• Journal of the Korea Concrete Institute
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• v.18 no.2 s.92
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• pp.267-274
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• 2006

Greenhouse gas reduction will be highlighted as the most pending question in the cement industry in future because the production of Portland cement not only consumes limestone, clay, coal, and electricity, but also release waste gases such as $CO_2,\;SO_3$, and NOX, which can contribute to the greenhouse effect and acid rain. To meet the increase of cement demand and simultaneously comply with the Kyoto Protocol, cement that gives less $CO_2$ discharge should be urgently developed. This study aims to manufacture non-sintering cement(NSC) by adding phosphogypsum(PG) and waste lime(WL) to granulated blast furnace slag(GBFS) as sulfate and alkali activators. This study also Investigates the hydration reaction of NSC through analysis of scanning electron microscopy(SEM), X-ray diffraction(XRD), differential thermal analysis(DTA), and pH. Results obtained from analysis of the hydrate have shown that the glassy films of GBFS are destroyed by the activation of alkali and sulfate, ions eluted from the inside of GBFS react with PG and produce ettringite, and consequently the remaining component in GBFS slowly produced C-5-H(I) gel. Here, PG is considered not only to play the role of simple activator, but also to work as a binder reacting with GBFS.

• Analytical Science and Technology
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• v.10 no.2
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• pp.91-104
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• 1997

Scutellariae radix has been used on the control of body fever as oriental medicine for thousand years. Analytical aspect for the main components of Scutellariae radix was set up improving sensitivity and resolution. The analysis of 3 different flavonoids present in Scutellariae radix-baicalin, baicalein, wogonin-was conducted by means of high performance liquid chromatography with ODS reverse phase column in conjunction with a Photo Diode Array UV detector(280nm) at $40^{\circ}C$. Mobile phase was carried out at 1mL/min, composed of acetonitrile and 0.1M phosphoric acid in the form of a gradient method. Under these circumstances the retention time for baicalin, baicalein, wogonin was 7.65, 11.65 and 14.12 minutes respectively. As a result for the efficiency on extraction of active ingredients with proposed analytical process according to it's growing districts, Sunchang in Junbuk for baicalin and Bulkyo in, Junnam for bicalein and wogonin have shown the best results. Even the extraction at room temperature was satisfactory. Among acids, 0.1M acetic acid revealed the best achievements. The mixture of acetonitrile and 0.2M phosphoric acid(75:25) has been shown the best efficiency as well as stability for the extraction of active ingredients.

• Applied Biological Chemistry
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• v.36 no.6
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• pp.510-516
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• 1993

The degradation and leaching pattern of benzoylurea insecticide teflubenzuron and flucycloxuron in soil environment and their effect on urease activity were investigated. The half-life of teflubenzuron was 39.1 days and 20.9 days in Chilgok and Ansim soil of nonsterilized condition, respectively, and that of flucycloxuron was 102.3 days and 50.1 days. Teflubenzuron and flucycloxuron were degraded more rapidly in Ansim soil with rich organic matter than Chilgok soil, and were degraded very slowly under sterilized condition. Their degradation seemed to be mainly mediated by microorganisms in soil. Teflubenzuron was degraded 63.2 days and 29.2 days faster than flucycloxuron under nonsterilized condition of Chilgok and Ansim soil. The inhibition of urease by the pesticides in two kinds of soil was strongly affected $(37.6{\sim}42.4%)$ in the early stage of their treatment but hardly affected or increased a little after 120 days. The teflubenzuron and flucycloxuron remained in the upper 5 cm of the soil column after elution with 1,000 ml of water, and they were not detected in leachate.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.2
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• pp.179-186
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• 2006

Chemical wastes are generated from nuclear facilities and R&D laboratories, but the uranium concentration in the final dried cake is evaluated into 11.2 Bq/g, which exceeds the exemption level of 10 Bq/g for each U isotopes, so the cake is categorized into a radioactive waste. Acid dissolution was applied to extract uranium from the waste sludge, and uranium adsorption on the dissolved solution was experimented by using IRN-77 and Diphosil bead. A large amount of resin was required to get above 80% of uranium removal, which was found to be due to a large amount of metal ions simultaneously dissolved from the precipitates with uranium. As an alternative method, acid dissolution is applied to the dewatered wet cake of the sludge, and the natural evaporation method is adopted for the dissolved solution. The uranium concentration of the dissolved solution was estimated to be 6.97E-01 Bq/ml, and the specific activity of the final waste sheets is evaluated to be 4.3 Bq/g. These results lead to the suggestion that the application of acid dissolution to the wet cake and the natural evaporation for the dissolved solution is an effective treatment method for chemical wastes containing uranium.

• Resources Recycling
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• v.15 no.2 s.70
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• pp.18-23
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• 2006

Foaming of slag is a thermodynamically unstable phenomenon and has significant effects in iron and steelmaking processes. For better recycling method of pulp sludge, the application as an defoaming agent during steelmaking process was adopted and tested. The forming machine has been modified in order to produce the briquettes, which are made of pulp sludge and slag with different weight ratio. Influencing factors on the foaming phenomena have been studied and tested for better understanding of foaming phenomena. Experiments were carried out with $CaO-FeO-SiO_2$ based slags with Ar gas injection and addition of coke particles. The slag basicity and (%FeO) contents adapted as major factors to treasure foaming tendency of the slag system. It was found that foam index (${\Sigma}$) gradually decreased as both the basicity and the (FeO) content increase. Four kinds of antifoaming agent such as aluminium dross, cokes, rice bran and pulp sludge with steelmaking slag have been tested in actual process. Aluminium dross was the most effective, and pulp sludge with steelmaking slag also showed the desired results.

• Journal of the Korean Wood Science and Technology
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• v.33 no.6 s.134
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• pp.95-100
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• 2005

The using amount of preservative-treated wood equipments has been increased. Specially, chromate copper arsenate (CCA) has been widely used to exterior wood. We are faced to the disposal problem after service period of CCA treated wood due to its toxic heavy metals. For the disposal of end-used treated wood, land-filling and incinerating methods are mainly applied. The essential problem of incinerating is an arsenic release into atmosphere. Low pyrolysis is suggested as the methods of protecting arsenic release during incineration. The heavy metals were recovered after combustion of the treated wood at the low temperature which arsenic can not released. The recovery amounts of effectiveness compounds was determined in various solvents (citric acid, nitric acid, sulfuric acid, acetic acid, phosphoric acid) and different temperature (300, 400, $500^{\circ}C$). The higher temperature was applied, the more copper was recovered. The chromium was difficult to be recovered on the carbonized CCA treated wood at 0.5% acid concentration. The recovery mass of arsenic decreased on the higher combustion treated wood. The recovery of chromium was difficult due to the chemical change of the chromium arsenate during pyrolysis.

• Polymer(Korea)
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• v.27 no.5
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• pp.464-469
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• 2003

In this work, the fragrant oil release behavior of poly($\varepsilon$-caprolactone) (PCL) microcapsules containing SiO$_2$ was investigated. The SiO$_2$ was chemically treated in 10, 20, and 30 wt% hydrochloric acid and sodium hydroxide. The acid and base values were determined by Boehm's titration technique and $N_2$/77 K adsorption isotherm characteristics, the specific surface area and total pore volume were studied by BET. The PCL microcapsules containing SiO$_2$ and fragrant oil were prepared by oil-in-water (o/w) emulsion solvent evaporation method. The shape and surface of PCL microcapsules were observed using image analyzer and scanning electron microscope (SEM). The fragrant oil release behavior of PCL microcapsules was characterized using UV/vis. spectra. The average diameters of PCL microcapsules were decreased from 35 to 21 $\mu$m with increasing stirring rate. It was found that in the case of acidic treatment the fragrant oil adsorption capacity and release rate were increased due to the increase of specific surface area and acid value. In the case of basic treatment, the fragrant oil adsorption capacity and release rate were decreased due to the decrease of sp ecific surface area and the increase of acid-base interactions between SiO$_2$-NaOH and fragrant oil with increasing base value of SiO$_2$.

• Resources Recycling
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• v.17 no.4
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• pp.3-9
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• 2008

The total amount of fluidized bed incinerator ash, i.e. incombustion materials generated from the municipal solid waste incineration(MSWI) in Korea was approximately 14,000 tons in 2006. Most of the ash after ferrous metal separation is finally discard to the landfill sites. In the present work, possibility for recycling of the ash is studied to utilize the ash as raw materials for ceramic products. Incombustion materials obtained from the two different incinerators were used to recover the raw materials by applying the magnetic separation and screening process to remove metallic particles. The raw materials show relatively low heavy metals content obtained from the KSLP leaching tests. The ceramic products were prepared by mixing the clay with the various amounts of the raw material. The physical properties, i.e. shrinkage rate, absorbancy and compressive strength of the ceramic products sintered at $1,000^{\circ}C$ and $1,050^{\circ}C$, respectively were improved by increasing the addition amounts of the incinerator ash. Based on the leaching tests the ceramic products also be satisfied with the standard limits on the leachability of heavy metals because most of the metallic materials are effectively removed from the incombustion materials by appling the separation processes.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.4
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• pp.365-372
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• 2006

A dynamic compartment model is presented to predict the contamination level of agricultural plant by $^{137}C_s$ as a result of a soil deposition. The model considered the processes of a percolation, soil mixing by a plowing before transplanting, plant uptake, leaching to a deep soil, and fixation to a clay mineral. The effects of the soil properties (pH, clay mineral, organic matter content, and exchangeable K), which are spatially varied, on a plant uptake and the leaching rates of $^{137}C_s$ in a root zone soil were modeled by the Absalom model. To test the validity of the model, the $^{137}C_s$ aggregated transfer factors(TFa) for rice plants were compared with those observed from some simulated $^{137}C_s$ soil deposition experiments, which were carried out with respect to rice plants cultivated in seventeen paddy soils of different properties for two consecutive years. Observed $^{137}C_s$ TFa values of the rice plants did not show an evident trend for the pH and clay content of the soil properties, while they increased with an increasing organic matter content or a decreasing exchangeable K concentration. Predicted $^{137}C_s$ TFa values of the rice plants were found to be comparable with those observed.

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.42-49
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• 2017

To replace phthalate plasticizer for PVC, acetylated monoglyceride (AMG) plasticizers were prepared from plant oil and their plasticization effects were also investigated. Transesterification of coconut oil by glycerol followed by acetylation with acetic anhydride gave AMG-CoCo (Coco : Coconut Oil). In addition, AMG-GMO (GMO : Glycerol monooleate) and AMG-GMO-Epoxy were synthesized by acetylation and epoxidation with glycerol monooleate. It was found that the thermal stability of AMG plasticizers increased in the following order: AMG-GMO-Epoxy > AMG-GMO > AMG-CoCo and all three plasticizers were thermally more stable than those of common petroleum-based plasticizer DOP (Dioctyl phthalate). The tensile strain values of the PVC containing AMG compounds were ca. 770~810%, while tensile strength values were ca. 19~22 MPa, which were higher than those of PVC containing DOP. DMA (Dynamic Mechanical Analysis) results showed that the miscibility of AMG-GMO-Epoxy in PVC was excellent and the $T_g$ of PVC containing AMG-GMO-Epoxy at 50 phr decreased down to $24^{\circ}C$. Finally, the leaching experiment result showed that the weight loss values of PVC containing AMG-GMO and AMG-GMO-Epoxy at 50 phr were as low as 2 and 1%, respectively, indicating that they have high water migration resistance. The above findings suggested that AMG-GMO-Epoxy could be one of plant oil-based PVC plasticizers to replace DOP.