Cavitation Prediction and Avoidance in Design using Semi

LectureCavitation is a phenomenon that is of great concern to both the design and operation of pumps. The presence of cavitation – that is, the formation of vapor bubbles in the flowing fluid that subsequently collapses – can cause severe consequences from degradation of performance to damage mechanisms and even to catastrophic failure. Therefore, it is desired to predict under what conditions and design parameters cavitation occurs. Historically, the Net Positive Suction Head (NPSH) parameter and its various flavors (i.e. actual NPSH, available NPSH, required NPSH, 3% NPSH, etc.) have been used to characterize the pressure required at or near the pump inlet, to avoid the effects of cavitation. An important operational aspect of the required NPSH that is often ignored or perhaps unknown to many practitioners is that it is variable and depends on operational parameters, including rotor speed and fluid flow rate. The challenge is heightened in design, where geometry parameters also influence cavitation. The difficulty, at least in part, with cavitation is that the physical phenomenon of cavitation is separated from the effects of cavitation that are directly observable or measurable experimentally. That is, the physical phenomenon of cavitation occurs when local static pressure in a flow field drops below the vapor pressure of the fluid. However, influencing parameters, such as the presence of nucleation sites, the spatial and temporal extent of the local low pressure zone, the path of the flow field, and the wall boundaries all contribute effects that are not fully understood. Such dependencies are contributors to, for example, the observed cavitation damage seen in pump impellers that otherwise exhibit no cavitation related performance effects. This is also apparent in the cavitation characteristic often examined to evaluate the cavitation performance and required NPSH. The cavitation characteristic, a plot of the NPSH on the Abscissa and the total discharge head (TDH) on the ordinate, has historically been used to characterize cavitation because TDH can be directly measured experimentally. However, the location where cavitation damage can occur is usually several times the NPSH where measurable reduction in TDH occurs. 2 Copyright© 2021 by Turbomachinery Laboratory, Texas A&M Engineering Experiment Station In this work, the theoretical underpinnings that cause the physical phenomenon of cavitation are examined and used to develop a modern computational method using CFD of evaluating the cavitation characteristic from both a classical measurement perspective where TDH is affected, as well as the phenomenological perspective where vapor zone formation is tracked. This work shows that steady state RANS CFD, when combined with use of the Rayleigh-Plesset cavitation model, is able to effectively predict both onset of cavitation and the drop in TDH with computational expense that is order of magnitude less costly than the transient CFD methods that have previously been deployed on such problems Furthermore, it is shown in this work that effective design to avoid cavitation by accurate prediction of the semi-empirical required NPSH method first developed by Lomakin can be used directly in the design process. The implemented design process uses low-order and low computational cost numerical algorithms to solve the fluid flow and categorize many design candidates by parameters of interest, including the required NPSH. This work also enhances the semi-empirical Lomakin method for predicting cavitation with a modified correction for accounting for flow conditions of non-zero incidence. Under severe non-zero incidence conditions, there may exist one or more zones of local flow separation and low pressure region, or under mild incidence the flow may be attached but also is associated with local pressure in the flow field falling below the saturated vapor pressure, and this situation frequently occurs at most operating points away from the design condition. An attached sheet of cavitation bubbles can travel along the blade surface under certain conditions. It is shown that an empirically derived coefficient using the steady state CFD methodology previously discussed informs a fast reduced-order model that is accurate and can be utilized for quickly generating the NPSH maps of various potential design candidates and is therefore invaluable in pump design work

Specific features of modern multifunctional high-rise building construction

The article analyzes the main reasons for the development of high-rise building construction the most important of which-is a limitation of the urban areas and, consequently, the high price of land reserved for construction. New engineering and compositional solutions for the creation of new types of buildings are considered - complex technical designs of a large number of storeys completely meet the new requirements for safety and comfort. Some peculiarities of designing high-rise buildings and searching for optimal architectural and planning solutions are revealed since, with external architectural simplicity, high-rise buildings have complex structural and technological and space-planning solutions. We consider the specific features of a high-rise housing in various countries around the world, including Russia, such as the layout of the multi-storey residential buildings, depending on the climatic characteristics of the regions, assessment of the geological risk of the construction site, the choice of parameters and functional purpose of the sections of the territory of high-rise construction, location of the town-planning object for substantiating the overall dimensions of the building, assessment of changes aeration and engineering and hydrological conditions of the site. A special place in the article on the problems of improvement of the territory, the device of courtyards, landscaping, the device of playing and sports grounds. The main conclusion in the article is the following problem - when developing high-rise housing construction, the development of high-rise housing, and an increase in the population density in the territory of large cities of Russia, necessary to create a comfortable and safe level of residents living and not a decrease, but an improvement in the quality of the urban environment

Expression of fatty acid and triacylglycerol synthesis genes in interspecific hybrids of oil palm

© 2020, The Author(s). Evaluation of transcriptome data in combination with QTL information has been applied in many crops to study the expression of genes responsible for specific phenotypes. In oil palm, the mesocarp oil extracted from E. oleifera × E. guineensis interspecific hybrids is known to have lower palmitic acid (C16:0) content compared to pure African palms. The present study demonstrates the effectiveness of transcriptome data in revealing the expression profiles of genes in the fatty acid (FA) and triacylglycerol (TAG) biosynthesis processes in interspecific hybrids. The transcriptome assembly yielded 43,920 putative genes of which a large proportion were homologous to known genes in the public databases. Most of the genes encoding key enzymes involved in the FA and TAG synthesis pathways were identified. Of these, 27, including two candidate genes located within the QTL associated with C16:0 content, showed differential expression between developmental stages, populations and/or palms with contrasting C16:0 content. Further evaluation using quantitative real-time PCR revealed that differentially expressed patterns are generally consistent with those observed in the transcriptome data. Our results also suggest that different isoforms are likely to be responsible for some of the variation observed in FA composition of interspecific hybrids

Russian Students’ Readiness for Distance Learning: Current Situation and Future Challenges

Данная исследовательская статья посвящена вопросу владения студентами технологиями дистанционного обучения, актуальность которого резко возросла в условиях коронавирусной пандемии. Есть основания полагать, что и после ее преодоления высшая школа будет все более активно использовать эти технологии. Целью проведенного авторами исследования являлась оценка готовности студентов российских вузов к использованию технологий дистанционного обучения. В ходе анкетирования 428 студентов, обучающихся в вузах г. Ростова-на-Дону, были собраны сведения о развитии у опрошенных навыков использования интернет-технологий в сфере образования. Результаты исследования показали, что в предпандемический период необходимыми навыками для участия в видеоконференциях владели не более четверти студентов, навыками для самостоятельного освоения онлайн-курсов – около 16 %. Владение обеими технологиями, обеспечивающее эффективное дистанционное обучение, имело место лишь у 6,5 % респондентов. Полученные сведения о связи успеваемости с самостоятельным участием в онлайн-курсах, а также о соотношении этих показателей с общей цифровой грамотностью и погруженностью в социальные сети следует учитывать при широкой цифровой трансформации образования в условиях пандемии.In the context of the COVID pandemic, there has dramatically increased the significance of distance learning technologies. Higher education will most probably increase their usage even after overcoming the coronavirus. This paper aims at assessing Russian university students’ readiness to exercise distance learning technologies. The survey within Rostov-on-Don universities provided data on 428 students’ skills in using Internet technologies when studying. It is shown that in the pre-pandemic period, no more than a quarter of students had the necessary skills to participate in video conferences, and about 16 % of students took online courses autonomously. Only 6,5 % of the respondents could manage both technologies that comprise distance learning. The results obtained on the relationship between academic performance and self-participation in online courses, as well as on the relationship of these indicators with general digital literacy and immersion in social networks, should be taken into account within wide computerization of education during the pandemic.Работа выполнена при финансовой поддержке Министерства науки и высшего образования РФ в рамках Постановления № 218 «Создание высокотехнологичного производства программного комплекса для управления человеческим капиталом на основе нейротехнологий для предприятий высокотехнологичного сектора Российской Федерации» (шифр 2019-218-11-8185). Также авторы статьи выражают признательность Южному федеральному университету, предоставившему площадку для организации онлайн-анкетирования.The survey was financially supported by the Ministry of Science and Higher Education of the Russian Federation (Decree No. 218 «Creation of a High-Tech Production of a Software Package for Human Capital Management Based on Neurotechnologies for Enterprises of the High-Tech Sector of the Russian Federation», 2019-218-11-8185). The authors are also grateful to Southern Federal University for having provided facilities to organize an online survey

Thrombospondin-1 Is a Putative Target Gene of Runx2 and Runx3

Thrombospondin-1 (TSP-1), a matricellular protein widely acclaimed to be involved in the inhibition of angiogenesis and tumorigenesis, is synthesized and secreted by many cell types, including osteoblast and cancer cells. TSP-1 is highly upregulated during early stage of osteogenesis, whereas it inhibits terminal osteoblast differentiation. Expression of TSP-1 is downregulated in cancer cells, and its ectopic expression has been shown to restrain tumor growth. Transcriptional regulation of TSP-1 in osteogenesis and cancer is poorly understood; this prompted us to study its regulation by the two key regulators of the aforementioned processes: Runx2 and Runx3. Through a PCR-based cDNA subtraction technique, we identified and cloned a cDNA fragment for mouse TSP-1, whose expression was dramatically upregulated in response to Runx2 expression in mesenchymal stem cells. Moreover, TSP-1 expression was considerably reduced in the lung of Runx2 knockout mouse. On the other hand, TSP-1 gene expression drastically increased at both the transcriptional and translational levels in response to Runx3 expression in B16-F10 melanoma cells. In line with this, Runx2 and Runx3 bound to the TSP-1 promoter and stimulated its activity. Hence, these results provide first line of evidence that TSP-1 is a transcriptional target gene of Runx2 and Runx3

jsPsych-progno3

This is the data storage for jsPsych-progno3. The experiment id is: E_jC5wZWMavHR4wASg7Wuc5d

SOCIOLOGICAL PRIORITIES ANALYSIS OF THE HEALTHY LIFESTYLE PROMOTION POLICY

The fruitfulness of health interpretation in the aspect of culture and history is justified. The sociological information about the role of health as a factor of stratification, inequalities in health, economical and societal factors which influence health is analyzed. The interpretation schemes of a healthy lifestyle widely spread in mass consciousness and social discourse are critically considered. The appropriateness to distinguish aspects of complex understanding of a healthy lifestyle is justified: individual's quality of life, orientation towards health and social practices. It is shown that the promotion of individual-personal approach to health is supported by the competing service providers in the field of healthy lifestyles and does not require special support from the state. The task of the state is to provide the universal terms, legal regulation and standardization. Based on the analysis of the healthy lifestyle the priorities of the promotion policy of healthy lifestyle in modern Russian society are determined: informing about standards, integrating into the system of lifelong education, support and popularization of models meeting criteria of accessibility and collectivity