Obtaining the fine-grained silicon carbide, used in the synthesis of construction ceramics

AbstractSilicon carbide is used in the production of construction and temperature-resistant goods, capable of withstanding high mechanical and thermal loads. During recent times, silicon carbide has been frequently used in the electronics industry. Since sintered silicon carbide has increasingly been used as a replacement for metal components of various devices, the process of obtaining compact goods from silicon powder has become the defining factor in the technology used for its synthesis. The selection of conditions in which the sintering is conducted depends on granulometric structure, the form and the surface condition of the initial powder. The work consists of the synthesis of silicon carbide powder using the purified form of metallurgical silicon powder and soot. The qualities of testing samples were studied, where silicon carbide was obtained using established technology, from mechanically activated elementary, fine-grained silicon and soot, by pyrolytic synthesis. It was demonstrated that synthesis produces highly pure silicon carbide powder, (α- and β-phases) with a granulometric composition that allowed subsequent sintering to produce high quality compact goods. It was established that the content of silica in synthesized silicon carbide powder does not exceed 1–2% of the total mass

Catalytic Oxidation of Volatile Organic Compounds in Industrial Off-Gases

Processes and apparatuses for catalytic oxidation of VOCs in industrial off-gases are described, including steady state and unsteady state processes, a combined adsorption-catalytic process and an advanced method of ozone induced oxidation for low concentrated exhausts. On the basis of research and development works a series of catalytic incinerators, operating in steady state and unsteady state mode, of various capacity were designed, constructed and tested in the purification of ventilation air and off-gases from VOCs. The principles of operation of different types of catalytic incinerators and possible areas of application are discussed. For VOC concentrations 150-1000 mg/m3 unsteady state catalytic incinerators of KART type should be used, for concentrations 1000-3000 mg/m3 steady state KROT apparatuses are recommended, and for concentrations over 3000 mg/m3 up to 7000 mg/m3 installations TKM-250. It is shown that for the purification of low concentrated gases with the content of organic vapors below 150 mg/m3 adsorptioncatalytic method or catalytic oxidation with ozone in the installation OKA-3000 are most effective. Main kinetic dependencies of the ozone induced oxidation of toluene and acetone over copper oxide catalyst are given and discussed. It is shown that the efficiency of this method of VOCs removal is based on low operation temperature 313-343 K, by contrast to conventional catalytic incineration by air requiring preliminary heating of the gases to 523-573 K. A special consideration is given to adsorptive damping as an efficient method for leveling the VOCs concentrations in the real industrial exhausts directed to the catalytic treatment. The use of adsorptive dampers filled with carbon allows elimination of large deviations of pollutant concentrations in the gas entering the catalyst bed, thus increasing the VOCs removal efficiency from average values. For calculations of adsorptive dampers, an equation describing the profiles of VOC concentrations in gas phase along the length of the adsorbate bed in the damper was derived

Прогностическое значение коморбидной патологии в прогрессировании хронической обструктивной болезни легких в зависимости от фенотипических особенностей заболевания

Background: Chronic obstructive pulmonary disease (COPD) is characterized by progressive limitation of airflow rate, hyperergic inflammatory response of the respiratory tract, and systemic manifestations. Prognosis of the disease depends on the severity of these pathogenetic components. FEV1 which characterizes the speed limit airflow do not allow predicting the rate of COPD progression. Aims: comparison of the prognostic significance of such clinical parameters as frequency of exacerbations and the development of comorbid diseases to assess the nature of COPD progression by using different classification approaches. Materials and methods: The prospective comparative study included 98 patients with COPD. In the framework of the study protocol, 2 visits were required when a practitioner recruited patients who met inclusion/exclusion criteria, obtained the signed informed consent, collected the anamnestic data, and performed basic procedures of the study: spirometry, 6-minute stepper test, assessment of dyspnea on questionnaire mMRC, body plethysmography, lung diffusion capacity study, dopplerechocardiography, tomography of the chest. Visit 2 was conducted in 12 months after the first one to assess the dynamics of the disease. The dynamics of the disease was considered negative if, upon repeated examination, the patient was referred to the group with more severe COPD. Results: Our study demonstrates that comprehensive assessment of such factors as the frequency of COPD exacerbations in the preceding 12 months and the presence of comorbid diseases in a patient is reasonable for assessment of disease severity and determination of disease prognosis. At the same time the frequency of COPD exacerbations as one of the evaluated factors is most strongly associated with disease progression. Conclusions: Thus, a practitioner is recommended to use the proposed additional clinical criteria to assess the severity and degree of progression of COPD.Обоснование. Хроническая обструктивная болезнь легких (ХОБЛ) — хроническое заболевание с прогрессирующим ограничением скорости воздушного потока, гиперергическим воспалительным ответом дыхательных путей и системными проявлениями. От степени выраженности этих патогенетических компонентов зависит прогноз течения заболевания. Показано, что характеристика ограничения скорости воздушного потока (объем форсированного выдоха за первую секунду) не позволяет с высокой вероятностью предсказать скорость прогрессирования ХОБЛ.Цель исследования: сравнение прогностической значимости таких клинических показателей, как частота обострений и развитие коморбидных заболеваний, для оценки характера прогрессирования ХОБЛ при использовании различных классификационных подходов.Методы. На основании единого протокола в проспективное сравнительное исследование включены 98 больных ХОБЛ. В рамках протокола предусмотрено 2 визита, включающих оценку соответствия пациента критериям включения/исключения, подписание информированного согласия, сбор анамнестических данных и выполнение основных процедур исследования (оценка функции внешнего дыхания, 6-минутный шаговый тест, оценка одышки по опроснику mMRC, бодиплетизмография, исследование диффузионной способности легких, допплерэхокардиография, компьютерная томография органов грудной клетки). Второй визит проводился через 12 мес после первого с целью оценки динамики заболевания, которая считалась отрицательной, если по прошествии одного года наблюдения пациента переводили в группу ХОБЛ с более тяжелым течением. Коморбидными заболеваниями считались снижение индекса массы тела менее 21, наличие остеопороза, анемии, сердечно-сосудистых заболеваний, язвенной болезни желудка, сахарного диабета 2-го типа.Результаты. Проведенное нами исследование свидетельствует о целесообразности комплексной оценки таких факторов, как частота обострений ХОБЛ за предшествующие 12 мес и наличие коморбидных заболеваний у больного при оценке текущей тяжести течения заболевания и определении его прогноза. При этом частота обострений ХОБЛ среди оцениваемых факторов наиболее сильно связана с прогрессированием заболевания.Заключение. Таким образом, практическому врачу предложены дополнительные клинические критерии для комплексной оценки тяжести и степени прогрессирования ХОБЛ

The Atmospheric Chemistry Suite (ACS) of Three Spectrometers for the ExoMars 2016 Trace Gas Orbiter

The Atmospheric Chemistry Suite (ACS) package is an element of the Russian contribution to the ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission. ACS consists of three separate infrared spectrometers, sharing common mechanical, electrical, and thermal interfaces. This ensemble of spectrometers has been designed and developed in response to the Trace Gas Orbiter mission objectives that specifically address the requirement of high sensitivity instruments to enable the unambiguous detection of trace gases of potential geophysical or biological interest. For this reason, ACS embarks a set of instruments achieving simultaneously very high accuracy (ppt level), very high resolving power (>10,000) and large spectral coverage (0.7 to 17 μm—the visible to thermal infrared range). The near-infrared (NIR) channel is a versatile spectrometer covering the 0.7–1.6 μm spectral range with a resolving power of ∼20,000. NIR employs the combination of an echelle grating with an AOTF (Acousto-Optical Tunable Filter) as diffraction order selector. This channel will be mainly operated in solar occultation and nadir, and can also perform limb observations. The scientific goals of NIR are the measurements of water vapor, aerosols, and dayside or night side airglows. The mid-infrared (MIR) channel is a cross-dispersion echelle instrument dedicated to solar occultation measurements in the 2.2–4.4 μm range. MIR achieves a resolving power of >50,000. It has been designed to accomplish the most sensitive measurements ever of the trace gases present in the Martian atmosphere. The thermal-infrared channel (TIRVIM) is a 2-inch double pendulum Fourier-transform spectrometer encompassing the spectral range of 1.7–17 μm with apodized resolution varying from 0.2 to 1.3 cm−1. TIRVIM is primarily dedicated to profiling temperature from the surface up to ∼60 km and to monitor aerosol abundance in nadir. TIRVIM also has a limb and solar occultation capability. The technical concept of the instrument, its accommodation on the spacecraft, the optical designs as well as some of the calibrations, and the expected performances for its three channels are described

Determination of the actual turbocharging characteristics of diesel engines using support vector machines (SVM)

The article proposes and justifies a method that allows solving the problem of determining the characteristics of turbocharging of diesel engines of agricultural tractors without the use of test benches. The proposed application of support vector machines (SVM) has a number of advantages over traditional methods for determining the characteristics of turbocharging of diesel engines under operating conditions of agricultural tractors and machines

The compatibility test of measurement data, produced by different magnetometers onboard an Earth artificial satellite

Abstract: Complicated mathematical models are usually used for processing measurements of the Earth magnetic field carried out onboard an Earth artificial satellite. It is desirable to verify the measurement data by humble tools before such processing. If a few onboard magnetometers made their measurements at the same instants, then one ought to check a simple geometrical compatibility of the measurement data. One can estimate constant shifts in the data and transition matrices between proper coordinate systems for each pair of magnetometers in case the check proved to be successful. Bellow, we described the method for checking the compatibility of the measurement data produced by two magnetometers. We illustrate the method by checking the compatibility of the magnetic measurements produced by the equipment Mirage onboard Foton M-2.Note: Research direction:Theoretical and applied problems of mechanic

Microbiological oropharyngeal patterns in patients with different phenotypes of chronic obstructive pulmonary disease

Persistent bronchial inflammation in chronic obstructive pulmonary disease (COPD) is considered the cause of ventilation disorders and related contamination with conditionally pathogenic microorganisms; the latter can proceed and transform into a full infection, which can aggravate and exacerbate COPD. The aim of the study was to evaluate the relations between the oropharyngeal microbiota in patients with COPD and the clinical, functional, and prognostic parameters of the disease. Materials and Methods. 64 patients with COPD were included in the study; the participants were scheduled to visit our clinic on two occasions. In the first visit, their medical history was studied in detail and the major examination procedures were conducted. Those included an assessment of the respiratory function, the 6-minute walk test, the degree of dyspnea by the Medical Research Council scale, body plethysmography, the diffusion capacity of the lungs, and a chest CT scan. The second visit took place 12 months after the first one to assess the changes in the course of the disease. The result was considered negative if, in the second examination, the patient‘s condition was found more severe. Oropharyngeal samples of all patients were sequenced to identify the V3–V4 variable sites of the 16S rRNA gene. Results. It is found that the microbiological oropharyngeal patterns in COPD patients depend on the source of micro-aspiration. In addition, the changes in the oropharyngeal microbiota correlate with the severity and prognosis of the disease, as well as the patient phenotype. Based on the data obtained by sequencing parts of the 16S rRNA gene, the role of oropharyngeal microbiota in determining the course and prognosis of COPD has been elucidated. Conclusion. The presented clinical and functional characteristics associated with oropharyngeal microbiota indicate that microaspirations from other body compartments not only affect the composition of oropharyngeal microbiota in patients with COPD but also have an important prognostic significance. © 2018, Nizhny Novgorod State Medical Academy. All rights reserved

Microbiological oropharyngeal patterns in patients with different phenotypes of chronic obstructive pulmonary disease

Persistent bronchial inflammation in chronic obstructive pulmonary disease (COPD) is considered the cause of ventilation disorders and related contamination with conditionally pathogenic microorganisms; the latter can proceed and transform into a full infection, which can aggravate and exacerbate COPD. The aim of the study was to evaluate the relations between the oropharyngeal microbiota in patients with COPD and the clinical, functional, and prognostic parameters of the disease. Materials and Methods. 64 patients with COPD were included in the study; the participants were scheduled to visit our clinic on two occasions. In the first visit, their medical history was studied in detail and the major examination procedures were conducted. Those included an assessment of the respiratory function, the 6-minute walk test, the degree of dyspnea by the Medical Research Council scale, body plethysmography, the diffusion capacity of the lungs, and a chest CT scan. The second visit took place 12 months after the first one to assess the changes in the course of the disease. The result was considered negative if, in the second examination, the patient‘s condition was found more severe. Oropharyngeal samples of all patients were sequenced to identify the V3–V4 variable sites of the 16S rRNA gene. Results. It is found that the microbiological oropharyngeal patterns in COPD patients depend on the source of micro-aspiration. In addition, the changes in the oropharyngeal microbiota correlate with the severity and prognosis of the disease, as well as the patient phenotype. Based on the data obtained by sequencing parts of the 16S rRNA gene, the role of oropharyngeal microbiota in determining the course and prognosis of COPD has been elucidated. Conclusion. The presented clinical and functional characteristics associated with oropharyngeal microbiota indicate that microaspirations from other body compartments not only affect the composition of oropharyngeal microbiota in patients with COPD but also have an important prognostic significance. © 2018, Nizhny Novgorod State Medical Academy. All rights reserved