Influence of Thermal Treatment on Copper Extraction from Electronic Wastes

The results of studying the influence of the preliminary thermal treatment of crushed electronic waste (EW) at a temperature of 450°C on the copper extraction degree during the subsequent leaching of materials by solutions of nitric acid are presented. The waste of the electronic industry, in particular, automobile microcircuits and computer printed circuit boards, is chosen as a research object. It is experimentally determined that the percentage of the organic phase in the composition of the research object varies within the range of 20–25% of the mass of the crushed raw material. The results of thermogravimetric analysis (TGA) and X-ray fluorescence analysis (XRF) show that the maximum degree of organic removal and formation of oxide forms of metals are observed in the temperature range 400–450oC. A mathematical model of the copper leaching process from EW with nitric acid solutions is obtained. The optimum parameters for the process are found: the temperature in the system is 75°C, the duration of leaching is 150 min, and the concentration of acid is 4 M with the maximum copper extraction to the solution being 98%. A comparative analysis of leaching processes of two types of materials (after thermal treatment and without thermal treatment) was carried out. It is experimentally confirmed that, for materials after preliminary thermal treatment, more completed copper leaching from EW with nitric acid solutions of lower concentration is provided when compared to the leaching of raw materials without thermal treatment. It is proved that, due to the preliminary thermal treatment of the materials, phase changes occur in the composition of the research object, namely, the transition of metals to their oxide forms, which positively affects the degree of copper extraction from EW at the subsequent nitric acid leaching.     

Phase transformations and properties of the Ni-Mn-In Heusler alloy

The phase and magnetic transformations in a ferromagnetic alloy of the Ni-Mn-In system are studied using dilatometry, magnetometry, metallography, and scanning electron microscopy. The effect of a magnetic field of varying intensity on the martensitic transformation and magnetic transitions of the Ni₄₇Mn₄₂In₁₁ alloy is found. It is shown that the linear expansion coefficient and magnetization exhibit an anomalous behavior in the region of the magnetostructural transition.     

Hydrogenation of Zr3Al2 in hydrogen and ammonia

We have identified conditions for the formation of Zr₃Al₂-based intermetallic hydrides through reactions with hydrogen and ammonia at temperatures from 150 to 300°C. The use of ammonia is shown to reduce the onset temperature for the formation of a hydride phase by 100°C compared to hydrogenation with hydrogen. Increasing the ammonia-Zr₃Al₂ reaction temperature to 500°C in the presence of NH₄Cl as an activator leads to the decomposition of the intermetallic compound and the formation of finely dispersed zirconium hydride and zirconium nitride powders.     

Origin of the monochromatic photoemission peak in diamondoid monolayers

Recent photoemission experiments have discovered a highly monochromatized secondary electron peak emitted from diamondoid self-assembled monolayers on metal substrates. New experimental data and simulation results are presented to show that a combination of negative electron affinity and strong electron-phonon scattering is responsible for this behavior. The simulation results are generated using a simple Monte Carlo transport algorithm. The simulated spectra recreate the main spectral features of the measured ones.     

Martensitic and magnetic transformations in Ni-Mn-In alloys

Dilatometry, magnetometry, and optical metallography were used to study structural and magnetic transformations in Ni-Mn-In alloys of different compositions. Temperatures of structural and magnetic transformations of the Ni_{47 − x} Mn_{42 + x} In₁₁ alloys (with x = 0–2) were determined. It is shown that, as the valence electron concentration decreases, the martensitic transformation temperature decreases. Some of the Ni-Mn-In alloys exhibit a ferromagnetic transformation in both the initial austenite and in the arising martensite.     

Temperature hysteresis of AgI phase transition in AgI–chalcogenide glass nanolayered films

Using a method of laser ablation, a number of AgI–chalcogenide glass nanolayered films has been obtained with different thicknesses of the layers (10, 25, 50, and 100 nm). In order to study α ? β phase transition in AgI, X-ray phase analysis has been carried out in the temperature range from 30 to 200°C. A correlation between the layer thickness and the temperature of the α → β phase transition during the lowering of the temperature is found. An explanation of the correlation is proposed.     

On the role of retained austenite in the structure of alloyed steels and the effect of external factors

We present a review of the results of the effect of external factors on the amount of austenite retained in steels and alloys. Possible methods of reducing the amount of retained austenite via the action of cold treatment, magnetic field, and plastic deformation, as well as the question of the effect of retained austenite on the mechanical properties of commercial and model steels and alloys, — have been discussed and analyzed.     

C-cell hyperplasia and medullary thyroid carcinoma in patients routinely screened for serum calcitonin

To elucidate the differential reactivity of pulmonary microvessels in the acini to hypoxia, excessive CO2, and increased H+, we investigated changes in the diameter of precapillary arterioles, postcapillary venules, and capillaries in isolated rat lungs on exposure to normocapnic hypoxia (2% O2), normoxic hypercapnia (15% CO2), and isocapnic acidosis (0.01 mol/L HCl). Microvascular diameters were precisely examined using a real-time confocal laser scanning luminescence microscope coupled to a high-sensitivity camera with an image intensifier. Measurements were made under conditions with and without indomethacin or N(omega)-nitro-L-arginine methyl ester to assess the importance of vasoactive substances produced by cyclooxygenase (COX) or NO synthase (NOS) as it relates to the reactivity of pulmonary microvessels to physiological stimuli. We found that acute hypoxia contracted precapillary arterioles that had diameters of 20 to 30 microm but did not constrict postcapillary venules of similar size. COX- and NOS-related vasoactive substances did not modulate hypoxia-elicited arteriolar constriction. Hypercapnia induced a distinct venular dilatation closely associated with vasodilators produced by COX but not by NOS. Arterioles were appreciably constricted in isocapnic acidosis when NOS, but not COX, was suppressed, whereas venules showed no constrictive response even when both enzymes were inhibited. Capillaries were neither constricted nor dilated under any experimental conditions. These findings suggest that reactivity to hypoxia, CO2, and H+ is not qualitatively similar among intra-acinar microvessels, in which COX- and NOS-associated vasoactive substances function differently.     

The importance of studies of the glycosaminoglycans in the peripheral blood leukocytes of patients in the diagnosis of the phases of chronic myeloleukemia]

To elucidate new diagnostic markers of chronic myeloid leukemia (CML) phases, we investigated quantitative and qualitative composition of glycosaminoglycans (GAG) of leukocytes from peripheral blood of 72 patients. Chronic CML phase was characterized by elevated GAG levels (2 times compared to normal values), weakening of anionic properties of chondroitin sulfate (CS) and high amount of heparan sulfate (HS). In CML transformation in the progressive phase overall concentration of GAG grew still higher, GAG fraction composition changed. In the blast crisis there was a sharp fall in the overall GAG, new electrophoretic fractions emerged. In the myeloid variant of the crisis an additional GAG component appeared (GAG-m), whereas in the lymphoid variant another component was found (GAG-1). It is suggested that the number and composition of GAG in peripheral blood leukocytes may serve markers of CML phase.