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1

Numerical optimization of the BAT-CELL Bio-Ambient-Tests method for engine exhausts toxicity evaluation

Kęska Aleksandra, Janicka Anna, Zawiślak Maciej

Combustion Engines

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2023

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R. 62, nr 1

19--25

EN

The BAT-CELL Bio-Ambient-Tests method is based on the assessment of the influence of the actual toxicity of various types of gas mixtures on living cells, taking into account the additive synergism. Work has been carried out on the application of the BAT-CELL method for testing engine exhaust gases. The application of computational fluid mechanics using Ansys Fluent made it possible to analyse the flow of engine exhaust gases through the aspiration system used, including analysis of shear stress values and their uniformity distribution on the bottom wall of the sampler containing cell culture on the bottom wall of the sampler. The appropriate flow rate of exhaust gases through the aspiration system and the shape of aspiration tubing for the sampler were selected in order to enable uniform contact of gas particles with the cell surface and not to damage them mechanically. The simulation results were verified in real-life tests and confirmed the theoretical assumptions.

2

Phenomenological evaluation of fatigue cracking of dental restorations under conditions of cyclic mechanical loads

Pieniak D., Niewczas A.M.

Acta of Bioengineering and Biomechanics

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2012

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Vol. 14, no. 2

9-17

EN

This paper deals with microcracks in dental filling material and hard tissues of the teeth treated conservatively. Human teeth, removed due to orthodontic or surgical reasons, were the subject of those research studies. The studies have been conducted in vitro with the application of mastication simulator. It has been indicated that the number of cracks and the degree of their expansion increase with the number of load cycles. The number of microcracks of the filling material on the masticating surface is lower than in the deeper layers; however, they are more extensive. After applying a specified long load series a progressive increase of microcracks in the restoration material and their expansion in the contact zone with the dentine have been observed. It has been demonstrated that on the masticating surface the number of microcracks and their expansion were proportional to the number of load cycles.

3

In vitro tests of dense hydroxyapatite materials

Sobczak A., Kida A., Kowalski Z., Wzorek Z.

Polish Journal of Chemical Technology

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2009

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Vol. 11, nr 1

44-49

EN

The paper presents the results of the calcining process of deproteinised and defatted bone pulp called bone sludge. The calcining process was performed in two stages. The first step of the calcining process was realized at the temperature of 600°C in a rotary kiln. In the second stage the obtained bone ashes were calcined at five different temperatures from 650°C to 950°C for 2 hours in a chamber kiln and in air atmosphere. The products of the calcining process were characterized by the XRD method. Calcium content was determined by titration whereas the contents of total phosphorus and acid-soluble phosphorus - by the spectrophotometric method. The X-ray analysis confirmed that hydroxyapatite is the main component of the calcining products. Calcium and phosphorus contents were kept at the level of 40% and 17.5%, respectively, which corresponded to the Ca/P ratio of not stechiometric hydroxyapatite. In vitro studies, in the simulated body fluid, Ringer liquid and distilled water were realised. The measurements of pH value of SBF and Ringer fluid were realized. Additionally electrical conductivity as well as pH for distilled water where conducted. The goal of these tests was to evaluate chemical durability of dense hydroxyapatite materials.

4

Optymalizacja geometrii oraz własności mechanicznych stentu wieńcowego ze stali Cr-Ni-Mo

Paszenda Z.

Inżynieria Biomateriałów

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2005

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R. 8, nr 45

5--11

PL

Prezentowana praca dotyczy problematyki optymalizacji cech geometrycznych oraz własności mechanicznych stentów wieńcowych wykonanych ze stali Cr-Ni-Mo. W pracy przedstawiono metodologię wyznaczania charakterystyki biomechanicznej układu stent-naczynie wieńcowe. Na jej podstawie dobrano własności mechaniczne stali, z której wykonano stenty. Weryfikację cech geometrycznych oraz własności mechanicznych stentów wieńcowych przeprowadzono na podstawie testów in vitro poprzez implantowanie ich do fantomu naczynia. Przeprowadzone testy potwierdziły prawidłowość doboru własności mechanicznych stali Cr-Ni-Mo, z której zostały wykonane stenty.

EN

Presented work concerns the issue of optimization of geometry and mechanical properties of coronary stents made of Cr-Ni-Mo steel. The methodology of determining the biomechanical characteristic of a stent - coronary vessel system was presented. The biomechanical characteristic, was the basis for the selection of mechanical properties of the stents were made of steel. The verification of geometrical features and mechanical properties of the coronary stents was carried out on the basis of in vitro tests by implantation of the stent into an artificial vessel. Tests confirmed the correct selection of the mechanical properties of the applied steel.

5

Analysis of the mechanical parameters of human brain aneurysm

Brigitta K. T., Raffai G., Bojtar I.

Acta of Bioengineering and Biomechanics

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2005

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Vol. 7, nr 1

3-22

EN

Cardiovascular disease is one of the most frequent reasons of mortality in the western word. Nowadays the mechanical properties of biological soft tissues were treated from a continuum mechanical perspective. The aim of this article is to investigate the mechanical response of arterial tissue. We present some three-dimensional finite element model to study the mechanical effects. The arterial wall is composed mainly of an isotropic matrix materiał (elastin) and collagen fibers from two families which are arranged in symmetncal spirals. These fibers induce the anisotropy in the materiał response. So the constitutive law of an artery is orthotropic. We want to develop a new constitutive law for arterial wall mechanics. In addition we make a comparative study of some material model used in the literature to describe the mechanical response of arteries. These are the following models: 1. Linearly elastic model. 2. Neo-Hookean model for incompressible materials. 3. Mooney-Rivlin model for incompressible materials. For this reason we make uniaxial and biaxial measurements to have appropriate parameters for the underlying material models. We investigate the biomechanical properties of strips from human cerebral aneurysms from surgery and cadavers. (An aneurysm is a bulge along a blood vessel.) Meridional and circumferential. thick and thin parts were distinguished respectively. This paper focuses on the analysis of the haemodynamic pattern and biophysical properties of cerebral aneurysms. diagnosed aiid delineated in living human individuals. The aim of this research is to estimate stresses at critical points of the aneurysm wall and its parent artery, and to estimate the likelihood of a later aneurysm rupture.

6

Wiodąca rola diagnostyki in vitro w europejskim systemie ochrony zdrowia

Odrowąż-Sypniewska G.

Laboratorium - Przegląd Ogólnopolski

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2003

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nr 4-5

44--46

PL

Badania diagnostyczne wykonywane w laboratorium stanowią integralną część postępowania lekarskiego i plasują się na czołowej pozycji w walce o poprawę stanu zdrowia społeczeństwa. Podstawowym celem diagnostyki laboratoryjnej jest dostarczenie lekarzowi danych o stanie zdrowia pacjenta w oparciu o badanie in vitro materiału biologicznego.