• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.689-692
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• 2008

HSC(High Strength Concrete) have superior properties well as improvement in durability compared with normal strength concrete. In spite of durability of HSC, explosive spalling of concrete is serious problem in structure safety. Therefore, Solving methods are required to control the explosive spalling. The properties of concrete are affected by changes of temperatures. Compressive strength and elasticity modulus were degraded depending on a rise of temperatures. Also, change in microstructure and dehydration of concrete subjected to high temperatures. This paper is concerned with change in microstructure and dehydration of the alumino silicate fire protection materials at high temperatures. The testing methods of fire protection materials in high temperature properties are make use of SEM, TG-DSC and XRD. From the experimental test results, influence of high temperatures on microstructure of alumino-silicate fire protection material was identified, including chemical dehydration of C-S-H and CH. The chemical dehydration of CH under various temperatures from to 450 to 600$^{\circ}$C has been measured using the TG-DSC. However, developed alumino silicate fire protection materials showed good stability in high Temperatures. Thus, the results indicate that it is possible to fireproof panels, fire protection of materials.

• International Journal of Fluid Machinery and Systems
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• v.5 no.3
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• pp.134-142
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• 2012

The competition to deliver ultra-low emitting vehicles at a reasonable cost is driving the automotive industry to invest significant manpower and test laboratory resources in the design optimization of increasingly complex exhaust after-treatment systems. Optimization can no longer be based on traditional approaches, which are intensive in hardware use and laboratory testing. The CFD is in high demand for the analysis and design in order to reduce developing cost and time consuming in experiments. This paper describes the development of a comprehensive practical model based on experiments for simulating the performance of automotive three-way catalytic converters, which are employed to reduce engine exhaust emissions. An experiment is conducted to measure species concentrations before and after catalytic converter for different loads on engine. The model simulates the emission system behavior by using an exhaust system heat conservation and catalyst chemical kinetic sub-model. CFD simulation is used to study the performance of automotive catalytic converter. The substrate is modeled as a porous media in FLUENT and the standard k-e model is used for turbulence. The flow pattern is changed from axial to radial by changing the substrate model inside the catalytic converter and the flow distribution and the conversion efficiency of CO, HC and NOx are achieved first, and the predictions are in good agreement with the experimental measurements. It is found that the conversion from axial to radial flow makes the catalytic converter more efficient. These studies help to understand better the performance of the catalytic converter in order to optimize the converter design.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2349-2356
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• 2014

The recycling technology by the catalytic conversion is one of the most promising techniques for the $CO_2$ treatment of coal burning power plant flue gases. The conversion of $CO_2$ to valuable product of $CH_4$ can be used as a fuel to run the turbine for electricity generation. Through this technique, the amount of coal needed for the combustion in a gas turbine can be reduced as well as $CO_2$ emissions. Therefore, a series of catalysts based on cerium oxide doped with copper, nickel and manganese were prepared by impregnation method. From the characterization analysis, it showed that the prepared catalysts calcined at $400^{\circ}C$ were amorphous in structure with small particle size in the range below 100 nm. Meanwhile, the catalyst particles were aggregated and agglomerated with higher surface area of $286.70m^2g^{-1}$. By increasing the calcination temperature of catalysts to $1000^{\circ}C$, the particle sizes were getting bigger (> 100 nm) and having moderate crystallinity with lower surface area ($67.90m^2g^{-1}$). From the catalytic testing among all the prepared catalysts, Mn/Ce-75/$Al_2O_3$ calcined at $400^{\circ}C$ was assigned as the most potential catalyst which gave 49.05% and 56.79% $CO_2$ conversion at reaction temperature of $100^{\circ}C$ and $200^{\circ}C$, respectively.

• Journal of Energy Engineering
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• v.7 no.1
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• pp.103-112
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• 1998

A high temperature fabric filter was developed and characterized in order to solve the various problems encountered in the operation of industrial fabric filters. Four kinds of dusts generated in the typical domestic industry were used for its characterization, coke dust from a steel manufacturing process, cement dust from a cement manufacturing process, fly ash from a fluidized-bed combustor, and incinerator ash from a waste plastics incinerator. The physical and chemical properties of the high temperature fabric filter were analyzed in terms of mean flow pore pressure, bubble point pore diameter, mean flow pore diameter, pore size distribution, and the changes in tensile strength and initial elastic modulus under $SO_2$ and $NO_2$ atmospheres. Pressure drop, dust penetration, and figure of merit for the fabric filter were also investigated in a bench-scale filter testing unit. The fabric filter developed in this study had good physical and chemical filter properties and showed a very applicability to typical industrial dusts treatments.

• Korean journal of food and cookery science
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• v.32 no.1
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• pp.1-8
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• 2016

This study aimed to enhance the applications of dates as a food material that can be utilized and stored easily by improving the inefficient process of the traditional cooking procedure. To this end, this study investigated the physico-chemical and nutritional properties of jujube pulp powder, and compared the traditional and newly developed methods of making yakbap, yakpyon, and jujube porridge. According to the analysis of physical and chemical properties, the jujube pulp powder contained 5.4% moisture, 2.6% crude ash, 6.6% crude protein, 0.35% crude fat, and 4.7% crude fiber. The water activity was 0.95% in jujube pulp while it was 0.24% in jujube pulp powder. In addition, the jujube pulp powder had a total sugar content of 70.4% and reducing sugar content of 6.3%. The vitamin C was content was estimated to be 68.5 mg/100 g in the jujube pulp powder and the jujube pulp contained 6.2 g/100 g of dietary fiber. Major minerals were K, Mg, and Ca. After appointing jujube pulp powder (new method) to a test group and jujube pulp (traditional method) to a control group, the sensory evaluation and acceptance testing were conducted for yakbap, yakpyon, and jujube porridge. As a result, there was no significant difference in any sensory factors tested (p<0.05). It was found that making and storing jujube pulp powder by drying jujube pulp is a useful way of utilizing jujube because Yakbab, Yakpyun and jujube porridge were found to have a relatively good appearance, color, flavor, taste, texture and overall acceptance.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.3
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• pp.375-381
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• 2012

Two experiments were conducted to establish a digestible energy (DE) content prediction model of rapeseed meal for growing-finishing pig based on rapeseed meal's chemical composition. In experiment 1, observed linear relationships between the determined DE content of 22 rapeseed meal calibration samples and proximate nutrients, gross energy (GE) and neutral detergent fiber (NDF) were used to develop the DE prediction model. In experiment 2, 4 samples of rapeseed meal selected at random from the primary rapeseed growing regions of China were used for testing the accuracy of DE prediction models. The results indicated that the DE was negatively correlated with NDF (r = -0.86) and acid detergent fiber (ADF) (r = -0.73) contents, and moderately correlated with gross energy (GE; r = 0.56) content in rapeseed meal calibration samples. In contrast, no significant correlations were found for crude protein, ether extract, crude fiber and ash contents. According to the regression analysis, NDF or both NDF and GE were found to be useful for the DE prediction models. Two prediction models: DE = 16.775-0.147${\times}$NDF ($R^2$ = 0.73) and DE = 11.848-0.131${\times}$NDF+0.231${\times}$GE ($R^2$ = 0.76) were obtained. The maximum absolute difference between the in vivo DE determinations and the predicted DE values was 0.62 MJ/kg and the relative difference was 5.21%. Therefore, it was concluded that, for growing-finishing pigs, these two prediction models could be used to predict the DE content of rapeseed meal with acceptable accuracy.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.7
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• pp.669-674
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• 2013

A three-dimensional hydrogel scaffold has been proposed for the effective production of biomimetic intestinal villi to reduce ethical and cost problems caused by animal testing in pharmaceutical development. This study explores an experimental approach to develop a new technique based on laser machining and microdrilling processes to produce a plastic mold for the fabrication of a three-dimensional hydrogel scaffold. For process optimization, both the laser machining and the microdrilling experiments are conducted by varying the experimental conditions, and structural characterization of the mold and intestinal villi were performed using SEM (scanning electron microscope) and OM (optical microscope) images. Polycarbonate (PC) was used as a candidate material. The experimental results show that intestinal villi can be fabricated by both laser and microdrilling machining processes.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.223-230
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• 2001

The Monkman-Grant (M-G) and its modified parameters were estimated for modified type 316LN and $9{\sim}12Cr-1Mo$ steels with chemical variations. Several sets of creep data were obtained by constant-load creep tests in $550-650^{\circ}C$ ranges. The relation parameters, m, $m^*$, C and $C^*$ were proposed and discussed for two alloy systems. In creep fracture mode, type 316LN steel showed domination of the intergranular fracture caused by growth and coalescence of cavities. On the other hand, the Cr-Mo steel showed transgranular fracture of the ductile type caused from softening at high temperature. In spite of the basic differences in creep fracture modes as well as creep properties, the M-G and its modified relations demonstrated linearity within the $2{\sigma}$ standard deviation. The value of the m parameter of the M-G relation was 0.90 in the 316LN steel and 0.84 in the Cr-Mo steel. The value of the $m^*$ parameter of the modified relation was 0.94 in the 316LN steel and 0.89 in Cr-Mo steel. The modified relation was superior to the M-G relation because the $m^*$ slopes almost overlapped regardless of creep testing conditions and chemical variations to the two alloy systems.

• Membrane Journal
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• v.18 no.1
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• pp.35-43
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• 2008

In this study, we tried to solve membrane fouling with membranes made by fine nano-particle in MBR process. And we confirmed good fouling resistance in pilot test. In this test, we confirmed our membrane with titania out-standing quality by testing in the pilot long-term test by comparing to other company product. Our membrane keep up steadily $20{\sim}25 L/m^2{\cdot}hr$ high flux in $7,000{\sim}13,000mg/L$ MLSS high sludge concentration. In addition to this quality, we studied membrane flux character related membrane arrangement, membrane-air line arrangement, air-line hole size, cleaning solution concentration, treatment method, etc. Using the optimization of this additional parameter, we tried to search method of maximizing membrane quality.

• Environmental Engineering Research
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• v.20 no.2
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• pp.127-132
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• 2015

Perfluorooctane sulfonate (PFOS) and Perfluorooctanoic acid (PFOA) are persistent environmental pollutants, extremely stable, and possibly adversely affect human health. They are widely used in many industries and consumer goods, including sunscreen products. These substances are stable chemicals made of long carbon chains, having both lipid- and water-repellent qualities. The research objectives are (1) to find the most effective method for the preparation of semi-liquid samples by comparing solid phase extraction (SPE) and centrifugation after Pressurized liquid extraction (PLE), and (2) to determine the contamination levels of PFOS and PFOA in waterproof sunscreen samples. All sunscreen samples were analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Sunscreen samples were purchased from domestic and international brands sold in Thailand. Special chemical properties were considered for the selection of samples, e.g., those found in waterproof, sweat resistant, water resistant, and non-stick products. Considering the factors of physical properties, e.g., operation time, chemical consumption, and recovery percentage for selecting methods to develop, the centrifugation method using 2 mL of extracted sample with the conditions of 12,000 rpm and $5^{\circ}C$ for 1 hour after PLE was chosen. The highest concentrations of PFOS and PFOA were detected at 0.0671 ng/g and 21.0644 ng/g, respectively. Even though present concentrations are found at ng/g levels, the daily use of sunscreen products is normally several grams. Therefore, a risk assessment of PFOS and PFOA contamination in sunscreen products is an important concern, and more attention needs to be paid to the long-term effects on human health.