Optimization of Parameters and Operating Modes of Disc Sowing Device According to Seeding Uniformity Criterion

Introduction. When cultivating agricultural crops, it is necessary to take into account the plants’ need for moisture, nutrients, location by area of nutrition, determining illumination, etc. Taking into account the biological characteristics of crops, various methods of sowing are used to create favorable conditions for plant growth and development. An important condition for sowing is the uniform arrangement of seeds along the sulcus, especially in the cultivation of testes of small-seeded cultures. A key role in the uniformity of seeding is provided by the design parameters and kinematic operating conditions of the sowing device. Materials and Methods. To determine the optimal parameters and operating modes of the disk sowing device, methods of factor experiment and multi-criteria optimization were used. Results. Mathematical models of the technological process of sowing seeds were obtained based of experimental studies. Conclusions. To ensure the improvement of the seeding quality of small seeds, the design parameters of the experimental seeder: х4 – is the diameter of the cell; х5 – the number of cells on the disk, will tend to the maximum values. The optimum circumferential speed of the sowing disk should be in the range from 0.127 to 0.192 m/s, and the speed of the machine’s movement is no more than 2 m/s.

Breaking symmetries

A well-known result by Palamidessi tells us that πmix(the π-calculus with mixed choice) is more expressive than πsep(its subset with only separate choice). The proof of this result analyses their different expressive power concerning leader election in symmetric networks. Later on, Gorla offered an arguably simpler proof that, instead of leader election in symmetric networks, employed the reducibility of ‘incestual’ processes (mixed choices that include both enabled senders and receivers for the same channel) when running two copies in parallel. In both proofs, the role ofbreaking (initial) symmetriesis more or less apparent. In this paper, we shed more light on this role by re-proving the above result – based on a proper formalization of what it means to break symmetries – without referring to another problem domain like leader election.Both Palamidessi and Gorla rephrased their results by stating that there is no uniform and reasonable encoding from πmixinto πsep. We indicate how their proofs can be adapted and exhibit the consequences of varying notions of uniformity and reasonableness. In each case, the ability to break initial symmetries turns out to be essential. Moreover, by abandoning the uniformity criterion, we show that there indeed is a reasonable encoding. We emphasize its underlying principle, which highlights the difference between breaking symmetries locally instead of globally.

A Study on the Optimal Design of Heating Chamber in Sputtering Process for Large-Sized LCD Panel Manufacturing

A thermal model was constructed to simulate the combined heat transfer phenomena, including thermal radiation in the heating chamber, during the sputtering process. The changes in thermal characteristics when thermal radiation occurred within the chamber system were analyzed using CFD (Computational Fluid Dynamics) method. The research emphasis in this paper was to explore the temperature distribution on the large glass panel. In order to achieve the temperature uniformity criterion (±15°C), the chamber design was improved to prevent a significant difference between temperature distributions. Several design factors were made to observe the effect on temperature distribution. After optimizing the chamber structure, the IR heater settings were in the end determined to meet the standards of three different sputtering circumstances.