132 research outputs found
Development of low-temperature thermochemical conversion reactors for coal power engineering
The main principles applied in developing a technology for low-temperature thermochemical conversion of brown coals to obtain fuel gas and semicoke intended for being fired in two-fuel power installations are considered on the basis of a set of experimental and calculated investigations. The obtained results are compared with the experimental data obtained using other methods and with the results of previous industrial tests. © 2013 Pleiades Publishing, Inc
The comparative study of selective laser trabeculoplasty effectiveness in phacic and pseudophacic patients with glaucoma
Purpose: To compare the effect of selective laser trabeculoplasty (SLT) in phacic and pseudophacic patients with glaucoma.Methods: A retrospective chart review was performed on 148 eyes of 139 patients with moderate primary open angle glaucoma (POAG). In the first group (pseudophacic group) 50 patients (50 eyes) underwent SLT at the period of 6 months and more after uneventful phacoemulsification cataract surgery, in the second (phacic group: 9 patients, 98 eyes) — 2‑3 months prior it. The post-laser follow up examinations were carried out at 1 day, 1 week, 1 month, 6 months and 12 months of follow-up. Average intraocular pressure (IOP), its decrease, and MD — mean deviation perimetric index — for phakic and pseudophakic eyes were compared statistically at each time period. A t-test was used to compare the IOP reduction between the phakic and pseudophakic groups.Results: IOP reduction in the pseudophakic group was statistically significant in the 1 month of follow up (from 28.3 mm Hg to 18.6mm Hg, p = 0.02), while in the phacic group its reduction was statistically significant in all steps of observation. The statistically significantdifference of IOP decrease level between groups was obtained in 1 week and 1 year after SLT. The MD perimetric index decreased by 3.89 dB (from –7.63 to –11.52) in the pseudophakic group and increased by 0.65 dB (from –4.31 to –3.66) in the phakic group.Conclusion: SLT is a safe and effective means of IOP reduction in pseudophakic glaucoma patients. However it seems to be more effective in lowering IOP if performed prior to cataract surgery: effect of SLT in pseudophakic eyes reduced through 6 months. SLT performed on phakic eyes might play a role in visual field improvement
Effect of the grain size on the precipitate distribution of the dispersion-strengthened СuСrZr alloy
Parameters of surface standing waves in fluidized bed apparat with different diameter
Regarding medium- and low-temperature processes of heterogeneous heterophase interaction in the units for cleaning from pollutants and trapping CO2, the analogy of the behavior of standing surface waves of an ideal liquid with oscillations of the surface of a fluidized bed is considered. Waves on the surface of a fluidized bed are formed when gas bubbles leave it and are one of the elements of the mechanism of self-sustained fluctuations of the entire mass of the bed. The frequency modes of the surface waves correspond to the main modes in the spectra of pressure fluctuations in the bed and depend on its geometry. The fluctuations of a bubble three-dimensional fluidized bed in apparatuses of different sizes are numerically simulated in a high-performance parallel computing mode using the Ansys Fluent program. Comparison of analytical calculations for fluid oscillations in a vessel with the results of numerical simulation of a fluidized bed and experimental data on the frequency of the emergence of bubbles and modes of surface waves is carried out. © Published under licence by IOP Publishing Ltd
Анализ детерминированных алгоритмов определения ориентации
Аналізуються детерміновані алгоритми визначення орієнтації з точки зору можливості аналізу інструментальних похибок. Запропоновано алгоритми, більш прості, ніж відомий алгоритм TRIAD. Отримано формули для подальшого аналізу інструментальних похибок алгоритмів. Виконано аналіз алгоритму QUEST.The deterministic algorithms of orientation determination are analyzed from the point of analysis instrumental errors view. Algorithms, more simple, are offered, than the known algorithm of TRIAD. Formulas are got for the further analysis of instrumental errors of algorithms. The analysis of algorithm of QUEST is executed.Анализируются детерминированные алгоритмы определения ориентации с точки зрения анализа инструментальных ошибок. Предложены алгоритмы, более простые, чем известный алгоритм TRIAD. Получены формулы для дальнейшего анализа инструментальных ошибок алгоритмов. Выполнен анализ алгоритма QUEST
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The electronic structure and the nature of the chemical bond in CeO2.
The X-ray photoelectron spectral structure of CeO2 valence electrons in the binding energy range of 0 to ∼50 eV was analyzed. The core-electron spectral structure parameters and the results of relativistic discrete-variational calculations of CeO8 and Ce63O216 clusters were taken into account. Comparison of the valence and the core-electron spectral structures showed that the formation of the inner (IVMO) and the outer (OVMO) valence molecular orbitals contributes to the spectral structure more than the many-body processes. The Ce 4f electrons were established to participate directly in chemical bond formation in CeO2 losing partially their f character. They were found to be localized mostly within the outer valence band. The Ce 5p atomic orbitals were shown to participate in the formation of both the inner and the outer valence molecular orbitals (MOs). A large part in the IVMO formation is taken by the filled Ce 5p1/2, 5p3/2 and O 2s atomic shells, while the Ce 5s electrons participate weakly in the chemical bond formation. The composition and the sequent order of the molecular orbitals in the binding energy range of 0 to ∼50 eV were established. A quantitative scheme for the molecular orbitals of CeO2 was built. This scheme is fundamental for understanding the nature of chemical bonding and also for the interpretation of other X-ray spectra of CeO2. Evaluations revealed that the IVMO electrons weaken the chemical bond formed by the OVMO electrons by 37%.The work was supported by the RFBR grant № 17-03-00277a. M.V. Ryzhkov acknowledges financial support of FASO of Russia ISSC of the Ural Branch of RAS № AAAA-A16-116122810214-9. A.J. Popel acknowledges funding from the UK EPSRC (grant EP/I036400/1) and Radioactive Waste Management Ltd (formerly the Radioactive Waste Management Directorate of the UK Nuclear Decommissioning Authority, contract NPO004411A-EPS02), a maintenance grant from the Russian Foundation for Basic Research (projects 13-03-90916) and CSAR bursary
Morphology and Function of Myocardium and Skin Microcirculation 24 Hours after Clozapine Poisoning
Aim of the study: to evaluate the effect of sublethal dose of clozapine on the rat cardiovascular system 24 hours after administration of the drug.Materials and methods. The experiments were carried out on 17 male Wistar rats weighing 220-270 g. Under general anesthesia with sevoflurane, the animals of Group I were enterally given 0.9% NaCl solution, Group II animals received clozapine in a dose of 150 mg/kg diluted in 2.0 ml of NaCl solution 0.9%, Group III animals were given clozapine in a dose of 150 mg/kg diluted in 2.0 ml of 40% ethanol. Blood pressure (BP), heart rate (HR), skin microcirculation using laser Doppler flowmetry (LDF), NADH and FAD+ fluorescence were estimated 24 hours after the drug administration. After euthanasia, autopsy with sampling of internal organs for morphological study was done. Then paraffin heart sections with subsequent H&E staining were made, which were studied using the Nikon Eclipse Ni-U light microscope.Results. Spectral analysis of local skin blood flow fluctuations showed that clozapine reduced Amax and amplitude in all frequency ranges of active microcirculation regulatory system in comparison with the controls. No differences in blood gases and acid-base status were seen between the groups of animals 24 hours after administration of the drugs. However, the animals from clozapine groups (II and III) had lower hemoglobin and hematocrit than in the control group.Histological examination of rat hearts in groups II and III revealed congested venules, haemorrhages by dia-pedeses, perivascular and interstitial edema. The signs of blood stasis and marginalization of granulocytes were noted in the vascular lumen. Irregular staining of myocardium due to cardiomyocytes with hypereosinophilic and occasionally homogeneous cytoplasm, fragmentation and deformations of cardiac cells were revealed. Car-diomyocytic nuclei were polymorphic and irregularly stained, and perinuclear edema was observed.Conclusions. The results of the study demonstrate the toxic effect of clozapine manifesting as progressive myocardial alteration and disordered central and peripheral circulation. However, control of bradycardia, restored skin perfusion and metabolic improvement (diagnosed by NADH fluorescence and blood acid-base status) after 24 hours may be due to the activation of compensatory mechanisms, particularly through changes in neurogenic and humoral regulation of homeostasis
Comparative assessment of the diagnostic value of echocardiography and magnetic resonance imaging in determining myocardial viability
Aim. To compare myocardial imaging methods in patients with complicated coronary artery disease with significantly decreased myocardial contractility.Material and methods. This single-center retrospective study included 109 patients with complicated coronary artery disease who underwent surgical treatment between 2014 and 2020. All patients had indications for delayed contrast-enhanced cardiac magnetic resonance imaging (MRI) in order to determine myocardial viability due to a pronounced decrease in left ventricular contractility according to echocardiography (ejection fraction (EF) ≤30%).Results. Impairment of local contractility according to MRI and echocardiography significantly correlates with depth of contrast accumulation (p=0,0000000018 and p=0,0000034, respectively). Delayed contrast-enhanced cardiac MRI with cine sequences allows to determine higher number of impaired contractility cases compared with echocardiography (p=0,000006).Conclusion. MRI with cine sequence allowed to determine higher number of impaired contractility cases compared with echocardiography. Delayed contrastenhanced MRI is a reliably more sensitive method than electrocardiography in detecting left ventricular scarring. The depth of contrast agent accumulation correlates with local contractility impairment detected by echocardiography and delayed contrast-enhanced cardiac MRI
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