• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.26 no.2
• /
• pp.63-81
• /
• 2021

In this study, we investigated the tide-induced flow patterns near the ocean outfall of the Jeju and Bomok Wastewater Treatment Plants (WTP) in Jeju Island by using measurements of Acoustic Doppler Current Meter (ADCP) and a numerical experiment with inserting passive tracer into a regional ocean model. In late spring of 2018, the ADCP measurements showed that tidal currents dominate the flow patterns as compared to the non-tidal components in the outfall regions. According to harmonic analysis, the dominant type of tides is mixed of diurnal and semi-diurnal but predominantly semidiurnal, showing stronger oscillations in the Jeju WTP than those in the Bomok WTP. The tidal currents oscillate parallel to the isobath in both regions, but the rotating direction is different each other: an anti-clockwise direction in the Jeju WTP and a clockwise in the Bomok WTP. Of particular interest is the finding that the residual current mainly flows toward the coastline across the isobath, especially at the outfall of the Bomok WTP. Our model successfully captures the features of tidal currents observed near the outfall in both regions and indicates possibly high persistent pollutant accumulation along the coasts of Bomok.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.27 no.5
• /
• pp.509-519
• /
• 2013

Through the study on judgment of Body form and settle Energy flow(立形定氣) before diagnose the patients, the results are as follows. The observation of the body form is to determine prosperity and deficiency of each internal organ. It is necessary to distinguish Body form loss(形脫) and Body form fullness(形充). Fat man(肥人), Thin man(瘦人), Creamy man(膏人), Muscular man(肉人), Small Fat man(脂人) are discriminated by fat distribution, fat content, and muscle mass. The observation of the body form means the observation of structure disorder, color change, develop part at body, head and face. The observation of the body form that is to determine prosperity and deficiency of each internal organ is from the limited knowledge of the anatomy. The observation of face color is considered by blood perfusion, blood oxygenation and accumulation of carotinoid, bilirubin and change of melanin in the facial skin. The prosperity and the deficiency of energy flow is considered by symptom combined with growth (<40 years) and aging (>40 years). The prosperity of energy flow includes the anger, anxious emotion and the deficiency of energy flow includes the fear, depressive emotion. The breathing type is expiratory exhalation like asthma patients in the prosperity of energy flow. The deficiency of energy flow is weakness to overcome the disease. The prosperity and the deficiency of energy flow are considered by body metabolic ratios (Basal metabolic Rate: BMR, Resting metabolic rate: RMR, Physical activity ratios: PASs). Development of subcutaneous fat is good in the person of prosperous energy flow. The person of prosperous energy flow is hard to overcome to heat weather than cold weather. The person of deficiency of energy flow has tendencies of low blood pressure, insufficiency of blood flow in the peripheral and being shocked. The person of deficiency of energy flow has tendencies of chronic fatigue syndrome or automatic nerve disorder. If the patient who has deficiency of energy flow has severe weight loss should be checked for the presence of disease. The observation of small and large of bone is to check the development and disorder of bone growth and aging. The observation of thickness and weakness of muscle is to check the development of muscle, particularly biceps, gastrocnemius, and rectus abdominal muscle. The observation of thickness and weakness of skin is to check the ability of regulating body temperature by sweating.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.40 no.11
• /
• pp.689-695
• /
• 2016

The performance of proton exchange membrane fuel cells (PEMFC) is strongly related to the water flow and accumulation in the gas diffusion layer (GDL) and catalyst layer. Understanding the behavior of fluid from the characteristics of the media is crucial for the improvement of the performance and design of the GDL. In this paper, a numerical method is proposed to calculate the design parameters of the GDL, i.e., permeability, tortuosity, and effective diffusivity. The fluid flow in a channel filled with randomly packed hard spheres is simulated to validate the method. The flow simulation was performed by lattice Boltzmann method with bounce back condition for the solid volume fraction in the porous media, with different values of porosities. Permeability, which affects the flow, was calculated from the average pressure drop and the velocity in the porous media. Tortuosity, calculated by the ratio the average path length of the randomly injected massless particles to the thickness of the porous media, and the resultant effective diffusivity were in good agreement with the theoretical model. The suggested method can be used to calculate the parameters of real GDL accurately without any modification.

• Journal of Oral Medicine and Pain
• /
• v.25 no.4
• /
• pp.345-353
• /
• 2000

This study was to investigate normal salivary flow rates and normal indices of Quantitative analysis of salivary scintigraphy. 96 adult volunteers were studied by Questionnaire evaluating salivary conditions and clinical examinations. 35(male 23, female 12, age range 23-31years) that absented subjective and objective symptoms related saliva were classified as normal group. The normal group underwent measurement unstimulated and stimulated salivary flow rates and salivary scintigraphy. The obtained results were as follows: 1. There were not significant in sex differences of unstimulated and stimulated salivary flow rates. The unstimulated salivary flow rate was $0.66{\pm}0.41g/min$, stimulated salivary flow rates was $1.61{\pm}0.69g/min$. 2. As comparing of parameters of salivary scintigraphy, the Uptake ratio(UR), $T_{max}$, $T_{min}$, Maximum accumulation (MA), Maximum secretion(MS) of parotid and submandibular glands were not significant in sex and side-ralated differences. 3. The UR, $T_{max}$, MA, MS of parotid gland were significantly higher than those of submandibular gland; in the parotid gland, UR, $3.67{\pm}0.88$, $T_{max}$, $18.77{\pm}0.43min$, MA, $41.35{\pm}9.22%$, MS, $43.13{\pm}9.13%$; in the submandibular gland, UR, $3.04{\pm}0.10$, $T_{max}$, $18.48{\pm}0.52min$, MA, $36.47{\pm}14.18%$, MS, $36.88{\pm}12.20%$. 4. As classifying of time-activity curve, the most of parotid gland was N-type(97.1%), submandibular gland was observed in order of M-type(67.1%), N-type(21.4%), F-type(11.4%), however, was not observed S-type. 5. As the type of time-activity curve of submandibular gland was more flattened, the UR, $T_{max}$, MA, MS were significantly decresed.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.5
• /
• pp.629-639
• /
• 2002

In-vitro flow characteristics downstream of a polyurethane artificial heart valve and a Bjork-Shiley Monostrut mechanical valve have been comparatively investigated in pulsatile flow using particle image velocimetry (PIV). With a triggering system and a time-delayed circuit the velocity distributions on the two perpendicular measurement planes downstream of the valves are evaluated at any given instant in conjunction with the opening behaviors of valve leaflets during a cardiac cycle. The regions of stasis and high shear stress can be found simultaneously by examining the entire view of the instantaneous velocity and Reynolds shear stress fields. It is known that high shear stress regions exist at the interface between strong axial jet flows along the wall and vortical flows in the central area distal to the valves. In addition. there are large stagnation or recirculation regions in the vicinity of the valve leaflet, where thrombus formation can be induced by accumulation of blood elements damaged in the high shear stress zones. A correlation between the unsteady flow patterns downstream of the valve and the corresponding opening postures of the polyurethane valve membrane gives useful data necessary for improved design of the frame structure and leaflet geometry of the polyurethane valve.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.7 no.1
• /
• pp.1-12
• /
• 2004

The summer distribution of $Cha-{alpha}$ and physical processes for simulating outbreak region of red tide were estimated by the Eco-Hydrodynamic model in Chinhae Bay. As a result of simulation of surface residual currents, the southward flow come in contact with the northward flow at the inlet and western part of bay in case of windlessness and below wind velocity 2 m/sec. As wind velocity increases, the velocity and direction of currents were fairly shifted. The predicted concentration of $Cha-{alpha}$ exceeded 20 mg/㎥ in Masan and Haengam Bays, and most regions were over 10 mg/㎥, which meant the possibility of red tide outbreak. From the results of the contributed physical processes to $Cha-{alpha}$, accumulation sites were distributed at the northern part of Kadok channel, around the Chilcheon island, the western part of Kajo island and some area of Chindong Bay. On the other hand, inner parts of the study area such as Masan Bay were estimated as the sites of strong algal activities. Masan and Haengam Bay are considered as the initial outbreak region of red tide by the modeling and observed data, and then red tide expanded to other areas such as physical accumulation region and western inner bay, as depending on environmental variation. The increase of wind velocity led to decrease of $Cha-{alpha}$ and enlargement of accumulation region. The variation of intensity of radiation and sunshine duration caused to rapidly fluctuation of $Cha-{alpha}$: however, it was not largely affected by the variation of pollutant loads from the land only.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.12
• /
• pp.453-458
• /
• 2016

While the design of weirs requires a scour-considered strategy, research on the analysis of the effectiveness of hydraulic energy dissipaters and design criteria are scarce due to the limited experimental facilities and restraint in the experiment conduction period. The study analyzed the scour dissipation effect of multidirectional dissipaters to improve the scour problems of a weir downstream and suggests design criteria to minimize scour. A hydraulic model experiment was conducted for Nakdong River Hapcheon-Changnyeong Weir and a model in 1/25 of horizontal accumulation and 1/25 of vertical accumulation was produced. The experimental equipment was classified into channels and a flow rate supply and an underwater pump were installed to enable flow at a maximum of 2.0 m3/s. The experimental inflow was 1.3 m3/s, the upstream water level was 0.36 m, downstream water level was 0.24 m, and a cylinder wooden baffle, a dissipater, with a diameter of 0.05 m was made. A 3D scanner was also used for an accurate scour depth comparison for a length change of the baffle before and after installing the baffle. When the baffle was arranged in the shape of a V, the depth of scour decreased by 36% while the scour length decreased by 49% due to flow reduction compared to that before installing the baffle.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.23 no.3
• /
• pp.220-235
• /
• 2020

Heat wave generation in cities is basically affected by global warming, but it is further exacerbated by the impact of artificial heat emission and heat accumulation in the city. In particular, the effects of urban heat waves directly affect the occurrence of tropical nights. Basically, however, the choice of countermeasures against tropical nights is very limited compared to the daytime heat wave response. The purpose of this study was to analyze the characteristics of cold air flow at night as a countermeasure against tropical nights in Daegu Metropolitan City and to suggest its spatial applicability. As a research method, the spatial characteristics (flow velocity, flow rate, flow direction and range) of cold air flow in Daegu were quantitatively analyzed using KLAM_21, a cold air flow analysis program. As a result of the analysis, it was found that cold air generation and flow in the surrounding mountains of Daegu Metropolitan City was very active, but the inflow was limited to the urban area, which has tropical nights. However, it has been shown that the flow of cold air flowing from the surrounding mountains is very active in some urban areas, so it has spatial conditions that are very effective in countering tropical nights. If these spatial conditions are used for the urban planning, it will be very useful to develop countermeasures for tropical nights.

• KCID journal
• /
• v.18 no.2
• /
• pp.87-100
• /
• 2011

This study is to delineate the watershed hydrological parameters such as area, slope, rain gauge weight, NRCS-CN and time of concentration (Tc) by using the Geographic Information Sytem (GIS) technique, and estimation of design flood for an ungauged watershed. Especially, we attempted to determine the Tc of ungauged watershed and develop simple program using the cell-based algorithm to calculates upstream or downstream flow time along a flow path for each cell. For a $19km^2$ watershed of tributary of Nakdong river (Seupmoon), the parameters including flow direction, flow accumulation, watershed boundary, stream network and Tc map were extracted from 30m Agreeburn DEM (Digital Elevation Model) and landcover map. And NRCS-CN was extracted from 30m landcover map and soil map. Design rainfall estimation for two rainfall gauge which are Sunsan and Jangcheon using FARD2006 that developed by National Institute for Disaster Prevention (NIDP). Using the parameters as input data of HEC-l model, the design flood was estimated by applying Clark unit hydrograph method. The results showed that the design flood of 50 year frequency of this study was $8m^3/sec$ less than that of the previous fundamental plan in 1994. The value difference came from the different application of watershed parameter, different rainfall distribution (Huff quartile vs. Mononobe) and critical durations. We could infer that the GIS-based parameter preparation is more reasonable than the previous hand-made extraction of watershed parameters.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.29 no.12 s.243
• /
• pp.1291-1298
• /
• 2005

Since the interior shape of a pressure regulator is complex and the change of fluid resistance at each operation condition is rapid and big, the pressure regulator can become the major factor that causes big loss in pipelines. So the suitable pressure regulator modeling by each operation condition is important to obtain reliable results especially in small scale pipeline network analysis. And in order to prevent the condensation and freezing problems, it is needed to confirm both whether temperature recovery is achieved after passing by the pressure regulator's narrow neck and how much amount of low temperature area that can cause condensate accumulation is distributed by various PCV models at every inlet-outlet pressure ratio. In this research, the numerical model resembling P company pressure regulator that is used widely for high pressure range in commercial, is adopted as the base model of CFD analysis to investigate pressure regulator's flow characteristics at each pressure ratio. Additionally it is also introduced to examine pressure regulator's critical flow characteristics and possibility of condensation or freezing at each pressure ratio. Furthermore, the comparison between the results of CFD analysis and the results of analytic solution obtained by compressible fluid-dynamics theory is attempted to validate the results of CFD modeling in this study and to estimate the accuracy of theoretical approach at each pressure ratio too.