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Error growth

This is the characteristic equation for the eigenvalues posed by the Orr-Sommerfeld equation that also can be viewed as the dispersion relation of the problem. So the task at hand is to obtain a combination of a and u> for a given Re, such that the solution of OSE satisfies (2.4.8). The stiffness of OSE causes the numerical solution to lose the linear independence of different solution components corresponding to the different fundamental solutions. This is the source of parasitic error growth of any stiff differential equation. To remove this problem in a straight forward manner, one can use the Compound Matrix Method (CMM). [Pg.37]

Rounding errors are the first source of random noise in any finite precision computation they constitute an unavoidable forcing for the Navier-Stokes equations and may lead to LES variability. The study of error growth in finite precision computations is an important topic in applied mathematics [367 264] but has found few applications in multidimensional fluid mechanics because of the complexity of the codes used in CFD. [Pg.287]

In 49 the authors have presented a simple technique that allows to limit the error growth in the Ion-term (long-time) numerical integration of perturbed multi-dimensional oscillators, while using highly efficient and accurate special multistep codes. The author has studied theoretically their behaviour. The new technique has been illustrated with some numerical examples, including a case with non-resonant frequencies. [Pg.207]

If some of the errors given above can be dominated for the real zirconia-based sensors, then the other constituents can be ignored. If only the additive constituent part takes place, then the zirconia gas sensor function assumes y = k x Aq), where the current value of the absolute sensor error, equal to A = Aq, is independent of the value of the measuring parameter. The value of the relative error y= Yq = Aq /jc is inversely proportional to the value of the measuring parameter, the sensor error growths up to 100% at X = Ag, that is, it is impossible to make a measurement in this case. The value of the measuring parameter x, equal to the value of the relative error of zero, is acceptedly called the sensitivity threshold of the sensor. [Pg.230]

Error Growth in Numerical Integration of Differential Equations... [Pg.55]

Fig. 2.3 These graphs show the way in which the error grows in relation to time in simulations of the trimer using Euler s method. Le/i the growth of the logarithm of the trajectory error right the energy error growth as a function of time... Fig. 2.3 These graphs show the way in which the error grows in relation to time in simulations of the trimer using Euler s method. Le/i the growth of the logarithm of the trajectory error right the energy error growth as a function of time...
In the left-hand panel of Fig. 2.4 we report the Verlet error growth as a function of time for the Lennard-Jones trimer. Verlet is substantially more accurate in this simulation, although the error still appears to grow exponentially. [Pg.69]

A method was given in [184] based on a modified collision procedure which greatly reduces the error growth. [Pg.135]

Curve D in Fig. 3 shows how the rms error would grow with time if we assume that the initial rms error of 10 m grows with the doubling time of 2 days, and the rms will approach the asymptotic value of 145 m as seen from persistence forecasts. There are uncertainties as to the values of both the error growth rate and the level of error saturation, as well as the value of initial error. In fact, the use of 2-day error growth rate may be too optimistic since the quoted value tends to decrease in advanced models, which use high spatial grid resolutions and incorporate the physical processes of smaller scale motions that have much... [Pg.385]

Extended defects range from well characterized dislocations to grain boundaries, interfaces, stacking faults, etch pits, D-defects, misfit dislocations (common in epitaxial growth), blisters induced by H or He implantation etc. Microscopic studies of such defects are very difficult, and crystal growers use years of experience and trial-and-error teclmiques to avoid or control them. Some extended defects can change in unpredictable ways upon heat treatments. Others become gettering centres for transition metals, a phenomenon which can be desirable or not, but is always difficult to control. Extended defects are sometimes cleverly used. For example, the smart-cut process relies on the controlled implantation of H followed by heat treatments to create blisters. This allows a thin layer of clean material to be lifted from a bulk wafer [261. [Pg.2885]

Forward Analysis In this type of analysis, we are interested in the propagation of initial perturbations Sxq along the flow of (1), i.e., in the growth of the perturbations 5x t xo) = (xo -h Sxq) — xq. The condition number K,(t) may be defined as the worst case error propagation factor (cf. textbook [4]), so that, in first order perturbation analysis and with a suitable norm j ... [Pg.99]

Lonally, the templates were chosen by trial and error or exhaustive enumeration. A itafional method named ZEBEDDE (ZEolites By Evolutionary De novo DEsign) en developed to try to introduce some rationale into the selection of templates et al. 1996 Willock et al. 1997]. The templates are grown within the zeolite by an iterative inside-out approach, starting from a seed molecule. At each jn an action is randomly selected from a list that includes the addition of new (from a library of fragments), random translation or rotation, random bond rota-ing formation or energy minimisation of the template. A cost function based on erlap of van der Waals spheres is used to control the growth of the template ale ... [Pg.710]

SEM = standard error of the means. IGF-I = insulin-like growth factor I. [Pg.412]

Deficiency or Toxicity in Humans. Molybdenum deficiency in humans results in deranged metaboHsm of sulfur and purines and symptoms of mental disturbances (130). Toxic levels produce elevated uric acid in blood, gout, anemia, and growth depression. Faulty utiH2ation results in sulfite oxidase deficiency, a lethal inborn error. [Pg.387]

Improvement in business performance is essential for growth and profit, but the ISO/TS 16949 requirements are not concerned with your growth and profits they are concerned with product quality, and one definition of product quality that signals improvement potential is freedom from defects . Achieving quality become a quest to eliminate defects and in so doing reduces variation in the operational processes, but even when there are no defectives, there will still be variation. One might well question the need to reduce variation when there are no defectives but by reducing variation you will have fewer breakdowns, fewer errors, less space allocated to inventory, less waste, etc. in fact fewer problems and increased profit as a result. [Pg.110]

It is even more diffieult to estimate not only one but four parameters (nueleation rate, growth rate, agglomeration kernel and disruption kernel) simultaneously from a partiele size distribution. The errors are likely to be unaeeeptably high and it might be impossible to distinguish between the meehanisms involved. Therefore, an alternative sequential teehnique has been developed to obtain the kinetie parameters nueleation rate, growth rate, and agglomeration and disruption kernels from experimental preeipitation data. [Pg.177]

The proof of protection is more difficult to establish in this case for two reasons. First, the object is to restore passivity to the rebar and not to render it virtually immune to corrosion. Second, it is difficult to measure the true electrode potential of rebars under these conditions. This is because the cathodic-protection current flowing through the concrete produces a voltage error in the measurements made (see below). For this reason it has been found convenient to use a potential decay technique to assess protection rather than a direct potential measurement. Thus a 100 mV decay of polarisation in 4 h once current has been interrupted has been adopted as the criterion for adequate protection. It will be seen that this proposal does not differ substantially from the decay criterion included in Table 10.3 and recommended by NACE for assessing the full protection of steel in other environments. Of course, in this case the cathodic polarisation is intended to inhibit pit growth and restore passivity, not to establish effective immunity. [Pg.123]

Mayo, D. (1996) Error and the Growth of Experimental Knowledge (Chicago University of Chicago Press). [Pg.89]

Growth inhibition by TGF- 3, associated with inhibition of c-myc, cdks, reduction in cyclin D1 levels, and inhibition of cdk-4-associated Rb kinase activity, as well as induction of cdk inhibitors pi5 and p27, has been noted in intestinal epithelial cells. Loss of responsiveness to growth inhibition from TGF- 3 occurs in many cell types including breast, colorectal carcinoma, and pancreatic carcinoma cells. Mutational inactivation of T 3RH represents one mechanism of this process, which in many cases, leads to the development of gastrointestinal cancer. Thirteen percent of colorectal carcinomas are thought to be associated with a replication error (RER) or microsatellite instability phenotype. Subsequent inactivation of T 3RII and... [Pg.1231]


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See also in sourсe #XX -- [ Pg.55 ]




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