15 results on '"Kang, Chankyu"'
Search Results
2. Fire Risk of Polyethylene (PE)-Based Foam Blocks Used as Interior Building Materials and Fire Suppression through a Simple Surface Coating: Analysis of Vulnerability, Propagation, and Flame Retardancy.
- Author
-
Jeon, Yongtae, Park, Jungwoo, Park, Jongyoung, and Kang, Chankyu
- Subjects
FIREPROOFING ,HEAT release rates ,FLAMMABILITY ,FIREFIGHTING ,CARBON foams ,FIRE prevention ,CONSTRUCTION materials ,FLAME ,SURFACE analysis - Abstract
Building fires can spread through surface combustion of both combustible and interior finishing materials. Recently, the use of foam blocks as interior materials for high-rise residential buildings has increased. However, as foam blocks are primarily composed of polyethylene, they are not flame-retardant and can readily burn and the fire can spread, leading to large-scale damage. Herein, the fire hazard and diffusion characteristics of foam blocks were compared with those of flame-retardant and general wallpapers to confirm the risk of fire. The fire risk of the foam blocks was confirmed using flammability, cone calorimetry, and spread-of-flame analyses. Based on a comparative analysis of the fire risk of foam blocks, the average total heat release was 11.2 MJ/m. This is approximately three times higher than the average heat release rate of the flame-retardant wallpaper and approximately two times higher than that of the general wallpaper. The foam blocks ignited rapidly owing to fire and generated large amounts of combustion gas and heat. To prevent such a fire, 5 wt% montmorillonite (MMT) was simply coated after surface modification to suppress the occurrence of fire. Various flame-retardant materials, surface modifications, and fire safety systems must be developed to prevent fire hazards. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Numerical Investigation of Overtopping Prevention for Optimal Safety Dike Design.
- Author
-
Son, Namjeong, Kim, Yoojin, Min, Mimi, Jung, Seungho, and Kang, Chankyu
- Published
- 2022
- Full Text
- View/download PDF
4. Tracer Gas Test and CFD Analysis of Semiconductor Gas Box for Flammable Gas Leakage.
- Author
-
Kim, Shin-eui, Lee, Kwangho, Kang, Chankyu, and Jung, Seungho
- Subjects
FLAMMABLE gases ,GAS leakage ,GAS analysis ,COMPUTATIONAL fluid dynamics ,GASES ,SEMICONDUCTOR manufacturing - Abstract
Semiconductor manufacturing is performed through unit processes that use various chemicals and facilities. In particular, flammable gases, such as H
2 , NH3 , and CH4 , are used, and there is a risk of explosion when such gases leak. In this study, computational fluid dynamics (CFD) simulation and a "tracer gas test" according to the SEMI (Semiconductor Equipment and Materials International) S6 Environmental, Health, and Safety Guideline for Exhaust Ventilation of Semiconductor Manufacturing Equipment specification were performed during the leakage of hydrogen, a highly flammable gas used in the etching process of a gas box in the semiconductor industry. The CFD simulation was conducted to investigate the safety of semiconductor production facilities in relation to the explosion risk. Flow analysis was performed for the interior of a gas box used in the etching process. A steady-state analysis was performed to predict the concentration range of the explosion limit in the case of continuous hydrogen gas leakage. The interior of the gas box used in the simulation was modeled, and the ventilation flow rate, which has a significant impact on the leakage gas concentration distribution, obtained from experiments was used. The lower flammability limit (LFL) value of the leaked gas was 4% based on H2 , and LFL/4 (25% of the LFL) was analyzed as the explosion limit concentration according to the acceptance criteria of the SEMI S6 tracer gas test. To validate the CFD simulation, a tracer gas test was performed according to SEMI S6. A mixture of hydrogen (5%) and nitrogen (95%) was used as the tracer gas. The flow rate was controlled by a gas regulator valve and measured using an Aalborg mass flow meter. The measured concentration of the tracer gas was calculated using the equivalent release concentration, which was calculated when 100% of the hydrogen was released, and the risk was assessed by comparing it with the LFL/4 of H2 . [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
5. A Study on the Status of Safety and Health for Golf Course Caddies and Improvement of Protective Measures in South Korea.
- Author
-
Lee, Ja-Young and Kang, Chankyu
- Abstract
Due to the rapid expansion of the leisure industry, there were about 32,000 golf caddies in South Korea in 2020, an increase of 18.5% compared to 2016. Consequently, they face an increasing industrial accident rate, which is presumed to be the result of exposure to various harmful factors. Through a survey and oral interview of 221 caddies across more than 20 golf courses, health protective measures, protective measures for caddies, preparation for golf cart operation, physical burden, compliance with golf cart safety during games, and golf course responses to emotional labor were investigated in this study to identify safety and health problems of caddies and suggest prevention measures. Preliminary interviews were conducted to confirm golf courses' safety and health status and participants' characteristics. Golf caddies' health and safety were confirmed using frequency analysis, independent sample t-test, one-way analysis of variance (ANOVA), Pearson correlation analysis, and multiple regression analysis. The results showed that caddies' workplaces were relatively vulnerable to safety and health issues and caddies were exposed to various harmful risk factors. In addition, it was confirmed that golf caddy protective measures, golf cart safety compliance, physical burden, and health protection affect golf courses' response level to caddies' emotional labor. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
6. Analysis of the Complex Causes of Death Accidents Due to Mobile Cranes Using a Modified MEPS Method: Focusing on South Korea.
- Author
-
Kim, Sanghyun and Kang, Chankyu
- Abstract
The convenience and efficiency of mobile cranes are expanding their applicability in industrial sites, but fatal accidents continue to occur as their use increases. There were 56 cases in South Korea from 2015 to 2019, killing 59 workers. To accurately investigate the cause of a fatal accident, accident investigation reports were used. Since they are used not only as the cause of the accident but also as a result of judicial treatment, only direct causes are mentioned. Thus, indirect causes in this study were separately analyzed to induce a complex cause analysis. The man-made, management, economic, physical, political, and social (MEPS) analysis method, developed by the National Institute of Disaster in South Korea, is a type of root cause analysis (RCA), used to derive the fundamental causes of various types of disasters, mainly social ones. The complex causes of fatal accidents were analyzed by applying a modified MEPS method to mobile cranes. The MEPS method investigated three categories, namely man-made, management, and physical factors, among six categories and a newly established level four, to find the root cause of fatal accidents. The analysis results showed that violations of procedures and regulations were the most frequent causes in the man-made factors. A lack of general and special safety education was the most common cause in the management factor, and the overturning, falling, and jamming of the mobile crane were the most frequent causes in the physical factor. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
7. Classification of Human Failure in Chemical Plants: Case Study of Various Types of Chemical Accidents in South Korea from 2010 to 2017.
- Author
-
Jung, Seungho, Pak, Seungkyoo, Lee, Kwanwoo, and Kang, Chankyu
- Published
- 2021
- Full Text
- View/download PDF
8. Risk Assessment Method Combining Independent Protection Layers (IPL) of Layer of Protection Analysis (LOPA) and RISKCURVES Software: Case Study of Hydrogen Refueling Stations in Urban Areas.
- Author
-
Park, Byoungjik, Kim, Yangkyun, Lee, Kwanwoo, Paik, Shinwon, and Kang, Chankyu
- Subjects
CITIES & towns ,RISK assessment ,FUELING ,HYDROGEN as fuel ,HYDROGEN ,HAZARDOUS substances ,SAFETY - Abstract
The commercialization of eco-friendly hydrogen vehicles has elicited attempts to expand hydrogen refueling stations in urban areas; however, safety measures to reduce the risk of jet fires have not been established. The RISKCURVES software was used to evaluate the individual and societal risks of hydrogen refueling stations in urban areas, and the F–N (Frequency–Number of fatalities) curve was used to compare whether the safety measures satisfied international standards. From the results of the analysis, it was found that there is a risk of explosion in the expansion of hydrogen refueling stations in urban areas, and safety measures should be considered. To lower the risk of hydrogen refueling stations, this study applied the passive and active independent protection layers (IPLs) of LOPA (Layer of Protection Analysis) and confirmed that these measures significantly reduced societal risk as well as individual risk and met international standards. In particular, such measures could effectively reduce the impact of jet fire in dispensers and tube trailers that had a high risk. Measures employing both IPL types were efficient in meeting international standard criteria; however, passive IPLs were found to have a greater risk reduction effect than active IPLs. The combination of RISKCURVES and LOPA is an appropriate risk assessment method that can reduce work time and mitigate risks through protective measures compared to existing risk assessment methods. This method can be applied to risk assessment and risk mitigation not only for hydrogen facilities, but also for hazardous materials with high fire or explosion risk. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
9. Case Studies for Dangerous Dust Explosions in South Korea during Recent Years.
- Author
-
Pak, Seonggyu, Jung, Seongho, Roh, Changhyun, and Kang, Chankyu
- Abstract
Despite recent extensive research and technical development to prevent and mitigate dust explosions, processes that produce and handle combustible materials in the form of powders and dusts, either as a main product or as an undesired by-product, have become a constant dust explosion threat as they become more sophisticated and complicated. This study analyzed the characteristics of 53 dust explosions that occurred in South Korea over the last 30 years, and investigated the differences of dust explosions that happened in various countries, such as Japan, the United States, the United Kingdom, and France. In addition, case studies showed the severity of dust explosions occurring in South Korea. Through the special focus on the three most recent years of dust explosions, the causes and processes of the accidents were identified. Analyses of dust explosions in South Korea show that they were mainly caused by organic matter and metal, and, unfortunately, dust explosions occurred repeatedly during grinding, mixing, and injection of powder materials into facilities. No reported accidents occurred during the production processes of wood or paper during the last three years. Taking these characteristics into account, effective ways to prevent or mitigate dust explosions at workplaces where many dust explosions occurred were suggested. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
10. Development of Synergistic Antimicrobial Coating of p-Aramid Fibers Using Ag Nanoparticles and Glycidyltrimethylammonium Chloride (GTAC) without the Aid of a Cross-Linking Agent.
- Author
-
Kang C, Ahn D, Roh C, Kim SS, and Lee J
- Abstract
Functional p-aramid fibers that can express antimicrobial activity were produced by simple processing of silver nanoparticles (AgNPs), which are well known as antimicrobial agents, by using glycidyltrimethylammonium chloride (GTAC), a quaternary ammonium salt. P-aramid fibers were treated with GTAC by the pad-dry-cure process and put into an Ag colloid solution for reactions at 40 °C for 90 min to prepare GTAC/AgNPs-treated p -aramid fibers. Through these processes, GTAC was used as a substitute for existing cross-linking agents. The changes in the degree of attachment of AgNPs to the surface of p -aramid fibers were determined using a scanning electron microscope according to parameters such as GTAC concentration, Ag colloid concentration, and reaction temperature. Through this study, the following results were obtained: (i) The tensile strength of AgNPs/GTAC-treated p -aramid fibers was found to be about 80% of that of untreated p -aramid fibers; (ii) Thermogravimetric analysis showed that the thermal stability of p -aramid fibers did not change much after GTAC/AgNPs treatment and (iii) Antimicrobial activity analysis showed that AgNPs/GTAC-treated p -aramid fibers exhibited superior antibacterial properties compared to untreated p -aramid fibers, which may or may not be the effect of GTAC or AgNPs, or both., Competing Interests: The authors declare no conflict of interest.
- Published
- 2017
- Full Text
- View/download PDF
11. In Vitro Studies on a Microfluidic Sensor with Embedded Obstacles Using New Antibacterial Synthetic Compounds (1-TDPPO) Mixed Prop-2-en-1-one with Difluoro Phenyl.
- Author
-
Roh C, Lee J, Kinger M, and Kang C
- Subjects
- Anti-Bacterial Agents, Biofilms, Microscopy, Confocal, Pseudomonas aeruginosa, Microfluidics
- Abstract
This paper describes the use of an analytical microfluidic sensor for accelerating chemo-repellent response and strong anti-bacterial 1-(Thien-2-yl)-3-(2, 6-difluoro phenyl) prop-2-en-1-one (1-TDPPO). The chemically-synthesized antimicrobial agent, which included prop-2-en-1-one and difluoro phenyl groups, was moving through an optically transparent polydimethylsiloxane (PDMS) microfluidic sensor with circular obstacles arranged evenly. The response, growth and distribution of fluorescent labeling Pseudomonas aeruginosa PAO1 against the antimicrobial agent were monitored by confocal laser scanning microscope (CLSM). The microfluidic sensor along with 1-TDPPOin this study exhibits the following advantages: (i) Real-time chemo-repellent responses of cell dynamics; (ii) Rapid eradication of biofilm by embedded obstacles and powerful antibacterial agents, which significantly reduce the response time compared to classical methods; (iii) Minimal consumption of cells and antimicrobial agents; and (iv) Simplifying the process of the normalization of the fluorescence intensity and monitoring of biofilm by captured images and datasets.
- Published
- 2017
- Full Text
- View/download PDF
12. The Significant Influence of Bacterial Reaction on Physico-Chemical Property Changes of Biodegradable Natural and Synthetic Polymers Using Escherichia coli.
- Author
-
Kang C, Kim S, Kim S, and Lee JW
- Abstract
Escherichia coli (E. coli) was used to activate hydrolysis reaction along with biodegradation in natural and synthetic fibers to identify possibilities as alternative substitutes for textile wastes using chemical solutions and enzymes. To confirm the reaction between the bacterial infections of E. coli and the excessively abundant interstitial spaces of the fibers, various types of natural and synthetic fibers such as cotton, wool, polyethylene terephalate (PET), polyadmide (PA), polyethylene (PE), and polypropylene (PP) were used to confirm the physico-chemical reactions. Tensile strength analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle analysis were used to determine the physico-chemical property changes of the fiber by the bacteria. When biofilm was formed on the fiber surface, various physical changes such as the following were observed: (i) in the analysis of tensile strength, all except PA and PP were decreased and a decrease in cotton fibers was noticeable (ii) depending on the type of fibers, the degree of roughness was different, but generally the surface became rough. In this study, the change of roughness was the most severe on the cotton fiber surface and the change of PET and PA fiber was relatively small. It was found that the intensity peak of oxygen was increased, except for the in cases of PA and PP, through the change of chemical properties by XPS analysis. Changes in topographical properties on the surface through contact angle analysis were stronger in hydrophilic properties, and in the case of cotton, completely hydrophilic surfaces were formed. Through this study, PA and PP fibers, which are Olefin fibers, were theoretically free of physicochemical and topographical changes since there were no functional groups that could trigger the hydrolysis reaction.
- Published
- 2017
- Full Text
- View/download PDF
13. Physical Properties of PDMS (Polydimethylsiloxane) Microfluidic Devices on Fluid Behaviors: Various Diameters and Shapes of Periodically-Embedded Microstructures.
- Author
-
Roh C, Lee J, and Kang C
- Abstract
Deformable polydimethylsiloxane (PDMS) microfluidic devices embedded with three differently-shaped obstacles (hexagon, square, and triangle) were used to examine the significant challenge to classical fluid dynamics. The significant factors in determining a quasi-steady state value of flow velocity ( v )
QS and pressure drop per unit length (∆ P /∆ x )QS were dependent on the characteristic of embedded microstructures as well as the applied flow rates. The deviation from the theoretical considerations due to PDMS bulging investigated by the friction constant and the normalized friction factor revealed that the largest PDMS bulging observed in hexagonal obstacles had the smallest (∆ P /∆ x )QS ratios, whereas triangle obstacles exhibited the smallest PDMS bulging, but recorded the largest (∆ P /∆ x )QS ratios. However, the influence of ( v )QS ratio on microstructures was not very significant in this study. The results were close to the predicted values even though some discrepancy may be due to the relatively mean bulging and experimental uncertainty. The influence of deformable PDMS microfluidic channels with various shapes of embedded microstructures was compared with the rigid microchannels. The significant deviation from the classical relation (i.e., f~1/Re ) was also observed in hexagonal obstacles and strongly dependent on the channel geometry, the degree of PDMS deformation, and the shapes of the embedded microstructures.- Published
- 2016
- Full Text
- View/download PDF
14. The Deformation of Polydimethylsiloxane (PDMS) Microfluidic Channels Filled with Embedded Circular Obstacles under Certain Circumstances.
- Author
-
Roh C, Lee J, and Kang C
- Subjects
- Microfluidics instrumentation, Pressure, Dimethylpolysiloxanes chemistry, Microfluidics methods, Models, Theoretical
- Abstract
Experimental investigations were conducted to determine the influence of polydimethylsiloxane (PDMS) microfluidic channels containing aligned circular obstacles (with diameters of 172 µm and 132 µm) on the flow velocity and pressure drop under steady-state flow conditions. A significant PDMS bulging was observed when the fluid flow initially contacted the obstacles, but this phenomenon decreased in the 1 mm length of the microfluidic channels when the flow reached a steady-state. This implies that a microfluidic device operating with steady-state flows does not provide fully reliable information, even though less PDMS bulging is observed compared to quasi steady-state flow. Numerical analysis of PDMS bulging using ANSYS Workbench showed a relatively good agreement with the measured data. To verify the influence of PDMS bulging on the pressure drop and flow velocity, theoretical analyses were performed and the results were compared with the experimental results. The measured flow velocity and pressure drop data relatively matched well with the classical prediction under certain circumstances. However, discrepancies were generated and became worse as the microfluidic devices were operated under the following conditions: (1) restricted geometry of the microfluidic channels (i.e., shallow channel height, large diameter of obstacles and a short microchannel length); (2) operation in quasi-steady state flow; (3) increasing flow rates; and (4) decreasing amount of curing agent in the PDMS mixture. Therefore, in order to obtain reliable data a microfluidic device must be operated under appropriate conditions.
- Published
- 2016
- Full Text
- View/download PDF
15. Production of anti-cancer agent using microbial biotransformation.
- Author
-
Roh C and Kang C
- Subjects
- Fermentation, Gas Chromatography-Mass Spectrometry, HeLa Cells, Humans, Hydroxylation, Neoplasms metabolism, Resveratrol, Streptomyces classification, Streptomyces metabolism, Antineoplastic Agents metabolism, Biotransformation, Neoplasms drug therapy, Stilbenes metabolism, Streptomyces growth & development
- Abstract
Microbial biotransformation is a great model system to produce drugs and biologically active compounds. In this study, we elucidated the fermentation and production of an anti-cancer agent from a microbial process for regiospecific hydroxylation of resveratrol. Among the strains examined, a potent strain showed high regiospecific hydroxylation activity to produce piceatannol. In a 5 L (w/v 3 L) jar fermentation, this wild type Streptomyces sp. in the batch system produced 205 mg of piceatannol (i.e., 60% yields) from 342 mg of resveratrol in 20 h. Using the product, an in vitro anti-cancer study was performed against a human cancer cell line (HeLa). It showed that the biotransformed piceatannol possessed a significant anticancer activity. This result demonstrates that a biotransformation screening method might be of therapeutic interest with respect to the identification of anti-cancer drugs.
- Published
- 2014
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.