Times for calculations

Note Configuration Interaction significantly increases computing time. For calculations of ground-state energies, MINDO/3, MNDO, AMI, and PM3 methods may already include in their parameters some effects of Configuration Interaction. 

The computation time for calculations of energy losses to the ground can be quite significant because of the three-dimensional heat conduction problem. Simplified methods are given in ISO/FDIS 13370 1998. ... 

TABLE 1—Time for calculating multisummation on different grids (units s). ... 

Also, like all cubic equations of state,Eqn. (1) requires relatively little computing time for calculating thermophysical properties. 

Period of time for calculation (e.g., a calendar year) duration... 

The (N — l)-electron potential method has been used many times for calculating the excited states of molecules and has exhibited a good agreement with experiment. For example, Goddard and Hunt (1974) have calculated 32 excited states of H20 molecule and have compared the calculated excitation energies with eight experimental values obtained from the electron and photon spectroscopy measurements. They have noted that the average discrepancy between the calculated and experimental values is about 1 eV. The introduction of a scale factor reduces this discrepancy to about 0.1 eV. 

Table 8. Computation times for calculation of the descriptor sets for the 16380 compounds of the virtual library.

All certificates must contain information that identifies the physical, chemical, and radiological properties of the SRM. Physical properties include density and mass. Chemical properties identify composition such as chemical form, acidity, and salt content. Radiological properties are the name of the radionuclide, the decay scheme, half-life, daughter radionuclides, reference time for calculating decay, and radionuclide impurity amounts. The most important information is the radionuclide activity or concentration and the uncertainty of this value. Details must be provided about the technique used to determine activity and the basis for the uncertainty value. Technical information such as the production method also may be given on the certificate. 

As one may deduce from Table 1, the computational cost of full-direa MP2 calculations grows with the fifth power of the number of basis functions. The timings given in Table 1 are for runs constrained to 14 MW of the core memory. Decreasing the size of the core memory to 7 MW would result in a doubling of the CPU time for calculations on benzene, naphthalene, and anthracene. Calculations on tetracene and pentacene would not run with this amount of the core memory. 

Method of constant equilibrium (physicochemical) is based on the search of such water composition, at which activities or concentrations of components would be tied between themselves by equilibrium constants, according to the mass-action law. This method is commonly used in physical chemistry, especially in the chemistry of complex compounds, as it solves most of their problems. Its application in hydro-geochemistry is due to the fact that computer programs developed on its base are simpler and, as a rule, take less time for calculations. 

Repeated exercise leads to functional adaptations in humans. The aerobic capacity, quantified using the maximum oxygen uptake, may increase to values over 61/min (Figure 7.2). This means that more than 2000 W of heat can be produced for a short period of time (for calculation of the heat balance, see Daanen et al., 2006 Astrand et al., 2003). This amount of produced heat has to be lost quickly if not, the core temperature will increase with 5 °C in 10 min. The mechanism to enhance sweating is strongly dependent on body core temperature when a certain threshold is surpassed, the sweat rate shows a sharp increase. 

Due to the fact that the computer time for calculating the atomic interactions generally increases with approximately the square of the number of investigated atoms, one still needs simple systems consisting of a relatively small number of molecules. Whereas chemists usually work with molar quantities, molecular dynamics... 

In order to reduce the computation time for calculation of the non-bonded interactions, it is inevitable to truncate the range of intermolecular van der Waals and electrostatic interactions. In practice, periodic simulation... 

The capabilities of the suggested method for studying the nonlinear dynamie systems are demonstrated by the example of the above-mentioned Oregonator skeletal model, describing the B-Zh reaction. To simulate an open reaction system the concentrations for A and B were kept constant with time. For calculations the extremal behavior of concentration for the activator X was adopted as a critical condition ... 

The Bateman equation was used at two different times for calculation of the initial °Sr/ V activities. That is to say, total beta activity, i.e. °Sr activity and its daughter was measured at two different times, one along the first day after the separation process and another when the secular equilibrium was reached. Main advantages of this method are the little amount of resin used and its long durability (up to 30 injections) achieving an MDA of 0.008 Bq °Sr. 

An important attribute of an equation of state for engineering applications is relative simplicity, resulting in minimal computation time for calculation of the necessary properties. Although the use of developed software has become common in engineering applications, situations that require user specific software are still frequent. If requirements of either precise estimate or demands with regard to the range of validity can be relaxed, then equations of state with fewer terms for specified levels of precision may be developed to reduee eom-putation times. 

The analysis of timings for calculations we have made using simple potentials indicates that only a very small firaction of the overall run time is spent cdculating the intra-arrangement potential coupling matrix elements. However,... 

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