scholarly journals Calculation of Steady-State Evaporation for an Arbitrary Matric Potential at Bare Ground Surface

Water ◽  
2017 ◽  
Vol 9 (10) ◽  
pp. 729 ◽  
Author(s):  
◽  
Keyword(s):  
Steady State ◽  
Ground Surface ◽  
Bare Ground ◽  
Matric Potential

Bare-ground surface heat and water exchanges under dry conditions: Observations and parameterization

1993 ◽  
Vol 66 (1-2) ◽  
pp. 173-200 ◽  
Author(s):  
I. Braud ◽  
J. Noilhan ◽  
P. Bessemoulin ◽  
P. Mascart ◽  
R. Haverkamp ◽  
...  
Keyword(s):  
Ground Surface ◽  
Surface Heat ◽  
Bare Ground ◽  
Dry Conditions

scholarly journals A dynamic physical model for soil temperature and water in Taylor Valley, Antarctica

2010 ◽  
Vol 22 (4) ◽  
pp. 419-434 ◽  
Author(s):  
H.W. Hunt ◽  
A.G. Fountain ◽  
P.T. Doran ◽  
H. Basagic
Keyword(s):  
Steady State ◽  
Soil Temperature ◽  
Soil Water ◽  
Capillary Flow ◽  
Temporal Trends ◽  
Soil Layer ◽  
Ground Surface ◽  
Longwave Radiation ◽  
Saturated Soil ◽  
Water Vapour Concentration

AbstractWe developed a simulation model for terrestrial sites including sensible heat exchange between the atmosphere and ground surface, inter- and intra-layer heat conduction by rock and soil, and shortwave and longwave radiation. Water fluxes included snowmelt, freezing/thawing of soil water, soil capillary flow, and vapour flows among atmosphere, soil, and snow. The model accounted for 96–99% of variation in soil temperature data. No long-term temporal trends in soil temperature were apparent. Soil water vapour concentration in thawed surface soil in summer often was higher than in frozen deeper soils, leading to downward vapour fluxes. Katabatic winds caused a reversal of the usual winter pattern of upward vapour fluxes. The model exhibited a steady state depth distribution of soil water due to vapour flows and in the absence of capillary flows below the top 0.5 cm soil layer. Beginning with a completely saturated soil profile, soil water was lost rapidly, and within a few hundred years approached a steady state characterized by dry soil (< 0.5% gravimetric) down to one metre depth and saturated soil below that. In contrast, it took 42 000 years to approach steady state beginning from a completely dry initial condition.

scholarly journals Deposition of dinitrogen pentoxide, N<sub>2</sub>O<sub>5</sub>, to the snowpack at high latitudes

2010 ◽  
Vol 10 (11) ◽  
pp. 25329-25354 ◽  
Author(s):  
D. M. Huff ◽  
P. L. Joyce ◽  
G. J. Fochesatto ◽  
W. R. Simpson
Keyword(s):  
Steady State ◽  
Gradient Method ◽  
Loss Rate ◽  
Deposition Velocity ◽  
Ground Surface ◽  
High Latitudes ◽  
Field Campaign ◽  
Dinitrogen Pentoxide ◽  
Knowledge Based ◽  
Winter Conditions

Abstract. Dinitrogen pentoxide, N2O5, is an important nighttime intermediate in oxidation of NOx that is hydrolysed on surfaces. We conducted a field campaign in Fairbanks, Alaska during November, 2009 to measure the flux (and deposition velocity) of N2O5 depositing to snowpack using the aerodynamic gradient method. The deposition velocity of N2O5 under Arctic winter conditions was found to be 0.59 ± 0.47 cm/s, which is the first measurement of this parameter to our knowledge. Based on the measured deposition velocity, we compared the chemical loss rate of N2O5 via snowpack deposition to the total steady state loss rate and found that deposition to snowpack is a significant fraction of the total chemical removal of N2O5 measured within a few meters of the ground surface.

scholarly journals Thermal environment mitigation effects in suburban area

2019 ◽  
Vol 111 ◽  
pp. 06041
Author(s):  
Yoshihito Kurazumi ◽  
Emi Kondo ◽  
Kenta Fukagawa ◽  
Yoshiaki Yamato ◽  
Kunihito Tobita ◽  
...  
Keyword(s):  
Human Body ◽  
Thermal Environment ◽  
Ground Surface ◽  
Outdoor Environment ◽  
Psychological Responses ◽  
Bare Ground ◽  
Indoor Space ◽  
Green Areas ◽  
Outdoor Space ◽  
The Relationship

The purpose of this paper is to clarify the relationship between the physiological and psychological responses of the human body and the outdoor environment evaluation index ETFe (enhanced conductioncorrected modified effective temperature). The experiments were carried out in summer. For the measurements, observation points were selected with consideration for the condition of the ground surface such as bare ground where the surface is gravel or soil; paved ground such as concrete, asphalt or blocks; green areas covered in plants and water surfaces and with consideration for the condition of the sky factor due to buildings or trees. 19 observation points were chosen. Subjects were 38 healthy young. ETFe that was considered to report neither hot nor cold, thermally neutral sensation, was 30.6°C. ETFe that was considered to report neither comfortable nor uncomfortable comfort was 35.5°C. It was considered that the threshold for the human body with regards to thermal environment stimuli in an outdoor space is higher than the thermal environment stimuli in a summer indoor space.

The Dynamic Behavior of Surface Grinding: Part 1—A Mathematical Treatment of Surface Grinding

1971 ◽  
Vol 93 (2) ◽  
pp. 485-491 ◽  
Author(s):  
R. A. Thompson
Keyword(s):  
Steady State ◽  
Dynamic Behavior ◽  
Ground Surface ◽  
Steady State Solution ◽  
Surface Grinding ◽  
Mathematical Representation ◽  
Mathematical Treatment ◽  
Test Results ◽  
Wheel Wear ◽  
Insight Into

A mathematical representation for surface grinding is developed. The main feature of the model is that it takes into account the reversing motion of the workpiece, typical to surface grinding. The most general steady state solution is applied to the governing equations to give insight into the dynamic behavior of surface grinding. The theory predicts that steady state surface grinding vibrations can exist. They occur at a frequency which is always higher than the system’s uncoupled resonant frequency and slightly dependent on the workpiece’s direction of motion. Further, the model predicts the existence of wheel lobes. The lobes precess around the wheel according to their size, the wheel wear coefficient, and the chatter amplitude. The model suggests that the lobes can produce a rough ground surface even in the absence of dynamic grinding forces. As Part 2 of the presentation, some test results are offered in support of the mathematical theory of Part 1.

scholarly journals Deposition of dinitrogen pentoxide, N<sub>2</sub>O<sub>5</sub>, to the snowpack at high latitudes

2011 ◽  
Vol 11 (10) ◽  
pp. 4929-4938 ◽  
Author(s):  
D. M. Huff ◽  
P. L. Joyce ◽  
G. J. Fochesatto ◽  
W. R. Simpson
Keyword(s):  
Steady State ◽  
Gradient Method ◽  
Loss Rate ◽  
Deposition Velocity ◽  
Ground Surface ◽  
High Latitudes ◽  
Field Campaign ◽  
Dinitrogen Pentoxide ◽  
Knowledge Based ◽  
Winter Conditions

Abstract. Dinitrogen pentoxide, N2O5, is an important nighttime intermediate in the oxidation of NOx that is hydrolysed on surfaces. We conducted a field campaign in Fairbanks, Alaska during November 2009 to measure the gradient and derive a flux (and deposition velocity) of N2O5 depositing to snowpack using the aerodynamic gradient method. The deposition velocity of N2O5 under Arctic winter conditions was found to be 0.59 ± 0.47 cm s−1, which is the first measurement of this parameter to our knowledge. Based on the measured deposition velocity, we compared the chemical loss rate of N2O5 via snowpack deposition to the total steady state loss rate and found that deposition to snowpack is at least 1/8th of the total chemical removal of N2O5 that is located within the first few meters above the ground surface.

scholarly journals Temperature Distribution in Large, Pot-in-Pot Nursery Containers

1996 ◽  
Vol 14 (4) ◽  
pp. 170-176
Author(s):  
Roy E. Young ◽  
Gary R. Bachman
Keyword(s):  
Additional Data ◽  
Ground Surface ◽  
Temperature Profiles ◽  
Bare Ground ◽  
Southern States ◽  
Surface Control ◽  
Landscape Plants ◽  
Soil Temperatures ◽  
Data Points ◽  
Soil Mix

Abstract Container-grown landscape plants in the Mid-Atlantic and Southern states are exposed to wide, rapid fluctuations of temperatures, particularly during winter. Thermocouples were placed at three depths and four orientations in the soil mix of 2-year-old, Foster' hybrid holly (Ilex × attenuata ‘Fosteri’) to monitor temperature profiles of 57 liter (nominal 15 gal) containers. These containers were grown conventionally under three treatments: on a bare ground surface (control), inside plastic-film-covered hoop houses, and in the pot-in-pot (PIP) configuration below the ground surface. Temperatures were monitored during both the coldest and the warmest periods of the year in the Moncks Comer, SC, area. In the coldest period, soil temperatures averaged among depths and orientations were 3.6C (6.5F) warmer in the hoop houses than in the control, and 1.1C (2F) warmer in the PIP system than in the control. Although colder than the hoop houses, the average temperatures of the PIP container dropped below 0C (32F) only in the upper 7.6 cm (3 in). Below freezing averages were observed in the control containers, however, in all positions except the center. In the warmest period, the hoop houses were uncovered, becoming additional data points of the control treatments. The PIP system kept overall average soil temperatures 3.3C (6F) cooler than in control containers. Upon conclusion of the experiment, new (beyond transplanted root ball) root dry weights were significantly greater for PIP containers than for control containers.

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

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