scholarly journals Role of Impurity Sulphur in the Ductility Trough of Austenitic Iron–Nickel Alloys

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 539 ◽  
Author(s):  
Frédéric Christien
Keyword(s):  
Crack Tip ◽  
Bulk Diffusion ◽  
Tensile Tests ◽  
Ductility Trough ◽  
Iron Nickel ◽  
Iron Nickel Alloys ◽  
Dynamic Embrittlement ◽  
Crack Growth Rates ◽  
Very High

The role of impurity sulphur in the ductility trough of iron–nickel (Fe–Ni) alloys is investigated using hot tensile tests. A strong detrimental effect of some ppm levels of sulphur is demonstrated. In addition, it is shown that, in the ductility trough, material failure occurs through subcritical grain boundary crack propagation, involving dynamic embrittlement at the crack tip, due to the sulphur. Very high intergranular crack growth rates are observed. This is possible because plastic deformation accelerates the transport of sulphur to the crack tip, by several orders of magnitude, compared to normal bulk diffusion. The ductility is recovered at high strain rates, which correlates with a decrease in the sulphur concentration measured on the fracture surface. It is suggested that the main mechanism of sulphur transport is dragging by moving dislocations.

Thermal and Mechanical Couplings in Plain and Wood Fibre Reinforced Polypropylene during Tensile and Fracture Tests

2007 ◽  
Vol 15 (6) ◽  
pp. 453-462 ◽  
Author(s):  
Jean-Christophe Dupre ◽  
Fabienne Lagattu
Keyword(s):  
Thermal Field ◽  
Crack Tip ◽  
Correlation Method ◽  
Infrared Camera ◽  
Tensile Tests ◽  
Image Correlation ◽  
Irreversible Processes ◽  
Heat Sources ◽  
Fracture Tests ◽  
Very High

The aim of this work was to show the influence of spruce fibres on polypropylene, by way of an experimental thermo-mechanical approach. These studies were performed by the simultaneous measurement of the strain field and the thermal field. A digital image correlation method was used for the strain measurements. The thermal field was obtained with the help of an infrared camera. The heat equation established in the context of classical thermodynamics of irreversible processes allowed us to evaluate the heat sources. The main difference between the plain resin and the composite material was that the heat sources dissipated by the composite were locally lower. In tensile tests the plain material allowed the creation of a neck zone with very high strain values. In fracture tests, it also generated very high strains localised at the crack tip. For the composite, the results of tensile tests showed that the presence of wood fibres led to a quasi-brittle failure of the specimen. In fracture tests, a better overstress accommodation was observed near the crack tip by distributing the strains in a wider zone.

THE ROLE OF GRASSLAND IN MANAGEMENT

1968 ◽  
pp. 44-49
Author(s):  
B.K. Cameron
Keyword(s):  
Soil Temperature ◽  
Annual Rainfall ◽  
Silt Loam ◽  
Average Annual Rainfall ◽  
Very High ◽  
Wilting Point

THE PROPERTY to be discussed is a mixed sheep and cropping unit, situated ei ht a miles east of Ashburton and midway between the Ra aia and the Ashburton rivers. Average annual rainfall is 27 in., evenly spread, but there is very high summer evaporation and therefore frequent droughts. On average, the soil is below wilting point for 40 to 50 days each summer. Winters are cold with the soil temperature being below 48°F for about four months each year. The soil is a Lismore stony silt loam averaging 9 in. in depth over gravel.

Role of Vasavaleha in the management of Covid19

2020 ◽  
Vol 11 (SPL1) ◽  
pp. 259-261
Author(s):  
Aamir Khan ◽  
Rajni K. Gurmule
Keyword(s):  
Immune System ◽  
Human Body ◽  
Respiratory Diseases ◽  
Spreading Rate ◽  
Host Immune System ◽  
Shortness Of Breath ◽  
Antitussive Effect ◽  
Corona Viruses ◽  
Very High

Vasavaleha is one of the best medicine given for respiratory diseases. Corona viruses typically affect the respiratory system, causing symptoms such as coughing, fever and shortness of breath. It also affects host immune system of human body. Spreading rate of this disease is very high. Whole world is seeking for the treatment which can uproots this diseases. There in no vaccine available till date against this pandemic disease. Ayurveda mainly focuses on prevention of diseases alongwith its total cure. Rajyakshma Vyadhi is MadhyamMarga Roga as per Ayurveda. It shows many symptoms such as Kasa, Shwasa etc. By overall view of Covid 19, shows its resemblance with Rajyakshma Vyadhi described in Ayurveda. Vasavaleha is a Kalpa which is described in Rogadhikara of Rajyakshma. It shows Kasahara, Shwashara properties. It consists of Vasa, Pipalli, Madhu and Goghrita. These components shows actions like bronchodilation, antitussive effect and many more other actions. Pipalli shows important Rasayana effect. So in present review, we have tried to focus on role of Vasavaleha in the management of Covid 19. This can be used as preventive as well as adjuvant medication in treating Covid 19. There is need of further clinical research to rule of exact action of Vasavaleha against Covid 19.

Highly sinter-active nanocrystalline RE2O3 (RE = Gd, Eu, Dy) by a combustion process, and role of oxidant-to-fuel ratio in preparing their different crystallographic modifications

2007 ◽  
Vol 22 (3) ◽  
pp. 587-594 ◽  
Author(s):  
V. Bedekar ◽  
S.V. Chavan ◽  
A.K. Tyagi
Keyword(s):  
Combustion Process ◽  
Sintering Behavior ◽  
Stoichiometric Ratio ◽  
Monoclinic Modification ◽  
Fuel Ratio ◽  
Metal Nitrates ◽  
Powder Properties ◽  
Very High ◽  
Scanning Electron

Highly sinter-active powders of RE2O3 [rare earth (RE) = Gd, Eu, Dy] have been prepared using the corresponding metal nitrates as the oxidants, and glycine and citric acid as the fuels. Two different oxidant-to-fuel ratios, namely stoichiometric ratio and fuel-deficient ratio were used to explore the possibility of preparing different crystallographic modifications. By a careful control of oxidant-to-fuel ratio, nanocrystalline Eu2O3 and Gd2O3 could be prepared in cubic (C-type) as well as monoclinic (B-type) modifications. However, the high-temperature monoclinic modification could not be obtained for Dy2O3 due to a very high C-to-B-type phase transition temperature. The crystallite size, surface area, and sintering behavior were also studied for powders prepared using different oxidant-to-fuel ratios, and the results showed a remarkable correlation between different fuel contents and powder properties. Some of these powders resulted in pellets of nearly theoretical density. The sintered microstructure was studied by scanning electron microscopy.

DIFFUSION OF Ni63 IN IRON, COBALT, NICKEL, AND TWO IRON–NICKEL ALLOYS

1959 ◽  
Vol 37 (10) ◽  
pp. 1629-1636 ◽  
Author(s):  
J. R. MacEwan ◽  
J. U. MacEwan ◽  
L. Yaffe
Keyword(s):  
Surface Activity ◽  
Nickel Alloys ◽  
Nickel Content ◽  
The Self ◽  
Iron Cobalt ◽  
Self Diffusion ◽  
Cobalt Nickel ◽  
Iron Nickel ◽  
Iron Nickel Alloys ◽  
Cobalt And Nickel

The self-diffusion of nickel and the diffusion of Ni63 into iron, cobalt, and two iron–nickel alloys was studied using the technique of decrease in surface activity, The nickel self-diffusion results are compared to previously reported values. Nickel is found to diffuse more slowly than iron in the iron-rich portion of the iron–nickel system. The rate of nickel diffusion increases with increasing nickel content. A comparison is made between the present results for diffusion of Ni63 into iron, cobalt, and nickel with reported values for diffusion of Co60 and Fe59 in the same metals. In each solvent, the magnitudes of the activation energies, Q, are such that QNi > QCo > QFe.

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