White reference surface

Unlike the other tests in this section the grade colour is not a performance test but is a test of the whiteness of flour. The Kent-Jones and Martin colour grade is measured by comparing the reflecting power of a dispersion of flour in water with a standard reference surface. A few patent flours give a negative colour grade, which merely indicates that they are whiter than the reference. 

Add 2 drops of color reagent. Compare color produced with reference compounds on spot plate or other white porcelain surface. 

NIR spectra are acquired using dried tissue, either whole or ground. The reflectance is measured relative to a so-called white reference, which is a highly reflective surface, such as Gore-Tex or white ceramic. Near-infrared reflectance spectra, or absorbance spectra, defined as log(l/R), with R being the reflectance, look rather flat. For analysis purposes the second derivative of the spectra is often used, because it enhances certain spectral features. 

The BET surface area and pore volume and diameter of the catalysts were obtained by nitrogen adsorption at -196°C after heat pretreatment under vacuum for 4h at 350°C. The XRD patterns were collected with a Bruker D5005 diffractometer (50 kV, 35 mA) between 3 and 80° 20 using CuKa radiation. The UV-Vis DR spectra were recorded at ambient conditions with a Perkin-Elmer Lambda 19 spectrophotometer equipped with an integrating sphere reflectance accessory. The measurements were carried out at wavelengths ranging from 200 to 2000 nm, using MgO as a standard white reference. 

Experimental. Characterizations of a heterogeneous surface by means of surface group titration utilizing visible and ultraviolet chemical indicators to define the titration end point have frequently been employed with white solid catalysts(7-12), (17-20). Aspects of the surface acid group distribution have often correlated with the catalytic activity of the solid(2-9), (21-25). An adaptation of the technique appears to be suitable for studying the interactions between the surface acid groups in mixtures of carbon black and white reference solids. 

Advantages and disadvantages of the titration technique are discussed in detail elsewhere(26) It suffices here to state that the surface acid group distributions on the white reference solids are sufficiently well defined by the experiment to provide a gauge by which to measure the interaction of carbon black with the white solids in binary mixtures. 

The titration experiments, the EM measurements, and the

complementary information about the properties of the carbon black as manifested in their interactions with the white reference solids. It is appropriate to ask what these results taken together say about the surface properties of carbon black. 

The phase measurement interference microscopy (PMIM) is mainly used for surface analysis. A resolution depth of 0.6 nm can be achieved, whereas the lateral resolution is only in the range of about 1 ftm [White et al., 1990]. A laser beam in the microscope is reflected from the sample surface and simultaneously from a semitransparent smooth reference surface [Stamm, 1992]. The interference pattern is recorded which can be converted into a contour map of the sample surface, e.g., to determine the root-mean-square roughness of materials. 

There are various methods of assessing the state of fusion of PVC. Intact particle boundaries, coated with stabilisers, etc. are very weak. Consequently, immersing the PVC in a liquid such as methylene dichloride causes the particles to separate, giving rise to a white powdery surface (Fig. 6.20). The wall of the pipe has been chamfered to expose the different layers. Fusion is only complete at the inner and outer surfaces, that experienced the highest levels of shear in passing through the extrusion die. A pipe with this level of fusion would have inferior mechanical properties. The fusion of PVC particles is referred to as gelation. As PVC is mixed in an internal mixer, viscous dissipation causes a steady rise in temperature. Samples are removed at various... 

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.

The gray matter, which contains the cell bodies of neurons, is on the outer surface of the cerebrum and forms the cerebral cortex. The white matter, composed of the myelinated axons of neurons, is found underlying the cortex in the core of the cerebrum. These axons are bundled together according to function and organized into units referred to as tracts. The three types of tracts in the cerebrum are ... 

Figure 15 Light microscopy image and Raman spectra of an inclusion in PP film. Top, white light micrograph of the inclusion in the PP film. Bottom, Raman spectra, taken at the surface of the PP film (PP) and 12 pm underneath the film surface (inclusion). The spectrum of the inclusion is compared with the reference spectrum of an additive (taken from a supplied reference sample).

Figure 11 shows the ATR-FTIR spectrum acquired from the surface of the white-colored paint sample after the paint had been dried. Figure 12 shows the closest spectral library database matches obtained Figure 13 compares the spectrum of the surface of the white-colored paint sample with that of a reference library spectrum of a vinyl toluene-modified alkyd. The binder from the dried... 

The G-CSF receptor has been well characterized. It is a single transmembrane polypeptide found on the surface of neutrophils, as well as in various haemopoietic precursor cells, platelets, endothelial cells and, notably, various myeloid leukaemias. (Myeloid means derived from bone marrow leukaemia refers to a cancerous condition in which there is uncontrolled overproduction of white blood cells in the bone marrow or other blood-forming organs. The white cells produced are generally immature/abnormal and result in the suppression of production of healthy white blood cells.)... 

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