• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.11
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• pp.1570-1577
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• 2002

In order to investigate the characteristics of two-phase slug flow, an electromagnetic flowmeter with 240Hz triangular AC excitation was designed and manufactured. The signals and noise from the flowmeter were obtained, and analyzed in comparison with the observations with a high speed CCD camera. The uncertainty of the flowmeter under single-phase flow was $\pm$ 2.24% in real-time. For two-phase slug flow, electromagnetic flowmeter provided real-time simultaneous measurements of the mean film velocity around Taylor bubble and the relative location and the length of the bubble. Besides, it is an easier and cheaper method for measuring mean film velocity than others such as photochromic dye activation method or particle image velocimetry.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.1
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• pp.79-83
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• 2004

This study was how to control the mass flow controller in gas supplying system. The flow controller consists of piezoelectric material and sensor with heating wire. It is difficult to obtain accurate model, because MFC was composed of many parts, and the relationship between input and output of controller is nonlinear. The model for control was obtained by time constant and DC gain Based on this model, PID controller was applied to flow controller using DSP board. Also, the results were compared to controller using system identification.

• Korean journal of food and cookery science
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• v.20 no.3
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• pp.292-298
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• 2004

This study researched the microbial change of quality according to various phases of product flow of Dongtae-Jeon (a pan-fried dish) and rolled egg in packaged meals. In order to carry out the study, the time required, temperature, water activity and microbial quality were measured at various phases of production flow of Dongtae-Jeon and rolled egg in packaged meals, and the effects of these factors on microbial multiplication was analyzed. According to the phases in product flow of Dongtae-Jeon, it was shown that the time required is 12.5hrs and water activity is distributed 0.932-0.980. These conditions were suitable for microbial multiplication. According to the phases in product flow of rolled egg, it was shown that the time required is 3.3hrs. In addition, qualitative analysis of pathogenic microorganisms (Salmonella spp., Vibrio parahaemolyticus, Staphylococcus aureus) detected no such microorganisms in any of the samples.

• Electrical & Electronic Materials
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• v.7 no.3
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• pp.206-212
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• 1994

In this paper, We discuss the $POCI_3$ doping process according to the variation of deposition temperature, gas flow rate and doping time. The factors acted with $POCI_3$ doping are gas flow rate deposition temperature and time etc. Among them the temperature is the most important factor. For the $POCI_3$ flow rate, it should not exceed the resistivity saturation point developed on poly surface by annealing treatment. Therefore, this study suggests the optimum conditions of Poly-silicon treatments with the $POCI_3$ flow rate.

• The Journal of Korea Robotics Society
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• v.5 no.2
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• pp.85-92
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• 2010

In this paper, we propose a digital image stabilization technique using edge detection and Lucas-Kanade optical flow in order to minimize the motion of the shaken image. The accuracy of motion estimation based on block matching technique depends on the size of search window, which results in long calculation time. Therefore it is not applicable to real-time system. In addition, since the size of vector depends on that of block, it is difficult to estimate the motion which is bigger than the block size. The proposed method extracts the trust region using edge detection, to estimate the motion of some critical points in trust region based on Lucas-Kanade optical flow algorithm. The experimental results show that the proposed method stabilizes the shaking of motion image effectively in real time.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.11
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• pp.864-872
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• 2002

In this study, the effect of planform curvature on the stability of coupled flow/structure vibration is examined in transonic and supersonic flow regions. The aeroelastic analysis for the frequency and time domain is performed to obtain the flutter solution. The doublet lattice method(DLM) in subsonic flow is used to calculate unsteady aerodynamics in the frequency domain. For all speed range, the time domain nonlinear unsteady transonic small disturbance code has been incorporated into the coupled-time integration aeroelastic analysis (CTIA). Two curved wings with experimental data have been considered in this paper MSC/NASTRAN is used for natural free vibration analyses of wing models. Predicted flutter dynamic pressures and frequencies are compared with experimental data in subsonic and transonic flow regions.

• Journal of Environmental Science International
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• v.20 no.1
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• pp.107-118
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• 2011

While the assessment of mean flow field is very important to characterize the hydrodynamic aspect of the flow regime in river, the conventional methodologies have required very time-consuming efforts and cost to obtain the mean flow field. The paper provides an efficient technique to quickly assess mean flow field by developing and applying spatial averaging method utilizing repeatedly surveyed acoustic Doppler current profiler(ADCP)'s cross-sectional measurements. ADCP has been widely used in measuring the detailed velocity and discharge in the last two decades. In order to validate the proposed spatial averaging method, the averaged velocity filed using the spatial averaging was compared with the bench-mark data computed by the time-averaging of the consistent fix-point ADCP measurement, which has been known as a valid but a bit inefficient way to obtain mean velocity field. The comparison showed a good agreement between two methods, which indicates that the spatial averaging method is able to be used as a surrogate way to assess the mean flow field. Bed shear stress distribution, which is a derived hydrodynamic quantity from the mean velocity field, was additionally computed by using both spatial and time-averaging methods, and they were compared each other so as to validate the spatial averaging method. This comparison also gave a good agreement. Therefore, such comparisons proved the validity of the spatial averaging to quickly assess mean flow field. The mean velocity field and its derived riverine quantities can be actively used for characterizing the flow dynamics as well as potentially applicable for validating numerical simulations.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.161-166
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• 2003

It is the common features of the integral reactors that the main components of the RCS are installed within the reactor vessel, and so there are no any flow pipes connecting the coolant pumps or steam generators. Due to no any flow pipes, it is impossible to measure the differential pressure at the RCS of the integral reactors, and it also makes impossible measure the flow-rate of the reactor coolant. As a alternative method, the method by the measurement of coolant pump power has been introduced in this study. Up to now, we did not found out a precedent which the coolant pump power is used for the real-time flow-rate calculation at normal operation of the commercial nuclear power plants. The objective of the study is to embody the real-time flow-rate calculation method by the measurement of coolant pump power in an integral reactor. As a result of the study, we could theoretically reason that the capacity-head curve and capacity-shaft power curve around the rated capacity with the high specific-speeded axial flow pumps have each diagonally steep incline but show the similar shape. Also, we could confirm the above theoretical reasoning from the measured result of the pump motor inputs, So, it has been concluded that it is possible to calculate the real-time flow-rate by the measurement of pump motor inputs. In addition, the compensation for a above new method can be made by HBM being now used in the commercial nuclear power plants.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.44
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• pp.135-151
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• 1997

In this paper, we propose a simple and relatively efficient heuristic method to determine job sequencing in the flow-shop considering multiple criteria such as processing time, due date and cost. The proposed method is applicable to the flow- shop where the jobs are released simultaneously and their processing sequence is predetermined and not changed until the whole jobs are processed. To develop this method, we mixed and modified some well-known multi-attribute decision heuristics such as the simple linear weighting scheme, the lexicographic rule and the 'elimination by aspect' rule. Some computer simulations were conducted to test the efficiency of the proposed method and it has been compared with the SWPT (Shortest Working Processing Time) rule and EDD (Earliest Due Date) rule. The results show that our method is as effective as the traditional ones in terms of mean flow time, tardiness, makespan, cycle time, machine utilization, etc., and proved to be much simpler and more flexible to be used in real situations.

• 한국전산유체공학회:학술대회논문집
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• 2000.05a
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• pp.78-83
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• 2000

An iterative time marching procedure for solving incompressible internal flow has been applied to the flow around a rotor-stator. This procedure solves three-dimensional incompressible Reynolds-averaged Navier-Stokes equation on a moving, time-deforming, non-orthogonal body-fitted grid using second-order accurate schemes for the time derivatives and third/second-order accurate schemes for the spatial derivatives. To handle rotationg geometry, the multiblock technique is applied and the overall flow domain is subdivided into two blocks. In each block, a grid is generated and flowfield is solved independently of the other blocks. The boundary data for each block is provided by the neighboring blocks using bilinear interpolation technique.