• Corrosion Science and Technology
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• 제16권3호
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• pp.91-99
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• 2017

The objective of this work was to develop efficient synergistic inhibitor combinations comprising sodium nitrite ($NaNO_2$) and an inhibitor-blend code named (SN-50), keeping in view of their application in industrial cooling water systems. The electrochemical characteristics of the carbon steel working electrode in simulated cooling water (SCW), without and with the addition of different combinations of the inhibitors, were investigated using electrochemical impedance spectroscopy (EIS), open circuit potential (OCP). The electrode surface changes were followed by visual characterization methods. It was demonstrated in this study that all the combinations of the inhibitors exhibited synergistic benefit and higher inhibition efficiencies than did either of the individual inhibitors. The addition of SN-50 inhibitor to the SCW shifted the OCP to more anodic values and increased the polarization resistance ($R_p$) values of carbon steel at all applied concentrations. The higher the applied sodium nitrite concentration (in the protection concentration range), the higher the obtained $R_p$ values and the inhibition efficiency improved by increasing the inhibitor concentration.

• 태양에너지
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• 제9권1호
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• pp.70-77
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• 1989

Sodium pyrophosphate that melting point is $79-80^{\circ}C$ have been Studied on heat storage and heat discharge. In heat storage process, sodium pyrophosphate was kept up initial temperature $50^{\circ}C,\;60^{\circ}C,\;70^{\circ}C$ which melt by heated water at temperature $85^{\circ}C,\;90^{\circ}C,\;95^{\circ}C$. In heat discharge process, initial temperature of sodium pyrophosphate was maintained at temperature $85^{\circ}C,\;90^{\circ}C,\;95^{\circ}C$ which varied cooling temperature $50^{\circ}C,\;60^{\circ}C,\;70^{\circ}C$. The experiment has been reached conclusions as follows. 1) Heat transfer properties of phase change material is controlled by conduction during heating and cooling process. 2) The temperature increased rapidly at initial stage and transient region increase slowly because of characteristic of latent heat. 3) The lower cooling water temperature is the less the time that get to thermal equivalent state take during discharge process. 4) The higher cooling water temperature is the less temperature difference between top and bottom in P.C.M during discharge process.

• Asian-Australasian Journal of Animal Sciences
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• 제7권2호
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• pp.159-164
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• 1994

Two studies were conducted using 40 cross-bred bulls to study the effect of chopping, moistening with water or common salt solution on the nutritive value of rice straw (variety BG-400). Moistening with water did not significantly effect digestibility or intake of rice straw. As compared to straw fed in the long form, chopping did not significantly influence intake (2.33 vs 1.97kg $100kgBW^{-1}day^{-1}$, respectively), but significantly (p<0.05) decreased the digestibility (41.6 vs 37.4%) and intake of digestible dry matter (0.99 vs 0.74kg $100kgBW^{-1}day^{-1}$). Rice straw moistened with 2 or 4% common sea salt solution and directly fed to animals (Exp. 1) did not significantly effect its digestibility (43.9 and 43.1%, respectively) or intake (2.66 or 2.59kg $100kgBW^{-1}day^{-1}$, respectively), but over night storing of 2% salt solution sprayed straw (Exp. 2) significantly reduced its digestibility (33.6%). The latter is difficult to explain because the sodium concentration (mg/g straw dry matter) was lower than 4% salt solution treatment used in experiment 1 (3.30 vs 5.22). It is concluded that chopping, moistening with water or NaCl salt solution did not significantly improve the nutritive value of rice straw.

• Archives of Pharmacal Research
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• 제19권1호
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• pp.30-35
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• 1996

Poly(l-lactic acid)(PLLA) microspheres loaded with ampicillin sodium (AMP-Na_, .betha.-lactam antibiotic, were prepared by a w/o/w multiple emulsion-solvent evaporation method. The amounts of each component in three phases (inner water phase, organic phase, and outer water phase) wre carefully examined in the preparation of PLLA microspheres. The stirring rate, another preparation parameter, was also investigated for study on the effect of mechanical stress on the drug loading and morphology of PLLA microspheres. Most of the preparation parameters had a great influence on the drug loading, surface morphology and size distribution of PLLA microspheres. PLLA microspheres with 15.89 w/w% drug loading were subjected to the in vitro release experimet. The release of ampicillin sodium was constant at a rate of 1.68 $mug/ml/day$ per 1 mg of microspheres for 18 days initial burst effect.

• Environmental Engineering Research
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• 제11권5호
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• pp.266-276
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• 2006

Commonly, the flocculant is dissolved in process or recycle water in industrial plant which has many ionic materials. Therefore, the polymer degradation in aqueous solution by chemical, mechanical or bacteriological may occur, sometimes rapidly. Even if the same flocculant is dissolved, the flocculation characteristics and the properties of dissolving polymer varied with the kind of dissolving water. In this study, we try to estimate the interaction between flocculants and ionic materials in dissolving water using self inversing emulsion polymer; polyacrylamide-co-trimethyl ammonium ethyl acrylate chloride flocculants which have varying molecular weights and structures at a several conditions. The polymeric flocculant is dissolved in artificial dissolving water with Potassium Chloride (PC), Calcium Chloride anhydrous (CC), Potassium Hydroxide (PH), Sodium Chloride (SC), Sodium Bromate (SB) and Iron (II) Sulfate Heptahydrate (IS) as ionic sources. Experimental results indicate that the cationic and anionic ions in dissolving water induce the hydrolysis, degradation of cationic functional group and uncoiling of polymeric flocculants, therefore, the flocculation efficiency decreased by undesired polymer. According that result, it is important to estimate not only its structures and physical properties but also the qualities of dissolving water to optimize the efficiency.

• 한국응용과학기술학회지
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• 제13권3호
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• pp.83-94
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• 1996

EMA-co-DAMA were synthesized from 2-diethylaminoethyl metacrylate and ethylhexyl metacrylate in acrylmonomer. To facilitate water emulsification, acrylic copolymer was cationized by acetic acid to produce acetated acrylic copolymer. The structures of the synthesized copolymer and acetated copolymers were confirmed by IR, NMR, and molecular weight was measure by GPC, and C.H.N elemental analysis. Acetated acrylic copolymers were perfectly emulsified in water and showed increased emulsion stability. Polymer dispersion for cement modifier[(PDCM-PED) water proof agent of cement for concrete in building construction] was prepared by blending of the guaternized acrylic copolymer syndisized above, sodium silicate, sodium gluconate and oleic acid emulsion. The result with prepared polymer dispersion of cement modifier was examined, and it was found that excellent waterprooffing effect ; Water permeability ratio is 0.50 under the water pressure of $100g/cm^2$ and 0.60 under $3kg/cm^2$, and water absorption ratio is $0.42{\sim}0.50$ and $1.0{\sim}1.02$ compressive strength ratio at mixed of water/PDCM-PED is 50 times.

• 한국잠사곤충학회지
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• 제36권1호
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• pp.37-43
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• 1994

네 종의 서로 다른 인산염을 견정련 보조제로 사용한 경우에 있어서, 정련용수 중 금속이온의 봉쇄, 정련용액의 pH 변화, 그리고 연감효과에 대하여 검토하고 아래와 같은 결과를 얻었다. 1. 칼슘경도성분에 대한 봉쇄효과는 TSPP와 SPD가 높은 봉쇄효과를 나타내었으며, SPM과 SHP는 비교적 낮은 봉쇄효과를 보였다. 2. 철성분에 대한 봉쇄효과는 SHP와 TSPP가 우수한 봉쇄능력이 있었다. 3. 4종의 인산염 중 TSPP와 pH값이 가장 높지만 비누에 비해서는 낮다. 4. 정련속의 pH값은 인산염의 종류에 따라 많은 차이가 있었으나 pH값이 클수록 정련효과가 크게 나타났다.

• 한국포장학회지
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• 제5권1호
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• pp.6-12
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• 1999

본 실험은 라면 스프 포장재에 대한 가식성 필름의 응용성을 조사하였다. 기본 실험으로서는 라면 스프의 등온흡습곡선 및 BET 단분자막 수분함량을 조사하였으며, 응용성 실험으로서는 가식성 필름의 인장강도, 신장률, 수분 투과도 및 용해도를 대하여 조사하였다. 가식성 필름으로서는 methylcellulose, sodium caseinate 및 K-carrageenan을 사용하였으며, 가소제로서는 glycerol과 polyethylene glycol (MW 400)을 사용하였다. 인장강도의 경우, methylcellulose 필름의 수치가 68.56 MPa로 가장 크게 나타났으며, sodium caseinate 필름이 가장 낮은 수치인 7.11 MPa로 나타났다. 신장률에 대한 실험 결과, sodium caseinate 필름이 가장 높은 수치인 115.41 %를 나타냈으며, methylcellulose 및 K-carrageenan 필름은 각각 23.79% 및 0.60%로 나타났다. 상대습도 50% - 70%사이에서 methylcellulose와 sodium caseinate 및 K-carrageenan 필름의 측정된 수분 투과도 값의 범위는 각각 $0.25-0.38ng\;m/m^2{\cdot}sec{\cdot}Pa$와 $0.62-0.84ng{\cdot}m/m^2{\cdot}sec{\cdot}Pa$ 및 $0.31-0.55ng{\cdot}m/m^2{\cdot}sec{\cdot}Pa$로 나타났다. 가식성 필름의 용해도에 대해서는 sodium caseinate film의 경우 뜨거운 물에 대한 높은 용해성을 나타내어 5초 이내에 이 필름은 물에 용해되었으며, K-carrageenan film은 높은 팽윤율을 나타내어 150초 이후에 필름의 붕괴 현상이 일어났다. Methylcellulose film의 경우는 물에 대한 용해도가 떨어지는 것으로 나타났다.

• 한국식품저장유통학회지
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• 제24권6호
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• pp.771-777
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• 2017

된장은 대두를 주원료로 하는 한국의 대표적인 전통발효 식품임이나, 국민건강영양조사에서 고나트륨을 가지는 식품군에 분류되었다. 각종 질병의 원인이 될 수 있는 나트륨 과다섭취에 대한 저나트륨 된장의 개발이 필요한 실정으로, 품질에 크게 영향이 없이도 나트륨 함량이 적은 장류의 개발은 지속적으로 연구되어야 하는 과제이다. 따라서 본 연구에서는 나트륨 함량을 12.5%-45%까지 저감하도록 실험을 설계하여 적용하여 된장 담금을 진행하였으며, 그 품질적 특성을 분석하고자 하였다. 나트륨의 저감화가 된장의 관능적 품질에 영향을 미치는지 pH, 염도 및 수분, 나트륨함량, 색도, 아미노산성 질소함량, 유리아미노산, 구성아미노산조성을 평가하여, 그 특성을 비교 분석하였다. 나트륨의 저감화는 pH와 수분, 염도에 크게 영향을 미치지 않았으며, 대조구와 같은 범위에서의 품질을 유지하였다. 나트륨함량은 실제로 비례적으로 감소되었으며, 아미노산성 질소는 500 mg%수준이었다. 대량으로 된장업체에서 제조한 25% 저염된 된장의 대체소재를 사용하는 것은 최종 된장의 나트륨함량을 줄이면서도 된장의 품질에 큰 영향을 미치지 않을 것으로 사료된다.

• 한국환경보건학회지
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• 제48권3호
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• pp.167-175
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• 2022

Background: Disinfection is essential to provide drinking water from a water source. The disinfection process mainly consists of the use of chlorine and ozone, but when chlorine is used as a disinfectant, the problem of disinfection by-products arises. In order to resolve the issue of disinfection by-products, electro-chlorination technology that produces chlorine-based disinfectants from salt water through electrochemical principles should be applied. Objectives: This study surveys the possibility of optimally producing active chlorine from synthetic NaCl solutions using an electro-chlorination system through RSM. Methods: Response surface methodology (RSM) has been used for modeling and optimizing a variety of water and wastewater treatment processes. This study surveys the possibility of optimally producing active chlorine from synthetic saline solutions using electrolysis through RSM. Various operating parameters, such as distance of electrodes, sodium chloride concentration, electrical potential, and electrolysis time were evaluated. Results: Various operating parameters, such as distance of electrodes, sodium chloride concentration, electrical potential, and electrolysis time were evaluated. A central composite design (CCD) was applied to determine the optimal experimental factors for chlorine production. Conclusions: The concentration of the synthetic NaCl solution and the distance between electrodes had the greatest influence on the generation of hypochlorite disinfectant. The closer the distance between the electrodes and the higher the concentration of the synthetic NaCl solution, the more hypochlorous acid disinfectant was produced.