Stability at Random Close Packing

The requirement that packings of hard particles, arguably the simplest structural glass, cannot be compressed by rearranging their network of contacts is shown to yield a new constraint on their microscopic structure. This constraint takes the form a bound between the distribution of contact forces P(f) and the pair distribution function g(r): if P(f) \sim f^{\theta} and g(r) \sim (r-{\sigma})^(-{\gamma}), where {\sigma} is the particle diameter, one finds that {\gamma} \geq 1/(2+{\theta}). This bound plays a role similar to those found in some glassy materials with long-range interactions, such as the Coulomb gap in Anderson insulators or the distribution of local fields in mean-field spin glasses. There is ground to believe that this bound is saturated, offering an explanation for the presence of avalanches of rearrangements with power-law statistics observed in packings

Cooperative jump motions of jammed particles in a one-dimensional periodic potential

Cooperative jump motions are studied for mutually interacting particles in a one-dimensional periodic potential. The diffusion constant for the cooperative motion in systems including a small number of particles is numerically calculated and it is compared with theoretical estimates. We find that the size distribution of the cooperative jump motions obeys an exponential law in a large system.Comment: 5 pages, 4 figure

Methods of averages expansions for artificial satellite applications

Formulas derived for averaged potential in artificial satellite theor

TT-adic exponential sums of polynomials in one variable

The $T$-adic exponential sum of a polynomial in one variable is studied. An explicit arithmetic polygon in terms of the highest two exponents of the polynomial is proved to be a lower bound of the Newton polygon of the $C$-function of the T-adic exponential sum. This bound gives lower bounds for the Newton polygon of the $L$-function of exponential sums of $p$-power order

Compositions and medical devices for controlled release of nitric oxide and methods of production thereof

The present disclosure describes compositions providing for controlled release of nitric oxide (NO) and methods for production of these compositions. In some embodiments, the compositions may include a biodegradable polymer and a nitric oxide-releasing material at least partially encapsulated by the biodegradable polymer. Nitric oxide-releasing materials may include, for example, diazeniumdiolates and nitric oxide contained within a zeolite, metal-organic framework or other porous material. In general, the compositions are spun into a porous fiber, which may be further annealed by heating in order to densify the fiber. Annealing may prolong the NO release profile. Medical devices containing the compositions described herein are also contemplated by the present disclosure. Medical devices include, for example, textiles, bandages and articles of clothing.Board of Regents, University of Texas Syste