Comparison of interpretation methods of thermocouple psychrometer readouts

2017 ◽  
Author(s):  
Łukasz Guz ◽  
Dariusz Majerek ◽  
Henryk Sobczuk ◽  
Ewa Guz ◽  
Bernard Połednik
Keyword(s):  
Thermocouple Psychrometer

Water potentials of seeds of Bromus inermis and Medicago sativa imbibed on media of various osmotic potentials

1976 ◽  
Vol 54 (17) ◽  
pp. 1997-1999 ◽  
Author(s):  
W. T. McDonough
Keyword(s):  
Polyethylene Glycol ◽  
Medicago Sativa ◽  
Bromus Inermis ◽  
Smooth Brome ◽  
Thermocouple Psychrometer ◽  
Water Potentials ◽  
The Media ◽  
Medicago Sativa L ◽  
Brome Grass ◽  
Osmotic Potentials

Seeds of smooth brome grass (Bromus inermis Leyss.) and alfalfa (Medicago sativa L. cultivar Ladak) were allowed to imbibe in water or solutions of polyethylene glycol (Carbowax 1540), mannitol, or sodium chloride. Seed water potentials were determined over a 72-h period after transfer of seeds to thermocouple psychrometer chambers. Seed water potentials were lower than osmotic potentials of the media, but these two potentials were not clearly related to each other. Possible reasons for the lack of gradation in response are discussed.

scholarly journals Measurement of xylem water pressure using High-Capacity Tensiometer and benchmarking against Pressure Chamber and Thermocouple Psychrometer

2020 ◽  
Vol 195 ◽  
pp. 03014
Author(s):  
Roberta Dainese ◽  
Giuseppe Tedeschi ◽  
Thierry Fourcaud ◽  
Alessandro Tarantino
Keyword(s):  
Water Flow ◽  
Water Pressure ◽  
High Capacity ◽  
Ground Surface ◽  
Pressure Chamber ◽  
Rainwater Infiltration ◽  
Thermocouple Psychrometer ◽  
Earth Structures ◽  
Pressure Water ◽  
The Stability

The response of the shallow portion of the ground (vadose zone) and of earth structures is affected by the interaction with the atmosphere. Rainwater infiltration and evapotranspiration affect the stability of man-made and natural slopes and cause shallow foundations and embankments to settle and heave. Very frequently, the ground surface is covered by vegetation and, as a result, transpiration plays a major role in ground-atmosphere interaction. The soil, the plant, and the atmosphere form a continuous hydraulic system, which is referred to as Soil-Plant-Atmosphere Continuum (SPAC). The SPAC actually represents the ‘boundary condition’ of the geotechnical water flow problem. Water flow in soil and plant takes place because of gradients in hydraulic head triggered by the negative water pressure (water tension) generated in the leaf stomata. To study the response of the SPAC, (negative) water pressure needs to be measured not only in the soil but also in the plant. The paper presents a novel technique to measure the xylem water pressure based on the use of the High-Capacity Tensiometer (HCT), which is benchmarked against conventional techniques for xylem water pressure measurements, i.e. the Pressure Chamber (PC) and the Thermocouple Psychrometer (TP).

Temperature Effects on Soil Suction for Compacted Clay Soils

2013 ◽  
Vol 723 ◽  
pp. 527-534
Author(s):  
Shu Rong Yang ◽  
Wei Hsing Huang ◽  
Shao Hung Chung
Keyword(s):  
Water Content ◽  
Clayey Soil ◽  
Expansive Soils ◽  
Soil Suction ◽  
Compacted Clay ◽  
Subgrade Soils ◽  
Thermocouple Psychrometer ◽  
Effects Of Temperature ◽  
Paper Method ◽  
Water Contents

An investigation was conducted to determine the effects of temperature, compaction water content, and compaction efforts on soil suction of two expansive subgrade soils. For this purpose, two expansive soils were statically compacted at target water contents ranging from 5% to 20%. This made it possible to explore a broad spectrum of compaction conditions. Filter paper method and thermocouple psychrometer were used to measure soil suction at temperatures ranging from 10°C to 60°C. Experimental results show that compaction water content, compaction effort, and temperature have influences on soil suction. As water content increases, the influences of compaction effort and temperature on suction become less significant. Finally multiple regression formulations for predicting the soil suction of as-compacted clayey soil were established.

Corrigenda - Measurement of the total water potential of aqueous solutions of polyethylene glycol - A comparison between osmometer, thermocouple psychrometer and equilibrated soil cores

Soil Research ◽  
1993 ◽  
Vol 31 (1) ◽  
pp. 1
Author(s):  
IM Wood ◽  
IK Dart ◽  
HB So
Keyword(s):  
Polyethylene Glycol ◽  
Water Potential ◽  
Close Correlation ◽  
Ease Of Use ◽  
Effect Of Temperature ◽  
Soil Cores ◽  
Total Water ◽  
Matric Potential ◽  
Thermocouple Psychrometer ◽  
Water Potentials

This study examined two polyethylene glycol (PEG) polymers (PEG 6000 and PEG 10000) and compared measurements of water potential obtained with a thermocouple osmometer and thermocouple psychrometers at three temperatures (15, 25 and 35�C) and five osmdalities (50, 100, 200, 300 and 400 g/1000 g water). These were then compared with estimates of matric potential of three soils brought to equilibrium with PEG solutions of the same osmolalities. At the same osmolality and temperature the two PEG polymers gave essentially the same water potential. There was a significant effect of temperature on water potential which corresponded closely with changes in specific gravity of the PEG solution. There was a close correlation between the measurements of water potential of the PEG solutions obtained with the osmometer and the psychrometers (R = 0.99). However, the psychrometer gave increasingly lower values than the osmometer as water potential decreased. The differences in the measurements between the two methods are thought to be the result of design and calibration differences. The ease of use of the osmometer is such that it is recommended for routine use. The water potentials of the soil cores brought to equilibrium with the PEG 10 000 solution were linearly related to the water potentials of the PEG solutions estimated from both the osmometer and psychrometers (R2 = 0.84). However, there were clear deviations from a 1:l relationship. It was concluded that the results from the soil cores could not be used to determine which of the two instruments gave the more accurate measurement of water potential of PEG solutions.

An Investiagtion of Thermocouple Psychrometer, I

1953 ◽  
Vol 8 (6) ◽  
pp. 768-776 ◽  
Author(s):  
Suekichi Kawata ◽  
Yoshirō Ōmori
Keyword(s):  
Thermocouple Psychrometer
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