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검색결과 723건 처리시간 0.021초

Optimal scheduling for multi-product batch processes under consideration of non-zero transfer times and set-up times

  • Jung, Jae-Hak;Lee, In-Beum;Yang, Dae-Ryook;Chang, Kun-Soo
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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    • pp.30-35
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    • 1993
  • Simple recurrence relations for calculating completion times of various storage polices (unlimited, intermediate storages(FIS), finite intermediate storages(FIS), no intermediate storage(NIS), zero wait(ZW) for serial multi-product multi-unit processes are suggested. Not only processing times but also transfer times, set-up (clean-up) times of units and set-up times of storages are considered. Optimal scheduling strategies with zero transfer times and zero set-up times had been developed as a mixed integer linear programniing(MILP) formulation for several intermediate storage policies. In this paper those with non-zero transfer times, non-zero set-up times of units and set-up times of storages are newly proposed as a mixed integer nonlinear programming(MINLP) formulation for various storage polices (UIS, NIS, FIS, and ZW). Several examples are tested to evaluate the robustness of this strategy and reasonable computation times.

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SYNTHESIS AND CHARACTERIZATION OF THE POLYCATIONS FOR THE PREPAEATION OF POLYION COMPLEX MEMBRANS

  • Jegal, J.G.;park, Y.I.;Kim, J.H.;Lee, K.H.
    • 한국막학회:학술대회논문집
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    • 한국막학회 1993년도 추계 총회 및 학술발표회
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    • pp.58-58
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    • 1993
  • Pervaporation has become important as a method to separate liquid mixtures, sepecially azeotropic and close boiling-point mixtures. Especially, water-alcohol separations have been carried out a lot because of the practical interests in the industries. However, outstanding membranes with high selectivity and high permeability have not been available in common use yet. In order to separate selectively out the water mixed with alcohols with an aim of the purification of the alcohols, a membrane has tO have excellent affinity to water. Among the hydrophilic polymers, polyacrylic acid and poly(vinyl alcohol) are used widely. In recent years, ionomers and polyion complexes, better hydrophitic materials, start to be used. The polyion complex membranes, consisting of polyacrylic acid (PAA) and polycation, showed excellent permeation rates and selectivities. It was known that among the polycations, ioneries, which have quaternary ammonium groups in the backbone chain, were more effective in giving membranes of higher permselectivities. On this base, syntheses and characterizations of the polycations, with different chemical structures from the published ones, for the polyion complex membrane formation were studied in this paper.

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Stability of the Oil-in-water Type Triacylglycerol Emulsions

  • Hesson Chung;Kim, Tase-Woo;Kwon, Ich-Chan;Jeong, Seo-Young
    • Biotechnology and Bioprocess Engineering:BBE
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    • 제6권4호
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    • pp.284-288
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    • 2001
  • Lipid emulsions with saturated triacylglycerols (TAGs) with 4 to 10 carbons in each acyl chain were prepared to study how the oil component alters the stability of the lipid emul-sions when phosphatidylcholines were used as emulsifiers. The average droplet size of the emul-sions became smaller as the chain length of the TAG increased. For a given oil emulsion with smaller droplets was formed with an emulsifier having higher HLB value. The influence of HLB values on the droplet size was biggest for the tributyrin (C4) emulsion. For the tricaprylin(C8) emulsions, droplet size was identical at given emulsifier concentrations regardless of HLB values. The HLB value and the concentration of the emulsifiers also affect the droplet size of the emul-sions. The emulsions with smaller average droplet size were more stable than with bigger size for 20 days. The oil and water (o/w) interfacial tension in inversely proportional to the initial droplet size of the emulsion.

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Development of models for the prediction of electric power supply-demand and the optimal operation of power plants at iron and steel works

  • Lee, Dae-Sung;Yang, Dae-Ryook;Lee, In-Beum;Chang, Kun-Soo
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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    • pp.106-111
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    • 1992
  • In order to achieve stable and efficient use of energy at iron and steel works, a model for the prediction of supply and demand of electric power system is developed on the basis of the information on operation and particular patterns of electric power consumption. The optimal amount of electric power to be purchased and the optimal fuel allocation for the in-house electric power plants are also obtained by a mixed-integer linear programming(MILP) and a nonlinear programming (NLP) solutions, respectively. The validity and the effectiveness of the proposed model are investigated by several illustrative examples. The simulation results show the satisfactory energy saving by the optimal solution obtained through this research.

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ANALYSIS OF THREE PHASE INDUCTION MOTOR FED BY P.N.W BOXES ALGORITHM

  • Nasr, M.Sh;Abdul-baki, E.M.
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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    • pp.1035-1040
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    • 1989
  • This paper describes first Boxes algorithm as a good method to generate the pulse patterns for a pulse width modulated inverter which has a good characteristics and simple to excute. Second we present the motor analysis fed by P.W.M. inverter in steady-state operation. In this analysis we improve the MRF ( Multiple Reference Frames ) to can be easy apply to analyse all the induction motor parameters. Finally we presented all the results obtained for a 3-phase induction motor.

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RELATIONSHIP BETWEEN THE STRUCTURE OF A FACTOR RING R/P AND DERIVATIONS OF R

  • Karim Bouchannafa;Moulay Abdallah Idrissi;Lahcen Oukhtite
    • 대한수학회보
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    • 제60권5호
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    • pp.1281-1293
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    • 2023
  • The purpose of this paper is to study the relationship between the structure of a factor ring R/P and the behavior of some derivations of R. More precisely, we establish a connection between the commutativity of R/P and derivations of R satisfying specific identities involving the prime ideal P. Moreover, we provide an example to show that our results cannot be extended to semi-prime ideals.

느타리버섯 멀칭재배 방법과 수확도구 (Mulching Cultivation Method and Harvesting Implement of Pleurotus ostreatus)

    • 한국자원식물학회지
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    • 제12권3호
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    • pp.179-185
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    • 1999
  • 본 연구에서 얻어진 느타리버섯 멀칭재배의 결과를 요약하면 다음과 같다. 1) 상자재배 방법은 관행시 1695g/상자, 흑색비닐 멀칭시 24.2%가 증수된 2237g/상자, 백색비닐 멀칭시 16.4%가 증수된 2028g/상자이었다. 2) 균상재배 방법은 관행시 48.2kg/3.3m$^2$ 흑색비닐 멀칭시 57.5kg/3.3m$^2$, 백색비닐 멀칭시 52.1kg/3.3m$^2$로 각각 16.2%와 7.5%의 증수 효과가 있었다. 3) 자루재배시 느타리버섯의 발이구멍 직경은 5~30mm, 간격은 10cm일 경우 양호하였다. 4) 느타리 버섯 멀칭재배는 세균성갈변병, 푸른곰팡이, 버섯파리의 예방효과가 있었다. 5) 느타리버섯 흑색 비닐멀칭 자루재배는 균상, 상자, 봉지재배 보다 수량이 많고 품질이 좋았다. 6) 멀칭 수확도구는 45~120cm $\times$ 45~200cm 길이가 적당하였다.

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