Research Articles

Compression properties in three orthotropic directions for some important Turkish wood species, including Calabrian pine (Pinus brutia Ten.), Taurus cedar (Cedrus libani), Oriental beech (Fagus orientalis), and sessile oak (Quercus petraea), were studied using non-destructive and destructive techniques. The materials used in the study consisted of 720 small clear specimens of nominal dimensions of 20 x 20 x 60 mm. The influence of equilibrium moisture content (EMC) was studied over four batches of 15 specimens each, conditioned for six to eight weeks before testing at a temperature of 20 ± 2 °C and at four different relative humidity conditions (50%, 65%, 85%, and 95%). Time of flight values were measured with a commercial ultrasonic tester. Using the time results from the ultrasound device, the wave velocities (length/time) and Edyn values were calculated. Samples were also tested in uniaxial compression to determine the Young’s modulus and compression strength values in three orthotropic directions. The Edyn correlated well with the Young’s modulus and compression strength of the specimens; coefficients of determination ranged between 0.75 and 0.96. Moisture content seems to have more influence than density on sound velocities. Results showed that there is a weak and mostly negative correlation between the density of the specimens and the sound velocity values.

A better understanding of saw-chain cutting mechanics is needed for more efficient chainsaw designs. The effects of varying key parameters such as workpiece moisture content, workpiece density, cutting velocity, and depth-of-cut, while established for other types of cutting, are largely unexplored and/or unpublished for saw chains. This study contributes to filling this gap through experimentation and analysis. Experiments were conducted using a custom-built saw-chain testing apparatus to measure relevant forces over a range of workpiece moisture contents, workpiece densities, cutting velocities, and depths-of-cut. Analysis consisted of fitting linear regression models to experimental data, identifying trends, and exploring optimum cutting conditions. Results showed that over the range of values included in the study, workpiece moisture content and density had effects that depended on the depth-of-cut. Cutting velocity had a small effect, and depth-of-cut had a large effect. All trends fit well with linear models; however, depth-of-cut required one linear fit for small-to-mid values and a second fit for mid-to-large values. Maximum efficiency was found to occur at a depth-of-cut equal to the transitional value between fits. These results provide basic relationships that can lead to the more effective and efficient use and design of chainsaws.

The synergistic effect of two fire retardants, a Si-Al compound and chlorinated paraffin, was tested on ultra-low density fiberboards (ULDFs). To further understand the mechanism of fire retardancy, morphologies of unburned and burned ULDFs were studied using a scanning electron microscope with energy dispersive spectroscopy. It was found that as the volume of the burned ULDFs shrank, some crevices appeared. In addition, less fly ash formed on the top of specimens, and more bottom ashes remained in the original framework, with a clear network of structure built by the fibers. Carbon was almost absent in the fly ash; however, the weight ratio of C in the bottom ashes reached the maximum (> 43%) of the composition. Oxygen, Al, and Si appeared to have varying weight ratios for different ashes. Oxygen content increased with increasing Si and Al contents. Furthermore, Cl sharply decreased to less than 1% after combustion. Therefore, upon combustion, it was found that almost all of the substances in ULDFs, except for the Si-Al compound, were pyrolyzed to volatile carbon oxides and Cl compounds, especially the fly ash and lightweight C compounds.

This study was conducted to evaluate the possibility of utilizing kenaf (KNF) in LLDPE/PVOH to develop a new thermoplastic composite. The effect of KNF loading on the processability and mechanical, thermal and water absorption properties of linear low-density polyethylene/poly (vinyl alcohol)/kenaf (LLDPE/PVOH/KNF) composites were investigated. Composites with different KNF loadings (0, 10, 20, 30, and 40 phr) were prepared using a Thermo Haake Polydrive internal mixer at a temperature of 150 °C and rotor speed of 50 rpm for 10 min. The results indicate that the stabilization torque, tensile modulus, water uptake, and thermal stability increased, while tensile strength and elongation at break decreased with increasing filler loading. The tensile fractured surfaces observed by scanning electron microscopy (SEM) supported the deterioration in tensile properties of the LLDPE/PVOH/KNF composites with increasing KNF loading.

The ultrafiltration membrane reactor, utilizing a membrane module with a suitable molecular weight alleyway, retains the larger cellulase components. Smaller molecules, such as the fermentable reducing sugars and water, pass through the membrane. The purpose of this work was to investigate the capability of recycling cellulase in the UF membrane. PS30 hollow fiber membrane, an ultrafiltration method using internal pressure, was found to be an ideal membrane separation device, allowing re-use of the enzyme. A Box-Behnken experimental design (BBD) established the following optimum pretreatment parameters: operation pressure at 1.73 bar, temperature at 36.38 °C, and a pH of 5.92. Under these conditions, the model predicted a membrane flux yield of 2.3174 L/(m2•h). The rejection rate of the UF membrane was over 95%.

Value added manufacturing activity in the wood sawmilling industry of Peninsular Malaysia is important for employment opportunities, particularly for low income citizens living in this rural area, to provide returns to the local economy while being environmentally sustainable. This paper is a review on the value added wood sawmill industry in Peninsular Malaysia, using the value of major import and exports of major timbers products and forested area in Peninsular Malaysia over the period 2003 to 2012. The productivity performance measures that are based on the concept of value added are emphasized in this paper. The value added in wood sawmill industry was found to increase from year 2003 to 2012. Consequently, Malaysia is moving on the right path to achieve the goal of National Timber Policy 2020, transforming the timber industry into high value addition industry. However, further analysis using the value added productivity measure found that the value addition rely on international timber price rather than skilled workers.

In this work, lignin polyols were prepared from the liquefaction of kraft lignin and from the direct liquefaction of Elaeis guineensis lignocellulosic waste. The liquefaction reaction was performed with polyhydric alcohols using sulfuric acid as catalyst at 160 °C. The physical and chemical characterizations of lignin and lignin polyols were conducted by elemental analysis, Fourier transform-infrared spectroscopy, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, molecular weight distribution, and thermogravimetric analysis (TGA). Quantitative 13C NMR showed that all aliphatic hydroxyl group values of polyols noticeably increased with the use of the two methods compared to kraft lignin. The average molecular weight analysis of the liquefied product showed that it exhibited high molecular weight compared to kraft lignin. Both structural and thermal characteristics suggest that lignin polyols would be a good substitute for kraft lignin in the synthesis of polymeric compounds such as environmentally friendly resins or wood adhesives, as it presents higher amounts of activated free ring positions, higher molecular weight, and high thermal stability.

Eichhornia crassipes (water hyacinth) is an invasive weed that causes serious issues for rivers, lakes, and other reservoirs around the world, although it can be an excellent source for bioactive compounds such as phytosterols and some steroids found in many plants. In this study, water hyacinth samples from both Durango and Distrito Federal in Mexico were collected. Ascendant extracts (cyclohexane, hexane, acetone, and methanol) from their leaves, stems, and roots were analyzed. Using boron trifluoride (~10% [~1.3 M] in 1-butanol), all extracts were derivatized. Twenty-four derivatized samples were analyzed using a gas chromatography-mass spectrometry (GC/MS) method. Twenty carboxylic acids were found, as well as squalene, which was found in nine extract samples: four cyclohexane extracts, one hexane extract, three acetone extracts, and two methanol extracts. A compound not reported before, b-stigmasterol, was identified on three hexane extracts, an acetone extract, and a methalonic extract. Spirostane in acetone root extract and cholestane in cyclohexane stem-leaf extract were also identified.

The effects of pH and sulfonated lignin (SL) on the saccharification of enzymatic hydrolysis were investigated using acid bisulfite (AS)- and green liquor (GL)-pretreated poplar as substrates. The enzymatic sugar conversions of AS- and GL-pretreated poplar could reach high levels at pH 4.8. The sugar conversions of both AS- and GL-pretreated poplar solids increased when hydrophilic SL was used as an additive in the enzymatic hydrolysis. With SL addition, the optimal pH of AS-pretreated poplar moved to 5.1–5.7, while that of GL-pretreated poplar showed no significant difference. The sugar conversions of AS- and GL-pretreated poplar went up and then leveled off with SL charges from 0.05 to 0.3 g/g-substrate. The highest total sugar conversions increased from 76.4% and 86.9% (pH 4.8, without SL) to 83.5% (pH 5.4, SL 0.3 g/g-substrate) and 90.9% (pH 5.0, SL 0.2 g/g-substrate) for AS- and GL-pretreated poplar, respectively.

Unbleached kraft bamboo pulp was pretreated by a xylanase and laccase (X/L) treatment, as well as a joint treatment of X/L and alkali, prior to element chlorine free (ECF) bleaching. In comparison with the control test, the joint treatment of X/L and alkali (X/L+0.1%) had more potential to reduce absorbable organic halide (AOX) levels (29.79%) and COD content (21.55%), in addition to improving bleached pulp properties (56.88% decrease in kappa number and 8.94 %ISO increased in brightness). Moreover, the treatment of X/L+0.1% removed more lignin and HexA than X/L treatment. The analysis of XPS indicated that the X/L treatment could noticeably remove the surface lignin of pulp, but the joint treatments of X/L and alkali could promote the production of superficial lignin. FTIR results showed that pretreatments only reduced part of the lignin and carbohydrate contents, but did not change their structures. The joint pretreatment of enzymes and diluted alkali (X/L+0.1%) had more appealing advantages to produce bleached kraft bamboo pulp.