• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.481-495
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• 2020

After the resonator on the basis of the wave-filter theory was designed to control the waves with a specific frequency range surging into the harbor, the several case with the use of resonator have been reported in some part of sea, including the port of Long Beach, USA, and yacht harbor at Rome, Italy in order to control the long-period wave motion from the vessels. Recently, the utility and applicability of the resonator has been sufficiently verified in respect of the control of tsunami approximated as the solitary wave and/or the super long-period waves. However, the case with the application of tsunami in the real sea have not been reported yet. In this research, the respective case with the use of existing resonator at the port of Mukho and Imwon located in the eastern coast of South Korea were studied by using the numerical analysis through the COMCOT model adapting the reduction rate of 1983 Central East Sea tsunami and 1993 Hokkaido Southwest off tsunami. Consequently, the effectiveness of resonator against tsunami in the real sea was confirmed through the reduction rate of maximum 40~50% at the port of Mukho, and maximum 21% at the port of Imwom, respectively. In addition, it was concluded that it is necessary to study about the various case with application of different shape, arrangement, and size of resonator in order to design the optimal resonator considering the site condition.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.3-9
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• 2014

Purpose: Our goals were to evaluate the effect of high dose radioiodine treatment for thyroid cancer by taking in laxatives. Materials and Methods: Twenty patients(M:F=13:7, age $46.3{\pm}8.1\;yrs$) who underwent high dose radioiodine treatment were seperated into Group 1 taking $^{131}I$ 5,500 MBq and Group 2 with the use of laxatives after taking $^{131}I$ 5,500 MBq. The whole body was scanned 16 hours and 40 hours after taking radioactive iodines by using gamma camera, the ROIs were drawn on the gastro-intestinal tract and thigh for calculation of reduction ratio. At particular time during hospitalization, the radioactivity remaining in the body was measured in 1 meter from patient by using survey meter (RadEye-G10, Thermo Fisher Scientific, USA). Schematic presentation of an Origin 8.5.1 software was used for spatial dose rate. Statistical comparison between groups were done using independent samples t-test. P value less than 0.05 was regarded as statistically significant. Results: The reduction ratio in gastro-intestinal 16 hours and 40 hours after taking laxatives is $42.1{\pm}6.3%$ in Group 1 and $72.1{\pm}6.4%$ in Group 2. The spatial dose rate measured when discharging from hospital was $23.8{\pm}6.7{\mu}Sv/h$ in Group 1 and $8.2{\pm}2.4{\mu}Sv/h$ in Group 2. The radioactivity remaining in the body is much decreased at the patient with laxatives(P<0.05). Conclusion: The use in combination with laxatives is helpful for decreasing radioactivity remaining in the body. The radioactive contamination could be decreased at marginal individuals from patients.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.1
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• pp.1-12
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• 1995

Isothermal and thermal-mechanical fatigue characteristics of 12Cr heat resisting steel used for high temperature applications were investigated including hold time effects. Isothermal low cycle fatigue test at $600^{\circ}C$ and in-phase, out-of-phase thermal-mechanical fatigue test at 350 to $600^{\circ}C$ were conducted using smooth cylindrical hollow specimen under strain-control with total strain ranges from 0.006 to 0.015. Regardless of thermal-mechanical and isothermal fatigue tests, cyclic softening behavior was observed and much more pronounced in the thermal-mechanical fatigue tests with hold times due to the stress relaxation during the hold time. The phase difference between temperature and strain in thermal-mechanical fatigue tests resulted in significantly shorter fatigue life for out-of-phase compared to in-phase. The differences in fatigue lives were dependent upon the magnitudes of plastic strain ranges and mean stresses. During the hold time in the strain-controlled fatigue tests, the increase in the plastic strain range and the stress relaxation were observed. It appeared that the increase in plastic strain range per cycle and the introduction of creep damage made important contributions to the reduction of thermal-mechanical fatigue life with hold time, and the life reduction tendency was more remarkable in the in-phase than in the out-of-phase thermal-mechanical fatigue. Isothermal fatigue tests performed under the combination of fast and slow strain rates at $600^{\circ}C$ showed that the fatigue life decreased as the strain rate and frequency decreased,especially for the low strain ranges.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.3
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• pp.295-302
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• 2014

An internal gear pump is required to improve the flow rate and noise. Furthermore, such pumps are durable and small in size. In this study, equations of the rotor shape with multiple profiles (ellipse 1-involute-ellipse 2) were derived, and relevant performance parameters (pressure angle, irregularity, and specific sliding) of the internal gear pump to noise were predicted and compared. Rotor profiles and performance parameters were obtained by a prediction algorithm for theoretical analysis, and the effects between the design parameters and the performance parameters were analyzed. Based on the analysis results of the effects, an optimal design of the rotor profile was proposed, and a noise test of the prototype was performed to evaluate the reliability of the design.

• Steel and Composite Structures
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• v.22 no.1
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• pp.141-159
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• 2016

Commonly in steel frames, steel beam and concrete slab are connected together by shear keys to work as a unit member which is called composite beam. When a composite beam is subjected to positive bending, flexural strength and stiffness of the beam can be increased due to "composite action". At the same time despite these advantages, composite action increases the strain at the beam bottom flange and it might affect beam plastic rotation capacity. This paper presents results of study on the rotation capacity of composite beam connected to Rectangular Hollow Section (RHS) column in the steel moment resisting frame buildings. Due to out-of-plane deformation of column flange, moment transfer efficiency of web connection is reduced and this results in reduction of beam plastic rotation capacity. In order to investigate the effects of width-to-thickness ratio (B/t) of RHS column on the rotation capacity of composite beam, cyclic loading tests were conducted on three full scale beam-to-column subassemblies. Detailed study on the different steel beam damages and concrete slab damages are presented. Experimental data showed the importance of this parameter of RHS column on the seismic behavior of composite beams. It is found that occurrence of severe concrete bearing crush at the face of RHS column of specimen with smaller width-to-thickness ratio resulted in considerable reduction on the rate of strain increase in the bottom flange. This behavior resulted in considerable improvement of rotation capacity of this specimen compared with composite and even bare steel beam connected to the RHS column with larger width-to-thickness ratio.

• Economic and Environmental Geology
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• v.35 no.5
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• pp.421-428
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• 2002

Lab-scale experiments were conducted to evaluate the effect of surface tension reduction on the extension of the influence zone and the VOC removal efficiency of ground water sparging. A glass column packed with coarse sand was used for VOC removal test at two different surface tensions. A glass column without porous media was also used fer control purpose prior to sand-packed column test. A quasi-two-dimensional glass box model, packed with a sand, was used fer sparging zone tests at different water surface tensions. Surface tension of the aquoues solution used in this study was controlled using sodium dodecyl sulfate (SDS). For the glass, sand column experiments, total amount of air filled in the media increased as surface tension decreased. Toluene (used as VOC in this study) removal rate increased slightly with decreased surface tension f3r both free water column and sand-packed column. Air sparging zone extended up to 500% as the surface tension decreased. Combining the results from two different experiments, VOC removal efficiency is expected to increase significantly with surface tension reduction.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.368-372
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• 2007

Recently, construction companies prefer to use large scale system forms to prepare for lacking of skilled workers, aging and the chances of application of pre-build&post-sale policy. In result of the effort and interest, the duration for framework of domestic high rise buildings has been accomplished to 3-4days per floor but for the apartment housing which form over 90% of the domestic construction industry, and especially the middle story RC apartments which is the main part, the duration for framework is only about 6-8days per level. This is only about 50% of the duration per level of RC residential buildings in North America. In previous researches elementary technology, which has potential of duration reduction, was proposed and this research suggest the applicability in construction sites and ways to improve it using elementary technology applied Mock-up Test. Furthermore, we analyze the productivity and T/C usage rate of the 6day-Cycle and suggest an improved model.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.2
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• pp.143-150
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• 2010

Vitrification technology has been gradually recognized as one of effective solidification methods for concentrated boric acid wastes generated in PWR. Vitrification for low- and intermediate-level radioactive wastes has a large volume reduction and good durability for the final products. A feasibility study for the vitrification of concentrated boric acid wastes has been performed with developing the pre-treatment methods of powdered wastes, glass compositions using glass formulation and demonstration test. The pre-treatment method is pelletizing the powder type for stable feeding within cold crucible melter. The glass compositions should be developed considering molten glass are related with wastes reduction. High contents of sodium and boron within borate wastes give influence to waste loading. A variety of factors obtained from the demonstration test are reviewed, which is wastes feeding rate, off-gas characteristics on stack and glass characteristics of final products such as durability for implementing the wastes disposal requirement. The aim of this paper is to present the feasibility of vitrification and review the solidification method for concentrated boric acid wastes and obtain the physicochemical characteristics of solidified glass.

• Journal of Korean Medicine for Obesity Research
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• v.3 no.1
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• pp.25-35
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• 2003

Objectives : This study was aimed to investigate the change of the reduction in body weight and the change of body composition after fasting therapy, Chulsikyopub, which was put into practice in Dept. of oriental rehabilitation medicine at Kyung Hee oriental hospital. Method : We measured body weight, body composition, and the degree of obesity 2 weeks after fasting therapy and 10 weeks after fasting therapy with body composition analyzer(Inbody 2.0). Statistical comparisons between pre-therapy group and post-therpay group were done by paired t-test and Wilcoxon's signed rank test. Results : 2 weeks after fasting therapy, body weight was decreased 7.33kg(9.18%), body fat was decreased 2.47Kg(7.24%), muscle weight was decreased 4.66kg(11.37%), body fat ratio was increased 1.08%, and body metabolic rate(BMR) was decreased 118.23kcal(8.22%). 10 weeks after fasting therapy, each of body weight and fat was decreased 10.4Kg, muscle weight was increased 0.3Kg(0.7%), body fat ratio was decreased 7.9%, and BMR was increased 6.8Kcal(0.47%). But muscle weight and BMR did not satisfy statistical significance. Conclusions : fasting therapy for 10 weeks reduced body weight and body fat statistically significant without loss of muscle weight and BMR.

• Journal of Energy Engineering
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• v.28 no.2
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• pp.47-54
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• 2019

As absorption type heat pump for waste heat recovery is installed in combined cycle power plant for Energy Service Company, performance test is implemented to confirm the operation data on partial load. The operation data changes according to the heat pump operation on partial load are as follows. Total heat output increases, because waste heat of closed cooling water and a portion of LP steam from HRSG is supplied. But electric power output of steam turbine is reduced, because LP steam to steam turbine is reduced. And heat output from HP district heater and LP district heater is reduced, because HP turbine exhaust steam to HP district heater and LP district heater is reduced. On partial load operation, turbine output reduction is higher than the base load operation. Therefore, on partial load, heat pump should be operated in consideration of the heat output increase and electric power output reduction.