• Current Optics and Photonics
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• v.7 no.5
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• pp.504-510
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• 2023

An optical fiber dislocation fusion humidity sensor coated with graphene quantum dots is investigated. A Mach-Zehnder interferometer is fabricated with three dislocated single-mode fibers with graphene quantum dots coating humidity-sensitive materials. Humidity response experiments showed a good linear response and high sensitivity with easy fabrication and low-cost materials. From 22% to 98% RH, the humidity response sensitivity of the sensor is 0.24 dB/% RH, with 0.9825 linearity. To investigate the cross-response of humidity and temperature, temperature response experiments are conducted. From 30 ℃ to 70 ℃, the results showed 0.02 dB/℃ sensitivity and 0.9824 linearity. The humidity response experimental curve is compared with the temperature experimental curve. The big difference between humidity sensitivity and temperature sensitivity is very helpful to solve the cross-response of humidity and temperature. The influence of temperature fluctuations in humidity measurements is not obvious.

• Journal of Veterinary Science
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• v.25 no.3
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• pp.24.1-24.9
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• 2024

Importance: In veterinary forensic science, accurately determining the postmortem interval (PMI) is crucial for identifying the causes of animal deaths. Autolysis, a significant postmortem process, influences PMI estimation, but its relationship with humidity is not well understood. Objective: This study aimed to improve the accuracy of PMI estimates in veterinary forensic cases by looking into how different humidity levels affect autolysis in different organs of rats. Methods: The study involved 38 male rats, examining histopathological changes in their heart, liver, and pancreas. These organs were subjected to controlled humidity levels (20%, 55%, and 80%) at a constant 22℃. Tissue samples were collected at several intervals (0 h, 12 h, 24 h, 3 days, and 8 days) for comprehensive analysis. Results: Distinct autolytic characteristics in animal organs emerged under varying humidity conditions. The low-humidity environment rapidly activated autolysis more than the high-humidity environment. In addition, it was found that lower humidity caused nuclear pyknosis, cytoplasmic disintegration, and myofiber interruption. The liver, in particular, showed portal triad aggregation and hepatocyte individuation. The pancreas experienced cell fragmentation and an enlarged intracellular space. High humidity also caused the loss of striations in cardiac tissues, and the liver showed vacuolation. Under these conditions, the pancreas changed eosinophilic secretory granules. Conclusions and Relevance: The study successfully established a clear connection between the autolytic process in PMIs and relative humidity. These findings are significant for developing a more accurate and predictable method for PMI estimation in the field of veterinary forensic science.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.147-147
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• 2010

An electrolyte membranes for high temperature/low humidity is a demand for the proton exchange membrane fuel cells (PEMFCs). In this work, we prepared hybrid membranes, which have novel glass content in the hydrophilic and hydrophobic part of sulfonated poly(arylene ether sulfone) (SPAES) by in-situ sol-gel synthesis of various functional silane. The effect of silicate from functional silane content on the proton conductivity, water uptake of the hybrid membranes under high temperature and low humidity was quantitatively identified. The silicate content contributed to the enhancement of not only proton conductivity, but also water retention ability for PEMFCs operation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.1
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• pp.21-31
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• 1997

Toluene, n-hexane, and methyl ethyl ketone(MEK) were exposed to the activated carbon fiber(ACF) and 3M(Model 3500) diffusive samplers under low and high humidity levels. In order to evaluate these two samplers, the sampling capacity, sampling rate, reverse diffusion, and storage stability were obtained. At low humidity level($8{\pm}3%RH$), the adsorption amount of all three organic vapors to the ACF diffusive sampler showed a positive linear relationship up to 8 hours. However, at high humidity level($90{\pm}5%RH$), n-hexane and MEK maintained a positive linear relationship up to 1.5 hrs, but decreased in their adsorption amounts afterwards. On the other hand, the adsorption amount of n-hexane, MEK, and toluene to 3M diffusive sampler showed almost a positive linear relationship up to 8 hours at both humidity levels. At low humidity level, there was almost no reverse diffusion for both 3M and ACF diffusive samplers. However, when the ACF diffusive sampler was used at high humidity level, there was about 52.63% of MEK sample loss and about 92.59% of n-hexane sample loss. The storage stabilities of the ACF and 3M diffusive samplers were both relative stable except for MEK. In the case of MEK, the difference between the analysis of the organic vapor right after the sampling and that of 3 weeks later at room temperature was 45% for the ACF diffusive sampler and 18% for the 3M diffusive sampler. Since the storage stability of the samples stored in a refrigerator was relatively stable, they need to be refrigerated until the analysis is done.

• Journal of Biosystems Engineering
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• v.32 no.4
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• pp.247-255
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• 2007

During the winter season in Korea, the relative humidity of greenhouse at night often exceeds 90% because air temperature inside the greenhouse is usually controlled using a heater with all of windows closed to minimize heat loss, thereby requiring the use of a dehumidifier that can maintain optimum humidity levels of $70{\sim}80%$ to provide a good growth condition of crops. Also, such a high humid condition can cause the development of a pest, such as insects, fungi or diseases. However, the use of most conventional dehumidifiers for low temperature dehumidification is limited because their performance is degraded due to frost accumulation on the evaporator coil. This study was carried out to develop a refrigeratory-based dehumidifier suitable for low temperature dehumidification in greenhouse cultivation. The developed dehumidifier consists of a condenser and an evaporator installed separately so that relative and absolute humidity levels can be reduced when air passed through the condenser and evaporator, respectively. The prototype dehumidifier showed a dehumidification capacity of $5{\sim}7kg/h$ when air with a temperature of $15{\sim}25^{\circ}C$ and a relative humidity of $70{\sim}95%$ came into the dehumidifier. Under the condition that either temperature or relative humidity was fixed, the amount of condensed water was proportional to the levels of both temperature and relative humidity.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.9
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• pp.1210-1218
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• 2000

Four experiments were conducted to evaluate the effect of temperature and humidity on biochemical indices of Arbor Acres broilers at different weeks of age. The alkaline phosphatase (AKP), acid phosphatase (ACP), lactic dehydrogenase (LD), creatine kinase (CK), plasma glucose (Glu), calcium (Ca), potassium (K), chloride (Cl), urea nitrogen (UN), uric acid (UA), plasma thyroxin (T4), triiodothyronine (T3) and insulin levels were determined in all the four experiments. In experiment 1, the plasma Glu, LD and CK levels were increased by heat exposure ($35{^{\circ}C}$ and 35, 60, or 85% RH, 2 h) and this effect was aggravated by longer exposure (24 h). No significant changes (p>0.05) were found in Ca concentration, activity of AKP and ACP. In experiment 2, temperature (10, 20, 30, $33{^{\circ}C}$) had significant effect on the levels of K, Cl, UN, UA levels and the activity of LD (p<0.01), but had no significant influence on the activity of CK (p>0.05). The UN, UK and LD levels were elevated by low temperature $(10{^{\circ}C})$ (p<0.01), Cl content was increased by high temperature ($(33{^{\circ}C})$ (p<0.01), and K level was decreased by high ($(33{^{\circ}C})$ or low $(10{^{\circ}C})$ temperature and increased by medium temperature $(30{^{\circ}C})$ (p<0.01). The humidity (35, 85% RH) only had significant effect on Cl concentration which was decreased by high humidity (p<0.01). In experiment 3, the result showed that only the LD and CK activity were significantly increased (p<0.01) by high temperature (7, 24, 28, $32{^{\circ}C}$) or high humidity (35, 85% RH). Temperature and humidity had no significant effect on K, Cl, UA, UN and Glu levels (p>0.05). In experiment 4 (24, 27, 30, $33{^{\circ}C}$; 30, 45, 60, 75, 90% RH), plasma T3 level was declined by high temperature $(33{^{\circ}C})$, and this phenomena disappeared in birds under high temperature and high humidity environment. T4 concentration in plasma was not affected by temperature (p>0.05), but was increased by high or low humidity (p<0.01). Neither temperature nor humidity had significant effect on plasma insulin concentration (p>0.05). The results of the four experiments suggested that broilers at different growth periods might have different thermal requirements and would response differently to heat exposure. The plasma biochemical indices themselves had big variation; the reaction of the indices to thermal exposure treatment differed with the age of broilers. The big variation of biochemical indices themselves might cover the response of indices to temperature and humidity treatments.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.377-385
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• 2022

Surface morphology and adsorption characteristics of charcoals prepared from Korean traditional kiln were analyzed, and their moisture adsorption capacities were examined with respect to humidity and temperature change. Moisture adsorption capacities of red-clay powder, activated carbon fiber fabric (ACF fabric) and activated carbon fiber paper(ACF paper) were also examined to compare with those of charcoals. Moisture adsorption capacity of charcoal was low less than 45% humidity due to its hydrophobic property, but it slowly and linearly increased as increasing the humidity. Moisture adsorption capacity of red-clay powder was similar to charcoal at low level humidity, it increased exponentially as increasing the humidity showing Type V adsorption isotherm. Therefore, the weather forecast annal prepared by employee of weather centre in Joseon Dynasty is experimentally approved. ACF fabric and ACF paper show excellent moisture adsorption capacities, which can be used to humidity measuring sensor. Adsorption isotherm of charcoal slice was peculear showing the mixed Type I and Type IV due to low-pressure hysteresis that was occurred from embedment of nitrogen in crevice of charcoal. The specific surface area of charcoal increased by grinding charcoal slice to powder, resulted in increasing the desorption amount of adsorbent at low relative pressure.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.305-310
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• 2010

This study was carried out to investigate the effect of air humidity and water content of medium on the growth and physiological disorder of paprika in summer hydroponics. Treatments were composed of air humidity of control (over 90%) and dehumidification (low 90%) and water content of 80% and 50%. Time domain reflectometry (TDR) sensors and dehumidifier were used in a drip irrigation system and control system of air humidity, respectively. The early growth of paprika was not affected by air humidity but increased by high water content (80%) of medium. Mean fruit weight was reduced at high air humidity and low water content (50%) of medium, but the fruit number per plant and yield were increased at low air humidity. The incidence of brown fruit stem increased with increasing air humidity and water content of medium. Rate of blossom end rot increased in the low water content medium compared with the high water content medium. The nitrogen (N) was higher content in brown fruit stem than normal stem, but calcium (Ca) was lower.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.9
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• pp.77-86
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• 1998

A two-chip humidity sensor system has been developed which consists of a capacitive sense element die and a CMOS interface chip. The sense element was fabricated using thin polyimide films on (100) silicon substrate and showed excellent linearity(0.72%FS), low hysteresis (<3%) and low temperature coefficient(-0.0285 ~-0.0542pF/K) over a wide range of relative humidity and temperature. The capacitance-relative humidity characteristic exhibited a drift of 2~3% after 9 weeks of exposure to 4$0^{\circ}C$/90%RH. The signal-conditioning circuitry was fabricated using an 1.2- ${\mu}{\textrm}{m}$, one poly double metal CMOS process. The measured output voltage of the sensor system was directly proportional to relative humidity and showed good agreement with theory.

• Journal of Sensor Science and Technology
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• v.14 no.6
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• pp.395-401
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• 2005

A highly stable quartz crystal microbalance (QCM) that showed a stability of frequencies and exhibited a very low noise level has been developed. The long-term drift was <0.05 Hz/h over a period of 10 h, and the short-term rms (root mean square) noise was <0.015 Hz. Our QCM sensor was used as a humidity sensor employing a poly(methyl methacrylate) (PMMA) polymer film as a hygroscopic layer, which showed good characteristics in the relative humidity (RH) range of $2{\sim}90%$ RH. Comparing the characteristics of the QCM sensor with those of other types of humidity sensors employing PMMA film as a hygroscopic layer, and with other QCM sensors employing other hygroscopic layers is represented.