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Publications (10 of 23) Show all publications
Burtseva, E., Sundhäll, M., Tossavainen, T. & Wall, P. (2024). Engineering Students’ Varying Motivation and Self-concept in Mathematics. International Journal of Engineering Education, 40(1), 97-107
Open this publication in new window or tab >>Engineering Students’ Varying Motivation and Self-concept in Mathematics
2024 (English)In: International Journal of Engineering Education, ISSN 0949-149X, Vol. 40, no 1, p. 97-107Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Tempus Publications, 2024
National Category
Educational Sciences Didactics
Research subject
Applied Mathematics; Mathematics and Science Education
Identifiers
urn:nbn:se:ltu:diva-104323 (URN)2-s2.0-85184384737 (Scopus ID)
Note

Validerad;2024;Nivå 2;2024-04-09 (hanlid)

Available from: 2024-03-04 Created: 2024-03-04 Last updated: 2025-02-18Bibliographically approved
Tossavainen, T. & Burtseva, E. (2024). Factors that influence engineering students' motivation to study mathematics. In: Vanda Santos; Isabel Cabrita; Luís Descalço; Margarida M. Pinheiro; Nuno Bastos; Paula Carvalho; Paula Oliveira; Teresa B. Neto (Ed.), 1st International Conference on Math Education and Technology 2023 (ICMET 2023): book of abstracts: . Paper presented at 1st International Conference on Math Education and Technology (ICMET 2023), University of Aveiro, Portugal, October 2-4, 2023 (pp. 49-50). Aveiro, Portugal: Universidade de Aveiro Editora
Open this publication in new window or tab >>Factors that influence engineering students' motivation to study mathematics
2024 (English)In: 1st International Conference on Math Education and Technology 2023 (ICMET 2023): book of abstracts / [ed] Vanda Santos; Isabel Cabrita; Luís Descalço; Margarida M. Pinheiro; Nuno Bastos; Paula Carvalho; Paula Oliveira; Teresa B. Neto, Aveiro, Portugal: Universidade de Aveiro Editora , 2024, p. 49-50Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Aveiro, Portugal: Universidade de Aveiro Editora, 2024
Keywords
engineering student, motivation, online education, feedback
National Category
Didactics Other Mathematics
Research subject
Mathematics and Science Education; Applied Mathematics
Identifiers
urn:nbn:se:ltu:diva-104691 (URN)
Conference
1st International Conference on Math Education and Technology (ICMET 2023), University of Aveiro, Portugal, October 2-4, 2023
Note

ISBN for host publication: 978-972-789-908-1;

Full text license: CC BY 4.0

Available from: 2024-03-20 Created: 2024-03-20 Last updated: 2025-01-16Bibliographically approved
Almqvist, A., Burtseva, E., Rajagopal, K. R. & Wall, P. (2024). On modeling flow between adjacent surfaces where the fluid is governed by implicit algebraic constitutive relations. Applications of Mathematics, 69(6), 725-746
Open this publication in new window or tab >>On modeling flow between adjacent surfaces where the fluid is governed by implicit algebraic constitutive relations
2024 (English)In: Applications of Mathematics, ISSN 0862-7940, E-ISSN 1572-9109, Vol. 69, no 6, p. 725-746Article in journal (Refereed) Published
Abstract [en]

We consider pressure-driven flow between adjacent surfaces, where the fluid is assumed to have constant density. The main novelty lies in using implicit algebraic constitutive relations to describe the fluid’s response to external stimuli, enabling the modeling of fluids whose responses cannot be accurately captured by conventional methods. When the implicit algebraic constitutive relations cannot be solved for the Cauchy stress in terms of the symmetric part of the velocity gradient, the traditional approach of inserting the expression for the Cauchy stress into the equation for the balance of linear momentum to derive the governing equation for the velocity becomes inapplicable. Instead, a non-standard system of first-order equations governs the flow. This system is highly complex, making it important to develop simplified models. Our primary contribution is the development of a framework for achieving this. Additionally, we apply our findings to a fluid that exhibits an S-shaped curve in the shear stress versus shear rate plot, as observed in some colloidal solutions.

Place, publisher, year, edition, pages
Institute of Mathematics, Czech Academy of Sciences, 2024
Keywords
implicit algebraic constitutive relation, flow between adjacent surfaces
National Category
Fluid Mechanics
Research subject
Machine Elements; Applied Mathematics
Identifiers
urn:nbn:se:ltu:diva-110923 (URN)10.21136/AM.2024.0131-24 (DOI)001359260700001 ()2-s2.0-85209679663 (Scopus ID)
Note

Validerad;2024;Nivå 2;2024-12-05 (joosat);

Full text license: CC BY 4.0;

Available from: 2024-12-02 Created: 2024-12-02 Last updated: 2025-02-09Bibliographically approved
Tossavainen, T. & Burtseva, E. (2024). The Perceived Value of Proving in Learning Engineering Mathematics and its Dependence on Motivation and Study Habits. Nordic Journal of STEM Education, 8(2), 45-59
Open this publication in new window or tab >>The Perceived Value of Proving in Learning Engineering Mathematics and its Dependence on Motivation and Study Habits
2024 (English)In: Nordic Journal of STEM Education, ISSN 2535-4574, Vol. 8, no 2, p. 45-59Article in journal (Refereed) Published
Abstract [en]

This study reports on engineering students (N=369) from two Swedish universities and focuses on their perceived value of proving in learning engineering mathematics and some factors that may explain the observed variation in the perceived value. Our findings show that there is no significant difference in the perceived value between female and male students. In general, proving is not highly valued, and students are not confident in their skills in proving, except for proving by mathematical induction. However, students’ motivation in mathematics correlates with the perceived value and certain study habits are more regular among those students who appreciate proving as a suitable method for learning mathematics. Examples of such study habits include actively communicating with mathematics course teachers and reading the course textbook both before and after lectures.

Place, publisher, year, edition, pages
NTNU Norwegian University of Science and Technology, 2024
National Category
Didactics Other Mathematics
Research subject
Mathematics and Science Education; Applied Mathematics
Identifiers
urn:nbn:se:ltu:diva-110600 (URN)10.5324/njsteme.v8i2.5070 (DOI)
Note

Validerad;2024;Nivå 1;2024-10-30 (sarsun);

Full text license: CC BY 4.0;

Available from: 2024-10-30 Created: 2024-10-30 Last updated: 2024-10-30Bibliographically approved
Burtseva, E. & Maligranda, L. (2023). A new result on boundedness of the Riesz potential in central Morrey–Orlicz spaces. Positivity (Dordrecht), 27(5), Article ID 62.
Open this publication in new window or tab >>A new result on boundedness of the Riesz potential in central Morrey–Orlicz spaces
2023 (English)In: Positivity (Dordrecht), ISSN 1385-1292, E-ISSN 1572-9281, Vol. 27, no 5, article id 62Article in journal (Refereed) Published
Abstract [en]

We improve our results on boundedness of the Riesz potential in the central Morrey–Orlicz spaces and the corresponding weak-type version. We also present two new properties of the central Morrey–Orlicz spaces: nontriviality and inclusion property.

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
Central Morrey–Orlicz spaces, Morrey–Orlicz spaces, Orlicz functions, Orlicz spaces, Riesz potential, Weak central Morrey–Orlicz spaces
National Category
Mathematical Analysis
Research subject
Applied Mathematics
Identifiers
urn:nbn:se:ltu:diva-101976 (URN)10.1007/s11117-023-01013-4 (DOI)001189059200001 ()2-s2.0-85173831486 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-11-14 (hanlid);

Funder: Poznan University of Technology (0213/SBAD/0118);

License full text: CC BY

Available from: 2023-10-31 Created: 2023-10-31 Last updated: 2024-11-20Bibliographically approved
Almqvist, A., Burtseva, E., Rajagopal, K. & Wall, P. (2023). On flow of power-law fluids between adjacent surfaces: Why is it possible to derive a Reynolds-type equation for pressure-driven flow, but not for shear-driven flow?. Applications in Engineering Science, 15, Article ID 100145.
Open this publication in new window or tab >>On flow of power-law fluids between adjacent surfaces: Why is it possible to derive a Reynolds-type equation for pressure-driven flow, but not for shear-driven flow?
2023 (English)In: Applications in Engineering Science, ISSN 2666-4968, Vol. 15, article id 100145Article in journal (Refereed) Published
Abstract [en]

Flows of incompressible Navier–Stokes (Newtonian) fluids between adjacent surfaces are encountered in numerous practical applications, such as seal leakage and bearing lubrication. In seals, the flow is primarily pressure-driven, whereas, in bearings, the dominating driving force is due to shear. The governing Navier–Stokes system of equations can be significantly simplified due to the small distance between the surfaces compared to their size. From the simplified system, it is possible to derive a single lower-dimensional equation, known as the Reynolds equation, which describes the pressure field. Once the pressure field is computed, it can be used to determine the velocity field. This computational algorithm is much simpler to implement than a direct numerical solution of the Navier–Stokes equations and is therefore widely employed by engineers. The primary objective of this article is to investigate the possibility of deriving a type of Reynolds equation also for non-Newtonian fluids, using the balance of linear momentum. By considering power-law fluids we demonstrate that it is not possible for shear-driven flows, whereas it is feasible for pressure-driven flows. Additionally, we demonstrate that in the full 3D model, a normal stress boundary condition at the inlet/outlet implies a Dirichlet condition for the pressure in the Reynolds equation associated with pressure-driven flow. Furthermore, we establish that a Dirichlet condition for the velocity at the inlet/outlet in the 3D model results in a Neumann condition for the pressure in the Reynolds equation.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Navier-Stokes equation, Reynolds equation, Poiseuille law, Lower-dimensional model, Power-law fluid, Non-Newtonian fluid
National Category
Mathematical Analysis
Research subject
Machine Elements; Applied Mathematics
Identifiers
urn:nbn:se:ltu:diva-102664 (URN)10.1016/j.apples.2023.100145 (DOI)001080276800001 ()2-s2.0-85169543467 (Scopus ID)
Funder
Swedish Research Council, DNR 2019-04293
Note

Validerad;2023;Nivå 2;2023-11-21 (joosat);

CC BY-NC-ND 4.0 License;

Available from: 2023-11-21 Created: 2023-11-21 Last updated: 2024-11-20Bibliographically approved
Almqvist, A., Burtseva, E., Rajagopal, K. & Wall, P. (2023). On lower-dimensional models of thin film flow, Part C: Derivation of a Reynolds type of equation for fluids with temperature and pressure dependent viscosity. Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, 237(3), 514-526
Open this publication in new window or tab >>On lower-dimensional models of thin film flow, Part C: Derivation of a Reynolds type of equation for fluids with temperature and pressure dependent viscosity
2023 (English)In: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 237, no 3, p. 514-526Article in journal (Refereed) Published
Abstract [en]

This paper constitutes the third part of a series of works on lower-dimensional models in lubrication. In Part A, it was shown that implicit constitutive theory must be used in the modelling of incompressible fluids with pressure-dependent viscosity and that it is not possible to obtain a lower-dimensional model for the pressure just by letting the film thickness go to zero, as in the proof of the classical Reynolds equation. In Part B, a new method for deriving lower-dimensional models of thin-film flow of fluids with pressure-dependent viscosity was presented. Here, in Part C, we also incorporate the energy equation so as to include fluids with both temperature and pressure dependent viscosity. By asymptotic analysis of this system, as the film thickness goes to zero, we derive a simplified model of the flow. We also carry out an asymptotic analysis of the boundary condition, in the case where the normal stress is specified on one part of the boundary and the velocity on the remaining part.

Place, publisher, year, edition, pages
Sage, 2023
Keywords
Reynolds equation, elastohydrodynamic lubrication (or EHL), implicit constitutive relations, lower-dimensional models, piezo-viscous fluids, thermal effects
National Category
Other Mechanical Engineering Mathematical Analysis
Research subject
Machine Elements; Applied Mathematics
Identifiers
urn:nbn:se:ltu:diva-94919 (URN)10.1177/13506501221135269 (DOI)000893930300001 ()2-s2.0-85144235739 (Scopus ID)
Funder
Swedish Research Council, DNR 2019-04293
Note

Validerad;2023;Nivå 2;2023-04-18 (joosat);

Licens fulltext: CC BY License

Available from: 2022-12-20 Created: 2022-12-20 Last updated: 2025-02-14Bibliographically approved
Burtseva, E., Maligranda, L. & Matsuoka, K. (2022). Boundedness of the Riesz potential in central Morrey-Orlicz spaces. Positivity (Dordrecht), 26(1), Article ID 22.
Open this publication in new window or tab >>Boundedness of the Riesz potential in central Morrey-Orlicz spaces
2022 (English)In: Positivity (Dordrecht), ISSN 1385-1292, E-ISSN 1572-9281, Vol. 26, no 1, article id 22Article in journal (Refereed) Published
Abstract [en]

Boundedness of the maximal operator and the Calderón–Zygmund singular integral operators in central Morrey–Orlicz spaces were proved in papers (Maligranda et al. in Colloq Math 138:165–181, 2015; Maligranda et al. in Tohoku Math J 72:235–259, 2020) by the second and third authors. The weak-type estimates have also been proven. Here we show boundedness of the Riesz potential in central Morrey–Orlicz spaces and the corresponding weak-type version. 

Place, publisher, year, edition, pages
Springer Nature, 2022
Keywords
Riesz potential, Orlicz functions, Orlicz spaces, Morrey–Orlicz spaces, Central Morrey–Orlicz spaces, Weak central Morrey–Orlicz spaces
National Category
Mathematical Analysis
Research subject
Applied Mathematics
Identifiers
urn:nbn:se:ltu:diva-81166 (URN)10.1007/s11117-022-00879-0 (DOI)000760272400005 ()2-s2.0-85125504493 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-03-22 (hanlid);

Funder: Japan Society for the Promotion of Science (17K05306, 20K03663)

Available from: 2020-10-16 Created: 2020-10-16 Last updated: 2022-07-04Bibliographically approved
Almqvist, A., Burtseva, E., Rajagopal, K. & Wall, P. (2021). On lower-dimensional models in lubrication, Part A: Common misinterpretations and incorrect usage of the Reynolds equation. Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, 235(8), 1692-1702
Open this publication in new window or tab >>On lower-dimensional models in lubrication, Part A: Common misinterpretations and incorrect usage of the Reynolds equation
2021 (English)In: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 235, no 8, p. 1692-1702Article in journal (Refereed) Published
Abstract [en]

Most of the problems in lubrication are studied within the context of Reynolds’ equation, which can be derived by writing the incompressible Navier-Stokes equation in a dimensionless form and neglecting terms which are small under the assumption that the lubricant film is very thin. Unfortunately, the Reynolds equation is often used even though the basic assumptions under which it is derived are not satisfied. One example is in the mathematical modelling of elastohydrodynamic lubrication (EHL). In the EHL regime, the pressure is so high that the viscosity changes by several orders of magnitude. This is taken into account by just replacing the constant viscosity in either the incompressible Navier-Stokes equation or the Reynolds equation by a viscosity-pressure relation. However, there are no available rigorous arguments which justify such an assumption. The main purpose of this two-part work is to investigate if such arguments exist or not. In Part A, we formulate a generalised form of the Navier-Stokes equation for piezo-viscous incompressible fluids. By dimensional analysis of this equation we, thereafter, show that it is not possible to obtain the Reynolds equation, where the constant viscosity is replaced with a viscosity-pressure relation, by just neglecting terms which are small under the assumption that the lubricant film is very thin. The reason is that the lone assumption that the fluid film is very thin is not enough to neglect the terms, in the generalised Navier-Stokes equation, which are related to the body forces and the inertia. However, we analysed the coefficients in front of these (remaining) terms and provided arguments for when they may be neglected. In Part B, we present an alternative method to derive a lower-dimensional model, which is based on asymptotic analysis of the generalised Navier-Stokes equation as the film thickness goes to zero.

Place, publisher, year, edition, pages
Sage Publications, 2021
Keywords
Reynolds equation, elastohydrodynamic (or EHL), implicit constitutive relations, lower-dimensional models, piezo-viscous fluids
National Category
Other Mechanical Engineering Mathematical Analysis
Research subject
Applied Mathematics; Machine Elements
Identifiers
urn:nbn:se:ltu:diva-81978 (URN)10.1177/1350650120973792 (DOI)000666594700016 ()2-s2.0-85097313267 (Scopus ID)
Funder
Swedish Research Council, 2019-04293
Note

Validerad;2021;Nivå 2;2021-07-05 (beamah)

Available from: 2020-12-14 Created: 2020-12-14 Last updated: 2025-02-14Bibliographically approved
Almqvist, A., Burtseva, E., Rajagopal, K. & Wall, P. (2021). On lower-dimensional models in lubrication, Part B: Derivation of a Reynolds type of equation for incompressible piezo-viscous fluids. Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, 235(8), 1703-1718
Open this publication in new window or tab >>On lower-dimensional models in lubrication, Part B: Derivation of a Reynolds type of equation for incompressible piezo-viscous fluids
2021 (English)In: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 235, no 8, p. 1703-1718Article in journal (Refereed) Published
Abstract [en]

The Reynolds equation is a lower-dimensional model for the pressure in a fluid confined between two adjacent surfaces that move relative to each other. It was originally derived under the assumption that the fluid is incompressible and has constant viscosity. In the existing literature, the lower-dimensional Reynolds equation is often employed as a model for the thin films, which lubricates interfaces in various machine components. For example, in the modelling of elastohydrodynamic lubrication (EHL) in gears and bearings, the pressure dependence of the viscosity is often considered by just replacing the constant viscosity in the Reynolds equation with a given viscosity-pressure relation. The arguments to justify this are heuristic, and in many cases, it is taken for granted that you can do so. This motivated us to make an attempt to formulate and present a rigorous derivation of a lower-dimensional model for the pressure when the fluid has pressure-dependent viscosity. The results of our study are presented in two parts. In Part A, we showed that for incompressible and piezo-viscous fluids it is not possible to obtain a lower-dimensional model for the pressure by just assuming that the film thickness is thin, as it is for incompressible fluids with constant viscosity. Here, in Part B, we present a method for deriving lower-dimensional models of thin-film flow, where the fluid has a pressure-dependent viscosity. The main idea is to rescale the generalised Navier-Stokes equation, which we obtained in Part A based on theory for implicit constitutive relations, so that we can pass to the limit as the film thickness goes to zero. If the scaling is correct, then the limit problem can be used as the dimensionally reduced model for the flow and it is possible to derive a type of Reynolds equation for the pressure.

Place, publisher, year, edition, pages
Sage Publications, 2021
Keywords
Reynolds equation, elastohydrodynamic (or EHL), implicit constitutive relations, lower-dimensional models, piezo-viscous fluids
National Category
Mathematical Analysis Other Mechanical Engineering
Research subject
Machine Elements; Applied Mathematics
Identifiers
urn:nbn:se:ltu:diva-81977 (URN)10.1177/1350650120973800 (DOI)000666594700017 ()2-s2.0-85097279613 (Scopus ID)
Funder
Swedish Research Council, 2019-04293
Note

Validerad;2021;Nivå 2;2021-07-05 (beamah)

Available from: 2020-12-14 Created: 2020-12-14 Last updated: 2025-02-14Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-1963-6829

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