Instability of a compound liquid jet

In the linear Rayleigh theory [1] the degree of stability of a jet is determined by the viscosity and inertia characteristics of the fluids and the interphase surface tension. The stability of a jet in an infinite medium increases with increase in the viscosity of both the jet and the medium [2, 3]. The presence of two interfaces is responsible for various features of the development of instability in a liquid layer on the surface of a cylinder, and in particular a layer on the inner surface of a cylinder is more unstable than one on the outer surface [4]. In [5, 6] the breakup of a hollow jet in an external medium was investigated. In this paper we examine, in the linear approximation, the stability of a compound jet of nonmiscible liquids with respect to small axisynmetric perturbations of the interfaces. The instability characteristics are given for jets with inviscid and very viscous outer shells. The conditions governing the suppression of rapidly growing instabilities of the inner part (core) of the jet by a viscous shell are determined.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 3–8, July–August, 1985.     

Two Nonlinear Models of Brittle Fracture for Solids

This paper considers isotropic and orthotropic nonlinear constitutive relations for brittle materials in the case of plane stresses. Numerical solution algorithms based on the finite-element method are developed. The resulting material models are incorporated in the PIONER software. The correctness of crack path determination is examined by solving a test problem of crack propagation. The isotropic model gives mesh-dependent results, whereas the orthotropic model provides an adequate solution. It is shown that solutions obtained for the isotropic model are close to those obtained by eliminating failed elements.     

Drop and Bubble Deformation in an Electric Field

A steady problem of drop (bubble) shape in a uniform electric field is considered when the drop and the surrounding medium are immiscible. The electric-charge transport includes both the ohmic current across the interphase boundary and convective transport over the interface. If there is no convective transport, the drop (bubble) may be transformed into either an elongated or a flattened spheroid. Under these conditions, the sign of the deformation remains unchanged for arbitrary values of the problem parameters. Convective charge transport along the surface initiates additional motion in both the drop and the surrounding medium. However, with increase in the convective-transport intensity the deformed drops display different behavior. The compression of a flattened drop slows and, under certain conditions, compression is replaced by extension. However, an elongated spheroid cannot be transformed into a flattened spheroid. The calculations were performed under the assumption that the drop is convex. It was found that, for both an elongated and a flattened drop, the maximum ratio of the major and minor spheroid axes is 2:1. In experiments with oils, the possibility of both a decrease in the drop compression rate and deformation sign reversal was demonstrated.     

Synthesis of 2,5‐Disubstituted Derivatives of Pyrano[2,3‐d][1,3]thiazines via the Interaction of 2‐Substituted 4‐Hydroxy‐6H‐1,3‐thiazine‐6‐ones with Aldehydes

A new and efficient route for the synthesis of derivatives of the poorly investigated pyrano[2,3‐d][1,3]thiazine heterocyclic system is disclosed. These compounds were prepared via annulation of 2‐aryl‐4‐hydroxy‐6H‐1,3‐thiazine‐6‐ones with aliphatic and aromatic aldehydes in the presence of pyridine. The method is general and versatile, and the interaction is independent on the nature of the aldehyde, the only exceptions being formaldehyde and salicylaldehydes.     

Synthesis of zinc oxide powders in plasma–solution systems

A new method is proposed for the synthesis of powdered zinc oxide with the use of a plasma–solution system. The chemical and phase compositions and the morphology of the synthesized powders have been determined. It has been found that the calcination of powders obtained in the plasma–solution system leads to the formation of ZnO.     

Influence of Type and Configuration of the Atom Probe Tomography Setup with Laser Evaporation on the Data Reconstruction Accuracy

Physics of Atomic Nuclei - Atom probe tomography (APT) is a tool for detailed chemical composition analysis of advanced structural material nanostructure. The use of different Atomic Probe...     

Experimental and Theoretical Study of the Atomic Structure Evolution of High-Entropy Alloys Based on Fe,Cr, Ni,Mn, and Co upon Thermal and Radiation Aging

Physics of the Solid State - A comprehensive experimental–theoretical study of the processes of local ordering of multicomponent alloys has been carried out. Atom probe tomography and...     

Compressibility of Nonideal Deuterium and Helium Plasmas up to 20 TPa

Journal of Experimental and Theoretical Physics - We present our experimental results on the compressibility of strongly coupled (nonideal) degenerate deuterium and helium plasmas...     

Reactions of Ethyl 3-(4-Oxo-4H-chromen-3-yl)prop-2-enoates with 1,2-Binucleophiles

Russian Journal of General Chemistry - Reactions of ethyl 3-(4-oxo-4H-chromen-3-yl)prop-2-enoates with 1,2-binucleophilic agents (hydrazine, phenylhydrazine, hydroxylamine) leads to the formation...     

Inspection of ratcheting models for pathological error sensitivity and overparametrization

Meccanica - Accurate analysis of plastic strain accumulation under stress-controlled cyclic loading is vital for numerous engineering applications. Typically, models of plastic ratcheting are...