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Journal of Forestry Research 2014年第3期25卷 667-670页

作者： Seyedeh Masoumeh Hafezi Kazem Doosthoseini department of wood and paper sciences and technology Faculty of Natural Resources University of Tehran

We used silane coupling agents to improve the bonding ability between wheat straw particles and UF resin, and investigated surface properties （wettability and surface roughness） and hardness of parti-cleboard made from UF-bonded wheat straw （Triticum aestivum L.） combined with poplar wood as affected by silane coupling agent content and straw/poplar wood particle ratios. We manufactured one-layered particleboard panels at four different ratios of straw to poplar wood par-ticles （0%, 15%, 30% and 45% wheat straw） and silane coupling agent content at three levels of 0, 5% and 10%. Roughness measurements, average roughness （Ra）, mean peak-to-valley height （Rz）, and root mean square roughness （Rq） were measured on unsanded samples by using a fine stylus tracing technique. We obtained contact angle measurements by using a goniometer connected to a digital camera and computer sys-tem. Boards containing greater amounts of poplar particles had superior hardness compared to control samples and had lower wettability. Panels made with higher amounts of silane had lower Rq values.

关键词： wheat straw particleboard poplar wood surface properties,wettability silane coupling agent hardness

Cement-bonded particleboard with a mixture of wheat straw and poplar wood

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Journal of Forestry Research 2013年第2期24卷 381-390页

作者： Morteza Nazerian Vajiihe Sadeghiipanah department of wood and paper Science and technology University of Zabol

We investigated the hydration behavior and some physical/mechanical properties of cement-bonded particleboard （CBPB） containing particles of wheat straw and poplar wood at various usage ratios and bonded with Portland cement mixed with different levels of inorganic additives. We determined the setting time and compression strength of cement pastes containing different additives and particles, and studied the effects of these additives and particles on thickness swelling, internal bond strength and modulus of rupture of CBPB by using RSM （Response Surface Methodology）. The mathematical model equations （second-order response functions） were derived to optimize properties of CBPB by computer simulation programming. Predicted values were in agreement with experimental values （R2 values of 0.93, 0.96 and 0.96 for TS, IB and MOR, respectively）. RSM can be efficiently applied to model panel properties. The variables can affect the properties of panels. The cement composites with bending strength 〉 12.5 MPa and internal bond strength 〉 0.28 MPa can be made by using wheat straw as a reinforcing material. Straw particle usage up to 11.5% in the mixture satisfies the minimum requirements of International Standard, EN 312 （2003） for IB and MOR. The dose of 4.95% calcium chloride, by weight of cement, can improve mechanical properties of the panels at the minimum requirement of EN 312. By increasing straw content from 0 to 30%, TS was reduced by increasing straw particle usage up to 1.5% and with 5.54% calcium chloride in the mixture, TS satisfied the EN 312 standard.

关键词： cement-bonded particleboard wheat straw poplar additives setting time physical and mechanical properties

Improve regression-based models for prediction of internal-bond strength of particleboard using Buckingham's pi-theorem

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Journal of Forestry Research 2013年第4期24卷 735-740页

作者： Akbar Rostampour Haftkhani Mohammad Arabi department of wood & paper Science and technology Faculty of Natural ResourcesUniversity of Tehran

Internal bond （IB） strength is one of the most important me- chanical properties that indicate particleboard quality. The aim of this study was to find a simple regression model that considers the most important parameters that can influence on IB strength. In this study, IB strength was predicted by three kinds of equations （linear, quadratic, and exponential） that were based on the percentage of adhesive （8%, 9.5%, and 11%）, particle size （＋5, -5 ＋8, -8 12, and -12 mesh）, and density （0.65, 0.7, and 0.75 g/cm3）. Our analysis of the results （using SHAZAM 9 software） showed that the exponential function best fitted the experi- mental data and predicted the IB strength with 18~,/0 error. In order de- crease the error percentage, the Buckingham Pi theorem was used to build regression models for predicting IB strength based on particle size,

关键词： Buckingham's Pi theorem intemal bond strength particle-board screw withdrawal resistance.

Strength performance of mortise and loose-tenon furniture joints under uniaxial bending moment

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Journal of Forestry Research 2014年第2期25卷 483-486页

作者： Mohammad Derikvand Ghanbar Ebrahimi department of wood and paper Science and technology College of Natural ResourcesUniversity of Tehran

We determined the effects of adhesive type and loose tenon dimensions （length and thickness） on bending strength of T-shaped mor- tise and loose-tenon joints. Polyvinyl acetate （PVAc） and two-component polyurethane （PU） adhesives were used to construct joint specimens. The bending moment capacity of joints increased significantly with increased length and thickness of the loose tenon. Bending moment capacity of joints constructed with PU adhesive was approximately 13% higher than for joints constructed with PVAc adhesive. We developed a predictive equation as a function of adhesive type and loose tenon dimensions to estimate the strength of the joints constructed of oriental beech （Fagus orientalis L.） under uniaxial bending load.

关键词： bending moment capacity mortise and loose tenon loose tenon dimensions polyvinyl acetate two-component polyurethane

A feasibility study of using two-component polyurethane adhesive in constructing wooden structures

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Journal of Forestry Research 2014年第2期25卷 477-482页

作者： Mohammad Derikvand Ghanbar Ebrahimi Mehdi Tajvidi department of wood and paper Science and technology College of Agriculture and Natural ResourcesUniversity of Tehran

This investigation was conducted to determine the feasibility of using a two-component polyurethane （PUR） adhesive, with special waterproof properties, in constructing wooden structures. We designed and conducted tests to compare the shear strength and adhesion performance of PUR with polyvinyl acetate （PVAc） adhesive on block-shear specimens constructed of oriental beech （Fagus orientalis L.）, fir （Abies alba Mill.）, poplar （Populus deltoides Bartr.）, white oak （Quercus alba L.）, sycamore （Platanus orientalis L.） and white walnut （Juglans cinerea L.）. The values of the percentage of wood failure were also determined in specimens constructed with each adhesive. The highest shear strength values of both adhesives were obtained in specimens constructed of beech, while the lowest shear strength values were obtained in fir and poplar specimens. Average shear strength of the PUR adhesive was 16.5% higher than that of the PVAc adhesive. Specimens constructed of fir, poplar and sycamore were characterised by the highest percentages of wood failure, whereas the lowest average percentages of wood failure were obtained in beech and oak specimens. With the exception of oak specimens, there was no statistically significant difference between percentage of wood failure among the PUR and PVAc adhesives. Generally, the PUR adhesive showed an acceptable adhesion performance on wood materials used in our study.

关键词： wooden structures polyurethane adhesive polyvinyl acetate adhesive shear strength wood failure wood species

A multiple criteria analysis of factors affecting markets of engineered wood products with respect to customer preferences: a case study of particleboard and MDF

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Forestry Studies in China 2013年第1期15卷 61-69页

作者： Fatemeh SARFI Majid AZIZI Amin ARIAN department of wood and paper sciences and technology Faculty of Natural Resources University of Tehran

Of considerable importance and a principal goal in business is the creation of customer satisfaction. Evalu- ation of end user preferences for producers of particleboard and medium density fiberboard （MDF） requires indices for the assessment of markets and modification of product quality. However, only sporadic research has been carried out in this field. Therefore, the goal of this survey was to identify indices with respect to the points of view of： 1） consumers in order to select particleboard and MDF, 2） suppliers in order to consider production strategies, improve product quality, improve competitive ability of domestic producers in the market and help industry to be more customer oriented. This survey consisted of two stages. In the first stage, factors affecting customer preferences in the selection of particleboard and MDF were determined using a Delphi method, with the help of experts and a group of principal users of these prod- ucts. Then these factors were categorized in three groups： qualitative, technical and technological and marketing factors. Furthermore, questionnaires were prepared and distributed among consumers and responses evaluated and weighted by using an analytic hierarchy process （AHP） using expert choice software. Our results show that at both stages, the consistency ratio was less than 0.1, indicating that all results and judgments were stable and acceptable. The results obtained from questionnaires about particleboard rank the priorities for factors in the selection by consumers as follows： nail and screw holding ability, homogeneity in structure, edge strength of panel, durability and bending strength. The most important factors for MDF were machinability of panels, homogeneity in structure, nail and screw holding ability, edge strength of panel, durability and bending strength.

关键词： particleboard medium density fiberboard (MDF) customer satisfaction AHP market

Estimating the costs of one hectare of poplar planting and supplying wood required for producing various types of paper in Iran

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Forestry Studies in China 2013年第4期15卷 349-356页

作者： Majid AZIZI department of wood and paper sciences and technology Faculty of Natural Resources University of Tehran

In Iran, due to abundant restrictions on harvesting wood from northern forests by implementing the preservation project and also lack of possibility for sufficient wood production, development of the area of planting poplar is quite inevitable. Poplar wood properties have special importance to produce many wood production, particularly pulp and paper. paper factories are the major consumers of poplar wood at the global level and this is because of unique morphological, physical, mechanical and technological properties of poplar wood. Therefore, regarding the importance of using this species in making various printing and writing paper, packaging or carton, cardboard and newsprint, in this study, costs of poplar production in one hectare including planting and harvesting were examined and determined. Then, based on conversion coefficients of FAO, required round wood, productivity and the cost of poplar wood were calculated for the producing various kinds of paper. The results indicate that carton and cardboard paper or packaging allocate the lowest cost and highest return, while printing and writing paper had highest cost and lowest return in terms of poplar wood supply needed for paper production.

关键词： poplar packaging paper newsprint paper printing and writing paper planting conversion coefficient ,productivity

Effect of carbon nanotube on physical and mechanical properties of natural fiber/glass fiber/cement composites

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Journal of Forestry Research 2015年第1期26卷 247-251页

作者： Hamed Younesi Kordkheili Shokouh Etedali Shehni Ghorban Niyatzade School of wood and paper Science and technology Maziyar University department of wood and paper Science Faculty of Natural ResourcesTarbiat Modares University department of Chemistry Payam Noor University

The objective of this investigation was to introduce a cement-based composite of higher quality. For this purpose new hybrid nanocomposite from bagasse fiber,glass fiber and multi-wall carbon nanotubes（MWCNTs）were manufactured. The physical and mechanical properties of the manufactured composites were measured according to standard methods. The properties of the manufactured hybrid nanocomposites were dramatically better than traditional composites. Also all the reinforced composites with carbon nanotube, glass fiber or bagasse fiber exhibited better properties rather than neat *** results indicated that bagasse fiber proved suitable for substitution of glass fiber as a reinforcing agent in the cement composites. The hybrid nanocomposite containing10 % glass fiber, 10 % bagasse fiber and 1.5 % MWCNTs was selected as the best compound.

关键词： Cement hybrid nanocomposites Multi-wall carbon nanotubes Bagasse fiber Physical and mechanical properties

Finite element analysis of stress and strain distributions in mortise and loose tenon furniture joints

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Journal of Forestry Research 2014年第3期25卷 677-681页

作者： Mohammad Derikvand Ghanbar Ebrahimi department of wood and paper Science and technology College of Agriculture and Natural Resources University of Tehran

We studied the effect of loose tenon dimensions on stress and strain distributions in T-shaped mortise and loose tenon （M＆amp;LT） furni-ture joints under uniaxial bending loads, and determined the effects of loose tenon length （30, 45, 60, and 90 mm） and loose tenon thickness （6 and 8 mm） on bending moment capacity of M＆amp;LT joints constructed with polyvinyl acetate （PVAc） adhesive. Stress and strain distributions in joint elements were then estimated for each joint using ANSYS finite element （FE） software. The bending moment capacity of joints increased significantly with thickness and length of the tenon. Based on the FE analysis results, under uniaxial bending, the highest shear stress values were obtained in the middle parts of the tenon, while the highest shear elastic strain values were estimated in glue lines between the tenon sur-faces and walls of the mortise. Shear stress and shear elastic strain values in joint elements generally increased with tenon dimensions and corre-sponding bending moment capacities. There was consistency between predicted maximum shear stress values and failure modes of the joints.

关键词： bending moment capacity, failure mode, finite element,furniture, mortise and loose tenon joint stress and strain distributions

Analysis of factors affecting diagonal tension and compression capacity of corner joints in furniture frames fabricated with dovetail key

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Journal of Forestry Research 2013年第1期24卷 155-168页

作者： Mosayeb Dalvand Ghanbar Ebrahimi Akbar Rostampour Haftkhani Sadegh Maleki department of wood and paper Science and technology Faculty of Natural ResourcesUniversity of TehranKarajIran.

This study was conducted to analyze the effect of joint type, and numbers and types of dovetail keys on diagonal tension and compression performance of corner joints in a furniture frame. Joint members were cut from white fir lumber. Butted and mitered joints were constructed with one and two dovetail key（s） with butterfly and H shapes. Joints were glued by polyvinyl acetate （PVAc） and cynoacrylate （CA）. Compression capacity of joints was higher than diagonal tension. Mitered joints were stronger than butted ones. Butterfly dovetail keys were superior to H shape keys. Double keys performed better than single key. Experimental joints glued with PVAc were stronger than those glued with CA glue and control specimens. In terms of strength, butterfly dovetailed joints were comparable with doweled joints.

关键词： diagonal tension diagonal compression dovetail key joints lumber