Effects of Long-term Exposure of High and Low Humidity on Thin-film Humidity Sensors

( Sang-wook Lee ),( Byung Il Choi ),( Jong Chul Kim ),( Sang-bong Woo ) 한국센서학회 2018 센서학회지 Vol.27 No.6

The effects of long-term exposure of high and low humidity on thin-film humidity sensors are investigated. Five commercially available thin-film humidity sensors are initially calibrated in a humidity chamber as a reference before longterm exposure to high and low humidity. Then, the sensors are kept in a high-humidity environment (~95 %rh) for four months. After the exposure, the sensors are calibrated in the same manner as the initial calibration. Consequently, the device reading values from the humidity sensors are elevated up to about 5 %rh. Interestingly, the degree of elevation by the high-humidity exposure shows a negative correlation with the price of the humidity sensors. Humidity sensors are then kept in a low-humidity environment (~10 %rh) for another four months. After the exposure, a calibration similar to the initial calibration is performed. As a result, the device reading from humidity sensors is decreased, indicating a recovery from the effect of high-humidity exposure. The durability test conducted in this study provides experimental evidence for the use of thin-film humidity sensors in high-humidity environments such as greenhouses and food factories for a long period of time.

고온 환경에서 유산소 트레이닝 시 습도조절이 신체조성, 혈중지질 및 젖산에 미치는 영향

김정대(Kim, Cheong-Dae),신세영(Shin, Se-Young),진승모(Jin, Seung-mo),김원중(Kim, Won-jung) 한국사회체육학회 2021 한국사회체육학회지 Vol.- No.84

Purpose: The purpose of this study is to investigate the effect of 8 weeks of aerobic training according to the difference in humidity in a high-temperature environment on body composition, blood lipid factors, and changes in lactate. Method: The subjects of the study were healthy men living in S city, who were explained the purpose and method of this study fully and voluntarily expressed their intention to participate (N=30). The group was randomly set into a normal humidity group (n=15) and a high humidity group (n=15). The temperature of the training environment was set to 33.0±1.0°C, and the humidity setting was set to 50.0±3.0% for the normal humidity group and 70.0±3.0% for the high humidity group, and training with 60% intensity of V·O₂max was performed 3 times a week for 8 weeks. Measurement variables weer body composition, blood lipids, and lactate. All statistics were analyzed by SPSS ver 24.0, and paired t-tests were used to verify the differences between before and after training. Repeated measure ANOVA was performed to examine the effects between groups and periods. All statistical significance levels were set at p<.05. Results: The results of this study are as follows. 1) There was no significant change in skeletal muscle mass in the body composition variable, but there was a significant decrease in body fat (p<.05). 2) For blood lipids, HDL-C, LDL-C, GLU, and TG excluding TC showed improvement effects, and significant differences between the periods (p<.05, p<.01, p<.001). 3) There were no significant differences in each variable in the case of blood lactate. Conclusion: In conclusion, training according to humidity environment can expect improvement effect on the human body. However, it is thought that clear distinction, control of training environment and living environment are needed because continuous exposure to high humidity can cause various diseases.

예비천연건조가 잣나무 중목구조부재의 고온저습건조 특성에 미치는 영향

이창진 ( Chang Jin Lee ),이남호 ( Nam Ho Lee ),박문재 ( Moon Jae Park ),박주생 ( Joo Saeng Park ),엄창득 ( Chang Deuk Eom ) 한국목재공학회 2014 목재공학 Vol.42 No.1

최종함수율은 예비천연건조를 수행한 시험재에서 더 균일하게 건조가 가능하였으며, 예비천연건조 후 고온저습건조시 최종함수율은 초기함수율에 영향을 받는 것으로 사료된다. 재면할렬 억제 효과는 예비천연건조를 수행한 시험재에서 더 효과적인 것으로 조사되었으나, 예비천연건조 중 발생된 재면할렬에 의한 영향이 크기 때문에 예비천연건조 중 할렬발생 억제가 중요할 것으로 판단된다. 부분엔드코팅은 내부할렬, 표면경화율, 비틀림, 수축율에 미치는 영향이 없는 것으로 조사되었다. 예비천연건조는 고온저습건조 중 내층에 발생하는 인장응력을 감소시켜 내부할렬의 발생을 매우 효과적으로 억제하고 표면경화율을 감소시키는 것으로 조사되었다. 비틀림의 경우 함수율감소에 따른 수축으로 인하여 비틀림의 정도가 증가되었다. The pre-air-drying of Korean pine before the high-temperature and low-humidity drying was shown to be effective in uniform moisture content distribution and prevention of surface check. Our results suggest that initial moisture content of the timber also plays important role in high-temperature and low-humidity drying method. The pre-air-drying also helps in the reduction of surface checks in Korean pine when compared to the Korean pine dried by only high-temperature and low-humidity. End-coating was not effective in the prevention of twist, shrinkage, case hardening and internal checks. The pre-air-drying reduces the internal tension stresses which occur during high-temperature and low-humidity drying thus decreasing case hardening and also preventing internal checks. The pre-air-drying decreases the moisture content and causes shrinkage which leads to increased twist in the Korean pine.

One Lambda LABTypeTM을 이용한 HLA- DR Typing시 나타나는 위양성과 위음성, High-Background 사례와 검사실 습도의 관계분석

Hyang Son AN,Minsung SOHN 대한임상검사과학회 2023 대한임상검사과학회지(KJCLS) Vol.55 No.3

Human leukocyte antigen (HLA) typing was performed in the diagnostic immunology laboratory of the Seoul National University Hospital. Among 611 HLA-DR tests, specific bead reactions suspected of being false positive and false negative in Lot 20 reagents were found. Therefore, we aimed to identify the factors causing cut-off corrections by examining cases where cut-off corrections were not made for 533 test results and cases where cut-off corrections were made for 78 cases after the cut-off corrections of specific beads. Frequency analysis was conducted to verify the demographic characteristics, and descriptive statistics were used to assess the humidity in the laboratory as a variable. Cross-tabulation was done to examine the association between cut-off corrections and demographic characteristics. Independent samples t-tests were conducted to verify the difference in humidity based on cut-off corrections. Finally, logistic regression analysis was conducted to examine the relationship between humidity levels and the rate of cut-off corrections, and results showed as the humidity level in the laboratory highs, the number of cut-off corrections decreased by a factor of 0.986. This suggests cut-off corrections rate increases when the humidity lowers. Therefore, it indicates that humidity in the laboratory is also a factor that affects HLA typing results.

고품질 표고버섯 (Lentinus edodes(Berk.) Sing) 의 생육환경 분석

손정익 서울대학교 농업개발연구소 2000 농업생명과학연구 Vol.4 No.-

Oak mushroom(Lentinus edodes(Berk.) Sing) is one of the most important edible mushrooms, and its production has been rapidly increased due to nutritional and medicinal effects. In this study, regional climatic factors during the growing period of high-quality oak mushroom were analyzed and environmental condition affecting the quality were discussed. Three places as mass production areas of high-quality mushrooms and the 15 days as a standard growing period in 1997-1998 were selected. Major climatic factors were average air temperature and relative humidity, diurnal ranges of air temperature and relative humidity, and wind speed. During the period, the daily average air temperature was 5 to 15℃ with a diurnal range of -2~20℃ and the relative humidity was 40 to 60% with a diurnal range of 50~60%. Wind velocity was over 1 m/s. All the results showed that environmental conditions such as wide ranges of air temperature and relative humidity, low humidity, and wind speed affected the formation of high-quality oak mushroom. Moreover, the environmental conditions suitable for high quality differed from those for high productivity.

Improvement of the Strength of Acrylic Emulsion Polymer-modified Mortar in High Temperature and High Humidity by Blast Furnace Slag

권혁문,Thuy Ninh Nguyen,Tuan Anh Le 대한토목학회 2009 KSCE JOURNAL OF CIVIL ENGINEERING Vol.13 No.1

Polymer modification was widely used to improve the properties of construction materials. The concept of polymer modification for mortar and concrete was put forward 80 years ago. It was known that the use of polymers for modification can greatly improve the strength, adhesion, resilience, impermeability, chemical resistance and durability properties of mortars and concrete. In southern Vietnam, a tropical weather country, the environment was usually hot with high humidity. The durability of mortar or concrete coating was reduced over time in such a condition. This study examines the strength of polymer-modified mortars in high temperature and high humidity. Moreover, the results included the improvement of strength of acrylic emulsion polymer-modified mortar (PMM) by the addition of blast furnace slag. Fifteen percent cement was replaced with blast furnace slag (BFS) in a mix proportion in order to improve strength of PMM. The specimens were cured in cycles 50±2˚C, RH 90±3%, for 5 hours and 20±2˚C, RH 60±3%, for 19 hours per day. The strength of PMM was measured at the age of 3, 7, 14, 21 and 28 days, 3 and 6 months and 1 year in a high temperature and high humidity cycles.

무연솔더를 적용한 자동차 전장부품의 기계적 접합강도 및 오차 범위에 관한 연구

윤준호,전유재 한국기계기술학회 2015 한국기계기술학회지 Vol.17 No.6

This study has assessed mechanical bonding strength of lead-free solder joint. Assessment methods was performing long-term reliability test about thermal shock, thermal life and high temperature & high humidity. Based on the results of analyzing mean values that was obtained from repetion of 5 times according to each conditions, reduction of mechanical bonding strength of each tests was confirmed. When it comes to HB chip, the order of high deviation rate was shown thermal shock, high temperature & humidity and thermal life. And the higher deviation rate of R0 is high temperature & humidity, thermal life and thermal shock. The order of high deviation rate of C1 chip is high temperature & humidity, thermal shock and thermal life. Related to this result of experiment, the most stable error range of mechanical bonding strength is established. From now on optimized quantity of solder and shape of solder-joint is needed by establishing a test method which can make error range of mechanical bonding strength minimize.

고온다습한 환경이 CFRP 복합재료의 정적강도 거동 특성에 미치는 영향

홍석우(Suk Woo Hong),강민성(Min Sung Kang),안상수(Sang Soo Ahn),구재민(Jae Mean Koo),석창성(Chang Sung Seok) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10

Recently, the use of Carbon Fiber Reinforced Plastic(CFRP) composite have been increased instead of metal material in the field which highly demands both lightweight and high specific strength materials such as aircraft and automobile. In the aircraft operating condition, the fuselage of aircraft is often exposed to severe condition between high temperatures and high humidity. Therefore, the estimation of strength properties of CFRP under real condition is highly necessary for the aircraft safety. In this study, CFRP specimens were made according to ASTM D3039, and tensile tests was performed at 75℃ and high humidity condition. After the tensile tests, fractured surfaces were analyzed to estimate the characteristics the CFRP composite in high temperature and humidity conditions using SEM.

무연솔더를 적용한 자동차 전장부품의 기계적 접합강도 및 오차 범위에 관한 연구

윤준호,전유재 한국기계기술학회 2015 한국기계기술학회지 Vol.17 No.6

This study has assessed mechanical bonding strength of lead-free solder joint. Assessment methods was performing long-term reliability test about thermal shock, thermal life and high temperature & high humidity. Based on the results of analyzing mean values that was obtained from repetion of 5 times according to each conditions, reduction of mechanical bonding strength of each tests was confirmed. When it comes to HB chip, the order of high deviation rate was shown thermal shock, high temperature & humidity and thermal life. And the higher deviation rate of R0 is high temperature & humidity, thermal life and thermal shock. The order of high deviation rate of C1 chip is high temperature & humidity, thermal shock and thermal life. Related to this result of experiment, the most stable error range of mechanical bonding strength is established. From now on optimized quantity of solder and shape of solder-joint is needed by establishing a test method which can make error range of mechanical bonding strength minimize.

Effects of metakaolin and PVA fiber on the compressive strength of shotcrete under different curing conditions

Yang Guoqiang,Guo Gang,Wang Lihui,Wang Changchang,Sun Tao 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.3

In this paper, wet shotcrete spraying experiments were carried out under different temperature and humidity conditions withdifferent dosage of metakaolin (MK) and different length of polyvinyl alcohol fiber (PVA fiber). And the influence of differentcontent of metakaolin and different length of PVA fiber on the compressive strength of tidal shotcrete under different curingconditions was explored. The results show that the compressive strength of shotcrete increases first and then decreases withthe increase of MK content and PVA fiber length under the curing condition of normal temperature and constant humidity. However, under the curing condition of high temperature and humidity, the compressive strength of shotcrete tended toincrease with the increase of MK content. Under the condition of high temperature and high humidity curing, the compressivestrength of shotcrete is lower than that of shotcrete under normal temperature and constant humidity curing. This study canprovide theoretical support for the application of sprayed concrete in different environments.