Systematic measurement

Rectification accounts for systematic measurement error. During rectification, measurements that are systematically in error are identified and discarded. Rectification can be done either cyclically or simultaneously with reconciliation, and either intuitively or algorithmically. Simple methods such as data validation and complicated methods using various statistical tests can be used to identify the presence of large systematic (gross) errors in the measurements. Coupled with successive elimination and addition, the measurements with the errors can be identified and discarded. No method is completely reliable. Plant-performance analysts must recognize that rectification is approximate, at best. Frequently, systematic errors go unnoticed, and some bias is likely in the adjusted measurements. 

Systematic Measurement Error Fourth, measurements are subject to unknown systematic errors. These result from worn instruments (e.g., eroded orifice plates, improper sampling, and other causes). While many of these might be identifiable, others require confidence in all other measurements and, occasionally, the model in order to identify and evaluate. Therefore, many systematic errors go unnoticed. 

We have recently performed systematical measurements of the intrinsic viscosity of acrylamide-acrylic acid copolymers for large ranges of r and a, in the presence of CaCl2(26). Our results show that the empirical relation (14) can be extended to the case of divalent cations by using the value of 7 given in relation (15). It should then possible to predict the variation of intrinsic viscosity at infinite dilution, but at finite concentration the formation of aggregates makes difficult the determination of the Huggins constant. 

The above-mentioned early supplementation studies with xanthophylls did not measure the changes in MPOD associated with supplementation probably because an easy-to-use technique for its noninvasive measurement in the human retina eye was not available at that time. The first apparatus for this purpose had been described in 1953 by deVries et al. (1953) and it is only since the 1970s that publications can be found that report on systematic measurements of MPOD in the human retina. 

The first systematic measurements of the reactions of ions with molecules in the gas phase were initiated largely by workers associated with analytical mass spectrometry.4-6 It was the rapidly expanding area of ion-molecule reactions which led to the origin of Gas-Phase Ion Chemistry as a distinct field.7 The discovery that ion-molecule equilibria in the gas phase can be determined by mass spectrometric techniques8 led to an explosion of thermochemical measurements based on determination of equilibria by a variety of techniques.9 Significantly, for the first time, information could be obtained on the thermochemistry of reactions which had solution counterparts of paramount importance such as acidities and basicities. These were obtained from proton transfer equilibria such as,... 

Laverman and coworkers have reported activation parameters for the aqueous solution reactions of NO with the iron(II) and iron(III) complexes of the water soluble porphyrins TPPS andTMPS (21). These studies involved systematic measurements to determine on and kQ as functions of temperature (298—318 K) and hydrostatic pressure (0.1—250 MPa) to determine values of AH, AS and AV for the on and off reactions of the ferri-heme models and for the on reactions of the ferro-heme models (Table II). Figure 2 illustrates hydrostatic pressure effects on kOTL and kQff for Fem(TPPS). 

Systematic measurements of stress and strain can be made and the results plotted as a rheogram. If our material behaves in a simple manner - and it is surprising how many materials do, especially if the strains (or stresses) are not too large - we find a linear dependence of stress on strain and we say our material obeys Hooke s law, i. e. our material is Hookean. This statement implies that the material is isotropic and that the pressure in the material is uniform. This latter point will not worry us if our material is incompressible but can be important if this is not the case. 

It is probable that numerous interfacial parameters are involved (surface tension, spontaneous curvature, Gibbs elasticity, surface forces) and differ from one system to the other, according the nature of the surfactants and of the dispersed phase. Only systematic measurements of > will allow going beyond empirics. Besides the numerous fundamental questions, it is also necessary to measure practical reason, which is predicting the emulsion lifetime. This remains a serious challenge for anyone working in the field of emulsions because of the polydisperse and complex evolution of the droplet size distribution. Finally, it is clear that the mean-field approaches adopted to measure > are acceptable as long as the droplet polydispersity remains quite low (P < 50%) and that more elaborate models are required for very polydisperse systems to account for the spatial fiuctuations in the droplet distribution. 

The measurement bias is an estimate of a systematic measurement error. 

The dorsal skin fold window model allows direct observation of tumor microvasculature (11). This model also permits longitudinal assessment of the tumor vascular response to therapy. An accurate systematic measurement of tumor blood vessels in the window model is the linear summation of blood vessels using Optimas software. This approach corrects for vascular dilation and hemorrhage. Quantification of red... 

Biological and environmental properties are generally not systematically measured and tabulated, until the recent compilation activities sponsored by the U.S. EPA, and by the Occupational Safety and Flealth Administration (OSHA). Properties such as prices and concentrations regarded as safe are changeable and can only be found in newspapers and journals, such as the New York Times and Chemical Marketing Reporter. 

Assumptions (i) and (ii) justify the model in the form (3.2), with an additive error as the only random variable. By (iii) we assume that the model is correct and there are no systematic measurement errors, i.e.,... 

Similar calculations would be possible with the system Al(Cl04)3 in DMSO-H2O studied by Olander, Marianelli, and Larson (63), but the actual experimental results are not available. The Mg2+ system in methanol-water has been studied several times (64, 65) and appears to be more complex in the interpretation of the spectra obtained. Again detailed systematic measurements at one temperature and a range of solvent compositions are not available. 

Useful quantitation of heat q as a quantity of energy can be traced to the studies of Joseph Black around 1803. Black recognized that different substances vary in their capacity to absorb heat, and he undertook systematic measurements of the heat capacity C (the ratio of heat absorbed to temperature increase) for many substances. He recognized that a fixed quantity of any pure substance (e.g., 1 g of water) has a unique value of C, which can be chosen as a calorimetric standard for defining quantity of heat in a convenient way. In this manner, he introduced the calorie as a unit of heat ... 

Fig. 54 shows some first systematic measurements by Bantle et al.207,209), who changed the delay time by factors of 1 2 4 8 the suggested optimum condition for a recording of the full correlation time corresponds to a value of 4, i.e. the TCF has decayed here to e 2 of the original value at channel 80220. Evidently, the qz dependence can in these four cases be represented by... 

The first measurements of microwave ionization in any atom were carried out with a fast beam of H by Bayfield and Koch1, who investigated the ionization of a band of approximately five n states centered at n = 65. Using microwave and rf fields with frequencies of 9.9 GHz, 1.5 GHz, and 30 MHz, to ionize the atoms they found that the same field was required at 30 MHz and 1.5 GHz to ionize the atoms, but that a smaller field was required at 9.9 GHz. The measurements showed that at n = 65 frequencies up to 1.5 GHz are identical to a static field. Later, more systematic measurements have confirmed the initial measurements and have allowed significant refinements of our understanding. In Fig. 10.16 we show the ionization threshold fields (in this case the field at which there is 10% ionization) of H in a 9.9 GHz field.21 The ionization fields are plotted as n4E vs n3a>, and they bring out two factors. First, at low frequencies the field required is l/9n4, the static field required to ionize the red n Stark state of m n. Second, as shown by the scaling of the horizontal axis, the required field drops below l/9n4 as the microwave frequency approaches the interval between adjacent n states, 1 In3. 

Foltz et al.36 have made systematic measurements of electron collisions with laser excited Na nd Ryderg atoms using an apparatus similar to the one shown in Fig. 13.1 but differing in two respects. First, an electron beam is used instead of an ion beam, and second, a magnetic shield encloses the electron beam and interaction region. 

Modern diffractometers are computer-driven and almost completely automated. They can, with some minimal (but important) intervention by the operator, search for reflections and determine unit-cell dimensions and then systematically measure the intensities of all accessible reflections. 

One of the obstacles in this aim is the lack of experimental thermodynamic data for activity coefficients in ionic liquids, which could be a basis for such solvent selection. In the past years several groups have started to measure such data however, there is a lack of data because the number of suitable anions and cations, and even more the number of ionic liquids, are rapidly increasing compared to the rate (or speed) of measurements. Reliable inter- and extrapolation schemes and group contribution methods are still missing. Thus the search for an appropriate ionic liquid for a certain task can, at present, only be made randomly or by systematic measurements. 

ADEOS An improved, satellite Earth-observing system equipped with modernized radiometer of the visible and near-IR intervals (AYNIR), ocean color and temperature scanner (OCTS), and radiometer POLDER to carry out global systematic measurements of polarization and spectral characteristics of solar radiation reflected by the Earth-atmosphere system. The satellite ADEOS-2/ Midori-2 was launched on December 14, 2002 by the Japan Space Agency and is an ideal means of global monitoring. 

The number of vapour pressure studies of the tribromides is significantly less. Gietmann et al. (1996) systematically measured the vaporization of the lanthanide bromides using mass spectrometry, showing the importance of the dimeric molecules in the vapour. For the light lanthanide tribromides (La, Ce, Nd) the fraction of dimers is around 0.01, but for TbBr3 it is 0.03,... 

Alternatively, one can measure these ionization cross-sections and use them in much the same way as k-factors [43] are used in EDX microanalysis. Two systematic measurements, one for K, L edges [44] and the other for M4,5 edges [45] are reported in the literature. However, experimentally measured cross-sections show large variations [34]. To overcome these difficulties, it is necessary to prepare standards of well known stoichiometry and to measure their thickness accurately. Finally, some of the measurements reported in the literature [33] have been made with large collection angles (-100 mrad) and should be used with caution as they could be erroneous due to lens aberration effects. 

Organic and inorganic intercalators not covalently attached to oligonucleotides were first reported for study of CT in DNA. These experiments provide little information, because of the lack of an accurate measurement of the distance between the D and A and the concern for pairing of the intercalators. A significant experimental improvement came with DNA assays bearing covalently linked intercalators. By use of these systems systematic measurement of distance dependence and base sequence dependence was possible. These experiments led to three important observations ... 

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