• Journal of The Korean Society of Clinical Toxicology
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• v.7 no.2
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• pp.143-149
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• 2009

Purpose: Suicide attempts are known to be influenced by mass media reports. The purpose of this study was to evaluate the effects of mass media reporting celebrity suicides on an increase of intentional carbon monoxide (CO) poisoning and suicide attempts. Methods: We retrospectively reviewed the medical records of the consecutive patients who presented with suicide attempts to the Emergency Department of Ajou University Hospital during a 24 month period. We obtained the demographic data, any past history of suicide attempt and the methods of suicide attempts from the medical records of the suicide attempters. Time series analysis was conducted for evaluating the influence of mass media reporting of celebrity suicide on the suicide rates. Results: We finally enrolled 770 patients during the study period. The total number of suicide attempts by CO poisoning was 18 and the average number of suicide attempts by CO was $0.33{\pm}0.73$ per week. All of the suicide attempts by CO poisoning occurred after a celebrity committed suicide using CO from burning charcoal. Conclusion: This study showed that celebrity suicide by CO poisoning resulted in the Werther effect, which made the rate of intended CO poisoning increase, and the study provided further evidence for the need to actively restrain mass media reporting of suicide to decrease the Werther effect.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.394-401
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• 1996

This paper persents the crack control of mass concrete in massive machine foundation. The dimension of the machine foundation is 52.6m$\times$14.4m$\times$8.5m. The one distinctive characteristic of mass concrete is thermal behavior. Since the cement-water reaction is exothermic by nature, the temperature rises inside the massive concrete structure. When the heat is not quickly dissipated, it can be quite high. Significant tensile stresses may develop from the volume change associated with the increase of decrease of temperature within the mass concrete structure. To avoid occurrence of harmful cracks due to hydration heat, special attention shall be given to the construction of mass cnocrete structures. The temperature control system of mass concrete is proposed in this paper. This system contains a discussion of materials and concrete mix proportioning, thermal analysis, curing method, temperature control, and measurement of hydration heat. As will be seen throughout the paper, the proposed temperature control system have a great effect on the temperature-related cracks on mass concrete structures.

• Journal of the Korean Society of Safety
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• v.22 no.4
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• pp.102-109
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• 2007

A bioterrorism attack is the deliberate release of viruses, bacteria, or other germs(agents) used to cause illness or death in people, animals, or plant. These agents are found in nature, but it is possible that they could be changed to increase their ability to cause disease, make them resistant to current medicines, or to increase their ability to be spread into the environment. Terrorists may use biological agents because these agents can be extremely difficult to detect and do not cause illness for several days. Some bioterrorism agents, like smallpox virus, can spread from person to person, like anthrax, can not. From these agents, we discussed the characteristics of biological agents and national safety regulation on the weapons of mass destruction including bioterrorism.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.586-590
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• 2006

This paper presents a new vibration control device by which the mass and damping of a structure is increased equivalently. The vibration control system, named toggle-rotational inertia-viscous damper, can be utilized effectively in applications of small structural drift. Numerical analysis shows that because the relative drift of a structure can be effectively amplified by the toggle system, the device has a great performance in the vibration control without the increase of the damper capacity and size. It is also observed that vibration control effects is caused by the increase of equivalent mass and damping due to the rotational inertia and damping of the device.

• Journal of the Korean Society of Combustion
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• v.16 no.3
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• pp.1-11
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• 2011

The main objective of this paper is to investigate characteristic of steam reformer at various geometries and operating conditions. In this paper, the steam reforming is studied by a numerical method and three dimensional simulations were used for effective analytical study. User - Defined Function (UDF) was used to simultaneously calculate reforming and combustion reaction. And the numerical model is validated with experimental results at the same operating conditions. In order to understand the relationship between operating conditions such as gas hourly space velocity(GHSV), mass flow rate of combustor inlet, various numerical investigations are carries out for various geometries. Numerical results show that cylindrical geometry is more effective than rectangular geometry for heat transfer to reactors and reforming efficiency. As mass flow rate of combustor inlet increase, reaction occurs more faster and temperature increase with each geometry. On the other hand, reaction and hydrogen conversion decrease as mass flow rate of reactor decreases.

• Korean Journal of Child Studies
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• v.8 no.1
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• pp.15-29
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• 1987

The purpose of the present research was to investigate (I) the acquisition of character constancy of self and others as a function of age; (2) the pattern of acquisition of character constancy, and (3) the relationships between character constancy and conservation of number and mass. The subjects of this study were 160 children, 20 boys and 20 girls at each grade level, kindergarter through grade 3. The Character Constancy Tasks devised bi Rotenberg (1982) and conservation task of number and mass were administered to each child. Chi square, Guttman Scale analysis and Pearson's Correlation were used for the statistical analysis of data. The findings showed that there was increase with age in character constancy of others and of sell in that there was increase with age in children's belief that the characteristics of another person are stable across time and consistent despite changes in a person's appearance. Character constancy of others and of self were acquired in the developmental stages of identity, stability, and consistency. Character constancy of others and self correlated with the conservation of number and mass.

• Clean Technology
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• v.9 no.1
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• pp.43-48
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• 2003

As a result of study on factor affecting absorption efficiency using the structured packing, Mellapak N. 250Y for the chemical absorption of $CO_2$ that cause global warming due to development of industry, it is shown that Mellapak N. 250Y has lower pressure drop and superior efficiency of mass transfer than 25mm Pall ring. Also, in the absorption process, it produces high efficiency in the increase of load and concentration of absorption liquid and produces low efficiency in the increase of temperature. In the effect of overall mass transfer coefficient for 15% MEA on the temperature variation of absorbent, when absorbent temperature for 15% MEA varied as 25, 50, $80^{\circ}C$, overall mass transfer coefficients were shown as 0.83, 1.00, $0.90kmol/m^3-h-kPa$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.10
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• pp.817-824
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• 2015

Experiments were carried out to investigate the flow and mass transfer characteristics of an orifice nozzle. Measurements of primary and suction flow rates, dissolved oxygen concentration, and electric power were obtained. Vertically injected mixed-jet images were captured by a direct visualization technique with a high speed camera unit. The mass ratio, volumetric mass transfer coefficient, and mass transfer performance were calculated using the measured data. As the primary flow pressure increases, the mass ratio decreases slightly, while the volumetric mass transfer coefficient and electric power increase. As the primary flow pressure increases and the mass ratio decreases, the mass transfer rate increases because of the fine bubbles and wider distribution of the bubbles.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.244-245
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• 2005

This paper presents the heat transfer and pressure drop characteristics during cooling process of carbon dioxide in a horizontal tube. The test section is a tube in tube type heat exchanger with refrigerant flowing in the inner tube and water flowing in the annulus. It was made of a stainless steel tube with the inner diameter of 7.75 [mm], the outer 2 diameter of 9.53 [mm] and length of 6000 [mm]. The refrigerant mass fluxes were $200{\sim}400$ [kg/$m^2s$] and the average pressure varied from 7.5 [MPa] to 10.0 [MPa]. The main results were summarized as follows The heat transfer coefficient of supercritical $CO_2$ increases in decrease of the gas cooler pressure. And the heat transfer coefficient increases with respect to the increase of the refrigerant mass flux. Among some correlations proposed in a transcritical region, Bringer-Smith's correlation has some analogy with experimental results. The pressure drop decreases in increase of the gas cooler pressure and increases with respect to increase the refrigerant mass flux.

• Advanced Composite Materials
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• v.16 no.4
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• pp.283-298
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• 2007

Environment-friendly composites reinforced with bagasse fiber (BF), a kind of natural fiber as the remains from squeezed sugarcane, were fabricated by injection molding and press molding. As appropriate matrices for injection molding and press molding, polypropylene (PP) and polycaprolactone-cornstarch (PCL-C) were selected, as a typical recyclable resin and biodegradable resin, respectively. The mechanical properties of BF/PP composites were investigated in view of fiber mass fraction and injection molding conditions. And the mechanical properties and the biodegradation of BF/PCL composites were also evaluated. In the case of injection molding, the flexural modulus increased with an increase in fiber mass fraction, and the mechanical properties decreased with an increase in cylinder temperature due to the thermal degradation of BF. The optimum conditions increasing the flexural properties and the impact strength were $90^{\circ}C$ mold temperature, 30 s injection interval, and in the range of 165 to $185^{\circ}C$ cylinder temperature. On the other hand, as to BF/PCL-C fully-green composites, both the flexural properties and the impact strength increased with an increase in fiber mass fraction. It is considered that the BF compressed during preparation could result in the enhancement in mechanical properties. The results of the biodegradability test showed the addition of BF caused the acceleration of weight loss, which increased further with increasing fiber content. This reveals that the addition and the quantities of BF could promote the biodegradation of fully-green composites.