The use of a high-modulus-inclusion gage in nonlinear viscoelastic materials

The behavior of an inclusion in a host material subjected to a stress system depends primarily on the ratio of the tangent moduli,E inclusion/E host. An inclusion of suitable material used in the form of a gage will give an identifiable photoelastic-fringe pattern. This pattern is related to the applied biaxial stresses in the diametral plane of the gage, and is independent of the actual modulus and strains in the host material provided that the moduli ratio is more than 300. A program of work has been carried out to verify the use of such an inclusion gage in low-modulus nonlinear viscoelastic materials. The gage geometry used in this work consisted of a hollow cylinder of birefringent material with a ratio of outside diameter to inside diameter of 5 to 1. The host materials were either unfilled or highly filled carboxyl-terminated polybutadiene rubbers. The moduli ratios for both host materials were such that the gages act as rigid inclusions. A theoretical study has also been conducted to find the optimum measuring points within the gage and the fringe patterns created by selected biaxial-stress ratios. The study also showed that the gage sensitivity is virtually independent of Poisson's ratio but depends on the biaxial ratio of the stresses. The values of the sensitivity factor obtained experimentally were close to those derived theoretically. The stressfringe order at the optimum measuring points was obtained by Tardy compensation, and the biaxial-stress ratio determined either from fringe-pattern recognition or by measuring points. Future applications and uses of such a stress-measuring technique will be described.     

A new microstructure-based constitutive model for human blood

A new constitutive equation for whole human blood is derived using ideas drawn from temporary polymer network theory to model the aggregation and disaggregation of erythrocytes in normal human blood at different shear rates. Each erythrocyte is represented by a dumbbell. The use of a linear spring law in the dumbbells leads to a multi-mode generalized Maxwell equation for the elastic stress and both the relaxation times and viscosities are functions of a time-dependent structure variable. An approximate constitutive equation is derived by choosing a single mode corresponding to the cell aggregate size where the largest number of cells are to be found. This size is identified in the case of steady flows. The model exhibits shear-thinning, viscoelasticity and thixotropy and these are clearly related to the microstructural properties of the fluid. Agreement with the experimental data of Bureau et al. [M. Bureau, J.C. Healy, D. Bourgoin, M. Joly, Rheological hysteresis of blood at low shear rate, Biorheology 17 (1980) 191–203] in the case of a simple triangular step shear rate flow is convincing.     

Misting of non-Newtonian liquids in forward roll coating

Misting of liquids in forward roll coating is a problem under certain conditions. The relaxation time is known to influence misting but the fundamental mechanisms are not clear. A new mechanism for misting of dilute non-Newtonian liquids was proposed based on visualizations with a high-speed camera. With these liquids, filaments were created which sometimes transformed into beads-on-string structures and the beads were ejected as mist droplets when the structures broke. Misting was quantified by measuring sizes of the generated droplets, their count and mass concentration. The measurements were related to elasticity of the solutions through their relaxation times. Small levels of elasticity reduce the amount of misting, but higher levels lead to an increase.     

A novel synthesis of 1,2-diphosphorylbenzenes

Synthesis of phosphorylchloroacetylenes, diphosphorylacetylenes and the Diels-Alder reactions of the latter to produce $\text{o}$-diphosphorylbenzenes are described.     

Determination of boron in geological materials by inductively-coupled plasma emission spectrometry

Determination of boron in international silicate reference materials with an argon plasma is demonstrated. Detection limits are about 5 ppm for rock samples.     

Polarization in inclusive reactions

A formalism for discussing the spin dependence of inclusive reactions is presented. The role of various constraints following from conservation of parity and angular momentum conservation is discussed. Expressions for specific single and double polarization observables are presented. Predictions of the triple-Regge model for these observables are given.     

Amplitude analyses of the reactions π+p → (ϱ0, ω) Δ++ at 7.1 GeV/c

New data are presented, in the form of statistical tensors, for the reactions π⁺p → (?⁰, ω)Δ⁺⁺ at 7.1 GeV/c. Using these data, two types of model-dependent amplitude analyses have been performed. Both analyses, though based on different sets of assumptions, yield results which are in agreement with each other. The structure observed in the magnitudes and phases of the extracted amplitudes is consistent with that expected on the basis of currently accepted phenomenological ideas.     

On the determination of bond angles of triatomic radicals from electron spin resonance

The s and the p density of the sp hybrid orbital of the unpaired electron on the central nucleus of CO^?₂ and BF₂ are calculated as a function of the bond angle by the INDO molecular orbital method. The theory yields a dependence of the ratio of the p density to the s density on bond angle markedly different from a dependence derived from the orthogonality of sp hybrid orbitals and commonly used to determine the bond angle from ESR data.     

A study of inclusive vector meson production

Data are presented on the reactions π⁺n → ?⁰+X and $\text{K}{}^{\mathrm{?}}\text{p}\text{→}\text{K}{}^1\text{0}\text{(890)+}\text{X}\text{at 6.0}\text{and}\text{7.3}\text{GeV}\text{/c}$, respectively. Comparisons are made with related reactions at higher energies.