• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.679-680
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• 2009

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.122-128
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• 2022

Minimization of human casualties in disaster situations is of paramount importance. In particular, if a marine disaster occurs, it can be directly connected to human casualties, so prompt action is needed. In the event of a marine disaster, the route and location of movement should be identified and life tubes should be used to float on the water. This paper designs and proposes an emergency IoT notification system that can quickly rescue drowning people. The maritime emergency IoT notification system consists of four main types. First, an emergency IoT device that detects the expansion of the life tube and delivers location and situation information to the emergency IoT notification server. Second, an emergency IoT web server that manages emergency information and provides notification. Third, a database server that stores and manages emergency IoT notification information. And finally, an emergency notification app that can receive and respond to emergency notification information. The emergency IoT device consists of a TPMS(Tube Pressure Monitoring System) device that checks the pressure value of the TPMS in real time and sends it to the IoT device, and an IoT device that sends the rescuer's voice information and emergency information to the emergency IoT server. Emergency information is delivered using the MQTT(Message Queuing Telemetry Transport) protocol, and voice information is delivered to the IoT server as HTTP FormData.

• Transactions of Materials Processing
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• v.15 no.2 s.83
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• pp.138-142
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• 2006

A tube hydroformability testing system was designed and manufactured to observe the forming steps and to provide arbitrary combination of internal pressure and axial fred. The forming limit diagram of an aluminum tube was obtained from the free bulge test and the T-shape forming test using this system, giving the criteria for predicting failure in the hydroforming process. The hydroformability of aluminum tube according to different conditions of a prebending process was discussed, based on the finite element analysis and the forming limit test. The effects of 2D and 3D pretending on the tube hydroforming process of an automotive trailing arm were evaluated and compared with each other.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.243-246
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• 2005

A tube hydroformability testing system was designed and manufactured to observe the forming steps and to provide arbitrary combination of internal pressure and axial feed. The forming limit diagram of an aluminum tube was obtained from the free bulge test and the T-shape forming test using this system, giving the criteria for predicting failure in the hydroforming process. The hydroformability of aluminum tube according to different conditions of a prebending process was discussed, based on the finite element analysis and the forming limit test. The effects of 2D and 3D prebending on the tube hydroforming process of an automotive failing arm were evaluated and compared with each other.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.5
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• pp.1218-1226
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• 1994

The shock tube is a useful device for investigating shock phenomena, spray combustion, unsteady gas dynamics, etc. Therefore, it is necessary to analyze exactly the flow phenomena in shock tube. In this study, the mechanics of its reflected shock zone has been investigated by using of the one-dimensional gas dynamic theory in order to estimate the transition from initial reflection of shock wave region. Calulation for four kinds of reflected shock tube temperature (i.e. (a) 1388 K (b) 1276 K (c) 1168 K (d) 1073 K) corresponding to the experimental conditions have been carried out sumarized as follows. (1) The qualitative tendency is almost the same as in that conditions in region of reflected wave region. (2) High temperature period (reflected shock wave temperature) $T_{5}$, exists 0-2.65 ms. (3) Transition period from temperature of reflection shock wave is far longer than the calculated one. This principally attributed to the fact that the contact surface is accelerated, also, due to the release of energy by viscoity effect. This apparatus can advance the ignition process of a spray in a ideal condition that involved neither atomization nor turbulent mixing process, where, using a shock tube, a column of droplets freely from atomizer was ignited behind a reflected shock.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.1
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• pp.31-37
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• 2006

The present study has been experimentally investigated the effect of geometric and operating parameters on the two-phase flow distribution of refrigerants in a horizontal T-junction. The operating parameters were the kind of refrigerants (R-22, R- l34a, and R-410A), saturated temperature, and the inlet mass flux and quality. The geometric parameters were the tube diameter and the tube diameter ratio. The measured data of refrigerants were compared with the values predicted using the models developed by several researchers for air/water or steani/water two-phase flow. Among the operating parameters, the inlet Quality was the most sensitive to the mass flow rate ratio. Between the geometric parameters, the tube diameter ratio was more sensitive than tube diameter.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.23-26
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• 2004

The deformation behaviors of fully annealed or T6-treated 6061 and 7075 aluminum tubes are investigated at elevated temperature using uniaxial tensile test. Fully annealed 6061 and 7075 tube, and T6-treated 7075 tube do not show sharp local necking with an elongation of $50\%$ at tensile temperature of $300^{\circ}C$, accordingly, it is expected that warm hydroforming process can be applied. The increase of tensile temperature does not significantly affect the total elongation of T6-treated 6061 tube.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1983.05a
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• pp.10.2-10
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• 1983

Tracheal stenosis induced from the various causes has still remained as a serious problem in the otolaryngologic field. There has been used the numerous methods in the treatment of the tracheal stenosis and the each case has required the therapeutic modality. Now, we report two cases of tracheal stenosis ; one case had been used the silicone T - tube in the tracheal stenosis after tracheostomy in 6 year - old child and the other one had been used the silicone tube stent with oral mucosa graft in the treatment of the tracheal narrowing due to inflammatory mass in 19 year - old male patient.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.3
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• pp.254-261
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• 2006

The effect of enhanced geometry (pore diameter, gap width) is investigated on the pool boiling of R-123/oil mixture for the enhanced tubes having pores with connecting gaps. Tubes with different pore diameters (and corresponding gap widths) are specially made. Significant heat transfer degradation by oil is observed for the present enhanced tubes. At 5% oil concentration, the degradation is 26 to 49% for $T_{sat}=4.4^{\circ}C$. The degradation increases 50 to 67% for $T_{sat}=26.7^{\circ}C$. The heat transfer degradation is significant even with small amount of oil (20 to 38% degradation at 1% oil concentration for $T_{sat}=4.4^{\circ}C$), probably due to the accumulation of oil in sub-tunnels. The pore size (or gap width) has a significant effect on the heat transfer degradation. The maximum degradation is observed for $d_p$ = 0.20 mm tube at $T_{sat}=4.4^{\circ}C$, and for $d_p$=0.23 mm tube at $T_{sat}=26.7^{\circ}C$. The minimum degradation is observed for $d_p$=0.27 mm tube for both saturation temperatures. It appears that the oil removal is facilitated for the larger pore diameter (along with larger gap) tube. The highest heat transfer coefficient with oil is obtained for $d_p$ =0.23 mm tube, which yielded the highest heat transfer coefficient for pure R-123. The heat transfer degradation increases as the heat flux decreases.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.12
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• pp.1484-1493
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• 2004

In this study, it induced to a conclusion below by experiment consideration to regarding an effective supercooling ends method of the flow cooling water in a tube of continuous ice making method and the static cooling water in a tube of continuous ice making method which used magneticfluid in a dynamic type ice storage system. Continuous ice making in a tube of the flow cooling water was shortened about 12 minutes until supercooling ends that case which gave vertical eccentricity rotation magnetic field 120rpm than did not provide magnetic field by experimental result that was tested to supercooling ends effect from shape control of magneticfluid. Continuous ice making method in a tube of the static cooling water compared with and reviewed the case that was not provided with the magnetic field and exposed cooling surface instantaneously by magnetic field. It confirmed that supercooling degree $\Delta$ $T_{c}$, $\Delta$ $T_{s}$, and $\Delta$ $T_{w}$ became lower because of heat transfering increasing by the occurrence of natural convection between after cooling starting progress time 1∼3 minutes if it did not give a magnetic field, and peformed the supercooling ends when natural convection occurred confirmed that refrigerating capacity was better. That relation $\Delta$ $T_{c}$, and $t_{e}$/($\Delta$ $T_{c}$-$\Delta$ $T_{s}$) after convection occurred, was not depended on $T_{b}$ and initial temperature if the depth of water and thickness of magneticfluid were regular and it was possible to verify conjecture of tp from $\Delta$ $T_{s}$ and $\Delta$ $T_{c}$.lar and it was possible to verify conjecture of tp from $\Delta$ $T_{s}$ and $\Delta$ $T_{c}$.c}$.>.