Shape memory effect and superelasticity in single-phase nickel titanium single crystals

On Ti-50.3%Ni and Ti-48%Ni-2%Fe (at.%) single crystals of [001], [111], [139], [123] orientations the influence of preliminary deformation of martensitic phase and aging (marforming) on shape memory effect (SME) and superelasticity (SE) has been investigated. It has been shown that marforming leads to occurrence of SE, which is absent in initial state

Plastic deformation of nitrogen-containing austenitic stainless steel single crystals with low stacking fault energy

On single crystals of austenitic stainless steel with nitrogen C$_{\rm N}$=0-0.5 wt.% the stages of stress-strain curves, work-hardening coefficient, deformation mechanism – slip and twinning, the developing of dislocation structure in dependence on crystal tensile axis orientation, test temperature, nitrogen concentration have been investigated. The type of dislocation structure (cellular or planar) and deformation mechanism (slip or twinning) have been shown to determine by the value of matrix stacking fault energy, by the level of friction forces due to solid solution hardening with nitrogen atoms and by the crystal orientation. It has been established that the contribution of mechanical twinning to the plastic deformation of steel crystal increases with nitrogen content, and in high-strength states at concentration of interstitial atoms C$\geq$0.5 wt.% mechanical twinning develops from early stages of deformation and determines work-hardening coefficient. The achievement of high level of deformation stresses due to the solid solution hardening with nitrogen atoms in combination with low values of $\gamma_0$ results in twinning in [001] orientations

The effect of aluminium on mechanical properties and deformation mechanisms of hadfield steel single crystals

On single crystals of Hadfield steel (Fe-13Mn-1.3C, Fe-13Mn-2.7Al-1.3C, wt.%) the systematical investigations of deformation mechanisms - slip and twinning, stages of plastic flow, strain hardening coefficient depending on orientation of tensile axis have been carried out by methods of optical and electron microscopy, x-ray analysis. Is has been shown that the combination of low stacking fault energy ($\gamma_{\rm{SF}}=0.03$J/m$^2$) with high concentration of carbon atoms in aluminium-free steel results in development of the mechanical twinning at room temperature in all crystal orientations. The new type of twinning with formation of extrinsic stacking fault has been found out in [001] single crystals. Experimentally it has been established that alloying with aluminium leads to increase of stacking fault energy of Hadfield steel and suppresses twinning in all orientations of crystals at preservation of high values of strain-hardening coefficients $\theta$

Nonlinear dimensionality reduction for visualizing toxicity data: Distance-based versus topology-based approaches.

Over the years, a number of dimensionality reduction techniques have been proposed and used in chemoinformatics to perform nonlinear mappings. In this study, four representatives of nonlinear dimensionality reduction methods related to two different families were analyzed: distance-based approaches (Isomap and Diffusion Maps) and topology-based approaches (Generative Topographic Mapping (GTM) and Laplacian Eigenmaps). The considered methods were applied for the visualization of three toxicity datasets by using four sets of descriptors. Two methods, GTM and Diffusion Maps, were identified as the best approaches, which thus made it impossible to prioritize a single family of the considered dimensionality reduction methods. The intrinsic dimensionality assessment of data was performed by using the Maximum Likelihood Estimation. It was observed that descriptor sets with a higher intrinsic dimensionality contributed maps of lower quality. A new statistical coefficient, which combines two previously known ones, was proposed to automatically rank the maps. Instead of relying on one of the best methods, we propose to automatically generate maps with different parameter values for different descriptor sets. By following this procedure, the maps with the highest values of the introduced statistical coefficient can be automatically selected and used as a starting point for visual inspection by the user

The shape memory effect and superelasticity in Ti-Ni single crystals with one variant of dispersed particles

On [-111] single crystals of Ti-(50.8-51) at.%Ni the aging under stress results in the formation of one variant of Ti$_3$Ni$_4$ particles, after aging without stress four variants of particles are observed. It has been shown that the values of shape memory effect and superelasticity at tension depend on the number of particle variants and their orientation relative to the tension axis. It is revealed that elastic twinning in R-phase is connected with the convertible reorientation of R martensite in field of external stress

Whole blood and hair trace elements and minerals in children living in metal-polluted area near copper smelter in Karabash, Chelyabinsk region, Russia

The primary aim of the study is assessment of hair and whole blood trace element and mineral levels in children living in a polluted area near a copper smelter (Karabash) and two control locations (Varna, Tomino) using inductively coupled plasma mass spectrometry. The obtained data indicates that both blood and hair As, Pb, and Fe levels in children living in Karabash significantly exceeded the control values. Whole blood levels of copper in children living in Varna exceeded that in Tomino (p = 0.155) and Karabash (p < 0.001) by 16 %. Oppositely, hair concentration of Cu was maximal in children from Karabash. Blood Ca and Mg content in children from Varna exceeded the respective values from Tomino and Karabash by 32 % (p = 0.021) and 42 % (p < 0.001), and 19 % (p < 0.001) and 9 % (p < 0.001), respectively. Similar differences were observed in hair mineral content. Oppositely, children living in Tomino and Karabash were characterized by 10 (p = 0.002) and 23 % (p < 0.001) higher levels of blood phosphorus. At the same time, hair P content was maximal in a polluted area. Therefore, children living in a polluted area near a copper smelter had significantly higher values of heavy metals and decreased Mg and Ca content in biosamples. It is supposed that adverse health effects in persons living near a copper smelter may be associated not only with toxic metal overexposure but also with altered mineral homeostasis. © 2016, Springer-Verlag Berlin Heidelberg

Whole blood and hair trace elements and minerals in children living in metal-polluted area near copper smelter in Karabash, Chelyabinsk region, Russia

The primary aim of the study is assessment of hair and whole blood trace element and mineral levels in children living in a polluted area near a copper smelter (Karabash) and two control locations (Varna, Tomino) using inductively coupled plasma mass spectrometry. The obtained data indicates that both blood and hair As, Pb, and Fe levels in children living in Karabash significantly exceeded the control values. Whole blood levels of copper in children living in Varna exceeded that in Tomino (p = 0.155) and Karabash (p < 0.001) by 16 %. Oppositely, hair concentration of Cu was maximal in children from Karabash. Blood Ca and Mg content in children from Varna exceeded the respective values from Tomino and Karabash by 32 % (p = 0.021) and 42 % (p < 0.001), and 19 % (p < 0.001) and 9 % (p < 0.001), respectively. Similar differences were observed in hair mineral content. Oppositely, children living in Tomino and Karabash were characterized by 10 (p = 0.002) and 23 % (p < 0.001) higher levels of blood phosphorus. At the same time, hair P content was maximal in a polluted area. Therefore, children living in a polluted area near a copper smelter had significantly higher values of heavy metals and decreased Mg and Ca content in biosamples. It is supposed that adverse health effects in persons living near a copper smelter may be associated not only with toxic metal overexposure but also with altered mineral homeostasis. © 2016, Springer-Verlag Berlin Heidelberg

The shape memory effect and superelasticity in nickel-titanium single crystals aged under applied stress

Aging under applied stress of $$and$$ Ti-51at.%Ni single crystals leads to the formation of one crystallographic variant of Ti$_3$Ni$_4$ particles, but after aging without stress four particle variants are observed. It bas been shown that the values of shape memory effect and superelasticity are dependent on the number of precipitate variants and particle sizes