• Journal of Korea Water Resources Association
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• v.50 no.12
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• pp.877-887
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• 2017

The energy losses due to surcharged flow at four-way combining manhole, which is mainly installed in the downstream of urban sewer system, is the main cause of inundation in urban area. Surcharged four-way combining manholes form various flow configuration such as straight through, T-type, and four-way manholes depending on variation of inflow discharge in inlet pipes. Therefore, it is necessary to analyze change of energy loss and estimate head loss coefficients at surcharged four-way combining manhole with variation of inflow discharge ratio. The hydraulic experimental apparatus which can change inflow ratios were installed to analyze the flow characteristics at four-way combining manhole. In this study, to calculate the head loss coefficient according to change of the inflow discharge ratios at the surcharged four-way combining square manhole, the discharge conditions of 40 cases which the inflow ratios of each inlet pipe were changed by 10% interval was selected. The head loss coefficient at surcharged square manhole showed the lowest value of 0.40 at the straight manhole and the highest value of 1.58 at the $90^{\circ}$ junction manhole. In the combining manholes (T-type and four-way), the head loss coefficients were calculated more higher as the lateral flow rate was biased. The contour map of head loss coefficient range was constructed by using the estimated head loss coefficients and the empirical formula of head loss coefficients was derived to consider the variation of inflow discharge ratios at the surcharged square manhole. The empirical formula could be applied to the design and assessment of the urban drainage system.

• Journal of the Korea Concrete Institute
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• v.26 no.6
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• pp.731-739
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• 2014

This paper describes the evaluation of the impact performance of steel fiber-reinforced concrete based on high-velocity impact experiments using hard spherical balls. In this experimental study, panel specimens with panel thickness to ball diameter (h/d) ratios of 3.5 or less were tested with variables of steel fiber volume fraction, panel thickness, impact velocity, and aggregate size. Test results were compared with each other to evaluate the impact resistance. The results showed that the percentage of weight and surface loss decreased as the steel volume fraction increased. However, the penetration depth increased with up to steel fiber volume fraction of 1.5%. Particularly the results of specimens with 20 mm aggregates showed poorer performance than those with 8 mm aggregates. The results also confirmed that the impact performance prediction formulas are conservative with (h/d) ratios of 3.5 or less. Despite the conservative predictions, the modified NDRC formula and ACE formula predict the impact performance more consistently than the Hughes formula.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.6
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• pp.532-539
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• 2008

Kwon et al.(2008) carried out a hydraulic experiment in order to evaluate Manning coefficient, which implicates flow resistance due to bottom friction as well as drag caused by the squared piers higher than water depth and arranged with equal intervals, under the flow condition with a constant drag coefficient, $Re>10^4$. And, based on the equation of equilibrium, they proposed a formula for the equivalent resistant coefficient including empirical drag interaction coefficient obtained by using the experimental results. In this study, the hydraulic experiment was simulated using FLOW-3D, a 3-dimensional computational fluid dynamic code. The computations were compared with the experiment results as well as the semi-theoretical formula, and the comparisons show a good agreement. From the agreement, it was confirmed that when flow resistance bodies were higher than water depth, Manning n value increases with 2/3 power of water depth as shown in the theoretical formula and that drag interaction coefficient was dominated by their intervals.

• Korean Journal of Adult Nursing
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• v.13 no.3
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• pp.373-384
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• 2001

The purpose of this study was to develop a DanJeon Breathing Exercise Program for health promotion and to examine the effects of a DanJeon Breathing Exercise Program on the physical and emotional health promotion of women in midlife. The design utilized for this study was quasi-experimental with a nonequivalent control group pretest-posttest design. This study was done between February 1 and July 4, 2000 and the subjects of the study were 40 women in midlife living in Seoul. There were 20 members in experimental group who participated in the DanJeon Breathing Exercise Program and 20 members in the control group who were chosen as matched to members of the experimental group according to age, education and religion. The DanJeon Breathing Exercise Program was carried out for 80 minutes a day, 3 times a week for 12 weeks. The percent of body fat, back strength, flexibility (trunk flexion), balance and vital capacity were measured using the Health Management System developed by the Korea Physical Science Institution. Blood tests were done at D infirmary for total cholesterol, and the atherogenic index was calculated using an established formula. The scores of anxiety and depression were measured by a questionnaire with 10 questions on anxiety and 13 questions on depression. It was developed from the Korean Manual of Symptoms-Checklist-90 revision. The collected data were processed using the SPSS PC program and analyzed using $\chi^2$-test and t-test. The result of this study are as follows : 1. The percent of body fat for the experimental group who participated in the DanJeon Breathing Exercise Program was lower than that of the control group. 2. The degree of back strength, flexibility (trunk flexion) and balance of the experimental group that participated in the DanJeon Breathing Exercise Program was higher than that of the control group. 3. The vital capacity of the experimental group that participated in the DanJeon Breathing Exercise Program was higher than that of the control group. 4. The total cholesterol level and atherogenic index of the experimental group that participated in the DanJeon Breathing Exercise Program were lower than those of the control group. 5. The scores for anxiety and depression in the experimental group that participated in the DanJeon Breathing Exercise Program were lower than those of the control group. In conclusion, DanJeon Breathing Exercise Program promotes the physical and emotional health of women in midlife. The DanJeon Breathing Exercise Program can be utilized as a nursing intervention for the promotion of health in women in midlife.

• Korean Journal of Optics and Photonics
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• v.23 no.6
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• pp.241-245
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• 2012

Measurements of the optical activity become very important issues in fields related to polymers, optical communications, astronomy, physics and many more. Hence it need to introduce this subject in our regular curriculum. In this experiment, an inexpensive, reliable, motorized polarimeter system which is suitable for undergraduate courses is constructed with PASCO's well-known Science Workshop 750 and a rotational motion sensor and light sensor, and the system is presented along with its experimental formulas. After responsivity of this system was checked by a half wave plate, and some repetitive experiments with 30% sucrose solution at 543.8 nm were performed. Comparing the experimental result with two calculated values from CRC data[1] showed that the specific rotation of the sucrose sample could be strongly suggested to be around +76 deg.cc/g.dm and it was an amply acceptable result for most undergraduate level courses.

• Journal of Korea Water Resources Association
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• v.44 no.2
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• pp.109-123
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• 2011

In this study, 2D finite volume model, which can apply to the mixed meshes that is effective to treat the complicated topography such as a natural river, is developed. To do so, an algorithm for finding the neighbouring cell of a computational cell is introduced, and fluxes are computed using the HLLC approximate Riemann solver at each interface between a computational cell and it's neighbouring cells. Moreover, in order to numerically treat the bed slope which has important effect on the balance between flux gradients and sourte terms, different formula to compute the bed slope for rectangular and triangular mesh are applied. The developed model is applied to analyze dam-break in an experimental channel with $90^{\circ}$ bend and Malpasset dam-break in France. The two cases consist of mixed meshes and the suggested method is validated for the experimental channel and natural channel by comparison with the experimental data, field data and computed results.

• Journal of Pharmacopuncture
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• v.19 no.2
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• pp.101-108
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• 2016

Objectives: This study introduces the history and types of Korean pharmacopuncture and reports trends of research on Korean pharmacopuncture. Methods: Pharmacopuncture studies were searched from the first year of each search engine to 2014 by using seven domestic and foreign search databases. Selected studies were divided into the history of pharmacopuncture, kinds and features of pharmacopuncture, research types, and experimental and clinic studies and were then classified by year of publication, type of pharmacopuncture, disease, and topic. Results: Pharmacopuncture can be classified into four large groups: meridian field pharmacopuncture (MFP), eight-principles pharmacopuncture (EPP), animal-based pharmacopuncture (ABP) and mountain-ginseng pharmacopuncture, which is a single-compound pharmacopuncture (SCP). The largest numbers of studies were reported from 1997 to 2006, after which the numbers decreased until 2014. Of experimental studies, 51.9%, 18.7%. 14.3%, 9% and 3.4% were on SCP, ABP, MFP, formula pharmacopuncture (FP), and EPP, respectively. Of clinical studies, 54.7%, 15.3%. 14.9% 10.0% and 1.5% were on ABP, MFP, EPP, SCP, and FP (1.5%), respectively. Among clinical studies, case reports and case series accounted for 76.5%, followed by randomized controlled trials (RCTs, 16.4%) and non-RCT (13.9%). Musculoskeletal diseases, toxicity and safety tests, anti-cancer effects, and nervous system diseases were mainly treated in experimental studies while musculoskeletal diseases, nervous system diseases, toxicity and safety tests, and autonomic nerve function tests were addressed in clinical studies. Bee venom (BV) was the most frequently-used pharmacopuncture in mechanism studies. Pharmacopuncture was mainly used to treat musculoskeletal diseases. Conclusion: Pharmacopuncture and studies of it have made great progress in Korea. Studies on BV pharmacopuncture and musculoskeletal diseases accounted for most of the studies reported during the review period. Research on the types of pharmacopuncture and diseases has to be expanded. Especially, studies on the use of MFP and EPP for treating patients with various diseases are needed.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.125-133
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• 2010

In general, curved bends raises a risk of overtopping due to floods and also threatens a bank safety due to a local flow concentration. This study aims to test the applicability of CCHE2D model for experimental flumes with two different types of bends and then investigate flow characteristics in the sharply-curved bend of a natural channel. The results demonstrated that the percent error of water level was within 4.9% for experimental flume applications and the simulated spatial distribution of velocity matched the observed results very closely. The calibrated model based on the experimental flumes was also applied to analyze the flow characteristics in natural channel bends of the Daeyu reach, located in a downstream of the Youngdam Dam. The results showed that in upstream, the simulated water level by the CCHED was observed at 1.5 m higher than the 1-D numerical model (HEC-RAS) result since the HEC-RAS could not represent the bend geometry effect on streamflow. However, the calculated results by several empirical formula support that the CCHE2D is suitable for the super elevation simulation as well as flood stage and velocity in a natural channel bend.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2B
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• pp.175-185
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• 2011

This study investigates tsunami force acting on a group of onshore structures numerically by using three-dimensional one-field model for immiscible multi-phase flows, which is based on Navier-Stokes solver. In particular, we studied on the characteristics of tsunami with respect to the arrangement of onshore structures and the distance from seawall trough numerical experiments. For validation of the numerical method used in this study to calculate tsunami force, numerical results for tsunami force on the structures in coastal area are compared with available experimental data. Furthermore, a detail study on the efficiency of the numerical method is performed for the estimation of tsunami force based on the hydrostatic and hydrodynamic methods in which the numerical results are used. The obtained results are compared to the previous experimental one and design criteria. Considering both experimental results and numerical analysis results, semi-empirical formula by regression analysis is proposed. As a result, it was confirmed that the numerical analysis is effective to estimate on tsunami force acting on onshore structures.

• Smart Structures and Systems
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• v.26 no.5
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• pp.605-617
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• 2020

In this study, the experimental tests for the direct tensile strength measurement of Ultra-High Performance Concrete (UHPC) were numerically modeled by using the discrete element method (circle type element) and Finite Element Method (FEM). The experimental tests used for the laboratory tensile strength measurement is the Compressive-to-Tensile Load Conversion (CTLC) device. In this paper, the failure process including the cracks initiation, propagation and coalescence studied and then the direct tensile strength of the UHPC specimens measured by the novel apparatus i.e., CTLC device. For this purpose, the UHPC member (each containing a central hole) prepared, and situated in the CTLC device which in turn placed in the universal testing machine. The direct tensile strength of the member is measured due to the direct tensile stress which is applied to this specimen by the CTLC device. This novel device transferring the applied compressive load to that of the tensile during the testing process. The UHPC beam specimen of size 150 × 60 × 190 mm and internal hole of 75 × 60 mm was used in this study. The rate of the applied compressive load to CTLC device through the universal testing machine was 0.02 MPa/s. The direct tensile strength of UHPC was found using a new formula based on the present analyses. The numerical simulation given in this study gives the tensile strength and failure behavior of the UHPC very close to those obtained experimentally by the CTLC device implemented in the universal testing machine. The percent variation between experimental results and numerical results was found as nearly 2%. PFC2D simulations of the direct tensile strength measuring specimen and ABAQUS simulation of the tested CTLC specimens both demonstrate the validity and capability of the proposed testing procedure for the direct tensile strength measurement of UHPC specimens.