• Journal of Korea Soil Environment Society
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• v.2 no.2
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• pp.53-60
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• 1997

A series of batch and lab-scale pilot tests were conducted to optimize the design parameters for the application of soil washing techniques to the soil contaminated by heavy metals. Cu, Pb, and Zn were selected as target heavy metals. The concentrations of Cu, Pb, and Zn were 500mg/kg dry soil, 1, 000mg/kg dry soil, and 500mg/kg dry soil, respectively. Citric acid and oxalic acid were used for the extractants. In the batch tests, the extraction efficiencies for Cu, Pb, and Zn were 79%, 72%, 72%, respectively. The proper extractant concentration and dilution ratio(weight/volume) for Cu and Pb were turned to be citric acid 50mM and 1:5, respectively. The extraction efficiencies were enhanced with the addition of 1~2% OA-5 or SDS. From pilot scale tests for Pb, first stage and second stage of soil washing resulted in the extraction efficiency of 59% and 78%, respectively.

• Journal of Pharmaceutical Investigation
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• v.34 no.3
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• pp.229-254
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• 2004

The objective of this study was to scrutinize the rationale of SUPAC-MR and its application in processing postapproval changes to modified release solid oral dosage forms. The types of postapproval changes that were primarily covered with SUPAC-MR included variations in the components and composition, the site of manufacturing, batch size, manufacturing equipment, and manufacturing process. SUPAC-MR defined levels of postapproval changes that the industry might make. Classification of such categories was based on the likelihood of risk occurrence and potential impact of changes upon the safety and efficacy of approved drug products. In most cases, the changes could be classified into 3 levels. It described what chemistry, manufacturing, and control tests should be conducted for each change level. The important tests specified in SUPAC-MR were batch release, stability, in vitro dissolution, and in vivo bioequivalence tests. It then suggested what type of a filing report should be submitted to the FDA for each change level. In general, level 1 changes could be reported in an annual report, whereas level 2 and/or 3 changes could be submitted in changes-being-effected or prior approval supplements. It could be understood that the purpose of SUPAC-MR was to maintain the safety and quality of approved modified release solid oral dosage forms undergoing certain changes. At the same time, it contributed to providing a less burdensome regulatory process with the manufacturers when they wanted to make postapproval changes. European regulatory agencies also implemented SUPAC-like regulations in handling such changes to drug products. Therefore, in this study a recommendation was made for KFDA and the Korean industry to evaluate thoroughly the usefulness of these guidances and regulations in dealing with postapproval changes to modified release solid oral dosage forms.

• Nuclear Engineering and Technology
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• v.6 no.4
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• pp.231-237
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• 1974

For detection and localization of leaks in closed vessels or pipes carrying liquid flow, $^{51}$ Cr-EDTA and $^{51}$ Cr-DTPA were synthesized and, the column and batch equilibrium experiments were carried out. In the column experiment, the recovery of $^{51}$ Cr-EDTA is 100% in quartz sand and 80.9% in steel sawdust, and that of $^{51}$ Cr-DTPA is 77.4% in quartz sand and 6.4% in steel sawdust. The recovery curve. $^{51}$ Cr-DTPA system in steel sawdust does not show a certain plateau, exceptionally. In general, $^{51}$ Cr-EDTA is adsorbed less than $^{51}$ Cr-DTPA. In the batch equilibrium experiment, the distribution coefficients (Kd) and effect of pH were investigated by using quartz sand, montmorillonite, steel sawdust, and mixed cement raw material as media. In general, the Kd values for $^{51}$ Cr-EDTA are lower than that of $^{51}$ Cr-DTPA. The Kd values for $^{51}$ Cr-EDTA are almost zero at pH 6.0, 7.0, and 8.0.

• Journal of the Korean Data and Information Science Society
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• v.28 no.6
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• pp.1245-1255
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• 2017

The online learning is a process of obtaining the solution for a given objective function where the data is accumulated in real time or in batch units. The stochastic gradient descent method is one of the most widely used for the online learning. This method is not only easy to implement, but also has good properties of the solution under the assumption that the generating model of data is homogeneous. However, the stochastic gradient method could severely mislead the online-learning when the homogeneity is actually violated. We assume that there are two heterogeneous generating models in the observation, and propose the a new stochastic gradient method that mitigate the problem of the heterogeneous models. We introduce a robust mini-batch optimization method using statistical tests and investigate the convergence radius of the solution in the proposed method. Moreover, the theoretical results are confirmed by the numerical simulations.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.6
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• pp.864-873
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• 2013

In developing countries, biogas energy production is seen as a technology that can provide clean energy in poor regions and reduce pollution caused by animal manure. Laboratories in these countries have little access to advanced gas measuring equipment, which may limit research aimed at improving local adapted biogas production. They may also be unable to produce valid estimates of an international standard that can be used for articles published in international peer-reviewed science journals. This study tested and validated methods for measuring total biogas and methane ($CH_4$) production using batch fermentation and for characterizing the biomass. The biochemical methane potential (BMP) ($CH_4$ NL $kg^{-1}$ VS) of pig manure, cow manure and cellulose determined with the Moller and VDI methods was not significantly different in this test (p>0.05). The biodegradability using a ratio of BMP and theoretical BMP (TBMP) was slightly higher using the Hansen method, but differences were not significant. Degradation rate assessed by methane formation rate showed wide variation within the batch method tested. The first-order kinetics constant k for the cumulative methane production curve was highest when two animal manures were fermented using the VDI 4630 method, indicating that this method was able to reach steady conditions in a shorter time, reducing fermentation duration. In precision tests, the repeatability of the relative standard deviation (RSDr) for all batch methods was very low (4.8 to 8.1%), while the reproducibility of the relative standard deviation (RSDR) varied widely, from 7.3 to 19.8%. In determination of biomethane concentration, the values obtained using the liquid replacement method (LRM) were comparable to those obtained using gas chromatography (GC). This indicates that the LRM method could be used to determine biomethane concentration in biogas in laboratories with limited access to GC.

• Journal of Animal Science and Technology
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• v.52 no.6
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• pp.513-519
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• 2010

A series of experiments were performed to study the influence of the following parameters on the physical traits and composition of swine manure compost: (1) addition of magnesium (Mg) at a molar ratio of 1.2 with respect to $PO_4$, and (2) reutilization of compost containing $MgNH_4PO_4{\cdot}6H_2O$ (magnesium ammonium phosphate, MAP). Three independent batch tests were conducted for replication: batch test I-control (C) and Mg added (T), batch test II-C, T and compost recycle ($T_{R1}$), and batch test III-C, T and compost recycle ($T_{R2}$). Magnesium addition and compost reutilization had no adverse effect on the degradation of organic matter. Reuse of the compost, however, had a clear effect on the total nitrogen (TN) and total phosphorus (TP) contents in the final compost. Repeated compost reutilization as a bulking material was resulted in composts rich in N and P. Upon adding the Mg supplement to the composting materials, the ortho-phosphate (OP) to TP ratio decreased due to the MAP crystallization reaction. The decrease in the OP/TP ratio and the increase in the TP content of the compost indicate that water-soluble phosphate is converted into a slow-release phosphate by the formation of crystals during composting. X-ray diffraction analysis of the irregular shaped crystals in the compost indicated that they are MAP crystals and that the crystallization of MAP begins immediately after the addition of the Mg supplement. The Mg addition to composting materials and the reutilization of compost as a bulking material would be a practical means to conserve nutrient content.

• Korean Journal of Materials Research
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• v.33 no.7
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• pp.265-272
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• 2023

In this study, the synthesis of nitrobenzene was carried out using sulfated silica catalyst. The study delved into H₂SO₄/SiO₂ as a solid acid catalyst and the effect of its weight variation, as well as the use of a microwave batch reactor in the synthesis of nitrobenzene. SiO₂ was prepared using the sol-gel method from TEOS precursor. The formed gel was then refluxed with methanol and calcined at a temperature of 600 ℃. SiO₂ with a 200-mesh size was impregnated with 98 % H₂SO₄ by mixing for 1 h. The resulting 33 % (w/w) H₂SO₄/SiO₂ catalyst was separated by centrifugation, dried, and calcined at 600 ℃. The catalyst was then used as a solid acid catalyst in the synthesis of nitrobenzene. The weights of catalyst used were 0.5; 1; and 1.5 grams. The synthesis of nitrobenzene was carried out with a 1:3 ratio of benzene to nitric acid in a microwave batch reactor at 60 ℃ for 5 h. The resulting nitrobenzene liquid was analyzed using GC-MS to determine the selectivity of the catalyst. Likewise, the use of a microwave batch reactor was found to be appropriate and successful for the synthesis of nitrobenzene. The thermal energy produced by the microwave batch reactor was efficient enough to be used for the nitration reaction. Reactivity and selectivity tests demonstrated that 1 g of H₂SO₄/SiO₂ could generate an average benzene conversion of 40.33 %.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.06a
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• pp.43-49
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• 1998

Retardation effect of heavy metals in soils caused by adsorption onto the surfaces of solids particles is well known phenomena. The adsorption of metal ions has been recognized more strong in clay mineral and organic matter contents rather than sands and gravels. In this study, we investigated the retardation effect in two sandy soils by conducting batch and column tests. The column tests were conducted to obtain the relationship between concentration and time known as breakthrough curve (BTC). We applied pulse type injection of ZnCl$_2$solution on the inlet boundary and monitored the effluent concentration at the exit boundary under steady state condition using EC-meter and ICP-AES. Batch test consisted of an equilibrium procedure for fine fractions collected from two sandy soils for various initial ZnCl$_2$concentrations, and analysis of Zn ions in equilibrated solution using ICP-AES. The results of column test showed that i) the peak concentration of Zn analyzed by ICP was far less than that detected by EC-meter for both soils and ii) travel times for peak concentration were more less identical for two different monitoring techniques. The first result can be explained by ion exchange between Zn and other cations initially present in the soil particles since ICP analysis showed a significant amount of Ca, Mg ions in the effluent. From the second result, we found that retardation effect was not present in these soils due to strong cation exchange capacity of Zn ion over other cations since we did not apply a solution containing more adsorptive cations such as Al. The result of batch test also showed high distribution coefficients (K$_{d}$) for two soils supporting the dominant ion exchange phenomena. Based on the retardation factor obtained from the Kd, we predicted the BTC using CDE model and compared with the BTC of Zn concentration obtained from ICP The predicted BTC, however, disagreed with the monitored in terms of travel time and magnitude of the peak concentrations. The only way to describe the prominent decrease of Zn ion was to introduce decay or sink coefficient in the CDE model to account for irreversible decrease of Zn ions in liquid phase.e.

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.1-12
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• 2012

In this study, $CO_2$ adsorbent was developed for removing low concentration of $CO_2$ in multiple-use facilities. The efficiency of the adsorbent which was improved selective $CO_2$ adsorption capabilities was evaluated. The pellet type adsorbent was modified from a commercial zeolite with mixing LiOH, binder, additives, and $H_2O$. Column tests showed over 90 % of $CO_2$ was adsorbed within 400min. Chamber tests including batch and continuous types were performed for evaluating the adsorbent module. By batch tests, it was evaluated that about 92% of $CO_2$ was removed within 30 min. By continuous tests, 70% of $CO_2$ was removed within 30 min. It was analyzed that over 2,500 ppm of $CO_2$ was continuously removed as shown chamber tests. The reproducibility tests repeatedly performed for 15 days shows that over 1,000 ppm of $CO_2$ was continuously removed. Adsorption capacity of the developed adsorbent was 5.0mmol $CO_2/g$ adsorbent which was analyzed by TGA. It was estimated that the modified adsorbent was applicable to low $CO_2$ concentration and low temperature of indoor environment.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.95-98
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• 2003

Waste lime is produced as by-products in chemical industry, Reuse of waste lime mixed with soil for banking and backfill material in civil works was analysed in this study. For this purpose, environmental effect of waste lime admixtures was tested. Thus, this study presents the leaching characterization of waste lime in laboratory batch and column tests. Countermeasure for reduction of environmental effects was suggested from the test results.