Exact Solutions for Large Amplitude Waves in Dispersive and Dissipative Systems

This paper describes some applications of a transformation which takes a system of two, first order, quasilinear, partial differential equations in two dependent and two independent variables into a similar system. Typically, the equations govern wave propagation in dispersive and dissipative systems. It is shown that certain nonlinear equations which are of current practical interest can be transformed into linear equations.     

Structure of high spin states in83Y

We report on the first in-beam study of high spin levels in⁸³Y which were established up to 9.0 MeV excitation energy and probable spin of 41/2⁺ resp. 27/2^? by means of the reaction⁵⁸Ni(²⁸Si, 3p). Ten lifetimes and six lifetime limits in the 10^?12–10^?9 s range were determined in two recoil distance Doppler shift experiments. The positive parity yrast states form ag _9/2 Coriolis decoupled band with partial alignment, near-rigid rotor moment of inertia and deformationβ ₂=0.29. The negative parity yrast band has very similar collective properties; it shows a pronounced band crossing at rotational frequency ?ω≈0.40 MeV which we associate with twoquasiparticleg _9/2 proton alignment. At 2.56 MeV excitation, a second ΔI=1 band starting with 17/2^? was found. On the basis of the similarity to⁸⁵Y and the very weakE2 decay of this state, we suggest that this band has (3qp) configuration with an alignedg _9/2 neutron pair. The lifetimes of the lowest 2⁺ and 4⁺ state in⁸⁴Zr populated in the reaction⁵⁸Ni (²⁸Si, 2p) were determined to be τ(2)=17.8(11) ps resp. τ(4)=3.5(4) ps.     

Structure of 136Te and the problem of mass of 134Te

Neutron-rich, N=84 nuclei from the ₁₃₂Sn region, populated in spontaneous fission of ₂₄₈Cm, have been studied with EUROGAM 2. Excited states and their spins and parities in the ₁₃₆Te nucleus were established up to 17ħ. OXBASH code calculations support the experimental identification of maximum aligned configurations in ₁₃₆Te. Empirical shell model calculations for the I_π= 14₊ level in ₁₃₆Te indicate that the adopted mass of the ₁₃₄Te nucleus should be lowered by 200(80) keV. Received: 3 August 1998     

Three-valence-particle fission product 51 135Sb84

By analysis of fission product γ-ray data measured at Eurogam II using a ₂₄₈Cm source, yrast levels up to about 2 MeV in the N=84 three-particle nucleus ₁₃₅Sb have been identified. These levels are interpreted as π g^7/2ν f^7/2 ₂ and π g^7/2ν f^7/2h^9/2 states with the help of shell model calculations using empirical nucleon-nucleon interactions. Received: 30 July 1998     

Errata

A numerical error was made in estimating an El transition strength in ⁶⁴Ge. Correction of the error indicates isospin mixing is similar to that found in beta decay experiments in this mass region.     

Zeta potential measurement for air bubbles in protein solutions

Protein adsorption at gas-liquid interfaces is important in a number of processes including foam formation in bioreactors, foam fractionation for protein recovery, and production of protein based food and drinks. The physical properties of the gas-liquid interface will influence foam stability; important properties will include both surface rheological and electrokinetic properties. While surface rheological properties of gas-protein solution interfaces have been reported, there are no published values for electrokinetic properties at such interfaces. In this paper, zeta potential values of gas bubbles in solutions of three proteins, measured using a microelectrophoresis technique, are reported. The three proteins chosen were BSA, beta-casein, and lysozyme; these proteins have all been used previously in protein foaming studies. The effect of protein concentration and ionic strength is considered. For BSA and beta-casein, zeta potential was found to increase with increasing protein concentration and ionic strength. For air bubbles in lysozyme solutions, measured zeta potential was zero. zeta potential values for air bubbles in some binary protein mixtures are also presented.