• Journal of Korean Association for Spatial Structures
• /
• v.11 no.2
• /
• pp.71-79
• /
• 2011

Due to the self-equilibrium status of the cable system, the loss of the tensioning in the cable system results in other cables carrying larger tension forces than those initially calculated by structural engineers. Also, turn-buckle systems, which have been widely used to pre-tension and/or re-tension the cables, are limited to use for small cables and to provide a rough estimation for tension forces. In this study, the re-tensioning cable connection systems were developed to overcome the problems mentioned above. The main objective of the proposed system is to re-tension large cables and measure the exact amount of tension forces of the cable systems. This connection system is also combined with the wireless signal monitoring module so that engineers are able to measure the tension forces any place where the internet is available. This paper presents the development of the re-tensioning cable connection systems and experiment using the real-scale cable systems to verify the fe-tensioning and signal monitoring systems.

• Journal of the Korean Chemical Society
• /
• v.45 no.5
• /
• pp.401-412
• /
• 2001

The geometrical parameters, vibrational frequencies, and dissociation energies for $H_{2n+1}^+$ (n=1~6) clusters have been investigated using high level ab initio quantum mechanical techniques with large basis sets. The equilibrium geometries have been optimized at the self-consistent field (SCF), the single and double excitation configuration interaction (CISD), the coupled cluster with single and double excitation (CCSD), and the CCSD with connected triple excitations [CCSD(T)] levels of theory. The highest levels of theory employed in this study are TZ2P+d CCSD(T) up to $H^+_g$ and TZ2P CCSD(T) for $H_{11}^+$ and $H_{13}^+$. Harmonic vibrational frequencies are also determined at the SCF level of theory with various basis sets and confirm that all the optimized geometries are true minima. The dissociation energies, $D_e$, for $H_{2n+1}^+$ (n=26) have been predicted using energy differences at each optimized geometry and zero-point vibrational energies(ZPVEs) have been considered to compare with experimental dissociation energies, $D_0$.

• Journal of the Korean GEO-environmental Society
• /
• v.15 no.3
• /
• pp.41-48
• /
• 2014

Experimental study of sedimentation and self-weight consolidation has been primary research area in dredged soil. However, good quality of the dredged soil and minimum water pollution caused by the pumping of reclaimed soil require intensive study of the flow characteristics of dredged material due to dumping. In this study, continuity and the equilibrium equations for mass flow assuming single phase was derived to simulate mass flow in dredged containment area. To optimize computation and modeling time for three dimensional geometry and boundary conditions, depth integration is applied to governing equations to consider three dimensional topography of the site. Petrov-Galerkin formulation is applied in spatial discretization of governing equations. Generalized trapezoidal rule is used for time integration, and Newton iteration process approximated the solution. DG and CDG technique were used for weighting matrix in discontinuous test function in dredged flow analysis, and numerical stability was evaluated by performed a square slump simulation. A comparative analysis for numerical methods showed that DG method applied to SU / PG formulation gives minimal pseudo oscillation and reliable numerical results.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.13 no.4
• /
• pp.417-425
• /
• 2000

This paper describes the application of discretized continuum-type optimality criteria(DCOC) and the development of optimum design program for the reinforced concrete continuous beams with rectangular cross-section. The cost of construction as objective function which includes the costs of concrete, reinforcing steel and formwork is minimized. The design constraints include limits on the maximum deflection, flexural and shear strengths, in addition to ductility requirements, and upper and lower bounds on design variables as stipulated by the design Code. Based on Kuhn-Tucker necessary conditions, the optimality criteria are explicitly derived in terms of the design variables-effective depth, and steel ratio. The self-weight of the beam is included in the equilibrium equation of the real system. An iterative procedure and computer program for updating the design variables are developed. Two numerical examples of reinforced concrete continuous beams are presented to show the applicability and efficiency of the DCOC-based technique.

• Journal of Sasang Constitutional Medicine
• /
• v.21 no.2
• /
• pp.11-26
• /
• 2009

1. Objectives : This research was purposed to reconsider the Dong-Mu's Theory of Nature and Mind(生情論). 2. Methods : The Dong-Mu's interpretation on the first chapter of "The Doctrine of Mean(中庸)", and the related contents of Nature and Emotion(性情) in his literature such as "Gyukchigo(格致藁)", "Donguisusebowon-Sasang chobongyun(東醫壽世保元四象草本卷)" and "Donguisusebowon(東醫壽世保元)" were reviewed. 3. Results and Conclusions : 1. Dong-Mu reinterpreted the concepts about 'Providence(天命) and Human Nature(人性)', 'Not-yet-intentional state(未發) and Intentional state(已發)', 'Nature and Mind(性情)' and 'Equilibrium and Harmony(中和)' in "The Doctrine of Mean", and used these concepts as logical tools in explanation of his thoughts of Human being and medical theory. 2. The generating principle of Nature and Mind(性情) presented as sorrow, anger, joy and pleasure is 'the Principle of Human nature(性理)', which is embodied as 'the Principle of Organ(臟理)' in "Donguisusebowon". The Principle of Organ(臟理) is originated from Heart and lie at lung, spleen, liver and kidney as the form of Four Virtue(四德). 3. The Principle of Organ(臟理) has the position of superintendence and is the generating principle of Nature and Emotion(性情), by which the structural and functional variations between different constitutional types are formed. 4. Dong-Mu's newly established concept of Nature and Emotion(性情) is the core logic in his idea of physiology, pathology and self-cultivation.

• Computational Structural Engineering
• /
• v.10 no.4
• /
• pp.315-325
• /
• 1997

This paper describes the application of discretized continuum-type optimality criteria (DCOC) and the development of optimum design program for the multispan partially prestressed concrete beams. The cost of construction as objective function which includes the costs of concrete, prestressing steel, non-prestressing steel and formwork is minimized. The design constraints include limits on the maximum deflection, flexural and shear strengths, in addition to ductility requirements, and upper and lower bounds on design variables as stipulated by the design Code. Based on Kuhn-Tucker necessary conditions, the optimality criteria are explicitly derived in terms of the design variables-effective depth, eccentricity of prestressing steel and non-prestressing steel ratio. The prestressing profile is prescribed by parabolic functions. The self-weight of the structure is included in the equilibrium equation of the real system, as is the secondary effect resulting from the prestressing force. An iterative procedure and computer program for updating the design variables are developed. Two numerical examples of multispan PPC beams with rectangular cross-section are solved to show the applicability and efficiency of the DCOC-based technique.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.13 no.5
• /
• pp.820-830
• /
• 1989

The tire inflation and contact problem has been solved by a finite element method. The finite element formulation is derived from the equilibrium equations by the principle of virtual work in the form of an updated Lagrangian formulation for incremental analysis. Then, a contact formulation is added to the finite element formulation to calculate stress state of tire in contact with flat rigid road under the load due to the self-weight of a vehicle. In the finite element analysis, equations of effective material properties are introduced to analyze a plane strain model of the shell-like tire by considering the bending effect of reinforced steel cords. The proposed equations of effective material properties produced stress concentration around the edge of belt layers, which does not appear when other well-known equations of material properties are adopted. The result from the above algorithm demonstrates the validity of the formulation and the proposed equations for the effective elastic constants. The result fully interprets the cause of separation between belt layers by showing the stress concentration.

• Journal of Environmental Science International
• /
• v.29 no.12
• /
• pp.1261-1274
• /
• 2020

The characteristics of ammonia-nitrogen (NH4+-N) adsorption by a zeolitic material synthesized from Jeju scoria using the fusion and hydrothermal method was studied. The synthetic zeolitic material (Z-SA) was identified as a Na-A zeolite by X-ray diffraction, X-ray fluorescence analysis and scanning electron microscopy images. The adsorption of NH4+-N using Jeju scoria and different types of zeolite such as the Z-SA, natural zeolite, and commercial pure zeolite (Na-A zeolite, Z-CS) was compared. The equilibrium of NH4+-N adsorption was reached within 30 min for Z-SA and Z-CS, and after 60 min for Jeju scoria and natural zeolite. The adsorption capacity of NH4+-N increased with approaching to neutral when pH was in the range of 3-7, but decreased above 7. The removal efficiency of NH4+-N increased with increasing Z-SA dosage, however, its adsorption capacity decreased. For initial NH4+-N concentrations of 10-200 mg/L at pH 7, the adsorption rate of NH4+-N was well described by the pseudo second-order kinetic model than the pseudo first-order kinetic model. The adsorption isotherm was well fitted by the Langmuir model. The maximum uptake of NH4+-N obtained from the Langmuir model decreased in the order of Z-CS (46.8 mg/g) > Z-SA (31.3 mg/g) > natural zeolite (5.6 mg/g) > Jeju scoria (0.2 mg/g).

• Korean small business review
• /
• v.41 no.3
• /
• pp.95-106
• /
• 2019

The Economic Gab-Jil, where the stronger are forcing the weaker to sacrifice, is not only a serious social problem, but also it exhausts the vitality of the national economy. Especially, the issue of 'cost reduction (CR) of delivery price' in automobile industry, and the issue of 'tolls' and 'retaliating' in the franchise business are becoming more controversial. This paper suggests some measures to rectify the problems by an analysis using a game-theoretic model. One of the ways to change the 'bad equilibrium', where economic Gab-Jil is prevalent, to the 'good equiblium' is to strengthen the bargaining power of the weak by legal and institutional measures. It is also a more market-friendly system that is self-enforcing, where the regulation is automatically enforced by the incentives of the participants, without relying solely on the enforcement power of regulatory or supervisory bodies

• Structural Engineering and Mechanics
• /
• v.87 no.3
• /
• pp.255-272
• /
• 2023

Spatial cable systems can provide more transverse stiffness and torsional stiffness without sacrificing the vertical bearing capacity compared with conventional vertical cable systems, which is quite lucrative for long-span earth-anchored suspension bridges' development. Higher economy highlights the importance of refined form-finding analysis. Meanwhile, the internal connection between the lateral and vertical sags has not yet been specified. Given this, an analytic algorithm of form-finding for the earth-anchored suspension bridge with spatial cables is proposed in this paper. Through the geometric compatibility condition and mechanical equilibrium condition, the expressions for cable segment, the recurrence relationship between catenary parameters and control equations of spatial cable are established. Additionally, the nonlinear general reduced gradient method is introduced into fast and high-precision numerical analysis. Furthermore, the analytic expression of the lateral and vertical sags is deduced and discussed. This is very significant for the space design above the bridge deck and the optimization of the sag-to-span ratio in the preliminary design stage of the bridge. Finally, the proposed method is verified with the aid of two examples, one being an operational self-anchored suspension bridge (with spatial cables and a 260 m main span), and the other being an earth-anchored suspension bridge under design (with spatial cables and a 500 m main span). The necessity of an iterative calculation for hanger tensions on earth-anchored suspension bridges is confirmed. It is further concluded that the main cable and their connected hangers are in very close inclined planes.