Shape and size of microfine aggregates: X-ray microcomputed tomography vs. laser diffraction

Erdoğan, Sinan Turhan
Fowler, D. W.
Microfine rock aggregates, formed naturally or in a crushing process, pass a #200 ASTM sieve, so have at least two orthogonal principal dimensions less than 75 mu m, the sieve opening size. In this paper, for the first time, we capture true 3-D shape and size data of several different types of microfine aggregates, using X-ray microcomputed tomography (mu CT) with a voxel size of 2 mu m. This information is used to generate shape analyses of various kinds. Particle size distributions are also generated from the mu CT data and quantitatively compared to the results of laser diffraction, which is the leading method for measuring particle size distributions of sub-millimeter size particles. By taking into account the actual particle shape, the differences between mu CT and laser diffraction can be qualitatively explained.


HAMDAN, NM; OZKAN, H; ZIQ, KA; ALBIS, BA (1994-12-01)
Variation of the lattice parameters and thermal expansion coefficients of Bi-2223 superconductor have been measured from room temperature up to the melting point using X-ray diffraction. The lattice parameters (a and c) gradually increase up to about 250 degrees C. Between 250 degrees C to 450 degrees C the variation of the lattice parameters are quite anomalous, in that a remains almost constant while c decreases. From 450 degrees C to 600 degrees C both parameters gradually increase. Above 650 degrees C t...
Microstructural origins of strain heterogeneity in formability of aluminum alloys
Güler, Bara; Efe, Mert; Department of Metallurgical and Materials Engineering (2019)
In forming of sheet metals, strain localizations and subsequent necking are generally induced by geometrical imperfections, such as local thickness variations. Microstructural heterogeneities also take role in strain localizations, yet their influence is neglected when concerning the macro-scale formability. This thesis investigated the effects of microstructural features on the strain localization behavior of aluminum alloys. A small-scale biaxial test device and sample were utilized for this purpose. The ...
Strong coupling constant of a negative parity nucleon with a pi meson in light-cone QCD sum rules
Alıyev, Tahmasıb; Savcı, Mustafa (2017-03-28)
We estimate the strong coupling constant between the negative parity nucleons with pi meson within the lightcone QCD sum rules. A method for eliminating the unwanted contributions coming from the nucleon-nucleon and nucleon-negative parity nucleon transition is presented. It is observed that the value of the strong coupling constant of the negative parity nucleon N* N* pi transition is smaller by about 50% compared to the coupling constant of the positive parity NN pi transition.
Infinite cylinder with a transverse crack and two rigid inclusions under axial tension
Toygar, ME; Gecit, MR (1999-09-15)
This paper considers the problem of an axisymmetric infinite cylinder with a ring shaped crack at z = 0 and two ring-shaped rigid inclusions with negligible thickness at z = +/-L. The cylinder is under the action of uniformly distributed axial tension applied at infinity and its lateral surface is free of traction. It is assumed that the material of the cylinder is linearly elastic and isotropic. Crack surfaces are free and the constant displacements are continuous along the rigid inclusions while the stres...
Shape Optimizations of Metallic Sheets Using a Multigrid Approach
Altinoklu, Askin; Karaova, Gokhan; Ergül, Özgür Salih (2017-09-27)
We present a novel multigrid approach for the shape optimizations of corrugated metallic sheets by using genetic algorithms (GAs) and the multilevel fast multipole algorithm (MLFMA). The overall mechanism is obtained by an efficient integration of GAs and MLFMA, while the optimizations are improved by applying multiple grids at different layers. We show that the multigrid approach provides more effective optimizations than the conventional no-grid optimizations that employ the discretization nodes directly....
Citation Formats
S. T. Erdoğan and D. W. Fowler, “Shape and size of microfine aggregates: X-ray microcomputed tomography vs. laser diffraction,” POWDER TECHNOLOGY, pp. 53–63, 2007, Accessed: 00, 2020. [Online]. Available: