Archiv článků od 19.6.2017 do 18.6.2018

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The Formation of Gaseous Products at Thermal Degradation of the Retardant Treated Fir Wood

18.6.2018 | Ing. Veronika Veľková, PhD., prof. RNDr. Danica Kačíková, PhD., prof. RNDr. František Kačík, PhD., Ing. Tatiana Bubeníková, PhD., Ing. Katarína Trebulová, Drevárska fakulta, Technická univerzita vo Zvolene
The work is focused on the investigation of the formation of gaseous thermal degradation products of retarded firwood. Samples of firwood were impregnated with solutions of 6 inorganic salts, thermally loaded and the arising gaseous products analyzed by SPME-GC-MS. There were 20 compounds identified, the highest amount was achieved for acetic acid and 2-furaldehyde as typical representatives of wood degradation. Most compounds were identified by degradation of samples treated with boric acid solution, at least with ammonium dihydrogenphosphate. The smallest amount of acetic acid and 2-furaldehyde was determined by treating of fir samples with sodium tetraborate solution, which appears to be a very suitable wood treatment agent for fire protection.

Environmental benefits of using recycled wood to produce agglomerated materials (Part 3)

21.5.2018 | doc. Ing. Milan Gaff, Ph.D., Ing. Kamil Trgala, Ph.D., Ing. Tereza Adamová, Česká zemědělská univerzita v Praze (ČZU), Fakulta lesnická a dřevařská, katedra dřevěných výrobků a konstrukcí
Wood and the materials on its basis fulfil the requirements of an ever-evolving and accelerating society. In addition to naturally grown wood, wood-based materials are frequently used as a basic material for production of furniture and for building constructions as well. Looking at changes in waste management, a significant shift from the waste to the circular economy can be observed. The valuable raw materials are kept in the production cycle instead of landfilling or burning. Wood and wooden products can be efficiently separated in waste management, reused and recycled. The so-called wood waste – old furniture, wooden pallets, window and door frames, demolition wood, used lumber, bark and other wood residues can be reused in particleboard production. Particle board manufacturers in the Czech Republic have adopted progressive waste management and currently use 60% of recycled wood into particle boards. A completed life cycle analysis (LCA) of OSB demonstrates that replacing of 50% of natural fibres with recycled wood has significant environmental benefits. The objective is to push furthermore on effective legislation to promote waste material utilization and thus lead to a more sophisticated waste wood collecting.

Environmental benefits of using recycled wood to produce agglomerated materials (Part 2)

14.5.2018 | doc. Ing. Milan Gaff, Ph.D., Ing. Kamil Trgala, Ph.D., Ing. Tereza Adamová, Česká zemědělská univerzita v Praze (ČZU), Fakulta lesnická a dřevařská, katedra dřevěných výrobků a konstrukcí
Wood and the materials on its basis fulfil the requirements of an ever-evolving and accelerating society. In addition to naturally grown wood, wood-based materials are frequently used as a basic material for production of furniture and for building constructions as well. Looking at changes in waste management, a significant shift from the waste to the circular economy can be observed. The valuable raw materials are kept in the production cycle instead of landfilling or burning. Wood and wooden products can be efficiently separated in waste management, reused and recycled. The so-called wood waste – old furniture, wooden pallets, window and door frames, demolition wood, used lumber, bark and other wood residues can be reused in particleboard production. Particle board manufacturers in the Czech Republic have adopted progressive waste management and currently use 60% of recycled wood into particle boards. A completed life cycle analysis (LCA) of OSB demonstrates that replacing of 50% of natural fibres with recycled wood has significant environmental benefits. The objective is to push furthermore on effective legislation to promote waste material utilization and thus lead to a more sophisticated waste wood collecting.

Environmental benefits of using recycled wood to produce agglomerated materials (Part 1)

7.5.2018 | doc. Ing. Milan Gaff, Ph.D., Ing. Kamil Trgala, Ph.D., Ing. Tereza Adamová, Česká zemědělská univerzita v Praze, Fakulta lesnická a dřevařská
Wood and the materials on its basis fulfil the requirements of an ever-evolving and accelerating society. In addition to naturally grown wood, wood-based materials are frequently used as a basic material for production of furniture and for building constructions as well. Looking at changes in waste management, a significant shift from the waste to the circular economy can be observed. The valuable raw materials are kept in the production cycle instead of landfilling or burning. Wood and wooden products can be efficiently separated in waste management, reused and recycled. The so-called wood waste – old furniture, wooden pallets, window and door frames, demolition wood, used lumber, bark and other wood residues can be reused in particleboard production. Particle board manufacturers in the Czech Republic have adopted progressive waste management and currently use 60% of recycled wood into particle boards. A completed life cycle analysis (LCA) of OSB demonstrates that replacing of 50% of natural fibres with recycled wood has significant environmental benefits. The objective is to push furthermore on effective legislation to promote waste material utilization and thus lead to a more sophisticated waste wood collecting.

Roof Windows for Passive Buildings

7.5.2018 | prof. Ing. Jan Tywoniak, CSc., ČVUT Praha, pracoviště UCEEB
The paper presents the building-physical context of the use of roof windows in buildings with very low energy demand. It shows their relatively significant influence on the total heat loss of a single family house and the consequence of the specific disadvantageous set-up in the pitched roof. It is shown that the thermal transmittance should not exceed 0.7 W/(m2K) with a strict limitation of thermal coupling in the connection to the roof. In the second part, the paper shows the positive effect of the slanting of the inner lining on the quality of day lighting.

Experimental analysis aimed at function verification of fiber optic sensors

23.4.2018 | Ing. Lukáš Velebil, Ing. Jan Včelák, Ph.D., Ing. Kristýna Čápová, ČVUT v Praze, pracoviště UCEEB, Ing. Milan Dvořák, Safibra Říčany
The paper deals with the experimental analysis aimed at function verification of fiber optic sensors (Fiber Bragg Gratings). The sensors are used for mechanical stress measurement in wooden load-bearing structures. Glued laminated timber beam with built-in fiber optic sensor system was mechanically loaded during two bending tests. The data obtained using the fiber optic sensors were compared with the results of reference measurement method and analytical calculation.

Fire protection of Norwegian and Polish wooden heritage buildings

19.3.2018 | Eva Polatová, Národní památkový ústav
This article focuses on the fire protection of wooden churches and other wooden structures that are listed in Norway and Poland and introduces several of them.

Determination of vertical forces from load of a wooden high-rise building

19.3.2018 | Ing. Luděk Vejvara, Ph.D., Západočeská univerzita v Plzni, Katedra mechaniky
The magnitude of the load on the walls of tall wooden constructions can be assembled according to the existing standards according to the valid combination equations in several ways. There are differences between the results. Determining the appropriate procedure for determining vertical strength from construction in different parts of building preparation and comparing it with other options is the subject of this paper.

Beech wood for building structures assessment

19.2.2018 | Ing. Ondrej Bajza, doc. Ing. Alena Rohanová, Katedra drevených stavieb, Drevárska fakulta, Technická univerzita vo Zvolene
The text describes why and under what conditions the use of beech wood in building structures. Given the legislative and experimental requirements for verification of properties of beech sorting into classes of forts "D". Evaluation of the quality beech wood over the strength of the reliable design, production technology class predictive level as well as the durability of wooden building elements.

Assessment of the influence of bulk density on flameless burning of cellulose insulation

12.2.2018 | Ing. Peter Rantuch, PhD., Ing. Jozef Martinka, PhD., prof. Ing. Karol Balog, PhD., Ing. Hana Kobetičová, Slovenská technická univerzita v Bratislave a Materiálovotechnologická fakulta so sídlom v Trnave, Ústav integrovanej bezpečnosti, Trnava
Cellulose insulation is one of the minority types of heat insulating materials, but their use has increased significantly in recent years. The aim of the contribution is to assess the impact of its bulk weight on the processes of smothering and glowing. The resistance wire was used as the initiator. In addition to visual observation, carbon dioxide concentrations and optical smoke density were also recorded. The results were evaluated in the form of graphs and tables.
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Physical and Mechanical Properties of Timber at Various Moisture

29.1.2018 | Ing. Věra Heřmánková, Ph.D., Ing. Ondřej Anton, Ph.D., Ing. Tereza Komárková, VUT Brno, Fakulta stavební, Ústav stavebního zkušebnictví
Article deals with finding of physical and mechanical properties of timber at various moisture and it also verifies addictions of single properties on moisture content of timber. In experimental part of this thesis, the density, the dimensional and volumetric swelling and the compressive strength parallel to fibre will be determined on test samples. After evaluating all the tests, the graphs of these parameters depend on various samples of wood moisture determined by weight will be created.
Fall colours in the Eastern Townships in Quebec, Canada © mbruxelle - Fotolia.com

Hardwood from North America and its use in Eastern Europe

4.12.2017 | Dr. Eva Haviarová, Purdue University, Department of Forestry and Natural Resources, Purdue, Ing. Milan Šimek, Ph.D., Mendelova univerzita v Brně, Lesnická a dřevařská fakulta, Dr. Henry Quesada, Virginia Tech University, Department of Sustainable Biomaterials
In the last two decades, the US hardwood industry has experienced an important increase in their exports to key markets in Southeast Asia, and Western Europe. However, the export to Easter Europe is currently limited. In these emerging economies, production of furniture and many different kinds of wood products are on the rise. Favorable labor costs, progressive design, and available material resources are key factors that sustain the growth of these industries. The forest products industry is also significant consumer of hardwood lumber. Despite the fact that Easter European countries have its own hardwood material resources, the rapid industry growth, increased sustainability practices, and increased demand of high quality material may require the need for additional material sourcing.
Šetrné diagnostické metody pro hodnocení bezpečnosti dřevěných konstrukcí

Safety assessment of historic timber structures using testing of very small specimens

16.10.2017 | Ing. Michal Kloiber, prof. Ing. Miloš Drdácký, DrSc., dr. h., Ústav teoretické a aplikované mechaniky AV ČR, Centrum excelence Telč
The paper discusses approaches to safety assessment of historic timber structures using testing of very small specimens extracted from a historic structure or by direct in-situ testing. The presented methods must to take into account conditions given by the EN 16085. They further consider environmental influences and correlations of characteristics achieved by various SDTs.
Rekonstrukce dřevěných trámových stropů

Reconstruction of wooden joist ceilings

9.10.2017 | Ing. Zdeněk Vejpustek, Ph.D., doc. Ing. Bohumil Straka, CSc.
The paper shows reasons for carrying out restoration of historic wooden ceiling using “dry method” – interaction between historic wooden beams and wood-based panels. This article summarizes the process of reconstruction of historic wooden ceilings, describes the problems to be addressed and it summarizes experience with completed ceilings in Brno,Czech Republic.
Nanomateriály a vybrané oblasti ich využitia

Nanomaterials and selected areas of their utilization

2.10.2017 | doc. Ing. Ivan Kubovský, PhD., Technická univerzita vo Zvolene, Drevárska fakulta, Katedra fyziky, elektrotechniky a aplikovanej mechaniky, Ing. Miroslav Gašparík, PhD., Česká zemědelská univerzita v Praze, Fakulta lesnická a dřevařská, Katedra základního zpracování dřeva, prof. RNDr. František Kačík, PhD., Technická univerzita vo Zvolene, Drevárska fakulta, Katedra chémie a chemických technológií
The possibilities of using nanomaterials are quite broad – from increasing the hydrophobicity and photostability of surfaces, through improving the mechanical properties of traditional materials, aiding in the diagnosis and therapy of certain diseases, repairing damaged parts of the tissue, and solving problems in decontamination of the environment. Intensive research also takes place in their applications to increase the resistance of wood to wood-boring fungi and wood-destroying insects. Nanomaterials, including nanocellulose, are perspective in the field of wood fire protection, which may be important in the evolving trend of wood building construction.

Structure of framework (part 4)

28.8.2017 | Ing. Jan Vinař, MURUS, monumenta renovamus, s.r.o.
The paper deals with the principles of structure, function, use, disfunction and repairs of frame houses (part 1 to 4).

Structure of framework (part 3)

21.8.2017 | Ing. Jan Vinař, MURUS, monumenta renovamus, s.r.o.
The paper deals with the principles of structure, function, use, disfunction and repairs of framework (part 1. to 4.)
Hamr na Jezeře - Konstrukční principy hrázděných staveb

Structure of framework (part 2)

14.8.2017 | Ing. Jan Vinař, MURUS, monumenta renovamus, s.r.o.
The paper deals with the principles of structure, function, use, disfunction and repairs of framework (part 1 to 4).
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Structure of framework (part 1)

7.8.2017 | Ing. Jan Vinař, MURUS, monumenta renovamus, s.r.o.
The paper deals with the principles of structure, function, use, disfunction and repairs of framework (part 1 to 5).
Administrativní budova Tamedia v Curychu

Technical Normalisation and Multi-Storey Timber Buildings

19.6.2017 | doc. Ing. Petr Kuklík, CSc., Ing. Lukáš Velebil, ČVUT v Praze, UCEEB, Ing. arch. Bc. Anna Gregorová, ČVUT v Praze
At present, there is growing interest in the realization of multi-storey wooden buildings. In the case of multi-storey wooden buildings, their safety, stiffness and acoustics are of key importance. The submitted paper focuses on the issue of fire safety of multi-storey wooden buildings, which is currently the subject of major discussions.
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