Full-field stress analysis by holographic phase-stepping implementation of the photoelastic-coating method

In this paper, we describe a system for polariscopic and holographic phase-shifting implementation of the photoelastic-coating method for a full-field stress analysis. The easiest way to build the combined system is to employ a laser light source. However, coherent illumination introduces a signal-dependent speckle noise which worsens the accurate phase estimation and unwrapping. To answer the question of how it affects the phase retrieval of isochromatics, isoclinics and isopachics, we modeled in the present paper the phase-shifting photoelastic measurement in the presence of speckle noise through the calculation of the complex amplitudes in a Mach-Zender interferometer combined with a circular polariscope and made denoising of simulated and experimental fringe patterns. The latter were recorded at pure tensile load for PhotoStress (R)-coated samples with a mechanical stress concentrator

WORKING OUT OF MAIN EXEMPLARY EDUCATIONAL PROGRAMS FOR BACHELORS, MASTERS AND SPECIALISTS IN THE FIELD OF CONSTRUCTION

Introduction. The system of higher education in Russia is in the state of permanent transformation. During the recent period the aim of transformations has been adapting professional educational programs to the demands of community of professionals. The result of these transformations is approval of updated federal state educational standards, which obtained abbreviation “FSES 3++”. The essence of the standards updating is in establishing rules of accounting professional standards at development of professional educational programs. Starting from 2019 the training of personnel for construction industry will be fulfilled in compliance with FSES 3++. The training content of graduates is determined by educational organizations in compliance with exemplary main educational programs (EMEP). The article describes the experience of Federal educational methodical association in the system of higher education in an enlarged group of specialties and areas of training 08.00.00 Engineering and construction technology for development of EMEP. Materials and methods. In order to ensure the uniformity of the requirements for education of graduates of different profiles and qualifications, it was decided to develop EMEP for each of the main directions (profiles) of educational programs. As part of the development of EMEP, a methodology for formulating professional competencies based on an analysis of the requirements of professional standards was proposed and applied. Formulation of indicators of achievements in competencies was carried out in the form of a description of labour actions. Results. To date several draft EMEPs have been worked out for different directions and levels of education. A proven methodology for development of EMEP is used to compile EMEP for other areas. Conclusions. The process of harmonizing the educational and professional standards will permit not only solving the problem of professional orientation of educational programs, but also in this regard the task of ensuring quality of graduates training required by employers. For this purpose, EMEP should be developed separately according to the directions of educational programs and establish mandatory professional competencies. Such an approach to the development of EMEP also ensures the achievement of unity of the educational system as one of the requirements of the Federal Law “On Education in the Russian Federation”

Trends in development of dynamic holographic displays

Creation of a dynamic 3-D display based on holography, in which a 3-D scene is encoded in terms of optical diffraction, transformed into the fringe patterns of the hologram that is further converted into a signal for a spatial light modulator (SLM) and displayed in real time, is an extremely challenging enterprise. There are various approaches targeted to solve associated problems

Temperature dependence of electric resistance and magnetoresistance of pressed nanocomposites of multilayer nanotubes with the structure of nested cones

Bulk samples of carbon multilayer nanotubes with the structure of nested cones (fishbone structure) suitable for transport measurements, were prepared by compressing under high pressure (~25 kbar) a nanotube precursor synthesized through thermal decomposition of polyethylene catalyzed by nickel. The structure of the initial nanotube material was studied using high-resolution transmission electron microscopy. In the low-temperature range (4.2 - 100 K) the electric resistance of the samples changes according to the law ln \rho ~ (T_0/T)^{1/3}, where T_0 ~ 7 K. The measured magnetoresistance is quadratic in the magnetic field and linear in the reciprocal temperature. The measurements have been interpreted in terms of two-dimensional variable-range hopping conductivity. It is suggested that the space between the inside and outside walls of nanotubes acts as a two-dimensional conducting medium. Estimates suggest a high value of the density of electron states at the Fermi level of about 5 10^{21} eV^{-1} cm^{-3}.Comment: 8 pages, 4 figures. EM photographic images on figures 1a, 1b, 1c attached as JPG files. For correspondence mail to [email protected]