• Architectural research
• /
• 제10권1호
• /
• pp.33-39
• /
• 2008

Condensation has mainly occurred in corridor type apartment door which is exposed to the outside air and is made of steel, which has high thermal conductivity. As a result, the total costs of repair have increased with the number of disputes with residents. In this study, therefore, we investigate materials and construction methods used in apartment door, perform a computer simulation to find out possible improvements, and then suggest the dew point to prevent the occurrence of condensation throughout simulation. The results indicate that the temperature that condensation does not occur is $15.4^{\circ}C$, and the optimum method of achieving this dew point is shown to be a door frame system including a large vertical slot to decrease the area of thermal conduction between the outer and inner portions of the door frame. Mock-up tests show that the surface temperature of the door frame was higher than the dew point, and the system can withstand severe cold conditions of $-20^{\circ}C$. In application test, the surface temperature of door frame with vertical slots is $5.9^{\circ}C$in average, which is higher than the existing door frame. Furthermore, in the temperature distribution of the surrounding door measured with infrared ray camera, the existing door shows the high temperature distribution indicating lack of insulation, but the improved door shows the low temperature distribution indicating higher insulation.

• 한국임상보건과학회지
• /
• 제9권1호
• /
• pp.1462-1468
• /
• 2021

Purpose; The purpose of this study is to objectively identify and quantify the wearer's feelings of wearing glasses. Methods: The temperature of the skin on the nose ridges and ear, and the area where the glasses were seated, was measured using a thermal imaging camera. Results: Before wearing the glasses, the temperature of the skin surface on the nasal ridge was 34.908 ± 0.875 ℃ and the temperature of the ear region was determined as 31.981 ± 0.549 ℃. The changed temperature measured at 5 minutes later after taking off the glasses showed that the nasal ridge was determined as 35.467 ± 0.342 ℃ and the ear area was determined as 32.994 ± 0.412 ℃ (p<0.05). Conclusions: In this experiment, it was revealed that the glasses cause discomfort and heat in the fitting area. It was the first attempt to study objectively and scientifically. Analysis of frame fitting points by using thermal camera is expected to be helpful when consulting a sensitive person about changes in the fit of glasses.

• 대한조선학회논문집
• /
• 제49권3호
• /
• pp.232-238
• /
• 2012

The effects of temperature on the structural behavior of polar class vessels have been experimentally and numerically investigated. Experiments were carried out on single frame structures made of steel material, DH36, which is used for outer shell of the vessels making transit through the polar region. A knife edge type striker was dropped down onto single frame structures. The temperatures of the single frames were set to $-30^{\circ}C$, $-50^{\circ}C$ and room temperature. The deflection around the mid-point of the single frame was measured and numerically simulated using finite element model. Strain rate effect on the structural behavior has been investigated and turned out that the strain rate effect can be neglected. From the results of the experiment and numerical analyses, it has been noticed that the permanent deflection at lower temperature was reduced due to a temperature hardening of material as expected.

• 한국생산제조학회지
• /
• 제21권2호
• /
• pp.259-266
• /
• 2012

In this study, the temperature distributions are analyzed on the air flow according to the position of fan inside computer main frame by CFD simulation. In case that ventilation hole is existed at the side of computer frame, the air with lower temperature can be circulated near CPU radiant thermal panel. In case of installation with fan at the side panel, the temperature of air flow becomes lowest. The efficiency of thermal emission at personal computer and its durability can be improved by releasing a lot of heat at air flow effectively inside computer frame according to this simulation result.

• 대한조선학회논문집
• /
• 제49권4호
• /
• pp.281-286
• /
• 2012

Single frame structures with notches were fractured by applying drop impact loadings at room temperature and low temperature. Johnson-Cook shear failure model has been employed to simulate the fractured single frame structures. Through several numerical analyses, material constants for Johnson-Cook shear failure model have been found producing the cracks resulted from experiments. Fracture strain-stress triaxiality curves at both room temperature and low temperature are presented based on the extracted material constants. It is expected that the fracture strain-stress triaxiality curves can offer objective fracture criteria for the assessment of structural fractures of polar class vessel structures fabricated from DH36 steels. The fracture experiments of single frame structures revealed that the structure on low temperature condition fractures at much lower strain than that on room temperature condition despite the same stress states at both temperatures. In conclusion, the material properties on low temperature condition are essential to estimate the fracture characteristics of steel structures operated in the Northern Sea Route.

• 대한설비공학회지:설비저널
• /
• 제17권4호
• /
• pp.357-368
• /
• 1988

An application of thermal response coefficient method for obtaining thermal load on stud-frame walls in a typical house is presented. A set of stud-frame walls is two-dimensional heat conduction transients with composite structure. The ambient temperature on the right-hand face of the stud-frame walls is a typical day-cycle input and the room temperature on the left-hand face is a constant input. The desired output is thermal load at the left-hand face. The time-dependent ambient temperature is approximated by a continuous, piecewise-linear function each having one hour interval. The conduction problem is spatially discretized as 8 computer modelings by finite elements to obtain thermal response coefficients. The discretization and round-off errors can be neglected in the range of adequate number of nodes. A 60-node discretization is recommended as the optimum model among 8 computer modelings. Several sets of response coefficients of the stud-frame walls are generated by which the rate of heat transfer through the walls or some temperature in the walls can be calculated for different input histories.

• 전자공학회논문지
• /
• 제53권8호
• /
• pp.113-118
• /
• 2016

본 논문에서는 30 Hz의 프레임률로 동작하는 적외선 영상 투사기 (IR scene projector, IRSP)에서 투사되는 적외선 영상의 유효온도 감소를 최소화하기 위해 sub-frame 제어 기법을 적용한 IRSP용 신호입력회로 (read-in integrated circuit, RIIC)를 제안한다. 제안하는 sub-frame 제어 기법은 단위 프레임을 8개의 sub-frame으로 나누어 동일한 영상 데이터를 8회 refresh함으로써 픽셀 내 커패시터에 sampling된 영상 데이터가 유지 기간 동안 MOSFET 스위치를 통한 누설 전류로 인해 손실되는 정도를 감소시킨다. Emitter에서 투사되는 적외선 영상의 높은 유효온도를 위해 전류 구동형 RIIC를 설계하였으며, 외부의 DAC로부터 아날로그 전압 형태의 영상 데이터를 전송 받는다. 시제품 $64{\times}32$ RIIC array 칩은 매그나칩/SK하이닉스 $0.35{\mu}m$ 2-poly 4-metal CMOS 공정으로 제작되었으며, 출력 가능한 최대 데이터 전류는 $230.3{\mu}A$이다. 이를 $15k{\Omega}$의 저항 값을 갖는 시제품 emitter 소자에 인가할 시 mid-wavelength IR (MWIR) 대역을 기준으로 최대 $366.2^{\circ}C$의 유효온도를 갖는 적외선 영상의 투사가 가능하다.

• 대한기계학회논문집B
• /
• 제22권6호
• /
• pp.849-859
• /
• 1998

The heat generated in an induction motor is mostly dissipated through the frame. The study on the heat transfer characteristics of a newly manufactured finless TEFC(Totally Enclosed Fan Cooled) induction motor showed/that it had an unsuitable structure in view of the heat transfer. The angle of the cooling air flow was very large and the ribs disturbed the air flow and partially generated the wake region on the frame. In the wake region the temperature was very high. Thus the heat transfer coefficients were lower than those of the frame with fins. Also was investigated the heat transfer characteristics of the motor frame by installing various guide vanes in the fan-side end cap. An optimum heat transfer case was found and the average heat transfer coefficient of the frame was 70% higher and the average coil temperature measured by the resistance method was 9 deg. C lower than that of the frame which had no guide vanes.

• 한국수소및신에너지학회논문집
• /
• 제29권1호
• /
• pp.56-63
• /
• 2018

In this study, a $100cm^2$ cell frame for a molten carbonate fuel cell was designed using CFD analysis. Electrochemical reactions, gas flow, and the heat transfer in $100cm^2$ cell frame were modeled using COMSOL Multiphysics. Two design variables such as the height of the cell frame and the length of the gas input area were determined to obtain minimized temperature distribution and uniform gas distribution. With two design parameter such as height of the cell frame and the length of the gas flow channel, the temperature difference in the cell fame was decreased to $5^{\circ}C$ and the gas uniformity in the flow channel were achieved.

• 국제초고층학회논문집
• /
• 제7권4호
• /
• pp.343-362
• /
• 2018

A simplified spring connection modelling approach for steel flush endplate beam-to-column connections in fire has been developed to enable realistic behaviour of connections to be incorporated into full-scale frame analyses at elevated temperature. Due to its simplicity and reliability, the proposed approach permits full-scale high-temperature frame analysis to be conducted without high computational cost. The proposed simplified spring connection modelling approach has been used to investigate the influence of connection ductility (both axial and rotational) on frame behaviour in fire. 2D steel and 3D composite frames with a range of beam spans were modelled to aid the understanding of the differences in frame response in fire where the beam-to-column connections have different axial and rotational ductility assumptions. The modelling results highlight that adopting the conventional rigid or pinned connection assumptions does not permit the axial forces acting on the connections to be accurately predicted, since the axial ductility of the connection is completely neglected when the rotational ductility is either fully restrained or free. By accounting for realistic axial and rotational ductilities of beam-to-column connections, the frame response in fire can be predicted more accurately, which is advantageous in performance-based structural fire engineering design.