• Food Science and Biotechnology
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• v.14 no.5
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• pp.676-680
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• 2005

This study investigated the effect of thawing rate on the physicochemical properties of frozen ostrich meat. Five different thawing rates (0.33, 0.54, 0.61, 0.68, and 0.78 cm/h) were delivered by controlling the air velocity as heat convection at $15^{\circ}C$. The pH value decreased with increasing thawing rate (p<0.05). In color measurement, $L^*$-values of all treatments were lower and $b^*$-values higher than those of control, but $a^*$-values were not significantly different among the treatments except at the thawing rate of 0.33 cm/h. Increasing thawing rate tended to improve the water holding capacity (WHC) of the samples. Thawing loss decreased with increasing thawing rate and significantly higher cooking loss was observed at the thawing rate of 0.33 cm/h. Thiobarbituric acid reactive substance (TBARS) levels of all treatments were significantly higher than that of control (p<0.05). Increasing thawing rate tended to decrease the total volatile basic nitrogen (TVBN) value. These results indicated that a rapid thawing process at $15^{\circ}C$ improved the quality of frozen ostrich meat.

• Korean Journal of Materials Research
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• v.13 no.9
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• pp.613-618
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• 2003

The magnetic heating effect of $SiO_2$coated $ \Upsilon-Fe_2$$O_3$nanocomposite particle due to magnetic relaxational loss of superparamagnetic regime was investigated by measuring the generated heat from nanocomposite particles in alternative applied magnetic fields. The commercial $ \Upsilon-Fe_2$$O_3$nanoparticles were coated by SiO$_2$in water solution with TEOS and the synthesized nanocomposite powders and its magnetic properties were characterized and compared with the raw$ \Upsilon-Fe_2$$O_3$nanoparticles. The 10∼30 nm sized $ \Upsilon-Fe_2$$O_3$. nanoparticles were coated by 5 nm thickness of amorphous $SiO_2$film. The nanocomposite particle has very low Mr and Hc value showing superparamagnetic behavior The magnetic heating effect of nanocomposite particle on surface coating phase of $SiO_2$was discussed in terms of superparamagnetic behaviors of each particles, and their potential for hyperthermia application was evaluated.

• Journal of Fashion Business
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• v.13 no.2
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• pp.78-86
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• 2009

When scouring and contraction finishing at $90^{\circ}C$ using Relaxer or Rotary Washer contraction and weight loss ratio in warp and weft directions were excellent. Also surface state of fabric after drying or sanding treatment was excellent without crease. Low melting polyester fabric showed a complete melting bond by heat setting(P/S) at above $160^{\circ}C$. The alkali hydrolysis reaction of polyester showed the breakpoint in the weight loss behavior test, polyester yarn showed a breakpoint ranging from 25% to 28%. This is due to the difference of the hydrolysis rate between regular polyester and soluble polyester. Initially the soluble polyester was eluted and micro-fibrillized 5 times faster than a regular polyester. At a later time, a regular polyester was reduced weight to impart a proper flexibility and drape property to the fabric. As a result of surface sanding finishing, the surface of interior fabric showed a surface state most stabilized when using Mesh No. 220 in mono 0.2d after elution finishing. When the rotation direction of sanding roller was pro-, pro-, pro-, and retro-direction, a directional effect of tuft was not shown, a writing effect as suede was exhibited and a surface state was even. Sublimation fastness was 3-4 class for polyester and 2-4 class for nylon. Light fastness 3-4 class after lapse of 100 hours and 2-4 class after lapse of 160 hours. Abrasion fastness was 3-4 class on wet and 4-5 class on dry Laundry fastness was 2-4 class. As such, the abrasion fastness is slightly reduced upon wetting and the use thereof for interior is excellent, whereas laundry fastness is slightly lowered.

• Advances in materials Research
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• v.13 no.3
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• pp.161-171
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• 2024

This study aimed to investigate the effect of physicochemical properties and mix ratios of iron ore (oxide feed): coke (reductant) on the carbothermic reductions of iron ore. Coke size was fixed at ≤63 ㎛ while iron ore size varied between 150-63 ㎛ and ≤63 ㎛ respectively. Mix ratios were changed from 100:0 (reference) to 80:20 and 60:40 while the temperature, heating rate and soaking duration in muffle furnace were fixed at 1100 ℃, 10 ℃/min and 1 hour. Particle size analyzer, XRF, CHNS and XRD analyses were used for determination of raw feed characteristics. The occurrence of phase transformations from various forms of iron oxides to iron during the carbothermal reductions were identified through XRD profiles and supported with weight loss (%). XRF analysis proved that iron ore is of high grade with 93.4% of Fe₂O₃ content. Other oxides present in minor amounts are 2% Al₂O₃ and 1.8% SiO₂ with negligible amounts of other compounds such as MnO, K₂O and CuO. Composite pellet with finer size iron particles (≤63 ㎛) and higher carbon content of 60:40 exhibited 45.13% weight lost compared to 32.30% and 3.88% respectively for 80:20 and 100:0 ratios. It is evident that reduction reactions can only occur with the presence of coke, the carbon supply. The small weight loss of 3.88% at 100:0 ratio occurs due to the removal of moisture and volatiles and oxidations of iron ore. Higher carbon supply at 60:40 leads into better heat and mass transfer and diffusivity during carbothermic reductions. Overall, finer particle size and higher carbon supply improves reactivity and gas-solid interactions resulting in increased reductions and phase transformations.

• Journal of the Korean Home Economics Association
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• v.27 no.2
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• pp.75-83
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• 1989

In this study, effect of heat treatment on phytic acid, phosphorus compounds, and minerals in Korean soybean varieties was investigated. Results were summarized as follwo: 1. In the soybeans tested, protein content ranged from 34.6 to 44.6%, lipid content from 15.4 to 20.2%, fiber content from 4.8 to 6.1% and ash content from 4.5 to 5.9%. 2. Content range for phytic acid in soybean varieties was 1,300 to 1,542mg/100g and its mean was measured 1,392mg/100g. With increasing of the temperature, the phytic acid tends to be destroyed, especially at 6$0^{\circ}C$ the loss was averaged about 20%. 3. Total phosphorus content in soybean ranged from 607 to 681mg/100g and the decending order of phosphors content in soybean varieties was Millyang > Hwangkeum > Kwangkyo > Danyoup > Hill > Jangyoup. It was also destroyed with increasing temperature. 4. Phytate phosphorus content range in soybean was from 315.6 to 318.0mg/100g and decreased with increasing temperature. 5. Inorganic phosphorus content ranged from 95.5 to 110.0mg/100g and it was increased by temperature rising among soybean varieties. 6. Phytate phosphorus to total phosphorus ratio ranged from 5.2 to 5.7 and decreased by temperature rising. 7. The content of nonphytate phosphorus varied widely between soybean varieties and decreased with temperature increase. 8. The content of calcium, iron and magnesium ranged from 15.7 to 25.7mg/100g from 8.8 to 16.8mg/100g and from 121.9 to 143.6mg/100g respectively. The content of Mg showed small difference among soybean varieties. The change of mineral content with heat treatment in soybean did not give any meaningful change mineral content.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1383-1389
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• 2011

The current study focuses on the consistent analysis of heat transfer in multichannel volumetric solar receivers used for concentrating solar power. Changes in the properties of the absorbing material and channel dimensions are considered in an optical model based on the Monte Carlo ray-tracing method and in a one-dimensional heat transfer model that includes conduction, convection, and radiation. The optical model results show that most of the solar radiation energy is absorbed within a very small channel length of around 15 mm because of the large length-to-radius ratio. Classification of radiation losses reveals that at low absorptivity, increased reflection losses cause reduction of the receiver efficiency, notwithstanding the decrease in the emission loss. As the average temperature increases because of the large channel radius or small mass flow rate, both emission and reflection losses increase but the effect of emission losses prevails.

• Korean Journal of Veterinary Research
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• v.59 no.2
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• pp.59-67
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• 2019

We investigated whether ${\beta}$-carotene (${\beta}-CA$) or ellagic acid (EA), originating from various fruits and vegetables, has a preventive effect against male infertility induced by exogenous scrotal hyperthermia. ICR adult mice were intraperitoneally treated with 10 mg/kg of ${\beta}-CA$ or EA daily for 13 days consecutively. During this time, mice were subjected to transient scrotal heat stress in a water bath at $43^{\circ}C$ for 20 min on day 7, and their testes and blood were obtained on day 14 for histopathologic and biochemical analyses. Heat stress induced significant testicular weight reduction, germ cell loss and degeneration, as well as abnormal localization of phospholipid hydroperoxide glutathione peroxidase (PHGPx) and manganese superoxide dismutase (MnSOD) in spermatogenic and Leydig cells. Heat stress also altered the levels of oxidative stress (lipid peroxidation, SOD activity, and PHGPx, MnSOD, and $HIF-1{\alpha}$ mRNAs), apoptosis (Bax, Bcl-xL, caspase 3, $NF-{\kappa}B$, and $TGF-{\beta}1$ mRNAs), and androgen biosynthesis (serological testosterone concentration and $3{\beta}$-hydroxysteroid dehydrogenase mRNA) in testes. These changes were all improved significantly by ${\beta}-CA$ treatment, but only slightly improved by EA treatment. These findings indicate that ${\beta}-CA$, through modulations of oxidative stress, apoptosis, and androgen biosynthesis, is a potent preventive agent against testicular injuries induced by scrotal hyperthermia.

• Journal of the Korean Wood Science and Technology
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• v.32 no.1
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• pp.73-79
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• 2004

Research investigated the variation of density, weight loss and dimensional decreasing rate, heat conduction rate by the resin impregnation rate and burning temperature of woodceramics, which were formed by impregnation rate of 40~80% and burning temperature of 600~1500℃ with sawdust board impregnated with phenolic resin made from thinned logs of pinus densiflora, Larix kaemferi and pinus koraiensis. As the resin impregnation rate and the burning temperature increased, the density increased, however, as the burning temperature increased to at 1200℃ or more, the density decreased. The more the resin impregnation rate increased, the more the decreasing rate of weight and size decreased; the more the burning temperature increased, the more the decreasing rate of weight and size increased. When the resin impregnation rate was high, the heat conduction (mm/sec) was superior.

• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.208-213
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• 2013

In this study, the effect of phosphorus flame retardants on the flame retardancy of the flexible polyurethane foam (PUF) was investigated. Tetramethylene bis(orthophosphorylurea) [TBPU] and phosphinyl alkylphosphate ester [CR-530], resorcinol bis diphenylphosphate [RDP], triethyl phosphate [TEP] were used as flame retardants. The results of thermogravimetric analysis (TGA) indicate that TBPU added PUF produces more charred residues than the other flame retardant added PUF. It was found that TBPU added PUF exhibits low mean heat release rate (HRR), peak HRR, effective heat of combusion (EHC), mass loss rate (MLR), CO yield and $CO_2$ compared to those other flame retardants.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.4
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• pp.347-355
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• 1994

Thin films of $PbTiO_3$ were deposited on bare silicon wafers by the sol-gel process. Heat treatment of films was executed at temperature range from $400^{\circ}C$ to $750^{\circ}C$ to investigated its effect on the crystal structure and element distribution of $PbTiO_3$films. Only the perovskite structure was observed in the films annealed at $440^{\circ}C$ but pyrochlore structure was partially found at temperature range from $480^{\circ}C to 550^{\circ}C$. Thin films annealed at temperatures higher than $600^{\circ}C$ showed only the perovskite structure again but also showed the increasing loss of lead.