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1 – 10 of 205
Article
Publication date: 21 September 2012

Bao‐jun Lin, Ge Yu, Shen‐hua Yang, Shu‐qing Kou and Jiu‐he Wang

Aiming at the positioning accuracy control problem in the running of the assembly machine for assembled camshaft, a kind of position controller based on the feedforward‐feedback…

Abstract

Purpose

Aiming at the positioning accuracy control problem in the running of the assembly machine for assembled camshaft, a kind of position controller based on the feedforward‐feedback control of speed and acceleration is designed.

Design/methodology/approach

It combines feedforward‐feedback control with the quartic displacement curve acceleration/deceleration algorithm.

Findings

The axial dimension and the phase angle of the cam obtained after being assembled is checked. The result shows that for each type of camshaft, the error of the axial dimension of the cam is less than ±0.2mm and the error of the phase angle of the cam is less than ±30′. In addition, production efficiency is greatly improved (the assembling time is 90‐120S/piece).

Originality/value

The paper combines feedforward‐feedback control with the quartic displacement curve acceleration/deceleration algorithm for the first time.

Article
Publication date: 15 February 2008

Ali Şahin, İdris Dağ and Bülent Saka

This paper seeks to develop an efficient B‐spline Galerkin scheme for solving the Fisher's equation, which is a nonlinear reaction diffusion equation describing the relation…

Abstract

Purpose

This paper seeks to develop an efficient B‐spline Galerkin scheme for solving the Fisher's equation, which is a nonlinear reaction diffusion equation describing the relation between the diffusion and nonlinear multiplication of a species.

Design/methodology/approach

The solution domain is partitioned into uniform mesh and, using the quartic B‐spline functions, the Galerkin method is applied to the Fisher's equation.

Findings

The method yields stable accurate solutions. Obtained results are acceptable and in unison with some earlier studies.

Originality/value

Using the uniform mesh, quartic B‐spline Galerkin method is employed for finding the numerical solutions of Fisher's equation.

Details

Kybernetes, vol. 37 no. 2
Type: Research Article
ISSN: 0368-492X

Keywords

Article
Publication date: 29 December 2017

O.K. Koriko, I.L. Animasaun, M. Gnaneswara Reddy and N. Sandeep

The purpose of this paper is to scrutinize the effects of nonlinear thermal radiation and thermal stratification effects on the flow of three-dimensional Eyring-Powell 36 nm…

107

Abstract

Purpose

The purpose of this paper is to scrutinize the effects of nonlinear thermal radiation and thermal stratification effects on the flow of three-dimensional Eyring-Powell 36 nm alumina-water nanofluid within the thin boundary layer in the presence of quartic autocatalytic kind of chemical reaction effects, and to unravel the effects of a magnetic field parameter, random motion of the tiny nanoparticles and volume fraction on the flow.

Design/methodology/approach

The chemical reaction between homogeneous (Eyring-Powell 36 nm alumina-water) bulk fluid and heterogeneous (three molecules of the catalyst at the surface) in the flow of magnetohydrodynamic three-dimensional flow is modeled as a quartic autocatalytic kind of chemical reaction. The electromagnetic radiation which occurs within the boundary layer is treated as the nonlinear form due to the fact that Taylor series expansion may not give full details of such effects within the boundary layer. With the aid of appropriate similarity variables, the nonlinear coupled system of partial differential equation which models the flow was reduced to ordinary differential equation boundary value problem.

Findings

A favorable agreement of the present results is obtained by comparing it for a limiting case with the published results; hence, reliable results are presented. The concentration of homogeneous bulk fluid (Eyring-Powell nanofluid) increases and decreases with ϕ and Pr, respectively. The increase in the value of magnetic field parameter causes vertical and horizontal velocities of the flow within the boundary layer to decrease significantly. The decrease in the vertical and horizontal velocities of Eyring-Powell nanofluid flow within the boundary layer is guaranteed due to an increase in the value of M. Concentration of homogeneous fluid increases, while the concentration of the heterogeneous catalyst at the wall decreases with M.

Originality/value

Considering the industrial applications of thermal stratification in solar engineering and polymer processing where the behavior of the flow possesses attributes of Eyring-Powell 36 nm alumina-water, this paper presents the solution of the flow problem considering 36 nm alumina nanoparticles, thermophoresis, stratification of thermal energy, Brownian motion and nonlinear thermal radiation. In addition, the aim and objectives of this paper fill such vacuum in the industry.

Details

Multidiscipline Modeling in Materials and Structures, vol. 14 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 26 October 2020

Özlem Ersoy Hepson

The purpose of this study is to construct quartic trigonometric tension (QTT) B-spline collocation algorithms for the numerical solutions of the Coupled Burgers’ equation.

Abstract

Purpose

The purpose of this study is to construct quartic trigonometric tension (QTT) B-spline collocation algorithms for the numerical solutions of the Coupled Burgers’ equation.

Design/methodology/approach

The finite elements method (FEM) is a numerical method for obtaining an approximate solution of partial differential equations (PDEs). The development of high-speed computers enables to development FEM to solve PDEs on both complex domain and complicated boundary conditions. It also provides higher-order approximation which consists of a vector of coefficients multiplied by a set of basis functions. FEM with the B-splines is efficient due both to giving a smaller system of algebraic equations that has lower computational complexity and providing higher-order continuous approximation depending on using the B-splines of high degree.

Findings

The result of the test problems indicates the reliability of the method to get solutions to the CBE. QTT B-spline collocation approach has convergence order 3 in space and order 1 in time. So that nonpolynomial splines provide smooth solutions during the run of the program.

Originality/value

There are few numerical methods build-up using the trigonometric tension spline for solving differential equations. The tension B-spline collocation method is used for finding the solution of Coupled Burgers’ equation.

Details

Engineering Computations, vol. 38 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 July 1943

H.L. Price

The following series of articles presents a new geometrical system of determining the lateral stability of aeroplanes. The method is intended to appeal particularly to engineers…

Abstract

The following series of articles presents a new geometrical system of determining the lateral stability of aeroplanes. The method is intended to appeal particularly to engineers on account of two advantages: it is simple and rapid in operation, and gives a clear insight into the several factors governing the stability. Thus, whereas in the classical method stability calculations entail the drawing and analysis of quartic curves, the results are here obtained, and with greater generality, merely by the use of curves of the second degree. Furthermore, the effects of typical changes in design characteristics may easily be assessed with the minimum of effort. The fundamental analysis is essentially mathematical and follows the treatment first laid down by G. H. Bryan in 1911 and since developed by Bairstow, Glauert, Jones and Bryant. Physical explanations are included where possible to amplify the underlying principles.

Details

Aircraft Engineering and Aerospace Technology, vol. 15 no. 7
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 1 November 1950

S. Neumark

IN high‐speed level flight in the compressibility region an entirely new factor makes its appearance, viz: small variations of atmospheric density and speed of sound with height…

Abstract

IN high‐speed level flight in the compressibility region an entirely new factor makes its appearance, viz: small variations of atmospheric density and speed of sound with height. This factor affects dynamic stability due to continuous changes of height during longitudinal disturbances; there is no effect in lateral disturbances. The affects are very small in low‐speed flight but they increase steadily with Mach number. The short‐period oscillations are not affected but the corrections to phugoid motion become appreciable in high subcritical flight, larger in supercritical (transonic) range, and very important in supersonic flight. The effects of compressibility are of paramount significance but they should be considered in conjunction with varying height effects. Another result of the investigation is the appearance of a new mode of disturbance, due to the stability quartic being converted into a quintic. The fifth (real) root is often small, it may vary in sign according to aerodynamic properties of the aircraft and characteristics of the power unit. The new mode is a subsidence or a divergence, and it determines height stability or instability, hence it may show to what extent an aircraft is able to keep constant altitude over long stretches of time.

Details

Aircraft Engineering and Aerospace Technology, vol. 22 no. 11
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 6 March 2017

HongJun Son, Jonghwan Park, Heecheul Kim, Young Hak Lee and Dae-Jin Kim

This paper aims to propose a generalized finite element technique that can accurately approximate the solution of the flexural-shear cantilever model of wall-frame structures…

Abstract

Purpose

This paper aims to propose a generalized finite element technique that can accurately approximate the solution of the flexural-shear cantilever model of wall-frame structures proposed by Heidebrecht and Stafford Smith.

Design/methodology/approach

This approach adopts scaled monomials as enrichment functions, and they are highly effective in accurately capturing the solution of the problem, as it consists of smooth functions such as polynomials, hyperbolic and trigonometric functions. Several numerical experiments are performed on the static and modal analyses of the flexural-shear cantilever wall-frame structures using the proposed generalized finite element method (GFEM), and their accuracies are compared with those obtained using the standard finite element method.

Findings

The proposed GFEM is able to achieve theoretical convergence rates of the static and modal analyses, which are, in principle, identical to those of the standard FEM, for various polynomial orders of its shape functions such as quadratic, cubic and quartic orders. The proposed GFEM with quartic enrichment functions can provide more accurate solutions than the standard FEM, and thus can be effectively used at the initial design stage of high-rise wall-frame structures.

Originality/value

This work is the first paper where the GFEM is applied to the analysis of high-rise wall-frame structures, and the developed technique can be used as a good analysis tool at the initial design stage.

Details

Engineering Computations, vol. 34 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

Open Access
Article
Publication date: 19 August 2020

Abdelmalek Azizi, Mohamed Talbi and Mohammed Talbi

We determine the Hilbert 2-class field tower for some quartic number fields k whose 2-class group Ck,2 is isomorphic to /2×/2.

Abstract

We determine the Hilbert 2-class field tower for some quartic number fields k whose 2-class group Ck,2 is isomorphic to /2×/2.

Details

Arab Journal of Mathematical Sciences, vol. 27 no. 1
Type: Research Article
ISSN: 1319-5166

Keywords

Article
Publication date: 2 September 2013

In Hyeock (Ian) Lee

Using data from a sample of new high technology manufacturing start-ups in Korea, the purpose of this paper is to examine the multinationality-performance relationship of…

Abstract

Purpose

Using data from a sample of new high technology manufacturing start-ups in Korea, the purpose of this paper is to examine the multinationality-performance relationship of international new ventures (INVs) which are born regional in terms of exporting activities.

Design/methodology/approach

The paper estimates econometric models as both cubic and quartic fits between the degree of multinationality and firm performance of Korean INVs using a feasible generalized least square (FGLS) regression method.

Findings

It is found that the relationship between the INVs' degree of multinationality and firm performance is M-shaped, supporting the augmentation from the traditional S-curve fit applied to multinational enterprises (MNEs). In addition, in terms of performance implications, high technology manufacturing INVs perform better in their home region than in non-home regions when the degree of multinationality is mediocre or becomes very high. Finally, these findings hold for diverse performance measures.

Originality/value

This paper assesses if it is really needed to go beyond the S-shaped curve with a sample of INVs, and how much the addition of the fourth degree polynomial term may increase the empirical model's explained variance between the two model specifications.

Article
Publication date: 12 March 2018

Gianpaolo Savio, Roberto Meneghello and Gianmaria Concheri

This paper aims to propose a consistent approach to geometric modeling of optimized lattice structures for additive manufacturing technologies.

Abstract

Purpose

This paper aims to propose a consistent approach to geometric modeling of optimized lattice structures for additive manufacturing technologies.

Design/methodology/approach

The proposed method applies subdivision surfaces schemes to an automatically defined initial mesh model of an arbitrarily complex lattice structure. The approach has been developed for cubic cells. Considering different aspects, five subdivision schemes have been studied: Mid-Edge, an original scheme proposed by the authors, Doo–Sabin, Catmull–Clark and Bi-Quartic. A generalization to other types of cell has also been proposed.

Findings

The proposed approach allows to obtain consistent and smooth geometric models of optimized lattice structures, overcoming critical issues on complex models highlighted in literature, such as scalability, robustness and automation. Moreover, no sharp edge is obtained, and consequently, stress concentration is reduced, improving static and fatigue resistance of the whole structure.

Originality/value

An original and robust method for modeling optimized lattice structures was proposed, allowing to obtain mesh models suitable for additive manufacturing technologies. The method opens new perspectives in the development of specific computer-aided design tools for additive manufacturing, based on mesh modeling and surface subdivision. These approaches and slicing tools are suitable for parallel computation, therefore allowing the implementation of algorithms dedicated to graphics cards.

Details

Rapid Prototyping Journal, vol. 24 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

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