• Journal of Electrochemical Science and Technology
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• 제8권3호
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• pp.244-249
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• 2017

This paper presents the results of an investigation into the isoamperic point of cyclic voltammograms, which is defined as the singular point where the voltammograms of various scan rates converge. The origin of the unique point is first considered from a theoretical perspective by formulating the voltammetric curves as a system of linear equations, the solution of which indicates that a trivial solution is only available at the potential at which the net current is zero during the reverse potential scan. In addition, by way of a mathematical formulation, it was also shown that the isoamperic point is dependent on the switching potential of the potential scanning. To validate these findings, theoretical and practical cyclic voltammmograms were studied using finite-element based digital simulations and 3-electrode cell experiments. The new understanding of the nature of the isoamperic point provides an opportunity to measure the charge transfer effects without the influence of the mass transfer effects when determining the thermodynamic and kinetic characteristics of a faradaic system.

• 제어로봇시스템학회논문지
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• 제13권3호
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• pp.210-217
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• 2007

The theoretical formulations are derived for calculating optical power change for intensity modulated fiber optical microphone. The optical power change is due to optical paths, misalignment and geometry of optical coupler. Based on the theoretical equations, three different optical couplers are simulated with respect to several angles of optical couplers. In order to evaluate the formulation, a multi-mode to multi-mode coupler which is one of abovementioned optical couplers is designed and characterized by carving out both static experiments and dynamic experiments. Considering experimental results, this paper conclude that the theoretical formulations is very useful for design optical coupler and this kind of fiber optic sensor is adequate to microphone.

• 한국생산제조학회지
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• 제20권3호
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• pp.225-231
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• 2011

In this paper, a new end-milling force modelling technique was suggested by considering runout, and its result was compared with real measured force. The specific cutting force is the multiplication of cutting force coefficient and uncut chip thickness. This parameter was used for experimental modelling and prediction of theoretical force. These coefficients, which can be obtained by fitting measured average forces in several conditions, were used for the formulation of theoretical force. The mechanism of end-milling force with runout was developed in this research and its result was verified by comparing the fluctuating theoretical force and its measured one. The fluctuation of force was incurred by a geometric shape of workpiece and its runout in holding. The result of suggested force considering runout shows a good consistency with measured one. So this modelling method can be used effectively for a prediction of end-milling force with runout effect.

• Wind and Structures
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• 제10권2호
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• pp.177-208
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• 2007

Few mathematical methods attracted theoretical and applied researches, both in the scientific and humanist fields, as the Proper Orthogonal Decomposition (POD) made throughout the last century. However, most of these fields often developed POD in autonomous ways and with different names, discovering more and more times what other scholars already knew in different sectors. This situation originated a broad band of methods and applications, whose collation requires working out a comprehensive viewpoint on the representation problem for random quantities. Based on these premises, this paper provides and discusses the theoretical foundations of POD in a homogeneous framework, emphasising the link between its general position and formulation and its prevalent use in wind engineering. Referring to this framework, some applications recently developed at the University of Genoa are shown and revised. General remarks and some prospects are finally drawn.

• Structural Engineering and Mechanics
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• 제82권2호
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• pp.191-204
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• 2022

A three-mass vehicle model including one rigid mass and two unsprung masses is adopted to predict the vehicle-bridge interaction (VBI) and to establish the nonlinear coupled governing equations. To overcome the numerical instability and large computation problems concerning the vehicle-bridge system, the perturbation method is used to convert the nonlinear coupled governing equations into a set of linear uncoupled equations. Formulas for bridge's natural frequencies considering both the VBI and the dynamic responses of bridge and vehicle are proposed. Compared with the numerical results obtained by the Newmark-β method, the theoretical solutions for natural frequencies and dynamic responses are validated. The effects of the important factors of unsprung mass, vehicle damping, surface irregularity on the natural frequencies and dynamic responses of bridge and vehicle are discussed, based on the theoretical solutions.

• Journal of applied mathematics & informatics
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• 제41권4호
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• pp.723-739
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• 2023

In this paper, we developed three theoretical models based on prey and predator that exhibit holling-type response functions. In both a fuzzy and a crisp environment, we have provided a mathematical formulation for the prey predator concept. We used the signed distance method to defuzzify the triangular fuzzy numbers using the alpha-cut function. We can identify equilibrium points for all three theoretical models using the defuzzification technique. Utilizing a variational matrix, stability is also performed with the two species model through three theoretical models. Results are presented, followed by discussion. MATLAB software is used to provide numerical simulations.

• Journal of Theoretical and Applied Mechanics
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• 제3권1호
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• pp.66-80
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• 2002

The bilinear formulation proposed earlier by Peters and Izadpanah to develop finite elements in time to solve undamped linear systems, Is extended (and found to be readily amenable) to develop time finite elements to obtain transient responses of both linear and nonlinear, and damped and undamped systems. The formulation Is used in the h-, p- and hp-versions. The resulting linear and nonlinear algebraic equations are differentiated to obtain the first- and second-order sensitivities of the transient response with respect to various system parameters. The present developments were tested on a series of linear and nonlinear examples and were found to yield, when compared with results obtained using other methods, excellent results for both the transient response and Its sensitivity to system parameters. Mostly. the results were obtained using the Legendre polynomials as basis functions, though. in some cases other orthogonal polynomials namely. the Hermite. the Chebyshev, and integrated Legendre polynomials were also employed (but to no great advantage). A key advantage of the time finite element method, and the one often overlooked in its past applications, is the ease In which the sensitivity of the transient response with respect to various system parameters can be obtained. The results of sensitivity analysis can be used for approximate schemes for efficient solution of design optimization problems. Also. the results can be applied to gradient-based parameter identification schemes.

• Journal of Advanced Marine Engineering and Technology
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• 제20권2호
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• pp.75-75
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• 1996

The rapid expansion for the auto-industry and the worldwide trend toward non-asbestos friction materials for brake lining force our industry to transfer into non-asbestos ones from asbestos-based friction materials. Furthermore, it is imperative for the friction materials to have technological excellence and lower production cost to be competitive in the world market. There is no known theoretical procedures to formulate friction materials. It, rather, depends on the trial and error process. Thus, it is quite clear how important it is to accumulate the know-how on the formulation and manufacturing the friction material. This study concerns the practical ways of conceptualizing the formulation and optimizing the manufacturing process. This study focused on the development of formulation for non-asbestos friction material as well as deriving the physical properties of the trial product to prove its validity and applicability. Elaboration of the formula and optimizing scheme of the manufacturing process to get better quality are also sought. Physical properties were obtained by constant velocity test dynamotest, hardness test and strength test. Differential scanning calorimeter was also used to analyze the thermal reactions of organic constituents, microstructures, bond effects, and degree of mixture.

• Journal of Advanced Marine Engineering and Technology
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• 제20권2호
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• pp.7-14
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• 1996

The rapid expansion for the auto-industry and the worldwide trend toward non-asbestos friction materials for brake lining force our industry to transfer into non-asbestos ones from asbestos-based friction materials. Furthermore, it is imperative for the friction materials to have technological excellence and lower production cost to be competitive in the world market. There is no known theoretical procedures to formulate friction materials. It, rather, depends on the trial and error process. Thus, it is quite clear how important it is to accumulate the know-how on the formulation and manufacturing the friction material. This study concerns the practical ways of conceptualizing the formulation and optimizing the manufacturing process. This study focused on the development of formulation for non-asbestos friction material as well as deriving the physical properties of the trial product to prove its validity and applicability. Elaboration of the formula and optimizing scheme of the manufacturing process to get better quality are also sought. Physical properties were obtained by constant velocity test dynamotest, hardness test and strength test. Differential scanning calorimeter was also used to analyze the thermal reactions of organic constituents, microstructures, bond effects, and degree of mixture.

• 대한조선학회논문집
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• 제36권2호
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• pp.77-93
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• 1999

본 연구에서는 충격횡압력을 받는 선체 판부재의 붕괴강도 특성을 분석하고 충격하중 효과를 고려한 간이 구조설계식을 제시하고자 한다. 충격횡압력하에 판부재의 붕괴거동을 분석하기 위해 기존의 실험결과와 더불어 범용 비선형 유한요소해석 프로그램인 STARDYNE을 이용하였다. 이론적 방법으로는 먼저 강소성이론을 이용하여 정적 횡압력을 받는 판부재에 대한 붕괴강도식을 도출하였다. 또한, 변형률속도 효과를 고려하여 충격 횡압력 문제에도 적용하였다. 실제 판부재에 적용 예로써 충격횡압력을 받는 강판부재와 알루미늄합금 보강판부재에 대한 붕괴거동을 분석하였다.