Intercept method

Determine exposure via groundwater define contaminant plume for evaluation of interception methods... 

The advantage of the slope/intercept method is that it is rather simple to implement, in that it only requires two parameters for each slave instrument. In addition, it does not require the designation of specific transfer standards to define the transfer. However, it requires that the same subset of calibration samples be analyzed by all of the slave instruments, which can take a while if several slave instruments are involved. Furthermore, it assumes that the sources of inter-instrament response variability are completely linear in nature. Therefore, it might not be optimal if significant nonlinear differences, such as wavelength axis shifts between analyzers, are present. A final limitation is that it assumes that the nature of the inter-instrument variability is constant over all wavelength ranges, and over all possible sample compositions. 

Steady-State Kinetics, There are two electrochemical methods for determination of the steady-state rate of an electrochemical reaction at the mixed potential. In the first method (the intercept method) the rate is determined as the current coordinate of the intersection of the high overpotential polarization curves for the partial cathodic and anodic processes, measured from the rest potential. In the second method (the low-overpotential method) the rate is determined from the low-overpotential polarization data for partial cathodic and anodic processes, measured from the mixed potential. The first method was illustrated in Figures 8.3 and 8.4. The second method is discussed briefly here. Typical current—potential curves in the vicinity of the mixed potential for the electroless copper deposition (average of six trials) are shown in Figure 8.13. The rate of deposition may be calculated from these curves using the Le Roy equation (29,30) ... 

Fig. 2.1 Methods of estimating d, the projected area diameter (a) image shearing method [after Heywood (H6)] (b) statistical intercept method [after Martin et al. (Ml)].

The linear regression method, or slope-intercept method (Zou, 1997), for whole-rock residues can only be applied to modal batch melting. For elements a (highly incompatible) and b (not-so-highly incompatible), their concentrations in the residue during modal batch melting, and, respectively, are given by... 

The PDS method is a multivariate answer to the univariate slope/intercept method.73 75 In this method, the responses of a set of transfer standards are obtained on both the master and the slave instruments (thus producing Xm and Xs, respectively). It is then desired to obtain a transformation matrix F such that the spectra obtained on the slave instrument can be transformed into spectra that would have been obtained on the master instrument ... 

Table 7.6 shows the chemical composition of SA213 316L stainless steel. The microstructure was determined to be an equiaxed structure with average grain size of 50 pm, measured by the mean intercept method. 

Turner, R. C. 1959. An investigation of the intercept method for determining the proportion of dolomite and calcite in mixtures of the two. I. Theoretical aspects of the rate of solution of dolomite when a number of crystals are present. Can. J. Soil Set. 40 219—231. 

Macheras P, Symillides M, Reppas C. An improved intercept method for the assessment of absorption rate in bioequivalence studies. Pharm Res 1996 13 1753-1756. 

The photosensitized oxidations in solution for determination of ft by the slope-intercept method were carried out in a constant temperature bath with light from a 250-watt projector lamp with a UV-cutoff filter. Oxygen uptake was monitored with a conventional mercury burette. Polymer films also were irradiated with the same lamp containing a Coming CS 3-69 filter. 

Values of p determined by the various techniques are summarized in Table II. A plot of the oxygen-uptake data and /3-values obtained by the slope-intercept method (21) appear in Figure 3. The reactivity of ds-3-hexane (ft 0.6 0.2M) was found to be about a factor of four less than that of ds-1,4-poly butadiene (p 2.3 0.2 M), whereas 1,4-polyisoprene (p 0.16 0.05M) is almost comparable in reactivity to its model olefin 3-methyl-3-hexene 0.13 0.Q4M). 

Van der Weij introduced the intercept method (see Sect. 3.3.2) and calculated the velocity (Transportgeschwindigkeit) of the auxin stream and its intensity (Transportintensitat), i.e., the amount of auxin passing the cross-section of... 

In spite of the uncertainties, difficulties, and complications mentioned so far and to be considered further below (see Sect. 3.3.3), the results obtained are generally believed to reflect and describe the properties of the hormone transport systems in intact plants. This belief is supported by results obtained with other methods which, at least partly, confirm the estimations derived from the intercept method. 

Similar conclusions have been drawn from studies of " C-IAA transport in Pisum internodes (Kaldewey et al. 1974) and Citrullus hypocotyls (Kaldewey et al. 1977), as affected by water stress and transport inhibitors, respectively. Water stress, as well as the inhibitor lycoricidinol, drastically decreased the transport density, as estimated by the intercept method, although the total amount of mobile auxin emerging ftom the basal cut surfaces of subsections after transport periods of 4 to 5 h increased or was only slightly decreased. Further, both treatments caused a higher portion of total... 

Short-term application of auxin to the apical cut surface of coleoptile sections, combined with an estimation of auxin accumulation with time in basal receivers which were replaced at brief intervals, was demonstrated by van der Weij (1932, p442ff) to be a means of calculating transport velocity. He observed that the auxin export rate (i.e., the transport intensity) increased initially to a maximum and then decreased. He assumed that the arrival time of the peak of transport intensity was the period of time needed by the auxin stream to traverse the segment. The velocity thus estimated (8mmh" ) was similar to the values of about 10mmh obtained with the intercept method. When labeled hormones became available, such pulse experiments were refined and modified. The duration of the pulse application could be reduced to 60 s (Shen-Miller 1973 a, b) and the receivers could be changed with great frequency to improve the estimation of the peak. 

Hertel (1962) and Hertel and Leopold (1963) were the first to use the pulse-chase method with " C-IAA and they observed that, in corn coleoptiles, the speed of the auxin wave was equal to the transport velocity as measured by the intercept method (Fig. 3.2A). The wave of NAA was shown to move... 

Sheldrake (1973 a) demonstrated by separation of the stem tissues of Nico-tiana internodes that the great majority of the strongly basipetal auxin transport took place in cells of the internal phloem and in cells close to the cambium. Very small amounts were transported in bark and pith preparations and none in xylem tissues. Using the intercept method of van der Weij (1932), he estimated velocities of about 5 mm h for the transport of l- C-IAA in complete stem sections, in inner tissue segments containing the internal phloem, and in xylem + cambium + bark section. The transport densities were similar to each other in the two latter preparations. Lower transport densities were found in the bark and in exclusively pith sections having transport velocities of 3.8 and 3.1 mm h S respectively. In all cases, however, a small amount of radioactivity was found in basal receivers considerably in advance of the time intercepts calculated from the linear parts of the auxin arrival curves (Fig. 3.3). Thus, even in homogenous tissues, auxin molecules appear to move at different velocities. 

By use of the intercept method of van der Weij (1932) the transport velocities in sunflower hypocotyl sections (Fig. 3.4), as estimated from the intersections with the time axis of the extrapolated linear regression lines, amount to 5.9 mm h" and 3.7 mm h at the higher and lower donor concentrations, respectively. Similar estimated relationships between donor concentration and transport velocity estimations have been found for basipetal lAA transport in Coleus stems (Naqvi 1963), Zea coleoptiles (Naqvi and Gordon 1964, Naqvi 1976), and Avena coleoptiles (Newman 1963, 1970) and may be deduced from the shape of the arrival curves derived mathematically by Newman (1974) from his experimental data. On the other hand, velocities estimated by the intercept method have been reported not to be significantly different at different auxin concentrations in the donor, though the calculated values tended to be higher at increased donor concentration (e.g., van der Weij 1932 in Avena coleoptiles ... 

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