Graying Test

In a specification for testing graying effects issued by the automotive industry, specimens are exposed to artificial weathering for 800 h in a 1200 CPS Xenotester. The test cycle involves 18 min raining and 102 min irradiation with a radiation intensity of 50 W/m and a black standard temperature of 63°C. Subsequently, the test materials are dipped for five minutes in an aqueous solution of automotive detergent (95 5 vol. ratio). Solution temperature is 85°C [514]. 

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Eor the Gray-King coke-type assay test (91,92) coal is heated in a retort tube to 600°C and the product coke is compared to a series of standard cokes. Eor a strongly swelling coal, enough anthracite or electrode carbon is added to the coal to suppress the swelling. This method is primarily used in Europe. 

Grayness of a fabric swatch is not directly proportional to its content of black pigment (or artificial sod). A basic formula relating reflectance to the pigment content or concentration can be appHed to the evaluation of detergency test swatches (51,99—101). In simple form, an adaptation of the Kubelka-Munk equation, it states that the quantity (1 — i ) /2R (where R is the fraction of light reflected from the sample) is a linear function of the sod content of the sample. 

Gray and Follansbee [44] quasi-statically tested OFE copper samples that had been shock loaded to 10 GPa and pulse durations of 0.1 fis, 1 /rs, and 2 fus. The quasi-static stress-strain curves are shown in Fig. 7.10 with the response of annealed starting copper included for comparison. The yield strength of shock-loaded copper is observed to increase with pulse duration, as the work-hardening rate is seen to systematically decrease. 

Figure 5-30. Expander during hot mechanical running test in Jeannette, Pennsylvania facility. Four inches (102 mm) of insulation is secured to the casing with refractory-type anchors welded to the casing. Final site treatment includes a layer of 1.1 Ib/fF (5 kg/m ) lead foil for acoustic purposes and two outer coats of open-weave glass cloth and emulsion reinforcement, for an aluminum gray color.

With attribute data the product either has or has not the ascribed attribute - it can therefore either pass or fail the test. There are no gray areas. Attributes are measured on a go or no-go basis. With variables, the product can be evaluated on a scale of measurement. However, with inspection by attributes we sometimes use an acceptable quality level (AQL) that allows us to ship a certain percent defective in a large batch of product -... 

Inspection and test status is either reject or accept . There are no gray areas. If not fully conforming the product should be rejected and identified as such. If conforming the product should be accepted and identified as such. If a nonconforming product is later deemed acceptable, the identification should be changed but this can lead to problems. 

Other testing machines and techniques have been described by Gray and Jenny Villemeur, Wright , Barwell and Wright , Field and Waters , and Waterhouse... 

Self-Test 7.1 IB Use the information in Table 7.3 or Appendix 2A to determine which allotrope is the more ordered form and predict the sign of AS for each transition (a) white tin (Fig. 7.14) changes into gray tin at 25°C (b) diamond changes into graphite at 25°C. 

Successive pivoting resonances of a covalent bond allows for electrical conduction to occur, as shown in Figure 1-1. A test of this theory was provided by gray and white tin. Gray tin is not metallic because all its valence orbitals are used for bonding and there is no metallic orbital available. White tin, on the other hand, has the metallic orbital available and therefore has metallic properties. 

FIGURE 9.10 In vitro cytotoxicity testing of individual components of recombinant resilin curing polymer system. The light gray areas represent green fluorescence, evidence of live cells, (a) Ammonium persulphate... 

Figure 4.51. Distribution of experimental data. Six experimental formulations (strengths 1, 2, resp. 3 for formulations A, respectively B) were tested for cumulative release at five sampling times (10, 20, 30, 45, respectively 60 min.). Twelve tablets of each formulation were tested, for a total of 347 measurements (13 data points were lost to equipment malfunction and handling errors). The group means were normalized to 100% and the distribution of all points was calculated (bin width 0.5%, her depicted as a trace). The central portion is well represented by a combination of two Gaussian distributions centered on = 100, one that represents the majority of points, see Fig. 4.52, and another that is essentially due to the 10-minute data for formulation B. The data point marked with an arrow and the asymmetry must be ignored if a reasonable model is to be fit. There is room for some variation of the coefficients, as is demonstrated by the two representative curves (gray coefficients in parentheses, h = peak height, s = SD), that all yield very similar GOF-figures. (See Table 3.4.)...

Gray, L.E. (1998). Tiered screening and testing strategy for xenoestrogens and antiandrogens. Toxicology Letters 103, 677-680. 

On a practical basis, if we wish to set up this system, we would assemble a set of "color-chips". Each color-chip would be specified by two factors, H = hue, and V/C, which is value (grayness) modified by chroma (saturation). The actual number of layers in the Munsell Color Tree was determined by "minimum perceptual difference". That is, the minimum change that produces a visual perceptible difference. This arrangement specifies all light colors as well cis the dark ones. To use such a system, one would choose the color-chip closest to the hue and saturation of the test color and thus obtain values for H and V/C. However, it was soon discovered that the system was not perfect. Reasons for this include the facts that the hues defined by Munsell are not those of the primaries of the human eye. Furthermore, Munsell was somewhat subjective in his definitions of hues. 

Figure 3.19 Schematic representation of surface alloy stability tests. White spheres denote adsorbed hydrogen, black spheres denote solute metal atoms, and gray spheres denote host metal atoms. Adapted from [Greeley and Nprskov, 2007] see this reference for more details.

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