Surface marring

Abrasion resistance usually takes the form of a scratch test, in which the material is subjected to many scratches, usually from contact with an abrasive wheel or a stream of falling abrasive material. The degree of abrasion can be determined by loss of weight for severe damage, but is usually measured by evidence of surface marring. 

Thimsen, C.A., and Keil, R.G. (1998) Potential interactions between sedimentary dissolved organic matter and mineral surfaces. Mar. Chem. 62, 65-76. 

Characterizing Physical Properties of Coating Surfaces - Mar Resistance and Surface Structure... 

Trifunctional (meth)acrylate fluorine-containing cyclic and acyclic silane compounds have been prepared that form photocurable resin compositions. Coatings from these resins are anti-fouling and resist organic stains from oil mist and fingerprints without detracting from surface mar resistance. 

Tb.Pf.Ar., total cross-sectional area B.Ar., cortical area Vd.Ar., marrow area LS/BS, total fractional labeled trabecular surface MAR, mineral apposition rate BFR/BS, tissue level bone formation rate. 

Abrasion and Mar Resistance. Abrasion is the wearing away of a surface marring is a disturbance of a surface that alters its appearance (see Weak). A study of the mechanical properties of a series of floor coatings with known wear life concluded that work-to-break values best represented the relative wear lives... 

Scanning electron microscopy observations revealed the lack of surface marring in controls (Figure 1) and the presence of the microorganisms on the surface of experimentals (Figure 2). Despite some growth of the microorganisms on the MIMOS samples, no alterations of the surface were apparent in any of the four sets of experimentals. 

Most solid surfaces are marred by small cracks, and it appears clear that it is often because of the presence of such surface imperfections that observed tensile strengths fall below the theoretical ones. For sodium chloride, the theoretical tensile strength is about 200 kg/mm [136], while that calculated from the work of cohesion would be 40 kg/mm [137], and actual breaking stresses are a hundreth or a thousandth of this, depending on the surface condition and crystal size. Coating the salt crystals with a saturated solution, causing surface deposition of small crystals to occur, resulted in a much lower tensile strength but not if the solution contained some urea. 

Modem furniture pohshes are designed for a wide variety of surfaces, eg, plastics, metals, and synthetic and natural resin coatings. Furniture pohshes impart shine and provide protection from abrasion, marring, and spills. The formulations clean weU in many cases. In common with most other pohshes, furniture pohshes are characterized by ease and speed of apphcation and of buffing, and by either the absence of objectionable odors or the addition of pleasing ones. 

B Shen, DR Jollie, CD Stout, TC Diller, EA Armstrong, CM Gorst, GN La Mar, PJ Stephens, BK Burgess. Azotobacter vmelandii ferredoxm I Alteration of individual surface charges and the [4Ee-4S] cluster reduction potential. 1 Biol Chem 269 8564-8575, 1994. 

A method for quantification of the CL, the so-called MAS corrections, in analogy with the ZAP correction method for X rays (see the article on EPMA), has been proposed to account for the effects of the excess carrier concentration, absorption and surface recombination. In addition, a total internal reflection correction should also be included in the analysis, which leads to the MARS set of corrections. This method can be used for further quantification efforts that also should involve Monte Carlo calculations of the generation of excess carriers. 

Surfaces of plastics may be provided with designs that can give a good grip or that can simulate wood, leather, etc. These types of surfaces should be specified in a manner that will not create undercuts to the withdrawal action from a mold. The undercut effect can be responsible for stresses and marring. A similar condition applies to lettering, and the location of such lettering should conform to smooth withdrawal requirements. 

Although hardness is a somewhat nebulous term, it can be defined in terms of the tensile modulus of elasticity. From a more practical side, it is usually characterized by a combination of three measurable parameters (1) scratch resistance (2) abrasion or mar resistance and (3) indentation under load. To measure scratch resistance or hardness, an approach is where a specimen is moved laterally under a loaded diamond point. The hardness value is expressed as the load divided by the width of the scratch. In other tests, especially in the paint industry, the surface is scratched with lead pencils of different hardnesses. The hardness of the surface is defined by the pencil hardness that first causes a visible scratch. Other tests include a sand-blast spray evaluation. 

The ordinary balance, on the other hand, with suitable adjustment of its parts, gives a measure of the mass of a body, in terms of an arbitrarily selected standard, which depends only on the particular body the same measure would be found if the balance were transported to any part of the earth s surface, or even to another planet, such as Mars or Jupiter. Such a measure may be called absolute. ... 

For the above polyol blend viscosity (Brookfield, ASTM D-2196) = 1500 mPa-S at 23° C. For the reaction mixture working (pot) life 20 min Gardner circular dry times [72°F, 54% relative humidity (RH)] surface dry = 1.0 h, hard dry = 2.0 h, mar free = 3.5 h. For the finished coating gloss (ASTM D-523) = 90+ at 60° impact (ASTM D-2794) = 60 in.-lb direct, 10 in.-lb reverse Tabor abrasion (ASTMD-4060,1000 g load, 1000cycles, CS-17 wheel) = 95.6 mg pendulum hardness = 180 s MEK double rubs (ASTM D4752-95, 50 double rubs) = softened. 

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