Frictional and frictionless granular materials in a split-bottom ring shear cell geometry show wide shear bands under slow, quasi-static deformation. Here, the differences between frictional and frictionless materials are elaborated using discrete element simulations (DEM). Several continuum fields like the density, the velocity field, the deformation gradient and the stress are used here for c...

We report the results of constant strain rate experiments on electroplated, single crystalline copper pillars with diameters between 75 and 525 nm. At slow strain rates, 10 3 s , pillar diameters with 150 nm and above show a size-dependent strength similar to previous reports. Below 150 nm, we find that the size effect vanishes as the strength transitions to a relatively size-independent regime...

We study the population dynamics of lytic viruses which replicate slowly in dividing host cells within an organism or cell culture, and find a range of viral replication rates that allows viruses to persist, avoiding extinction of host cells or dilution of viruses at too rapid or too slow viral replication. For the within-host competition between viral strains with different replication rates, ...

This paper is part of an ongoing effort to develop a test methodology to examine the durability of surface mount interconnects under impact loading conditions. Literature indicates that as the drop height is increased, there is a transition in the failure site from the ductile solder to the brittle intermetallic or the copper traces. Not much work has been done to understand this phenomenon. Th...

The phenomenon of surrounding rock damage and rupture caused by high temperatures is widespread, has become a potential threat to the safety nuclear waste disposal repositories. In order reveal energy distribution pattern fractured granite during failure process under different confining pressures, triaxial compression tests were carried out on rocks with initial thermal damage. Firstly, was tr...

Slow embryonic heart rates at gestational age 7 weeks or less are associated with high risk of first trimester death. Our goal was to determine the prognosis for those embryos with slow early heart rates who survive the first trimester. We prospectively recorded embryonic heart rates for all obstetrical sonograms obtained on singleton pregnancies at or before 7.0 weeks' gestation since 1993. We...

The Sherwood-Frost constitutive model is widely used to predict the mechanical behavior of polymer materials, and it a very important material model. In this study, stress-strain curve high-density polyethylene (HDPE) with strain rate ranging from 935 5450 s−1 was obtained through split Hopkinson bar test device. Based on HDPE dynamic performance test, method for determining strain-rate paramet...

BACKGROUND Systolic left ventricular function during therapeutic hypothermia is found both to improve and to decline. We hypothesized that this discrepancy would depend on the heart rate and the variables used to assess systolic function. METHODS In 16 pigs, cardiac performance was assessed by measurements of invasive pressures and thermodilution cardiac output and with 2D strain echocardiogr...

We traced the Chlamydia trachomatis L2b variant in Amsterdam and San Francisco. All recent lymphogranuloma venereum cases in Amsterdam were caused by the L2b variant. This variant was also present in the 1980s in San Francisco. Thus, the current "outbreak" is most likely a slowly evolving epidemic.