Process continued spontaneous

The common characteristic of any kind of dynamic equilibrium is the continuation of processes at the microscopic level but no net tendency for the system to change in either the forward or the reverse direction. That is, neither the forward nor the reverse process is spontaneous. Expressed thermodynamically,... 

L and the D/L ratio approaches zero. After the death of the living organism, proteins start to spontaneously break down. An inter-conversion of the amino acids occurs from one chiral form (L) to a mixture of D- and L- forms following protein degradation this process is called amino acid racemisation. The extent of racemisation is measured by the ratio of D/L isomers and increases as a function of time and temperature. The longer the racemisation process continues the closer to 1 the ratio between the D- and L-forms becomes. If the D/L ratio is <1 it may be possible to use it to estimate age. The D/L ratio of aspartic acid and isoleucine are the most widely used for this dating technique [104]. Dates have been obtained as old as 200 000 years. However, it has been used mainly to date samples in the 5000 100 000 year range. Recent studies [ 105] mention an estimation of the method accuracy to be around 20%. 

These are produced by autoionization transitions from highly excited atoms with an inner vacancy. In many cases it is the main process of spontaneous de-excitation of atoms with a vacancy. Let us recall that the wave function of the autoionizing state (33.1) is the superposition of wave functions of discrete and continuous spectra. Mixing of discrete state with continuum is conditioned by the matrix element of the Hamiltonian (actually, of electrostatic interaction between electrons) with respect to these functions. One electron fills in the vacancy, whereas the energy (in the form of a virtual photon) of its transition is transferred by the above mentioned interaction to the other electron, which leaves the atom as a free Auger electron. Its energy a equals the difference in the energies of the ion in initial and final states ... 

Rusting, like many other processes, is spontaneous. A spontaneous process is a physical or chemical change that occurs with no outside intervention. However, for many spontaneous processes, some energy must be supphed to get the process started. For example, you may have used a sparker or a match to hght a Bunsen burner in your school lab. Or perhaps you are famihar with the continuously burning pilot lights that are used in gas stoves and furnaces to start these appliances immediately. Once the gas has been ignited, the combustion process can proceed spontaneously. 

For a transformation at constant pressure p and temperature T, equilibrium will correspond to a minimum of the free enthalpy. Otherwise, the process would spontaneously continue. For equilibrium, the following expression can be written for the closed system ... 

The process of spontaneous parametric downconversion has been studied extensively [79,80] for cw (continuous-wave) pump lasers over the last decades. A great deal of attention has been paid to the process of spontaneous parametric... 

Plutonium is a radioactive element. Radioactive elements are those that undergo spontaneous transformation (decay) in which energy is released (emitted) either in the form of particles, such as alpha or beta particles, or waves, such as gamma or X-ray. This transformation or decay results in the formation of new elements, some of which may themselves be radioactive, in which case they will also decay. The process continues until a stable (nonradioactive) state is reached (see Appendix B for more information). 

Our experiments reveal the concentration gradients (between the portion of the aqueous phase that is accessible to smaller ions, only, and the rest of the solution) as the driving force for squeezing these smaller ions into the fine pores and additional exclusion of the largest ions into the rest of the hquid phase. This process of spontaneous redistribution of electrolytes between the above two compartments of the aqueous phase continues until the total concentration of electrolytes in all parts of the liquid phase levels out. If this mechanism of the spontaneous separation of electrolytes corresponds to reality, it must operate in all nanoporous separation media and with aU types of electrolytes. 

Components dissolved in water are in a state of continuous motion. Ihis is caused by different forces that affect the magnitude and direction of rates. Any spontaneous mass transfer in ultimately results in an increase of the system s entropy. That is why at the foundation of the description of any processes of spontaneous mass transfer are the thermodynamical laws of irreversible processes. According to these laws the rate at which forms entropy, i.e., entropy production a, is associated with flows of matter dispersion through the following equation... 

As mentioned, entropy always moves spontaneously from warmer locations to colder ones (Fig. 3.14). When fast moving atoms collide with ones moving more slowly, they are themselves slowed while their collision partners speed up. As a result, the agitation and, therewith, the total disorder at the warmer locations gradually decrease while they continuously increase at the colder locations. In a homogeneous body, the process continues until the level of agitation is the same everywhere and the body is equally warm everywhere. This state is called thermal equilibrium. 

Thus, ATy jjjax and Apv,max representative for the same phenomena and can be indifferently used to calculate the maximum theoretical specific power l th,max-Nevertheless, the continuous exploitation of such a pressure difference is not trivial since the process evolves spontaneously to an equilibrium condition. Vapor formation causes the liquid phase to cool down, with a reduction in vapor pressure at the freshwater chamber. In the other chamber, vapor condenses with an increase of temperature and vapor pressure. If no heat is provided to the freshwater chamber and extracted from the saltwater chamber, the small pressure difference that drives the process rapidly vanishes, causing an interruption in the vapor flow. 

Some processes occur without any outside intervention, and we say that such a process is spontaneous. From a thermodynamic perspective, then, a spontaneous process is one that takes place without continuous intervention. The distinction between spontaneous and nonspontaneous reactions may seem obvious, but we ll see that it is not always so. 

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