Solid-state structure of copper complexes of N-(2-carboxyethyl)chitosan

The sorptivity for ions of the Irving-Williams series (Zn2+, Cu2+, Co2+, Ni2+) was estimated for the chelate sorbent N-(2-carboxyethyl)chitosan cross-linked by nanosecond electron-beam irradiation. The maximum capacity reaches 3.7 mmol/g using a mixture of the appropriate sulfates at pH 4.5. The selectivity of copper sorption is 80%. The structure of the coordination sphere of the copper complexes with N-(2-carboxyethyl)chitosan was investigated by ESR spectroscopy

Model For The Dynamics Of A Bubble Undergoing Small Shape Oscillations Between Elastic Layers

A model is presented for a pulsating and translating gas bubble in a channel formed by two soft elastic parallel layers. The bubble is free to undergo small shape deformations. Coupled nonlinear second-order differential equations are obtained for the shape and position of the bubble, and numerical integration of an expression for the liquid velocity at the layer interfaces yields an estimate of their displacement. Simulations reveal behavior consistent with laboratory observations.Applied Research Laboratorie

Nonlinear Torsional Wave Beams

An evolution equation with cubic nonlinearity is presented for a torsional wave beam in an isotropic elastic solid. Analytical solutions are presented for the fundamental and third harmonic in the far field of a uniform circular source. Numerical results are presented for harmonic beam patterns at an intermediate distance between the near and far fields, and for a torsional waveform with shocks.Applied Research Laboratorie

Coupled Pulsation And Translation Of A Gas Bubble And Rigid Particle

A nonlinear analytic model describing the interaction of a spherical gas bubble and spherical rigid particle is presented. Both the bubble and particle are free to translate. The model is accurate to fifth order in terms of a nondimensional expansion parameter R/d, where R is a characteristic radius and d is the distance separating the bubble and particle. Numerical simulation results are presented to demonstrate the effects of key particle parameters and an external acoustic source.Applied Research Laboratorie

Acoustic waves: should they be propagated forward in time, or forward in space?

The evolution of acoustic waves can be evaluated in two ways: either as a temporal, or a spatial propagation. Propagating in space provides the considerable advantage of being able to handle dispersion and propagation across interfaces with remarkable efficiency; but propagating in time is more physical and gives correctly behaved reflections and scattering without effort. Which should be chosen in a given situation, and what compromises might have to be made? Here the natural behaviors of each choice of propagation are compared and contrasted for an ordinary second order wave equation, the time-dependent diffusion wave equation, an elastic rod wave equation, and the Stokes'/ van Wijngaarden's equations, each case illuminating a characteristic feature of the technique. Either choice of propagation axis enables a partitioning the wave equation that gives rise to a directional factorization based on a natural "reference" dispersion relation. The resulting exact coupled bidirectional equations then reduce to a single unidirectional first-order wave equation using a simple "slow evolution" assumption that minimizes effect of subsequent approximations, while allowing a direct term-to-term comparison between exact and approximate theories.Comment: 12 pages, v2 correcte

THE ROLE OF THE IBD PE IN THE FORMATION OF THE SYSTEM OF CONTINUOUS PROFESSIONAL EDUCATION OF RUSSIA

The article describes the role of the integrated base department of vocational and pedagogical education in the city of Kemerovo in the formation of the system of continuing professional education in RussiaВ статье описывается роль интегрированной базовой кафедры профессионально-педагогического образования в г. Кемерово в становлении системы непрерывного профессионального образования России

The use of a combination frequency technique to measure the surf zone bubble population

There are great benefits to sizing bubbles using a two frequency technique, which examines the appearance of sum-and-difference signals generated by the interaction between a resonant bubble pulsation and a much higher frequency imaging beam. This paper presents the results from using the technique to size bubbles in the ocean surf zone, and details the pulsation model used to calibrate the returned data such that the height of the bubble scattered signal can be related to the number of resonant bubbles of that size. It also shows how ambiguities and inaccuracies (brought on through turbulence and the substantial off-resonance nature of the signal) which affected earlier oceanic tests using the same method can be identified in the returned signal or removed from the estimate during the data processin

Additional symmetries and solutions of the dispersionless KP hierarchy

The dispersionless KP hierarchy is considered from the point of view of the twistor formalism. A set of explicit additional symmetries is characterized and its action on the solutions of the twistor equations is studied. A method for dealing with the twistor equations by taking advantage of hodograph type equations is proposed. This method is applied for determining the orbits of solutions satisfying reduction constraints of Gelfand--Dikii type under the action of additional symmetries.Comment: 21 page