Certain characteristics of zirconium-containing anodic films on aluminum

Some data on zirconium-containing layers plasma-electrochemically (P-E) applied to A7 aluminum alloy (obtained by using x-ray spectral and diffraction analyses, electron microscopy, as well as measuring their thickness and visible light reflection) are discussed. The properties of the P-E applied structures formed under power-drop conditions are studied as functions of the potassium hexafluorozirconate bath temperature (20–70°C) and initial voltage (300–500 V). Original Russian Text ? K.N. Kilin, V.S. Rudnev, P.M. Nedozorov, T.P. Yarovaya, 2006, published in Zashchita Metallov, 2006, Vol. 42, No. 3, pp. 285–291.     

Hepatitis B and C virus infections in Turkish children with haemophilia

We examined 41 Turkish children with haemophilia for evidence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections using the enzyme-linked immunosorbent assay (ELISA). Hepatitis B surface antigen was found to be positive in 11 patients (26.8%) and HCV-specific antibody (anti-HCV) was detected in 10 (24.4%) patients. There was a close relationship of the number of transfusions of blood plasma to the presence of HCV specific antibody, but not to the serum markers of HBV infection. In countries where HBV infection is commonly seen and problems in transfusion practice continue, as in Turkey, children with haemophilia are at greater risk for HBV and HCV infections.     

Plasma-electrolytic oxidation of titanium in Zr(SO<Subscript>4</Subscript>)<Subscript>2</Subscript>-containing electrolyte

It is shown that anodic oxide coatings with a thickness of several to 300 νm can be obtained on titanium by varying the charge spent on (Q). The prevailing phase in the coatings is ZrO₂ in monoclinic and tetragonal modifications. The content of zirconium in the layers is up to 20 at %. Distributions of titanium, zirconium, and oxygen in the cross sections of the coatings are obtained, and the effect of Q on the formation and elementary and phase compositions of the coatings is studied. Tentative experiments clarifying the effects of bipolar anodic-cathodic polarization and electrolyte aging on the composition of coatings are carried out. The coatings are shown to be stable at temperature variations in the range of 20–700°C and to decrease the contact corrosion current at the (titanium + coating)—St3 steel interface by a digit of 10–15 in 3% NaCl.     

Plasma-electrolytic oxidation of valve metals in Zr(IV)-containing electrolytes

The studies devoted to the production of Zr-containing coatings on valve metals (Ti, Al, and Mg) using plasma-electrolytic oxidation are reviewed. The coatings are formed from aqueous electrolyte suspensions containing dispersed ZrO₂ particles, as well as Zr(IV) fluorocomplexes, polyphosphate, and tartrate complexes, and from Zr(SO₄)₂ electrolytes. The layers that contain both zirconium oxide in either monoclinic or tetragonal modification and zirconium pyrophosphate and layers containing simple and complex zirconium phosphates are obtained. The described approaches enable one to produce protective layers and can form the basis of the technique for obtaining surface structures with a complex chemical composition, as well as coatings that contain certain compounds with specific characteristics.     

Some properties and microstructure of C-TiC alloys obtained by precipitation from the gaseous phase

Conclusions It has been established that C-TiC alloys prepared by precipitation from the gaseous phase constitute mixtures of titanium carbide and pyrographite. Like pyrographite, they exhibit an anisotropy of properties, the degree of anisotropy decreasing with increasing titanium carbide content of the alloys.Translated from Poroshkovaya Metallurgiya, No. 12 (84), pp. 32–38, December, 1969.     

Hyperfine Characteristics of Quantum Registers NV-13С in Diamond Nanocrystals Formed by Seeding Approach from Isotopic Aza-Adamantane and Methyl-Aza-Adamanthane

Semiconductors - We predict the characteristics of hyperfine interactions (hfi) for a number of electron-nuclear spin systems NV-13C in diamonds grown by seeding approach from the specific isotopic...     

Using Neural Networks in Controlling Low- and Medium-Capacity Gas-Turbine Plants

The possibilities of using neural network technologies for synthesizing new and improving existent gas-turbine plant (GTP) control systems are considered. Modern gas-turbine plant control systems are often developed on the basis of aviation automatic control systems, without taking into account the peculiarities of load changes in electricity generation. As a result, frequency-related quality indicators of electricity, such as maximum deviation and recovery time, do not always meet requirements that have been set out. This study is aimed at improving the quality of generated electricity. A list of different disturbances that can arise in an electric power system is provided, as well as the results of using the neural network model of a GTP to optimize the parameters of the gas-turbine unit adjuster.     

Losses of magnetite iron in wet separation

Samples of all the tailings from enrichment processes at the Abagur plant operated by OAO Evrazruda are studied. The tailings are subjected to magnetic and chemical analysis, and the magnetic characteristics of the products are measured. The mean magnetite iron content in the tailings was about 0.9% in 2013. Experiments confirm that the main magnetite losses are associated with small classes and their poor magnetic properties. The losses of magnetite are reduced as the separation field is increased. At the plant, 45% of the barium–ferrite magnetic systems in the PBM 90/250 separators have been replaced by a system based on neodymium–iron–boron composites, with increase in the field from 111 to 175 kA/m. Modernization of the magnetic systems in all the separators at the Abagur plant is recommended. In thickening, the installation of separators for regeneration of the suspensions, with a field of 190 kA/m, is recommended. After reconstruction, the losses of magnetite iron at the plant may be reduced to 0.45–0.55%.     

Time-level relationship for lipid peroxidation and the protective effect of alpha-tocopherol in experimental mild and severe brain injury

OBJECTIVE: Oxygen free radical-mediated lipid peroxidation has been proposed to be one of the major mechanisms of secondary damage in traumatic brain injury. The first purpose of this study was to establish the time-level relationship for lipid peroxidation in injured brain tissue. The second purpose was to examine the protective effect of alpha-tocopherol against lipid peroxidation. METHODS: For this study, 65 guinea pigs in five groups were studied. Five of the animals were identified as a control group, and the remaining 60 animals were divided equally into four groups (Groups A, B, C, and D). Mild injury (200 g x cm) (Groups A and C) and severe injury (1000 g x cm) (Groups B and D) were produced by the method of Feeney et al. Alpha-tocopherol (100 mg/kg) was administered intraperitoneally before brain injury in Groups C and D. Five animals from each group were killed immediately after trauma, five after 1 hour, and the remaining five animals after 36 hours. Lipid peroxidation in traumatized brain tissues was assessed using the thiobarbituric acid method. RESULTS: In all groups with traumatic brain injuries, levels of malondialdehyde, a lipid peroxidation product, were higher than in the control group. The amount of lipid peroxidation was increased by the severity of the trauma. Alpha-tocopherol significantly suppressed the rise in lipid peroxide levels in traumatized brain tissues. CONCLUSION: This study demonstrates that lipid peroxidation is increased by the severity of trauma and that alpha-tocopherol has a protective effect against oxygen free radical-mediated lipid peroxidation in mild and severe brain injury.