61 research outputs found
Properties of Zirconia after Plasma Treatment
The influence of high-frequency plasma treatment on the properties of zirconia powder is shown in the work. The powder was produced by a plasma-chemical method. The powders had a foamy form with the size of agglomerates of 5-10 [mu]m and crystallites of 20-50 nm. The powders were treated by the pulse plasma unit with dielectric barrier discharge generator. It was shown that the plasma processing changes the acidity of water-powder suspensions from 8.1 to 4.3 pH, which signifies the powders' wettability improvement. It was revealed that more intensive mixing using ultrasound influences the acidity level, reducing it in comparison with mixing by paddle-type agitator. It was shown that these changes of surface properties have relaxation by 4% per day and extrapolation of this dependence shows that the powder will have initial properties after 400 hours storage at room conditions
Coherent Structures in the Near Field of Swirling Turbulent Jets and Flames Investigated by PIV and PLIF
The results of the experimental study of coherent flow structures in turbulent jets with different swirl rates are reported. The focus is placed on analysis of their impact on mixing of a passive scalar in the jets and on regular flame front deformations during combustion of fuel-lean and fuel-rich methane/air mixtures in case of a strongly swirling jet with vortex breakdown. The measurements are performed by applying simultaneously the particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF) techniques (acetone and HCHO for the nonreacting and reacting flows, respectively). The PIV data are processed by a proper orthogonal decomposition (POD), and the PLIF data are conditionally sampled according to the correlation coefficients of the velocity POD modes. The coherent velocity fluctuations are associated with regular patterns in the concentration fluctuation fields and flame front deformations. These patterns correspond to unsteady mixing by large-scale vortex structures in the outer mixing layer and also to variations of the entrainment rate for the flows with swirl
Investigation of the construction of airfield pavement using extruded polystyrene foam in the cold regions of the Russian Far East
The paper presents the results of scientific research and engineering calculations of rational designs parameters of airfield cover for cold regions of Russia using airstrip in Yuzhno-Sakhalinsk airport as the example. This airport is located in severe climatic and complex engineering-geological conditions. A deep seasonal freezing occurs everywhere. Applying extruded polystyrene plates in the structure construction makes it possible to significantly reduce frost heave and reduce foundation deformation. Performing numerical modeling of structures using «FEM models» geotechnical software complex allowed to quantify the processes of freezing and thawing in the annual cycle for the construction conditions. Based on the research results, designed constructive measures to ensure the operational reliability of the proposed rational engineering solutions for airstrips in the northern territories of the Russian Far East
ИССЛЕДОВАНИЯ ОБЪЕКТОВ КУЛЬТУРНОГО НАСЛЕДИЯ ФЕДЕРОЛЬНОГО ЗНАЧЕНИЯ
This article is supposed to make a professional analysis and assess the reliability of the historical buildings in Ryazan - an object of cultural heritage of federal importance “House of Saltykov-Shchedrin (Morozov) - 18th century”. On the basis of visual inspection and a large number of field studies using methods of ground-based laser scanning, photogrammetric method and other measuring instruments, areas of destruction and loss of the building were identified. According to the results of the analysis of archival documents and the processing of field work, a complex of architectural and archaeological measurement drawings was drawn up, on the basis of which further house restoration will be carried out without any damage to historical material. The article on a specific example provides brief archival information about the historical significance of the building, describes the methods and methods of the survey.Se supone que este artículo hace un análisis profesional y evalúa la confiabilidad de los edificios históricos en Ryazan, un objeto del patrimonio cultural de importancia federal "Casa de Saltykov-Shchedrin (Morozov) - Siglo XVIII". Sobre la base de la inspección visual y un gran número de estudios de campo que utilizan métodos de escaneo láser en tierra, el método fotogramétrico y otros instrumentos de medición, se identificaron áreas de destrucción y pérdida del edificio. De acuerdo con los resultados del análisis de documentos de archivo y el procesamiento del trabajo de campo, se diseñó un complejo de planos de mediciones arquitectónicas y arqueológicas, sobre la base de la cual se llevará a cabo una restauración adicional de la casa sin dañar el material histórico. El artículo sobre un ejemplo específico proporciona información breve de archivo sobre el significado histórico del edificio, describe los métodos y los métodos de la encuesta.В данной статье предполагается сделать профессиональный анализ и оценить надежность здания исторической застройки г. Рязани – объект культурного наследия федерального значения «Дом Салтыкова-Щедрина (Морозова)-XVIII в.». На основе визуального обследования и большого количества натурных исследований методами наземного лазерного сканирования, фотограмметрическим методом и другими измерительными приборами было выявлены участки разрушений и утраты здания. По результатам анализа архивных документов и обработки полевых работ стал комплекс архитектурно-археологических обмерных чертежей, на основе которого будет дальнейшая реставрация дома без какого-либо ущерба историческому материалу. В статье на конкретном примере приводятся краткие архивные сведения об исторической значимости здания, описаны методы и способы обследования
Isothermal modeling of aerodynamic structure of the swirling flow in a two-stage burner
The work deals with the experimental study of the aerodynamic structure of a swirling flow in the isothermal model of two-stage vortex combustion chamber. The main attention is focused on the process of flow mixing of two successively connected tangential swirlers of the first and second stages of the working section. Data on flow visualization are presented for two patterns of flow swirling. Time-averaged profiles of the axial and tangential velocity components are obtained with the help of laser-Doppler anemometer. In the case of flow co-swirling between two stages of the working section, instability of a secondary flow in the form of precessing vortex was distinguished. For the regime with counter flow swirling, effective mixing of the swirl flows was found; this was reflected by formation of the flow with uniform distribution of axial velocity over the cross-section
Vortex rope instabilities in a model of conical draft tube
We report on experimental studies of the formation of vortex ropes in a laboratory simplified model of hydroturbine draft tube. Work is focused on the observation of various flow patterns at the different rotational speed of turbine runner at fixed flow rate. The measurements involve high-speed visualization and pressure pulsations recordings. Draft tube wall pressure pulsations are registered by pressure transducer for different flow regimes. Vortex rope precession frequency were calculated using FFT transform. The experiments showed interesting features of precessing vortex rope like twin spiral and formation of vortex ring
Effect of omeprazole on patient-reported outcome measures in uninvestigated heartburn: a multi-country, multi-center observational study
Background: Heartburn occurs predominantly in the upper gastrointestinal tract and is associated with gastroesophageal reflux disease (GERD) and gastritis. Omeprazole is the most prescribed proton pump inhibitor class of medication to treat heartburn related clinical conditions. To compare the efficacy of omeprazole 40 mg (as a total daily dose) and 20 mg using patient-reported outcome measures (PROMs) in patients with heartburn due to various aetiologies like non-erosive reflux disease, GERD, gastritis, dyspepsia, functional heartburn, gastro-duodenal ulcer.Methods: Naïve patients presenting heartburn symptoms were treated with omeprazole. PROMs were assessed based on short-form-leeds dyspepsia questionnaires (SF-LDQ), work productivity activity impairment (WPAI), relief obtained using medication and, treatment satisfactory questionnaires (TSQ).Results: A total of 18,724 patients with heartburn (GERD and gastritis; n=10,509) were treated with omeprazole (Dr. Reddy’s omeprazole [DO]/generic omeprazole [GO]/branded omeprazole [BO]) 40 mg (as a total daily dose) and 20 mg. Statistical comparative analysis showed significant improvement with omeprazole 40 mg (as a total daily dose) compared to omeprazole 20 mg in SF-LDQ, relief obtained using medication among patients with heartburn. DO 20 mg showed a greater improvement under the ‘a lot’ and ‘complete’ relief category.Conclusions: Omeprazole 40 mg (as a total daily dose) presented better efficacy as compared to omeprazole 20 mg in patient reported outcomes. This study highlights omeprazole 40 mg as the preferred intervention for improving PROMs and quality of life in the treatment of heartburn related clinical conditions
The role of statins on helicobacter pylori eradication : Results from the european registry on the management of h. pylori (hp-eureg)
Funding: This project was promoted and funded by the European Helicobacter and Microbiota Study Group (EHMSG), the Spanish Association of Gastroenterology (AEG), and the Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd).Peer reviewedPublisher PD
Helicobacter pylori Diagnostic Tests Used in Europe : Results of over 34,000 Patients from the European Registry on Helicobacter pylori Management
Funding Information: This study was funded by Richen; however, clinical data were not accessible and the company was not involved in any stage of the Hp-EuReg study (design, data collection, statistical analysis, or manuscript writing). We want to thank Richen for their support. This project was promoted and funded by the European Helicobacter and Microbiota Study Group (EHMSG), the Spanish Association of Gastroenterology (AEG) and the Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd). The Hp-EuReg was co-funded by the European Union programme HORIZON (grant agreement number 101095359) and supported by the UK Research and Innovation (grant agreement number 10058099). The Hp-EuReg was co-funded by the European Union programme EU4Health (grant agreement number 101101252). Acknowledgments We want to especially thank Sylva-Astrik Torossian for her assistance in language editing. Natalia García Morales is the first author who is acting as the submission’s guarantor. All authors approved the final version of the manuscript.Peer reviewedPublisher PD
Wave flow of the evaporating liquid film
Nonlinear wave formation and heat transfer in a laminar falling liquid film in the presence of evaporation are studied numerically. The integral boundary layer model, modified with account of the phase change has been used to describe the wave motion. Numerical simulation of waves in a non isothermal film flow in the presence of evaporation Nonlinear wave formation and heat transfer in a laminar falling liquid film in the presence of evaporation are studied numerically. The integral boundary layer model, modified with account of the phase change has been used to describe the wave motion. Numerical simulation of waves in a non isothermal film flow in the presence of evaporation on an interface is carried out. It is shown that the natural waves caused by instability of flow occur on a surface of evaporating liquid film. For the first time the authors studied the evolution of excited waves in an evaporating film. It is shown that the forced waves occur on smaller distance, than natural ones. The amplitude of the developed waves drops with distance increase. Heat transfer wave intensification is mainly caused by decrease of a film thickness between peaks. Local Nusselt number is determined by distance between the peaks which increases at interaction and merging of some peaks. It is shown that the forced waves intensify essentially heat transfer within a certain range of frequencies in comparison with the naturally occurred waves
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