Internal Stresses, Corrosion and Electrochemical Behavior in Soils, and Stress Corrosion of Pipe Steels

The results of field tests carried out at main gas pipelines (MP) are shown. The distribution of internal stresses along the MP perimeter is obtained. Polarization currents at differently strained pipeline fragments are determined in soils taken at different distances from the failure epicenter. The mechanoelectrochemical effect is shown to be twice greater in failure soils. Its value can serve as a criterion of the stress corrosion probability.     

Analysis of instantaneous cardiac rhythm in a model of multifractal dynamics based on Holter monitoring

For the specific analysis of the variability of RR intervals of the cardiac rhythm, a method for measuring the instantaneous cardiac rhythm (ICR) represented by a multifractal dynamical model (MDM) has been developed. The advantages of this method, compared to the statistical methods of analysis of the RR intervals used, have been demonstrated. The method allows possible catastrophes of the cardiovascular system to be predicted. Using the data of Holter monitoring and the program system developed, we have plotted ICR curves, an ICR piecewise linear trend, and variability charts for three randomly chosen time intervals. The self-similarity (fractality) of the ICR up to an accuracy of 5% has been shown based on the explicit data. The MDM parameters have been calculated based on the ICR data. The analysis of the dynamics of these parameters has been conducted and their compliance with the status of the patient examined has been studied. The relevance of the ICR examination within MDM is closely related to the necessity of recognizing new markers of adverse cardiovascular episodes. The research performed shows that the results obtained could be taken as a basis for developing a new mathematical method of ICR examination based on Holter monitoring.     

Perceived interactivity leading to e-loyalty: Development of a model for cognitive–affective user responses

Novel applications of website interactivity are important to attract and retain online users. In this empirical study five designs for interactivity are examined using different web-poll interfaces. The goal of the investigation is to examine perceived interactivity in a model which includes most commonly tested cognitive elements such as efficiency and effectiveness, but augments this model with the inclusion of a cognitive–affective element for trust, and an affective element of enjoyment. More specifically, a model is created to validate the relationship of perceived interactivity (comprised of user control, user connectedness, and responsiveness of the web-poll application) to efficiency, effectiveness, trust and enjoyment, of the website. In turn, efficiency, effectiveness, trust, and enjoyment are tested for their influence on user behavioral intentions for e-loyalty. All relationships in the model are supported. In addition, exploratory evaluation of qualitative comments is conducted to investigate additional insights between the five web-poll treatments in this investigation. The research confirms the complexity of a model in which cognitive, cognitive–affective and affective elements are present, and advances knowledge on the consequences of perceived interactivity. In additional to theoretical advancements, the research has merit for web designers and online marketers regarding how to enhance interactive online web applications.     

Accounting of heterogeneity in the estimation of radiation risks

The problem is considered of taking account of heterogeneity in the individual radiosensitivity in evaluating the radiation risk of the origin of a disease in a group of persons subjected to the radiation action. Mathematical models are described for the estimation of the radiation risk of the origin of the disease with and without regard for heterogeneity. The use of the described method is demonstrated with an example of the estimation of the risk of the origin of radiation-induced diseases from the class of “solid cancers” among the persons taking part in the liquidation of consequences of the accident at the Chernobyl’ Atomic Power Station (CAPS) in the years 1986–1991. It is shown that the heterogeneity disregard leads to understated estimates of the radiation risk of the origin of radiation-induced solid cancers. The effect is investigated of the length of the latent period in the origin of radiation-induced “solid cancers” in taking account of heterogeneity.     

Radioactive contamination of the environment with241Am as a result of the chernobyl accident

All Union Scientific-Research Institute of Nuclear Power Plants. Industrial Association "Chernobyk'skaya Atomnaya élektrostantsiya," Ukraine. Translated from Atomnaya énergiya, Vol. 77, No. 2, pp. 140–145, August, 1994.     

Technical diagnostics in accident risk assessment

For a comprehensive assessment of safety of hazardous facilities, an accident risk ratio is used. Existing methodologies of risk assessment do not account for technical conditions of the facility and the degree of its defectiveness. This work demonstrates the possibility and necessity of a broader use of nondestructive testing (NDT) and technical diagnostics (TD) to estimate the probability of an accident, formulates the requirements for analyzing the risk, and establishes the line of development for these approaches. We consider the issues related to introducing new requirements for NDT and TD, which deal with representing the quantitative values of NDT, i.e., reliable data on the size of defects and measurement errors. We prove the necessity of using the methods of probabilistic fracture mechanics for assessing the real values of accident probability.     

The Effect of Charge Transport Mechanisms on the Efficiency of Al<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Ga<Subscript>1 – <Emphasis Type="Italic">x</Emphasis></Subscript>As/GaAs Photodiodes

Photovoltaic characteristics of heterostructure Al_xGa_{1 – x}As/GaAs p–i–n photodiodes fabricated by molecular-beam epitaxy have been studied. Efficiencies of 50% were reached in conversion of monochromatic light in the photovoltaic mode at power density of up to 200 W/cm² at a wavelength λ = 830 nm. A relationship was demonstrated between the “saturation currents” for the diffusion-related charge-transport mechanism (Shockley) in p–i–n photodiodes, calculated from dark current–voltage characteristics, and the experimental values of efficiency. As the “saturation current” of the diffusion-related charge-transport mechanism increases by an order of magnitude, a relative decrease in the efficiency from the maximum value by more than 10% is observed under excitation by constant or pulsed monochromatic light.     

Polarization holographic gratings in side-chain azobenzene polyesters with linear and circular photoanisotropy

We investigate thin phase polarization holographic gratings recorded with two waves with orthogonal linear polarizations in materials in which illumination with linearly/circularly polarized light gives rise to linear/circular birefringence. The theoretical analysis shows that the presence of circular photoanisot-ropy changes significantly the diffraction characteristics of the gratings. The intensities of the waves diffracted in the +1 and -1 orders of diffraction and their ratio depend substantially on the reconstructing-wave polarization. Experiments with films of side-chain liquid-crystalline azobenzene polyester that is a photoanisotropic material of the considered type confirm the unusual polarization properties. It is shown that polarization holography may be used for real-time simultaneous measurement of photoinduced linear and circular birefringence.     

Anomalies of Physical Properties inα-Bi2O3 — a Phase Transition Governed by the Electronic Mechanism?

A number of physical properties of -Bi₂O₃ was studied: the thermal expansion, thermally stimulated conductivity, electrical resistivity, and dielectric permeability. X-ray diffraction, DTA, and differential scanning calorimetry measurements were also carried out. Several anomalies were observed: a small maximum and drastic rise of the single crystal dielectric permeability, a sharp drop of the electric resistivity, a jump and change in sign of the thermally stimulated current, and an exothermal maximum in differential heat capacity. At the same time, the monoclinic lattice symmetry of -Bi₂O₃ was retained over the temperature range where these anomalies were found.     

Developing a software system for automata-based code generation

This paper is devoted to the development of the State Machine Generator system meant for automatic code generation based on the principles of automata-based programming. This system models program logic in terms of the finite-state automaton transition graph and generates program code on its basis. Basic functions of the developed software system and the mechanism of their implementation are described. This paper also proposes a new pattern for designing automaton programs. As an example, State Machine Generator is used to develop a bug tracker system for software testing.