• Journal of the Korean Wood Science and Technology
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• v.46 no.5
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• pp.565-576
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• 2018

Cellulose acetate (CA) has been widely utilized for composite materials due to its high transparency and thermal resistance. In this study, CNCs (cellulose nanocrystals) were reinforced in CA nanocomposites for fortifying mechanical properties of the composites. In addition, CA nanocomposites reinforced with CNCs were manufactured by extrusion/injection processes applied with CNC-predispersion method for achieving a high dispersion level of CNCs in the CA matrix. According to the analysis of mechanical properties, the CA nanocomposite with 3 wt% CNCs has the highest tensile and flexural strengths due to the reinforcing effect of CNC nanoparticles. Thermogravimetric analysis (TGA) showed that the addition of acid hydrolyzed CNCs slightly lowered the initial pyrolysis temperature of CA nanocomposite.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.3
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• pp.214-219
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• 2010

In this study, we fabricated tubular ceramic support for segmented-in-series solid oxide fuel cell (SOFC) by using CSZ(CaO-stabilized $ZrO_2$) as main material and activated carbon as pore former. Thermal expansion properties of ceramic support with different amounts of activated carbon were analyzed by using dilatometer to decide a suitable sintering temperature. The tubular ceramic supports with different amounts of activated carbon (5, 10, 15wt.%) were fabricated by the extrusion technique. After sintering at $1100^{\circ}C$ and $1400^{\circ}C$ for 5h., cross section and surface morphology of tubular ceramic support were analyzed by using SEM image. Also, the porosity, mechanical property, gas permeability of tubular ceramic supports was measured. Based on these results, we established the suitable fabrication technique of tubular ceramic support for segmented-in-series SOFC.

• Elastomers and Composites
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• v.54 no.4
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• pp.345-350
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• 2019

In this study, aliphatic polyketone (PK)/chopped carbon fiber (CCF) composites with various CCF contents were prepared using a modular intermeshing co-rotating twin screw extruder, and their mechanical and thermal properties such as tensile, flexural, and impact strength and thermal conductivity were investigated. The amount of CCF was increased from 0 to 50 wt%. The tensile and flexural strength of the PK/CCF composites increased as the CCF content increased, but the elongation at break and impact strength was lower than that of pure PK. Thermal properties such as heat distortion temperature and thermal conductivity increased as the CCF content increased. Morphological observations revealed that fiber orientation and interface adhesion between the PK and the CCF in the PK/CCF composites were formed due to the twin screw extrusion, which contributed to improving the mechanical and thermal properties of the composites.

• Korean Journal of Food Science and Technology
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• v.11 no.3
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• pp.192-199
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• 1979

With cells of Streptomyces spp K-45 isolated from soil, the immobilization of glucose isomerase by a series of treatments ; heat, carefully manipulated drying, extrusion with a thickening agent, and glutaraldehyde-induced crosslinking, was presented. This was aimed to obtain a mechanically stable form of whole cell containing glucose isomerase. The resulted pellet form had a good mechanical strength, compared with a commercial product, and showed 26 % of the activity recovery. The specific activity was 48.1 units per g of the dry material. The immobilized glucose isomerase generally showed properties similar to those of the soluble enzyme ; optimal pH at $7.5{\sim}9.0$, optimal temperature at $80{\sim}85^{\circ}C$, activation energy of 10.9 kcal/mole, and $K_m$ for glucose of 10.9M. The immobilized enzyme was very thermostable and pH stable.

• Korean Journal of Materials Research
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• v.9 no.3
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• pp.263-268
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• 1999

In this study, a new concept of aluminum-matrix composites and the possibility of in-situ processing are suggested, and preliminary results on AI- Ti system are presented. Fine powders of AI-lO% Ti were prepared by the gas atomization so that fine $Al_3Ti$ formed into flake shape. A 25v/o $Al_3Ti/Al$ composite sample was made by the pow­d er metallurgy process involving hot extrusion. Microstructure and mechanical behavior both at room temperature and high temperatures were analysed by OM, SEM, TEM and tension test. Microstructural characteristics and mechanical properties of the composites exhibited similar behavior to those of $SiC_w/2124$ composites. Merits and drawbacks of the $Al_3Ti/Al$ composites are discussed together with a possibility of further improvement.

• Korean Journal of Food Science and Technology
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• v.16 no.3
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• pp.267-272
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• 1984

${\beta}-Fructofuranosidase$ was immobilized covalently on the oxidized microbial wall of a Penicillium spp. 'PS-8', which is totally different from the conventional whole cell immobilization in concept. The immobilization of ${\beta}-fructofuranosidase$ by a series of treatments; oxidation of microbial cells with sodium metaperiodate, enzyme loading on the oxidized cells, extrusion, and crosslinking induced by glutaradehyde, were carried out. The final product had a good mechanical strength and showed 26% of the applied enzyme activity. The specific activity was 750 units per g of the dry cell product. The immobilized enzyme showed the kinetic parameters as follows; optimum pH at 5, optimum temperature at $55^{\circ}C$, activation energy of 19 kJ $mol^{-1}$, and apparent Km of 55 mM.

• Smart Media Journal
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• v.8 no.3
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• pp.95-103
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• 2019

The global manufacturing industry has reached the limit to growth due to a long-term recession, the rise of labor cost and raw material. As a solution to these difficulties, we promote the 4th Industry Revolution based on ICT and sensor technology. Following this trend, this paper proposes the design of a model using manufacturing data in the protection film process for smart manufacturing innovation. In the protective film process, the manufacturing data of temperature, pressure, humidity, and motion and thermal image are acquired by various sensors for the raw material blending, stirring, extrusion, and inspection processes. While the acquired manufacturing data is stored in mass storage, A.I. platform provides time-series image analysis and its visualization.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.5
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• pp.1352-1363
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• 2015

This study was carried out to investigate the characteristics of the dependent variables depending on the condition changes of independent variable of the operation and the material during the production of collets added with rice and dried shrimp by using single extruder to utilize as basic data for the manufacture of extrusion collets. A total of 7 independent variables were set up as a raw, 20, 40 and 60 mesh for the powder particle size of rice; 12, 14, 16 and 18% for the moisture content of rice; 2, 4, 6 and 8% for the addition amount of dried shrimp; 90, 95, 100 and $110^{\circ}C$ for the barrel temperature; 210, 280 and 340 rpm for the screw speed; 4, 6, 8 and 10 mm for the discharge port diameter; 30, 40, 50 and 60 kg/h for the input amount of the mixed material. The characteristics of the dependent variables including puffing ratio, moisture content, lightness, uniformity, productivity of collets was to be studied by changing the conditions of the independent variables. As a results of this study, 20 mesh of powder particle size of rice, 14% of moisture content of rice, 4% of addition amount of dried shrimp, $100^{\circ}C$ of barrel temperature, 280 rpm of screw speed, 6 mm of discharge port diameter and 50 kg/h of input amount of mixed material were found to be the most preferable over other independent variables for the production of extrusion collets. In conclusion, it is necessary to set the independent variable in order to produce the high quality collets added with the rice as the main raw material and dried shrimp as the sub-materials.

• Composites Research
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• v.34 no.4
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• pp.241-248
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• 2021

As the electric vehicle market grows, there is an issue of light weight vehicles to increase battery efficiency. Therefore, it is going to replace the battery module cover that protects the battery module of electric vehicles with high strength/high heat-resistant polymer composite material which has lighter weight from existing aluminum materials. It also aims to respond to the early electric vehicle market where technology changes quickly by combining 3D printing technology that is advantageous for small production of multiple varieties without restrictions on complex shapes. Based on the composite material mechanics, the critical length of glass fibers in short glass fiber (GF)/polycarbonate (PC) composite materials manufactured through extruder was derived as 453.87 ㎛, and the side feeding method was adopted to improve the residual fiber length from 365.87 ㎛ and to increase a dispersibility. Thus, the optimal properties of tensile strength 135 MPa and Young's modulus 7.8 MPa were implemented as GF/PC composite materials containing 30 wt% of GF. In addition, the filament extrusion conditions (temperature, extrusion speed) were optimized to meet the commercial filament specification of 1.75 mm thickness and 0.05 mm standard deviation. Through manufactured filaments, 3D printing process conditions (temperature, printing speed) were optimized by multi-optimization that minimize porosity, maximize tensile strength, and printing speed to increase the productivity. Through this procedure, tensile strength and elastic modulus were improved 11%, 56% respectively. Also, by post-processing, tensile strength and Young's modulus were improved 5%, 18% respectively. Lastly, using the FEA (finite element analysis) technique, the structure of the battery module cover was optimized to meet the mechanical shock test criteria of the electric vehicle battery module cover (ISO-12405), and it is satisfied the battery cover mechanical shock test while achieving 37% lighter weight compared to aluminum battery module cover. Based on this research, it is expected that 3D printing technology of polymer composite materials can be used in various fields in the future.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.13-26
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• 1994

The present study was focused on investigation of proper processing conditions to develop physicochemical properties of extrudates using sea mustard and corn by single extruder. Response surface analysis was used to evaluate effects of extrusion variables on the quality of the extrudates. Physicochemical dependence variables of sea mustard extrudates with corn grits show a significance correlation of within $5\%$. Among the various dependence variables, the expansion ratio showed a high correlation with bulk density, break strength, water solubility index and yellowness. Bulk density correlated closely with water solubility index; break strength with water absorption index and lightness, and water absorption index with lightness. Water solubility index and lightness showed a significance correlation with yellowness of within $0.5\%$. Three dimensional graphic analysis on response surface regression was conducted with each of the dependent variables which revealed statistically significant relationship to independent variables: $15{\sim}21\%$ moisture content, $10{\sim}30\%$ sea mustard content and $95{\sim}115^{\circ}C$ die temperature. Expansion ratio decreased with increasing moisture and sea mustard content. It showed the highest value at $18\%$ moisture content, $10\%$ sea mustard content and $95^{\circ}C$ die temperature. and the lowest value was at $21\%$ moisture content, $30\%$ sea mustard content and $105^{\circ}C$ die temperature. Bulk density was highest at $21\%$ moisture content, $30\%$ sea mustard content and $105^{\circ}C$ die temperature. On the other hand, it was lowest at $18\%$ moisture content, $10\%$ sea mustard content and $95^{\circ}C$ die temperature. Break strength was highest at $18\%$ moisture content, $10\%$ sea mustard content and $115^{\circ}C$ die temperature, but lowest at $21\%$ moisture content, $30\%$ sea mustard content and $105^{\circ}C$ die temperature. Water solubility index increased in the range of $43.9{\sim}54.8\%$ as the moisture content increased.