scholarly journals Theoretical Study and Analysis of a Device for Pickling and Moving Bulk Materials

2021 ◽  
pp. 21-24
Author(s):  
◽  
N.M. Semashkin ◽  
V.A. Zlobin ◽  
E.V. Minibaeva ◽  
A.M. Isaeva ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Lagrange Equation ◽  
Cylindrical Body ◽  
Geometric Parameters ◽  
Theoretical Studies ◽  
Bulk Materials ◽  
Inner Surface

Theoretical studies of the operation of a device for pickling and moving bulk materials are discussed. A particular analysis of the Lagrange equation for the motion of a particle in a spiral-helical device is described. The images are presented with all forces and velocity vectors acting on a particle from the side of the spiral screw and the inner surface of the device body during its movement. The expression for the angle θ, which characterizes the geometric parameters of the spiral and cylindrical body, as well as the size of the material particles in the device, has been investigated and transformed.

P2S2-Bridged binuclear metal carbonyls from dimerization of coordinated thiophosphoryl groups: a theoretical study

2020 ◽  
Vol 44 (30) ◽  
pp. 12942-12948
Author(s):  
Zhong Zhang ◽  
Zuqing Chen ◽  
Zhipeng Yang ◽  
Jianping Wang ◽  
Liang Pu ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Theoretical Studies ◽  
Metal Carbonyls ◽  
Binuclear Metal

Theoretical studies indicate the complexes M(CO)n(PS) with bent 1-e/2-e donor PS groups to be unstable for giving the stable M(CO)n−1(PS) with linear 3-e donor PS groups. In addition, only Mn2(CO)8(P2S2) is energetically viable from the Mn(CO)4(PS).

Theoretical Study of Ethylene Addition to O=W(=CH2)(CH3)2

2007 ◽  
Vol 62 (3) ◽  
pp. 367-372 ◽  
Author(s):  
Robin Haunschild ◽  
Gernot Frenking
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Activation Barrier ◽  
Reaction Pathways ◽  
Theoretical Studies ◽  
Stable Isomer ◽  
Functional Theory ◽  
B3lyp Level ◽  
Rhenium Compound ◽  
Favorable Reaction

Quantum chemical calculations using density functional theory at the B3LYP level of theory were carried out to investigate the reaction pathways for the addition of ethylene to WO(CH3)2(CH2) (W1). The results are compared to those of previous theoretical studies of the ethylene addition to OsO3(CH2) (Os1) and ReO2(CH3)(CH2) (Re1). The theoretically predicted reactions pathways exhibit significant differences. The energetically most favourable reaction of the tungsten system W1 is the [2+2]W,C addition across theW=C double bond yielding the metallacyclobutane W3a which then rearranges to the slightly more stable isomer W3b. The [2+2]Re,C addition of the rhenium compound yielding the metallacyclobutane Re3a has the lowest activation barrier for the ethylene addition to the rhenium system, but the reaction is endothermic while the exothermic formation of the more stable isomer Re3b has a much higher activation barrier. The [3+2]C,O addition Os1+C2H4→Os2 is the thermodynamically most favorable reaction of the osmium compound.

Experimental and theoretical studies of the mica polymorphs

1956 ◽  
Vol 31 (234) ◽  
pp. 209-235 ◽  
Author(s):  
J. V. Smith ◽  
H. S. Yoder
Keyword(s):  
Growth Mechanism ◽  
Theoretical Study ◽  
Dominant Role ◽  
Spiral Growth ◽  
Theoretical Studies ◽  
X Ray ◽  
Layer Cell ◽  
Triclinic Structure ◽  
Experimental And Theoretical Studies ◽  
Made In

SummaryAn experimental and theoretical study has been made in order to determine the number and the structure of the possible polymorphs and to determine the structural relations between them. The simplest structures are 1M, 2M1, 2M2, 3T, 20, and 6H polymorphs, and more complicated types can be developed. Some of the previously described polymorphs were not contained in the theoretical list and were re-examined. The 6M structure was found to be a 2M2 polymorph, the 6-layer triclinic type was found to be a 2M1 polymorph, and the 3M structure was shown to be a 3T type. The 24-layer triclinic structure could be described on a simpler 8-layer cell. This type together with a new 12-layer monoclinic structure, as well as other structures of higher periodicity, presumably consists of complex stacking and results from spiral-growth mechanism. Two extreme types of layer-disordered crystals may be built and a disorder of individual ions may also occur. Single stacking faults result in twinned crystals. A new twin relation (180° rotation about the [100] axis) has been recognized. Twenty specimens from extreme geological environments have been examined in order to evaluate the control of environment on the stacking. The type of stacking could not be attributed solely to the influence of pressure and temperature. Composition appears to play a dominant role in the type of stacking, and semi-quantitative structural arguments appear to support this contention. The influence of growth mechanism is discussed. A scheme for the identification of the mica polymorphs by X-ray powder and single-crystal methods is given.

scholarly journals Performance Analysis of Maximal Risk Evaluation Formulas for Spectrum-Based Fault Localization

2020 ◽  
Vol 10 (1) ◽  
pp. 398 ◽  
Author(s):  
Tingting Wu ◽  
Yunwei Dong ◽  
Man Fai Lau ◽  
Sebastian Ng ◽  
Tsong Yueh Chen ◽  
...  
Keyword(s):  
Risk Evaluation ◽  
Theoretical Study ◽  
Ordered Set ◽  
Fault Localization ◽  
Research Area ◽  
Theoretical Studies ◽  
Effectiveness Analysis ◽  
Significant Research ◽  
Program Spectrum ◽  
Better Than

The effectiveness analysis of risk evaluation formulas has become a significant research area in spectrum-based fault localization (SBFL). The risk evaluation formula is designed and widely used to evaluate the likelihood of a program spectrum to be faulty. There are numerous empirical and theoretical studies to investigate and compare the performance between sixty risk evaluation formulas. According to previous research, these sixty risk evaluation formulas together form a partially ordered set. Among them, nine formulas are maximal. These nine formulas can further be grouped into five maximal risk evaluation formula groups so that formulas in the same group have the same performance. Moreover, previous research showed that we cannot theoretically compare formulas across these five maximal formula groups. However, experimental data “suggests” that a maximal formula in one group could outperform another one (from a different group) more frequently, though not always. This inspired us to further investigate the performance between any two maximal formulas in different maximal formula groups. Our approach involves two major steps. First, we propose a new condition to compare between two different maximal formulas. Based on this new condition, we present five different scenarios under which a formula performs better than another. This is different from the condition suggested by the previous theoretical study. We performed an empirical study to compare different maximal formulas using our condition. Our results showed that among two maximal risk evaluation formulas, it is feasible to identify one that can outperform the others more frequently.

Theoretical studies of azapentalenes. Part 4: Theoretical study of the properties of 3a,6a-diazapentalene

Tetrahedron ◽  
2009 ◽  
Vol 65 (29-30) ◽  
pp. 5760-5766 ◽  
Author(s):  
Ibon Alkorta ◽  
Fernando Blanco ◽  
José Elguero
Keyword(s):  
Theoretical Study ◽  
Theoretical Studies

INDO [intermediate neglect of differential overlap] theoretical studies. III. INDO theoretical study of the geometry of fluorinated methyl and allylic cations and radicals

1972 ◽  
Vol 94 (17) ◽  
pp. 5979-5985 ◽  
Author(s):  
Lowell D. Kispert ◽  
Charles U. Pittman ◽  
D. Lee Allison ◽  
T. B. Patterson ◽  
Charles W. Gilbert ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Theoretical Studies ◽  
Neglect Of Differential Overlap

scholarly journals Development and Theoretical Study of the Impact of the Working Body on the Soil

2021 ◽  
Vol 37 ◽  
pp. 00077
Author(s):  
Marat Kalimullin ◽  
Ramis Bagautdinov ◽  
Radik Khamitov ◽  
Rafkat Latypov ◽  
Marat Salimzyanov ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Lower Layer ◽  
Angle Of Attack ◽  
Soil Layer ◽  
Cutting Speed ◽  
Arbitrary Point ◽  
Theoretical Studies ◽  
Open Surface ◽  
Impact Speed ◽  
The Impact

The article discusses the features of the process of interaction of the blades of the teeth of the disk working body with the cultivated soil. If we take into account the fact that the parameters of the intensity of the impact exerted on the soil by the toothed working body will depend on the speed of movement, it will be possible to determine the values of the speed of an arbitrary point of the blade of the teeth. As a result of mathematical transformations and the application of the method of differentiation of the equation of their displacement, a formula was obtained for calculating the cutting speed for an arbitrary point of the blade of the teeth of a disk working body. Also, the acceleration of the points under consideration is determined and the dependences obtained as a result of theoretical studies are analyzed. The dependences demonstrate that the parameters of the impact speed and the trajectory of the blade movement directly depend on the shape of the cutting edge. They are also influenced by the angle of attack, the value of the inclination in relation to the vertical, as well as the speed of the planter movement. After analyzing the results obtained, it can be concluded that there is a noticeable decrease in the throwing of the upper soil layer to the side and the removal of the lower layer to the open surface of the field when exposed to a disk working body with teeth around the perimeter.

scholarly journals Renovation of Interest in the Magnetoelectric Effect in Nanoferroics

2018 ◽  
Vol 63 (11) ◽  
pp. 1006 ◽  
Author(s):  
M. D. Glinchuk ◽  
V. V. Khist
Keyword(s):  
Size Effects ◽  
Magnetoelectric Effect ◽  
Bulk Material ◽  
Bismuth Ferrite ◽  
Phenomenological Theory ◽  
Magnetoelectric Coupling ◽  
Theoretical Studies ◽  
Coupling Coefficients ◽  
Bulk Materials ◽  
Magnetoelectric Properties

Recent theoretical studies of the influence of the magnetoelectric effect on the physical properties of nanosized ferroics and multiferroics have been reviewed. Special attention is focused on the description of piezomagnetic, piezoelectric, and linear magnetoelectric effects near the ferroid surface in the framework of the Landau–Ginzburg–Devonshire phenomenological theory, where they are considered to be a result of the spontaneous surface-induced symmetry reduction. Therefore, nanosized particles and thin films can manifest pronounced piezomagnetic, piezoelectric, and magnetoelectric properties, which are absent for the corresponding bulk materials. In particular, the giant magnetoelectric effect induced in nanowires by the surface tension is possible. A considerable influence of size effects and external fields on the magnetoelectric coupling coefficients and the dielectric, magnetic, and magnetoelectric susceptibilities in nanoferroics is analyzed. Particular attention is paid to the influence of a misfit deformation on the magnetoelectric coupling in thin ferroic films and their phase diagrams, including the appearance of new phases absent in the bulk material. In the framework of the Landau–Ginzburg–Devonshire theory, the linear magnetoelectric and flexomagnetoelectric effects induced in nanoferroics by the flexomagnetic coupling are considered, and a significant influence of the flexomagnetic effect on the nanoferroic susceptibility is marked. The manifestations of size effects in the polarization and magnetoelectric properties of semiellipsoidal bismuth ferrite nanoparticles are discussed.

scholarly journals Theoretical study of the influence of the length of the spike on the cleaning effect of the fine litter cleaner

2021 ◽  
Vol 304 ◽  
pp. 03038
Author(s):  
Ruzimurad Rosulov ◽  
Anvar Djuraev ◽  
Husan Diyorov ◽  
Umid Berdimurodov
Keyword(s):  
Theoretical Study ◽  
Theoretical Studies ◽  
Schematic Diagram ◽  
The Law

In the article, a schematic diagram and principle of operation of the recommended raw cotton cleaner from fine litter are provide. The article presents the results of theoretical studies of the effect of the length of the pegs on the cleaning effect of the raw cotton cleaner. Based on the study of the law of movement of raw cotton on the surface of the splitter, graphical dependences of the change in the length of the splitter on the change in the mass of cotton are constructed. Substantiation of the length of the drum heads of the corresponding areas for cleaning cotton from fine litter.

scholarly journals Experimental and Theoretical Studies of the Gas-Phase Reactions of O(1D) with H2O and D2O at Low Temperature

2021 ◽  
Author(s):  
Kevin M. Hickson ◽  
Somnath Bhowmick ◽  
Yury V. Suleimanov ◽  
João Brandão ◽  
Daniela V. Coelho
Keyword(s):  
Low Temperature ◽  
Gas Phase ◽  
Room Temperature ◽  
Theoretical Study ◽  
Theoretical Studies ◽  
Gas Phase Reactions ◽  
Experimental And Theoretical Studies

Here we report the results of an experimental and theoretical study of the gas-phase reactions between O(1D) and H2O and O(1D) and D2O at room temperature and below. On the...

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