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

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.

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

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.

The influence of silane coupling agent and poplar particles on the wettability, surface roughness, and hardness of UF-bonded wheat straw(Triticum aestivum L.)/poplar wood particleboard

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 particleboard 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 particles(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 system. 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.

Estimation of demand for wood panels in Iran by the year of 2012

Considering increasing rate of Iran population and consumption of wood panels, the authors investigated the per capita consumption of wood panels during the years from 1997 to 2007.The exponential smoothing method was used to obtain a per capita consumption pattern of wood panels in Iran for estimating demand of wood panels by the year of 2012.Results show that the consumption of particleboard, fiberboard, and medium density fiberboard in Iran will increase by 33%, 72% and 107 %, respectively, by the year of 2012;however, the consumption of plywood will increase only by 7% by 2012.The deficient amount of wood panels in Iran is estimated over 1400 000 m3.The results of this study provide the technique reference for planners of wood panel industries in Iran in capital investment decisions.

Determination of fiber length and juvenile and mature wood zones in Acer velutinum Boiss.trees grown in Iran

In our investigation we studied fiber lengths and the transition age from juvenile to mature wood in Acer velutinum Boiss. For this purpose, samples from three normal maple trees at a Noshahr site in northern Iran were selected. Disks were cut at breast height. Test samples were taken along a radial direction from the pith to the bark, accounting for every ring during a 48-year period. We used the Franklin method to distinguish between fibers of juvenile and mature wood. The results show that the fiber length increased along the radial direction from the pith to the bark. The transition age between juvenile and mature wood was determined at the 14th annual ring from the pith.

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

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.

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

We studied the effect of loose tenon dimensions on stress and strain distributions in T-shaped mortise and loose tenon(M&LT) furniture 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&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 surfaces and walls of the mortise. Shear stress and shear elastic strain values in joint elements generally increased with tenon dimensions and corresponding bending moment capacities. There was consistency between predicted maximum shear stress values and failure modes of the joints.

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

We determined the effects of adhesive type and loose tenon dimensions(length and thickness) on bending strength of T-shaped mortise 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.

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

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.

The effect of urea pretreatment on the formaldehyde emission and properties of straw particleboard

For manufacturing low-formaldehyde emission particleboard from wheat straw and urea-formaldehyde (UF) resins using urea treatment for indoor environments, we investigated the influence of urea treatment on the formaldehyde emission, physical and mechanical properties of the manufactured particleboard. Wheat straws were treated at three levels of urea concentration (5%, 10%, 15%) and 95℃as holding temperature. Wheat straw particleboards were manufactured using hotpress at 180℃and 3 MPa with two types of UF adhesive (UF-45,UF-91). Then the formaldehyde emission values, physical properties and mechanical properties were considered. The results show that the formaldehyde emission value was decreased by increasing urea concentration. Furthermore, the results indicate that the specimens under urea treatment have better mechanical and physical properties compared with control specimens. Also specimens under urea treatment at 10% concentration and UF-91 type adhesive have the most optimum physical and mechanical strength.

Bending moment resistance of corner joints constructed with spline under diagonal tension and compression

We determined the effects of the penetration depth and spline material and composite material type as well as joining method on bending moment resistance under diagonal compression and tension in common wood panel structures. Composite materials were laminated medium density fiberboard (MDF) and particle board. Joining methods were buttand miter types. Spline materials were high density fiber board (HDF).The penetration depths of plywood, wood (Carpinus betolus) and splinewere 8, 11 and 14 mm. The results showed that in both diagonal compression and tension, MDF joints are stronger than particle board joints,and the bending moment resistance under compression is higher compared with that in tension. The highest bending moment resistance under tension was shown in MDF, butt joined using plywood spline with 8 mm penetration depth, whereas under compression bending moment resistance was seen in MDF, miter joined with the HDF spline of 14 mm penetration depth.

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

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.

Water-repellent efficiency of thermally modified wood as affected by its permeability

This study shows how the air permeability of thermally modified wood contributes to its water-repellent efficiency. For this purpose, freshly cut boards of hornbeam(Carpinus betulus), poplar(Populus nigra), and heartwood of oak(Quercus castanifolia) were modified at a steam temperature of 180 °C for 3 h inside a Thermo Wood kiln.The porous structure, permeability, and water uptake of wood were affected differently by thermal modification,depending on the wood species. The creation of microcracks in the cell walls, due to collapsing of fiber cells,resulted in a noticeable increase in the permeability of hornbeam. Despite checking in the poplar wood structure,its permeability was negatively affected by thermal modification. In contrast to oak and poplar, a negative waterrepellent efficiency was observed for the modified hornbeam, caused by an increase in the permeability.

A Review on Date Palm Tree:Properties,Characterization and Its Potential Applications

Date palm(phoenix dactylifera),which is mostly found in the middle east countries such as Iran,Iraq,Saudi Arabia,and the United States(California)that play a significant role in the economical and the environmental condition in those areas.The main purpose of planting dates is its fruit,which is consumed as fresh,dried or processed forms.There are approximately 100 million date palm trees in the worldwide that 62 million of these trees located in the Middle East and North Africa.In Saudi Arabia only,15000 tons of date palm leaves is prepared as waste materials.The leaves of date palm tree are used in several applications such as making ropes,baskets,and mats in many parts of the world.Unfortunately,the huge amount of the non-food products from the date palm remains as landfill materials without any specific usage.By attention to the date palm properties,the literature clearly showed that each part of date palm has great potential to be used for a variety of applications such as:making paper,absorption of heavy and toxic metals,energy production and soil fertilizing.Some of the obstacles and solutions for using palm date in these applications were also explored.Considering these issues and their solutions,the date palm is a favorable alternative.Despite some limited and traditional uses of these palm wastes,this review considered date palm applications and the properties’of the most important part of that tree in recent researches and related issues for future research are also spotted.

Bending moment resistance of dowel corner joints in case-type furniture under diagonal compression load

We investigated bending moment resistance under diagonal compression load of corner doweled joints with plywood members. Joint members were made of 11-ply hardwood plywood of 19 mm thickness. Dowels were fabricated of Beech and Hornbeam species. Their diameters(6, 8 and 10 mm) and depths of penetration(9, 13 and 17 mm) in joint members were chosen variables in our experiment. By increasing the connector's diameter from 6 to 8 mm, the bending moment resistance under diagonal compressive load was increased, while it decreased when the diameter was increased from 8 to 10 mm. The bending moment resistance under diagonal compressive load was increased by increasing the dowel's depth of penetration. Joints made with dowels of Beech had higher resistance than dowels of Hornbeam. Highest resisting moment(45.18 N·m) was recorded for joints assembled with 8 mm Beech dowels penetrating 17 mm into joint members Lowest resisting moment(13.35 N·m) was recorded for joints assembled with 6 mm Hornbeam dowels and penetrating 9 mm into joint members.

Gypsum-bonded particleboard manufactured from agricultural based material

Gypsum-bonded particleboard(GBPB) panels were made from various mixtures of particles of bagasse(Saccharum officinarum L.) and wheat straw(Triticum aestivum L.), bonded with different ratios of particle/gypsum. This study examined the feasibility of bagasse and wheat straw particles in the production of GBPB. One-layer experimental GBPBs with a density of 1.05 or 1.20 g·cm 3were manufactured at different ratios of bagasse/wheat straw, i.e., 100%/0%, 93.75%/6.25%, 87.5%/12.5%, 75%/25%, 50%/50%, 25%/75% and 0%/100% using two particle/ gypsum composite ratios, i.e., 1/2.75 and 1/3.25 by weight. Thickness swelling(TS), water absorption(WA), modulus of rupture(MOR), modulus of elasticity(MOE) and internal bond strength(IB) properties of the boards were evaluated and a statistical analysis was performed in order to examine the possible feasibility of these agricultural residues for use in commercial GBPB manufacturing. We determined that WA of panels decreases as the amount of straw increases to 100% and the LR/G(wood/gypsum) ratio decreases to 1/3.25, whereas the TS of panels decreases as the proportion of straw decreases to 0% and the LR/G ratio increases to 1/2.75. The experimental results also show that the MOR and MOE of panels containing 0%, 6.25% and 12.5% wheat straw with a LR/G ratio of 1/2.75 were higher than those of panels made from 25%–100% wheat straw with a LR/G ratio of 1/2.75, as well as those from all other percentages of straw with a LR/G ratio of 1/3.25. On the other hand, the IB of panels containing more than 12.5% straw with LR/G ratios of 1/2.75 and 1/3.25 were lower than those of panels made from 0–12.5% straw also with both LR/G ratios. Panels consisting of 0%, 6.25% and 12.5% wheat straw with LR/G ratios of 1/2.75 and 1/3.25 met the minimum EN standard requirements of mechanical properties for general purposes. All of the panels containing 0–100% wheat straw with a LR/ G ratio of 1/2.75 or 1/3.25 met the required level of TS for 24-h immersion.

2012年伊朗人造板需求量预测

鉴于伊朗人口和人均人造板消耗量的增加，本研究调查了11年间（1997～2007）的人均人造板消耗量。为估算和预测到2012年伊朗的人造板需求量，利用霍尔特指数平滑方法分析获得伊朗人均人造板消耗量模式。结果表明：到2012年，在伊朗刨花板，纤维板和中密度板材消耗量将分别增加33％，72％和107％，而胶合板需求量仅增加7％。人造板需求量的缺口将会达到1400000m^2。因此，对2012年伊朗的人造板需求量的估算和预测的研究结果，为扩大目前的伊朗人造板需求量提供了科学基础。表6参11。

Constitutive expression of codon optimized Trichoderma reesei TrCel5A in Pichia pastoris using GAP promoter

To address the deficient activity of TrCel5A in naturally secreted cellulase preparation,this study used the GAP promoter to induce constitutive expression of Trichoderma reesei TrCel5A in Pichia pastoris.A recombinant TrCel5A was screened out after gene optimization,synthesis,and expression.The biochemical and enzymatic properties of the new recombinant were characterized.As a result,optimization of shake-flask fermentation of the recombinant was obtained at 28℃,2%inoculum volume,an initial pH of 6.0,as well as glycerol and Tween-80 additions of 30 g/L and 6 g/L,respectively.Under the above-optimized conditions,the recombinant produced 14.8 U/mL of the enzyme activity at 96 h of fermentation.To further enhance enzyme production,pilot-scale cultivation was evaluated using 5-L bioreactors.Using high-cell-density fermentation,the recombinant strain increased enzyme activity to 130.4 U/ml and protein content to 2.49 g/L.In addition,the kinetic factors,including K_(m) and V_(max) values for TrCel5A,were detected to be 5.1 mg/mL and 265.9μmol/(min.mg),respectively.Thus,TrCel5A was effectively expressed in P.pastoris under the GAP promoter,and it demonstrated its potential in commercially relevant enzyme hydrolysis of lignocellulosic biomass.