Spatially Continuous and Discontinuous Galerkin Finite Element Approximations for Dynamic Viscoelastic Problems

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonBrunel University Londo

Microfluidic Platforms for Evaluation of Nanobiomaterials: a Review

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Microfluidic Platforms for Evaluation of Nanobiomaterials: A Review

Biomaterials, especially those based on nanomaterials, have emerged as critical tools in biomedical applications. The applications encompass a wide range such as implantable devices, tissue regeneration, drug delivery, diagnostic systems, and molecular printing. The type of materials used also covers a wide range: metals (permanent and degradable), polymers (permanent and degradable), carbon nanotubes, and lipid nanoparticles. This paper explores the use of microfluidic platforms as a high-throughput research tool for the evaluation of nanobiomaterials. Typical screening of such materials involves cell/tissue cultures to determine attributes such as cell adhesion, proliferation, differentiation, as well as biocompatibility. In addition to this, other areas such as drug delivery and toxicity can also be evaluated via microfluidics. Traditional approach for screening of such materials is very time-consuming, and a lot of animals should be sacrificed since it involves one material and a single composition or concentration for a single test. The microfluidics approach has the advantage of using multiple types of drugs and their concentration gradients to simultaneously study the effect on the nanobiomaterial and its interaction with cell/tissue. In addition to this, microfluidics provides a unique environment to study the effect of cell-to-extracellular interaction and cell-to-cell communication in the presence of the nanobiomaterials

Financial Market Crash and Phase Transition: Through Model-Free Framework with Machine Learning

Recent studies have attempted to understand market crash using the concept of phase transition in statistical physics. This study finds certain behavior in the financial market such as the critical phenomena that occur during phase transition. We apply model-free framework using convolutional neural network methods instead of the complex mathematical models studied previously. The results show that the financial market crash has a similar behavior to the phase transition of particles. Furthermore, we find that the similar behavior between financial market crash and phase transition gives better understanding on the market crash and detecting it

Randomized Flexible GMRES with Deflated Restarting

International audienceFor high dimensional spaces, a randomized Gram-Schmidt (RGS) algorithm is beneficial in computational costs as well as numerical stability. We apply this dimension reduction technique by random sketching to Krylov subspace methods, e.g. to the generalized minimal residual method (GMRES). We propose a flexible variant of GMRES with the randomized Gram-Schmidt based Arnoldi iteration to produce a set of basis vectors of the Krylov subspace. Even though the Krylov basis is no longer l2 orthonormal, its random projection onto the low dimensional space shows l 2 orthogonality. As a result, it is observed the numerical stability which turns out to be independent of the dimension of the problem even in extreme scale problems. On the other hand, as the Harmonic Ritz values are commonly used in GMRES with deflated restarting to improve convergence, we consider another deflation strategy, for instance disregarding the singular vectors associated with the smallest singular values. We thus introduce a new algorithm of the randomized flexible GMRES with singular value decomposition (SVD) based deflated restarting. At the end, we carry out numerical experiments in the context of compressible turbulent flow simulations. Our proposed approach exhibits a quite competitive numerical behaviour to existing methods while reducing computational costs

Reactivity of Magnesium Metal for Biodegradable Medical Implants

This learning activity will provide an opportunity for students to develop their critical thinking and research skills in chemistry by asking them to investigate corrosion rates of metals and draw conclusions from their experiments. Students will measure corrosion rates in specific alloys and apply their findings to real world issues, such as medical implants. This module is intended for high school students. The document is available to download in PDF file format