General properties of polymers

2022 ◽  
pp. 19-48
Author(s):  
George Youssef
Keyword(s):  
1990 ◽  
Vol 88 (2) ◽  
pp. 233-250 ◽  
Author(s):  
Detlev Buchholz ◽  
Claudio D'Antoni ◽  
Roberto Longo

2021 ◽  
Vol 11 (16) ◽  
pp. 7223
Author(s):  
Dengyu Xiong ◽  
Mingliang Wu ◽  
Wei Xie ◽  
Rong Liu ◽  
Haifeng Luo

To address the problems of high damage rate, low seeding accuracy, and poor seeding generally in the seeding process, a general-purpose seeding device was designed in this study based on the principle of mechanical pneumatic combined seeding. The air-blowing-type cleaning and seed unloading of the device laid the conditions for precise seeding and flexible seeding. In addition, single-factor experiments were performed on seeds (e.g., soybeans, corn, and rape-seeds) with different particle sizes and shapes to verify the general properties of the seed metering device. A multi-factor response surface optimization experiment was performed by applying soybean seeds as the test object to achieve the optimal performance parameters of the seed metering device. At a seed-clearing air velocity of 16.7 m/s, a seed feeding drum speed of 13.7 r/min, and a hole cone angle of 35.6°, corresponding to the optimal performance index, the qualified index, the replay index, and the missed index reached 97.94%, 0.03%, and 2.03%, respectively. The verification test results are consistent with the optimized ones. As indicated from the results, the seed metering device exhibits good general properties, low damage rate, great precision, and high efficiency; it is capable of meeting general seeding operations of different crop seeds and technically supporting for the reliability and versatility of the seeder.


1984 ◽  
Vol 7 (3) ◽  
pp. 359-365
Author(s):  
Dymiter Skordev

The paper presents an abstract tool for describing general properties of programs. Iterative combinatory space approach makes possible to transfer recursion – theoretical methods onto logical system which is constructed in this paper.


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