scholarly journals The Lobe-Type Agitator Parameters of the Seed-Metering Unit in the Seed-Fertilizer Drill Justification

2018 ◽  
Vol 12 (5) ◽  
pp. 20-24
Author(s):  
D. Z. Yeskhozhin ◽  
S. O. Nukeshev ◽  
G. I. Lichman ◽  
Ye. S. Akhmetov ◽  
K. D. Yeskhozhin
Keyword(s):  
Experimental Studies ◽  
Soil Productivity ◽  
Theoretical Studies ◽  
Total Resistance ◽  
Applied Mechanics ◽  
Main Indicator ◽  
Farm Produce ◽  
The Republic ◽  
Seed Medium ◽  
Livestock Products

Livestock products are the most important component of the actual total volume of farm produce. A reliable fodder base is required to increase their quantity and quality. The most part of the natural forage lands of the Republic of Kazakhstan is located in areas with insufficient water availability and low soil productivity. When they are used intensively, they are thinned and degraded. Their restoration and improving is possible if effective technologies and technical means are effected. However, the existing methods for improving and restoring forage lands and the technical means for their implementation are not adapted to the natural­climatic and agrobiological features of the zone of Central and Northern Kazakhstan, which feature insufficient moisture supply and low productivity.The main indicator of the effectiveness of the use of fodder crop seeds is their uniform distribution in the soil. However, most of them, due to their poor flowability, form dome structures of different sizes in front of seeding openings, which hinder the seeding process. To increase the flowability of such seeds, they are mixed with sand, sawdust, fertilizer and other materials. However, during the operation of seeders, the mixture is stratified according to its specific gravity. (The research purpose) is to develop a lobe­type agitator, which prevents the formation of a dome over seed holes. (Materials and methods) Theoretical studies have been carried out using the methods of classical and applied mechanics, as well as special sections of higher mathematics. (Results and discussion) The authors have experimentally confirmed the main parameters of the agitator and its resistance to movement in a seed medium. Experimental studies have been carried out on the basis of GOST 31345­2007. The studies have confirmed that a four­lobe agitator with an external radius of 0.06 m and an inclination angle to the plane of rotation 20°, mounted on the fertilizer drill SZS­2.0, has shown a total resistance of 3,042 kg with a design value of 2.925 kg. (Conclusions) The obtained results can be offered to the designers and developers of machines of the considered type when calculating and designing their working elements.

Strong coupling: resonant effects

2017 ◽  
Author(s):  
Alexey V. Kavokin ◽  
Jeremy J. Baumberg ◽  
Guillaume Malpuech ◽  
Fabrice P. Laussy
Keyword(s):  
Strong Coupling ◽  
Experimental Studies ◽  
Strong Coupling Regime ◽  
Theoretical Studies ◽  
Stimulated Scattering ◽  
Quantum Theories ◽  
Pump Probe ◽  
Exciton Polaritons ◽  
Linear Optical Properties ◽  
Experimental And Theoretical Studies

This chapter presents experimental studies performed on planar semiconductor microcavities in the strong-coupling regime. The first section reviews linear experiments performed in the 1990s that evidence the linear optical properties of cavity exciton-polaritons. The chapter is then focused on experimental and theoretical studies of resonantly excited microcavity emission. We mainly describe experimental configuations in which stimulated scattering was observed due to formation of a dynamical condensate of polaritons. Pump-probe and cw experiments are described in addition. Dressing of the polariton dispersion and bistability of the polariton system due to inter-condensate interactions are discussed. The semiclassical and the quantum theories of these effects are presented and their results analysed. The potential for realization of devices is also discussed.

Calculation of Technical Characteristics of the Technical Fleet Vessels Involved in Ensuring Safety of the Offshore Facilities of Oil and Gas Complex

2021 ◽  
pp. 7-13
Author(s):  
S.V. Matsenko ◽  
◽  
V.M. Minko ◽  
A.A. Koshelev ◽  
V.Yu. Piven ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Oil Pollution ◽  
Raw Materials ◽  
Experimental Studies ◽  
Industrial Safety ◽  
Theoretical Studies ◽  
Physical Processes ◽  
Oil Spill Response ◽  
Sea Area

Violation of industrial safety rules during the operation of offshore facilities for the production, storage and transportation of the hydrocarbon raw materials leads in the most cases to pollution of the marine environment with oil and its components. The works on localization and elimination of such pollution are carried out with the help of vessels of the technical support fleet and booms. When developing oil spill response plans at such facilities, a calculated determination of the technical characteristics of vessels and booms is required that are sufficient to carry out the planned activities. The basic design principles for determining the towing capacity of the technical fleet vessels involved in the localization and elimination of oil and oil product spills by trawling methods are given in the article. The calculation is based on theoretical studies performed by the authors of the physical processes occurring during the movement of objects of a mobile trawling order in the sea area. The results obtained during the course of theoretical studies were confirmed by the experimental studies carried out by the authors personally using the real pieces of equipment in the actual development of tasks for training spill containment by trawling. As a result, the empirical dependencies were obtained and experimentally confirmed, which can be used to calculate technical characteristics of the ships as part of the mobile orders and anchor systems as part of stationary orders intended for the localization and elimination of oil pollution. These results can be used, among other things, for the calculated substantiation of the technical characteristics of the technical fleet vessels designed to ensure safety of the offshore facilities for production, storage, and transportation of the hydrocarbon raw materials.

scholarly journals MHD-waves in the geomagnetic tail: A review

10.12737/7168 ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 4-22 ◽  
Author(s):  
Анатолий Леонович ◽  
Anatoliy Leonovich ◽  
Виталий Мазур ◽  
Vitaliy Mazur ◽  
Даниил Козлов ◽  
...  
Keyword(s):  
Numerical Models ◽  
Experimental Studies ◽  
Low Frequency ◽  
Detailed Comparison ◽  
Mhd Waves ◽  
Theoretical Studies ◽  
Geomagnetic Tail ◽  
Magnetopause Oscillations ◽  
Experimental And Theoretical Studies ◽  
Theoretical Results

This article presents the review of experimental and theoretical studies on ultra-low-frequency MHD oscillations of the geomagnetic tail. We consider the Kelvin–Helmholtz instability at the magnetopause, oscillations with a discrete spectrum in the “magic frequencies” range, the ballooning instability of coupled Alfvén and slow magnetosonic waves, and “flapping” oscillations of the current sheet of the geomagnetic tail. Over the last decade, observations from THEMIS, CLUSTER and Double Star satellites have been of great importance for experimental studies. The use of several spacecraft allows us to study the structure of MHD oscillations with high spatial resolution. Due to this, we can make a detailed comparison between theoretical results and those obtained from multi-spacecraft studies. To make such comparisons in theoretical studies, in turn, we have to use the numerical models closest to the real magnetosphere.

scholarly journals Sunlight-driven photocatalytic hydrogen production from water using metal-doped strontium titanate perovskite

2020 ◽  
Author(s):  
Pushkal Sharma ◽  
Cheng-Ting Lee ◽  
Jeffrey Chi-Sheng Wu
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Strontium Titanate ◽  
Experimental Studies ◽  
Light Response ◽  
Theoretical Studies ◽  
Photocatalytic Water Splitting ◽  
Visible Light Response ◽  
Sacrificial Agent ◽  
Metal Doped

<div>The effects of various metal dopants on the photocatalytic water splitting activity of SrTiO<sub>3</sub> -based photocatalysts were investigated using experimental studies. The SrTiO<sub>3</sub>:Rh (1%) has been found to give the best efficiency in water splitting out of the various metal-doped samples studied. However, the same host doped with other metal dopants such as Fe, V, Ga, and Sb leads to negligible hydrogen evolution even when at least Fe has a better visible light response. Our results accompanied by previously conducted theoretical studies by our group explain the high photocatalytic water splitting activity of Rh doped SrTiO<sub>3 </sub>. Furthermore, the effects of the amount of catalyst, the proportion of sacrificial agent and pH were studied for the SrTiO<sub>3</sub>:Rh (1 mol%) along with studying its activity with seawater.</div>

scholarly journals THE QUANTIZED HALL INSULATOR: A "QUANTUM" SIGNATURE OF A "CLASSICAL" TRANSPORT REGIME?

2004 ◽  
Vol 18 (18) ◽  
pp. 923-943 ◽  
Author(s):  
EFRAT SHIMSHONI
Keyword(s):  
Quantum Interference ◽  
Random Network ◽  
Experimental Studies ◽  
Localization Length ◽  
Theoretical Studies ◽  
Hall Resistivity ◽  
Transport Regime ◽  
Open Questions ◽  
Weakly Coupled ◽  
Classical Transport

Experimental studies of the transitions from a primary quantum Hall (QH) liquid at filling factor ν=1/k (with k an odd integer) to the insulator have indicated a "quantized Hall insulator" (QHI) behavior: while the longitudinal resistivity diverges with decreasing temperature and current bias, the Hall resistivity remains quantized at the value kh/e2. We review the experimental results and the theoretical studies addressing this phenomenon. In particular, we discuss a theoretical approach which employs a model of the insulator as a random network of weakly coupled puddles of QH liquid at fixed ν. This model is proved to exhibit a robust quantization of the Hall resistivity, provided the electron transport on the network is incoherent. Subsequent theoretical studies have focused on the controversy whether the assumption of incoherence is necessary. The emergent conclusion is that in the quantum coherent transport regime, quantum interference destroys the QHI as a consequence of localization. Once the localization length becomes much shorter than the dephasing length, the Hall resistivity diverges. We conclude by mentioning some recent experimental observations and open questions.

scholarly journals Sparse coding in striate and extrastriate visual cortex

2011 ◽  
Vol 105 (6) ◽  
pp. 2907-2919 ◽  
Author(s):  
Ben D. B. Willmore ◽  
James A. Mazer ◽  
Jack L. Gallant
Keyword(s):  
Visual Cortex ◽  
Action Potentials ◽  
Experimental Studies ◽  
Natural Images ◽  
Theoretical Studies ◽  
Exponential Distributions ◽  
Neural Codes ◽  
Firing Rates ◽  
Visual Hierarchy ◽  
Primate Visual Cortex

Theoretical studies of mammalian cortex argue that efficient neural codes should be sparse. However, theoretical and experimental studies have used different definitions of the term “sparse” leading to three assumptions about the nature of sparse codes. First, codes that have high lifetime sparseness require few action potentials. Second, lifetime-sparse codes are also population-sparse. Third, neural codes are optimized to maximize lifetime sparseness. Here, we examine these assumptions in detail and test their validity in primate visual cortex. We show that lifetime and population sparseness are not necessarily correlated and that a code may have high lifetime sparseness regardless of how many action potentials it uses. We measure lifetime sparseness during presentation of natural images in three areas of macaque visual cortex, V1, V2, and V4. We find that lifetime sparseness does not increase across the visual hierarchy. This suggests that the neural code is not simply optimized to maximize lifetime sparseness. We also find that firing rates during a challenging visual task are higher than theoretical values based on metabolic limits and that responses in V1, V2, and V4 are well-described by exponential distributions. These findings are consistent with the hypothesis that neurons are optimized to maximize information transmission subject to metabolic constraints on mean firing rate.

scholarly journals Numerical simulation of the stress-strain state of complex-reinforced elements

2019 ◽  
Vol 13 (2) ◽  
pp. 110-115
Author(s):  
Olena Krantovska ◽  
Mykola Petrov ◽  
Liubov Ksonshkevych ◽  
Matija Orešković ◽  
Sergii Synii ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Strain State ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Theoretical Studies ◽  
Stress Strain ◽  
Narrow Strip ◽  
Stress Strain State ◽  
Graphical Environment ◽  
Experimental And Theoretical Studies

The article describes a developed technique of a numerical simulation of the stress-strain state of complex-reinforced elements, which allows you to create models of double-span continuous. The performed experimental and theoretical studies allowed us to carry out the testing of the developed design model and to justify the reliability of the proposed numerical simulation methodology. The results of the experimental studies were compared with those of the theoretical studies. The theoretical calculus algorithm was developed by using the finite element method. Theoretical calculations were performed by using the mathematical-graphical environment software system LIRA-SOFT and the mathematical and computer program MATLAB. On the basis of the experimental research, the iso-fields of displacements and stresses in the materials of an eccentrically compressed beam with a small bend of the slab were constructed, which collapse behind the inclined narrow strip of concrete and displacements and stresses in the materials of the eccentrically stretched beam, which is destroyed due to the yield of the upper mounting armature.

scholarly journals Experimental and theoretical studies on the photodegradation of 2-ethylhexyl 4-methoxycinnamate in the presence of reactive oxygen and chlorine species

2014 ◽  
Vol 12 (5) ◽  
pp. 612-623 ◽  
Author(s):  
Alicja Gackowska ◽  
Maciej Przybyłek ◽  
Waldemar Studziński ◽  
Jerzy Gaca
Keyword(s):  
Experimental Studies ◽  
Fukui Function ◽  
Mass Spectrometric ◽  
Theoretical Studies ◽  
Reaction Products ◽  
Reactivity Indices ◽  
Mass Spectrometric Detector ◽  
Methoxycinnamic Acid ◽  
Experimental And Theoretical Studies ◽  
Dft And Mp2 Calculations

Abstract2-Ethylhexyl 4-methoxycinnamate (EHMC) is one of the most commonly used sunscreen ingredient. In this study we investigated photodegradation of EHMC in the presence of such common oxidizing and chlorinating systems as H2O2, H2O2/HCl, H2O2/UV, and H2O2/HCl/UV. Reaction products were detected by gas chromatography with a mass spectrometric detector (GC-MS). As a result of experimental studies chloro-substituted 4-methoxycinnamic acid (4-MCA), 4-methoxybenzaldehyde (4-MBA) and 4-methoxyphenol (4-MP) were identified. Experimental studies were enriched with DFT and MP2 calculations. We found that reactions of 4-MCA, 4-MBA and 4-MP with Cl2 and HOCl were in all cases thermodynamically favorable. However, reactivity indices provide a better explanation of the formation of particular chloroorganic compounds. Generally, those isomeric forms of mono- and dichlorinated compounds which exhibits the highest hardness were identified. Nucleophilicity of the chloroorganic compounds precursors were examined by means of the Fukui function.

scholarly journals Data processing method for experimental studies of deformation in a rock sample under uniaxial compression

2019 ◽  
Vol 129 ◽  
pp. 01018
Author(s):  
Andrei Golosov ◽  
Olga Lubimova ◽  
Mikhail Zhevora ◽  
Vladislava Markevich ◽  
Vladimir Siskov
Keyword(s):  
Rock Sample ◽  
Experimental Studies ◽  
Main Element ◽  
Theoretical Studies ◽  
Dynamic Changes ◽  
New Approach ◽  
Rock Samples ◽  
Data Processing Method ◽  
Patterns Of Behavior ◽  
Experimental And Theoretical Studies

As a result of experimental and theoretical studies, the patterns of behavior of rocks in a condition close to destructive are the focal nature of the preparation of macrocracking, which allowed us to include the mesocrack structure of the material, which is the main element in the preparation of macrocracking. Differences in this new approach to mathematical modeling will let adequately describe dissipative mesocrack structures of various hierarchical levels of geodesy, predict dynamic changes, structures and mechanical properties of both rock samples and massif, which also lead to resource-intensive experimental studies. In this paper, with usage of the methods of cluster, factor, and statistical analysis, we set the task of processing the data of experimental studies of the laws of deformation and preparing macro-fracture of rock samples by various methods, including acoustic and deformation observations.

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