• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.04b
• /
• pp.547-552
• /
• 1998

Lateral pressure by circular reinforcement greatly enhances the maximum strength and ductility of spiral columns. The lateral confinement effects will be improves ductility of high-strength concrete. The major purpose of this paper is to study on the improvements of maximum strength and strain at that point of spiral concrete columns subject to axial loads. For this purpose, this study collected the other analytical results and the experimental data that has been performed by a lot of worldwide researchers and also analyzed it statistically. As the result, the theoretical equation for predict maximum strength and strain at that point was proposed. It is based on calculation of lateral confinement pressure generated by circular reinforcement, and the resulting improvements in strength and ductility of confined concrete.

• Journal of Chest Surgery
• /
• v.32 no.2
• /
• pp.198-200
• /
• 1999

Esophageal perforation due to the air pressure generated by forcefully evaporating gas is seldomly reported. If the diagnosis is confined to the injury of the oral cavity and the pharynx, missing the injury of the esophagus, the result may be fatal. Cases like this must be managed by early diagnosis and appropriate surgical intervention. The most important thing for early diagnosis is suspicion of esophageal injury from history and physical examination. We report two cases of esophageal pneumatic perforation caused by an explosive gas from the carbonated beverage bottle.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.11a
• /
• pp.351-354
• /
• 2003

Triaxial behavior of concrete cylinders wrapped with FRP material has been investigated for the increase of concrete strength by lateral confinement. Using the model by Richart et al., a modified empirical equation was proposed to estimate the strength of concrete cylinders with FRP confinement based on the linear relationship between the concrete strength and lateral confining pressure. From the experimental stress-strain result of the cylinder specimens having similar confining pressure, less ductility was observed for higher strength concrete. But the compressive strength of the specimen was linearly increased by lateral confinement. The confinement effectiveness coefficient for the strength enhancement of the cylinders by FRP wrap was obtained as 2.27 from the regression analysis.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.10 no.5
• /
• pp.125-130
• /
• 2011

The characteristics of unsteady combustion were experimentally investigated using confined premixed flames stabilized by a rearward-facing step. The unsteady combustion used in this experiment plays an important role in controlling self-excited combustion oscillations and it has usually desirable performance such as high load combustion and low pollutant emission. It is known that combustion oscillation is occurred if Rayleigh's criterion is satisfied. The pressure fluctuation and OH-emission fluctuation were measured using pressure transducer and OH optical fiber respectively and then cross-corelation and phase difference were calculated to apply Rayleigh's criterion.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.10b
• /
• pp.609-614
• /
• 1998

Lateral pressure by tied reinforcement greatly enhances the maximum strength and ductility of columns under concentric loading. The lateral confinement effects will be improves ductility of high-strength concrete. The major purpose of this paper is to study on the improvements of maximum strength and strain at the point of tied high-strength concrete columns subject to axial loads. For this purpose, this study collected the other analytical results and the experimental data that has been performed by a lot of worldwide researchers and also analyzed it statistically. As the result, the theoretical equation for predict maximum strength and strain at the point was proposed. It is based on calculation of lateral confinement pressure generate from tensile that develop in transverse reinforcement.

• Journal of the Korean Society of Combustion
• /
• v.18 no.2
• /
• pp.23-31
• /
• 2013

Compact steam boiler is a useful heat exchanger in a space-intensive system. There are some constraints in terms of sizing and designing the space confined in the system which is usually used in vessels. In this study, design considerations for heavy duty heat exchangers of compact steam boilers are presented and evaluated. Especially, evaporator tubes of marine boiler which are exposed to a high temperature environment are considered. Also, extended surface designs with a high temperature are examined. In order to determine the criteria with considerations of both heat transfer rate and pressure drop in the heat exchanger, they are evaluated with major variables, such as the tube diameter, the number of tubes, and the tube length. Finally, the design parameters are estimated as the bare tubes are installed instead of the finned tubes.

• 한국방재학회:학술대회논문집
• /
• 2008.02a
• /
• pp.447-450
• /
• 2008

A storm surge is gradually increased in the Korean peninsula. Furthermore, this phenomenon is confined not only the Korean peninsula but also the whole world. A storm surge induced by storm, typhoon, or cyclone is a phenomenon that the water surface elevation is raising by the barometric pressure difference and this water level rising threatens the coastal facilities, settlement, or lives. Most of coastal region in our country are unsafe from this disaster. Even though we are not able to prevent the generation of this phenomenon, we can reduce the damages by investigating the kind of storm surge disaster. Once we finish this investigation, we can reduce the damages by offering the information for risk prior to an invasion of storm surge. This study, we analyzed the previously occurred storm surge damages, and this data can be utilized as a guide for those who live near the coastal region providing the information about the predicting scale of the storm surge

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.12B
• /
• pp.1083-1096
• /
• 2008

This paper proposes an energy-aware path management scheme, so-called the TBP(Threshold based Back-Pressure) algorithm, which is designed for lifetime extension of the energy-constrained wireless sensor networks. With the goal of fair energy consumptions, we extensively utilize the available paths between the source and the sink nodes. The traffic distribution feature of the TBP algorithm operates in two scales; the local and the whole routing area. The threshold and the back-pressure signal are introduced for implementing those operations. It is noticeable that the TBP algorithm maintains the scalability by defining both the threshold and the back-pressure signal to have their meanings locally confined to one hop only. Throughout several experiments, we observe that the TBP algorithm enhances the network-wide energy distribution. which implies the extension of the network lifetime. Additionally, both the delay and the throughput outcomes show remarkable improvements. This shows that the energy-aware path control scheme holds the effects of the congestion control.

• Proceedings of the KSME Conference
• /
• 2001.06e
• /
• pp.57-62
• /
• 2001

Korea Atomic Energy Research Institute (KAERI) launched an intermediate scale steam explosion experiment named Test for Real cOrium Interaction with water (TROI) using reactor material to investigate whether the corium would lead to energetic steam explosion when interacted with cold water at low pressure. The melt-water interaction is confined in a pressure vessel with the multi-dimensional fuel and water pool geometry. The cold crucible technology, where the mixture of powder in a water-cooled cage is heated by high frequency induction, is employed. In this paper, results of the first series of tests ($TROI-1{\sim}5$) were discussed. The ZrO2 jets with 5kg mass and 5cm diameter were poured into the 67cm deep water pool at $30{\sim}95^{\circ}C$. Either spontaneous steam explosions or quenching was observed. The morphology of debris and pressure wave profiles clearly indicates the each case.

• Journal of the Optical Society of Korea
• /
• v.16 no.1
• /
• pp.22-28
• /
• 2012

We report a focal-length tunable liquid lens based on thermopneumatically driven fluidic pressure. The fluidic pressure is generated by deformation of an elastomeric diaphragm induced by thermopneumaticity from a laterally integrated microheater sealed within an air chamber. The pressure is transmitted by a confined liquid to a lens diaphragm through an internal fluid channel. The liquid filling under the lens diaphragm functions as a liquid lens for dynamic focusing with properties depending on the curvature of the deformed diaphragm. The diaphragm area of the air chamber is designed five times larger than that of the lens cavity to yield high focal-length tunability by amplified deflection of the lens diaphragm. With our method, we achieved excellent focal-length tunability from infinity (without an input current) to 4 mm (with an input current of 12 mA) with a lens aperture diameter of 2 mm.