Ufa State Aviation Technical University (USATU) (Russian: Уфимский Государственный Авиационный Технический Университет, Bashkir: Өфө дәүләт авиация техник университеты, ӨДАТУ) is a state higher school, located in Ufa, Bashkortostan, Russia. Ufa State Aviation Technical University was founded in 1932 in Rybinsk, USSR (moved to Ufa during WWII). Nowadays, Ufa State Aviation Technical University has become the one of leading higher educational institutions of Russia and represents a large scientific and educational complex. There are 18 areas of study and 40 programs in its 7 faculties (full-time and by correspondence).More than 20,000 students study at the university.
The characteristics of aviation kerosene pulsed jets atomization formed by a high-pressure air-assisted injection system are investigated. A configuration with a high-pressure channel elongated to 500 mm is being considered, which is determined by the design requirements. The influence of the elongated channel on the dispersed composition and the cycle-to-cycle variability of the characteristics of pulsed jets is analyzed. It is shown that the air-assisted injection system provides the high-quality spraying with acceptable cycle-to-cycle variability.
Для решения уравнения Стокса развивается новый подход, основанный на его интерпретации как задачи оптимального управления. Получена итерационная процедура решения рассматриваемой задачи на основе метода итеративной регуляризации, при этом явно находятся параметры итерационного процесса и, используя специфику минимизируемого функционала, удается ускорить сходимость процесса. Представлены результаты расчетов модельных задач.
Introduction. Remote ischemic preconditioning (RIPC) is a promising intervention for protecting organs and tissues from damage. The aim of this study was to evaluate the diagnostic efficacy of angioneuroprotective biomarkers in patients with extrapyramidal movement disorders undergoing magnetic resonance-guided focused ultrasound (MRgFUS) thermocoagulation. Materials and Methods . 42 patients were enrolled in a prospective, randomized, blinded study with an active control (sham RIPC). Prior to the procedure, patients were randomized into either the RIPC group (cuff pressure set at systolic blood pressure + 50 mm Hg, n=21) or the sham RIPC group (cuff pressure set at diastolic blood pressure, n=21). The protocol in both groups consisted of three 5-minute cycles of the cuff inflation (preconditioning or its imitation) each followed by a 5-minute rest intervals. Levels of biomarkers (TRIM72, S100B, ubiquitin, Lp-PLA2, endothelin-1) were measured in blood serum before and 1 hour after MRgFUS procedure. Results. Comparison of post-procedural biomarker levels revealed statistically significant differences: the S100B levels were higher in the sham RIPC group (1.34 ng/mL) compared to the RIPC group (0.44 ng/mL, p<0.001) and the ubiquitin level (5.8 ng/mL) were also higher than in the RIPC group (4.73 ng/mL) (p = 0.008). These findings indicate that prior RIPC is associated with suppression of biomarkers of neuroglial damage (S100B) and proteolytic stress (ubiquitin) released in response to thermocoagulation. Conclusion . RIPC is associated with reduced levels of S100B and ubiquitin during MRgFUS thermocoagulation, demonstrating a cytoprotective effect by mitigating blood-brain barrier and neuronal damage.
Cold spray (CS) is a progressive method for the deposition of metals and alloys whose principles involve considerable plastic deformation of the produced material at extreme strain rates. Positron annihilation spectroscopy (PAS) is an analytical technique capable of studying deformation on the atomic scale level, even in extremely deformed materials. In our study, the PAS method was used to characterize the microstructure and quantify the open-volume defects in four cold sprayed metals: Al, Cu, Ni, and Ti. As counterparts, bulk samples of these materials with ultra-fine-grained structures were also produced by high-pressure torsion (HPT), a process exceeding cold spray in the total deformation, but having several orders of magnitude smaller strain rates, and by a traditional cold rolling process. The results show that the CS and HPT processes lead to the formation of similar lattice defects (dislocations and vacancy clusters), and both exhibit significantly higher dislocation densities than conventionally cold-rolled materials. Further, the vacancy clusters present in CS and HPT materials were not present in the rolled counterparts due to the lower vacancy production rate.
The results of the study on determining the true fracture stresses of cylindrical samples with an ultrafine-grained structure of alloy 6001 obtained by the ECAP-C method are presented. These results are compared with similar data for a coarse-grained structure of the same alloy produced through standard heat treatment. This work was conducted to accurately describe the mechanical behavior of the material in both the coarse-grained (CG) and ultrafine-grained (UFG) states. The analysis revealed that the true strain to failure in the artificial aging (AA) state and the UFG state of alloy 6101, taking measurement errors into account, is the same. However, the true fracture stress of samples with a UFG structure is significantly higher than that of samples with an AA structure. The increase in strength and yield point resulting from ECAP-C processing is determined by the reduction in grain size according to the Hall–Petch relationship. An explanation for the increase in true fracture stress of samples during grain refinement is proposed on the basis of a compilation of the Hall–Petch relationship and the Zener–Stroh model, which involves a criterion for pore formation in particles when the stresses at the matrix/particle interface reach critical values.
