Using numerical MHD simulations, we have studied the evolution of the magnetorotational instability in stratified accretion disks in which the ionization fraction (and therefore resistivity) varies substantially with height. This model is appropriate to dense, cold disks around protostars or dwarf nova systems which are ionized by external irradiation of cosmic rays or high-energy photons. We f...

We obtain global solutions of radiatively inefficiently accretion flows around black holes. Whether and where convection develops in a flow are self-consistently determined with the mixing-length theory. The solutions can be divided into three types according to the strength of normal viscosity. Type I solution corresponds to large viscosity parameter α>∼ 0.1, which is purely advectiondominated...

6 Fluid parcels can exchange water properties when coming in contact with each other, leading to 7 mixing. The trajectory encounter number, which quantifies the number of fluid parcel trajectories 8 that pass close to a reference trajectory over a finite time interval, is introduced as a measure of 9 the mixing potential of a flow. Regions characterized by low encounter numbers, such as cores 1...

The impacts of climate change on tropospheric transport, diagnosed from a carbon monoxide (CO)-like tracer 15 species emitted from global CO sources, are evaluated from an ensemble of four chemistry-climate model (CCMs) contributing to the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). Model time-slice simulations for present-day and end of the 21 century conditions w...

Unlike biological protein pores in lipid membranes, nanopores fabricated in synthetic materials can withstand a wide range of environmental conditions including the presence of organic solvents. This capability expands the potential of synthetic nanopores to monitor chemical reactions occurring at the interface between solutions of organic and aqueous character. In this work, nanopores fabricat...

A hydraulic jump is a flow singularity characterised by a significant amount of air entrainment in the shear zone. The air is entrapped at the jump toe that is a discontinuity between the impinging flow and the roller. The impingement point is a source of air bubbles, as well as a source of vorticity. Herein the convective transport of air bubbles in the jump roller is re-visited. Some analytic...

Lithium is an excellent tracer of mixing in stars as it is destroyed (by nuclear reactions) at a temperature around ∼ 2.5 × 10 K. The lithium destruction zone is typically located in the radiative region of a star. If the radiative regions are stable, the observed surface value of lithium should remain constant with time. However, comparison of the meteoritic and photospheric Li abundances in t...

In natural waterways and estuaries, the understanding of turbulent mixing is critical to the knowledge of sediment transport, stormwater runoff during flood events, and release of nutrient-rich wastewater into ecosystems. In the present study, some field measurements were conducted in a small subtropical estuary with micro-tidal range and semi-diurnal tides during king tide conditions: i.e., th...

Simple, one-zone models for inhomogeneous chemical evolution of the Galactic halo are used to predict the number fraction of zero-metallicity, Population III stars, which currently is empirically estimated at < 4 × 10. These analytic models minimize the number of free parameters, highlighting the most fundamental constraints on halo evolution. There are disagreements of at least an order of mag...

We consider the flow of two immiscible fluids of different mobility in a porous medium. If the more mobile fluid displaces the other, a macroscopically sharp interface is unstable. By growing a network of fingers on a mesoscopic scale, the two phases mix on a macroscopic scale. We are interested in the evolution of this mixing zone. We show that the effect of a large but finite mobility ratio λ...