• Geomechanics and Engineering
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• v.38 no.2
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• pp.139-155
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• 2024

The piled raft foundations are subjected to lateral loading under the action of wind and earthquake loads. Their bearing behavior and flexural responses under these loadings are of prime concern for researchers and practitioners. The insufficient experimental studies on piled rafts subjected to lateral loading lead to a limited understanding of this foundation system. Lateral load sharing between pile and raft in a laterally loaded piled raft is scarce in literature. In the present study, lateral load-displacement, load sharing, bending moment distribution, and raft inclinations of the piled raft foundations have been discussed through an instrumented scaled down model test in 1 g condition. The contribution of raft in a laterally loaded piled raft has been evaluated from the responses of pile group and piled raft foundations attributing a variety of influential system parameters such as pile spacing, slenderness ratio, group area ratio, and raft embedment. The study shows that the raft contributes 28-49% to the overall lateral capacity of the piled raft foundation. The results show that the front pile experiences 20-66% higher bending moments in comparison to the back pile under different conditions in the pile group and piled raft. The piles in the piled raft exhibit lower bending moments in the range of 45-50% as compared to piles in the pile group. The raft inclination in the piled raft is 30-70% less as compared to the pile group foundation. The lateral load-displacement and bending moment distribution in piles of the single pile, pile group, and piled raft has been presented to compare their bearing behavior and flexural responses subjected to lateral loading conditions. This study provides substantial technical aid for the understanding of piled rafts in onshore and offshore structures to withstand lateral loadings, such as those induced by wind and earthquake loads.

• Journal of the Korean Society for Railway
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• v.10 no.1 s.38
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• pp.51-56
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• 2007

In this paper, control schemes are developed for a propulsion system(Converter/Inverter) in electrical train. A robust controller for PWM converter is proposed. The converter controller consists of a PI controller for DC output voltage and a current controller using error-space approach for maintaining the sinusoidal current waveform and unity power factor. This proposed method is based on characteristic ratio assignment(CRA) method which has the advantage to design the optimal gain to meet the referenced response and overshoot within the limit range. Inverter system is controlled by vector control and slip frequency control. At low speed region, vector control scheme is applied to control instantaneous torque and slip frequency control is performed under overmodulation region and one pulse mode. Because output voltage of converter contains harmonics ripple at twice input ac line frequency, control scheme is developed to reduce the pulsating torque current. The performance of propulsion system will be verified by simulation and prototype experimental results.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.119-120
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• 2000

Influences of sustain voltage on wall charges and wall voltages are experimentally investigated in surface AC plasma display panels(AC-PDPs), in which electrode gap and width are $80\;{\mu}m$ and $270\;{\mu}m$, respectively. The filling gas is Ne-Xe gas mixture, and total pressures 300 Torr. Also it is found that the more amount of Xe mixing ratio makes the less wall charge and voltage for sustain voltage ranged from 140 V to 222 V. The response time has been delayed by adding a small amount of Xe to Ne in comparison with that without Xe. It is also found that the wall charge and voltage are reduced by adding a small amount of Xe to Ne in comparison with those without Xe.

• Asian-Australasian Journal of Animal Sciences
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• v.4 no.1
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• pp.91-97
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• 1991

Twenty five 75% Holstein Friesian cross bred bullocks fed rice straw (Oryza sativa) of long form, were fed with the following five treatments. 1. Rice straw, untreated (RS) 2. RS + water (1:1), stored for 24 hours (WRS) 3. RS (100 kg) + urea solution (4 kg urea/100 litre water) and dried (USRS) 4. RS (100 kg) + urea solution (as in 3) stored in wet condition for 24 hours (UWRS) 5. RS (100 kg) + urea solution (as in 3) stored in pit for 21 days (UTRS). Potential digestibility of treatments of RS was evaluated by monitoring (in vitro) Simulating Rumen like Fermentation (SRLF). The results indicated that Dry Matter Intake (DMI), digestibility of nutrients, N utilization were of the order UTRS > UWRS > USRS > WRS and RS (p < 0.05 to p < 0.01). SRLF index was high (255.84) for UTRS and least (145.58) for USRS. It was intermediary (199.66) for UWRS. The acetyl content (AC) of UTRS with higher hemicellulose (HCE) digestibility (80.8%) was low compared to UWRS, USRS, RS and WRS. The acetate content was of the order UTRS < UWRS < USRS < WRS and RS thereby indicating that reduction in acetyl content was an index of positive response of urea-treatment of RS. In addition, the ratio of HCE/AC in faeces of UTRS was 0.87 as against the ratios (2.26-2.48) observed in other treatments recording reduction in AC due to urea-treatment. Among the treatments, USRS only supplemented N while UTRS in addition to utilization N, increased the digestibility of structural carbohydrates. Reduction in treatment time from 21 days to 1 day (UWRS) resulted in improvements similar to those of UTRS.

• Journal of the Korea Institute of Building Construction
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• v.2 no.4
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• pp.89-98
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• 2002

Self-leveling material(SLM) is one of the floor finishing materials which make flat surface like as water level by itself in a short time. So it is possible to increase construction speed and enhance economical efficiency In this study, author intended to develop SLM for the industrial warehouse and factory loading heavy weight machinery and vehicles. The demanded properties for this type of SLM are above 200mm of flow value and above 300kgf/$cm^2$ of 28-days compressive strength. To possess demended strength and fluidity, SLM have to be composed of many types of binders and chemical additives. So it is difficult to decide suitable mixing proportion of composition materials. In this study, author investigated the weight percentage effect of main composition materials for high-strength self-leveling material, by experimental design such as tables of orthogonal arrays and simplex design, and by statistical analysis such as analysis of variance and analysis of response surface. Variables of experiments were ordinary Portland cement(OPC), alumina cement(AC), anhydrous gypsum(AG), lime stone(LS) and sand, and properties of tests were fluidity of fresh state and strength of hardened state. Results of this study are showed that suitable mix proportions of binders for the high strength self-leveling materials are two groups. One is 78~85.5% OPC, 7.5~9.5% AC, 9~12.5% AG and the other is 72.5~78% OPC, 9~12.5% AC, 13~15% AG.

• The Journal of Korean Medicine
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• v.29 no.1
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• pp.156-166
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• 2008

Objective : Pamooltang (PM) and Sipjeondaebotang (SC) are used in Korea to treat many diseases such as sterility, menstrual disorder, and general prostration. We made a comparative study of PM and SC which are different in component ratio between Astragalus membranaceus BUNGE (AC) and Cinnamomum cassia PRESL. (CC). Methods : Anti-oxidation was studied by 1.1.-diphenyl-2-picrylhydrazyl (DPPH) assay and anti-inflammation was investigated by prostaglandin $E_2\;(PGE_2)$ and nitric oxide (NO) inhibition assay. For immune response activities, this study used NO synthesis on RAW 264.7 cells and splenocyte proliferation. Results : The results showed that PM and SC components had no significant effect of anti-oxidation or anti-inflammation. However, we observed their effects upon inducible NO synthesis in Raw 264.7 cells. The SC2 stimulated NO synthesis $11.42\pm1.36{\mu}M$ (control; $0.89\pm0.00{\mu}M$). PM and SC components had the effect of immune response which in a dose-dependent manner significantly induced the splenocyte proliferation. The splenocyte proliferation induced by SC2 was higher than others at the concentration of 1, 10, 100, 1000 and 2000 ${\mu}g/ml$. The SC8 was shown to up-regulate IgG, 100 ${\mu}g/ml$ 3.3 times, 1000 ${\mu}g/ml$ 2.6 times as a control. Conclusions : These results may have important implications for our understanding of the ratios of AC and CC in SC.

• Korean journal of applied entomology
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• v.33 no.1
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• pp.26-32
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• 1994

Electroantennography, wind tunnel observation, and field trapping experiments were carried out to investigate the biological activity of synthetic sex pheromone in the onental tobacco budworm. Heli-couerpa assulta. Two major sex pheromone components of H. assulta, Z9-16' Ald and Z11-16: Ald. elicited a big EAG response in male, but not in female Their mIXture ratios did not give much influence on EAG size Fema]e H assulta showed a great EAG response only to its host plant e extract. EAG size also increased with the amount of mixture from 001 to 10 [lg but rather decreased w when the amount was 1 00 $\mug$. H. assulta always revealed a series of stereotyped behavior in a wind tunnel. The behavioral response was different when the males were stimulated with the sex pheromone containing some minor components, 16: AId and Z9.16: Ac, or being different in mixing ratios of the two major components. The best ratio of the sex phemmone components for a attracting H assulta male adults was 20-25: 1 between Z9-16: Aid and Z11-16: Ald in net house a and red pepper field experiments in Korea When the lure contamed Z9-16: OH, attracting power rapidly decreased. The synthetic sex pheromone showed a strong attraction when compared to virgin females

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1064_1065
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• 2009

PV (Photovoltaic) power generation system has been widely studied as a clean and renewable power source. Tracking the MPP (maximum power point) of a PV array is usually an essential part of a PV system. This paper describes POS (Photovoltaic Output Sensorless) MPPT method and optimization technique of its operational characteristics for grid-connected PV generation system. A DC-DC converter has been used to step-up the PV voltage and DC-AC converter has been used for connecting the system to the grid. Optimization technique has been implemented to optimize the current and voltage controller gain parameters and duty ratio increment of DC-DC converter. Simulation results reveal that the proposed control has better response.

• Journal of the Korean Chemical Society
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• v.31 no.2
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• pp.162-167
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• 1987

Four component $Ag_2S$-PbS-$PbHAsO_4-Cu_2S$ and three component $Ag_2S$-PbS-$PbHAsO_4$ electrodes have been prepared and evaluated for the direct measurement of monohydrogen arsenate. The 3.0 : 0.5 : 1.0 : 0.25 (mole ratio, $Ag_2S$:PbS:$PbHAsO_4:Cu_2S$) composition is superior in terms of potentiometric response, stability, rapidity of response and reproducibility. Testing was done over the concentration range $10^{-1}$~$10^{-4}M\;HA_SO_4^{2-}$in 0.1F NH4Ac-NH4OH buffer solution at pH 8.50 with constant ionic strength. Interfering ions were $CN^-,\;I^-,\;S^{-2}$ and $Cl^-$.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1663-1668
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• 2017

A BLDC motor with higher number of phases has several advantages, compared to the conventional three-phase BLDC motors. It can reduce the commutation torque ripple and the iron loss without increasing the voltage per phase and increase the reliability and power density. Higher number of phases increase the torque-per-ampere ratio for the same machine volume and output power by widening the electrical conduction period. In this paper, the proposed seven-phase BLDC motor drive system is made into several functional modular blocks, so that it can be easily extended to other ac motor applications: back-EMF block, hysteresis current control block, pwm inverter block, phase current block, and speed/torque control block. Also in a system of BLDC motor drive, the PI controller has been widely used in the speed controller because of the simple implementation. To obtain a good speed response in a general drive system using the PI controller, the high bandwidth of a controller is established. therefore, in this paper, a Fuzzy controller is applied to the 7-phase BLDC motor drive system in order to improve the speed control performance. The Fuzzy controller is compared with a conventional PI controller through the experiment with respect to speed dynamic responses. These experimental results show that the Fuzzy controller of the 7-phase BLDC motor drive system is superior over the conventional PI controller. The algorithm using the Fuzzy controller can improve a comfortable ride in the field of high performance 7-phase BLDC motor drive applications.