Mathematical modeling of thermal stabilization of vertical wells on high performance computing systems

Temperature stabilization of oil and gas wells is used to ensure stability and prevent deformation of a subgrade estuary zone. In this work, we consider the numerical simulation of thermal stabilization using vertical seasonal freezing columns. A mathematical model of such problems is described by a time-dependent temperature equation with phase transitions from water to ice. The resulting equation is a standard nonlinear parabolic equation. Numerical implementation is based on the finite element method using the package Fenics. After standard purely implicit approximation in time and simple linearization, we obtain a system of linear algebraic equations. Because the size of freezing columns are substantially less than the size of the modeled area, we obtain mesh refinement near columns. Due to this, we get a large system of equations which are solved using high performance computing systems.Comment: 9 pages, 5 figure

How do students know they are right and how does one research it?

Although standards of rigor in mathematics are subject to debate among philosophers, mathematicians and educators, proof remains fundamental to mathematics and distinguishes mathematics from other sciences. There is no doubt that the ability to appreciate, understand and construct proofs is necessary for students at all levels, in particular for students in advanced undergraduate and graduate mathematics courses. However, studies show that learning and teaching proof may be problematic and students experience difficulties in mathematical reasoning and proving. This thesis is influenced by Lakatos’ (1976) view of mathematics as a ‘quasi-empirical’ science and the role of experimentation in mathematicians’ practice. The purpose of this thesis was to gain insight into undergraduate students’ ways of validating the results of their mathematical thinking. How do they know that they are right? While working on my research, I also faced methodological difficulties. In the thesis, I included my earliest experiences as a novice researcher in mathematics education and described the process of choosing, testing and adapting a theoretical framework for analyzing a set of MAST 217 (Introduction to Mathematical Thinking) students’ solutions of a problem involving investigation. The adjusted CPiMI (Cognitive Processes in Mathematical Investigation, Yeo, 2017) model allowed me to analyze students’ solutions and draw conclusions about the ways they solve the problem and justify their results. Also I placed the result of this study in the context of previous research

First Stages of Wet Wooden Ice-House Conservation Dated to the First Half of the 18th Century

In July 2019, during the restoration of the building of the First Cadet Corps (the former mansion of Aleksandr D. Menshikov), fragments of two structures that differ in the degree of preservation – a cellar and an ice-house (lednik), dating back to the first half of the 18th century, were discovered. The lednik is a traditional building for the North-Western region of Russia and a rare wooden architectural object for St. Petersburg of that time. In order to prepare the construction for dismantling and to plan its further restoration, preliminary studies were conducted. It was found that details from other wooden objects, probably ships and barges, were used for this construction. The physical parameters of the wood of the structural parts varied. Most parts of the lednik are waterlogged. Based on the results of the research, a plan was worked out for the preservation of this unique historical architectural object

The barycentric model of determining the sustainable growth determinants

The authors investigate the issue of modelling the balance of sustainable growth determinants based on determining the center of mass. They have identified the most relevant factors that characterize countries' social, economic, and political spheres, digital capability, and cybersecurity to determine sustainable development and growth. The research has been carried out based on empirical values of the selected 17 indicators for 127 world countries in 2018. As a result, the four–pole barycentric models were built as quadrangles, the vertices of which are composite targets formed by the determinants of the four spheres. The models' calculations were carried out taking into account three components: the values of the composite targets (as a geometric mean), the level of pairs balance (as the sum of opposite pairs of quadrilateral angles), and all four targets (as the distance between the actual and standard value of the center of mass). According to the analysis result of the first component, developed countries have the most effective targets (top five – Switzerland, Denmark, Norway, Finland, and the Netherlands). Research of the results of the second component has revealed an imbalance in target pairs for most countries. Determinants of socio–political development are the most effective for developed countries. The economic sphere is most unbalanced for the least developed countries. Various determinants can cause an imbalance for developing and new industrial countries. The analysis of the center of mass distances revealed that not only developed countries could be balanced, but also developing, new industrial and the least developed, which indicates a balanced development of their determinants, which is pretty slow. New Zealand, Mauritius, South Africa and Mali were the most balanced in each country's sustainable growth group

Correlation between Antioxidant Enzymes Activity and Intraerythrocyte Concentration of Fe, Mg, Zn, Cu in Pulmonary Arterial Hypertension and Cor Pulmonale in Children with Congenital Lung Disease and Cystic Fibrosis

Significant changes in the levels of the potential prooxidant Cu (increase) and the antioxidant Zn (decrease) in plasma were revealed in children having bronchopulmonary dysplasia (BPD) complicated by pulmonary arterial hypertension (PAH) and chronic cor pulmonale (CCP) when compared with the control. The Zn / Cu ratio in the blood plasma of patients with BPD, especially in CCP, was found to be lower than in the control group (p<0.001). This could indicate the activation of the prooxidant processes; simultaneously, the total antioxidant status (AOS) decreased. No significant increase in the intracellular free (“ionized” (i)) form of magnesium (iMg) was found; in fact, the concentration of iFe in all the patient groups was higher than in the control. An increase in the iCu and iZn levels (nonprotein-bound) was observed in the blood cells of the affected children. A significant increase in the glutathione peroxidase activity in the CCP patients may indicate an accumulation of organic peroxides, and partially compensate for the lesser activity of superoxide dismutase (SOD) and other antioxidants. The Zn / Cu and iZn/ iCu ratios were reduced in patients with CCP when compared with patients with PD without CCP

Comparison of Russian and Finnish educational systems at university level. : Education in the field of HVAC.

The subject of the project was comparison of Russian and Finnish educational systems of higher education in the field of HVAC. The system of higher education in Russia is represented by federal, municipal, and private universities and institutions. Higher education in Finland is provided by special institutions, vocational institutions, polytechnics, and universities. The thesis presents literature review of various sources like books, reports, and various Internet sources. These sources helped me to find information about Finnish and Russian educational legislation and about Finnish Polytechnics and Russian technical universities which provide education in the field of HVAC. Some dissimilarities between educational systems of two countries can be seen in the thesis. There are definitions for example in the duration of study and studied topics. Also the contents of Finnish and Russian of the Bachelor’s thesis are quite different. Russian thesis includes from 60 to 100 pages of practical calculations and 10 sheets of drawings. And in Finland thesis contains a lot of scientific work and investigations. One of the principal parts of the thesis is making questionnaires for Finnish and Russian teachers and students for getting information about the real present HVAC education. And the last source of information of this thesis was own experience of Russian students who have learned for several years in Russian technical universities and then they have come to study in the Finnish Polytechnic for one year

Analyzing Nabokvo\u27s Rendering of Metalanguage and Phonaesthesia in the Gift and Dar

The purpose of this research is to analyze Nabokov’s metalanguage and phonaesthesia as well as the rendering dynamics of Nabokov’s bilingual style. In this research, I incorporate three methods of analysis: philological, formalist, and comparative. In chapter one, I describe Leo Spitzer’s—a renowned linguist, philologist, and a literary critic—philological approach combined with historical analysis based on the example of lexemes conundrum and quandary. During the research, I also implement his method on the Russian lexeme калиберда/kaliberda, which likely possesses the same semantic correlation to the above verbal units. In chapters two, I provide the overview on the development of translation theory as a serious discipline and present its major taxonomizers in translation methods. In chapter three, I present Vladimir Nabokov’s aesthetics of rendering, literal translation, and its role in the discourse of translation theory. In chapter four, I analyze Nabokov’s phonaesthesia—alliteration, assonance, and consonance—and Nabokov’s usage of braided alliterative patterns in his poems and prose in Dar and The Gift. In addition, I analyze Russianisms, lexemes related closely to the Russian cultural context, and their translation in The Gift. I include my observations and conclusions on the analysis of metalanguage and phonaesthesia of Nabokov’s prose in Dar and The Gift in the last subchapter. In Dar and The Gift, Nabokov braids alliterative patterns within lexemes and structurally enabling the metalanguage with energy and deepening its contextual frames