Volume 15 Issue 4

Some negative attributes of wood material have numerous practical consequences. The most important of these attributes is that wood, as a hygroscopic material, is dependent on the relative humidity of its environment. The hygroscopic nature of wood material can lead to serious problems when used in doors, windows, and interior or exterior decoration materials. The aim of this study was to evaluate the effect on wood materials equilibrium moisture due to different climates in selected provinces in Turkey. This study examined pine (Pinus sylvestris L.) and oak (Quercus rubra L.) woods, both of which are commonly used in industry. Over 12 months, the equilibrium moisture value of these wood was determined in the Bursa, Antalya, İzmir, Malatya, Trabzon, Karabük, Van, and Kars provinces of Turkey. Pine and oak samples, prepared per standards TS 2471 (1976) and TS 2472 (1976), were taken from these provinces each month, and the equilibrium moisture values were determined. It was observed that the use of Scotch pine wood samples for both indoor and outdoor use was more appropriate over the 12-month period. Malatya was the province in which the Scotch pine samples were the least affected. It was also determined that Van was the most suitable province for the interior use of oak wood material. It was not found that indoor use gave better results than outdoor use.

Leucaena leucocephala (Lam) de Wit is a fast-growing tree species often used as lead (shade) tree that can be cultivated in Malaysia. This species has potential as an alternative resource for the Malaysian furniture and panel board industries in the coming years because of a shortage of the current frequently used raw material (rubberwood). A study on growth performance and potential as particleboard resource material was done. In terms of growth performance, the preliminary study indicated that Leucaena trees grew at a rate of 44% from the first month to the forth month and 43% from 6 to 12 months. As for particleboard manufacturing, Leucaena: Rubberwood admixture bound with urea formaldehyde (8%, 10%, and 12% resin content) to a density of 700 kg/m3, showed promise of usability when all boards pass the Type P2 board requirement of EN312:2010. In general, L. leucocephala wood is a potential raw material for the manufacture of wood composites.

Using Modelica language, a mathematical model combining static and dynamic contributions of the dense phase region of a 130 t/h biomass circulating fluidized bed boiler combustion system was established on MWorks simulation platform. The mathematical model adopted modular packaging to increase the universality of the model, and it used an implicit, high-order, and multi-step Dassl integration algorithm to conduct the simulation. Under the design condition parameters, the relative error between the bed temperature of the dense phase region obtained by the simulation model and the actual temperature was less than 3.8%, which indicated that the static characteristics of the established simulation model were accurate. The effects of biomass feed and primary air volume step changes on the bed temperature, oxygen content in the flue gas, height of the dense phase region, and the bed pressure difference in the dense phase region were investigated. Both the biomass feeding and the primary wind step of 10% reduced the temperature, and it was obvious that the primary wind had a greater impact on the bed temperature. Meanwhile, the primary wind had a greater impact on the bed pressure difference than the biomass feeding.

Ordinary kraft pulping of bagasse was adjusted by utilizing green liquor at the laboratory and research of Misr-Edfu Pulp, Writing and Printing Paper in a small pilot batch digester (Edfu, Aswan, Egypt) as an environmentally friendly method. Bagasse pulp was produced with and without green liquor, and the physical and mechanical properties of unbleached bagasse were assessed. The parameter states of cooking were completed utilizing antacid substance charge from 10% to 13%, cooking temperature from 160 to 170 °C, cooking time from 20 to 50 min, and solid to liquor ratio of 7:1 that was steady in all preliminaries. The results demonstrated the exploratory idea that green liquor can provide critical pulping advantages in comparison with customary kraft pulping. Screened pulp yield improved 2.6%, rejects content decreased 0.9%, kappa number was reduced by 26.9%, and brightness was increased by 3%. There also was improved mechanical quality of bagasse pulp: increases of 14.3% (tensile index), 8.7% (tear index record), 4.6% (burst index), and 15.4% (double fold number) were observed compared with conventional kraft pulping. This process also saved money related to the expense of depleted vitality, lime consumed during causticizing process, and upkeep of the causticizing plant.

Several physical and mechanical properties can characterize tissue papers. In particular, low grammage but high values of bulk, flexibility, liquid absorption capacity, and softness are common properties for tissue papers. These properties must be adapted to meet the requirements of the final consumer, which can vary greatly in different countries. This work resulted from a study regarding the impact of two different stacking sequences of 5-ply toilet paper with configurations 1 and 2 (deco:micro embossing of 3:2 and 2:3 plies, respectively), which had the same base tissue papers in each mother reel, on their mechanical behavior and absorption capacity. The stacking sequence of the plies influenced the properties of the finished toilet paper. For configurations 1 and 2, after the embossing process, bulk increases of 46% and 40%, respectively, and water absorption capacity increases of 2% and 17%, respectively, were registered. In this case, the bulk increase was not the key property that influenced the water absorption capacity. Regarding mechanical properties, both configurations showed a higher negative impact caused by the deco embossing. For commercial purposes and to adhere to the final consumers’ preferences for toilet paper, configuration 1 was more suitable for mechanical strength, and configuration 2 was more suitable for absorption capacity.

Three enzymes, mannanase, xylanase, and cellulase, were applied for hydrolysis of thermomechanical pulp (TMP) primary discharge prior to PFI refining, aiming to study the effect of enzymatic hydrolysis on the required number of PFI revolutions. The quantity of reducing sugar was used as an indicator for enzyme hydrolysis efficiency. Then, under the optimized enzyme loading, treated and un-treated pulp were refined with different PFI revolutions. Subsequent fiber characteristics, such as fiber length and fines content were examined. Under the optimized enzyme loadings and a given 20000 PFI revolutions, in comparison with the control pulp, mannanase and xylanase pre-treatment could save PFI refining revolutions by 20% and 25%, respectively. There was no significant energy savings for the cellulase-treated pulp. During the hydrolysis, the enzyme broke down TMP fibers into shorter pieces and yielded more fines than the control pulp. Among the three enzymes, cellulase showed the highest efficiency in fiber breakdown, mannanase in the middle, xylanase the lowest. Longer hydrolysis time (more than one hour) had no evident effect on the pulp freeness reduction and reducing sugar production. Among the three enzymes, under the optimized enzyme loading, cellulase was the most efficient for enhancing production of reducing sugars.

To reduce the density of bamboo-based concrete formwork on the premise of meeting the performance requirements, the bamboo was first treated by cold plasma, and then by increasing the distance between the adjacent bamboo strips of the radial bamboo curtain in the middle layer, the internal porosity was increased. The production of lightened bamboo based concrete formwork, which meets China’s forestry industry standards, was achieved. Four groups of bamboo-based concrete formworks with different slab structures were designed. The key results showed that slab structures have an extremely significant effect on the density, MOR, MOE, IB, and TS of the bamboo-based concrete formwork. A group of optimal slab structures was obtained by comparing their physical and mechanical properties (1st and 9th floor-phenolic resin impregnated paper, 2nd and 8th floor-bamboo mat, 3rd and 7th floor-tangential bamboo curtain, 4th and 6th floor-radial spaced bamboo curtain). Based on the required physical and mechanical properties, its density was 0.62 g·cm-3, which was 27.1% lower than that of traditional bamboo plywood template (0.85 g·cm-3) circulating on the current market. This lightened BBCF can save raw materials, facilitate transportation and reduce labor intensity in the application process so that it will be widely used in building construction.

A wood-based composite exhibiting excellent electromagnetic shielding performance was prepared by electroless Ni plating. The properties of the material were characterized by a series of tests. The results showed that the growth route of Ni particles was first arranged along the inherent grain of the wood to form a banded metal layer. With extension of the duration of electroless plating, the growth of Ni particles gradually extended around and filled the pores between wood fibers, and finally formed flake-shape structure. The metal coatings formed a strip along the inherent grain of the wood surface and then changed into a sheet until it covered the entire wood surface. The coatings resistance was from 12 Ω to 0.5 Ω with the increase in duration of electroless plating. When the duration was 20 min, the composite coating resistance was 0.5 Ω. Here, the contact angle of composite coatings was 98.3° when the plating time was 15 min. When the wood surface was modified via two depositions of Ni, the average electromagnetic shielding value of the composites was over 80 dB in the frequency ranging from 0.3 kHz to 3.0 GHz.

Microalgae were isolated, identified, and cultivated for enhanced biomass production and lipid accumulation. A marine microalgae was isolated from coastal rock pools of Tuticorin, Tamil Nadu, and identified as Nitzschia sp. RRSE2 upon microscopic examination and molecular sequence analysis. The experimental results showed that the maximum growth, biomass, and lipid content were obtained at pH 8 using the F/2 medium. These parameters revealed a notable difference when NaCl was added at 3% concentration. Meanwhile, the nutrients NaNO3 (18.75 mgL-1) and NaH2PO4 (3.48 mgL-1) were shown to be suitable nitrogen and phosphorus sources, respectively, for the production of lipids. On day 14, the maximum lipid concentration of 77.5 mgL-1 was produced using optimized culture conditions. Additionally, the maximum number of 17×105 cells mL-1 and the biomass concentration of 0.69 gL-1 were achieved on this same day. Finally, the fatty acid composition of the algal lipid was analyzed by gas chromatography/mass spectrometry (GC/MS) analysis.

The effect of short-term thermomechanical (STTM) densification on shear strength of plywood produced with Scots pine (Pinus sylvestris L.) veneers was investigated. The veneer sheets were densified under temperatures of 20 °C, 120 °C, and 180 °C, and pressure of 1 MPa for 2 min. There were four polyvinyl acetate (PVAc) adhesives, 1 emulsion polymer isocyanate (EPI)-adhesive, and 2 resins for comparison reasons applied. The samples were stored for 7 d under the normal climate temperature of 22 °C and relative humidity of 65%. As a result of STTM densification, the plywood had higher density but lower shear strength. The plywood made with these veneers and EPI-adhesives showed the highest shear strength values. There was a slight difference of the final product’s shear strength between the used adhesives, but it was not noticeable in tested conditions.