Generalized self-consistent method: Modeling and computation of effective elastic properties of composites with composite or hollow inclusions

A new approach to the generalized self-consistent method [1,2] has been developed for problems of the statistical mechanics of composites with composite or hollow inclusions. The approach can reduce the problem of predicting the effective elastic properties of composites to a simpler averaged problem of a single, composite, or hollow inclusion with inhomogeneous elastic surrounding in a homogeneous effective elastic medium. The problem of predicting the effective elastic properties of composites with unidirectional hollow fibers or hollow spherical inclusions are studied by using the new approach.Submitted to the 10th International Conference on Mechanics of Composite Materials, April 20–23, 1998, Riga, Latvia.Perm' State Technical University, Russia. Translated from Mekhanika Kompozitnykh Materialov, Vol. 34, No. 2, pp. 173–183, March–April, 1998.     

Reaction of 3(5) -diazo-1,2,4-triazoles with nitroalkane anions

The 1,2,4-triazolylhydrazones of the corresponding nitro aldehydes were obtained by the reaction of the anions of nitromethane, nitroethane, and 1-nitropropane with diazo-1,2,4-triazoles. 2-Nitropropane, 1,1-dinitroethane, 1,1-dinitropropane, and trinitromethane form 1,2,4-triazolylazonitro compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 713–717, May, 1972.     

A generalized self-consistent method for composites with random elastic properties of inclusions

The generalized self-consistent method is extended to the problems of statistical mechanics of composites with random elastic properties of inclusions. This approach makes it possible to reduce the problem of predicting the effective elastic properties of composites with random structures to a sequence of simpler homogenized boundary-value problems for solitary inclusions with inhomogeneous elastic transition layers in a homogeneous effective elastic medium and with the corresponding boundary conditions. The elastic properties of a solitary inclusion for the gth homogenized problem are found from the solutions of the gth and (g+1)th homogenized problems. The elastic properties and sizes of the transition layers account for the random distribution, random sizes, and random elastic properties of inclusions in the composite. A test problem of predicting the effective elastic properties of a transversely isotropic layer composite with random elastic properties of some layers is solved by using the method proposed. The solution obtained coincides with the known exact solution [1].Perm State Technical University, Perm, Russia. Translated from Mekhanika Kompozitnykh Materialov, Vol. 35, No. 6, pp. 785–796, November–December, 1999.     

A self-consistent statistical mechanics approach for determining effective elastic properties of composites

A self-consistent statistical mechanics approach for determining the effective elastic properties of composites with random structure is developed. The problem is reduced to the model of a single inclusion with a non-homogeneous elastic neighbourhood in a medium with effective elastic properties. The inhomogeneous elastic properties and size of neighbourhood are defined by randomness of the geometry, random size of inclusions and random elastic properties of the inclusions. Numerical results are given for the effective elastic properties of a composite with hollow spherical inclusions.     

Electrokinetic injection of DNA from gel micropads: basis for coupling polony technology with CE separation

We propose a novel method for electrokinetic injection of DNA samples into capillaries from nanoliter gel micropads, deposited on glass slides, which are coated with electroconducting film. Theoretical and experimental proof is presented for the proposed method. The method allows efficient and highly precise injection without physical contact between the gel pad and the capillary. Read length of more than 700 bp at Q20 has been reproducibly demonstrated in fused-silica capillaries using the proposed injection technique. Based on the obtained results we discuss a novel DNA sequencing system which combines DNA amplification and cycle sequencing in arrays of subnanoliter gel micropads and high-throughput electrophoretic separation in monolith multicapillary arrays.     

Generalized self-adjustment method for statistical mechanics of composite materials

A new method is developed for the statistical mechanics of composite materials — the generalized selfadjustment method — which makes it possible to reduce the problem of predicting effective elastic properties of composites with random structures to the solution of two simpler “averaged” problems of an inclusion with transitional layers in a medium with the desired effective elastic properties. The inhomogeneous elastic properties and dimensions of the transitional layers take into account both the “approximate” order of mutual positioning, and also the variation in the dimensions and elastics properties of inclusions through appropriate special averaged indicator functions of the random structure of the composite. A numerical calculation of averaged indicator functions and effective elastic characteristics is performed by the generalized self-adjustment method for a unidirectional fiberglass on the basis of various models of actual random structures in the plane of isotropy.     

Singular approximation of the method of periodic components in statistical mechanics of composite materials

A quasi-periodic model is developed for random structures of composites, when the locations of inclusions are given in terms of random deviations from nodes of an ideal periodic lattice. Solution of the stochastic boundary problem of the theory of elasticity is examined for a quasi-periodic component by the method of periodic components, which is reduced to determination of the field of deviations from the known solution for a corresponding periodic composite. The solution is presented for the tensor of effective elastic properties of a quasi-periodic composite in singular approximation of the method of periodic components in terms of familiar solutions for tensors of the effective elastic properties of composites with periodic and chaotic structures and the parameters of the quasi-periodic structure: the coefficient of periodicity and the tensor of the anisotropy of inclusion disorder. A numerical calculation is performed for the effective transversally isotropic elastic properties of unidirectional fibrous composites with different degrees of fiber disorder.Perm' State Technical University, Russia. Translated from Mekhanika Kompozitnykh Materialov, Vol. 33, No. 4, pp. 460–473, July–August, 1997.     

Hydrolysis of N-Cyanoazoles

The hydrolysis kinetics of N-cyanoazoles in alkaline solutions is described by a first-order kinetic equation with respect to the substrate and concentration of hydroxide ions. The hydrolysis rate constants increase with increasing number of nitrogen atoms in the heterocyclic moiety and decrease with introduction of the annelated benzene ring.     

Reactions of 1-Cyanoimidazole and 1-Cyanobenzimidazole with Aliphatic Alcohols

Alkyl imidazole-1-carboximidates and alkyl benzimidazole-1-carboximidates were synthesized by reaction of 1-cyanoimidazole and 1-cyanobenzimidazole with aliphatic alcohols. The reaction time and the product yield depend on the structure of the alcohol.