scholarly journals Changes in the volume and proportion of large-sized pine wood quality classes in relation to the type of log manipulation

2010 ◽  
Vol 71 (3) ◽  
pp. 311-314
Author(s):  
Joanna Witkowska
Keyword(s):  
Wood Quality ◽  
Pine Wood

Zmiany miąższości i udziału klas jakości drewna wielkowymiarowego sosnowego w zależności od rodzaju manipulacji dłużyc

Are Rays and Resin Canals Causal Sites for Intra-Ring Checking in the Wood of Pinus Radiata?

IAWA Journal ◽  
2009 ◽  
Vol 30 (2) ◽  
pp. 189-198 ◽  
Author(s):  
Hema Nair ◽  
Brian Butterfield ◽  
Sandra Jackson
Keyword(s):  
Comparative Study ◽  
Pinus Radiata ◽  
Wood Quality ◽  
Radiata Pine ◽  
Structural Features ◽  
Linear Arrangement ◽  
Pine Wood ◽  
Kiln Drying ◽  
Tissue Area ◽  
Resin Canals

Pinus radiata D. Don (radiata pine) wood can develop a wood quality defect called ‘intra-ring checking’ (checks) during kiln drying. A study was conducted to examine if rays and resin canals were the initiation sites of checks, and if the presence of the rays and resin canals increased the susceptibility of radiata pine wood to checking. The structural features associated with checking were observed in images of thirteen oven-dried radiata pine disks. Six of the sixty checks observed were associated with rays and resin canals. It is clear from the observations that rays and resin canals could not be the primary sites for check development. A comparative study showed some differences between the checked and non-checked wood with respect to rays and resin canals. Checked wood showed a higher amount of tissue area occupied by rays than the nonchecked wood. Hence, it is possible that rays can influence the tendency of wood to check. Such a relationship was not seen with respect to resin canals. However, a difference in the arrangement of resin canals was observed between checked and non-checked wood. Checked wood showed a scattered arrangement of resin canals, while the non-checked wood showed a linear arrangement.

scholarly journals Timber Properties and Cellulose Crystallites Size in Pine Wood Cut in Different Sawing Patterns after Pretreatment with CH3COOH and H2O2 and Densification

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1607
Author(s):  
Andi Detti Yunianti ◽  
S Suhasman ◽  
A Agussalim ◽  
Musrizal Muin ◽  
Heru Arisandi
Keyword(s):  
Wood Surface ◽  
Wood Quality ◽  
Anatomical Structure ◽  
Spring Back ◽  
Pine Wood ◽  
Tangential Surface ◽  
Surface Compression ◽  
Structure Density ◽  
Tangential Directions ◽  
Ray Cell

One process to improve wood quality is densification or wood surface compression. Our study analyzed the changes in some basic properties of pine wood, including its anatomical structure, density, modulus of elasticity (MOE), and dimensions of cellulose crystallites, after densification following soaking pretreatment in CH3COOH and H2O2 at a concentration of 20%. Samples were sawn in radial and tangential directions for analysis of the wood. The results showed a change in the shape of tracheid cells from hexagonal to oval, as well as damage to the ray cell constituents on the tangential surface. The thickness decrease of the samples was in accordance with the target, which meant that spring-back was short. In general, the tangential boards had a higher density than the radial boards, with a lower MOE and crystallite dimensions. Our findings showed that the densified tangential board was stronger than the radial board.

scholarly journals Integral assessment of pine wood quality in provenance plantations of Archangelsk region

2008 ◽  
pp. 43-48
Author(s):  
S A Korchagov ◽  
S E Gribov ◽  
Yu M Andreev ◽  
N A Kljukvina
Keyword(s):  
Wood Quality ◽  
Pine Wood ◽  
Integral Assessment

Changing the face of short fiber –a review of the eucalyptus revolution

TAPPI Journal ◽  
2015 ◽  
Vol 14 (6) ◽  
pp. 353-359 ◽  
Author(s):  
PETER W. HART ◽  
RICARDO B. SANTOS
Keyword(s):  
Fossil Fuels ◽  
Wood Quality ◽  
Short Fiber ◽  
Fiber Volume ◽  
Private Industry ◽  
High Productivity ◽  
Paper Manufacturing ◽  
Short Rotation ◽  
Eucalypt Plantations ◽  
Eucalyptus Plantations

Eucalyptus plantations have been used as a source of short fiber for papermaking for more than 40 years. The development in genetic improvement and clonal programs has produced improved density plantations that have resulted in fast growing, increased fiber volume eucalypts becoming the most widely used source of short fibers in the world. High productivity and short rotation times, along with the uniformity and improved wood quality of clonal plantations have attracted private industry investment in eucalypt plantations. Currently, only a handful of species or hybrids are used in plantation efforts. Many more species are being evaluated to either enhance fiber properties or expand the range of eucalypt plantations. Eucalyptus plantations are frequently planted on nonforested land and may be used, in part, as a means of conserving native forests while allowing the production of high quality fiber for economic uses. Finally, eucalypt plantations can provide significant carbon sinks, which may be used to help offset the carbon released from burning fossil fuels. The development and expansion of eucalypt plantations represents a substantial revolution in pulp and paper manufacturing.

A method for rearing Arhopalus ferus (Mulsant) (Coleoptera Cerambycidae) larvae on a modified artificial diet

2015 ◽  
Vol 68 ◽  
pp. 353-359 ◽  
Author(s):  
A.M. Barrington ◽  
D.P. Logan ◽  
P.G. Connolly
Keyword(s):  
Introduced Species ◽  
Artificial Diet ◽  
Larval Density ◽  
Pine Bark ◽  
Pine Wood ◽  
Rearing Method ◽  
Sawn Timber

Burnt pine longhorn (BPL) Arhopalus ferus (Mulsant) (Coleoptera Cerambycidae) is an introduced species sometimes found in association with export logs and sawn timber A rearing method was developed to produce larvae of a known age number and quality for control trials Growth of larvae from newly hatched to 5 weeks was measured on a standard cerambycid artificial diet and on modified diets Replacing pine wood with pine bark sawdust increased survival at 5 weeks from 23 to 76 and mean weight from 9 to 21 mg There were significant interactions between the influences of three factors (diet period of rearing initial larval density) on the weight of surviving larvae Individual rearing was preferred for convenience and a standardised method was used to rear 8740 larvae for disinfestation trials Establishment and survival to 6 weeks for these larvae was 97

Wachstum und Wertleistung der Douglasie in Abhängigkeit von der Standraumgestaltung

2012 ◽  
Vol 163 (3) ◽  
pp. 96-104 ◽  
Author(s):  
Joachim Klädtke ◽  
Ulrich Kohnle ◽  
Edgar Kublin ◽  
Andreas Ehring ◽  
Hans Pretzsch ◽  
...  
Keyword(s):  
Wood Quality ◽  
Volume Growth ◽  
Static Stability ◽  
Douglas Fir ◽  
Breast Height ◽  
Monetary Analysis ◽  
Starting Conditions ◽  
Tree Number ◽  
Clear Differentiation ◽  
Further Development

Growth and value production of Douglas-fir under varying stand densities The investigation is focused on the effects of initial tree number and thinning on growth and value performance of Douglas-fir stands. Data base is a coordinated Douglas-fir spacing experiment in South Germany, started 40 years ago and comprising variants of tree numbers with 500, 1,000, 2,000 and 4,000 Douglas-firs per hectare. The treatment was performed according to a standardized experiment program. The results show that at low initial tree numbers, the diameter on breast height (DBH) of (pre)dominant trees at the beginning of the observations (with 12 m top height) is bigger than at higher initial plant numbers. Accordingly, the quotient of height (H) to DBH (as an indicator for tree's static stability) is lower. The further development of DBH and H/DBH quotient is decisively determined by stand treatment, which superimposes the effect of the initial tree number. The total volume growth shows a clear differentiation, too, the variants with initially high tree numbers appearing on top. In the monetary analysis, this ranking is reversed: despite a supposed inferior wood quality, the variants with lower initial tree numbers clearly outperform the ones with higher numbers in terms of value. From these results, the following silvicultural recommendations for Douglas-fir can be derived: the initial tree numbers should be in the range from 1,000 to 2,000 plants per hectare. On technically not accessible sites, even lower tree numbers may come into question. The strong influence of stand treatment on DBH and H/DBH development highlights the problem of postponed thinnings, for this causes growth and stability losses even under favorable starting conditions in terms of competition.

Influence of microwave processing on frame of films glues on an aqueous basis

2016 ◽  
Author(s):  
С.П. Исаев ◽  
К.А. Шевчук
Keyword(s):  
Electromagnetic Field ◽  
Microwave Radiation ◽  
Polyvinyl Acetate ◽  
Wood Quality ◽  
Microwave Processing ◽  
Phase Changes ◽  
Microwave Range ◽  
Adhesive Film ◽  
Modern Development ◽  
Experimental Researches

Современное развитие деревоперерабатывающей отрасли сопровождается существенным ростом объемов готовой продукции, производимой на основе клееной древесины. Качество выпускаемой клееной продукции во многом определяется свойствами применяемых клеев. Экспериментально исследовано влияние электромагнитного поля СВЧ-диапазона на структуру клеев, применяемых для склеивания древесины. Установлено, что СВЧ-обработка оказывает существенное влияние на микроструктуру поливинилацетатного клея Dorus 072. Структура клеевой пленки, обработанной СВЧ-излучением, имеет более высокую дисперсность, по сравнению с исходным полимером, которая выражается в среднем уменьшении глобул в 1,4 раза. Исследование фазового контраста пленки поливинилацетатного клея, обработанного СВЧ-излучением, позволило установить, что после обработки уменьшается фазовая неоднородность клеевой пленки и имеет место углубление дисперсности глобул полимера, приводящее к увеличению степени его упаковки с образованием однородной по структуре пленки. Экспериментальные исследования пленок карбамидоформальдегидного клея Dorus FU 406, подвергнутого СВЧ-обработке, показали, что структуры образцов пленок как обработанного, так и необработанного, клея не отличаются значительными изменениями. Исследование фазового сдвига по поверхности образца пленки карбамидоформальдегидного клея отражает распределение свойств материала и показывает, что СВЧ-обработка клея способствует образованию квазигомогенной структуры, формирование которой подтверждается уменьшением различий в границах фазовых переходов микроструктур отвержденного полимера. На основании проведенных экспериментов по исследованию структуры пленок клеев, применяемых для склеивания древесины, установлено, что в результате воздействия электромагнитного поля СВЧ-диапазона на клеевые растворы осуществляется нетепловая модификация, сопровождающаяся уменьшением размеров макромолекул полимера и формированием плотно упакованной структуры пленки. Полученные результаты позволяют сделать вывод о целесообразности дальнейших исследований по модификации клеев СВЧ-обработкой. Modern development of woodworking branches is accompanied by essential growth of volumes of the finished goods manufactured on the basis of glued wood. Quality of let out glued production in many respects is defined by properties of applied glues. Influence of an electromagnetic field of a microwave range on frame of the glues applied to coagglutination of wood is experimentally investigated. It is positioned that microwave processing makes essential impact on a microstructure of polyvinyl acetate glue Dorus 072. The frame of the adhesive film treated by microwave radiation, has higher dispersity in comparison with initial polymer which is expressed on the average reduction of globules in 1,4 times. Research of phase contrast of a film of the treated polyvinyl acetate glue by microwave radiation has allowed to position that after processing phase heterogeneity of an adhesive film decreases and the excavation of dispersity of globules of the polymer, leading to augmentation of degree of its packaging, forming an unimodal film on frame takes place. Experimental researches of films of amino-formaldehyde glue Dorus FU 406, subjected to microwave processing, have shown that Frames of samples of films both treated, and untreated glue do not differ significant changes. Research of phase alteration on a surface of the sample of a film of amino-formaldehyde glue reflects allocation of properties of a stuff and shows that glue microwave processing promotes formation of the quasi-homogeneous frame which formation proves to be true reduction of distinctions in borders of phase changes of microstructures hardning polymer. On the basis of the made experiments on research of frame of films of the glues applied to coagglutination of wood it is positioned that as a result of influence of an electromagnetic field of the microwave oven of a range on glutinous solutions not thermal modification accompanied by reduction of the dimensions of macromolecules of polymer and formation of densely packed frame of a film is carried out. The received results allow to draw a conclusion on expediency of the further researches on modification of glues by microwave processing.

scholarly journals Symmetric Nature of Stress Distribution in the Elastic-Plastic Range of Pinus L. Pine Wood Samples Determined Experimentally and Using the Finite Element Method (FEM)

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 39
Author(s):  
Łukasz Warguła ◽  
Dominik Wojtkowiak ◽  
Mateusz Kukla ◽  
Krzysztof Talaśka
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Stress Distribution ◽  
Moisture Content ◽  
Tool Geometry ◽  
Wood Fibers ◽  
Data Set ◽  
Plastic Deformations ◽  
Pine Wood ◽  
Elastic Plastic

This article presents the results of experimental research on the mechanical properties of pine wood (Pinus L. Sp. Pl. 1000. 1753). In the course of the research process, stress-strain curves were determined for cases of tensile, compression and shear of standardized shapes samples. The collected data set was used to determine several material constants such as: modulus of elasticity, shear modulus or yield point. The aim of the research was to determine the material properties necessary to develop the model used in the finite element analysis (FEM), which demonstrates the symmetrical nature of the stress distribution in the sample. This model will be used to analyze the process of grinding wood base materials in terms of the peak cutting force estimation and the tool geometry influence determination. The main purpose of the developed model will be to determine the maximum stress value necessary to estimate the destructive force for the tested wood sample. The tests were carried out for timber of around 8.74% and 19.9% moisture content (MC). Significant differences were found between the mechanical properties of wood depending on moisture content and the direction of the applied force depending on the arrangement of wood fibers. Unlike other studies in the literature, this one relates to all three stress states (tensile, compression and shear) in all significant directions (anatomical). To verify the usability of the determined mechanical parameters of wood, all three strength tests (tensile, compression and shear) were mapped in the FEM analysis. The accuracy of the model in determining the maximum destructive force of the material is equal to the average 8% (for tensile testing 14%, compression 2.5%, shear 6.5%), while the average coverage of the FEM characteristic with the results of the strength test in the field of elastic-plastic deformations with the adopted ±15% error overlap on average by about 77%. The analyses were performed in the ABAQUS/Standard 2020 program in the field of elastic-plastic deformations. Research with the use of numerical models after extension with a damage model will enable the design of energy-saving and durable grinding machines.

Sign in / Sign up

Export Citation Format

Share Document