• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1178-1185
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• 2010

Recently, high speed of container freight cars is causing fatigue damage of wheel. Sudden failure accidents cause a lot of physical and human damages. Therefore, damage analysis for wheel prevents failure accident of container freight car. Wheel receives mechanical and thermal loads at the same time while rolling stocks are run. The mechanical loads applied to wheel are classified by the horizontal load from contact of wheel and rail in curve line section and by the vertical force from rolling stocks weight. Also, braking and deceleration of rolling stocks cause repeated thermal load by wheel tread braking. Specially, braking of rolling stocks is frictional braking method that brake shoe is contacted in wheel tread by high breaking pressure. Frictional heat energy occurs on the contact surface between wheel tread and brake shoe. This braking converts kinetic energy of rolling stocks into heat energy by friction. This raises temperature rapidly and generates thermal loads in wheel and brake shoe. There mechanical and thermal loads generate crack and residual stress in wheel. Wetenkamp estimated temperature distribution of brake shoe experimentally. Donzella proposed fatigue life using thermal stress and residual stress. However, the load applied to wheel in aforementioned most researches considered thermal load and mechanical vertical load. Exact horizontal load is not considered as the load applied to wheel. Therefore, above-mentioned loading methods could not be applied to estimate actual stress applied to wheel. Therefore, this study proposed safety estimation on wheel of freight car using heat-structural coupled analysis on the basis of loading condition and stress intensity factor.

• Korean Chemical Engineering Research
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• v.58 no.3
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• pp.458-465
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• 2020

Isotherms, kinetics and thermodynamic properties for adsorption of acid fuchsin (AF) dye by activated carbon were carried out using variables such as dose of adsorbent, pH, initial concentration and contact time and temperature. The effect of pH on adsorption of AF showed a bathtub with high adsorption percentage in acidic (pH 8). Isothermal adsorption data were fitted to the Freundlich, Langmuir, and Dubinin-Radushkevich isotherm models. Freundlich isothem model showed the highest agreement and confirmed that the adsorption mechanism was multilayer adsorption. It was found that adsorption capacity increased with increasing temperature. Freundlich's separation factor showed that this adsorption process was an favorable treatment process. Estimated adsorption energy by Dubinin-Radushkevich isotherm model indicated that the adsorption of AF by activated carbon is a physical adsorption. Adsorption kinetics was found to follow the pseudo-second-order kinetic model. Surface diffusion at adsorption site was evaluated as a rate controlling step by the intraparticle diffusion model. Thermodynamic parameters such as activation energy, Gibbs free energy, enthalpy entropy and isosteric heat of adsorption were investigated. The activation energy and enthalpy change of the adsorption process were 21.19 kJ / mol and 23.05 kJ / mol, respectively. Gibbs free energy was found that the adsorption reaction became more spontaneously with increasing temperature. Positive entropy was indicated that this process was irreversible. The isosteric heat of adsorption was indicated physical adsorption in nature.

• Clean Technology
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• v.26 no.1
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• pp.30-38
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• 2020

The kinetic and thermodynamic parameters of Acid Red 66, adsorbed by granular activated carbon, were investigated on areas of initial concentration, contact time, and temperature. The adsorption equilibrium data were applied to Langmuir, Freundlich, Temkin, Redlich-Peterson, and Temkin isotherms. The agreement was found to be the highest in the Freundlich model. From the determined Freundlich separation factor (1/n = 0.125 ~ 0.232), the adsorption of Acid Red 66 by granular activated carbon could be employed as an effective treatment method. Temkin's constant related to adsorption heat (B_T = 2.147 ~ 2.562 J mol^-1) showed that this process was physical adsorption. From kinetic experiments, the adsorption process followed the pseudo-second order model with good agreement. The results of the intraparticle diffusion equation showed that the inclination of the second straight line representing the intraparticle diffusion was smaller than that of the first straight line representing the boundary layer diffusion. Therefore, it was confirmed that intraparticle diffusion was the rate-controlling step. From thermodynamic experiments, the activation energy was determined as 35.23 kJ mol^-1, indicating that the adsorption of Acid Red 66 was physical adsorption. The negative Gibbs free energy change (ΔG = -0.548 ~ -7.802 kJ mol^-1) and the positive enthalpy change (ΔH = +109.112 kJ mol^-1) indicated the spontaneous and endothermic nature of the adsorption process, respectively. The isosteric heat of adsorption increased with the increase of surface loading, indicating lateral interactions between the adsorbed dye molecules.

• Clinical and Experimental Pediatrics
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• v.53 no.1
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• pp.67-71
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• 2010

Purpose : Recently, we have noticed an increase in the number of patients with mumps in Incheon, Korea. The aim of this study is to estimate the regional trend in mumps incidence and to evaluate the factors related to the recent increase. Methods : We reviewed the medical records of 66 patients with mumps who had been admitted to Incheon St. Mary's Hospital from July 1999 to June 2009. We compared the differences in records between "outbreak, 2009" and "nonoutbreak, 2000-2008." Results : Of the 66 patients, 35 (53%) were admitted in 2009, and 31 (47%) were admitted between 2000 and 2008. Most of the patients admitted during the outbreak were over 15 years of age (80.0%), were born before 1993 (77.1%), and had received a single dose of mumps vaccine (62.9%). There were no significant differences in contact history, present address, clinical manifestations, and complications, except for orchitis, between the two groups. Conclusion : There was a sharp increase in the number of inpatients with mumps who were born before 1993 and who were over 15 years of age. We recommend that a booster vaccination be considered for adolescents and young adults born before 1993 who are susceptible to mumps infection due to their reduced opportunities for receiving two doses of mumps vaccine.

• Parasites, Hosts and Diseases
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• v.34 no.2
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• pp.113-120
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• 1996

An epidemiological survey was performed to know the status of Cwptespori,mum sp. infection among the people in Seoul and Chollanam-do in 1992. One village of Chollanam-do (Hwasun-gun) which showed the highest oocyst positive rate was re-surveyed in 1995 for human infection and for cattle also. The subjected areas consisted of 8 urban villages (: dongs) of Seoul and 4 urban (: dongs) and 7 rural (: myonsl villages of Chollanam-do. A total of 3,146 fecal samples was collected randomly, and smears were made from formalin-ether sediments. They were examined for Cwptosporinium oocysts by modified acid fast staining. The overall oocyst positive rate was 79% (248/3,146), but the rate was remarkably different between Seoul and Chollanam-do, 0.5% (4/853) and 10.6% (244/2,293), respectively The average size of oocysts was 4.8 ± 0.5 by 4.2 ± 0.5 ㎛, compatible with C. pcnlum. In Chollanam-do, rural villages showed significantly higher rate (14.0%) than urban villages (3.7%). Especially the people in Iyang-myon, Hwasun- gun, a typical rural village, revealed a very high rate of 40.0% (74/185). Adults aged 51-70 years revealed the highest positive rate among all age groups. At the re-survey of the same village of Hwasun-fun in 1995, 44 (35.2%) of 125 villagers and 14 (93.3%) of IS cattle examined were positive for C. pnnpum oocysts. The results suggest that C. pnnpum is highly prevalent in rural areas of Chollanam-do, and an important source or mode of infection seems to be contaminated water or contact with the feces of infected cattle.

• Journal of Preventive Medicine and Public Health
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• v.19 no.1 s.19
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• pp.45-55
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• 1986

It is well known that Korea is one of the endemic area for type B viral hepatitis. A screening test for HBsAg by RPHA method was performed to evaluate the prevalence of HBsAg among urban, rural and coastal area population during the period between Jan. 1985 and Aug. 1985. The results obtained are as follows; 1) The HBsAg was detected in 242 among 2,849 with positive rate of 8.49%. The positive rate by sex showed higher rate in males(9.07%) than females(6.79%) for HBsAg. But these differences by sen were not statistically significant. 2) By living area, the positivity of HBsAg was 8.67% in urban, 7.43% in rural and 8.37% in coastal area. But the differences were not statistically significant. 3) The positivity differences of HBsAg were significantly observed between male(9.26%) and female(6.44%) in urban area. But there was not in rural and coastal area. 4) The positivity was the highest in 4th decade in urban area. But 6th decade in rural and 4th and 5th decade in coastal area. Generally the positivity of HBsAg was more prevalent in young age and decreasing by the age increasing in the male. But in the female it was most common in 6th decade. 5) Elevated SGOT(>40 Unit) was significantly higher in HBsAg positive group(13.6%) than in HBsAg negative group(3.4%).

• Journal of KIISE:Software and Applications
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• v.32 no.3
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• pp.181-191
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• 2005

This article describes a simplified mathematical model and the relevant numerical algorithm to simulate the draped cloth on virtual human body. The proposed algorithm incorporates an elliptical, or non-consecutive, method to simulate the cloth wrinkles on moving bodies without resorting to the result of the past time-steps of drape simulation. A global-local analysis technique was employed to decompose the drape of cloths into the global deformation and the local wrinkles that will be superposed linearly The global deformation is determined directly by the rotation and the translation of body parts to generate a wrinkle-free yet globally deformed shape of cloth. The local wrinkles are calculated by solving simple elliptical equations based on the orthogonality between conjugate harmonic functions representing the wrinkle amplitude and the direction of wrinkles. The proposed method requires no interpolative time frames even for discontinuous body postures. Standing away from the incremental approach of time integration in conventional methods, the proposed method yields a remarkable reduction of CPU time and an enhanced stability. Also, the transient motion of cloth could be achieved by interpolating between the deformations corresponding to each static posture.

• Parasites, Hosts and Diseases
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• v.26 no.4
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• pp.255-262
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• 1988

An epidemiological study on brugian filariasis was carried out in endemic areas including Cheju Island in Korea, with a brief review of literatures. The results showed that the incidence among residents has remarkably decreased in Cheju Island, which was the main endemic area. Reviewing available informations on the prevalence of filariasis reported in recent years and also judging from the present socio·economic conditions which enable people to practice personal protection against mosquitos, it can be said with confidence that alariasis has almost disappeared from Cheju Island and inland areas. The disease is considered to remain at a low level of endemicity in Hugsan Islands. Certainly mass diethylcarbamasine (DEC) treatment carried out in Cheju Island in the 1960s and 1970s and remarkable economic growth followed by improved living standard and altered life-style of inhabitants could all have combined effects on the disappearance of this mosquito-borne disease in this island. If the present trends go on, the possibility of resurgence of filariasis in Cheju Island is hardly postulated.

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.450-455
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• 2012

The paper includes the utlization of an activated carbon as a potential adsorbent to remove a hazardous fluorescein dye from an aqueous solution. Batch adsorption experiments were carried out for the removal of fluorescein dyes using a granular activated carbon as an adsorbent. The effects of various parameters such as pH, amount of adsorbent, contact time, initial concentration and temperature of the adsoprtion system were investigated. The experimental results revealed that activated carbon exhibit high efficiencies to remove fluorescein dyes from the aqueous solution. The equilibrium process can be well described by Freundlich isotherm in the temperature range from 298 K to 318 K. From adsorption kinetic experiments, the adsorption process followed a pseudo second order kinetic model, and the adsorption rate constant ($k_2$) decreased with increasing the initial concentration of fluorescein. The free energy of adsorption ${\Delta}G^0$), enthalpy ${\Delta}H^0$), and entropy (${\Delta}S^0$) change were calculated to predict the nature adsorption. The estimated values for ${\Delta}G^0$ were -17.11~-20.50 kJ/mol over an activated carbon at 250 mg/L, indicated toward a spontaneous process. The positve value for ${\Delta}H^0$, 33.2 kJ/mol, indicates that the adsorption of fluorescein dyes on an activated carbon is an endothermic process.

• Clean Technology
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• v.26 no.2
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• pp.122-130
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• 2020

The isotherm, kinetic, and thermodynamic parameters of reactive blue 4 adsorbed by activated carbon were investigated for activated carbon dose, pH, initial concentration, contact time, and temperature data. The adsorption of the RB 4 dye by activated carbon showed a concave shape in which the percentage of adsorption increased in both directions starting from pH 7. The isothermal adsorption data were applied to Langmuir, Freundlich, and Temkin isotherms. Both Freundlich and Langmuir isothermal adsorption models fit well. From determined Freundlich separation factor (1/n = 0.125 ~ 0.232) and Langmuir separation factor (R_L = 1.53 ~ 1.59), adsorption of RB 4 by activated carbon could be employed as an effective treatment method. The constant related to the adsorption heat (B_T = 2.147 ~ 2.562 J mol^-1) of Temkin showed that this process was physical adsorption. From kinetic experiments, the adsorption process followed the pseudo second order model with good agreement. The results of the intraparticle diffusion model showed that the inclination of the first straight line representing the surface diffusion was smaller than that of the second straight line representing the intraparticle pore diffusion. Therefore, it was confirmed that intraparticle pore diffusion is the rate-controlling step. The negative Gibbs free energy change (ΔG = -3.262 ~ -7.581 kJ mol^-1) and the positive enthalpy change (ΔH = 61.08 kJ mol^-1) indicated the spontaneous and endothermic nature of the adsorption process, proving this process to be spontaneous and endothermic.