Effects of simulated submerged and rigid vegetation and grain roughness on hydraulic resistance to simulated overland flow

Better understanding of the role of vegetation and soil on hydraulic resistance of overland flow requires quantitative partition of their interaction. In this paper, a total of 144 hydraulic flume experiments were carried out to investigate the hydraulic characteristics of overland flow. Results show that hydraulic resistance is negatively correlated with Reynolds number on non-simulated vegetated slopes, while positively on vegetated slopes. The law of composite resistance agrees with the dominant resistance, depending on simulated vegetation stem,surface roughness, and discharge. Surface roughness has greater influence on overland flow resistance than vegetation stem when unit discharge is lower than the low-limited critical discharge, while vegetation has a more obvious influence when unit discharge is higher than the upper-limited critical discharge. Combined effects of simulated vegetation and surface roughness are unequal to the sum of the individual effects through t-test, implying the limitation of using linear superposition principle in calculating overland flow resistances under combined effect of roughness elements.

Study on Character of Micro-Canal Deposit and Its Significance in Petroleum Geology——Case study of Tuo-147-well in north zone of Dongying depression

Exploration on reservoir of glutenite segment in steep slope zone of half graben-like basin is one of the hot spot targets at present and in the future for new reservoirs; And the study of sediment character of sandy-conglomerate bodies is the keystone and also the difficult problem. Taking Tuo-147-well area in north zone of Dongying depression as an example, the micro-canal sedimentation was researched. The result shows that many micro-canals exist at the end of slope grain-flow in steep slope zone of half graben-like basin; The micro-canals grow at the end of subaqueous grain-flow deposited bodies of 3rd member of the Shahejie formation. The main condition of micro-canal formation is the slope angle less than 18° and a long suitable sedimentary slope. These micro-canals may communicate the reservoir of glutenite segment in steep slope zone and the hydrocarbon stratum as a bridge role. Therefore, it is significant in theory and practice for discovering a series of micro-canals at the end of slope grain-flow in steep slope zone of half graben-like basin.

AN OBJECT ORIENTED MODEL SCHEDULING FOR MEDIA-SOC

This paper proposes an object oriented model scheduling for parallel computing in media MultiProcessors System on Chip(MPSoC).Firstly,the Coarse Grain Data Flow Graph(CGDFG) parallel programming model is used in this approach.Secondly,this approach has the feature of unified abstraction for software objects implementing in processor and hardware objects implementing in ASICs,easy for mapping CGDFG programming on MPSoC.This approach cuts down the kernel overhead and reduces the code size effectively.The principle of the oriented object model,the method of scheduling,and how to map a parallel programming through CGDFG to the MPSoC are analyzed in this approach.This approach also compares the code size and execution cycles with conventional control flow scheduling,and presents respective management overhead for one application in me-dia-SoC.

Development and optimization of a novel grain flow sensor based on PVDF piezoelectric film

A novel grain flow sensor consists of an impact plate and a PVDF(Polyvinylidene Fluoride)piezoelectric film was developed in this research.The kinetic model of the grain flow sensor was built to analyze the steady and transient vibration disturbances which had a significant influence on performance of the sensor,and the results showed that damping ratio of the sensor was the key factor to improve accuracy of the sensor.To maximize damping ratio of the sensor,the thickness of the impact plate and damping material were optimized according to a loss factor model of the free damping structure.The optimized results indicated the most appropriate thickness ratio of damping material and the impact plate was 6.A test rig equipped with the novel grain flow sensor and weight sensors which could simulate field situations was built to investigate the performance of the sensor,on which test experiments under different feed flows were conducted.The results showed that the maximum error of the sensor was 3.02%and the mean error was 2.15%,which revealed that the novel grain flow sensor could be used to measure grain flow.Comparing with conventional grain flow sensors,the novel grain flow sensor has the features of high accuracy,simple structure and flexible signal processing methods.

Proportional distribution method for estimating actual grain flow under combine harvester dynamics

The yield monitors use a constant delay time to match the grain flow with location.Therefore,mixing and smoothing effects on the grain flow are neglected.Although constant time delay compensates for time mismatch,actual grain flow at a combine harvester head is not equal to the grain flow measured by a sensor due to the dynamics effects.In order to eliminate the dynamics effects,a new method for estimating actual grain flow,called proportional distribution(PD),is proposed.This method assumes that actual grain flow is directly proportional to the feedrate.Based on this assumption,the actual grain flow results from redistributing accumulated grain mass over a certain time according to the profile of the feedrate.The PD can avoid the dynamics effects because the feedrate is measured at a combine harvester’s head.Compared with constant time delay,the proposed method can effectively estimate actual grain flow and be applied to improve the accuracy of yield maps.

Grain flow rate sensing for a 55 kW full-feed type multi-purpose combine

Real time sensing of crop yield is critical for a successful implementation of precision agriculture.Yield monitoring system is an optional component of a 55 kW multi-purpose combine harvester,developed in Korea,for both domestic and global markets,especially Asian countries where field sizes are relatively small.The aim of the present study was to fabricate and evaluate the performance of a grain flow sensor suitable to the mid-sized full-feed type combine for rice,soybean,and barley.Firstly,commercially available non-contact type sensing modules(optical,ultrasonic,laser,and microwave modules)were chosen for alternative candidates,to be further tested in a laboratory bench.Through the laboratory tests,the ultrasonic module was selected as a potential approach and the performance was improved by increasing the number of modules and their layout.Finally,the improved grain flow sensor was evaluated during field harvesting operation.Field tests with the improved grain flow sensor showed a good potential for rice(R^(2)=0.85,RMSE=126.14 g/s),soybean(R^(2)=0.78,RMSE=43.87 g/s),and barley(R^(2)=0.83,RMSE=37.39 g/s).Further research would be necessary for improvement and commercialization,through various signal processing and field tests under different field and crop conditions.

Influence of vibration on the grain flow sensor during the harvest and the difference elimination method

The grain yield data collected by the intelligent yield measurement system of the combine harvester is generated into a field plot yield distribution map,which is of great significance for guiding agricultural production.However,in the process of drawing the yield map,the combine harvester is affected by vibration during operation and the generated error data in the process of collecting data which will cause the drawing results to be inaccurate.This study researched two factors that cause errors,then,the influence of vibration interference on the measurement signal was eliminated by filtering,vibration isolation,and designing a double-plates differential grain flow sensor.Three methods were taken to eliminate random errors,gross errors and systematic errors,including using the arithmetic average value to replace the true value,the 3σcriterion,and removing the filling time data and the delaying time data.Finally,the grain yield distribution map was obtained through Matlab and Excel.The results showed that the interference frequency above 50 Hz could be eliminated by filtering,but it was difficult to filter the low-frequency signal which was close to the grain impact frequency.The vibration amplitude was reduced to 14.29%by adding a vibration isolation plate,and the SNR was increased from−4.67 dB to 29.21 dB by combining low-pass filtering and damping vibration isolation.When the grain feeding rate was 2 kg/s,the natural vibration amplitude of the sensor after difference was about 0.02 V and evenly distributed around the zero voltage 0.2 V.The influence of positive and negative offset on the average value of grain impact signal could be ignored,and the signal-to-noise ratio was increased from 29.21 dB to 62.49 dB.The results of field experiments showed that the yield map drawn can clearly display the yield value of the harvest area,which is used to guide agricultural production.