• Title, Summary, Keyword: TOT Method

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Free vibration of Levy-type rectangular laminated plates using efficient zig-zag theory

  • Behera, Susanta;Kumari, Poonam
    • Advances in Computational Design
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    • v.3 no.3
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    • pp.213-232
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    • 2018
  • First time, an exact solution for free vibration of the Levy-type rectangular laminated plate is developed considering the most efficient Zig-Zag theory (ZIGT) and third order theory (TOT). The plate is subjected to hard simply supported boundary condition (Levy-type) along x axis. Using the equilibrium equations and the plate constitutive relations, a set of 12 m first order differential homogenous equations are obtained, containing displacements and stress resultant as primary variables. The natural frequencies of a single-layer isotropic, multi-layer composites and sandwich plates are tabulated for three values of length-to-thickness ratio (S) and five set of boundary conditions and further assessed by comparing with existing literature and recently developed 3D EKM (extended Kantorovich method) solution. It is found that for the symmetric composite plate, TOT produces better results than ZIGT. For antisymmetric and sandwich plates, ZIGT predicts the frequency for different boundary conditions within 3% error with respect to 3D elasticity solution while TOT gives 10% error. But, ZIGT gives better predictions than the TOT concerning the displacement and stress variables.

Comparison of OC and EC Measurement Results Determined by Thermal-optical Analysis Protocols (열광학적 분석 프로토콜에 의한 유기탄소와 원소탄소 측정값 비교)

  • Kim, Hyosun;Jung, Jinsang;Lee, Jinhong;Lee, Sangil
    • Journal of Korean Society for Atmospheric Environment
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    • v.31 no.5
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    • pp.449-460
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    • 2015
  • Carbonaceous aerosol is generally classified into OC (organic carbon) and EC (elemental carbon) by thermal optical analysis. Both NIOSH (National institute of occupational safety and health) with high temperature (HighT) and IMPROVE-A (Interagency monitoring of protected visual environments) with low temperature (LowT) protocols are widely used. In this study, both protocols were applied for ambient $PM_{2.5}$ samples (Daejeon, Korea) in order to underpin differences in OC and EC measurements. An excellent agreement between NIOSH and IMPROVE-A protocol was observed for TC (total carbon). However, significant differences between OC and EC appeared and the differences were larger for EC than OC. The main differences between two protocols are temperature profile and charring correction method. For the same charring correction method, HighT_OC was 10% higher than LowT_ OC, while HighT_EC was 15% and 33% lower than LowT_EC for TOT (thermal-optical transmittance) and TOR (thermal-optical reflectance), respectively. This difference may be caused by the temperature of OC4 in He step and possibly difference in POC (pryorilized OC) formation. For the same temperature profile, OC by TOT was about 26% higher than that by TOR. In contrast, EC by TOT was about 50% lower than that by TOR. POC was also dependent on both temperature profile and the charring correction method, showing much distinctive differences for the charring correction method (i.e., POC by TOT to POC by TOR ratio is about 2). This difference might be caused by different characteristics between transmittance and reflectance for monitoring POC formation within filters. Results from this study showed that OC and EC depends on applied analysis protocol as shown other studies. Because of the nature of the thermal optical analysis, it may not be possible to have an absolute standard analysis protocol that is applicable for any ambient $PM_{2.5}$. Nevertheless, in order to provide consistent measurement results for scientists and policy makers, future studies should focus on developing a harmonized standard analysis protocol that is suitable for a specific air domain and minimizes variations in OC and EC measurement results. In addition, future elaborate studies are required to find and understand the causes of the differences.

Fragmentation Fractal Analysis on Particle-size Distribution (Fragmentation 프랙탈을 이용한 입도분포 분석)

  • 민덕기;이완진
    • Journal of the Korean Geotechnical Society
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    • v.19 no.2
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    • pp.199-206
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    • 2003
  • Particle-size distribution in soils is one of the most fundamental physical properties of soils. One of the latest developments in the study of particle-size distributions has focused on the use of fractal theories. In this study, the fragmentation fractals were used for determining the characteristics of the particle-size distribution curve. It was shown that the mass-size distribution method was more practical than the cumulative number-size distribution method. From the co-relation between fractal dimensions($D_{tot}$) and the coefficient of uniformity($C_{u}$), there was a sharp increase in fractal dimensions for $C_{u}$<4, but fractal dimension converged the single value for $D_{u}$$\geq$6. Fractal dimensions were affected by small sized particles for $C_{c}$$\geq$3 and large sized particles for $C_{c}$/<3. As a result of the analysis of the influence of the effective size($D_{10}$), it was observed that the changes of $D_{tot}$/ were nominal beyond the effective size.

Modeling of Electrical Conductivity from $\sigma$tot vs. Po21/4 Plot in Wet Atmosphere for High-Temperature Proton-Conducting Oxides

  • Baek, Hyun-Deok
    • The Korean Journal of Ceramics
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    • v.4 no.2
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    • pp.136-140
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    • 1998
  • This work demonstrates a method for modeling of electrical conductivity in high-temperature proton-conducting oxides. Total conductivity was calculated assuming that it comprises partial conductivities contributed by protons, oxygen ions and electron holes. From the polt $\sigma_{tot}$ vs. $po_2\;{1/4}$ in wet atmosphere, thermodynamic and kinetic parameters were obtained representing transport properties such as concentration and mobility of the charge-carrying defects. The formulas for the calculation of partial conduction were derived based on the defect structure of HTPCs. Illustrative calculation were made for $SrCe_{0.95}Yb_{0.05}O_{2.975}$ system.

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Binding Energy in the n-type Al2Gax-1A3-GaAs Quantum well according to the Trial function (Al2Gax-1A3-GaAs 양자우물에서 시도함수에 따른 결합에너지)

  • Lee, Kun-Young;Lee, Mu-Sang;Chun, Sang-Kook
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.9
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    • pp.781-786
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    • 2005
  • The binding energy in the n-type $GaAs/Al_xGa_{1-x}As$ quantum well is calculated. The shooting method, modified from the finite difference method, is used for the calculation of the subband energy level and its wave function. In order to account tot the change of the potential energy due to the charged particles, impurities and electrons, the self consistent method is employed. The wave function used for the calculation of the binding energy is assumed to be composed of the envelope function and hydrogenic 1s function. Then, the binding energies calculated by taking into account lot two different types of the hydrogenic 1s function are compared.

Fuzzy Moving Sliding Model Control for Robotic Manipulators (로봇 매니퓰레이터를 위한 퍼지 이동슬라이딩 모드 제어)

  • Chun, Kyung-Han;Park, Bong-Yeol
    • Journal of Institute of Control, Robotics and Systems
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    • v.7 no.7
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    • pp.597-604
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    • 2001
  • Recently, the study of the moving sliding mode in the variable structure control is in progress ac-tively. The conventional time-invariant sliding model control can\`t guarantee the sliding mode in the reaching phase, which is robust against the uncertainty. But with the time-varying method, the controller makes the states track the desired trajectories and keeps the sliding mode. Nevertheless, the piecewise continuous method of the past still has the reaching mode. Thus we propose the continuously moving sliding surface by the fuzzy algorithm. The proposed algorithm is made of the fuzzy rule considering both the error and the error velocity, and may apply to the entire phase plane without sacrificing sliding mode. Especially the proposed scheme can rotate tot he slope-decreasing direction, needless to say rotating to the slope-increasing direction. For showing that the proposed controller guarantees the sliding model and ensures the robustness, we apply the proposed method to the two-link robot manipulator simulation.

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Comparison of Measurements of Airway Resistance during Panting and Quiet Breathing (Panting 및 Quiet Breathing시 Airway Resistance 측정의 비교)

  • Cheon, Seon-Hee;Lee, Woo-Hyung;Lee, Kee-Young;Kim, Se-Kyu;Chang, Joon;Kim, Sung-Kyu;Lee, Won-Young
    • Tuberculosis and Respiratory Diseases
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    • v.40 no.3
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    • pp.267-273
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    • 1993
  • Background: Panting method for airway resistance measurement has the disadvantages of departing from the normal breathing pattern and of difficult for some patients to perform. We can measure airway resistance during quiet breathing under more physiologic conditions. Airway resistance is often measured during panting but attempts have been made to facilitate resistance measurements during quiet breathing. This study was designed to compare airway resistance measurements during panting with those during quiet breathing. Method: The 24 normal persons and 29 pulmonary disease patients were included in this study. Spirometry was performed and airway resistance measurement was also done during panting and quiet breathing concomittently. Results: The results were as follows; 1) High correlations were found between airway resistance measurements during panting and quiet breathing. 2) Resistance fell during panting, 21.2% in Raw tot, and 22.1% in Raw 0.5. 3) In normal persons, airway resistance fell more during panting when comparing to those in pulmonary disease patients. 4) This was largely independent of thoracic gas volume differences, because the specific airway conductance rose significantly during panting 5) The patients in whom resistance didn't fell during panting was supposed to the patients who couldn't perform panting successively because of high resistance. Conclusions: Although airway resistance can be measured during panting or quiet breathing according to the patient's performance, we must consider resistance fell during panting, by a mean 20%. It may be concluded that quiet breathing is more likely than panting to provide a relevant measurement of airway resistance.

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The Effect of Pressure Support on Respiratory Mechanics in CPAP and SIMV (CPAP 및 SIMV Mode하에서 Pressure Support 사용이 호흡역학에 미치는 효과)

  • Lim, Chae-Man;Jang, Jae-Won;Choi, Kang-Hyun;Lee, Sang-Do;Koh, Youn-Suck;Kim, Woo-Sung;Kim, Dong-Soon;Kim, Won-Dong;Park, Pyung-Whan;Choi, Jong-Moo
    • Tuberculosis and Respiratory Diseases
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    • v.42 no.3
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    • pp.351-360
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    • 1995
  • Background: Pressure support(PS) is becomimg a widely accepted method of mechanical ventilation either for total unloading or for partial unloading of respiratory muscle. The aim of the study was to find out if PS exert different effects on respiratory mechanics in synchronized intermittent mandatory ventilation(SIMV) and continuous positive airway pressure (CPAP) modes. Methods: 5, 10 and 15 cm $H_2O$ of PS were sequentially applied in 14 patients($69{\pm}12$ yrs, M:F=9:5) and respiratory rate (RR), tidal volume($V_T$), work of breathing(WOB), pressure time product(PTP), $P_{0.1}$, and $T_1/T_{TOT}$ were measured using the CP-100 pulmonary monitor(Bicore, USA) in SIMV and CPAP modes respectively. Results: 1) Common effects of PS on respiratory mechanics in both CPAP and SIMV modes As the level of PS was increased(0, 5, 10, 15 cm $H_2O$), $V_T$ was increased in CPAP mode($0.28{\pm}0.09$, $0.29{\pm}0.09$, $0.31{\pm}0.11$, $0.34{\pm}0.12\;L$, respectively, p=0.001), and also in SIMV mode($0.31{\pm}0.15$, $0.32{\pm}0.09$, $0.34{\pm}0.16$, $0.36{\pm}0.15\;L$, respectively, p=0.0215). WOB was decreased in CPAP mode($1.40{\pm}1.02$, $1.01{\pm}0.80$, $0.80{\pm}0.85$, $0.68{\pm}0.76$ joule/L, respectively, p=0.0001), and in SIMV mode($0.97{\pm}0.77$, $0.76{\pm}0.64$, $0.57{\pm}0.55$, $0.49{\pm}0.49$ joule/L, respectively, p=0.0001). PTP was also decreased in CPAP mode($300{\pm}216$, $217{\pm}165$, $179{\pm}187$, $122{\pm}114cm$ $H_2O{\cdot}sec/min$, respectively, p=0.0001), and in SIMV mode($218{\pm}181$, $178{\pm}157$, $130{\pm}147$, $108{\pm}129cm$ $H_2O{\cdot}sec/min$, respectively, p=0.0017). 2) Different effects of PS on respiratory mechanics in CP AP and SIMV modes By application of PS (0, 5, 10, 15 cm $H_2O$), RR was not changed in CPAP mode($27.9{\pm}6.7$, $30.0{\pm}6.6$, $26.1{\pm}9.1$, $27.5{\pm}5.7/min$, respectively, p=0.505), but it was decreased in SIMV mode ($27.4{\pm}5.1$, $27.8{\pm}6.5$, $27.6{\pm}6.2$, $25.1{\pm}5.4/min$, respectively, p=0.0001). $P_{0.1}$ was reduced in CPAP mode($6.2{\pm}3.5$, $4.8{\pm}2.8$, $4.8{\pm}3.8$, $3.9{\pm}2.5\;cm$ $H_2O$, respectively, p=0.0061), but not in SIMV mode($4.3{\pm}2.1$, $4.0{\pm}1.8$, $3.5{\pm}1.6$, $3.5{\pm}1.9\;cm$ $H_2O$, respectively, p=0.054). $T_1/T_{TOT}$ was decreased in CPAP mode($0.40{\pm}0.05$, $0.39{\pm}0.04$, $0.37{\pm}0.04$, $0.35{\pm}0.04$, respectively, p=0.0004), but not in SIMV mode($0.40{\pm}0.08$, $0.35{\pm}0.07$, $0.38{\pm}0.10$, $0.37{\pm}0.10$, respectively, p=0.287). 3) Comparison of respiratory mechanics between CPAP+PS and SIMV alone at same tidal volume. The tidal volume in CPAP+PS 10 cm $H_2O$ was comparable to that of SIMV alone. Under this condition, the RR($26.1{\pm}9.1$, $27.4{\pm}5.1/min$, respectively, p=0.516), WOB($0.80{\pm}0.85$, 0.97+0.77 joule/L, respectively, p=0.485), $P_{0.1}$($3.9{\pm}2.5$, $4.3{\pm}2.1\;cm$ $H_2O$, respectively, p=0.481) were not different between the two methods, but PTP($179{\pm}187$, $218{\pm}181 cmH_2O{\cdot}sec/min$, respectively, p=0.042) and $T_1/T_{TOT}$($0.37{\pm}0.04$, $0.40{\pm}0.08$, respectively, p=0.026) were significantly lower in CPAP+PS than in SIMV alone. Conclusion: PS up to 15 cm $H_2O$ increased tidal volume, decreased work of breathing and pressure time product in both SIMV and CPAP modes. PS decreased respiration rate in SIMV mode but not in CPAP mode, while it reduced central respiratory drive($P_{0.1}$) and shortened duty cycle ($T_1/T_{TOT}$) in CPAP mode but not in SIMV mode. By 10 em $H_2O$ of PS in CPAP mode, same tidal volume was obtained as in SIMV mode, and both methods were comparable in respect to RR, WOB, $P_{0.1}$, but CPAP+PS was superior in respect to the efficiency of the respiratory muscle work (PTP) and duty cycle($T_1/T_{TOT}$).

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Optimal Design and fabrication of Prototype DC Reactor for Inductive Superconducting fault Current Limiter (유도형 고온초전도 한류기용 Prototype 직류 리액터의 설계와 제작)

  • 김태중;강형구;고태국
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.12S
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    • pp.1292-1298
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    • 2003
  • In this paper, dc reactor lot the inductive high-Tc superconducting fault current limiter (SFCL) was optimally designed by finite element method(FEM). The Prototype high-Tc do reactor was manufactured and compared to the results of design. This dc reactor consists of 4∼stacked double pancake coils which are wounded with Bi-2223 wire coated with SUS315L. Kapton tape is used for the insulation of turn to turn and layer to layer. Each pancake is connected in series by soldering Finally, optimal design and manufacture method lot the dc reactor is suggested in this paper. Through the comparison of result of optimal design and experimental result of prototype high-Tc superconducting dc reactor, reliance on the design of the high-Tc dc reactor tot the 1.2 kV/80 A SFCL is proved.

Study on the Prediction of Ground-Borne Vibration with Distance induced by Subway Transit System (지하철에 의한 거리별 지반진동 예측에 관한 연구)

  • 김득성;김형곤;장서일
    • Proceedings of the KSR Conference
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    • pp.597-602
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    • 2002
  • This study reviews several of the procedures that have been used to predict ground-born vibration. The vibration responses are measured at three sites that have different soil qualities. The measured vibration levels are compared with the predicted results by previously used vibration level prediction models. In this study a numerical method, which is based on explicit differential method, is used to compensate tot existing prediction models. Although numerically computed results are not quantitatively in good agreement with the measured results, the trends are comparable in the sense that vibration level does not decrease monotonically with distance. Also, The site with the deepest tunnel gives the highest vibration level.

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