• The Journal of Natural Sciences
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• v.5 no.1
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• pp.67-75
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• 1992

In the our country, especially in Yeongil and Wolsung area, abundant authigenic zeolites are found from the tuffaceous sediments and volcanic rocks of Miocene age showing wide variation in their mineralogy and abundance from horizon to horizon. The principal zeolite species identified are clinopti-lolite. mordenite. heulandite. ferrierite, and erionite. etc. Zeolite minerals are widely used in many countries in the following applications; (a) in air separation adsorption processes; (b)as desiccants; (c)in inorganic building materials; (d)in papermaking; (e)in fertilizers; (f)as soilconditioners-this application is based upon the ability of the zeolite to ion exchange with soil nutrients; (g)in the treatment of radioactive wastes; and (h)as adsorbents for toxic gases, etc. In the present paper, using natural zeolite mordenite treated with IN hydrochloric acid or IN sodium chloride solution as column packings, separation characteristics of argon, nitrogen, carbon monoxide, and methane gases have been studied by gas chromatography. By the use of mordenite treated with hydrochloric acid solution, the tailing peak of methane showed from untreated mordenite was satisfactorily reduced, although it was difficult to separate it from carbon monoxide with a column activated at $300^{\circ}C$. Using a column activated at $350^{\circ}C$, methane could be separated from carbon monoxide easily but only carbon monoxide eluted as a bad defined peak. Mordenite treated with sodium chloride solution was generally similar to chromatograms obtained by using the untreated mordenite. Both the above chemical treatments of mordenite had little effect on the separations of argon and nitrogen. The separations and the HETP values obtained from natural zeolite mordenite treated with continuously hydrochloric acid and sodium chloride solutions were almost identical with those obtained with synthetic molecular sieve 5A zeolite. On the other hand, the efficiency of column was good in the range 20~3Oml/min of the carrier helium gas rate.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.38-41
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• 2008

In this research, we propose a new method for tracking the release rate using the concentration data obtained from the sensor. We used a sensor network that has already been set surrounding the area where hazardous gas releases can occur. From the real-time sensor data, we detected and analyzed releases of harmful materials and their concentrations. Based on the results, the release rate is estimated using the neural network. This model consists of 14 input variables (sensor data, material properties, process information, meteorological conditions) and one output (release rate). The dispersion model then performs the simulation of the expected dispersion consequence by combining the sensor data, GIS data and the diagnostic result of the source term. The result of this study will improve the safety-concerns of residents living next to storage facilities containing hazardous materials by providing the enhanced emergency response plan and monitoring system for toxic gas releases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.132-137
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• 2018

Although the number of chemical accidents has been declining since the Chemical Control Act of 2015, there have been repeated occurrences of similar types of accidents at printed circuit board (PCB) manufacturing facilities. These accidents were caused by the overflow of hydrochloric acid and hydrogen peroxide, which are toxic chemicals used in the printed circuit board manufacturing process. An analysis of the $Cl^-$ content to identify the cause of the accident showed that in the mixed route of hydrochloric acid and hydrogen peroxide, which are accidental substances, the $Cl^-$ concentration was 66.85 ppm in the hydrogen peroxide sample. Through reaction experiments, it was confirmed that the deformation of a PVC storage tank and generation of chlorine gas, which is a toxic gas, occurred due to reaction heat occurring up to $50.5^{\circ}C$. This paper proposes a facility safety management plan, including overcharge, overflow prevention, leak detection device, and separation tank design for mixing prevention in printed circuit board manufacturing facility etch process. To prevent the recurrence of accidents of the same type, the necessity of a periodic facility safety inspection and strengthening of the safety education of workers was discussed.

• Fire Science and Engineering
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• v.30 no.4
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• pp.65-72
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• 2016

This study examined the generation of combustion toxic gases of pinus rigida specimens processed with bis-(dimethylaminomethyl) phosphinic acid (DMDAP), bis-(diethylaminomethyl) phosphinic acid (DEDAP), and bis-(dibutylaminomethyl) phosphinic acid (DBDAP). Each pinus rigida plate was coated three times with 15 wt.% flame retardants in an aqueous solution. The specimens were then dried at room temperature. The production of combustion toxic gases was investigated using a cone calorimeter (ISO 5660-1). The first time to peak mass loss rate ($1^{st}-TMLR_{peak}$) processed with the chemical additives decreased to 5.9 from 41.2% compared with the unprocessed specimen. The second time to the peak mass loss rate ($2^{nd}-TMLR_{peak}$) for the processed specimens was decreased 1.8% for DMDAP and 5.3% for DBDAP and increased 1.8% for DEDAP. The peak carbon monoxide ($CO_{peak}$) production was 1.5 to 2.0 times higher than that of the unprocessed plate. The peak carbon dioxide ($CO_{2peak}$) production was reduced 0.01 times for DMDAP and increased 1.15 to 1.19 times for DEDAP and DBDAP compared with the unprocessed specimens. In particular, the oxygen concentration was much higher than 15%, which can be fatal to humans and the resulting hazard can be eliminated. Overall, the combustion toxicity of flammable gas were increased partially by the chemical additives compared with those of the unprocessed plate.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.532-538
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• 2006

The carbonization and activation conditions for the PAN-based ACF of various grade were investigated to obtain the optimun activation condition with high surface area. And the surface properties and the absorption performance of toxic gas for terror were examined toward the PAN-ACF with the highest surface area. In the test results the surface area increased with increase of the activation temperature, but decreased with increase of the carbonization temperature. After carbonization condition ($900^{\circ}C$-15min) and activation condition ($900^{\circ}C$-30 min), we got the ACF with the highest surface area of $1204m^2/g$. In the absorption test of iodine and toxic gas for terror, this ACF showed more excellent absorption performance than the existing carbon-based adsorbent. Also, in order to give the function characteristic for a selective absorption, the stable nanoparticles of the Ag, Pt, Cu, Pd were prepared and impregnated on the PAN-based ACF in replacement of the existing method supporting metal catalysis. And were analyzed the surface characteristics and the $SO_{2}$ adsorption characteristics. In the $SO_{2}$ absorption performance test of the PAN-ACF with the impregnated nanoparticles, it wasn't change breakthrough time of Ag, Pt, Cu nanoparticle supported the PAN-ACF comparing with breakthrough time (326 sec) of the non supported PAN-ACF but Pd nanoparticle supported the PAN-ACF achieved excellent $SO_{2}$ absorption performance which has break-through time 925 sec.

• YAKHAK HOEJI
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• v.55 no.2
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• pp.106-115
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• 2011

Systematic toxicological analysis (STA) means the process for general unknown screening of drugs and toxic compounds in biological fluids. In order to establish STA, in previous study we investigated pattern of drugs & poisons in autopsy cases during 2007~2009 in Korea, and finally selected 62 drugs as target drugs for STA. In this study, rapid and simple drug identification and quantitative analytical program by gas chromatography-mass spectrometry(GC-MS) was developed. The in-house program, "DrugMan", consisted of modified chemstation data analysis menu and newly developed macro modules. Total 55 drugs among 62 target drugs were applied to this program, they were 14 antidepressants, 8 anti-histamines, 5 sedatives/hypnotics, 5 narcotic analgesics, 3 antipsychotic drugs, and etc. For calibration curves, fifty five drugs were divided into four groups of range considering their therapeutic or toxic concentrations in blood specimen, i.e. 0.05~1 mg/l, 0.1~1 mg/l, 0.1~5 mg/l or 0.5~10 mg/l. Standards spiked bloods were extracted by solid-phase extraction (SPE) with trimipramine-D3 as internal standard. Parameters such as retention times, 3 mass fragment ions, and calibration curves for each drug were registered to DrugMan. A series of identification, semi quantitation of target drugs and reporting the results were performed automatically. Calibration curves for most drugs were linear with correlation coefficients exceeding 0.98. Sensitivity rate of DrugMan was 0.90 (90%) for 55 drugs at the level of 0.5 mg/l. For standard spiked bloods at the level of 0.5 mg/l for 29 drugs, semi quantitative concentrations were ranged 0.36~0.64 mg/l by DrugMan. If more drugs are registered to database in DrugMan in further study, it will be useful tools for STA in forensic toxicology.

• Environmental Analysis Health and Toxicology
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• v.17 no.3
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• pp.197-205
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• 2002

Volatile organic compounds (VOCs) are an important public health problem throughout the world. Many important questions remain to be addressed in assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in the analytical determination of VOCs. Personal exposure measurements are needed to evaluate the relationship between microenvironmental concentrations and actual exposures. It is also important to investigate exposure frequency, duration, and intensity, as well as personal exposure characteristics. In addition to air monitoring, biological monitoring may contribute significantly to risk assessment by allowing estimation of absorbed doses, rather than just the external exposure concentrations, which are evaluated by environmental and personal monitoring. This study was conducted to establish the analytic procedure of VOCs in air, blood, urine and exhaled breath and to evaluate the relationships among these environmental media. The subjects of this study were selected because they are occupationally exposed to high levels of VOCs. Environmental, personal, blood, urine and exhalation samples were collected. Purge ＆ trap, thermal desorber, gas chromatography and mass selective detector were used to analyze the collected samples. Analytical procedures were validated with the“break through test”, 'quot;recovery test for storage and transportation”,“method detection limit test”and“inter-laboratory QA/QC study”. Assessment of halogenated compounds indicted that they were significantly correlated to each other (p value < 0.01). In a similar manner, aromatic compounds were also correlated, except in urine sample. Linear regression was used to evaluate the relationships between personal exposures and environmental concentrations. These relationships for aromatic and halogenated are as follows: Halogen $s_{personal}$ = 3.875+0.068Halogen $s_{environmet}$, ($R^2$= .930) Aromatic $s_{personal}$ = 34217.757-31.266Aromatic $s_{environmet}$, ($R^2$= .821) Multiple regression was used to evaluate the relationship between exposures and various exposure deter-minants including, gender, duration of employment, and smoking history. The results of the regression model-ins for halogens in blood and aromatics in urine are as follows: Halogen $s_{blood}$ = 8.181+0.246Halogen $s_{personal}$+3.975Gender ($R^2$= .925), Aromatic $s_{urine}$ = 249.565+0.135Aromatic $s_{personal}$ -5.651 D.S ($R^2$ = .735), In conclusion, we have established analytic procedures for VOC measurement in biological and environmental samples and have presented data demonstrating relationships between VOCs levels in biological media and environmental samples. Abbreviation GC/MS, Gas Chromatography/Mass Spectrometer; VOCs, Volatile Organic Compounds; OVM, Organic Vapor Monitor; TO, Toxic Organicsapor Monitor; TO, Toxic Organics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.160-166
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• 2018

The worldwide semi-conductor market has been growing for a long time. Manufacturing lines of semi-conductors need to handle several types of toxic gases. In particular, they need to be controlled accurately in real time. This type of toxic gas control system consists of many different kinds of parts, e.g., fittings, valves, tubes, filters, and regulators. These parts obviously need to be manufactured precisely and be corrosion resistant because they have to control high pressure gases for long periods without any leakage. For this, surface machining and hardening technologies of the metal block and metal gasket need to be studied. This type of study depends on various factors, such as geometric shapes, part materials, surface hardening method, and gas pressures. This paper presents strong concerns on a series of simulation processes regarding the differences between the inlet and outlet pressures considering several different fluid velocity, tube diameters, and V-angles. Indeed, this study will very helpful to determine the important design factors as well as precisely manufacture these parts. The EP (Electrolytic Polishing) process was used to obtain cleaner surfaces, and hardness tests were carried out after the EP process.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.639-654
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• 2016

This study building materials by relates to human hazard assessment in accordance with the combustion gas SEM, the flame-retardant foam FTIR and cone calorimeter to configure the Forest products of MDF and preservative treated Lauan two kinds of Retardant styrofoam, Styrofoam, Urethane foam and gypsum board four kinds of plastics material by the combustion gas were each analyzed. MDF was burned to the structure of the wood and the glue evenly mixed combustion area preservative treated Lauan, kept constant even in the form of high heat to penetrate deep into the wood flame retardant agents. Retardant styrofoam is due to feed my Dropped dissolved inorganic flame retardant without the fire-stick and confirmed that the weak form of gypsum board, but keep the column. In MDF ammonia ($NH_3$), lethal concentration (750 ppm) compared to 795 ppm, preservative treated Lauan is carbon dioxide ($CO_2$) that was greater than 2.5 times the lethal concentration (100,000 ppm) to 256,965 ppm, the lethal concentration (500 ppm) of hydrogen chloride (HCl). The Urethane greater than 697 ppm, 434 ppm also greatly exceeding the nitrogen dioxide ($NO_2$) lethal concentration (250 ppm) in Retardant styrofoam and 398 ppm was released. It is confirmed that the human body is extremely harmful gas emitted from most of the materials to be utilized as basic data for evaluating the hazard-specific human future building material.

• Fire Science and Engineering
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• v.29 no.4
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• pp.49-56
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• 2015

Toxic gases from five types of interior building materials were investigated according to Naval Engineering Standard (NES) 713. The materials were plywood, indoor wall coverings (wood wall plate members and pine wood), reinforced Styrofoam insulation, laminate flooring, and PVC. Specimens were measured using an NES 713 toxicity test apparatus to analyze the hazardous substances in combustion gas from the materials. We used the US Department of Defense standard (MIL-DTL, Military Standard) to calculate the toxicity index of the combustion gas. Emissions of $CO_2$ from all specimens did not exceed the NES 713 limit of 100,000 ppm. The amount of CO gas emissions from reinforced Styrofoam insulation was 6,098 ppm. 25 ppm and 49 ppm of formaldehyde were released from the reinforced Styrofoam insulation and PVC flooring, respectively. These values were less than the limit of 400 ppm. The highest emissions were from $NO_X$ emitted by plywood and were above the limit of 250 ppm. The toxicity index of the specimens were calculated as 5.19 for plywood, 4.13 for PVC flooring, 2.35 for reinforced Styrofoam insulation, 2.34 for laminate flooring, and 1.22 for indoor wall coverings (pine wood). Our research helps us to understand the properties of these five interior materials by analyzing the combustion gas and explaining the toxicity of constituents and the toxicity index. Also, it would be useful for giving fundamentals to guide the safe use of interior materials for applications.