Volume 12 Issue 3

Bamboo residue was treated with an active oxygen (O2) and solid alkali (MgO) (CAOSA) process, which was developed recently by the authors owing to its environmentally friendly and high-efficiency characteristics. During the cooking process, 93.0% of lignin and 62.1% of hemicellulose were removed from the raw material, which resulted in a cellulose-rich pulp. This indicated that this cooking process is efficient to fractionate the bamboo residue into cellulose, hemicellulose, and lignin as a pretreatment for biomass conversion. The structural features of the hemicellulose from the pretreated bamboo residue were analyzed for comparison with that of the raw materials. The molecular structure of the hemicellulose fractions obtained from both the raw bamboo and pulp consisted of a (1→4)-β-D-Xylp backbone substituted with α-L-Araf and 4-O-methyl-α-D-glucuronic acid. The hemicellulose with more side chains tended to be more easily removed from the bamboo cell wall during the CAOSA process. Furthermore, the fractions of hemicellulose exhibited much lower thermal stabilities after the cooking process than the raw material.

Effects of cold liquids on the cured film of selected coatings, the thickness of the final film coating on the resulting surface resistance, and different wood species on the resistance of the coating were investigated. It was demonstrated that different liquids affected the degradation of the cured film coating. The most aggressive liquid used was nail polish remover, followed by ethanol 40%, bleach, vinegar, and mouthwash. The least aggressive was dishwashing liquid. There was no evidence of a difference in the quality of the cured film coating applied on softwood and hardwood. The thickness of the coating had no statistically significant effect on the quality of the film. The liquids used for the tests are commonly used in households.

Medicinal and aromatic plants (MAPs) are widely valued for their aromas, tastes, and treatments for various human illnesses. The chemical constituents and toxicity content of three aromatic plant species, Syzygium polyanthum Wight (Walp.), Monocarpia marginalis (Scheff.) J. Sinclair, and Chromolaena odorata (L.) R.M. King & H. Rob, were determined, via gas chromatography (GC) with mass spectrometry (MS), and flame ionization detector (FID). Altogether, 116 compounds were identified in the essential oils and hexane and methanol extracts. Toxicity evaluations were carried out on human peripheral blood mononuclear cells (PBMCs). Three plant samples were found toxic to human PBMCs. The essential oils of M. marginalis and C. odorata, and the hexane extract of C. odorata yielded IC50 and LD50 values of 76 mg/mL and 6,913 mg/kg, 14 mg/mL and 3,684 mg/kg, and 2.45 mg/mL and 1,927 mg/kg, respectively. Based on the LD50 values, M. marginalis and C. odorata can be classified as slightly and moderately hazardous, respectively. A detailed toxicity evaluation via comet assay showed that M. marginalis and C. odorata induced significant DNA damage (p < 0.05). As for S. polyanthum, the species did not give any cytotoxic or genotoxic evidences.

The design of engineered wood products and timber structures involving numerical simulations requires knowledge of the elastic and strength properties of wood. This study characterized the elastic behavior of Uruguayan pine wood (Pinus elliottii and P. taeda). A series of compression tests with the load applied with respect to various grain directions and bending tests were performed on small and clear specimens to determine the elastic constants and establish the relationships between the longitudinal moduli of elasticity obtained by the two testing methods. Moduli of elasticity, shear moduli, and Poisson ratios were determined. The longitudinal stiffness values in compression from the same specimen obtained by the two testing methods were similar. The moduli of elasticity in tension and compression parallel to the grain for the elastic behavior was obtained from experimental bending tests, and the downshift of the neutral axis until rupture was found. Using a model that simulates the post-elastic behavior as a curve comprised of several straight lines, the stress-strain diagram for tension and compression parallel to the grain was obtained.

In the European Union, timber is used in structural applications and must be graded with a Conformité Européene (CE) mark. To achieve standard, machine strength grading is used. A common technology for these machines is based on using the vibrational response of each wood board to estimate the timber modulus of elasticity and modulus of rupture. The first Eigen frequency is usually used to predict these mechanical properties. However, in heterogeneous wood species such as oak, this parameter is less correlated with mechanical properties. The current study proposes two new methods based on an extended exploitation of the vibrational response that predicts oak wood mechanical properties. The first method was based on the mechanical parameters deduced from several Eigen frequencies that were chosen with regards to a stepwise regression. The second method was based on the full vibrational spectrum and used a partial least squares method. The first method slightly improved the prediction of the modulus of elasticity compared with the first Eigen frequency in edgewise transversal vibration. Both methods significantly improved the prediction of the modulus of rupture.

Hydrochar was used to produce activated carbon with high BET surface area and large pore volume via phosphoric acid activation. The hydrochar described here can be obtained from hydrothermal carbonization of corn cob residue (CCR). Porous structure of activated carbons was characterized by nitrogen adsorption and scanning electron microscopy (SEM). Results showed that the specific surface area and total pore volume of activated carbon were increased to 2192 m2/g and 1.269 cm3/g, respectively, under conditions of 400 °C, 1 h, and an impregnation ratio of 3, from 5.69 m2/g and 0.136 cm3/g of the starting material. The chemical properties of hydrochar and activated carbons were further characterized by Fourier transform infrared spectroscopy (FT-IR), which confirmed the chemical transformation. Furthermore, the localized graphitic nature of the porous carbon was shown by the X-ray diffraction pattern. Thus, the adsorption capacity was enhanced for activated carbon in comparison with commercial carbon. The process of activated carbon preparation provided a high value-added application of hydrochar.

Eco-friendly products have played an important role across all aspects of human life. A wide range of eco-friendly furniture is in use. One of the purposes of this study is to investigate the general perspectives of parents from different demographic origins in terms of eco-friendly design and their tendency towards eco-friendly furniture. Another purpose is to examine the source of consciousness that has led to purchase and use of eco-friendly furniture in terms of parental influence. The data collected in this study were obtained through a questionnaire conducted at an independent furniture store in Kayseri. The hypotheses employed during the research were subjected to ANOVA testing and evaluated graphically with descriptive statistical methods. As a result of the questionnaire, it was detected that parents have an awareness of ecology. They are inclined to prefer furniture that is not harmful for health and environment. Especially, parents with a higher level of income tend to have a higher level of inclination. According to the analyses, despite the existence of eco-friendly furniture in the market, they are not widely preferred by parents due to high prices.

The pulp and paper mill process requires large amounts of water. Therefore, the need to reuse water through the application of coagulation-flocculation processes, which is effective in the removal of solids and colloidal particles, has risen. In such processes, zeta potential (ZP) provides important information about the efficiency of the reagents used. The purpose of this study was to develop individual and combined tests of reagents to study turbidity and COD reduction based on ZP in the process of wastewater internal treatment for recirculation in the pulp and paper process. Factorial models were developed to explain the behavior of ZP depending on the different coagulants/flocculants. The statistical analyses showed that ZP had a positive correlation with parameters related to removal (COD and turbidity). It was demonstrated that innovate use of lentil extract (Lens esculenta) applied with aluminum sulfate favored the treatment, consistent with a coagulation-flocculation mechanism. The optimum doses of lentil extract were able to reduce the requirements of aluminum sulfate by almost 29%, providing an alternative strategy for water reuse processes in the pulp and paper industry.

A novel dual pneumatic feeder was developed to achieve constant and steady biomass conveying for pyrolysis. To facilitate the feedstock replenishment, an injection pipe was installed inside a pressure chamber to convey the feedstock. Another stream of gas entered the pressure chamber from the bottom to fluidize the particles. Experiments were performed to test the performance of the new feeder, and three injection pipes and gas distributors were used. Results showed that the feeding rate depended on both the injection and fluidizing gas velocities. The feeding rate decreased with the inner diameter (ID) of an injection pipe, due to its impact on gas velocity, while the effective injection distance had a negative effect within a certain range. The opening ratio of the gas distributors had a positive effect on the feeding rate. Then, a model was developed, based on the Ergun equation, to describe relationships between the feeding rate and the gas velocities. The classical equation was further reformed to establish the correlation between the solid mass flowrate and the construction parameters of the feeder. The developed model deviated from the measured values within ± 15%, which was considered capable to predict the feeder performances.

The dielectric properties of poplar wood (Populus deltoids cv. I-69/55) were measured using an Agilent network analyzer over the frequency range from 0.2 GHz to 20 GHz. The effects of moisture content, grain direction, temperature, and frequency on the dielectric constant and dielectric loss factor of wood were investigated. Regression equations were also established to predict the dielectric properties of wood having different grain directions and moisture contents. Results showed that the dielectric properties were strongly affected by the moisture content. As the moisture content increased from 0% to 100%, the dielectric constants of wood at longitudinal, radial, and tangential directions increased by 820.2%, 403.0%, and 434.0%, loss factors of wood at three directions increased by 8631%, 4949%, and 3404%, respectively. As frequency was increased, dielectric constant of wood decreased slowly; however, the loss factor decreased at the beginning and then increased. Dielectric properties of the wood also increased with increasing temperature. The dielectric constant in longitudinal directions was 1.2 times higher than the constant at tangential and radial directions, but the loss factor was 1.4 to 2.5 times higher. Regression equations were determined to fully describe the dielectric properties of wood at different grain dimensions and moisture contents.