• 동력기계공학회지
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• 제8권1호
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• pp.30-35
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• 2004

This paper represents the numerical analysis on effect of the environmental velocity for circular heating source with heat generation. In general heating system, the oil and sheath heater is widely used, but these systems have many problems. So, the heating source with carbon ingredient has been researched in many country about manufacture, thermal and electrical properties. In this research, a circular heating source was studied through numerical analysis on several conditions of unsteady state, beat generation and environmental velocity. The temperature distributions at steady state is appeared as a non-linear pattern with variations of environmental velocity. So, the correlation equation between temperature at steady state and environmental velocity was obtained.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.210-211
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• 2018

In this study, the ultrasonic pulse velocity of the concrete cooled to room temperature after heating and the concrete during heating were evaluated. Also, the ultrasonic pulse velocity and mechanical properties of concrete were compared. As a result, the ultrasonic pulse velocity decreased when the concrete degraded during heating, and the ultrasonic pulse velocity of the cooled concrete decreased significantly. Which is consistent with the deterioration of mechanical properties of concrete.

• 동력기계공학회지
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• 제10권4호
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• pp.25-30
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• 2006

This paper represents the numerical analysis in unsteady state on the variation of diameter and environmental velocity of carbon heating source. In general heating system, the oil and sheath heater is widely used, but these systems have many problems. So, the heating source with carbon ingredient has been researched in many country about manufacture, thermal and electrical properties. In this research, the carbon heating source was studied through numerical analysis on several conditions of unsteady state, heat generation, diameter and environmental velocity. The temperature distributions at steady state are appeared as a non-proportional linear pattern with variations of environmental velocity due to the Nesselt number with convective heat flux is proportioned to 0.805 of Reynolds number. As the radius is increasing, the temperature distributions is appeared the minus tilt because of the environmental condition is cooling by constant temperature. So, the correlation equation between temperature at steady state and environmental velocity was obtained.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.57-59
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• 2015

A method to measure heating value of natural gas using sound velocity and thermal conductivity is proposed to solve the low heating value issues of imported natural gas in South Korea. Natural gas generally consists of methane, butane, ethane, and inert gases. Heating value changes as the gas material properties, such as density, wobbe index, etc., varies. It is highly important to measure heating values of natural gases accurately because measuring the heating value depends on the given natural gases' components. Therefore, sound velocity and thermal conductivity is measured to estimate indirectly heating value of Natural gas with their changed components.

• 대한간호학회지
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• 제42권4호
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• pp.579-588
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• 2012

Purpose: The purpose of this study was to identify the effects of heating on the non-affected hand on blood flow velocity, wound healing, and pain for hand microsurgery patients. Methods: This study was designed using the nonequivalent control group pretest-posttest design. Thirty-nine patients were assigned either to the experimental group (20 patients) or control group (19 patients). Data were analyzed with $x^2$-test, Fisher's exact test, t-test, and repeated measure ANOVA using SPSS/WIN 17.0 program. Results: After treatment in this program, blood flow velocity (F=5.13, p=.008) and wound healing (F=4.11, p=.020) improved significantly in the experimental group compared to the control group. But there was no significant improvement in pain in the experimental group compared to the control group (F=2.40, p=.097). Conclusion: Based upon these results, the non-affected side hand heating was recommended as an independent nursing intervention for the patients who need improvement in blood flow velocity and wound healing such as patients who have microsurgery. As the heating was effective even when applied on the non-affected side, it is the applicable to patients who cannot tolerate any therapy on affected side.

• 한국정밀공학회지
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• 제19권6호
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• pp.136-144
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• 2002

Melting method has long been considered difficult to realize because of problems such as the low foamability of molten metal, the varying size of cellular structures and solidification shrinkage. The parameters to solve the problem in electric furnace were stirring temperature, stirring velocity, heating velocity and foaming temperature It is important to consider the effects of induction heating, because it brings about the inner flow by the temperature gradient. Aspect ratio also depends on the induction heating. Mechanical properties are dependent on cell sizes and aspect rations. Therefore, this paper presents the effects of these parameters on the cell sizes. For the sake of this, combined stirring process was used to fabricate aluminum foam materials by the above mentioned parameters. Image analysis was performed to calculate the cell sizes, distributions, and aspect ratioes at the cross section of feared aluminum in the direction of height.

• 한국의류산업학회지
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• 제18권5호
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• pp.716-723
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• 2016

The purpose of this study was to investigate the change in blood velocity(mm/sec) when compression and/or heat were applied to the knee joint for the elderly who has both normal and painful legs with osteoarthritis(OA). Experimental compression knee band was prepared from the 3D knee data of the average women in 60's. 3D replica of knee was reduced by 7, 10, and 13% from the nude pattern in course direction. Clothing pressure was measured at the front and back of each healthy and painful knee of elderly women for one minute while standing and sitting on the chair. Blood velocity was measured at 13 cm upper from the mid-patella for 15 minutes. Results are as follows: first, compression or heating treatment itself did not change blood velocity of both legs; second, combination treatment with heating and compression was effective to increase blood velocity. In details, for healthy legs, combination treatments with compression by 10% reduced pattern(about 1.3kPa) and heating($43^{\circ}C$) induced the maximal blood velocity, however, for knees with OA, 7% reduced pattern(about 1.0kPa) with simultaneous heating($43^{\circ}C$) was more effective than other cases. These results indicated that pain and spasticity of knee joint with OA could be reduced by applying heat and compression therapy, where the compression level of painful knee should be slightly lower than of healthy leg.

• 한국산업융합학회 논문집
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• 제24권4_2호
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• pp.467-474
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• 2021

The renewable energy is known as eco-friendly energy to reduce the use of fossil fuel and decrease the environmental pollution due to exhaust gas. Targets of solar collector in domestic are usually acquisitions of hot water and hot air. System of air-heating collector is one of the technologies for obtaining hot air in cases of especially heating room and drying agricultural product. The purpose of this study is to investigate the characteristics of thermal flow such as relative pressure, velocity, outlet temperature and buoyancy effect in air-heating collector using solar heat. The flow field of air-heating collector was simulated using ANSYS-CFX program and the behaviour of hot air was evaluated with SST turbulence model. As the results, The streamline in air-heating collector showed several circular shapes in case of condition of buoyancy. Temperature difference in cross section of outlet of air-heating collector did not almost show in cases of buoyancy and small inlet velocity. Furthermore merit of air-heating collector was not observed in cases of inlet velocities. Even though it was useful to select condition of buoyancy for obtaining high temperature, however, it was confirmed that the trade off between high temperature of room and rapid injection of hot air to room could be needed through this numerical analysis.

• 동력기계공학회지
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• 제17권3호
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• pp.28-34
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• 2013

This study is experimentally performed for using the oyster shell as a desiccant in the fluidized bed with bundle of heating pipe. The test material is oyster shell from fishery wastes which can use without costs. The main parameters of experiment are inlet air temperature, velocity of inlet air and heat flux of heating pipes. Also the geometry of heating pipe is treated as important parameter. From this study, the effect of inlet air temperature and input heat flux have much affect to increase the heat and mass transfer. On the other hand, the effect of inlet air velocity has less affect to increase the heat and mass transfer. And it is clarified that the oyster shell has sufficient probability for using as a desiccant in air-conditioning system.

• Nuclear Engineering and Technology
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• 제52권12호
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• pp.2771-2788
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• 2020

Experiments are conducted to study bubble flow behavior during the instability of subcooled boiling under uniform and non-uniform transverse heating. The non-uniform heat distribution introduces nonuniform bubble generation and condensation rates on the heated surface, which is different from the uniform heating. These bubble generation and condensation characteristics introduce a non-uniform local pressure distribution in the transverse direction, which creates an extra non-uniform pressure on the flowing bubbles. Therefore, different bubble flow behavior can be observed between uniform and non-uniform heating conditions. In the uniform heating, bubble velocity fluctuations are low, and the bubbles travel straight along the axial direction. In the non-uniform heating, more fluctuation in the bubble velocity occurs at low mass flow rate and high subcooled inlet temperatures, and reverse flow is observed. Additionally, the bubbles show a zigzag trajectory when they pass through the channel, which indicates the existence of cross flow in the transverse direction.