Effect of heat flow on heat‐transfer characteristics for a supersonic spatial flow around a spherically blunted cone

Heattransfer processes for a supersonic spatial flow around a spherically blunted cone were studied by solving direct and inverse threedimensional problems taking into account heat flow along the longitudinal and circumferential coordinates. It is shown that highly heatconducting materials can be used to advantage to decrease the maximum temperatures on the windward side of streamline bodies.     

Heat‐and mass‐transfer characteristics in a spatial subsonic flow around a blunt body

A study was performed of methods for controlling thermal regimes in a spatial supersonic flow around a blunt body with the simultaneous use of gas injection from the surface of the porous bluntness and heat flow in the shell material. The effect of the nonisothermicity of the shell wall on the heat and masstransfer characteristics in the boundary layer was taken into account by solution of the problem in a conjugate formulation. It is shown that heat conducting materials can be used to advantage to reduce the maximum temperatures in the screen zone.     

Petrovskii elliptic systems in the extended Sobolev scale

Petrovskii elliptic systems of linear differential equations given on a closed smooth manifold are investigated in the extended Sobolev scale. This scale consists of all Hilbert spaces that are interpolation spaces with respect to the Hilbert Sobolev scale. Theorems of solvability of the elliptic systems in the extended Sobolev scale are proved. An a priori estimate for solutions is obtained, and their local regularity is studied.     

Predicting the porosity of glass-reinforced plastics from their thermal conductivity

The effect of porosity, reinforcement ratio and specific weight on the thermal conductivity of a series of glass-reinforced plastics has been investigated. It is shown that, if the thickness, the weight characteristic (weight per square meter), and the number of layers of reinforcing fabric are known and the thermal conductivities of the components are constant, then the porosity of the glass-reinforced plastic can be predicted from its thermal conductivity. Data on the relation between the specific weight and the thermal conductivity of the glass-reinforced plastics investigated are presented.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 3, pp. 522–525, May–June 1971.     

Essential Closures and AC Spectra for Reflectionless CMV,Jacobi, and Schrödinger Operators Revisited

We provide a concise, yet fairly complete discussion of the concept of essential closures of subsets of the real axis and their intimate connection with the topological support of absolutely continuous measures.As an elementary application of the notion of the essential closure of subsets of ? we revisit the fact that CMV, Jacobi, and Schrödinger operators, reflectionless on a set ? of positive Lebesgue measure, have absolutely continuous spectrum on the essential closure \({\overline{\mathcal{E}}}^{e}\) of the set ? (with uniform multiplicity two on ?). Though this result in the case of Schrödinger and Jacobi operators is known to experts, we feel it nicely illustrates the concept and usefulness of essential closures in the spectral theory of classes of reflectionless differential and difference operators.     

Physical states of aqueous solutions of oxyethylated glycerol with polymerization degree of n=30 at temperatures lower than 283 K

A binary system water-oxyethylated glycerol with polymerization degree of n=30 (OEGn=30) is studied over the concentration range of 0-100% (w/w) and the temperature range of 123-283 K by differential scanning calorimetry (DSC). A phase diagram of this system is constructed at the average cooling rate of 200 K-1 per min and the warming rate of 0.5 K-1 per min. Ice crystallization occurs and 70% (w/w) unfrozen residues remain during cooling in the OEGn=30 concentration range of 0-45% (w/w). The system hardens in the amorphous state during cooling and ice crystallization occurs during warming in the range of 46-62% (w/w). Crystallization is observed neither during the cooling nor the subsequent warming in the range of 63-74% (w/w). OEGn=30 crystallization occurs in the range of 75-100% (w/w). Each OEGn=30 molecule can strongly bind to 48 water molecules. In parallel with dsc study, the water-OEGn=30 system is investigated by cryomicroscopy in the temperature range of 173-283 K. Cryomicrographs of the solidified solutions representing each of the four concentration bands mentioned above are given.