Friction Coefficient Calibration of Sunflower Seeds for Discrete Element Modeling Simulation

Sunflower(Helianthus annuus L.)is one of the four major oil crops in the world and has high economic value.However,the lack of discrete element method(DEM)models and parameters for sunflower seeds hinders the application of DEM for computer simulation in the key working processes of sunflower seed sowing and harvesting.The present study was conducted on two varieties of sunflower,and the DEM model of sunflower seeds was established by using 3D scanning technology based on the distribution of triaxial dimensions and volumes of the geometric model of sunflower seeds.Similarly,the physical characteristics parameters of sunflower seeds were determined by physical tests and the simulation parameters were screened for significance based on the Plackett-Burman test.Our results show that the coefficient of static friction between sunflower seeds and the coefficient of rolling friction have significant effects on the repose angle of the simulation test.Furthermore,the optimal range of the significance parameters was further determined by the steepest climb test,and the second-order regression model of the significance parameters and the repose angle was obtained according to the Box-Behnken design test and Response Surface Methodology(RSM),with the repose angle measured by the physical test as the optimized target value to obtain the optimal parameter combination.Finally,a two-sample t-test for the repose angle of the physical test and the repose angle of the simulation test yielded P>0.05.Our results confirms that the repose angle obtained from simulation is not significantly different from the physical test value,and the relative errors between the repose angle of the simulation test and the physical test are 1.43%and 0.40%,respectively,for the optimal combination of parameters.Based on these results it can be concluded that the optimal parameters obtained from the calibration can be used for DEM simulation experiments related to the sunflower seed sowing and harvesting process.

Profiling and geographical distribution of seed oil content of sunflower in Ukraine

The sunflower has the potential to be a highly competitive crop owing to its diversity market and the valuable oil it produces.Nevertheless,the amount of sunflower seed oil-a key factor for the crushing industry-is affected by genotype and environment,which sometimes is difficult to predict.The paper analyzes the theoretical principles of sunflower growth in Ukraine,highlights the current trends in the sowing of this crop,the influence of climatic factors of the environment on the prospects of the oilseed sunflower yield.The results of the research are presented for 3 years(2014-2016),during the authors conducted a grain quality observatory at the regional level,taking into account the climatic conditions of sunflower growth in different natural zones of Ukraine(from 45
to 51
north latitude and from 22
to 37
east longitude).Additionally,the research includes the coefficient of significance of the deviation from long-term climatic indicators,which makes it possible to forecast sunflower yield in the future.The analyzed data was obtained from the commercial fields with a minimum area of 40 ha in all Ukrainian regions except Crimea peninsula,Donetsk and Luhansk regions.The results obtained in research show the great diversity of oil content index as per both latitude and longitude meaning.If we consider the entire country,this survey shows that the seed oil content can change dramatically from year to year:e.g.47.5%in one year versus 45.7%in another year.Regionally,these changes have a completely different dynamic with a gradual decrease in seed oil content in the southern part of the country.The main goal of the research was to identify the best sunflower growing areas in Ukraine according to the oil content index.

Multiparameter collaborative optimization of the vibrating screen based on the behavior of oil sunflower seed penetrating screen holes

The behavior of oil sunflower seeds penetrating screen holes is an important factor that affects the screening performance of oil sunflower seeds.In this study,a double-deck reverse-motion vibrating screening device for oil sunflower seed screening was designed.The force condition and motion law of the oil sunflower seeds on the screen surface were analyzed.This study compared the effect of particle filling amount of discrete element model of oil sunflower seeds on the simulation effects.The screening process was numerically simulated using the coupled Discrete Element Method and Multibody Dynamics(DEM-MBD)technique with the screening percentage of oil sunflower seeds as the index.The influence of the operating parameters of the vibrating screen on the screening effect was analyzed using a multiparameter collaborative optimization scheme.The results of this study can provide a reference for the numerical simulation of crop screening behavior and the development of screening devices.

The preparation,characterization, and catalytic performance of porous fibrous LaFeO3 perovskite made from a sunflower seed shell template

LaFe03 perovskite with a porous fibrous structure was successfully synthesized using a sunflower seed shell as a template.To investigate the effects of this template,a sample was prepared without a template via the same procedure.Through various characterization techniques,such as X-ray diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,N2 adsorption-desorption analysis,X-ray photoelectron spectroscopy,oxygen temperature programed desorption,and hydrogen temperature programed reduction,the physiochemical properties of the samples were investigated.The results showed that the sample made with a template had a larger surface area and a larger amount of adsorbed oxygen,which further illustrated that the sunflower seed shell template had a significant impact on the physiochemical properties of the samples.Furthermore,we explored the catalytic activity for nitric oxide(NO)oxidation,and studied the factors affecting it,which highlighted its potential application in automobile exhausts.