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[Display omitted] Risk management of major hazardous installations (MHIs) is a principal concern due to chemical hazards, both in South Korea and in foreign countries where chemical plants are located. To cope with these risks, various regulatory schemes have been developed for the recognition, prevention, and control of chemical accidents. Despite these efforts, the worst major accident caused by massive (20 t) leakage of anhydrous hydrogen fluoride occurred in Gumi City in 2012. As a result, the location of MHIs associated with the chemical industry became a major concern among the public, relating to the risks to both the public and environment. In this study, the regulatory systems in South Korea are compared with global standards for controlling major hazards, and the adoption of land use planning (LUP) is discussed. Based on population statistics for the last 17 years, the EPA's ALOHA software was used to evaluate the impact of land development and population growth around MHIs through case studies of societal risk changes at five water-treatment plants using Cl 2 (chlorine). The total risk at the Cl 2 sites increased by up to 3.05 times from 2000 to 2017, demonstrating the necessity of introducing LUP. [ABSTRACT FROM AUTHOR]

Understanding the mechanical properties of optically transparent polydimethylsiloxane (PDMS) microchannels was essential to the design of polymer-based microdevices. In this experiment, PDMS microchannels were filled with a 100 μM solution of rhodamine 6G dye at very low Reynolds numbers (∼10-3). The deformation of PDMS microchannels created by pressure-driven flow was investigated by fluorescence microscopy and quantified the deformation by the linear relationship between dye layer thickness and intensity. A line scan across the channel determined the microchannel deformation at several channel positions. Scaling analysis widely used to justify PDMS bulging approximation was allowed when the applied flow rate was as high as 2.0 μl/min. The three physical parameters (i.e., flow rate, PDMS wall thickness, and mixing ratio) and the design parameter (i.e., channel aspect ratio = channel height/channel width) were considered as critical parameters and provided the different features of pressure distributions within polymer-based microchannel devices. The investigations of the four parameters performed on flexible materials were carried out by comparison of experiment and finite element method (FEM) results. The measured Young's modulus from PDMS tensile test specimens at various circumstances provided reliable results for the finite element method. A thin channel wall, less cross-linker, high flow rate, and low aspect ratio microchannel were inclined to have a significant PDMS bulging. Among them, various mixing ratios related to material property and aspect ratios were one of the significant factors to determine PDMS bulging properties. The measured deformations were larger than the numerical simulation but were within corresponding values predicted by the finite element method in most cases. [ABSTRACT FROM AUTHOR]

Semiconductor manufacturing is performed through unit processes that use various chemicals and facilities. In particular, flammable gases, such as H2, 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]

The number of pressure vessel bursts (PVBs) has reduced since the 1990s due to the introduction of many rules and regulations. However, accidents frequently occur during pressure resistance tests (pneumatics) and there are scant safety guidelines for examining pressure vessels. Thus, this study proposes a safe distance to prevent accidents during a test, based on the explosion energy and vessel shape. First, the maximum explosion energy was computed using Brode's equation and the distance and overpressure were nondimensionalized via Sachs' scaling. Next, the overpressure ratio of the spherical tank (opsphere) was calculated based on the overpressure ratio of the cylindrical tank (opcylinder), considering the length to diameter ratio of the cylindrical vessel. Finally, the function of the safety distance was obtained. The result was validated by comparing it with data from the catastrophic failure that occurred at D. D. Williamson & Co. Inc. in 2003. This study could help establish safety guidelines and the prevention of PVB damage. [ABSTRACT FROM AUTHOR]

• An analysis of the industrial accident prevention effect of the hazardous machine safety certification system was performed. • The necessity of the safety certification system was confirmed using three statistical methods. • Surveys, industrial accident data analysis, field surveys, and expert interviews were conducted. • It was confirmed that the safety certification system has a positive effect on industrial accident prevention. • The safety certification system must ensure efficiency by considering the safety policy and industrial environment of each country. The "4th industrial revolution" is accelerating changes in technology, industry, and machinery, and the "Internet of everything" (IoE) requires comprehensive integration of people and machines. Despite the development of these technologies, fatal accidents continue to occur due to malfunctions of dangerous machinery, so the importance of the safety certification system is increasing, but there are few objective analysis data. In this study, the necessity of a safety certification system was confirmed by analyzing the effect of the safety certification system on the prevention effect of industrial accidents in three methods. Based on these analysis results, the industrial accident prevention effect of the current safety certification system and necessary supplementary tasks were derived. Safety certification systems for more than 30 machines and equipment are in operation in South Korea. In this research, the press, crane, catapult, and lift machines most commonly used in industrial fields were analyzed. This study was conducted in five steps: a safety certification system operation status investigation, a survey and interviews, an analysis of dangerous machinery and equipment accidents, focus group interviews, and study of the direction of safety certification systems in consideration of recent IoE developments. As a result of the analysis, various opinions were presented on the safety certification system by subject, and it was found that it was necessary to prepare supplementary measures for the advancement of the safety certification system advancement, expand its field applicability, and improve the efficiency of safety certification. [ABSTRACT FROM AUTHOR]

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]

Wool and polyester blends are sensitive to heat and pose fire hazards. In this study, the flame retardancy of wool/polyester blended fabric was improved by coating montmorillonite (MMT) and polyquaternium-10 (PQ-10) using the layer-by-layer assembly (LBL) method. This was done to confirm the feasibility of combining eco-friendly materials such as MMT and PQ-10 coatings and to secure the flame retardancy of the wool/polyester blend. The phosphate-buffered solution enhanced the intermolecular forces during pretreatment. Scanning electron microscopy and Fourier-transform infrared spectroscopy analyses confirmed the successful deposition of the MMT/PQ-10 combination on the fabric, and the deposition on the fabric surface increased as the number of coating layers increased. The thermogravimetric analysis results showed that the MMT/PQ-10 combination effectively reduced the maximum decomposition temperature, contributing to improved high-temperature thermal stability. Additionally, compared with the untreated fabrics, the coated fabrics exhibited a 38.2% increase in residual substances, and flame-retardant properties enhanced up to 27.3%. As a result of the vertical flame test, the MMT/PQ-10 combination improves the cohesiveness of the fabrics and prevents melt dripping, contributing to the improvement of flame retardancy. [Display omitted] • Eco friendly flame-retardant coating was applied to wool/polyester fabric through Layer-by-Layer process. • The use of phosphate buffer improved interlayer bonding strength. • The combination of MMT/PQ-10 effectively improved the thermal stability of the fabric at high temperatures. • the coated fabrics exhibited a 38.2% increase in residual substances and flame-retardant properties enhanced up to 27.3%. • The melt drop phenomenon was eliminated from the treated fabrics. [ABSTRACT FROM AUTHOR]

The advent of eco-friendly hydrogen vehicles has prompted attempts to increase the installation of hydrogen refueling stations in urban areas; however, sufficient safety measures have yet to be established. Gas plume dispersion, jet flame, and heat flux were investigated using HyRAM software by considering accidents at hydrogen refueling stations in reports published by Sandia National Laboratories. Hydrogen release and jet flame length were measured using the Schlieren imaging system and a thermal imaging camera. The HyRAM simulation analysis results were more conservative than the experimental results. These showed that the pressure and leak diameter greatly influenced the safety of hydrogen facilities. Individual and societal risks were analyzed through RISKCURVES, and the risks were found to be highest in the sidewalk and dispenser. An F-N (Frequency- Number of fatalities) curve to verify the risk of installing a hydrogen refueling station in urban areas was derived, and the safety distance from residents was proposed. [Display omitted] [ABSTRACT FROM AUTHOR]

• Industrial accidents caused by equipment (machinery) occur in various forms, such as jamming, cutting, and crushing. • Many fatal accidents, mainly due to jamming, occurred in non-routine work. • Non-routine work accounted for 56.5% of jamming accidents, which were caused by seven major equipment. • The maintenance, repair, inspection, replacement, adjustment, cleaning, and removal of foreign substances were classified into non-routine work. • The main cause was that the work was done without stopping the operation of equipment. Industrial accidents caused by equipment (machinery) occur in various forms, such as jamming, cutting, and crushing. Among them, various precise and dangerous machines and equipment in the manufacturing industry continue to be used despite the several regulations established and efforts made. This study analysed the accidental deaths caused through jamming or crushing during non-routine work, in the manufacturing industry from 2014 to 2018. The analysis was conducted on 203 cases of non-routine work among 359 fatalities. The maintenance, repair, inspection, replacement, adjustment, cleaning, and removal of foreign substances were classified into non-routine work. Owing to the use of various machineries and equipment in the manufacturing industry, specialised knowledge is required for their maintenance and management, as well as daily work. Since various types of equipment (machinery) are used in the manufacturing industry, expertise to safely use equipment is required to prevent industrial accidents that may occur during work using this equipment. In South Korea, where heavy industry and chemical industry have developed, many accidental deaths due to non-routine work have been reported under these conditions. Non-routine work accounted for 56.5% of jamming accidents, which were caused by seven major equipment such as conveyor, mixer, food manufacturing equipment, crushing machine, injection moulding machine, press machine, and industrial robot. In addition, the employees did not fully comply with the basic safety rules, such as not turning off the power or using lockout-tagout (LOTO), during the maintenance work. Finally, various measures were proposed to prevent accidental deaths resulting non-routine work. [ABSTRACT FROM AUTHOR]

• This study investigates chemical accidents that occurred between January 2008 and June 2018 in South Korea. • 76.1% of chemical accidents were caused by human error in South Korea. • Large-scale enterprises experienced the largest number of industrial accidents during maintenance work. • Fire and explosion accounted for 72% of all CPI accidents, of which 32.4% were ignited by static electricity. • Chemical accidents mostly occurred in storage tanks, chemical reactors, and mixing tanks. Major accidents in the chemical process industries are relatively rare, but the resulting harm to workers, property loss, business interruption, and the environment are very serious. This study investigates chemical accidents that occurred between January 2008 and June 2018 in South Korea, and proposes ways to prevent similar accidents from occurring by analyzing the main causes of these accidents. Nine core concepts were drawn from the analyses comparing chemical accidents in South Korea: (1) current casualties by type of worker, (2) how the scale of the enterprise affects the disaster, (3) chemical accidents by type of occurrence, (4) analysis of ignition sources, (5) chemical accidents by CPI facilities, (6) human and technical error, (7) chemical accidents by work situation, (8) chemical accidents by non-compliance of process safety management (PSM) standards, and (9) chemical accidents by hazardous materials. Although there have been no recent occurrences of large chemical accidents since 2017 due to various factors, our results indicate that the past frequency of such accidents area serious concern in South Korea. Understanding the root causes of these accidents can help to prevent the recurrence of similar accidents and to strengthen preventative measures in chemical plants. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • PI/ p -aramid composite yarns formed through the stepwise coating to improve heat resistance. • The pyrolysis temperature of PI / p -aramid yarn after heat treatment at 350 °C was higher than that of existing p -aramid yarn. • The imidization of PI is affected by temperature, heat treatment time, and catalyst usage. • The PI / p -aramid coated yarn improved tensile strength. • Long-term exposure to 250 °C is required to improve physical and chemical properties of the p -aramid yarn. Abstract With excellent heat resistance and chemical resistance, p -aramid is used in a variety of industrial applications. In this study, the polyimide (PI) precursor was coated on the surface of p -aramid yarn and studied the changes in heat resistance and physicochemical properties of composite PI / p -aramid yarns. Changes in peaks by imidization of PI using XRD and FT-IR, surface characteristics through SEM, and thermal properties analyzed by TMA and TG-DTA were measured. The degree of imidization of PI films were quantitatively investigated by FT-IR analysis. Through these analyzes, the following results were revealed: (1) the imidization of the PI was confirmed that the thermal imidization process at 350 °C was suitable; (2) the physical properties of the PI film were affected by the imidization temperature, the heat treatment time and the amount of the catalyst; and (3) the tensile strength of PI / p -aramid coated yarn was higher than that of conventional uncoated p -aramid yarn at 200–350 °C. Therefore, PI/ p -aramid composite yarns formed through the stepwise coating were found to improve thermal properties including initial thermal degradation temperature compared to no PI coating. [ABSTRACT FROM AUTHOR]

Chemical disinfectants, widely used as antibacterial criteria, have been extensively studied for the past few decades by being divided into three levels, and γ-irradiation is also currently recognized as an outstanding antibacterial technique. However, there is no correlation between the strengths of the two methods. Antibacterial efficacy and tensile strengths of various natural and synthetic polymers inoculated with Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) were analyzed using SEM, FT-IR, and tensile strength instruments. High and medium-level chemical disinfectants showed a similar effect to 2 kGy and 0.5 kGy of γ-irradiation doses for antibacterial analysis. In addition, the degradation of material properties through tensile strength analysis was observed only with high-level chemical disinfectants. When the correlation of high-level chemical disinfectants and γ-irradiation doses was compared through analysis of tensile strength, high-level chemical disinfectants exhibited a result equivalent to a 0.5 kGy γ-irradiation dose for synthetic polymers, while natural polymers were observed to be similar to 5 kGy for cotton and 50 kGy for wool, respectively. [ABSTRACT FROM AUTHOR]

Supercapacitors have attracted considerable attention because they can store more energy than conventional capacitors and can have higher power densities than batteries. In this study, microwave irradiation was used for the rapid and facile synthesis of mesoporous RGO@(Co,Mn) 3 O 4 oxide nanosheets as an electrode material for supercapacitor applications. The as-prepared electrode exhibited a high capacitance of 1004 F g −1 at 3 mV s −1 in a 6 M KOH electrolyte solution. Moreover, the electrode showed good specific retention and high Coulombic efficiency of 81.6% and 96.9%, respectively, after 3000 charge-discharge cycles. The electrode also exhibited a high energy density of 53 Wh kg −1 (at power density of 500 W kg −1 ) and high power density 5000 W kg −1 (at energy density of 27 Wh kg −1 ). Overall, the RGO@(Co,Mn) 3 O 4 electrode showed very promising results for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Obesity is the fifth leading cause of death globally. At least 2.8 million adults die each year as a result of being overweight. Therefore, the development of an efficient lipid inhibitor for the biological effects of obesity is highly needed. The discovery of bioactive compounds from food is one possible way to control obesity and to prevent or reduce the risks of various obesity-related diseases. In this study, we found that 7,3′,4′-trihydroxyisoflavone from Korean soybean paste has remarkable anti-obesity activity in vitro and in vivo. Treatment with 7,3′,4′-trihydroxyisoflavone significantly reduced the adipose tissue weight to 1.6/100 g of body weight in high-fat mice. In addition, in 7,3′,4′-trihydroxyisoflavone-treated mice, a significant reduction in the serum triglyceride and T-cholesterol was observed at 29 and 37 %, respectively. These results support the hypothesis that 7,3′,4′-trihydroxyisoflavone is expected to create a therapeutic interest in its use for the treatment of obesity. [ABSTRACT FROM AUTHOR]

A less-toxic and durable flame-retardant treatment for cotton fabrics was developed using a blocked isocyanate (MDI), citric acid (CA) as a cross-linker, and 3-(dimethylphosphono)-N-methylolpropionamide (MDPPA) as a fire-retardant agent. Treated samples were prepared using the pad–dry–cure method, in which cotton fabric samples were immersed in solutions containing various ratios of MDPPA/CA/MDI. The chemical structures of the treated cotton fabrics, as well as the flame retardancy, thermal stability, physicochemical properties, and durability of the flame-retardant effect to washing, were investigated. The treated cotton fabrics showed different flame retardancies depending on the ratio of components in the flame-retardant treatment, and, thus, the optimal ratio was determined. Using Fourier transform infrared and X-ray photoelectron spectroscopy analyses, we confirmed that MDPPA was attached to the cotton fibers. In addition, vertical flame-retardancy tests were performed on samples before and after washing and the limiting oxygen index values were obtained. Based on the tests, the sample treated with a mixture containing 400, 40, and 50 g/L of MDPPA, CA, and MDI, respectively, showed the best fire resistance, even after 50 washing cycles, and the tear strength, crease recovery angle, and flame retardancy were all improved compared to those of the untreated sample. [Display omitted] • Three chemicals such as MDI, CA, and MDPPA were applied on cotton to increase flame retardancy. • The thermal and physicochemical properties produced by the pad-dry-cure process were assessed by TGA, FT-IR. • The ratio of the mixed solutions of the three components affects the flame retardancy of cotton. • Flame-retardant durability was maintained even in 50 washings. • Washing durability and tear strength increased due to the urethane reaction. [ABSTRACT FROM AUTHOR]

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]

[Display omitted] • Various elongation rates (50%, 100%, and 125%) improved physicochemical properties. • C-Cl peak disappears and C = C peak appears depending on the effect of carbonization. • CPVC carbon fiber with an elongation of 125% showed maximum mechanical properties. • CPVC carbon fiber with a tensile strength of 1.83 GPa can be applied to the automotive industry. CPVC fibers were prepared using a low-cost chlorinate polyvinyl chloride (CPVC) precursor using wet spinning, and various elongation rates were applied (0%, 50%, 100%, and 125%) to improve the physicochemical properties. CPVC fibers were carbonized in a nitrogen atmosphere to prepare CPVC carbon fibers, and physicochemical changes were observed by applying the same elongation rates. The CPVC fiber changed from aliphatic to aromatic carbon chemically, such as C-Cl peak intensity disappeared after carbonization and C = C bonding peak was newly discovered. After CPVC carbonization, CPVC carbon fiber, which has an elongation of 125%, has the maximum mechanical properties (tensile strength of up to 1.83GPa, modulus of 172GPa) by inducing a change in the carbon fiber structure, so it can be applied to the automotive industry in the future. [ABSTRACT FROM AUTHOR]

• Physiochemical property changes of PET fibers after supercritical (SC) CO 2 dyeing. • PET crystal orientation and crystal index of fibers increased by adding DR 167 dye. • After SC–CO 2 dyeing, some PET fiber C‒C bonds break and new C=O and C‒O bonds form. • SC–CO 2 -treated PET with DR 167 dye increases fiber tensile strength. ga1 The effects of supercritical CO 2 and C.I. Disperse Red 167 as media on the structural and chemical properties of polyethylene terephthalate (PET) fibers were observed in the supercritical dyeing process of these fibers using numerous methods to predict changes in their physical properties. PET samples were classified into three cases based on the sample preparation and analysis steps. When the PET fibers were treated without C.I. Disperse Red 167 under a supercritical fluid CO 2 solvent at 120 °C and 25 MPa, their crystallinity, orientation, and tensile strength decreased the most among the three cases, whereas when they were treated with C.I. Disperse Red 167 under the same conditions, the three above-mentioned characteristics were relatively improved compared to the scenario without the C.I. Disperse Red 167 treatment. These experimental results provided significant information on the effects of supercritical CO 2 and C.I. Disperse Red 167 on the properties of PET fiber polymers. [ABSTRACT FROM AUTHOR]