scholarly journals Slow growth of a crack with contact zone

Author(s):  
A.A. Kaminsky ◽  
◽  
M.F. Selivanov ◽  
Keyword(s):  
2021 ◽  
Vol 410 ◽  
pp. 841-846
Author(s):  
Valentina I. Loganina

Information on deformation of coatings at different loading levels during peeling is given. It is shown that the deformations of the organosilicon coating appear already at the initial stages of loading, and the obtained data correlate with the data on acoustic emission. For a polyvinyl acetate coating at low loading levels, equal to 0.3-0.4 R, the release of acoustic signal energy is not observed. The absence of signals with a large amplitude at loading levels up to 0.7-0.8 R indicates the development of plastic deformations in the contact zone of the coating with the substrate. It was found that early localization of bond breaking in the contact zone, leading to the formation of a fracture focus, occurs in organosilicon coatings KO-168. For PVAC coatings, an abrupt growth of cracks is characteristic, which is preceded by its slow growth. The pseudoplastic mechanism of destruction of PVAC coatings has been established. The influence of the nature of the substrate on the change in the nature of the peeling of the coatings is considered.


2006 ◽  
pp. 84-89 ◽  
Author(s):  
N. Birdsall

Reasons of high inequality in the modern world are considered in the article. In developing countries it interacts with underdeveloped markets and inefficient government programs to slow growth, which in turn slows progress in reducing poverty. Increasing reach of global markets makes rising inequality more likely and deepens the gap between rich and poor countries. Because global markets work better for the already rich, we should increase the representation of poor countries in global fora.


1986 ◽  
Vol 14 (4) ◽  
pp. 264-291
Author(s):  
K. L. Oblizajek ◽  
A. G. Veith

Abstract Treadwear is explained by specific mechanical properties and actions of tires. Rubber shear stresses in the contact zone between the tire and the road become large at large slip angles. When normal stresses are insufficient to prevent sliding at the rear of the footprint, wear occurs at a rate that depends on test severity. Two experimental approaches are described to relate treadwear to tire characteristics. The first uses transducers imbedded in a simulated road surface to obtain direct measurements of contact stresses on the loaded, freely-rolling, steered tires. The second approach is developed with the aid of a simple carcass, tread-band, tread-rubber tire model. Various tire structural configurations; characterized by carcass spring rate, edgewise flexural band stiffness, and tread rubber shear stiffness; are simulated and lateral shear stress response in the contact zone is determined. Tires featuring high band stiffness and low carcass stiffness generate lower lateral shear stress levels. Furthermore, coupling of tread-rubber stiffness and band flexural rigidity are important in determining level of shear stresses. Laboratory measurements with the described apparatus produced values of tread-band bending and carcass lateral stiffness for several tire constructions. Good correlation is shown between treadwear and a broad range of tire stiffness and test course severities.


2013 ◽  
Vol 2 (1) ◽  
pp. 28-33
Author(s):  
Piotr Kotula
Keyword(s):  

Abstract In the contact zone of the Bardo Structure and Kłodzko-Złoty Stok Intrusion and Kłodzko Metamorphic, metasomatic orebearing quartz-carbonate veins rich in Sb, Zn, Cu, Ag, Au, Pb are present. In 1771 the mine ,,Reiche Silber Gluck” within stibnite vein was founded in Dębowina near Bardo. Its entrance was discovered again in 2007. The stibnite vein is mainly build of stibnite and sphalerite and of quartz and dolomite rich in Mn. Stibnite crystallizes as columnar or forming radiate centres and aciculars. Its crystals reach size to 2 mm. Sphalerite appears as individual anhedral and polymineralic grained concentrations reaching size to 2,5 mm. Earlier pyrite and arsenopyrite crystallized - they occur locally in this deposit. There were found also in the deposit tetrahedrite rich in Ag, what wasn't reported earlier in studies from the mine in Dębowina.


Alloy Digest ◽  
1979 ◽  
Vol 28 (4) ◽  

Abstract CERROBASE Alloy is a bismuth-lead eutectic alloy that melts at 255 F (124 C). It is characterized by initial shrinkage followed by slow growth. Its low melting temperature and/or growth-shrinkage characteristics make it a useful industrial material. Among many applications, it is used for (1) anchoring inserts in wood, metal or plastics, (2) drop-hammer dies, (3) duplicate patterns in pottery and foundry, and (4) liquid metal bath for heat treating. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on casting, forming, heat treating, and machining. Filing Code: Bi-11. Producer or source: Cerro Metal Products.


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