United States Department of Energy

About: United States Department of Energy is a government organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Coal & Catalysis. The organization has 13656 authors who have published 14177 publications receiving 556962 citations. The organization is also known as: DOE & Department of Energy.

Study of the ability of multiphase continuum models to predict core-annulus flow†

Abstract: We use the well established core-annulus flow regime as a numerical benchmark to evaluate the sensitivity of gas–solids continuum models and boundary conditions to model formalisms and parameters. By using transient, 1D, grid-independent numerical solutions, we avoid the use of speculative closure terms and show that the kinetic theory of granular flow (KTGF) is sufficient to model core-annulus regime. That regime arises in the time-average solution as a consequence of the fluctuating motion of regions with high solids concentration. These fluctuations are most sensitive to the gravitational acceleration (g) and granular energy dissipation terms. The fluctuation frequency is α . The effect of fluctuations is so dominant that decreasing the restitution coefficient (KTGF parameter) actually increases the average granular temperature. The wall boundary conditions for solids momentum and granular energy equations dictate the core-annulus flow regime. They must cause a net dissipation of granular energy at the wall for predicting that regime. © 2007 American Institute of Chemical Engineers AIChE J, 2007

Method for rapid base sequencing in dna and rna

Abstract: A method is provided for the rapid base sequencing of DNA or RNA fragments wherein a single fragment of DNA or RNA (40) is provided with identifiable bases (A, C, G) and suspended in a moving flow stream. An exonuclease (20) sequentially cleaves individual bases from the end of the suspended fragment. The moving flow stream (24) maintains the cleaved bases in an orderly train for subsequent detection and identification. In a particular embodiment, individual bases forming the DNA or RNA fragments are individually tagged with a characteristic fluorescent dye. The train of bases is then excited to fluorescence with an output spectrum characteristic of the individual bases (26). Accordingly, the base sequence of the original DNA or RNA fragment can be reconstructed.

Measurement of Two Kinds of Granular Temperatures, Stresses, and Dispersion in Bubbling Beds

Abstract: A CCD camera technique was developed to measure instantaneous particle velocities in a thin bubbling bed for fluidization of 530 μm glass beads. The hydrodynamic velocities were computed by averaging the instantaneous velocities over the velocity space using the concepts of kinetic theory. Laminar-type kinetic stresses and granular temperatures were computed from the measurement of instantaneous velocities. Bubblelike granular temperatures were computed from the hydrodynamic velocities. The measured Reynolds normal stresses per unit bulk density in the vertical direction were 8 times larger than the measured Reynolds normal stresses per unit bulk density in the lateral direction because of higher velocity fluctuations for particles in the bubble-flow region. The sum of the measured shear stresses was equal to the pressure drop minus the weight of the bed of solids within experimental error. The restitution coefficients for 530 μm glass beads, estimated from the ratio of shear to normal stresses, are in th...

Schrödinger equation from an exact uncertainty principle

Abstract: An exact uncertainty principle, formulated as the assumption that a classical ensemble is subject to random momentum fluctuations of a strength which is determined by and scales inversely with uncertainty in position, leads from the classical equations of motion to the Schrodinger equation.