Radiation hardening of constructional cement–magnetite–serpentinite composite under gamma irradiation at increased dose
It is shown that a constructional radiation-shielding composite material with high resistance to radiation-thermal loads can be obtained. The material was produced using a Portland cement mix, boroncontaining chrysotile, magnetite filler, plasticizing additives, and metal fraction by the vibro-packing method. The content of chemically bound water was at least 1.5 wt %. Exposure to high doses of gamma radiation led to formation of monocalcium ferrite CaFe2O4 with high physical and X-ray density in the cement– magnetite–serpentinite composite. Its formation resulted in radiation hardening and increased the mechanical strength of the composite up to the dose of 10 MGy. When a protective composite was exposed to γ radiation with the absorbed dose of 20 MGy, the mechanical strength of the composite was reduced by only 4– 5% compared to that of the unirradiated sample.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.