• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.74-81
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• 2004

In this study preliminary structural design has been performed to develop an all composite wing box for experimental aircraft(classified in FAR Part 21). Considerations on composite materials and their manufacturing process were taken into account throughout the design phase. Aerodynamic loads were estimated by using Shrenk method(NACA TM No 948) and FAR Part 23 Appendix A. The structural layout has been determined to carry effectively the critical loads and to maximize the benefit of composite structure. Maximum strain failure allowable and first ply failure criteria were applied for the sizing of major structural members. Finally, the designed composite wing box structure is presented in the form of drawings, which include material specifications, stacking sequences and joint design.

• Sim-seong Yeon-gu
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• v.39 no.1
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• pp.129-183
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• 2024

This study is an attempt to get closer to the psychological truth of alcohol addiction. After reviewing previous related studies, the experiences of Korean alcoholics were examined, encompassing both the conscious and unconscious aspects. In order to approach the unconscious, the researcher paid attention to the series of dreams that the patients reported, from the perspective of Jungian dream analysis. Working with dreams brought considerable benefits in increasing patient's involvement in the therapeutic process and fostering therapist-patient alliance. It also helped to understand patients' conscious and unconscious aspects further. The results were as follows. On the conscious level, patients showed a long-standing alienation from their true emotional needs, a lack of sufficient experience in genuinely expressing and being accepted with one's own emotion, resulting in the need for emotional re-experience, along with the intense longing for maternal affection. This also meant that they were in need for maternal re-experience, and at the same time, for the associated paternal re-experience. Furthermore, the researcher identified that certain powerful archetypal complexes had been activated in the patient's unconscious in response to their conscious situations, triggering the destructive shadows to emerge and exert a strong influence on their conscious lives. The series of reported dreams shows how the unconscious always properly and diligently compensates, modifying the perspective and attitude of the conscious and gradually opening the doors to healing, even for alcoholic patients. This indicates that the unconscious carries out a specific and consistent guidance role so the conscious can realize and adequately respond to it, and that it also provides the creative force for transforming the conscious life. These findings suggest that alcohol addiction is a psychological condition that can jeopardize one's life by allowing the powerful energy of the unconscious to penetrate the conscious, but at the same time, have the purpose and direction to urge the creative transformation of one's conscious life. From these results, it can be concluded that the first step towards true recovery is for the individual to turn their attention towards the psychological truth occurring within themselves. In this regard, the therapist's role is crucial. This also suggests that various attempts in the field of addiction treatment will blossom their real values when they contribute, directly or indirectly, to the development of one's self-awareness since as long as one continues to turn away from the psychological truth and persist in craving for false objects, their creative healing properties in the unconscious could rather have negative and destructive impacts on their life.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.8-14
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• 2019

A drop structure, one of the representative river-crossing structures, is constructed to stabilize a riverbed. On the other hand, the structure interrupts the continuity of the river and causes the destruction of the hydro-ecological environment. Therefore, laboratory experiments of a natural type of drop structure with low differences were performed, and the empirical formula of a local scour hole is proposed. Four experimental flow rates were tested for various types of the drop structure models with 28 test cases. Based on the scour test, it was confirmed that the maximum scour depth occurs rather than the result of applying the previously proposed scour depth formulae. Correlation analysis of the major factors of scour hole at the downstream of the drop structure revealed a strong correlation between the upstream flow characteristics, drop structure height, and total crossing length of the drop model. In addition, the depth and length estimation formula of the maximum scour hole were proposed using the dimensionless variables and validated. In the future, it is also expected that more accurate scour prediction and calculation can be derived by conducting experimental studies and numerical analysis considering the various bed materials and flow conditions.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.2
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• pp.154-162
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• 2011

A reliability analysis model is developed for evaluating the crest freeboard of vertical breakwaters based on the concepts of maximum overtopping volume of individual wave. A reliability function is formulated by defining the margin of admissible overtopping volume and maximum overtopping volume that is depend on the number of overtopping waves, dimensionless crest freeboard, and mean overtopping discharge. In addition, Level III MCS technique is straightforwardly suggested by which the related empirical parameters to reliability function can be considered to be random variables with the wide range of different uncertainties. It can be possible to calculate the probabilities of failure according to the relative crest freeboard with the variations of the incident wave directions, the structural types of vertical breakwaters, and admissible overtopping volumes in conditions of the long and short crested-waves.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.113-113
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• 2017

중소하천에서 홍수 시 보 주변 흐름은 잠수월류(submerged overflow)의 형태이고, 이러한 조건 하의 보 파괴원인 중 가장 큰 부분은 제방과의 연결부에서 발생하는 세굴로 인한 것이다. 그러나 하천설계기준(2009)에서는 보 연결부 보호공에 대해 수리학적 특성과 유사적 특성을 고려한 적절한 세굴 범위를 제시하지 못하고 있는 실정이다. 또한 기존의 연구들은 주로 고정상 실험결과를 이용하여 세굴범위를 제시하고 있으며, 제체의 재료적 특성을 고려한 연구가 상대적으로 미약한 실정이다. 이에 본 연구에서는 제체의 재료적 특성(점성을 가진 유사 특성)을 고려하여 잠수월류 시 보 하류부 제방의 세굴길이를 도출하였다. 본 연구방법으로 이론적 접근에서 보 연결부 세굴을 유발하는 주요인자들을 활용하여 관계식을 제안하였고, 수리실험을 통해 제안된 식의 검증을 수행하였다. 수리실험은 균일 사다리꼴 단면의 직선 수로($7.0m(L){\times}2.0m(B){\times}0.5m(H)$)에서 이동상 제방구간(2.0m)과 고정상 제방구간을 나누어 실험의 효율성을 높이고자 하였으며, 이동상 제방 전용 다짐판 및 다짐 봉 등 자체적으로 제작된 실험 장비들이 이용되었다. 실험결과와 제시된 이론적 접근의 비교를 통해 제시된 이론식이 제체의 다짐도의 영향이 고려가 되지 않았음을 가정하였으며, Lee et al.(2001)의 연구를 참고하여 제체에 대한 다짐의 영향을 고려한 후 두 값들이 선형적인 비례 관계가 나타남을 확인하였다. 최종적으로 이러한 관계를 모두 고려한 잠수월류 시 보 하류부 세굴길이에 대한 예측식을 제안하였다. 본 예측식은 하천 계획 및 설계시 호안의 범위를 산정하는데 참고자료로 유용할 것으로 판단된다. 향후에는 완전월류(perfect overflow)에서 보 연결부 세굴에 대한 연구를 수행하여, 월류 형태 별 제방 세굴길이에 대한 연구를 완성하고자 한다.

• Journal of the Korea Concrete Institute
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• v.18 no.2 s.92
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• pp.161-168
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• 2006

An experimental investigation was conducted to examine the hysteretic behaviors of ultra-high strength concrete tied columns. The purpose of this study is to investigate the safety of ultra-high strength concrete columns with 100 MPa compressive strength for the requirement of ACI provisions. Eight 1/3 scaled columns were fabricated to simulate an 1/2 story of actual structural members with the cross section $300{\times}300mm$ and the aspect ratio 4. The main variables are axial load ratio, configurations and volumetric ratios of transverse reinforcement. The results show that the deformability of columns are affected by the configurations and volumetric ratios of transverse reinforcement. Especially, it has been found that the behavior of columns are affected by axial load ratio rather than the amounts and the configurations of transverse reinforcement. Consequently, to secure the ductile behavior of 100 MPa ultra-high strength concrete columns, ACI provisions for the requirement of transverse steel may considered axial load level and the details of transverse reinforcement.

• The Journal of Engineering Geology
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• v.11 no.1
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• pp.1-11
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• 2001

The geological characteristics of Korea are that we can encounter the rock layer only after 10m of excavation, methods to presume the rock pressure distribution of the rock layer is urgently needed. When using the existing empiric science of Terzaghi-Peck, Tschebotarioff to measure the rock pressure of the rock layer, underestimate the real strength because of the cohesion is ignored. Therefore calculating the horizontal sliding force of wedge block, which includes the dips and shear strength of discontinuities and surcharge load etc., think to be to getting a closer rock stress of the real rock pressure acting upon the earth structure in rock mass. This research use Coulomb soil pressure theory assuming that the backfill soil will yield wedge failure when it has cohesion, applying Prakash-Saran(l963), and then it uses equilibrium of force and shear strength $\tau$=c+$\sigma$tan $\Phi$ of the cliscontinuities. Analyzing shear strength and dips of cliscontinuities using calculated theory according to the status of discontinuities aperture, we were able to find out that because the cohesion and friction angle of the rock layer itself is large enough, how the dip directions and dips facing the excavation face is the only factor deciding whether or not the rock stress is applied. The evaluated theory of this research should be strictly estimated, so that the many parameters such as c, $\Phi$value, types and structures of rock class, excessive lateral pressure, dynamic load, earthquake, needed later when calculating shear strength of discontinuities and especially the ground water effect acting on rock layer should be coumpted with many measuring data achieve at the insite to study the application.

• Journal of the Korean GEO-environmental Society
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• v.16 no.3
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• pp.5-13
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• 2015

Wave overflow can cause a failure of sea dike structure. Based on the results of the field surveys on mound-type sea dike, the failure of vicinity of crown and the scouring of toe at the landward was revealed as the most representative failure example. One of the main factors related to this failure pattern is overflow-induced pressure and velocity. Thus, in this study the analytical equations which can determine the pressure and the velocity induced by overflow in sea dike were proposed and verified. To accomplish this, assumed that the flow is quasi-steady and irrotational, and concentric circular streamlines around the vicinity of crown and toe of the sea dike. Flow was assumed as critical state and Bernoulli equation was used to develop the equations that can determine the pressure and velocity at the vicinity of crown and toe of the sea dike. Using these equations, the pressure and the velocity were calculated in condition of various overflow depths and radiuses of circular streamline. Based on the calculation results, while a negative pressure was occurred at the vicinity of crown, a significant amount of positive pressure occurred at the toe. The existence of flow-induced shear stresses was also confirmed. In addition, the limitation of the proposed equations was discussed.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.237-244
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• 1996

Propanil [N-(3,4-dichlorophenyl) propanamide] which was applied at 4,200g ai/hapostemergence 7 days after seeding or transplanting, completely reduced the growth of shoot and root of barnyardgrass at 100% under dry condition while plant height, root length and shoot fresh weight of barnyardgrass at 63, 40 and 78%, respectively under water condition. On the other hand, the herbicide did not affect the growth of shoot and root of rice grown under water condition and transplanting condition, but reduced the plant height, root length and shoot fresh weight of broadcast rice on soil at 24, 18 and 28%, respectively, under dry condition. Microscopically, the epidermal cells of treated-barnyardgrasses under both conditions were severely constricted, chloroplasts in the cells of vascular bunble sheath were partially lacked, and mesophyll cells were often ruptured, whereas those of treated-rice were not affected. Histological observations showed that propanil reduced the thickness of leaf blade of barnyardgrass under both conditions at 36-48% due to mainly reduction and constriction of mesophyll cell, while it did not affect or even increased the thickness of leaves of rice under all conditions compared to control. These results indicate that broadcast rice on soil were more injured than drilled rice in soil under dry condition, however, in the other tested conditions ricer were not affected.

• Journal of the Korea Concrete Institute
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• v.21 no.6
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• pp.719-727
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• 2009

The requirements of the maximum shear reinforcement in the EC2-02 and CSA-04, which are developed based on the truss model, are quite different to those in the ACI-08 code and AIJ-99 code, which are empirical equations. The ACI 318-08, CSA-04, and EC2-02 codes provide an expression for the maximum amount of shear reinforcement ratio as a function of the concrete compressive strength, but Japanese code does not take the influence of the concrete compressive strength into account. For high strength concrete, the maximum amount of shear reinforcement calculated by the EC2-02 and CSA-04 is much greater than that calculated by the ACI 318-08. Ten RC beams having various shear reinforcement ratios were tested and their corresponding shear stress-shear strain curves and failure modes were compared to the predicted ones obtained by the current design codes.