The Mechanism and Parameters of Froth Flotation Stimulation for Diamond-Bearing Materials by Thermal and Electrochemical Effects

Journal of Mining Science - The thermodynamic analysis and tests of minerogenesis under higher temperatures determine conditions of thermochemical decomposition of hydrophilic attachments on...     

Tritium-Probe Method in a Study of Adsorption Layers of Lysozyme on the Surface of Detonation Nanodiamonds

Radiochemistry - Tritium-labeled lysozyme was used to determine its adsorption on the surface of nanodiamonds produced by detonation synthesis. It was found that the amount of the adsorbed protein...     

Polymer films as indicator of hydrogen spillover through the gas phase

Films of poly-ε-caproamide (PA), polyethylene (PE), and polyethylene terephthalate (PET) were used for detection of hydrogen spillover through the gas phase. The hydrogen used in the experiments contained tritium activated by two procedures (W wire, 2000 K; 5% Pd/C, 335 K). The radioactivity of the films was recorded by classical and digital autoradiography and by liquid scintillation counting. Under the action of “hot” atoms generated on a W wire, the maximal specific radioactivity of the films, equal to 420, 415, and 330 mCi cm^–2 for PA, PE, and PET, respectively, was reached in 100 s. Preliminary thermalization of the atoms to a temperature of 77–335 K influenced the decrease in the film radioactivity differently. The effective activation energy of the reaction in the range 298–318 K was 21, 30, and 12.5 kJ mol–1 for PA. PE, and PET, respectively. Under the conditions of heating 5% Pd/C to 335 K for 25 min, the radioactivity of PA, PE, and PET was 1.6, 0.05, and 0.15 μCi cm^–2, respectively. The revealed difference in the radioactivity of the films suggests different mechanisms of the interaction of tritium with organic molecules at different activation methods.     

Anhysteretic magnetization reversal of spin valves with a strong and weak interlayer coupling

The hysteresis of magnetoresistance has been studied as a function of the angle between the magnetic field applied in the plane of layers and the easy axis for spin valves with the composition [Ta, (Ni₈₀Fe₂₀)₆₀Cr₄₀] /Ni₈₀Fe₂₀/Co₉₀Fe₁₀/Cu/Co₉₀Fe₁₀/Mn₇₅Ir₂₅/Ta. In spin valves with a strong interlayer coupling at a small deviation of the magnetic-field direction from the easy axis there was revealed a sharp (to a few tenths of an oersted) narrowing of the hysteresis loop of the magnetization reversal of the free layer. Based on an analysis of the angular dependences of the hysteresis, critical angles at which a change occurs in the mode of the magnetization reversal have been determined. In terms of the Stoner-Wohlfarth model of the coherent rotation of the magnetization, the angles at which a transition to an anhysteretic magnetization reversal is observed have been estimated theoretically for the spin valves with a strong interlayer coupling.     

Calibrating the Prototype Calorimeter for the GAMMA-400 γ-Ray Telescope on the Positron Beam at the Pakhra Accelerator

Instruments and Experimental Techniques - A prototype of the electromagnetic calorimeter for the GAMMA-400 γ-ray telescope has been calibrated at the Pakhra S-25R electron synchrotron of the...     

Method of extending the service life of fire-extinguishing powders

This article presents results from experimental studies performed to determine the fire-extinguishing properties of powder-based compositions with a depleted storage life and finely dispersed wastes from metallurgical production operations. The data that were obtained show that it is possible to extend the service life of a fire-extinguishing powder.     

MASHA separator on the heavy ion beam for determining masses and nuclear physical properties of isotopes of heavy and superheavy elements

The MASHA mass spectrometer designed for identifying superheavy elements by their masses is described. The separation efficiency has been measured in the autonomous mode using four calibrated leakages of noble gases. The total separation efficiency of the mass spectrometer with a hot catcher and an ion source based on the electron cyclotron resonance has been determined using the ⁴⁰Ar beam. Test experiments have been carried out, in which α-active Hg isotopes produced in complete fusion reaction ⁴⁰Ar + ¹⁴⁴Sm → ^{184 ? xn} Hg + xn, have been detected in the focal plane of the mass spectrometer. The separation time and efficiency have been determined for short-lived Hg isotopes.     

A New Version of the Scintillation Phase Procedure

The scintillation phase procedure based on measuring the counting rate of compounds labeled with tritium in a two-layer scintillation cocktail-aqueous solution system was modified. Previously this procedure was used primarily for studying sorption of proteins at the phase boundary. After certain modification, it became applicable to studying the kinetics of sorption and the equilibrium sorption of various compounds at the organic scintillation cocktail-aqueous solution boundary and to evaluating the distribution coefficients of compounds in this system. Two experimental modes are proposed: common two-layer system and drop system. The suitability of these procedures for determining the surface activity and hydrophobicity of organic compounds and for studying the permeability of the molecular layers adsorbed at the phase boundary is discussed.