• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.6
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• pp.305-311
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• 2012

In order to recycle the coal bottom ashes (denoted as BA) produced from a thermal power plant, the artificial aggregates (denoted as AAs) containing BA and red clay were manufactured, and the physical properties of AAs were studied as a function of particle size of BA and batch compositions. As-received BA had 38 wt% coarse particles of above 2 mm and many unburned carbon mass and porous slag particles were co-existed. So the two particle sizes of BA, the fine (< 100 ${\mu}m$) and coarse (< 2 mm), were prepared by milling and screening process. The AAs containing fine BA sintered at $1100{\sim}1200^{\circ}C$ had the higher bulk density and lower water absorption compared to the specimen made of coarse BA. The inside core of AAs manufactured by using coarse BA showed nonuniform and porous microstructure, while the AAs made of fine BA had a uniform and dense microstructure. In this research, the AAs containing BA and red clay with various bulk density (1.2~1.7) and water absorption (13~21 %) could be manufactured by controlling the particle size of BA and batch compositions, so the AAs of various physical properties could be applied to the wide fields such as construction/building materials in near future.

• Clean Technology
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• v.20 no.2
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• pp.103-107
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• 2014

Acrylic acid is a commodity chemical which is applicable for various industries such as polymer and textile industry. Currently, it has been produced by chemical synthesis from petroleum. However, due to the high price of petroleum and global $CO_2$ emission, renewable materials such as sugar are interesting alternative carbon sources for the biological production of acrylic acid. For an economic production of acrylic acid from renewable carbon sources, a cost effective separation process for acrylic acid should be needed. In this study, reactive extraction by TOA (tri-n-octylamine) was used for the recovery of acrylic acid from its aqueous solutions. The effects of polarity of diluents and concentration of TOA on extraction equilibrium were investigated. The extraction efficiency was proportional to concentration of TOA and polarity of diluents and its value was more than 95% in the case of sufficient concentration of TOA. From IR spectroscopy, it was concluded that the ratio of (1,1) acid-amine complex was increased and the ratio of acid dimer was decreased with concentration of TOA. Equilibrium model based on IR spectroscopy was well fitted with experimental data.

• Korean Journal of Food Science and Technology
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• v.37 no.5
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• pp.850-855
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• 2005

Model was developed to predict the growth of Listeria monocytogenes in raw pork. Experiment condition for model development was full 5-by-7 factorial arrangements of temperature (0, 5, 10, 15, and $20^{\circ}C$) and time (0, 1, 2, 3, 18, 48, and 120 hr). Gompertz values A, C, B, and M, and growth kinetics, exponential growth rate (EGR), generation time (GT), lag phase duration (LPD), and maximum population density (MPD) were calculated based on growth increased data. GT and LPD values gradually decreased, whereas EGR value gradually increased with increasing temperature. Response surface analysis (RSA) was carried out using Gompertz B and M values, to formulate equation with temperature being main control factor. This equation was applied to Gompertz equation. Experimental and predictive values for GT, LPD, and EGR, compared using the model, showed no significant differences (p<0.01). Proposed model could be used to predict growth of microorganisms for exposure assessment of MRA, thereby allowing more informed decision-making on potential regulatory actions of microorganisms in raw pork.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.112-118
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• 2018

Adsorption equilibrium, kinetic and thermodynamic parameters of a brilliant green from aqueous solutions at various initial dye concentration (10~30 mg/L), contact time (1~24 h) and temperature (298~318 K) on zeolite were studied in a batch mode operation. The equilibrium adsorption values were analyzed by Langmuir, Freundlich and Dubinin-Radushkevich model. The results indicate that Langmuir and Freundlich model provides the best correlation of the experimental data. Base on the estimated values of Langmuir dimensionless separation factor ($R_L=0.041{\sim}0.057$) and Freundlich constant (1/n=0.30~0.47), this process could be employed as effective treatment method. calculated values of adsorption energy by Dubinin-Radushkevich model were 1.564~1.857 kJ/mol corresponding to physical adsorption. The adsorption kinetics of brilliant green were best described by the pseudo second-order rate model and followed by intraparticle diffusion model. Thermodynamic parameters such as activation energy, free energy, enthalpy and entropy were calculated to estimate nature of adsorption. negative Gibbs free energy (-10.3~-11.4 kJ/mol), positive enthalpy change (49.48 kJ/mol) and Arrehenius activation energy (27.05 kJ/mol) indicates that the adsorption is spontaneous, endothermic and physical adsorption process, respectively.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.3
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• pp.193-198
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• 2013

In general, boron recovery of 40-90% could be achieved by Reverse Osmosis (RO) membranes in neutral pH condition. As an emerging technology, Forward Osmosis (FO) membrane has attracted growing interest in wastewater treatment and desalination. The objective of this study is to evaluate the possibility of the boron removal in radioactive liquid waste by FO. In this study, the performance of FO was investigated to remove boron in the simulated liquid waste as the factors such as pH, osmotic pressure, ionic strength of solution, etc. The pH of feed solution is a major operating parameter which strongly influences to the permeation of boron and more than 80% of boron content can be separated when conducted at pH values less than 7. The water flux is not influenced but the boron flux and permeation rate tends to decrease in the low salt concentration of 1,000 mg/L. The boron flux increases linearly, but the permeation ratio of reducing boron is nearly constant even with changes in the draw solution concentration.

• The KIPS Transactions:PartD
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• v.12D no.5 s.101
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• pp.797-806
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• 2005

The objective of the In-h(High Level Architecture) have recommended by DoD(Department of Defense) is to facilitate interoperability among simulations and to promote reuse of their components. There are many legacy simulation softwares developed before the HLA becomes simulation standard. The integration of legacy simulations into federations using the HLA is an important research topic in M&S(Modeling and Simulation) area. Legacy simulation softwares of the mission critical industry such as nuclear and aerospace are generally use Fortran language. However, the reuse of those is not easy because the HLA is not support Fortran language. This paper suggests a integration method which minimizes the modification of legacy simulation software and migrates the legacy simulation software to HLA federation. Each federate participating in federation have the separated executables that communicate via a shared memory created at run-time. Two types of shared memory blocks are used for publication and subscription. Declaration block for global variables used in legacy simulation software is separated for publication and subscription and then mapped as classes of objects and interactions for the HLA FOM design. To validate the suggested method, we approached the HLA integration of legacy nuclear simulation code being used in plant design and to observe the integration results, we used the FMT(Federation Management Tool). The diagnostic information which the FTM displays showed that our method can be successfully and effectively used for a HLA federation.

• Resources Recycling
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• v.7 no.3
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• pp.3-10
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• 1998

Simulated waste liquid containing 50 ppm cobalt ion was treated by adsorbing colloidal flotation using Fe(III) or Al(IlI) as flocclant and a sodium lamyl sulfate as a collector. Parameters such as pH, surfactant concentration, Fe(III) or Al(III) concentration, gas flow rate, etc., W앙e considered. The flotation with Fe(III) showed 99.8% removal efficiency of cohalt on the conditions of initial cobalt ion concentration 50 ppm, pH 9.5, gas flow rate 70 ml/min, and flotation time 30 min. When the waste solution, was treated with 35% $H_2O_2$ prior to adsorbing colloidal flotation, the optimal pH for removing cobalt shifted m to weak alkaline range and flotation could be applied in wider range of pH as compared to non-use of $H_2O_2$. Additional use of 20 ppm Al(III) after precipitation of 50 ppm Co(II) with 50 ppm Fe(III) made the optimal pH range for preferable flotation w wider. Foreign ions such as, $NO_3^-$, $SO_4^{2-}$, $Na^+$, $Ca^{2+}$ were adopted and their effects were observed. Of which sulfate ion was f found to be detrimental to removal of cob퍼t ion by flotation. Coprecipitation of Co ion with Fe(III) and Al(III) resulted in b better removal efficiency of cobalt IOn 피 the presence of sulfate ion.

• Resources Recycling
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• v.7 no.3
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• pp.11-16
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• 1998

Simulated waste liquid containing 50 ppm cobalt ion was t$\xi$sted by precipitate flotation using a sodium lauryl sulfate as a c collector. The effects of initial cobalt ion concentration, pH, surfactant concentration, flotation time, gas flow rate and foreign i ions on removal efficiency of cobalt ion were studied. Pretreatment of the waste liquid with 35% $H_2O_2$, prior to precipitate f flotation made shin of optimal flotation pH from the strong alkalinity to weak alkaline range and made a favorable flotation of c cobalt ion in wide range of pH. For the result of this experiment, 99.8% removal efficiency was obtained on the conditions of initial coball ion concentration 50 ppm, pH 9.5 gas flow rate 70 mllmin, flotation time 30 min. The simulate ion was fanned t to be the most harmful ion against removal of cobalt by precipitate flotation of the species which were tested The presence of 0.1 M of $SO_4^{2-}$ ion decreased remo,때 $\xi$폐iciency of cobalt to 90% while the cobalt were almost entirely removed in the a absence of sulfate ion.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.17-28
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• 2010

A climbing lane is installed to separate low-speed traffic from high-speed traffic if drastic traffic capacity reduction is expected due to a large number of vehicles that slow down in the upward section. Existing studies on climbing lanes have focused on the designation, location of starting and ending points, and installation method of climbing lane with regard to road design standards. However, in terms of traffic operation, it was known that the climbing lanes cause traffic congestion due to the increase of traffic volumes. In this regard, this study aims to establish traffic operational guidance as to how much effects temporary closure of climbing lanes can have on traffic improvement according to the volume-capacity ratio, grade, and composition of trucks. A test section of simulated climbing lane was selected in Nakdong JC bound for Masan(136.9K~133.3K, 3.6km, 3.7%) on Jungbunaeryuk expressway to conduct VISSIM analyses, microscopic traffic simulation based on such control variables as traffic volume(v/c), grade and the trucks ratio. As a result of the analyses, it has been found that v/c and the ratio of trucks are the key variables for efficient traffic management of climbing lanes in order to relieve traffic congestion via climbing lane. If ratio of trucks are more than 50% and when v/c would be 0.8, both climbing lane would be closed and non-operated regardless of grade and ratio of trucks when v/c is 1.0. With the increased traffic due to a five-day work week system, continued peak hours during the weekday, increased and various patterns of congestion on expressway, this study would be expected to contribute to facilitating researches on flexible operational standards for road facilities.

• Journal of Korean Society of Transportation
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• v.21 no.4
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• pp.133-144
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• 2003

The current procedure of estimating accident reduction benefit shows fixed accident rates for each level of roads without considering the various characteristics of roadway geometries, and traffics. In this study, in order to solve the problems mentioned in the above, models were developed considering the characteristics of roadway alignments and traffic characteristics. The developed models can be used to estimate the accident rates on new or improved roads, In this study, only urban highways were included as a beginning stage. First of all. factors influencing accident rates were selected. Those factors such as traffic volumes. number of signalized intersections, the number of connecting roads, number of pedestrian traffic signals, existence of median barrier, and the number of road lane are also selected based upon the obtainability at the planning stage of roads. The relationship between the selected factors and accident rates shows strong correlation statistically. In this study, roads were classified into 4 groups based on number of lanes, level of roads and the existence of median barriers. The regression analysis had been performed for each group with actual data associated with traffic, roads. and accidents. The developed regression models were verified with another data set. In this study, in order to develop the proposed models, only data on a limited area were used. In order to represent whole area of the country with the developed models. the models should be re-analyzed with vast data.