scholarly journals An Intrinsic Geometric Formulation of Hyper-Elasticity, Pressure Potential and Non-Holonomic Constraints

2021 ◽  
Author(s):  
B. Kolev ◽  
R. Desmorat
Keyword(s):  
Pressure Potential ◽  
Holonomic Constraints ◽  
Geometric Formulation

Deterministic Mechanism of Irreversibility

2018 ◽  
Vol 14 (3) ◽  
pp. 5708-5733 ◽  
Author(s):  
Vyacheslav Michailovich Somsikov
Keyword(s):  
Internal Energy ◽  
Hamiltonian Systems ◽  
Classical Mechanics ◽  
Motion Equation ◽  
Holonomic Constraints ◽  
Dissipative Processes ◽  
Motion Energy ◽  
Analytical Review ◽  
History Of ◽  
Material Points

The analytical review of the papers devoted to the deterministic mechanism of irreversibility (DMI) is presented. The history of solving of the irreversibility problem is briefly described. It is shown, how the DMI was found basing on the motion equation for a structured body. The structured body was given by a set of potentially interacting material points. The taking into account of the body’s structure led to the possibility of describing dissipative processes. This possibility caused by the transformation of the body’s motion energy into internal energy. It is shown, that the condition of holonomic constraints, which used for obtaining of the canonical formalisms of classical mechanics, is excluding the DMI in Hamiltonian systems. The concepts of D-entropy and evolutionary non-linearity are discussed. The connection between thermodynamics and the laws of classical mechanics is shown. Extended forms of the Lagrange, Hamilton, Liouville, and Schrödinger equations, which describe dissipative processes, are presented.

Accuracy and Usefulness of Psychrometer and Pressure Chamber for Evaluating Water Potentials of Pinus radiata Needles

1982 ◽  
Vol 9 (5) ◽  
pp. 499 ◽  
Author(s):  
BD Millar
Keyword(s):  
Water Potential ◽  
Pinus Radiata ◽  
Xylem Sap ◽  
Pressure Chamber ◽  
Pressure Potential ◽  
Pine Trees ◽  
Average Water ◽  
Potential Gradients ◽  
Fundamental Uncertainty ◽  
The One

Pressure chamber evaluations of xylem sap pressure potential (P) and thermocouple psychrometric evaluations of average water potential (Ψl) in needles from both transpiring and non-transpiring pine trees (Pinus radiata D. Don) were compared in order to determine the relative accuracy and usefulness of these methods for assessing Ψl. Markedly different but linear P v. Ψl relationships were obtained for pine needles of different age and also for the case where resin exudation masked the xylem and led to a 'resin error'. Evidence suggests that these differences are mainly due to injection and resin errors in pressure chamber determinations totalling as much as 1 MPa (a 10 bar). The psychrometric method appears to be the much more accurate. Radial water potential gradients across leaves did not result in differences between evaluations of P and Ψl, at least in P. radiata. The need for multiple 'calibrations' of the pressure chamber and the fundamental uncertainty about the constancy of such calibrations on the one hand and the slowness of the excised-needle psychrometer on the other can restrict the usefulness of these methods.

scholarly journals Geometric Formulation of BRS and BRS* Transformations in T4 Theory

1984 ◽  
Vol 71 (1) ◽  
pp. 174-182
Author(s):  
H. Kikukawa ◽  
J. Kikukawa
Keyword(s):  
Geometric Formulation

The effect of humidity, root excision, and potassium supply on hypocotyl elongation in dark-grown seedlings of Helianthus annuus

1984 ◽  
Vol 62 (3) ◽  
pp. 420-428 ◽  
Author(s):  
Gordon I. McIntyre ◽  
John S. Boyer
Keyword(s):  
Helianthus Annuus ◽  
Osmotic Potential ◽  
Stem Elongation ◽  
Growth Responses ◽  
Pressure Potential ◽  
Cell Turgor ◽  
Low Humidity ◽  
Potassium Supply ◽  
Root Excision ◽  
Growing Region

When seedlings of Helianthus annuus L. were grown in the dark with their roots in vermiculite saturated with distilled water the rate of elongation of the hypocotyl was significantly increased by increasing the relative humidity around the shoot from approximately 25 to 100%. This response was correlated with a reduction in transpiration rate of approximately 95% and with increases in the water potential and cell turgor in the growing region. Measurements with a transducer revealed very rapid growth responses to changes in humidity, usually preceded by a variable period of growth oscillations. Excision of the roots, either in water or in air, induced an immediate increase in rate of elongation at low humidity, but at high humidity this response was delayed and markedly reduced. The growth rate was significantly increased by supplying 10 mM KCl to the roots at both high and low humidity. The response to K was slower than the response to humidity and was correlated with a significant reduction in the osmotic potential of the growing region. A growth response was first detected approximately 45 min after the application of K to the roots and 10 min after application to the shoot. These results arc consistent with the hypothesis that, in the intact plant, stem elongation is largely controlled by the interacting effects on cell turgor of transpiration-induced negative pressure potential in the apoplast and the osmotic potential of the growing cells.

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