Development of a gaseous and solid-state hybrid system for stationary hydrogen energy storage

Hydrogen can serve as a carrier to store renewable energy in large scale.However,hydrogen storage still remains a challenge in the current stage.It is difficult to meet the technical requirements applying the conventional storage of compressed gaseous hydrogen in high-pressure tanks or the solid-state storage of hydrogen in suitable materials.In the present work,a gaseous and solid-state(G-S)hybrid hydrogen storage system with a low working pressure below 5 MPa for a 10 kW hydrogen energy storage experiment platform is developed and validated.A Ti-Mn type hydrogen storage alloy with an effective hydrogen capacity of 1.7 wt%was prepared for the G-S hybrid hydrogen storage system.The G-S hybrid hydrogen storage tank has a high volumetric hydrogen storage density of 40.07 kg H_(2)m^(-3) and stores hydrogen under pressure below5 MPa.It can readily release enough hydrogen at a temperature as low as-15C when the FC system is not fully activated and hot water is not available.The energy storage efficiency of this G-S hybrid hydrogen storage system is calculated to be 86.4%-95.9%when it is combined with an FC system.This work provides a method on how to design a G-S hydrogen storage system based on practical demands and demonstrates that the G-S hybrid hydrogen storage is a promising method for stationary hydrogen storage application.

Effect of carbon coating on electrochemical properties of AB_(3.5)-type La-Y-Ni-based hydrogen storage alloys

The superlattice La-Y-Ni-based hydrogen storage alloys have high discharge capacity and are easy to prepare.However,there is still a gap in commercial applications because of the severe corrosion of the alloys in electrolyte and poor high-rate dischargeability(HRD).Therefore,(LaSmY)(NiMnAl)_(3.5) alloy was prepared by magnetic levitation induction melting,and then the alloy was coated with different contents(0.1 wt%-1.0 wt%) of nano-carbons by low-temperature sintering with sucrose as the carbon source in this work.The results show that the cyclic stability and HRD of the alloy first increase and then decrease with the increase of carbon contents.The kinetic results show that the electrocatalytic activity and conductivity of the alloy electrodes can be enhanced by carbon coating.The electrochemical properties of the alloy are the best when the carbon coating content is 0.3 wt%.Compared with the uncoated alloy,the maximum discharge capacity(C_(max)) improves from 354.5 to 359.0 mAh/g,the capacity retention rate after 300 cycles(S_(300)) enhances from 73.15% to 80.01%,and the HRD_(1200) of the alloy enhances from 74.39% to 74.39%.

Influence of the inner tilt angle on downwash airflow field of multi-rotor UAV based on wireless wind speed acquisition system

The downwash airflow field is an important factor influencing the spraying performance of plant protection UAV,and the structural design of rotors directly affects the characteristics of the downwash airflow field.Therefore,in this study,three-dimensional models of a six-rotor UAV with various inner tilt angles were established to simulate and analyze the influence of the inner tilt angle on the downwash airflow field based on the Reynolds average NS equation,RNG k-εturbulence model,etc..On this basis,a wireless wind speed acquisition system using the TCP server was developed to carry out the test through the marked points with real-time detection.The simulation results show that,the variation of inner tilt angles of the six-rotor UAV did not cause significant difference in the time dimension of the downwash airflow field,and with the change of the inner tilt angle from 0°to 8°,the distribution of downwash airflow field tended to obliquely shrink towards the central axis direction,and the amplitude of linear attenuation of airflow speed was also increased,which the difference of attenuation amplitude was 1 m/s.Besides,under the different inner tilt angle,the airflow velocity in“lead in area”was significantly greater than that in the“lead out area”,and the difference of air velocity distribution in space would affect the uniformity of droplet deposition.Through the calibration test,the measurement accuracy error of the developed system was lower than 0.3 m/s,and the adjusted R2 of the calibration fitting equation was higher than 0.99.The test and simulation values at test points from 0.2-2.3 m below the rotors exhibit the same variation trend,and the average relative error at the height of 1.1-2.3 m below the rotors and 0.2-0.8 m near the ground was within 10%and 20%,respectively.The simulation and test results were highly reliable,which could provide basis and reference for the design and optimization of plant protection drones.

A promising trend for field information collection:An air-ground multi-sensor monitoring system

Timely identifying and quantifying significant spatial and temporal variability in agricultural field has been a crucial factor for improving agricultural production and management.This paper focuses on the mainstream techniques and applications can be adopted to improve the field information collection method.In this paper,the development of wireless sensor networks(WSNs)and remote sensing(RS)technology were reviewed,especially the micro unmanned aerial vehicle(mUAV)-based WSNs and mUAV-based RS by analyzing its applications in field information collection,and pointed out its existing benefits and limitations.A system encompassed multiple technique approaches was proposed in this paper which is called air-ground multi-sensor monitoring system.With the diversification methods of in-field information collection and the improvement of detection precision,an infield information collection system will play an important role in controlling the farming operations of mechanized agriculture and optimizing the management of agricultural machinery group.In the future,the combination of mUAV,WSNs and RS for crop and soil monitoring will become a powerful tool to obtain field information,increase production,optimize the overall farming practices and input of resources and provide comprehensive reference for the study of soil-crops-machine relationships.

Review of electro-hydraulic hitch system control method of automated tractors

The automatic and intelligent degree of tractor hitch system determines the operations quality,efficiency,tractor power output and energy consumption,and automatic control of electro-hydraulic hitch is one of the key technical problems in the realization of automated tractor.In this study,the adjustment methods and characteristics of electro-hydraulic hitch system were summarized.The development of electro-hydraulic hitch control technologies was elaborated and analyzed from both the electro-hydraulic control strategy and slip control strategy perspectives.The implementation methods and control characteristics were discussed.A new idea for the development of automated tractor was put forward that integrating cutting-edge technologies such as big data,fusion control and artificial intelligence.In addition,based on the precise and efficient control of electro-hydraulic hitch system,a high reliability of the control system of the tractor with intelligent application of the control algorithm was obtained.The results can provide a reference for the precise operation of automated tractors under the big data in agriculture.

Design and performance analysis of indoor calibration device for the forcemeasuring system of the tractor three-point hitch

The real-time monitoring of the load in farming by the sensor installed on the tractor's three-point hitch can effectively improve the farming efficiency and force-position combined control,reduce the compaction risk of the wheel on the soil and reduce the fuel consumption in farming process.However,the measurement and quantification of the loads on the three-point hitch have some problems remaining unresolved:testing the accuracy and reliability of a load measuring system is hard when the tractor works in a field,the mathematical model of spatial forces usually lacks a practical and effective validation,and the calibration process of the measurement system is inconvenient and incomplete while easily causing a low accuracy.Specifically,this paper builds a new spatial-force mathematical model based on the geometry of a three-point hitch.To eliminate the discrepancy of the geometric model with the actual structure and to refine the mathematical model,a calibration process is conducted by developing a calibration bench,which is equipped with a data acquisition system and a multi-parameter monitoring interface.The three-point hitch installed on this calibration bench is subject to steady-state loading.The loading force,angle of the lower drawbar,and three-component forces(three shaft pin sensors’forces)of the three-point hitch are well measured.With applying for the measured data to calibrate the theoretical mathematic model eventually derives the resultant force from all the three-component forces,a dynamical loading bench was developed to test the calculated resultant force for the three-point hitch during the sinusoidal and randomly variant dynamical loadings tests.A hitch force measurement system is also developed to collect real-time data and calculate the resultant force of measured three-component forces through the calibrated mathematical model.The results of the dynamical loading tests show that the average relative error MRE=1.09%with an average force measurement time delay beingΔt=0.5 s,the root mean square error RMSE=59.3 N,and the coefficient of determination R2=0.9903.As observed,the shape and the trend of the generated resultant force curve are basically the dynamical loading force.The dynamical loading test proves the high efficacy and reliability of the proposed indoor calibration method for calculating the load based on the three-component forces as measured on the three-point hitch.Besides,the preliminary study of the proposed method on the hitch load provides great potential to improve the indoor six-component measurement and quantification of both the force and momentum acting on the three-point hitch.