Knoop hardness test

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Knoop hard·ness num·ber (KHN),

(nūp),
a number obtained by dividing the load in kg applied to a pyramidal diamond of specific size divided by the projected area of the impression: KHN = L/A, where A= the projected area of the impression in mm2 and L = the load in kg; used for measurements of hardness of any materials, especially very hard and brittle substances such as tooth dentin and enamel.

Knoop hardness test

[no̅o̅p]
Etymology: Frederick Knoop, 20th century American metallurgist
a method of assessing surface hardness by measuring resistance to the penetration of an indenting tool made of diamond. The test is commonly used for testing the hardness of teeth.

Knoop hardness test

(noop),

KHT

A test of surface hardness, using a stylus with a pyramidal diamond indenter. The long diagonal of the resulting indentation determines the hardness of the substance.

Knoop hard·ness test

(knūp hahrdnĕs test)
Dental measurement to determine hardness of brittle materials; uses a diamond or rhombic indenting tool; test result provides dental clinicians with the Knoop hardness number.
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The null hypotheses to be tested were that there would be no difference in the degree of conversion and Knoop hardness between the light- and dual-cured cements, regardless of the thickness and type of ceramic during photo-activation, and that there would be no correlation between the values of degree of conversion of the dual-cured resin cement when using two protocols to obtain the initial spectra of uncured materials.
Influence of the interposition of ceramic spacers on the degree of conversion and the hardness of resin cements
The data were expressed in Knoop hardness number (kg/ [mm.
Cross-sectional microhardness of bovine enamel subjected to three paediatric liquid oral medicines: an in vitro study
In 2011, ASTM developed a new E384 standard for Vickers hardness testing that combined several testing procedures, including the E92 standard and the formerly separate Knoop hardness test standards.
Simpler, easier indenting: with a new series of materials testers, instrumented indentation breaks free from the confines of visual measurement
The articles mainly focus on the Vickers hardness measurement but most of the issues discussed are applicable for Knoop hardness measurement as well.
Knoop hardness measurement using computer vision
Paul Darley said the seal, which has a Knoop hardness of 2800, dissipates heat and has better corrosion resistance than other seal materials and thus is a major barrier against leakage.
Combined pump, gen-set attracts interest: developed for firefighting, Darley P2 looking at wider applications; 1000 watts plus 120 to 290 gpm
4:1, at least 30% weight of the filler film hardener comprising large ceramic particles having an average particle size of at least 14 micrometers and a Knoop hardness of at least 1200.
Abrasion resistant coatings from DuPont: Patent No. U.S. 6,592,977 B2
070 mm/s Knoop and Vickers ASTM C 1326 Knoop Hardness of " Advanced Ceramics ASTM C 1327 Vickers Hardness of " Advanced Ceramics JIS R 1610 Vickers Hardness The indenter shall contact of Fine Ceramics the specimen gradually so that the inertia effect is small.
Effect of loading rate upon conventional ceramic microindentation hardness
Now consider that this cutting tool possesses Knoop hardness of 3400, lasts five or six times longer than contemporary tungsten carbide inserts, yet costs only two to three times as much.
Process makes TiB2 a cutting contender
Relative curing degree of polyacid-modified and conventional resin composites determined by surface Knoop hardness.
CURING DEPTH OF BULK- FILL COMPOSITES- AN IN- VITRO STUDY
All materials presented a Knoop hardness decrease after ethanol soaking.
Do new matrix formulations improve resin composite resistance to degradation processes?
Effect of Insertion Method on Knoop Hardness of High Viscous Glass Ionomer Cements.
Comparative evaluation of the remineralising effects and surface microhardness of glass ionomer cement containing grape seed extract and casein phosphopeptide--amorphous calcium phosphate: an in vitro study
The Mohr or the Knoop hardness scales have been used to compare the hardness of various materials for both materials of construction of the mixer, as well as for the fillers that are being mixed.
Internal wear of the batch mixer--part 2

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