• Carbon letters
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• 제13권3호
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• pp.151-156
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• 2012

This study considered the effect of the heat treatment temperature on the compressive strength of coal powder compacts affected by density, porosity, and crystallinity. Coal powder compacts were made by pressing of milled coal powder and were heat treated at 200, 400, 600, 800, and $1000^{\circ}C$. The density and porosity of the heat treated specimens at each temperature were measured using the Archimedes method and changes in crystallinity were analyzed using Raman spectroscopy. Increases in compressive strength at $600^{\circ}C$ or higher temperatures were proportionally related to increases in the density and the degree of crystallinity.

• 한국주조공학회지
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• 제36권3호
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• pp.88-94
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• 2016

We investigated the effect of heat treatment on an ADC12 alloy produced using diecasting. The heat treatment used in this study was a typical T6 process: a solid solution treatment followed by an artificial aging treatment. As-cast specimens were solid-solution-treated at $500^{\circ}C$ and $530^{\circ}C$ for 1-16 hr, and aged at $160^{\circ}C$ and $180^{\circ}C$ for 1-8 hr. Microstructural changes in the alloy during the heat treatment were observed. Changes in mechanical properties of the alloy were measured using a micro-Vickers hardness tester. Finally, we determined the optimal heat treatment conditions for the diecast ADC12 alloy.

• 기술사
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• 제31권5호
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• pp.110-120
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• 1998

The effect of heat treatment and the order of antioxidants treatment toward the thermally oxidized palm oil which has been stored at 60 $^{\circ}C$ was studied. The summerized results of this study are as follows; 1. In the accelerated autoxidation condition, tocopherol showed no distinct effect on the changes of peroxide of value between added tocopherol samples pre-and post treatment by heating. But, rosemary extract showed opposite result. It was supposed that rosemary extract had lower thermostability then tocopherol, because rosemary extract lost it's antioxidative activity during heating process. 2. The changes of acid value and anisidine value were more affected by heat treatment than the order of antioxidant treatment. 3. The oxidative stability measured by OSI showed same tendency as peroxide value. That is, the antioxidative activity of tocopherol in palm oil was more dependent on addition of antioxidants than heat treatment, but the rosemary extract had opposite character for antioxidative action in palm oil.

• Asian-Australasian Journal of Animal Sciences
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• 제6권1호
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• pp.19-26
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• 1993

The effect heat treatment (autoclave) on nutritional value of winged bean as compared to soybean has been investigated. The winged bean and soybean were obtained from local cultivar grown in Indonesia. The beans were autoclaved at $120^{\circ}C$ for 15, 30, 45, 60 or 90 minutes, respectively before being ground for chemical analysis. Trypsin inhibitors of winged bean and soybean decreased (p < 0.05) along with decreasing of urease activity as heating time increased from 0 to 90 minutes. Heat treatment significantly (p < 0.05) reduced protein solubility in 0.2% potassium hydroxide of winged bean as well as soybean. In vitro protein digestibility was significantly (p < 0.05) improved by heating treatment (15 to 60 min of autoclaving), however, excessive heating (90 min of autoclaving) decreased the digestibility of winged beans. Excessive heating had adverse effect on lysine, cystine and methionine contents of winged beans. The results of this study suggested that autoclaving at $120^{\circ}C$ within 45 minutes should be adequate to remove protease inhibitors and could improve protein digestibility of winged beans.

• 대한치과교정학회지
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• 제22권3호
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• pp.591-602
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• 1992

The purpose of this study was to evaluate the effect of heat treatment on physical properties of 0.016' and 0.016' x 0.022' stainless steel wires. Temperature of heat treatment had intervals of $50^{\circ}C$ from $400^{\circ}C$ to $700^{\circ}C$, and time of heat treatment were 3, 6 and 9 minutes. Tensile tests were measured by ultimate tensile strength and yield strength. Bending tests were assessed by maximum bending force, recovery force, and stiffness. Torsion test was evaluated by torsion cycle until wires were fractured. The results were as follows: 1. In round wires, the highest value of ultimate tensile strength and yield strength were recorded of heat treatment at $500^{\circ}C$. In rectangular wires, the highest value of ultimate tensile strength were after 9 minutes at $400^{\circ}C,\;450^{\circ}C$ and 3, 6 minutes of heat treatment at $50^{\circ}C$, yield strength were the highest value after 3, 6 minutes of heat treatment at $500^{\circ}C$. 2. In both round and rectangular wires, maximum bending force and recovery force were the highest values after 6 minutes of heat treatment at $500^{\circ}C$. In round wires, highest value of stiffness were formed after 9 minutes at heat treatment at $500^{\circ}C$. In rectangular wires, the highest value of stiffness were for 6 minutes in $500^{\circ}C$. 3. In rectangular wires, torsion cycle was minimum after 6 minutes of heat treatment at $500^{\circ}C$. 4. In all of tension, bending, and torsion tests, the heat treated wires were softened over at $700^{\circ}C$. 5. In all of tension, bending, and torsion tests, physical properties of the wires were more influenced by the temperatures than the duration of the heat treatment.

• 열처리공학회지
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• 제5권3호
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• pp.171-178
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• 1992

The effect of nozzle characterristics on the mist-cooling heat transfer was investigated under the various flow conditions. Two different types of twin fluid nozzle were used, one is a $90^{\circ}$ angle tip nozzle with needle and the other is a $90^{\circ}$ angle tip non-needle nozzle. The cooling rate from the heated surface was measured and obtained the boiling curve as a function of surface temperature. An immersion sampling was employed for the measurement of droplet size of the spray. As a result of this experiment, the liquid sheet type nozzle shows better atomization when the mass ratio Mr>2.0, and collects more liquid droplets on the heated surface that results in better cooling effect. It was found that the maximum heat flux and heat transfer coefficient increased with increase in the volumetric flow rate, whereas the maximum heat flux decreased with increase in spray distance. The cooling effect depends upon the amount of collected droplet and droplet size, but it strongly depends upon the amount of collected droplet.

• 대한수의학회지
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• 제11권2호
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• pp.137-140
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• 1971

Survival and thermal inactivation after heat treatment at $143^{\circ}F$ were observed among 27 strains of coliform bacteria isolated from dairy cattle. The results obtained were as follows. 1. The obvious differences in heat-sensitivity were observed among the strains tested. 2. No strain was found resistant to the heat treatment of $143^{\circ}F$ for 30 minutes. 3. A marked effect of density of coliform bacteria on the survival after the heat treatment was observed. As the density of coliform bacteria was increased, the rate of survival was increased markedly regardless of the length of heat treatment.

• 열처리공학회지
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• 제13권1호
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• pp.21-26
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• 2000

This study deals with effects of heat-treatment on the fatigue strength of SNC815 spur gears. The test gears are heat-treated by two different treatments. After carburization, one group of the test gears is quenched directly, while the other group is fumace cooled, reheated then quenched. The fatigue test at a constant stress amplitude is performed by using an electrohydraulic servo-controlled pulsating tester. The S-N curves are obtained and illustrated. By comparing the estimated strength with the experimental results, the validity of the previous experimental formula, presented by the author for estimating the fatigue strength of carburized gears, was discussed on these tested gears.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.298-303
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• 2000

The 3 mol% yttria stabilized zirconia (3-Y PSZ) powder was heat treated at 50 0$^{\circ}C$ to evaporate the polymer binder and stabilize the tetragonal phase. The wear experiments were carried out on a ring-on-plate type reciprocating wear tester at selected temperatures with in the range room temperature to 600$^{\circ}C$ The results show that the heat treatment of powder decreases the wear rate due to the reduction of microcracks and pores in coatings and the stabilization of the tetragonal phase. Powder heat treatment enhanced the quality of the coating layer by removing remnant gases during coating process and the powder heat treatment at which tetragonal phase is stable diminished phase ratio of monoclinic. These two effects improved wear resistance characters.

• 열처리공학회지
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• 제16권6호
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• pp.356-363
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• 2003