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.

First record of Rhabdoceras suessi (Ammonoidea, Late Triassic) from the Transylvanian Triassic Series of the Eastern Carpathians (Romania) and a review of its biochronology, paleobiogeography and paleoecology

Abstract The occurrence of the heteromorphic ammonoid Rhabdoceras suessi Hauer, 1860, is recorded for the first time in the Upper Triassic limestone of the Timon-Ciungi olistolith in the Rarău Syncline, Eastern Carpathians. A single specimen of Rhabdoceras suessi co-occurs with Monotis (Monotis) salinaria that constrains its occurrence here to the Upper Norian (Sevatian 1). It is the only known heteromorphic ammonoid in the Upper Triassic of the Romanian Carpathians. Rhabdoceras suessi is a cosmopolitan species widely recorded in low and mid-paleolatitude faunas. It ranges from the Late Norian to the Rhaetian and is suitable for high-resolution worldwide correlations only when it co-occurs with shorter-ranging choristoceratids, monotid bivalves, or the hydrozoan Heterastridium. Formerly considered as the index fossil for the Upper Norian (Sevatian) Suessi Zone, by the latest 1970s this species lost its key biochronologic status among Late Triassic ammonoids, and it generated a controversy in the 1980s concerning the status of the Rhaetian stage. New stratigraphic data from North America and Europe in the subsequent decades resulted in a revised ammonoid biostratigraphy for the uppermost Triassic, the Rhaetian being reinstalled as the topmost stage in the current standard timescale of the Triassic. The geographic distribution of Rhabdoceras is compiled from published worldwide records, and its paleobiogeography and paleoecology are discussed

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

Assessment of Acetabulum Deformity During Preoperative Planning for Hip Arthroplasty

Purpose of the study — to improve the two-dimensional planning of total hip joint arthroplasty to ensure precise positioning of the acetabular component in the deformed acetabulum. Materials and methods. Features of roentgenological anatomy of acetabulum and its coverage were studied on 1058 hip joint x-rays in the AP view in accordance with the procedure developed by the authors to define acetabular square — the site of standard positioning of a spherical femoral head in the acetabulum or of a hemispherical acetabular component. The method consisted of identifying the apex of “teardrop” figure; the most lateral points of the pelvic terminal line and roof of the acetabulum; superior part of the acetabular cavity; medial and inferior points of acetabular coverage, and building the sides of acetabular square — medial, inferior, lateral and superior boundary lines. Connection of “teardrop” apex and lateral point of the pelvic terminal line formed the medial side of acetabular square, and a perpendicular to that line drawn through the “teardrop” apex to its inferior side. The lateral side was drawn either through the intersection of the ascending diagonal line — bisector from the top of the “teardrop” figure with the contour of the acetabulum roof, or was a part of the projection of the most lateral point of the acetabular roof on the inferior side of the square. The superior side was a perpendicular connecting the intersection of the ascending diagonal and lateral bounding lines with the medial side of the acetabular square. The area of the deformed acetabular cavity located outside of the acetabular square was assessed as the acetabular defect. Results. Method of defining the acetabular square allowed to identify types of ratios between acetabular cavity and acetabular coverage in transverse (9 types) and longitudinal (7 types) direction. Combination of transverse ratio of acetabular cavity and coverage with longitudinal type allowed to define the options of acetabular deformities in two-dimensional view. The authors identified 25 types of acetabular deformities. Bone defects of acetabular walls were of the major importance among all anatomical features. Cranial defect of acetabulum was observed in 450 cases, medial wall defect — in 38 cases, defect including cranial and medial areas — in 7 cases. Conclusion. The method suggested by the authors to determine acetabular square and acetabular deformity variations allows to screen the anatomical features of the acetabulum during two-dimensional preoperative planning and to make an informed decision on the need to use other planning techniques. The type of acetabular deformity identified during preoperative planning allows to elaborate the indications for replacement of acetabular bone defects and/or resection of acetabular osteophytes

Assessment of cost-effectiveness of improving energy performance in networks with semiconductor converters

Сарваров Анвар Сабулханович, профессор кафедры «Автоматизированный электропривод и мехатроника», Магнитогорский государственный технический университет им. Г.И. Носова, г. Магнитогорск; [email protected]. Шевырёв Юрий Вадимович, д-р техн. наук, профессор кафедры «Электрификация и энергоэффективность горных предприятий», Московский государственный горный университет, г. Москва; [email protected]. Фёдоров Олег Васильевич, д-р техн. наук, профессор кафедры «Управление инновационной деятельностью», Нижегородский государственный технический университет им. Р.Е. Алексеева; fedorov_o@ mail.ru. A.S. Sarvarov, Nosov Magnitogorsk State Technical University, Magnitogorsk, Russian Federation, [email protected], Yu.V. Shevyrev, Moscow State Mining University, Moscow, Russian Federation, [email protected], O.V. Fedorov, Nizhny Novgorod State Technical University n.a. R.E. Alekseev, Nizhny Novgorod, Russian Federation, [email protected]Рассмотрены различные способы повышения качества электроэнергии в сетях с полупроводниковыми преобразователями. Среди них выделены вопросы применения сетевых реакторов, переход к многопульсным схемам, использование фильтрокомпенсирующих устройств со ступенчатым и косвенным регулированием. При проведении оценки современных средств улучшения качества электроэнергии выделяются преобразователи частоты с активным выпрямителем и полупроводниковые источники реактивной мощности на полностью управляемых силовых ключах. Технико-экономические аспекты применения фильтрокомпенсирующих устройств рассмотрены для двух случаев: питание от линии электропередачи и от системы автономного электроснабжения. Приведены результаты инструментальных исследований на одном из нефтепромыслов при широком использовании центробежных электронасосов с частотно-регулируемым приводом, представленные в виде осциллограмм напряжения и тока на вводе распределительного устройства 6 кВ их спектральный состав. Из графиков видно, что форма напряжений и токов существенно искажена. При выполнении технико-экономических расчетов различных вариантов выделяются основные экономические составляющие показателей, такие как капитальные и текущие эксплуатационные затраты. При отличии рассматриваемых систем по уровню качества электроэнергии к приведенным затратам прибавляется величина убытка от снижения её качества. При невозможности вычисления убытка учитываются затраты на приобретение регуляторов качества электроэнергии. При питании от системы автономного электроснабжения рассмотрен широко применяемый на практике вариант, когда в качестве автономного источника энергии применяются дизель-генераторы. В этом случае в состав приведенных затрат, в отличие от предыдущего, входят годовые затраты на производство электрической энергии дизель-генераторами. Приведены методы расчета затрат на техническую реализацию средств повышающих качество электроэнергии в питающих сетях, реализованных в системах питания от линии электропередачи и в системах при автономном питании. Показан пример расчета, в котором реализована методика определения области эффективного применения регуляторов качества электроэнергии. Various methods of improving the quality of electricity networks with semiconductor converters are discussed. Among them, the use of network reactors, transition to multi-pulse schemes, the use of filtercompensating devices with a step and indirect regulation. The allocation of modern means of improving the quality of electricity allocates frequency converters with an active rectifier and semiconductor sources of reactive power on a fully controlled power switches. Technical and economic aspects of the use of filtercompensating devices are discussed for two cases: the power of the power lines and the system of autonomous power supply. The results of instrumental research at one of the oil-extracting enterprises with extensive use of centrifugal pumps with variable frequency drive are presented in the form of voltage and current waveforms at the input of 6 kV- distribution device, their spectral composition. The graphs show that the shape of the voltages and currents is strongly distorted. During the execution of the technical-economic calculations of various options main indicators of economic components, such as capital and ongoing operating costs, are discussed. In addition to the differences between the systems in terms of quality of electricity, the amount of impairment loss of its quality is added to the described expenses. If it is unable to calculate the losses, the cost of purchasing power quality controls is calculated. When powered from a stand-alone power supply system one option is widely used in practice, when diesel generators are used as an autonomous source of energy. In this case, presented costs, unlike the previous one, consist of annual costs for the production of electric energy by diesel generators. Methods of calculating the costs of technical implementation of means improving the quality of electricity in the power network implemented in the power systems of the power lines and systems with autonomous power supply are discussed. An example of the calculation, which implements the method of determining the effective use of power quality controls, is given