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.

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.

증발기의 압력강하에 대한 상대습도의 영향

김창덕,강신형,박일환,이진호 대한설비공학회 2004 설비공학 논문집 Vol.16 No.5

It is well known that some key parameters, such as evaporating temperature, refrigerant mass flow rate, face velocity and inlet air temperature, have significant influence on the evaporator performance. However performance studies related to a humid environment have been very scarce. It is demonstrated that the refrigerant mass flow rate, heat flux, water condensing rate and air outlet temperature of the evaporator significantly increase with air inlet relative humidity. As the air inlet relative humidity increases, the latent and total heat transfer rates increase, but the sensible heat transfer rate decreases. The purpose of this study is to provide experimental data on the effect of air inlet relative humidity on the air and refrigerant side pressure drop characteristics for a slit fin-tube heat exchanger. Experiments were carried out under the conditions of inlet refrigerant saturation temperature of 7℃ and mass flux varied from 150 to 250 kg/m2s. The condition of air was dry bulb temperature of 27℃, air velocity varied from 0.38 to 1.6 m/s. Experiments showed that air velocity decreased 8.7% on 50% of relative humidity 40% of that at degree of superheat of 5℃, which resulted that pressure drop of air and refrigerant was decreased 20.8 and 8.3% for 50% of relative humidity as compared to 40%, respectively.

글리세린과 프로필렌 글리콜을 이용한 대기 중 수분의 흡습 효율 평가

김대현,호시모비 딜숏,송동하,박찬열,손윤석 한국냄새환경학회 2023 실내환경 및 냄새 학회지 Vol.22 No.3

This study was carried out to develop a system to reduce ultrafine dust using hygroscopic materials such as glycerin and propylene glycol. Prior to the development of an ultrafine dust reduction system, the moisture condensation efficiency of glycerin and propylene glycol was investigated based on relative humidity (RH). The results showed that when no substances (glycerin and propylene glycol) were added to a tedlar bag, the relative humidity and temperature remained constant. The moisture condensation efficiency of glycerin was 60%, and the time it took to reach 50% of the initial relative humidity was about 40minutes. In the case of propylene glycol, the moisture condensation efficiency was 75%, and the time it took to reach 50% of the initial relative humidity was about 10 minutes. When glycerin and propylene glycol mixture was added, the moisture condensation efficiency was 68% and it took 20 minutes to reach 50% of the initial relative humidity. These results suggest that hygroscopic materials such as glycerin and propylene glycol can actually condense moisture in the atmosphere. In addition, considering actual atmospheric conditions, the relative humidity was set to 60% and 40% or less, and the moisture condensation efficiency was measured. The results showed that the mixture of glycerin and propylene glycol yielded the highest condensation efficiencies, at 69% and 62%, respectively. Therefore, it is preferable to use a mixture of glycerin and propylene glycol to condense moisture in the range of relative humidity in the actual atmosphere.

RH-DMA를 적용한 PET 필름의 장기 점탄성 성능 예측

최순호,윤성호 한국복합재료학회 2019 Composites research Vol.32 No.6

A single frequency strain mode test, a stress relaxation mode test, and a creep test using RH-DMA were performed to investigate the effects of relative humidity and temperature on the viscous properties of PET film. The relative humidity was 10%, 30%, 50%, 70%, and 90%. The temperature was considered to be 30~95°C for single frequency strain mode tests, 30°C and 70°C for stress relaxation mode test, and 5~95°C for creep test. According to the results, higher relative humidity results in lower storage modulus and loss modulus, but the maximum value of the loss modulus is not significantly affected by changes in relative humidity and is almost constant. Relaxation modulus decreases rapidly at the beginning and becomes constant, and as the temperature increases, it is susceptible to changes in relative humidity. Strain recovery also increases rapidly at the beginning and is susceptible to changes in relative humidity as the temperature increases. In addition, as the temperature increases, the degree of increase in creep compliance increases, and as the temperature rises above the glass transfer temperature, the degree of increase becomes very large. The master curve determined by the time-temperature superposition provides the information to predict the long-term performance under operating conditions such as relative humidity and temperature. 상대습도와 온도가 PET 필름의 점탄성 특성에 미치는 영향을 조사하기 위해 RH-DMA를 이용하여 single frequency strain mode 시험, stress relaxation mode 시험, creep 시험을 수행하였다. 상대습도는 10%, 30%, 50%, 70%, 90%를 적용하고 온도는 single frequency strain mode 시험의 경우 30~95oC, stress relaxation mode 시험의 경우 30oC와 70oC, creep 시험의 경우 5~95oC를 고려하였다. 연구결과에 따르면 상대습도가 높아지면 저장탄성계수와 손실탄성계수는 낮아지며 손실탄성계수의 최대값은 상대습도의 변화에 큰 영향을 받지 않고 거의 일정해진다. 이완 탄성계수는 초기에 급격히 감소하다가 일정한 값을 가지며 높은 온도에서는 상대습도의 변화에 민감해진다. 변형률 회복는 초기에 급격히 증가하며 온도가 높아지면 이완 탄성계수와 마찬가지로 상대습도에 민감하게 변한다. 크리프 컴플라이언스의 증가 정도는 온도가 높아지면 커지며 유리전이온도보다 온도가 높아지면 증가 정도는 더욱 커진다. 시간-온도 중첩법을 통해 구해지는 마스터 선도를 이용하면 상대습도와 온도 등의 운용 조건에서의 장기 성능을 예측할 수 있는 정보를 얻을 수 있다.

상대습도에 따른 비정질 규산염 나노입자의 함수량 정량 분석을 위한 ¹H 고상 핵자기 공명 분광분석 방법론 연구

오솔비 ( Sol Bi Oh ),김현나 ( Hyun Na Kim ) 한국암석학회·(사)한국광물학회 2021 광물과 암석 (J.Miner.Soc.Korea) Vol.34 No.1

명목상의 무수 광물의 수소 원자는 격자의 결함에 존재하는 것으로 알려져 있지만, 나노 스케일 입자의 경우 입자 표면에 물과 수산기의 형태로 존재할 수 있다. 본 연구에서는 비정질 규산염 나노입자의 수소 원자 환경에 대한 정량 측정 방법으로서, ¹H 고상 핵자기 공명(solid-state nuclear magnetic resonance, NMR) 분광분석의 실효성을 알아보고자 하였다. 온도와 습도가 조절되는 글러브 박스 내에서 NMR 로터에 패킹된 비정질 규산염 나노입자를 25%와 70% 상대습도에서 2일에서 10일까지 동안 보관한 후 ¹H NMR 스펙트럼을 측정한 결과, 약간의 차이는 있었으나 큰 변화가 관찰되지 않았다. 이는 NMR 로터에 패킹된 시료의 수소 원자 환경이 외부 대기에 의해 거의 변화하지 않았음을 의미한다. 수화 시간에 따른 비정질 규산염 나노입자의 함수량은 약 10% 범위에서 차이를 보이며, 이는 글러브 박스의 시간적, 공간적 습도 불균일성에 의한 것으로 생각된다. ¹H NMR 스펙트럼의 정량 분석 결과, 수화 상대습도가 증가함에 따라 비정질 규산염 나노입자의 수소 원자 수 역시 선형적으로 증가하였다. 이와 같은 결과는 NMR 로터의 시료 밀폐 능력이 수화 환경을 보존하며, 대기 상대습도 변화에 따른 나노입자의 함수량 변화 측정에 적합함을 의미한다. 본 연구의 결과를 통해, ¹H 고상 핵자기 공명 분광분석을 이용하여 나노 스케일의 명목상의 무수 광물의 표면적, 결정도가 습도에 따른 광물의 함수량 변화에 미치는 영향에 대한 체계적인 연구를 할 수 있을 것으로 기대된다. The hydrogen in nominally anhydrous mineral is known to be associated with lattice defects, but it also can exist in the form of water and hydroxyl groups on the large surface of the nanoscale particles. In this study, we investigate the effectiveness of ¹H solid-state nuclear magnetic resonance (NMR) spectroscopy as a robust experimental method to quantify the hydrogen atomic environments of amorphous silica nanoparticles with varying relative humidity. Amorphous silica nanoparticles were packed into NMR rotors in a temperature-humidity controlled glove box, then stored in different atmospheric conditions with 25% and 70% relative humidity for 2~10 days until ¹H NMR experiments, and a slight difference was observed in ¹H NMR spectra. These results indicate that amount of hydrous species in the sample packed in the NMR rotor is rarely changed by the external atmosphere. The amount of hydrogen atom, especially the amount of physisorbed water may vary in the range of ~10% due to the temporal and spatial inhomogeneity of relative humidity in the glove box. The quantitative analysis of ¹H NMR spectra shows that the amount of hydrogen atom in amorphous silica nanoparticles linearly increases as the relative humidity increases. These results imply that the sample sealing capability of the NMR rotor is sufficient to preserve the hydrous environments of samples, and is suitable for the quantitative measurement of water content of ultrafine nominally anhydrous minerals depending on the atmospheric relative humidity. We expect that ¹H solid-state NMR method is suitable to investigate systematically the effect of surface area and crystallinity on the water content of diverse nano-sized nominally anhydrous minerals with varying relative humidity.

Artificial neural networks approach for forecasting of monthly relative humidity in Sivas, Turkey

Cahit Gurlek 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8

Relative humidity is a crucial parameter for various agricultural and engineering applications and atmospheric dynamics; hence its accurate and reliable estimation is essential. This study aims to predict monthly relative humidity by means of the artificial neural networks (ANNs) method using neighbouring data in Sivas Province, Turkey. Nineteen years (2000-2018) monthly mean relative humidity data of five measurement stations was used for ANN analysis. The prediction accuracy of the ANN models was evaluated with the coefficient of determination (R 2 ), mean absolute error (MAE), mean absolute percentage error (MAPE) and root mean squared error (RMSE). Contour plot maps were also generated for visual comparison. R 2 , MAE, MAPE and RMSE values ranged between 0.952-0.965, 1.916-2.586, 3.422-4.974 and 2.472-3.391, respectively. The results showed that the ANN method provided satisfactory predictions for relative humidity.

녹지조건에 따른 상대습도의 변화

윤용한,송태갑 建國大學校 自然科學硏究所 2002 建國自然科學硏究誌 Vol.13 No.2

This reseach sought to measure the relative humidity in the green belt on clear days aimed at indentifying the relevancy of relative humidity with landcover status and the height of forest. Based on this measurement data, it used regresssion analysis and interpreted the relevancy of the relative humdity in the green belt with the landcover ratio and with the height of woody plants. As a result, high wet areas are formed in the forest land and near the water surface, while low wet areas are formed on the paved surface and bare ground. Taking a look at the relevancy between the landcover ratio and the relative humidity, the increase in forestland and grassland is ??ective in raising the relative humidity. Also, the increase in number of trees, regarless of the height of trees, is effective in raising the relative humdity, and the efficiency is big in the order of arbores and small arbores.

Feasibility study of environmental relative humidity through the thermodynamic effects on the performance of natural gas liquefaction process

Qyyum, Muhammad Abdul,Minh, Le Quang,Ali, Wahid,Hussain, Arif,Bahadori, Alireza,Lee, Moonyong Elsevier 2018 Applied thermal engineering Vol.128 No.-

<P><B>Abstract</B></P> <P>This study examined the thermodynamic effects of relative humidity (RH) on the performance of the natural gas liquefaction process. A single mixed refrigerant (SMR) liquefaction process was chosen for this study because of its simplicity and compactness. In addition, it is considered the most promising process for the liquefied natural gas (LNG) floating production, storage and offloading (FPSO) unit. The SMR process was optimized using a modified coordinate descent methodology, which resulted in 13.6% energy savings. Subsequently, an interface between commercial software Aspen Hysys® and MS-Excel VBA was carried out to study the effects of RH. The results showed that RH has pronounced effects on the performance of the LNG cycle by affecting the enthalpy balance around the air coolers, which ultimately affects the overall compression power, LNG exchanger performance, and other design and operational parameters. Furthermore, when the RH was increased from 0% to 95%, the UA value (product of overall heat transfer coefficient and heat transfer area) of the air coolers and the overall compression power decreased and increased linearly, respectively. Moreover, the heat transfer coefficient of the LNG cryogenic exchanger increased asa 4th order polynomial function in terms of the log-mean enthalpy difference. The results can provide insight into the selection of the appropriate design and operational parameters for the LNG plants associated with the regions of low or high relative humidity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effects of relative humidity on the performance of SMR was investigated successfully. </LI> <LI> Compression energy for SMR process was reduced significantly. </LI> <LI> Compression power has a linear relation with the relative humidity. </LI> <LI> The UA value of LNG cryogenic exchanger increases as 4th-order polynomial function. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

IoT 기반 기온, 상대습도, 강수 탐지 관측 품질평가 - 2020년 여름 서울을 중심으로 -

오석근,손석우,김선영,박준상,이종원 건국대학교 기후연구소 2021 기후연구 Vol.16 No.3

This study evaluates the quality of surface air temperature, relative humidity, and precipitation detection observed by 22 internet of thing (IoT)-based mini-weather stations in Seoul in 2020 summer. The automatic weather station (AWS) closest to each IoT-based station is used as reference. The IoT-based observations show surface air temperature and relative humidity are about 0.2-4.0°C higher and about -1--22% lower than the AWS observations, respectively. However, they exhibit temporal variability similar to the AWS observations on both diurnal and daily time scales, with daily correlations greater than 0.90 for temperature and 0.82 for relative humidity. Given these strong linear relationships, it show that temperature and relative humidity biases can be effectively corrected by applying a simple bias correction method. For IoT-based precipitation detection, we found that precipitation conductivity value (PCV) during precipitation events is well separated from that during non-precipitation events, providing a basis for distinguishing precipitation events from non-precipitation events. When the PCV threshold is set to 250 for precipitation detection, the highest critical success index and the bias score index close to one, suitable for operational precipitation detection, are obtained. These results demonstrate that IoT-based mini-weather stations can successfully measure surface air temperature, relative humidity, and precipitation detection with appropriate bias corrections.