• Title/Summary/Keyword: Dilution

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Development of Soil Dilution Planting Method for Ecological Studies of Pythium Populations (Pythium Population 의 생태적 특성 고찰을 위한 Soil Dilution Planting Method의 개발)

  • Lee, Youn-Su
    • Korean Journal of Environmental Agriculture
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    • v.13 no.1
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    • pp.83-89
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    • 1994
  • The number of colonies often decreased more than would be expected in a dilution from 1:50 to 1:100; however, a lack of agreement between the dilution series and the number of colonies obtained also occurred at higher dilutions. In the experiments with each soil subsample, there was sometimes poor agreement between the number of colonies obtained at the same dilution from the A and B subsamples. However, repeated 1:50 dilutions of soil suspensions of subsamples A and B yielded similar numbers of colonies. In the second experiment series conducted with a second composite soil sample, the number of colonies obtained from each soil subsample decreased following air drying. The results suggest that it was difficult to obtain a uniform distribution of Pythium propagules in the two sugarcane field soils tested. The high number of propagules detected at the 1:50 dilution could have been due to hyphal fragments or connected hyphal swellings that separated during the final mixing or during plating.

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Effect of Intake Flow Control Method on Part Load Performance in SI Engine(2) - EGR Characteristics and Comparison of Dilution Method (스파크점화기관에서 흡기제어 방식이 부분부하 성능에 미치는 영향(2) - EGR 특성과 희석 방법의 비교)

  • Kang, Min Gyun;Ohm, Inyong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.4
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    • pp.121-130
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    • 2014
  • This paper is the second investigation on the effects of intake flow control methods on the part load performance in a spark ignition engine. In the previous work, two control methods, port throttling and masking, were compared with respect to lean misfire limit, fuel consumption and emissions. In this work, the effects of these two methods on EGR characteristics were studied and simultaneously the differences between EGR and lean combustion as a dilution method were investigated. The results show that EGR limit is expanded up to 23% and 3 ~ 5% improvement in the fuel consumption are achieved around 8 ~ 13% rates by the flow controls comparing with 10% limit and 1.5% reduction around 3% rate of non-control case. The masking method is more effective on the limit expansion than throttling as like as lean misfire limit; however there is no substantial difference in fuel consumptions improvement regardless the control methods except high load condition. Also it is observed that there exist critical EGR rates around which the combustion performance and NOx formation change remarkably and these rates generally coincide with optimum rates for the fuel consumption. In addition, dilution with fresh air is much more advantageous than that of the exhaust gas from the view point of dilution limit and fuel consumption, while utilization of the exhaust gas is more effective on NOx reduction in spite of considerably small dilution compared with the use of fresh air. Finally, the improvement of fuel consumption by massive EGR is highly dependent on the EGR limit at which the engine runs stably, therefore the stratified combustion technique might be a best solution for this purpose.

Mass Production of Mammalian Cells under Chemostat Cultivation (동물세포의 연속 대량생산에 관한 연구)

  • 이현용;강재구;박형환
    • Microbiology and Biotechnology Letters
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    • v.17 no.3
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    • pp.173-177
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    • 1989
  • Cell density was gradually decreased as the dilution rate was increased under chemostat cultivation of HeLa cells. Maxium cell density was maintained at the dilution rate of 0.020 (1/h) which was far less than the wash-out rate of 0.050 (1/h), Maxium cell productivity of 2 (mL of cells/L/h)was obtained at the dilution rate of 0.030 (1/h) by showing the culture also required maintenance period at low dilution rates, whose result meant the deviation of continuous culture theroy. Methods of indirectly measuring cell density have been introduced to represent mammalian cell growth, which are packed cell volume and oxygen uptake rate, and these values showed good linear relationship with actual cell density by having correlation factor of 0.90. Theoretical maximum oxygen yield, $Y_{O2}^{max}$ and maintenance oxygen consumption rate, m$_{O2}$, were estimated as 4.1$\times$10$^5$ (cells/mmole $O_2$) and 10.71$\times$10$^{-9}$ (mmole $O_2$/cells/h) by employing oxygen yield model.

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A Case Study of Prediction and Analysis of Unplanned Dilution in an Underground Stoping Mine using Artificial Neural Network (인공신경망을 이용한 지하채광 확정선외 혼입 예측과 분석 사례연구)

  • Jang, Hyongdoo;Yang, Hyung-Sik
    • Tunnel and Underground Space
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    • v.24 no.4
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    • pp.282-288
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    • 2014
  • Stoping method has been acknowledged as one of the typical metalliferous underground mining methods. Notwithstanding with the popularity of the method, the majority of stoping mines are suffering from excessive unplanned dilution which often becomes as the main cause of mine closure. Thus a reliable unplanned dilution management system is imperatively needed. In this study, reliable unplanned dilution prediction system is introduced by adopting artificial neural network (ANN) based on data investigated from one underground stoping mine in Western Australia. In addition, contributions of input parameters were analysed by connection weight algorithm (CWA). To validate the reliability of the proposed ANN, correlation coefficient (R) was calculated in the training and test stage which shown relatively high correlation of 0.9641 in training and 0.7933 in test stage. As results of CWA application, BHL (Length of blast hole) and SFJ (Safety factor of Joint orientation) show comparatively high contribution of 18.78% and 19.77% which imply that these are somewhat critical influential parameter of unplanned dilution.

A Bio-fluidic Device for Adaptive Sample Pretreatment and Its Application to Measurements of Escherichia coli Concentrations

  • Choi Won-Jae;Park Je-Kyun
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.11 no.1
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    • pp.54-60
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    • 2006
  • In this paper, we describe a bio-fluidic device for adaptive sample pretreatment, in order to optimize the conditions under which absorbance assays can be conducted. This device can be successfully applied to the measurement of Escherichia coli (E. coli) concentrations using adaptive dilution, with which the dilution ratio can be adjusted during the dilution. Although many attempts have been previously made to miniaturize complex biochemical analyses at the chip scale, very few sample pretreatment processes have actually been miniaturized or automated at this point. Due to the lack of currently available on-chip pretreatments, analytical instruments tend to suffer from a limited range of analysis. This occasionally hinders the direct and quantitative analysis of specific analyses obtained from real samples. In order to overcome these issues, we exploit two novel strategies: dilution with a programmable ratio, and to-and-fro mixing. The bio-fluidic device consists of a rectangular chamber constructed of poly(dimethylsiloxane) (PDMS). This chamber has four openings, an inlet, an outlet, an air control, and an air vent. Each of the dilution cycles is comprised of four steps: detection, liquid drain, buffer injection, and to-and-fro mixing. When using adaptive sample pretreatment, the range in which E. coli concentrations can be measured is broadened, to an optical density (O.D.) range of $0.3{\sim}30$. This device may prove useful in the on-line monitoring of cell concentrations, in both fermenter and aqueous environments.

A Study on Initial and Near-Field Dilution at the Ocean Outfall of Masan-Changwon Municipal Wastewater Treatment Plant (마산ㆍ창원 하수종말 처리장의 해양방류 처리수에 대한 초기ㆍ근역 희석연구(I))

  • Kang See-Whan;You Sung-Hyup;Oh Byung-Cheol
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.2 no.2
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    • pp.60-69
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    • 1999
  • In this paper, we have obtained the initial and near-field dilution rates of wastewaters discharged from the ocean outfall of Masan-Changwon municipal wastewater treatment plant from both of field measurements and CORMIX model simulations. In the summer of 1998, water temperature and salinity profiles was measured at 16 stations in the vicinity of the Masan outfall and the dilution rates were analyzed by salinity deficit method. The transport of the wastefields and their initial dilution rates were calculated by CORMIX model using field data as model input. Both of observed and predicted results are shown In very low dilutions with the range of 32~48 from the field data analysis and 29~43 from the model prediction, respectively. This indicates that the water quality in the Masan outfall area can be worsening due to the low dilution rates of diswastewaters, especially, when the ambient currents are very weak in a neap tide and ambient water density is highly stratified in summer.

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Assessment of Electrical Conductivity of Saturated Soil Paste from 1:5 Soil-Water Extracts for Reclaimed Tideland Soils in South-Western Coastal Area of Korea

  • Park, Hyun-Jin;Yang, Hye In;Park, Se-In;Seo, Bo-Seong;Lee, Dong-Hwan;Kim, Han-Yong;Choi, Woo-Jung
    • Korean Journal of Environmental Agriculture
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    • v.38 no.2
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    • pp.69-75
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    • 2019
  • BACKGROUND: Measurement of electrical conductivity of saturated soil paste ($EC_e$) for assessment of soil salinity is time-consuming, and thus conversion of EC of 1:5 soil-water extract ($EC_{1:5}$) to $EC_e$ using a dilution factor may be of help to monitor salinity of huge number of soil samples. This study was conducted to evaluate the dilution factor for reclaimed tideland (RTL) soils of South Korea. METHODS AND RESULTS: Soil samples (n=40) were collected from four RTLs, and analyzed for $EC_{1:5}$, $EC_e$, and cation compositions of 1:5 soil-water extract. The dilution factor (8.70) was estimated by regression analysis between $EC_{1:5}$ and $EC_e$, and the obtained dilution factor was validated by applying to an independent data set (n=96) of $EC_{1:5}$ and $EC_e$. The $EC_e$ measured and predicted was strongly correlated ($r^2=0.74$, P<0.001), but $EC_e$ was overestimated by 16% particularly for the soils with high clay content and low sodium adsorption ratio (SAR). CONCLUSION: This study suggests that using the dilution factor to convert $EC_{1:5}$ to $EC_e$ is feasible method to monitor changes in the soil salinity of the study RTL. However, overestimation of $EC_e$ should be cautioned for the soils with high clay content and low SAR.

Spectral CT Analysis of Hounsfield Unit (HU) according to MonoE (keV) and Dilution Ratio of the Contrast Agent: Use of Spectral CT (단색에너지(keV)와 조영제 희석비율 변화에 따른 HU(Hounsfield Unit)값 분석: Spectral CT 이용)

  • Jung, Hee-Ra;Kang, Jin-woo;Kwon, Oh-Jun;Kim, Ho-Jin;Jung, Dabin;Lee, Jae-Hyun;Heo, Yeong-Cheol
    • Journal of the Korean Society of Radiology
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    • v.14 no.5
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    • pp.669-676
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    • 2020
  • The purpose of this study was to analyze the changes in the values of Hounsfield Unit (HU) according to the changes in monoenergy (keV) and dilution ratio of the contrast agent, using the spectral CT. Spectral CT was used as the testing device, while 20 cc syringe phantom was used to set a total of six dilution ratios of the contrast agent: 8:2, 7:3, 6:4, 5:5, 4:6, and 3:7. Here, the non-ionic iodine solution (350 mg/ml) was used as a contrast agent. The syringe axial image was reconstructed by adjusting the obtained data on nine MonoE levels; 40 keV, 45 keV, 50 keV, 55 keV, 60 keV, 65 keV, 70 keV, 75 keV, and 80 keV. The HU values were measured at the three points of the reconstructed syringe axial image. The measurements were taken 1,620 times in total. In the analysis of the HU values according to the changes in keV and dilution ratio of the contrast agent, the highest and lowest HU values were obtained from dilution ratio 8:2 and dilution ratio 3:7, respectively, across every MonoE in the comparison of HU according to dilution ratio per MonoE (p<0.05), while the highest and lowest HU values were obtained from 40 keV and 80 keV, respectively, across all dilution ratios in the comparison of HU according to MonoE per dilution ratio (p<0.05). For the correlation per each parameter, a negative correlation of -15.014 ± 0.298 was found for HU per keV (R2=0.519) and a negative correlation of -61.372 ± 3.608 was found for HU per dilution ratio (R2=0.152) (p<0.05). To conclude, an increase in keV or dilution ratio of the contrast agent was shown to decrease the HU, and the findings in this study are anticipated to serve as the basic data in the research of HU-related parameters in Spectral CT.

A Effect on the Maintenance of Chicken Freshness through $\pi$-Water Treatment ($\pi$-Water 처리를 통한 닭고기의 신선도 유지 효과)

  • 김윤태
    • Culinary science and hospitality research
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    • v.8 no.2
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    • pp.197-206
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    • 2002
  • The present study attempted to obtain a basic data concerning the effect of $\pi$-water, a sort of physiological water, on the maintenance of chicken freshness. The meats were divided into three groups: the control, 20% - dilution, and 5% - dilution groups. In the experiment, the changes of the TBA-values of the meats started to appear on the 3rd day in the control group, and from the 4th day in the 20% - and 5% - dilution groups. The changes of pH didn't appear in the meats as the storage time passed. The number of general bacteria increased rapidly on the 3th day in the control, and on the 5th day in the 20% -, and 5% - dilution groups. As for the color, the meats turned greenish on the 5th day in the control, 7th, in 20% - dilution, and, l0th in the 5%-dilution groups. As for the order, the meats emitted the unpleasant order, such as that of ammonia, on the 3rd day in the control, 5th, in the 20% - dilution, and, 7th, in the 5ft-dilution group.

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