Rational approximation of distributed parameter systems

A new approach to the construction of approximate models is proposed and justified for a wide class of distributed and lumped parameter systems. The approach is based on the iterative identification method that is especially efficient under uncertainty and errors in available data. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 99–116, March–April 2008.     

Effect of Liquid Inertia and Wall Porosity on the Process of Momentum Transfer in a Biobearing With Injection of a Lubricant

We consider the flow of a compressed Newtonian fluid in a biological bearing that has a porous wall, i.e., in a hip joint. The system is modeled by two curvilinear surfaces and a porous wall bounded by a curved impermeable surface. The flow in the gap is considered with account for inertia forces. The Navier–Stokes and Poisson equations used are separated with the aid of the MorganCameron approximation. A solution which relies on the averaging of inertia forces is obtained in a closed form. A bearing of spherical shape is considered as an example.     

Pyrolysis of Complexes of Metallosulphophthalocyanines with Chitosan for Obtaining Graphite-Like Structures

Journal of Inorganic and Organometallic Polymers and Materials - The pyrolysis of chitosan and its polymeric complexes with metal phthalocyanines was studied by thermochemical and spectral methods....     

Molecular characteristics of polymerized surfactants: influence of introduced crosslinking agent and monomer concentration

Polymerizable surfactants are currently attracting considerable interest due to their promising applications in various fields of science and engineering. The present work is devoted to studies of crosslinked poly(N‐acryloyl‐11‐aminoundecanoic acid) and sodium poly(N‐acryloyl‐11‐aminoundecanoate) that were synthesized in reaction mixtures of various compositions (i.e. with different amounts of a crosslinking agent and monomer concentrations). The products were studied by viscometry, dynamic light scattering, sedimentation velocity ultracentrifugation, flow birefringence as well as equilibrium and non‐equilibrium electric birefringence. It was established that both intramolecular and intermolecular crosslinks are formed in the polymerization process. Molecular optical methods and electro‐optical methods were used to determine the sizes of macromolecules with intramolecular crosslinks and the structures containing intermolecular crosslinks that were prepared at various concentrations of the monomer and the crosslinking agent. It was demonstrated that a simultaneous decrease in the amount of the crosslinking agent and decrease in the initial monomer concentration during the synthesis resulted in a reduction in the number of intramolecular crosslinks and molecular masses of the synthesized crosslinked macromolecules. © 2019 Society of Chemical Industry