• Tribology and Lubricants
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• 제11권5호
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• pp.1-9
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• 1995

The mechanism of various spherical particles formation from wide range of tribo-systerns is suggested and deduced by the action of micro-explosion on the basis of the thermally-activated wear theory, in which the flash temperature at contact could be reached clearly upto the material molten temperature due to the secondary activation energy from the exothermic reactions involving lubricant thermo-decomposition, metals oxidation, hydrogen reactions and other possible complex thermo-reactions at the contacts. Various shapes of spherical particles generated from the tribosystem can be explained by the toroidal action of micro-explosion accompanied with the complex thermo-chemical reactions at the contact surfaces or sub-surfaces.

• Carbon letters
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• 제3권3호
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• pp.146-151
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• 2002

Activated carbon fibers were prepared from the petroleum isotropic pitch and organometallic compounds. The metalsvwere dispersed uniformly in the ACFs. The specific surface area and pore size distributions of metal containing ACFsvwere measured. The mesopores of ACFs were developed by Co, Ni, and Mn metals addition and the catalytic reactivityvof ACFs'SOx removal was increased by adding Ni and Pd metals. It was found that the mesopores did not work forvthe improvement of catalytic reactivity of ACFs' SOx removal with the blank experiment using the metal removedvACFs.

• 한국건설순환자원학회논문집
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• 제4권3호
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• pp.276-283
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• 2016

레드머드는 보오크사이트 원광석에서 생산되는 알루미나의 선광과정에서 발생되는 무기질 부산물이다. 인 레드머드를 활용하고자 하는 연구가 국내에서 이루어지고 있다. 강알카리성의 레드머드를 건설산업용 촉진제로서 활용하고자 하는 연구로서 알칼리활성화 슬래그-레드머드 시멘트가 국내외적으로 발표되고 있다. 본 논문은 순환골재 대체율에 따른 알칼리활성화 슬래그-레드머드 건식 흙포장재의 최적함수율, 압축강도, 흡수율, 백화발생 특성에 대하여 비교 검토하였다. 그 결과 순환골재 대체율이 증가할수록 알칼리활성화 슬래그-레드머드 흙포장재의 최적 함수비, 물흡수계수, 백화면적은 증가하고 압축강도는 감소하였다.

• 대한화학회지
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• 제30권1호
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• pp.105-108
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• 1986

초음파(50KHz)가 상온 상압하에서 히드라진 철 활성탄을 이용한 방향족 니트로기를 방향족 아미노기로의 환원반응을 크게 가속시켜 3시간만에 100% 전환율을 얻을 수 있었다. 활성탄은 탈색이나 반응성이 큰 물질의 분말을 섞는데 사용되어 왔으나 히드라진 철을 이용한 방향족 니트로기의 환원반응에서는 활성탄 없이는 반응이 전혀 일어나지 않으며 활성탄의 증가에 따라 환원율이 높아지는 결과를 얻었다.

• Carbon letters
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• 제9권3호
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• pp.181-187
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• 2008

Batch sorption experiments were carried out for the removal of metylene blue from its aqueous solution using $H_3PO_4$ activated Acacia arabica carbon (AAC). The prepared activated carbon was characterized and was found as an effective adsorbent material. The operating variables studied were initial metylene blue concentration, AAC concentration and solution pH. AAC activated carbon posses a maximum sorption capacity for the range of initial dye concentrations studied (60~100 mg $L^{-1}$). The sorption kinetics were analyzed using reversible first order kinetics, second order, reversible first order, pseudo-first order, and pseudo-second order model. The sorption data tend to fit very well in pseudo-second order model for the entire sorption time. The average pseudo-second order rate constant, $K_{II}$ and regression coefficient value were determined to be 0.0174 mg $g^{-1}$ $min^{-1}$ and 0.9977. The biosorption process also fit well to reversible I order kinetics with a regression coefficient of 0.9878.

• Journal of the Korean Wood Science and Technology
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• 제52권2호
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• pp.118-133
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• 2024

The sapwood portion of fast-growing teak is mostly ignored due to its inferior quality. One of the possibilities for utilizing sapwood waste is to convert it into activated carbon that has good adsorption capabilities. The raw materials used in this research were sapwood of 14-year-old fast-growing teak sapwood (FTS) waste, which was taken from three trees from community forests in Wonosari, Gunungkidul, Yogyakarta Special Region. FTS waste was taken from the bottom of the tree up to a height of 1.3 m. The activation process is conducted with an activation temperature of 750℃, 850℃, and 950℃. The heating duration consists of three variations: 30 min, 60 min, and 90 min. The quality evaluation parameters of activated carbon include yield, moisture content, volatile matter content, ash content, fixed carbon content, adsorption capacity of benzene, adsorption capacity of methylene blue, and adsorption capacity of iodine. The results showed that the activated carbon produced had the following quality parameters: yield of 75.61%; moisture content of 1.27%; volatile matter content of 9.98%; ash content of 5.43%; fixed carbon content of 84.58%; benzene absorption capacity of 8.58%; methylene blue absorption capacity of 87.73 mg/g; and iodine adsorption capacity of 948.19 mg/g. It can be concluded that activated carbon from FTS waste has good iodine adsorption, which fulfilled the SNI 06-3730-1995 quality standard. Due to the iodine adsorption ability of FTS waste activated carbon, the conversion of FTS waste to activated carbon is categorized as a potential method to increase the value of this material.

• 환경위생공학
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• 제14권1호
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• pp.24-30
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• 1999

A biological filter for treatment of toluene among volatile organic compounds was studied. The investigation was conducted using specially built stainless steel columns packed with granular activated carbon and cold for removal of toluene. The G.A. and mold as filter material was also coated with Pseudomonas putida microorganisms.The biofilter unit was operated in the condition of moisture content vairation at gas loading rate of 12.5 l/min. Gaseous toluene taken from tedlar bag was analyzed by the use of G.C equipped with F.I.d detector. The removal efficiency of gaseous toluene was 95% at average inlet concentration of 950 ppm during bio-degradation operating condition. Effective removal efficiency was obtained with moisture content 27.5% at activated carbon and 32% at mold in this study. The effective operating condition were obtained with pH 6-8, temperature 28-42℃ for microbial degradation at gas loading rate of 12.5 l/min in packed material.

• 환경위생공학
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• 제13권2호
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• pp.88-94
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• 1998

This study was investigated the application of biofiltration using cometabolic process to remediate gaseous toluene that are highly recalcitrant to adsorption, absorption and biodegradation. The investigation was conducted using specially built steel columns packed with granular activated carbon for removal of toluene and G.A.C was also coated with Pseudomonas putida microorganisms by addition of KH$_{2}$PO$_{4}$. The biofilter unit was operated in the condition of dry and 27.5% moisture content at gas loading rate of 12.5 l/min. Gaseous toluene taken from tedlar bag was analyzed by the use of G.C. equipped with F.I.D. detector. The removal efficiency of gaseous toluene was 85% at average inlet concentration of 970 ppm during dry operating condition. For gaseous toluene, 91% removal efficient was obtained at the filter material with moisture content and 97% removal efficiency was obtained with Pseudomonas putida microorganisms at gas loading rate of 12.5 l/min.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.186-189
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• 2004

Although magnesium has high potential for structural material due to the lightweight and high specific strength, the structural application has been limited by the low ductility at room temperature. The reason of the poor ductility is few activated slip systems of magnesium (HCP structure) during deformation. As temperature increases, however, additional non-basal slip systems are incorporated to exhibit higher ductility comparable to aluminum. In the present study, a series of tensile tests of Mg-Al alloy has been carried out to study deformation behavior with temperature variation. Analysis of load relaxation test results based on internal variable approach gave information about relationship between the micromechanical character and corresponding deformation behavior of magnesium. Especially, the material parameter, p representing dislocation permeability through barriers was altered from 0.1 to 0.15 as the non-basal slip systems were activated at high temperature.

• 소성∙가공
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• 제13권6호
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• pp.535-539
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• 2004

Although magnesium has high potential for structural material due to the lightweight and high specific strength, the structural application has been limited by the low ductility at room temperature. The reason of the poor ductility is few activated slip systems of magnesium (HCP structure) during deformation. As temperature increases, however, additional non-basal slip systems are incorporated to exhibit higher ductility comparable to aluminum. In the present study, a series of tensile tests of Mg-Al alloy has been carried out to study deformation behavior with temperature variation. Analysis of load relaxation test results based on internal variable approach gave information about relationship between the micromechanical character and corresponding deformation behavior of magnesium. Especially, the material parameter, p representing dislocation permeability through barriers was altered from 0.1 to 0.15 as the non-basal slip systems were activated at high temperature.