• 제목/요약/키워드: EVAPORATION

검색결과 3,553건 처리시간 0.03초

제한된 기상변수와 Polynomial Networks Approach를 이용한 일 증발접시 증발량의 모형화 (Modeling of Daily Pan Evaporation using the Limited Climatic Variables and Polynomial Networks Approach)

  • 김성원
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2010년도 학술발표회
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    • pp.1596-1599
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    • 2010
  • Group method of data handling neural networks model (GMDH-NNM) is used to estimate daily pan evaporation (PE) using limited climatic variables such as max temperature ($T_{max}$), min temperature ($T_{min}$), mean wind speed ($W_{mean}$), mean relative humidity ($RH_{mean}$) and sunshine duration (SD). And, for the performances of GMDH-NNM, it is composed of training and test performances, respectively. The training and test performances are carried out using daily time series data, respectively. From this research, we evaluate the impact of GMDH-NNM for the modeling of the nonlinear time series data. We should, thus, construct the credible data of the daily PE data using GMDH-NNM, and can suggest the methodology for the irrigation and drainage networks system. Furthermore, this research represents that the strong nonlinear relationship such as pan evaporation modeling can be generalized using GMDH-NNM.

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교반기법에 의한 준설매립토의 증발촉진에 관한 연구 (Desiccation Characteristics of Dredged Soft Clay by Ploughing Technique)

  • 정하익;오인규;지성현;이승원;이영남
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2002년도 봄 학술발표회 논문집
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    • pp.479-482
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    • 2002
  • The purpose of this paper is to present and discuss some of evaporation and desiccation observed in field experiments. Surface desiccation of dredged material is basically changed by evaporation characteristics which is controlled by weather and ploughing interval, etc. This study shows that ploughing interval is important factors in desiccation of dredged soft clay. A series of field experiments with variation of ploughing interval were carried out to get evaporation effiency and strength increase. In this study, it is proposed that ploughing technique on the total surface area expedites surface desiccation efficiency. Desiccation efficiency is improved when ploughing technique is applied on the surface area.

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Effect of Moisture Loss on Development of Distresses in Concrete Pavements

  • 정진훈
    • 콘크리트학회논문집
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    • 제17권4호
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    • pp.655-662
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    • 2005
  • Evaporation of concrete influences the development of both initial transverse cracking and delamination in the concrete slab. It was suggested that spatting distress might develop in the slab where the initial transverse cracking occurred by theoretical equations and a field investigation. Thus, efforts to prevent the evaporation of concrete using proper curing methods are required to minimize the distresses of the slabs. Effective curing thickness (ECT) concept was used in this paper to evaluate various curing methods used to prevent the evaporation from concrete. Curing effectiveness quantified by the ECT of different types and amounts of curing compound under various curing conditions was investigated based on the results of laboratory tests. According to the test results, the wind speed is inferred to be a significant factor of the magnitude and continuance duration of the curing effectiveness.

표면 거칠기에 따른 액적의 증발 냉각 (Evaporation Cooling of Droplet due to Surface Roughness)

  • 방창훈;권진순;예용택
    • 한국안전학회지
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    • 제18권3호
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    • pp.29-33
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    • 2003
  • The objective of the present work is to examine evaporation cooling of droplet due to surface roughness on a heated surface. The surface temperatures varied from 80-$160^{\circ}C$ on aluminum alloy (AL 2024) md surface roughness was 0.l8$\mu\textrm{m}$ 1.36$\mu\textrm{m}$. The results are as follows; Regardless of surface roughness, as droplet diameter is bigger, the in-depth temperature of solid decreases and evaporation time increases. In the case of same initial temperature on the heated surface, as droplet diameter is smaller and small surface roughness is bigger, evaporation time decreases and time averaged heat flux increases.

열 증발법에 의하여 제작된 ZnO 나노 구조의 형상에 미치는 산소 압력의 영향 (Effect of Oxygen Pressure on the Morphology of ZnO Nanostructures Fabricated by Thermal Evaporation Technique)

  • 이정헌;이근형
    • 한국전기전자재료학회논문지
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    • 제25권11호
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    • pp.873-877
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    • 2012
  • The effect of oxygen pressure in the synthesis of ZnO nanostructures through thermal evaporation of Zn powder was investigated. The thermal evaporation process was carried out in oxygen ambient for 1 hr at $1,000^{\circ}C$ under different pressures. The oxygen pressure was changed in range of 0.5 ~ 900 Torr. Any nanostructure was not formed on the specimens prepared at oxygen pressures lower than 10 Torr. When oxygen pressure was 100 Torr, ZnO nanowires were observed. With increasing the oxygen pressure to 500 Torr, the morphology of ZnO nanostructures changed from wire to tetrapod. For all the samples, room temperature photoluminescence spectra show a strong green emission peak at around 550 nm.

Effect of oxygen working pressure on morphology and luminescence properties of SnO2 micro/nanocrystals formed by thermal evaporation method

  • Kim, Min-Sung
    • Journal of Ceramic Processing Research
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    • 제19권5호
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    • pp.424-427
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    • 2018
  • The effect of oxygen pressure in the synthesis of $SnO_2$ micro/nanocrystals through thermal evaporation of Sn powder was investigated. The thermal evaporation process was performed at $1000^{\circ}C$ for 1 hr under various oxygen pressures. The pressure of oxygen changed from 10 to 500 Torr. The morphology of $SnO_2$ crystals changed drastically with oxygen pressure. $SnO_2$ nanoparticles with an average diameter of 120 nm were formed at oxygen pressure lower than 10 Torr. $SnO_2$ nanowires were grown under an oxygen pressure of 100 Torr. The nanowires have diameters in the range of 100 ~ 500 nm and lengths of several tens of micrometers. As increasing the oxygen pressure to 500 Torr, the sizes of wires increased. A strong visible emission peak centered at about 500 ~ 600 nm was observed in the room temperature cathodoluminescence spectra of all the products.