• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.4039-4045
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• 2014

The crystallization behavior of irradiated polypropylene (PP) and the blend is an important parameter for polymer processing. Blends of PP/low density polyethylene (LDPE) with different LDPE contents were prepared by melt mixing in a twin screw extruder. The effect of the LDPE content on the irradiation effectiveness of the PP/LDPE blend with trimethylolpropane-trimetacrylate (TMPTMA) as a crosslinking co-agent was investigated in conjunction with the LDPE loading in the blend. The non-isothermal crystallization and crystal structure were measured by DSC, X-ray diffraction (XRD), and polarized optical microscopy (POM). A decrease in the melting temperature of PP was observed due to irradiation, which may be due to the PP chain scissioning effect of irradiation. The Ozawa component n represents a rod shaped, disc shaped and sphere-shaped geometry of the crystal if the value corresponds to 2, 3 and 4, respectively. Based on Ozawa analysis, the values of n were 3.8 and 2.3 for the pure PP and PP blends with 30 wt% LDPE, respectively. The fact that the crystal geometry of PP changed from spherical to disc and rod shaped was confirmed by Ozawa analysis and POM. The ${\beta}$ form XRD peak of the PP/LDPE blend at $16.1^{\circ}$ disappeared after irradiation due to the crosslinking reaction.

• Polymer(Korea)
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• v.38 no.4
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• pp.471-476
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• 2014

Polycarbonate (PC) and acrylonitrile-butadiene-styrene (ABS) blends were prepared using a high shear extruder to investigate their thermal decomposition and mechanical properties with shear rate and shear time. In this experiment, high shear rate, from 1000 to 3000 rpm, in blending process was applied for 10 to 40 sec, respectively. At high shear rate over than 2000 rpm, the initial decomposition temperature was dropped significantly compared to a compounded sample because of thermal decomposition of the blend by high shear. Consequently, high shear processing gave an important effect on the mechanical and thermal properties of the PC/ABS blend. In particular, elongation of the blend decreased significantly with shear rate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.9
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• pp.1407-1414
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• 2014

Physicochemical properties of rice-based expanded snacks extruded with rice flour, high amylose starch, and isolated soy protein were investigated using a twin-screw extruder. The ingredients were extruded at various feed moisture contents (19~23%) and screw speeds (200~400 rpm) at a constant feed rate (43.4 kg/hr). Bulk density and apparent density of rice snacks were 0.06~0.21, and 0.55~0.65 respectively. Bulk density, apparent density, water absorption index, and breaking strength of rice snacks increased with increasing feed moisture content and decreasing screw speed. However, expansion and water solubility index of rice snacks increased with decreasing feed moisture content and increasing screw speed. Hunter's color L values of rice snacks was lower with increasing screw speed at feed moisture contents of 19% and 21%, but was not significantly different from a feed moisture content of 23%. On the other hand, a and b values of rice snacks were higher with increasing screw speed a feed moisture content of 19%. X-ray diffraction intensity of rice snacks decreased with decreasing feed moisture content and increasing screw speed. X-ray diffraction of rice snacks was V-type at feed moisture contents of 19% and 21% and screw speeds of 300, and 400 rpm. In the microstructure of the cross section of rice snacks, air cells in rice snacks were not well formed, and cell walls were thicker with increasing feed moisture content and decreasing screw speed.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.1036-1043
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• 1994

The silane crosslinking method was applied for the crosslinking of polyethylene (PE). Crosslinking of PE was performed by, first grafting vinyltrimethoxysilane(VTMOS) to the main chain of PE using an extruder at $200{\sim}210^{\circ}C$, followed by exposure to three different silane crosslinking conditions (1. immersed in $80^{\circ}C$ water, 2. at $80^{\circ}C$ air forced convection oven, 3. exposed to air at room temperature ). The thermal characteristic changes of PE resins with respect to the silane crosslinking conditions were studied by measuring the crystalline melting temperature, density and crosslinking reaction rate. Because silane crosslinking was carried out at solid state, crystalline melting temperature, crystallinity, crystal growth rate, crosslinking reaction rate and the change in the density of silane crosslinked PE were affected by crosslinking condition and the type of base resin. The properties of silane crosslinked PE were different from those of Peroxide crosslinked PE which was crosslinked at the molten state. It was found, from the result of DSC analysis, that silane crosslinked linear low density polyethylene(LLDPE) crosslinked at room temperature had no secondary melting peak because the crosslinking reaction proceeds slowly as the crystalline grows. After crystallization, the melting point of PE was lowered by crystalline interruption of crosslinked site.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.1-8
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• 1993

Extruded defatted soy flour (DSF) with twin screw extruder was compared with steam treated DSF for soy sauce fermentation. Independent variables of response surface methodology (RSM) for extrusion were barrel temperature $(145{\sim}165^{\circ}C)$, feed moisture content $(25{\sim}35%)$, and feed rate $(20{\sim}30\;kg/hr)$. Extrusion conditions for production of the extrudates having highest water absorption capacity, lowest bulk density and highest expansion ratio were obtained by regression analysis of each dependent variable. Electron photomicrographs revealed significant increase of porosity inside the koji made from extruded DSF. Therefore, growth of fungi inside the koji made from extrudates of DSF was accelerated to achieve higher activities of protease, ${\alpha}-amylase$, and glucoamylase compared to the koji made from steamed DSF. Although amino acid composition of soy sauces prepared from two different DSF did not show any significant difference, the content of free amino acids in soluble nitrogen compounds was higher $(13%{\pm}2)$ in soy sauce made from extruded SDF. During the whole period of fermentation color of soy sauce made from extrudates of DSF was darker. Sensory evaluation did not reveal any serious off-odor and off-taste in the soy sauce fermented from extruded DSF.

• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.361-368
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• 2006

Extruded ginseng was manufactured using twin-screw extruder under 300 rpm screw speed, 21 kg/hr feed rate, $80-150^{\circ}C$ extrusion temperature, and by addition of water (12.1-30.6%). Extraction yield and contents of total carbohydrate and uronic acid in extruded ginseng at room temperature extraction (RT) increased with increasing extrusion temperature, whereas those of boiling temperature extracts (BT) were not affected by increasing extrusion temperature. Contents of nonstarch polysaccharide (NSP) in RT and BT extracts increased 340 and 142%, respectively, compared to that of raw ginseng. Main sugar compositions of NSP in RT and BT extracts were arabinose, galactose, and glucose. Extraction yields of total and crude saponins in extruded ginseng at optimize extrusion condition were higher than that of raw ginseng. In RT extracts, molecular weights of polysaccharides from raw were higher than that of extruded ginseng polymer, whereas in BT extracts molecular weights of polysaccharides from extruded ginseng were higher than those of raw ginseng polysaccharides.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.627-634
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• 2020

Instead of lead, we intend to develop shielding materials for morphological implementation by mixing barium sulfate, an eco-friendly substance, and PLA filament, a 3D printer material. The environmental substance, barium sulfate powder and PLA filament, a 3D printer material, were used, and the shielding was made with a 3D printer after being fused into an extruder to mix the powder powder of barium sulfate with PLA. To check the mixing ratio of barium sulfate powder and PLA filament, the mixing input was analyzed, and the absorption dose by thickness according to barium sulfate content was obtained to check the shielding function of the mixed shielding. In the evaluation of the mixture of sulfate barium powder particles and PLA filaments, it was mixed in the most appropriate proportion when the content was 30% in the apparent and electron microscopic observation photographs. In the absorption dose results by thickness according to barium sulfate content, the difference between the content of 0% and the content of each % was greatest at 0.5 cm in thickness and the lowest dose value at 3 cm in thickness when the barium content was 30%. In addition, as the barium content began to increase at 30%, the absorbed dose value increased again. Instead of conventional lead, barium sulfate, an eco-friendly substance, could be mixed with PLA, a filament material, to create morphological shielding. Based on this study, it is expected that the mixing ratio of barium to the mixture is the most appropriate 30%, and will be used as the basis for the implementation of morphological shielding using 3D printers in the diagnosis and treatment section.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1765-1772
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• 2002

Three experiments were conducted to determine the feed processing method best suited for early and conventionallyweaned pigs, and to investigate the effects of different extrusion temperatures on ileal digestibility of amino acids in diets containing different protein sources. In exp.1, a total of 108 pigs (Landrace${\times}$Yorkshire${\times}$Duroc; 24 d of age and 7.60 kg average body weight) were alloted on the basis of sex, weight and ancestry to three treatments in a randomized complete block design. Feed processing methods used were mash (M), simple pellet (SP), and expanded pellet (EP). In exp. 2, a total of 96 pigs (Landrace${\times}$Yorkshire${\times}$Duroc; 14 d of age) were allotted on the basis of sex, weight, and ancestry to three treatments in a randomized complete block design. Diets were mash (M), expanded pellet (EP), and expanded pellet crumble (EPC). In exp. 3, a study was designed to investigate the effect of different extrusion temperatures (100, 120, and $140^{\circ}C$) over the control (untreated) on the ileal digestibility of amino acids in diets containing protein sources such as spray-dried plasma protein (SDPP), whey protein concentrate (WPC), and fish meal (FM). Results in exp.1 showed that ADG, ADFI and the F/G ratio of pigs fed the SP diet were improved (p<0.05) compared with those fed the M or the EP diets, but the digestibility of nutrients was not different (p>0.05) among the treatments. In exp. 2, pigs fed expanded pellet treatments (EP or EPC) had a significantly improved (p<0.05) F/G ratio compared to the pigs fed the M diet which was primarily attributed to the significant reduction (p<0.05) in ADFI, but the overall growth rate of pigs fed expanded pellet diets was not improved. In exp. 3, there was a significant interaction effect (p<0.05) between the extrusion temperature and protein source on the ileal digestibility of amino acids. With an extrusion temperature of $100^{\circ}C$, the ileal digestibility of Lys, Val, Gly and Ser was significantly lower in the diet containing WPC compared to the diet containing SDPP. Increasing the temperature to $120^{\circ}C$ led to significant differences (p<0.05) in the digestibility of Thr and Tyr between diets containing WPC and SDPP. Regardless of extrusion temperatures, the weaned pigs' diet containing either SDPP or FM had significantly higher Lys, Phe, Thr, Val, and Gly digestibility relative to the WPC diet. Results of the present study suggest that simple pelleting of diets containing protein sources such as whey protein concentrate, spray-dried plasma protein and fish meal would be better than the extruded or expanded pellet diets. Extruder or expander processing of weaned pigs' feed could reduce palatability and ileal digestibility of several amino acids and therefore may be responsible for a negative growth response in weaned pigs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.731-737
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• 2017

Substitution effect of fish meal and Saccharina japonica with soybean and rice bran in extruded pellet (EP) on juvenile abalone was determined. Two thousand five hundred and twenty juvenile abalone were distributed into 36 plastic containers. Four EP were prepared and extruder-pelletized. Twenty percent fish meal, 12% soybean meal and 14% Saccharina japonicawere included in the Control diet. Fifty percent of fish meal, combined 50% of fish meal and Saccharina japonica, and 100% of fish meal and Saccharina japonica were substituted with the same amount of soybean meal, and combined soybean meals and rice brans, referred to as FS50, FS50+SS50 and FS100+SS100 diets, respectively. Four domestic and 3 imported commercial diets for abalone and salted Saccharina japonica were prepared. The diets were fed to abalone once a day for 16 weeks. The highest survival was obtained in abalone fed FS50+SS50 diet. Weight gain and SGR of abalone fed FS50+SS50 diet was higher than those of abalone fed the FS50 and FS100+SS100 diets. Proximates of abalone was affected by dietary nutrient composition. In conclusion, 50% fish meal and combined 50% fish meal and Saccharina japonica could be replaced with the same amount of soybean meal and combined soybean meal and rice bran in EP of abalone.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.576-584
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• 2020

The extruder screw material is mainly SKD11, but the recent development of synthetic resins have increased the occurrence of chemical corrosion and wear. To solve this issue, high chromium cast iron is needed because of its good abrasion resistance and corrosion resistance, but its use is avoided because of its poor machinability. In this study, to improve the machinability of high chrome cast iron, 0, 0.5, 1.0, 1.5% of nickel, which has excellent workability, was added to high chromium cast iron with a composition of Fe-23Cr-2.5C-1.2Si-1.08Mn-0.48Mo-0.3V, and annealed after casting. Subsequently, the effect of nickel on the machinability and corrosion resistance was analyzed using a turning test and coin polarization test, and compared with SKD11. After casting using a high-frequency vacuum induction furnace, the annealing treatment was performed at 750 ℃ for five hours and then reheated at 1100 ℃ for five hours. A turning test after annealing at 750 ℃ showed that the machinability was improved remarkably when the nickel content was over 1.0%. In the potentiodynamic polarization test in a 5% NaCl solution, the corrosion resistance decreased with increasing nickel content in the as-cast and annealing treatment. On the other hand, after reheating, the corrosion resistance was best with a 1.5% nickel content.