Research Articles

Wavelet neural networks (WNNs) were used to investigate the influence of operational variables in the soda-ethanol pulping of oil palm fronds (viz. NaOH concentration (10-30%), ethanol concentration (15-75%), cooking temperature (150-190 ºC), and time (60-180 min)) on the resulting pulp and paper properties (viz. screened yield, kappa number, tensile index, and tear index). Performance assessments demonstrated the predictive capability of WNNs, in that the experimental results of the dependent variables with error less than 6% were reproduced, while satisfactory R-squared values were obtained. It thus corroborated the good fit of the WNNs model for simulating the soda-ethanol pulping process for oil palm fronds.

Microstickies in whitewater have caused serious deterioration of paper quality and low efficiency of paper machine runnability. To solve this problem it is necessary to master the characteristics of various aspects of microstickies. In this study, the physicochemical properties and size distribution of microstickies in whitewater of three typical kinds of waste papers, old newspaper (ONP), old book paper (OBP), and mixed office wastepaper (MOW), were investigated by conventional methods and a modified Flow Cytometry Method (FCM). The results showed that white water microstickies in different kinds of waste paper have different characteristics. This is a premise for analyzing stickies problems. Furthermore, in a certain kind of waste paper, the physicochemical properties and the direct determination of size and number of microstickies particle in whitewater can be combined together and taken as a whole to account for more phenomena or deduce more mechanisms, such as agglomeration and deposition, etc.

The maximum deformation and the stress state of furniture doors with different configurations of hinges were analyzed using finite element analysis with the ultimate purpose of optimizing the hinge configuration. The results showed that the maximum deformation decreased when the end distance ratio (Tp) also decreased. It was concluded that the end distance ratio (Tp) should not be greater than 1/8 when two hinges are mounted. The maximum deformation decreased when the number of mounted hinges was more than two. It is suggested that the number of mounted hinges is three when the dimensions of a furniture door are within normal values, considering the limitations in precision of processing and location. The maximum deformation was least when the middle hinge spacing ratio (Sp) was 1/3 and the mounting hinge number was four. The von Mises stress distribution was uniform within the door, and stress concentration only occurred in the vicinity of the mounted hinges. A material with high modulus of elasticity could contribute to minimizing the maximum deformation.

Two hemicellulose fractions were obtained by extraction of one-month- old young bamboo (Phyllostachys pubescens Mazel). The fractionation procedure employed 2% NaOH as extractant, followed by filtration, acidification, precipitation, and washing with 70% ethanol solution. The total yield was 26.2%, based on the pentosan content in bamboo. The physicochemical properties were determined and sugar composition analysis showed that the hemicelluloses consisted mainly of xylose, arabinose, galactose, and a small amount of uronic acid. Furthermore, based on FT-IR and NMR spectra analyses, the structure of hemicelluloses was determined to be mainly arabinoxylans linked via (1→4)-β-glycosidic bonds with branches of arabinose and 4-O-methyl-D-glucuronic acid. The molecular weights were 6387 Da and 4076 Da, corresponding to the hemicelluloses HA and HB. Finally, the thermal stability was elucidated using the TG-DTG method. The obtained results can provide important information for understanding young bamboo and the hemicelluloses in it.

This paper deals with the product design, engineering, and material selection intended for the manufacturing of an eco-friendly chair. The final product is expected to combine design attributes with technical and legal feasibility with the implementation of new bio-based materials. Considering the industrial design, a range of objectives and trends were determined after setting the market requirements, and the final concept was proposed and modeled. The product geometry, production technology, and legal specifications were the input data for product engineering. The material selection was based on the technical requirements. Polypropylene (PP) composite materials based on coupled-fiberglass, sized-fiberglass, and coupled-stone ground wood reinforcements were prepared and characterized. Final formulations based on these PP composites are proposed and justified.

High-density wood is required in wood flooring, especially in engineered wood flooring (EWF) designed for heavy-duty applications. However, high-density wood resources are limited and their cost is high. A densification treatment makes it possible for low- or moderate-density woods to replace harder species by modifying them into high-performance and high-value products, such as engineered wood flooring for heavy-duty applications. The general objective of this study was to develop a prototype of engineered wood flooring using sugar maple hygro-thermally densified surface layers. The results showed that thin sugar maple lumber densified at 200 °C under the combined effects of steam, heat, and pressure with a heat-resistant fabric had great potential for the manufacturing of engineered wood flooring for heavy-duty use. As a result of treatment, it acquired high density, improved mechanical properties, and it had a relatively high dimensional stability and an attractive color. Tests in conditioning rooms showed that the EWF with a densified sugar maple (Acer saccharum March.) surface layer presented the lowest amplitude distortion between the dry and humid conditions compared with the standard EWF (0.15 mm vs. 0.17 mm and 0.25 mm).

In this study, the impact bending strengths and specific impact bending strengths were determined for solid wood and laminated veneer lumber (LVL) produced from eucalyptus (Eucalyptus grandis W. Hill ex Maiden), poplar (Populus x euramericana I-214), and beech (Fagus orientalis L.) woods using urea formaldehyde (UF), melamine urea formaldehyde (MUF), and phenol formaldehyde (PF) adhesives. The tests were conducted in the flatwise and edgewise directions. In addition, specific impact bending strengths were calculated. Three-way ANOVA test results indicated that the effects of the species of tree and the direction of the load on the impact bending and specific impact bending were statistically significant. The type of adhesive was found to be insignificant. In addition, the results showed that impact bending strengths of solid beech and eucalyptus woods were greater than those of LVLs made of beech and eucalyptus, and no statistical differences were determined between solid poplar wood and LVL made of poplar.

The objective of this study was to determine the processing conditions for obtaining improved pulp properties from the kraft pulping process with an alkali pre-extraction stage. Before the kraft pulping, a pre-extraction of hemicelluloses from mixed hardwood chips was performed with two different alkali concentrations (3% and 12% as Na2O) at 150 °C for 90 minutes. The kraft pulping of the pre-extracted chips was then conducted in two ways: with either the H-factor alone controlled or with both the H-factor and the alkali charge controlled. When the chips were pre-extracted with the 3% alkali charge and with the kraft pulping controlled to an H-factor of 500, the yield and properties of the pulp were higher than those of the reference kraft pulp. The 12% alkali pre-extraction and kraft pulping resulted in a low yield of screened pulp. However, when the alkali charge and the H-factor were adjusted together, the pulp yield remained constant and the pulp properties improved in comparison to the reference pulp for both the 3 and 12% cases.

The extraction parameters of intracellular polysaccharide (IPS) from Hypsizigus marmoreus SK-01 mycelia were optimized, and the antioxidant activities of IPS were investigated. The optimum conditions of IPS extraction were predicted to be: an ultrasonic treatment time of 618.07 s, an extraction temperature of 84.53 °C, a pH of 7.57, and an IPS yield of ca. 6.84%. The in vitro inhibition effects of IPS on hydroxyl, superoxide anion, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals were 52.63 ± 3.19%, 68.21 ± 5.09%, and 63.43 ± 5.27%, respectively, and the EC50 values of IPS were 0.85 ± 0.05 g/L, 0.47 ± 0.03 g/L, and 0.62 ± 0.04 g/L, respectively. The activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) in mice blood were 2.52 ± 0.02 U/mL, 453.19 ± 38.43 U/mL, and 118.59 ± 9.64 U/mL, respectively. The results provide a reference for large-scale extraction of IPS by H. marmoreus SK-01 in industrial fermentation, suggesting that IPS can be used as a potential antioxidant that enhances adaptive immune responses.

Causticizing precipitated calcium carbonate (CPCC) as a by-product of the green liquor causticizing process can be used as paper filler to save resources and reduce costs. In this study, CPCC was prepared with green liquor and quicklime, which were obtained from an alkali recovery line of a paper mill. The factors influencing crystal morphology of CPCC, such as slaking temperature, slaking time, and causticizing time were investigated. The morphology of CPCC was observed and analyzed for optimizing reaction conditions. The following were compared: properties of CPCC obtained in this study, conventional CPCC (white mud) from a paper mill, and commercial PCC as fillers. The results showed that slaking time and causticizing time were important for morphology control. Spindle-like and rod-like CPCC obtained in this study had better drainability and retention, higher paper bulk, opacity, and physical strength compared to conventional CPCC, and had nearly the same performances as commercial PCC.