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Electrical resistivity Chemical Analysis

Testing. Various test methods are provided by ASTM (16). These iaclude pigment tests of importance such as chemical analysis, presence of oversize particles, oil absorption, particle size distribution, degree of dispersion, presence of soluble components, etc. Numerous tests are also given by ASTM for the properties of filled and unfilled polymers. These iaclude, for example, such properties as impact resistance, stiffness, viscosity, tear resistance, hardness, color, and electrical resistivity. [Pg.209]

Inhibitor control can be effected by conventional methods of chemical analysis, inspection of test specimens or by instrumentation. The application of instrumental methods is becoming of increasing importance particularly for large systems. The techniques are based on the linear (resistance) polarisation method and the use of electrical resistance probes. They have the advantage that readings from widely separated areas of the plant can be brought together at a central control point. (See Section 18.1.)... [Pg.783]

A relatively new arrangement for the study of the interfacial region is achieved by so-called emersed electrodes. This experimental technique developed by Hansen et al. consists of fully or partially removing the electrode from the solution at a constant electrical potential. This ex situ experiment (Fig. 9), usually called an emersion process, makes possible an analysis of an electrode in an ambient atmosphere or an ultrahigh vacuum (UHV). Research using modem surface analysis such as electron spectroscopy for chemical analysis (ESCA), electroreflectance, as well as surface resistance, electrical current, and in particular Volta potential measurements, have shown that the essential features (e.g., the charge on... [Pg.31]

The non-stoichiometry <5 of Cu2- O has been extensively studied by various methods such as chemical analysis of a quenched sample, thermogravimetry, electrical resistivity measurement, and coulometric titration, but the results obtained are not consistent. [Pg.74]

Samples were characterized by X-ray diffraction, magnetic susceptibility and chemical analysis with some results summarized in Table 1. The electrical resistivity measurements were made down to 80 K using a four-probe method. Raman scattering experiments used the excitation line A = 514.5 nm of an Ar+ laser in a quasi-backscattering geometry. The laser power of 5 mW was focused to a 0.1 mm diameter spot on the (010) surface. The averaged laser power density amounts to 6 105 W/m2 which is much less compared to earlier Raman studies in manganites [12-15],... [Pg.187]

Many different methods can be used to measure the degree of crosslinking within an epoxy specimen. These methods include chemical analysis and infrared and near infrared spectroscopy. They measure the extent to which the epoxy groups are consumed. Other methods are based on the measurements of properties that are directly or indirectly related to the extent and nature of crosslinks. These properties are the heat distortion temperature, glass transition temperature, hardness, electrical resistivity, degree of solvent swelling and dynamic mechanical properties, and thermal expansion rate. The methods of measurement are described in Chap. 20. [Pg.64]

The authors also measured the enthalpy change of the reaction between AgN03(cr) and a solution of sodium selenite with formation of crystalline silver selenite as verified by chemical analysis and X-ray diffraction. The calorimeter was calibrated by electrical resistance heating. The calorimetric data are evaluated in Table A-25. [Pg.466]

Several workers have attempted to rationalise the chemical isomer shifts observed at Au impurity nuclei in various metals with limited success [102, 103]. The most comprehensive set of data comes from Barrett et al. [104], who doped Pt into 20 metals. The shift correlates very approximately with the electronegativity of the host, and a crude interpretation is that electrons are transferred in v ing degrees to the 6j-shell of the gold. An estimate of bR/R — 1-9(6) X 10 was obtained. Additional evidence in favour of an increased 6. -population has come from a comparison of the shift and residual electrical resistivity of Au alloys with Cu, Ag, Pd, and Pt [105]. The pressure dependence up to 70-6 kbar of the chemical isomer shift in a gold foil at 4-2 K has been obtained and with detailed analysis leads to a value for bR/R of +l-5 X 10- [106]. [Pg.530]

Fransolet, E., Crine, M., Marchot, P, and Toye, D. (2005), Analysis of gas holdup in bubble columns with non-Newtonian fluid using electrical resistance tomography and dynamic gas disengagement technique, Chemical Engineering Science, 60 6118-6123. [Pg.282]

All electrochemical methods are based on the interaction of electrical energy and matter. The measurements are done in an electrochemical cell where the sample and at least two electrodes are placed. The electrochemical cell possesses a large variety of concentration-dependent physical characteristics that may be exploited for chemical analysis. The methods are mainly used in analysis of aqueous samples but are also applicable to nonaqueous solutions and gases. In most of the methods one concentration-dependent electrical parameter, like voltage, current, resistance, or charge, is measured while the others are kept constant or manipulated to receive the desired response that correlates to the sample composition. [Pg.3869]

There are many other techniques for measuring corrosion. Some of these may rely on chemical solution analysis or physical measurement of metal loss. One widely used additional technique is provided by ASTM G 96, Practice for On-Line Monitoring of Corrosion in Plant Equipment (Electrical and Electrochemical Methods). This guide covers two basic procedures. In one, a sample of the material, usually in the form of a continuous wire, is immersed into the environment of interest (liquid, air, solid, or multiphase). The electrical resistance through the wire is determined. As corrosion consumes the cross section of the wire, the resistance increases proportionately. The second procedure uses the polarization resistance technique described in ASTM G 59 to determine the corrosion rate in the environment. [Pg.210]


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