• Journal of Environmental Health Sciences
• /
• v.48 no.5
• /
• pp.272-281
• /
• 2022

Background: The constant consumption of chemical products owing to expanding industrialization has led to an increase in public interest in chemical substances. As the production and disposal processes for these chemical products cause environmental problems, regional information on the hazard level of chemical substances is required considering their effects on humans and in order to ensure environmental safety. Objectives: This study aimed to identify hazard contribution and spatiotemporal characteristics by region and chemical by calculating a hazard-based result score using pollutant release and transfer register (PRTR) data. Methods: This study calculated the chemical discharge and hazard-based result score from the Risk-Screening Environmental Indicators (RSEI) model, analyzed their spatiotemporal patterns, and identified hotspot areas where chemical discharges and high hazard-based scores were concentrated. The amount of chemical discharge and hazard-based risk scores for 250 cities and counties across South Korea were calculated using PRTR data from 2011 to 2018. Results: The chemical discharge (high densities in Incheon, Daegu, and Busan) and hazard-based result scores (high densities in Incheon, Chungcheongnam-do, and some areas of Gyeongsangnam-do Province) showed varying spatial patterns. The chemical discharge (A, B) and hazard-based result score (C, D) hotspots were identified. Additionally, identification of the hazard-based result scores revealed differences in the type of chemicals contributing to the discharge. Ethylbenzene accounted for ≥80% of the discharged chemicals in the discharge hotspots, while chromium accounted for >90% of the discharged chemicals in the hazard-based result score hotspots. Conclusions: The RSEI hazard-based result score is a quantitative indicator that considers the degree of impact on human health as a toxicity-weighted value. It can be used for the management of industries discharging chemical substances as well as local environmental health management.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2005.11a
• /
• pp.231-233
• /
• 2005

• Korean Chemical Engineering Research
• /
• v.58 no.2
• /
• pp.171-175
• /
• 2020

In the proton exchange membrane fuel cells (PEMFC), the development of a reinforced membrane with improved durability by a support is actively in progress in Korea. In this study, the initial performance and characteristics of four types of reinforced membranes were compared. Reinforced membranes with higher amounts of C-F chains in the polymer membrane showed lower water diffusion coefficients due to the hydrophobicity of the C-F chains. The thicker the polymer membrane, the more the hydrogen permeability decreased and the higher the OCV. Membrane with short resistance below 1.5 Ωcm² showed OCV below 0.9 V and the lowest performance, so short resistance should be above 3.0 Ωcm². Compared with the current standard membrane, there was a similar domestic membrane, which could confirm the possibility of localization of PEMFC polymer membrane.

• Journal of Adhesion and Interface
• /
• v.14 no.3
• /
• pp.146-159
• /
• 2013

In the present study, stabilized rayon fabrics were prepared from fast isothermal stabilization processes, which were carried out within four minutes at $350^{\circ}C$. The effects of ultrasonic cleaning and chemical pre-treatment on the chemical composition, physical characteristics, X-ray diffraction pattern, thermal stability and shape of the stabilized rayon fabrics were investigated extensively. In order to reduce the weight loss and thermal shrinkage of rayon fabrics occurring during the stabilization process, ultrasonic cleaning was first conducted and then chemical pre-treatments using $NH_4Cl$, $Na_3PO_4$, $H_3PO_4$, and $ZnCl_2$ were performed, respectively. The results indicated that both ultrasonic cleaning and chemical pre-treatment influenced the weight loss, thermal shrinkage, microstructure, carbon content, thermal stability and fabric shape of stabilized rayon fabrics. Also the results depended on the fast-stabilization time and the type of chemical pre-treatment agents used.

• Journal of the Korean Society of Safety
• /
• v.34 no.2
• /
• pp.48-55
• /
• 2019

For preventing the accidents generated from the chemical materials, thus far, MSDS (Material Safety Data Sheet) data have been made to notify how to use and manage the hazardous and chemical materials in safety. However, it is difficult for users who handle these materials to understand the MSDS data because they are only listed based on the alphabetical order, not based on the specific factors such as similarity of characteristics. It is limited in representing the types of chemical materials with respect to their characteristics. Thus, in this study, a lots of MSDS data are visualized based on relationships of the characteristics among the chemical materials for supporting safety managers. For this, we used the textmining algorithm which extracts text keywords contained in documents and the Self-Organizing Map (SOM) algorithm which visually addresses textual data information. In the case of Occupational Safety and Health Administration (OSHA) in the United States, the guide texts contained in MSDS documents, which include use information such as reactivity and potential risks of materials, are gathered as the target data. First, using the textmining algorithm, the information of chemicals is extracted from these guide texts. Next, the MSDS map is developed using SOM in terms of similarity of text information of chemical materials. The MSDS map is helpful for effectively classifying chemical materials by mapping prohibited and hazardous substances on the developed the SOM map. As a result, using the MSDS map, it is easy for safety managers to detect prohibited and hazardous substances with respect to the Industrial Safety and Health Act standards.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 1993.11a
• /
• pp.78-81
• /
• 1993

AN EXTENSIVE RESEARCH AND DEVELOPMENT WORK WILL BE CARRIED OUT FOR THE COMMERCIALIZATION OF THE CHEMICAL HEAT PUMP SYSTEM WHICH BASED ON THE ELF AQUITAINE FRANCE PATENTED AND KIME LICENSED SOLID/GAS CHEMICAL REACTION TECHNOLOGY. TOWARD ON THAT GOAL, THE BASIC AND ENGINEERING DETAILS SUCH AS IMPEX BLOCK MATERIAL, PHYSICO-CHEMICAL AND THERMO-CHEMICAL CHARACTERISTICS OF REACTION MECHANISMS IN THE SOLID/GAS CHEMICAL REACTION HEAT PUMP SYSTEMS. THREE KIND OF APPLICATION SYSTEM ARE NOW INVESTIGATED; AIR CONDITIONING, REFRIGERATOR AND INDUSTRIAL PROCESS HEATING AND COOLING SYSTEM.

• Journal of Hydrogen and New Energy
• /
• v.6 no.2
• /
• pp.85-90
• /
• 1995

Activation behavior, hydriding rate and disintegration were tested for hydrogen storage alloy particles fixed in an adhesive after treating with inorganic solution. Commertial adhesive as a binder was used. Chemical-treated particles showed the best characteristics for activation and a little effect of prevention the break down of the powders themselves after several repeated operations. Furthermore activation characteristics were found to show a similar trend to chemical-treated powders even in the fixed one with an adhesive, except for a slight decrease in reaction velocity.

• The Korean Journal of Food And Nutrition
• /
• v.8 no.3
• /
• pp.184-191
• /
• 1995

This study was designed to investigate the changes In chemical characteristics of traditional kochujang increase in fermentation time, whereas that of total sugar decreased rather rapidly during aging of meju. Amino nitrogen content of meju Increased sharply up to 40 days of fermentation and then decreased there after On the other hand, ammoniacle nitrogen content continued to increase with increasing aging time. Initially, maltose was the most abundant free sugar, but was later replaced by glucose or fructose as the fermentation proceeded. Among non-volatile organic acids, pyroglutamic acid was present at an appreciably other organic acids did not change considerably during fermentation. The total free amino acid content Increased up to 40th day of aging and then decreased thereafter The was the most abundant amino acid followed in decreasing order by Try and Glu in meju fermented for 40 days.

• Journal of the Korean Chemical Society
• /
• v.12 no.4
• /
• pp.155-159
• /
• 1968

On the extraction of humic acid from peat, the optimum conditions were studied and the effects of them on the characteristics of humic acid were also examined by means of infrared spectroscopy. 1. Pretreatment of peat with diluted 6-8% HCl solution for 5 hrs. prior to extraction with alcohol-benzol azeotropic mixture have resulted the better yield of humic acid. The water soluble Na-humates were obtained by the subsequent extraction with one hundred times quantity of caustic soda solutieon for 1hr. at 90 $^{\circ}C$. Thus the pure humic acids have been yielded approximately 40% (by wt.) from the raw peat. 2. In characteristics of humic acid, the chemical structure, mainly the contents of such functional groups as -COOH, -OH (phenol type), $-CH_2CO-$, $-CH_2{\cdot}O{\cdot}CH_2-$ and aromatic rings were varied according to the concentration of alkaline solution, temperature and time when the humic acids were extracted with alkali.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.16 no.6
• /
• pp.465-470
• /
• 2003

The chemical mechanical polishing (CMP) process has been widely used for the global planarization of multi-layer structures in semiconductor manufacturing. The CMP process can be optimized by several parameters such as equipment, consumables (pad, backing film and slurry), process variables and post-CMP cleaning. However, the COO(cost of ownership) is very high, because of high consumable cost. Especially, among the consumables, the slurry dominates more than 40 %. In this paper, we have studied the CMP characteristics of diluted silica slurry by adding of raw alumina abrasives and annealed alumina abrasives. As an experimental result, we obtained the comparable slurry characteristics compared with original silica slurry in the view-point of high removal rate and low non-uniformity. Therefore, we can reduce the cost of consumables(COC) of CMP process for ULSI applications.