• Title/Summary/Keyword: Initial condition

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A Study on Combustion Characteristics of Starch (전분 분진의 연소특성에 관한 연구)

  • 김정환;현성호;이창우
    • Fire Science and Engineering
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    • v.15 no.2
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    • pp.1-5
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    • 2001
  • We had investigated combustion properties of starch. Decomposition of starch scavenged by pre-cipitator of spinning factory with temperature were investigated using DSC and TGA. Combustion properties of starch according to amount were checked as temperature variation according to time using spontaneous ignition apparatus. Moreover, combustion properties with blowing or without blowing condition were checked in spontaneous ignition apparatus. As results of thermal analyses, increase in raising temperature causes initial smoldering temperature to move towards low temperature section. In addition, as amount of starch was increased, initial smoldering temperature was lowered. All of combustion forms were smoldering combustion. Initial smoldering temperature was low more slightly with blowing condition than without blowing condition in spontaneous ignition apparatus, which condition made heating value high.

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Investigation of the Condition of Acetic Acid Fermentation with High Concentration Ethanol Resistant Acetobacter sp. FM-10 (고농도 에탄올 내성균 Acetobacter sp. FM-10을 이용한 초산 발효조건 검토)

  • 박권삼;이명숙;목종수;장동석
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.23 no.5
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    • pp.845-848
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    • 1994
  • The fermenting conditions for acetic acid production with Acetobacter sp. FM-10 which could grow in the medium containing 10% ehtanol were investigated. Initial concentration of acetic acid in broth medium affected greatly to the fermentation speed. For example , the acetic acid production increased proportionally by the increasing of initial concentration was higher that 1.0%. When the cultivation was started with broth medium containing 5% ethanol, the additional adding ethanol during the fermentation was not significantly increased the acidity of the medium. The acidity of the medium containing 10% ethanol was reached to 8.3% after shaking than static cultivation by about 10 days with 150 rpm shaking speed. Acetic acid production with shaking cultivation was faster the static cultivation by abot 10 days under the same condition except shaking. In acetic acid fermentation with the batch style fermentor , the optimum fermentation condition was 700 rpm of agitation speed and 5L/min air flow rate in 3L culture medium .

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GLOBAL EXISTENCE FOR 3D NAVIER-STOKES EQUATIONS IN A LONG PERIODIC DOMAIN

  • Kim, Nam-Kwon;Kwak, Min-Kyu
    • Journal of the Korean Mathematical Society
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    • v.49 no.2
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    • pp.315-324
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    • 2012
  • We consider the global existence of strong solutions of the 3D incompressible Navier-Stokes equations in a long periodic domain. We show by a simple argument that a strong solution exists globally in time when the initial velocity in $H^1$ and the forcing function in $L^p$([0; T);$L^2$), T > 0, $2{\leq}p{\leq}+\infty$ satisfy a certain condition. This condition common appears for the global existence in thin non-periodic domains. Larger and larger initial data and forcing functions satisfy this condition as the thickness of the domain $\epsilon$ tends to zero.

A Development of Learning Control Method for the Accurate Control of Industrial Robot (산업용 로봇트의 정밀제어를 위한 학습제어 방법의 개발)

  • 원광호;허경무
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.346-346
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    • 2000
  • We proposed a method of second-order iterative learning control with feedback, which shows an enhancement of convergence speed and robustness to the disturbances in our previous study. In this paper, we show that the proposed second-order iterative learning control algorithm with feedback is more effective and has better convergence performance than the algorithm without feedback in the case of the existence of initial condition errors. And the convergence woof of the proposed algorithm in the case of the existence of initial condition error is given in detail, and the effectiveness of the Proposed algorithm is shown by simulation results.

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Effects by Bracing Reinforcement on Bifurcation of Cable Domes (케이블 돔 구조물의 분기좌굴에 대한 브레이싱 보강 효과)

  • 김민정;백인성;김형석;김승덕
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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    • pp.167-174
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    • 2001
  • A shape resistant shell structure is an extremely efficient mechanical creation because it transmits forces mainly by in-plane forces, but at a certain load level it changes from a stable condition to an unstable condition or vise versa. The instability phenomenon of Geiger-type cable dome structure is generated due to the in-plane twisting near critical load level. Therefore the effect of bracing reinforcement is investigated for the Geiger-type model reinforced by bracing. The effect of initial imperfection is also studied since the structural instability behavior characteristic of shell-like structure is significantly sensitive according to the initial condition.

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UPFC model for power flow using IPLAN (IPLAN을 이용한 UPFC 조류계산 모형)

  • Kook, Kyung-Soo;Kim, Hak-Man;Jeon, Jin-Hong;Oh, Tae-Kyoo;Jang, Byung-Hoon;Chu, Jin-Bu
    • Proceedings of the KIEE Conference
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    • 1998.11a
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    • pp.316-318
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    • 1998
  • This paper presents an approach that provides an equivalent initial operating condition of UPFC in load-flow study for stability analysis. The UPFC model for load-flow implemented by IPLAN in PSS/E is represented by an equivalent load injection. In doing so, the transmission line to which UPFC is connected is disconnected and the function of UPFC is represented by the equivalent load variation. This operating condition may not be adequate as an initial condition for subsequent dynamic simulation. The proposed approach provides a way of equivalencing UPFC load injection without line disconnection. The method was applied to a realistic power system for validity.

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THE EXTENSION OF SOLUTIONS FOR THE CAUCHY PROBLEM IN THE COMPLEX DOMAIN II

  • Lee, Eun-Gu;Kim, Dohan
    • Bulletin of the Korean Mathematical Society
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    • v.30 no.1
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    • pp.29-34
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    • 1993
  • J. Leray [7] proposed a sufficient condition ofr the solvability of the Cauchy problem on the initial hyperplane x$_{1}$=0 with Cauchy data which are holomorphic with respect to the variables parallel to some analytic subvariety S of the initial hyperplane. Limiting the problem to the case of operators with constant coefficients, A. Kaneko [2] proposed a new sharper sufficient condition. Later we generalized this condition and showed that it is necessary and sufficient for the solvability of the Cauchy problem for the hyperfunction Cauchy data and the distribution Cauchy data which contain variables parallel to S as holomorphic parameters in [5, 6]. In this paper, we extend the results in [6] to the case of operators with variable coefficients and show that it is sufficient for the solvability of the Cauchy problem for the hyperfunction Cauchy data. Our main theorem can be considered as an example of a deep theorem on micro-hyperbolic systems by Kashiwara-Schapira [4] and we give a direct proof based on an elementary sweeping out procedure developed in Kaneko [3].

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Sensitivity Evaluation of Physics and Initial Condition of WRF for Ultra Low Altitude Wind Prediction (초저고도 바람예측을 위한 WRF의 물리과정 및 초기조건 민감도 평가)

  • Kwon, JaeIl;Kim, Ki-Young;Ku, SungKwan;Hong, SeokMin
    • Journal of Advanced Navigation Technology
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    • v.23 no.6
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    • pp.487-494
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    • 2019
  • Recently, interest in and use of drones is increasing. In this study, to provide accurate wind prediction at ultra low altitudes of 150 meters or below, the sensitivity of the physical process parameterization and initial conditions was assessed to select the optimal physical process and initial conditions. For this purpose, GFS and LDAPS data were used as initial and boundary conditions, and 7 experiments were constructed using a combination of PBL schemes such as YSU, RUC, ACM2, and LSM such as Noah, RUC, and Pleim. The experiment conducted for 1 month in April 2018. As a result, the RUC-YSU physical process combination using the GFS initial data showed the best performance. This study is meaningful in establishing an optimal modeling method for ultra low altitude wind prediction through experiments using different initial conditions and combination of physical processes.

Post-buckling Behaviour of Aluminium Alloys Rectangular Plate Considering the Initial Deflection Effect (초기 처짐 영향을 고려한 알루미늄 합금 사각형 판의 좌굴 후 거동)

  • Oh, Young-Cheol;Kang, Byoung-Mo;Ko, Jae-Yong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.20 no.6
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    • pp.738-745
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    • 2014
  • In this paper, It is performing to the elastic and elasto-plastic large deformation series analysis using a numerical method for the initial deflection effect of the aluminum alloy rectangular plate in the elasto-plastic loading area patch loading size. It is assumed a boundary condition to be a simply supported condition and consider the initial deflection amplitude, aspect ratio. It examined the critical elastic buckling load and post-buckling behaviour of aluminium alloy A6082-T6 rectangular plate. It used a commercial program for the elastic and elasto-plastic deformation series analysis. If the initial deflection amplitude is smaller, the in-plane rigidity with increasing to load is reduced from the start and occurs significantly more increasing the amplitude. More higher the aspect ratio, the initial yield strength is gradually decreased, and the plate thickness thicker and occurs larger than the thin walled plate a reduction ratio of the initial yield strength of the patch loading size as 0.5.

Construction of a Support System for Determining the Condition of Injection Molding (사출성형 조건 설정 지원시스템 구축)

  • Yi Il-Lang;Kim Bo-Hyun;Baek Jae-Yong
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.3 s.168
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    • pp.68-77
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    • 2005
  • The set-up of an injection molding process is a ye complicated and time-consuming job because it is required to well determine a lot of variables closely related to products. Thus, the productivity of the set-up process mainly depends on operators' expertise and know-how. To solve the problem mentioned before, this research constructs a support system which helps operators determining the condition of the injection molding easily and systematically. The construction of the support system consists of the following four steps: 1) to determine the control variables which affect the target defect types, 2) to design and implement UI(user interface) using a scenario of set-up process, 3) to design and implement the search algorithms for the initial and optima] condition, and 4) to construct the embedded system which integrates the support system with the operating system of a plastic injection molding machine. The test experiments of some typical products are performed using the embedded system to verify the validity of the support system.