• Journal of the Korea Institute of Building Construction
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• v.18 no.6
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• pp.507-515
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• 2018

The purpose of this research is to develop a slurry-type accelerator that contains various beneficial properties such as reduction of dust generation, lower alkalinity, early age strength development, etc., and uses such slurry type accelerator to produce high performance shotcrete that present excellent resistant against chloride ion penetration. In this work, shotcrete mixtures of 0.44 and 0.338 water-to-binder ratio (w/b) were produced at construction site using slurry-type accelerator. The mechanical properties and chloride ion penetration resistance of such shotcrete (including base concrete) were evaluated. According to the experimental results, the slurry-type accelerator was successfully used to produce both w/b 0.44 and 0.338 shotcretes. The 1 day and 28 day compressive strength of shotcrete were found to be closer to or higher than 10MPa and 40MPa, respectively. The w/b 0.338 shotcrete that used 40% replacement of blast furnace slag showed lower compressive strength than w/b 0.44 shotcrete without any mineral admixture at 1 day. However, the compressive strength with 40% blast furnace slag increased significantly at 28 day. Moreover, there was more than 50% increase in chloride ion penetration resistance with blast furnace slag, showing its strong potential for higher performance shotcrete application.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.61-68
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• 2019

As the pollution of water resources deteriorates due to industrialization and urbanization, it is difficult to supply clean water through a water treatment method using chlorine. Therefore, the introduction of advanced water treatment facilities using ozone is on the increase. However, epoxy which is used as waterproofing and anticorrosives and stainless steel used in conventional waterproofing and anti-corrosive methods have deteriorated because of the strong oxidizing power of ozone, causing problems such as leaking. Moreover, it even causes the durability degradation of a concrete. Therefore, in this study, metal spraying system was used as the means of constructing a metal panel with excellent ozone resistance and chemical resistance which is an easier method than an existing construction method. Ozone resistance was evaluated in accordance with the type of metal sprayed coatings to develop a finishing method which can prevent the concrete structure of water treatment facilities from deterioration. Furthermore, electrochemical stability in actual sewage treatment plant environment was evaluated. Experimental results showed that Ti has superior ozone resistance after spraying and the electrochemical stability in the sewage treatment plant environment showed that Ti has the highest polarization resistance of $403.83k{\cdot}{\Omega}{\cdot}cm^2$, which ensures high levels of durability.

• Clean Technology
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• v.27 no.2
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• pp.152-159
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• 2021

Volatile organic compounds (VOCs) occur in indoor and outdoor industrial and urban areas and cause environmental problems. Malodorous VOCs, along with aesthetic discomfort, can have a serious effect on the human body. Compared with the existing method of reducing malodorous VOCs, a wet scrubbing method using an electrolytic oxidant has the advantage of reducing pollutants and regenerating oxidants. This study investigated the optimal conditions for producing OCl^-, a chlorine-oxidant. Experiments were conducted by changing the type of anode and cathode electrode, the type of electrolyte, the concentration of electrolytes, and the current density. With Ti/IrO₂ as the anode electrode and Ti as the cathode electrode, OClproduction was highest and most stable. Although OCl^- production was similar with the use of KCl or NaCl, NaCl is preferable because it is cheap and easy to obtain. The effect of NaCl concentration and current density was examined, and the OCl^- production rate and concentration were highest at 0.75 M NaCl and 0.03 A cm^-2. However, considering the cost of electric power, OCl^- production under the conditions of 1.00 M NaCl and 0.01 A cm^-2 was most effective among the conditions examined. It is desirable to produce OCl^- by adjusting the current density in accordance with the concentration and characteristics of pollutants.

• Resources Recycling
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• v.29 no.6
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• pp.88-97
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• 2020

In this study, the selected waste plastic waste logistics used for cement sintering were classified into two types through the process of sorting and crushing, analyzing the characteristics of each, and analyzing the correlation of the strength after cement manufacturing. The experimental variables were classified into soft and hard waste plastic waste, and the correlations between calorific value, chlorine, and moisture were analyzed. In addition, some of each waste was selected and melted, and the basic characteristics were evaluated by analyzing the structure and calorific value. The results of the experiment showed that it was evaluated that it is suitable to obtain a heat source by separating soft waste plastic wastes and sintering them with materials having similar properties. As a result of examining the wastes by strength after cement manufacturing, it was analyzed that the use of hard plastics greatly contributes to the compressive strength on the 1st and 28th, and the use of soft plastics contributes to the compressive strength on the 28th. However, these characteristics are evaluated by collecting only a part of the waste, and since the deviation of the waste occurs, continuous management is required, and a follow-up study on the environmental problems caused by the use of waste is required.

• Journal of Life Science
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• v.32 no.10
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• pp.771-777
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• 2022

Dopaminergic (DA) cell death in Parkinson's disease (PD) has been attributed to multiple, distinct genetic and environmental factors. In rare familial PD loss of parkin function mutations play a key role in nigral DA neuron-specific pathogenesis primarily via endoplasmic reticulum (ER) stress. In more prevalent sporadic PD, environmental exposure to pesticides has a significant epidemiological role. However, it is largely unknown how environmental exposure to xenobiotics is etiologically linked with the known etiology in familial PD. In the present study biochemical evidence for a common pathogenic mechanism between sporadic and familial PD has been identified employing the recently characterized mesencephalic DA cell line, N27-A. Dieldrin, an organochlorine pesticide epidemiologically implicated in sporadic PD, induced the markers of ER stress response such as a chaperone BiP/Grp78, heme oxygenase-1 and especially, parkin. Accordingly, dieldrin activated the ER resident Caspase-12, a mediator of ER stress-specific apoptosis, during cell death of N27-A cells. Of great interest the dieldrin-induced DA neuronal cell death was synergistically rescued by the overexpression of ER resident neuroprotective proteins, parkin and Bcl-2. The present findings implicate that accumulation of ER stress could be one of common pathogenic mechanisms in idiopathic and familial PD, and some ER proteins, such as parkin and Bcl-2 may effectively attenuate ER stress-mediated N27-A DA cell death.

• Korean Journal of Veterinary Service
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• v.45 no.1
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• pp.47-54
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• 2022

Subcutaneous abscesses, which occur mainly in goats and sheep, are lymph node abscesses caused by Corynebacterium pseudotuberculosis infection, and are divided into internal, external, and mixed types depending on the type of occurrence. While diagnostic methods for subcutaneous abscesses have been continuously studied, research reports for effective treatment and management of subcutaneous abscesses are inadequate. Therefore, this study was conducted to determine the changes in biometric information related to the inflammatory markers of goats induced by subcutaneous abscesses by infection with C. pseudotuberculosis. For this, hematological tests, analysis of inflammatory indicators, and analysis of serum proteins through electrophoresis separation of goats with healthy goats and goats inoculated with C. pseudotuberculosis to induce subcutaneous abscesses were compared and analyzed by date, and the differences and characteristics were identified periodically. As a result, in goats induced with subcutaneous abscesses, anemia findings related to a rapid decrease in red blood cell (RBC), hematocrit (HCT), and hemoglobin (Hb) were observed, and a significant increase in inflammatory cells expressed in total white blood cell (WBC), neutrophil, and monocytes was observed. And the levels of acute phase protein (APP) such as fibrinogen, haptoglobin, and serum amyloid A (SAA) were observed to increase rapidly immediately after infection. In addition, in the results of electrophoretic analysis of serum proteins, it was observed that the levels of α-globulin and β-globulin were significantly increased in goats with subcutaneous abscesses. That is, when looking at these changes, it was found that the systemic inflammatory response of goats was rapidly induced immediately after infection with the C. pseudotuberculosis pathogen. Through this study, it was possible to identify changes in the biomarkers of goats with subcutaneous abscesses, which had not been reported. Furthermore, these analyzed data are thoughts to be of great help in identifying, treating, and managing the goats of subcutaneous abscesses.

• Advances in pediatric surgery
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• v.4 no.1
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• pp.39-47
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• 1998

Infantile hypertrophic pyloric stensosis(IHPS) occurs in three of 1000 live births, and is a major cause of nonbilious vomiting of early infancy. It's etiology and pathogenesis however are still obscure. The operation of pyloromyotomy described by Ramstedt in 1912 remains the standard treatment. From January 1990 to July 1997, 64 infants with IHPS were treated at the Department of Pediatric Sursery, Yeungnam University Hospital. The ratio of male to female was 7:1, and the most prevalent age ranged from 2 weeks to 8 weeks(81.2 %) of age. Fifty-seven infants were first born (57.8 percent). The body weight of all patients at admission was below the 50 percentile. Age of onset of symptoms was between 2 and 4weeks of age in 23 cases(35.9 %). All infants had a history of nonbilious vomting, generally projectile in nature. Hypokalemia was noted in 14 cases(21.9 %) and hypochloremia in 26 cases(40.6 %). In the preoperative ultrasonography, the average muscle thickness, diameter, and length of the pylorus were 6.3 mm, 12.3 mm, and 17.8 mm. A total of 13 associated anomalies were noted in 12 patients. All cases were treated with Fredet-Ramstedt pyloromyotomy. Postoperative wound infection occured in 3 cases. Thirteen cases(20.3 %) presented intermittent nonprojectile vomiting after operation. With control of oral intake vomiting subsided within one week in 63 patients, and in thirteen days in another.

• International Journal of Highway Engineering
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• v.12 no.2
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• pp.107-113
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• 2010

In this study, the relative effects of low-chloride deicier(LCD) and two other deicing agents on the scaling of concrete were conducted in a series of tests at laboratory accordance with the ASTM C 672. The solutions concentration of deicers tested included 1, 4, 10%. Tap water was used as control. The amount of scaling was evaluated gravimetrically. As test result of deicer solution types, when applied to 4% solutions, surface scaling of concrete after 56 freeze-thaw cycles was produced significantly as about 9 times on LCD solution, as about 18 times on $CaCl_2$ solution, and as about 33 times on NaCl solution comparing with tap water. As test result of deicer solution concentrations, relatively low concentrations (of the 4% by weight) of deicer were produced more surface scaling than higher concentrations (of the 10% by weight) or lower concentrations (of the 1% by weight) of deicer. It show that the damaging concentration is of the order of 3~4% for previous research result. It appears that the mechanism of surface scaling is primarily physical rather than chemical. Also, the effect of chloride deicier types, freeze-thaw cycling, and air contents on the performance of concrete was experimentally investigated. The results show that the concrete specimens subjected to freeze-thaw cycling scaled more severely in exposure to deicing salt than those in non-exposure to deicing salt, weight losses of the specimens tested in exposure to deicing salt were twice as much as those tested in non-exposure to deicing salt. Relative dynamic modulus of elasticity of concrete specimens decreased more quickly in exposure to deicing salt than in non-exposure to deicing salt. Also, relative dynamic modulus of elasticity of concrete specimens in exposure to sodium chloride deicing salt was decreased more quickly comparing with exposure to LCD salt. It is also shown that the chloride contents according to concrete specimen depths was more largely in exposure to LCD salt. When concrete specimen is exposed to chloride deicing salts and freeze-thaw cycling, performance degradation in the entrained air concrete(AE concrete) retarded more considerably comparing with non-entrained air concrete(Non-AE concrete).

• Journal of Preventive Medicine and Public Health
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• v.30 no.2 s.57
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• pp.381-391
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• 1997

In an epidemiological study of metal workers exposed to metalworking fluids (MWF), the prevalence time of Evolution, seasonal occurrence and clinical type of contact dermatitis were investigated. Compostional analysis of MWF with HPLC, dermatological examination and two consecutive questionnaire surveys were conducted. Study population was divided into two groups ; workers contact to cutting oil and workers contact to rust preventive oil. In the analysis of MWF, aliphatic hydrocarbons, having 12-20 carbons, was most common composition(49.04%) of cutting oil otherwise, major contents (90.99%) of the rust preventives oil were aliphatic hydrocarbons composed of 6-9 carbons. The frequency (point prevalence) of contact dermatitis(CD) was 7(12.7 per 100 subjects) in the dermatological examination of 55 workers. As the result of second survey for contact dermatitis, cumulative prevalence of oil working full-time and recent 1 year prevalence in two groups were 28.0, 16.7 and 15.1, 12.5 per 100 subjects. There were no difference in the prevalence of CD by oil, age, oil contact duration. Summer is the most common evolution season in workers exposed to cutting oil, but not in workers exposed to rust preventive oil. Major clinical type of CD was erythematous papules in both groups. It presents the importance of preventive measures that 51.1% suffer from contact dermatitis had medical care at their own expense, and 47.1% of them felt serious about their contact dermatitis. From the fact that 68.6% think cotton gloves protective apparatus, we emphasize the need for health education.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1102-1110
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• 2008

This research was performed to analyze the characteristics of wood wastes from origin and to suggest grade-classification for them. Korean proximate analysis was conducted, and heating value, heavy metals and Cl concentrations were analyzed for gradeclassification. Wood wastes were sampled from forest, living, construction and demolition, and industrial areas with origin. Moisture content of most wood wastes was ranged in 5$\sim$10%. VS (volatile solids) and ash contents of them showed > 95% and < 5%, respectively. Most wood wastes except wood for growing mushroom permitted the standard (low heating value $\geq$ 3,500 kcal/kg) for refusederived fuel. CCA (Cr, Cu, As) concentration of wood wastes used in bench, wasted fishing boat, and railroad crosstie was higher than that of the other ones. Cl content showed approximately 1.3% in wood box for fish and $\leq$ 0.2% in the other wood wastes. Cl content of all wood wasted used in this research permitted the standard (Cl $\leq$ 0.2%, dry weight basis) for refuse-derived fuel. If the wood wastes were classified in 3-grade, plywoods would be in 2nd grade, and MDF (medium density fiber), wooden bench, painted electric wire drum, wasted fishing boat, and railroad crosstie be in 3rd grade.