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Wyświetlanie 1-5 z 5
Tytuł:
Rozmiar uszkodzeń i strat olszowego drewna łuszczarskiego pozyskanego harwesterem Valmet 911.4 z głowicą 360.2
Wood damage and value loss of alder plywood harvested by Valmet 911.4 harvester with a 360.2 head
Autorzy:
Karaszewski, Z.
Łacka, A.
Bembenek, M.
Mederski, P.S.
Powiązania:
https://bibliotekanauki.pl/articles/989450.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
wood damage
harvesters
feed rollers
loss of wood
alnus glutinosa
wood quality
Opis:
The delimbing and bucking of timber using a harvester head is very productive in comparison with a chainsaw operations, however it can cause damage to the outer layer of round wood. This damage can originate from the delimbing knives or from the feed roller spikes. As a consequence, grey fungi can develop on coniferous species, and faster wood drying is also observed (with no regard to the species). Feed roller spikes create cuts and dents on the outer layers of the wood. When plywood is processed, the cuts and dents are recognised as damage as a consequence, they lower the wood quality and value. The objective of the presented research was to find out: 1) the depth of cuts, 2) the potential loss of volume, and 3) product value loss due to damage to plywood caused by feed roller spikes. The research was carried out on alder (Alnus glutinosa Geartn.) plywood logs harvested by a Valmet 911.4 with a 360.2 head. Measurements were taken using an electronic calliper with an accuracy of 0.01 mm. 16 plywood logs were considered, on which 384 measurement points (depth of spike cuts) were selected on different areas along the length of the log: 1, 2, 3 and 4 m from the butt end. The maximum depth of the spike cut was observed on the bottom part of the logs (1 m from the butt end) and amounted to 3.9 mm. This damage depth was statistically different to those at the 2nd, 3rd and 4th metre points, amounting to 1.9, 1.9 and 2.1 mm, respectively. The biggest volume losses were on the 1st metre of the plywood assortments: 0.004 m³ (4% of the volume), while on the further parts (2nd, 3rd and 4th metres) only 0.002 m³ of the plywood had damage (2% of the volume). In addition, the highest product value loss was on the butt end logs and amounted to 302 PLN/€72 per 100 m³. The following plywood assortments (2 nd , 3th and 4 th metres) had a loss of 76 PLN/€18 per 100 m³. Therefore, when plywood assortments are processed using a Valmet 911.4 harvester with a 360.2 head, it is recommended that after cutting and felling a tree, the plywood section of the alder tree trunk is cut off without feeding it through the harvester head.
Źródło:
Sylwan; 2016, 160, 12; 1002-1009
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of the Presence of Foreign Bodies on Quality and Value of Oak Timber
Autorzy:
Michalec, Krzysztof
Wąsik, Radosław
Gach, Monika
Powiązania:
https://bibliotekanauki.pl/articles/27323539.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Drewna
Tematy:
wood classification
mechanical damage to wood
wood defects
metal fragments
projectiles
Opis:
The paper discusses the impact of the presence of foreign bodies on the quality and value of oak timber as raw material. During the study, 109 oak bolts and logs with a total volume of 142.52 m 3 were measured and classified. The material for the study came from the Suchowice Forest District, within the Henryków Forestry Inspectorate (in the south-western part of Poland), and it was sampled from a tree stand located on the edge of the forest, where the largest concentration of rifle and artillery fire had occurred during World War II. As a result, the tree trunks contain significant amounts of shrapnel and projectiles. The length and diameter of each bolt and log were measured, and double classification was conducted: the first (I) classification took into account the presence of foreign bodies, whereas in the second (II) classification the presence of foreign bodies was disregarded. As a result of the conducted analyses, it was found that due to the presence of foreign bodies, all of the examined oak raw material was categorised as the worst quality class (D) timber. However, it was noted that during the second classification, where the presence of foreign bodies was not taken into account, a significant part of the raw material was upgraded to better quality classes, and only about 16% of wood remained in the worst, D class. Subsequently, it was calculated that the difference in the total value of the oak timber raw material classified by two methods amounted to approx. 204 thousand PLN (ca. € 43,514) – which was about 35% higher than the value calculated by the first method of classification.
Źródło:
Drewno. Prace Naukowe. Doniesienia. Komunikaty; 2023, 66, 211; Art. no. 1644-3985.438.05
1644-3985
Pojawia się w:
Drewno. Prace Naukowe. Doniesienia. Komunikaty
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stawonogi uszkadzające drewno w badaniach poligonowych
Arthropods that destroy wood during the field-tests
Autorzy:
Krajewski, A.
Monder, S.
Powiązania:
https://bibliotekanauki.pl/articles/1013191.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
mrowkowate
rownonogi
stawonogi
Harpagoxenus sublaevis
mrowka zlodziejka
drewno
prosionek szorstki
ochrona drewna
szkodniki drewna
hurtnica wstydliwa
Porcellio scaber
Lasius brunneus
Solenopsis fugax
badania poligonowe
arthropods
wood damage
field test
Opis:
Paper presents an overview of arthropods observed during the field test. Influence of these insects on protected and control samples was analysed and observed damages were described.
Źródło:
Sylwan; 2008, 152, 08; 47-53
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Madonna del Velo z przedstawieniem kardynała Paola Emilia Sfondratiego ze zbiorów wilanowskich w świetle ostatnich prac badawczych i konserwatorskich
Madonna del Velo with the portrait of Cardinal Paolo Emilio Sfondrati, extant in the Wilanów collection, in the light of recent research and conservation works
Autorzy:
Gutowska-Dudek, Krystyna
Modzelewska, Elżbieta
Strombek, Joanna
Kozakiewicz, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/1968048.pdf
Data publikacji:
2019
Wydawca:
Muzeum Pałacu Króla Jana III w Wilanowie
Tematy:
Madonna del Velo
painting
Cardinal Paolo Emilio Sfondrati
Wilanów
Potocki family
historical research
conservation research
technical research
painting materials
panel painting surface
pigments
binding agents
painting technology
identification of wood
board construction
poplar wood
chestnut wood
consolidation
wax
water damage
unstable paint layer
Opis:
A valuable work associated with the output of Raphael is extant in the collection of the Museum of King Jan III's Palace at Wilanów. It constitutes a repetition of The Holy Family, a work by the Urbino master which used to be located in the church of Santa Maria del Popolo in Rome and which has been considered lost. The painting, also known as the Madonna del Velo, is now believed to be one and the same as The Holy Family or, as an alternative name, La Madone de Lorette, currently in Musée Condé in Chantilly. The history of Raphael's original is complex and often mysterious. Over a hundred of its copies and variants are known. Enchanted with the beauty of this work, Cardinal Paolo Emilio Sfondrati (1560-1618), a presbyter of the church of Santa Cecilia in Trastevere, purchased it in 1591 and allegedly commissioned two copies of it for his brothers. The author added the figure of an angel and a portrait of the cardinal to Raphael's original composition. The links known to have existed between Cardinal Sfondrati and the outstanding Baroque painter Guido Reni (1575-1642), as well as extant drawings and prints, have promoted the conjecture that he might be the author of this exceptional work. However, an exhaustive study of Guido Reni's output and a careful investigation of archive materials in Poland and in Italy are required to determine its authorship. The painting arrived in Wilanów around the middle of the 19th century, when the palace was owned by Count and Countess August Potocki. Four articles pertain to one of the most interesting, and most valuable, paintings in the Wilanów collection, the Madonna del Velo, discussing various issues linked with its history, its study and its conservation. The Wilanów version is particularly interesting because of its high artistic quality and the fact that it shares some stylistic features with works by Raphael considered to be its prototypes. The technological structure of the Wilanów painting and the materials used in its making were investigated in the course of a research project and with the involvement of many scholars representing various areas of expertise. Analyses were conducted which made it possible to describe the board used as the painting surface, the pigments and the binding agents of the painting's layers, which is of considerable importance in further research on the workshop that produced the work. An account of the recent conservation interventions involving this painting is appended to the material.
Źródło:
Studia Wilanowskie; 2019, XXVI; 119-152
0137-7329
2720-0116
Pojawia się w:
Studia Wilanowskie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and numerical investigations of laminated veneer lumber panels
Badania eksperymentalne i numeryczne paneli z drewna klejonego warstwowo z fornirów
Autorzy:
Chybiński, Marcin
Polus, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/1852333.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
drewno warstwowo klejone
fornir
LVL
metoda elementów skończonych
wyrób drewniany
konstrukcja drewniana
konstrukcja zespolona
kryterium Hashin’a
laminated veneer lumber
finite element analysis
wood product
timber structure
composite structure
Hashin damage model
Opis:
This paper presents a study of laminated veneer lumber panels subjected to bending. Laminated veneer lumber (LVL) is a sustainable building material manufactured by laminating 3-4-mm-thick wood veneers, using adhesives. The authors of this article studied the behaviour of type R laminated veneer lumber (LVL R), in which all veneers are glued together longitudinally - along the grain. Tensile, compressive and bending tests of LVL R were conducted. The short-term behaviour, load carrying-capacity, mode of failure and load-deflection of the LVL R panels were investigated. The authors observed failure modes at the collapse load, associated with the delamination and cracking of veneer layers in the tensile zone. What is more, two non-linear finite element models of the tested LVL R panel were developed and verified against the experimental results. In the 3D finite element model, LVL R was described as an elastic-perfectly plastic material. In the 2D finite element model, on the other hand, it was described as an orthotropic material and its failure was captured using the Hashin damage model. The comparison of the numerical and experimental analyses demonstrated that the adopted numerical models yielded the results similar to the experimental results.
W pracy przedstawiono wyniki badań zginanych paneli wykonanych z drewna klejonego warstwowo z fornirów (LVL). Materiał zgodny z ideą zrównoważonego budownictwa powstaje przez połączenie 3–4 mm fornirów za pomocą kleju. Autorzy badali zachowanie drewna klejonego warstwowo z fornirów, w którym wszystkie forniry są sklejone wzdłużnie – wzdłuż włókien (LVL R). Wyznaczono wytrzymałość materiału LVL R na rozciąganie, ściskanie i zginanie. Określono zachowanie, nośność, formę zniszczenia paneli LVL R oraz zależność siła-przemieszczenie. Autorzy zaobserwowali formę zniszczenia paneli związaną z rozwarstwianiem warstw materiału oraz z pękaniem fornirów w rozciąganej strefie panelu. Przygotowano dwa modele numeryczne panelu LVL R i porównano ich zachowanie z laboratoryjną próbą zginania. W trójwymiarowym modelu numerycznym, zachowanie LVL R opisano za pomocą modelu sprężysto-idealnie plastycznego. W dwuwymiarowym modelu numerycznym materiał LVL R opisano, wykorzystując model ortotropowy a jego zniszczenie uwzględniono, biorąc po uwagę kryterium Hashin’a. Wyniki otrzymane z analiz numerycznych były zbliżone do rezultatów badań.
Źródło:
Archives of Civil Engineering; 2021, 67, 3; 351-372
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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