• Journal of applied mathematics & informatics
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• v.24 no.1_2
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• pp.261-271
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• 2007

The symbol C($m_1^{n_1}m_2^{n_2}{\cdots}m_s^{n_s}$) denotes a 2-regular graph consisting of $n_i$ cycles of length $m_i,\;i=1,\;2,\;{\cdots},\;s$. In this paper, we give some construction methods of cyclic($K_v$, G)-designs, and prove that there exists a cyclic($K_v$, G)-design when $G=C((4m_1)^{n_1}(4m_2)^{n_2}{\cdots}(4m_s)^{n_s}\;and\;v{\equiv}1(mod\;2|G|)$.

• Journal of the Korean Electrochemical Society
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• v.3 no.4
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• pp.241-245
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• 2000

The objective of this work Is to design, fabricate, and characterize pseudo-capacitor using amorphous $MnO_2\;nH_2O$ electrode material. The cyclic voltammogram under 100mV/s scan rate of the material shows the electrochemically stable potential window of 1V and the specific capacitance of 250F/g. The TDMA pulse test result indicates that the TDMA system (2 parallel-pseudo-capacitor systems) has the ohmic voltage drop of 0.22V and the capacitor voltage drop of 0.38V. The total voltage drop of the TDMA system is 0.60V and less than 1V of which value is the maximum voltage drop requirement or the TDMA satellite phone. Also, the TDMA system had the ESR of $55m{\Omega}$ and the capacitance of 105mF. Therefore, it is confirmed that the TDMA system has the application feasibility as load-leveling capacitor for the satellite phone.

• Earthquakes and Structures
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• v.20 no.4
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• pp.377-388
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• 2021

Thin perforated Steel Plate Shear Walls (SPSWs) are among the most common types of seismic energy dissipation systems to protect the main boundary components of SPSWs from fatal fractures in the high-risk zones. In this paper, the cyclic behavior of the different circular hole patterns under cyclic loading is reported. Based on the experimental results, it can be concluded that a change in the perforation pattern of the circular holes leads to a change in the locations of the fracture tendency over the web plate, especially at the plate-frame interactions. Accordingly, the cyclic responses of the tested specimens were simulated by finite element method using the ABAQUS package. Likewise, perforated shear panels with a new perforation pattern obtained by implementing Topology Optimization (TO) were proposed. It was found that the ultimate shear strength of the specimen with the proposed TO perforation pattern was higher than that of the other specimens. In addition, theoretical equations using the Plate-Frame Interaction (PFI) method were used to predict the shear strength and initial stiffness of the considered specimens. The theoretical results showed that the proposed reduced coefficients relationships cannot accurately predict the shear strength and initial stiffness of the considered perforated shear panels. Therefore, the reduced coefficients should be adopted in the theoretical equations based on the obtained experimental and numerical results. Finally, with the results of this study, the shear strength and initial stiffness of these types of perforated shear panels can be predicted by PFI method.

• Earthquakes and Structures
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• v.4 no.4
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• pp.429-449
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• 2013

Current Design Codes for Reinforced Concrete (RC) interior beam-column joints are based on limited experimental studies on the seismic behavior of eccentric joints. To supplement existing information, an experimental study was conducted that focused on the effect of eccentricity of the deeper beams with respect to the shallow beams. A total of eight one-third scale interior joints with beams of different depths were subjected to reverse cyclic loading. The primary variables in the test specimens were the amount of joint transverse reinforcement and the cross section of the shallow beams. The overall performance of each test assembly was found to be unsatisfactory in terms of joint shear strength, stiffness, energy dissipation and shear deformation. The results indicated that the vertical eccentricity of spandrel beams in this type of joint led to lower capacity in joint shear strength and severe damage of concrete in the joint core. Increasing the joint shear reinforcement was not effective to alter the failure mode from joint shear failure to beam yielding which is favorable for earthquake resistance design, whereas it was effective to reduce the crack width at the small loading stages. Based on the observed behavior, the shear stress of the joint core was suggested to be kept as low as possible for a safe and practical design of this type of joint.

• Corrosion Science and Technology
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• v.3 no.6
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• pp.245-250
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• 2004

A series of classical G109 type concrete specimens was exposed to cyclic wet and dry ponding with 15 w/o NaCl solution for approximately five years. Mix design variables included 1) three cement alkalinities (EqA of 0.97, 0.52, and 0.36) and 2) three water-cement ratios (0.50, 0.41, and 0.37). To determine the corrosion initiation time, corrosion potential and macro-cell current between top and bottom bars were monitored. Subsequent to corrosion initiation, specimens were autopsied and visually inspected. Concrete powder samples were collected from top rebar trace and chloride concentration was measured. Also, time-to-corrosion, $T_i$, for specimens of the individual mix designs was represented using Weibull analysis. Time-to-corrosion was a distributed parameter; and because of this, corrosion initiation of four identical specimens for each mix varied, often over a relatively wide range. Specimens fabricated using the lowest water cement ratio and the highest alkalinity cement exhibited the longest time-to-corrosion initiation and the highest chloride threshold levels. Time-to-corrosion did not increase monotonically with cement alkalinity, however, presumably as a consequence of relatively high $Cl^-$ binding in the lower pore water pH range. The chloride threshold level, $Cl_{th}$, increased with increasing $T_i$ and, consequently, was greatest for the highest cement alkalinity specimens.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.2
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• pp.43-56
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• 1993

The laboratory tests are performed on how the liquefaction potential of the sea dike structures on the saturated sand or silty sand seabed could be affected due to earthquake before and after construction results are given as follows ; 1. Earthquake damages to sea dike structures consist of lateral deformation, settlement, minor abnormality of the structures and differential settlement of embankments, etc. It is known that severe disasters due to this type of damages are not much documented. Because of its high relative cost of the preventive measures against this type of damages, the designing engineer has much freedom for the play of judgement and ingenuity in the selection of the construction methods, that is, by comparing the cost of the preventive design cost at a design stage to reconstruction cost after minor failure. 2. The factors controlling the liquefaction potential of the hydraulic fill structure are magnitude of earthquake(max. surface velocity), N-value(relative density), gradation, consistency(plastic limit), classification of soil(G & vs), ground water level, compaction method, volumetric shear stress and strain, effective confining stress, and primary consolidation. 3. The probability of liquefaction can be evaluated by the simple method based on SPT and CPT test results or the precise method based on laboratory test results. For sandy or silty sand seabed of the concerned area of this study, it is said that evaluation of liquefaction potential can be done by the one-dimensional analysis using some geotechnical parameters of soil such as Ip, Υt' gradation, N-value, OCR and classification of soils. 4. Based on above mentioned analysis, safety factor of liquefaction potential on the sea bed at the given site is Fs =0.84 when M = 5.23 or amax= 0.12g. With sea dike structures H = 42.5m and 35.5m on the same site Fs= 3.M~2.08 and Fs = 1.74~1.31 are obtained, respectively. local liquefaction can be expected at the toe of the sea dike constructed with hydraulic fill because of lack of constrained effective stress of the area.