• Journal of the Korean Wood Science and Technology
• /
• v.15 no.3
• /
• pp.44-55
• /
• 1987

In order to study the effect of sawdustboard combined with plastic chips, 0.5mm($T_1$), 1mm($T_2$), 1.4mm($T_3$) thick nylon fiber. polypropylene rope fiber(RP), and 0.23mm thick moth-proof polypropylene net fiber(NP) were cut into 0.5, 1, 2cm long plastic chips. Thereafter, sawdustboard combined with plastic chips prepared as the above and plastic non-combined sawdustboard(control) were manufactured into 3 types of one-, two-, and three layer with 5 or 10% combination level. By the discussions and results at this study, the significant conclusions of mechanical and physical properties were summarized as follows: 1. The MORs were shown in the order of 3 layer> 2 layer> 1 layer among plastic non-combined boards, and $T_3$ < $T_2$ < $T_1$ < RP (NP(5%) < NP(l0%) among plastic combined boards. In 2cm long plastic chip in 1 layer board, the highest strength through all the composition was recognized. 1 layer board showing the lower strength with 0.5cm plastic chip rendered to the bending strength improvement by 2 or 3 layer board composition. On the other hand, 2 or 3 layer combined with 1, 2cm long polypropylene net fiber chips incurred MOR's conspicuous decrease requiring optimum plastic chip combined level and consideration to combined type. 2. MOE in plastic non-combined 3 layer board exhibited sandwich construction effect by higher resin content application to surface layer in the order of 3layer>1layer>2layer with the highest stiffness of the board combined with polypropylene chip, while nylon chip-combined board had little difference from plastic non-combined board. In relevant to length and layer effect, 3 layer board combined with the 0.5cm long polypropylene net fiber chip in 5% and 10% combined level presented 34-43% and 44-76% stiffness increase against plastic non-combined board(control), respectively. Moreover, in 1 layer board, 30% stiffness increase with 10% against 5% combined level in the 1 and 2cm long polypropylene net fiber chip was obtained. 3. Stress at proportional limit(Spl) showing the fiber relationship (r: 0.81-0.97) between MOR presented in the order of 1 layer<2 layer<3 layer in plastic non-combined board. Correspondingly, combined effect by layer and plastic chip length was similar to MOR's. 4. Differently from previous properties(MOR, MOE, Spl). work to maximum load(Wml) of 2 layer board approached to that of 3 layer board. Conforming the above phenomenon. 2 layer combined with 0.5cm long polypropylene net fiber chip kept the greater work than 1 layer. The polypropylene combined board superior to nylon -and plastic non - combined board seemed to have greater anti - failing capacity. 5. Internal bond strength(IB), in contrast to MOR's tendency. showed in the order of T1

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.23 no.10
• /
• pp.869-877
• /
• 2013

Tension force of hanger ropes has been recognized and utilized as an important parameter for health monitoring of suspension bridges. Conventional vibration method based on string theory has been utilized to estimate tension forces of relatively long hanger ropes without any problem, however it is convinced that the vibration method is not applicable for shorter hanger ropes in which the influence of flexural stiffness is not ignorable. Therefore, as an alternative of vibration method, a number of feasibility studies of system identification(SI) technique considering flexural stiffness of the hanger ropes are recently performed. In this study, the influence of support condition of the finite element model utilized for the SI method is investigated with numerical examples. The numerical examples are prepared with the specification of the Kwang-Ahn bridge hanger ropes, and it is revealed that the estimation result of the tension force can be varied from -21.6 % to +35.3 % of the exact value according to the consideration of the support condition of FE model. Therefore, it is concluded that the rotational stiffness of the support spring should be included to the list of the identification parameters of the FE model to improve the result of tension estimation.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.51 no.1
• /
• pp.26-34
• /
• 2015

The angle of attack of a cambered otter board in a bottom trawl was estimated using a three-dimensional semi-analytic treatment of a towing cable (warp) system that was applied to the field experiments of a bottom trawl obtained by the Scanmar system. The equilibrium condition of the horizontal component and vertical component of forces was used to the three forces acting on the otter board in the horizontal plane. Those forces were the force on the warp at the bracket, hydrodynamic lift and drag forces on the otter board and the force on the hand rope attached just behind the otter board. Also the equilibrium of moment about the front edge of the otter board was used to find out the angle of attack of the cambered otter board. When the warp length was 120m and 180m long and the towing speed was between 1.23 and 1.90 m/s, the estimated angle of attack of the cambered otter board was ranged between $26.1^{\circ}$ and $29.6^{\circ}$, respectively, though the maximum lift force was at the angle of attack $22.6^{\circ}$. The angle of attack of the otter board was tended to increase weakly with the longer length of warp (180 m) at the same towing speed in the experiment.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.12
• /
• pp.8437-8446
• /
• 2015

This study was designed to examine the effects of weight reduction programme(WRP) for obese primary school students on serum lipid level. This research used non-equivalent control group non-synchronized design that was conducted on two groups comprising 5th and 6th graders: an experimental group that received 12-week long WRP that combines diet, exercise and behavior modification therapy and the control group that did only rope-jumping. The collected data were analysed using ${\chi}^2$-test, t-test, ANOVA, Pairwise Comparsons by SPSS 18.0 Programme. It was proven that the WRP of this study was effective in lowering the total cholesterol(F=4.21, p=.049) and triglyceride(F=4.25, p=.049). WRP may be used as a basis for further studies that may be conducted after intervening the motivation level of the study subjects.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1991.10a
• /
• pp.111-114
• /
• 1991

The KMRR 4-wheel crane which has a span of 30.6m long shall be designed to maintain its structural integrity during and after seismic shocks. Horizontal and vertical FRS for OBE and SSE conditions at the crane support are after seismic shock. Horizontal and vertical FRS for analysis are 4% for OBE and 7% for SSE. The crane consists of girder, saddle main and auxiliary trolley, and necessaries. They are modeled as beam elements and lumped masses for the following 4 cases ; trolley at center of the crane with and without the rated load, trolley at end with and without the rated load. The static analysis as well as the linear dynamic analysis including frequency and response spectrum analysis are performed for the seismic qualification of the crane using the Finite Element Method. For the simplicity of the analysis, the decoupling criteria are considered for the crane rope and the crane supporting beams. The main sections of the crane are stiffened until the calculated stresses satisfy the allowable limits. The seismic resultant loads are used to design the seismic restraints of the saddle and the trolley to protect the clue from the seismic uplifting loads the study results have show that the seismic design of the KMRR crane is governed by the OBE condition. not by the SSE condition. This paper briefly describes the analysis procedure used in the seismic design of the KMRR crane, and summarizes the analysis results.

• Journal of the Korean Society of Physical Medicine
• /
• v.8 no.4
• /
• pp.627-635
• /
• 2013

PURPOSE: The purpose of this study is to identify how the body composition changes after jump-roping exercise. METHODS: The subjects are 40 college students, 20 females and 20 males. The subjects were selected among college students who had not taken any drug for more than 4 weeks before the experiment started. The experiment was performed for 4 weeks, from May 23rd to June 13rd, 2012. To collect the data, the vital signs such as pulse, blood pressure, weight), and the body composition were measured before and after the experiment. The data on the body composition were analyzed by the electrical resistance analyzer. RESULT: Muscle mass was increased and body fat was decreased for both females and males after the exercise. In particular the increase of the muscle mass and the decrease of the body fat for the females were statistically significant. The result that the body fat of the females was decreased significantly more than that of males is interpreted that the body fat of females are comparatively higher than that of males. Additionally the muscle mass of the left arm and leg of the subjects were significantly increased(p<.05). Correlation analysis between general characteristics such as body composition, abdominal obesity and specific muscle areas for both men and women showed generally positive between before and after the jump-roping exercise (p<.05, p<.01). However the correlation between sleeping time and each variable showed negative. CONCLUSION: A according to the result of this study, jump-roping exercise had a very positive effect on the body composition. The study suggests that college students keep jump roping for a long period to change their body composition favorably.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.28 no.1
• /
• pp.35-48
• /
• 1995

To develop the optimal design method for the longline type scallop culturing facilities in the open sea numerical calculations and hydraulic model experiments are carried out for the stability and function optimization. Using the results for the motion and tension of the facilities, stable design concepts and effects of motion control system by vertical anchor and resistance discs art discussed. The results of this study that can be applied to the design are as follows: 1) Total external forces by design wave $(H_{1/3}\;=\;6,7\;m,\;T_{1/3}\;=\;12sec)$ at the coastal waters of Jumunjin for unit facility (one main line) are estimated to 5-20 tons, and required anchor weights are 10-40 tons in the case of 2-point mooring system. Though the present facilities are stable to steady currents, but is unstable to the extreme wave condition of return period of 10 years. 2) The dimensions and depth of array systems must be designed considering the ecological environments as well as the physical characteristics including the mooring and holding forces that are proportional to the length and relative depth of main line to wave length, and the number of buoys and nets. 3) Oscillation of the facility is influenced by water particle motion and the weight of hanging net, and is excited at both edge, especially at the lee side. To reduce the motion of the nets, the vertical anchoring system and the resistence disc method are recommended by the experimental results, 4) The damage of rope near the anchor by abrasion should be prevented using the ring-type connection parts or anchor chains.

• ALGAE
• /
• v.33 no.1
• /
• pp.101-108
• /
• 2018

Saccharina japonica was introduced to both Korea and China from Hokkaido, Japan, and it has become an economically important species in both nations. After a long period of cultivation, several varieties of S. japonica have been developed in Korea and China. In this study, we conducted aquacultural research on the persistence of thalli from two kelp cultivars, one from China (Huangguan No. 1) and one from Korea (Sugwawon No. 301), between December 2015 and November 2016 in Haenam, Korea. The maximum length was $247.8{\pm}13.0$ and $227.5{\pm}42.0cm$, respectively, which were significantly longer in Sugwawon No. 301 than in Huangguan No. 1. The maximum width was $29.9{\pm}5.4$ and $23.2{\pm}1.9cm$, respectively, which were significantly wider in Huangguan No. 1 than in Sugwawon No. 301. The mean biomass obtained from the culture ropes was for Sugwawon No. 301 was $3.5{\pm}0.3kg\;wet\;wt\;m^{-1}$ and for while Huangguan No. 1 was $3.1{\pm}1.0kg\;wet\;wt\;m^{-1}$ of culture rope. After August, the persistence of the thalli of Sugwawon No. 301 was two months longer than that of Huangguan No. 1. We found that the Sugwawon No. 301 performed as well as the Huangguan No. 1 in Korean waters possibly due to increased flexibility as a result of the different cell arrangements of the two cultivars. Overall, the use of the Sugwawon No. 301 cultivar rather than the Huangguan No. 1 cultivar of S. japonica appears the best alternative to help to ensure a stable year round algal feed supply for the Korean abalone industry.

• Journal of Navigation and Port Research
• /
• v.29 no.8 s.104
• /
• pp.661-666
• /
• 2005

Recent warnings indicate that there is a potential risk of massive earthquake. These earthquakes could produce large-scale tsunamis. Consideration of the effect of Tsunami to the moored ship is very important bemuse it brings the loss of life and vast property damage in a viewpoint of ship operations within a harbor. If a tsunami occurs, a ship in a harbor may begin drifting in case of ship entering and departing harbor, and breakage of mooring rope and drifting of moored ship are happened. And extremely serious accident, such as stranding and collision to a quay, might occur. On the other hand, since the tsunami consists of approximately component waves of several minutes, there is a possibility of resonance with the long period motion of mooring vessel. As the speed of Tsunami is much faster than tidal current in a harbor, a strong resisting force might act on the moored ships. In this paper, the numerical simulation procedure in the matter of ship motions due to the attack of large-scale tsunamis are investigated and the effects on the ship motions and mooring loads are evaluated by numerical simulation.

• Journal of the Korean Society of Costume
• /
• v.67 no.4
• /
• pp.1-20
• /
• 2017

Centered on Kathleen Kye, a designer who conveyed messages on social issues through her dresses, and established her own identity, this study aimed to examine what theme, method of expression and inner meaning her 'statement' had, as a way of expressing a critical awareness. After reviewing discussions by Duggan G. G. as well as dictionary definitions, statement fashion design can be defined as a work or fashion shows containing a message of a designer who is free from a particular trend or consumerism in various social issues. Statement fashion designers give opposing messages on social issues through their fashion collections. As a result, research shows that contemporary statement fashion designers are expressing themes of a fashion systems, fetishism, body image, collision, environment, as well as the socially disadvantaged by appropriation, reuse, slogan, metaphorical pattern and performance. Satire, awakening, challenge and support can be derived from the inner meaning of contemporary statement fashion design. In terms of the theme, method of expression and inner meaning, this study showed that KYE collection of the designer Kathleen Kye expresses critical awareness on the modern society. Research findings reveal that KYE collection include the following themes: long-term youth unemployment, conflict collision in war or on the Internet, fetishism by youth in a get-rich-quick fever, environmental issue causing destruction of an ecosystem by decrease in bee population, school violence and the socially disadvantaged related to alienated immigrants. Also, as a method of expression themes, such as metaphorical patterns, were used. The patterns used images including a skeleton, gun, heart, rope, plaster, homeless box, bee, honeycomb, chain and a slot machine. On the other hand, the inner meaning of statement in KYE collection showed satire on social issues, awakening on social issues unrecognized by the masses, and support for the socially disadvantaged.