A film model for the prediction of flooding and flow reversal for gas-liquid flow in vertical tubes

A model is presented which demonstrates that the process of flooding and flow reversal can be explained on the basis of a film mechanism. The model predicts well the gas flow rate at which flooding and flow reversal begins and ends for a given liquid flow rate and the presence of a hysteresis loop between flooding and flow reversal. The predictions of the theory are in satisfactory agreement with experimental flooding data.     

Determination of lysine in protein hydrolyzates using lysine decarboxylase from salmonella hadar

Lysine may be determined in protein hydrolyzates with the aid of lysine decarboxylase contained in cell-free extracts of Salmonella hadar grown under suitable conditions.     

Flow pattern characterization in two phase flow by electrical conductance probe

An improved system of conductance probes is used to identify the flow patterns in two phase horizontal, near horizontal and upward flows. The results show that this system is very well suited to distinguish among flow patterns consistent with visual observations.     

Large time behavior of the heat kernel

In this paper we study the large time behavior of the (minimal) heat kernel k_P^M(x,y,t) of a general time-independent parabolic operator Lu=u_t+P(x,∂_x)u which is defined on a noncompact manifold M. More precisely, we prove that

     

Correlation of finite strain measures

A numerical scheme for correlating any two finite strain measures is given, and situations in which such a scheme might be used are introduced. A check is established by comparison with the Reiner-Hanin solution of the Almansi-to-Hencky conversion. A numerical example is provided.     

Sublimation rate of TNT microcrystals in air

Reliable measurements of the sublimation rate of nonuniform layers of trinitrotoluene (TNT) microcrystals were carried out using a quartz crystal microbalance (QCM). The sample layer was prepared by precipitation of TNT from a well-defined volume of its solution in acetonitrile. The TNT solution was placed on the QCM electrode surface to form the precipitated layer of TNT microcrystals. It is shown that the kinetics of small TNT particles sublimation is controlled by the molecular diffusion in air. The sublimation process is well described by simple diffusion expressions that are discussed in the literature for both individual hemispherical-shaped microcrystals and disk-shaped layers. Expressions describing particle size evolution in time were derived based on this diffusion model. It is shown that the expressions developed can be used to simulate particle sublimation in a wide size range, including very small sub-micrometer particles.     

Hadamard products of product operators and the design of gradient-diffusion experiments for simulating decoherence by NMR spectroscopy

An extension of the product operator formalism of NMR is introduced, which uses the Hadamard matrix product to describe many simple spin 1/2 relaxation processes. The utility of this formalism is illustrated by deriving NMR gradient-diffusion experiments to simulate several decoherence models of interest in quantum information processing, along with their Lindblad and Kraus representations.     

Macroscopic modelling of transport phenomena in porous media. 1: The continuum approach

This is the first of two papers presenting a systematic development of a continuum model of a porous medium and of transport processes occurring in it. The concept of a Representative Elementary Volume (REV) as opposed to any arbitrary volume of averaging quantities at the micro-scale, is quantified. A universal criterion for selecting the size of an REV as a function of measurable characteristics of a porous medium and selected tolerance levels of estimation errors, is developed. The rules of spatial averaging are extended by including the effects of both the configuration of the solid matrix and of interphase transfer phenomena within an REV.     

Radial vibrations of composite piezoelectric ceramic disks

A theory is developed for the radial vibrations of thin disks composed of several piezoelectric ceramic materials bonded at their cylindrical interfaces. Closed type solutions are obtained for the resonant and antiresonant frequency equations, and numerical results are presented for various steel/PZT-4 composite disks. The frequency spectrums and corresponding electromechanical coupling factors are found to be quite sensitive to the heterogeneity of the considered piezoelectric systems.     

Blue fluorescent dye-protein complexes based on fluorogenic cyanine dyes and single chain antibody fragments

Fluoromodules are complexes formed upon the noncovalent binding of a fluorogenic dye to its cognate biomolecular partner, which significantly enhances the fluorescence quantum yield of the dye. Previously, several single-chain, variable fragment (scFv) antibodies were selected from a yeast cell surface-displayed library that activated fluorescence from a family of unsymmetrical cyanine dyes covering much of the visible and near-IR spectrum. The current work expands our repertoire of genetically encodable scFv-dye pairs by selecting and characterizing a group of scFvs that activate fluorogenic violet-absorbing, blue-fluorescing cyanine dyes, based on oxazole and thiazole heterocycles. The dye binds to both yeast cell surface-displayed and soluble scFvs with low nanomolar K(d) values. These dye-protein fluoromodules exhibit high quantum yields, approaching unity for the brightest system. The promiscuity of these scFvs with other fluorogenic cyanine dyes was also examined. Fluorescence microscopy demonstrates that the yeast cell surface-displayed scFvs can be used for multicolor imaging. The prevalence of 405 nm lasers on confocal imaging and flow cytometry systems make these new reagents potentially valuable for cell biological studies.