-section area,and 1.9 fold volume than control groups,respectively.Amplification of food sources significantly facilitates survival,larval development,and reproductive success of Drosophila challenged with competition for limited food resources,thereby conferring trophic benefits to fitness in insects.Overall,our findings highlight that the cluster digging behavior is a pivotal behavior for their adaptation to food scarcity,advancing a better understanding of how this cooperative behavior confers fitness benefits in the animal kingdom.
基金sponsored by the National Natural Science Foundation of China(Grant No.52275258)Taishan Scholar Youth Expert Project,Qingdao City Science and Technology to Benefit the People Demonstration and Guidance Special Project(Grant No.22-3-7-xdny-14-nsh)the National Natural Science Foundation of China(Grant No.51775290).
文摘In view of the problems of easy damage and high digging resistance in the process of green onion harvesting,a mechanical model of digging green onions was established by taking the moment of digging and drawing green onions as the research object,and the main factors affecting the digging and harvesting effect were determined as the angle of digging,the dip angle of clamping carrier and the length of shovel.Thus,a complex simulation model of soil-green onion-digging mechanism system reflecting the state of harvesting was established,and the model was verified by testing soil compactness.The simulation tests were carried out by means of the complex simulation model of soil-green onion-digging mechanism system,making it clear that digging angle and the length of shovel have a extremely significant impact on the digging resistance,and the dip angle of the clamping carrier had a significant impact on the digging resistance.Through target optimization,the optimal combination of digging parameters was obtained,namely,the digging angle of 20°,the dip angle of clamping carrier of 25°and the shovel length of 70 mm,with the digging resistance of 1394 N at this moment.The field digging resistance test has showed that the average digging resistance is 1543 N with the average clamping damage rate of 1.27%and the average clamping loss rate of 0.44%,which can meet the requirements of green onion harvesting.
文摘There is evidence that ant-derived chemical stimuli are involved in regulat- ing the digging behavior in Solenopsis invicta Buren. However, the source gland（s） and chemistry of such stimuli have never been revealed. In this study, extracts of mandibular, Dufour＇s, postpharyngeal, and poison glands were evaluated for their effect on ant digging and residing preferences of S. invicta workers from three colonies. In the intracolonial bioassays, workers showed significant digging preferences to mandibular gland extracts in 2 of 3 colonies and significant residing preferences in 1 of 3 colonies; significant digging preferences to Dufour＇s gland extracts in 1 of 3 colonies and significant residing preferences in 2 of 3 colonies. No digging and residing preferences were found for postpharyngeal and poison gland extracts. In intercolonial bioassays, significant digging and residing prefer- ences were found for mandibular gland extracts in 3 of 6 colony combinations. Significant digging preferences to Dufour＇s gland extracts were found in 4 of 6 colony combinations and significant residing preferences in all 6 colony combinations. For postpharyngeal gland extracts, significant digging preferences were found only in 1 of 6 colonial combinations and no significant residing preferences were found. For poison gland extracts, no signif- icant digging preferences were found; significant residing preferences were found in 1 of 6 colony combinations. However, a significant residing deterrence （negative residing preference index） was found for 2 of 6 colony combinations. Statistical analyses using data pooled from all colonies showed that mandibular and Dufour＇s gland extracts caused sig- nificant digging and residing preferences in both intracolonial and intercolonial bioassays but not postpharyngeal and poison gland extracts. By analyzing the data pooled from the same three colonies used for gland extract bioassays, it was found that, in no cases, workers showed significant digging and residing preferences to 2-ethyl-3,6-dimethylpyrazine, an alarm pheromone component from mandibular gland.
基金Project (No 035049) partly supported by the Ministry of Education and Science of the Republic of Serbia
文摘In this paper,quantitative measures for the assessment of the hydraulic excavator digging efficiency are proposed and developed.The following factors are considered:(a) boundary digging forces allowed for by the stability of an excavator,(b) boundary digging forces enabled by the driving mechanisms of the excavator,(c) factors taking into consideration the digging position in the working range of an excavator,and(d) sign and direction of potential digging resistive force.A corrected digging force is defined and a mathematical model of kinematic chain and drive mechanisms of a five-member excavator configuration was developed comprising:an undercarriage,a rotational platform and an attachment with boom,stick,and bucket.On the basis of the mathematical model of the excavator,software was developed for computation and detailed analysis of the digging forces in the entire workspace of the excavator.By using the developed software,the analysis of boundary digging forces is conducted and the corrected digging force is determined for two models of hydraulic excavators of the same mass(around 17 000 kg) with identical kinematic chain parameters but with different parameters of manipulator driving mechanisms.The results of the analysis show that the proposed set of quantitative measures can be used for assessment of the digging efficiency of existing excavator models and to serve as an optimization criterion in the synthesis of manipulator driving mechanisms of new excavator models.
文摘A new archaeological discovery about a legendary politician from 1,800 years ago triggers heated debate No other archaeological finding in China has attracted more interest from the public than the discovery of the tomb of Cao Cao (155-220) at the end of 2009. Cao was an important politician at the end of the Eastern Han Dynasty (25-220)
文摘Due to the enormous utilization of solar energy,the photovoltaic(PV)system is used.The PV system is functioned based on a maximum power point(MPP).Due to the climatic change,the Partial shading conditions have occurred under non-uniform irradiance conditions.In the PV system,the global maximum power point(GMPP)is complex to track in the P-V curve due to the Partial shad-ing.Therefore,several tracking processes are performed using various methods like perturb and observe(P&O),hill climbing(HC),incremental conductance(INC),Fuzzy Logic,Whale Optimization Algorithm(WOA),Grey Wolf Optimi-zation(GWO)and Flying Squirrel Search Optimization(FSSO)etc.Though,the MPPT is not so efficient when the partial shading is increased.To increase the efficiency and convergences in MMPT,the Honey Badger optimization(HBO)algorithm is presented.This HBO model is motivated by the excellent foraging behaviour of honey badgers.This HBO model is used to achieve the best solution in GMPP tracking and speed convergence.The HBO methodology is also com-pared with prior P&O,WOA and FSSO methods using MATLAB.Therefore,the experiment shows that the HBO method is performed a higher tracking than all prior methods.
