• Korean Journal of Food Science and Technology
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• v.18 no.6
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• pp.437-442
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• 1986

Physicochemical properties of chestnut starch, which was adjusted at 14, 18, 21 and 24% moisture and heated for 16 hr at $100^{\circ}C$, were investigated. The cystallinity, swelling power and solubility of the starch were decreased upon heat-moisture treatments. The swelling power of the heat-moisture treated starch showed an inverse relation with moisture levels, while the solubility showed opposite trend. The swelling power and the solubility of both raw and heat-moisture treated starches held a liner relationship. The. water binding capacity of the starch was drastically increased upon heat-moisture treatments. Amylograms revealed that the heat-moisture treated starches had higher initial pasting temperature and lower viscosity than untreated starch. No peak viscosity was observed for the heat treated starches above 21% moisture. The minimum moisture contents for gelatinization of raw and heat-moisture (18%) treated starches were 45 and 40%, respectively. The gelatinization temperature of raw and heat-moisture (18%) treated starches was $65^{\circ}C$.

• Journal of the Korean Wood Science and Technology
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• v.46 no.3
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• pp.285-296
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• 2018

As a study for the verification of heat treated wood according to ISPM No. 15, the spectroscopic characteristics of the heat treated wood surface were analyzed. Various functional groups were observed on the IR spectrum, but it was difficult to find any particular difference between wood species, heat treatment time and storage period. HBI (hydrogen-bonding intensity) shows the change of the heat treated wood according to the storage time, but the change of wood with the heat treatment time was hard to be observed. On the PCA score plot, however, it was possible to sort the wood according to the heat treatment time of 60 minutes or 90 minutes in the species. The standards for classification of heat-treated wood in PCA were aromatic rings in lignin and C-H bending in cellulose, and these components were able to classify heat-treated wood by ISPM No. 15.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.299-303
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• 2008

The treated sewage temperature is about $5^{\circ}C$ lower in summer and $5{\sim}10^{\circ}C$ higher in winter than ambient air. It can be used heat pump heat source and is good heat source on high performance of heat pump. In this study, to develop 100RT 2-stage compression heat pump use treated sewage water heat source and system applies to sewage disposal plant. Although heat pump is better performance, the large temperature difference between load and source makes the performance degradation of a heat pump. To solve this problem screw 2-stage compression is considered. The experiment was focused on the system operating performance variations over supply water and treated sewage water a temperature in the field. The results show that system of heating performance is higher then general heat pump and is enough to supply a hot water of $70^{\circ}C$.

• Journal of Ocean Engineering and Technology
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• v.27 no.2
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• pp.69-74
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• 2013

In this study, the crack healing effects of $Al_2O_3$ ceramics based on the heat treatment conditions were investigated. The influence of the additive amounts of SiC nanoparticles and the cycling process of indentation-heat treatment on the crack healing effect of $Al_2O_3$ ceramics were also examined. Three-point bending tests were carried out and the morphological changes in the fracture surface were observed by using FE-SEM. As a result, heat-treated samples in a vacuum or air atmosphere showed improved bending strengths compared to un-heat treated samples. This means that cracked specimens can be healed by heat treatment in a vacuum or air atmosphere. The crack healing effect of $Al_2O_3$ ceramics that were heat treated in an air atmosphere was much higher than that of those heat treated in a vacuum. After heat treatment, the $Al_2O_3$ ceramics with 30 wt% SiC nanoparticles showed a higher bending strength than those with 15 wt% SiC. The cyclic indentation and heat treatment did not remarkably affect the crack healing effect. The SEM images showed that the median crack, indenter mark on the surface, and pores in the fracture surface of a specimen almost disappeared after being heat treated in an air atmosphere.

• Journal of the Korean Wood Science and Technology
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• v.38 no.1
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• pp.17-26
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• 2010

Recently, yellow poplar (Liriodendron tulipifera L.) is getting attention in Korea due to the fast growing and high yield and quality of lumber. But, it is thought that the color difference between heartwood and sapwood may restrict the practical use of it. This study was aimed to enhance the value of yellow poplar lumber by the color control using high temperature heat-treatment, which had been tried for domestic cedar (Kim et al., 2009). The material properties including surface color of yellow poplar lumber were evaluated according to heat treatment conditions. The difference of color between sapwood and heartwood could be reduced by heat treatment at a temperature about $200^{\circ}C$. Long heating time was more effective in reducing the difference. The Equilibrium Moisture Content (EMC) of heat-treated wood was as low as 50 percent of the control. The result obviously indicates that heat-treated wood is more dimensionally stable in the change of moisture condition. The durability against wood rotting fungi also increased by the heat-treated, but it was not so effective as the case of cedar. The changes of mechanical properties of heat-treated yellow poplar were very similar to that of heat-treated cedar. In order to develop new use of heat-treated yellow poplar, the changes of mechanical properties should be considered. There were no significant changes in microscopic structure which may cause changes in mechanical properties. Further study of heat-treated wood is needed to scrutinize the causes of changes of material properties.

• Journal of the Korean Society for Heat Treatment
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• v.26 no.1
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• pp.7-13
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• 2013

Vacuum heat treatment(indirect heating method) has long exposure time at high temperature and low quenching rate. Contrarily salt bath heat treatment (direct heating method) has short exposure time at high temperature and fast cooling rate. With these different features of processes, mechanical properties such as hardness, tensile strength and impact strength of products show very different results. In this study, Salt bath heat treated products showed higher tensile strength and impact strength than vacuum heat treated products but hardness was not much different. These lower mechanical properties of vacuum heat treated products are due to differences in heat process and secondary hardening with high temperature tempering process. Consequently, It indicates that salt bath heat treatment is better way than vacuum heat treatment for product to have high mechanical properties.

• Composites Research
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• v.18 no.2
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• pp.38-45
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• 2005

Phase transformation behaviors and crystal structures of Nitinol shape memory alloy $(54.5Ni-45.5Tiwt\%)$ are investigated by varying annealing heat treatment conditions through DSC (Differential Scanning Calorimetry) and XRD (X-Ray Diffraction). Annealing heat treatment conditions were considered as heat treated times of 5min, 15min. 30m1n, and 45min, as well as heat treated temperatures of $400^{\circ}C,\;500^{\circ}C,\;525^{\circ}C,\;550^{\circ}C,\;575^{\circ}C,\;600^{\circ}C,\;700^{\circ}C,\;800^{\circ}C,\;and\;900^{\circ}C$ According to the results, annealing heat treatment conditions such as heat treated times and heat treated temperatures were found to affect significantly on phase transformation behaviors and crystal structures of Nitinol shape memory alloy.

• Transactions of Materials Processing
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• v.18 no.2
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• pp.116-121
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• 2009

Formability and other mechanical properties of sheet metals are strongly dependent on the texture. It was studied to improve the formability of the Al alloy(AA3003) sheets which were rolled under the non-lubrication condition and subsequent heat treated. In the non-lubrication rolled and subsequent heat treated Al alloy sheet, the variation of the plastic strain ratios were investigated in this study. Non-lubrication rolled Al sheets showed a fine grain size and after subsequent heat treated specimens showed that the $\beta$-fiber texture component was increased. The plastic strain ratios of the non-lubrication rolled and subsequent heat treated Al alloy sheets were about two times higher than those of the original Al sheets. These could be related to the formation of $\beta$-fiber texture components through the non-lubrication rolling and subsequent heat treatment in Al sheet.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.4
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• pp.419-426
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• 2011

In this study, an experimental and theoretical program were carried out to determine the cutting forces and chip formation at different cutting speeds using a 0.4mm nose radius ceramic insert and -7 rake angle for non heat-treated AISI 4140 (27HRc) and heat-treated AISI 4140 (45 HRc) steel. The results obtained were compared to show the hardness differences between the materials. The secondary deformation zone thicknesses when comparing the two materials show different physical structure but similar size. These results were also discussed in light of the heat treatment and the effects it had on the machining characteristics of the material. In addition, the Oxley Machining Theory was used to predict the cutting forces for these materials and a comparison made. The predicted cutting performances were verified experimentally and showed good agreement with experimental data.

• Journal of the Korea Furniture Society
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• v.19 no.6
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• pp.460-465
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• 2008

When wood is exposed to natural weathering and UV radiation discoloration progresses. The color variation of heat-treated wood was investigated. Four domestic species were selected and heat-treated at $220^{\circ}C$ and naturally weathered for 42 days. Their colors were measured with a portable colorimeter. The color variations were different between species. The Korean red pine specimens were highly discolored by the natural weathering even though they were heat-treated. In contrast to Korean red pine, Korean pine is less discolored. The maximum color difference of larch was lower than Korean red pine. All specimens of birch exceeded the color difference criterion of 15 after 25 hours with the maximum of 28.