scholarly journals Mechanical Properties of Grand Fir Wood Grown in the Czech Republic in Vertical and Horizontal Positions

BioResources ◽  
2014 ◽  
Vol 10 (1) ◽  
Author(s):  
Aleš Zeidler ◽  
Mohamed Zidan Mohamed Salem ◽  
Vlastimil Borůvka
2018 ◽  
Vol 276 ◽  
pp. 254-258
Author(s):  
Karel Mikulica ◽  
Dušan Dolák

In the current construction industry, great importance is given to the usage of thermally insulating building materials. One of the many such materials can be a cement foam or foam concrete, a mixture of cement mortar and technical foam. This material can be, due to its consistency right after mixing, applied to uneven horizontal surfaces where usage of conventional thermal board insulation materials would be complicated. This paper discusses the methodology of testing of the physical and mechanical properties of foaming additives such as strength, density, foaming number and half-separability of technical foams. Then this methodology was subsequently verified on the five commonly used foaming additives in the Czech Republic.


Author(s):  
Tomáš Kolář ◽  
Michal Rybníček

The paper deals with the examination of physical and mechanical properties of subfossil wood of oak (Quercus, sp.). The issue of establishing physical and mechanical properties of subfossil oak wood has not yet been addressed in the area of the Czech Republic. The main objective is to find out what changes to subfossil wood properties have occurred in comparison with recent wood. For these purposes, samples from three locations were taken (gravel pit Tovačov – district Přerov, gravel pit Kostomlátky – district Nymburk, and the Bečva basin near Osek nad Bečvou). All of the selected properties were tested in compliance with relevant valid Czech technical norms (ČSN). The results provide us with a realistic picture of the properties of wood that has been deposited under the ground in very specific conditions for thousands of years. With regard to density, the results do not show any definite changes. The dimensions of subfossil wood are approximately doubled in comparison with recent wood. On the other hand, there is an obvious decrease in mechanical properties. The paper also offers the results of dendrochronological or radiocarbon dating of the trunks.


2016 ◽  
Vol 827 ◽  
pp. 267-270 ◽  
Author(s):  
Magdaléna Šefflová ◽  
Tereza Pavlů

This paper is focused on the mechanical properties development of fine recycled aggregate (FRA) concrete. FRA was obtained from recycling plant in the Czech Republic. There were prepared four concrete mixtures in the laboratory. The first mixture was reference (REF) with fine natural aggregate (FNA). FNA was replaced in concrete mixtures R10, R20 and R30 in varying replacement ratio. The concrete mixtures R10, R20 and R30 contained 10 %, 20 % and 30 % FRA. There were tested properties of concrete. Finally, it is possible to say that the use of the FRA in concrete influences concrete properties. It is necessary to verify of probably an improvement of compressive strength of FRA concrete in future research. However, FRA concrete is possible to be used in the manufacturing of building structures, but it is necessary to test durability and lifespan of FRA concrete.


2021 ◽  
Vol 325 ◽  
pp. 188-193
Author(s):  
Lenka Nevřivová ◽  
David Zemánek

The development and subsequent production of these special kind of grog from raw materials available in the Czech Republic is one of the possibilities how to reduce income costs for the production of refractory materials with specific properties. The experimental work is focused on verifying the possibility of producing grog with increased alumina content from available raw materials. The raw materials are kaolins and claystones. To achieve a higher content of alumina in the grog, waste mullite dust is used. In order to improve the physical and mechanical properties of the grog, modifiers are used. Selected modifiers are expected to affect positively on the resulting density while maintaining the heat properties.


1998 ◽  
Vol 12 (1) ◽  
pp. 7-24 ◽  
Author(s):  
Koupilova ◽  
Vagero ◽  
Leon ◽  
Pikhart ◽  
Prikazsky ◽  
...  

GeroPsych ◽  
2012 ◽  
Vol 25 (3) ◽  
pp. 161-166
Author(s):  
Hana Stepankova ◽  
Eva Jarolimova ◽  
Eva Dragomirecka ◽  
Irena Sobotkova ◽  
Lenka Sulova ◽  
...  

This work provides an overview of psychology of aging and old age in the Czech Republic. Historical roots as well as recent activities are listed including clinical practice, cognitive rehabilitation, research, and the teaching of geropsychology.


2000 ◽  
Vol 5 (1) ◽  
pp. 62-65 ◽  
Author(s):  
Jiří Hoskovec ◽  
Josef M. Brožek

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