• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 한국태양에너지학회, 한국에너지공학회 1993년도 춘계 공동학술발표회 초록집
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• pp.126-131
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• 1993

Differential Scanning Calorimetry (DSC) and solvent swelling technique have been applied for identifying physical transition temperatures in the macromolecular structure of coals. The transition processes seem to be associated with physical relaxation of the coal structure and are irreversible processes. In Pittsburgh No. 8 high volatile bituminous (hvb) coat one physical transition was noted at 250-30$0^{\circ}C$ (at 8$^{\circ}C$/min) without any significant accompanying weight loss. Coals of higher rank than high volatile bituminous, i.e., Upper Freeport medium volatile bituminous (mvb) and Pocahontas No.3 low volatile bituminous (lvb) coals, exhibit structural relaxation just before the major thermal decomposition process and a sharp increase in solvent swellability accompanies this relaxation. In the case of both the Pittsburgh No.8 and the Upper Freeport coat structural relaxations at around 36$0^{\circ}C$ seem to coincide with release of "guest molecules".les".uot;.

• Korean Journal of Food Science and Technology
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• 제28권3호
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• pp.580-586
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• 1996

Gelatinization behavior and morphology of epichlorohydrin-crosslinked potato starches (XPs) were investigated. Native potato starch showed a very steep single stage swlling pattern, but crosslinked starches showed various patterns with the degree of crosslinking. Swelling power, solubility and light transmittance were reduced drastically as the degree of crosslinking increased. Brabender initial pasting temperature and peak temperature of crosslinked starches increased because the crosslinking reinforces the intermolecular net work of the starches. Although the swelling of the potato starch granule was inhibited by crosslinking as compared to that of the native one, Brabender peak viscosities (6.5% w/v, db) were on the order of 2,500 units for the native potato starch, 3,700 for the XP with 2.300 anhydroglucose units per crosslinking (AGU/CL) and 3,400 for the XP with 2,100 AGU/CL, due to the decreased breakdown of the swollen granule resulting from the resistance to heat and shear. The XP with 1,900 AGU/CL, however, did not show the peak viscosity and the viscosity was on the order of 500 units because of the excessive unhibition of the swelling. Unlike the native potato starch, 6.5%(m/v, db) pastes of the crosslinked potato starches could form gels, which could be predicted from the Brabender setback and consistency index. When the degree of crosslinking is low, random contraction and radial swelling of the granule was possible. As the degree of crosslinking increased, morphological change became similar to the single dimensional tangential swelling observed from the lenticular wheat starch. These morphological change during heating in excess water explained the gelatinization behaviors of crosslinked starches tested.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• 제2권3호
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• pp.165-174
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• 2004

In order to simultaneously vitrify the ion exchange resin(IER) and combustible dry active waste(DAW) generated from Korean nuclear power plants, a vitrification pilot test was conducted using an induction cold crucible melter(CCM) . The energy necessary for startup of the glass using a Ti-ring was evaluated as about 290 kWh. The power supplied from a high frequency generator to melt the glass properly was ranged from 160 to 190 kW without any interruption. When the mixture of the IER and DAW was fed into the CCM, the concentration of CO was lowered up to 1/40 compared to feeding the IER solely. It may be caused by the DAW which can produce about 1.8 times higher heat compared to the IER. When the swelling phenomenon occurred in the glass melt, the concentration of $NO_2$, oxidizing gas, was higher than NO, reducing gas. Total feed amounts of the IER and DAW were 368 and 751 kg, respectively. And then, about 74 of volume reduction factor was achieved.

• Nuclear Engineering and Technology
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• 제46권2호
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• pp.169-182
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• 2014

High-performance research reactors require fuel that operates at high specific power to high fission density, but at relatively low temperatures. Research reactor fuels are designed for efficient heat rejection, and are composed of assemblies of thin-plates clad in aluminum alloy. The development of low-enriched fuels to replace high-enriched fuels for these reactors requires a substantially increased uranium density in the fuel to offset the decrease in enrichment. Very few fuel phases have been identified that have the required combination of very-high uranium density and stable fuel behavior at high burnup. U-Mo alloys represent the best known tradeoff in these properties. Testing of aluminum matrix U-Mo aluminum matrix dispersion fuel revealed a pattern of breakaway swelling behavior at intermediate burnup, related to the formation of a molybdenum stabilized high aluminum intermetallic phase that forms during irradiation. In the case of monolithic fuel, this issue was addressed by eliminating, as much as possible, the interfacial area between U-Mo and aluminum. Based on scoping irradiation test data, a fuel plate system composed of solid U-10Mo fuel meat, a zirconium diffusion barrier, and Al6061 cladding was selected for development. Developmental testing of this fuel system indicates that it meets core criteria for fuel qualification, including stable and predictable swelling behavior, mechanical integrity to high burnup, and geometric stability. In addition, the fuel exhibits robust behavior during power-cooling mismatch events under irradiation at high power.

• Journal of the Korean Society of Food Science and Nutrition
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• 제39권4호
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• pp.573-579
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• 2010

This study investigated starch properties of 'Daehak waxy corn (DWC)' with different harvest times. The DWCs were harvested at 4 days before suitable time (BST), suitable time (ST) and 4 days after suitable time (AST). As harvest time was delayed, starch yield and amylopectin content of DWC starch increased from 43.21 to 52.73%, and from 90.79 to 92.83% based on dry weight, respectively. As harvest time was postponed, enzymatic digestibility and water solubility of DWC starch decreased from 81.43 to 80.58%, and from 10.23 to 9.23%. However, water binding capacity and swelling power of DWC starch increased from 227.94 to 244.88%, and from 24.75 to 29.74%, respectively. Retrogradation viscosity of starch was the lowest in DWC harvested at AST. There was a high correlation coefficient among starch properties of DWC, such as starch yield, enzymatic digestibility, water binding capacity, swelling power, water solubility and retrogradation viscosity (p<0.01). As harvest time was deferred, enzymatic digestibility, water solubility and retrogradation viscosity decreased; however, amylopectin content increased, and water binding capacity and swelling power significantly increased with increasing amylopectin content.

• Journal of the Korean Society of Food Science and Nutrition
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• 제39권4호
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• pp.542-547
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• 2010

Physico-chemical properties of starches from potato cultivars with different colors were investigated. White Atlantic potato had 10% higher starch yield than violet Bora Valley potato. It turned out that the shape and structure of Atlantic and Bora Valley potato starch were the same by mechanical analysis using X-ray and SEM. The ratio of $50\;{\mu}m$ particle in starches from Atlantic and Bora Valley potato was $45.44\pm2.79%$ and $42.37\pm1.03%$ respectively. The particle size of Atlantic potato starch was less than that of Bora Valley; however, there was no significant difference (p<0.05). As for moisture coupling, there was no difference (p<0.05) between the two potatoes. Swelling power showed a high increase from $65^{\circ}C$ to $80^{\circ}C$. The swelling power of Atlantic starch was higher by about 0.3% than that of Bora Valley at $90^{\circ}C$. Since Atlantic has smaller starch particles than Bora Valley, more starch particles are contained in the same size, and hence a difference in swelling power. As a result of measuring the gelatinization of potato starches from Atlantic and Bora Valley, a higher gelatinization start, climax, and complete temperatures occurred at Bora Valley than Atlantic. As for gelatinization enthalpy, Bora Valley starch with a higher gelatinization temperature consumed more energy for gelatinization.

• Korean Journal of Food Science and Technology
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• 제36권6호
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• pp.879-884
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• 2004

Effects of soaking time and particle size on physicochemical properties of nonwaxy rice flour were investigated. Nonwaxy rice grains were soaked at $4^{\circ}C$ for 0, 1, 12, and 24 hr, dried at room temperature, and milled. Resulting flours were passed through 45-mesh ($<355\;{\mu}m$, IL45) and 100-mesh ($<150\;{\mu}m$, IL100) sieves and separated into $<40\;{\mu}m\;and\;40-100\;{\mu}m$ series. IL45 series showed higher amount of large particles ($40-100\;{\mu}m$) than IL100 series. As the soaking time increased, protein and ash contents decreased, and amylose content, water-binding capacity, swelling power, and solubity of nonwaxy rice flours increased. Swelling power and solubility of nonwaxy rice flours also increased between $65-85^{\circ}C$. Water-binding capacity, swelling power, and solubility of IL100 series were higher than those of IL45 series. 12 hr-soaked nonwaxy rice flour pastes showed higher peak viscosity and breakdown but lower setback and viscosity at 95 and $50^{\circ}C$ than 1 hr-soaked ones. X-Ray diffractograms of nonwaxy rice flours were not affected, whereas surface appearance was affected, by soaking time and particle size.

• Korean Journal of Food Science and Technology
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• 제37권1호
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• pp.44-49
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• 2005

Physicochemical properties of hydroxypropylated rice starches were investigated. Swelling power of hydroxypropylated rice starch increased at relatively lower temperature than native rice starch. Solubility of hydroxypropylated rice starch was lower (1.9-13.4%) than that of native rice starch (2.2-13.8%), and increased with increasing amount of propylene oxide. Pasting temperature ($66.2-70.8^{\circ}C$) and peak viscosity (2,843-3,395cp) of hydroxypropylated rice starch were lower than those of native starch ($71.6^{\circ}C,\;3,976\;cp$) and decreased with increasing amount of propylene oxide, regardless of reaction time. DSC thermal transitions of hydroxypropylated rice starches shifted toward lower temperature. Amylopectin-melting enthalpy of hydroxypropylated rice starch decreased (11.8-9.8J/g) with increasing amount of propylene oxide and was lower than that of native starch (11.9 J/g). These results indicate hydroxypropylation lowered swelling power and gelatinization temperatures of rice starch, because internal bonds of rice starch molecules were sterically weaken by substituted hydroxypropyl groups.

• Korean Journal of Food Science and Technology
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• 제35권4호
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• pp.551-555
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• 2003

The physicochemical properties of starches from Korean and Chinese red bean were investigated. Korean red bean starch (KRBS) contained lower water content, but higher crude fat and carbohydrate content than those of Chinese red bean starch (CRBS). The round shape of starch granules from Korean and Chinese red bean was observed. The granule size of KRBS was smaller than that of CRBS. The whiteness of KRBS (87.22%) was significantly higher than that (86.16%) of CBRS. X-ray diffraction patterns between KRBS and CRBS were not significantly different, resulting in showing C type. There was significant difference in amylose content between KRBS and CRBS. The blue value of KRBS was 1.02, which was higher than that of CRBS. Swelling power of KRBS was higher up to $75^{\circ}C$ than that of CRBS, but then decreased. Solubility showed the same pattern as the swelling power. Our findings suggest that Korean red bean has better quality than Chinese red bean in terms of the physicochemical properties.

• The Korean Journal of Food And Nutrition
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• 제30권5호
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• pp.1119-1126
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• 2017

Quality characteristics of commercially available soybean and mung-bean flours in Korea were evaluated relative to product information such as bean content, price, chromaticity, proximate composition, water binding capacity, swelling power and solubility. Origin of raw materials was 23 in domestic products and 19 in imported products. The price of the product was 3.48 times more for raw soybean flour, 3.34 times more for fried soybean flour, and 3.47 times more for mung bean flour compared to imported soybean. In the domestic products, the lightness of raw soybean flour was higher than roasted soybean flour. The redness and yellowness of roasted soybean flour were higher than raw soybean flour. Moisture content of raw soybean flour was higher than roasted soybean flour, and crude fat, crude protein and carbohydrate content were higher in imported soybean flour. Ash and crude protein contents of mung bean were slightly higher than imported products. Water binding capacity of roasted soybean flour in domestic products was higher than raw soy flour, and there was no significant difference in solubility and swelling power. Correlation between quality characteristics of commercially available soybean and mung-bean flours products was found to be highly significant among measured items, except for solubility.