• Resources Recycling
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• v.26 no.6
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• pp.29-37
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• 2017

Nuclear fuel cladding tube is fabricated by pilgering and annealing process. In order to remove impurity and oxygen layer on the surface, pickling process is carried out. When Zirconium(Zr) is dissolved and saturated in acid solution during the pickling process, all the waste acid including Zr is disposed. Therefore, $BaF_2$ is added into the waste acid to extract Zr and $Ba_2ZrF_8$ is subsequently formed. To recycle Zr by electrowinning process, $Ba_2ZrF_8$ is used as electrolyte, but it has high melting point ($1053^{\circ}C$). $ZrF_4$ should be added into $Ba_2ZrF_8$ to decrease the melting point. In this paper, it was investigated that $Ba_2ZrF_8$ was separated to $BaF_2$ and $ZrF_4$ by vacuum distillation. Firstly, $BaF_2$ with different particle size ($1{\mu}m$, $35{\mu}m$, $110{\mu}m$) was added into the waste acid and the respective precipitation property was estimated. $BaF_2$ obtained by vacuum distillation was shattered by ball-milling with different time. The precipitation efficiency was compared with $1{\mu}m$ of ${BaF_2}^{\prime}s$ one, which was not used as precipitation agent.

• Resources Recycling
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• v.12 no.1
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• pp.33-40
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• 2003

Mn was extracted by using a nitric acid from the reduced ferromanganese dust and the basic experiments were taken to refine the manganese nitrate solution by means of precipitation of Ca, Mg oxalate. The dust was generated in AOD process producing a medium-low carbon ferromanganese and collected in the bag filter. Manganese oxide content in the dust was about 90% and its phase was confirmed as $Mn_3$$O_4$. $Mn_3$$O_4$ in the dust was reduced to MnO by roasting with activated charcoal. The main impurities in the extracted solution prepared by leaching the reduced dust with nitric acid were Na, K, Fe, Si, Ca, Mg etc. Among them, Fe was removed by controlling pH of the solution more than 4 and precipitating $Fe(OH)_3$, simultaneously silicious material solved in the solution was removed by co-precipitation with the ferric hydroxide. Addition of 150 g reduced dust into 4N HNO3 solution 1$\ell$ was appropriate to control the pH of the solution to pH 4. To differ greatly the solubilities of manganese oxalate and calcium or magnesium oxalate in a solution containing a high concentration of Mn, pH of 4 or less and addition of ($NH_4$)$_2$$C_2$$O_4$ in equivalent with Ca and Mg are recommended. At this time, the higher temperature was the shorter the precipitation reaction time was needed.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.140-143
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• 2001

A study has been made on the recovery of nitric acid and valuable metals such as Cu, Sn, Pb from the spent nitric etching solutions. The nitric acid was extracted effectively by TBP but the heavy metals such as Fe, Cu, Sn, Pb were not extracted by TBP from the spent nitric etching solutions. From the experimental results, 95% of nitric acid in spent etching solution was extracted at O:A ratio of 3:1 with five stage by 60% TBP and 98% of nitric acid was stripped from the loaded organic phase at O:A ratio of 1:1 with four stages by distilled water. After extracting nitric acid, Cu was recovered as a metal by electrowinning effectively and Sn was successfully removed by precipitation method by adjusting the pH of raffinate solution. Finally, Pb was recovered by cementation with iron scrap at $65^{\circ}C$. Parameters controlling the cementation process, such as temperature, pH and the effect of the additives were investigated.

• Food Engineering Progress
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• v.15 no.4
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• pp.289-296
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• 2011

Twenty four fractions by solvent extraction and/or acid precipitation from fruit body and culture broth of Inonotus obliquus were prepared, and their inhibitory effect against acetylcholinesterase (AChE) was investigated. Among these fractions, acid (1 M HCl) precipitates from cell-free culture broth and fruit body exhibited the highest inhibitory effect on AChE in vitro. Acid precipitates inhibited AChE activity in a concentration-dependant manner and $IC_{50}$ values of both acid precipitates were 0.53 mg/mL. The inhibition pattern was general non-competitive inhibition. The energetic parameters were also determined by dual substrate/temperature design. Both acid precipitates increased the values of Ea, ${\Delta}H,/;{\Delta}G$ and ${\Delta}H^{\ast}$ decreasing the value of ${\Delta}S$ for AChE. The results implied that the acid precipitates from I. obliquus increased the thermodynamic barrier, leading to the breakdown of ES complex and the formation of products as inhibitory mechanism.

• Journal of Applied Biological Chemistry
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• v.51 no.3
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• pp.88-94
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• 2008

Three different protein extraction methods-phenol extraction, trichloroacetic acid (TCA) precipitation, and desalting/TCA precipitation-were compared to determine the optimal reproducible high resolution 2-dimensional (2-D) electrophoresis for each chungkugjang, doenjang, and kochujang samples. The soluble proteins from Chungkugjang extracted by phenol were separated with high reproducibility and resolution, and gained 1.75- to 3-fold more protein spots on 2-D gel than those from the other methods. On the contrary, the extracted proteins from doenjang and kochujang treated by desalting/TCA precipitation method showed about 1.5- to 3.3-fold more protein spots on 2-D gel. Using the established methods, the changes in the protein profiles of the fermented soy foods were monitored during the fermentation period by 2-DE. One of the major proteins in soy, $\beta$-conglycinin $\alpha$-subuint, and some proteins with unknown functions were localized on 2-D gel as the protease-resistant proteins throughout the fermentation period of doenjang. Changes in the protein profile monitored by the established methods can provide basic information on unfolding the mechanisms of the generation of biofunctional activity in the fermented soy foods.

• Journal of Environmental Science International
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• v.2 no.4
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• pp.337-346
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• 1993

The amount of inorganic ions such as $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $NH_4^+$, $Cl^-$, $NO_3^-$, and $SO_4^{2-}$ in the precipitation at hongwon area were analyzed during the period of February 1991 - June 1993. Ammonium ion was analyzed using Messier and indophenol methods. Cations were determined by atomic absorption spectroscopy, and ion chromatography was used for anions. For the entire period of study, there was no particular ion which has significant]y high correlation coefficient with hydrogen ion. The correlation between $NO_3^-$, and $SO_4^{2-}$ was 0.6, which suggests that these ions may be from the same source. Most cations have high correlation with each other. In the seasonal analysis, the nitrate and sulfate ions have high correlations with the acidity in the fall and winter. The rain waters of Taeahn area showed usually high concentrations of the ions, even though the pH was much higher than that of Chongwon area. It is considered that the ions came as neutral salt in Taeahn, while $NO_x$ and $SO_x$ contributes largely to the acidity of rains in Chongwon.

• Proceedings of the KIEE Conference
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• 2000.07e
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• pp.26-28
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• 2000

A novel oxidant generation and ion precipitation cell with slits on parallel plate electrodes system has been proposed and an effect of the number and size of slits on ion precipitation and oxidant generation characteristics. As a result, with the electrodes with 48 slits($S=200{\times}60[mm^2]$. d = 1.5, 5.0 [mm]), it is found that the oxidant contained waters of 17.0 [ppmm] and 23.5 [ppmm] in acid water were obtained with 0.1 [wt%] NaCl dissolved tap water fed. And oxidant contained waters of 0.5 [ppmm] and 1.5 [ppmm] in alkali water were obtained with 0.1 [wt%] NaCl dissolved tap water fed. And the oxidant contained waters of 7.0 [ppmm] and 11.5 [ppmm] in mixed water were obtained with tap water and 0.1 [wt%] NaCl dissolved tap water fed. Consequently, very high ion precipitation and dense oxidant generation characteristics can be realized by having slits on the electrodes of conventional cells as these slits increase the electric fields and decrease the space charge limiting actions in interelectrode space.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1150-1154
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• 2009

Low levels of virus contamination and naturally occurring reverse transcription-polymerase chain reaction (RT-PCR) inhibitors restrain virus detection in oysters. A rapid and efficient oyster-processing procedure that can be used for sensitive virus detection in oysters was developed. Poliovirus type 1 Sabin strain was used to evaluate the efficacy of virus recovery. The procedure included (a) acid-adsorption and elution with buffers (0.25M glycine-0.14 M NaCl, pH 7.5; 0.25M threonine-0.14M NaCl, pH 7.5); (b) polyethylene glycol (PEG) precipitation; (c) resuspension in Tween 80/Tris solution and chloroform extraction; (d) the second PEG precipitation; (e) viral RNA extraction with TRIzol and isopropanol precipitation; and (f) RT-PCR combined with semi-nested PCR. The overall recovery of elution/concentration was 19.5% with poliovirus. The whole procedure usually takes 19 hr. The overall detection sensitivity was 4 RT-PCR units of genogroup I norovirus (NoV) and 6.4 RT-PCR units of genogroup II Nov/25 g of oysters initially seeded. The virus-detecting method developed in this study should facilitate the detection of low levels of NoV in oysters.

• Korean Journal of Veterinary Research
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• v.4 no.1
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• pp.19-22
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• 1964

The alcohol precipitation test(APT) is widely used in the inspection of cow milk, whereas the APT in goat milk inspection is not specifically known. The APT is used to determine the precipitating ability of milk by heat used in sterilization and evaporating process at the milk plant. The APT may also be used to detect abnormal milks such as acid milk, colostrum, and any milk in which the salt balance is disturbed so that it may be more subject to precipitation than normal milk. In the experiments the applicability of the APT of goat milk was studied. The results obtained by using 87 sample of goat milk are as follows: 1. As all the fresh samples(100%) were APT positive by using 70% ethanol which is used in the practice of cow milk and 3 out of 87 samples(3.7%) were positive by using 45% ethanol, it is suggested that 45% ethanol may be applied in the APT of goat milk. 2. The distribution of natural acidity (apparent acidity) was between 0.12%-0.30% and the amount of natural acidity did not significantly affect the precipitating ability of goat milk by APT. 3. The freshness of goat milk cannot be detected sharply by APT even though 45% ethanol is applied.

• Journal of Nutrition and Health
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• v.18 no.4
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• pp.312-317
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• 1985

This study was attempted to investigate the occurrence and the characteristics of ascorbic oxidase in cucumbers. Ascorbic acid oxidase was isolated from cucumbers and concentrated using ammonium sulfate precipitation. The results of this study are as follows ; 1) Ascorbic acid oxidase activity was detected in whole cucumber homogenate. 2) Highest amounts of ascorbic acid destroyed after 10 minutes' incubation of ascorbic acid oxidase with its substrate. 3) The optimum pH and temperature of this enzyme were found to be pH 6.5 and $40^{\circ}C$, respectively. 4) Ascorbic acid content in cucumber juice prepared using the cold water $(4^{\circ}C)$ was higher than that made with water at $30^{\circ}C$. 5) When orange juice ( pH 3.4 )was added, ascorbic acid destruction was completely ceased. (The ascorbic acid oxidase was inactivated at pH 3.9) Decreasing the temperature and pH are recommended to achieve maximum stability of ascorbic acid in preparing cucumber juice.