• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.418-422
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• 2022

α-pinene is a natural volatile organic compound secreted by coniferous trees to protect themselves from attacks by insects, microorganisms, and viruses. Recently, studies have reported that α-pinene possesses pharmacological effects on various biological reactions such as anxiolytic, sleep-enhancing, anti-nociceptive, and inflammatory activity. Thus, forest bathing has recently received great attention as a novel therapy for treating severe diseases as well as psychological issues. However, appropriate places and timings for effective therapies are still veiled, because on-site monitoring of α-pinene gas in forests is barely possible. Although portable chemosensors could allow real-time analysis of α-pinene gas in forests, the α-pinene sensing properties of chemosensors have never been reported thus far. Herein, we report for the first time, the α-pinene sensing properties of an oxide semiconductor gas sensor based on rhombohedral In₂O₃ (h-In₂O₃) nanoparticles prepared by a microwave-assisted hydrothermal reaction. The h-In₂O₃ nanoparticle sensor showed a high response to α-pinene gas at ppm levels, even under humid conditions (for example, relative humidity of 50 %). The purpose of this research is to identify the potential of oxide semiconductor gas sensors for implementing portable devices that can detect α-pinene gas in forests in real-time.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.1
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• pp.9-17
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• 2022

As the COVID-19 pandemic situation worsens, the time spent indoors increases, and the exposure to indoor environmental pollution such as indoor air pollution and noise also increases, causing problems such as deterioration of human health, stress, and discord between neighbors. This paper designs and implements a system that measures and monitors indoor air quality and noise, which are representative evaluation criteria of the indoor environment. The system proposed in this paper consists of a particulate matter measurement subsystem that measures and corrects the concentration of particulate matters to monitor indoor air quality, and a noise measurement subsystem that detects changes in sound and converts it to a sound pressure level. The concentration of indoor particulate matters is measured using a laser-based light scattering method, and an error caused by temperature and humidity is compensated in this paper. For indoor noise measurement, the voltage measured through a microphone is basically measured, Fourier transform is performed to classify it by frequency, and then A-weighting is performed to correct loudness equality. Then, the RMS value is obtained, high-frequency noise is removed by performing time-weighting, and then SPL is obtained. Finally, the equivalent noise level for 1 minute and 5 minutes are calculated to show the indoor noise level. In order to classify noise into direct impact sound and air transmission noise, a piezo vibration sensors is mounted to determine the presence or absence of direct impact transmitted through the wall. For performance evaluation, the error of particulate matter measurement is analyzed through TSI's AM510 instrument. and compare the noise error with CEM's noise measurement system.

• Journal of Animal Science and Technology
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• v.64 no.2
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• pp.343-352
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• 2022

Pig slaughterhouses harbor high humidity because of the necessary cleaning that takes place simultaneously with slaughter, which facilitates the existence of mold. Due to the enclosed space, there are several limitations to the control of mold growth with respect to cleaning, ventilation, and drying. In this study, the prevalence of fungi was investigated in four pig slaughterhouses in Korea. Four fungi (Aspergillus niger, Penicillium commune, Penicillium oxalicum, and Cladosporium cladosporioides) were detected with the highest frequency. These four strains were subjected to various treatments to reduce their growth. The fungi were inoculated onto stainless steel (SS) chips and treated with ultraviolet (UV)-C irradiation and hot water. Individual treatments with UV-C (15, 30, 90, 150, 300, and 600 mJ/cm²), and hot water (60, 65, 70, and 83℃) were performed to sanitize the SS chips. Simultaneous cleaning with 60℃ hot water and more than 150 mJ/cm² of UV-C reduced the fungal incidence by > 6.5 Log from 6.6-7.0 Log CFU/cm² (initial count). Our results demonstrate that a combined treatment of UV-C and hot water is the most economical and convenient way to prevent microbiological contamination of small tools (such as knives and sharpeners) and steel surfaces in slaughterhouses.

• Analytical Science and Technology
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• v.36 no.4
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• pp.170-179
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• 2023

Starvation, diabetes, alcoholism and hypothermia cause ketoacidosis in the human body; therefore, the cause of death can be determined by analyzing ketone bodies in the blood of the deceased. In the case of decomposition of the cadaver, however, since collecting intact blood is impossible, ketone body analysis is performed using the spleen. However, the index for diagnosing ketoacidosis is based on blood concentration, and its correlation with ketone bodies present in the spleen remains unknown. In particular, since decomposition proceeds rapidly during summer, when temperature and humidity are high, understanding the correlation between ketone bodies in the blood and spleen is important to estimate the state at the time of death from a decaying body. Therefore, in the present study, the correlation between ketone bodies in the blood and spleen of the deceased was explored. Ketone bodies (beta-hydroxybutyric acid [BHB] and acetone) in the blood and spleen were analyzed and compared from autopsies (>100 mg·L^-1 BHB, blood basis) conducted at the Daejeon Forensic Research Institute from June to December 2021. Moreover, the concentration of ketone bodies in the spleen juice and tissues was compared assuming the scenario of extreme decomposition. Ketone retention concentration in the blood and spleen was positively correlated, and the ratio of BHB concentration in the spleen to BHB concentration in the blood ranged from 0.52 to 1.08 (mean = 0.85 ± 0.12), although the ratio may vary depending on the degree of decomposition of the corpse.

• Journal of Korean Association for Spatial Structures
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• v.23 no.2
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• pp.19-28
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• 2023

Timber structures are susceptible to moisture, contamination, and pest infestation, which can compromise their integrity and pose a significant fire hazard. Despite these drawbacks, timber's lightweight properties, eco-friendliness, and alignment with current architectural trends emphasizing sustainability make it an attractive option for construction. Moreover, timber structures offer economic benefits and provide a natural aesthetic that regulates building temperature and humidity. In recent years, timber domes have gained popularity due to their high recyclability, lightness, and improved fire resistance. Researchers are exploring hybrid timber and steel domes to enhance stability and rigidity. However, shallow dome structures still face challenges related to structural instability. This study investigates stability problems associated with timber domes, the behavior of timber and steel hybrid domes, and the impact of timber member positioning on dome stability and critical load levels. The paper analyzes unstable buckling in single-layer lattice domes using an incremental analysis method. The critical buckling load of the domes is examined based on the arrangement of timber members in the inclined and horizontal directions. The analysis shows that nodal snapping is observed in the case of a concentrated load, whereas snap-back is also observed in the case of a uniform load. Furthermore, the use of inclined timber and horizontal steel members in the lattice dome design provides adequate stability.

• Journal of The Korea Institute of Healthcare Architecture
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• v.30 no.3
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• pp.67-74
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• 2024

Purpose: The identification and quantification of indoor airborne contaminants, including bio-aerosols, particulates, and gaseous contaminants, are crucial for maintaining acceptable indoor air quality for hospital operating rooms (ORs). Laparoscopic surgery has become widely accepted for various surgical procedures due to its rapid recovery rate and the low risk associated with small incisions compared to conventional open surgery. The objective of this study is to investigate the indoor air quality in hospital ORs and to identify indoor airborne contaminants generated during laparoscopic surgery. Methods: Measurements of an indoor environment, including temperature, humidity and air quality, were performed in an OR before and during a laparoscopic surgery. Indoor airborne contaminants, including volatile organic compounds (VOCs), formaldehyde, carbon monoxide (CO), carbon dioxide (CO₂), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), suspended indoor particles, and airborne bacteria, were measured simultaneously. Results: The study determined that the concentrations of indoor air particles and airborne bacteria increased during the surgery but were within acceptable levels. However, the concentration of CO₂, reached a high level of 1,791 ppm due to the CO₂ gas required for maintaining the pneumoperitoneum during the surgery. Implications: The results emphasized the use of ventilation and filtration in a laparoscopic surgery room to lower the concentration of filterable and non-filterable contaminants.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.389-396
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• 2014

Purpose: The study examined dry eye symptoms of occupants in a newly constructed building and its effects on their work productivity and general activity. Methods: The study subjects were 33 office workers who spent more than eight hours per day on average in a new building constructed in the past three months. The indoor air quality of the new building was evaluated by measuring aldehydes, temperature and humidity. The level of dry eye symptoms was classified into normal, mild, moderate and severe by using the Ocular Surface Disease Index (OSDI). The experience of LASIK surgery, use of eye makeup, daily use time of a computer and smart-phone, and average daily working hours were also examined. The Work Limitation Productivity Questionnaire was used as the questionnaire about work productivity and general activity to measure the impairment level on a ten-point scale. Results: The concentration variation of formaldehyde in the office was $42.42{\pm}6.30{\mu}g/m^3$. The temperature and humidity were $26.2{\pm}0.70^{\circ}C$ and $40{\pm}1%$, respectively. The respondents with normal, mild, moderate and severe dry eye symptoms were 15.2%, 18.2%, 18.2% and 48.5%, respectively. The severity of dry eye symptoms and impairment of work productivity and general activity demonstrated high correlations of 0.599 and 0.655, respectively (p<0.001). Compared to the normal case, severe dry eye symptoms demonstrated significantly high impairment of work productivity and interruption of general activity (p<0.001). The case of serious dry symptoms showed the possibilities of having impairment level of work productivity and interruption of general activity above three points 3.26 times (p=0.032) and 2.25 times (p=0.045), respectively, higher than that of the normal case. Conclusions: It was confirmed that dry eye symptoms among office workers in a newly constructed building affects work productivity and general activity.

• Journal of Korean Society of Forest Science
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• v.40 no.1
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• pp.25-34
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• 1978

Trial and demonslative reforestations were planted by Korea German Management Project at Ulju district in 1976. The follow results that were investigated at spring time in 1977 showed the different situation of winter damage according to site condition and species. 1. Picea abies was completely dried out in this district and its reason was to be thought as a winter damage by cold-dry wind. 2. Cryptomeria japonica was seriously damaged in comparing with Chamaecyparis obtusa and very seriously damaged on the wind-exposured site. So these species are also unsuitable species like Picea abies in this district. 3. The resistance ranking to winter dry wind damage were Picea, Cryptomeria, Chamaecyparis, ${\times}$ Pinus rigitaeda. Pinus rigida, Larix leptolepis and Alnus hirsuta. The falling leave species like larch in this district during winter were thought in necessary to select as the planting species for almost very little winter damage. 4. ${\times}$ Pinus rigitaeda to be showed as a suitable species in this district were also seriously damaged on exposured site and, Pinus rigida and Larix were also attacked with small damage. The potassium-phosphorus fertilizer dressing plots had a trend to reduce this winter damage until some level. 5. The winter climate can be devided into 10 zone in order to evaluate the right or wrong of suitable on the exotic species. The Yongnam region in eastern side of Sobaik mountain are far drier than the Honam region in western side of Sobaik mountain during winter time. Picea abies, Cryptomeria and Chamaecyparis originated in the high humidity winter climate are to be thought to be more suitable in the Honam region than the Yongnam region. Specially the suitable site of Picea abies should be only found in the region with high humidity and much precipitation except the Yongnam region.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.1
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• pp.38-55
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• 2018

Hourly measurements of $PM_{2.5}$ mass, organic and elemental carbon (OC and EC), and water-soluble ionic species were made at the air quality intensive monitoring stations in Baengryeongdo (BR) and Seoul (SL) during the winter (December 01~31, 2013) and summer (July 10~23, 2014) periods, to investigate the increase of $PM_{2.5}$ and secondary ionic species and the reasons leading to their increase during the two seasons. During winter, $PM_{2.5}$ and its major chemical species concentrations were higher at SL than at BR. Contribution of organic mass to $PM_{2.5}$ was approximately 1.7 times higher at BR than at SL, but the $NO_3{^-}$ contribution was two times higher at SL. Total concentration of secondary ionic species ($SO{_4}^{2-}$, $NO_3{^-}$, and $NH_4{^+}$) at BR and SL sites accounted for 29.1 and 40.1% of $PM_{2.5}$, respectively. However, during summer, no significant difference in chemical composition of $PM_{2.5}$ was found between the two sites with the exception of $SO{_4}^{2-}$. Total concentration of the secondary ionic species constituted on average 43.9% of $PM_{2.5}$ at BR and 53.0% at SL. A noticeable difference in chemical composition between the two sites during summer was attributed to $SO{_4}^{2-}$, with approximately twofold concentration and 10% higher contribution in SL. Low wind speed and high relative humidity were important factors in secondary formation of water-soluble ionic species during winter at SL, resulting in $PM_{2.5}$ increase. While the secondary formation during summer was attributed to strong photochemical processes in daytime and high relative humidity in nighttime hours. The increase of $PM_{2.5}$ and its secondary ionic species during the winter haze pollution period at SL was mainly caused either by long-range transport (LTP) from the eastern Chinese regions, or by local pollution. However, the increased $SO{_4}^{2-}$ and $NO_3{^-}$ during summer at SL were mainly caused by LTP, photochemical processes in daytime hours, and heterogeneous processes in nighttime hours.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.238-249
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• 2019

The evapotranspiration is estimated based on weather factors such as temperature, wind speed and humidity, and the Hargreaves equation is a simple equation for calculating evapotranspiration using temperature data. However, the Hargreaves equation tends to be underestimated in areas with wind speeds above 3 m s^-1 and overestimated in areas with high relative humidity. The study was conducted to determine Hargreaves equation coefficient in 82 regions in Korea by comparing evapotranspiration determined by modified Hargreaves equation and the Penman-Monteith equation for the time period of 2008~2018. The modified Hargreaves coefficients for 50 inland areas were estimated to be 0.00173~0.00232(average 0.00196), which is similar to or lower than the default value 0.0023. On the other hand, there are 32 coastal areas, and the modified coefficients ranged from 0.00185 to 0.00303(average 0.00234). The east coastal area was estimated to be similar to or higher than the default value, while the west and south coastal areas showed large deviations by area. As results of estimating the evapotranspiration by the modified Hargreaves coefficient, root mean square error(RMSE) is reduced from 0.634~1.394(average 0.857) to 0.466~1.328(average 0.701), and Nash-Sutcliffe Coefficient(NSC) increased from -0.159~0.837(average 0.647) to -0.053~0.910(average 0.755) compared with original Hargreaves equation. Therefore, we confirmed that the Hargreaves equation can be overestimated or underestimated compared to the Penman-Monteith equation, and expected that it will be able to calculate the high accuracy evapotranspiration using the modified Hargreaves equation. This study will contribute to water resources planning, irrigation schedule, and environmental management.