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2. Application of a meshless space-time adaptive approach to phase-field modelling of polycrystalline solidificationTadej Dobravec, Boštjan Mavrič, Božidar Šarler, 2023, objavljeni znanstveni prispevek na konferenci Povzetek: We have developed a 2-D numerical meshless adaptive approach for phase-field modelling of dendritic solidification. The quadtree-based approach decomposes the computational domain into quadtree sub-domains of different sizes. The algorithm generates uniformly-distributed computational nodes in each quadtree sub-domain. We apply the meshless radial basis function generated finite difference method and the forward Euler scheme to discretise governing equations in each computational node. The fixed ratio between the characteristic size and the node spacing of a quadtree sub-domain ensures space adaptivity. The adaptive time-stepping accelerates the calculations further. In the framework of previous research studies, we used the approach to solve quantitative phase-field models for single dendrite growth in pure melts and dilute binary alloys. In the present study, we upgrade the solution procedure for the modelling growth of multiple differently oriented dendrites. Along with the space-time adaptive approach, we apply non-linear preconditioning of the phase-field equation to increase computational efficiency. We investigate a novel numerical approach's accuracy and computational efficiency by simulating the equiaxed dendrite growth from a dilute binary alloy.
Ključne besede: dendritic growth, phase-field method, meshless methods, polycrystalline solidification
Objavljeno v DiRROS: 21.03.2024; Ogledov: 99; Prenosov: 54
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3. Influence of surgical treatment and radiotherapy of the advanced intraoral cancers on complete blood count, body mass index, liver enzymes and leukocyte CD64 expressionTadej Dovšak, Alojz Ihan, Vojislav Didanovič, Andrej Kansky, Nataša Ihan Hren, 2009, izvirni znanstveni članek Povzetek: Background. The aim of our study was to evaluate the influence of the surgery and radiotherapy of the advanced oral squamous cell carcinoma on the complete blood count, body mass index (BMI), acute inflam-matory response, liver enzymes and expression of the CD64 index on leukocytes in the peripheral blood. Patients and method. Venous blood was obtained from 16 patients with advanced oral squamous cell carcinomas treated with radical surgery and external beam radiotherapy. Blood samples were collected prior to surgery (T1), after surgery (T2) and after radiotherapy (T3). Blood samples were analyzed for whole blood count, immunoglobulin G levels, liver enzymes (transaminases (ALT and AST) and gammaglutamyl trasferase (?-GT)), inflammatory response markers (C-reactive protein, erythrocyte sedimentation rate, albumin, white blood count, leukocyte count and CD64 expression on leukocytes). Assessment of nutrition was done by calculating the body mass index.Results. Surgery caused anaemia, trombocytosis, leukocytosis, lymphopenia, rise in acute phase proteins, elevation of CD64 expression on monocytes and neutrophyls, elevation of liver transaminases and lowering of ?-GT, albumin, protein and bilirubin levels. After radiotherapy haemoglobin, leukocytes, C-reactive protein, erythrocyte sedimentation rate, liver transferases, albumin, bilirubin and proteins returned almost to T1 levels, levels of lymphocytes, ?-GT and body mass index lowered. IgG levels remained almost unchanged at T2 and T3. Levels of the CD64 expression on monocytes and neutrophyls also elevated after radiotherapy.Conclusions. Surgery caused a significantly larger acute phase response than radiotherapy, while radiotherapy worsened the already present lymphopenia.
Objavljeno v DiRROS: 08.03.2024; Ogledov: 118; Prenosov: 30
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5. A coupled domain–boundary type meshless method for phase-field modelling of dendritic solidification with the fluid flowTadej Dobravec, Boštjan Mavrič, Rizwan Zahoor, Božidar Šarler, 2023, izvirni znanstveni članek Povzetek: Purpose - This study aims to simulate the dendritic growth in Stokes flow by iteratively coupling a domain and boundary type meshless method. Design/methodology/approach - A preconditioned phase-field model for dendritic solidification of a pure supercooled melt is solved by the strong-form space-time adaptive approach based on dynamic quadtree domain decomposition. The domain-type space discretisation relies on monomial augmented polyharmonic splines interpolation. The forward Euler scheme is used for time evolution. The boundary-type meshless method solves the Stokes flow around the dendrite based on the collocation of the moving and fixed flow boundaries with the regularised Stokes flow fundamental solution. Both approaches are iteratively coupled at the moving solid–liquid interface. The solution procedure ensures computationally efficient and accurate calculations. The novel approach is numerically implemented for a 2D case. Findings - The solution procedure reflects the advantages of both meshless methods. Domain one is not sensitive to the dendrite orientation and boundary one reduces the dimensionality of the flow field solution. The procedure results agree well with the reference results obtained by the classical numerical methods. Directions for selecting the appropriate free parameters which yield the highest accuracy and computational efficiency are presented. Originality/value - A combination of boundary- and domain-type meshless methods is used to simulate dendritic solidification with the influence of fluid flow efficiently.
Ključne besede: dendritic solidification, Stokes flow, phase-field method, space-time adaptivity, meshless methods, RBF-FD, modified method of regularised sources
Objavljeno v DiRROS: 07.02.2024; Ogledov: 144; Prenosov: 62
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6. Evaluation of silicona microstrip detectors as X-ray sensors in digital mammographyTadej Mali, Vladimir Cindro, Marko Mikuž, Urban Zdešar, Breda Jančar, 1999, izvirni znanstveni članek Povzetek: Background. Position sensitive silicon microstrip detectors are used as sensors for X rays in a digital imaging system. Silicon detectors were used inan edgeon geometry, yielding high X ray detection efficiency. Material and methods. A small detector system was assembled and tested. Images of a standard, 5 cm thick phantom were made and evaluated. It is demonstrated, thatthe use of silicon detectors in mammography could significantly contributeto a reduction of dose. All images were made with skin entrance doses lower than 1 mGy. Results and conclusion. Microcalcifications with a diameter of 350microm could still be detected with skin entrance doses of about 0.25 mGy. It was demonstrated that a 5 Ip/mm pattern can be detected. Image processing should further improve the image quality.
Objavljeno v DiRROS: 22.01.2024; Ogledov: 219; Prenosov: 39
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8. Study of blood perfusion with patent blue staining method in LPB fibrosarcoma tumors in immuno-competent and immuno-deficient mice after electrotherapy by direct currentTomaž Jarm, Dong Jian An, Jean Belehradek, Lluis M. Mir, Gregor Serša, Maja Čemažar, Tadej Kotnik, Jani Pušenjak, Damijan Miklavčič, 1997, izvirni znanstveni članek Objavljeno v DiRROS: 16.01.2024; Ogledov: 140; Prenosov: 32
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10. Winning combination of Cu and Fe oxide clusters with an alumina support for low-temperature catalytic oxidation of volatile organic compoundsTadej Žumbar, Iztok Arčon, Petar Djinović, Giuliana Aquilanti, Alenka Ristić, Goran Dražić, Janez Volavšek, Gregor Mali, Margarita Popova, Nataša Zabukovec Logar, Nataša Novak Tušar, Albin Pintar, Gregor Žerjav, 2023, izvirni znanstveni članek Objavljeno v DiRROS: 23.06.2023; Ogledov: 450; Prenosov: 188
Celotno besedilo (2,20 MB)
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