• 한국식품영양학회지
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• 제27권1호
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• pp.112-119
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• 2014

Ohmic heating uses electric resistance heat which occurs equally and rapidly inside food when the electrical current is transmitted into. Prior to the study, we have researched the potato starch's thermal property changes during ohmic heating. Comparing with conventional heating, the gelatinization temperature and the range of potato starch treated by ohmic heating are increased and narrowed respectively. Herein, we have studied thermal property changes of wheat, corn, potato and sweet potato starch by ohmic heating as well as conventional heating. And then we measure the water holding capacity of starches. Annealing of starch is a heat treatment method heated at 3~4% below the gelatinization point. This treatment changes the starch's thermal property. In the DSC analysis of this study, the $T_o$, $T_p$, $T_c$ of all starch levels have increased, and the $T_c$-$T_o$ narrowed. In the ohmic heating, the treatment sample is extensively changed but not with the conventional heating. From the ohmic treatment, increases from gelatinization temperature are potato ($8.3^{\circ}C$) > wheat ($5.3^{\circ}C$) > corn ($4.9^{\circ}C$) > sweet potato ($4.5^{\circ}C$), and gelatinization ranges are potato ($7.9^{\circ}C$), wheat ($7.5^{\circ}C$), corn ($6.1^{\circ}C$) and sweet potato ($6.8^{\circ}C$). In the case of conventional treatment, water holding capacity is not changed with increasing temperature but the ohmic heating is increased. Water holding capacity is related to the degree of gelatinization for starch. This result show that when treated with below gelatinization temperature, the starches are partly gelatined by ohmic treatment. When viewing the results of the above, ohmic treatment is enhanced by heating and generating electric currents to the starch structure.

• 열처리공학회지
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• 제26권5호
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• pp.233-240
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• 2013

Rapid and homogeneous heating in heat treatment has been a challenging engineering issue throughout a heating temperature over $1,000^{\circ}C$. Induction heating has been widely used in field of heat treatment compared with conventional heating system. Advantages in homogeneous heating, simple fabrication, and repeatable use can be efficiently made with the induction heater. In this paper, numerical analysis of an induction coil system for heat flux gauge heating is performed. The effect of configuration on the heating performance was considered in various cases of the coil radius, distance between the winding, relative height difference between the heat flux gauge and the coil, and the applied current frequency. Temperature distribution within the heat flux gauge at frequency-steady state was calculated with a finite element method. Sensitivity analysis was also performed and the relative importance of 2 key parameters; coil radius, distance between the winding, were taken as main contributors for induction heating.

• 한국농공학회논문집
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• 제47권6호
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• pp.73-82
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• 2005

This study was performed to evaluate the need for heating wastewater to enhance treatment efficiency of organic matter (BOD, SS) during cold winter in newly developed Absorbent Biofilter System (ABS) which was established in the Suwon Campus of the Seoul National University. Treatments consisted of non-heating (2000 year) and heating(2001, 2002 year), and sampled data were analyzed during cold winter period as well as post winter period to investigate the influence of heating after winter season. Even the average air temperature showed only $0.4^{\circ}C$ difference between two experimental years, the difference in the average effluent temperature during cold winter period between heating and non-heating experiment was approximately $11^{\circ}C$. The average effluent concentration of organic matter in non-heating treatment exceeded the Korean standards for water quality of discharged effluent in riparian area (BOD and SS 10 mg/L); however, the standards were met in case of heating treatment during both winter and post winter period. Therefore, the need fur heating wastewater during cold winter season in ABS was justified. On the other hand, there was no improvement of treatment efficiency in T-N and T-p, but we observed the more activated nitrification as increasing the wastewater temperature. Because the average underground temperature was $5^{\circ}C$ higher than the average air temperature during cold winter period, we recommend that the ABS can be established in the underground rather than on-ground for saving the heating cost.

• 소성∙가공
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• 제27권2호
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• pp.87-92
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• 2018

Auto industries have tried to employ lightweight alloys to improve the fuel efficiency of manufactured vehicles, as the environmental concern becomes an important issue. Even though the aluminum alloy is one of the most appropriate lightweight alloys for auto parts, the low formability of an aluminum alloy has been an obstacle to its application. In order to resolve the low formability problem, a recent study (Lee et al., 2017 [1]) showed that the infrared (IR) local heat treatment can improve the formability with a reduction of heating energy. However, the aforementioned study was limited to only a linear line heating. Since many of the available auto parts as applicable to vehicle manufacturing have a curved line shape, the heating experiments for a curved line should be studied. The possibility of building IR lamps having complex shapes is an advantage of the IR lamp, since it can control the heating shape. This work conducted the IR local heat treatment for the curved line. The experimental results show that the IR local heat treatment can improve the formability of the aluminum alloy for curved line. Additionally, it is shown that the IR local heat treatment also reduces the heating energy when it is compared with the furnace heating which heats a blank as a whole. A numerical simulation with a stress-based forming limit diagram also supports the experimental results.

• 한방재활의학과학회지
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• 제20권3호
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• pp.109-117
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• 2010

Objectives : The purpose of this study is to investigate the clinical effects of heating-conduction acupuncture therapy on lumbago induced by iliolumbar ligament sprain. Methods : From September 25 to December 30, 2009, the 8 outpatients who had admitted to department of oriental rehabilitation medicine, Dae-Jeon oriental medical hospital, Dae-Jeon university, with acute lumbago were performed heating-conduction acupuncture therapy on iliolumbar ligament sprain. To evaluate the efficiency of heating-conduction acupuncture therapy, visual analogue scale(VAS) and short-form McGill pain questionnaire(SF-MPQ) were applied before treatment and after 1st, 2nd treatment. Results : 1.The VAS and SF-MPQ scores showed statistically significant improvement after 1st treatment. 2. The VAS and SF-MPQ scores after 2nd treatment showed better improvement than those of before and 1st treatment, but had no statistical significance compared with those of before and 1st treatment. Conclusions : Heating-conduction acupuncture therapy has clinical effects of pain reduction on patient with acute lumbago induced by iliolumbar ligament sprain.

• 한국농공학회논문집
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• 제48권5호
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• pp.51-60
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• 2006

In order to examine the heat transfer characteristic of a soil warming system and effects of soil warming on the greenhouse heating load, control experiments were performed in two greenhouses covered with double polyethylene film. One treated the soil warming with an electric heat wire and the other treated a control. Inside and outside air temperature, soil temperature and heat flux, and heating energy consumption were measured under the set point of heating temperature of $5,\;10,\;15,\;and\;20^{\circ}C$, respectively. Soil temperatures in a soil warming treatment were observed $4.1\;to\;4.9^{\circ}C$ higher than a control. Heating energy consumptions decreased by 14.6 to 30.8% in a soil warming treatment. As the set point of heating temperature became lower, the rate of decrease in the heating energy consumptions increased. The percentage of soil heat flux in total heating load was -49.4 to 24.4% and as the set point of heating temperature became higher, the percentage increased. When the set point of heating temperature was low in a soil warming treatment, the soil heat flux load was minus value and it had an effect on reducing the heating load. Soil heat flux loads showed in proportion to the air temperature difference between the inside and outside of greenhouse but they showed big difference according to the soil warming treatment. So new model for estimation of the soil heat flux load should be introduced. Convective heat transfer coefficients were in proportion to the 1/3 power of temperature difference between the soil surface and the inside air. They were $3.41\;to\;12.42\;W/m^{2}^{\circ}C$ in their temperature difference of $0\;to\;10^{\circ}C$. Radiative heat loss from soil surface in greenhouse was about 66 to 130% of total heating load. To cut the radiation loss by the use of thermal curtains must be able to contribute for the energy saving in greenhouse.

• Journal of Biosystems Engineering
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• 제37권6호
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• pp.429-433
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• 2012

Purpose: While rapeseed oil, soy bean oil, palm oil and waste cooking oil are being used for biodiesel, the viscosity of them should be lowered for fuel. The most widely used method of decreasing the viscosity of vegetable oil is to convert the vegetable oil into fatty acid methyl ester but is too expensive. This experiment uses ultrasonic energy, instead of converting the vegetable oil into fatty acid methyl ester, to lower the viscosity of the waste cooking oil. Methods: For irradiation treatment, the sample in a beaker was irradiated with ultrasonic energy and the viscosity and temperature were measured with a viscometer. For heating treatment, the sample in a beaker was heated and the viscosity and temperature were measured with a viscometer. Kinematic viscosity was calculated by dividing absolute viscosity with density. Results: The kinematic viscosity of waste cooking oil and cooking oil are up to ten times as high as that of light oil at room temperature. However, the difference of two types of oil decreased by four times as the temperature increased over $83^{\circ}C$. When the viscosity by the treatment of ultrasonic energy irradiation was compared to one by the heating treatment to the waste cooking oil, the viscosity by the treatment of ultrasonic energy irradiation was lower by maximum of 22% and minimum of 12%, than one by the heating treatment. Conclusions: Ultrasonic energy irradiation lowered the viscosity more than the heating treatment did, and ultrasonic energy irradiation has an enormous effect on fuel reforming.

• 한국산업융합학회 논문집
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• 제5권4호
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• pp.361-366
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• 2002

The change of mechanical properties of drawn PP filaments which was treated by isothermally annealed after elevated heating. Measurements were carried out with UTM for mechanical properties. Isothermally heat treatment were carried out $100^{\circ}C$, $120^{\circ}C$, $140^{\circ}C$ for 10min., 30min., 60min, in silicon oil bath. And isothermally heat treatment after elevated heating from $20^{\circ}C$ were carried out $100^{\circ}C$, $120^{\circ}C$, $140^{\circ}C$ for 10min., 30min., 60min., with heating rate of $1^{\circ}C/min$., $5^{\circ}C/min$., $10^{\circ}C/min$. From the results of this study, it found the following facts. Initial modulus and tensile strength were increased with increasing of annealed temperature and time. Also initial modulus of tensile strength of samples which were isothermally annealed after elevated heating from $20^{\circ}C$ were higher than those of isothermally annealed samples.

• Toxicological Research
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• 제14권3호
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• pp.301-306
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• 1998

This experiment was carrid out to know the effects of heating and serum on hydroxyl radicals in embryonic mouse forebrain (cerebrum) culture. The heating to mouse embryonic cerebrum cells in culture was done in a water bath at 43${\circ}C$ for 60min. After that, two supernatants were prepared at 20 hrs and 48 hrs respectively after heat treatment to the brain cells. To find out the heating effects on neuron cells, mouse cerebrum cells (13 embryonic day) were cultured in hydroxyl radical generation system composed of 20mU/ml glucose oxidase (GO system), using condition of normal culture media (MEM, 5% serum, 5% $CO_2$or supernatant prepared after heating at 43${\circ}C$ for 60 min in a water bath. Supernatant prepared at 20 hrs after heat treatment had a greater protective effects against hydroxyl radical than supernatant prepared at 48 hrs after heat treatment . Otherwise, the protective effect of serum against hydroxyl radicals in the cultured brain cells is higher than that in the heat treatment. These results indicated that serum in culture media reduced cytotoxicity of hydroxyl radicals in mouse forebrain culture, also that heat treatment showed the protective effects against hydroxyl radicals generated with 20mU/ml GO system in mouse forebrain culture.

• 한국식품영양과학회지
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• 제24권2호
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• pp.234-241
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• 1995

Effect of microwave heating on the oxidative stability of the soybean oil, sesame oil, butter and margarine were investigated by mearsuring fatty acids amout and tocopherol losses. The index for chemical properteis, free fatty acid, peroxide value, anisidine value, carbonyl value, conjugated diene and triene levels were also mearsured in the oil samples for 5, 10, 15 and 20 min of heating in a microwave oven. No significant difference was observed on the fatty acids composition in the fats and oils before and after microwave heating. During microwave treatment, the oxidative degradation of the tocopherols in the samples became greater with increasing heating time. The amount of tocopherols in the soild fats, butter and margarine, dropped drastically after 5 min of heating and reduced to 95% of their original levels after 20min heating ${\gamma}$-tocopherol in butter showed the most unstable states and completely destroyed during microwave treatment for 20min. On the other hand, 80% of tocopherols in the liquid oils were still remained after 5min of heating except $\delta$-tocopherol in sesame oil.