• Computers and Concrete
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• 제5권5호
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• pp.449-459
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• 2008

This paper focuses on the application of two dimensional orthogonal polynomials in the regression analysis for the relationship of product parameters viz. compressive strength, bulk density and water absorption of fly ash cement bricks with other process parameters such as percentages of fly ash, sand and cement. The method has been validated by linear and non-linear two parameter regression models. The use of two dimensional orthogonal system makes the analysis computationally efficient, simple and straight forward. Corresponding co-efficient of determination and F-test are also reported to show the efficacy and reliability of the relationships. By applying the evolved relationships, the product parameters of fly ash cement bricks may be approximated for the use in construction sectors.

• 한국유체기계학회 논문집
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• 제2권1호
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• pp.50-55
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• 1999

The performance of a centrifugal fan depends on the dimensional parameters of impeller, such as the inlet and exit diameter, area ratio, relative flow angles to the blade, and the number of blades. These design parameters, however, are inter-related, so it is very difficult to identify the effect of each parameter on the fan performance. In this experimental study the effects of the design parameters on the performance of a small centrifugal impeller being used for vacuum cleaners are investigated. A total of 30 shrouded impellers with 120mm diameter were tested and the results were non-dimensionalized to compare their performance.

• Structural Engineering and Mechanics
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• 제44권5호
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• pp.681-704
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• 2012

The dynamic response of Euler-Bernoulli beams to resonant harmonic moving loads is analysed. The non-dimensional form of the motion equation of a beam crossed by a moving harmonic load is solved through a perturbation technique based on a two-scale temporal expansion, which permits a straightforward interpretation of the analytical solution. The dynamic response is expressed through a harmonic function slowly modulated in time, and the maximum dynamic response is identified with the maximum of the slow-varying amplitude. In case of ideal Euler-Bernoulli beams with elastic rotational springs at the support points, starting from analytical expressions for eigenfunctions, closed form solutions for the time-history of the dynamic response and for its maximum value are provided. Two dynamic factors are discussed: the Dynamic Amplification Factor, function of the non-dimensional speed parameter and of the structural damping ratio, and the Transition Deamplification Factor, function of the sole ratio between the two non-dimensional parameters. The influence of the involved parameters on the dynamic amplification is discussed within a general framework. The proposed procedure appears effective also in assessing the maximum response of real bridges characterized by numerically-estimated mode shapes, without requiring burdensome step-by-step dynamic analyses.

• 한방비만학회지
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• 제23권1호
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• pp.28-41
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• 2023

Objectives: This study was aimed to evaluate the hemodynamic feasibility using pulse parameters as a way to establish safe dose guidelines for herbal prescription containing Ephedra herb (Ephedra intermedia Schrenk & C.A.Mey) on weight loss, and to provide a foundation for developing evidence-based guidelines for clinical use. Methods: Forty-two volunteers were recruited to participate in a study examining the changes in pulse wave characteristics following the ingestion of Gambi-hwan, a herbal prescription containing ephedra, over a period of 4 weeks, and pulse wave measurements were taken before and after the administration. Pulse wave parameters were measured in this study using a 3-dimensional radial pulse tonometry device (DMP-Lifeplus). In addition, questionnaire, blood pressure, temperature, and body composition were also measured as secondary measures. Results: Fifteen minutes after administration of Gambi-hwan, the non-adverse event group (non-AE) exhibited a statistically significant increase in several power and pressure-related parameters, including h1, h5, systolic area, pulse area, and pulse width, while the AE group showed a trend of decreasing stroke volume and increasing Radial Augmentation Index (RAI), w, and w/t. After 4 weeks of administration, both groups exhibited significant changes in pulse rate, w/t, RAI, t3/t, stroke volume (SV), and stroke volume Index (SVI). Notably, there are significant differences between AE group and non-AE group in w/t, SV, and SVI. Conclusions: These findings suggest that pulse parameters may be a useful way to establish safe dosing guidelines for weight loss herbal prescription containing ephedra. Further research is needed to confirm these results and to develop evidence-based guidelines for clinical use.

• 대한융합한의학회지
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• 제6권1호
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• pp.5-20
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• 2024

Objectives: This study was aimed to evaluate the hemodynamic feasibility using pulse parameters as a way to establish safe dose guidelines for Chunwangbosim-dan, and to provide a foundation for developing evidence-based guidelines for clinical use. Methods: Forty-one volunteers were recruited to participate in a study examining the changes in pulse wave characteristics following the ingestion of Chunwangbosim-dan, over a period of 2 weeks, and pulse wave measurements were taken before and after the administration. Pulse wave parameters were measured in this study using a 3-dimensional radial pulse tonometry device(DMP-Lifeplus). In addition, questionnaire, blood pressure, temperature, and body composition were also measured as secondary measures. Results: Fifteen minutes after administration of Chunwangbosim-dan, the non-adverse event group(non-AE) exhibited a statistically significant increase in several power and pressure-related parameters, including h1, h3, h4, h5, SA, PA and PW, while the adverse event group(AE) showed a trend of decreasing stroke volume and increasing Systemic Vascular Resistance Index(SVRI) and applied pressure. After 2 weeks of administration, non-adverse event group(non-AE) exhibited significant changes in standard deviation of pulse rate and HRV_LH ratio. Notably, there are significant differences between AE group and non-AE group in h4/h1, w/t, applied pressure, SV and pulse rate. Conclusion: These findings suggest that pulse parameters may be a useful way to establish safe dosing guidelines for Chunwangbosim-dan. Further research is needed to confirm these results and to develop evidence-based guidelines for clinical use.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.180-183
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• 2003

In this research, on-line model for prediction of effective strain distribution hi strip on finishing mill process is prescribed. It has been developed using several selected non-dimensional parameters and previously made average effective strain model via series of finite element process simulations, $\Delta$$\varepsilon$ was introduced to describe the effective strain distribution in strip. To confirm adequate non-dimensional variables uniqueness test was done. And to decide the order of polynomial in on-line model equation tendency test for each variables was done. The prediction accuracy of the proposed model is examined through comparison with finite element calculation results.

• 대한기계학회논문집B
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• 제36권9호
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• pp.907-913
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• 2012

연속적으로 누출되면서 원형으로 퍼져가고 있는 액체에 대한 모델에 대한 고차 섭동 해를 구하여 1차 섭동 해를 개선하였다. 일반적인 해를 얻기 위하여 무차원화된 지배방정식을 유도하고 무차원 지배 변수를 도출하였다. 무차원 증발계수를 섭동 변수로 이용하였다. 계산 결과 부피 및 확산 반경에 관해서 고차 섭동해가 1차 섭동 해를 개선시키고 있으며, 섭동해의 차수가 증가함 따라 오차를 감소시키는 경향을 보였다. 3차 섭동 해는 수치 해와 거의 일치하고 있어 3차 섭동해의 타당성을 보여주고 있다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.1054-1059
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• 2002

A linearly tapered beam immersed partially in other material is considered and is modelled as a linearly tapered Bernoulli-Euler beam fixed at the bottom with a concentrated mass at the top. Its governing equations is derived and its free vibration analysis is performed for various boundary conditions. And the rotatory inertia of the eccentric lumped tip mass is considered. The problem of determining the natural frequencies leads to an eighth order determinant. The solutions of the frequency equations are obtained numerically. The non-dimensional frequency parameters are given in tabular form and the influence of non-dimensional parameters on natural frequency is discussed for various conditions.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.27-32
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• 2005

This paper investigates the effects of outdoor pressure fluctuations on natural ventilation through openings of a building envelope. The ventilation airflow rate depends on the magnitude and the period of the pressure fluctuations, the size of the opening compared to the space volume, and the resistance characteristics of the opening. Non-dimensional parameters have been derived, which determine indoor pressure responses due to outdoor pressure fluctuations. The flow regions are categorized into synchronized region, opening resistance region, and transition region depending on the non-dimensional parameters.

• Journal of the Korean Physical Society
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• 제73권11호
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• pp.1612-1618
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• 2018

In this work, the ground-state properties of an interacting electron gas confined in a two-dimensional quantum dot system with the Gaussian potential ${\upsilon}(r)=V_0(1-{\exp}(-r^2/p))$, where $V_0$ and p are confinement parameters, are determined numerically by using the Thomas-Fermi approximation. The shape of the potential is modified by changing the $V_0$ and the p values, and the influence of the confining potential on the system's properties, such as the chemical energy, the density profile, the kinetic energy, the confining energy, etc., is analyzed for both the non-interacting and the interacting cases. The results are compared with those calculated for a harmonic potential, and excellent agreement is obtained in the limit of high p values for both the non-interacting and the interacting cases.