• Title/Summary/Keyword: humid

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Biomass Structure and Dry Matter Dynamics in a Fire Influencing Montane Subtropical Humid Grassland, Western Ghats Southern India

  • Paulsamy, S;Manian, S.;Udaiyan, K.;Arumugasamy, K.;Nagarajan, N.;Kil, B.S.
    • The Korean Journal of Ecology
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    • v.24 no.4
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    • pp.227-232
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    • 2001
  • The biomass structure for three major components viz., the dominant grass, Chrysopogon zeylanicus Thw., the 'other grasses' and the'remaining species'and dry matter dynamics for total community were studied over a period of one year in an annual fire influenced subtropical humid grassland community in Western Ghats, India. The biomass of aboveground, belowground and litter compartments were high as in other humid grasslands and generally have positive correlation with rainfall, rainy days and relative humidity with the exception of litter parts. The above and belowground net primary productions (4,561 and 722 g/㎡, respectively) were also higher and were comparable with other humid tropical grasslands. The turnover of organic matter was rapid, Of the total input of 14.47 g/㎡ into the system, about 86.3% was allocated to above ground parts and 13.7% to below ground parts. The total disappearance was 2.56 g/㎡ and it was accounted to be 17.68% of the total output. The net surplus of dry matter (82.32%) in the post fire community indicates that the grassland was maintained in a seral stage. Hence it is suggested that prescribed burning may keep this ecosystem in a highly productive and seral stage.

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Should Workers Avoid Consumption of Chilled Fluids in a Hot and Humid Climate?

  • Brearley, Matt B.
    • Safety and Health at Work
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    • v.8 no.4
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    • pp.327-328
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    • 2017
  • Despite provision of drinking water as the most common method of occupational heat stress prevention, there remains confusion in hydration messaging to workers. During work site interactions in a hot and humid climate, workers commonly report being informed to consume tepid fluids to accelerate rehydration. When questioned on the evidence supporting such advice, workers typically cite that fluid absorption is delayed by ingestion of chilled beverages. Presumably, delayed absorption would be a product of fluid delivery from the gut to the intestines, otherwise known as gastric emptying. Regulation of gastric emptying is multifactorial, with gastric volume and beverage energy density the primary factors. If gastric emptying is temperature dependent, the impact of cooling is modest in both magnitude and duration (${\leq}5$ minutes) due to the warming of fluids upon ingestion, particularly where workers have elevated core temperature. Given that chilled beverages are most preferred by workers, and result in greater consumption than warm fluids during and following physical activity, the resultant increased consumption of chilled fluids would promote gastric emptying through superior gastric volume. Hence, advising workers to avoid cool/cold fluids during rehydration appears to be a misinterpretation of the research. More appropriate messaging to workers would include the thermal benefits of cool/cold fluid consumption in hot and humid conditions, thereby promoting autonomy to trial chilled beverages and determine personal preference. In doing so, temperature-based palatability would be maximized and increase the likelihood of workers maintaining or restoring hydration status during and after their work shift.

Effects of Relative Humidity and Fiber Properties on the Moisture Permeability of Multilayer Fabric Systems (환경 및 섬유 특성이 멀티레이어 직물시스템의 투습성에 미치는 영향)

  • Suhyun Lee;Sohyun Park
    • Fashion & Textile Research Journal
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    • v.25 no.1
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    • pp.119-126
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    • 2023
  • This study aimed to determine the effects of relative humidity and fiber properties on the moisture permeability of multilayer systems by measuring water vapor transmission in the overlapping condition of various fabrics. The results confirmed that the property of the fabric in contact with the humid environment affects the moisture permeability. If the layer facing the humid environment is hydrophobic and the layer facing the dry environment is superhydrophobic, water vapor transmission increases by up to 17.8% compared to the opposite conditions. Comparing the correction values of the water vapor transmission reflecting the thickness of the specimen under the multilayer condition showed that permeability was higher when the hydrophilic or hydrophobic layer was facing the humid environment. The opposite was true from the "push-pull" effect of absorption mechanism. In the case of moisture permeability, the more hydrophilic the surface facing the humid environment, the more permeable that water vapor diffuses and passes through. It was concluded that the "pull-push" effect, in which water vapor diffuses widely through the hydrophilic facing a humid environment and then passes through the hydrophobic layer, contributes to the improvement of permeability. Permeability differed according to the multilayer overlapping condition. When the relative humidity was high, the "pull-push" effect was insignificant. This is caused by water droplets absorption after the partial migration of water due to condensation. These results suggest that the overlapping conditions and properties of fabrics should vary depending on heavy sweating or not.

A Study of Concrete with Large Quantity of Fly-Ash (플라이애쉬 다량 함유 콘크리트에 관한 실험적 연구)

  • 이동하;공민호;백민수;김성식;이영도;정상진
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.1219-1224
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    • 2001
  • In this study, concrete what plenty of fly ash used as binder is left in three condition humid condition($35^{\circ}C$), normal condition($20^{\circ}C$) and cold condition($5^{\circ}C$). Fly ash concrete is tested in fresh properties and early strength. The result of tests could give the decisive factor of form side's stripping time. The purpose of this study is presenting the stripping time data to help the construction work. The result of this study is below. 1. The plain concrete specimen in humid condition developed high strength before 5 days, then strength development is declined. 10 day strength of plain specimen is smaller than the normal condition specimen's. 2. The strength of the concrete which plenty of fly ash used is more developed than the concrete in normal condition. It says that fly ash concrete is useful in the humid condition. 3. As fly ash substitution rate is downsizing and outdoor temperature degree is low, form stripping times is getting shorter.

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A Study on Humid Control Characteristics of Alkaline Desiccants (알칼리성 용해제의 조습특성에 관한 연구)

  • Hong, Young-Ho
    • Applied Chemistry for Engineering
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    • v.21 no.2
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    • pp.169-173
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    • 2010
  • Many salts have the ability to attract and remove water vapor from the surrounding environment. The ability of each salt to remove water vapor is based on the flow rate and temperature of air in surrounding. The objective of this study was toinvestigate the humid control characteristics in air-water system by using a desiccants. The aim is to asses the influence of three parameters on the humid control process which are air volume rate, air temperature and desiccant amount. Humidity control materials which consist of K (potassium) or Na (sodium) have been synthesized by the aqueous process. The humidity control properties of materials have been also investigated. Experiment results are as following. Thermal characteristics of desiccants showed similar properties regardless of processing condition. The experiments were examined by using artificial air-water system (humidity : 70~93%, air volume rate : $0.22{\sim}0.69m^3/s$). The results showed that the Na-type desiccant was an effective material. It was found that dew point increased with air volume rate, and the humidity change in humid control process was depended on desiccants amount.

Effects of Humidity and Velocity on Frost Distribution Characteristics of Humid Air Flow on Cold Surfaces (차가운 표면위에서의 습공기 유동의 습도 및 속도가 착상분포 특성에 미치는 영향)

  • Kwon Jeong-Tae;Rew Keun-Ho;Lim Hyo-Jae;Han Ji-Won;Kwon Young Chul
    • Journal of Energy Engineering
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    • v.14 no.4 s.44
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    • pp.213-218
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    • 2005
  • In order to understand the heat and mass transfer characteristics of humid airflow in frosting conditions, a flat plate of aluminum with cooling modules located in the central part of the plate was used. A microscope system (resolution of 0.05 mm) was used for the measurement of local thickness of frost at seven points along the plate in the flow direction. For the total mass of frost at each test operation, an electronic balance (resolution of 1 mg) was used. The local frost thickness distributions far various test conditions were presented along with the frost mass data measured at the given operating times. The effect of humidity and velocity of humid air on frosting were analyzed.

An Experimental Study on Frosting of Humid Air-flow on a Surface with Local Cooling for Heat Exchanger Design (열교환기 설계를 위한 국소 냉각 표면위에서의 습공기 유동의 착상실험)

  • Kwon, Jeong-Tae;Lim, Hyo-Jae;Park, Kyoung-Woo;Kim, Chang-Eob;Kim, Kyung-Min;Kwon, Young-Chul
    • Journal of Energy Engineering
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    • v.17 no.1
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    • pp.1-7
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    • 2008
  • The present study has been conducted to understand the heat and mass transfer characteristics of humid airflow in frosting conditions. A flat plate of aluminum was used for the simulation of flat surface part of the fin of the heat exchanger. The aluminum surface temperatures were measured and analyzed to clarify the heat and mass transfer characteristics under frosting conditions. Also, the pressure drops were measured to clarify the air-blocking effect of frost in the mini channel of the air-side hoot exchangers. A data reduction method was developed far the analysis of local characteristics of humid air under frosting conditions.

Changes in Sugars Composition of Dried Lavers during Storage (마른김의 당류조성(糖類組成)과 저장중의 변화)

  • Park, Young-Ho
    • Korean Journal of Food Science and Technology
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    • v.5 no.4
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    • pp.235-239
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    • 1973
  • Studies were made on the sugars composition in dried lavers (Porphyra yezoensis Ueda) and changes in the contents of sugars during the storage under a dry and a humid conditions respectively. 1) No notable difference was observed in the glucose content between those dried lavers samples, which were stored under dry and humid conditions. Galactose content showed little change under a dry condition, but under a humid condition rapidly increased to a maximum of about ten times of its initial amount and then decreased gradually. 2) The content of floridoside rapidly decreased under a humid condition while slowly decreased under a dry condition, of which tendency is a contrast to that of galactose. 3) One of the unidentified components, which is deduced to be isofloridoside, showed a fluctuation pattern, which bears resemblance to that of floridoside.

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Suggestion of Method to Classify Moisture or Dryness Condition from Moisture Index Obtained by NDVI (NDVI를 이용한 습윤지표를 기준으로 습윤 및 건조상황의 분류 방법 제안)

  • Kim, Joo-Cheol;Shin, Sha-Chul;Lee, Sang-Jin;Hwang, Man-Ha
    • Journal of the Korean Association of Geographic Information Studies
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    • v.12 no.4
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    • pp.84-94
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    • 2009
  • Moisture Index time series derived from NOAA/AVHRR data have showed to be useful for humid and arid states. The humid/arid states of the Geum river basin are classified by means of the moisture index estimated from the climatic water budget model. Validations showed that the moisture index has excellent ability to detect humid/arid conditions and to measure time of its onset, intensity and duration. In this study, a simple method to classify the moisture index is proposed by statistical distribution condition. Also, the moisture index is compared with the regional actual state to detect drought area.

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Study of the Holocene Climate Change Using Soil Organic Carbon in Gwangju Area, Southwest Part of Korea (토양유기탄소분석을 통한 광주지역의 홀로세 기후환경변화 연구)

  • Jung, Heakyung;Kim, Cheong Bin
    • Journal of The Geomorphological Association of Korea
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    • v.23 no.2
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    • pp.83-93
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    • 2016
  • Using a Quaternary sediment sampled from the Gwnahju-cheon various organic carbon analysis have been accomplished. The result helped us to figure out how climate environment has changed through at that time. The analysis outcome, except the analysis of upper section(range of 0 to 50 cm depth), showed that the climate was generally warm and humid at that time. However, even in this result, the climate environment was slight differences, it can be divided into four periods. Period I is from $3,880{\pm}30yr\;BP$ to $3,030{\pm}70yr\;BP$, in which the climate was relatively warm and humid/dry slightly. Period II is from $3,030{\pm}70yr\;BP$ to $2,970{\pm}70yr\;BP$, in which the climate was relatively warmer than period I and the most humid among all period. Period III is from $2,970{\pm}30yr\;BP$ to $2,270{\pm}70yr\;BP$ and refers to the warmest among all periods and also relatively drier/more humid than period I. Period IV which is from $2,270{\pm}70yr\;BP$ to $2,170{\pm}110yr\;BP$ represents the coolest and driest climate compare to other periods, although there is a high possibility of disturbance caused by cultivation activities.