Effective indenter radius and frame compliance in instrumented indentation testing using a spherical indenter

We introduce a novel method to correct for imperfect indenter geometry and frame compliance in instrumented indentation testing with a spherical indenter. Effective radii were measured directly from residual indentation marks at various contact depths (ratio of contact depth to indenter radius between 0.1 and 0.9) and were determined as a function of contact depth. Frame compliance was found to depend on contact depth especially at small indentation depths, which is successfully explained using the concept of an extended frame boundary. Improved representative stress-strain values as well as hardness and elastic modulus were obtained over the entire contact depth

Hodge ideals and spectrum of isolated hypersurface singularities

We introduce Hodge ideal spectrum for isolated hypersurface singularities to see the difference between the Hodge ideals and the microlocal $V$-filtration modulo the Jacobian ideal. Via the Tjurina subspectrum, we can compare the Hodge ideal spectrum with the Steenbrink spectrum which can be defined by the microlocal $V$-filtration. As a consequence of a formula of Mustata and Popa, these two spectra coincide in the weighted homogeneous case. We prove sufficient conditions for their coincidence and non-coincidence in some non-weighted-homogeneous cases where the defining function is semi-weighted-homogeneous or with non-degenerate Newton boundary in most cases. We also show that the convenience condition can be avoided in a formula of Zhang for the non-degenerate case, and present an example where the Hodge ideals are not weakly decreasing even modulo the Jacobian ideal.Comment: 29 page

Efficient Experimental Design for Measuring Magnetic Susceptibility of Arbitrarily Shaped Materials by MRI

This work was funded by the Institute for Basic Science, under grant IBS-R015-D1. The SQUID measurement was provided by Dr. Seung-young Park from Korea Basic Science Institute (KBSI). The authors acknowledge the support from the KSMRM MR Engineering Research Group. Copyright © 2018 Korean Society of Magnetic Resonance in Medicine (KSMRM22Nkc

Conventional Vickers and true instrumented indentation hardness determined by instrumented indentation tests

We evaluate Vickers hardness and true instrumented indentation test (IIT) hardness of 24 metals over a wide range of mechanical properties using just IIT parameters by taking into account the real contact morphology beneath the Vickers indenter. Correlating the conventional Vickers hardness, indentation contact morphology, and IIT parameters for the 24 metals reveals relationships between contact depths and apparent material properties. We report the conventional Vickers and true IIT hardnesses measured only from IIT contact depths; these agree well with directly measured hardnesses within ±6% for Vickers hardness and ±10% for true IIT hardness

Spectrum of non-degenerate functions with simplicial Newton polyhedra

We prove a simple formula for the spectrum of non-degenerate functions of 3 variables with simplicial convenient Newton polyhedra (which does not hold in the non-simplicial case) generalizing a picture of Arnold in the 2 variable case. Combining this with Steenbrink's conjecture on a refinement of Yomdin's formula (proved long ago), we can deduce a formula for the spectrum of certain non-isolated surface singularities with simplicial non-degenerate Newton boundaries.Comment: 17 page

Nanomechanical behavior of biodegradable metallic glass for transient electrodes

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Paper on a disc: balancing the capillary-driven flow with a centrifugal force

This paper describes the active control of the capillary-driven flow in paper using a centrifugal device.close191