• 한국재료학회지
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• 제8권2호
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• pp.126-130
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• 1998

카올린을 용해시킨 황산용액을 에탄올에 주입함으로써 알루미늄황산염의 침전물, $AI_{2}(SO_{4})_{3}\cdot18H_{2}O$을 제조하고, 그것의 열분해거동을 검토하였다. 합성된 고순도의 침전물은 약 $2\mu\textrm{m}$크기의 판상형태의 입자들로 구성되어져 있었다. 에탄올속으로 카올린을 용해시킨 황산용액의 주입속도를 증가시킴에 따라서 생성된 침전물의 결정사 크기는 감소하였다. 침전물의 탄수 및 탄황산에 대한 겉보기 활성화에너지는 각각 $11.9Kcal mol^{-1}$ 과 $48.2kcal mol^{-1}$ 이었다.

• Carbon letters
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• 제7권4호
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• pp.249-258
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• 2006

Treatment of water hyacinth with sulphuric acid produces carbonaceous materials that have been used to remove Cu(II) and Cd (II) ions from aqueous solutions. Untreated water hyacinth was also used for the subject of comparison. The textural properties of the carbonaceous materials were determined from nitrogen adsorption at 77 K. The optimum pH for the sorption of Cu (II) and Cd (II) ions on the investigated sorbents was determined. Dynamic adsorption measurements have been taken at 298 K whereas equilibrium measurements were carried out at 298, 313 and 323 K. The adsorption of nitrogen at 77 K on the untreated sample was too low and the surface areas of the treated samples 2, 3 and 4 were found between $70-208\;m^2/g$. The total pore volumes of these samples which were determined for the carbonaceous materials investigated were found to be 0.076-0.140 ml/g. The kinetic adsorption data of Cu (II) and Cd(II) were applicable to both pseudo - first and pseudo-second order but fit more the latter order. The equilibrium adsorption data were found to fit Freundlich and Langmiur equations. The values of DG, DH and DS are all negative indicating the feasibility and the spontaneous nature of the sorption of Cu (II) and Cd (II) ions by the sorbents investigated.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2000년도 추계학술발표대회
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• pp.119-127
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• 2000

The development and performance of a competitive indirect immunoassay for the quantitative measurement of polychlorinated biphenyl compounds in insulating oils is presented. Reagent preparation and the assay characterisation, optimisation and validation steps are described. The dynamic range of the assay for Aroclors 1254 and 1260 in methanol was $50-800 {\mu}g\;ml^{-1}$ with $50\%$ signal inhibition values of 217 and $ 212 {\mu}g\;ml^{-1}$ respectively. Impending legislation in the UK is likely to decree that oils containing $ >50 {\mu}g\;ml^{-1}$ PCB be considered contaminated. Assay sensitivity increased with the degree of PCB chlorination. The assay of structurally related compounds of environmental concern yielded cross-reactivity values of under $0.6\%$. The immunoassay proved reliable for the analysis of transformer oils containing $>70{\mu}g\;ml^{-1}$ PCB, but over-estimated PCB levels in oils containing $<20{\mu}g\;ml^{-1}$ of the analyte with the oils requiring pre-treatment using either solid-phase extraction techniques or washing with KOH-ethanol/sulphuric acid to remove matrix interferents. The analytical performance of the assay was compared against a commercially available semi-quantitative immunoassay kit for PCBs in soil and water.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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• pp.239-242
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• 2009

As the high-rise building increase due to the gravitation of population to big cities recently, it requires high quality and high performance of Concrete. As a result, people are keenly interested in Meta-kaolin as new admixture favorable from an economic perspective, which has strength and endurance with admixture at the same level like Silica-fume. Accordingly, as to Meta-kaolin, this study was to set by three levels like domestic one, foreign one, and Silica-fume, the water-binding material ratio 25%, and four level substitute like 0, 10, 20, and 30(%) in order to compare and analyze the quality durability of high-concrete according to the substitute of Meta-kaolin applicable with replacement of Silica-fume. As a result of performing experiment it was found that when water-binding material ratio increases, resistance of neutralization, carbonation, salt damage and sulfate decrease, and when replacement ratio of mineral admixture increases, depth of accelerating carbonation gets greater. Also, the combination of SF and MK-B favored resistance to chloride ion penetration better than MK-A, and it was found that when replacement ratio of binding material increases, the resistance to sulphuric acid increases. Therefore, based on this study, it was understood that meta-kaolin is useable in replacement of silicafume.

• Advances in Energy Research
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• 제7권2호
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• pp.147-166
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• 2020

Industrial cooling towers are often ageing infrastructure that is expensive to maintain and operate. A novel approach is introduced in which a heat pump circuit is incorporated to reduce the load upon the towers by extracting low-grade energy from the stream sent to the towers and repurposing in on-site processing operations. To demonstrate the concept, a model was constructed, which uses industrial data on cooling towers linked to a smelter's sulphuric acid plant, to allow direct economic and environmental impact comparison between different heat recovery and repurposing scenarios. The model's results showed that implementing a heat pump system would significantly decrease annual operating costs and achieve a payback period of 3 years. In addition, overall CO₂ emissions could be reduced by 42% (430,000 kg/year) and a 5% heat load reduction on the cooling towers achieved. The concept is significant as the outcomes introduce a new way for energy intensive industrial sectors, such as mineral processing, to reduce energy consumption and improve long-term sustainable performance.

• Membrane and Water Treatment
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• 제10권5호
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• pp.373-379
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• 2019

One of the real issues of the recent years is water contamination because of harmful synthetic dyes. Liquid Membranes (LM) resemble a promising alternative to the current separation processes, demonstrating various points of interest as far as effectiveness, selectivity, and operational expenses. The improvement of various Liquid Membranes designs has been a matter of examination by few researchers, particularly for the expulsion of dyes from aqueous solutions. The choice of organic surfactants plays an essential role in the efficiency of the dye removal. In LM design, the most significant step towards productivity is the decision of the surfactant type and its concentration. Liquid emulsion membrane (LEM) was used to remove safranin from aqueous solutions in which the emulsion was made with the help of D2EHPA as carrier, kerosene was used as a diluent and Span 80 (Sorbiton monooleate) was used as an emulsifying agent or surfactant. Various sorts of internal stages were utilized, to be specific sulphuric acid and sodium hydroxide. The impact of parameters influencing extraction efficiency such as pH of feed solution, concentrations of surfactant and emulsifying agent in membrane phase, volume ratio of internal phase to membrane phase, internal phase concentration, agitation speed and time of extraction were analyzed.

• 대한약침학회지
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• 제25권1호
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• pp.37-45
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• 2022

Objectives: The quorum-sensing-inhibitory and anti-biofilm activities of the methanol extract of E. globulus leaves were determined against clinically isolated multidrug-resistant Pseudomonas aeruginosa. Methods: The preliminary anti-quorum-sensing (AQS) activity of eucalyptus was investigated against a biosensor strain Chromobacterium violaceum ATCC 12472 (CV12472) by using the agar well diffusion method. The effect of sub-minimum inhibitory concentrations (sub-MICs) of the methanol extract of eucalyptus on different quorum-sensing-regulated virulence factors, such as swarming motility, pyocyanin pigment, exopolysaccharide (EPS), and biofilm formation, against clinical isolates (CIs 2, 3, and 4) and reference PA01 of Pseudomonas aeruginosa were determined using the swarm diameter (mm)-measurement method, chloroform extraction method, phenol (5%)-sulphuric acid (concentrated) method, and the microtiter plate assay respectively, and the inhibition (%) in formation were calculated. Results: The preliminary AQS activity (violacein pigment inhibition) of eucalyptus was confirmed against Chromobacterium violaceum ATCC 12472 (CV12472). The eucalyptus extract also showed concentration-dependent inhibition (%) of swarming motility, pyocyanin pigment, EPS, and biofilm formation in different CIs and PA01 of P. aeruginosa. Conclusion: Our results revealed the effectiveness of the E. globulus extract for the regulation of quorum-sensing-dependent virulence factors and biofilm formation at a reduced dose (sub-MICs) and suggest that E. globulus may be a therapeutic agent for curing and controlling bacterial infection and thereby reducing the possibility of resistance development in pathogenic strains.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 춘계 학술기술논문발표대회 논문집
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• pp.211-214
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• 2005

Recently, Deterioration of the concrete sewer concrete structures by biochemical corrosion has been issued and a development of the inhibition system of corrosion that has been demanded. The sulfuric acid may react with the hardened cement paste and originate expansive products which can induce swelling and breakless of concrete. Also, a sulphuric acid reacts with calcium hydroxide to from $CaSO_4\;\cdot\;2H_2O$. This reaction accounts for consumption of the calcium hydroxide present in hardened cement paste. In this study, To present from biochemical corrosion of the sewer repair mortar that was spread with liquefied antibiotic and then its experimental properties were experimentally investigated and to estimate the effect of absorbed condition of restorative mortar, the number of coating times and coating contents with antibiotic on the durability properties of restorative mortar spread with antibiotics. Also, testing items such as carbonation depth, choloride ion penetration depth and chemical resistance was tested to estimate the durability properties in third study. In results, the novellus bacillus inhabiting in sewer concrete structures was restrained by antibiotics developed in this study. And carbonation depth, choloride ion penetration depth and chemical resistance of restorative mortar spread with antibiotics was superior to that of plain mortar.

• 한국수소및신에너지학회논문집
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• 제20권4호
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• pp.300-308
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• 2009

In a pursuit of the development of alternative mobile power sources with a high energy density, a planar and air-breathing PEMFCs with a new type of hydrogen cartridge which uses onsite $H_2$ generated from sodium borohydride ($NaBH_4$) hydrolysis have been investigated for use in advanced power systems. Two types of $H_2$ generation through $NaBH_4$ hydrolysis are available: (1) using organic acids such as sulphuric acid, malic acid, and sodium hydrogen carbonate in aqueous solution with solid $NaBH_4$ and (2) using solid selected catalysts such as Pt, Ru, CoB into the stabilized alkaline $NaBH_4$ solution. It might therefore be relevant at this stage to evaluate the relative competitiveness of the two methods mentioned above. The effects of flow rate of stabilized $NaBH_4$ solution, MEA (Membrane Electrode Assembly) improvement, and type and flow control of the catalytic acidic solution have been studied and the cell performances of the planar, air-breathing PEMFCs using $NaBH_4$ has been measured from aspects of power density, fuel efficiency, energy density, and fast response of cell. In our experiments, planar, air-breathing PEMFCs using $NaBH_4$ achieved to maximum power density of 128mW/$cm^2$ at 0.7V and energy efficiency of 46% and has many advantages such as low operating temperature, sustained operation at a high power density, compactness, the potential for low cost and volume, long stack life, fast star-up and suitability for discontinuous operation.

• The Korean Journal of Ecology
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• 제16권4호
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• pp.409-416
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• 1993

인공산성빗물에 대두(Glycine max), 청갈참 (Quercus aliena var. pellucida) 및 리기다소나무(Pinus rigida)에 살포한 후 연속적으로 일정량을 받아서 이온량을 정량하였다. 모든 잎에서 세탈된 이온의 양은 초기에 많았으나 시간이 지날수록 감소하였으며, 세탈되는 이온량은 빗물의 pH가 낮을수록 세탈되는 이온량은 많았다. 총 세탈된 K의 양은 정상빗물(pH5.6) 보다 pH 4.0의 빗물에서1.04~1.46배, pH 3.5의 빗물에서 1.09~1.58배, 그리고 pH 3.0의 빗물에서 1.24~2.03배 만큼 많았다. 총 세탈된 Ca량은 정상빗물보다 ph 4.0의 빗물에서 1.23~1.47배, pH 3.5 빗물에서 1.50~1.92배, 그리고 pH3.0의 빗물에서 2.45~3.30배 만큼 많았다. 총 세탈액 속의 Ca/K의 비는 청갈참에서 1.10~2.91, 리기다소나무에서 1.68~2.98, 그리고 대두에서 0.66~0.91이었다. 조사된 모든 식물에서 빗물의 pH가 낮아질수록 Ca/K 비율이 커졌다. 산성빗물처리 후의 식물체를 분석한 결과 이온세탈 효과는 pH3.0 처리구에서만 유일하게 나타났다.