In this study, the performances of H2S, NH3, and HCl sensors for real-time monitoring in small emission facilities (4, 5 grades in Korea) were evaluated at high concentration conditions of those gases. And the proper approach for the collection of reliable measurement data by sensors was suggested through finding out the effect on sensor performances according to changes in temperature and humidity (relative humidity, RH) settings. In addition, an assessment on sensor data correction considering the effects produced by environmental settings was conducted. The effects were tested in four different conditions of temperature and humidity. The sensor performances (reproducibility, precision, lower detection limit (LDL), and linearity) were good for all three sensors. The intercept (ADC0) values for all three sensors were good for the changes of temperature and humidity conditions. The variation in the slope value of the NH3 sensor showed the highest value, and this was followed by the HCl, H2S sensors. The results of this study can be helpful for data collection by enabling the more reliable and precise measurements of concentrations measured by sensors.

Determination of explosion reference pressure is important in designing and testing flameproof enclosures (Ex d). Although relative humidity affects to explosion pressure, its effect is not well investigated for the gas group IIB, IIA, and I. This study tested explosion pressure for Ethylene (8 vol.%), Propane (4.6 vol.%), and Methane (9.8 vol.%), which are the representative gas of the gas group IIB, IIA, and I, at ambient temperature and atmospheric pressure (1 atm) under different relative humidity (0% ~ 80%). Ethylene- and Propane-air mixed gases generally tended to decrease as the relative humidity increased; however, explosion pressure was largely dropped at 20% of relative humidity compared to 0% and 10% of relative humidity. On the other hand, Methane-air mixture gas showed similar pressures at 0% and 10% of relative humidity; but no explosion occurred at more than 20%. The results of this study can be used in setting a testing protocol of explosion reference pressure for designing and testing a flameproof enclosure.

Low-cost particulate matter (PM) sensors based on the light scattering principle measure the concentration of particles by the change of scattering intensity after light is irradiated onto the particles. It has been reported that when the relative humidity is high, water vapor may cause the expansion of airborne particles and affect the accuracy of the light scattering method for PM measurement, but it has also been shown that the effect of humidity is not significant or even negligible. Therefore, to determine the effect of humidity on the Plantower PMS7003 light scattering sensor, in this study, a BAM1020 (Beta Attenuation Monitoring) was installed alongside to continuously monitor the ambient atmospheric PM concentration for approximately four weeks. The sensors collected data at 10-minute intervals, resulting in a 1-hour average for comparative analysis. To accurately measure humidity, the performance of the Arduino + DHT22 humidity sensor was also pre-evaluated using a series of saturated salt solutions. The humidity was grouped into five intervals and analyzed by visual analysis. The results confirmed that there was no significant correlation between PM2.5 differences and humidity, which were randomly and uniformly distributed around the mean. However, since in the very low and high concentration ranges based on the beta-ray monitor measurements, the difference between the light scattering sensor PM10 measurement and the reference value is much larger than the difference between the PM2.5 and the reference value., there is an additional need to investigate the appropriate correction method for dust season or PM10. The results show that the outcomes of the light scattering sensor are more influenced by particle size and concentration than by humidity.

To test a flameproof enclosure for the safety certificate, a reference pressure of explosion needs to be determined. However, the explosion pressure may be changed according to relative humidity of explosive gases. Therefore, the guideline on relative humidity should be recommended for measuring the explosion pressure for accurate and reproducible testings. This study examined the relationship of explosion pressure with relative humidity of hydrogen (31 vol %)-air and acetylene (14 vol %)-air mixture gases. The explosion pressures were measured by increasing the relative humidity of the gases by 10 % from dry state to 80 % in a cylindrical explosion enclosure of 2.3 L. on ambient temperature and atmospheric pressure (1 atm). The maximum explosive pressures were remained almost constant until the relative humidity reached 10 % for the hydrogen-air mixture and 20 % for the acetylene-air mixture. However, the maximum explosive pressures linearly decreased as the relative humidity increased. Based on the results of the study, it would be recommended to use 10 % relative humidity for the hydrogen-air mixture and 20 % for the acetylene-air mixture as the critical value in testing a flameproof enclosure.

This study was performed to investigate the effects of water molecules on ozone oxidation of acetaldehyde using a manganese oxide catalyst at room temperature. The catalytic ozone oxidation was conducted at different relative humidity (RH) conditions of 0%, 50%, and 80%. As the RH increased, both ozone and acetaldehyde removal efficiencies dropped due to competitive adsorption on the surface of the catalyst. At the highest RH of 80%, the oxidation reaction was severely retarded, and oxidation by-products such as acetic acid were formed and adsorbed on the surface. After the ozone oxidation of acetaldehyde, the regeneration of the catalyst using ozone alone was tested, and the further oxidation of accumulated organic compounds was investigated under the RH conditions of 0%, 50%, and 80%. When the highest relative humidity was introduced in the regeneration step, the ozonation reaction with the by-products adsorbed on the catalyst surface decreased due to the competitive reaction with water molecules. These findings revealed that, only when relative humidity was low to minimize the formation of by-products, the ozone oxidation of acetaldehyde using the manganese oxide catalyst at room temperature can be feasible as an effective control method.

해저 파이프라인 예비커미셔닝(Pre-commissioning) 단계는 입수(Flooding), 배수(Venting), 하이드로테스팅(Hydrotesting), 탈수 (Dewatering), 건조(Drying), 질소충진(N2 Purging)의 공정과정으로 구성된다. 이 중 건조와 질소충진 과정은 운용 중 파이프라인 내부에 하이 드레이트(Hydrate)의 발생과 가스 폭발의 위험을 방지하기 위해 상대습도를 이슬점 아래로 감소 및 유지되도록 규정되어 있다. 본 연구의 목적은 해저 파이프라인 예비커미셔닝 중, 공기건조(Air Drying)와 질소충진 공정과정에 대한 해석법을 개발하고 현장계측 결과와의 상호 비교를 통해 해석법의 활용가능성을 평가하는 데 있다. 해저 파이프라인 내부 상대습도 평가를 위한 방법으로 전산열유체(CFD)를 활용한 해석기법을 도입·적용하였고 해양공사 해저 파이프라인 공기건조와 질소충진 공정과정에 대한 현장계측 결과와 잘 일치함을 확인하였다. 개발된 공기건조와 질소충진 해석법 및 평가방법을 향후 해저 파이프라인 예비커미셔닝 작업의 사전 엔지니어링 도구로 활용할 경우, 작 업생산성 향상에 크게 기여할 것으로 사료된다.

본 연구는 다양한 상대습도(11~93%) 조건에서 해조류의 미생물 안정성 및 품질특성에 미치는 영향을 조사하였다. 미생물 안정성은 저장 중 대장균군, 일반세균, 효모 및 곰팡이수를 분석하였다. 일반세균은 상대습도 69~93%에서 4.40~7.00 log CFU/g, 효모 및 곰팡이는 4.20~6.40 log CFU/g로 상대습도 69%이상 조건에서 일반세균, 효모 및 곰팡이의 수가 급격하게 증가하였다. 고결현상은 상대습도 11~53% 조건에서는 일어나지 않았으나 69, 81, 93% 조건에서는 각각 86.9, 99.45, 99.98%로 높은 고결현상을 가지는 것으로 나타났다. 색도는 상대습도가 높아질수록 L값과 b값이 감소하였고, a값이 증가하여 갈변현상이 일어났다. 또한, 총 페놀함량(9.10~8.66 mg GAE/100 g dw), ABTS 소거능(24.20~24.18 mg AAE/100 g dw), FRAP(15.34~15.33 mg Fe(II)/100 g dw)활성은 저장 중 상대습도 11~33%에서 가장 높게 유지되었다. 그러나, 상대습도 43~93%에서 저장 중 총 페놀함량(8.66~4.00 mg GAE/100 g dw), ABTS(22.57~4.50 mg AAE/100 g dw), FRAP(13.06~4.00 mg AAE/100 g dw)활성이 감소하는 것으로 나타났다. 상대습도 81% 조건에서 ABTS 및 FRAP이 1/3배로 감소하였고, 93% 조건에서 총 페놀함량, ABTS 및 FRAP이 각각 1/2배, 1/5배, 1/3배로 감소하였다. 따라서, 일반세균, 효모 및 곰팡이의 성장 억제, 고결현상 방지, 갈변억제, 높은 총 페놀함량과 항산화활성 유지를 위해서는 상대습도 53% 이하의 조건에서 보관하는 것이 미생물 안정성 및 품질특성 유지에 효과적일 것으로 판단된다.

연구는 참외 재배 지에서 흰가루병, 담배가루이 및 두점박이응애가 동시에 발생하였을 때 45, 40, 35°C (대조구)의 온도에서 측창으로 환기 처리 시, 온실 내 온 ․ 습도의 변화, 병충해 발생과 잎말림, 그리고 개화조절에 미 치는 효과를 검토하였다. 3월 3일 ‘히든파워’ 대목에 접붙여진 ‘알찬꿀’ 참외를 40cm 간격으로 격리상에 심었고, 위 에 언급한 병해충이 모든 처리구에서 발생한 6월 18일부터 7월 13일까지 처리하였다. 온실의 온도는 맑은 날에는 설정 온도 지점까지 증가되었고, 45°C 환기 처리에서 고온 고습이 약 9시간 동안 유지되었다. 주간 최고 기온과 최 저 상대습도 차이는 45°C 환기 처리에서 가장 높았다. 환기 처리 11일 후에는 흰가루병과 두점박이응애 피해가 45°C 환기 처리에서 거의 회복되었지만 40°C와 35°C에서는 그렇지 않았다. 처리 14일 후, 담배가루이와 두점박이 응애 밀도는 45°C에서 유의하게 감소하였으나 흰가루병 증상은 유의하게 감소하지는 않았다. 잎말림은 고온에서 유발되었으나 45°C에서도 심하지 않았다. 처리 26일 후, 새로 나온 줄기의 15 마디의 개화수를 조사한 결과, 45°C에 서 암꽃이 전혀 나오지 않았고 수꽃은 1.2개로 나타났다. 이상의 결과는, 고온기에 45°C의 고온에서 2－3주간 환기 처리는 온실 내부의 고온 고습을 유도하여 흰가루병, 담배가루이, 두점박이응애를 통제하고, 개화를 억제하여 참외 의 영양 생장을 회복할 수 있는 방법으로 사료되었다.

The purpose of this study is to analyze the effect of temperature and humidity on the measured Particulate Matter (PM) concentrations recorded by PMS5003T, a low-cost light scattering type measuring tool. A regression analysis was performed on the ratio of PM concentrations measured by the light scattering method and the beta-ray absorption method according to temperature and humidity in an outdoor environment. As the temperature decreased, the PM concentration ratio increased, and this tendency intensified below 0oC. As the humidity increased, the PM concentration ratio increased, but the effect was less than the temperature effect. The coefficients of determination for temperature and humidity were R2 = 0.325 and 0.003, respectively, and the effects of temperature and humidity on the measured values w ere formulated and compensated for. As a result of the compensation, R2, relative precision, accuracy and RMSE improved from 0.927 to 0.958, from 91.183% to 96.651%, from 31.383% to 74.058%, and from 13.517 μg/m³ to 6.690 μg/m³, respectively. Finally, results from this study indicate that the reliability of the low-cost light scattering type PM sensor can be improved by applying the temperature and humidity compensation method.

In this study, a manganese catalyst on the surface of a ceramic support was developed for the removal of odor emitted from barbecuing restaurants. Its ozone oxidation at room temperature was tested using acetaldehyde (CH3CHO), the most dominant compound in the barbecuing odor, and the ozonation efficiency under wet conditions was also studied. The manganese catalyst was made with the honeycomb-type ceramic support, and an acid pretreatment was applied to increase its specific surface area, resulting in an increase of the degree of dispersion of manganese oxide. The acetaldehyde removal efficiency using the manganese catalyst on the acidpretreated support (Mn/APS) increased by 49%, and the ozone decomposition rate and the CO2 conversion rate also increased by 41% and 27%, respectively. The catalyst without surface pretreatment (Mn/S) showed a low efficiency for the acetaldehyde ozonation, and other organic compounds such as acetic acid (CH3COOH) and nonanal (CH3(CH3)7CHO) were found as oxidation by-products. In comparison, CO2 was the most dominant product by the ozonation of acetaldehyde using the Mn/APS. When the relative humidity was increased to 50% in the influent gas stream, the acetaldehyde removal efficiency using the Mn/APS decreased, but only the production rates of CO2 and acetic acid were changed. As a result, the manganese oxide catalyst on the surface of the acid-pretreated honeycomb support manifested high acetaldehyde ozonation even at humid and room temperature conditions.

The objectives of this study were (i) to evaluate the effects of temperature and relative humidity on two electrochemical sensors measuring hydrogen sulfide and ammonia using a laboratory testing system for various sensors, and (ii) to propose a calibration method for those concentrations to collect more reliable monitoring data. The effect of temperature and relative humidity was tested under three different conditions, respectively. The linearities measured data under all different conditions for the relative humidity and temperature were excellent, indicating more than 0.99 of R2 for both odor sensors. Under the condition of zero concentration, baselines (intercepts) at zero increased with increasing relative humidity for both hydrogen sulfide and ammonia sensors. The rate of gas concentration according to ADC variation (slopes) increased with increasing relative humidity about only the hydrogen sulfide sensor. In this study, slope, and intercept are utilized for calibration of hydrogen sulfide and ammonia concentration, and the reliability of the data of hydrogen sulfide and ammonia sensors is further enhanced by the relational expression obtained by this paper.

In this study, the humidity control effect of a counter-flow ventilator was analyzed in a greenhouse with high relative humidity at night in the winter season. A case of the counter-flow ventilator was 0.96 × 0.65× 0.82(W× D × H, m) and there were heat transfer element and two fans for air supply and exhaust in the counter-flow ventilator. Two counter-flow ventilators were used in this study and the setting humidity of the ventilators was 80%. The temperature and relative humidity at night(18:00-8:00) in the greenhouse were measured. In a greenhouse without a counter-flow ventilator, the average temperature and humidity was 14.9°C, 82.8%, respectively. When the counter-flow ventilator was operated, the corresponding averages were 15.1°C, 79.9%. The independent sample t test of monthly temperature and relative humidity showed no difference in temperature, and a significant difference in relative humidity with 1% of the significance level. Therefore, using the counter-flow ventilator helps to control relative humidity in greenhouse and increase yield.. And further research considering the pros and cons of using the counter-flow ventilator is needed.

본 연구에서는 딸기 재배온실의 최적 환경 구현에 필요한 시스템 선정을 위한 기초자료로 활용할 목적으로 딸기의 엽온을 측정하여 분석하였다. 그 결과는 다음과 같다. 실험 온실의 최대, 평균 및 최소 광투과율은 각각 64.9%, 58.3% 및 48.5%로 나타났다. 그리고 엽온은 재배시기나 처리구별 및 환기의 유무 등에 따라 다르게 나타나는 경향을 보였다. 실험기간 동안 상하 잎의 엽온과 기온의 편차는 –2.4∼3.7℃정도의 범위로 나타났다. 정식 직후에 엽온과 기온과의 차이가 3.7℃정도로써 가장 큰 차를 보였고, 생육이 왕성한 시기에도 전체적으로 엽온이 약간 높은 경향을 보이긴 하지만 엽온이 –2.4∼-2.3℃정도 낮은 경우도 있었다. 그리고 재배후기에는 엽온과 기온 간에는 거의 차이가 없는 것으로 나타났다. 엽온과 일사량 및 주변공기와 결정계수가 각각 0.4567 및 0.8826정도로써 일사량보다 엽온은 주변공기의 온도에 더 민감한 것을 알 수 있었다. 엽기온차와 옥외 수평면 일사량, 평균 및 최소 상대습도와의 상관관계가 거의 없는 것으로 나타났다.

절대 습도와 이슬점 온도의 관계에 대한 예비 교사들의 인식을 조사하기 위하여 설문지를 투입하였다. 설문 결과 예비 교사들이 “절대 습도와 이슬점 온도는 비례한다.”, “이슬점 온도는 공기 중의 수증기의 질량에 비례한다.”와 같은 견고한 오개념을 갖고 있음을 발견하였다. 예비 교사들이 갖는 이러한 오개념은 절대 습도와 이슬점 온도의 관계에 대한 7차 교육과정과 2007 개정 교육과정 중학교 과학 교과서의 부정확한 서술 내용에서 기인하는 것으로 사료된다. 한편, 2015 개정 교육과정 중학교 1학년 과학 교과서는 증발, 응결, 압력과 온도 변화에 따른 기체의 부피 변화를 분자 운동의 관점에서 다루기 때문에, 중학교 교육과정에서 이러한 관점을 유지하기 위해 수증기량과 이슬점 온도의 척도로서 수증기압의 도입은 예비 교사와 학습자의 오개념을 방지할 수 있으며, 과학 교육과정을 보다 일관되고 논리적으로 만들 수 있을 것으로 사료된다.

Odor emitted from food waste is commonly known as a severe problem, and needs to be controlled to minimize public complaints against food waste collection systems. In this study, ozone oxidation with manganese oxide catalyst, which is known to effectively treat odorous substances at room temperature, was applied to remove acetaldehyde and hydrogen sulfide, the model odorous compounds from food waste. In addition, the effect of relative humidity (RH) on the ozone/catalyst oxidation was tested at 40%, 60%, and 80%. When the catalyst was not applied, the removal of acetaldehyde was not observed with the ozone oxidation alone. In addition, hydrogen sulfide was slowly oxidized without a clear relationship under RH conditions. Meanwhile, the ozone oxidation rates for acetaldehyde and hydrogen sulfide substantially increased in the presence of the catalyst, but the removal efficiencies for both compounds decreased with increasing RH. Under the high RH conditions, active oxygen radicals, which were generated by ozone decomposition on the surface of the catalyst, were presumably absorbed and reacted with moisture, and the decomposition rate of the odorous compounds might be limited. Consequently, when the ozone oxidation device with a catalyst was applied to control odor from food waste, RH must be taken into account to determine the removal rates of target compounds. Moreover, its effect on the system performance must be carefully evaluated.