• Journal of the Korean Wood Science and Technology
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• v.31 no.4
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• pp.24-30
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• 2003

In order to develop structural 'bamboo zephyr board', properties of boards produced by various methods making zephyr were estimated. All of boards were tested with KS(Korean Standards) F 3014 Particle board, and results were summarized as follow. The zephyr boards produced by final 1.5 mm roller space had the best properties(MOR, MOE and IB strength) among boards produced by different final roller space. Also, they had the best properties(MOR and MOE) in bending test after 1 hour soaking treatment after 2 hour-boiling in water, which were similar to properties of boards in dry-condition. Thickness swelling(TS) of all boards was less than 12% required to the Korean Standards A 3014. Zephyr boards produced by final 1.5 mm roller space also had the lowest values among all of boards. Boards produced by non-treatment (in green condition) had the better strength than those of boards produced by different pre-treatment methods(boiling in water and in 0.3% NaOH) in bending test.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.99-107
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• 1997

This study Provides the treatment methods of liquid wastes from the dissolution/purification process of nuclear fuel raw material and the fabrication process of nuclear fuel powder. One of the treatment methods is to process liquid waste from uranium raw material dissolution/purification process. This waste, of the strong acid, can be reused to dissolve the fine ADU particles in filtrate which is ADU waste of pH 8.0 converted from AUC waste after recovery of uranium. To dissolve the fine ADU particles, ADU filtrate was pretreated to pH 4.0 with the dissolution/purification waste, and then mixed with the lime to pH 9.2 and aged for 30 minutes. From this processing, uranium content of the filtrate was decreased to below 3ppm. The waste from fuel powder fabrication is emulsified solution dispersed with fine oil droplets. This emulsion was destroyed effectively by adding and mixing the nitric acid with rapid heating at the same time. After this processing, $Na_2U_2O_7$ compound is produced by addition of NaOH. Optimum condition of this processing was shown at pH 11.5, and uranium content of the filtrate was analyzed to 5ppm. To remove the trace of uranium in the filtrate, lime should be added. Otherwise, 4N nitric acid was used to destroy the emulsion directly, and then lime was added to this waste. Uranium content of the treated filtrate was below 1 ppm. In addition to these wastes, the trace of uranium in filtrate after recovery of uranium from the AUC waste which is produced during PWR power preparation, is treated with NaOH to takeup fluorine(F) in the waste because fluorine is valuable and toxic material. In the finally treated waste, uranium was not detected.

• Korean Journal of Plant Resources
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• v.21 no.2
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• pp.144-147
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• 2008

This study was conducted to clarify the characteristics of seed germination and to promote the germination rate in Pollia japonica Thunb. that was pointed to protect by the Office of Forestry in 1997. It was better the germination rate and the growth of in the light than those of in the darkness. The seed germination of Pollia japonica showed the highest germination rate at $20^{\circ}C$ any other treated temperature. To increase the germination rate of Pollia japonica, it was conducted priming treatments and storage treatments at $4^{\circ}C$. Priming treatments using 1% NaOH, 1% KOH for 30min were effective compared to control, but soaking of 100mg/L GA3 for 24 hours, 1% NaOCl for 30min were not useful. It was higher in wet storage than in dry storage. Wet storage of seeds showed a germination rate with 95.3% in 90-day treatment, which improved 55.3% than dry storage in 90-day.

• Applied Chemistry for Engineering
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• v.27 no.4
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• pp.371-379
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• 2016

In this article, the foamed body of glass was manufactured from the waste borosilicate glass produced by wet pulverization process without additional pretreatment which can be used as a recycling method for waste LCD panel glass. Each 100 g of pulverized waste borosilicate glass with the size of less than 270 mesh were mixed with 0.3 weight fraction of carbon and 1.5 weight fraction of $Na_2CO_3$, $Na_2SO_4$ and $CaCO_3$ and let them foamed for 20 minutes at $950^{\circ}C$ to manufacture the foamed body having the density of less than $0.3g/cm^3$. Additionally, adding $SiO_2$ or $H_3BO_3$ to the mixture enabled the foamed body to have efficient formation of open pores which showed the possibility for producing the foamed body with new functionalities such as sound absorption.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.104-104
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• 2011

섬유가 가늘어지면 굽힘 강성이 저하되고 비표면적이 증가하는 등의 많은 특징을 발휘한다. 특히 폴리에스테르 극세사는 실크와 같은 외관, 유연한 태 등의 감각적으로 우수한 특성을 가지므로 제품의 태에 대한 질적 향상을 요구하는 소비자의 욕구와 맞아떨어져 다양한 용도로 전개되고 있다. 초극세 섬유를 제조하는 방법은 통상적으로 멜트블로운법, 플래쉬법, 전기방사법 그리고 해도형 복합방사법의 4가지로 분류된다. 그중 해도형 복합방사법은 가장 안정적인 방법으로 PET기준으로 0.01데니어 급까지 상용화가 되어 있다. 해도형 복합섬유의 개발에 있어서 중요한 것 중에 하나가 해성분 폴리머의 용출기술이다. 초극세화를 목적으로 해성분인 변성폴리에스테르를 제거시키기 위해서 실시되는 알칼리(NaOH)에 의한 감량공정은 그 처리조건에 따라서 초극세사로 잔존해야하는 도성분의 정규 폴리에스테르까지 손상시킬 수 있기 때문에 균일한 용출조건의 확립은 매우 중요하다. 그러나 초극세화가 진행될수록 알칼리가 필라멘트의 가운데 영역까지 균일하게 침투하기가 어려우며 감량된 도성분도 비표면적이 증가하기 때문에, 해성분의 균일한 용출 및 감량을 위한 안정적인 조건을 선정하기가 어렵다. 따라서 본 연구에서는 울트라마이크로-나노급(800nm) 해도형 폴리에스테르 섬유를 이용하여 해성분 용출공정에서 정규 폴리에스테르를 손상시킬 수 있는 알칼리 감량 조건을 완화시키면서 기존과 동일한 감량 효과를 얻을 수 있는 용출 공정을 확립하고자 한다. 이를 위하여 유기산을 이용한 전처리 조건 및 알칼리 감량공정에서 NaOH의 농도, 처리시간, 처리온도의 변화가 울트라마이크로-나노급 해도형 섬유의 용출에 미치는 영향에 대하여 검토하였다.

• Journal of Energy Engineering
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• v.20 no.2
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• pp.84-89
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• 2011

In this study, individual(alkaline, ultrasonic) and combined(alkaline+ultrasonic) pretreatment effect on sewage sludge solubilization was investigated. COD solubilization rates increased with the dose of NaOH added: solubilization reached 27.6%. Additional alkaline agents did not increase solubilization further. Ultrasonic pretreatment achieved 33~39% solubilization when 140 W/L amplitude. In(alkaline(pre-treatment)+ultrasonic (after-treatment)) treatment, solubilization increased as the combined intensity in creased($70.4{\pm}9.4%$). SCOD rising rate(0.076) was achieved.

• KSBB Journal
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• v.8 no.2
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• pp.172-177
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• 1993

In order to reduce BOD of wastewater from alcohol distillery manufactory, the production of single cell lipid was attempted. Among five yeast strains tested, Rhodotorula glutinis was most desirable for lipid production. Wastewater was treated with 2N NaOH and used as a medium. The optimum pH and temperature for lipid production were found to be 5.0 and $30^{\circ}C$, respectively. The addition of monobasic phosphate was good for cultivation of Rhodotorula glutinis. The C/N ratio was an important factor for lipid production and composition. The best C/N ratio was 50 for the production of single cell lipid. By cultivation Rhodctorula glutinis for 4 days, 4g/L of single cell lipid was harvested and BOD of wastewater reduced by 88.7%.

• Journal of the Korean Applied Science and Technology
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• v.25 no.1
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• pp.58-64
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• 2008

Pretreatment of eliminating FFA is needed to make biodiesel from animal fat recovered from leather wastes because its acid value is high. This study was carried out to investigate the influence of 4 different pretreatment methods, which are heterogeneous catalyst method, ion exchange resin method, low pressure.high temperature method, and alkali method on the eliminating FFA and fatty acid composition. The results showed that the rate of eliminating FFA increased in the order of alkali method > catalyst method > low pressure high temperature method > ion exchange method. In the case of pretreatment of alkali method using NaOH, the rate of eliminating FFA appeared more than 86% regardless of acid value. Therefore, it was considered that alkali method using NaOH was the most effective in the view of economical and productive aspects, taking it into account that the acid value of animal fat recovered from fleshing scrap generated during leather making processes was 7 to 8.

• Membrane Journal
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• v.4 no.4
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• pp.213-220
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• 1994

Reverse osmosis(R/O) pilot system, which consists of pretreatments and R/O membranes, was demonstrated to regenerate the petroleum refinery wastewater for the process feedwater supply. Despite of the unsteady quality of the wastewater effluent from the process facilities, relatively high salt rejection of 96~99% was obtained and the product water showed a feasible quality for the use of cooling tower feed water. The results of R/O membrane module cleaning with NaOH solution represented that there was some fouling effects on the membrane performance during the period of test due to the ineffective treatment processes proposed and used in this study.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.4
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• pp.329-338
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• 2017

The problem of disposal of brine due to increased MD/RO desalination plant has recently become a big social issue. The chlor-alkali process through electrolysis of brine has been studied as a method to overcome this problem. In order to increase the electrolysis efficiency, a pretreatment process for removal of hard substances must be preceded. In this study, we investigated the mechanism of removal of hardness through chemical precipitation. As a result, Ca was greatly influenced by addition of $Na_2CO_3$, and Mg was strongly influenced by pH. Also, the addition of NaOH and $Na_2CO_3$ enabled simultaneous removal of Ca and Mg, and showed a removal efficiency of 99.9% or more. Finally, the residual concentrations of Ca and Mg in the brine after the reaction were 0.14 and 0.13 mg/L, respectively. Saturation index was calculated using Visual MINTEQ 3.1, and solid phase analysis of the precipitate was performed by FE-SEM and PXRD analysis. It was confirmed that precipitate formed by the formation of calcite and brucite.