Создание и применение инструментальной керамики на основе сверхтвердых структурированных композитов

The state-of-the-art of development and improvement of superhard composites based on the cubic boron nitride have been considered. Such composites are used for equipment of cutting tools for machining of materials with high mechanical properties.Рассмотрены современные подходы к созданию и совершенствованию сверхтвердых композитов на основе кубического нитрида бора для оснащения режущих инструментов для обработки конструкционных материалов с высокими механическими свойствами

Modelling and Experimental Investigation of Cutting Temperature when Rough Turning Hardened Tool Steel with PCBN Tools

In this study the cutting tool temperature that develops during rough turning of hardened cold-work tool steel is modelled on the basis of experimental data. The data obtained from a series of thermocouples, placed on a PCBN insert, into an anvil, and into a toolholder, were used as the input for the model. An inverse problem was solved, where the heat fluxes and heat transfer coefficients were computed and where the developed temperature field was reconstructed from the experimental readings. The temperature was modelled for the case of new tools, as well as for the case of its development in the course of tool wear. The machining case involved utilization of a high-cBN content and a binderless PCBN grade, both possessing high thermal conductivity of 110 and 190 W/m K respectively. (C) 2015 The Authors. Published by Elsevier B.V

EFFECTIVENESS OF THE LOOP-MEDIATED ISOTHERMAL AMPLIFICATION WITH FLUORESCENT DETECTION IN THE DIAGNOSIS OF PARVOVIRUS ENTERITIS IN CARNIVORES

The aim of the study was to evaluate the diagnostic value of the method of loop-mediated isothermal amplification of DNA with real-time fluorescent detection (real-time LAMP, or RT-LAMP) on the model of carnivore parvoviruses. Materials and methods. Samples of feces, blood and swabs from the rectum of different species of predatory animals with parvovirus enteritis (n = 39) and healthy animals (n = 31), as well as laboratory strains of mink enteritis virus, were analyzed by RT-LAMP using SYTO-9 and SYTO-82 dyes. Real-time PCR was used as a reference method. Results. In our study, the LAMP method with real-time fluorescence detection (RT-LAMP) in the carnivore parvovirus enteritis model provides high analytical sensitivity (1.5×103 copies of DNA/ml), diagnostic sensitivity and specificity (up to 100% under optimal conditions). Comparison of the two intercalating dyes showed that the SYTO-82 dye provides a higher signal-to-background ratio (22.6 ± 2.1) than the SYTO-9 dye (6.3 ± 1.5) (p <0.0000001 ). At the same time, SYTO-9 dye at the sensitivity limit (10 copies of DNA) provides an increase in fluorescence in the reaction mixture 13 minutes earlier than for SYTO-82 (23 and 36 minutes, respectively). Conclusion. RT-LAMP is a promising method for rapid and highly sensitive «point-of-care» diagnosis of infectious diseases, as well as in conditions of livestock farms or in field conditions

Luminescent properties of Y₃Al₅O₁₂ nanograined ceramics and single crystals

The optical transmittance in the visible wavelength range, thermally stimulated luminescence and time resolved luminescence under excitation by synchrotron radiation in the exciton range of Y₃Al₅O₁₂ host were studied to characterize Y₃Al₅O₁₂ nanograined ceramics in comparison to single crystals of the same composition. The behavior of nanograined ceramics is situated close to the properties of single crystals with large content of Yai antisite defects. The observed differences in the optical and luminescent properties were interpreted as a consequence of high detectivity level of nanograined ceramics arising from its non-equilibrium character and high concentration of grain boundaries

Coherent phase transformations as a basis for production of highly textured polycrystals of boron nitride diamond-like phases

Some properties of high-textured polycrystals (HTP) are similar to the properties of single crystals. So, the materials on the base of HTP can be used instead of monocrystalline materials. Such replacement is especially actual for those crystalline materials the obtaining of which in the monocrystalline state is a problem. Cubic boron nitride (cBN) is one of such material. In present paper the method of massive HTP of cubic and wurtzitic BN obtaining is discussed. This method is based on the realization of coherent phase transformations in the CVD plates of graphite-like boron nitride under high pressures and temperaturesTranslated from Russian (Proceedings of Advanced Materials '99; Institute of Materials Science Problems, Nat. Acad. Sci. Ukraine, KievAvailable from British Library Document Supply Centre-DSC:9023.190(10101)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Rapid diagnostics of genital herpes by loop-mediated isothermal amplification method with fluorescent detection

Introduction. Due to the high clinical significance of herpesvirus diseases, the searching of fast and effective methods for their diagnosis remains relevant.The aim of the study was to evaluate the diagnostic efficiency of the loop-mediated isothermal amplification of DNA with real-time fluorescent detection (RT-LAMP) with SYTO-82 dye on a model of herpes simplex virus (HSV) infection.Materials and methods. A total of 44 urogenital swabs containing type 1 and type 2 HSV DNA and 43 swabs without HSV DNA, including 33 samples containing the DNA of cytomegalovirus, Epstein-Barr virus and herpesvirus type 6, were studied. For RT-LAMP, Bst 2.0 WarmStart DNA polymerase, SYTO-82 dye, LAMP primers were used.Results. The high efficiency of HSV DNA detection in the RT-LAMP reaction with SYTO-82 dye was shown. RT-LAMP in optimal conditions allowed to reduce reaction time for 2-3 times compared to real-time PCR (to 35 minutes). Analytical sensitivity of HSV type 1 and 2 detection in RT-LAMP was 103 copies of DNA/ml. The diagnostic sensitivity and specificity of the RT-LAMP diagnosis of HSV infection were 96% and 100%, respectively.Discussion. RT-LAMP method has a high sensitivity and specificity comparable to RTPCR, while the risk of false positive results obtaining is minimal.Conclusion. Thus, the reaction of RT-LAMP with SYTO-82 dye allows quickly, with high sensitivity and specificity to detect HSV DNA in clinical material and can be considered as a promising point-of-care testing method

HP-HT sintering, microstructure, and properties of B6O- and TiC-containing composites based on cBN

The article presents a study of the potential for the use of B6O superhard boron suboxide as a binder in composite materials with a low cBN content. Superhard B6O is characterized by higher mechanical properties than TiC widely used in commercial materials today. Composites containing 60 vol % cBN and different binder compositions that included B6O and TiC have been sintered in a toroid-type high-pressure apparatus at a pressure of 7.7 GPa in a temperature range from 1500 to 2000 A degrees C. The microstructure, phase and elemental composition of the sintered materials have been examined via electron microscopy and X-ray diffraction analysis. Mechanical properties have been analyzed via indentation techniques. The performance of the cutting tools produced from the sintered composites has been evaluated in turning hardened cold work tool steel