Theory, versus practice

Libby P, Ridker PM. Novel inflammatory markers of coronary risk Theory versus practice. Circulation. 1999, 100 1148-1150. 

Griffin JW, May JR, DiPiro JT. Drug interactions theory versus practice. AmJMed( 9S4) 77 (Suppl 5B), 85-9. 

Vitiello, B., and Burke, L. (1998) Generic methylphenidate versus brand Ritalin which should be used. In Greenhill, L. and Osman, B., eds. Ritalin Theory and Practice, 2nd ed. Larchmont, NY Mary Ann Liebert, Inc., pp. 221-226. 

In a number of instances a decision had to be taken as to what to call "fundamentals and what "advanced". In the case of electric double layers, this decision related to the classical Gouy-Stern theory versus modem statistical theories. For pragmatic reasons we decided to emphasize the former the equations are simple and analytical, and can account for the great majority of situations met in practice. However, a section is Included to give an impression of more a priori statistical approaches. In the domain of electrokinetics the decision was between simple theories on the level of Helmholtz-Smoluchowski (HS), that may apply to perhaps 30-50% of all systems studied in practice, or on... 

Eads, George, U.S. Government Support for Civilian Technology Economic Theory Versus Political Practice," Research Policy (197 ), pp. 2-l6. 

T , See melt temperature, theorem See mathematical theorem, theoretical versus actual properties See plastics, theoretical versus actual values of. theory A unifying principle that explains a body of facts and tbe laws that are based on those facts. See atomic theory design design-failure theory design theory and strength of material empirical engineering approach versus practical approach mathematical theorem mixing theory. 

Castagna, J.P., 1993. Amplimde-versus-offset analysis tutorial and review. In Castagna, J.P., Backus, M.M. (Eds.), Offset-Dependent Reflectivity— Theory and Practice of AVO Analysis. Society of Exploration Geophysicists, Tulsa OK/USA. 

In fig. 26 the Arrhenius plot ln[k(r)/coo] versus TojT = Pl2n is shown for V /(Oo = 3, co = 0.1, C = 0.0357. The disconnected points are the data from Hontscha et al. [1990]. The solid line was obtained with the two-dimensional instanton method. One sees that the agreement between the instanton result and the exact quantal calculations is perfect. The low-temperature limit found with the use of the periodic-orbit theory expression for kio (dashed line) also excellently agrees with the exact result. Figure 27 presents the dependence ln(/Cc/( o) on the coupling strength defined as C fQ. The dashed line corresponds to the exact result from Hontscha et al. [1990], and the disconnected points are obtained with the instanton method. For most practical purposes the instanton results may be considered exact. 

Autonomous (A) Versus Nonautonomous (NA) Problems. Practically all nonlinear problems of the theory of oscillations reduce to the differential equation of the form... 

The case of m = Q corresponds to classical Arrhenius theory m = 1/2 is derived from the collision theory of bimolecular gas-phase reactions and m = corresponds to activated complex or transition state theory. None of these theories is sufficiently well developed to predict reaction rates from first principles, and it is practically impossible to choose between them based on experimental measurements. The relatively small variation in rate constant due to the pre-exponential temperature dependence T is overwhelmed by the exponential dependence exp(—Tarf/T). For many reactions, a plot of In(fe) versus will be approximately linear, and the slope of this line can be used to calculate E. Plots of rt(k/T" ) versus 7 for the same reactions will also be approximately linear as well, which shows the futility of determining m by this approach. 

Sometimes forms deviating from simple linear relations were used in this early work, particularly the relation of log A to E (31,36), which was derived theoretically (29) but later rejected (37, 38). Otherwise, the quantity log (kM ) was plotted instead of log k, M" being the sum of reciprocal masses of reacting particles according to collision theory (33), and this correction was also later abandoned (34). The two modifications mentioned, in practice, have little influence on the shape of the graph, and the simple plot of E versus log A (or AH versus AS) is now preferred. 

Most chemists are well acquainted with LCAO-MO theory. The numbers of atomic orbitals, even in large molecules, however, are miniscule compared to a nonmolecular solid, where the entire crystal can be considered one giant molecule. In a crystal there are in the order of 10 atomic orbitals, which is, for all practical purposes, an infinite number. The principle difference between applying the LCAO approach to solids, versus molecules, is the number of orbitals involved. Fortunately, periodic boundary conditions allow us to smdy solids by evaluating the bonding between atoms associated with a single lattice point. Thus, the lattice point is to the solid-state scientist, what the molecule is to the chemist. 

Love versus Cigarettes Tlii.-se Jays I run into lots of icople who have stopped smoking, and they always say, "You could do it, too." 1 suppose they re right in theory. I mean, in theory I could run the triathalon if 1 put my mind to it, but in practice I know it isn t so. 

Obstacles to practical application of the Langmuir and Freundlich isotherm theories include the following (1) These isotherms do not effectively address adsorption versus degradation and competitive adsorption (2) the conclusions are not all inclusive i.e., adsorption constants and coefficients do not hold true in all cases within similar oil types let alone across different oil types (3) the process has so many variables that the additive variance is commonly too great to prove any subtle difference between clays other than a vastly different level of activity (this problem is especially true when using log vs. log plots with incremental changes on the order of 0.1%) and (4) the adsorption constants and coefficients have limited use for the refiner. 

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