VIBRODIAGNOSTICS OF HINGE ELEMENTS CAR SUSPENSION

2020 ◽  
Vol 71 (4) ◽  
pp. 3-10
Author(s):  
A.Yu. RODICHEV ◽  
◽  
M.D. TEBEKIN ◽  
A.V. GORIN ◽  
S.V. KOLPAKOVA ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Experimental Study ◽  
Technical Condition ◽  
Theoretical Studies ◽  
Ball Joint ◽  
Theoretical Methods ◽  
Design Scheme ◽  
Car Suspension ◽  
Analysis Of Failures ◽  
Experimental And Theoretical Studies

The article contains an analysis of failures of articulated elements of automotive equipment. The paper presents a mathematical model for changing the technical condition of the ball joint of automotive vehicles. A design scheme is proposed, assumptions and limitations for a mathematical model are determined. During the work, experimental and theoretical studies were carried out. To assess the reliability of the results obtained by theoretical methods, an experimental study was car-ried out on the developed installation using vibration methods.

Features of wave propagation in the sand of different saturation

2011 ◽  
Vol 8 (1) ◽  
pp. 25-38
Author(s):  
A.T. Akhmetov ◽  
S.V. Lukin ◽  
D.M. Balapanov ◽  
S.F. Urmancheev ◽  
N.M. Gumerov ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Porous Medium ◽  
Porous Media ◽  
Wave Propagation ◽  
Water Saturation ◽  
Weak Shock ◽  
Capillary Forces ◽  
Theoretical Studies ◽  
Longitudinal Waves ◽  
Experimental And Theoretical Studies

There are the results of experimental and theoretical studies on the propagation of weak shock waves in the wet sand at different water saturation. There are mathematical model and numerical analysis of propagation of pressure pulses in porous media, taking into account capillary forces. Non-monotonic dependence of the amplitude of the wave resulting in a wet porous medium vs. the degree of water saturation is installed. The evolution of the fast, slow and filtration waves depends on the saturation of the system with water is analyzed. The influence of capillary forces on the propagation of longitudinal waves is evaluated.

scholarly journals Combined experimental and theoretical studies of regio- and stereoselectivity in reactions of β-isoxazolyl- and β-imidazolyl enamines with nitrile oxides

2016 ◽  
Vol 12 ◽  
pp. 2390-2401 ◽  
Author(s):  
Ilya V Efimov ◽  
Marsel Z Shafikov ◽  
Nikolai A Beliaev ◽  
Natalia N Volkova ◽  
Tetyana V Beryozkina ◽  
...  
Keyword(s):  
Room Temperature ◽  
Cycloaddition Reaction ◽  
Theoretical Studies ◽  
Dispersion Correction ◽  
Dioxane Solution ◽  
Theoretical Methods ◽  
Effective Catalyst ◽  
Nitrile Oxides ◽  
Catalyst Free ◽  
Experimental And Theoretical Studies

Reactions of β-azolyl enamines and nitrile oxides were studied by both experimental and theoretical methods. (E)-β-(4-Nitroimidazol-5-yl), (5-nitroimidazol-4-yl) and isoxazol-5-yl enamines smoothly react regioselectively at room temperature in dioxane solution with aryl, pyridyl, and cyclohexylhydroxamoyl chlorides without a catalyst or a base to form 4-azolylisoxazoles as the only products in good yields. The intermediate 4,5-dihydroisoxazolines were isolated as trans isomers during the reaction of (E)-β-imidazol-4-yl enamines with aryl and cyclohexylhydroxamoyl chlorides. Stepwise and concerted pathways for the reaction of β-azolyl enamines with hydroxamoyl chlorides were considered and studied at the B3LYP/Def2-TZVP level of theory combined with D3BJ dispersion correction. The reactions of benzonitrile oxide with both E- and Z-imidazolyl enamines have been shown to proceed stereoselectively to form trans- and cis-isoxazolines, respectively. The preference of E-isomers over Z-isomers, driven by the higher stability of the former, apparently controls the stereoselectivity of the investigated cycloaddition reaction with benzonitrilе oxide. Based on the reactivity of azolyl enamines towards hydroxamoyl chlorides, a novel, effective catalyst-free method was elaborated to prepare 4-azolyl-5-substituted isoxazoles that are otherwise difficult to obtain.

A Discussion on the measurement and interpretation of changes of strain in the Earth - Earth tides and their place in geophysics (summary)

1973 ◽  
Vol 274 (1239) ◽  
pp. 199-202 ◽  
Keyword(s):  
Experimental Study ◽  
Solid Earth ◽  
Earth Tides ◽  
Theoretical Studies ◽  
The Earth ◽  
The Future ◽  
Gravity Variations ◽  
Analytical Procedures ◽  
Experimental And Theoretical Studies

The experimental study of tidal phenomena in the solid Earth has been pursued for a century and, in particular, the last 15 years since the I.G.Y. has seen a spectacular growth in activity. The geophysical significance of the work has remained limited however, and it is necessary to study possible reasons for these shortcomings. Work in the U.K. on tilt and gravity variations has helped to identify some of the relevant problems associated with the philosophy of instrumentation and its deployment, calibration, experimental repeatability, and analytical procedures. Here the importance of the oceanic influence is clear, whereas elsewhere it has not always been accorded sufficient attention. The future of the discipline may lie in a decline in interest in body effects and a greater concentration upon the mantle, the crust and their inhomogeneities in which experimental and theoretical studies proceed in parallel.

scholarly journals Связь мощности дозы гамма-излучения с интенсивностью ливневых осадков

2021 ◽  
pp. 189-199
Author(s):  
A.S. Zelinskiy ◽  
G.A. Yakovlev ◽  
D.E. Fil’trov
Keyword(s):  
Mathematical Model ◽  
Surface Layer ◽  
Dose Rate ◽  
Atmospheric Precipitation ◽  
Quantitative Relationship ◽  
Theoretical Studies ◽  
Radiation Dose Rate ◽  
Γ Radiation ◽  
Rate Of Increase ◽  
Experimental And Theoretical Studies

Experimental and theoretical studies of the influence of the intensity, amount and duration of liquid atmospheric precipitation on the formation of γ-background in the surface layer of the atmosphere are presented. It was observed that precipitation causes an increase in the γ-radiation dose rate in the form of bursts. In this case, the total amount of precipitation in an event determines the magnitude of the burst of the dose rate, and the intensity of precipitation determines the rate of increase in the dose rate of γ-radiation. A mathematical model, which establishes a quantitative relationship between the dose rate of γ-radiation and the intensity (amount) of liquid atmospheric precipitation has been developed and verified (R2 = 0.93). Представлены экспериментальные и теоретические исследования влияния интенсивности, количества и продолжительности жидких атмосферных осадков на формирование γ-фона в приземном слое атмосферы. Было замечено, что осадки вызывают увеличение мощности дозы γ-излучения в виде всплесков. В этом случае общее количество осадков в событии определяет величину всплеска мощности дозы, а интенсивность осадков определяет скорость увеличения мощности дозы γ-излучения. Разработана и проверена математическая модель, устанавливающая количественную связь между мощностью дозы γ-излучения и интенсивностью (количеством) жидких атмосферных осадков (R2 = 0,93).

scholarly journals Wear and reliability of cylindrical vehicle joints

2020 ◽  
Vol 97 (3) ◽  
pp. 64-69
Author(s):  
A. Dykha ◽  
◽  
J. Padgurskas ◽  
Yu. Kukurudzyak ◽  
O. Babak ◽  
...  
Keyword(s):  
Experimental Study ◽  
Service Life ◽  
Computational Method ◽  
Friction Unit ◽  
System Of Equations ◽  
Ball Joint ◽  
Spherical Contact ◽  
Reliability Indicators ◽  
Car Suspension

A method for calculating the wear of car suspension liners is presented. To determine the wear by a computational method, a system of equations for the spherical contact of mates of the friction unit of a car was obtained. An example of calculating wear for a given service life of a ball joint is given. The issue of determining the reliability indicators of a cylindrical hinge by the wear criterion is considered. An experimental study of the effectiveness of various greases for car hinge joints has been carried out.

The Stabilizing Effect of Pre-Equilibria: A Trifluoromethyl Complex as CF2 Reservoir in Catalytic Olefin Difluorocarbenation

2020 ◽  
Author(s):  
Thomas Louis-Goff ◽  
Huu Vinh Trinh ◽  
Eileen Chen ◽  
Arnold L. Rheingold ◽  
Christian Ehm ◽  
...  
Keyword(s):  
High Selectivity ◽  
Side Reactions ◽  
Theoretical Studies ◽  
Attractive Feature ◽  
Catalyst Recovery ◽  
Wide Range ◽  
Stabilizing Effect ◽  
Experimental And Theoretical Studies

A new, efficient, catalytic difluorocarbenation of olefins to give 1,1-difluorocyclopropanes is presented. The catalyst, an organobismuth complex, uses TMSCF<sub>3</sub> as a stoichiometric difluorocarbene source. We demonstrate both the viability and robustness of this reaction over a wide range of alkenes and alkynes, including electron-poor alkenes, to generate the corresponding 1,1-difluorocyclopropanes and 1,1-difluorocyclopropenes. Ease of catalyst recovery from the reaction mixture is another attractive feature of this method. In depth experimental and theoretical studies showed that the key difluorocarbene-generating step proceeds through a bismuth non-redox synchronous mechanism generating a highly reactive free CF<sub>2</sub> in an endergonic pre-equilibrium. It is the reversibility when generating the difluorocarbene that accounts for the high selectivity, while minimizing CF<sub>2</sub>-recombination side-reactions.

Sign in / Sign up

Export Citation Format

Share Document