We present the results of experiments studying the shape of craters formed by the normal impact of a solid spherical projectile into a deep noncohesive granular bed at low energies. The resultant impact crater surfaces are accurately digitized using laser profilometry, allowing for the detailed investigation of the crater shape. We find that these impact craters are very nearly hyperbolic in pr...

Mechanisms that govern the coexistence of multiple biological species have been studied intensively by ecologists since the turn of the nineteenth century. Microbial ecologists in the meantime have faced many fundamental challenges, such as the lack of an ecologically coherent species definition, lack of adequate methods for evaluating population sizes and community composition in nature, and e...

We extend recent studies of the minimal energy packings of short flexible polymers with hard-core-like repulsions and short-range attractions to include bond-angle interactions with the aim of describing the collapsed conformations of "colloidal" polymers. We find that flexible tangent sticky-hard-sphere (t-SHS) packings provide a useful perturbative basis for analyzing polymer packings with no...

The lifetime of a stored beam due to the Touschek effect is calculated for arbitrary ratios of beam height to beam width. A variation of the beam envelopes is taken into account, i. e. the derivatives of the horizontal and vertical amplitude functions and dispersions are included. The calculation is done for arbitrary energies in the rest frame of the colliding particles.

We used a microcomputer-controlled total ozone portable spectroradiometer instrument #21 (MTOPS21) to measure solar radiation at 298, 304 and 310 nm in Greenbelt, Md., during 1995. One day's ozone measurements from a Brewer instrument (B105) were used to calibrate the 304- and 310-nm channel ratios to a theoretical model. Total ozone estimates were then determined for the entire MTOPS21 data se...

The USDA Healthy Eating Index-2005 (HEI-2005) is a tool to quantify and evaluate the quality of diet consumed by the U.S. population. It comprises 12 components, expressed as ratios of a food group or nutrient to energy intake. The components are scored on a scale from 0 to M, where M is 5, 10, or 20. Ideally, the HEI-2005 is calculated on the basis of the usual dietary intake of an individual....

Contributions of intermolecular electron energy transfers in the electronic quenching are calculated for molecular collisions N2(A6 u , W 1u)+N2(X6 g , v=0), N2(A6 u )+N2(X 16+ g , v≥0), N2(A 36+ u )+O2(X 36− g , v=0– 2), O2(a1g , b16+ g )+O2(X 36− g , v=0–2). The calculation has allowed one to estimate the product branching ratios. It is shown that there is a dependence of the calculated rate ...

In gas-oversaturated solutions, stable surface nanobubbles can exist thanks to a balance between the Laplace pressure and the gas overpressure, provided the contact line of the bubble is pinned. In this article, we analyze how the disjoining pressure originating from the van der Waals interactions of the liquid and the gas with the surface affects the properties of the surface nanobubbles. From...

ABSTRACT In this work, the dry reforming of methane was studied using a corona and glow discharge plasma microreactors. A chemical kinetic model was developed to understand the reaction better. The modelization allowed prediction of the reactants conversion according to the energy transfer to the gas (P×τ). The β value is trait of the energy cost, whatever this value was leeser indicated ...