Metallographic inspection of the metal-enamel contact zone

1983 ◽  
Vol 25 (6) ◽  
pp. 472-475 ◽  
Author(s):  
Yu. A. Dudnik
Keyword(s):  
Contact Zone ◽  
Metallographic Inspection

Tire Treadwear — A Comprehensive Evaluation of the Factors: Generic Type, Aspect Ratio, Tread Pattern, and Tread Composition Part IV: Laboratory Measurement of Mechanical Properties and Mechanical Actions of Tires Relating to Treadwear

1986 ◽  
Vol 14 (4) ◽  
pp. 264-291
Author(s):  
K. L. Oblizajek ◽  
A. G. Veith
Keyword(s):  
Mechanical Properties ◽  
Shear Stress ◽  
Contact Zone ◽  
Flexural Rigidity ◽  
Comprehensive Evaluation ◽  
Shear Stiffness ◽  
Shear Stresses ◽  
Lateral Shear ◽  
Band Bending ◽  
Tread Rubber

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.

Stibnite vein from Dębowina near Bardo (polish Sudetes)

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

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.

Diachronic trends in the evolution of civilizations in the Nile valley

2018 ◽  
pp. 37-49
Author(s):  
Элеонора Кормышева ◽  
Eleonora Kormysheva
Keyword(s):  
Material Culture ◽  
Social History ◽  
Contact Zone ◽  
Scientific Discourse ◽  
Cultural Development ◽  
Nile Valley ◽  
Mediterranean World ◽  
The Mediterranean

The diachronic trends in socio-economic and cultural development of the societies in the Nile valley are revealed based on the materials from Giza necropolis (the 3rd millennium BC) and the settlement of Abu Erteila (1st century AD). The research made it possible to trace the typological similarities in the evolution of the studied societies in cultural and historical contexts. The main fields of the research were epigraphy, iconography, social history, and material culture. Many previously unknown monuments discovered by Russian archaeologists in Egypt and Sudan were introduced into scientific discourse. The basis was created for studying the Nile valley as a contact zone between the Mediterranean world and Africa.

Contact zone of two different chloroplast lineages and genetic guidelines for seed transfer in Quercus serrata and Quercus crispula

2020 ◽  
Author(s):  
Kataru Onosato ◽  
Takuto Shitara ◽  
Asako Matsumoto ◽  
Ayumi Matsuo ◽  
Yoshihisa Suyama ◽  
...  
Keyword(s):  
Contact Zone ◽  
Quercus Serrata ◽  
Quercus Crispula ◽  
Seed Transfer

Researches Concerning the Phenomena at the Interface for the Sintered Compacts of Titan-Hydroxyapatite

2013 ◽  
Vol 856 ◽  
pp. 164-168 ◽  
Author(s):  
Diana Irinel Băilă
Keyword(s):  
Specific Surface ◽  
Bone Tissue ◽  
Contact Zone ◽  
Cellular Differentiation ◽  
Selective Laser Sintering ◽  
Important Process ◽  
Sintering Process ◽  
Cellular Processes ◽  
Hydroxyapatite Powder ◽  
Ti Powder

The behaviour of metallic powders is very important for manufacturing parts and for realize the prototypes. Manufacturing of the orthopaedic implants by selective laser sintering process can be used in medicine. The powders necessary for SLS process are biomaterials who must assure a good osteointegration of endobone implants like the Ti powder (Ti-6Al-4V) and the hydroxyapatite powder. The conditioned powders is a very important process and is necessary in SLS to obtain medical prothesis and influence the final properties of prothesis. Materials must present a gradient for porosity and one for composition (presents of a bioactive phase in titan matrix). The exterior porosity, in the contact zones with the bone tissue, favors the incipient cellular processes (the adhesion and attachment of osteoblastes, proliferation and cellular differentiation and nucleation of mineral bone). The pores must be open and with a specific surface more great. Its preferred the exterior intercommunicating porosity. The presence of phosphates of calcium in the contact zone of the implant with bone favors the mineral kernel on bone. The report Ca/P of phosphates mineral bone has an ascending evolution towards 10/6 according to hydroxyapatite.

scholarly journals Landscape resistance constrains hybridization across contact zones in a reproductively and morphologically polymorphic salamander

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guillermo Velo-Antón ◽  
André Lourenço ◽  
Pedro Galán ◽  
Alfredo Nicieza ◽  
Pedro Tarroso
Keyword(s):  
Contact Zone ◽  
Environmental Heterogeneity ◽  
Evolutionary Dynamics ◽  
Morphological Differentiation ◽  
Phenotypic Traits ◽  
Hybrid Zones ◽  
Landscape Resistance ◽  
Phenotypic Differentiation ◽  
Contact Zones

AbstractExplicitly accounting for phenotypic differentiation together with environmental heterogeneity is crucial to understand the evolutionary dynamics in hybrid zones. Species showing intra-specific variation in phenotypic traits that meet across environmentally heterogeneous regions constitute excellent natural settings to study the role of phenotypic differentiation and environmental factors in shaping the spatial extent and patterns of admixture in hybrid zones. We studied three environmentally distinct contact zones where morphologically and reproductively divergent subspecies of Salamandra salamandra co-occur: the pueriparous S. s. bernardezi that is mostly parapatric to its three larviparous subspecies neighbours. We used a landscape genetics framework to: (i) characterise the spatial location and extent of each contact zone; (ii) assess patterns of introgression and hybridization between subspecies pairs; and (iii) examine the role of environmental heterogeneity in the evolutionary dynamics of hybrid zones. We found high levels of introgression between parity modes, and between distinct phenotypes, thus demonstrating the evolution to pueriparity alone or morphological differentiation do not lead to reproductive isolation between these highly divergent S. salamandra morphotypes. However, we detected substantial variation in patterns of hybridization across contact zones, being lower in the contact zone located on a topographically complex area. We highlight the importance of accounting for spatial environmental heterogeneity when studying evolutionary dynamics of hybrid zones.

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