Cr2O3/Al-Al2O3 composite catalysts for hydrocarbons dehydrogenation prepared from aluminum nanopowder

Aluminum nanopowder (10–150 nm) was treated hydrothermally in mild conditions (60–95 °C, at atmospheric pressure), and an aluminum-alumina composite with high porosity and specific surface area was obtained. Cr2O3/Al-Al2O3 catalysts were prepared using the aluminum-alumina composite by impregnation techniques and tested in dehydrogenation of C4-hydrocarbons. It was shown that aluminum-alumina composites had high chemical and phase purity, specific surface area of 150–350 m2/g and the average pore size of 8–13 nm, that is favorable for application as support for catalysts. Cr2O3/Al-Al2O3 catalysts had high activity and selectivity in dehydrogenation of n- and i-butane (conversion of 44–80 mol.% and selectivity >85% at temperatures of 540–610 °C), that is comparable ones for commercial catalysts for CATOFIN, STAR processes

Excess wing in glass-forming glycerol and LiCl-glycerol mixtures detected by neutron scattering

The relaxational dynamics in glass-forming glycerol and glycerol mixed with LiCl is in-vestigated using different neutron scattering techniques. The performed neutron spin-echo experiments, which extend up to relatively long relaxation-time scales of the order of 10 ns, should allow for the detection of contributions from the so-called excess wing. This phenomenon, whose microscopic origin is controversially discussed, arises in a variety of glass formers and, until now, was almost exclusively investigated by dielectric spectros-copy and light scattering. Here we show that the relaxational process causing the excess wing also can be detected by neutron scattering, which directly couples to density fluctua-tions.Comment: 8 pages, 6 figure

Observation of Fragile-to-Strong Dynamic Crossover in Protein Hydration Water

At low temperatures proteins exist in a glassy state, a state which has no conformational flexibility and shows no biological functions. In a hydrated protein, at and above 220 K, this flexibility is restored and the protein is able to sample more conformational sub-states, thus becomes biologically functional. This 'dynamical' transition of protein is believed to be triggered by its strong coupling with the hydration water, which also shows a similar dynamic transition. Here we demonstrate experimentally that this sudden switch in dynamic behavior of the hydration water on lysozyme occurs precisely at 220 K and can be described as a Fragile-to-Strong dynamic crossover (FSC). At FSC, the structure of hydration water makes a transition from predominantly high-density (more fluid state) to low-density (less fluid state) forms derived from existence of the second critical point at an elevated pressure.Comment: 6 pages (Latex), 4 figures (Postscript

The Hydration Structure at Yttria-Stabilized Cubic Zirconia (110)-Water Interface with Sub-Angstrom Resolution

The interfacial hydration structure of yttria-stabilized cubic zirconia (110) surface in contact with water was determined with ~0.5 Å resolution by high-resolution X-ray reflectivity measurement. The terminal layer shows a reduced electron density compared to the following substrate lattice layers, which indicates there are additional defects generated by metal depletion as well as intrinsic oxygen vacancies, both of which are apparently filled by water species. Above this top surface layer, two additional adsorbed layers are observed forming a characteristic interfacial hydration structure. The first adsorbed layer shows abnormally high density as pure water and likely includes metal species, whereas the second layer consists of pure water. The observed interfacial hydration structure seems responsible for local equilibration of the defective surface in water and eventually regulating the long-term degradation processes. The multitude of water interactions with the zirconia surface results in the complex but highly ordered interfacial structure constituting the reaction front.ope

Mathematical model of diesel engine characteristics for determining the performance of traction dynamics of wheel-type tractor

Wheel-type tractors carry out a range of processing operations, with the exception of early spring work, when caterpillar tractors are used to reduce the compaction effect on the soil. Therefore, to plan the costs and reserves associated with fuel consumption, it is necessary to have an estimate of the fuel economy of the tractor in basic agricultural operations. An objective assessment of fuel consumption requires a mathematical model that describes the fuel characteristics of the engine, taking into account the speed and load torque in a wide range of variation. Verification of the model is possible only with experimental data. Since the efficiency and fuel economy of a tractor depends not only on engine performance, but also on the perfection of the transmission, the running system and the rational choice of speed, it is necessary to take into account the time-varying nature of the tractor’s traction load. The complex of agricultural operations can be divided into characteristic cycles of load change over time. This principle is the basis of PowerMix test cycles, which are conducted on a concrete track to ensure repeatability of the experiment. The use of the variable load on the tractor in the PowerMix tests is positive, but in actual field tests the results may differ due to the instability of the soil properties. On the other hand, PowerMix field cycles can be taken as standard test loads in the simulation of tractor traction tests on the ground

International Cooperation as a Tool to Improve the Quality of Construction Education in the Tambov Region

В российском законодательстве в сфере образования четко определены цели международного сотрудничества, развитие которого необходимо для повышения уровня интернационализации высшего учебного заведения и, как следствие, улучшения качества подготовки высококвалифицированных специалистов. В статье описан опыт организации международной деятельности в Тамбовском государственном техническом университете на примере реализации проекта “MARUEEB”, направленного на разработку образовательной программы по подготовке магистров в области энергоэффективного строительства. Раскрываются основные этапы проекта, включающие анализ результатов анкетирования работодателей, разработку содержательной части программы, академическую мобильность преподавателей, а также межвузовское взаимодействие в подготовке учебно-методического обеспечения образовательного процесса. Отмечается, что опыт зарубежных вузов-партнеров и производственных компаний в области энергосбережения способствует расширению профессиональных компетенций выпускников ТГТУ.The objectives of international cooperation in the field of education are clearly defined in Russian legislation. It contributes to increasing the level of internationalization of universities and improving the quality of training. The article de-scribes the experience of organization of international activities in Tambov State Technical University by the example of the implementation of the project “MARUEEB”. It is aimed at developing an educational program for the preparation of masters in the field of energy-efficient construction. The main stages of the project are described: the analysis of the results of the survey of employers, the development of the content of the study program, the academic mobility of teachers and the interaction of universities in the preparation of textbooks for the educational process. It is noted that the experience of foreign partner-universities and production companies in the field of energy efficiency contributes to the expansion of professional competencies of graduates of TSTU

The results of treatment of patients with an acute cholecystitis and perivesical complications

Objective. To improve the quality of diagnosis and results of treatment in patients, suffering an acute cholecystitis, complicated by formation of perivesicular infiltrate, abscess and Mirizzi’s syndrome. Materials and methods. Results of diagnosis and surgical treatment of 694 patients, suffering an acute cholecystitis, ageing 38 - 87 yrs old, admitted to the clinic in 2010 - 2019 yrs, were analyzed. The examination have included general clinical investigation, biochemical investigations of the blood, ultrasonographic investigation of a gallbladder and extrahepatic biliary ducts, and in accordance to certain indications – computer tomography, papilloscopy and endoscopic retrograde cholangiopancreaticography. Results. Of 694 patients, suffering an acute cholecystitis in 541 (78.0%) perivesical complications were revealed. In 215 (31.0%) patients perivesical infiltrate was formed, while in 76 (11.0%) – perivesical abscess. In 250 (36.0%) patients an acute cholecystitis have developed on background of obturation jaundice, caused by choledocholithiasis in 138 patients, while in 98 patients Mirizzi’s syndrome Type I was diagnosed, and in 14 - Mirizzi’s syndrome Type II. Of 215 patients with an acute cholecystitis and perivesical infiltrate in 84 laparoscopic cholecystectomy was performed after course of antibacterial therapy, while in 131 patients – open cholecystectomy. In all 76 patients with perivesical abscess open cholecystectomy was performed. Of 138 patients, suffering obturation jaundice on background of choledocholithiasis in 82 endoscopic retrograde cholangiopancreaticography with simultaneous lithoextraction and subsequent laparoscopic cholecystectomy was conducted. In 56 patients naso-biliary drainage was installed and was held in place till calculi from common biliary duct have gone away and subsequent laparoscopic cholecystectomy performed. Of 98 patients with an acute cholecystitis and confirmed Mirizzi’s syndrome Type I in 95 laparoscopic cholecystectomy was performed, while in 3 – the open one. Of 14 patients, suffering Mirizzi’s syndrome Type II, in 10 open operation was done with sanation of biliary ducts and plasty of a common biliary duct defect, while in 4 – laparoscopic cholecystocholedocholithotomy with restoration of the bile physiological passage. Conclusion. In 78.0% patients with an acute cholecystitis perivesical complications were diagnosed. Of 531 patients with perivesical infiltrate, choledocholithiasis and Mirizzi’s syndrome in 321 (60.5%) laparoscopic operations on biliary ducts were accomplished. Open laparotomy was performed in 210 (39.5%) patients. In all the patients, suffering Mirizzi’s syndrome of both Types, physiologic passage of bile was preserved