• Transactions of the Korean Society of Mechanical Engineers
• /
• v.13 no.2
• /
• pp.287-298
• /
• 1989

A numerical work was performed to study the flow behaviors of the open channel type flow with its geometric boundary conditions being similar to that of the Multi-Stage-Flash evaporator with and without a baffle. For the analysis, two-dimensional steady turbulent flow was assumed and the widely known k-.epsilon. turbulence model was usded. SIMPLE algorithm and the power difference scheme were used for the numerical approach. Numerical results generally agree with the previous experimental results though there are some uncertainties at far downstream and near the free surface due to the three dimensionality of the flow and surface waves. Without a baffle, the flow has basically the shape of the submerged plane wall jet with its upper boundary at downstream being sharply curved toward the free surface. For the flow with a baffle, recirculation flow patterns are observed at the upper inlet portion and at the backside of the baffle. For the case without a baffle, it was also confirmed that the ratio between the liquid level and the gate opening height is the most important parameter to determine the flow behavior.

• Archives of Plastic Surgery
• /
• v.36 no.2
• /
• pp.221-224
• /
• 2009

Purpose: The treatment of children mandibular condyle fracture that is severely displaced is controversial. The conservative treatment of it may lead to complications - mandibular deficiency, asymmetry, malocclusion and temporomandibular joint dysfunction. Moreover, open reduction carries risks for growth retardation, facial nerve injury, scarring and joint stiffness. The aim of this article is to present an alternative technique of the treatment by using a threaded Kirschner wire and external rubber traction. Materials: From November 2005 to May 2008, three patients underwent the management by using a threaded Kirschner wire and external rubber traction. A threaded Kirschner wire was inserted in the condylar segment by using a C-arm. We applied the external rubber traction, and we reducted the segment progressively until complete reduction. The mandibular - maxillary fixations were removed after 3 weeks, and patients went into training for mouth opening. Results: The technique didn't result in complications - joint dysfunction, facial nerve injury, sore, infection and nonunion during follow - up period. Radiologic follow - up examinations revealed correct reduction in all patients. In all cases, we found restoration of preinjury occlusion and temporomandibular joint function. Conclusions: Closed reduction of children mandibular condyle fracture by using a threaded Kirschner wire and external rubber traction did achieve anatomic reduction and restore mandibular height. This alternative technique is simple, effective, inexpensive, easy to apply and minimally invasive.

• Journal of Fashion Business
• /
• v.16 no.1
• /
• pp.103-120
• /
• 2012

The study aimed to evaluate the appearance of the men's work clothes jumpers developed to suggest the prototype work clothes jumper patterns by using the 3-D clothing simulation technology. The 3-D simulated clothing images considered the upper body features of men in the age range between 20 and 59 in South Korea. A questionnaire survey conducted previously suggested a basic jumper style with shirt collar and snap opening cuffs for the heavy industry workers; and discomforting parts of the work clothes jumper of the subject workers have been referred to for the experimental jumper appearance test. Besides, defining the measurements of men's upper bodies enabled to generate the men's 3-D virtual models representing each age group's average body feature. The significant body measurement factors for men's 3-D body modeling and jumper pattern-making were stature for the height factor; chest, waist and hip circumferences for the circumference factor; waist back, hip and arm lengths and interscye front/back for the length factor; and back neck breadth for the breadth factor and armscye and scye depths for the depth factor. The men's body measurements of 30's were implemented to three experimental jumper pattern-making methods, i.e. the 1st method using the relations based on stature and chest circumference; the 2nd method using the direct body measurements; and the 3rd method adopting the maximum ease amount of given body measurements whether relations or direct measurements except the direct measurement of scye depth. A comparison among the three experimental jumpers' simulated images highlighted that the appropriate ease amount of the jumper gained higher scores in terms of the jumpers' front, side, back and sleeve parts and the total silhouettes. Therefore the 3rd experimental jumper was finally selected for the heavy industry workers.

• Journal of the Korean Solar Energy Society
• /
• v.29 no.2
• /
• pp.31-38
• /
• 2009

This study was conducted to forecast inner water temperature strata change by extracting deep water from a dam. For the methodology, the scope wherein the balance between the volume of low-temperature water intake through the virtual water intake opening as installed within the stored water area and the volume of water intake from the surrounding area is not destroyed was calculated through the CFD simulation technique using the computational fluid dynamics(CFD) interpretation method. This study suggested a supplementary method(diffuser) to avoid destroying the water temperature strata, and the effect was reviewed. In case of intake of the same volume, when the velocity of flow of water intake is reduced by increasing the pipe diameter, the destruction of water temperature strata can be minimized. When the area(height) where the intake of water is possible is low, a diffuser for interrupting the vertical direction inflow should be installed to secure favorable water intake conditions in case of water intake on the upper part. This study showed that there was no problem if the intake-enabled, low-temperature area was secured approximately 10m from the bottom when the scope that does not destroy the water temperature strata in case of water intake was forecast using the regression formula.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.3
• /
• pp.702-715
• /
• 1990

This paper describes behaviors of two-phase open channel flow inside the flash chamber of a horizontal Multi-Stage-Flash evaporator numerically along with the experimental observations. Bubble trajectories and the velocity and temperature distributions of the liquid phase were predicted by using the particle-source-in-cell(PSI-Cell) method with the appropriate bubble motion/growth equations. Size and number of bubble nuclei embedded in the incoming liquid(brine) were taken into account as important parameters in addition to the conventional ones such as the velocity, degree of inlet superheat, inlet opening height, and the liquid level. Bubble motions, which are unsteady, appeared to be mostly determined by the buoyancy and the drag forces. The calculations, though a number of simplifying assumptions were made, reasonably simulated the hydrodynamic behaviors of the two-phase horizontal stream observed in the experiments. The simulated temperature distributions also agreed fairly well with the other's measurements. Non-equilibrium allownaces, evaluated from the simulated temperature distributions, were within the range of those obtained from the existing correlations, and reduced with the increases of the number and size of incoming bubble nuclei due to vigorous flashing.

• Journal of Ocean Engineering and Technology
• /
• v.30 no.6
• /
• pp.505-519
• /
• 2016

If the seabed is exposed to high waves for a long period, the pore water pressure may be excessive, making the seabed subject to liquefaction. As the water pressure change due to wave action is transmitted to the pore water pressure of the seabed, a phase difference will occur because of the fluid resistance from water permeability. Thus, the effective stress of the seabed will be decreased. If a composite breakwater or other structure with large wave reflection is installed over the seabed, a partial standing wave field is formed, and thus larger wave loading is directly transmitted to the seabed, which considerably influences its stability. To analyze the 3-D dynamic response characteristics of the seabed around a composite breakwater, this study performed a numerical simulation by applying LES-WASS-3D to directly analyze the wave-structure-soil interaction. First, the waveform around the composite breakwater and the pore water pressure in the seabed and rubble mound were compared and verified using the results of existing experiments. In addition, the characteristics of the wave field were analyzed around the composite breakwater, where there was an opening under different incident wave conditions. To analyze the effect of the changed wave field on the 3-D dynamic response of the seabed, the correlation between the wave height distribution and pore water pressure distribution of the seabed was investigated. Finally, the numerical results for the perpendicular phase difference of the pore water pressure were aggregated to understand the characteristics of the 3-D dynamic response of the seabed around the composite breakwater in relation to the water-structure-soil interaction.

• Korean Journal of Environment and Ecology
• /
• v.20 no.2
• /
• pp.227-234
• /
• 2006

The comparison of Corylopsis coreana populations between natural groups and deforestation groups is carried in five regions such as Seungju, Woldeung, Hwangjeon in Suncheon, Myeongseok in Jinju and Mt. Baegun in Pocheon. The number of sprouting per both $100m^2$ and each individual stump were appeared more in deforestation than in natural groups. In contrast, the height and the diameter of individuals by the number of sprouting are higher and larger in the natural groups. The relationship between the floristic composition and vegetation in the two groups of C. coreana populations was not appeared. Corylopsis coreana are propagated sprouting as well as seedling in deforestation groups located an opening area. Because of the powerful environmental adaptability through growth of the sprouting and the seedling in deforestation groups, the population of C. coreana are not extinction of species oneself, and on the contrary are showed expansion of C. coreana population after temporary disturbance.

• Environmental Analysis Health and Toxicology
• /
• v.27
• /
• pp.12.1-12.8
• /
• 2012

Objectives: The aim of this study was to identify the health and environmental risk factors of air contaminants that influence environmental and respiratory diseases in Gyeongju, Pohang and Ulsan in South Korea, with a focus on volatile organic compounds (VOCs). Methods: Samples were collected by instantaneous negative pressure by opening the injection valve in the canister at a fixed height of 1 to 1.5 m. The sample that was condensed in $-150^{\circ}C$ was heated to $180^{\circ}C$ in sample pre-concentration trap using a 6-port switching valve and it was injected to a gas chromatography column. The injection quantity of samples was precisely controlled using an electronic flow controller equipped in the gas chromatography-mass spectrometer. Results: The quantity of the VOC emissions in the industrial area was 1.5 to 2 times higher than that in the non-industrial area. With regards to the aromatic hydrocarbons, toluene was detected at the highest level of 22.01 ppb in Ulsan, and chloroform was the halogenated hydrocarbons with the highest level of 10.19 ppb in Pohang. The emission of toluene was shown to be very important, as it accounted for more than 30% of the total aromatic hydrocarbon concentration. Conclusions: It was considered that benzene in terms of the cancer-causing grade standard, toluene in terms of the emission quantity, and chloroform and styrene in terms of their grades and emission quantities should be selected for priority measurement substances.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.5
• /
• pp.783-788
• /
• 2002

Recently, research and developmental direction of communication system is concurrent adopting voice data and face image in speaking to provide more higher recognition rate then in the case of only voice data. Therefore, we present a method of lipreading in speech image sequence by using the 3-D facial shape model. The method use a feature information of the face image such as the opening-level of lip, the movement of jaw, and the projection height of lip. At first, we adjust the 3-D face model to speeching face Image sequence. Then, to get a feature information we compute variance quantity from adjusted 3-D shape model of image sequence and use the variance quality of the adjusted 3-D model as recognition parameters. We use the intensity inclination values which obtaining from the variance in 3-D feature points as the separation of recognition units from the sequential image. After then, we use discrete HMM algorithm at recognition process, depending on multiple observation sequence which considers the variance of 3-D feature point fully. As a result of recognition experiment with the 8 Korean vowels and 2 Korean consonants, we have about 80% of recognition rate for the plosives md vowels.

• Fire Science and Engineering
• /
• v.32 no.6
• /
• pp.7-14
• /
• 2018

This study investigated numerically the influences of fire curtain and natural smoke vent area on smoke movement in the stage fire of a theater using FDS (Fire Dynamics Simulator). The dimension of the theater stage was 31 m in width, 34 m in depth, and 32 m in height. The area ratios between the natural smoke vent and stage were approximately 10%, 8%, 5%, and 1%. The gap distance between the fire curtain and proscenium wall was 0.5 m. The fire curtain and natural smoke vent area were observed to affect significantly the behavior of smoke movement to the auditorium and the mass flow rates of inflow and outflow through the natural smoke vent and proscenium opening. In addition, under the same natural smoke vent area, the pressure in the stage with a fire curtain was lower than that without a fire curtain.