approximate calculation
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2021 ◽  
Vol 15 (1) ◽  
pp. 13
Author(s):  
Qing Li

An approximate calculation of the spatial characteristics on finite range is required, so one quantitative continuum represents the accumulation of infinite great quantities is artificially divided it into smaller and camparable parts in which calculus operation can be applied .This operation is defined as Theorem 1 in which infinity is not involved, there is a camparable finity is constantly (forever) approaching and not reaching infinity, and only staying within a finite range. Theorem 1 can exist in this paper as a new mathematical basis for physics. Because the essence of all physical quantities is size comparison, and the size comparison relation of matter can only be space/time, so relation formula space/time is the only expression of the concept of matter, all physical quantities are applicable to this expression, each different physical quantity is a multi-dimensional representation of this expression. A new mass energy formula is aslo derived from this paper.


2021 ◽  
Vol 63 (11) ◽  
pp. 29-34
Author(s):  
Thanh Dam Nguyen ◽  
◽  
Thi Phuc Nguyen ◽  
Minh Tuan Vu ◽  
◽  
...  

pH buffers of weak organic acids and bases are essential in capillary electrophoresis (CE) analyses, primarily when contactless conductivity detectors (C4D) are used. However, the preparation of a buffer with a known concentration of one component for use as a background electrolyte (BGE) in CE-C4D usually requires a pH adjustment to the desired value and an approximate calculation to estimate the concentration of the second component. This study developed software that allowed determining the concentration of one component when knowing the concentration of another component and the pH of the solution, taking into account the influence of ionic strength. The software was built in C# language with Windows Form interface on Microsoft Visual Studio. With the concentrations calculated from the developed software, the differences (|ΔpH|) between pH values of the obtained BGEs in practice and the desired values were smaller than 0.07, corresponding to the errors of less than 2%.


Author(s):  
А.А. Сокуров

В работе рассмотрены математические модели осесимметричных капиллярных менисков — лежащая и висящая капли, развернутый мениск, учитывающие размерную зависимость поверхностного натяжения. Доказаны теоремы существования и единственности решений задач, описывающих равновесные поверхности менисков. Разработаны и протестированы эффективные численные методы, предназначенные для приближенного расчета профилей менисков. На языке «Wolfram Language» написана компьютерная программа, с помощью которой проведены масштабные вычислительные эксперименты по выявлению степени и характера влияния параметров моделей на равновесную форму каждого из рассматриваемых менисков In the current paper we consider the mathematical models of axisymmetric capillary menisci — sessile and pendant drops, rolled out meniscus, taking into account the size dependence of surface tension. Existence and uniqueness theorems for solutions of problems describing equilibrium meniscus surfaces are proved. Effective numerical methods have been developed and tested for the approximate calculation of meniscus profiles. A computer program is written in the Wolfram Language, with the help of which large-scale computational experiments were carried out to reveal the degree and nature of the influence of the model parameters on the equilibrium shape of each type of menisci.


2021 ◽  
Vol 71 (2) ◽  
pp. 151-166
Author(s):  
Maistruk Pavlo ◽  
Lanets Oleksii ◽  
Stupnytskyy Vadym

Abstract The first natural frequency of oscillations of the vibrations of a discrete-continuous interresonant vibrating table plate was found using the functions of the Krylov-Duncan. The continuous member, presented in a plate hinged at four points, is used as a reactive mass with distributed parameters to create an inter-resonance vibrating table with an electromagnetic drive. For this purpose, the plate was considered as a rod on hinged supports. The justification of this approach is confirmed by simulation in the Ansys software. The results were confirmed using the approximate Rayleigh-Ritz method. The geometric shape of the plate is reduced to a section of a hyperboloidal surface. The results of simulation of the first natural frequency were verified experimentally.


2021 ◽  
Vol 65 (3) ◽  
pp. 46-59

This paper studies the problem of construction of optimal quadrature formulas for approximate calculation of integrals with trigonometric weight in the L(2m)(0, 1) space for any ω ൐= 0, ω ∈ R. Here explicit formulas for the optimal coefficients are obtained. We study the order of convergence of the optimal formulas for the case m = 1, 2. The obtained optimal quadrature formulas are exact for Pm−1(x), where Pm−1(x) is a polynomial of degree (m − 1).


2021 ◽  
Vol 12 (2) ◽  
pp. 863-873
Author(s):  
Qing Yin ◽  
Jianli Zhao ◽  
Yong Liu ◽  
Yisheng Zhang

Abstract. Vibration damper is widely used in overhead transmission lines to alleviate aeolian vibration. Its natural frequencies are important parameters for a vibration damper. In this paper, the approximate calculation formulas of natural frequencies of the one-side subsystem of a Stockbridge type vibration damper were derived and the design sensitivity analysis of the natural frequencies was studied using partial differential equations with respect to each concerned parameter including the length of the steel strand, the mass of the counterweight, the eccentric distance, and the radius of gyration of the counterweight. Through a case study that considered a variation of up to ±30 % in the values of the design parameters, the exact calculation and approximate calculation results of the natural frequencies were analysed, and the sensitivity of the vibration damper's natural frequencies to the design parameters was studied. The results show that, within the range of the parameters used in this study, the approximately calculated first-order frequency is lower than the exact values, whereas the approximately calculated second-order frequency is larger than the exact values. The sensitivity analysis indicates that the first-order frequency is highly sensitive to the steel strand's length, whereas it is moderately sensitive to the counterweight's mass and slightly sensitive to the eccentric distance and the gyration radius of the counterweight; the second-order frequency is highly sensitive to the steel strand's length and the gyration radius of the counterweight, moderately sensitive to the counterweight's mass, and slightly sensitive to the eccentric distance. It will provide theoretical guidance and approximate analysis method in engineering for the design of the vibration damper.


Author(s):  
Qing Li

An approximate calculation of the spatial characteristics on finite range is required, so one quantitative continuum represents the accumulation of infinite great quantities is artificially divided it into smaller and camparable parts in which calculus operation can be applied .This operation is defined as Theorem 1 in which infinity is not involved, there is a camparable finity is constantly (forever) approaching and not reaching infinity, and only staying within a finite range. Theorem 1 can exist in this paper as a new mathematical basis for physics. Because the essence of all physical quantities is size comparison, and the size comparison relation of matter can only be space/time, so relation formula space/time is the only expression of the concept of matter, all physical quantities are applicable to this expression, each different physical quantity is a multi-dimensional representation of this expression. A new mass energy formula is aslo derived from this paper.


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