Property to be measured

A cover survey requires the location of the rebars to be measured in there dimensions, i.e. their position with regard to each other and the plane of the surface (X,Y) and depth from the surface (Z). If construction drawings are not available then it may be necessary to measure the rebar diameter as well as its location. 

One if the few standards for cover meters is BS1881, Part 204. This refers to the measurement on a single rebar and is more concerned with the meter than taking a cover survey. Alldred (1993) discusses cover meter accuracy when several rebars are close together and suggests that different types of head are more accurate in different conditions. The smaller heads are better for resolving congested rebars. 

Very negative potentials can be found in saturated conditions where there is no oxygen to form a passive layer but with no oxygen there can be no corrosion. This shows the weakness of potential measurements. They measure the thermodynamics of the corrosion, not the rate of corrosion. Corrosion potentials can be misleading. Their interpretation is based on empirical observation, not rigorously accurate scientific theory. The problem is that the potential is not 

The half cell potential measurement gives an indication of the corrosion risk of the steel. The measurement is linked by empirical comparisons to the probability of corrosion. 

The equipment used is a standard half cell. Silver/silver chloride (Ag/AgCl) and mercure/mercure oxide (Hg/HgO) are recommended Copper/copper sulphate (CSE) cells are also used but are not recommended because of the maintenance needs, the risk of contamination of the cell, the difficulty of use in all orientations and the leakage of copper sulphate. 

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Central to all SPMs (or local probe methods , or local proximal probes as they are sometimes called) is the presence of a tip or sensor, typically of less than 100 mn radius, that is rastered in close proximity to—or in contact with—tire sample s surface. This set-up enables a particular physical property to be measured and imaged over the scaimed area. Crucial to the development of this family of teclmiques were both the ready availability of piezoelements, with which the probe can be rastered with subnanometre precision, and the highly developed computers and stable electronics of the 1980s, without which the operation of SPMs as we know them would not have been possible. 

Remaining terms to right of the bracket relate to properties to be measured within the matrix. The factor/is adjusted from 0 to 1 in relationship to the purpose of testing. A low value of/is indicated for scarce elements such as precious metals in electronic-source scrap. Moisture content has a high/value. The factor g is adjusted from 0 to... 

A fairly direct way of observing galvanic effects, which also permits changes in mechanical properties to be measured, involves the preparation of a composite specimen formed by attaching a strip, or strips, of one metal to a panel of another one. Tensile test specimens that include the areas of galvanic action can be cut from these panels after exposure, as shown in Fig. 19.30. 

It is clear that fires of type (i) will not go through stages 3-5, fires of type (ii) will skip stages 4 and 5, and fires of type (iii) will not reach stage 5, before decaying. These considerations are important because they will be an essential tool in deciding the properties to be measured for estimating fire risk or fire hazard. 

Methods which permit the effect on specific molecular properties to be measured are suited to this purpose. Thus, spectroscopic methods are primarily to be considered. 

Property to be Measured ASTM Test Standard Specimen Dimensions Test Molding Sample Weight per Molding (grams)... 

The calibration methods most frequently used to relate the property to be measured to the analytical signals acquired in NIR spectroscopy are MLR,59 60 principal component regression (PCR)61 and partial least-squares regression (PLSR).61 Most of the earliest quantitative applications of NIR spectroscopy were based on MLR because spectra were then recorded on filter instruments, which afforded measurements at a relatively small number of discrete wavelengths only. However, applications involving PCR and PLSR... 

Test portion quantity of coal that is representative of the analysis sample and sufficient to obtain a single test result for the property or properties to be measured. 

The computations entailed in determining the average statistical diameters just discussed are given in Table 7. The computations are for a distribution of sizes given in Table 4. It is obvious from this table that values of dav are about a third smaller than. the next largest statistical diameter dw. The use of a correct diameter giving proper weight to the physical property to be measured is apparent. 

Wavelength was stepped from 200 to 650 nm in 10 nm increments. The 15-second dwell time at each wavelength was sufficient for a change in film properties to be measured without appreciably cross-linking the film the entire spectral response experiment cross-linked the film by less than 20%. 

A much broader range of applications have detection methods, with which one measures the change in a certain physical property of the eluent (e.g. conductance) that is due to the solute ion elution. A sufficient difference between eluent and solute ions is a prerequisite in the measuring values of this property. Most of the detection methods applied to ion chromatography are based on this technique. For the ensuing discussion a further subdivision into direct and indirect methods is made. Direct detection methods are those, in which eluent ions exhibit a much smaller value than solute ions for the property to be measured. On the other hand, detection methods are called indirect, if eluent ions exhibit a much higher value for the property to be measured than do solute ions. 

To measure physical properties reliably, the following must occur The measuring instruments must be carefully selected and the instrument must be properly installed and operated. Factors to be considered in the selection process include the range of property to be measured, accuracy and reproducibility of the readings desired, ease of installation and servicing, and both capital and expected maintenance costs. 

The system is first brought to equilibrium in the presence of certain macroscopic constraints so that the property to be measured, (A(x, t))>o, is constant in time but depends on position. This quantity (A(r, t))>o is the ensemble-average of a property A in the ensemble defined by the constraints. 

Electronic noses and tongues are arrays of sensors used to characterize complex samples, with the former being arrays of gas sensors while the latter are composed of liquid sensors [1]. These devices are composed of a chemical sensing system and a pattern recognition (PR) system [usually an artificial neural network (ANN)]. The array sensing system allows different properties to be measured simultaneously [2], Each chemical, which reaches the sensor array, will produce a characteristic pattern and therefore a database of patterns will be built up for a series of chemicals [2],... 

As explained earlier, due to the combination of components possible, and the final processing by the fabricator, it is important that the material tested be fully characterized. The properties to be measured include the following. 

The strength and stiffness of a composite material are the properties that arc most generally recognized as being anisotropic. The test methods frequently require the properties to be measured in two mutually perpendicular directions depending on the material being evaluated,... 

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