• Title, Summary, Keyword: Humidity

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

  • Lee, Sang-Wook;Choi, Byung Il;Kim, Jong Chul;Woo, Sang-Bong
    • Journal of Sensor Science and Technology
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    • v.27 no.6
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    • pp.368-373
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    • 2018
  • 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.

The Application of Humidity Indicators for Environmental Measurement Apparatus of Preservation Facility (문화재 보존시설에서의 습도지시카드 적용성 연구)

  • Lim, Bo-A;Shin, Eun-jeong;Do, Min-Hwan
    • 보존과학연구
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    • pp.47-61
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    • 2009
  • Cultural heritages are affected by various environmental factors. Main factors are temperature, humidity, light and indoor air pollutants such as ozone, nitrogen oxides. Especially humidity condition is very important. Low humidity condition can cause contraction and high humidity condition can lead to growth of microorganism. This study is conducted to appraise an applicability of the Humidity Indicator which is one of the simple method for humidity control. The Humidity Indicator shows the humidity conditions through color change. Therefore, photometer was used to correctly measure the color change of Humidity Indicator. As a result of lab test, Humidity Indicators was stabilized after one hour from en exposure in a certain humidity condition and the indicators indicated clear correlations between color changes of Humidity Indicators and humidity conditions. Some Humidity Indicators which had been selected through the lab tests were applied to preservation facilities of cultural heritages and the indicators indicated closed correlations with humidity conditions in indoor of facilities.

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A Surface Humidity Model of Drying Concrete Immediately after Placement (타설 직후 건조하는 콘크리트의 표면습도 모형)

  • Jeong, Jin-Hoon
    • International Journal of Highway Engineering
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    • v.7 no.3
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    • pp.23-30
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    • 2005
  • Predicting distribution and variation of humidity inside concrete is essential to improve curing quality of concrete at field. The concrete humidity is predicted by numerical analysis using surface humidity as boundary condition. However, ambient humidity has been used instead of the surface humidity because the surface humidity could not be ccurately measured. Because it is hard to accurately measure the surface humidity, owever, the ambient humidity has been used instead of the surface humidity in the numerical analysis. In this paper, a methodology to accurately measure the surface humidity is suggested, and the ambient humidity and the humidity at the surface and inside the concrete measured by a series of laboratory tests are presented. The cause of low concrete humidity immediately after placement was investigated by a separately performed test. A surface humidity prediction model was developed using the measured humidity, and consequently validated through an additional test.

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Evaluation of DC Resistive Humidity Sensors Based on Conductive Carbon Ink (전도성 카본 잉크를 이용한 직류 저항형 습도센서 제작 및 평가)

  • An, Taechang
    • Journal of Sensor Science and Technology
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    • v.26 no.6
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    • pp.397-401
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    • 2017
  • 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 $2.5{\sim}50k{\Omega}$ 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.

Humidity Calibration for a Pressure Gauge Using a Temperature-Stable Quartz Oscillator

  • Suzuki, Atsushi
    • Applied Science and Convergence Technology
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    • v.25 no.6
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    • pp.124-127
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    • 2016
  • Humidity calibration for a temperature-stable quartz oscillator (TSQO) was investigated to exclude the influences of relative humidity on the TSQO output in order to use the corresponding devices outdoors. The TSQO output is a voltage that is inversely proportional to the electric impedance of the quartz oscillator, which depends on the viscosity and density of the measured gas. The TSQO output was humidity calibrated using its humidity dependence, which was obtained by varying the relative humidity (RH) from 0 to 100 RH% while other conditions were kept constant. The humidity dependencies of the TSQO output were fit by a linear function. Subtracting the change in the TSQO output induced by the change in humidity, calculated with the function from the experimentally measured TSQO output for a range of 0-100RH%, eliminated the influence of humidity on the TSQO output. The humidity calibration succeeded in reducing the fluctuations of the TSQO output from 0.4-3% to 0.1-0.3% of the average values for a range of 0-100RH%, at constant temperatures. The necessary stability of the TSQO output for application in hydrogen sensors was below one-third of the change observed for a hydrogen leakage of 1 vol.% hydrogen concentration, corresponding to 0.33% of the change in each background. Therefore, the results in this study indicate that the present humidity calibration effectively suppresses the influence of humidity, for the TSQO output for use as an outdoor hydrogen sensor.

A Study on Physical Properties of Carbon Nitride Films and Application of Sensor Materials (질화탄소막의 물리적 특성과 센서재료 응용에 관한 연구)

  • Kim, Sung-Yeop;Lee, Ji-Gong;Chang, Choong-Won;Lee, Sung-Pil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.247-248
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    • 2006
  • Carbon nitride films were evaluated that they had many advantages for miniature micro-humidity-sensors using the standard CMOS technology humidity sensing properties and CV characteristics of the carbon nitride films have been investigated for fabricating one chip HUSFET(Humidity Sensitive Field Effect Transistor) humidity sensors Carbon nitride films were deposited on silicon substrate with meshed electrodes by reactive RF magnetron sputtering system. The capacitor-type humidity sensor revealed good humidity-impedance characteristics with a wide range of relative humidity changes, decreasing $254k{\Omega}$ to $16k{\Omega}$ according to increase of relative humidity between 5% ~ 95% and the films were very stable on the Si wafer. These results reveal that $CN_x$ thin films can be used for Si based or HUSFET structure one chip micro-humidity sensors.

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The Effects of Micro-Environmental Factors on the House Dust Mite

  • Jo, Wan-Je;Sohn, Jang Yeul
    • Architectural research
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    • v.9 no.2
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    • pp.37-45
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    • 2007
  • The proliferation of the House Dust Mite(HDM) is affected by temperature, humidity, ventilation, etc. Measuring temperature and humidity was performed at the very location where dust samplings take place and where they live in reality together with temperature and humidity of the ambient of the room. There has been discussion over the key environment factor of HDM survival; absolute humidity or relative humidity. It seems that relative humidity is the more important determinant for the mite's survival through the analysis of previous studies. Temperature, humidity, ventilation rate and Der P1 were measured in 4 flats in London. Mite allergen was detected in every house. Levels of Der P1 varied between <100ng/g and 22,778ng/g. Flats with high relative humidity(>50%) and poor ventilation(<0.5ach) showed higher levels of mite allergen than flats with lower humidity and adequate air change rate. Questionnaire survey was conducted and the result helped to confirm the findings from monitoring of environmental factors and the dust sampling.

Humidity Variation by Green Space Calculation Method (녹지의 산출방법이 습도변화에 미치는 영향)

  • Yoon, Yong-Han;Park, Heon
    • Asian Journal of Turfgrass Science
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    • v.16 no.1
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    • pp.41-47
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    • 2002
  • For this study grasp quantitative humidity variation with planting stratification to various green space of calculation method, observed humidity distribution in the green space. with this data, coverage condition and humidity distribution, planting calculation method and humidity, planting stratification calculation method and humidity, analyzed by revolution analysis. In this result, as well as coverage condition, planting stratification effect humidity variation. increasing planting ratio (area) and planting volume (capacity) effect higher humidity. especially, if we compared between planting stratification calculation method and higher humidity, effect by a revolution coefficient and a correlation coefficient, effect relatively planting volume (capacity) higher than stratification ratio (area). today, in the index of higher humidity, planting calculation propose application of capacity method.

Theoretical and Experimental Considerations of Thermal Humidity Characteristics

  • Choi, Seok-Weon;Cho, Ju-Hyeong;Seo, Hee-Jun;Lee, Sang-Seol
    • International Journal of Aeronautical and Space Sciences
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    • v.3 no.1
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    • pp.9-18
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    • 2002
  • Thermal humidity characteristics were considered theoretically and experimentally. A Simply well-fitted correlation of a saturated vapor pressure-temperature curve of water was introduced based on Antoine equation to make theoretical prediction of relative humidity according to temperature variation. Characteristics of dew point were also examined theoretically and its relation with temperature and humidity was evaluated. The exact mass of water vapor in a specified humidity and temperature condition was estimated to provide useful insight into the idea about how much amount of water corresponds to a specified humidity and temperature condition in a confined system. A simple but well-fitting model of dehumidification process was introduced to anticipate the trend of relative humidity level during GN2(gaseous nitrogen) purge process in a humidity chamber. Well-suitedness of this model was also verified by comparison with experimental data. The overall appearance and specification of two thermal humidity chambers were introduced which were used to perform various thermal humidity tests in order to yield useful data necessary to support validity of theoretical models.