Plasticity of materials determined by the indentation method

In this review, the development of techniques for determining the plasticity of mate rials by the indentation is considered.У даному огляді розглянуто розвиток метод визначення пластичности матеріялів індентуванням.В данном обзоре рассмотрено развитие методик определения пластичности материалов индентированием

Beam spin asymmetry measurements of deeply virtual π0 production with CLAS12

The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive pi0 production in a wide kinematic region with the photon virtualities Q2 up to 6.6 GeV2 and the Bjorken scaling variable xB in the valence regime. The data were collected by the CEBAF Large Acceptance Spectrometer (CLAS12) at Jefferson Lab with longitudinally polarized 10.6 GeV electrons scattered on an unpolarized liquid-hydrogen target. Sizable asymmetry values indicate a substantial contribution from transverse virtual photon amplitudes to the polarized structure functions. The interpretation of these measurements in terms of the Generalized Parton Distributions (GPDs) demonstrates their sensitivity to the chiral-odd GPD ET, which contains information on quark transverse spin densities in unpolarized and polarized nucleons and provides access to the nucleon's transverse anomalous magnetic moment. Additionally, the data were compared to a theoretical model based on a Regge formalism that was extended to the high photon virtualities

Construction of stess-strain curves for brittle materials by indentation in a wide temperature range

A test method procedure for constructing stress-strain curves by indentation of brittle and low plastic materials under temperature ranging from 20 to 900°C was developed recently by Yu. Milman, B. Galanov et al. According to this test method procedure stress-strain curves σ - Є for Si, Ge, SiC, TiB2 and WC/Co hard alloy were constructed in the above temperature region and mechanical parameters such as elastic point, σe, yield stress, σs, etc. were extracted by using the measurement results obtained by a set of trihedral pyramid indenters with different angles at the tip, γ1, ranging from 45 to 85°C

Approaches to the surgical treatment of congenital clubfoot in children

Background. The clubfoot is a severe deformity of the foot. The birth rate of children with congenital clubfoot is 0.1–0.4 %. Since the end of the 1980s, when the technique of I. Ponseti gained worldwide recognition, early conservative treatment using staged plaster casts has been the main feature. The effectiveness of this technique reaches 93 % and can significantly reduce the number of surgical interventions. However, delayed treatment, the absence or non-compliance with the mode of wearing braces, concomitant neurological pathology lead to a decrease in the effectiveness of conservative treatment and the use of surgery. The objective of the study is a retrospective analysis of the results of applying our surgical method for congenital clubfoot in children. Materials and methods. From 2009 to 2017, 87 children (57 boys (78 feet) and 30 girls (37 feet)) with congenital clubfoot were treated surgically in the orthopaedics and trauma unit of National Children Specialized Hospital “OHMATDYT”. During the study, we have taken into account the age, sex, type of deformity, volume of surgical intervention, immediate results of surgical treatment (up to 1 year), frequency of relapses. Sixty seven patients (83 feet) were operated for the first time, and in 20 children (32 feet), surgical treatment was repeated. The average age of patients was 4.5 years. Results. The immediate results of treatment (1 year after the operation) were good in 65 patients (74.7 %), satisfactory — in 14 (16 %) and unsatisfactory — in 8 (9.3 %). Two (2.3 %) patients had elements of excessive correction of deformity, which was manifested by pronation with valgus deformity of the heel. Relapses manifested by the appearance of one of deformity elements were detected in 8 (9.2 %) cases. The main their causes were non-compliance with the recommendations at the stages of rehabilitation (6 patients) and postoperative complications (2 patients). Conclusions. Immediate results of treatment (1 year after surgery) indicate the correctness of our approach for surgical reconstruction of the foot in patients with clubfoot

CVD niobium in Nb-Hal-(H)-inert gas systems : A thermodynamic and experimental approaches

The thermodynamic analysis of the niobium CVD in Nb-Hal-(H)-inert gas (Hal = l, Cl) systems has been performed with using the method of minimization of the Gibbs' free energy for the wide region of conditions. The results of the thermodynamic calculations allow to select the Nb-I-inert gas system as the more preferable hydrogen free system. The experimental niobium CVD data in the Nb-Cl-H-inert gas system were analyzed with thermodynamic view. The calculations and experimental results show a good agreement

Alignment of the CLAS12 central hybrid tracker with a Kalman Filter

International audienceSeveral factors can contribute to the difficulty of aligning the sensors of tracking detectors, including a large number of modules, multiple types of detector technologies, and non-linear strip patterns on the sensors. The latter two of these three factors apply to the CLAS12 CVT, which is a hybrid detector consisting of planar silicon sensors with non-parallel strips, and cylindrical micromegas sensors with longitudinal and arc-shaped strips located within a 5 T superconducting solenoid. To align this detector, we used the Kalman Alignment Algorithm, which accounts for correlations between the alignment parameters without requiring the time-consuming inversion of large matrices. This is the first time that this algorithm has been adapted for use with hybrid technologies, non-parallel strips, and curved sensors. We present the results for the first alignment of the CLAS12 CVT using straight tracks from cosmic rays and from a target with the magnetic field turned off. After running this procedure, we achieved alignment at the level of l. 967 10μm, and the widths of the residual spectra were greatly reduced. These results attest to the flexibility of this algorithm and its applicability to future use in the CLAS12 CVT and other hybrid or curved trackers, such as those proposed for the future Electron-Ion Collider

Observation of Beam Spin Asymmetries in the Process ep→e′π+π−Xep\rightarrow{e}^{'}{\pi}^{+}{\pi}^{-}X with CLAS12

International audienceThe observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first opportunity to extract the parton distribution function e(x), which provides information about the interaction between gluons and quarks, in a collinear framework that offers cleaner access than previous measurements. The asymmetries also constitute the first ever signal sensitive to the helicity-dependent two-pion fragmentation function G1⊥. A clear sign change is observed around the ρ mass that appears in model calculations and is indicative of the dependence of the produced pions on the helicity of the fragmenting quark