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Measurement method

Ta b I e 2.1 Testing methods for various aging criteria Che = chemical changes, lnd = induction period, Sur = surfaoe property. Col = ooloring, Cha = chain cleavage, cross-linking, [Pg.147]

Mor = morphology, Pla = plasticity, embrittlement. Tern = temperature stability, glass transition. Pen = penetration depth + = good aging criterion, 0 = poor aging criterion [ 152] [Pg.147]

Physical-chemical methods can provide locally differentiated statements about damage, in particular about surface damage that depend on the point of measurement and/or sample removal. Physical-chemical measurement methods have shown to achieve high reliability in the evaluation of similar plastics as long as the plastics differ only in regard to stabilizers and pigments [152]. [Pg.147]

By contrast, mechanical properties often lack a generally quantifiable relationship with surface damage however, they are important data for actual service. [Pg.147]

It must be noted that aging criteria are not equally suitable for all plastics due to the basic differences in plastic materials. An aging test generally proves to be the more suitable, the more specific it is for the fundamental process of aging examined, Table 2.1 [152]. [Pg.147]

The use of a radioactive spike interferes with some measurement methods involving gross counting of (generally, a spike is preferred to because of its longer (60-day) half-life also, it is absent [Pg.40]

Liquid scintillation counting methods for have been described by Magno et al. (1972) Bogen (1973) Gabay et al (1974) Rhodes (1965) Horrocks (1974) and Ross (1970). The methods require the chemical separation of iodine from the sample material, with the iodine incorporated into a suitable liquid scintillation cocktail for measurement of the beta and conversion electron activity associated with [Pg.40]

The reported detection limits for by liquid scintillation range from 0.4 to 1.2 pCi. [Pg.40]

Beta counting of solid samples of iodine as Agl or other forms has been considered by several investigators but has not been generally applied to environmental analyses (Bogen, 1973 Gabay et al., 1974). Both gas-flow counters and low-level beta-scintillation counters have been considered. The detection limits are about the same as for liquid scintillation counting, but larger uncertainties result from selfabsorption in the sample to be counted. [Pg.40]

Levels of I, 1, and in environmental samples have been determined by using gamma- eind x-ray spectrometry (Eldridge and [Pg.40]

The signal of interest has been calculated above. Now, the noise needs to be estimated. Noise is defined as all the signal sources that are not of interest, but superpose the signal of interest. In our case the thermal noise and related sources, which is system immanent to any circuit is almost negligible even for small sample sizes, as the following calculation will show. The thermal noise of a 10 kfl resistor R at room temperature with a frequency bandwidth A/ of 100 kHz can be calculated to [Pg.54]

Lithium deposited on an anode during a charge is chemically active and reacts with organic electrolytes after deposition. Then, the lithium is consumed during cycling. The cycling efficiency (percent) of a lithium anode (Eff) is basically defined by Eq. (1) [23], where Qp is the amount of electricity needed to plate lithium and 2S is the amount of electricity needed to strip all the plated lithium. As Eff is less than 100 percent, an excess of lithium is included in a practical rechargeable cell to compensate for the consumed lithium. [Pg.342]

The value of Eff is affected by many experimental conditions other than the electrolyte and anode materials. The experimental conditions include such factors as the cell configuration, electrode orientation, electrode surface area, working electrode substrate, charge-discharge currents, charge quantity, and amount of electrolyte. [Pg.342]

When Al, Pt, Ni, or Cu is used as the substrate of lithium plating with 1 mol L 1 LiC104- PC/l, 2 -dimethoxyethane (DME), Eff decreases in the order is Al Pt Ni Cu [26]. Lithium is easily alloyed electrochemically with many metals [27] the Eff values measured in these experiments could include those of lithium alloys. [Pg.342]

Lithium cycling on a lithium substrate (Li-on-Li cycling) is another frequently used Li half-cell test [28], in which an excess of lithium (Qex is plated on a metal working electrode, and then constant-capacity cycling ( 2ps) Qps is smaller than Qex) is continued until all the excess lithium is consumed. The FOM can be evaluated as shown in Eq.(4). [Pg.342]

The figure of merit (FOM) for lithium cycling efficiency [24] also is often used to evaluate the cyclability of a lithium cell. The FOM is defined as the number of cycles completed by one atom of lithium before it becomes electrochemically inactive. Equation (2) is derived from the above definition. [Pg.342]

Capillary viscometers are simple and inexpensive. They are normally constructed from glass and resemble a U-tube with a capillary section between two bulbs. The initial design originated with Ostwald, however the Caimon-Fenske moves the bulbs into the same vertical axis and is more common today. Capillary viscometers are normally immersed in a constant-temperature bath to regulate the sample temperature precisely during the experiment. To determine the viscosity, the fluid in the viscometer is drawn into the upper bulb using a vacuum. The vacuum is released and the time for the fluid to fall past the marks, above and below the [Pg.73]

Ah three methods discussed above appear to provide equaUy high quality ionic liquid viscosity data. However, the rotational viscometer has the potential to provide additional information concerning the Newtonian behavior of the ionic liquids. The caphlary method has been by far the most commonly used to generate the ionic [Pg.74]


The above described MBN measuring method investigates the stress state, so the obtained results are independent from the friction coefficient. [Pg.9]

The second method applies eddy-current probes in a new measurement method. The principle circuit of this method is presented in fig. 2. [Pg.368]

All described sensor probes scan an edge of the same material to get the characteristic step response of each system. The derivation of this curve (see eq.(4) ) causes the impulse responses. The measurement frequency is 100 kHz, the distance between sensor and structure 0. Chapter 4.2.1. and 4.2.2. compare several sensors and measurement methods and show the importance of the impulse response for the comparison. [Pg.369]

Manufacturer verification" describes the measurement method of flaw charaeteristics. These characteristies are reported on the data sheet delivered with the equipment. Measurements are performed on a representative sample of flaw deteetors produeed. [Pg.701]

This automatic velocity measurement method (AUTO-V) has also been suecessfijlly applied to other materials sueh as non-ferrous metals and even eeramics and plasties. The only requirement for this type of sequential velocity and thickness measurement is a certain isotropy of the material materials having anisotropie properties will lead to incorrect thickness readings due to the velocity difference in the two orthogonal directions. [Pg.764]

This paper intends to give, through different examples, guide-lines for characterization of array probes. We discuss, particularly, beam pattern measurement methods and raise the question whether it is useful to achieve a full characterization of all beams steered by the probe or to limit the characterization to a minimum set of acoustic configurations. An automatic bench for full characterization of tube inspection probes is described. [Pg.819]

Fig. 1 Measuring method of echo height of side drill hole Fig. 2 Calculation Method of Echo Directivity [or SH Wave Probes... Fig. 1 Measuring method of echo height of side drill hole Fig. 2 Calculation Method of Echo Directivity [or SH Wave Probes...
Accurate enthalpies of solid-solid transitions and solid-liquid transitions (fiision) are usually detennined in an adiabatic heat capacity calorimeter. Measurements of lower precision can be made with a differential scaiming calorimeter (see later). Enthalpies of vaporization are usually detennined by the measurement of the amount of energy required to vaporize a known mass of sample. The various measurement methods have been critically reviewed by Majer and Svoboda [9]. The actual teclmique used depends on the vapour pressure of the material. Methods based on... [Pg.1910]

From a series of isotope ratio measurements, the precision of measurement can be assessed statistically, as shown here. Precision reveals the reproducibility of the measurement method, but it does not provide information on the accuracy of the measurement (see also Figures 48.8 and 48.9). [Pg.362]

The 2eta potential (Fig. 8) is essentially the potential that can be measured at the surface of shear that forms if the sohd was to be moved relative to the surrounding ionic medium. Techniques for the measurement of the 2eta potentials of particles of various si2es are collectively known as electrokinetic potential measurement methods and include microelectrophoresis, streaming potential, sedimentation potential, and electro osmosis (19). A numerical value for 2eta potential from microelectrophoresis can be obtained to a first approximation from equation 2, where Tf = viscosity of the liquid, e = dielectric constant of the medium within the electrical double layer, = electrophoretic velocity, and E = electric field. [Pg.44]

A number of considerations should be evaluated before a flow measurement method can be selected for any appHcation. These considerations can be divided into four general classifications fluid properties ambient environment measurement requirements and economics. [Pg.55]

Measurement Method Selection. A measurement method should meet sampling strategy requirements to the degree that the data can be used for decision making. This does not mean that it must be the optimum method with respect to all requirements. The range of methods available is limited and it is often necessary to select a method deficient in one or more attributes but which can yield data from which conclusions can be drawn with the desired degree of confidence. Some of the attributes to be considered in selecting a method foUow. [Pg.107]

Intrusiveness. Workers are likely to alter their behavior, consciously or unconsciously, when they are observed. To the extent that a worker s exposure is related to the worker s actions, this change can distort the representativeness of the evaluation. Measurement methods which require the close presence of the person collecting the sample are more likely to influence the result than samples collected with unobtmsive devices worn by the worker. [Pg.108]

Proximity to Breathing Zone. Whereas all exposure measurement methods attempt to sample from air that is likely to be inhaled, some methods do so better than others. A sampler fixed some distance away from a breathing area is not usually accurate in measuring exposure. Even using mobile samplers that move with the worker, the few centimeters in distance from the nose and mouth to the position of the sampler, has been found to make a difference. [Pg.108]

Decision Process. In many cases, the decision regarding the need for exposure reduction measures is obvious and no formal statistical procedure is necessary. However, as exposure criteria are lowered, and control becomes more difficult, close calls become more common, and a logical decision-making process is needed. A typical process is shown in Eigure 2. Even when decision making is easy it is useful to remember the process and the assumptions involved. Based on an evaluation, decisions are made regarding control. The evaluation and decision steps caimot be separated because the conduct of the evaluation, the strategy, measurement method, and data collection are all a part of the decision process. [Pg.108]

Additional complications can occur if the mode of deformation of the material in the process differs from that of the measurement method. Most fluid rheology measurements are made under shear. If the material is extended, broken into droplets, or drawn into filaments, the extensional viscosity may be a more appropriate quantity for correlation with performance. This is the case in the parting nip of a roUer in which filamenting paint can cause roUer spatter if the extensional viscosity exceeds certain limits (109). In a number of cases shear stress is the key factor rather than shear rate, and controlled stress measurements are necessary. [Pg.203]

A wide variety of particle size measurement methods have evolved to meet the almost endless variabiUty of iadustrial needs. For iastance, distinct technologies are requited if in situ analysis is requited, as opposed to sampling and performing the measurement at a later time and/or in a different location. In certain cases, it is necessary to perform the measurement in real time, such as in an on-line appHcation when size information is used for process control (qv), and in other cases, analysis following the completion of the finished product is satisfactory. Some methods rapidly count and measure particles individually other methods measure numerous particles simultaneously. Some methods have been developed or adapted to measure the size distribution of dry or airborne particles, or particles dispersed inhquids. [Pg.130]

Zinc coatings are covered by an ASTM specification (143). Because of the varying purity of 2inc deposits from chloride and 2incate baths, some thickness measuring methods can vary considerably (39). Methods based on physical measurement of magnetic methods (144,145) are used for best accuracy. [Pg.165]

The measured diameters of particles shoiild as nearly as possible represent the effective particle size of a dust as it exists in the gas stream. When significant flocculation exists, it is sometimes possible to use measurement methods based on gravity settling. [Pg.1582]

Methods of Measurement Methods of characterizing the rate process of wetting include four approaches as illustrated in Table 20-37. The first considers the ability of a drop to spread across the powder. This approach involves the measurement of a contact angle of a drop on a powder compact. The contact angle is a measure of the affinity of the fluid for the solid as given by the Young-Dupre equation, or... [Pg.1879]

Of the parameters making up the Hatta number, hquid diffusivity data and measurement methods are weh reviewed in the hterature. [Pg.2109]

Meister, D. 1987. Behavioral Analysis and Measurement Methods. John Wiley Sons, New York. [Pg.152]

Field coating of welds has always presented problems. Straw and jute with a greasy material was employed in 1910, but this later saponified in the soil. By chance the pharmacist Schade of Berlin learned of this problem and recommended the use of petroleum jelly in a bandage-like application. Hot-applied bitumen bands, as used by pipe works since 1928. proved to be most durable. Since 1930, electrical measuring methods have played an important part in research into insulation bands and pipe coverings carried out by the Gas Institute in Karlsruhe, the present-day Engier-Bunte Institute 18). [Pg.7]

The basic standard for cathodic protection was laid down for the first time in DIN 30676 to which all the application areas of the different branches of protection can be referred. In this the most important point is the technique for accurately measuring the object/soil potential [58]. The usual off-potential measurement method for underground installations has been slowly implemented and enforced in Europe since the 1960s [59]. [Pg.19]

All methods of IR-free technique involve finally switching-off and reverse switching techniques. In these are included bridge methods [5, 8, 9], ac methods, and impulse methods [10, 11]. All of these have no practical significance. Finally, measurement methods are also derived from Eq. (3-25) with the help of varying potential gradients on the soil surface, so that x is replaced by ... [Pg.93]

Various electromagnetic and mechanical measuring methods are used to investigate the old well casings to determine whether there is external or internal corrosion. [Pg.418]

Measure of averaging time Cyclic factor measured Measurement method with same averaging time Effect with same averaging time... [Pg.47]

The continuous methods combine sample collection and the measurement technique in one automated process. The measurement methods used for continuous analyzers include conductometric, colorimetric, coulometric, and amperometric techniques for the determination of SO2 collected in a liquid medium (7). Other continuous methods utilize physicochemical techniques for detection of SO2 in a gas stream. These include flame photometric detection (described earlier) and fluorescence spectroscopy (8). Instruments based on all of these principles are available which meet standard performance specifications. [Pg.201]

Electrical mobility is utilized to obtain size distribution information in the 0.01-1.0 /xm diameter range. This measurement method requires unipolar... [Pg.204]

AGMA 390.03, Gear Classification, Materials, and Measuring Methods of Unassembled Gears, Gear Handbook, Vol. 1, Washington, D.C., 1973. [Pg.537]


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