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Degradation of mechanical properties of magnesium alloy
Sedláček, R.; Suchý, Tomáš; Padovec, Z.
2019 - English
In this study, biodegradation behaviour of WE43 magnesium alloy have been studied and compared during exposure to three different media commonly used to simulate the conditions of human body environment. Magnesium alloys emerged as a new class of bioresorbable implant materials. Their applications reduce certain risks associated with conventional permanent implants. Biodegradation behaviour of the WE43 magnesium alloy was observed under Dulbecco Modified Eagle Medium (DMEM, Sigma Aldrich) supplemented with 5 % fetal bovine serum and gentamicin antibiotic as standard. The samples were stored in the medium at 37 degrees C and in a 5 % CO2 atmosphere. The second type of medium was Hank's Salt Balanced Solution (HBSS, Sigma Aldrich), which simulates the inorganic composition of blood plasma. HBSS was tempered at 37 degrees C. The last solution was an acidic solution of HCl + NaCl (pH2) with pH similar to 2 (0.01M HCl and 0.14M NaCl) tempered at 37 degrees C. The acidic type of solution was used to simulate a local acidic environment associated with osteoclast activity during bone remodelling. Changes in the mechanical properties of the samples during exposure to simulated body conditions were observed.
Keywords:
Bioabsorbable metals; Biodegradation; Magnesium; Implant
Available at various institutes of the ASCR
Degradation of mechanical properties of magnesium alloy
In this study, biodegradation behaviour of WE43 magnesium alloy have been studied and compared during exposure to three different media commonly used to simulate the conditions of human body ...
Mechanical and structural properties of collagen nanofribrous layers under simulated body conditions
Říhová, J.; Suchý, Tomáš; Vištejnová, L.; Horný, L.; Šupová, Monika
2019 - English
The theme of this paper is the analysis of mechanical and structural properties of nanofibrous COL under simulated body conditions and in the presence of osteoblasts and dermal fibroblasts. COL were prepared by electrostatic spinning of 8 wt% collagen type I dispersion with 8 wt% (to COL) of PEG in phosphate buffer/ethanol solution (1/1 vol). The stability of COL was enhanced by means of cross-linking with EDC and NHS at a molar ratio of 4:1. COL were exposed in culture medium for 21 days and human SAOS-2 human dermal fibroblasts and osteoblasts were cultured therein for 21 days as well.
Keywords:
collagen; fibroblasts; osteoblasts; mechanical properties; structural properties; biodegradation
Available at various institutes of the ASCR
Mechanical and structural properties of collagen nanofribrous layers under simulated body conditions
The theme of this paper is the analysis of mechanical and structural properties of nanofibrous COL under simulated body conditions and in the presence of osteoblasts and dermal fibroblasts. COL were ...
Field measurement of natural electromagnetic emissions near the active tectonic and mass-movement fractures in caves
Trčka, T.; Macků, R.; Koktavý, P.; Škarvada, P.; Baroň, I.; Stemberk, Josef
2017 - English
Laboratory tests on a wide range of solid materials shoved that the electromagnetic emission (EME) signals are generated during the samples mechanical stress. EME anomalies have been observed also under natural conditions in association to fracture processes, tectonic loading, stress redistribution and crack propagation prior to earthquake or in relation to deep-seated gravitational mass movements. This paper describes a first prototype of the Emission data logger, which was specially developed for the continual EME monitoring in field conditions. Our equipment has been installed and tested in Obir Caves (Austria) at an active tectonic fault. The pilot long-term EME measurement results from this location are also presented in this paper.
Keywords:
Active tectonic fault; Continual monitoring; Emission data logger; Field measurement; Fracture processes; Natural electromagnetic emissions
Available at various institutes of the ASCR
Field measurement of natural electromagnetic emissions near the active tectonic and mass-movement fractures in caves
Laboratory tests on a wide range of solid materials shoved that the electromagnetic emission (EME) signals are generated during the samples mechanical stress. EME anomalies have been observed also ...
Chemické vlastnosti odpadních sádrovců z různých energetických zdrojů
Kroulíková, S.; Mercl, F.; Száková, J.; Perná, Ivana; Tlustoš, P.
2017 - Czech
V rámci studie byly porovnávány hodnoty pH, obsahy živin a vybraných rizikových prvků v sádrovcích ze čtyř významných energetických zdrojů v České republice. Zároveň byl hodnocen jejich potenciál pro zemědělské využití. Dle našich výsledků jsou odpadní sádrovce významným zdrojem síry 17,8 – 19,0 %) a vápníku (23,0 – 30,2 %) a mohou tak snížit nedostatek těchto živin v půdě. Nicméně u tří testovaných sádrovců byl stanoven nadlimitní obsah arsenu a rtuti. Pouze jeden sádrovec vyhověl legislativně a obsah všech hodnocených rizikových prvků byl pod limitními hodnotami. Nezbytné je tento materiál dále testovat v modelových i polních podmínkách a zhodnotit jeho využití v zemědělství jako levnější alternativu k běžným minerálním hnojivům se sírou.\n\n\n There were compared flue gas desulphurization gypsums (FGDGs) from four different power plants in the Czech Republic on chemical properties (pH, total content of nutrients and risk elements) and then was assessed their potential for utilization in agriculture as fertilizer without any risk to the environment. According to our results, the FGDGs represent an important possible source of sulphur (17.8 – 19.0 %) and calcium (23.0 – 30.2 %) for reduction of their deficit in the soil. However, contents of arsenic and of mercury in three of the tested FGDGs not fulfil the limit values for fertilizers. In the future, the remaining FGDG is thus necessary to evaluate for its fertilizing effects in model and field conditions.\n\n
Keywords:
nutrients; power plants; risk elements; soil reaction; sulphur
Available at various institutes of the ASCR
Chemické vlastnosti odpadních sádrovců z různých energetických zdrojů
V rámci studie byly porovnávány hodnoty pH, obsahy živin a vybraných rizikových prvků v sádrovcích ze čtyř významných energetických zdrojů v České republice. Zároveň byl hodnocen jejich potenciál pro ...
A COMPARISON OF THE CENTRIFUGAL FORCE SPINNING AND ELECTROSPINNING OF COLLAGEN UNDER DIFFERENT CONDITIONS
Hlavatá, J.; Suchý, Tomáš; Šupová, Monika; Pokorný, M.; Košťáková, E.
2017 - English
Collagen makes up one of the most important parts of the extracellular matrix and connective tissue. Collagen type I accounts for up to 90% of the collagen found in the body and it can be isolated and purified in large quantities and processed into a variety of forms. With respect to the process of the treatment of collagen into the nano-fibrous and submicron-fibrous forms, severe conditions leading to the denaturation of the collagen and thus the gelatin content should be avoided. Centrifugal force spinning and electrospinning processes appear to present promising methods for the spinning of collagen solutions. This paper deals with a comparison of the various methods applied in the processing of collagen, i.e. principally needle and needleless centrifugal spinning technology and electrospinning technology. In addition, the effect of process parameters and collagen solution conditions on the final form of the material was analyzed. Spun layers were prepared based on collagen type I isolated from calf skin. Nano-structured layers were prepared employing the spinning of 4-16 wt% collagen solutions in phosphate buffer saline and ethanol. The layers thus prepared were characterized by means of scanning electron microscopy and Fourier transform infrared spectroscopy.
Keywords:
collagen; electrospinning; centrifugal force spinning; triple-helix
Available at various institutes of the ASCR
A COMPARISON OF THE CENTRIFUGAL FORCE SPINNING AND ELECTROSPINNING OF COLLAGEN UNDER DIFFERENT CONDITIONS
Collagen makes up one of the most important parts of the extracellular matrix and connective tissue. Collagen type I accounts for up to 90% of the collagen found in the body and it can be isolated and ...
Rehabilitace strusky
Hanzlíček, T.; Perná, Ivana; Šupová, Monika
2017 - Czech
Příspěvek mapuje historické souvislosti vzniku haldy vysokopecní strusky na Kladně. Dále charakterizuje chemické a mineralogické složení a nabízí vysvětlení odlišného složení spodních aktivních a vrchních neaktivních vrstev. Bylo zjištěno, že pokud struska obsahuje aktivní složky ve formě neuspořádaných gehlenitických podílů, bude možné ji snadno přepracovat pomocí alkalické aktivace v hodnotnou, stabilní a ve vodě nerozpustnou hmotu. The paper describes the historical context of the heap of blast furnace slag in Kladno. It also characterizes the chemical and mineralogical composition and offers an explanation of the different composition of the bottom active and top inactive layers. It was found that if the slag contains active components in the form of a disordered gehlenites it can be easily reprocessed by alkaline activation into valuable, stable and water-insoluble matter.
Keywords:
Kladno; slag; construction material
Available at various institutes of the ASCR
Rehabilitace strusky
Příspěvek mapuje historické souvislosti vzniku haldy vysokopecní strusky na Kladně. Dále charakterizuje chemické a mineralogické složení a nabízí vysvětlení odlišného složení spodních aktivních a ...
Hydrogen charging of fuel cladding methodology
Krejčí, J.; Kabátová, J.; Kočí, J.; Weishauptová, Zuzana; Vrtílková, V.
2016 - English
Hydrogen content is a very important parameter for mechanical properties of fuel cladding. The methodology of developed hydrogen charging is described.
Keywords:
fuel cladding; hydridation
Available at various institutes of the ASCR
Hydrogen charging of fuel cladding methodology
Hydrogen content is a very important parameter for mechanical properties of fuel cladding. The methodology of developed hydrogen charging is described.
A brief introduction to the geology of the Moldanubian batholith
Verner, K.; René, Miloš; Žák, J.; Janoušek, V.
2015 - English
Emplacement processes and tectonic setting of the Moldanubian batholith. The batholith consists of multiple intrusive units (plutons, stocks and dykes), predominantly composed of granitic to granodioritic rocks with either S- or transitional I/S-type.
Keywords:
granite; petrology; geochemistry; Bohemian Massif
Available at various institutes of the ASCR
A brief introduction to the geology of the Moldanubian batholith
Emplacement processes and tectonic setting of the Moldanubian batholith. The batholith consists of multiple intrusive units (plutons, stocks and dykes), predominantly composed of granitic to ...
Origin of “rock cities”, pillars and cleft-conduits in kaolinite-bonded sandstone: New insight from study in sandstone quarry where landforms recently evolve
Bruthans, J.; Soukup, J.; Schweigstillová, Jana; Vaculíková, J.; Smutek, D.; Mayo, A. L.; Falteisek, L.
2013 - English
Based on measurements of relative erodibility, ambient and water-saturated tensile strength at natural and quarry exposures three distinct kinds of surfaces were distinguished (erodible sandstone, sub-vertical fracture surfaces and case hardened surfaces). Erosion proceeded along highly fractured zones.
Keywords:
case hardening erosion; fluidization; overland flow; piping; sandstone landforms
Available at various institutes of the ASCR
Origin of “rock cities”, pillars and cleft-conduits in kaolinite-bonded sandstone: New insight from study in sandstone quarry where landforms recently evolve
Based on measurements of relative erodibility, ambient and water-saturated tensile strength at natural and quarry exposures three distinct kinds of surfaces were distinguished (erodible sandstone, ...
Vysokotlaká adsorpce CO2 a CH4 na uhlí z hornoslezské pánve
Přibyl, Oldřich
2013 - Czech
Na třech vzorcích uhlí při 45°C byly změřeny vysokotlaké adsorpční izotermy CO2 a CH4. Byly stanoveny vzájemné sorpční poměry CO2 : CH4 ve výši kolem 1,75. Byl stanoven vliv maceráloveho složení na adsorpci výše uvedených plynů. High pressure adsorption isotherms of CO2 and CH4 were measured on three coal samples at 45 C temperature. The ratio of CO2:CH4 was determined to be around 1.75. The influence of coal maceral composition on gas adsorption was determined.
Keywords:
sorption; coal; Upper Silesian Basin
Available at various institutes of the ASCR
Vysokotlaká adsorpce CO2 a CH4 na uhlí z hornoslezské pánve
Na třech vzorcích uhlí při 45°C byly změřeny vysokotlaké adsorpční izotermy CO2 a CH4. Byly stanoveny vzájemné sorpční poměry CO2 : CH4 ve výši kolem 1,75. Byl stanoven vliv maceráloveho složení na ...
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