• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.2 no.2
• /
• pp.84-90
• /
• 2003

Magnesium alloys have been paid attention In automotive and industries as lightweight materials, and with these materials it has been attempted at deep drawing process for assessment of formability of sheet metal. For warm deep drawing process with a local heating and cooling technique, both die and blank holder were heated at warm temperature while the punch was kept at room temperature by cooling water. Warm deep-drawing process with considering heat transfer was simulated by finite element method to investigate the improvement of deep-drawability and temperature distribution of Mg alloy sheet. The effect of sham rate sensitivity index on the deformation profile was considered in this work and the simulation results revealed that considering heat transfer is very effective for deep-drawability of Mg alloy. The deformed blank In considering heat transfer was drawn successfully without any localized thinning and the cup height is higher in contrast to results of simulations in considering no heat transfer.

• Journal of Welding and Joining
• /
• v.18 no.3
• /
• pp.76-82
• /
• 2000

In this study, three-dimensional heat flow in laser beam welding for deep penetration was analyzed by using F.E.M common code, and then the results were compared with the experimental data. The models for analysis are full penetration welds and are made at three different laser powers (6, 9.9, 4.5 kW) with two different welding speeds (5.8mm/s, 5mm/s). The characteristics of thermal absorption by the workpiece during deep penetration laser welding can be represented by a combination of line heat source through the workpiece and distributed heat source at the top surface due to the plasma plume above the top surface. This gives an insight into the way in which the beam interacts with the material being welded. The analyses performed with the combined heat source models show comparatively good agreement between the experimental and calculated melt temperature isotherm, i.e, the fusion zone boundary. The results are used to explain the "nail head" appearance of fusion zone, which is quite common in laser beam welds.eam welds.

• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.5 no.2
• /
• pp.1-9
• /
• 2007

Purpose: The purpose of this study was to investigate influence of superficial heat and deep heat for lumbo-sacral segment on H-reflex. Methods: Subjects of this research were 12 normal men and women (6 men and 6 women) and they were assigned to superficial heat group (6) and deep heat group (6). Heat treatment was applied between Th12-L2 by placing them at prone posture. superficial heat was applied for 20 min at 30 cm height with infrared lamp. Deep heat was applied for 20 mm at 5 cm height with 100 watt of microwave diathermy. H-reflex used diagnostic electromyography, active electrode was placed at muscle belly of medial gastrocnemius muscle at prone posture and electrical stimulation was given to posterior tibial nerve. Measurement was made before and after experiment and 10 min. and 20 min. after experiment. All data were analyzed with window 12.0 program, comparison of differences among measured items of groups according to repeated measurement was made with repeated measures ANOVA and significance level a was 0.05. Results: M latency at latency analysis showed little changes at two groups. H latency was reduced a little immediately after experiment and recovered to original state, there was significant difference. In analysis of amplitude, Mmax amplitude showed rise a little immediately after.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.46 no.6
• /
• pp.50-57
• /
• 2009

In this paper, a deep-heating stimulation system and protocol were designed to substitute the heat effect of moxibustion. Moxibustion is used to increase immunity and cure disease. But, it is difficult to control power of heat stimulation. A designed deep-heating stimulation system using Radio-Frequency(RF) is easy to control power of heat stimulation. Also, the stimulation protocol for substitution of the heat effect of moxibustion is proposed. Core temperature was applied to infrared camera, thermometer, and infrared sensor, and then was compared with that of moxibustion. The proposed system showed that it is more effective than moxibustion in transferring heat effect in such a deep part. Also, it shows the possibility of usefulness of deep-heating stimulation system and heat stimulation protocol.

• Journal of Oral Medicine and Pain
• /
• v.41 no.4
• /
• pp.195-199
• /
• 2016

Central sensitization represents a functional change of second order neuron induced by continuous deep pain input and maintained by psychosocial factors. When afferent neurons are involved with central sensitization, secondary hyperalgesia can appear. Secondary hyperalgesia is an increased sensitivity to stimulation without a local cause. Reports on secondary hyperalgesia to heat stimuli are relatively rare compared to mechanical stimuli. And there were few reports of secondary hyperalgesia to heat stimuli in the oral cavity. We presented a case of secondary hyperalgesia to heat stimuli in the gingival area induced by continuous odontogenic pain with a review of the related literature.

• CELLMED
• /
• v.12 no.4
• /
• pp.16.1-16.2
• /
• 2022

Treatment of patients with pain is directed at relieving pain and restoring function. Heat therapy has been used as a pain treatment. The mean temperatures were 40 and 41℃. Our device, Dr.Pakk heats special silicone to 41℃ with far-infrared rays and attaches it to the painful knee using a vacuum to show the effect. The core technology of the Dr.Pakk is that deep heat is generated when the heat is transmitted deeply by attaching it to the skin. In our experience, Dr.Pakk can be especially effective for knee pain.

• Nuclear Engineering and Technology
• /
• v.54 no.8
• /
• pp.2819-2827
• /
• 2022

The disposal area of a deep geological repository (DGR) for the disposal of spent nuclear fuels (SNFs) is estimated considering the spacing between deposition holes and between disposal tunnels, as determined by a thermal analysis using the decay heat of a reference SNF. Given the relatively large amount of decay heat of the reference SNF, the disposal area of the DGR is found to be overestimated. Therefore, we develop a computer program using MATLAB, termed ACom (Assembly Combination), to combine SNFs when stored in canisters such that the decay heat per canister is evenly distributed. The stability of ACom was checked and the overall distribution of the decay heat per canister was analyzed. Finally, ACom was applied to disposal scenarios suggested in the conceptual design of a DGR for SNFs, and it was confirmed that the decay heat per canister could be evenly distributed and that the maximum decay heat of the canister could be much lower than that of a canister estimated using a reference SNF. ACom can be used to improve the disposal efficiency by reducing the disposal area of a DGR for SNFs by ensuringg a relatively even distribution of decay heat per canister.

• Journal of Institute of Convergence Technology
• /
• v.7 no.1
• /
• pp.1-6
• /
• 2017

The Heat exchanger for deep geothermal system is very important to enhance the efficiency of the system. The co-axial heat exchanger is used due to the limitation of digging space. The heat transfer on the external surface of outer pipe should be high to receive a large amount of heat from the ground. However, the inner pipe should be insulated to reduce the heat loss and increase the temperature of discharge water. This study made experiment apparatus to describe the co-axial heat exchanger and measure the heat transfer coefficients on the internal and external surface. And the pin-fin was designed and fixed on the internal surface to increase the efficiency of heat exchanger. Finally, we calculated the temperature of discharge water using the heat transfer circuit of co-axial heat exchanger and heat transfer coefficient which from experimental results. The water temperature was reached the ground temperature at -500 m and following the ground temperature. When the water return to the ground surface, the water temperature was decreased due to heat loss. As the pin-fin case, the heat transfer coefficient on the internal surface was decreased by 30% and it mean that the pin-fin help to insulate the inner pipe. However, the discharge water temperature did not change although pin-fin fixed on the inner pipe.

• Nuclear Engineering and Technology
• /
• v.56 no.7
• /
• pp.2610-2624
• /
• 2024

Liquid metal heat pipes play a critical role in various high-temperature applications, with their optimization being pivotal to achieving optimal thermal performance. In this study, a deep learning based genetic algorithm is suggested to optimize the operating conditions of liquid metal heat pipes. The optimization performance was investigated in both single and multi-variable optimization schemes, considering the operating conditions of heat load, inclination angle, and filling ratio. The single-variable optimization indicated reasonable performance for various conditions, reinforcing the potential applicability of the optimization method across a broad spectrum of high-temperature industries. The multi-variable optimization revealed an almost congruent performance level to single-variable optimization, suggesting that the robustness of optimization method is not compromised with additional variables. Furthermore, the generalization performance of the optimization method was investigated by conducting an experimental investigation, proving a similar performance. This study underlines the potential of optimizing the operating condition of heat pipes, with significant consequences in sectors such as high temperature field, thereby offering a pathway to more efficient, cost-effective thermal solutions.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2008.05a
• /
• pp.556-559
• /
• 2008

In this study, the failure in circular cup deep drawing simulation at warm temperature is predicted using forming limit diagram (FLD). The FLD is used in sheet metal forming analysis to determine the criterion for fracture prediction. The simulation with heat transfer of circular cup deep drawing at warm temperature was conducted. To predict the failure, the simulation with heat transfer used FLD at temperature in the vicinity of maximum thinning. The result of the simulation with heat transfer shows that the drawn depth increases with increasing temperature and is in accord with the experimental results above $150^{\circ}C$. The FLD provides a good guide for the failure prediction of warm forming simulation with heat transfer.