Measurement of forming trajectories during drilling

Results are provided for an experimental study of forming trajectories during drilling and the effect on them of cutting speed and drilling depth. __________ Translated from Izmeritel’naya Tekhnika, No. 8, pp. 31–33, August, 2006.     

Epoxy-Polysulfone Networks as Advanced Matrices for Composite Materials

Compatibility between polysulfone (PSF) and epoxy oligomers in the melt state as well as the morphology and properties of alloys obtained were studied as a function of composition. The compatibility depends on the length and structure of epoxy molecules, and is best in the case of epoxysulfone oligomers (ESO).

The properties of hybrid matrices are determined by their composition and morphology. The most pronounced effects are observed in the regions of small concentrations of either component. A small quantity of PSF significantly improves thermal stability and heat resistance of the epoxy resin as well as its impact strength. On the other hand, on addition to PSF of small amounts of epoxysulfone oligomers, the processability of the matrix can be substantially improved. In particular, the melt viscosity decreases, and wetting and impregnation of fibrous reinforcement is facilitated. Besides, the matrix adhesion to fibers is increased.

Powdered PSF/ESO/curing agent mixtures are good for application in solvent-free technological processes of fibrous composites production, e.g. in electrostatic deposition of matrix particles onto a reinforcing fabric. Plastics based on hybrid matrices are distinguished by improved strength.     

Control of properties of PZT ceramics during liquid-phase sintering

A PZT ceramic modified by 0.4Pb-(1–x)(B₂O₃)–x(GeO₂) glass, and glass-ceramics modified by V₂O₅, have been obtained. The influence of the chemical composition of the glasses on the mechanical strength and dielectric parameters of these ceramics is investigated. The mechanical and electrical parameters of PZT ceramics are considerably improved by small additions of glass ( 1 mass %) of suitable composition. During heat treatment, the mobility of the domain walls may be changed as a result of the interaction of smelt glass with the surface layer of the crystallites (resulting from a change of V _Pb ^t" vacancy concentration in grains and decreased mechanical tension on the grain boundaries). By introducing the glass, we can decrease the porosity of the ceramics and thus decrease the attenuation of surface acoustic waves in piezoelectric filters. The origin of the liquid phase during sintering of the PZT glass-ceramics prevents PbO evaporation. This determines the preservation of the solution's stoichiometry. The glass addition leads to a decrease in the sintering temperature of PZT, which simplifies the technological process. The glass ceramics are obtained by common ceramic technology which is used for commercial piezoceramic production. The main technological problem is choosing the chemical composition and concentration of the glass and thermal process parameters.     

Experimental measurements of optical constants of metals in the two-temperature state

Complex permittivity of metals being in the two-temperature state of electron and ion sub-systems excited by the femtosecond laser pulses is measured. Diagnostics of the optical properties was performed in the sub-picosecond range, in the visible spectral range at the wavelengths of 800, 620, and 400 nm for gold, silver, nickel, and vanadium under electron sub-system heating up to 10–30 kK.     

Multi-channel control system design for a robot manipulator based on the time-scale method

The problem of controller design for nonlinear multi-channel dynamical plants is discussed. Trajectory motion tracking control for a multilink manipulator is treated as an example of the proposed design methodology. A distinctive feature of the discussed approach to calculate controller parameters is that two-time-scale motions are artificially forced in a closed-loop system where stability of the fast mode is provided by selection of the controller parameters while the induced slow mode correspond to the reference model of desired nonlinear plant behavior. Simulation results for a two-link manipulator robot manipulator tracking control system are presented..     

Drive-crank load for a continuous mechanical transformer

The drive-crank load is calculated for a continuous mechanical transformer. Its magnitude and direction are determined with respect to a crank with a specific working radius.     

Decomposition temperature and mechanism of polymer materials in arc-discharge plasma jet

The decomposition temperatures of disperse polymers moving in a plasma jet are determined. The mechanism of thermal destruction is discussed, as well as the influence exerted by physical factors in the fast heating of polymer materials in conditions of nonsteady ablation.Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 61, No. 5, pp. 763–769, November, 1991.