scholarly journals The effect of growth conditions in specific areas of Croatia and the Czech Republic on the physical and mechanical properties of black alder wood (Alnus glutinosa Gaertn.)

2016 ◽  
Vol 40 ◽  
pp. 7-12
Author(s):  
Jaromír MILCH ◽  
Hanuš VAVRCİK ◽  
Jan TIPPNER ◽  
Martin BRABEC
Keyword(s):  
Mechanical Properties ◽  
Czech Republic ◽  
Physical And Mechanical Properties ◽  
Alnus Glutinosa ◽  
Growth Conditions ◽  
The Czech Republic ◽  
Black Alder

Testing and Optimization of Production of Technical Foam for the Production of Cement Foam

2018 ◽  
Vol 276 ◽  
pp. 254-258
Author(s):  
Karel Mikulica ◽  
Dušan Dolák
Keyword(s):  
Mechanical Properties ◽  
Czech Republic ◽  
Construction Industry ◽  
Building Materials ◽  
Cement Mortar ◽  
Physical And Mechanical Properties ◽  
Foam Concrete ◽  
The Czech Republic ◽  
Insulation Materials ◽  
The Many

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.

scholarly journals Physical and mechanical properties of subfossil oak (Quercus, sp.) wood

2010 ◽  
Vol 58 (4) ◽  
pp. 123-134 ◽  
Author(s):  
Tomáš Kolář ◽  
Michal Rybníček
Keyword(s):  
Mechanical Properties ◽  
Czech Republic ◽  
Radiocarbon Dating ◽  
Physical And Mechanical Properties ◽  
Wood Properties ◽  
The Other ◽  
The Czech Republic ◽  
Oak Wood ◽  
Gravel Pit ◽  
Subfossil Wood

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.

Analysis of Alkali Oxides Influence on the Microstructure of Refractory Grog

2021 ◽  
Vol 325 ◽  
pp. 188-193
Author(s):  
Lenka Nevřivová ◽  
David Zemánek
Keyword(s):  
Mechanical Properties ◽  
Czech Republic ◽  
Experimental Work ◽  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Special Kind ◽  
Alumina Content ◽  
Refractory Materials ◽  
The Czech Republic ◽  
Alkali Oxides

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.

scholarly journals Selected physical and mechanical properties of Scots pine (Pinus sylvestris L.) wood from stands of younger age classes as criteria for rational utilization of timber

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Przemysław Marcin Pikiński ◽  
Jaroslav Szaban ◽  
Gerda Šilingienė ◽  
Robert Korzeniewicz ◽  
Witold Pazdrowski
Keyword(s):  
Mechanical Properties ◽  
Pinus Sylvestris ◽  
Scots Pine ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Growth Conditions ◽  
Tree Age ◽  
Coniferous Forests ◽  
Forest Site ◽  
Quality Coefficient

The aim of this study was to assess the quality of Scots pine (Pinus sylvestris L.) wood depending on the age of trees, forest site conditions and social class of tree position in the stand. Analyses were based on the determination of specific density and static bending strength, as well as the strength quality coefficient. It was to determine changes in physical and mechanical properties of timber depending on tree age as well as growth conditions reflected in the forest site such as fresh mixed coniferous forests and fresh mixed broadleaved forests. Experimental plots were established in 6 localities with 30, 40 and 60-year-old trees. In each of the stands, a 1-hectare experimental plot was established. Based on the measured DBH and tree height, dimensions of three mean sample trees were calculated, while the classification of social class of tree position in the stand developed by Kraft (1884) was also applied. Analyses were conducted on wood samples with 12% moisture content. Strength tests on wood samples were performed on an Instron 33RH204 universal strength testing machine. A detailed analysis showed properties of pine wood are improved with an increase of tree age in both forest sites. Statistically significant differences were observed for wood density and static bending strength. More advantageous properties were observed for wood of pines from the less fertile forest site, i.e., fresh mixed coniferous forests. Density and static bending strength were markedly determined by tree age and growth conditions. The static bending strength quality coefficient from pines growing in the fresh mixed coniferous forests increased between 30 and 40 years, similarly as it was for the fresh mixed broadleaved forests, while between 40 and 60 years, it deteriorated for the fresh mixed coniferous forests. Wood density from the fresh mixed coniferous forests was by 3% to 7% greater than pines growing in fresh mixed broadleaved forests. In turn, static bending strength of wood from pines growing in fresh mixed coniferous forests was by 4% to 10% greater than trees from the fresh mixed broadleaved forests.  Keywords: Scots pine, wood properties, forest site, Poland

scholarly journals Identification of Phytophthora alni subspecies in riparian stands in the Czech Republic

2013 ◽  
Vol 49 (Special Issue) ◽  
pp. S3-S10 ◽  
Author(s):  
P. Štěpánková ◽  
K. Černý ◽  
V. Strnadová ◽  
P. Hanáček ◽  
M. Tomšovský
Keyword(s):  
Czech Republic ◽  
Alnus Glutinosa ◽  
Pcr Primers ◽  
The Czech Republic ◽  
Specific Pcr ◽  
Related Taxon ◽  
Allele Specific ◽  
Allele Specific Pcr ◽  
Subspecific Level

In the Czech Republic, Phytophthora alni was first confirmed in 2001 and the pathogen has been quickly spreading and occupying almost the whole area of the country. The pathogen attacks Alnus glutinosa or A. incana to a lesser extent and causes considerable losses of alder trees along hundreds of kilometres of riverbanks. The aim of our work was to perform the identification of P. alni isolates at the subspecific level using PCR and to determine the frequencies and distribution of particular subspecies. The allele-specific PCR primers focused on allele diversity of orthologs of ASF-like, TRP1, RAS-Ypt, and GPA1 genes were selected for identification. Eighty-eight per cent of the 59 analysed isolates belonged to P. alni ssp. alni while 12% were P. alni ssp. uniformis. P. alni ssp. multiformis has not been recorded in the country till now. The two subspecies differed in distribution. P. alni ssp. alni dominated in riparian stands along broader rivers in lowlands and the results confirmed the more effective spreading of P. alni ssp. alni based on its higher aggressiveness and ecological advantage. P. alni ssp. uniformis was acquired rather from riparian stands of small watercourses at higher altitudes. The insular distribution of P. alni ssp. uniformis may represent the remains of its former occurrence. Therefore, P. alni ssp. uniformis may be an indigenous subspecies suppressed by the more aggressive related taxon.

scholarly journals Study of natural hybridization between Alnus incana (L.) Moench. and Alnus glutinosa (L.) Gaertn.

2008 ◽  
Vol 53 (No. 2) ◽  
pp. 66-73 ◽  
Author(s):  
E.V. Banaev ◽  
V. Bažant
Keyword(s):  
Czech Republic ◽  
Natural Populations ◽  
West Siberia ◽  
Alnus Glutinosa ◽  
Natural Hybridization ◽  
Alnus Incana ◽  
The Czech Republic ◽  
Leaf Characteristics ◽  
Leaf Veins ◽  
Qualitative Characteristics

Variation of metric and qualitative characteristics of <i>A. incana</i> (L.) Moench. and <i>A. glutinosa</i> (L.) Gaertn. has been studied in 10 natural populations in West Siberia, Russia and the Czech Republic in connection with the problem of natural hybridization. Morphological peculiarities of the species and their spontaneous hybrids are shown. Twelve leaf characteristics were used, in addition, qualitative characteristics were assessed, such as: type of bark, degree of pubescence of leaves and stems, and presence of a &ldquo;tuft&rdquo; in the angles of leaf veins. The reasons for hybridization of these species are discussed.

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
Keyword(s):  
Mechanical Properties ◽  
Czech Republic ◽  
The Czech Republic

Physical and mechanical properties and energy-saving modes of drying wood of black alder without artificial humidification in convective drying chambers of periodic action

10.12737/2193 ◽  
2014 ◽  
Vol 3 (4) ◽  
pp. 138-142
Author(s):  
Чернышев ◽  
Aleksandr Chernyshev
Keyword(s):  
Mechanical Properties ◽  
Energy Saving ◽  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Convective Drying ◽  
Operating Parameters ◽  
Interior Decoration ◽  
Periodic Action ◽  
Black Alder

Alder gains increasing popularity just like alternative to expensive raw materials. Detai-led technique of the studies is proposed. The basic physical and mechanical properties of black alder wood are given, its properties as a material for furniture and interior decoration are examined. Beforehand dehydrating pro-cess of alder was mathematically modeled, values of transient humidity and other key operating parameters were obtained, and then practical industrial drying on parabolic modes was implemented. These modes include four stages with the initial warming and final WTP.

Study of the Mechanical Properties Development of Concrete Containing Fine Recycled Aggregate

2016 ◽  
Vol 827 ◽  
pp. 267-270 ◽  
Author(s):  
Magdaléna Šefflová ◽  
Tereza Pavlů
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Czech Republic ◽  
Recycled Aggregate ◽  
Future Research ◽  
Building Structures ◽  
Replacement Ratio ◽  
The Czech Republic ◽  
Concrete Mixtures ◽  
Concrete Properties

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.

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