Miklós Bak - Academia.edu (original) (raw)

Papers by Miklós Bak

Environmental science and engineering, Dec 31, 2022

Gels, Apr 10, 2024

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

IOP conference series, 2023

Gradus, 2021

Összefoglalás A cikkben ismertetjük a rostirányban tömörített, továbbá hőkezeléssel, valamint tej... more Összefoglalás A cikkben ismertetjük a rostirányban tömörített, továbbá hőkezeléssel, valamint tejsavas telítéssel modifikált faanyagok fehér-és barnakorhadást okozó gombafajokkal szembeni ellenálló képességét. Azon tejsavas bükk (Fagus sylvatica) minták ellenállóbbnak bizonyultak, melyeket telítést megelőzően tömörítettünk is. A modifikáción átesett kocsánytalán tölgy (Quercus petraea) minták mindegyike nagyobb gombaállóságot mutatott lepketaplóval (Trametes versicolor) szemben, mint a kezeletlenek.

Innovative production technologies and increased wood products recycling and reuse Brno, Czech Re... more Innovative production technologies and increased wood products recycling and reuse Brno, Czech Republic, 29

Bioresources, Sep 6, 2012

In this work, the effect of oil heat treatment (OHT) on the swelling properties and changes in th... more In this work, the effect of oil heat treatment (OHT) on the swelling properties and changes in the rate of moisture uptake of poplar wood (Populus × euramericana cv. Pannónia) were investigated. Eighteen different treatments (combinations of three vegetable oils, two temperatures, and three durations) were studied. The results showed that OHT decreases the equilibrium moisture content (EMC) and the swelling of poplar wood. The degree of swelling and the EMC are influenced by both the duration and temperature of treatment. With an increase in duration and temperature, the EMC decreased. Consequently, the anti-swelling efficiency (ASE) increased. OHT wood adsorbs less moisture than natural wood, but it reaches a maximum-EMC at the momentary climateat the same time under all the investigated treatments. The moisture uptake is fastest in the beginning and thereafter it slows significantly. Decreasing the moisture uptake by OHT wood is due to the decreasing of its water storage capacity.

Fibers and Polymers, Dec 1, 2022

Bioresources, Jan 23, 2015

The aims of this study were to use beeswax impregnation as a wood preservative method and to eval... more The aims of this study were to use beeswax impregnation as a wood preservative method and to evaluate its suitability to protect wood species with low resistance to decay. Poplar (Populus × euramericana cv. Pannonia) and beech (Fagus sylvatica) samples were impregnated with beeswax and exposed to soil contact for 18 months. Impregnated samples were separated into three groups, on the basis of their degrees of pore saturation (DPS). With progressing decay, the load-bearing capacity and modulus of elasticity (MOE) of the woods decreased. After one month of soil contact, there was a marked decrease in MOE, which is explained by the increase in the moisture content of the wood. After 18 months, control samples were completely decayed. Nevertheless, impregnated samples showed less decay and a noticeable remaining load-bearing capacity. Impregnation efficiency had a pronounced effect on decay resistance. In both investigated species, samples with higher DPS resulted in less of a decrease in MOE than in samples with lower DPS. Although beeswax is a bio-based material, it showed noticeable decay resistance effects against soft rot. Scanning electron microscopy investigations showed that the impregnation has a barrier effect, mostly in the longitudinal direction, against the spread of the fungi.

Drewno, 2014

Due to its extraordinary hardness, decorative appearance and possible small dimensions, black loc... more Due to its extraordinary hardness, decorative appearance and possible small dimensions, black locust wood is assumed to be an excellent material for strip parquet flooring. The favourable colour changes achieved by controlled steam treatment further increased the utilization potential of this material. Flooring was installed on a student dormitory stair landing in heavy use. Due to the flooring's very high exposure, 5 years was considered a long enough period to compare the different face layer materials during in-service test. Oil was used as a coating to avoid the remarkable protecting effect of hard film-forming varnishes (acrylic, etc.) against abrasion. Besides the flooring turning grey (all face layers no matter what treatment), only some delamination occurred at certain places after five years in service. The laboratory test results for abrasion resistance, dimensional changes and deformation were analysed. Additionally, the Brinell-Mörath hardness after indoor service and the abrasion due to indoor service were analysed. In terms of abrasion resistance, dimensional changes and deformation, no essential differences were found between the oil-treated and untreated black locust wood on the one hand, and the control oak specimen on the other. Long-term tests showed that, after 5 years in service, the Brinell-Mörath-hardness decreased considerably for all the tested materials. The type of section and the presence of wide rays influenced the roughness and the waviness of the surface after indoor service.

Journal of Photochemistry and Photobiology A-chemistry, Oct 1, 2016

Black locust (Robinia pseudoacacia L) samples with high extractive content and poplar (Populus Â ... more Black locust (Robinia pseudoacacia L) samples with high extractive content and poplar (Populus Â euramericana cv. Pannónia) samples with low extractive content were chosen for the test. The specimens were thermally treated at 160 and 200 C in sunflower oil for 2, 4, and 6 h then irradiated by a strong UV emitter mercury lamp up to 36 h. The effects of thermal treatment and UV radiation were monitored by colour measurement. The results indicated that the extractives play an important role in the photodegradation of oil-heat treated wood. Thermal treatments reduced the lightness change effect of photodegradation. The oil-heat treated black locust samples showed similar photodegradation properties independently on the thermal pre-treatment time and temperature. The redness of oilheat treated black locust samples hardly changed during UV radiation proving the photostability of the thermally modified extractives. The redness change of poplar samples caused by UV radiation was partly determined by the temperature of thermal treatment (darkening and lightening also happened). The yellow colour change of the investigated samples showed that the lignin of thermally modified wood undergoes similar photodegradation as that of the untreated natural wood. 2016 Elsevier B.V. All rights reserved.

Coatings, Jun 10, 2022

Journal of The Textile Institute, Nov 12, 2021

Journal of Cultural Heritage, Sep 1, 2021

The present paper studied wood-water relations and their effects on color changes. Additionally, ... more The present paper studied wood-water relations and their effects on color changes. Additionally, FTIR analysis of recent and archaeological oak wood was completed. Comprehensive knowledge of woodwater relations in recent and archaeological oak wood will facilitate the use of treatment material in the restoration and conservation process of the investigated artefacts. Wood samples were impregnated with tetraethyl orthosilicate. Sorption time until equilibrium moisture was reached increased significantly as a result of the treatment. Thus, the saturation time for treated recent oak wood was 43% longer than it was for untreated recent oak. Additionally, the treatment increased sorption time to equilibrium moisture in archaeological oak by 63%. The treatment resulted in significant color changes for both recent and archaeological oak wood. Samples displayed less color difference when they were dry compared to when they were wet. According to the FTIR analysis, tetraethyl orthosilicate causes the increase of the amount of O-H groups in archaeological oak wood and also caused an increase in the of the amount of C = O groups. This change is due to the hiding effect of xerogel formation on the functional group of wood.

Composite Interfaces, Sep 28, 2021

Bioresources, Aug 30, 2018

The efficacy of five different nanoparticles (zinc-oxide, zinc-borate, silver, copper, and copper... more The efficacy of five different nanoparticles (zinc-oxide, zinc-borate, silver, copper, and copper-borate) were evaluated after application at different concentrations for protection against Coniophora puteana and Coriolus versicolor. Tests were performed with two different wood species (beech and pine sapwood). Furthermore, tests were done to investigate the resistance of the nanoparticles to leaching. Overall, the results of the efficiency of the investigated nanoparticles against the brown and white rot fungi were diverse. One of the investigated fungi showed a tolerance to the nanoparticles in some cases (zinc-oxide, silver nanocubes, and copper). The most effective nanoparticle treatments were those containing borate. However, only the zinc-oxide, copper, and silver nanoparticles showed a high resistance to leaching. Unfortunately, zinc-borate and copper-borate showed a low resistance to leaching, as the treated samples showed a similar decay compared with that of the control. Thus, only the zinc-oxide at the highest investigated concentration (5% m/m) provided effective protection after leaching for both of the investigated fungi. Also, the copper nanoparticles showed potential as an effective treatment at higher concentrations.

A pannónia nyár (Populus × euramericana Pannónia) és az akác (Robinia pseudoacacia) faanyagok hők... more A pannónia nyár (Populus × euramericana Pannónia) és az akác (Robinia pseudoacacia) faanyagok hőkezelése 160 és 200ºC-os növényi olajban történt, így biztosítva az oxigén kizárását a folyamat során. A hőkezelés napraforgóolajjal, lenolajjal, és repceolajjal történt, mindegyiknél 2, 4 és 6 óra kezelési időkkel. A cél annak a megállapítása volt, hogy az eljárás miként befolyásolja a két fafaj kiválasztott tulajdonságait (hajlító-, ütő-törő-, és nyomószilárdság, dimenzióstabilitás, szín), és hogy ezen belül a különböző olajok és kezelési idők okozta változások közt mi a különbség. Kontrollként kezeletlen minták szolgáltak. Szilárdság szempontjából a két fafaj csak az ütő-törő szilárdság terén viselkedett hasonlóan, itt mindkét fafajnál csökkenés következett be. A hajlítószilárdsági értékek tekintetében az akácnál hasonló változás történt, míg nyárnál a változás ezzel ellentétes volt, a két legintenzívebb menetrendnél pedig nőtt a szilárdság. A nyomószilárdsági értékek tekintetében a nyárnál egyértelmű szilárdságnövekedés következett be. Akác esetében a hőmérséklettől függően változott a szilárdság. A dimenzióstabilitás egyértelműen javult mindkét fafajnál, a kezelési hőmérséklet és idő növekedésével arányosan nőtt. A színváltozás a két fafajnál hasonló tendenciát mutatott, azaz a kezelési hőmérséklet és idő növekedésével arányosan egyre sötétebb árnyalatú lett. A CIELab színkoordináták közül az L* és az a* azonos irányba tolódott el mindkét fafajnál, a b* színkoordináta azonban ellenkező irányba. A vizsgálatok során a háromféle olaj okozta változások között nem jelentkezett kimutatható eltérés. Összességében elmondható, hogy a nyár jobban viselte a kezelést, akácnál gyakori probléma volt a gyors nedvességvesztés miatti belső gőznyomás hatására kialakult repedés a próbatestek belsejében. ez a jelenség nem fordult elő.

Forests, Mar 22, 2023

A szilvafélék alcsaládjába tartozó fafajok közül elsősorban a madárcseresznye (Cerasus avium) fai... more A szilvafélék alcsaládjába tartozó fafajok közül elsősorban a madárcseresznye (Cerasus avium) faipari felhasználásának van jelentősége napjainkban, emellett azonban figyelmet érdemel a hasonlóan esztétikus megjelenésű és tulajdonságú faanyagot szolgáltató zselnicemeggy (Prunus padus) is. Bár kisebb termete miatt felhasználása korlátozott, értékes faanyagról lévén szó, nem szabad mellőzni a feldolgozását. Ennek során azonban figyelembe kell venni, hogy a zselnicemeggy fizikai tulajdonságai némileg eltérnek a madárcseresznyéétől.

The variability of ovendry density on 12 giant fir logs (Abies grandis) was investigated. Statist... more The variability of ovendry density on 12 giant fir logs (Abies grandis) was investigated. Statistical analysis was made also. The variation of the ovendry density was determined regarding to the different Kraft classes, heights and radial wood zones (sapwood, heartwood and compression wood). The difference between the ovendry density of the trees from the Kraft class 1 and 3 is not significant. According to the determined radial gradients the highest ovendry density was always measured in the outermost parts (next to the cambium) while the lowest ovendry density was measured in the innermost part of the heartwood (juvenile wood). In longitudinal direction the ovendry density showed at 1.5 m tree height the highest and at 7.5 and 14.0 m the lowest values. The density of the heartwood was lower than the density of the sapwood and compression wood at all investigated tree heights. The ovendry density of the compression wood reached values between the heartwoods and the sapwoods density, at all investigated tree heights. The test results provide a solid and practical basis for the timber grading of the giant fir logs.

Construction and Building Materials, Oct 1, 2021