Subdomain BEM formulations for the solution of bio-heat problems in biological tissue with melanoma lesions

© 2017 Elsevier Ltd The main objective of the research presented in this paper is the development of efficient subdomain BEM solvers for the solution of steady-state and transient bio-heat problems in biological tissue, particularly involving melanoma of different sizes such as Clark II and IV. The short-term goal of the work is to investigate which of the numerical schemes implemented here produces the highest accuracy and efficiency, as a first step towards the long-term goal of solving inverse bio-heat problems for tumour diagnostics, i.e. the detection of tumour size and tumour parameters. The numerical results show that quadratic elements produce high accuracy with coarser meshes, and are thus more computationally efficient for this type of problem. It was also found that, for transient problems, a BEM formulation using the time-dependent fundamental solution of the diffusion equation was more efficient than the use of the fundamental solution of the Laplace equation with a finite difference time discretisation scheme, as much larger time steps could be used for the same accuracy. This work proposes that the subdomain BEM with quadratic elements and a time-dependent fundamental solution provides high accuracy and reduced computational time, and is thus indicated for the inverse analysis of bio-heat problems

High gradient magnetic particle separation in a channel with bifurcations

Micro particle separation from solid–liquid suspension under the influence of hydrodynamic and magnetic forces in a channel with bifurcation is studied numerically by applying the Boundary Element Method based fluid flow solver. The particle trajectories are computed using the Lagrangian particle tracking, where the forces on particles are computed based on the point particle representation. In the separator due to the bifurcation channel geometry the magnetic particles experience varying Kelvin force as they travel along the channel, although in the same direction the high gradient magnetic field does not change. In this way, the interplay of hydrodynamic and magnetic forces leads to changes in collection efficiency of the separator. A comparison with magnetic separation in the narrow channel design is done and recommendation for optimal choice of fluid flow rate and magnitude of external magnetic field is discussed

FORTIFICATIONS OF THE RAPALLO BORDER AND THEIR ROLE AS CO-CREATORS OF SPACE / RAPALLO SIENOS ĮTVIRTINIMAI IR JŲ VAIDMUO KURIANT ERDVĘ

In the period between the two world wars, the latent tensions between the European nations resulted in the construction of defensive positions on the borderlines of major European countries. Under the same conditions, the Italian Kingdom built an extensive fortification line, i.e. the Alpine Wall. The Kingdom of Serbs, Croats, and Slovenes (SHS) replied to it with the Rupnik Line. On the base of the Treaty of Rapallo, a 289-km long demarcation line was built with an exceptional defence infrastructure, which interfered with vast natural areas of exceptional quality that are protected by various nature conservation regimes today. The research presented in this paper is focused on a specific land expropriation. The goal is to understand the historical perspectives and assess the current significance of this fortification system with its impact on the natural environment. The system of spatial assessment of the architectural, urban, regional and spatial planning aspects and landscape interpretation has been developed with the use of spatial planning mapping and other methods. It was tested on the case study of the Žiri Municipality to establish a possible systemic base on which the entirety of the Rapallo border with its defence infrastructures could be mapped and their contemporary role assessed. Santrauka Tarpukario laikotarpiu užslėpta įtampa tarp Europos tautų lėmė gynybinių įtvirtinimų statybas tarp didžiųjų Europos šalių teritorijų. Tokiomis aplinkybėmis Italijos karalystė statė ilgą įtvirtinimų liniją, pavadintą Alpių siena. Jugoslavijos karalystė į tai atsakė Rupniko linijos statyba. Ji atsirado remiantis Rappallo sutartimi. Tai 289 km ilgio demarkacinė linija, nužymėta išskirtine gynybine struktūra, įsiterpusia į didžiulius natūralius ypatingos vertės plotus, šiuo metu saugomus įvairiais gamtos apsaugos reglamentais. Straipsnyje pateikiamas specifinio gamtos nusavinimo tyrimas. Pristačius istorinę raidą, siekiama nustatyti gynybinių įtvirtinimų dabartinę vertę ir jų poveikį gamtinei aplinkai. Aplinkos vertinimas architektūriniu, urbanistiniu, regioniniu ir erdvės planavimo aspektais ir kraštovaizdžio interpretavimas yra atliekamas taikant erdvės planavimo analizės žemėlapiuose ir kitus metodus. Tyrimas patikrintas Žiri savivaldybės atveju, sukūrus siūlomą sisteminę bazę, kurioje galima nužymėti Rappalo sieną su jos įtvirtinimais ir įvertinti jos šiuolaikinį vaidmenį. Reikšminiai žodžiai: Rappalo siena, Rappalo sutartis, Alpių siena, Rupniko linija, gynybiniai įtvirtinimai ir kraštovaizdis, paveldo interpretavimas, kartografijos metodas, Žiri savivaldybė, kultūros paveldo potencialas