Energy, specific

The term specific energy is used indiscriminately for gravimetric energy density and volumetric energy density. Similarly, as with the specific 

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Due to the very high intensity of the laser beams and their coherent nature they may be used in a variety of ways where controlled energy is required. Lasers are used commercially for excitation with a specific energy, e.g. in Raman spectroscopy or isotope separation. 

If one imagine.s that the fuel is used in the liquid state in the form of droplets —as in the case of fuel injection— the specific energy of the motor fuel (SE) is expressed in kilojoules per kilogram of air utilized, under predetermined conditions of equivalence ratio (stoichiometry for example). The SE is none other than the NHY /r quotient where r represents the previously defined stoichiometric ratio. 

Table 5.4 gives the specific energies of selected organic liquid compounds. Compared with the isooctane chosen as the base reference, the variations from one compound to another are relatively small, on the order of 1 to 5%, with the exception of some particular chemical structures such as those of the short chain nitroparaffins (nitromethane, nitroethane, nitropropane) that are found to be energetic . That is why nitromethane, for example, is recommended for very small motors such as model airplanes it was also used in the past for competitive auto racing, for example in the Formula 1 at Le Mans before being forbidden for safety reasons. 

Generally speaking, intermolecular forces act over a short range. Were this not the case, the specific energy of a portion of matter would depend on its size quantities such as molar enthalpies of formation would be extensive variables On the other hand, the cumulative effects of these forces between macroscopic bodies extend over a rather long range and the discussion of such situations constitutes the chief subject of this chapter. 

It is also instructive to start from the expression for entropy S = log(g(A( m)) for a specific energy partition between the two-state system and the reservoir. Using the result for g N, m) in section A2.2.2. and noting that E = one gets (using the Stirling approximation A (2kN)2N e ). 

Since E = - 2 iU)tn., a given spin excess value 2m. implies a given energy partition. The free energy for such a specific energy partition is... 

Typically, the ratio of this to the incident flux detennines the transition probability. This infonnation will be averaged over the energy range of the initial wavepacket, unless one wants to project out specific energies from the solution. This projection procedure is accomplished using the following expression for the energy resolved (tune-independent) wavefunction in tenns in tenns of its time-dependent counterpart ... 

For qualitative purposes the circle itself isn t even necessary We could locate the Huckel MOs by simply working with the polygons themselves The circle is needed only when Frost s method is used quantitatively In those cases the radius of the circle has a prescribed value allowing each MO to be assigned a specific energy... 

Based on the bench-scale data, two coal-to-acetylene processes were taken to the pilot-plant level. These were the AVCO and Hbls arc-coal processes. The Avco process development centered on identifying fundamental process relationships (29). Preliminary data analysis was simplified by first combining two of three independent variables, power and gas flow, into a single enthalpy term. The variation of the important criteria, specific energy requirements (SER), concentration, and yield with enthalpy are indicated in Figure 12. As the plots show, minimum SER is achieved at an enthalpy of about 5300 kW/(m /s) (2.5 kW/cfm), whereas maximum acetylene concentrations and yield are obtained at about 7400 kW/(m /s) (3.5 kW/cfm). An operating enthalpy between these two values should, therefore, be optimum. Based on the results of this work and the need to demonstrate the process at... 

Fig. 12. Critical process parameters as a function of gas enthalpy where A is yield, B is concentration, and C is the specific energy requirement (SER).

Usually the specific energy consumption, is reported in kWh /kg of product ... 

Experimental studies show that the ozone concentration iacreases with specific energy (eV/O2) before reaching a steady state. The steady-state ozone concentration varies iaversely with temperature but directiy with pressure, reaching a maximum at about 101.3 kPa (1 atm). Above atmospheric pressure the steady-state ozone concentration decreases with pressure, apparentiy due to the pressure dependence of the rate constant ratio for the... 

The results of the theory of quantum mechanics require that nuclear states have discrete energies. This is in contrast to classical mechanical systems, which can have any of a continuous range of energies. This difference is a critical fact in the appHcations of radioactivity measurements, where the specific energies of radiations are generally used to identify the origin of the radiation. Quantum mechanics also shows that other quantities have only specific discrete values, and the whole understanding of atomic and nuclear systems depends on these discrete quantities. 

The gray is also used for the ionising radiation quantities, specific energy imparted, kerma, and absorbed dose index, which have the SI unit joule per kilogram. 

Table 1. Specific Energies and Energy Densities of Carbon-Zinc Cells ...

Li—Al/FeS cells have demonstrated good performance under EV driving profiles and have deUvered a specific energy of 115 Wh/kg for advanced cell designs. Cycle life expectancy for these cells is projected to be about 400 deep discharge cycles (63). This system shows considerable promise for use as a practical EV battery. 

For a given fixed flow rate Q = Vbh, and channel width profile b(x), Eq. (6-56) may be integrated to determine the liquid depth profile h(x). The dimensionless Fronde number is Fr = VVg/j. When Fr = 1, the flow is critical, when Fr < 1, the flow is subcritical, and when Fr > 1, the flow is supercritical. Surface disturbances move at a wave velocity c = V they cannot propagate upstream in supercritical flows. The specific energy Ejp is nearly constant. 

The fineness to which a material is ground has a marked effect on its production rate. Figure 20-8 is an example showing how the capacity decreases and the specific energy and cost increase as the product is ground finer. 

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