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.

습도 변화가 눈에 미치는 영향

한선희,김봉환,김소빈,김민정,박희경,김현지,김헌태,김형수,Sun-Hee Han,Bong-Hwan Kim,So-Bin Kim,Min-Jung Kim,Hee-Kyung Park,Hyun-Ji Kim,Heon-Tae Kim,Hyeong-Su Kim 한국임상보건과학회 2023 한국임상보건과학회지 Vol.11 No.1

Purpose. The purpose of this study was to investigate the effect of changes in tear break-up time, accommodative response amount, and accommodative microwave on the eyes due to changes in humidity. Methods. A total of 48 adult men and women in their 20s (21.1±1.56 years old) were surveyed on dry eye questionnaires (OSID questionnaires), tear destruction time was measured by humidity (40%, 60%, 80%), and controlled reactions and controlled fine waves were measured through tactile tests. Result. As a result of the OSID questionnaire, there were 10 normal patients, 8 mild dry eyes, 1 moderate dry eye, and 5 severe dry eyes. The initial tear film destruction time was 7.34±4.67 seconds at 40% humidity, 8.99±4.75 seconds at 60% humidity, 10.26±4.52 seconds at 80% humidity, and the average tear film destruction time was 9.51±4.07 seconds at 40% humidity, 10.99±3.82 seconds at 60% humidity, and 12.05±3.42 seconds at 80% humidity. The accommodative response was -0.41~1.79D at 40% humidity, -0.34~1.79D at 60% humidity, and -0.30~2.01D at 80% humidity. The accommodative microwave was measured as 56.39~63.43dB when it was 40%, 56.41~62.64dB when it was 60%, and 55.96 ~61.13dB when it was 80%. Conclusion. As the humidity (40~80%) increased, the tear break-up time increased, and as the accommodative stimulus amount increased, the accommodative response amount increased. It was found that the accommodative microwave according to the amount of accommodative stimulation increased, and as the humidity increased, the accommodative microwave decreased.

Evaluation of Temperature and Humidity of a Thermo-Hygrostat of PET/CT Equipment using a Temperature and Humidity Sensor(BME 280)

류찬주(Chan-Ju Ryu),김정아(Jeong-A Kim),김준수(Jun-Su Kim),윤근영(Geun-Yeong Yun),허승희(Seung-Hui Heo),홍성종(Seong-Jong Hong) 한국방사선학회 2020 한국방사선학회 논문지 Vol.14 No.1

PET(Positron Emission Tomography)장치는 해부학적 정보를 얻기 위한 CT와 MRI의 장치를 PET 장치와 융합시킨 PET/CT나 PET/MRI 장치로 사용된다. 그렇기 때문에 일반 의료장비들과 비교하여 Gantry(촬영부 본체)의 길이가 늘어나고 내부의 공간이 넓어지는 원형(ring)타입의 구조로 제작된다. PET 장치의 구성요소 중 하나인 신틸레이터는 Gantry 안쪽에 위치하는데 온ㆍ습도 변화에 민감한 크리스탈 성분으로 되어있기 때문에 커다란 온도 변화로 인해 신틸레이터의 손상을 가져올 수 있다. 신틸레이터는 항온항습기로 PET장치가 설치되어 있는 공간에 온ㆍ습도를 유지하지만 이러한 PET 장치의 구조적 원인과 CT 장비에서 발생하는 열로 인한 Gantry 내부의 온ㆍ습도의 변화가 예상된다. 항온항습기를 가동하여 온ㆍ습도를 유지중인 PET/CT 장치의 Gantry 내부를 6개의 구역으로 나눈 후 각 구역에 Arduino 온ㆍ습도 센서인 Adafruit BME 280을 부착하여 출력 값을 분석했다. 각 6개 구역에서 센서를 이용해 측정한 평균 온·습도 값과 항온항습기의 평균 측정값을 비교하면 평균적으로 온도는 2.71℃ 상승, 습도는 21.5% 감소의 차이가 발생하였고, PET Gantry의 온·습도 측정값은 국내에서 지정한 정도 관리 범위에서 벗어나는 결과 값이 나왔다. 연구결과를 통해 앞으로 지속적인 온·습도의 변화를 가진다면 PET Gantry 안에 장착된 신틸레이터의 노후화가 예상되므로 Gantry구조 내부의 온ㆍ습도를 적절히 유지하는 방안을 모색해야 한다. PET(Positron Emission Tomography) devices are used as PET/CT or PET/MRI devices fused with the devices of CT or MRI for obtaining anatomical information. Therefore, the devices are constructed in circular ring-type structure whose length of gantry(the main part of filming) becomes wider and the interior depth becomes longer in comparison to other common medical equipments. scintillator, one of the components in PET devices, is inside the gantry, and as it is consisted of crystal which is sensitive to the change of temperature and humidity, large temperature change can cause the scintillator to be damaged. Though scintillator located inside the gantry maintains temperature and humidity with a thermo-hygrostat, changes in temperature and humidity are expected due to structural reasons. The output value was measured by dividing the inside of the gantry of the PET/CT device into six zones, each of which an Adafruit BME 280 temperature and humidity sensor was placed at. A thermo-hygrostat keeps the temperature and humidity constant in the PET/CT room. As the measured value of temperature and humidity of the sensor was obtained, the measured value of temperature and humidity appeared in the thermohygrostat was taken at the same time. Comparing the average measured values of temperature and humidity measured at each six zones with the average values of the thermo-hygrostat results in a difference of 2.71°C in temperature and 21.5% in humidity. The measured temperature and humidity of PET Gantry is out of domestic quality control range. According to the results of the study, if there is continuous change in temperature and humidity in the future, the aging of the scintillator mounted in the PET Gantry is expected to be aging, so it is necessary to find a way to properly maintain the temperature and humidity inside the Gantry structure.

제주지역 직장어린이집 보육실의 겨울철 실내온열환경 실태

김봉애(Kim, Bong-Ae),고연숙(Ko, Youn-Suk) 대한건축학회 2017 大韓建築學會論文集 : 構造系 Vol.33 No.12

This study was conducted to investigate the thermal environment status of nursery rooms in workplace daycare centers in Jeju and propose measures to improve their indoor physical thermal environment. For this purpose, measurements were performed in the winter indoor physical environment of 51 nursery rooms in 11 workplace daycare centers and a psychological evaluation survey on the thermal environment of nursery rooms was conducted for 70 nursery teachers. The investigation was carried out over 11 days in January 2017. The results are as follow. The average indoor temperature of the nursery rooms was 21.3℃(18.7-23.8℃) and the indoor temperatures of 47 nursery rooms (92.9%) were higher than the environmental hygiene management standard for domestic school facilities (18-20℃). The average relative humidity was 33.9% (16.4-56.0%), and 37 nursery rooms (86.3%) showed a lower average relative humidity than the standard (40-70%). The average absolute humidity was 9.1g/㎥ (4.7-13.6g/㎥), which was lower than the standard for preventing influenza (10g/㎥). When the indoor temperature and humidity of the nursery rooms were compared with international standards, it was found that 85% or more of the 51 nursery rooms maintained appropriate indoor temperatures, but 40-50% of the nursery rooms maintained a low humidity condition. Therefore, they need to pay attention to maintaining the appropriate humidity of the nursery room to keep the children healthy. The average indoor temperature of the nursery rooms showed a weak negative correlation with the average relative humidity. The indoor temperature had a significant effect on the relative humidity: a higher indoor temperature resulted in lower relative humidity. Regarding the fluctuations in the average indoor temperature of the nursery rooms during the day, in daycare centers that used floor heating, the indoor temperature gradually increased form the morning to the afternoon and tended to decrease during lunch time and the morning and afternoon snack times, due to ventilation. The daycare centers that used both floor heating and ceiling-type air conditioners showed a higher indoor temperature and greater fluctuations in temperature compared to the daycare centers that used floor heating only. In the survey results, the average value of the whole body thermal sensation was 3.0 (neutral): 32 respondents (62.7%) answered, “Neutral”, Which was the largest number, followed by 21 respondents (30%) who answered, “Slightly hot” and 17 respondents (24.2%) who answered, “Slightly cold.” Twenty-nine respondents answered, “Slightly dry,” which was the largest number, followed by 28 respondents (54.9%) who answered, “Neutral” and 10 respondents (19.6%) who answered, “Dry.” The total number of respondents who answered, “Slightly dry” or “Dry” was large at 39 (56.4%), which suggests the need for indoor environment management to prevent a low-humidity environment. To summarize the above results about the thermal environment of nursery rooms, as the indoor temperature increased, the relative humidity decreased. This suggests the effect of room temperature on the indoor relative humidity; however, frequent ventilations also greatly decrease the relative humidity. Therefore, the ventilation method and the usage of air conditioning systems need to be re-examined.

전도성 카본 잉크를 이용한 직류 저항형 습도센서 제작 및 평가

안태창 ( Taechang An ) 한국센서학회 2017 센서학회지 Vol.26 No.6

A DC resistance type humidity sensor using conductive carbon ink was fabricated and its performance was evaluated. The humidity sensor was fabricated using a screen printing technique and have a structure that does not require additional metal electrodes to measure resistance change. To evaluate the performance of the humidity sensor, we measured the DC resistance change under various relative humidity levels. The fabricated humidity sensor showed a resistance change of about 2.5 ~ 50 kΩ in 11 ~ 95% RH environment. It also shows a linear relationship in the relative humidity versus log DC resistance graph. In comparison with commercial humidity sensor under real environment, it can be confirmed that the resistance of the humidity sensor changes to almost the same level as the measured humidity. These results show that the resistance type humidity sensor can be operated stably in actual environment.

Experimental study of humidity control methods in a light-emitting diode (LED) lighting device

김철숙,이진규,조지현,김동연,서태범 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.6

Light-emitting diode (LED) lights can reduce greenhouse gas emissions significantly by using electrical energy efficiently. However,the sensitive characteristics of an LED change with temperature and humidity. Humidity is directly related to performance degradation(The durability and efficiency) of electronic devices, including LED lights. Solving the problem of heating or humidity is important toensure the reliability of an LED product. We examined commercially available humidity control methods, and experimented with MILSTD-810G (Military Standards United States) to evaluate humidity on the global climatic environment. As a result, even though an LEDlight satisfies the IP66 grade, if it has an air vent, there is a strong possibility that condensation will occur in the lamp during a suddenchange of temperature and humidity in an environment of high temperature and humidity. Because methods of using heat pipes and fansincrease the dry-bulb temperature, the relative humidity (RH) decreases slightly. In the case of the thermoelement method, when thethermoelement was working, the humidity ratio was about 0.0185. When it was not working, the humidity ratio was about 0.0215. In thecase of the absorbent method, when absorbent was in the lamp, the humidity ratio was about 0.008. Comparing two tests, the water vaporin the air decreased by 64%.

한지(韓紙)가 실내습도조절에 미치는 영향에 관한 실험적 연구

이종원,임정명 대한설비공학회 2004 설비공학 논문집 Vol.16 No.6

The purpose of this study is to reevaluate the performance of Hanji as an architectural material. Hanji has good things in controlling indoor space comfortably. Particularly, ability of controlling humidity of Hanji affects indoor space comfort and human health. The major focuses of this experimental research are (1) how much of water vapor passes through Hanji, (2) how much of water vapor is absorbed into Hanji. In the first case, indoor humidity is higher than outdoor humidity. In this case, approximately 38 g of water vapor passes through Hanji 1, genarally utilized in window paper (Changhoji), per square meter in one hour. And approximately 4 g of water vapor is absorbed into Hanji 2, genarally utilized in wallpaper, per square meter. In the second case, outdoor humidity is higher than indoor humidity. In this case, Hanji passes water vapor to inner space at first, but when indoor relative humidity reach approximately 66%, although outdoor humidity is higher than indoor humidity, water vapor doesn't pass through Hanji. If Hanji is utilized in window material and wallpaper, indoor space is maintained comfortably without mechanical devices in humidity control.

Enhanced Graft-take Ratio and Quality of Grafted Tomato Seedlings by Controlling Temperature and Humidity Conditions

Ngoc-Thang Vu,김일섭,장성호,서지호,김영식,강호민 (사) 한국생물환경조절학회 2013 시설원예‧식물공장 Vol.22 No.2

This study was conducted to enhance graft-take ratio and quality of grafted tomato seedlings by controllingtemperature and humidity during the healing and acclimatization processes. Three temperature levels (20℃,23℃, and 26℃) were carried out to determine optimum temperature on four rootstocks. In addition, twelve combinationsof three relative humidity levels (70%, 80%, and 90%) and four temperature levels (17℃, 20℃, 23℃, and26℃) were set up to evaluate the effect of relative humidity and temperature on the graft-take ratio of grafted seedlings. In the other hand, five relative humidity periods (H0, H1, H2, H3, and H4: 90% relative humidity for first 0, 1,2, 3 and 10 days and afterwards relative humidity was reduced to 70%, respectively) were examined effect of relativehumidity periods on the graft-take and quality of grafted seedlings. The higher graft-take ratios (84.0~87.4%)were showed at 23℃ compared to 20℃ and 26℃ in all rootstocks. Graft-take ratios decreased and number of diseasedplants increased at high temperature. The graft-take ratios increased with increasing relative humidity in alltemperature levels on the 3rd and 7th day after grafting. However, increasing relative humidity significantly increasedpercent of diseased plants. The graft-take ratio reduced at (26℃) and (17℃) temperature under all relative humidityconditions. The graft-take ratio increased with increasing period of 90% relative humidity. Maximum graft-takeratios were observed in H2 and H3 treatments. Graft-take ratio decreased with increasing 90% relative humidity for10 days (H4). Diseased plants had not been found in H0, H1, H2, and H3 treatments. Seedling quality was improvedthrough increasing fresh and dry weight of root, compactness, and root morphology of tomato seedlings in H2 andH3 treatments. Therefore, high relative humidity (90%) for first 2 or 3 days and afterwards reduced low relativehumidity (70%) at 23℃ condition during healing and acclimatization promoted the graft-take and quality of graftedtomato seedlings.

Research on the Temperature & Humidity Monitoring System in the Key Areas of the Hospital Based on the Internet of Things

Benzhen Guo,Xiaojing Wang,Xiao Zhang,Jingjing Yang,Zhihui Wang 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.7

This paper designs an internet of things-based temperature & humidity monitoring system in the key areas of the hospital to address the problem that the temperature and humidity monitoring systems are independent from each other in the hospital. The establishment of a hospital-level temperature and humidity monitoring platform is able to realize the integrated monitoring and management on such areas as ICU, pharmacy and operation room etc, where both of the temperature and humidity must be monitored. In every temperature and humidity acquisition node, the collected environmental data about the indoor humidity and temperature will be sent over the 433M wireless sensor network to the internet of things (IoT) gateway, through which data will be uploaded via wifi or the wired access network within the hospital to the background server, where in addition to data collection and analysis, various reports will be generated and control commands will be transferred. Then all of the medical staffs can make a real-time inquiry and control on the environmental data by connecting their intelligent terminals (such as cell phone) to the server. Actually when the humidistat thermostat controller is designed according to the DDC principle and the integral-separation PID control algorithm, the control on the central air-conditioning units is able to realize the real-time control of constant temperature and humidity. Also a prototype system has been established to conduct the functional verification. The experiment shows that this system is able to run steadily with precise data collection and reliable control.

온도와 습도에 따른 건조사암의 전기비저항 특성

이태종,이상규 한국자원공학회 2014 한국자원공학회지 Vol.51 No.1

A laboratory electrical resistivity measurement system in controlled temperature and humidity condition has been set up. Using the system, resistivity of a dry sandstone has been measured in various temperature and humidity conditions. Electrical resistivity showed very strong dependance on the temperature and humidity, maximum 232 times difference when relative humidity and temperature are in the ranges of 45∼85% and 20∼40℃, respectively. Electrical resistivity decreases when temperature and/or humidity increase. Ten percent change of relative humidity gives stronger effects to electrical resistivity than 5℃ of temperature change. It needs more than 7 days for the sample to reach equilibrium condition with the temperature and humidity inside the chamber,so that an asymptotic equation has been suggested to estimate the resistivity in equilibrium. The estimated resistivity showed clearer negative dependance on both temperature and humidity. Especially, it shows very clear negative linear dependancy between resistivity and relative humidity in log-linear scale. 항온 ・항습 환경에서 건조한 암석 시료의 전기비저항을 측정할 수 있는 시스템을 구축하였다. 이를 이용하여 수포화 하지 않은 건조한 사암 시편을 이용해서 온도와 습도를 달리하며 전기비저항을 산출하고 온도 및 습도에 따른 건조사암의 전기비저항 특성을 고찰하였다. 상대습도가 45∼85% 범위, 온도가 20∼40℃ 범위에서 전기비저항을 10시간 측정할 때 측정되는 전기비저항은 온도와 습도에 크게 좌우되어 최대 232배의 차이를 보였다. 온도와 습도가 높아짐에 따라 전기비저항은 낮아지는 반비례관계를 보이며, 동일한 온도일 때에 습도가 10% 씩 변화하는 경우가 동일한 습도일 때에 온도가 5℃ 씩 변화하는 경우보다 더 강하게 영향을 받는다. 많은 경우에 시편 내부의 온 ・습도가 항온 ・항습기 내부의 설정 온 ・습도와 평형을 이루기 위해서는 7일 이상의 시간이 소요되어 적절한 점근식을 제안하였다. 이를 통해 추정한 평형상태의 전기비저항은 온도와 습도와 더욱 뚜렷한 반비례 관계를 보이며, 특히 습도와 전기비저항의 log값은 선형적 반비례 관계를 보인다.