• Journal of Soil and Groundwater Environment
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• v.22 no.6
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• pp.112-119
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• 2017

In this study, the availability of cow manure as raw material for solid fuel production was investigated. Since the water content of the cow manure was too high, it was dewatered using a laboratory hydraulic compressure ($11.3kg/cm^2$). The moisture content of the cow manure decreased from 82.01% to 73.36 wt.%. The dewatered cow manure was homogenized by the experimental apparatus and then put into the rotating cylindrical apparatus. From the consecutive processes, the cow ball-shaped pellet which size ranged from 3.0 to 25.0 mm was produced. The major factor for making palletized fuel from cow manure was the moisture content. Based on the experimental data, the moisture content of cow manure for pelletizing cow manure was identified as 65~75 wt.%. When the moisture content of the cow manure was lower than 30 wt.%, the diameter of the pellets maded from cow manure was smaller than 3 mm. On the other hand, when the water content of the cow manure was higher than 75 wt/%, the diameter of the processed pellets tended to be larger than 25 mm. The characteristics of the processed cow manure pellets was analyzed to be in accordance with the livestock solid fuel quality standard. The pyrolysis characteristic of the pellet was analyzed by raising the heating temperature of the experimental equipment from 200 to $900^{\circ}C$. The mass change between of 20 and $130^{\circ}C$ corresponds to the amount of moisture contained in the cow manure. The amount of moisture was about 15% of the total weight of cow manure samples. The cow manure pellet was thermally stable up to $280^{\circ}C$. It can be interpreted that combustion of cow manure pellet does not occur until the surface temperature reaches $280^{\circ}C$. The mass change of pellet between of 280 and $450^{\circ}C$ was considered to be due to the vaporization of volatile organic compounds (VOCs) present in the cow manure pellet. The maximum production of VOCs was showed near $330^{\circ}C$.

• Korean Journal of Weed Science
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• v.31 no.1
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• pp.96-102
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• 2011

The objective of this study was to find herbicidal compounds in the essential oil of palmarosa (Cymbopogon martini). Of essential oils from basil (Ocimum basilicum), blackpepper (Piper nigrum), clary sage (Salvia sclarea), ginger (Zingiber pfficinale), hyssop (Hyssopus officinalis), nutmag (Myristica fragrance), palmarosa (Cymbopogon martini), fennel (Foeniculum vulgare), sage (Salvia leucantha), and spearmint (Mentha spicta), the herbicidal activity of palmarosa essential oil, which was determined by a seed bioassay using rapeseed (Brassica napus L.), was highest ($GR_{50}$ value, $201{\mu}g\;mL^{-1}$). In palmarosa essential oil, 11 volatile organic chemicals were identified by gas chromatography-mass spectometry with solid-phase micro-extraction apparatus and the major constituents were geraniol (40.23%), geraniol acetate (15.57%), cis-ocimene (10.79%), and beta-caryophyllene (8.72%). The $GR_{50}$ values of geraniol, citral, nerol, and geranyl acetate were 151, 224, 452, and $1,214{\mu}g\;mL^{-1}$, respectively. In greenhouse and field experiments, foliar application of palmarosa essential oil at the level of $80kg\;ha^{-1}$ controlled weeds effectively. Overall results of this study showed that the herbicidal activity of palmarosa essential oil could be due to geraniol and citral which had lower $GR_{50}$ values.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.3
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• pp.200-208
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• 2012

Objectives: This study investigated the performance of three separate units of a portable photoionization detector (PID, ppb-RAE 3000) for measuring volatile organic compounds (VOCs) in a laboratory. Methods: A laboratory evaluation of the accuracy, precision, and inter-instrumental variance of three separate units of a portable PID (ppb-RAE 3000) was performed. The evaluation was based on the preparation of a test air sample of known toluene or ethylacetate concentration in a Tedlar$^{(R)}$ bag. The test air sample was monitored and data were logged consecutively by the three PIDs. A certified gas of 50 ppm toluene was also monitored during the test to ensure the reliability of the generated test air sample. Four different concentrations ranging from 0.1 to 2 TLV were used and a series of five measurements for each concentration level was performed. The accuracy was evaluated using National Institute for Occupational Safety and Health (NIOSH) criteria. Results: The results from the oldest ppb-RAE3000 unit among the three test units generally fell outside the NIOSH recommended accuracy criteria of ${\pm}25%$, whereas the other two units produced results which were acceptable at, or greater than, 25 ppm of toluene, or 0.5 TLV. These units also met the NIOSH criteria for some ethylacetate measurements but the results were not consistent. Conclusions: Considering the inconsistent performance of these ppb-RAE 3000 units, this device may not be appropriate for use as an alternative to the standard measurement methods. However, it can serve good survey instruments to identify exposure sources or concentration profiles. For all applications, the ppb-RAE 3000 should be used with frequent calibration checks, additional validation using a reference material, and careful maintenance.

• Polymer(Korea)
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• v.36 no.1
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• pp.47-52
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• 2012

Abstract: In this study, PAN/$TiO_2$ fiber mats were fabricated from polyacrylonitrile (PAN) and titanium(IV) butoxide ($Ti(OBu)_4$) by an electrospinning method with various solution concentrations, applied voltages and solution flow rates. The fiber mats were irradiated with an electron beam to induce structural crosslinking and enhance photocatalytic activity. As a result, uniform and bead-free fibers without pits or cracks on surface were obtained at 5 wt% of $Ti(OBu)_4$ solution with 15 kV and 0.02 mL/min flow rate. The PAN/$TiO_2$ fiber mats were irradiated with an electron beam of 1.14 MeV acceleration voltage, 4 mA of current and $1{\times}10^4kGy$. Electron beam irradiation was enhanced the photocatalytic activity of PAN/$TiO_2$ nano fiber mat. The photocatalytic activity of the PAN/$TiO_2$ fiber mat was analyzed by degradation of methylene blue and volatile organic compounds.

• Journal of Environmental Health Sciences
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• v.47 no.5
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• pp.398-409
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• 2021

Background: The types and effects of hazardous pollutants in indoor air may vary depending on the characteristics of the sources and pollutants caused by physical and chemical properties of buildings, the influence of outdoor air, and the exposure and use characteristics of residents. Objectives: This study was conducted to provide basic data on the establish of indoor air quality management for different classes of public-use facilities by presenting the characteristics of concentration distribution of hazardous pollutants by different public-use facilities and the status of the excess proportion of exceeding standards. Methods: This study analyzed self-measurement data from public-use facilities taken from 2017 to 2019 A total of 133,525 facilities were surveyed. A total of 10 types of pollutants that have maintenance and recommended standards stipulated in the Indoor Air Quality Control Act from the Ministry of Environment were investigated. The excess proportion and the substances exceeding the criteria for each type of public-use facilities for these pollutants were investigated. Results: As a result of the analysis of the proportion of exceeding the standard for each type of public-use facility, the facilities with the highest excess proportion of the standards for each hazardous pollutant were: PM₁₀ in railway stations (8.93%), PM_2.5 in daycare centers (7.36%), CO₂ in bus terminals (2.37%), HCHO in postpartum care centers (4.11%), total airborne bacteria in daycare centers (0.69%), CO in museums (0.1%), NO₂ in postpartum care centers (1.15%), Rn in museums (0.78%), total volatile organic compounds in postpartum care centers (7.20%) and mold in daycare centers (1.44%). Conclusions: Although uncertainty may arise because this study is a result of self-measurement, it is considered that this study has significance for providing basic data on the establishment in the future of indoor air quality management measures customized for each type of public-use facility.

• Journal of Environmental Health Sciences
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• v.47 no.2
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• pp.131-143
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• 2021

Objectives: This study aims to investigate the atmospheric concentration of polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) and the urinary concentration of biomarkers in residents near the Shinpyeong·Jangrim Industrial Complex to compare them with those of residents in a control area. Methods: Hazardous air pollutants (PAHs and VOCs) were measured in an exposure area (two sites) and a control area (one site). Urine samples were collected from residents near the industrial complex (184 persons) and residents in the control area (181 persons). Multiple linear regression analysis was used to identify which factors affected the concentration of PAHs and VOCs metabolites. Results: The average atmospheric concentration of PAHs in Shinpyeong-dong and Jangrim-dong was 0.45 and 0.59 ppb for pyrene, 0.15 and 0.16 ppb for benzo[a]pyrene, and 0.29 and 0.35 ppb for dibenz[a,h]anthracene. The average atmospheric concentration of VOCs was 1.10 and 0.99 ppb for benzene, 8.22 and 11.30 ppb for toluene, and 1.91 and 3.05 ppb for ethylbenzene, respectively. The concentrations of PAHs and VOCs in residents near the Shinpyeong·Jangrim Industrial Complex were higher than those of residents in the control area. Geometric means of urinary 2-hydroxyfluorene, 1-hydroxypyrene, methylhippuric acid, and mandelic acid concentrations were 0.45, 0.22, 391.51, and 201.36 ㎍/g creatinine, respectively. Those levels were all significantly higher than those in the control area (p<0.05). In addition, as a result of multiple regression analysis, even after adjusting for potential confounding factors such as gender and smoking, the concentration of metabolites in urine was high in residents near the Shinpyeong·Jangrim Industrial Complex. Conclusion: The results of this study show the possibility of human exposure to VOCs in residents near the Shinpyeong·Jangrim Industrial Complex. Therefore, continuous monitoring of the local community is required for the management of environmental pollutant emissions.

• Clean Technology
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• v.24 no.4
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• pp.280-286
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• 2018

In this study, the adsorption performance of vapor phase VOCs under dry conditions was evaluated by using two metal oxides, $TiO_2$ powder and $Al_2O_3$ powder. BET analysis and ammonia in-situ FT-IR analysis were used to analyze specific surface area and surface acid site. As a result, $TiO_2$ powder and $Al_2O_3$ powder had a specific surface area of $317.6m^2\;g^{-1}$ and $64m^2\;g^{-1}$, respectively. In the case of $TiO_2$ powder, many acid sites were observed on the surface. As a result of evaluating the vapor phase VOCs adsorption performance using two metal oxide powders, $TiO_2$ powder having a relatively large specific surface area and a large number of acid sites exhibited relatively good adsorption performance. In particular, it is considered that the specific surface area directly affects the adsorption performance, and further study on the effect of the acid site is required. Based on the $TiO_2$ exhibited excellent adsorption performance, it manufactured into various forms of honeycomb, hollow fiber and disc. As a result, the adsorption performance was lower than that of the powder, but it is advantageous in view of applicability. In addition, it was confirmed that the disc adsorbent having excellent thermal durability due to the characteristics of the manufacturing process stably maintains adsorption performance even at a high temperature desorption process several times.

• Fire Science and Engineering
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• v.32 no.6
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• pp.84-90
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• 2018

Chemical accidents occur in various forms, such as explosions, leaks, spills, and fires. In particular, chemical accidents caused by fires seriously affect the surrounding air environment due to soot, causing anxiety to the residents. Therefore, it is important to identify the causative substances quickly and examine the influence of air quality in the surrounding area. In this paper, proton transfer reaction-time of flight mass spectrometry(PTR-ToFMS) was used to identify the causative material in a fire and monitor the air quality in real time. This analyzer is capable of real-time analysis with a rapid response time without sample collection and pretreatment. In addition, it is suitable for quantitative and qualitative analysis of most volatile organic compounds with high hydrogen affinity, to identify the cause of fire and examine the influence of ambient air. In April 2018, when a local fire occurred, methanol, acetone, and methyl ethyl ketone were the main causative agents in PTR-ToFMS.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.152-158
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• 2019

Measure the type and content of VOCs for A-company epoxy coating and B-company floor coating(Type A, B), which are used as flooring materials for parking lots. Than the VOCs used gas detectors to measure gas emissions, assuming the worst environment to reduce errors in external environments in the formaldehyde, toluene and xylene harmful to workers and tenants. As a result, A-company epoxy coating has the largest amount of VOCs, and compared to A-company epoxy coating, B-company floor coating of A type represented about 79% less and B type about 96% less. In addition, A-company epoxy coating was also the highest in gas emission measurement for formaldehyde, toluene and xylene using gas detector after 1 hour and 8 hours in closed environment conditions. B-company floor coating A type was less than A-company epoxy coating, which was about 42.3% less measured. And type B satisfied all TWA even in closed environment conditions.

• Korean Journal of Heritage: History & Science
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• v.49 no.4
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• pp.114-125
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• 2016

Lacquer is one of the most widely used natural resin in East Asia since Neolithic Age. As a major ingredient of lacquerware, lacquer is waterproof, insect-proof and rot-proof to be durable and anti-abrasion, generally utilized for mainly painting purpose. According to lacquerware excavated from several sites of Japan and China, lacquerware seems to appear in Neolithic Age. On the other hand in case of excavation research in Korea, lacquerwares are found after the Bronze Age. The initial purpose of lacquer is estimated to be adhesive, regarding the literatures mentioning bitumen(Yeoksceong ), animal glue(Kyeo) and egg alumen(Nanbaek). Especially piece of jar coffin unearthed in Pyeongtaek Daechu-ri site had trace of restoration by lacquer and hemp as an evidence of lacquer for adhesion in Pre-Three Kingdoms period. Since then a trend to restore the broken ceramics with lacquer and decorate with golden foil lasted especially in Joseon Dynasty. In the field of gold plated lacquer method, mother-of-pearl inlaying technique for lacquerware and restoration of buildings, lacquer is still used as adhesive. Due to matter of reversibility lacquer is being avoided for conservation and restoration of cultural heritage. Lacquer as a traditional material for adhesive since ancient times, however, has advantage in adhesion strength and durability. Because synthetic resin adhesive has problem of emission of volatile organic compounds and aging over time, lacquer receives attention recently. On the contrary, by combination adhesive from mixing lacquer and animal glue, already proved the possibility of applicability and chemical modification. A research to utilize lacquer as modern paint or functional material is also conducted continuously also in China and Japan. To put traditional material into practical use and modernize, chemical research from the molecular level of the lacquer is necessary in the near future.