Gurney energy

Comparison of Gurney Energies with Heats of Detonation. V 83... 

Equating the total kinetic energy to the Gurney energy of the expl gives... 

The first and common description of the explosive performance is the detonation velocity D (measured at a desirably high charge density). This is not sufficient as resulted by our own research on light-element explosives (ANQ, TAGN), which exhibited besides attractive D values only low ballistic performance not predicted by model calculations. So as a second base is applied the Gurney energy JIEq. For a more profound analysis we recommend the brisance of an explosive which can be quantified by the depth (or the volume) of the denting from a detonation on a steel plate, the Plate Dent Test. 

The Gurney energy is most frequently obtained experimentally from cylinder test data. Additionally, on the basis of more detailed theoretic consideration of the detonation products and the wall material expansion process, the cylinder test makes it possible to calculate the detonation pressure and the heat of the detonation of an explosive. 

The increase of the cylinder external r us is viewed at a constant section of the cylinder, oppK>site to the cylinder axis. The optical methods are most frequently applied. The cylinder external radius vs. time curve, the so-called expansion curve, is thus obtained. The treatment of the curve yields the wall velocity and the Gurney energy. 

Although the cylinder test appears to be a simple method, the treatment of the data provides a lot of important information regarding the tested explosive. It gives us the Gurney energy (from cylinder wall velocity) and the equation of the detonation products isentropic expansion. 

Calculation of the Cylinder Wall Velocity. By simple graphical or analytical treatment of the cylinder expansion curve, one can obtain cylinder wall velocity as a tangent to the curve, if determined graphically, or as a derivation of an analytical expression, if determined analytically. Consequently, the Gurney energy may be calculated according to Eq. (5.38). 

Finally, as the aim of the test, the Gurney energy may be calculated from the genuine wall velocity and acceleration. 

In any case it resulted that there are two relatively stable configurations in the first the two non polar solutes are in contact inside the same water cage, in the other one molecule of water is interposed between the two solute molecules. This picture of hydrophobic interactions is coherent with that formulated to interpre-te the results of a statistical mechanical study of the hydrophobic interaction(140) in which is used a potential of average force obtained as a sum of the vacuum potential and a Gurney energy functi-on(141). 

A case can be made for the usefulness of surface tension as a concept even in the case of a normal liquid-vapor interface. A discussion of this appears in papers by Brown [33] and Gurney [34]. The informal practice of using surface tension and surface free energy interchangeably will be followed in this text. 

The entropy of a solution is itself a composite quantity comprising (i) a part depending only on tire amount of solvent and solute species, and independent from what tliey are, and (ii) a part characteristic of tire actual species (A, B,. ..) involved (equal to zero for ideal solutions). These two parts have been denoted respectively cratic and unitary by Gurney [55]. At extreme dilution, (ii) becomes more or less negligible, and only tire cratic tenn remains, whose contribution to tire free energy of mixing is... 

The compliance methods are all based on the equation for the critical strain energy release rate, Gic, based on Gurney and Hunt (1967)... 

All this material is described in introductory textbooks of physics and chemistry. However, it is interesting to recall the headlines here because the veiy first application to a chemical theme of the ideas of waves in quantum mechanics was to explain how electrons were emitted from, or accepted by, electrodes. This was the achievement of Ronald Gurney,1 the first physical electrochemist, and much of this chapter is based on developments that sprang from his seminal paper of 1931. In this paper, he related electric currents across the electrode solution interface to the tunneling of electrons through energy barriers formed between the electrode and the ions or molecules in the first layer next to the electrode (possessing electronic states ). 

The essentials of quantum kinetics were in place by 1954, Weiss having added to the Gurney theory a comprehensive theory of redox reactions. By this date, tunneling, adiabatic and non-adiabatic electron transfer, the simplicity introduced by considering redox reactions between isotopes, the separate contribution from outer sphere and inner sphere, and in particular the equation for the reorganization energy involving and stat had all been published. 

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