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To improve the overall mechanization level of rapeseed production in China, especially in some hilly regions where ground machinery cannot enter the fields or can only enter with very low economic benefits, a special aerial seeding system for rapeseed based on a miniature air-assisted centralized metering device was designed and tested in this study. Unlike existing commercial aerial seeding systems, the proposed seed meter was a miniaturized version derived from the traditional air-feeding seed meter on ground planters. The new version contained a redesigned seed feeding component to overcome problems of serious air backflow to the seed box and difficult seed feeding after miniaturization. Three groups of experiments were designed and conducted to optimize the parameters of the seed meter and test its performance. Results from the orthogonal experiment showed that the seed feeding component performed best when the seed layer thickness was 45 mm, the rotational speed of the gear disc was 45 r/min, and the airflow pressure was 2450 Pa. Results from the static workbench test showed that the designed seeding system had a maximum average total sowing efficiency of 537.17 g/min, with the maximum values of the stability variation coefficient of total seeding rate (seven ports) and the consistency variation coefficient between each port was 2.37% and 4.89%, respectively. Field tests further proved that the designed aerial seeding system could work stably, uniformly, and efficiently, so that the agronomic requirements of rape crop planting could be well met.

The main objective of this study was to design a pneumatic disk with four-rows for planting rapeseed and to investigate its performance under several rotating speeds and vacuum pressure values. The effects of rotating speeds, vacuum pressure and rows on seed sucking and retaining were inspected. Six rotating speeds (5 r/min, 10 r/min, 15 r/min, 20 r/min, 25 r/min and 30 r/min) incorporated with the application of vacuum pressure were employed for detecting the optimum vacuum amount that was sufficient for seed sucking under each speed. These values of vacuum were found to be 1.1 kPa, 1.25 kPa, 1.35 kPa, 1.65 kPa, 1.8 kPa and 2.0 kPa, respectively.Moreover, a regression model was developed for predicting of vacuum pressure that corresponds with each rotating speed. Based on seed mass analysis, statistical differences were found at 5% significance under the influence of speeds and negative pressure and existed also between and within rows according to Duncan's Test.The highest seed mass means of 3.17 g and 3.96 g were obtained by row 1 under the effects of speed and vacuum pressure, respectively, while the lowest means of 2.79 g and 3.05 g were attained by row 4. Due to the influence of rows, important differences were occurred between row 1 (closer to the center of rotation) and row 4 (farther one), particularly under high speeds (25 r/min and 30 r/min).Results concluded that, pneumatic disk with multiple-rows could be satisfactorily used for seed sowing with a little variation in seed amount between rows without any seed damage. The rows of hole farther from plate center of rotation were obviously influenced by angular velocity and vacuum amount rather than the closer ones.

The potential of near infrared (NIR) spectroscopy combined with chemometrics methods was studied to rapidly detect intramuscular fat (IMF) content in pork. Near infrared diffuse reflectance spectra were recorded both with an FT-NIR and a USB4000 spectrometer. The data analysis was compared on different sample preparation, spectral range and spectra pretreatment. According to calibration statistics, best calibration for IMF showed R 2 cal of 0.94, R 2 val of 0.92, RMSEC of 0.233, RMSEP of 0.462 and RPD of 2.29. The prediction of IMF content for minced samples was more accurate than that for intact samples. The spectra obtained using FT-NIR contained much information correlating to the IMF content than the Vis-NIR spectra of USB4000. The results showed that NIR spectroscopy technique can be used to determine the IMF content in pork as a rapid, convenient, and feasible analysis tool. ARTICLE HISTORY