Konya’da Şehirleşmeye Bağlı Bağil Nem ve Su Buhari Basıncı Değişiklikleri (The Effects of Urbanization on Relative Humidity and Water Vapor Pressure in Konya)

2007 ◽  
Author(s):  
İhsan Çiçek ◽  
Necla Türkoğlu
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Vapor Pressure ◽  
Water Vapor Pressure

scholarly journals Water Vapor Pressure Deficit in Portugal and Implications for the Development of the Invasive African Citrus Psyllid Trioza erytreae

Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 229 ◽  
Author(s):  
Paulo Eduardo Branco Paiva ◽  
Tânia Cota ◽  
Luís Neto ◽  
Celestino Soares ◽  
José Carlos Tomás ◽  
...  
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Vapor Pressure ◽  
Vapor Pressure Deficit ◽  
Water Vapor Pressure ◽  
Control Measures ◽  
Effective Control ◽  
First Instar ◽  
Trioza Erytreae ◽  
Water Vapor Pressure Deficit

African citrus psyllid (Trioza erytreae (Del Guercio)) is a vector insect of the bacterium Candidatus Liberibacter africanus, the putative causal agent of Huanglongbing, the most devastating citrus disease in the world. The insect was found on the island of Madeira in 1994 and in mainland Portugal in 2015. Present in the north and center of the country, it is a threat to Algarve, the main citrus-producing region. Trioza erytreae eggs and first instar nymphs are sensitive to the combination of high temperatures and low relative humidity. Daily maximum air temperature and minimum relative humidity data from 18 weather stations were used to calculate the water vapor pressure deficit (vpd) from 2004 to 2018 at various locations. Based on the mean vpd and the number of unfavorable days (vpd < 34.5 and vpd < 56 mbar) of two time periods (February to May and June to September), less favorable zones for T. erytreae were identified. The zones with thermal and water conditions like those observed in the Castelo Branco and Portalegre (Center), Beja (Alentejo), Alte, and Norinha (Algarve) stations showed climatic restrictions to the development of eggs and first instar nymphs of African citrus psyllid. Effective control measures, such as the introduction and mass release of Tamarixia dryi (Waterson), a specific parasitoid, and chemical control are necessary in favorable periods for T. erytreae development, such as in spring and in areas with limited or no climate restrictions.

Regional relationship of water vapor pressure of human body surface

1963 ◽  
Vol 18 (5) ◽  
pp. 1019-1024 ◽  
Author(s):  
Kokichi Ohara ◽  
Takeo Ono
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Vapor Pressure ◽  
Water Vapor Pressure ◽  
Absolute Humidity ◽  
Skin Surface ◽  
The Body ◽  
Insensible Perspiration ◽  
Regional Relationship ◽  
Relationship Of

A new simple method for measurement of water discharge from the skin, as well as for estimation of absolute and relative humidity of the skin surface, was reported. The accuracy of the method was high with errors in the order of 2.5%. Estimations were made, using this method, at 108 points over the body of a young healthy nude male subject under neutral thermal conditions. Regional relationship of the rate of insensible perspiration, as well as the absolute and relative humidity of the skin surface, were obtained from the experiments. There was no difference between the regional relationship of the insensible perspiration and that of the absolute humidity. In the regions where perspiration rate is high, the water vapor pressure of the skin surface is also high. Sole, face, palm, and neck are the highest regions. Back of hands and gluteal region are the second highest zone. In distal parts of extremities, there exists an increasing gradient toward the palm or the sole. In the median region of the chest and epigastrium the values are somewhat higher though the chest and abdomen as a whole belong to the lowest regions. Distribution of the relative humidity showed no great difference in general from that of the perspiration rate or absolute humidity. It was found that the regional relationship is not perfectly symmetrical in both sides of the body. Submitted on January 16, 1963

scholarly journals Modeling the Response of Canopy Stomatal Conductance to Humidity

2009 ◽  
Vol 10 (2) ◽  
pp. 521-532 ◽  
Author(s):  
Shusen Wang ◽  
Yan Yang ◽  
Alexander P. Trishchenko ◽  
Alan G. Barr ◽  
T. A. Black ◽  
...  
Keyword(s):  
Water Vapor ◽  
Stomatal Conductance ◽  
Relative Humidity ◽  
Vapor Pressure ◽  
Power Function ◽  
Vapor Pressure Deficit ◽  
Water Vapor Pressure ◽  
Nonlinear Function ◽  
Environmental Variable ◽  
Water Vapor Pressure Deficit

Abstract Humidity of air is a key environmental variable in controlling the stomatal conductance (g) of plant leaves. The stomatal conductance–humidity relationships employed in the Ball–Woodrow–Berry (BWB) model and the Leuning model have been widely used in the last decade. Results of independent evaluations of the two models vary greatly. In this study, the authors develop a new diagnostic parameter that is based on canopy water vapor and CO2 fluxes to assess the response of canopy g to humidity. Using eddy-covariance flux measurements at three boreal forest sites in Canada, they critically examine the performance of the BWB and the Leuning models. The results show that the BWB model, which employs a linear relationship between g and relative humidity (hs), leads to large underestimates of g when the air is wet. The Leuning model, which employs a nonlinear function of water vapor pressure deficit (Ds), reduced this bias, but it still could not adequately capture the significant increase of g under the wet conditions. New models are proposed to improve the prediction of canopy g to humidity. The best performance was obtained by the model that employs a power function of Ds, followed by the model that employs a power function of relative humidity deficit (1 − hs). The results also indicate that models based on water vapor pressure deficit generally performed better than those based on relative humidity. This is consistent with the hypothesis that the stomatal aperture responds to leaf water loss because water vapor pressure deficit rather than relative humidity directly affects the transpiration rate of canopy leaves.

A Review on Water Vapor Pressure Model for Moisture Permeable Materials Subjected to Rapid Heating

2018 ◽  
Vol 70 (2) ◽  
Author(s):  
Liangbiao Chen ◽  
Jiang Zhou ◽  
Hsing-Wei Chu ◽  
Guoqi Zhang ◽  
Xuejun Fan
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Vapor Pressure ◽  
Sorption Isotherm ◽  
Rapid Heating ◽  
Water Vapor Pressure ◽  
Henry's Law ◽  
Moisture Condition ◽  
Henry’S Law ◽  
Nonlinear Sorption

This paper presents a comprehensive review and comparison of different theories and models for water vapor pressure under rapid heating in moisture permeable materials, such as polymers or polymer composites. Numerous studies have been conducted, predominately in microelectronics packaging community, to obtain the understanding of vapor pressure evolution during soldering reflow for encapsulated moisture. Henry's law-based models are introduced first. We have shown that various models can be unified to a general form of solution. Two key parameters are identified for determining vapor pressure: the initial relative humidity and the net heat of solution. For materials with nonlinear sorption isotherm, the analytical solutions for maximum vapor pressure are presented. The predicted vapor pressure, using either linear sorption isotherm (Henry's law) or nonlinear sorption isotherm, can be greater than the saturated water vapor pressure. Such an “unphysical” pressure solution needs to be further studied. The predicted maximum vapor pressure is proportional to the initial relative humidity, implying the history dependence. Furthermore, a micromechanics-based vapor pressure model is introduced, in which the vapor pressure depends on the state of moisture in voids. It is found that the maximum vapor pressure stays at the saturated vapor pressure provided that the moisture is in the mixed liquid/vapor phase in voids. And, the vapor pressure depends only on the current state of moisture condition. These results are contradictory to the model predictions with sorption isotherm theories. The capillary effects are taken into consideration for the vapor pressure model using micromechanics approach.

scholarly journals Surface Water Vapor Pressure and Temperature Trends in North America during 1948–2010

2012 ◽  
Vol 25 (10) ◽  
pp. 3599-3609 ◽  
Author(s):  
V. Isaac ◽  
W. A. van Wijngaarden
Keyword(s):  
United States ◽  
Water Vapor ◽  
North America ◽  
Relative Humidity ◽  
Vapor Pressure ◽  
Water Vapor Pressure ◽  
The United States ◽  
Specific Humidity ◽  
Canadian Prairies ◽  
Straight Line

Abstract Over one-quarter billion hourly values of temperature and relative humidity observed at 309 stations located across North America during 1948–2010 were studied. The water vapor pressure was determined and seasonal averages were computed. Data were first examined for inhomogeneities using a statistical test to determine whether the data were fit better to a straight line or a straight line plus an abrupt step, which may arise from changes in instruments and/or procedure. Trends were then found for data not having discontinuities. Statistically significant warming trends affecting the Midwestern United States, Canadian prairies, and the western Arctic are evident in winter and to a lesser extent in spring while statistically significant increases in water vapor pressure occur primarily in summer for some stations in the eastern half of the United States. The temperature (water vapor pressure) trends averaged over all stations were 0.30 (0.07), 0.24 (0.06), 0.13 (0.11), 0.11 (0.07) °C decade−1 (hPa decade−1) in the winter, spring, summer, and autumn seasons, respectively. The averages of these seasonal trends are 0.20°C decade−1 and 0.07 hPa decade−1, which correspond to a specific humidity increase of 0.04 g kg−1 decade−1 and a relative humidity reduction of 0.5% decade−1.

scholarly journals A New Principle for Measuring the Average Relative Humidity in Large Volumes of Non-Homogenous Gas

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5073 ◽  
Author(s):  
Lazik ◽  
de Rooij ◽  
Lazik ◽  
Meissner
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Vapor Pressure ◽  
Soil Water ◽  
Water Status ◽  
Water Vapor Pressure ◽  
Measurement Techniques ◽  
Direct Determination ◽  
Irrigated Agriculture ◽  
Soil Air

Due to the current extent of arid regions, the pressure on available water resources is increasing. A suitable measure for water availability and dynamics in dry soil is the relative humidity of the soil air. Due to the heterogeneity of soil, water inputs, and root water uptake, the humidity of soil air will vary in space. Therefore, area-representative measurement methods are needed to find a representative measure of the soil water status. Existing sensors for the direct determination of relative humidity only represent a single location with a spatial extent of up to several cm. We introduce a new measuring principle that averages over a spatially heterogeneously distributed relative humidity. It is based on the selective diffusion of water vapor pressure through a tubular semipermeable membrane to/from a closed measurement chamber. A measured pressure change is sensitive to the water vapor pressure and enables, without any external calibration, to estimate an average of the relative humidity. The comparison of our first laboratory prototype of the new sensor with calibrated reference sensors for relative humidity in a range of approx. 4 to 100% proves the linearity of the measuring method and its high accuracy. For further optimization improved reference measurement techniques are necessary. A potential application is the improvement of water use efficiency in irrigated agriculture.

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