784 research outputs found
Structure-Dynamics Relationships in Complex Fluids and Disordered Porous Solids Assessed using NMR: Structure-Dynamics Relationships in Complex Fluidsand Disordered Porous Solids Assessed using NMR
A NMR study of the structure-dynamics relationships in heterogeneous materials is presented. In the first part, transport in soft-matter systems is studied using the pulsed field gradient NMR technique (PFG NMR). The molecular crowding effect in biological matter has been addressed using polymer solutions as model systems. By performing ensemble-based diffusion studies, the earlier obtained data on anomalous diffusion have been complemented. The transition to normal diffusion on a larger time scale has been shown. Taking advantages of the NMR approach, transport properties of microemulsions consisting of micellar colloids dissolved in liquid crystals have been investigated. The self-diffusivities measured under equilibrium conditions have shown weak correlations with microscopic ordering and macroscopic phase transitions occurring in the systems under study. The formation of micelles is shown to be decisive for macroscopic separation at the isotropic-nematic transition.
The second part of the thesis covers heterogeneous effects in diffusion for fluids in porous solids, as probed using a combination of NMR diffusometry and structure characterization methods. Ionic liquids have been investigated, revealing a complex behavior under confinement. The attempts to correlate the observed characteristics of the ionic liquids with their internal chemical structure were undertaken. Finally, the series of nanoporous glasses with tunable pore structure characteristics were studied. Strong correlations between their structure and the preparation conditions as well as between the resulting transport properties have been shown
THE DEVELOPMENT OF THE RISK MANAGEMENT MECHANISM FOR INNOVATION PROJECT
It is established that the high probability of emergence of risk situations in the innovation project, requires the implementation of risk management measures. It is noted that there is currently no mechanism for distributing of financial risks between the customer and the executor of the innovation project, that is largely negatively reflected in the desire to invest own funds in innovation. The methodological bases of risk management of innovative activity of the project-oriented organization are offered in the article. With the proposed approach, it is possible to estimate in advance how much the proposed risk management measures can reduce the risk of an innovation project and how this activity will affect on the project's effectiveness in deciding whether to continue or stop the innovation project research. On the basis of the existing characteristics of the risk measures of the innovation project, it can be concluded that the best indicator of the effectiveness of a certain stage of the innovation project by the results of simulation is net present value of the project. It is better to use the probability of receiving an ineffective result of an innovation project at an appropriate stage for assessing of the risk of the innovation project and the decision to continue or stop the innovation project at a certain stage
Improving the evolutionary aerodynamic optimization with bezier-parsec parameterization using population size reduction methods
Rheological Characteristics of Loam Compositions with Mineral Additives of Different Genesis and Morfology
Structural clay products manufacturing is depends on the potential of local raw materials. Shoddy silty loams are the main component of molding mixtures in view of shortage of the quality clays. Therefore, methods for determining the structural characteristics of molding compounds are becoming important. The objective of study is the influence of mineral additives different genesis and morphology at structural characteristics and molding properties of the compounds based on shoddy silty loams. Photometrical sedimentometer FSH-6K and optical microscopy method were used for the determining of granulometric compositions and morphological properties of the additives. Conical rheometer method was used for the determining plastic strength of the moulding compounds. Shear plastometer method was used to determining values of the low elastic, high elastic and plastic deformations. It had defined the optimal values of molding clay compound’s moisture in which molding compositions had being tested. Optimal values of the molding composition’s moisture in which molding compounds has not subjected to negative influences of the gravitational water are equal to 15-19%. Structural constants were calculated for molding compositions based on different kinds of additives. Values of the percent of low elastic, high elastic and plastic deformation were calculated on the grounds of rheological curves. Optimal values of composition’s structural characteristics were accepted from the condition of three types of deformations
Cosmic ray modulation in a random anisotropic magnetic field
Inhomogeneities of the interplanetary magnetic field can be divided into small scale and large scale ones as may be required by the character of the problem of cosmic ray (CR) propagation. CR propagation in stochastic magnetic fields is of diffusion character. The main contribution into the scattering of CR particles is made by their interaction with inhomogeneities of the magnetic field H which have characteristic dimensions 1 of the order of Larmor radius R=cp/eH of particle (p is the absolute value of particle momentum, e is particle charge, c is velocity of light). Scattering of particles on such inhomogeneities leads to their diffusion mostly along a magnetic field with characteristic dimensions of variation in space exceeding the mean free path
Multiprogram Stabilization Problem for the Mathematical Pendulum
In this paper, the model of mathematical pendulum is formulated as a non-linear dynamic system. The equilibrium positions of the dynamic system are obtained as a solution of corresponding problem of multiprogram stabilization. This solution is eventually formalized in a form of Hermit's polynomial
Structural and phase features of ceramics from loam and incinerated sewage sludge ash
The relevance of the work is due to the need to expand the raw material base of the construction industry and develop an effective technology for the disposal of waste from water treatment plants. The purpose of the work was to establish the features of the phase composition and structure of loam ceramics and incinerated sewage sludge ash. The work used differential thermal and X-ray phase analysis, electron microscopy. It has been established that the enrichment of loam by the addition of ash from the incineration of domestic sewage sludge (DSS) ensures the connection of aggregates and individual particles into a single system reinforced with anorthite crystals. In this case, an increase in the amount of the anorthite phase and the mechanical strength of ceramics occurs with an increase in the proportion of ash from the incineration of DSS in the charge to more than 20 %. It is shown that the structure of ceramics made from loam with the addition of ash from the combustion of DSS is characterized by a spatial frame, which is a kind of a matrix that combines filler particles according to the "core-shell" type, and an increase in the number of reserve pores, which favorably affects the frost resistance of ceramics
- …