INDEX sensitization measurement

Minimum reportable concentration. The lower concentration limit for a method is usually measured by determining the detection limit. This is basically an instrument signal to noise ratio, and it does not include calibration effects. At low concentrations the calibration process often has a major adverse effect on precision. Detection limits are useful for comparing the inherent sensitivity of methods, but they are not realistic indexes of measurable concentrations in routine analysis. 

The index is easily calculated and depends mainly on chronic toxicity tests associated with a sensitive measurement endpoint chosen to be the EC 10 (concentration incurring a 10% effect). It can be used as a regulatory criterion that is more protective of aquatic ecosystems than those based on a single acute toxicity test. 

Figure 12 reveals that when VAi = a VBi(Vi) (a is a constant and i- 0) the Petke MEP-SI is an even more sensitive measure of similarity than the Hodgkin index. This is true particularly in the region ae[- 1, 1] where MEP-SI(P) varies linearly with a. The Sis defined by Eqs. (17), (18) and (22) may be called cumulative indices since in each case the SI is computed by accumulating products of MEP values for a number of grid points [116]. 

The proposed normalized dispersion index (NDI) has been shown to be a sensitive measure of the "goodness" of particle dispersion in space. An NDI value of. 142 was shown to be a critical level of dispersion that demarcates two totally different types of crazing behavior in HIPS. 

The development of an insensitive controller can of course be accomplished by repetitive simulations, but this by itself is an inefficient and usually impractical approach. The design of such a controller using standard linear optimal control methods has not proven to be fruitful as yet, since inclusion of sensitivity measures in the performance index does not yield to a closed form solution (57), (58). There is a need for improved methods which can realize desired sensitivity characteristics as well as high performance without resorting to extensive interactive calculations Davison (59) has recently suggested one such approach. 

Where R is the reflectivity and d is the thickness. Very accurate values of R and T are needed when the absorptance, (id, is small. The technique of photothermal deflection spectroscopy (PDS) overcomes this problem by measuring the heat absorbed in the film, which is proportional to ad when ad 1. A laser beam passing just above the surface is deflected by the thermal change in refractive index of a liquid in which the sample is immersed. Another sensitive measurement of ad is from the speetral dependence of the photoconductivity. The constant photocurrent method (CPM) uses a background illumination to ensure that the recombination lifetime does not depend on the photon energy and intensity of the illumination. Both techniques are capable of measuring ad down to values of about 10 and provide a very sensitive measure of the absorption coefficient of thin films. 

The refractive index sensitivity affects gradient analysis and should be checked by measuring the absorbance when the cell is filled with methanol (n = 1.329) and cyclohexane (n = 1.427) at 270 nm. 

Refractive index detectors continuously monitor the difference in bulk RI of the mobile phase and that of a reference mobile phase containing no solute. As such, RI is a bulk property detector. Unlike UV detectors, RI detectors are highly sensitive to temperature fluctuations and somewhat sensitive to flow rate fluctuations. Temperature should be maintained within 0.001°C for high-sensitivity measurements. Noise equivalent concentration for RI is IQ- g/ml. ... 

Chong J, Shum P, Haryono H, Yohana A, Rao M, Lu C, Zhu Y (2004) Measurements of refractive index sensitivity using long-period grating refractometer. Opt Commun 229 65-69... 

In this section attention is focused on the refractivity volume. In order to calculate this quantity, it is necessary to have refractive index and density data. The density can of course be calculated from X-ray data and the unit ceU contents. However, X-ray data are not a requirement. The measured density together with refractive index data are sufficient, and both types of measurements (7J9) can frequently be made using the microscope ). Examination of crystals using a petrographic microscope is an old technique, but it appears to have fallen out of favor with inorganic and structural chemists. Thus, it is not widely known that the molar refractivity of fluoride complexes is a sensitive measure of their composition. 

This is a measure of simple motor speed. The participant is instructed to tap a key with the index finger as rapidly as possible for 10 s. Three trials are obtained for each hand and the mean is used for the analyses. This is a sensitive measure of CNS motor dysfunction. 

Index duration Measuring the price sensitivity to change of reference rate only ... 

The method of SPR is generally used for sensitive measurement of variations in the refractive index of the medium immediately surrounding the metal film. For example, if an antibody is bound to or absorbed into the metal surface, a noticeable change in the resonance angle can be readily observed because of the change of the refraction index at the surface, assuming all other parameters are kept... 

Knowing the optical properties and the orientation of the mica layers, a conversion chart can be calculated to determine the separation D from the measured A, as shown in Fig. 3.17. The conversion chart is calculated from the equations of a three-layer interferometer [39], possibly modified to include birefringence of the mica layers [40]. As a general rule, A is always shifted towards smaller values with decreasing D. As X depends also on the index n, measurements for two or more transmission wavelengths are sufficient to calculate D and n at the same time. To do that, one has to invert a set of interferometric equations giving A as a function of D and n. The resulting tjrpical resolution in separation D is about 0.2 nm and the sensitivity to n is about 0.01. We stress however that the equations are nonlinear and the solutions may become unreliable for some D, due to an instability with respect to the error in A (see Fig. 3.21 for an example). 

The first term of the Fourier transform essentially defines a baseline shift of very broad bandwidth and is a very sensitive measure of the absorbance due to Ught scattering. A plot of the first Fourier transform term versus amount of compound added works much better as an index of precipitation than a simple plot of absorbance versus amount of compound added. The UV absorbance method is also somewhat dependent on the instrumental design and works best when there is a large distance between the sample cell and the UV detector. 

Surface Plasmon Resonance Sensors, Fig. 4 Sample sensitivity measurements using solutions of different refractive indices made using the nanohole SPR device shown in Fig. 2. Transmission spectra were obtained through a 450 nm periodicity array for the cases of pure water, sucrose solutions with increasing refractive index,... 

There are other methods that predict reactivity more reliably than the oxygen balance method. These methods, however, require the use of data generated by measurements. Stull devised a relatively simple Reaction Hazard Index or RHI that used both kinetic and thermodynamic data measurements. This index is a graphic model (nomagraph) that uses the Arrhenius activation energy and the decomposition temperature The latter term is the maximum adiabatic temperature reached by the products of a decomposition reaction. If data are available or can be measured, the RHI may be a very useful method to predict reactivity. Coffee described a method that predicts the explosive potential of a compound using thermal stability (measured), impact sensitivity (measured), and the heat of reaction (calculated). Compounds found to be thermally unstable and sensitive to impact were explosive. 

Fig. 4.31. Laser interferometer for sensitive measurements of local variations of the index of refraction in extended samples, for example, in air above a candle flame...

A foil irradiation method was evaluated for its ability to verify the neutron energy spectrum in the assembly. In thb method a spectral index was measured using indium foil. The spectral index was the ratio of the rate of the " In(n, y) reaction (sensitive to low-energy neutrons) to the rate of the In(n, n ) reaction (sensitive to high-energy neutrons). The ratio of the gamma-ray intensities from the products of these reactions comprise the experimental data. This spectral index was able to detect the presence of a 0.64-cm-thick, S.D8-cm-high polyethylene column 10 to 15 cm away from the indium foil. 

The refractive index detector measures both polymers simultaneously see Figure 3.22 (90). Flowever, the sensitivity to each polymer differs, being a function of the difference between each polymer refractive index and the solvent. The values are summarized in Table 3.13 (90). This particular system is nearly three times more sensitive to the polystyrene. 

The above results are all in concurrence with our intuitive expectations and merely quantify what we already know or can guess. However, for more complex structures, the reliability index and the associated sensitivity measures provide valuable insight into the behavior of structures and the significance of various uncertainties, thus providing a resourceful means for rational decision making in the design or analysis stage. 

The significance of uncertainty in the load can be observed in Table 4, which lists the values of the reliability index, failure probability, linearization point, and scaled sensitivity measures with respect to the means and standard deviations. The results are for both deterministic and random values of the load and for r= 1, p=0, and a = 0.25. For the processes and Gi, the linearization point listed is for element 32 and the sensitivities are with respect to the process means and standard deviations rather than those of the individual element. It is interesting to note that for the selected values of the parameters the reliability is more sensitive to the mean of Ki than the mean of /Tj. This is attributed to the random fluctuations in Ki and the cancellation of the sensitivities arising from the various elements of the plate. Such cancellations do not occur for the sensitivities with respect to the standard deviation of the process, as they are negative for all elements. Hence, the reliability index is more sensitive to the standard deviations of the processes and Gj than the standard deviations of the variables K2 and G2, respectively. 

In order to measure the particulate fouling potential of feed water, Schippers and Verdouw [48] proposed a modified fouling index (MFI) by using a microfiltration membrane as a quick test of the feed water quality. They further improved the accuracy of the index and developed a new index of MFI-UF by using ultrafiltration membranes to increase the index sensitivity to the presence of colloidal particles for constant pressure operation [49, 50] and constant flux operation [51]. 

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