Fracture toughness in some hetero-modulus composite carbides: carbon inclusions and voids. Advances in Applied Ceramics

Fracture toughness of ceramics in some cases can be significantly improved by the inclusion of low-modulus phase and even voids. Structure and mechanical characteristics of dense ceramic composites synthesised by reactive hot pressing of TiC-B4C powder mixtures at 1800 - 1950°С under 30MPa during 16 minutes are investigated. X-Ray Diffraction, Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy (SEM and EDX) have shown that during hot pressing solid phase chemical interaction 2TiС + B4C = 2TiВ2 + 3С has occurred resulting in TiB2-TiC-C, TiB2-C or TiB2-B4C-C hetero-modulus composite formation with approximately 1μm carbon precipitates. The volume of such precipitated carbon can reach 35 vol. %. The fracture toughness depends on the precipitate size and amount of graphite precipitation and has a distinct maximum K1C = 10MPa∙m1/2 at nearly 7 vol. % . Such fracture toughness behaviour is explained by the proposed model of crack propagation and the model-based assessment of hetero-modulus ceramic fracture toughness. It is shown that voids and low modulus carbon inclusions blunt the cracks and can increase ceramic toughness. The later has been demonstrated in the another carbon containing ceramic Cr2AlC, so named MAX phase material, when thin film fracture resistance increases as the ceramic was deposited to be porous

CREATION OF AN ACTIVE ELEMENT OF A NEW BRANCH OF KNOWLEDGE ECONOMY – THE DIGITAL ECONOMY

The brief analysis of the development of L. V. Kantorovich's ideas in the works of his students and followers has been presented. This intellectual base can be used in solving the problems of digital transformation, digitalization, creation of digital platforms and their ecosystems in the digital economy. It has been proposed to create an active element of a new branch of knowledge economy – the digital economy – in the form of “Association of departments of applied mathematics of economic and managerial profiles of Russian Universities”, the advisability of this decision has been substantiated. The Association will allow you to simultaneously conduct research on a wide range of topical issues of the digital economy, optimally form creative teams and expert groups, carry out constant scientific communication in real time, and connect talented young people to research between the postgraduate students, graduate students, and students. Working together in the structure of the Association, the departments of higher education institutions will be able to show the effect of synergy and achieve much more results in their activities. The Association has a great educational potential, which can be effectively used to improve the various levels of personnel potential of management systems. Creating associations in the field of breakthrough technologies is the best way to activate Russia's intellectual potential

Recombinant small heat shock protein from Acholeplasma laidlawii increases the Escherichia coli viability in thermal stress by selective protein rescue

© 2017, Pleiades Publishing, Inc.In both prokaryotes and eukaryotes, the survival at temperatures considerably exceeding the optimum is supported by intense synthesis of the so-called heat shock proteins (HSPs), which act to overcome the adverse effects of heat stress. Among mycoplasmas (class Mollicutes), which have significantly reduced genomes, only some members of the Acholeplasmataceae family possess small HSPs of the α-crystallin type. Overproduction of a recombinant HSP IbpA (Hsp20) from the free-living mycoplasma Acholeplasma laidlawii was shown to increase the resistance of Escherichia coli to short-term heat shock. It has been long assumed that IbpA prevents protein aggregation and precipitation thereby increasing viability of E. coli cells. Several potential target proteins interacting with IbpA under heat stress were identified, including biosynthetic enzymes, enzymes of energy metabolism, and components of the protein synthesis machinery. Statistical analysis of physicochemical properties indicated that IbpA interaction partners significantly differ in molecular weight, charge, and isoelectric point from other members of the E. coli proteome. Upon shortterm exposure to increased temperature, IbpA was found to preferentially interact with high-molecularweight proteins having a pI of about 5.1, significantly lower than the typical values of E. coli proteins

Sanitary protection of the territory of Russian Federation. Report 2. The differentiation of the territory of a region of Russian Federation for risk of diseases dangerous for people

The risk of emergency situations in the sphere of sanitary-epidemiological welfare associated with diseases dangerous for population varies for different municipalities of a region of Russian Federation. Therefore a differentiation of a region for three types of territories (A, B, C) is necessary. Adequate number of sanitary protection measures is determined for each type of territories. The purpose of this study was the development of methodical reception for differentiation of a region of Russian Federation. Point scoping of criteria of external and. internal epidemiological risks for each of municipality is proposed as this method. Criteria of external epidemiological risk allow to take into account the probability of the importation of infectious diseases, requiring measures for sanitary protection of the territory. Criteria of internal epidemiological risk reflect both actual and. potential dangers: morbidity, the registration of particular nosologic forms of diseases in animals and. detection of pathogens in the living and. non-living environment objects. Assessment of internal risk is carried out in the analysis of information about epizootic and. epidemiological situation of infectious diseases, the list of which is proposed, with, consideration of their epidemiological significance and. can be used for any Russian Federation region. According to the results of total assessment of risks for each of municipalities the complex index of epidemiological risk (CIER) is determined. On the basis of CIER the territory type (A, B, C) is determined. Type A, B or C defines for the municipality the volume of measures for sanitary protection of the territory on the basis of a sufficient level for preparedness of forces and means of public health institutions. The method, based, on the assessment of external and. internal epidemiological risks, that allows to differentiate the region of Russian Federation, at municipal level for risk of diseases dangerous for people, is proposed, as the result of this work. A new methodical approach, will contribute to the increase of the preparedness of public health, institutions to emergency situations in the sphere of sanitary-epidemiological welfare associated, with, diseases dangerous for people

First observation of a narrow charm-strange meson DsJ(2632) -> Ds eta and D0 K+

We report the first observation of a charm-strange meson DsJ(2632) at a mass of 2632.6+/-1.6 MeV/c^2 in data from SELEX, the charm hadro-production experiment E781 at Fermilab. This state is seen in two decay modes, Ds eta and D0 K+. In the Ds eta decay mode we observe an excess of 49.3 events with a significance of 7.2sigma at a mass of 2635.9+/-2.9 MeV/c^2. There is a corresponding peak of 14 events with a significance of 5.3sigma at 2631.5+/-1.9 MeV/c^2 in the decay mode D0 K+. The decay width of this state is <17 MeV/c^2 at 90% confidence level. The relative branching ratio Gamma(D0K+)/Gamma(Dseta) is 0.16+/-0.06. The mechanism which keeps this state narrow is unclear. Its decay pattern is also unusual, being dominated by the Ds eta decay mode.Comment: 5 pages, 3 included eps figures. v2 as accepted for publication by PR

First Measurement of pi e -> pi e gamma Pion Virtual Compton Scattering

Pion Virtual Compton Scattering (VCS) via the reaction pi e --> pi e gamma was observed in the Fermilab E781 SELEX experiment. SELEX used a 600 GeV/c pi- beam incident on target atomic electrons, detecting the incident pi- and the final state pi-, electron and gamma. Theoretical predictions based on chiral perturbation theory are incorporated into a Monte Carlo simulation of the experiment and are compared to the data. The number of reconstructed events (9) and their distribution with respect to the kinematic variables (for the kinematic region studied) are in reasonable accord with the predictions. The corresponding pi- VCS experimental cross section is sigma=38.8+-13 nb, in agreement with the theoretical expectation sigma=34.7 nb.Comment: 10 pages, 12 figures, 4 tables, 25 references, SELEX home page is http://fn781a.fnal.gov/, revised July 21, 2002 in response to journal referee Comment

First Observation of the Doubly Charmed Baryon Xi_cc^+

We observe a signal for the doubly charmed baryon Xi_cc^+ in the charged decay mode Xi_cc^+ --> Lambda_c^+ K- pi+ in data from SELEX, the charm hadro-production experiment at Fermilab. We observe an excess of 15.9 events over an expected background of 6.1 +/- 0.5 events, a statistical significance of 6.3sigma. The observed mass of this state is (3519 +/- 1) MeV/c^2. The Gaussian mass width of this state is 3MeV/c^2, consistent with resolution; its lifetime is less than 33fsec at 90% confidence.Comment: 5 pages, 3 figures, accepted for publication in Physical Review Letter

Observation of the Cabibbo-suppressed decay Xi_c+ -> p K- pi+

We report the first observation of the Cabibbo-suppressed charm baryon decay Xi_c+ -> p K- pi+. We observe 150 +- 22 events for the signal. The data were accumulated using the SELEX spectrometer during the 1996-1997 fixed target run at Fermilab, chiefly from a 600 GeV/c Sigma- beam. The branching fractions of the decay relative to the Cabibbo-favored Xi_c+ -> Sigma+ K- pi+ and Xi_c+ -> X- pi+ pi+ are measured to be B(Xi_c+ -> p K- pi+)/B(Xi_c+ -> Sigma+ K- pi+) = 0.22 +- 0.06 +- 0.03 and B(Xi_c+ -> p K- pi+)/B(Xi_c+ -> X- pi+ pi+) = 0.20 +- 0.04 +- 0.02, respectively.Comment: 5 pages, RevTeX, 3 figures (postscript), Submitted to Phys. Rev. Let

АНАЛИЗ МНЕНИЯ БОЛЬНЫХ О КАЧЕСТВЕ СТАЦИОНАРНОЙ ПОМОЩИ В ОТДЕЛЕНИЯХ КАРДИОЛОГИЧЕСКОГО ПРОФИЛЯ С РАЗНОЙ ИНТЕНСИВНОСТЬЮ УХОДА И ЛЕЧЕНИЯ

The article presents the analysis of the results of sociological studies of the patients admitted to cardiac unit for patients with myocardial infarction and to the Department of medical rehabilitation for such patients. We studied the influence of ethical aspects of conduct of the medical staff, and household conditions in the offices on the level of patients' satisfaction with quality of medical care.Представлен анализ результатов социологического исследования пациентов, госпитализированных в кардиологическое отделение для больных инфарктом миокарда и в отделение медицинской реабилитации для таких больных. Изучено влияние деонтологических аспектов поведения медицинского персонала и бытовых условий пребывания в отделениях на уровень удовлетворенности пациентов качеством медицинской помощи