A statistical index indicating the degree and mechanical effects of grain size heterogeneity in rocks

2021 ◽  
pp. 106292
Author(s):  
Zhenhua Han ◽  
Luqing Zhang ◽  
Rafig Azzam ◽  
Jian Zhou ◽  
Song Wang
Keyword(s):  
Grain Size ◽  
Statistical Index ◽  
Mechanical Effects ◽  
Size Heterogeneity

Unit-bar migration and bar-trough deposition: impacts on hydraulic conductivity and grain size heterogeneity in a sandy streambed

2017 ◽  
Vol 26 (2) ◽  
pp. 553-564 ◽  
Author(s):  
Jesse T. Korus ◽  
Troy E. Gilmore ◽  
Michele M. Waszgis ◽  
Aaron R. Mittelstet
Keyword(s):  
Grain Size ◽  
Hydraulic Conductivity ◽  
Size Heterogeneity

scholarly journals Prosthetic Fracture of a Cemented Exeter Femoral Stem (Case Report)

2016 ◽  
Vol 6 (4) ◽  
Author(s):  
Michael Facek ◽  
Yasser Khatib ◽  
Eric Swarts
Keyword(s):  
Grain Size ◽  
Case Report ◽  
Single Case ◽  
Femoral Stem ◽  
Mechanical Stresses ◽  
Femoral Prosthesis ◽  
Materials Analysis ◽  
Standing Height ◽  
Size Heterogeneity ◽  
Post Implantation

We present a single case of fracture of an Exeter femoral prosthesis at the neck, occurring after a fall from standing height, in a lean 70yr lady at 6 years post implantation. The fracture propagated from the insertion dimple on the superior aspect of the prosthesis shoulder. Materials analysis suggested variance in composition of the alloy, particularly with grain size heterogeneity. Whilst Exeter femoral prosthesis fracture is extremely rare, when it does occur the literature suggests it is often in the context of excessive mechanical stresses (obesity, high offset, falls). However, this case may represent a failure of materials rather than mechanical stresses alone. 

scholarly journals On novel Copper Based Alloys Development via Friction Stir Alloying

2021 ◽  
Author(s):  
Khaja Moiduddin ◽  
Arshad Noor Siddiquee ◽  
Mustufa Haider Abidi ◽  
Syed Hammad Mian ◽  
Muneer Khan Mohammed
Keyword(s):  
Grain Size ◽  
Base Metals ◽  
Micro Hardness ◽  
Alloy Structure ◽  
Structural Morphology ◽  
X Ray ◽  
Friction Stir ◽  
Commercially Pure ◽  
Size Heterogeneity ◽  
Pure Cu

Friction stir alloying (FSA) of commercially pure Cu with Ni, Zn, and Mg is implemented in the current study. The successfully fabricated alloy structure has been scrutinized in terms of mechanical and micro-structural standpoints. Energy-dispersive X-ray spectroscopy revealed a uniform distribution of alloying elements and coalescence at the atomic level. The compositional and grain size heterogeneity is managed in the stir zone, which pave way for microstructural control using FSA. Thus, the present study carries significance for the development of novel materials whose fabrication requires temperature far below the melting point of base metals. Ultra-refinement of grains is found to accompany the alloying process, with ~ 440 nm being the smallest grain size. Maximum and average micro-hardness enhancement of 18.4 % and 6 % is observed for the fabricated alloy. Tensile properties have also been investigated and co-related with the micro-structural morphology. The shift towards grain bimodality has also been reported, which is a highly sought property in the present day, especially to overcome the strength-ductility trade-off.

scholarly journals On Novel Copper Based Alloys Development via Friction Stir Alloying

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 498
Author(s):  
Khaja Moiduddin ◽  
Arshad Noor Siddiquee ◽  
Mustufa Haider Abidi ◽  
Syed Hammad Mian ◽  
Muneer Khan Mohammed
Keyword(s):  
Grain Size ◽  
Base Metals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Friction Stir ◽  
Commercially Pure ◽  
Microstructural Morphology ◽  
Fcc Phase ◽  
Size Heterogeneity ◽  
Pure Cu

Friction stir alloying (FSA) of commercially pure Cu with Ni, Zn, and Mg is implemented in the current study. Mechanical and microstructural aspects of the successfully fabricated alloy structure have been examined. Energy dispersive X-ray spectroscopy revealed a uniform distribution of alloying elements and coalescence at the atomic level. The compositional and grain size heterogeneity is managed in the stir zone, allowing for microstructural control with FSA. Thus, the present study is essential for the development of novel materials whose fabrication requires temperature well below the melting point of base metals. The alloying process is found to be accompanied by ultra-refined grains, with the smallest grain size being ~0.44 μm. The fabricated alloy managed to retain the FCC phase, and no brittle intermetallic compounds formed, according to X-ray diffraction. The fabricated alloy exhibits maximum and average microhardness enhancements of 18.4% and 6%, respectively. Tensile properties have also been investigated and correlated with microstructural morphology. A shift toward grain bimodality has also been documented, which is a highly sought-after property nowadays, especially to overcome the strength-ductility trade-off.

scholarly journals Life-cycle analysis of coesite-bearing garnet

2021 ◽  
pp. 1-20
Author(s):  
Jan Schönig ◽  
Hilmar von Eynatten ◽  
Guido Meinhold ◽  
N. Keno Lünsdorf
Keyword(s):  
Grain Size ◽  
Fine Fraction ◽  
Fine Sand ◽  
Inclusion Size ◽  
Coarse Sand ◽  
Coarse Fraction ◽  
Surface Erosion ◽  
Fluid Infiltration ◽  
Size Heterogeneity ◽  
High Degree

Abstract Detrital coesite-bearing garnet is the final product of a complex geological cycle including coesite entrapment at ultra-high-pressure conditions, exhumation to Earth’s surface, erosion and sedimentary transport. In contrast to the usual enrichment of high-grade metamorphic garnet in medium- to coarse-sand fractions, coesite-bearing grains are often enriched in the very-fine-sand fraction. To understand this imbalance, we analyse the role of source-rock lithology, inclusion size, inclusion frequency and fluid infiltration on the grain-size heterogeneity of coesite-bearing garnet based on a dataset of 2100 inclusion-bearing grains, of which 93 contain coesite, from the Saxonian Erzgebirge, Germany. By combining inclusion assemblages and garnet chemistry, we show that (1) mafic garnet contains a low number of coesite inclusions per grain and is enriched in the coarse fraction, and (2) felsic garnet contains variable amounts of coesite inclusions per grain, whereby coesite-poor grains are enriched in the coarse fraction and coesite-rich grains extensively disintegrated into smaller fragments resulting in an enrichment in the fine fraction. Raman images reveal that: small coesite inclusions of dimension < 9 µm are primarily monomineralic, whereas larger inclusions partially transformed to quartz; and garnet fracturing, fluid infiltration and the coesite-to-quartz transformation is a late process during exhumation taking place at c. 330°C. A model for the disintegration of coesite-bearing garnet enables the heterogeneous grain-size distribution to be explained by inclusion frequency. High abundances of coesite inclusions cause a high degree of fracturing and fracture connections to smaller inclusions, allowing fluid infiltration and the transformation to quartz, which in turn further promotes garnet disintegration.

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