Absolute accuracy

Sample volume Precision Accuracy Absolute detection limit Relative detection limit Organic solvent consumption Equipment cost Cost of supplies Manual labor Automation Preparative... 

Today, there an established software tool set does exist for the primary task, the calculation of modes and the description of field propagation. Approaches based on the finite element method (FEM) and finite differences (FD) are popular since long and can be applied to complex problems . The wave matching method, Green functions approaches, and many more schemes are used. But, as a matter of fact, the more dominant numerical methods are, the more the user has to scrutinize the results from the physical point of view. Recent mathematical methods, which can control accuracy absolutely - at least if the problem is well posed, help the design engineer with this. ... 

Figure 5.7 Incipient temperature accuracy (absolute) for uninhibited hydrate data for...

Although one can estimate changes in radical concentration with considerable accuracy, absolute concentrations are very difficult to measure precisely. This arises, at least in part, because in order to achieve high sensitivity, the first or even the second derivative of the... 

Once this procedure is complete, the user has a permanent record of Raman shift accuracy, absolute instrument response, and instrument response function for a given experimental session. Over time, these periodic records provide an indication of instrumental drift and performance changes. In addition, they may be checked at a future date if a particular sample appears to deviate from expected behavior. If the instrument was at fault, the daily qualification spectra may provide insight into the origin of the deviation. 

Accuracy (absolute recovery after spiking) between 95% and 105%. 

The accurate and absolute measurement of the distance, D, between the surfaces is central to the SFA teclmique. In a typical experiment, the SFA controls the base position, z, of the spring and simultaneously measures D, while the spring constant, k, is a known quantity. Ideally, the simple relationship A F(D) = IcA (D-z ) applies. Since surface forces are of limited range, one can set F(D = go) = 0 to obtain an absolute scale for the force. Furthennore, SF(D = cc)/8D 0 so that one can readily obtain a calibration of the distance control at large distances relying on an accurate measurement of D. Therefore, D and F are obtained at high accuracy to yield F(D), the so-called force versus distance cur >e. 

Set this threshold Lo a small positive constant (the default value is 10 Hartrcc), Tli is tli resh old is used by HyperCh cm to igu ore all two-cicetron repulsion in tegrals with an absolute value less th an th is value. Tli is option controls the performance of the SCF itera-lious and the accuracy of the wave function and energies since it can decrease the number of ealeulatcd Iwo-elcclrou integrals. 

The accuracy of these methods is tested by finding the mean absolute error between the computed and experimental free energies of solvation. The SM4 method does well for neutral molecules in alkane solvents with a mean absolute error of 0.3 kcal/mol. For neutral molecules, the SM5 methods do very well with mean absolute errors in the 0.3 to 0.6 kcal/mol range, depending on the method and solvent. For ions, the SMI method seems to be most accurate with... 

Accuracy is a measure of how close a measure of central tendency is to the true, or expected value, Accuracy is usually expressed as either an absolute error... 

The accuracy of a standardization depends on the quality of the reagents and glassware used to prepare standards. For example, in an acid-base titration, the amount of analyte is related to the absolute amount of titrant used in the analysis by the stoichiometry of the chemical reaction between the analyte and the titrant. The amount of titrant used is the product of the signal (which is the volume of titrant) and the titrant s concentration. Thus, the accuracy of a titrimetric analysis can be no better than the accuracy to which the titrant s concentration is known. 

As normally used in the process industries, the sensitivity and percentage of span accuracy of these thermometers are generally the equal of those of other temperature-measuring instruments. Sensitivity and absolute accuracy are not the equal of those of short-span electrical instruments used in connection with resistance-thermometer bulbs. Also, the maximum temperature is somewhat limited. 

Required Sensitivity This is difficult to establish a priori. It is important to recognize that no matter the sophistication, the model will not be an absolute representation of the unit. The confidence in the model is compromised by the parameter estimates that, in theoiy, represent a limitation in the equipment performance but actually embody a host of limitations. Three principal limitations affecting the accuracy of model parameters are ... 

The known models for describing retention factor in whole variable space ar e based on three-phase model and containing from three to six par ameters and variety combinations of two independent factors (micelle concentration, volume fraction of organic modifier). When the retention models are comparing or the accuracy of fitting establishing, the closeness of correlation coefficient to 1 and the sum of the squared residuals or the sum of absolute deviations and their relative values is taken into account. A number of problems ar e appear in this case ... 

The advantage of using relative risk results is that you can decide on the best way to improve safety at a facility without having to defend the absolute accuracy of the results. Relative results are also much less likely to be misinterpreted by people unfamiliar with QRA. The disadvantage of using relative results is that they, by definition, cannot give direct advice... 

The accuracy of absolute risk results depends on (1) whether all the significant contributors to risk have been analyzed, (2) the realism of the mathematical models used to predict failure characteristics and accident phenomena, and (3) the statistical uncertainty associated with the various input data. The achievable accuracy of absolute risk results is very dependent on the type of hazard being analyzed. In studies where the dominant risk contributors can be calibrated with ample historical data (e.g., the risk of an engine failure causing an airplane crash), the uncertainty can be reduced to a few percent. However, many authors of published studies and other expert practitioners have recognized that uncertainties can be greater than 1 to 2 orders of magnitude in studies whose major contributors are rare, catastrophic events. 

Eortunately, a 3D model does not have to be absolutely perfect to be helpful in biology, as demonstrated by the applications listed above. However, the type of question that can be addressed with a particular model does depend on the model s accuracy. At the low end of the accuracy spectrum, there are models that are based on less than 25% sequence identity and have sometimes less than 50% of their atoms within 3.5 A of their correct positions. However, such models still have the correct fold, and even knowing only the fold of a protein is frequently sufficient to predict its approximate biochemical function. More specifically, only nine out of 80 fold families known in 1994 contained proteins (domains) that were not in the same functional class, although 32% of all protein structures belonged to one of the nine superfolds [229]. Models in this low range of accuracy combined with model evaluation can be used for confirming or rejecting a match between remotely related proteins [9,58]. 

The vane can be used for both average wind direction and the fluctuation statistic determined over hourly intervals. The vane should have a distance constant of less than 5 m and a damping ratio greater than or equal to 0.4 to have a proper response. Relative accuracy should be 1° and absolute accuracy should be 5°. In order to estimate accurately, the direction should be sampled at intervals of 1-5 sec. This can best be accom-... 

Control systems for process compressors become an absolute necese whenever deviations from a single operating point occur in the process system. These systems consist of a mechanism that can sense performance and, by making a calculation, adjust the process controls with satisfactory speed, accuracy, and stability. 

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