Banana (Musa spp.) is a highly perishable fruit that requires special handling. In Eritrea, post-harvest handling practices are characterized to be poor and as a result, poor fruit quality and high post-harvest loss a...Banana (Musa spp.) is a highly perishable fruit that requires special handling. In Eritrea, post-harvest handling practices are characterized to be poor and as a result, poor fruit quality and high post-harvest loss are common. Thus, the purpose of this study was to evaluate the effect of different post-harvest handling and ripening methods on quality and shelf-life of banana. A Complete Randomized Design (CRD) was used for evaluating a combination of two levels of post-harvest handling and four ripening methods in a factorial combination conducted in the laboratory of Horticulture at Hamelmalo Agricultural College. Peel colour change, physiological weight loss, pulp to peel ratio, total soluble solids (TSS), pulp pH, ripening period and shelf life were parameters studied. The results showed fruits treated with ripened tomato showed improved characteristics in all parameters compared to those treated with smoke from kerosene burning or mixed with moringa leaf. Similarly, fruits brought directly from the farm were better than those collected from the ripening room after passing the conventional post-harvest handling. Based on the results of this study, it can be concluded that ripening of banana with the help of tomato improves fruit quality and shelf life. Thus, it can be a safe and better alternative to smoking from kerosene burning. While moringa leaf has no potential as an alternative.展开更多
A cross-sectional study was carried out to assess hygienic production and postharvest handling practices of raw camel milk in Degahbour district. The survey studies were based on a total of 120 (2 production systems *...A cross-sectional study was carried out to assess hygienic production and postharvest handling practices of raw camel milk in Degahbour district. The survey studies were based on a total of 120 (2 production systems * 2 rural kebele * 30 households) milk producers, which were selected from Degahbur district using stratified sampling technique. Data from the selected producers were collected using questionnaire survey and field observation. The results showed that the majority of the sampled household heads in pastoral (93.3%) and agro-pastoral (76.6%) production systems were illiterate. Moreover, none of the respondents in the study area had training on hygienic milk production and postharvest handling practices. The study result also indicated that none of the respondents in the study area washed the udder of milking camel before milking. Moreover, only 6.6% of pastoralists and 25% of agro-pastoralists wash their hands before milking. Equipment made of wooden materials are mainly used for milking, whereas, plastic jerry-cans were most commonly used for storage. About 45% of the pastoralists and 81.6% of the agro-pastoralists were cleaning milk vessels regularly;however, majority of the respondents both production systems were using water from non-tap sources for hygienic practices. Bosciaminimifolia, Acacia ethaica and Blanitesgalabra were the most commonly used plant species for smoking in the study area. Therefore, hygienic production and postharvest handling practices should be followed to improve the quality and suitability of camel milk for its intended use in the study area.展开更多
Mechanical damage induced by vibration during harvesting and post-harvest handling could decrease the quality,quantity,and shelf life of the fresh grape cluster.Usually,fresh grape clusters are harvested by gripping a...Mechanical damage induced by vibration during harvesting and post-harvest handling could decrease the quality,quantity,and shelf life of the fresh grape cluster.Usually,fresh grape clusters are harvested by gripping and cutting from the main rachis in the present robotic harvesting system,then transported towards the basket during post-harvest handling.However,serious cluster vibration and corresponding berry falling may occur during the robotic transportation of hanging grape clusters.Therefore,this study was designed to perform experimental and theoretical hanging force analysis to explore the vibration mechanism of hanging grape clusters during robotic transportation.A lead screw lathe with an attached linear actuator was used to investigate the effects of four different speeds(0.4,0.6,0.8,1.0 m/s)with four acceleration levels(6,8,10,12 m/s2)on the vibration of the hanging grape cluster.By the experiments,the peak hanging force of the grape cluster at the start,constant speed,and stop phase of the actuator was recorded using a single axis force sensor,and the cluster’s swing angle was measured with a digital camera.The experimental results showed a linear relationship between the swing angle and hanging force of the cluster at the start and stop phase of the actuator.The multi-stage cluster’s vibration during robotic transportation was observed,and the behavior of cycled damping after a sudden stop of the actuator was found.The simulated results of hanging force of grape cluster in damping phase were agreed with experimental results with R2 more than 0.90 at an optimum acceleration of 10 m/s2.To conclude,this research provides theoretical basics for understanding the complex vibration mechanism of the hanging cluster fruits during speedy robotic transportation operations with low-loss of berry drop both on industrial and farm levels.展开更多
The need to transport goods across countries and islands has resulted in a high demand for commercial vessels.Owing to such trends,shipyards must efficiently produce ships to reduce production costs.Layout and materia...The need to transport goods across countries and islands has resulted in a high demand for commercial vessels.Owing to such trends,shipyards must efficiently produce ships to reduce production costs.Layout and material flow are among the crucial aspects determining the efficiency of the production at a shipyard.This paper presents the initial design optimization of a shipyard layout using Nondominated Sorting Algorithm-Ⅱ(NSGA-Ⅱ)to find the optimal configuration of workstations in a shipyard layout.The proposed method focuses on simultaneously minimizing two material handling costs,namely work-based material handling and duration-based material handling.NSGA-Ⅱ determines the order of workstations in the shipyard layout.The semiflexible bay structure is then used in the workstation placement process from the sequence formed in NSGA-Ⅱ into a complete design.Considering that this study is a case of multiobjective optimization,the performance for both objectives at each iteration is presented in a 3D graph.Results indicate that after 500 iterations,the optimal configuration yields a work-based MHC of 163670.0 WBM-units and a duration-based MHC of 34750 DBM-units.Starting from a random solution,the efficiency of NSGA-Ⅱ demonstrates significant improvements,achieving a 50.19%reduction in work-based MHC and a 48.58%reduction in duration-based MHC.展开更多
Objective:Arrhythmia-induced cardiomyopathy(AIC)is a reversible dilated cardiomyopathy induced by rapid or irregular heartbeat.Acupuncture has a long history of use in the treatment of cardiac diseases,and Xinshu(BL15...Objective:Arrhythmia-induced cardiomyopathy(AIC)is a reversible dilated cardiomyopathy induced by rapid or irregular heartbeat.Acupuncture has a long history of use in the treatment of cardiac diseases,and Xinshu(BL15)is a key acupoint.However,the underlying mechanism of acupuncture at BL15 in the treatment of AIC has not yet been elucidated.Methods:AIC was induced in adult male Sprague-Dawley(SD)rats by continuous administration of acetylcholine(ACh)-CaCl2 and treatment with electroacupuncture(EA)at bilateral BL15.Echocardiography was used to evaluate cardiac function;the rotarod test for motor coordination and performance;hematoxylin and eosin(HE)staining for the morphology of ventricles;electrocardiogram for susceptibility,inducibility,and duration of atrial fibrillation(AF);and electrical and optical mapping in isolated rat hearts maintained by the Langendorff perfusion system for electrical conduction and intracellular handling,respectively.Reverse transcription quantitative polymerase chain reaction(RT-qPCR)and Western blotting were used to determine the levels of cardiac conduction and intracellular calcium-handling proteins in the ventricle.Results:The results showed that EA improved the ejection factor and morphological indices on echocardiography,restored motor coordination and performance,and alleviated ventricular dilation and AF onset.EA alleviates atrial conduction disorders,shortens APD80,and decreases calcium handling in rats with AIC.Cx43 was downregulated and CaMKII was upregulated,and both effects were reversed by EA treatment.Conclusion:Our study provides a novel AIC model with abnormal electrical propagation and calcium handling that can be protected by EA at BL15.This potential mechanism may be associated with the modulation of Cx43 and CaMKII expression.展开更多
This paper introduces an intelligent garbage-handling trolley model based on an STM32 single chip microcomputer as the control core.The device is driven by four independent motors to achieve automatic tracking,automat...This paper introduces an intelligent garbage-handling trolley model based on an STM32 single chip microcomputer as the control core.The device is driven by four independent motors to achieve automatic tracking,automatic obstacle avoidance,and fixed-point docking.Using external execution structure to realize the car without the use of a mechanical arm,complete garbage collection,storage,and uninstall function.On this basis,the type of garbage is marked by color,and the color recognition sensor is applied to realize the type recognition after garbage collection and put into the corresponding unloading point,to realize its intelligent classification function.It can automatically complete the established task autonomously.展开更多
Object detection in occluded environments remains a core challenge in computer vision(CV),especially in domains such as autonomous driving and robotics.While Convolutional Neural Network(CNN)-based twodimensional(2D)a...Object detection in occluded environments remains a core challenge in computer vision(CV),especially in domains such as autonomous driving and robotics.While Convolutional Neural Network(CNN)-based twodimensional(2D)and three-dimensional(3D)object detection methods havemade significant progress,they often fall short under severe occlusion due to depth ambiguities in 2D imagery and the high cost and deployment limitations of 3D sensors such as Light Detection and Ranging(LiDAR).This paper presents a comparative review of recent 2D and 3D detection models,focusing on their occlusion-handling capabilities and the impact of sensor modalities such as stereo vision,Time-of-Flight(ToF)cameras,and LiDAR.In this context,we introduce FuDensityNet,our multimodal occlusion-aware detection framework that combines Red-Green-Blue(RGB)images and LiDAR data to enhance detection performance.As a forward-looking direction,we propose a monocular depth-estimation extension to FuDensityNet,aimed at replacing expensive 3D sensors with a more scalable CNN-based pipeline.Although this enhancement is not experimentally evaluated in this manuscript,we describe its conceptual design and potential for future implementation.展开更多
The cooperative control of ride comfort and handling stability in automobile suspension systems presents a significant challenge in intelligent chassis system design.This complexity arises from the high degrees of fre...The cooperative control of ride comfort and handling stability in automobile suspension systems presents a significant challenge in intelligent chassis system design.This complexity arises from the high degrees of freedom,diverse operating conditions,and inherent trade-offs between performance metrics in full-car suspension systems.In this paper,a novel switching control strategy is proposed to better balance ride comfort and handling stability for a full-car suspension system.The system integrates a ride comfort controller and an anti-rollover controller,guided by a new rollover risk assessment indicator that requires fewer state variables.First,a vehicle suspension simplification model approach is introduced,reducing the fourteen-degree-of-freedom full-car suspension model to three two-degree-of-freedom models:vertical,pitch and roll.Based on these simplified models,vertical,roll,and pitch controllers are designed,simplifying the controller design process for full-car suspension systems.The ride comfort controller is constructed using the modal energy method in conjunction with the simplified model controllers,while the roll controller functions as the anti-rollover controller.The proposed rollover risk assessment indicator serves as the switching criterion between handling stability and ride comfort control.Experimental results demonstrate that the proposed switching control strategy effectively adapts to various road conditions,enabling the semi-active variable damping suspension system to perform multi-modal switching.Compared to a well-tuned passive suspension,vertical,roll,and pitch accelerations are reduced by 14.13%,13.02%and 13.08%,respectively,significantly improving ride comfort.Additionally,the system effectively mitigates rollover risk,achieving reductions in roll angle,roll speed,and roll acceleration by 19.69%,16.40%,and 29.96%,respectively,thereby greatly enhancing vehicle safety.Overall,the proposed switching control strategy achieves a successful balance between ride comfort and handling stability,enhancing overall driving performance.展开更多
Aiming at various faults in an air conditioning system,the fault characteristics are analyzed.The influence of the faults on the energy consumption and thermal comfort of the system are also discussed.The simulation r...Aiming at various faults in an air conditioning system,the fault characteristics are analyzed.The influence of the faults on the energy consumption and thermal comfort of the system are also discussed.The simulation results show that the measurement faults of the supply air temperature can lead to the increase in energy consumption.According to the fault characteristics,a data-driven method based on a neural network is presented to detect and diagnose the faults of air handling units.First,the historical data are selected to train the neural network so that it can recognize and predict the operation of the system.Then,the faults can be diagnosed by calculating the relative errors denoting the difference between the measuring values and the prediction outputs.Finally,the fault diagnosis strategy using the neural network is validated by using a simulator based on the TRNSYS platform.The results show that the neural network can diagnose different faults of the temperature,the flow rate and the pressure sensors in the air conditioning system.展开更多
A DC to 5GHz series MEMS switch is designed and fabricated for wireless communication applications,and thermal effect and power handling of the series switch are discussed.The switch is made on glass substrate,and gol...A DC to 5GHz series MEMS switch is designed and fabricated for wireless communication applications,and thermal effect and power handling of the series switch are discussed.The switch is made on glass substrate,and gold platinum contact is used to get a stable and little insert loss.From DC to 5GHz,0 6dB insertion loss,30dB isolation,and 30μs delay are demonstrated.Thermal effect of the switch is tested in 85℃ and -55℃ atmosphere separately.From DC to 4GHz,the insert loss of the switch increases 0 2dB in 85℃ and 0 4dB in -55℃,while the isolation holds the same value as that in room temperature.To measure the power handling capability of the switch,we applied a continuous RF power increasing from 10dBm to 35 1dBm with the step of 1 0dBm across the switch at 4GHz.The switch keeps working and shows a decrease of the insert loss for 0 1～0 6dB.The maximum continuous power handling (35 1dBm,about 3 24W) is higer than the reported value of shunt switch (about 420mW),which implies series switches have much better power handling capability.展开更多
To solve the problems that the exception handling code is hard to test and maintain and that it affects the robustness and reliability of software, a method for evaluating the exception handling of programs is present...To solve the problems that the exception handling code is hard to test and maintain and that it affects the robustness and reliability of software, a method for evaluating the exception handling of programs is presented. The exception propagation graph （EPG） that describes the large programs with exception handling constructs is proposed by simplifying the control flow graph and it is applied to a case to verify its validity. According to the EPG, the exception handling code that never executes is identified; the points that are the most critical to controlling exception propagation are found; and the irrational exception handling code is corrected. The constructing algorithm for the EPG is given; thus, this provides a basis for automatically constructing the EPG and automatically correcting the irrational exception handling code.展开更多
Objectives: This paper examines the basic knowledge ofAIDS and HIV transmission through unsafe blood collec-tion and supply among rural Chinese doctors. It also ex-plores the accessibility of AIDS intervention methods...Objectives: This paper examines the basic knowledge ofAIDS and HIV transmission through unsafe blood collec-tion and supply among rural Chinese doctors. It also ex-plores the accessibility of AIDS intervention methods inrural area. Methods: We did Case studies, held focus group discus-sions and provided questionnaires to all rural doctors inone township where the epidemic of HIV was known to bespread through blood collection and supply. Data were col-lected and analyzed with software EPI 6.0.Results: The effective response rate to the questionnairewas 100%. The results showed that more than 95% of in-formants gave correct answers to the questions about thesexual and blood-bourne transmission of HIV as well as itscontagiousness. Half of the participants were ignorant aboutmother to child transmission of HIV and did not know thatHIV couldn’t be transmitted by saliva, sweat, mosquito bites,sharing of bathtubs or toilets. More than 80% of infor-mants were opposed to blood selling and reportedly under-stood the objective of the blood organizers in their villages,knew the peak time of blood selling by the villagers, and ,were aware of the risks of diseases being spread throughblood. . 27.3% used disposable syringes ‘once in a while’,and 15.2% discarded or sold used disposable syringes.Conclusions: The authors assert that there are severe lurk-ing perils of iatrogenic cross infection in rural areas. Ruraldoctors urgently need formal training on prevention andtreatment of HIV infection. We believe that rural doctorsshould become the key force in AIDS prevention and con-trol in rural area.展开更多
In some non-human primates, infants function as a social tool that can bridge relationships among group members. Infants are a desired commodity for group members, and mothers control access to them. The biological ma...In some non-human primates, infants function as a social tool that can bridge relationships among group members. Infants are a desired commodity for group members, and mothers control access to them. The biological market theory suggests that grooming is widespread and represents a commodity that can be exchanged for infant handling. As a limited resource, however, the extent to which infants are interchanged between mothers(females with an infant) and non-mothers(potential handlers,females without an infant) remains unclear. In this study, we collected behavioral data to investigate the relationship between grooming and infant handling in free-ranging Tibetan macaques(Macaca thibetana)at Mt. Huangshan, China. Our results showed that females with infants received more grooming than females without infants. After her infant was handled,mother females received more grooming than they did during daily grooming interactions. However, with the increasing number of infants within the social group, both the grooming that mothers received and the grooming that non-mothers invested for handling infants decreased. We also found that non-mothers invested more time in grooming to gain access to younger infants than older infants. Our results provide evidence that infants are social commodities for both mother and non-mother females. Mothers use infants for obtain grooming and non-mothers use grooming to gain access to infants. The current study implies a bidirectional and complex interchange pattern between grooming and infant handling to compensate for the dyadic grooming disparity in non-human primates.展开更多
Compared with traditional mechanical seals,magnetic fluid seals have unique characters of high airtightness,minimal friction torque requirements,pollution-free and long life-span,widely used in vacuum robots.With the ...Compared with traditional mechanical seals,magnetic fluid seals have unique characters of high airtightness,minimal friction torque requirements,pollution-free and long life-span,widely used in vacuum robots.With the rapid development of Integrate Circuit（IC）,there is a stringent requirement for sealing wafer-handling robots when working in a vacuum environment.The parameters of magnetic fluid seals structure is very important in the vacuum robot design.This paper gives a magnetic fluid seal device for the robot.Firstly,the seal differential pressure formulas of magnetic fluid seal are deduced according to the theory of ferrohydrodynamics,which indicate that the magnetic field gradient in the sealing gap determines the seal capacity of magnetic fluid seal.Secondly,the magnetic analysis model of twin-shaft magnetic fluid seals structure is established.By analyzing the magnetic field distribution of dual magnetic fluid seal,the optimal value ranges of important parameters,including parameters of the permanent magnetic ring,the magnetic pole tooth,the outer shaft,the outer shaft sleeve and the axial relative position of two permanent magnetic rings,which affect the seal differential pressure,are obtained.A wafer-handling robot equipped with coaxial twin-shaft magnetic fluid rotary seals and bellows seal is devised and an optimized twin-shaft magnetic fluid seals experimental platform is built.Test result shows that when the speed of the two rotational shafts ranges from 0-500 r/min,the maximum burst pressure is about 0.24 MPa.Magnetic fluid rotary seals can provide satisfactory performance in the application of wafer-handling robot.The proposed coaxial twin-shaft magnetic fluid rotary seal provides the instruction to design high-speed vacuum robot.展开更多
For a distributed drive electric vehicle(DDEV)driven by four in-wheel motors,advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently,quickly and precisely.And dir...For a distributed drive electric vehicle(DDEV)driven by four in-wheel motors,advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently,quickly and precisely.And direct yaw-moment control(DYC)has been widely studied and applied to vehicle stability control.Good vehicle handling performance:quick yaw rate transient response,small overshoot,high steady yaw rate gain,etc,is required by drivers under normal conditions,which is less concerned,however.Based on the hierarchical control methodology,a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed.The upper-loop control system consists of two parts:a state feedback controller,which aims to realize the ideal transient response of yaw rate,with a vehicle sideslip angle observer;and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain.Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors,the integrated time and absolute error(ITAE)function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix.Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method:yaw rate rising time is reduced,steady yaw rate gain is increased,vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced.The control system improves vehicle handling performance under normal conditions in both transient and steady response.State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.展开更多
This paper presents a novel five degrees of freedom (DOF) two-wheeled robotic machine (TWRM) that delivers solutions for both industrial and service robotic applications by enlarging the vehicle′s workspace and incre...This paper presents a novel five degrees of freedom (DOF) two-wheeled robotic machine (TWRM) that delivers solutions for both industrial and service robotic applications by enlarging the vehicle′s workspace and increasing its flexibility. Designing a two-wheeled robot with five degrees of freedom creates a high challenge for the control, therefore the modelling and design of such robot should be precise with a uniform distribution of mass over the robot and the actuators. By employing the Lagrangian modelling approach, the TWRM′s mathematical model is derived and simulated in Matlab/Simulink?. For stabilizing the system′s highly nonlinear model, two control approaches were developed and implemented: proportional-integral-derivative (PID) and fuzzy logic control (FLC) strategies. Considering multiple scenarios with different initial conditions, the proposed control strategies′ performance has been assessed.展开更多
A control algorithm for improving vehicle handling was proposed by applying right angle to the steering wheel,based on the nonlinear adaptive optimal control(NAOC).A nonlinear 4-DOF model was initially developed,then ...A control algorithm for improving vehicle handling was proposed by applying right angle to the steering wheel,based on the nonlinear adaptive optimal control(NAOC).A nonlinear 4-DOF model was initially developed,then it was simplified to a 2-DOF model with reasonable assumptions to design observer and optimal controllers.Then a simplified model was developed for steering system.The numerical simulations were carried out using vehicle parameters for standard maneuvers in dry and wet road conditions.Moreover,the hardware in the loop method was implemented to prove the controller ability in realistic conditions.Simulation results obviously show the effectiveness of NAOC on vehicle handling and reveal that the proposed controller can significantly improve vehicle handling during severe maneuvers.展开更多
In China,hot researches on shale oil were raised by the important breakthrough of shale oil in America.Obviously,the first important issue is the actual shale oil resource potential of China,and the selection of the k...In China,hot researches on shale oil were raised by the important breakthrough of shale oil in America.Obviously,the first important issue is the actual shale oil resource potential of China,and the selection of the key appraisement parameter is vital to the shale oil resource amount.Among the appraisement parameters,the oil content parameter(S1)is the key one,but the evaluation result is generally lower because of light hydrocarbon losing and heavy hydrocarbon handling.And the more important thing is that the light hydrocarbon with small molecular weight is more recoverable,and therefore its amount is important to the total shale oil yields.Based on pyrolysis experiments and the kinetic model of hydrocarbon generation,correction factors and a model of light hydrocarbon losing and heavy hydrocarbon handling were established.The results show that the correction factor of heavy hydrocarbon handling is 3.2,and that of light hydrocarbon losing is controlled by kerogen type,maturity and hydrocarbon generation environment(closed or open).展开更多
文摘Banana (Musa spp.) is a highly perishable fruit that requires special handling. In Eritrea, post-harvest handling practices are characterized to be poor and as a result, poor fruit quality and high post-harvest loss are common. Thus, the purpose of this study was to evaluate the effect of different post-harvest handling and ripening methods on quality and shelf-life of banana. A Complete Randomized Design (CRD) was used for evaluating a combination of two levels of post-harvest handling and four ripening methods in a factorial combination conducted in the laboratory of Horticulture at Hamelmalo Agricultural College. Peel colour change, physiological weight loss, pulp to peel ratio, total soluble solids (TSS), pulp pH, ripening period and shelf life were parameters studied. The results showed fruits treated with ripened tomato showed improved characteristics in all parameters compared to those treated with smoke from kerosene burning or mixed with moringa leaf. Similarly, fruits brought directly from the farm were better than those collected from the ripening room after passing the conventional post-harvest handling. Based on the results of this study, it can be concluded that ripening of banana with the help of tomato improves fruit quality and shelf life. Thus, it can be a safe and better alternative to smoking from kerosene burning. While moringa leaf has no potential as an alternative.
文摘A cross-sectional study was carried out to assess hygienic production and postharvest handling practices of raw camel milk in Degahbour district. The survey studies were based on a total of 120 (2 production systems * 2 rural kebele * 30 households) milk producers, which were selected from Degahbur district using stratified sampling technique. Data from the selected producers were collected using questionnaire survey and field observation. The results showed that the majority of the sampled household heads in pastoral (93.3%) and agro-pastoral (76.6%) production systems were illiterate. Moreover, none of the respondents in the study area had training on hygienic milk production and postharvest handling practices. The study result also indicated that none of the respondents in the study area washed the udder of milking camel before milking. Moreover, only 6.6% of pastoralists and 25% of agro-pastoralists wash their hands before milking. Equipment made of wooden materials are mainly used for milking, whereas, plastic jerry-cans were most commonly used for storage. About 45% of the pastoralists and 81.6% of the agro-pastoralists were cleaning milk vessels regularly;however, majority of the respondents both production systems were using water from non-tap sources for hygienic practices. Bosciaminimifolia, Acacia ethaica and Blanitesgalabra were the most commonly used plant species for smoking in the study area. Therefore, hygienic production and postharvest handling practices should be followed to improve the quality and suitability of camel milk for its intended use in the study area.
基金The research was supported by the National Science Foundation of China(Grant No.31971795)and Priority Academic Program Development of Jiangsu Higher Education Institutions(Grant No.PAPD-2018-87)The authors are grateful to the National Science Foundation of China.The first author thanks the China Scholarship Council(2017GXZ026592)for providing 36 months scholarship for studying in China.The first author would like to thank his mother and wife Sidra for their moral support。
文摘Mechanical damage induced by vibration during harvesting and post-harvest handling could decrease the quality,quantity,and shelf life of the fresh grape cluster.Usually,fresh grape clusters are harvested by gripping and cutting from the main rachis in the present robotic harvesting system,then transported towards the basket during post-harvest handling.However,serious cluster vibration and corresponding berry falling may occur during the robotic transportation of hanging grape clusters.Therefore,this study was designed to perform experimental and theoretical hanging force analysis to explore the vibration mechanism of hanging grape clusters during robotic transportation.A lead screw lathe with an attached linear actuator was used to investigate the effects of four different speeds(0.4,0.6,0.8,1.0 m/s)with four acceleration levels(6,8,10,12 m/s2)on the vibration of the hanging grape cluster.By the experiments,the peak hanging force of the grape cluster at the start,constant speed,and stop phase of the actuator was recorded using a single axis force sensor,and the cluster’s swing angle was measured with a digital camera.The experimental results showed a linear relationship between the swing angle and hanging force of the cluster at the start and stop phase of the actuator.The multi-stage cluster’s vibration during robotic transportation was observed,and the behavior of cycled damping after a sudden stop of the actuator was found.The simulated results of hanging force of grape cluster in damping phase were agreed with experimental results with R2 more than 0.90 at an optimum acceleration of 10 m/s2.To conclude,this research provides theoretical basics for understanding the complex vibration mechanism of the hanging cluster fruits during speedy robotic transportation operations with low-loss of berry drop both on industrial and farm levels.
基金Supported by Direktorat Riset dan Pengembangan(Directorate of Research and Development)Universitas Indonesia(NKB-690/UN2.RST/HKP.05.00/2022).
文摘The need to transport goods across countries and islands has resulted in a high demand for commercial vessels.Owing to such trends,shipyards must efficiently produce ships to reduce production costs.Layout and material flow are among the crucial aspects determining the efficiency of the production at a shipyard.This paper presents the initial design optimization of a shipyard layout using Nondominated Sorting Algorithm-Ⅱ(NSGA-Ⅱ)to find the optimal configuration of workstations in a shipyard layout.The proposed method focuses on simultaneously minimizing two material handling costs,namely work-based material handling and duration-based material handling.NSGA-Ⅱ determines the order of workstations in the shipyard layout.The semiflexible bay structure is then used in the workstation placement process from the sequence formed in NSGA-Ⅱ into a complete design.Considering that this study is a case of multiobjective optimization,the performance for both objectives at each iteration is presented in a 3D graph.Results indicate that after 500 iterations,the optimal configuration yields a work-based MHC of 163670.0 WBM-units and a duration-based MHC of 34750 DBM-units.Starting from a random solution,the efficiency of NSGA-Ⅱ demonstrates significant improvements,achieving a 50.19%reduction in work-based MHC and a 48.58%reduction in duration-based MHC.
基金supported by the National Key R&D Program of China(2022YFC3500405,2019YFC1712105)The National Science Foundation of China(82374075)+1 种基金The National Comprehensive Traditional Chinese Medicine Reform Demonstration Zone Science and Technology Collaborative Development Project(GZY-KJS-SD-2024-046)Taishan Scholar Youth Project of Shandong Province(tsqn202306188).
文摘Objective:Arrhythmia-induced cardiomyopathy(AIC)is a reversible dilated cardiomyopathy induced by rapid or irregular heartbeat.Acupuncture has a long history of use in the treatment of cardiac diseases,and Xinshu(BL15)is a key acupoint.However,the underlying mechanism of acupuncture at BL15 in the treatment of AIC has not yet been elucidated.Methods:AIC was induced in adult male Sprague-Dawley(SD)rats by continuous administration of acetylcholine(ACh)-CaCl2 and treatment with electroacupuncture(EA)at bilateral BL15.Echocardiography was used to evaluate cardiac function;the rotarod test for motor coordination and performance;hematoxylin and eosin(HE)staining for the morphology of ventricles;electrocardiogram for susceptibility,inducibility,and duration of atrial fibrillation(AF);and electrical and optical mapping in isolated rat hearts maintained by the Langendorff perfusion system for electrical conduction and intracellular handling,respectively.Reverse transcription quantitative polymerase chain reaction(RT-qPCR)and Western blotting were used to determine the levels of cardiac conduction and intracellular calcium-handling proteins in the ventricle.Results:The results showed that EA improved the ejection factor and morphological indices on echocardiography,restored motor coordination and performance,and alleviated ventricular dilation and AF onset.EA alleviates atrial conduction disorders,shortens APD80,and decreases calcium handling in rats with AIC.Cx43 was downregulated and CaMKII was upregulated,and both effects were reversed by EA treatment.Conclusion:Our study provides a novel AIC model with abnormal electrical propagation and calcium handling that can be protected by EA at BL15.This potential mechanism may be associated with the modulation of Cx43 and CaMKII expression.
文摘This paper introduces an intelligent garbage-handling trolley model based on an STM32 single chip microcomputer as the control core.The device is driven by four independent motors to achieve automatic tracking,automatic obstacle avoidance,and fixed-point docking.Using external execution structure to realize the car without the use of a mechanical arm,complete garbage collection,storage,and uninstall function.On this basis,the type of garbage is marked by color,and the color recognition sensor is applied to realize the type recognition after garbage collection and put into the corresponding unloading point,to realize its intelligent classification function.It can automatically complete the established task autonomously.
文摘Object detection in occluded environments remains a core challenge in computer vision(CV),especially in domains such as autonomous driving and robotics.While Convolutional Neural Network(CNN)-based twodimensional(2D)and three-dimensional(3D)object detection methods havemade significant progress,they often fall short under severe occlusion due to depth ambiguities in 2D imagery and the high cost and deployment limitations of 3D sensors such as Light Detection and Ranging(LiDAR).This paper presents a comparative review of recent 2D and 3D detection models,focusing on their occlusion-handling capabilities and the impact of sensor modalities such as stereo vision,Time-of-Flight(ToF)cameras,and LiDAR.In this context,we introduce FuDensityNet,our multimodal occlusion-aware detection framework that combines Red-Green-Blue(RGB)images and LiDAR data to enhance detection performance.As a forward-looking direction,we propose a monocular depth-estimation extension to FuDensityNet,aimed at replacing expensive 3D sensors with a more scalable CNN-based pipeline.Although this enhancement is not experimentally evaluated in this manuscript,we describe its conceptual design and potential for future implementation.
基金Supported by the Australian Research Council’s Discovery Project(Grant No.DP200100149)Taishan Scholars Program of Shandong Province(Grant No.tsqn202211062)Chinses Scholarship Council(Grant No.202006690005).
文摘The cooperative control of ride comfort and handling stability in automobile suspension systems presents a significant challenge in intelligent chassis system design.This complexity arises from the high degrees of freedom,diverse operating conditions,and inherent trade-offs between performance metrics in full-car suspension systems.In this paper,a novel switching control strategy is proposed to better balance ride comfort and handling stability for a full-car suspension system.The system integrates a ride comfort controller and an anti-rollover controller,guided by a new rollover risk assessment indicator that requires fewer state variables.First,a vehicle suspension simplification model approach is introduced,reducing the fourteen-degree-of-freedom full-car suspension model to three two-degree-of-freedom models:vertical,pitch and roll.Based on these simplified models,vertical,roll,and pitch controllers are designed,simplifying the controller design process for full-car suspension systems.The ride comfort controller is constructed using the modal energy method in conjunction with the simplified model controllers,while the roll controller functions as the anti-rollover controller.The proposed rollover risk assessment indicator serves as the switching criterion between handling stability and ride comfort control.Experimental results demonstrate that the proposed switching control strategy effectively adapts to various road conditions,enabling the semi-active variable damping suspension system to perform multi-modal switching.Compared to a well-tuned passive suspension,vertical,roll,and pitch accelerations are reduced by 14.13%,13.02%and 13.08%,respectively,significantly improving ride comfort.Additionally,the system effectively mitigates rollover risk,achieving reductions in roll angle,roll speed,and roll acceleration by 19.69%,16.40%,and 29.96%,respectively,thereby greatly enhancing vehicle safety.Overall,the proposed switching control strategy achieves a successful balance between ride comfort and handling stability,enhancing overall driving performance.
文摘Aiming at various faults in an air conditioning system,the fault characteristics are analyzed.The influence of the faults on the energy consumption and thermal comfort of the system are also discussed.The simulation results show that the measurement faults of the supply air temperature can lead to the increase in energy consumption.According to the fault characteristics,a data-driven method based on a neural network is presented to detect and diagnose the faults of air handling units.First,the historical data are selected to train the neural network so that it can recognize and predict the operation of the system.Then,the faults can be diagnosed by calculating the relative errors denoting the difference between the measuring values and the prediction outputs.Finally,the fault diagnosis strategy using the neural network is validated by using a simulator based on the TRNSYS platform.The results show that the neural network can diagnose different faults of the temperature,the flow rate and the pressure sensors in the air conditioning system.
文摘A DC to 5GHz series MEMS switch is designed and fabricated for wireless communication applications,and thermal effect and power handling of the series switch are discussed.The switch is made on glass substrate,and gold platinum contact is used to get a stable and little insert loss.From DC to 5GHz,0 6dB insertion loss,30dB isolation,and 30μs delay are demonstrated.Thermal effect of the switch is tested in 85℃ and -55℃ atmosphere separately.From DC to 4GHz,the insert loss of the switch increases 0 2dB in 85℃ and 0 4dB in -55℃,while the isolation holds the same value as that in room temperature.To measure the power handling capability of the switch,we applied a continuous RF power increasing from 10dBm to 35 1dBm with the step of 1 0dBm across the switch at 4GHz.The switch keeps working and shows a decrease of the insert loss for 0 1～0 6dB.The maximum continuous power handling (35 1dBm,about 3 24W) is higer than the reported value of shunt switch (about 420mW),which implies series switches have much better power handling capability.
基金The National Natural Science Foundation of China(No60503020)the National Basic Research Program of China (973Program) (No2002CB312000)+1 种基金the Natural Science Foundation of Jiangsu Province (NoBK2006094)the Science Research Foundation of China University of Mining and Technology
文摘To solve the problems that the exception handling code is hard to test and maintain and that it affects the robustness and reliability of software, a method for evaluating the exception handling of programs is presented. The exception propagation graph （EPG） that describes the large programs with exception handling constructs is proposed by simplifying the control flow graph and it is applied to a case to verify its validity. According to the EPG, the exception handling code that never executes is identified; the points that are the most critical to controlling exception propagation are found; and the irrational exception handling code is corrected. The constructing algorithm for the EPG is given; thus, this provides a basis for automatically constructing the EPG and automatically correcting the irrational exception handling code.
文摘Objectives: This paper examines the basic knowledge ofAIDS and HIV transmission through unsafe blood collec-tion and supply among rural Chinese doctors. It also ex-plores the accessibility of AIDS intervention methods inrural area. Methods: We did Case studies, held focus group discus-sions and provided questionnaires to all rural doctors inone township where the epidemic of HIV was known to bespread through blood collection and supply. Data were col-lected and analyzed with software EPI 6.0.Results: The effective response rate to the questionnairewas 100%. The results showed that more than 95% of in-formants gave correct answers to the questions about thesexual and blood-bourne transmission of HIV as well as itscontagiousness. Half of the participants were ignorant aboutmother to child transmission of HIV and did not know thatHIV couldn’t be transmitted by saliva, sweat, mosquito bites,sharing of bathtubs or toilets. More than 80% of infor-mants were opposed to blood selling and reportedly under-stood the objective of the blood organizers in their villages,knew the peak time of blood selling by the villagers, and ,were aware of the risks of diseases being spread throughblood. . 27.3% used disposable syringes ‘once in a while’,and 15.2% discarded or sold used disposable syringes.Conclusions: The authors assert that there are severe lurk-ing perils of iatrogenic cross infection in rural areas. Ruraldoctors urgently need formal training on prevention andtreatment of HIV infection. We believe that rural doctorsshould become the key force in AIDS prevention and con-trol in rural area.
基金supported in part by grants from the National Natural Science Foundation of China(31772475 31672307+1 种基金31401981 31372215)
文摘In some non-human primates, infants function as a social tool that can bridge relationships among group members. Infants are a desired commodity for group members, and mothers control access to them. The biological market theory suggests that grooming is widespread and represents a commodity that can be exchanged for infant handling. As a limited resource, however, the extent to which infants are interchanged between mothers(females with an infant) and non-mothers(potential handlers,females without an infant) remains unclear. In this study, we collected behavioral data to investigate the relationship between grooming and infant handling in free-ranging Tibetan macaques(Macaca thibetana)at Mt. Huangshan, China. Our results showed that females with infants received more grooming than females without infants. After her infant was handled,mother females received more grooming than they did during daily grooming interactions. However, with the increasing number of infants within the social group, both the grooming that mothers received and the grooming that non-mothers invested for handling infants decreased. We also found that non-mothers invested more time in grooming to gain access to younger infants than older infants. Our results provide evidence that infants are social commodities for both mother and non-mother females. Mothers use infants for obtain grooming and non-mothers use grooming to gain access to infants. The current study implies a bidirectional and complex interchange pattern between grooming and infant handling to compensate for the dyadic grooming disparity in non-human primates.
基金supported by National Natural Science Foundation of China (Grant No. 50675027)
文摘Compared with traditional mechanical seals,magnetic fluid seals have unique characters of high airtightness,minimal friction torque requirements,pollution-free and long life-span,widely used in vacuum robots.With the rapid development of Integrate Circuit（IC）,there is a stringent requirement for sealing wafer-handling robots when working in a vacuum environment.The parameters of magnetic fluid seals structure is very important in the vacuum robot design.This paper gives a magnetic fluid seal device for the robot.Firstly,the seal differential pressure formulas of magnetic fluid seal are deduced according to the theory of ferrohydrodynamics,which indicate that the magnetic field gradient in the sealing gap determines the seal capacity of magnetic fluid seal.Secondly,the magnetic analysis model of twin-shaft magnetic fluid seals structure is established.By analyzing the magnetic field distribution of dual magnetic fluid seal,the optimal value ranges of important parameters,including parameters of the permanent magnetic ring,the magnetic pole tooth,the outer shaft,the outer shaft sleeve and the axial relative position of two permanent magnetic rings,which affect the seal differential pressure,are obtained.A wafer-handling robot equipped with coaxial twin-shaft magnetic fluid rotary seals and bellows seal is devised and an optimized twin-shaft magnetic fluid seals experimental platform is built.Test result shows that when the speed of the two rotational shafts ranges from 0-500 r/min,the maximum burst pressure is about 0.24 MPa.Magnetic fluid rotary seals can provide satisfactory performance in the application of wafer-handling robot.The proposed coaxial twin-shaft magnetic fluid rotary seal provides the instruction to design high-speed vacuum robot.
基金Supported by National Basic Research Program of China(973 Program,Grant No.2011CB711200)National Science and Technology Support Program of China(Grant No.2015BAG17B00)National Natural Science Foundation of China(Grant No.51475333)
文摘For a distributed drive electric vehicle(DDEV)driven by four in-wheel motors,advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently,quickly and precisely.And direct yaw-moment control(DYC)has been widely studied and applied to vehicle stability control.Good vehicle handling performance:quick yaw rate transient response,small overshoot,high steady yaw rate gain,etc,is required by drivers under normal conditions,which is less concerned,however.Based on the hierarchical control methodology,a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed.The upper-loop control system consists of two parts:a state feedback controller,which aims to realize the ideal transient response of yaw rate,with a vehicle sideslip angle observer;and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain.Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors,the integrated time and absolute error(ITAE)function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix.Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method:yaw rate rising time is reduced,steady yaw rate gain is increased,vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced.The control system improves vehicle handling performance under normal conditions in both transient and steady response.State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.
文摘This paper presents a novel five degrees of freedom (DOF) two-wheeled robotic machine (TWRM) that delivers solutions for both industrial and service robotic applications by enlarging the vehicle′s workspace and increasing its flexibility. Designing a two-wheeled robot with five degrees of freedom creates a high challenge for the control, therefore the modelling and design of such robot should be precise with a uniform distribution of mass over the robot and the actuators. By employing the Lagrangian modelling approach, the TWRM′s mathematical model is derived and simulated in Matlab/Simulink?. For stabilizing the system′s highly nonlinear model, two control approaches were developed and implemented: proportional-integral-derivative (PID) and fuzzy logic control (FLC) strategies. Considering multiple scenarios with different initial conditions, the proposed control strategies′ performance has been assessed.
文摘A control algorithm for improving vehicle handling was proposed by applying right angle to the steering wheel,based on the nonlinear adaptive optimal control(NAOC).A nonlinear 4-DOF model was initially developed,then it was simplified to a 2-DOF model with reasonable assumptions to design observer and optimal controllers.Then a simplified model was developed for steering system.The numerical simulations were carried out using vehicle parameters for standard maneuvers in dry and wet road conditions.Moreover,the hardware in the loop method was implemented to prove the controller ability in realistic conditions.Simulation results obviously show the effectiveness of NAOC on vehicle handling and reveal that the proposed controller can significantly improve vehicle handling during severe maneuvers.
基金supported by"the Fundamental Research Funds for the Central Universities"(14CX05017A)the Natural Science Foundation of China(41330313)+1 种基金Program for New Century Excellent Talents in Heilongjiang Provincial University(1252-NCET-012)CNPC Innovation Foundation(2011D-5006-0101)
文摘In China,hot researches on shale oil were raised by the important breakthrough of shale oil in America.Obviously,the first important issue is the actual shale oil resource potential of China,and the selection of the key appraisement parameter is vital to the shale oil resource amount.Among the appraisement parameters,the oil content parameter(S1)is the key one,but the evaluation result is generally lower because of light hydrocarbon losing and heavy hydrocarbon handling.And the more important thing is that the light hydrocarbon with small molecular weight is more recoverable,and therefore its amount is important to the total shale oil yields.Based on pyrolysis experiments and the kinetic model of hydrocarbon generation,correction factors and a model of light hydrocarbon losing and heavy hydrocarbon handling were established.The results show that the correction factor of heavy hydrocarbon handling is 3.2,and that of light hydrocarbon losing is controlled by kerogen type,maturity and hydrocarbon generation environment(closed or open).
