The structure and morphology of aqueous dispersions, the gelation, and the intermolecular interactions of water molecules with a Synthanol ALM-10 non-ionic low-molecular surfactant have been ...investigated using viscosimetry, thermogravimetric analysis, IR spectroscopy, and phase-contrast and polarization optical microscopy in the entire range of concentrations (from 0 to 100 wt %). The polymorphism and polydispersity of Synthanol ALM-10 micelles have been detected. We have determined the gelation mechanism in aqueous dispersions containing from 40 to 70 wt % of amphiphilic molecules. It is found that an increase in the concentration in Synthanol ALM-10 dispersions is accompanied, first, with the formation of inverse micelles of the surfactant, followed by sequential alteration of lyotropic mesophases with the hexagonal symmetry and new forms of bound water associated with the formation of clathrate hydrates. The viscosity of the system increases significantly in this case. At high concentrations of Synthanol ALM-10 (exceeding 70 wt %), inverse micelles are mainly observed.
We use ab initio calculations to analyze the influence of 4d and 5d transition metal alloying elements on cohesive properties of the bulk and a representative grain boundary in Cr within the ...framework of the Rice–Thomson–Wang approach. The results obtained for Cr are combined with the analogous results for Ni to select Ta and Nb as promising alloying additions to dual-phase (α/γ) Cr-Ni-base high-temperature alloys. Ta and Nb are added to the alloying system of an existing alloy I (Cr-Ni-W-V-Ti) in an attempt to design a chemical composition of a new alloy II (Cr-Ni-W-V-Ti) + (Ta-Nb). Investigation of the microstructure of the Ta-bearing Cr-Ni-alloy reveals a Ta enrichment of large γ-areas near GBs in α-matrix that we consider as potency to increase the cohesive strength of GBs and the cohesive energy of the bulk in γ-phase. Mechanical testing of alloys I and II demonstrates that the alloy II has improved tensile strength and creep resistance at high temperatures.
The effect of radical polymerization inhibitors on the aggregative stability of latexes of styrene copolymers with acrylonitrile and ethoxyethyl acrylate, prepared with Sintanol ALM-10 nonionic ...emulsifier, was studied. Stable free macroradicals can be one of the factors responsible for the loss of the aggregative stability of the latexes. The mechanism of the action of macroradicals on the adsorption layer of polymer–monomer particles was suggested, and the stabilizing power of naphthalene-containing dispersants was accounted for on the basis of this mechanism.
On the example of model systems (polystyrene latexes and copolymers of styrene with polar monomers, acrylonitrile and ethoxyethyl acrylate), the effect of sodium naphthyl formaldehyde sulfonate on ...the aggregative stability of synthetic latexes was analyzed. Upon reaching the limit conversion, these latexes during storage spontaneously transfer to a solid gel having a periodic colloidal crystal-like structure. It is shown that the gelation process obeys the Smoluchowski law for coagulation. An increase in the molecular weight of the polymer and in the size of the latex particles during the formation of the gel was recorded. The introduction of a NF dispersing agent neutralizes the gel effect, stabilizes the system, prevents gelation and leads to a slight increase in the molecular weight of the polymer and the degree of polydispersity of the polymers obtained. It has been suggested that stable macroradicals accumulating from the gel-effect stage and remaining in the system after completion of polymerization can be one of the reasons for the loss of aggregative stability of latexes, and incorporating the dispersing agent into the adsorption layer of polymer-monomer particles leads to the recombination of these radicals within the particle and the stabilization of latexes in the polymerization process.
The presence of “living” macroradicals in the volume of a polymer–monomer particle may be one of the factors responsible for the loss of the aggregative stability of latexes. If the adsorption ...protection of a polymer–monomer particle is insufficient, high content of “living” macroradicals leads to gelation in the latex in the course of storage. Correlation between the latex life time, hydration of nonionic surfactant molecules in the adsorption layer of a polymer–monomer particle, and extent of the action of the macroradicals was determined. Naphthalenesulfonic dispersing agents enhance the stability of latex systems in the step of polymerization and distillation of the monomers owing to a decrease in the critical micelle concentration of the emulsifier, to extension of the micellar period of the polymerization, to an increase in the degree of saturation of polymer–monomer particles, and to an increase in the probability of macroradical recombination in the volume of a polymer–monomer particle. With an increase in the degree of polycondensation of naphthalene-containing dispersing agents, their surface activity increases, whereas the ability to support the aggregative stability of latexes decreases.
We used the results of ab initio calculations to improve the high temperature mechanical properties of a Cr-Ni-base alloy (Cr-33Ni-2W-0,3Ti-0,3V, wt.%) (alloy I) with two-phase α - γ microstructure. ...It was established that γ – phase in Cr-Ni-base alloy (I) plays a key role in the processes of plastic deformation. By analogy with Ni-base superalloys the bulk and grain boundaries cohesion in γ – phase of the Cr-Ni-base alloy (I) were strengthened by adding a package of the “low alloying” elements (Zr, Hf, Nb, Ta) (alloy II) chosen in accordance with our theoretical predictions. We further investigated an influence of a sum (Ta, Nb, Hf, Zr) like the low alloying additions on the mechanical properties of Cr-Ni-base alloy (I). The results of mechanical testing revealed a significant strengthening of the alloy (II) in comparison with (I) at the temperature 1080 oC in accordance with our predictions. We also investigated the microstructure’s peculiarities of the alloys (I) and (II).
The use of balanced multicomponent supplements is highly promising. In this regard, we believe it will be relevant to use a balanced carbohydrate complex under the trade names Felucene K 2-4 and ...Felucene K 2-6 for agricultural animals of a specified age in accordance with the instruction for use. The inclusion of the studied supplements in the ration of young cattle in various doses made it possible to trace changes in growth and development of young Hereford breed. The experiments showed the best result demonstrated by animals of experimental group III, who received the supplement K 2-4 at a dose of 100 g and K 2-6 at a dose of 150 g per animal per day, respectively. Further research is planned to study post-slaughter indicators in order to assess the quality of meat products.
In this work, the interatomic potentials for modeling diffusion in the C15 Cr2Ta Laves phase were constructed within the N-body approach. The potential for Ta–Ta interactions reproduces the lattice ...parameter, cohesive energy, elastic constants, equation of state, thermal expansion, point defect energies, and phonon dispersion of body-centered cubic Ta in qualitative agreement with density functional theory (DFT) data and almost quantitative agreement with available experimental data in the temperature range of stability of C15 Cr2Ta Laves phase. The potential for Cr–Ta interactions reproduces the elastic constants, point defect properties, equilibrium volumes, and formation enthalpies of Cr–Ta structures in qualitative agreement with DFT data. Also, it reproduces the lattice stability and high-temperature formation enthalpy of C15 Cr2Ta Laves phase in very close agreement with the available experimental data. The calculations of diffusion coefficients with constructed potentials showed that diffusion in C15 Cr2Ta lattice is governed by Cr atoms which cannot move without creation of vacancies. The constructed potentials can be used in further investigations of diffusion processes in Cr–Ta phases at temperatures up to 2000 K, while the obtained results on diffusion coefficients in C15 Cr2Ta Laves phase would be useful in the rational design of Cr–Ta based alloys.
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Multicomponent nanostructured (Ti-Zr-Hf-V-Nb)N coatings produced by the cathodic-arc-vapor-deposition method have been studied using several complementary methods of elemental and structural ...analysis, such as those based on the use of slow positron beam (SPB); proton microbeam (μ-PIXE); electron micro- and nanobeam (EDS and SEM analysis); and X-ray diffraction phase analysis (XRD), including the
a
-sin
2
ϕ method of measuring the stress-strain state (X-ray tensometry). The elemental composition, microstructure, residual stresses in nanograins, and in-depth and surface distributions of defects and atoms, as well as the phase composition, stress-strain state, and texture of the coatings have been studied in a 3D representation. It has been found that creating a state of elastic stress-strain compression in the coating can significantly enhance its resistance to oxidation upon annealing. A redistribution of elements and defects (their aligning and segregation) due to diffusion and termination of spinodal segregation has been revealed near interfaces, around grains and subgrains, which occurred without a significant change in the average size of nanograins.
We used the results of ab initio calculations to improve the high temperature mechanical properties of a Cr-Ni-base alloy (Cr-33Ni-2W-0,3Ti-0,3V, wt.%) (alloy I) with two-phase alpha - gamma ...microstructure. It was established that gamma - phase in Cr-Ni-base alloy (I) plays a key role in the processes of plastic deformation. By analogy with Ni-base superalloys the bulk and grain boundaries cohesion in gamma - phase of the Cr-Ni-base alloy (I) were strengthened by adding a package of the "low alloying" elements (Zr, Hf, Nb, Ta) (alloy II) chosen in accordance with our theoretical predictions. We further investigated an influence of a sum (Ta, Nb, Hf, Zr) like the low alloying additions on the mechanical properties of Cr-Ni-base alloy (I). The results of mechanical testing revealed a significant strengthening of the alloy (II) in comparison with (I) at the temperature 1080 oC in accordance with our predictions. We also investigated the microstructure's peculiarities of the alloys (I) and (II).
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