Wyniki wyszukiwania - BazTech

1

Study of wood surface pre-treatment by radio-frequency discharge plasma

Novák Igor, Sedliačik Ján, Krystofiak Tomasz, Lis Barbara, Popelka Anton, Kleinová Angela, Matyašovský Ján, Jurkovič Peter, Bekhta Pavlo

Drewno : prace naukowe, doniesienia, komunikaty

|

2019

|

vol. 62, nr 203

81--91

EN

An investigation was made of wood of the species oak (Quercus petraea), beech (Fagus sylvatica L.), maple (Acer pseudoplatanus) and ash (Fraxinus excelsior) pre-treated using radio-frequency (RF) plasma in air at reduced pressure. Physical and chemical changes for all of the wood species were determined using measurements of water contact angles and FTIR-ATR spectroscopy. The results confirmed an increase in the wood’s hydrophilicity/polarity in all cases, caused by an increase in –OH group concentration due to irradiation by RF plasma. The content of oxygen-containing functional groups after treatment by RF plasma significantly increased, and the water contact angles were diminished. FTIR-ATR spectroscopy confirmed that RF plasma modification of the surfaces of all investigated wood samples led to certain changes, which were also dependent on the time of plasma exposure.

2

Discharge plasma treatment of wood surfaces

Novák I., Kleinová A., Sedliačik J., Matyašovský J., Jurkovič P.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

|

2018

|

No. 104

169--173

EN

The water contact angle of various wood species treated by radio-frequency discharge (RFD) plasma in air decreased with activation time from 75 up to 40 deg. The growth of water contact angle of plasma-treated wood from 37 up to 68 deg during aging was faster within 2 days after the plasma pre-treatment. The water contact angles of tested wood species showed a steep decrease after activation by RFD plasma in air. Water contact angles were markedly increased during the first 2 days of aging. RFD plasma-treated wood surfaces should be treated up to 2 days after modification by plasma. The unmodified beech wood sample shows lower roughness compared to wood surface treated by RF-plasma. Higher roughness of the plasma-treated wood samples is related to the ablation of amorphous lignin on the surface of the beech wood.

3

Laccase treatment of Norway spruce wood surface improves resistance and copper fixation of treated wood

Vaukner Gabrič M., Boncina T., Humar M., Pohleven F.

Drewno : prace naukowe, doniesienia, komunikaty

|

2016

|

vol. 59, nr 198

19--33

EN

The effects of laccase from the white-rot basidiomycete fungus Trametes versicolor on Norway spruce wood (Pices abies) surface were studied. Experiments were performed at room temperature and at pH 4.6, without the addition of mediators. Biological, chemical and physical properties of the treated wood surface were examined by a wood decay test, a scanning electron microscopy (SEM), a Fourier transform infrared (FTIR) spectroscopy and a copper leaching test. Laccase pre-treatment of Norway spruce wood surface was shown to reduce wood decay by brown-rot fungus, Gloeophyllum trabeum and white-rot fungus, Trametes versicolor. SEM images showed expanded wood cell walls, closed pits and a more even surface after laccase treatment. FTIR analysis indicated that laccase not only catalyse depolymerisation of lignin, but also affect other wood cell wall components, such as hemicellulose and cellulose. We showed that laccase treatment altered wood properties in a way that improved wood resistance to decay and prevented leaching of copper from impregnated wood.

4

Znaki, inskrypcje i ślady na powierzchni drewna w zabytkowych konstrukcjach dachowych

Mączyński D.

Wiadomości Konserwatorskie

|

2009

|

Nr 25

28--36

PL

Interdyscyplinarne badania drewnianych, zabytkowych konstrukcji dachowych ujawniły wiele nowych informacji naukowych, dotąd pomijanych i w związku z tym w niedostateczny sposób udokumentowanych. Analiza znaków ciesielskich pozwala na uzyska- nie informacji na temat jednorodności i kompletności konstrukcji oraz dokonanych w niej zmian. Pokazuje także ewolucję techniki budowlanej. Pęknięcia przebiegające przez znaki ciesielskie mogą świadczyć o tym, że do budowy użyto świeżo pozyskanego drewna. Napisy, podpisy i daty zachowane na powierzchniach elementów pozwalają ustalić czas powstania konstrukcji, jej przebudowy lub naprawy oraz mogą pomóc zidentyfikować wykonawców. Zupełnie nowym odkryciem są zachowane na niektórych elementach konstrukcji napisy handlowe. Świadczą one o przygotowywaniu części konstrukcji poza placem budowy i dostarczaniu jej w formie obrobionych elementów, prawie gotowych do montażu. Bada się także ślady pozostawione w czasie obróbki drewna przez tradycyjne narzędzia ciesielskie. Pozwala to ustalić dawne techniki obróbki drewna, kształt użytych narzędzi i metody wznoszenia konstrukcji. Można także stwierdzić, czy prace wykonywała jedna ekipa cieśli, czy też kilka zespołów. W szerszej perspektywie uzyskane z takich badań informacje mogą posłużyć do analizy historii rozwoju ciesielstwa i budownictwa na większych obszarach naszego kontynentu. Część z odkrywanych śladów nadal wymaga odpowiedniej interpretacji. W Polsce, w czasie remontów dawnych więźb dachowych, bardzo często zaleca się ociosać powierzchnie uszkodzonych elementów drewnianej konstrukcji. Jeśli nie wykonano odpowiednich badań i dokumentacji, po takim zabiegu ważne informacje naukowe ulegają całkowitemu zniszczeniu.

EN

Interdisciplinary research on historic wooden roof constructions revealed plenty of new scientific information, previously ignored and thus insufficiently documented. Analysis of carpenters’ marks allows for obtaining information concerning the homogeneity and completeness of construction as well as alterations made to it. Moreover, it illustrates the evolution of building techniques. The cracks running through carpenters’ marks could serve as evidence that freshly felled timber was used for construction work. Marks, signatures and dates preserved on the surface of elements allow for ascertaining the time when the construction was erected, rebuilt or repaired, and could help to identify the builders. Tradesmen’s marks, preserved on some construction elements, are a completely new discovery. They serve as proof that some sections of constructions were prepared outside the building site and delivered in the form of shaped elements almost ready for assembling. Traces left by the traditional carpenter’s tools during wood processing are also examined. It allows for identifying old techniques of wood working, the shape of tools used and methods of erecting buildings. It can be also stated whether the work was performed by one or several teams of carpenters. In a wider perspective, information obtained from such research can be useful for the analysis of the history of development of carpentry and construction work in larger areas of our continent. Some of the discovered traces still require appropriate interpretation. In Poland, during repair work on old roof constructions, it is frequently recommended to hew the surface of damaged elements of the wooden structure. If no appropriate examination and documentation had been done earlier, then after such treatment important scientific information is utterly destroyed.