Fault kinematics at the Hengill Triple Junction, SW-Iceland, derived from surface fracture pattern

2020 ◽  
Vol 391 ◽  
pp. 106439 ◽  
Author(s):  
Louis Steigerwald ◽  
Páll Einarsson ◽  
Ásta Rut Hjartardóttir
2013 ◽  
Vol 765-767 ◽  
pp. 3196-3199
Author(s):  
Qing Miao ◽  
Wen Feng Ding ◽  
Jiu Hua Xu ◽  
Biao Zhao ◽  
Jian He

Particulate reinforced titanium matrix composites (PTMCs) are attracting increasingly attention in various engineering applications. In this paper, comparative grinding experiments of PTMCs were carried out using WA abrasive wheel and CBN abrasive wheel. The morphology of the ground surface was observed by scanning electron microscope. The main results are summarized as follows: (1) The damage of reinforcements in the PTMCs results from the plowing and shearing during grinding in the form of crater, micron gap, broken, coating and micron crack. (2) The formation of grinding chip is a function of the collaborate removal of reinforcements and matrix material. (3) The surface fracture pattern of PTMCs using WA wheel is to form the grinding chip through severe extrusion. While using CBN wheel, the abrasion due to the formation of the wear debris is the main surface fracture pattern of PTMCs.


2000 ◽  
Author(s):  
D. Lillington ◽  
H. Cotal ◽  
J. Ermer ◽  
D. Friedman ◽  
T. Moriarty ◽  
...  
Keyword(s):  

2019 ◽  
Vol 85 (12) ◽  
pp. 43-50
Author(s):  
D. A. Movenko ◽  
L. V. Morozova ◽  
S. V. Shurtakov

The results of studying operational destruction of a high-loaded cardan shaft of the propeller engine made of steel 38KhN3MFA are presented to elucidate the cause of damage and develop a set of recommendations and measures aimed at elimination of adverse factors. Methods of scanning electron and optical microscopy, as well as X-ray spectral microanalysis are used to determine the mechanical properties, chemical composition, microstructure, and fracture pattern of cardan shaft fragments. It is shown that the mechanical properties and chemical composition of the material correspond to the requirements of the regulatory documentation, defects of metallurgical origin both in the shaft metal and in the fractures are absent. The microstructure of the studied shaft fragments is tempered martensite. Fractographic analysis revealed that the destruction of cardan shaft occurred by a static mechanism. The fracture surface is coated with corrosion products. The revealed cracks developed by the mechanism of corrosion cracking due to violation of the protective coating on the shaft. The results of the study showed that the destruction of the cardan shaft of a propeller engine made of steel 38Kh3MFA occurred due to formation and development of spiral cracks by the mechanism of stress corrosion cracking under loads below the yield point of steel. The reason for «neck» formation upon destruction of the shaft fragment is attributed to the yield point of steel attained during operation. Regular preventive inspections are recommended to assess the safety of the protective coating on the shaft surface to exclude formation and development of corrosion cracks.


Anales AFA ◽  
2019 ◽  
Vol 30 (3) ◽  
pp. 47-51
Author(s):  
P.I. Achával ◽  
C. L. Di Prinzio

In this paper the migration of a grain triple junction in apure ice sample with bubbles at -5°C was studied for almost 3hs. This allowed tracking the progress of the Grain Boundary (BG) and its interaction with the bubbles. The evolution of the grain triple junction was recorded from successive photographs obtained witha LEICA® optical microscope. Simultaneously, numerical simulations were carried out using Monte Carlo to obtain some physical parameters characteristic of the BG migration on ice.


2017 ◽  
Vol 68 (1) ◽  
pp. 94-100
Author(s):  
Oana Tanculescu ◽  
Adrian Doloca ◽  
Raluca Maria Vieriu ◽  
Florentina Mocanu ◽  
Gabriela Ifteni ◽  
...  

The load-bearing capacity and fracture pattern of direct inlay-retained FRC FDPs with two different cross-sectional designs of the ponticwere tested. The aim of the study was to evaluate a new fibre disposition. Two types of composites, Filtek Bulk Fill Posterior Restorative and Filtek Z250 (3M/ESPE, St. Paul, MN, USA), and one braided polyethylene fibre, Construct (Kerr, USA) were used. The results of the study suggested that the new tested disposition of the fibres prevented in some extend the delamination of the composite on buccal and facial sides of the pontic and increased the load-bearing capacity of the bridges.


2015 ◽  
Vol 8 (1) ◽  
pp. 106-111 ◽  
Author(s):  
Zilong Wang ◽  
Hua Zhang ◽  
Wei Zhao ◽  
Zhigang Zhou ◽  
Mengxun Chen

Research on automatic tracking solar concentrator photovoltaic systems has gained increasing attention in developing the solar PV technology. A paraboloidal concentrator with secondary optic is developed for a three-junction GaInP/GalnAs/Ge solar cell. The concentration ratio of this system is 200 and the photovoltaic cell is cooled by the heat pipe. A detailed analysis on the temperature coefficient influence factors of triple-junction solar cell under different high concentrations (75X, 100X, 125X, 150X, 175X and 200X) has been conducted based on the dish-style concentration photovoltaic system. The results show that under high concentrated light intensity, the temperature coefficient of Voc of triple-junction solar cell is increasing as the concentration ratio increases, from -10.84 mV/°C @ 75X growth to -4.73mV/°C @ 200X. At low concentration, the temperature coefficient of Voc increases rapidly, and then increases slowly as the concentration ratio increases. The temperature dependence of η increased from -0.346%/°C @ 75X growth to - 0.103%/°C @ 200X and the temperature dependence of Pmm and FF increased from -0.125 W/°C, -0.35%/°C @ 75X growth to -0.048W/°C, -0.076%/°C @ 200X respectively. It indicated that the temperature coefficient of three-junction GaInP/GalnAs/Ge solar cell is better than that of crystalline silicon cell array under concentrating light intensity.


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