Limiting conditions of polymer combustion at reduced pressures

Combustion, Explosion, and Shock Waves -     

Chemojet Motion in Crystallization

It was found experimentally that free bodies 40 to 60 m in size come into additional motion in various gases once a topochemical reaction has begun on their surface to yield a crystalline product on the surface or in the bulk. This motion was called chemojet motion, and the body's velocity was found to depend on the crystallization rate and to what extent crystallization is localized at active sites. Comparing the observed data with the mathematical model of chemojet motion suggested that this kind of motion is intermediate between Brownian motion and jet propulsion. Chemojet motion may be either directional or chaotic. Investigating this phenomenon is expected to deepen insight into surface processes.     

Identification and resolution of conflicts during ontological integration using rules

Abstract: Integration of ontologies of information sources and consumers is an important phase in achieving web‐based interoperability. The present work describes an approach for identifying certain semantic conflicts while integrating ontologies of heterogeneous information sources. This paper is focused on the identification of homonymy and synonymy between elements in ontologies. In the present work the concepts of homonymy and synonymy are synonymous to naming conflicts and entity identifier conflicts, respectively, and partial synonymy is synonymous to schema isomorphism conflicts. The concept of the mask of interoperability is introduced for the identification of synonymy. The mask of interoperability is expressed in a declarative way as a set of rules, which can then be used for resolution of conflicts during integration of ontologies. As proof of concept, ontologies are implemented using the XML‐based ontology language Ontology Web Language (OWL), and the rules are implemented using the emerging rule language Semantic Web Rule Language (SWRL). This representation in OWL and SWRL allows the ontology to be executable, flexibly extendable and platform‐independent. The OWL facts and SWRL rules are used by the Jess and Bossam reasoning engine to identify semantic homonymy and synonymy.     

Behavior of radioaerosols formed by evaporation of 137Cs131I and 137CsOH from the metal surface in an electrostatic field

The behavior of radioaerosols formed by condensation of supersaturated ¹³⁷Cs¹³¹I and/or ¹³⁷CsOH vapor in an electrostatic field was studied. Supersaturated ¹³⁷Cs¹³¹I and/or ¹³⁷CsOH vapor was generated by evaporation of salt crystals from a metal surface heated to high temperatures owing to ohmic resistance. By applying additional potential to the aerosol generator, it is possible to control the behavior of ¹³⁷Cs¹³¹I, ¹³⁷CsOH, or ¹³⁷Cs¹³¹I + ¹³⁷CsOH aerosols in an electrostatic field.     

A semantic approach to a framework for business domain software systems

In enterprise firms, enormous amounts of electronic documents are generated by business analysts and other business domain application users. Applications that use these documents are often driven by business logic that is hard-coded together with application logic. One approach to the separation of business logic from applications is to create and maintain business and information extraction rules in an external, user-friendly format. The drawback of such an externalization is that the business rules, usually, do not have machine interpretable semantics. This situation often leads to misinterpretation of domain analysis documents, which can inhibit the productivity of computer-assisted analytical work and the effectiveness of business solutions. This paper proposes an ontology and rule-based framework for the development of business domain applications, which includes semantic processing of externalized business rules and to some extent externalization of application logic. The creation of external information extraction rules by the business analyst is a cumbersome and time consuming task. In order to overcome this problem, the framework also includes a rule learning system to semi-automate the generation of information extraction rules from source documents with the help of manual annotations. The main idea behind the work presented in this paper is to re-engineer very large enterprise information systems to adapt to Semantic Web computing techniques. The work presented in this paper is inspired by an industrial project.     

Radiation experiments with hydrogen-containing materials on the URAM-2 cryogenic irradiation facility at the IBR-2 reactor

The URAM-2 irradiation system facility at the IBR-2 reactor is described. The results of experiments performed with this facility to study the behavior of water ice, solid methane, aromatic hydrocarbons, and other materials exposed to fast neutrons and rays are presented. The rate of energy accumulation in these materials under irradiation and the amount of accumulated hydrogen and the temperature at which the hydrogen leaves the material matrices are determined. Recommendations are made for the working temperature of these materials for use in cold neutron moderators.Translated from Atomnaya Énergiya, Vol. 97, No. 3, pp. 183–189, September, 2004.     

Concept of randomness in chemistry and ambiguity in the results of chemical experiments

A general approach to the analysis of the effect of random factors on processes in physicochemical and chemical systems is proposed. A probabilistic model of a system is constructed, which is based on the principle of variability of complex systems. The simplest functions of distribution of systems with respect to the parameters of state are presented. The function of distribution of replica experiments with respect to the measurement results in the presence of uncontrollable random factors is described. Reported at the Conf. “Liquid-Phase Systems and Nonlinear Processes in Chemistry and Chemical Technology,” Ivanovo, 1999.     

Flame propagation in a closed channel with cold side walls

On the basis of complete nonsteady two-dimensional equations describing the motion of a reactive gas we have obtained a solution for the problem of flame propagation in a plane channel with cold side walls. We study in detail the process of flame quenching. The values of the critical Peclet numbers have been determined both numerically and analytically. We have ascertained the quantitative relationships governing flame propagation in the absence of quenching.Moscow. Translated from Fizika Goreniya i Vzryva, No. 2, pp. 49–58, March–April, 1991.     

Mechanism of the Vaterite-to-Calcite Phase Transition under Sonication

The vaterite-to-calcite phase transition in spheroidal vaterite particles produced by reacting aqueous Ca(NO₃)₂ and Na₂CO₃ solutions at 20 ± 1°C under 2.6-MHz sonication was studied by scanning electron microscopy and x-ray diffraction. The results are interpreted as evidence that the transformation of vaterite, a metastable phase under ordinary conditions, to calcite follows a “relay” recrystallization mechanism: vigorous ultrasonic stirring leads to energetic collisions between vaterite and calcite particles, resulting in a transition of the metastable phase to the stable one, followed by the formation of calcite aggregates consisting of 2 to 14 particles.