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Polymer and composite materials used in medicine – an overview

Oleksy Małgorzata, Dynarowicz Klaudia, Aebisher David

Polimery

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2023

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Vol. 68, nr 7-8

363--370

EN

The article is a review of the literature on the use of polymers in medicine as biomaterials. Examples of the preparation of the most commonly used synthetic polymers in medicine, such as: polylactide (PLA), polyglycolide (PGA), polyhydrobutyrate (PHB), polycaprolactone (PCL) are described. The characteristics of ceramic materials: hydroxyapatite (HAp) and tricalcium phosphate (TCP) are also presented in terms of the use of synthetic biodegradable polymers as biofillers. The last part of article is devoted to the functional properties of composites based on PLA with the addition of HAp and TCP.

PL

Artykuł stanowi przegląd literatury dotyczący zastosowania polimerów w medycynie jako biomateriałów. Opisano przykłady otrzymywania najczęściej stosowanych syntetycznych polimerów w medycynie takich jak: polilaktyd (PLA), poliglikolid (PGA), polihydromaślan (PHB), polikaprolakton (PCL). Przedstawiono także charakterystykę materiałów ceramicznych: hydroksyapatytu (HAp) i trójfosforanu wapnia (TCP) pod kontem stosowania jako bionapełniacze syntetycznych biodegradowalnych polimerów. Ostatnia część artykułu jest poświęcona właściwościom użytkowym kompozytów na osnowie PLA z dodatkiem HAp i TCP.

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Application of grey wolf optimizer to develop new global GMPE for estimating peak ground acceleration

Ghalehjough Babak Karimi, Agahian Saeid

Acta Geophysica

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2023

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Vol. 71, no. 5

2149--2161

EN

Ground motion prediction equations (GMPEs) are open challenge problems that have been developed since 1964. Parametric and nonparametric methods predict ground motion characteristics such as peak ground acceleration (PGA), velocity, displacements, and spectral accelerations. In the present study, the grey wolf optimization (GWO) algorithm was used to obtain a new and developed GMPE for predicting PGA. Data from recorded earthquakes from all over the world were collected, and after filtering of Mw and distance parameters, close to 2000 data were used for modelling. Three parameters of Mw (4–7.9), epicentral distance (0.25–115 km) and geological conditions (soft soil, stiff soil, rock) were used as input parameters for estimating PGA. Many previous studies classified geological conditions based on shear wave velocity at the top 30 m (Vs30), without taking into account the effect of Vs30 at each group. In this study, the effects of Vs30 were considered separately for each geological group too. Results showed that PGA decreased by increasing Vs30 and moving from soft soil toward rock. Finally, the relationship was compared with the other two relations suggested for the local region and global earthquakes, and despite the simplicity of the suggested relation gained by the GWO method, it estimated PGA in terms of accuracy to a good and acceptable level.

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Time dependent shake map for Uttarakhand Himalayas, India, using recorded earthquakes

Mittal Himanshu, Wu Yih-Min, Lin Ting-Li, Legendre Cédric P., Gupta Sushil, Yang Benjamin M.

Acta Geophysica

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2019

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Vol. 67, no. 3

753--763

EN

Uttarakhand Himalayas are highly sensitive to seismic hazard with possible occurrence of high-magnitude earthquakes. Fewer waveforms are available from previously recorded earthquakes, which are insufficient for carrying out seismic hazard studies. The recently installed strong motion instrumentation network (SMIN) in India, particularly, in Indian Himalayas is providing useful data. Using recorded data from SMIN, time-dependent peak ground acceleration and observed peak ground velocity shake maps are drawn for two earthquakes widely recorded by SMIN in Uttarakhand region of Indian Himalayan belt. Open-source Earthworm software with new algorithms is used for drawing these shake maps. The source mechanism is computed for April 4, 2011 earthquake using waveform inversion technique to relate it to the trend of shake maps. The computed focal mechanism shows one of the nodal planes in NW–SE, which are consistent with shake maps for the same earthquake. These time-dependent plotted shake maps provide useful information on the initial rupture, as well as the potential directivity of the rupture.

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A physics-based earthquake simulator and its application to seismic hazard assessment in Calabria (Southern Italy) region

Console R., Nardi A., Carluccio R., Murru M., Falcone G., Parsons T.

Acta Geophysica

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2017

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Vol. 65, no. 1

243--257

EN

The use of a newly developed earthquake simulator has allowed the production of catalogs lasting 100 kyr and containing more than 100,000 events of magnitudes ≥4.5. The model of the fault system upon which we applied the simulator code was obtained from the DISS 3.2.0 database, selecting all the faults that are recognized on the Calabria region, for a total of 22 fault segments. The application of our simulation algorithm provides typical features in time, space and magnitude behavior of the seismicity, which can be compared with those of the real observations. The results of the physics-based simulator algorithm were compared with those obtained by an alternative method using a slip-rate balanced technique. Finally, as an example of a possible use of synthetic catalogs, an attenuation law has been applied to all the events reported in the synthetic catalog for the production of maps showing the exceedance probability of given values of PGA on the territory under investigation.