• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.1
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• pp.178-184
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• 2007

In the present work, the vermicomposting index was investigated using leakage water from sludge to develop the process of mechanization and automation in the earthworm-cast treatment. The in situ sewage sludge was used batch and continuous experiments. Due to different treatment processes, the physico-chemical characteristics of liquid extracted from sludge was the similar change pattern. However, some items, such as Oxidation Reduction Potential (ORP), pH, Electrical Conductivity (EC) and $NH_3-N$, showed the distinct changes between pre- and post-vermicomposting. Also, The ORP and EC were the best parameters for the vermicomposting index. These results offered that the present vermicomposting technology was an actual earthworm-cast treatment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.10
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• pp.12-19
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• 2004

An aerodynamic design optimization system for three-dimensional wing was developed as a part of the future MDO framework. The present design optimization system includes four modules such as geometry design, grid generation, flow solver and optimizer. All modules were based on commercial softwares and programmed to have automated execution capability in batch mode utilizing built-in script and journaling. The integration of all modules into the system was accomplished through programming using Visual Basic language. The distributed computational environment based on network communication was established to save computational time especially for time-consuming aerodynamic analyses. The distributed aerodynamic computations were performed in conjunction with the global optimization algorithm of response surface method, instead of using usual parallel computation based on domain decomposition. The application of the design system in the drag minimization problem demonstrated considerably enhanced efficiency of the design process while the final design showed reasonable results of reduced drag.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.9
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• pp.775-782
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• 2009

PP-g-AA-Am nonwoven fabric, which possess anionic exchangeable function, was prepared by chemical modification of carboxyl (-COOH) group of PP-g-AA nonwoven fabric to amine ($-NH_2$) group using diethylene triamine (DETA). Its adsorption characteristics for anionic nutrients including isotherm, kinetics and co-anions were studied by batch adsorption experiments. Adsorption equilibriums of $PO_4$-P on PP-g-AA-Am fabric were well described by the Langmuir isotherm model, and their adsorption energies were ranged 10.3 kJ/mol indicating an ion-exchange process as primary adsorption mechanism. The adsorption selectivity of PP-g-AA-Am nonwoven fabric for anions under competition with each other was in following order: $SO_4\;^{2-}$>$PO_4\;^{3-}$>$NO_3\;^-$>$NO_2\;^-$. Also, all results obtained from this study indicate that the $PO_4$-P removal capacity of PP-g-AA-Am nonwoven fabric was extremely superior to that of PA308 anion-exchange resin.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.422-427
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• 2003

Rhodopseudomonas palustris P4 can produce $H_2$ either from CO by water-gas shift reaction or from various sugars by anaerobic fermentation. Fermentative $H_2$ production by P4 is fast, but its yield is relatively low due to the formation of various organic acids. In order to increase $H_2$ production yield from glucose, P4 was investigated for the photo-fermentation of acetate which is a major by-product of fermentative $H_2$ production. Experiments were performed in batch modes using both light-grown and dark-grown cells. When the dark-grown P4 was challenged with light and acetate, $H_2$ was produced with the consumption of acetate after a lag period of 25 h. $H_2$ production was inhibited when a nitrogen source, especially ammonium, is present. When the dark-fermentation broth containing acetate was adopted for photo-fermentation with light-grown cells, $H_2$ production and concomitant acetate consumption occurred without a lag period. The $H_2$ yield was estimated as 2.4 - 2.8 mol $H_2/mol$ acetate and the specific $H_2$ production rate was as 9.8 ml $H_2/g$ cell${\cdot}$h, The fact that a single strain can perform both dark- and light-fermentation gives a great advantage in process development Compared to a one-step dark-fermentation, the combined dark- and light-fermentation can increase the $H_2$ production yield on glucose by two-fold.

• KSBB Journal
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• v.7 no.2
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• pp.132-138
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• 1992

Sprial adaptation technique of conditioned media has been applied to cultivate human cell line which can not survive in a serum free mdium without adding any growth factors in basal medium Doubling time and scu-PA production from serum free adapted cells were 5 days and 890 (IU/mL), respectively in a T-flask, whose values were not much lower than the productivity of 1100(IU/mL) from 5% serum containing medium. It was required to use conditioned media for attaching cells on microcarriers when cells were inoculated into a spinner vessel. Then, cells could continuously grow in serum free medium with having specific growth rate of 0.106 (1/day) and specific scu-PA production rate of $1.58{\times}10_{-5}$(IU/cell/day) in batch cultivation.

• KSBB Journal
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• v.7 no.2
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• pp.139-143
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• 1992

One of the objectives of this work is to obtain information relevant to the industrial production of alcohol from sugar. The fermentation of alcohol by a strain of saccharomycess cerevisiae ATCC 24858 was studied In a continuous single-stage process with recycle of the cells via tangential flow microfiltration membranes. The experimental results reported in this study pertain to continuous cultures with total cell-recycle by varying the dilution rate (D=0.3, 0.5, and 0.7 $hr^{-1}$) and glucose concentration (50, 100, 150, and 200g/l sugar solution). Productivity using a repeated cell recycle system was found extremely high, 1.e., over 10 to 29 times higher than that of a smile batch system. When a sugar concentration of 200g/1 at dilution rate, 0.7 hr-1 was used, 83.9g/l ethanol was formed with an ethanol yield of 0.42(82% of theoretical) based on sugars utilized.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.4
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• pp.201-206
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• 2013

The coal bottom ash and reject ash discharged from a coal-fired power plant are difficult to recycle so most of them are mainly landfill-disposed. In this study, the artificial aggregate were produced using reject ash, bottom ash and dredged soil emitted from the coal-fired power plant in Korea and the effect of experimental factors on the bloating behavior and the properties of the aggregates were analyzed. In particular, a lot of unburned carbon in the reject ash was removed by calcination and the activated carbon was added to batch powders then the dependence of those process upon bloating properties of artificial aggregate were investigated. For this purpose, the specific gravity and water absorption values of artificial aggregates were investigated in conjunction with microstructural observations. This study could contribute to increase the recycling rate of the reject ash.

• Journal of Environmental Science International
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• v.26 no.6
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• pp.719-728
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• 2017

In order to investigate the adsorption characteristics for Sr ion using the Na-X zeolite synthesized from coal fly ash, batch tests and response surface analyses were carried out. The adsorption kinetic data for Sr ions, using Na-X zeolite, fitted well with the pseudo-second-order model. The uptake of Sr ions followed the Langmuir isotherm model, with a maximum adsorption capacity of 196.46 mg/g. Thermodynamic studies were conducted at different reaction temperatures, with the results indicating that Sr ion adsorption by Na-X zeolite was an endothermic (${\Delta}H^o$>0) and spontaneous (${\Delta}G^o$<0) process. Using the response surface methodology of the Box-Behnken method, initial Sr ion concentration ($X_1$), initial temperature ($X_2$), and initial pH ($X_3$) were selected as the independent variables, while the adsorption of Sr ions by Na-X zeolite was selected as the dependent variable. The experimental data fitted well with a second-order polynomial equation by multiple regression analysis. The value of the determination coefficient ($R^2=0.9937$) and the adjusted determination coefficient (adjusted $R^2=0.9823$) was close to 1, indicating high significance of the model. Statistical results showed the order of Sr removal based on experimental factors to be initial pH > initial concentration > temperature.

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.819-825
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• 2014

In this paper, monaural ambient component extraction algorithm based on nonnegative matrix factorization (NMF) is described. The ambience component extraction algorithm in this paper is developed for audio upmixing system; Recent researches have shown that they can enhance listener envelopment if the extracted ambient signal is applied into the multichannel audio upmixing system. However, the conventional method stores all of the audio signal and processes all at once, so it cannot be applied to streaming system and digital signal processor (DSP) system. In this paper, the ambient component extraction algorithm based on on-line nonnegative matrix factorization is developed and evaluated to solve the problem. As a result of analysis of the processed signal with spectral flatness measures in the experiment, it was shown that the developed system can extract the ambient signal similarly with the conventional batch process system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.840-843
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• 2002

The dry pulverizing/Mixing device is used to deal with the spent fuels for the safe disposal. The separated pellets from hulls by a slitting device are put and oxidized from UO$_2$ solid pellet to U$_3$O$\_$8/ powder in the device. The device have been developed based on a voloxidation method which is one of several dry de-cladding methods. We have benchmarked dry de-cladding methods, analyzed applicability to the advanced spent fuel management process, integrated and compared several configuration, and finally derived detailed specifications proper to requirements for the device. Also, thermal characteristics of the device such as thermal stress and strain have been analyzed by the commercial software, 1-DEAS, and the reliability of the results have been verified by the KOLAS(Korea Laboratory Accreditation Scheme). The UO$_2$ solid pellets are put in the device which has a capacity of 20 kgHM per a batch, heated up about 600$^{\circ}C$ in the air environment. Then, the UO$_2$ solid pellets are oxidized into the U$_3$O$\_$8/ powder, and the powder is collected in a special vessel. The device has been designed and developed as fellows: the multi-staged fine hole meshes are used to reduce the size of the powder gradually, heat and air(oxygen) are supplied continuously to reduce the reaction time, and slight vibration effect are applied to collect powder cling to the device.