Volume 14 Issue 1

Various natural products are potentially suitable for wood protection, particularly against fungi attack. Caffeine is a well-known compound of natural origin, commercially and economically available, which could facilitate its future use for wood protection. This work investigated the antifungal resistance of the sapwood of Scots pine (Pinus sylvestris L.) treated with a water solution of caffeine and then thermally modified. The samples after impregnation were thermally modified at different temperatures selected on the basis of thermogravimetric analysis (TGA) of caffeine. The paper presents preliminary results of resistance of treated pinewood towards Aspergillus niger van Tieghem (ATCC 6275). The treated samples were subjected to both a leaching procedure and to the artificial aging procedure imitating natural weather conditions. Thermal modification of wood treated with caffeine improved the fungistatic properties of samples after artificial aging. It occurred through partial elimination of caffeine leaching from the wood structure.

Peanut shells were liquefied in phenol using sulfuric acid as the catalyst. The effects of the liquefaction conditions, such as the phenol/peanut shells ratio, catalyst loading, reaction temperature, and time, on the residue ratio, percent combined phenol, and formaldehyde reactivity of the liquefied products were investigated. The results showed that increasing the phenol/peanut shells ratio decreased the residue ratio and increased the combined phenol and formaldehyde reactivity. Increasing the catalyst loading decreased the residue ratio and increased the combined phenol, but a higher catalyst loading caused the formaldehyde reactivity to decrease. A higher reaction temperature and prolonged reaction time did not lead to a further decrease in the residue ratio and it further increased the combined phenol and formaldehyde reactivity. Fourier transform infrared spectroscopy and gas chromatography-mass spectroscopy showed that the liquefied products contained a large amount of polyphenol compounds and a small quantity of furan compounds and furfural. The SEM images showed small particles were the main portion of the liquefaction products and cellulose fibers could still be clearly seen.

Different bleaching reagents have different efficiencies of removing chromophore groups from chemical pulps. The objective of this work was to evaluate the effect of different bleaching sequences on the removal of chromophore groups, especially carbonyls, which are suspected to cause brightness reversion. The bleaching sequences analyzed comprise the stages: chlorine dioxide, acid hydrolysis at high temperature, alkaline extraction with hydrogen peroxide, pressurized hydrogen peroxide, and hydrogen peroxide. After bleaching an oxygen-delignified eucalypt kraft pulp with these sequences, the pulps were analyzed for their final brightness, brightness reversion, and pulp viscosity; the bleached pulps were also analyzed using ultraviolet resonance Raman spectroscopy in the infrared region. The infrared analysis indicated that bleaching stages that used hydrogen peroxide, such as pressurized hydrogen peroxide or hydrogen peroxide, in the terminal position reduced the amount of carbonyl groups in the bleached pulp as measured by the absorption band intensity. This study observed that the inclusion of a hot acid hydrolysis stage in the bleach sequence improved the final brightness and brightness stability of the bleached eucalyptus pulp. The replacement of a chlorine dioxide brightening stage by a hydrogen peroxide stage at the end of a bleach sequence yielded higher pulp brightness, and less brightness reversion. The use of pressurized hydrogen peroxide with oxygen resulted in less brightness reversion.

Recently the accessibility of sago biomass has drawn considerable interest in research regarding the production of renewable energy. In this study, sago-derived biochar was evaluated and characterized as a solid fuel. Sago biochar was produced in an electric fluidized bed reactor at temperatures between 300 °C to 600 °C, with nitrogen flow rates of 50 mL/min to 100 mL/min for 10 to 30 min of process. The optimum condition to ensure the maximum biochar yield (47%) were obtained at 400 °C, 20 min of process and of 75 mL/min of nitrogen flow. The physicochemical properties of the final product were determined through thermogravimetric analysis (TGA), scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), and elemental analysis techniques. The higher heating value (HHV) of the material was remarkably improved by almost 13% via pyrolysis. The experimental results showed that sago biomass can be considered a suitable source of solid fuel, especially in the industrial and domestic sectors in Sarawak, Malaysia.

This paper explores the impact of daylit wooden environments on human perception and well-being. Several studies have shown that the use of wood in furniture, interior surfaces, and decoration helps create warm, bright, and pleasant ambiences, enhancing psychological well-being and comfort when compared to other materials. The main objective of this research was to assess the effects of different colors, finish, and ratio of wooden surfaces combinations on human perception. More specifically, participants compared simultaneously five different interior wooden scale models of room environments under the natural light of the northern hemisphere in terms of their appreciation, visual comfort, and well-being. The survey involved 80 participants with an exploratory questionnaire in order to compare and classify the different models. Conclusions showed a preference for clear, bright, and warm models for cognitive and small-scale tasks. Darker models in terms of reflectance and lighting ambiences were the least preferred, especially for women.

The effects of TiO2 (titanium dioxide) loading were evaluated relative to mechanical, thermal, and surface properties of the wood-plastic nanocomposites (WPNs). Pine wood flour, mixed with maleic anhydride polypropylene (MAPP), TiO2 nanoparticles (0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, and 5 wt%), and polypropylene, was compounded in a twin screw co-rotating extruder. The mass ratio of the wood flour to polypropylene (PP) was 50/50 (w/w) in all compounds. Test specimens were produced using injection molding machine from the pellets. Flexural and tensile properties, thermogravimetric analysis, surface roughness, wettability, and morphology of the manufactured nanocomposites were evaluated. Flexural and tensile properties of the wood-plastic nanocomposites increased with the increasing content of the TiO2. The surface roughness of the wood-plastic nanocomposites was reduced by increasing the content of TiO2. Increasing the loading of TiO2 increased the amount of residual ash and thermal stability.

To enhance effective wood utilization, knowledge of the anatomical features that impact its service behavior is indispensable. The anatomical features of branchwood and stemwood of Betula costata Trautv. from natural secondary forests in central (Muzhaling mountain) and northeast (Maoershan mountain) China were studied to provide adequate information to enhance their efficient utilization, especially branchwood, whose use could widen the raw material base of the timber industry. Microtomed sections were employed to determine the tissue dimensions and proportions. Analyses of variance were used to test the anatomical feature differences between the two different sites, between the stemwood and branchwood, and between the heartwood and sapwood. The results showed that B. costata wood is diffuse-porous with more but narrower vessels located in the branch than in the stem. The branchwood also had a significantly higher fiber proportion than the stemwood. The sapwood exhibited significantly longer fibers than the heartwood. B. costata from Maoershan had significantly longer fibers, lower fiber proportions, larger fiber lumen diameter, and higher vessel density than that from Muzhaling. The results suggested that B. costata branchwood from Maoershan is suitable for papermaking and glued plates, while stemwood can be used for light construction purposes.

Symbiotic bacteria in the termite gut system may play an important role in lignin degradation that can assist the subsequent saccharification process. Pseudocitrobacter anthropi MP-4, which is capable of degrading lignin components and rapidly growing on various lignin analogue dyes, was successfully screened from the gut of a wood-feeding termite Microtermes pakistanicus. Further decolorization tests with this strain showed that the strain MP-4 potentially produced some relevant extracellular enzymes to participate in lignin degradation. The removal rate of chemical oxygen demand by this strain was recorded as high as 52.1% when it was incubated in a mineral-salt medium with lignin as the sole carbon source. For the degrading process of MP-4 on lignin, it was proposed through a series of evaluations by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and pyrolysis gas chromatography/mass spectroscopy, that the lignin degradation mechanism of the strain MP-4 would primarily include the cleavage of various chemical linkages and the demethylation reactions. This resulted in a change in the S/G ratio and the disappearance of the biphenyl structure in the lignin components. Thus, these findings suggested that the strain MP-4 uniquely presented an attractive capability to deconstruct lignin components from biomass, which may be potentially valuable for a future industrial exploration.

The synergistic effect of hierarchically porous zeolites on the fire retardancy and fire toxicity of ammonium polyphosphate (APP) treated wood composites was studied in this work. Hierarchically porous 4A (H4A) zeolite and 4A zeolite were hydrothermally synthesized and characterized. Several groups of wood composites containing APP as fire retardant and H4A/4A zeolites as synergists were fabricated. Thermogravimetric (TG) results showed that H4A zeolite increased the char formation and enhanced the thermal stability of APP treated wood at higher temperature. Cone calorimetry test results suggested that H4A zeolite reduced the heat release rate (HRR) and decreased CO produce rate (COPR) of APP treated wood composites. Moreover, H4A also exhibited better smoke suppression than 4A zeolite when the APP content was small. These results demonstrated that H4A zeolites may be a promising synergistic component for improving the fire retardancy and reducing the fire toxicity of APP treated wood composites.

The goal of this study was to develop a lumber grade yield prediction model with a probability-based technique known as the Monte Carlo simulation. The data to develop the prediction model was taken from an existing lumber grade yield database developed from red oak logs sawn at the Appalachian region of the United States. Statistical input analysis techniques were used to fit the lumber grade yields to hypothesized probability distributions. Inverse cumulative probability function distributions were developed from the fitted probability distributions to simulate and predict lumber grade yields. The predicted gross revenue was compared with the actual gross revenue and against the gross revenue predicted by a multiple linear regression (MLR) model. The predicted gross revenue using the Monte Carlo simulation had a 0.88% absolute error compared with the actual gross revenue, while the predicted gross revenue from the MLR model had an absolute error of 3.31%. The higher prediction power of the Monte Carlo method was more effective when predicting lumber grade yields from individual log groups. The Monte Carlo model developed in this research can be easily implemented to quickly predict lumber grade yields or gross revenue to support procurement, log inventory management, production, planning, and marketing operations.