Investigation of the Process of Methane-Oxygen Combustion in Steam Under the Atmospheric Pressure

In the article presented results of combustion methane-oxygen mixtures in the slightly superheated water steam under the atmospheric pressure. It is shown that exist dependence of flow rate combustible mixture and steam ratio (G[g.s]./G[s]) on the composition of the reacting mixture at the outlet of combustion chamber. There is a trend of increasing CO2 concentration in the reacting mixture at the outlet of combustion chamber with increase of G[g.s]./G[s]

Water uptake and transport properties of La1-xCaxScO3-α proton-conducting oxides

In this study, oxide materials La1-xCaxScO3-α (x = 0.03, 0.05 and 0.10) were synthesized by the citric-nitrate combustion method. Single-phase solid solutions were obtained in the case of calcium content x=0.03 and 0.05,whereas a calcium-enriched impurity phasewas found at x=0.10. Water uptake and release were studied by means of thermogravimetric analysis, thermodesorption spectroscopy and dilatometry. It was shown that lower calcium content in the main phase leads to a decrease in the water uptake. Conductivity wasmeasured by four-probe direct current (DC) and two-probe ascension current (AC)methods at different temperatures, pO2 and pH2O. The effects of phase composition,microstructure and defect structure on electrical conductivity, as well as correlation between conductivity and water uptake experiments, were discussed. The contribution of ionic conductivity of La1-xCaxScO3-α rises with decreasing temperature and increasing humidity. The domination of proton conductivity at temperatures below 500 °C under oxidizing and reducing atmospheres is exhibited. Water uptake and release as well as transport properties of La1-xCaxScO3-α are compared with the properties of similar proton electrolytes, La1-xSrxScO3-α, and the possible reasons for their differences were discussed. © 2019 by the authors.Russian Science Foundation, RSF: 16-13-00053Government Council on Grants, Russian FederationMinistry of Education and Science of the Republic of KazakhstanFunding: The research was partially supported by the Russian Science Foundation (Grant №16-13-00053) and the Ministry of Education and Science of the Republic of Kazakhstan (Project No. AP05130148). The education activity of Ph.D. and students involved into this work is supported by Act 211 of Government of the Russian Federation, agreement No. 02.A03.21.0006

Oxygen isotope exchange in oxides La2−xCaxZr2O7−α

The oxygen isotope exchange method with equilibration of the isotope composition of the gas phase was used to obtain temperature dependences of oxygen diffusion coefficients and oxygen heterogeneous exchange rates with oxides La2−xCaxZr2O7−α (x = 0; 0.05; 0.1) in the temperature range of 600–900 °C and oxygen partial pressure equals 1 kPa. The oxygen diffusion coefficient was found to increase with increasing temperature and calcium content in the oxide. It is shown that an increase in the concentration of calcium leads to a decrease in the rate of dissociative adsorption through the segregation of the dopant on the surface and blocking of the active adsorption sites La-O, and also to an increase in the rate of incorporation due to an increase in the concentration of oxygen vacancies.В работе методом изотопного обмена кислорода с уравновешиванием изотопного состава газовой фазы исследована кинетика обмена кислорода газовой фазы с оксидами La2−xCaxZr2O7−α (x = 0; 0.05; 0.1), имеющих структуру пирохлора. Получены температурные зависимости коэффициентов диффузии и скоростей обмена кислорода с исследуемыми оксидами в температурном интервале 600–900 °C и давлении кислорода 1 кПа. Установлено, что с ростом температуры и с повышением содержания кальция в оксиде коэффициент диффузии кислорода увеличивается. Показано, что увеличение концентрации кальция приводит к уменьшению скорости диссоциативной адсорбции из-за сегрегации допанта на поверхности и, как следствие, блокирования активных центров адсорбции La-O, а также увеличению скорости инкорпорирования вследствие увеличения концентрации кислородных вакансий

Влияние отмены ИАПФ/БРА на риск развития послеоперационных осложнений в абдоминальной хирургии

A significant proportion of patients undergoing non-cardiac surgery receive therapy with angiotensin converting enzyme (ACE) inhibitors/angiotensin II receptor blockers (ARBs), which are usually prescribed for treatment of arterial hypertension and CHF. Current guidelines fail to provide clear consensus on whether it is worth discontinuing ACEi/ARBs before non-cardiac surgery. The aim of this research was to assess the contribution of pre-op ACEi/ARBs withdrawal to the development of postoperative complications in patients after abdominal surgery using data from STOPRISK database.Materials and methods. Data of 1945 patients from of the STOPRISK database was used for the analysis. Patients were retrospectively divided into two groups: first group (N=471, 24.2%) included patients subjected to ACEi/ARBs withdrawal 24 hours before surgery, second group (N=1474, 75.8%) included patients continuing on ACEi/ARBs therapy. The 30-day outcomes were analyzed — postoperative complications (acute kidney injury, acute respiratory distress syndrome, anastomosis failure, arrhythmias, circulatory arrest, cardiogenic pulmonary edema, postoperative delirium, myocardial infarction, pneumonia, ileus, postoperative bleeding, pulmonary embolism, acute cerebrovascular accident, wound infection) and mortality. We were not evaluating intraoperative and postoperative arterial hypotension and hypertension, we analyzed the use of vasopressors as a surrogate marker. ACEi/ARBs re-initiation after surgery was not evaluated.Results. One or more post-operative complications were documented in 113 patients (5.8%). Only postoperative delirium was more common in patients (1.06% vs. 0.27%, P=0.027) after ACEi/ARBs withdrawal 24 hours before surgery, the difference reached statistical significance. Sub-analysis in the group of patients with arterial hypertension as the only comorbidity showed no statistically significant differences in the outcomes. Sub-analysis in the group of patients with CFH showed higher incidence of postoperative delirium after ACEi/ARBs withdrawal (2.68% vs. 0.6%, P=0.023). The logistic regression analysis showed that the risk of developing postoperative delirium is influenced by age, vasopressor support, and ACEi/ARBs withdrawal (the area under the curve for the model was 0.92 (0.90–0.93).Conclusion. Rates of pre-op ACEi/ARBs withdrawal (24.2%) are consistent with published data. In the entire cohort, ACEi/ARBs withdrawal resulted in higher incidence of postoperative delirium, as well as in the subgroup of patients with CHF, while ACEi/ARBs withdrawal in the subgroup of patients with arterial hypertension had no influence on postop complications.ACEi/ARBs withdrawal, along with hemodynamic instability and older age, contributes to the development of postoperative delirium, which is the subject of future research. Значительное число пациентов, подвергающихся внесердечным операциям, получает терапию ингибиторами ангиотензинпревращающего фермента (ИАПФ)/блокаторами рецепторов ангиотензина II (БРА), которые обычно назначают в качестве антигипертензивных препаратов и для лечения ХСН. В современных руководствах нет единого мнения о том, стоит ли отменять ИПФ/БРА перед внесердечными операциями.Цель работы — изучение вклада отмены ИАПФ/БРА в развитие послеоперационных осложнений у пациентов в абдоминальной хирургии по данным базы STOPRISK.Методы исследования. В анализ включили данные 1945 пациентов базы данных STOPRISK, которых ретроспективно разделили на пациентов, у которых ИАПФ/БРА отменяли за 24 ч до операции (n=471, 24,2%) и остальных пациентов (n=1474, 75,8%), у которых прием продолжался вплоть до оперативного вмешательства. Изучали 30-дневный исход — послеоперационные осложнения (острое повреждение почек, острый респираторный дистресс-синдром, несостоятельность анастомоза, аритмии, остановка кровообращения, кардиогенный отек легких, послеоперационный делирий, инфаркт миокарда, пневмония, парез кишечника, послеоперационное кровотечение, тромбоэмболия легочной артерии, острое нарушение мозгового кровообращения, раневая инфекция) и летальность. В исследовании не оценивали частоту интраоперационной и послеоперационной гипотензии и гипертензии, применяли суррогатный показатель — частоту применения вазопрессоров. Не оценивали возобновление терапии ИАПФ/БРА в послеоперационный период Результаты. Наличие одного и более осложнения регистрировали у 113 пациентов (5,8%). Статистически значимыми были различия только в частоте послеоперационного делирия — он чаще встречался в группе пациентов, у которых ИАПФ/БРА отменяли за 24 часа до операции (1,06% против 0,27%, р=0,027). При проведении субанализа в подгруппе пациентов, где сопутствующие заболевания были представлены изолированной гипертонической болезнью, статистически значимых различий в исходах не отметили.Субанализ у пациентов, в структуре сопутствующих заболеваний которых присутствовала хроническая сердечная недостаточность, показал большую частоту послеоперационного делирия в группе пациентов, у которых ИАПФ/БРА отменяли (2,68% против 0,6%, р=0,023).Проведенный логистический регрессионный анализ показал, что на риск развития послеоперационного делирия влияют возраст, вазопрессорная поддержка, отмена ИАПФ/БРА (площадь под кривой для модели составила 0,92 (0,90–0,93).Заключение. Частота отмены ИАПФ/БРА (24,2%) соотносится с мировыми данными. В общей когорте отмена ИАПФ/БРА приводила к большей частоте развития послеоперационного делирия, субанализ в группе пациентов с хронической сердечной недостаточностью подтвердил эту закономерность, в группе же пациентов с гипертонической болезнью, отмена ИАПФ/БРА, не влияла на исход. Наряду с гемодинамической нестабильностью и пожилым возрастом, отмена ИАПФ/БРА, вносит вклад в развитие послеоперационного делирия, что требует дальнейшего изучения.

THE REDUCTION ANTHROPOGENIC EMISSION AT THE COMBUSTION OF COALS AND COAL PROCESSING WASTE AS A COMPONENT COAL-WATER SLURRY CONTAINING PETROCHEMICALS

Coal-fired power stations produce of tens millions tons of ash and slag waste, and hundreds of millions cubic meters of gas emissions annual. As part of this work analysis of current methods to reduce anthropogenic emissions in the ash produced by the processing (combustion) of traditional coal fuels was made, advantages and disadvantages of each methods were highlighted. It is shown that both low levels of emissions in the ash and combustion products is difficult to ensure. As a result, it was proposed to use promising coal-water slurry containing petrochemicals instead of pulverized coal. The experimental research into maximum concentrations of anthropogenic emissions from the combustions of coal-water slurry containing petrochemicals. The experimental research into maximum concentrations of anthropogenic emissions by the combustions of coal-water slurry containing petrochemicals basedfilter-cakes were conducte

Multidisciplinary approach to the treatment of patients with periprosthetic joint infection of the hip complicated by injury to the great vessels

Introduction Total counts of total hip arthroplasty (THA) have been increasing for several decades, and the procedures are associated with considerable risk of intra- and postoperative complications. Vascular complications are defined as multiple pathological conditions. They are subdivided into acute adverse events such as intraoperative bleeding, acute ischemia and hematoma and chronic complications such as pseudoaneurysms and arteriovenous fistulas which can cause late ischemic events. A specialized and well-trained multidisciplinary team is required to perform surgical interventions due to the small number of intravascular lesions. The objective was to demonstrate findings of clinical, instrumentation methods and staged treatment of patients with periprosthetic joint infection (PJI) of the hip and complications associated with injury to the great vessels. Material and methods We report two cases of vascular complications in patients with PJI and migration of femoral components into the lesser pelvis. Results An integrated approach to the diagnosis and treatment of patients with PJI and complications associated with injury to the great vessels helped to avoid lethal outcomes of the Girdlestone operation. Discussion Revision THA requires careful planning and an interdisciplinary approach with the help of a clinical pharmacologist, microbiologist, plastic or angiosurgeon. PJI is associated with a high risk of recurrence that would require two-stage, three-stage surgical interventions. With the bone deficiency of the acetabulum and the proximal femur the Girdlestone operation is performed as the final procedure with resultant significant decrease in the functional adaptation of patients. Conclusion Careful preoperative preparation of patients with unstable hip replacement components including migration of the acetabular component into the pelvic cavity and associated PJI would help to avoid such a devastating complication as great vessel injury