• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1891-1895
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• 2008

Water covers 70% of the earth's surface and the human body consist of 75% of it. It is clear that water is one of the prime elements responsible for life on earth. Over the last 30 years or so, numerous studies have attempted to find out more about the water microscopically. In this paper, we investigated how the receding and advancing contact angle of the moving water droplet changes on a solid surface having various LJ epsilon parameters. To observe the dynamic contact angle history, a body force applied to all water molecules after obtained the water droplet in equilibrium with the solid surface. We obtained the density profile and receding and advancing contact angle of the moving water droplet

• 상하수도학회지
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• 제36권5호
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• pp.261-273
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• 2022

In this study, we collect water control valves that have had accidents due to existing cracks, etc. are collected, and propose investigation items for strengthening the valve structural safety evaluation through a series of analyzes from valve specifications to physicochemical properties are proposed. The results of this study are as follows. First, there was a large variation in the thickness of the body or flange of the valves to be investigated, which is considered to be very important factor, because it may affect the safety of the valve body against internal pressure and the flange connected with the bolt nut. Second, 60% of the valves under investigation had many voids in the valve body and flange, etc. and the decrease in thickness due to corrosion was relatively large on the inner surface in contact with water rather than the outer surface. It is judged that the investigation of depth included voids is very important factor. Third, all valves to be investigated are made of gray cast iron foam, and therefore it is judged that there is no major problem in chemical composition. It is judged that the chemical composition should be investigated. Fourth, as a physical investigation item, the analysis of metal morphology structure seems to be a very important factor for nodular cast iron from rather than a gray cast iron foam water valve with a flake structure. As it was found to be 46.7~68.8% of the standard recommended by KS, it could have a direct effect on damage such as cracks, and therefore it is judged that the evaluation of tensile strength is very important in evaluating the safety of the valve.

• 한국전산유체공학회지
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• 제20권2호
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• pp.103-108
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• 2015

Fluid-body interaction analysis of floating body with six degree-of-freedom motion is presented. In this study, three-dimensional incompressible Navier-Stokes equations are employed as a governing equation. The numerical method is based on a finite-volume approach on a cartesian grid together with a fractional-step method. To represent the body motion, the immersed boundary method for direct forcing is employed. In order to simulate the coupled six degree-of-freedom motion, Euler's equations based on rigid body dynamics are utilized. To represent the complex body shape, level-set based algorithm is utilized. In order to describe the free surface motion, the volume of fluid method utilizing the tangent of hyperbola for interface capturing scheme is employed. This study showed three different continuums(air, water and body) are simultaneously simulated by newly developed code. To demonstrate the applicability of the current approach, two different problems(dam-breaking with stationary obstacle and water entry) are simulated and all results are validated.

• 동의생리병리학회지
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• 제34권4호
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• pp.209-214
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• 2020

The association of cold-heat (CH) pattern and anthropometry/body composition has been suggested in that they are related to thermoregulation. We aimed to study the association of CH pattern and anthropometry/body composition. A total of 1479 individuals aged 50-80 years were included in the study, and their CH pattern were evaluated by a self-administered questionnaire. After adjustment for age and sex, the CH score were significantly correlated with weight, BMI (body mass index), body surface area, waist-hip ratio, fat free mass, body fat mass, body cell mass, intracellular water, extracellular water, and basal metabolic rate; however, the correlation coefficients were mostly low (0.15-0.24). The selected variables for predicting CH score were various according to the methods used for variable selection; however, the adjusted R-squared of the final models were all around 0.12. Thus the most parsimonious model could be the one that includes sex and BMI. In conclusion, various anthropometry and body composition indices were associated with CH pattern. Future studies are necessary to improve the performance of the prediction model.

• Fisheries and Aquatic Sciences
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• 제19권5호
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• pp.23.1-23.7
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• 2016

The effects of daily feeding frequency (Exp I), water temperature (Exp II), and stocking density (Exp III) on the growth of river puffer, Takifugu obscurus, juvenile fish of 10 and 40 g in body weight were examined to develop effective techniques to produce river puffer in a non-exchange water system. In Exp I, fish were fed commercial floating feed with 45 % protein one to five times per day to apparent satiation each by hand daily for 8 weeks at $25^{\circ}C$. In both the 10- and 40-g size groups, the final body weight, daily feed consumption, and weight gain of fish fed one meal per day were significantly lower than those of fish fed five meals per day (P < 0.05). However, there were no significant differences in the final body weight, daily feed consumption, and weight gain among fish fed two, three, and five meals per day. Feed efficiency showed decreasing tendency with increasing size of fish. In Exp II, fish of 10 and 40 g in initial body weight were reared with the commercial feed at $15-30^{\circ}C$ for 8 weeks. The weight gain of fish increased with raising water temperature up to $25^{\circ}C$ and decreased drastically at $30^{\circ}C$ for both sizes. The Q10 of specific growth rate was decreased with raising water temperature from 5.04 (temperature interval, $15-20^{\circ}C$) to 0.66 ($25-30^{\circ}C$) for the 10-g fish and from 4.98 to 0.31 for the 40-g fish. In Exp III, the effect of stocking density on growth was examined with fish of 10 and 40 g in initial body weight. The final body weight for initial stocking densities of 4, 8, and $12kg/m^3$ was significantly higher than that of $20kg/m^3$ for the 10-g fish, and the final stocking density reached 10.1, 19.2, 28.7, and $39.9kg/m^3$, respectively. For the 40-g fish, the final body weight for initial stocking densities of 3 and $6kg/m^3$ was significantly higher than that of 9 and $15kg/m^3$ and the final stocking density reached 7.38, 13.5, 17.1, and $27.5kg/m^3$, respectively (P < 0.05). In both groups, weight gain tended to decrease with increasing stocking density; however, survival showed no significant difference.

• Biomolecules & Therapeutics
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• 제11권3호
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• pp.200-203
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• 2003

The present study was carried out to investigate the potential acute toxicity of bamboo leaf water extract by a single oral dose in Sprague-Dawley rats. Twenty male and female rats aged 5 weeks were randomly assigned to four groups of 5 rats each and were administered singly by gavage at dose levels of 0, 1250, 2500, or 5000 mg/kg body weight. Mortalities, clinical findings, and body weight changes were monitored for the l4-day period following the administration. At the end of 14-day observation period, all animals were sacrificed and complete gross postmortem examinations were performed. Throughout the study period, no treatment-related deaths were observed. There were no adverse effects on clinical signs, body weight, and gross finding at any dose tested. The results showed that the single oral administration of bamboo leaf water extract did not induce any toxic effect at a dose level of below 5000 mg/kg in rats and that the minimal lethal dose were considered to be over 5000 mg/kg body weight for both sexes.

• 한국가시화정보학회지
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• 제18권3호
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• pp.61-68
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• 2020

Thermographic phosphor (TP) thermometry is a noncontact optical measurement method and has been applied in many fields such as combustion and heat transfer. However, due to the limitation of bonding technology and measurement method, most TP thermometry studies were conducted only on the air environment with water-soluble binders. In this paper, a temperature measurement technology in water using TP is proposed by coatings of manganese activated magnesium fluorogermanate (Mg4FGeO6:Mn4+, MFG) with Polydimethylsiloxane (PDMS). Four MFG-PDMS coatings with different thicknesses were prepared. The lifetime of MFG was not affected by the thickness of the coating as a result of the experiment and analysis of phosphor intensity using a photomultiplier tube. To measure the surface temperature field of an immerged body in water, a cylinder-type cartridge heater was coated with MFG doped PDMS. Transient surface temperature field was successfully measured even the initial temperature is higher than the boiling point of water.

• 대한약침학회지
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• 제10권3호
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• pp.149-155
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• 2007

Objectives The purpose of this study is aimed at diagnosing and suggesting treatment plans for commonly seen clinical manifestation of heat symptom in the upper body and coldness in the lower body, also known as hot above, cold below syndrome. Methods Various reasons attribute to the presence of hot above, cold below syndrome, but mainly contributed by blockage of normal Qi flow by abnormality of heart-kidney root, spleen-stomach axis, and liver-lung axis. Diagnosing these abnormalities and timely alleviation to the healthy state is presented in the study. Results 1For heat in the upper body, Huang Lian Jie Du Tang(黃連解毒湯), CF, or JsD pharmacopuctures are injected on GB21, GB20. Qi stagnation in the thoracic area is treated with BUM injection on CV17. For impairment of transportation and transformation in the middle energizer, BUM pharmacopuncture is injected on CV12. Coldness in the lower energizer was relieved by bee venom or Sweet BV(Bee Venom free from enzymes) on CV6. Conclusion Above proposed methods of regulating water-fire were effective in treating hot above, cold below syndrome in clinical manifestations. But once the symptom subsides, treatment focused on eliminating innate cause should be rendered to achieve more successful results.

• International Journal of Fluid Machinery and Systems
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• 제9권1호
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• pp.47-55
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• 2016

The portable hydraulic turbine we previously developed for open channels comprises an axial flow runner with an appended collection device and a diffuser section. The output power of this hydraulic turbine was improved by catching and accelerating an open-channel water flow using the kinetic energy of the water. This study aimed to further improve the performance of the hydraulic turbine. Using numerical analysis, we examined the performances and flow fields of a single runner and a composite body consisting of the runner and collection device by varying the airfoil and number of blades. Consequently, the maximum values of input power coefficient of the Runner D composite body with two blades (which adopts the MEL031 airfoil and alters the blade angle) are equivalent to those of the composite body with two blades (MEL021 airfoil). We found that the Runner D composite body has the highest turbine efficiency and thus the largest power coefficient. Furthermore, the performance of the Runner D composite body calculated from the numerical analysis was verified experimentally in an open-channel water flow test.

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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• pp.3183-3188
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• 2015

Objective: This study aimed to evaluate the prevalence of skin lesions, which is a health effect of chronic arsenic (As) exposure, and determine the hair/blood arsenic concentrations of people living in Kutahya villages who are using and drinking tap water with a high concentration of arsenic. Materials and Methods: A total of 303 people were included in the present cross-sectional study. A prepared questionnaire form was used to collect the participants' information and environmental history. Skin examination was performed on all participants. Hair, blood and water samples were analyzed using atomic absorption spectroscopy. The cumulative arsenic index (CAI) was calculated for all participants. Results: Villages were divided into two groups according to the arsenic level (<$20{\mu}g/L$, Group I; >$20{\mu}g/L$, Group II) in their water. The prevalence of skin lesions, hair and blood arsenic level, and CAI were found to be higher in the Group II participants. There was a positive association between body arsenic levels and CAI in the participants of each group. Conclusions: The number of skin lesions and arsenic concentrations in body samples were found to increase with the water arsenic level and exposure time. We hope that sharing this study's results with local administrators will help accelerate the rehabilitation of water sources in Kutahya.