• Applied Chemistry for Engineering
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• 제4권2호
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• pp.365-372
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• 1993

$CO_2$ methanation was performed over Ni supported on cation-exchanged Y zeolites under atmospheric pressure at $250{\sim}550^{\circ}C$ and $H_2/CO_2$ mole ratio of 4. Adsorption strength between carbon dioxide and nickel was found to be Influenced by the cation exchanged in the zeolite. TPD(Temperature-programmed desorption) results show that the adsorption strength decreases in the order of Ni/NaY>Ni/MaY>Ni/HY. TPSR(Temperature-programmed surface reaction) results indicate that enhanced methanation activity is obtained when the adsorption strength between carbon dioxide and nickel is stroing. As the reduction temperature increases, the methantion activity of the catalyst increase. From this result the larger size nickel particle seems advantageous for $CO_2$ methanation reaction. The maximum activity is obtained when nickel loading is 3.3wt%. Carbon monoxide is produced as a by-product throughout the reaction temperature range, and as the contact time increases, the selectivity to methane increases and the selectivity to carbon monoxide decreases steadily. Thus methane seems to be produced from $CO_2$ via CO as an intermediate species. In the temperature range of $410{\sim}450^{\circ}C$, the methane production rate is found to be dependent on the orders of 3.3~-0.5 and 1.4~3.6 with respect to $CO_2$ and $H_2$ partial pressures, respectively. This clearly shows that $CO_2$ and $H_2$ are competing for adsorption sites and as the reaction temperature increases, it becomes increasingly difficult for $H_2$ to be adsorbed on the catalyst surface.

• Composites Research
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• 제25권6호
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• pp.198-204
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• 2012

The objective of this study is to improve the mechanical properties in abaca fabric/epoxy composites produced using a VARTM process. The mechanical properties were improved by increasing the surface roughness of the fabric through plasma polymerization and improving the interfacial adhesion between the epoxy and the fabric through changing its hydrophilic properties to the hydrophobic properties. Plasma polymerization at atmospheric pressure and room temperature was used, and the optimal polymerization time to improve the mechanical properties was investigated. NaOH treatment on the fabric was also carried out for the comparison. The composite fabricated using the fabric polymerized for 10 seconds shows the highest tensile strength compared to that of none-polymerized or NaOH treated. Plasma polymerization for more than 20 seconds exhibits decrease in the tensile strength. As a result, the plasma polymerization for more than 20 seconds may have caused some damages on the surface of the fabrics. Also, the hydrophilic abaca represents a tendency of presenting the hydrophobic properties in absorption and sedimentation tests.

• Composites Research
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• 제26권3호
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• pp.170-174
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• 2013

Atmospheric glow plasma polymerization was applied to wood powder before fabricating polypropylene (PP) matrix composites. Seven different types of monomers (Oxygen, Benzene, CH4, Acrylic-acid, Hexafluoroethane, Trifluorotolune, Hexamethyl-disiloxane) were analyzed to determine the most suitable precursor for plasma polymerization. The surface energy was calculated from measured contact angle about each monomer on PP. Hexamethyl-disiloxane (HMDSO) had a highest surface energy and is selected as the most suitable monomer. Wood powder and polypropylene were mixed as pellets by twin screw extruder and then 50 wt% wood powder/PP composites were produced by an injection machine. Tensile strength and Flexural strength have improved by 7.59% and 12.43% at the maximum respectively. SEM (Scanning Electron Microscope) observation on the fracture surface revealed that the plasma polymerization have improved the interfacial bonding and the mechanical properties of the composites.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 한국염색가공학회 2011년도 제45차 학술발표회
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• pp.51-51
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• 2011

Acetate 섬유는 고감성 제품의 대표적 핵심소재로서 실크와 같은 우아한 광택과 청량감을 주어 고가의 의류제품으로 사용되지만 편직 및 염색가공 공정이 까다롭고 비교적 저분자량의 분산염료로 염색되어 내열성, 염색견뢰도 및 물에 대한 형태안정성이 떨어진다. 특히, Acetate 편직물은 이태리나 일본 등 섬유선진국에서도 제조가 까다로운 기술적 난이도가 매우 높은 제품군이다. 반면 Tri-Acetate는 Acetate의 장점을 가지면서 내열성, 내세탁성, 원상회복력(resilience)등이 우수하여 기존 Acetate 시장의 고급제품 용도로의 전개가 가능할 뿐만 아니라 PET 등의 물성 및 형태가 다른 복수의 소재성분을 직물 사이에 공존시킴으로써 새로운 태, 기능, 외관, 광택의 부여가 가능하며 이를 활용한 차별화된 고부가가치 시장의 창출이 기대된다. Acetate와 Tri-Acetate 모두 셀룰로오스의 친수기가 아세틸화된 구조를 가지는 소수성 섬유로 분자구조가 치밀하여 분산염료로 염색된다. 그러나 일반적으로 Acetate 섬유의 경우 Acetate용 일반분산염료를 사용하여 저온상압염색을 하는 반면, Tri-Acetate의 경우 고온고압 분산염료를 사용하여 고온고압염색을 한다. PET와 Tri-Acetate 복합소재의 경우, 두 소재의 염색거동이 비슷하여 고온고압 분산염료로 염색이 가능하지만 T/P 복합소재에 상응하는 염색을 위해서는 복합소재를 구성하는 각각의 섬유소재에 적합한 염료의 선정 및 염색법의 개발이 필요하다. 본 연구에서는 Tri-Acetate 및 T/P 복합소재에 대한 염색최적조건을 규명하고자 염색온도별, 2종의 분산염료의 농도별 염색성, 염색시료의 인열강도 및 견뢰도를 측정하여 적정조건을 도출하였다.

• Korean Journal of Food Science and Technology
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• 제17권2호
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• pp.107-112
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• 1985

Viscometric properties of japonica(Olchal) and japonica${\times}$indica(Hankang and Suwon 317) waxy rice starches were investigated. Light transmittance of starch suspension increased from $50^{\circ}{\sim}55^{\circ}C$ and remained constant after $75^{\circ}C$. Swelling power was in the order of Hankang, Suwon 317 and Olchal. Amylograph data revealed that Hankang had the highest viscosity at all reference points. The apparent viscosity of 5% starch suspension indicated that the j${\times}$indica starches were completely gelatinized after 30 min cooking at $65^{\circ}C$ whereas japonica starch at $70^{\circ}C$. The apparent viscosity of gelatinized starch at $121^{\circ}C$(15 psig) was higher compared to that of gelatinized one at $95^{\circ}C$. Hankang was the most susceptable to alkali gelatinization followed by Suwon 317 and Olchal.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제14권8호
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• pp.3887-3896
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• 2013

The aim of this study was to select yeast strain for quality optimization of distilled spirit which is prepared using rice. Five yeasts strains were compared for their brewing characteristics and showed normal fermentation pattern, but songcheon yeast(Y1) and distillery yeast(Y5) revealed higher fermentation ability than other samples tested. The analyzed results of fermented mashing showed that the distillery yeasts(Y4, Y5) had significantly much higher alcohol content, and songcheon yeast(Y1), distillery yeasts(Y4, Y5) had significantly higher ester content than other samples tested respectively, while the distillery yeasts(Y3, Y4, Y5) had significantly higher organic acid content than other samples tested. The analyzed results of distilled spirits which were distilled using copper distillery apparatus showed that the songcheon yeast(Y1) and distillery yeast(Y5) had a higher yield compared to other samples tested. In addition, the results of the aroma compounds such as ester and higher alcohol of distilled spirits among the five yeasts tested were similar to the analyzed results of fermented mashing. Siha aktivhefe 6 brennereihefe(Y5) indicated the highest overall preference including sensory evaluation and was selected as best yeast strain for quality optimization of distilled spirit which is prepared using rice.

• Journal of the Korean Society of Food Science and Nutrition
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• 제41권3호
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• pp.369-375
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• 2012

In this study, muffins were made with the addition of 50% acorn jelly powder and 0, 0.1, and 0.5% acorn ethanol extract powder. The moisture content of muffins decreased with an increase in the acorn ethanol extract powder concentration. Baking loss rate decreased with an increase in powder concentration. The lightness and yellowness of muffins decreased as the concentration of powder increased. Redness increased as the concentration of powder increased. The hardness of muffins increased, and cohesiveness decreased with an increase in powder concentration. Gumminess, and chewiness decreased by the addition of powder. The results of a sensory test showed that the texture quality of the muffin increased as the amount of added acorn increased. The taste of muffins increased with an increase in the powder concentration, but 1.0% acorn ethanol extract powder decreased. In terms of the overall acceptability, 0.1% acorn ethanol extract powder had the highest preference level.

• Food Engineering Progress
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• 제15권4호
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• pp.398-403
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• 2011

A dielectric barrier discharge plasma (DBDP) treatment system was fabricated and the optimum operating conditions for the plasma generation were determined in order to explore the potential of cold plasma as a non-thermal proessing technology. The microbial inactivation performance of the system was also evaluated against Staphyloocus aureus. The system consisted of power supply, transformer, electrode assembly and sample treatment plate. The input power was 220 V single phase AC and amplified to 10.0-50.0 kV on a transformer. A pulsed sine wave of frequency 10.0-50.0 kHz was introduced to the electrode embedded in ceramic as a dielectric barrier material in order to generate plasma at atmospheric pressure. Higher currents and consequently greater power were required for the plasma generation as the frequencies increased. A homogeneous and stable plasma was generated at currents of 1.0-2.0, and frequencies of 32.0-35.3 kHz. The optimum electrode-gaps for the plasma generation were 1.85 mm without loaded samples. More power was consumed as the electrode-gaps increased. The practically optimum electrode- gap was, however, 2.65 mm when samples were treated on slide-glasses for microbial inactivation. The maximum temperature increase after 10 min treatment was less than 20$^{\circ}C$, indicating no microbial inactivation effect by heat and thereby insuring a non-thermal method. The DBDP inactivation effect against Staphyloocus aureus increased linearly with treatment time up to 5 min, but plateaued afterward. More than 5 log reduction was achieved by 10 min treatment at 1.25 A.

• Korean Journal of Agricultural Science
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• 제8권1호
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• pp.97-107
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• 1981

This study was carried out in order to provide the basic data necessary to develop the effective and desirable cooking method on large scale for investigating the physical characteristics of cooked rices and studying optimum cooking conditions by pressure in kettle cooking rices. Milyang-15, local Japonica type and Milyang-23, high yielding Indica type major varieties cultivated in Korea were used as cooking sample after polishing 70% and 90% respectively, and the results obtained are summarized as follows. 1. The average moisture content of cooked rice by open kettle and pressure kettle method in typical households were 65.17% and 64.52%, respectively. 2. In water absorption capacity of rice grain Milyang-23 was 4.5% higher than Milyang-15, and maximum water content after absorption in Milyang-23 was 29.14%. 3. The expansion volume of cooked rice was changed proportionally by water absorption, heating temperature and time, and maximum expansion volume of cooked rice was 3.2 times greater than rice grain. 4. The gelatinization degree of cooked rice intensively concerning in hardness of rice grain was increased as water-to-rice ratio, heating temperature and time increased, and it was 0.44 in Milyang-23 and 0.64 in Milyang-15 under the optimum cooking conditions as 160% water-to-rice ratio, $0.2kg/cm^2$ cooking pressure and 25 minutes cooking time. 5. The hardness of cooked rice was decreased as water-to-rice ratio, heating temperature and time increased, and it showed 2.35kg/wt in 90% polished Milyang-23 and 2.0kg/wt in 90 polished Milyang-15 under optimum cooking conditions. For maintaining the same level of hardness of cooking rice Milyang-23 required 25% much more water than Milyang-15. 6. The elasticity of cooked rice was changed proportionally by water-to-rice ratio, heating temperature and time, and it appeared 19.2mm and 15.7mm in 90% polished Milyang-15 and Milyang-23 respectively. 7. The gumminess of cooked rice was decreased as water-to-rice ratio, heating temperature and time increased, and it showed 60 and 73 in 90% polished Milyang-23 and Milyang-15, respectively. 8. The optimum cooking time on differerent pressure in kettle took 25 minutes at $0.2kg/cm^2$, 20 minutes at $0.4kg/cm^2$, 15 minutes at $0.6kg/cm^2$, and 10 minutes at $0.8kg/cm^2$.

• Korean Journal of Soil Science and Fertilizer
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• 제42권5호
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• pp.399-407
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• 2009

Laser induced breakdown spectroscopy(LIBS) is an simple analysis method for directly quantifying many kinds of soil micro-elements on site using a small size of laser without pre-treatment at any property of materials(solid, liquid and gas). The purpose of this study were to find an optimum condition of the LIBS measurement including wavelengths for quantifying soil elements, to relate spectral properties to the concentration of soil elements using LIBS as a simultaneous un-breakdown quantitative analysis technology, which can be applied for the safety assessment of agricultural products and precision agriculture, and to compare the results with a standardized chemical analysis method. Soil samples classified as fine-silty, mixed, thermic Typic Hapludalf(Memphis series) from grassland and uplands in Tennessee, USA were collected, crushed, and prepared for further analysis or LIBS measurement. The samples were measured using LIBS ranged from 200 to 600 nm(0.03 nm interval) with a Nd:YAG laser at 532 nm, with a beam energy of 25 mJ per pulse, a pulse width of 5 ns, and a repetition rate of 10 Hz. The optimum wavelength(${\lambda}nm$) of LIBS for estimating soil and plant elements were 308.2 nm for Al, 428.3 nm for Ca, 247.8 nm for T-C, 438.3 nm for Fe, 766.5 nm for K, 85.2 nm for Mg, 330.2 nm for Na, 213.6 nm for P, 180.7 nm for S, 288.2 nm for Si, and 351.9 nm for Ti, respectively. Coefficients of determination($r^2$) of calibration curve using standard reference soil samples for each element from LIBS measurement were ranged from 0.863 to 0.977. In comparison with ICP-AES(Inductively coupled plasma atomic emission spectroscopy) measurement, measurement error in terms of relative standard error were calculated. Silicon dioxide(SiO2) concentration estimated from two methods showed good agreement with -3.5% of relative standard error. The relative standard errors for the other elements were high. It implies that the prediction accuracy is low which might be caused by matrix effect such as particle size and constituent of soils. It is necessary to enhance the measurement and prediction accuracy of LIBS by improving pretreatment process, standard reference soil samples, and measurement method for a reliable quantification method.