• 한국입자에어로졸학회지
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• 제18권4호
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• pp.97-107
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• 2022

The geometry of popular wave plate type mist eliminator for the wet flue gas desulfurization process was improved, fabricated, and experimentally evaluated. A Mist eliminator is a type of inertial particle collector which collection efficiency is proportional to the velocity of the gas phase. However, as the amount of re-entrainment is also proportional to the gas phase velocity, there is a limitation for the gas phase flow rate. Re-entrainment is one of the most important issues in a mist eliminator and is likely to occur as the input of the liquid phase and flow rate of the gas phase increase. In order to resolve this problem, the projection angle of the improved mist eliminator is set to 30° from the conventional one while maintaining the cross-section. With low flow rate conditions, the modified mist eliminator showed a similar pressure drop and overall collection efficiency. However, with conditions in which re-entrainment is obviously occurring, the modified mist eliminator showed better performance in draining droplets than the conventional one. As a result, the modified mist eliminator showed higher overall collection efficiency.

• Current Optics and Photonics
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• 제8권3호
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• pp.259-269
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• 2024

Optical imaging systems that operate through atmospheric pathways often suffer from image degradation, mainly caused by the distortion of light waves due to turbulence in the atmosphere. Adaptive optics technology can be used to correct the image distortion caused by atmospheric disturbances. However, there are challenges in conducting experiments with strong atmospheric conditions. An optical phase plate (OPP) is a device that can simulate real atmospheric conditions in a lab setting. We suggest a novel two-step process to fabricate an OPP capable of simulating the effects of atmospheric turbulence. The proposed fabrication method simplifies the process by eliminating additional activities such as phase-screen design and phase simulation. This enables an efficient and economical fabrication of the OPP. We conducted our analysis using the statistical fluctuations of the refractive index and applied modal expansion using Kolmogorov's theory. The experiment aims to fabricate an OPP with parameters D/r₀ ≈ 30 and r₀ ≈ 5 cm. The objective is defined with the strong atmospheric conditions. Finally, we have fabricated an OPP that satisfied the desired objectives. The OPP closely simulate turbulence to real atmospheric conditions.

• 소음진동
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• 제9권3호
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• pp.509-516
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• 1999

The ESPI (Electronic Speckle Pattern Interferometry) algorithm has been simulated to calculate vibrational modes of a thin right-angled STS304 plate. The phase transformation of the reference wave of the ESPI is carried out only one time during vibration in order to clarify ESPI speckle patterns. Two dimensional vibrational modes are calculated from one ESPI pattern before vibration onset and two ESPI patterns during vibrations but with and without the phase transformation. The ESPI harmonic results are compared with those derived from the finite element method (FEM), and they agree very well. Additionally a phase unwrapping algorithm has been newly developed to derive a displacement map from an ESPI phase map.

• 소음진동
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• 제10권6호
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• pp.949-954
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• 2000

Applicability of the vibration signal phase for predicting the modal damping properties of structures is investigated. For uniform plates with different internal damping levels, the phase delay as a function of the frequency span as well as a function of the distance between the excitation and response measurement points are experimentally obtained. Dependence of the phase characteristics on the amount of structural damping is elucidated -more heavily damped plate shows notably reduced phase delay at intermediate distances. The experimental results compare favorably with analytical predictions, and show much promise for further refinement as a tool for estimating structural properties.

• 한국안전학회지
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• 제8권2호
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• pp.44-50
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• 1993

The objective of this study was to investigate the extraction of chromium(Vl) ion in waste water through the liquid surfactant membrane with open-type Perforated Reciprocating-Plate Column. Extraction experiments were conducted to measure the effect of flow characteristics of continuous and dispersed phase and stroke velocity, sodium hydroxide concentraction in internal aqueous phase, sulfuric acid concentraction in outer phase, and residence time distribution and measured extraction velocity. The result of experiments showed that extraction velocity of chromium ion was maximum when stroke velocity was 180 1/min and dispersion phase velocity was 30m11min, continuous phase velocity was 20m1/min. Extraction velocity of chromium ion increased with increasing difference of hydrogen ion concentraction of dispersion and continuous phase and column stage decreased.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1306-1311
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• 2004

The performance test apparatus of liquid-phase plate heat exchanger was installed and the computer program for design was developed in this study. The detail temperature distribution of hot and cold fluids in each path of heat exchanger was calculated by numerical method and the correlation for the heat transfer coefficient was defined. The heat transfer coefficients were measured using the working fluids of water and glycerine to investigate the effect of fluid viscosity. The measured heat transfer coefficients were compared with the calculated values obtained from the computer program and it was shown that error of the calculated values was generally less than 5%.

• Steel and Composite Structures
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• 제35권3호
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• pp.343-351
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• 2020

The present research deals with the multi-dual-phase-lags thermoelasticity theory for thermoelastic behavior of transversely isotropic thermoelastic thin circular plate The Laplace and Hankel transform techniques have been used to find the solution of the problem. The displacement components, stress components, and conductive temperature distribution are computed in the transformed domain with the radial distance and further determined in the physical domain using numerical inversion techniques. The effect of rotation and two temperature are depicted graphically on the resulting quantities.

• 한국군사과학기술학회지
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• 제14권6호
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• pp.1171-1177
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• 2011

A high power laser beam focused on a small area accelerates a thin material that flies and hits other target material in which a shock wave may be induced. This laser induced shock experimental method is more repeatable and cheaper but worse than other experimental method using gas gun or other apparatus. An optical system including a phase zone plate reduces the interference and also makes the focused-beam-intensity distribution uniform. We wrote a computer code that calculates light ray traces. Using the code we designed and fabricated an optical system including a phase zone plate and improved the laser-beam uniformity. We introduce preliminary experimental results of laser induced shock of the samples such as aluminum and other materials.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제21권2호
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• pp.131-138
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• 1999

The purpose of this study is to evaluate the effects of resorbable plate in the healing process of mandibular fracture. Reduction and rigid fixation was carried out on the artificial mandibular fracture site of the rabbits, using a resorbable screw, 1.5mm in diameter and 4.0mm in length, and an absorbable plate 1.5mm in thickness(Lactosorb$^{(R)}$). En block tissue specimens with plate were taken from the rabbits at 4, 6, 8, and 10 weeks intervals and specimen were observed with light microscope under the hematoxylin-eosin staining, to observe the inflammatory reaction and tissue healing process. The following conclusions were drawn: 1. The subject displayed good healing with no signs of detachment of the fixation plate. 2. At 4 weeks, the plate was covered by the connective tissue. Then at 6 weeks, bone regeneration was discovered around the plate. 3. During the period of healing, no inflammatory reaction or foreign body reaction, as a result of using resorbable plate, were observed. 4. At 8 weeks, the initial phase of the absorption of the plate was observed. Then at 10 weeks, macrophage were observed around the plate, indicating the absorption phase was in process. From the above results, it can be determined that when the resorbable plate is applied to rabbit, full recuperation occurs naturally in the absence of inflammatory reaction and foreign body reaction. The selected study is clinically valuable in proving this procedure.

• 한국산학기술학회논문지
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• 제12권6호
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• pp.2470-2476
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• 2011

실험적인 방법과 수치적인 방법의 장점을 취한 고유변형도법은 선상가열에 의한 판의 변형을 예측하는데 매우 유용하다. 고유변형도법을 이용한 선상가열에 의한 판 변형의 예측을 위해서는 고유변형도의 크기와 영역을 적절하게 결정하는 것이 중요한데, 선상가열 후의 실제 냉각속도에 따라 강의 상변태 특성이 달라지므로 이 또한 고유변형도 결정에 있어서 고려되어야 한다. 조선 현장에서 많이 사용되는 수냉과정을 모사하기 위해 충돌제트, 막비등, 복사 효과를 포함하는 열전달 해석법을 제안하였으며, 이를 통해 고유변형도 영역의 실제 냉각속도와 상변태 분율을 구할 수 있다. 상변태 분율에 따른 재료의 물성치를 반영함으로써 선상가열에 의한 판의 변형을 보다 정도 있게 예측하는 것이 가능하다.