Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah regi...Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah region of Togo. A two-year trial was conducted in a controlled environment at AREJ, an agro-ecological center in Cinkassé. The plant material was sorghum variety Sorvato 28. The experimental design was a Completely Randomized Block with three replications and three treatments as follows: T0 control plot (rainfed conditions);T1 (supplementary irrigation from flowering to grain filling stage) and T2 (supplementary irrigation from planting to grain filling stage). Two irrigation techniques (furrow and Californian system) were used under each watering treatment. The results showed that irrigation technique significantly affected panicle length with no effect on 1000 grains mass. Panicle length and grain yields varied from 15.59 to 25.71 cm and 0.0 to 2.06 t∙h−1, respectively, with the highest values (25.66 cm and 2.06 t∙h−1, respectively) under the T2 treatment with the California system-based supplementary irrigation. The comparison of results obtained on treatment T0 and T2, shows that supplementary irrigation increased the yields by at least 68.62%. Supplementary irrigation during sowing and growing season (T2) improved sorghum yields in the dry savannahs of Togo, with a better performance of the California irrigation system.展开更多
The plenum chamber of a heat setting machine is a key structure for distributing hot air to different air channels.Its outlet velocity uniformity directly determines the heating uniformity of textiles,significantly af...The plenum chamber of a heat setting machine is a key structure for distributing hot air to different air channels.Its outlet velocity uniformity directly determines the heating uniformity of textiles,significantly affecting the heat setting performance.In a traditional heat setting machine,the outlet airflow maldistribution of the plenum chamber still exists.In this study,a novel plenum chamber with an airfoil baffle was established to improve the uniformity of the velocity distribution at the outlet in a heat setting machine.The structural influence of the plenum chamber on the velocity distribution was investigated using a computational fluid dynamics program.It was found that a chamber with a smaller outlet partition thickness had a better outlet velocity uniformity.The structural optimization of the plenum chamber was conducted using the particle swarm optimization algorithm.The outlet partition thickness,the transverse distance and the longitudinal distance of the optimized plenum chamber were 20,686.2 and 274.6 mm,respectively.Experiments were carried out.The experimental and simulated results showed that the optimized plenum chamber with an airfoil baffle could improve the outlet velocity uniformity.The air outlet velocity uniformity index of the optimized plenum chamber with an airfoil baffle was 4.75%higher than that of the plenum chamber without an airfoil baffle and 5.98%higher than that of the conventional chamber with a square baffle in a commercial heat setting machine.展开更多
Goal-conditioned reinforcement learning(RL)is an interesting extension of the traditional RL framework,where the dynamic environment and reward sparsity can cause conventional learning algorithms to fail.Reward shapin...Goal-conditioned reinforcement learning(RL)is an interesting extension of the traditional RL framework,where the dynamic environment and reward sparsity can cause conventional learning algorithms to fail.Reward shaping is a practical approach to improving sample efficiency by embedding human domain knowledge into the learning process.Existing reward shaping methods for goal-conditioned RL are typically built on distance metrics with a linear and isotropic distribution,which may fail to provide sufficient information about the ever-changing environment with high complexity.This paper proposes a novel magnetic field-based reward shaping(MFRS)method for goal-conditioned RL tasks with dynamic target and obstacles.Inspired by the physical properties of magnets,we consider the target and obstacles as permanent magnets and establish the reward function according to the intensity values of the magnetic field generated by these magnets.The nonlinear and anisotropic distribution of the magnetic field intensity can provide more accessible and conducive information about the optimization landscape,thus introducing a more sophisticated magnetic reward compared to the distance-based setting.Further,we transform our magnetic reward to the form of potential-based reward shaping by learning a secondary potential function concurrently to ensure the optimal policy invariance of our method.Experiments results in both simulated and real-world robotic manipulation tasks demonstrate that MFRS outperforms relevant existing methods and effectively improves the sample efficiency of RL algorithms in goal-conditioned tasks with various dynamics of the target and obstacles.展开更多
Long-term thermal stability of a series of Zr-based metallic glasses with different oxygen contents below their glass transition temperatures was compared based on their deductive continuous-heating-transformation dia...Long-term thermal stability of a series of Zr-based metallic glasses with different oxygen contents below their glass transition temperatures was compared based on their deductive continuous-heating-transformation diagrams created by using the corollary of Kissinger analysis method. It is found that the influence of oxygen on the long-term thermal stability of Zr-based metallic glasses exhibits at lower temperature is different from that on their short-term thermal stability presented at higher temperature. For each kind of the Zr-based metallic glasses, there is a critical heating rate, φ , which corresponds to a critical c temperature, Tc. As heating rate is smaller than φ c and onset devitrification temperature is below Tc, the glass with higher oxygen content will have longer incubation period for onset devitrification. The values of φ c and Tc are related with the glasses’ reduced glass transition temperature Trg. The improving effect of oxygen impurity on the long-term thermal stability of Zr-based metallic glasses was discovered.展开更多
taking the bucket of multi function earth drill as an example, combining with the conception of multi sensor integration and data fusion, adopting the terrene column chart and digging torque formula as control depende...taking the bucket of multi function earth drill as an example, combining with the conception of multi sensor integration and data fusion, adopting the terrene column chart and digging torque formula as control dependence, the detecting method of the earth drill’s working state is introduced. Multi sensor data fusion is done with the aid of BP neural network in Matlab. The data to be interfused are pre processed and the program of simulation and “point checking” is given.展开更多
The pathogen plays an important role in spreading infection and bad impact on the public health of the river. Therefore, water quality as a model is used to simulate the spreading and fate of the pathogen in Lijiang R...The pathogen plays an important role in spreading infection and bad impact on the public health of the river. Therefore, water quality as a model is used to simulate the spreading and fate of the pathogen in Lijiang River, it is located in Lijiang City, Yunnan Province, China (100°25'E, 26°86'N). Even at low bacterial levels, there is a risk of pathogens in the Lijiang River ecosystem. The water quality model results showed that the spatiotemporal (space and time) migration of pathogenic bacteria in Lijiang River from 2005 to 2015 was quantitatively revealed by the model simulation. The simulation results also showed that the transports of pathogenic bacteria in Lijiang River are extremely sensitive to the speed distribution and seasonal temperature characteristics. The study found that the rising water temperature in spring leads to a sharp rise in the concentration of pathogenic bacteria. When the water temperature is low in winter, the simulated pathogenic bacteria are relatively stable, which is lower than the concentration of pathogenic bacteria at high temperature. If the spring water temperature rises, the flow rate increases, the concentration of pathogenic bacteria accordingly increases. This research recommends the development of best management practices to control microbial growth in river basins.展开更多
This study was carried out in the University of Campinas to study the three-dimensional reconstruction of grape bunches through the application of the Moire technique as an alternative and innovative method, using low...This study was carried out in the University of Campinas to study the three-dimensional reconstruction of grape bunches through the application of the Moire technique as an alternative and innovative method, using low-cost equipment for data acquisition. This study proposed the three-dimensional visualization of grapes and topography on Xi axes through the Moire projection technique. The artificial grapes with a 20 cm long bunch and 18.45 mm average diameter for each grape were used. A projector was used to generate a grid with light and dark lines. The grape bunch was placed on a holder, illuminated by a sinusoidal grid and photographed. After processing the images, a three-dimensional map of the fruit and topography on Xi axes were obtained. The three-dimensional fruit observation allows the visualization of the higher and lower regions of the three-dimensional configuration through a color map. This result makes it possible to obtain size and shape of the grape bunch, allowing for the process automation of product selection and classification.展开更多
Handroanthus heptaphyllus （botany synonymy Tabebuia heptaphylla） is considered to have very important economical,ornamental and medicinal value. It is included in the Bignoniaceae botanical family, whose multiplicat...Handroanthus heptaphyllus （botany synonymy Tabebuia heptaphylla） is considered to have very important economical,ornamental and medicinal value. It is included in the Bignoniaceae botanical family, whose multiplication is quite solely carried byseeds. Forest dispersion elements, i.e., the seeds, deserve a deep understanding on their physiological performance. The objective ofthis research work was to determine the optimum seed moisture content for laser interaction in biospeckle tests, which is based onlaser interferometry. Seeds were hydrated to the level of 69% and then divided into four subsamples, i.e., （1） seeds without teguments,（2） seeds with tegument, （3） seeds without teguments frozen at 0 ℃ and （4） seeds with teguments frozen at 0 ℃. The foursubsamples were then separated into five moisture level groups （28%, 35%, 54%, 63% and 69%） and exposed to the laser. Thebiospeckle phenomenon quantification was carried out by means of the moment of inertia （MI） approach. A positive correlationbetween MI and seed moisture content was obtained. It was also verified that seed moisture content between 28% and 54% showedbetter interaction with the laser. The results are important for the application of the biospeckle technique as a possible tool to assessthe quality of purple ipe seeds.展开更多
Based on the refined dynamic equation of stretching plates, the elastic tensio compression wave scattering and dynamic stress concentrations in the thick plate with two cutouts are studied. In view of the problem that...Based on the refined dynamic equation of stretching plates, the elastic tensio compression wave scattering and dynamic stress concentrations in the thick plate with two cutouts are studied. In view of the problem that the shear stress is automatically satisfied under the free boundary condition, the generalized stress of the first-order vanishing moment of shear stress is considered. The numerical results indicate that, as the cutout is thick, the maximum value of the dynamic stress factor obtained using the refined dynamic theory is 19% higher than that from the solution of plane stress problems of elastic dynamics.展开更多
A resonant buildup of beam-induced fields in a superconducting radio frequency （RF） cavity may make a beam unstable or a superconducting RF cavity quench. Higher-order mode （HOM） couplers are used for damping high...A resonant buildup of beam-induced fields in a superconducting radio frequency （RF） cavity may make a beam unstable or a superconducting RF cavity quench. Higher-order mode （HOM） couplers are used for damping higher-order modes to avoid such a resonant buildup. A coaxial HOM coupler based on the TTF （TESLA Test Facility） HOM coupler has been designed for the superconducting RF cavities at the Proton Engineering Frontier Project （PEFP） in order to overcome notch frequency shift and feed-through tip melting issues. In order to confirm the HOM coupler design and finalize its structural dimensions, two prototype HOM couplers have been fabricated and tested. Low-power testing and measurement of the HOM couplers has shown that the HOM coupler has good filter properties and can fully meet the damping requirements of the PEFP low-beta superconducting RF linac.展开更多
文摘Under the current context of climate change, supplementary irrigation may be needed for crop production resilience. We determined the effects of supplementary irrigation on sorghum grain yield in the dry Savannah region of Togo. A two-year trial was conducted in a controlled environment at AREJ, an agro-ecological center in Cinkassé. The plant material was sorghum variety Sorvato 28. The experimental design was a Completely Randomized Block with three replications and three treatments as follows: T0 control plot (rainfed conditions);T1 (supplementary irrigation from flowering to grain filling stage) and T2 (supplementary irrigation from planting to grain filling stage). Two irrigation techniques (furrow and Californian system) were used under each watering treatment. The results showed that irrigation technique significantly affected panicle length with no effect on 1000 grains mass. Panicle length and grain yields varied from 15.59 to 25.71 cm and 0.0 to 2.06 t∙h−1, respectively, with the highest values (25.66 cm and 2.06 t∙h−1, respectively) under the T2 treatment with the California system-based supplementary irrigation. The comparison of results obtained on treatment T0 and T2, shows that supplementary irrigation increased the yields by at least 68.62%. Supplementary irrigation during sowing and growing season (T2) improved sorghum yields in the dry savannahs of Togo, with a better performance of the California irrigation system.
基金National Natural Science Foundation of China(No.62173307)the Key R&D Projects of Science and Technology Department of Zhejiang Province,China(Nos.2023C01158,2022C01065 and 2022C01188)the Fundamental Research Funds of Zhejiang Sci-Tech University,China(No.22242298-Y)。
文摘The plenum chamber of a heat setting machine is a key structure for distributing hot air to different air channels.Its outlet velocity uniformity directly determines the heating uniformity of textiles,significantly affecting the heat setting performance.In a traditional heat setting machine,the outlet airflow maldistribution of the plenum chamber still exists.In this study,a novel plenum chamber with an airfoil baffle was established to improve the uniformity of the velocity distribution at the outlet in a heat setting machine.The structural influence of the plenum chamber on the velocity distribution was investigated using a computational fluid dynamics program.It was found that a chamber with a smaller outlet partition thickness had a better outlet velocity uniformity.The structural optimization of the plenum chamber was conducted using the particle swarm optimization algorithm.The outlet partition thickness,the transverse distance and the longitudinal distance of the optimized plenum chamber were 20,686.2 and 274.6 mm,respectively.Experiments were carried out.The experimental and simulated results showed that the optimized plenum chamber with an airfoil baffle could improve the outlet velocity uniformity.The air outlet velocity uniformity index of the optimized plenum chamber with an airfoil baffle was 4.75%higher than that of the plenum chamber without an airfoil baffle and 5.98%higher than that of the conventional chamber with a square baffle in a commercial heat setting machine.
基金supported in part by the National Natural Science Foundation of China(62006111,62073160)the Natural Science Foundation of Jiangsu Province of China(BK20200330)。
文摘Goal-conditioned reinforcement learning(RL)is an interesting extension of the traditional RL framework,where the dynamic environment and reward sparsity can cause conventional learning algorithms to fail.Reward shaping is a practical approach to improving sample efficiency by embedding human domain knowledge into the learning process.Existing reward shaping methods for goal-conditioned RL are typically built on distance metrics with a linear and isotropic distribution,which may fail to provide sufficient information about the ever-changing environment with high complexity.This paper proposes a novel magnetic field-based reward shaping(MFRS)method for goal-conditioned RL tasks with dynamic target and obstacles.Inspired by the physical properties of magnets,we consider the target and obstacles as permanent magnets and establish the reward function according to the intensity values of the magnetic field generated by these magnets.The nonlinear and anisotropic distribution of the magnetic field intensity can provide more accessible and conducive information about the optimization landscape,thus introducing a more sophisticated magnetic reward compared to the distance-based setting.Further,we transform our magnetic reward to the form of potential-based reward shaping by learning a secondary potential function concurrently to ensure the optimal policy invariance of our method.Experiments results in both simulated and real-world robotic manipulation tasks demonstrate that MFRS outperforms relevant existing methods and effectively improves the sample efficiency of RL algorithms in goal-conditioned tasks with various dynamics of the target and obstacles.
基金Project(50671076) supported by the National Natural Science Foundation of China
文摘Long-term thermal stability of a series of Zr-based metallic glasses with different oxygen contents below their glass transition temperatures was compared based on their deductive continuous-heating-transformation diagrams created by using the corollary of Kissinger analysis method. It is found that the influence of oxygen on the long-term thermal stability of Zr-based metallic glasses exhibits at lower temperature is different from that on their short-term thermal stability presented at higher temperature. For each kind of the Zr-based metallic glasses, there is a critical heating rate, φ , which corresponds to a critical c temperature, Tc. As heating rate is smaller than φ c and onset devitrification temperature is below Tc, the glass with higher oxygen content will have longer incubation period for onset devitrification. The values of φ c and Tc are related with the glasses’ reduced glass transition temperature Trg. The improving effect of oxygen impurity on the long-term thermal stability of Zr-based metallic glasses was discovered.
文摘taking the bucket of multi function earth drill as an example, combining with the conception of multi sensor integration and data fusion, adopting the terrene column chart and digging torque formula as control dependence, the detecting method of the earth drill’s working state is introduced. Multi sensor data fusion is done with the aid of BP neural network in Matlab. The data to be interfused are pre processed and the program of simulation and “point checking” is given.
文摘The pathogen plays an important role in spreading infection and bad impact on the public health of the river. Therefore, water quality as a model is used to simulate the spreading and fate of the pathogen in Lijiang River, it is located in Lijiang City, Yunnan Province, China (100°25'E, 26°86'N). Even at low bacterial levels, there is a risk of pathogens in the Lijiang River ecosystem. The water quality model results showed that the spatiotemporal (space and time) migration of pathogenic bacteria in Lijiang River from 2005 to 2015 was quantitatively revealed by the model simulation. The simulation results also showed that the transports of pathogenic bacteria in Lijiang River are extremely sensitive to the speed distribution and seasonal temperature characteristics. The study found that the rising water temperature in spring leads to a sharp rise in the concentration of pathogenic bacteria. When the water temperature is low in winter, the simulated pathogenic bacteria are relatively stable, which is lower than the concentration of pathogenic bacteria at high temperature. If the spring water temperature rises, the flow rate increases, the concentration of pathogenic bacteria accordingly increases. This research recommends the development of best management practices to control microbial growth in river basins.
文摘This study was carried out in the University of Campinas to study the three-dimensional reconstruction of grape bunches through the application of the Moire technique as an alternative and innovative method, using low-cost equipment for data acquisition. This study proposed the three-dimensional visualization of grapes and topography on Xi axes through the Moire projection technique. The artificial grapes with a 20 cm long bunch and 18.45 mm average diameter for each grape were used. A projector was used to generate a grid with light and dark lines. The grape bunch was placed on a holder, illuminated by a sinusoidal grid and photographed. After processing the images, a three-dimensional map of the fruit and topography on Xi axes were obtained. The three-dimensional fruit observation allows the visualization of the higher and lower regions of the three-dimensional configuration through a color map. This result makes it possible to obtain size and shape of the grape bunch, allowing for the process automation of product selection and classification.
文摘Handroanthus heptaphyllus （botany synonymy Tabebuia heptaphylla） is considered to have very important economical,ornamental and medicinal value. It is included in the Bignoniaceae botanical family, whose multiplication is quite solely carried byseeds. Forest dispersion elements, i.e., the seeds, deserve a deep understanding on their physiological performance. The objective ofthis research work was to determine the optimum seed moisture content for laser interaction in biospeckle tests, which is based onlaser interferometry. Seeds were hydrated to the level of 69% and then divided into four subsamples, i.e., （1） seeds without teguments,（2） seeds with tegument, （3） seeds without teguments frozen at 0 ℃ and （4） seeds with teguments frozen at 0 ℃. The foursubsamples were then separated into five moisture level groups （28%, 35%, 54%, 63% and 69%） and exposed to the laser. Thebiospeckle phenomenon quantification was carried out by means of the moment of inertia （MI） approach. A positive correlationbetween MI and seed moisture content was obtained. It was also verified that seed moisture content between 28% and 54% showedbetter interaction with the laser. The results are important for the application of the biospeckle technique as a possible tool to assessthe quality of purple ipe seeds.
基金supported by the Natural Science Foundation of Zhejiang Province of China (Grant No. LQ17E050011)the National Natural Science Foundation of China (Grant No. 51775154)+1 种基金the Natural Science Foundation of Zhejiang Province of China (Grant No.LQ17E090007)the Key Project of Natural Science Foundation of Zhejiang Province of China (Grant No. LQ17E050011)
文摘Based on the refined dynamic equation of stretching plates, the elastic tensio compression wave scattering and dynamic stress concentrations in the thick plate with two cutouts are studied. In view of the problem that the shear stress is automatically satisfied under the free boundary condition, the generalized stress of the first-order vanishing moment of shear stress is considered. The numerical results indicate that, as the cutout is thick, the maximum value of the dynamic stress factor obtained using the refined dynamic theory is 19% higher than that from the solution of plane stress problems of elastic dynamics.
文摘A resonant buildup of beam-induced fields in a superconducting radio frequency （RF） cavity may make a beam unstable or a superconducting RF cavity quench. Higher-order mode （HOM） couplers are used for damping higher-order modes to avoid such a resonant buildup. A coaxial HOM coupler based on the TTF （TESLA Test Facility） HOM coupler has been designed for the superconducting RF cavities at the Proton Engineering Frontier Project （PEFP） in order to overcome notch frequency shift and feed-through tip melting issues. In order to confirm the HOM coupler design and finalize its structural dimensions, two prototype HOM couplers have been fabricated and tested. Low-power testing and measurement of the HOM couplers has shown that the HOM coupler has good filter properties and can fully meet the damping requirements of the PEFP low-beta superconducting RF linac.
