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Temperature of the fcc-bcc (face-centered cubic – body-centered cubic) solid-solid phase transition in Fe calculated as Teq = Tinst ΔEfcc-bcc/ΔEbcc-m. (where m. stands for martensitic mixture that bcc-Fe converts into at Tinst) maps out a curve which is consistent with the line of the fast recrystallization threshold observed in the recent experiments on Fe at ESRF.
Density field from 2 sets of Direct Numerical Simulations of the immiscible Rayleigh-Taylor instability using our new generalized Cahn-Hilliard Navier-Stokes methodology. The surface tension is larger in the bottom simulation and is close to the cut-off above which the instability does not grow.
Navier-Stokes equations are numerically solved using the CFDNS code, without any turbulence model or shock-capturing/fitting schemes. Whole range of spatial and temporal scales of the turbulence are resolved. Shock wave structure resolved as a solution to the N-S equations.
Investigation of pyrocumulus column collapse. Effects of fuel heterogeneities on fire spread. Role of vorticity in fire rate of spread.
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Our primary use of the institutional computing clusters has been for Wikipedia-based disease surveillance and forecasting work. We've expanded breadth: the number of diseases and locations that can be surveilled using internet data. We've expanded forecasting: surprisingly little work towards forecasting disease spread with quantified uncertainty. We've expanded big data processing techniques: the Wikipedia access logs are 5TB of compressed text; we're working on efficient ways to process and store time series. Our work received significant media coverage and was highlighted as LANL's best science story of 2014.
Phonon spectra at two different densities of bcc-Be at T slightly below the corresponding Tm. At P=0 the system is dynamically unstable at low T but stabilizes at T close to Tm=1560 K. However, unless the system size is 1458 atoms or higher (the number of valence electrons is ~ 3000 or more) dynamic instability is still present, in the form of an imaginary phonon branch at the Γ- point (Fig. 1). At P=300 GPa the system is dynamically stable for as low as 128 atoms (Fig. 2). This example demonstrates that at present it is unfeasible to treat bcc-Fe in the region of its dynamic instability (megabar pressure range) with the existing first-principles software (e.g., VASP) which only allows treating bcc-Fe with up to ~ 500 atoms (~7000 valence electrons).
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Two sets of simulations were performed within this allocation: 1) a 12-year fully-coupled experiment in pre-industrial conditions, using the CICE4 version of the sea-ice model; 2) a set of multi-decadal ocean-ice-only experiments, forced with CORE-I atmospheric fields and using the CICE5 version of the sea-ice model.
Whole cell biosensors (WCBs) utilize an organism’s natural ability to sense and respond to the environment. Through implementation of two different protein engineering methods, I seek to develop a WCB for the detection of important chemical signatures in the environment. I will reengineer the ligand binding profile of proteins known to alter transcription of genes, and I will engineer signal transduction in proteins already known to bind relevant compounds. In both cases, detection of compounds of interest will lead to the production of a measurable fluorescent signal within the organism. These approaches will provide the groundwork for the development of novel chemical sensing technologies that provide a cheap and efficient alternative to traditional methods for detection of compounds.
Data are plotted for densities from 2 to 6 g/cc.
The main objective of SHIELDS project is to develop a new capability to understand, model, and predict the spacecraft Surface Charging Environment (SCE).
This document presents a diagram of the beam and other specifics related to the MaRIE project at LANL.