• 한국수학사학회지
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• 제26권5_6호
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• pp.371-388
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• 2013

In ${\ll}$The Method${\gg}$, Archimedes presented the famous heuristic technique for calculating areas, volumes and centers of gravity of various plane and solid figures, utilizing the law of the lever. In that treatise, Archimedes used the fact that the center of gravity of a cone lies one-quarter of the way from the center of the base to the vertex, but the proof of this is not extant in his works. This study analyzes the propositions and their relations of ${\ll}$The Method${\gg}$ focusing on the procedural characteristics of the 'method' of Archimedes. According to the result of that analysis, this study discusses the likely approach which was taken for Archimedes to find out the center of gravity of a cone.

• 한국수학사학회지
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• 제23권4호
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• pp.47-58
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• 2010

이 연구에서는 고대 수학자 아르키메데스의 '방법'에 대한 새로운 해석을 제시한다. 이를 위해, 우선 그 '방법'의 해석과 관련된 핵심 쟁점을 살펴보고 논쟁의 중심에 불가분량과 지레의 원리가 있지만 그 사이의 관계가 규명되지 않았음을 확인한다. 그리고 아르키메데스의 신중한 불가분량 사용에 대해 수학사에 근거한 탐색적 추측활동을 수행함으로써, 아르키메데스 '방법'에 있어 지레의 원리의 핵심적 역할이 변화율의 통제라는 가설을 제안한다.

• 한국가시화정보학회지
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• 제11권1호
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• pp.28-33
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• 2013

This paper describes aerodynamic characteristics of an Archimedes spiral wind turbine with various angles of attack. The range of angles was controlled from $-30^{\circ}$ (clockwise) to $+30^{\circ}$ (clockwise). The rotating speed of wind turbine at the same angle of attack in both directions was different. The reason why the-maximum rotational speed was observed at $15^{\circ}$ in clockwise direction can be explained based on angular momentum conservation. Quantitative flow visualization around Archimedes wind turbine blade was carried out between $-15^{\circ}$ (clockwise) and $+15^{\circ}$ (counter clockwise) using high resolution PIV method. The relationship between drag force and rotating speeds was discussed. From these results, optimum design on yawing system of Archimedes spiral wind turbine may provide high efficiency on small wind power system.

• 상하수도학회지
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• 제23권6호
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• pp.865-870
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• 2009

In this study, the adequacy of Reynolds numbers and Froude numbers derived from about sixty domestic water treatment plants (WTPs) were analyzed in order to estimate the characteristics of hydraulic behavior within the rectangular shaped sedimentation basins used widely. From the results of analysis, most of domestic WTPs have satisfied the criteria regulated as that Reynolds number should less than 1,000(dimensionless). On the other hand, they have not been able to satisfy the Froude number criteria, which should be higher than $1.0{\times}10^{-6}$. The reasons why most of domestic WTPs could not satisfy the criteria are that its criteria basis has been not only inadequate, but also the concept of external flow occurred around a settling particle has been ignored. Accordingly, this study proved the feasibility of Archimedes number, which indicates the ratio between particle Reynolds number and Froude number, to evaluate the hydraulic efficiency and its function of scale factor.

• 한국수학사학회지
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• 제27권4호
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• pp.271-283
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• 2014

This study takes a look at Polya's analysis on Archimedes' "The Method" from a math-historical perspective. We, based on the elaboration of Polya's analysis, investigate the analytic geometric characteristics of Archimedes' "The Method" and discuss the way of using the characteristics in education of school calculus. So this study brings up the educational need of approach of teaching the definite integral by clearly disclosing the transition from length, area, volume etc into the length as an area function under a curve. And this study suggests the approach of teaching both merit and deficiency of the indivisibles method, and the educational necessity of making students realizing that the strength of analytic geometry lies in overcoming deficiency of the indivisibles method by dealing with the relation of variation and rate of change by means of algebraic expression and graph.

• 한국수학사학회지
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• 제19권3호
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• pp.95-112
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• 2006

본 논문은 고대 수학자이며 발명가인 아르키메데스의 ${\ll}$구와 원기둥에 관하여${\gg}$ 에 대해 고찰한다. 3차원의 공간기하학에 관한 ${\ll}$구와 원기둥에 관하여${\gg}$ 에 제시되어 있는 명제들을 통하여 고대 수학자가 어떻게 입체도형을 수학적으로 정복하였으며 이런 고대 수학적 아이디어가 어떻게 현대의 적분개념으로 발달하게 되었는지를 알아보는 것은 현대 수학에 대한 이해를 깊이 있게 함과 동시에 새로운 수학적 아이디어의 개발에 좋은 소재가 될 것으로 기대한다.

• 한국초전도ㆍ저온공학회논문지
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• 제25권3호
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• pp.18-21
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• 2023

Pollution of the environment by micro-plastics is now a worldwide problem. Plastics are difficult to decompose and put a great load on the marine environment. Especially a plastic with a size of 5 mm or less is defined as micro-plastic and are carried by ocean currents over long distances, causing global pollution. These are not easily decomposed in the natural environment. In this paper, we aimed to experimentally demonstrate that micro-plastics in seawater can be continuously separated by electromagnetic Archimedes force. Using polyethylene particles of 3 mm in diameter as the separation target, a flow channel was fabricated and separation conditions were investigated by particle trajectory calculations for separation experiments. Based on the calculation results, a solenoid-type superconducting magnet was used as a source of magnetic field to conduct separation experiments of micro-plastics in seawater. Although a high separation rate was assumed in the simulation results, the experimental results did not show any significant improvement in the separation rate due to the electromagnetic Archimedes force. It was found that the gas generated by the electrolytic reaction may have inhibited the migration of the particles.

• 한국과학교육학회지
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• 제33권1호
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• pp.30-45
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• 2013

이 연구에서는 과학자의 창의성이 발현되는 과정을 분석할 수 있는 모델을 개발하고, 이를 사용하여 Archimedes의 왕관 문제를 해결하는 사고과정을 분석하였다. 그 결과 복잡해 보이는 과학자의 문제해결과정을 반복적이며 순환적인 모델로 표현할 수 있으며, Archimedes의 사례를 통해 과학자의 창의성에서 요구되었던 다양한 사고의 융합 과정을 분석할 수 있었다. 이 연구에서는 또한 과학자들의 창의적인 발견에서 실험의 역할을 제시하였으며, 과학교과서의 시각이 과학사적인 사실과 다른 이유에 대해서도 고찰해 보았다. 그리고 창의적 사고과정에서 귀추적 추론과 사전 지식의 중요성도 언급하였다. Archimedes는 역학이라는 사고판과 목욕이라는 일상의 사고판이 교차를 이루면서 왕관의 문제를 창의적으로 해결했다. 이 과정에서 귀추적 추론 과정과 사전 지식이 중요한 역할을 했다. Archimedes의 사례 이외에도 우리가 교과서를 통해 다루는 다양한 과학자들의 창의적인 발견 과정을 재구성할 수 있다면, 이러한 과정을 학생들이 경험하도록 교육의 단계를 제공함으로서 학생들이 창의적 사고 능력을 키워나갈 수 있을 것이다.

• 한국수학교육학회지시리즈A:수학교육
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• 제47권1호
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• pp.1-10
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• 2008

Some of school mathematics contents that have deep mathematical meanings are regarded as obvious and their importance is frequently overlooked. We first reexamined the mathematical meaning of pi as a constant. Then we indicated the educational implications of Archimedes' calculation method of pi and finally underlined the availability of pi as a valuable research topic in school mathematics.

• 한국초전도ㆍ저온공학회논문지
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• 제18권1호
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• pp.14-18
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• 2016

Organic compounds have a problem that the separation of structural isomer in the preparation process requires high energy consumption. This study proposes a new separation method of structural isomer using Magneto- Archimedes method. Firstly, the levitation height of 1, 6-DDA and 1, 10-DDA was respectively calculated by simulation of the forces acting on the particles under magnetic field, and it was indicated that they could be separated by the difference of levitation height. To confirm the phenomenon experimentally, white powders of 1, 6-DDA and 1, 10-DDA were formed into pellets, and were soaked in manganese chloride solution. Then the solution was put on the center of the cryostat of HTS bulk magnet (maximum magnetic flux density is 3T). As a result, it was confirmed that the separation of structural isomer by difference of levitation height could be possible.