• Title, Summary, Keyword: solution

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An Effect on the Solution Crystallization Temperature Difference and Cooling Capacity of the Absorption Chiller by a Solution Cooler in the Absorber (흡수기내 용액 냉각기가 흡수식 냉동기의 용액 결정화 온도차와 냉각 용량에 미치는 효과)

  • Chin, Sung-Min;Lee, Jae-Heon;Jurng, Jong-Soo
    • Proceedings of the KSME Conference
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    • pp.1518-1523
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    • 2003
  • The objective of the present work is to investigate an effect on the solution crystallization temperature difference and the cooling capacity of the absorption chiller by a solution cooler in the absorber. The cooling capacity of the absorption chiller can be higher, with the enhanced performance of the solution heat exchangers. But, because the solution crystallization temperature difference becomes smaller at the absorber inlet, the heat capacity of the solution heat exchangers might be limited by the danger of crystallization, which can cause the serious damages. In this paper, the heat capacity ratio of the solution cooler is defined as the ratio of the heat capacity of the solution cooler to that of the absorber. If it becomes larger in the additional type solution cooler, the solution crystallization temperature difference is augmented and the cooling capacity is also increased.

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The Effect of Antiseptic and Sugar Solution on Colony Development of the Bumblebees, Bombus ignitus and B. terrestris

  • Yoon Hyung Joo;Kim Sam Eun;Lee Sang Beom;Seol Kwang Youl
    • International Journal of Industrial Entomology
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    • v.11 no.1
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    • pp.43-48
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    • 2005
  • We investigated possible effect of different concentration of sugar solution and addition of antiseptic in the solution on oviposition and colony development of Bombus ignitus and B. terrestris. The rates of oviposition, colony foundation and progeny-queen production of B. ignitus were 1.2-3.0 fold higher in the 40$\%$ sugar solution than those of the 50$\%$ sugar solution. The rates of oviposition, colony foundation and progeny­queen production were 1.1-2.6 fold higher in the 40$\%$ sugar solution added in 0.3$\%$ sorbic acid as antiseptic than those of the 40$\%$ sugar solution. Further, the death rate within one month was 1.7 fold lower in the 40$\%$ sugar solution added in 0.3$\%$ sorbic acid than that of 40$\%$ sugar solution alone. In the comparison of the colony development tested using imported sugar solution, the Beehappy???, the 40$\%$ sugar solution added to antiseptic and the 40$\%$ sugar solution with­out antiseptic, the 40$\%$ sugar solution added to antiseptic was about equal to the Beehappy??? in colony development of B. terrestris. Further, the number of adults produced was 1.2-3.0 fold higher in the 40$\%$ sugar solution added to antiseptic than that of the Bee­happy???. Therefore the 40$\%$ sugar solution was more effective than the 50$\%$ sugar solution, and the 40$\%$ sugar solution added to antiseptic was the most effective in colony development and mass rearing of bumblebee.

Storage stability of silk solution for viscosity and electrospinnability

  • Kim, Su Jin;Um, In Chul
    • International Journal of Industrial Entomology
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    • v.33 no.2
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    • pp.138-143
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    • 2016
  • In the present study, silk fibroin (SF) was dissolved in $CaCl_2/H_2O/EtOH$ solution at $85^{\circ}C$. After the dissolution, the SF solution was cooled down and stored at $4^{\circ}C$ for 28 d. The stability of the solution's viscosity and electrospinnability was observed to examine the stability of SF molecules during storage in $CaCl_2/H_2O/EtOH$ solution. The viscosities of $SF/CaCl_2/H_2O/EtOH$ solution and SF formic acid solution did not change during 28 days' storage of SF in $CaCl_2/H_2O/EtOH$ solution. The electrospinnability of the SF solution, mean diameter of the electrospun SF fiber, and crystallinity index of electrospun SF web did not change, regardless of the length of the storage period. These results imply that SF molecules do not degrade during 28 days' storage in $CaCl_2/H_2O/EtOH$ solution.

A Validation Method for Solution of Nonlinear Differential Equations: Construction of Exact Solutions Neighboring Approximate Solutions

  • Lee, Sang-Chul
    • International Journal of Aeronautical and Space Sciences
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    • v.3 no.2
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    • pp.46-58
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    • 2002
  • An inverse method is introduced to construct benchmark problems for the numerical solution of initial value problems. Benchmark problems constructed through this method have a known exact solution, even though analytical solutions are generally not obtainable. The solution is constructed such that it lies near a given approximate numerical solution, and therefore the special case solution can be generated in a versatile and physically meaningful fashion and can serve as a benchmark problem to validate approximate solution methods. A smooth interpolation of the approximate solution is forced to exactly satisfy the differential equation by analytically deriving a small forcing function to absorb all of the errors in the interpolated approximate solution. A multi-variable orthogonal function expansion method and computer symbol manipulation are successfully used for this process. Using this special case exact solution, it is possible to directly investigate the relationship between global errors of a candidate numerical solution process and the associated tuning parameters for a given code and a given problem. Under the assumption that the original differential equation is well-posed with respect to the small perturbations, we thereby obtain valuable information about the optimal choice of the tuning parameters and the achievable accuracy of the numerical solution. Illustrative examples show the utility of this method not only for the ordinary differential equations (ODEs) but for the partial differential equations (PDEs).

유선 시뮬레이션 기법과 준해석해를 이용한 용질 거동 분석

  • 정대인;최종근;박광원
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • pp.57-62
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    • 2004
  • Streamline simulation researches have been extensively accomplished due to the swiftness of computation and the reduction of numerical dispersion. In this study, we developed a streamline simulation model using a semianalytical solution of ID transport equation. To validate accuracy of the developed model, we compared simulation results of contaminant transport, which were acquired by streamline simulation models using an analytical solution, a numerical solution, and a semianalytical solution. The developed model using the semianalytical solution matched well with the model using an analytical solution. However, streamline simulation model using a numerical solution showed numerical dispersion. For an advection-dominant flow, there was little difference in the simulation results between the developed model and tile analytical model, but the differences between the analytical model and the numerical model were cleary shown. From the comparison of computing time we know that the streamline simulation using the semianalytical solution is 2-60 times as fast as the streamline simulation using the numerical solution.

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Fully Solution-Processed Green Organic Light-Emitting Diodes Using the Optimized Electron Transport Layers (최적화된 전자 수송층을 활용한 완전한 용액공정 기반 녹색 유기발광다이오드)

  • Han, Joo Won;Kim, Yong Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.31 no.7
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    • pp.486-489
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    • 2018
  • Solution-processed organic light-emitting diodes (OLEDs) have the advantages of low cost, fast fabrication, and large-area devices. However, most studies on solution-processed OLEDs have mainly focused on solution-processable hole transporting materials or emissive materials. Here, we report fully solution-processed green OLEDs including hole/electron transport layers and emissive layers. The electrical and optical properties of OLEDs based on solution-processed TPBi (2,2',2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)) as the electron transport layer were investigated with respect to the spin speed and the number of layers. The performance of OLEDs with solution-processed TPBi exhibits a power efficiency of 9.4 lm/W. We believe that the solution-processed electron transport layers can contribute to the development of efficient fully solution-processed multilayered OLEDs.

The effect of electrolytes on the preparation of an extraction replica in 3 wt. % Si steel (3% Si 강의 추출복제시료제조에 미치는 전해액의 영향)

  • Park, Shin-Hwa;Kim, Jae-Kwan;Kim, Jae-Nam;An, Byung-Ryang;Lee, Do-Hyung
    • Applied Microscopy
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    • v.23 no.2
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    • pp.1-10
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    • 1993
  • The effect of electrolyte on the extraction replicas of the precipiates in 3% Si steel was investigated. Three Kinds of electrolyte, 2% Nital solution (2% nitric acid+methanol; acid solution),, Sodium Citrate solution (5% sodiumcitrate+1% KBr+0.5KI+$H_{2}O$; aqueous neutral solution) and 10% AA solution (10% acetylacetone+ 1% tetramethylammoniumchloride+methanol; non-aqueous neutral solution), were compared. The preciptiates in 3% Si steel were dissolved in 2% Nital, but they were not dissolved in the Sodium Citrate and 10% AA solution. In Sodium Citrate solution, however, large second artifacts were introduced during sample preparation. Therefore 10% AA solution was found to be most useful for the preparation of extraction replica. The electrolysis condition of a matrix and precipitates were also checked by the measurement of potential-current curve in 10% AA solution. The matrix was electrolyzed at -400mV with respect to SCE(Saturated Calomel Electrode). In contrats precipitates were electrolyzed above 300mV. Precipitates were respected to be stable in 10% AA solution in the range of $-380mV{\sim}-300mV$ usually used to prepare extraction replicas.

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Development of Nutrient Solution Control System for Water Culture (수경재배(水耕栽培)의 양액관리(養液管理) 자동화(自動化) 시스템 개발(開發))

  • Lee, K.M.;Lee, J.S.;Sun, C.H.;Jang, I.J.;Song, J.G.;Koo, G.H.
    • Journal of Biosystems Engineering
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    • v.15 no.4
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    • pp.328-338
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    • 1990
  • The objective of this study was to develop automatic systems of nutrient solution management for optimal nutrient solution environment and labor saving in water culture which enables factory crop production. In this study, an automatic control system and its driving program are developed to prepare, supply, and recover nutrient solution and to keep the optimal solution concentration level using microcomputers. Based on this study, the following conclusions are obtained: 1. The concentration measured by the system using oscillating circuit designed and built in this study, gave good agreements with the actual nutrient solution. 2. In water culture, the period of 12 hours for measuring concentration, pH, and temperature of the nutrient solution was optimum. Addition of control solution due to the decrease of the nutrient solution concentration is required in every 3 to 5 days. 3. It is estimated that the period of the whole solution change is 15 days, however, further research is needed to assure it. In addition, this period must be shortened in the future. 4. Both the hardware and software of the developed optimal nutrient solution control system in the water culture are working very well, however, it is necessary to develop a more economical one-chip micro controller to substitute for the microcomputer.

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A Study on the Error Analysis of the Numerical Solution using Inverse Method (역해석 기법을 이용한 수치해의 오차 분석 연구)

  • Yang, Sung-Wook;Lee, Sang-Chul
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.16 no.2
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    • pp.21-27
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    • 2008
  • An inverse method is introduced to construct the problem for the error analysis of the numerical solution of initial value problem. These problems constructed through this method have a known exact solution, even though analytical solutions are generally not obtainable. The process leading to the exact solution makes use of an initially available approximate numerical solution. A smooth interpolation of the approximate solution is forced to exactly satisfy the differential equation by analytically deriving a small forcing function to absorb all of the errors in the interpolated approximate solution. Using this special case exact solution, it is possible to investigate the relationship between global errors of a candidate numerical solution process and the associated tuning parameters for a given problem. Under the assumption that the original differential equation is well-posed with respect to the small perturbations, we thereby obtain valuable information about the optimal choice of the tuning parameters and the achievable accuracy of the numerical solution.

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