• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.1
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• pp.14-26
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• 2022

Recently, according to the severity of air pollution, interest in air pollution is increasing. The IoT based fine dust monitoring system proposed in this paper allows the measurement and monitoring of fine dust, volatile organic compounds, carbon dioxide, etc., which are the biggest causes affecting the human body among air environmental pollution. The proposed system consisted of a device that measures atmospheric environment information, a server system for storing and analyzing measured information, an integrated monitoring management system for administrators and smart phone applications for users to enable visualization analysis of atmospheric environment information in real time. In addition, the effectiveness of the proposed fine dust monitoring system based on the Internet of Things was verified by using the response speed of the system, the transmission speed of the sensor data, and the measurement error of the sensor. The fine dust monitoring system based on the Internet of Things proposed in this paper is expected to increase user convenience and efficiency of the system by visualizing the air pollution condition after measuring the air environment information with portable fine dust measuring device.

• Journal of Platform Technology
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• v.9 no.4
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• pp.79-89
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• 2021

In this paper, the fine dust (PM10) and ultrafine dust (PM2.5) measurement platforms are designed to be mobile and fixed using oneM2M, the international standard for IoT. The fine dust measurement platform is composed and designed with a fine dust measurement device, agent, oneM2M platform, oneM2M IPE, and monitoring system. The main difference between mobile and fixed is that the mobile uses the MQTT protocol for interconnection between devices and services without blind spots based on LTE connection, and the fixed uses the LoRaWAN protocol with low power and wide communication range. Not only fine dust, but also temperature, humidity, atmospheric pressure, volatile organic compounds (VOC), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and noise data related to daily life were collected. The collected sensor values were managed using the common API provided by oneM2M through the agent and oneM2M IPE, and it was designed into four resource types: AE and container. Six functions of operability, flexibility, convenience, safety, reusability, and scalability were analyzed through the fine dust measurement platform design.

• 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.

• Food Science of Animal Resources
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• v.43 no.3
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• pp.471-490
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• 2023

In this study, the duck eggs were salted with none or 2.5% and 5.0% (v/v) of liquid smoke (LS), respectively. As a control, samples salted without LS were used. The 2-thiobarbituric acid (TBA) values, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability, and reducing power of the three groups were tested at 0, 7, 14, and 21 and 28 days to determine the effects of LS on the antioxidant activity of treated eggs. In addition, gas chromatography-mass spectrometry (GC-MS) and electronic nose (E-Nose) were used to analyze the volatile flavor components of fresh duck eggs, LS, control, and salted duck eggs enriched with 2.5% (v/v) LS after 28 days of salting. The TBA value considerably increased with an increase in salting period, and the treated egg's TBA value significantly associated with LS concentration. The TBA value decreased as the LS concentration increased. The amount of LS present was highly associated with their capacity to scavenge DPPH radicals. The reducing power of the samples was substantially correlated with the LS concentration, and the reducing power increased with increasing LS concentration. The GC-MS data revealed that phenols and ketones were the predominant chemicals present in the LS, and they were also found in the eggs added to the LS even though they were absent in the fresh eggs and control. The flavor of the control group and treated eggs with LS differed significantly, according to the principal component analysis and radar map of the E-nose. The texture study results revealed that the LS significantly impacted the hardness, cohesiveness, and chewiness of eggs.

• Clean Technology
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• v.15 no.1
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• pp.1-8
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• 2009

The adoption of compressed natural gas (CNG) as a vehicle fuel is a common phenomenon as it is accelerating worldwide. Increasing number of CNG driven vehicles around the world has jumped up from one million in 1996 to five million in 2006. CNG as a vehicle fuel is very popular to the end users because of its clean-burning properties and cost effective solution compared to other alternative fuels like diesel and gasoline. The use of CNG as a fuel reduces vehicular emission that is consisted of carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen ($NO_x$), carbon dioxide ($CO_2$) etc. This research highlights the characteristics of CNG vehicles, CNG arrangement in the vehicles, CNG fueling procedures and most importantly the environmental and economic factors that are highly considered as cost effective solution for the flexibility of using CNG in the automobiles.

• Journal of Environmental Science International
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• v.32 no.5
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• pp.285-301
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• 2023

This study analyzed characteristics of ozone (O₃) formation regimes in Busan over a period of recent five years (2015~2019) and compared the findings with those obtained in Seoul. We employed four observed variations: early morning commuting-hour (i.e., 06:00-09:00 LST) nitrogen dioxide (NO₂), peak-hour (i.e., 12:00-16:00 LST) O₃, 8-hour average O₃ (MDA8 O₃), and △O₃ (=O_{3_max}- O_{3_min}) in Busan and Seoul. In addition, the NO₂-O₃ relation was assessed to interpret which of NOx-limited or volatile organic compound (VOC)-limited was dominant. In Busan, the annual mean O₃ concentration was relatively higher than in Seoul, whereas there were fewer high-concentration days. The Pearson correlation coefficients (R) between Early morning-hour NO₂ and the Peak-hour O₃ was positive (but close to zero) in Busan and negative in Seoul. Likewise, the R between the Early morning-hour NO₂ and the △O₃ showed a relatively considerable positive correlation (R=+0.4~0.5)(R=+0.4~0.5) in Busan, while a weak positive correlation (R=+0.1~0.2) in Seoul. From this result, it can be inferred that the O₃ formation regime in Busan was intrepreted to be nearly neutral or relatively closer to the NO_x-limited regime than Seoul, while Seoul to the VOC-limited regime. The study findings imply that O₃ control strategies should be applied differently in Busan and Seoul. The results here were inferred from surface NO₂ and O₃ observations, and the varification studies based on in-situ VOCs measurements would be needed.

• Journal of Environmental Science International
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• v.31 no.12
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• pp.1127-1134
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• 2022

Herein , the effect of changes in the organic loading rate in anaerobic digestion was evaluated. The experiment was carried out by a laboratory -scale semi-continuous stirred tank reactor, and feedstock was food-waste leached. The organic loading rate was increased by 0.5 kgVS/m3 in each phase from 1.0 kgVS/m3 to 4.0 kgVS/m3. At the end of the operation, to check the failure of the reactor, the organic loading rate was increased by 1.0 kgVS/m3 in each phase and reached 6.0 kgVS/m3. This shows that the biogas yield decreased as organic loading rate increased. Biogas production seemed to be unstable at 3.5-6.0 kgVS/m3. Moreover, biogas production dramatically fell to approximately 0 mL at 6.0 kgVS/m3, which was decided as the operation failure on the 16th day of the las tphase. The result of the reactor analysis shows that the cumulation of volatile fatty acid increased as the organic loading rate increased. This seems to occur due to the decreasein pH in the reactor and led to extinction of anaerobic bacteria, which were the biogas products. Although the buffer compound (alkalinity) could prevent the decline in pH, the concentration of alkalinity was found to be lacking at a high organic loading rate

• Animal Bioscience
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• v.36 no.5
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• pp.797-809
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• 2023

Objective: Many scientists have investigated solutions to reduce microbiological risks in dry-aged meat after the dry-aging technology was revived for high quality and value-added premium meat product in the market. This study aimed to investigate the effect of scoria powder in onggi (Korean earthenware) on the meat quality of pork loins during 21 days of dry aging and to elucidate its mechanism of action. Methods: The pork loins were randomly divided into three groups: aged in vacuum-packaging, onggi containing red clay only (OR), and onggi containing 30% red clay and 70% scoria powder (OS). Microbial analyses (total plate count and Lactobacillus spp.) and physicochemical analyses (pH, shear force, volatile basic nitrogen [VBN], water activity, 2-thiobarbituric acid reactive substances, water content, water holding capacity, cooking loss, and color analysis) of aged meat were conducted. Far-infrared ray emission, quantification of immobilized L. sakei and microstructure of onggi were investigated to understand the mechanism. Results: On day 21, the meat aged in OS exhibited lower pH, shear force, VBN, and water activity than those aged in OR, along with an increase in the number of Lactobacillus spp. OS had a smaller pore diameter than OR, implying lower gas permeability, which could promote the growth of L. sakei. Conclusion: OS improved the microbiological safety and storage stability of pork loin during dry aging by increasing number of Lactobacillus spp. possibly due to low permeability of OS.

• Food Science of Animal Resources
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• v.42 no.2
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• pp.332-340
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• 2022

The objective of this study was to determine the optimal cooking time by considering the cooking loss, shear force, and off-odor reduction of pork large intestines. Commercial pork large intestines were purchased, quartered perpendicularly, and cooked in boiling water for 40, 120, 180, and 240 min. Cooking loss of the samples increased after 240 min of cooking (10.92, p<0.05) while shear force value was lower at 240 min (4.45) compared to that at other cooking times (p<0.001). The amount of major volatile organic compounds showed a decreasing trend with increasing cooking time. In particular, the amount of methyl pentanoate (17,528.71) and methyl isobutyrate (812.51), compounds with a relatively low odor threshold, decreased significantly after 120 min of cooking and no change was observed thereafter (p<0.05). In addition, the amount of 2-pentanol (3,785.65) and 1-propanol (622.26), possibly produced by lipid oxidation, significantly decreased at the same cooking time (p<0.001). In the principal component analysis, only the 40 min cooking time was significantly different from other cooking time by high amounts of 1-propanol, 2-pentanol, and methyl isobutyrate. In conclusion, in the present study, the optimal cooking time for pork large intestines was 120 min in terms of off-odor reduction, cooking loss, and shear force.

• Analytical Science and Technology
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• v.22 no.1
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• pp.57-64
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• 2009

A material database has been developed for VOCs and formaldehyde emitted from building materials in this study. New classification system has been made by correlating the classification methods used in Korean Air Cleaning and Environmental Protection Agency. The developed databases include emission rates of TVOC, 5VOC and formaldehyde emitted from each building material. In addition, the databases can be used as an input variable to estimate indoor air quality (IAQ) using computer simulation since they also contain chemical component and general imformation. Box plot was used to do statistical analysis for emission rates of formaldehyde and TVOCs from different types of building materials. Also we confirmed the building materials worsening IAQ by categorizing the emission characteristic of different types of pollutants.