• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05b
• /
• pp.197-200
• /
• 2006

The ingress of chloride ions plays a crucial role for service life design of reinforced concrete structures. In view of durability design of concrete structures under marine environment, one of the most essential parameters is the surface chloride content of concrete. However, on the basis of the results of in-situ investigation, this value has been determining in the numerous studies on the durability design of concrete structures. Hence, it is necessary to confirm the range of the surface chloride content in order to establish a unified durability design system of concrete. This study suggests a rational and practical way to calculate the maximum surface chloride content of submerged concrete under marine environment. This approach starts with the calculation of the amount of chloride ingredients in normal sea water. The capillary pore structure is modeled by numerical simulation model HYMOSTRUC and it is assumed to be completely saturated by the salt ingredients of sea water. In order to validate this approach, the total chloride content of the mortar and concrete slim disc specimen was measured after the immersion into the artificial sea water solution. Additionally, the theoretical, the experimental and in-situ investigation results of other researchers are compiled and analyzed. Based on this approach, it will follow to calculate the maximum surface chloride content of concrete at tidal zone, where the environment can be considered as a condition of dry-wetting cycles.

• Korean Journal of Human Ecology
• /
• v.7 no.1
• /
• pp.69-80
• /
• 2004

The purpose of this study is to suggest methods for the community design through users' behavior study in apartment housing. This study was approached by using both theoretical investigation and empirical research. The theoretical investigation actualized the concept of community design in apartment housing through a literature survey. The empirical survey focused on seeking out a user-oriented design criteria based on the analysis of residents' usage behavior and mental map. The results of this study are as follow: First. regarding the analysis of the residents' attitude toward the share community space(SCS), it was found that the SCS made a sense as community facilities in apartment housing. Second, regarding the SCS through the metal map, it was shown that the sketch map analysis was a useful research method for the community design by actualizing the residents' behavior characteristics. Third. as to the results of analyzing the metal map, it was found that the considered characteristics in recognition of the SCS were related to the liking with the main paths, cross nodes of the moving line, the location of center. and the complexity. In conclusion, the SCS is the main of community design in apartment housing and the above characteristics in recognition are useful as the guidelines in the SCS planning.

• Korean Journal of Social Welfare
• /
• v.43
• /
• pp.193-221
• /
• 2000

The conventional framework of welfare politics, based on class concepts, tends to fail in explaining the recent social changes. Theoretical response from the social science diverges into two blocs. One is the postmodernist approach that denies possibility of structural cleavage; the other is the alternative trial that seeks to find various kinds of cleavages. The former approach is to be rejected because there is few empirical supports for it. The latter is too sparse to be applied to the studies of welfare politics that requires a comprehensive analysis. This study starts from critical investigation of such approaches, aiming at providing a theoretical framework that combines merits of existing studies on welfare politics. The theoretical framework of three statuses of welfare rights and duties, which is to be presented as an alternative to the conventional class counterpart, does not only underscore the expansion of welfare rights but also the burden of welfare duties. Hence, it can comprehensively subsume complex existence of interest cleavages of welfare politics. To make a long story short, individual interest, related to the welfare state, will effect individual attitudes toward the welfare state and their ways of political support.

• ETRI Journal
• /
• v.18 no.4
• /
• pp.315-338
• /
• 1997

We extend our previous theoretical analysis of electronic and optical properties of p-type quantum well structures based on the two heavy- and light-hole system to include all the three valence bands. These theories are then used to clarify the origin of the normal incidence absorption and photo current at photon wavelengths of 2 - 3 ${\mu}m$, which was observed in addition to the absorption around 8 ${\mu}m$ by a recent experimental investigation with heavily doped p-type GaAs/AlGaAs multi-quantum well (MQW) structures. In the theoretical analysis, the Hartree and exchange-correlation many-body interactions are taken into account within one-particle local density approximation, and it is shown that normal incidence absorption occurs in two wavelength regions over the transition energy range higher than barrier height for p-type GaAs/AlGaAs superlattices with well doping of $2{\times}10^{19}\;cm^{-3}$; one region has broad absorption peaks with coefficients of about 5000 $cm^{-1}$ around 8 ${\mu}m$, and the other has two rather sharp peaks at 2.7 ${\mu}m$ and 3.4 ${\mu}m$ with 1800 $cm^{-1}$ and 1300 $cm^{-1}$, respectively. The result indicates that the theory explains the experimental observation well, as the theoretical and experimental results are in close agreement in general absorption features.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.8 no.1
• /
• pp.53-66
• /
• 1971

The effect of reinforced circular hole in a flat plate under general biaxial loading conditions is considered. The reinforcement is achieved by attaching a circular ring of uniform rectangular cross section along the boundary of the hole. This investigation includes a theoretical solution and an experimental conformation. In the theoretical analysis, Gurney's method is used to obtain a solution for the stress distribution and the solution is expressed in a general form, so that it can be applicable to the case of general biaxial loading and general values of Poisson's ratios. In the experimental work a systematic series of photoelastic models, as shown in Fig.5 and Table 1, were analyzed on polariscope. The experimental results were in good agreement with the theoretical ones, as shown in Fig.8 and 9. The conclusions derived are as follows: 1) The theoretical results, given in Eq. $(1){\sim}(5)$, are sufficient in accuracy for the engineering design purpose. 2) The stress concentration factor decreases as the ratio n increases, but not significant beyond n=3. 3) The stress concentration factor increase as the ratio m increases, but not significant below m=0.7.

• Wind and Structures
• /
• v.17 no.5
• /
• pp.479-494
• /
• 2013

The vehicle-induced aerodynamic loads bring vibrations to some of the highway sound barriers, for they are designed in consideration of natural wind loads only. As references to the previous field experiment, the vehicle-induced aerodynamic loads is investigated by numerical and theoretical methodologies. The numerical results are compared to the experimental one and proved to be available. By analyzing the flow field achieved in the numerical simulation, the potential flow is proved to be the main source of both head and wake impact, so the theoretical model is also validated. The results from the two methodologies show that the shorter vehicle length would produce larger negative pressure peak as the head impact and wake impact overlapping with each other, and together with the fast speed, it would lead to a wake without vortex shedding, which makes the potential hypothesis more accurate. It also proves the expectation in vehicle-induced aerodynamic loads on Highway Sound Barriers Part1: Field Experiment, that max/min pressure is proportional to the square of vehicle speed and inverse square of separation distance.

• Journal of Hydrogen and New Energy
• /
• v.34 no.4
• /
• pp.350-357
• /
• 2023

In this study, the experimental investigation and theoretical analysis were conducted to verify the cooling capacity of the cryocooler used for pre-cooling of hydrogen gas. The effect of the flow rate on a copper pipe attached to the bottom of the cryocooler, which has a coil shape in a hydrogen line, was investigated. Temperature sensors were strategically placed at various positions on the cryocooler to analyze the temperature variations with respect to the flow rate. In this study, the thermal properties of hydrogen for the pressure and temperature were utilized using REFPROP to analyze the cooling capacity of the cryocooler. Based on the experimental results derived from this study, the cooling capacity of the cryocooler for pre-cooling hydrogen gas was considered by calculating the cooling temperature according to the flow rate through theoretical analysis.

• Fire Science and Engineering
• /
• v.13 no.3
• /
• pp.3-17
• /
• 1999

Smoldering is a non-flaming combustion mode, characterized by thermal degradation and c charring of the virgin material, evolution of smoke and emission of visible glow. A big fire may @ occur even in a confined environment having a limited amount of oxygen, due to smoldering c combustion through a porous solid material. This paper presents a theoretical analysis on the effect of smoldering combustion on fire occurrence based on a report about fire investigation of a real f fire accident. It is assumed that the propagation of the smolder wave is one-dimensional, d downward, opposing an upward forced flow and steady in a frame of reference moving with the s smolder wave. Smoldering combustion is modeled by a one-step reaction mechanism, without c considering pyrolysis. It is found that dominant parameters controlling smoldering combustion i include mass flux of oxidizer entering the reaction zone and void fraction of solid fuel. It is also found that the mechanism of transition to flaming is critically influenced by these two parameters.

• Korean Security Journal
• /
• no.42
• /
• pp.449-468
• /
• 2015

It is important to identify and discuss what the most vial contributions of criminological theories. In the field of criminology, most significant contributions or advancement have been made on the various issues such as age, the integration of structural and procedural level theories, other theoretical integration debates. However, it is hard to find ant systematic study exploring such a contribution in criminological theories. This study, therefore, has a purpose to discuss three most significant contributions to our theoretical understanding of criminal behavior made since 1985. To accomplish the study purpose, this study choose the followed three theoretical contributions; the emergence of life course theory, the revision of social disorganization theory, and the introduction of social structure and social Learning (SSSL) model. The three theoretical works will be introduced and discussed regarding other theoretical integration trends in the body of this study. The conclusion, contribution of this current study has been discussed in the last conclusion and discussion section.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.8
• /
• pp.1591-1598
• /
• 2002

This paper reports on the effects of crankshaft offset on the engine friction. The effects of crank offset are investigated through the theoretical analysis. In this study, the mathematical models are presented fer evaluationg the friction level of each engine parts. Crank offset influences on the side force acted on the piston pin and sliding speed of piston. Crank offset is very effective to reduce the piston skirt friction. With application of crank offset, total engine friction decreases at low engine speed, but that increase as engine speed increases.