When metallic materials are plastically deformed through a series of roll nips, the end product is quite uniform, due to the malleable properties of the materials. The Papermaking Process: There are several manufacturing processes that shape a continuous web and wind the product on a roll. In the last few decades, the zeitgeist has been to accurately name the test methods in accordance with the function and not to continue using the manufacturer’s earlier assigned name, if it was not technically correct. The Parker Print Surf method is also a roughness tester however, the reporting (in microns roughness) is a function of the cube root of the measured air flow. A rougher surface causes higher airflow therefore these instruments are designated as roughness testers. The two most common instruments that directly report airflow across the surface are the Sheffield and Bendtsen methods. If the Bekk instrument was originally configured to report in Bekk flow, which is the reciprocal of Bekk time, then the test methods would categorize it as a Bekk roughness tester. It is specified here that, in instruments of the abridged spectrophotometer or filter colorimeter type, the UV content of the illumination be adjusted to conform to the CIE illuminant C as defined by a fluorescent reference standard having an assigned value of ISO brightness as described in Annex B. ISO Brightness numbers can exceed 100%, but not by too. Therefore, the ISO standard will always yield a higher brightness versus TAPPI for the same paper. The fluorescence present in a paper sample, which can provide a significant contribution to brightness, will be stimulated more using the ISO standard versus TAPPI. indoor light plus some unfiltered daylight.
Because of its lower UV content, it yields the lowest brightness reading. indoor lighting plus some filtered daylight (tinted windows). ¯ TAPPI - original standard, most common. The Impact of Kappa Number Composition on Eucalyptus Kraft Pulp 63 Brazilian Journal of Chemical Engineering.
Since the reporting for Bekk smoothness is in units of time (seconds), a surface that measures 500 Bekk seconds is smoother than a surface that measures 200 Bekk seconds. An example of this would be the Bekk method, where a smoother surface requires more time for a given volume of air to leak across the surface. In the title of a test method, the term “smoothness” is used when an increasing number is correlates with a smoother surface measurement. Tappi Versus Iso Brightness Standard Average ratng: 5,8/10 3385votesīy: George Hagerty, Technidyne Corporation Terminology: The terms “smoothness” and “roughness” are generally well understood as far as a dictionary meaning goes however, the use of the terms in test methods is sometimes confusing.
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