• Korean Journal of Heritage: History & Science
• /
• v.54 no.1
• /
• pp.206-219
• /
• 2021

The warming of the climate is increasing the damage caused by termites to wooden buildings, cultural properties and houses. A group removal system can be installed around the building to detect and remove termite damage; however, if the site is not visited regularly, every one to two months, you cannot observe whether termites have spread within, and it is difficult to take prompt effective action. In addition, since the system is installed and operated in an exposed state for a long period of time, it may be ineffective or damaged, resulting in a loss of function. Furthermore if the system is installed near a cultural site, it may affect the aesthetic environment of the site. In this study, we created a detection system that uses wood, cellulose, magnets, and magnetic sensors to determine whether termites have entered the area. The data was then transferred to a low power LoRa Network which displayed the results without the necessity of visiting the site. The wood was made in the shape of a pile, and holes were made from the top to the bottom to make it easier for termites to enter and produce a cellulose sample. The cellulose sample was made in a cylindrical shape with a magnet wrapped in cellulose and inserted into the top of a hole in the wood. Then, the upper part of the wood pile was covered with a stopper to prevent foreign matter from entering. It also served to block external factors such as light and rainfall, and to create an environment where termites could add cellulose samples. When the cellulose was added by the termites, a space was created around the magnet, causing the magnet to either fall or tilt. The magnetic sensor inside the stopper was fixed on the top of the cellulose sample and measured the change in the distance between the magnet and the sensor according to the movement of the magnet. In outdoor experiments, 11 cellulose samples were inserted into the wood detection system and the termite inflow was confirmed through the movement of the magnet without visiting the site within 5 to 17 days. When making further improvements to the function and operation of the system it in the future, it is possible to confirm that termites have invaded without visiting the site. Then it is also possible to reduce damage and fruiting due to product exposure, and which would improve the condition and appearance of cultural properties.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.1
• /
• pp.172-178
• /
• 2021

In the ship repair market, interest in maintenance and repair is steadily increasing due to the reinforcement of prevention of environmental pollution caused by ships and the reinforcement of safety standards for ship structures. By reflecting this effect, the number of requests for repairs by foreign shipping companies increases to repair shipbuilders in the Southwest Sea. However, because most of the repair shipbuilders in the southwestern area are small and medium-sized companies, it is difficult to lead to the integrated synergy effect of the repair shipbuilding companies. Moreover, the infrastructure is not integrated; hence, using the infrastructure jointly is a challenge, which acts as an obstacle to the activation of the repair shipbuilding industry. Floating docks are indispensable to operating the repair shipbuilding business; in addition, most of them are operated through renovation/repair after importing aging caisson docks from overseas. However, their service life is more than 30 years; additionally, there is no structure inspection standard. Therefore, it is vulnerable to the safety field. In this study, the finite element analysis program of ANSYS was used to evaluate the structural safety of the modified caisson dock and obtain additional structural reinforcement schemes to solve the derived problems. For the floating docks, there are classification regulations; however, concerning structural strength, the regulations are insufficient, and the applicability is inferior. These insufficient evaluation areas were supplemented through a detailed structural FE-analysis. The reinforcement plan was decided by reinforcing the pontoon deck and reinforcement of the side tank, considering the characteristics of the repair shipyard condition. The final plan was selected to reinforce the side wing tank through the structural analysis of the decision; in addition, the actual structure was fabricated to reflect the reinforcement plan. Our results can be used as reference data for improving the structural strength of similar facilities; we believe that the optimal solution can be found quickly if this method is used during renovation/repair.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.25 no.1
• /
• pp.21-28
• /
• 2021

Purpose Brown fat, or brown adipose tissue (BAT), is involved in non-shivering thermogenesis and creates heat through glucose metabolism. BAT activation occurs stochastically by internal factors such as age, sex, and body mass index (BMI) and external factors such as temperature and environment. In this study, as a retrospective, electronic medical record (EMR) observation study, statistical analysis is conducted to confirm BAT activation and various factors. Materials and Methods From January 2018 to December 2019, EMR of patients who underwent PET/CT scan at the National Cancer Center for two years were collected, a total of 9155 patients were extracted, and 13442 case data including duplicate scan were targeted. After performing a univariable logistic regression analysis to determine whether BAT activation is affected by the environment (outdoor temperature) and the patient's condition (BMI, cancer type, sex, and age), A multivariable regression model that affects BAT activation was finally analyzed by selecting univariable factors with P<0.1. Results BAT activation occurred in 93 cases (0.7%). According to the results of univariable logistic regression analysis, the likelihood of BAT activation was increased in patients under 50 years old (P<0.001), in females (P<0.001), in lower outdoor temperature below 14.5℃ (P<0.001), in lower BMI (P<0.001) and in patients who had a injection before 12:30 PM (P<0.001). It decreased in higher BMI (P<0.001) and in patients diagnosed with lung cancer (P<0.05) In multivariable results, BAT activation was significantly increased in patients under 50 years (P<0.001), in females (P<0.001) and in lower outdoor temperature below 14.5℃ (P<0.001). It was significantly decreased in higher BMI (P<0.05). Conclusion A retrospective study of factors affecting BAT activation in patients who underwent PET/CT scan for 2 years at the National Cancer Center was conducted. The results confirmed that BAT was significantly activated in normal-weight women under 50 years old who underwent PET/CT scan in weather with an outdoor temperature of less than 14.5℃. Based on this result, the patient applied to the factor can be identified in advance, and it is thought that it will help to reduce BAT activation through several studies in the future.

• Korean Journal of Mineralogy and Petrology
• /
• v.35 no.1
• /
• pp.65-73
• /
• 2022

The proper estimation of physical and chemical properties of Earth materials and their structures at high pressure and high temperature conditions is key to the full understanding of diverse geological processes in Earth and planetary interiors. Multi-anvil press - high-pressure generating device - provides unique information of Earth materials under compression, mainly relevant to Earth's upper mantle. The quantitative estimation of the relationship between the oil load within press and the actual pressure conditions within the sample needs to be established to infer the planetary processes. Such pressure-load calibration has often been based on the phase transitions of crystalline earth materials with known pressure conditions; however, unlike at high temperature conditions, phase transitions at low (or room) temperatures can be sluggish, making the calibration at such conditions challenging. In this study, we explored the changes in Al coordination environments of permanently densified pyrope glasses upon the cold compression using the high-resolution ²⁷Al MAS and 3QMAS NMR. The fractions of highly coordinated Al in the cold compressed pyrope glasses increase with increasing oil load and thus, the peak pressure condition. Based on known relationship between the peak pressure and the Al coordination environment in the compressed pyrope glasses at room temperature, we established a room temperature pressure-load calibration of the 14/8 HT assembly in 1,100-ton multi-anvil press. The current results highlight the first pressure-load calibration of any high pressure device using high-resolution NMR. Irreversible structural densification upon cold compression observed for the pyrope glasses provides insights into the deformation and densification mechanisms of amorphous earth materials at low temperature and high pressure conditions within the subducting slabs.

• Journal of Bio-Environment Control
• /
• v.31 no.1
• /
• pp.43-51
• /
• 2022

This study was conducted to investigate the effect of ventilation at high temperature on the control of powdery mildew, silverleaf whitefly two-spotted spider mite occurred at Korean melon cultivation greenhouse, and on leaf rolling and flowering of the plant in summer season. 'Alchanggul' grafted onto 'Hidden Power' rootstock was planted on soil bed with the distance of 40 cm. Three ventilation temperatures of 45℃, 40℃, and 35℃ as set points were compared. Ventilation treatment was done by control of side window operation from 18th June to 13th July when silverleaf whitefly, mite, and powdery mildew were occurred in all greenhouses. The temperature inside greenhouse was increased up to the set temperature point on sunny days and maintained for about 9 hours with high relative humidity at 45℃ condition. The differences of day maximum air temperature and day minimum RH were the highest at 45℃ treatment. After 11 days of treatments, the damage by powdery mildew and two-spotted spider mite was almost recovered at 45℃ treatment but not at 40 and 35℃. The population of silverleaf whitefly and two-spotted spider mite were significantly decreased at 45℃ treatment at 14 days after treatment, while powdery mildew symptom was not significantly decreased. Leaf rolling was observed at high temperature but not severe at 45℃ treatment. After 26 days of treatments, female flowers did not bloom at all at 45℃ treatment, and the number of male flowers was 1.2 among 15 nodes of newly grown shoots. As the result, it indicates that ventilation at the high temperature of 45℃ for about 2 to 3 weeks can be an applicable method to control above mentioned pests and disease, and to recover the vegetative growth of Korean melon by reducing flowering of the plant.

• Journal of Bio-Environment Control
• /
• v.31 no.2
• /
• pp.90-97
• /
• 2022

This study was carried out to investigate the effect of side vent heights on temperature and relative humidity inside and outside the single-span plastic greenhouse (W: 7 m, L: 40 m H: 3.9 m) during natural ventilation. Four different heights (120, 100, 80, 60 cm) of the side vent were used as an experimental condition. Variations of temperature and relative humidity inside and outside the greenhouse and the differences between heights were compared by using one-way ANOVA. In the daytime, the difference in temperature between inside and outside the greenhouse was dropped from 14.0℃ to 7.1℃ as the side vent height increased. The temperature difference in the nighttime was less than 0.2℃ regardless of the height. One-way ANOVA on the temperature difference between heights presented that the statistical significance was founded between all of the combinations of height in the daytime. The difference in relative humidity between inside and outside the greenhouse was grown from -13.8% to -22.2% with a decrease in the side vent height. The humidity difference in the nighttime was less than 1% regardless of the height. One-way ANOVA on the humidity difference revealed that most of the side vent heights showed significance in the daytime but between 100 and 80 cm was not significant. It seemed because the external air became cooler during the experiment with a height of 80 cm. Conclusively, this study empirically demonstrated that the higher side vents resulted in the decrease of differences in temperature and relative humidity between inside and outside the greenhouse, and also the effect of side vent height was statistically significant. This study may be helpful for deciding the height of the side vent effective for controlling temperature and relative humidity in a single-span greenhouse during natural ventilation.

• Journal of Bio-Environment Control
• /
• v.31 no.3
• /
• pp.163-169
• /
• 2022

This study was conducted to examine an alternative cultivating method that uses coir substrates in a hydroponically cultured system. Three treatment conditions were applied with one-layer substrate (10 cm height) with a coir chip and dust ratio of 5:5 (Treatment A), two-layer coir substrate (20 cm height) with a coir chip and dust ratio of 5:5 (Treatment B), one-layer coir substrate (15 cm height) with a coir chip and dust ratio of 7:3 (Treatment C). The control condition was a plastic container filled with a coir chip and dust ratio of 5:5. Various criteria were measured and compared between the treatments and the control. The yield of strawberry was smaller in the control than in the treatments. No significant difference in growth characteristic was found in the height treatments of the coir substrates. The net photosynthetic rate of the treatments was 14.68-15.76 µmol CO₂·m^-2·s^-1. This does not show a statistically significant difference. The root activity was better in treatment B and C than in treatment A and the control. The length and width of leaves were measured as 4.04-4.13 cm and 3.26-3.34 cm. These results are not statistically significant. The leaf length and width ratio was 1.27 in the control and 1.24 in the treatments. The findings show that no statistically significant benefit was found when utilizing coir substrates with different height treatments in the hydroponic culture system. However, the harvested fruit per plant weights 72.38 g in treatment A and 48.69 g in treatment C. The number of harvested fruit was least in treatment C in which a coir chip and dust ratio of 7:3 was applied. Therefore, further research is needed to examine how the chip and dust ratio in coir substrate affects growth characteristics.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.6
• /
• pp.955-964
• /
• 2022

According to the statistics of maritime accidents statistics that have occurred in Korea over the past five years, maritime accidents caused by fishing boats have increased every year from 1,646 in 2016 to 2,100 in 2020. In particular, of the 378 capsizing accidents that have occurred in the past five years, 252 capsizing accidents of fishing boats account for a high proportion of 66.7%, therefore, it is urgent to come up with countermeasures. In this study, to determine the cause of the capsizing accident of fishing boat No. 66 poongsung, data such as stability and seawater inflow routes were collected, and the effects of waterproof, additional wood decks, and windbreakers on stability on were quantitatively analyzed. Additional decks, windbreakers, and waterproof installed in No. 66 poongsung cause initial list, deteriorate stability, and fail to meet fishing boat structural standards. In addition, it was analyzed that the stability was weakened due to the characteristics of the hull shape of No. 66 poongsung. To estimate the stability at the time of the accident, the stability at the time of the working in the fishing ground condition, amount of seawater inflow according to the change in sea conditions, hull oscillation situation, and change in stability due to the hull factor were calculated. As a result, the minimum GoM was satisfied at the time of working in the fishing ground, but it could not be restored at the maximum wave height of 4 m, and the minimum GoM was not satisfied at the maximum wave height of 4 m owing to the influence of seawater inflow and oscillation due to the hull list. However, the minimum GoM was satisfied if additional decks and windbreakers installation was excluded among the factors affecting the stability of No. 66 poongsung.

• Journal of Bio-Environment Control
• /
• v.32 no.1
• /
• pp.64-71
• /
• 2023

Crassulacean acid metabolism (CAM) plants use surplus CO₂ generated by cooling and heating at night when ventilation is not needed in a greenhouse. Schlumbergera truncata 'Pink Dew' is a multi-flowering cactus that needs more phylloclades for high-quality production. This study examined photosynthetic characteristics by the phylloclade levels of S. truncata in a growth chamber and a greenhouse for use of night CO₂ enrichment. The CO₂ uptake rate of the S. truncata's top phylloclade in a growth chamber exhibited a C₃ pattern, and the second phylloclade exhibited a C₃-CAM pattern. The CO₂ uptake rate of the top phylloclade in a greenhouse showed a negative value both day and night, but those of the second phylloclade exhibited a CAM pattern. The stomatal conductance and water-use efficiency (WUE) of S. truncata at both the top and second phylloclades were higher in a growth chamber than in a greenhouse. The WUE of S. truncata in a growth chamber and a greenhouse was higher at the second phylloclade, which is a CAM pattern compared with those of the top phylloclade. The daily total net CO₂ uptake of S. truncata was higher in a growth chamber than in a greenhouse. The daily total net CO₂ uptake of S. truncata at the second phylloclade had the highest value of 155 mmol·m^-2·d^-1 in a growth chamber. The night total CO₂ uptake of S. truncate at the second phylloclade was 3-fold higher in a growth chamber than in a greenhouse. S. truncata's second phylloclade exhibited a CAM pattern that uptake CO₂ at night, and the second phylloclade, was more mature than the top phylloclade. A multi-flowering cactus S. truncata 'Pink Dew' efficiently uptake night surplus CO₂ in the proper environmental condition with matured phylloclade.

• Journal of Bio-Environment Control
• /
• v.32 no.1
• /
• pp.48-56
• /
• 2023

High-pressure sodium (HPS) lamps have been widely used as a useful supplemental light source to emit sufficient photosynthetically active radiation and provide a radiant heat, which contribute the heat requirement in greenhouses. The objective of this study to analyze the thermal characteristics of HPS lamp and thermal behavior in supplemented greenhouse, and evaluate the performance of a horizontal leaf temperature of sweet pepper plants using computational fluid dynamics (CFD) simulation. We simulated horizontal leaf temperature on upper canopy according to three growth stage scenarios, which represented 1.0, 1.6, and 2.2 plant height, respectively. We also measured vertical leaf and air temperature accompanied by heat generation of HPS lamps. There was large leaf to air temperature differential due to non-uniformity in temperature. In our numerical calculation, thermal energy of HPS lamps contributed of 50.1% the total heat requirement on Dec. 2022. The CFD model was validated by comparing measured and simulated data at the same operating condition. Mean absolute error and root mean square error were below 0.5, which means the CFD simulation values were highly accurate. Our result about vertical leaf and air temperature can be used in decision making for efficient thermal energy management and crop growth.