An improved radiation protected differential thermocouple psychrometer for crop environment

Abstract The heat of vulcanization of rubber compounds containing various quantities of sulfur and several organic vulcanization accelerators were traced by means of a differential thermocouple during the vulcanization. The profiles of the heating curves were similar to those obtained in the case of unaccelerated compounds, but the temperature maxima appeared sooner with accelerated than with unaccelerated compounds. The vulcanizates corresponding to the temperature-maxima were analyzed chemically by ordinary methods and the ratios of the free to total sulfur were calculated. They vary a little from 50 per cent, and show that the extent of sulfur combination is not much different from that with unaccelerated compounds. The accelerators tested were hexamethylenetetramine, aldehyde-ammonia diphenylguanidine, di-o-tolylguanidine, p-nitrosodimethylaniline, thiocarbanilide, “Vulkacit P”, “Vulkacit PX”, “Vulkacit M”, and tetramethylthiuramdisulfide The results of the experiments show that these accelerators promote the disaggregation of the micellar structure of rubber (as shown in reports II and III 0. this work) before chemical combination of rubber and sulfur occurs. By thus making the single micelle of rubber smaller, they increase the number of chemical units of rubber coming into reaction with sulfur; i. e., the probability of combination of rubber and sulfur becomes greater. The times for the temperature maxima to appear in the experiments above, which are shortened by accelerators, show that this theory holds good, when it is considered that the temperature maxima correspond to the disaggregation maxima of the rubber hydrocarbon under consideration.

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Differential Thermocouple up to 2450°C and Thermographic Investigation of Refractory Silicides

Advances in Instrumentation ◽

10.1007/978-3-0348-7413-7_49 ◽

1972 ◽

pp. 549-559 ◽

Cited By ~ 1

Author(s):

Ju. A. Kocherzhinsky

Keyword(s):

Differential Thermocouple ◽

Thermographic Investigation

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

Canadian Journal of Botany ◽

10.1139/b76-213 ◽

1976 ◽

Vol 54 (17) ◽

pp. 1997-1999 ◽

Cited By ~ 6

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.

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

E3S Web of Conferences ◽

10.1051/e3sconf/202019503014 ◽

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).

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