• Title/Summary/Keyword: 변화

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말쥐치 내장유의 특성 (Characteristics of Filefish Viscera Oil)

  • LEE Eung-Ho;KIM Jin-Soo;JOO Dong-Sik;KIM Poong-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.25 no.3
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    • pp.236-240
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    • 1992
  • To obtain the applicable data for fish oil utilization, the characteristics of filefish viscera oil were studied. The lipid content showed the lowest value$(38.8\%)$ from viscera of filefish caught in April and the highest value$(59.5\%)$ in July. The seasonal variation in fatty acids showed a tendency of high level of polyenes such as 20:5 and 22:6 and low level of saturates such as 16:0 and 18:0 during the spawning season. While level of monoenes such as 18:1 was low regardless of seasons. The viscera of filefish caught in April contained $46.7\%$ total lipid(TL) which consisted of $94.3\%$ neutral lipid(NL), $1.6\%$ glycolipid(GL) and $4.1\%$ phospholipid(PL). The NL of filefish viscera mainly consisted of triglyceride$(88.1\%)$ and had esterified sterol and hydrocarbon, free sterol, diglyceride and free fatty acid in less quantity. The major fatty acids in TL and NL were 16:0, 18:0, 18:1, 20:5 and 22:6.

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Macrobenthic community on the soft-bottom around the Youngjong Island, Korea (영종도 주변해역의 저서동물 군집)

  • LIM Hyun-Sig;LEE Jae-Hac;CHOI Jin-Woo;Je Jong-Geel
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.28 no.5
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    • pp.635-648
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    • 1995
  • Macrobenthic fauna were collected seasonally using the van Veen Grab $(0,1/m^2)$ to investigate the benthic faunal assemblages on the soft-bottoms around the Youngjong Island during October 1991 to July 1992. A total of 266 species was identified. Of these polychaetes comprised 111 species $(41.7\%)$; crustaceans $75(28.2\%)$ molluscs, $59 (22.2\%)$ and others including echinoderms, $27(7.9\%)$. Mean density and biomass were estimated to be 498 $ind./m^2$ and 54.8$g./m^2$, respectively. Polychaetes were the most dominant faunal group in terms of abundance $(332\;ind./m^2)$ and number of species as well, whereas echinoderms were predominant in biomass $(332\;g./m^2)$. The dominant species were Mediomastus sp., Heteromastus sp., Nipponomysella oblongata, and Nephts polyranchia; the abundance of these species showed seasonal variations. The study area was divided into three regions by cluster analysis based on the similarity of species composition. The first region consisted of intertidal flat (G-I); the second, shallow subtital region of muddy sand (G-II); the third, channel region of mud sediments (G-III). The intertidal flat showed the highest density, and the channel was the lowest density, but the Highest in species diversity. Distribution of macrobenthic faunal assemblages of the study area seemed to be controlled by sedimentary facies and duration of tidal exposure.

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Adsorption Features of Lead Ion on Waste Undaria pinnatifida (폐기된 해조류를 이용한 납 이온의 흡착 특성)

  • Seo Myung-Soon;Kim Dong-Su
    • Resources Recycling
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    • v.13 no.4
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    • pp.23-31
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    • 2004
  • Basic studies have been conducted regarding the attempt of the utilization of waste Undaria pinnatifida as an adsorbent for the adsorption treatment of lead-containing wastewater. Undaria pinnatifida was found to be chiefly composed of hyo-carbonaceous compounds and have a fairly high specific surface area, which suggesting the possibility of its application as a Potential adsorbent. The electrokinetic Potential of Undaria pinnatifida particles was observed to be negatively highest at around pH 8 and the fact that its electrokinetic potentials are negative at the whole pH range supported it might be an efficient adsorbent especially for cationic adsorbates. Under the experimental conditions, $Pb^{2+}$ was found to mostly adsorb onto Undaria pinnatifida within a few minutes and reach the equilibrium in adsorption within ca. 30 minutes. The adsorption of $Pb^{2+}$ was exothermic and explained well by e Freundlich model. Acidic pretreatment of Undaria pinnatifida enhanced its adsorption capacity for $Pb^{2+}$ , however, the reverse was observed for alkaline pretreatment. The formation of organometallic complex between $Pb^{2+}$ and some functional groups on the surface of Undaria pinnatifida was considered to be one of the main drives for adsorption. Finally the adsorbability of$ Pb^{2+}$ was examined to be rather affected by several solution features such as the coexistence of other adsorbate, the variation of ionic strength, and the concentration of complexing agent.

Preparation of Matte with Pyrite and Chalcopyrite as sulfur source and Leaching behaviour (황(黃) 원료(原料)로서 pyrite와 chalcopyrite를 사용(使用)한 matte 상(相)의 제조(製造) 및 침출특성(浸出特性))

  • Park, Kyung-Ho;Nam, Chul-Woo;Chang, Jong-Sin;Ahan, Sung-Chen;Kim, Hong-In
    • Resources Recycling
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    • v.17 no.1
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    • pp.51-58
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    • 2008
  • Artificial mattes were prepared with adding pyrite or chalcopyrite as sulfur sources with Cu-Ni-Co-Fe alloy. The major phases identified by X-ray diffraction pattern were $(FeSi)_9S_8$, $CuFeS_2$, FeS, $Co_4S_3$, $Ni_3S_2$ and $Cu_2S$ for both mattes, and the matte prepared by adding chalcopyrite showed the higher peak of $Cu_2S$ due to high content of copper. Under optimum conditions, more than 95% copper, 90% nickel and 90% cobalt were extracted into leaching solution and sulfur concentration in the mattes did not much affect the leaching efficiency of the metals. The increase of the amount of pyrite or chalcopyrite added decreased pH in leaching solution and increased the concentration of iron ion dissolved in the leaching solution and the amount of residue.

Study on Thermodynamic Properties of Sulfidization for Uranium and Rare Earth Oxides (우라늄 및 희토류(稀土流) 산화물(酸化物)의 황화반응(黃化反應)에 대한 열역학적(熱力學的) 고찰(考察))

  • Lee, Jung-Won;Lee, Jae-Won;Kang, Kweon-Ho;Park, Geun-Il
    • Resources Recycling
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    • v.21 no.1
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    • pp.66-74
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    • 2012
  • In order to evaluate the feasibility of selective sulfidization of uranium and rare-earth(RE) oxides, an analysis on thermodynamic data, such as $M-O_2-S_2$ phase stability diagram and changes of Gibbs free energy for sulfidization of uranium and rare-earth oxides were carried out. Comparing $RE-O_2-S_2$ with $U-O_2-S_2$ phase stability diagram at wide range of sulfur potential, $UO_2$ remains unreacted, while RE oxides are sulfidized. The Gibbs free energy change(${\Delta}G^{\circ}$) of sulfidization of RE oxides is lower than that of uranium oxides. Thus, the selective formation of RE sulfides is possible during sulfidization of RE and uranium oxides at lower temperature. $CS_2$ was selected as a sulfidizing agent, because it is a stronger sulfidizing agent than other agents and reacts at lower temperature.

A Study on the Formation Mechanism of Titanium Sponge in the Kroll Process (Kroll법에 의한 타이타늄 스폰지 생성기구에 관한 연구)

  • Jung, Jae-Young;Sohn, Ho-Sang
    • Resources Recycling
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    • v.26 no.5
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    • pp.54-60
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    • 2017
  • In this study, we investigated the effect of $TiCl_4$ injection time on the Kroll reaction at a given weight ratio of $TiCl_4$ and Mg. The reduction reaction was investigated by measuring the temperature change according to $TiCl_4$ injection time and observing the cross section and appearance of the Ti sponge after the reaction. The temperature increment due to Kroll reaction heat generation was found to be linearly proportional to the $TiCl_4$ feed rate. In the graph of $TiCl_4$ injection time and reduction tank temperature, initial temperature peaks were observed irrespective of the injection conditions. This is interpreted to mean a temporary interruption of reaction due to $MgCl_2$ formation after the initial Kroll reaction. In addition, when the cross section of the sponge was observed, a large amount of spherical Mg particles was observed in $MgCl_2$. We can infer that this is the process of continuously feeding the unreacted Mg surface, so that a continuous Kroll reaction takes place. The sponge appearance showed that the coalescence or growth of the Kroll reacted Ti particles can be controlled by the cooling rate.

Solvent Extraction of Rare Earth Elements (La, Ce, Pr, Nd, Sm) from Hydrochloric Acid Solutions using Cyanex 572 (염산용액에서 Cyanex 572에 의한 희토류 원소(La, Ce, Pr, Nd, Sm)의 용매추출)

  • Cho, Yeon-Chul;Kang, Myeong-Sik;Ahn, Jae-Woo;Lee, Jin-Young
    • Resources Recycling
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    • v.25 no.6
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    • pp.50-57
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    • 2016
  • This work was examined the extraction and stripping behavior of rare earths (La, Ce, Pr, Nd, Sm) from the hydrochloric acid solution by Cyanex 572 and compared to the results that of PC88A. Experimental parameters such as equilibrium pH, extractant & strip reagent concentration were observed and extraction percentage, distribution coefficient, stripping percentage and the separation factor of the adjacent element were analyzed. The $pH_{50}$ values was more higher using Cyanex 572 than that of PC88A. As the increase of the extractant concentration, the distribution coefficient of rare earth elements was increased. Stripping percentage of rare earth elementss from the Cyanex 572 was 85% to 95% and PC88A showed 80% to 87%. Separation factor of Ce/La, Ce/Pr, Pr/Nd, Nd/Sm was enhanced about 1.0-5.0 using Cyanex 572 as an extractant in mixture solution.

Solvent Extraction of Heavy Rare Earth Elements Using PC88A from Synthesis Solution of Low Concentration Rare Earth Solution (저농도 희토류 용액으로부터 PC88A를 이용한 중희토류의 용매추출 연구)

  • Ahn, Nak-Kyoon;Im, Byoungyong;Lee, Jieun;Park, Jae Ryang;Lee, Chan-Gi;Park, Kyung-Soo
    • Resources Recycling
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    • v.26 no.4
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    • pp.26-33
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    • 2017
  • The behavior on the solvent extraction of heavy rare earths (HRE) by using PC88A was confirmed to demonstrate the possibility of recovery on the HRE from industrial wastewater, which consist of low concentration rare earth. We verified the extraction behavior of the HRE through a change of equilibrium pH, extractant concentration and A/O ratio, and also confirmed the stripping behavior depending on the type of mineral acids. At equilibrium pH 1.0, extraction of rare earth (RE) was completed from 95% to 100%. In all extraction conditions, it tend to be extracted in order of high atomic number. When A/O ratio was 10/1, Yb and Tm were concentrated at the maximum and increased 6-fold and 3-fold compared to initial concentration, respectively. To confirm the stripping behavior of the RE, three mineral acids were applied to the organic phase and consequently rate of stripping was increased in order of $HNO_3$, $H_2SO_4$ and HCl.

A Study on Co-precipitation of Indium Hydroxide (In(OH)3) for the Recovery and Determination of Trace Heavy Metals (인듐 수산화물(In(OH)3)의 공동침전을 이용한 미량의 중금속 회수 및 분석방법 연구)

  • Kwon, Seul-woo;Son, Seong-Hun;Lee, Man Seung;Nam, Sang-Ho
    • Resources Recycling
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    • v.26 no.4
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    • pp.50-55
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    • 2017
  • Determination of trace elements in a sample including complicated matrix is very difficult due to the interference by the matrix. Therefore, if the trace elements can be separated from the complex sample matrix and determined, the interference effects can be reduced, and it is very helpful for the overall analysis. In this study, the analytes of trace elements were separated from the sample matrix by co-precipitation with trace elements using indium hydroxide ($In(OH)_3$), then detected by inductively coupled plasma-atomic emission spectrometer (ICP-AES). Above all, the optimal conditions for the co-precipitation of elements with indium hydroxide were experimentally established. At last, salt was analyzed by the developed analytical method. No heavy metals were not found in Shinan Jeungdo salt, but trace amounts of several heavy metals except for cadmium were found in Cheonnam Yongkwang salt.

The Fundamental Properties of Foamed Concrete as the Eco-friendly Ground Repair System for Cast in Site Using the CSA (CSA를 사용한 친환경 지반보수용 현장 기포콘크리트의 기초 특성 검토)

  • Woo, Yang-Yi;Park, Keun-Bae;Ma, Young;Song, Hun-Young
    • Resources Recycling
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    • v.29 no.1
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    • pp.53-61
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    • 2020
  • This study aimed to develop a foam concrete material for a ground repair system that has low strength and low fluidity by using an eco-friendly binder, which substitutes industrial by-products for more than 90% of cement. Basic properties were evaluated after substituting a small amount of calcium sulfo aluminate (CSA) for the binder to improve the sinking depth rate and volume change, commonly found when it had a large amount of industrial by-products. The substitution rates of CSA for the eco-friendly binder used for the foam concrete were 2.5, 5, and 10%. Fresh properties, hardened properties, pore structure, and hydrates were analyzed. Experimental results showed that using only 2.5% of CSA could improve the deep sinking depth which occurred when using an eco-friendly binder. As a result, the weight difference between the upper, middle, and lower parts of cast specimens was improved even after being hardened. The addition of CSA also contributed to the formation of small, uniformly sized closed pores and improved initial strength. However, when the proportion of CSA increased, the long-term strength decreased. However, it satisfied the target strength when 5% or less of CSA was used. The results of this study revealed that it was possible to manufacture foam concrete with low strength and high fluidity for repairing ground satisfying target qualities by adding 2.5% of CSA to the eco-friendly binder containing a large amount of industrial by-products.