Self-propagating high-temperature synthesis of intermetallide/oxide nanocomposite powders using mechanocomposite precursors

It was found that mechanical activation of a mixture containing iron, aluminum, and oxide iron resulted in mechanochemical reduction of iron oxide and formation of a Fe/Al/Al₂O₃ nanostructural mechanocomposite. High-temperature self-propagating synthesis (SHS) using this composite as a precursor yielded a FeAl/Al₂O₃ composite, which retained the morphology and dimensional characteristics of the precursor. During mechanical activation of a mixture of iron, aluminum, and chromium oxide, complete reduction of the latter did not occur but SHS also led to the formation of an intermetallide/oxide nanocomposite, in which chromium atoms were incorporated in the structure of iron aluminide.     

On the non-uniqueness in the dependence of the parameters of mass removal of a carbon material on the Mach number in the air flow incident on it

The non-unigueness in the dependence of the parameters of mass removal of a carbon material on the Mach number in the air flow incident on it has been established. This effect occurs in the region of fairly low values of the argument of these functions.     

Thin-film multilayer magnetic sensors based on the anisotropic magnetoresistive effect

The design and operation of thin-film multilayer sensors based on the anisotropic magnetoresistive effect are considered from the theoretical and experimental viewpoints.     

Influence of the composition of vacuum residues as oxidation feedstock on the performance characteristics of road asphalts

The hydrocarbon-group composition of short residues having different values of the specific viscosity was studied. The influence of the hydrocarbon-group composition of short residues from West Siberian crude oils on the properties of petroleum air-blown road asphalts was examined.     

Self-propagating high-temperature synthesis for immobilization of high-level waste in mineral-like ceramics: 1. Synthesis and study of titanate ceramics based on perovskite and zirconolite

Preparation of ceramics based on synthetic perovskite and zirconolite (analogs of titanate minerals) using self-propagating high-temperature synthesis (SHS) was studied. Ceramics was prepared as matrix material for immobilization of high-level waste (HLW). Using model HLW, the optimal synthetic conditions were determined which allow preparation of compact low-porosity material (in the form of cylindrical blocks) exhibiting high strength and low rate of leaching of Cs, Sr, Y, Ce, and La into double-distilled water. The phase composition and micro structure of the resulting materials were studied. As found, immobilization of Cs is accompanied by significant loss of this element.     

Vibration characteristics of a fiber-reinforced polymer bridge superstructure

Dynamic response of the first fiber-reinforced polymer composite bridge built in the US was studied using experimental modal tests and validated finite element models. This slab bridge was manufactured with a longitudinal joint, in the form of a shear-key, and was connected in the field using epoxy resins. Long-term performance of such joints is critical for future applications of similar designs. At the same time, the shear-key details are not visible, once joined, and cannot be inspected using routine inspection procedures. Hence, experimental modal analysis was used to evaluate the integrity of the longitudinal joint. A finite element model validated with field test data was developed to further study the effect of the longitudinal joint degradation on vibration characteristics of the structure. The finite element analysis was also used to evaluate the modal-based techniques for future inspections. Results indicate that the longitudinal joint is performing as intended, and only high degradation of the joint can be detected using the measured vibration characteristics of the bridge.     

Production of commutator bars for critical applications

The use of a series of progressive technical and technological measures has allowed the Kamensk-Ural’skii Nonferrous Metals Plant to significantly improve the service characteristics of commercial batches of electrical-grade semifinished bars used in key applications — commutator bars of trapezoidal cross section made of cadmium bronze BrKd1 and copper-silver alloy MS0.1. The bars are used to make commutators for electrical machinery that are subjected to large mechanical and electrical loads.     

Methods for measuring amplitudes of signals from Cherenkov counters

Measurements of the pulse heights in the T0 start trigger detector of the ALICE experiment are necessary both for time-amplitude offline correction of start signal T0 used in the time-of-flight TOF detector and for monitoring the state of the Cherenkov counters in the detector. A high amplitude resolution is not required for these tasks; what is needed is fast encoding and interfacing with the data readout system in which only time channels are available. Therefore, amplitudes are measured in the detector by pulse-height-to-time conversion using two independent methods, one of which involves quasi-logarithmic charge-to-time converter (QTC) and the other employs two—leading-edge (LED) and constant-fraction (CFD)—timing discriminators. The main characteristics of both methods and results of calibrations of the appropriate devices using a pulsed laser are presented.