Minimum projection uniformity criterion and its application

2006 ◽  
Vol 76 (6) ◽  
pp. 634-640 ◽  
Author(s):  
Shangli Zhang ◽  
Hong Qin
Keyword(s):  
Minimum Projection Uniformity ◽  
Uniformity Criterion

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

2018 ◽  
Vol 28 (3) ◽  
pp. 379-388
Author(s):  
Vladimir A. Ovchinnikov ◽  
Mikhail N. Chatkin ◽  
Alena V. Ovchinnikova
Keyword(s):  
Experimental Studies ◽  
Operating Conditions ◽  
Design Parameters ◽  
Optimal Parameters ◽  
Plant Growth And Development ◽  
Important Condition ◽  
Operating Modes ◽  
Favorable Conditions ◽  
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.

Search for structure-forming components in molecular crystals of binary compounds: a topological approach

2002 ◽  
Vol 217 (3) ◽  
Author(s):  
E. V. Peresypkina ◽  
V. A. Blatov
Keyword(s):  
Crystal Structures ◽  
Molecular Interactions ◽  
Molecular Crystal ◽  
Molecular Crystals ◽  
Topological Approach ◽  
Binary Compounds ◽  
Uniformity Criterion

AbstractMolecular crystal structures of 81 polymorphs of binary compounds are investigated with the method of coordination sequences and with the uniformity criterion for atomic sublattices. It is shown that using these tools one can estimate semi-quantitatively the relative force of inter-molecular interactions and to find so-called structure-forming lattice,

Structure-forming components in crystals of ternary and quaternary 3d-metal complex fluorides

2003 ◽  
Vol 59 (3) ◽  
pp. 361-377 ◽  
Author(s):  
E. V. Peresypkina ◽  
V. A. Blatov
Keyword(s):  
Crystal Structures ◽  
Essential Role ◽  
Complex Ions ◽  
Polymorphic Transitions ◽  
Stable Periodic ◽  
Quaternary Complex ◽  
Periodic Frameworks ◽  
Uniformity Criterion ◽  
Crystallochemical Analysis ◽  
Complex Fluorides

Crystallochemical analysis and classification were performed for 139 ternary and quaternary complex fluorides with the general formula M1 n M2 m M3F6, belonging to 33 structure types. Using coordination sequences and the uniformity criterion the structure-forming ionic sublattices or their combinations were found, which are responsible for the formation of stable periodic frameworks. Analysis of structure-forming motifs allows the interpretation of the crystal structures of complex fluorides as close packings of F ions with M1, M2 and M3 cations, partially occupying tetrahedral and octahedral voids, or as the packings of [M3F6] complex ions with M1 and M2 countercations in the voids. Cationic sublattices are noted to play an essential role, while forming crystal structures of complex fluorides. Relationships between the composition of structure-forming sublattices, the composition of compounds, and the size and charge of ions belonging to the sublattices were analysed under normal conditions, with thermal and high-pressure polymorphic transitions. Rules were formulated to predict the crystal structures of complex fluorides with a given chemical composition.

Topological analysis of ionic packings in crystal structures of inorganic sulfides: the method of coordination sequences

2001 ◽  
Vol 216 (3) ◽  
Author(s):  
V. A. Blatov
Keyword(s):  
Computer Program ◽  
Crystal Structures ◽  
Topological Analysis ◽  
Close Packing ◽  
The Third ◽  
Uniformity Criterion

AbstractUsing the concept of coordination sequences and the uniformity criterion the method of topological analysis of atomic packings and of their classification at any degree of metric distortions is implemented in the computer program IsoTest. The criterion is based on the search for packings topologically similar, but not equal to close packings. The topological analysis of ionic sublattices was employed for the crystal structures of 781 inorganic sulfides. It was shown that no less than in the third of cases the sulfides are constructed on the basis of a distorted close packing, and such packings are constructed with sufficiently large cations, as a rule. The examples of forming close packings by complex thioanions contained in a number of thiosalts were drawn.

Sign in / Sign up

Export Citation Format

Share Document