Volume 14 Issue 2

A shortcoming of the laminated bending process is that the product may become distorted after moulding. This study focused on the influence of fibre orientation deviation for individual veneers on the distortion of a moulded shell. The distortion of 90 cross-laminated shells of the same geometrical shape, consisting of seven peeled birch veneers, were studied under relative humidity variation. All the veneers were straight-grained in the longitudinal-tangential plane, but to simulate a deviation in fibre orientation, some of the individual veneers were oriented at an angle of 7° relative to the main orientation of the other veneers in the laminate. A finite element model (FEM) was applied to study the possibility of predicting the results of a practical experiment. The study confirms the well-known fact that deviation in fibre orientation influences shape stability. The results also show how the placement of the abnormal veneer influences the degree of distortion. From this basic knowledge, some improvements in the industrial production were suggested. However, the FE model significantly underestimated the results, according to the empirical experiment, and it did not show full coherence. The survey shows the complexity of modelling the behaviour of laminated veneer products under changing climate conditions and that there is a great need to improve the material and process data to achieve accurate simulations. Examples of such parameters that may lead to distortion are density, annual ring orientation in the cross section of the veneer, the orientation of the loose and tight sides of the veneer, and parameters related to the design of the moulding tool.

There are few reports on the effect of Chinese eaglewood extractions on the relationship between a stroke-induced nerve and the motor dysfunction caused by the nerve dysfunction. In this study, lipids were successfully induced from white eaglewood, and the cause of extraction were analyzed. Controlled clinical experiments were conducted to study the effects of Chinese eaglewood extracts as a drug therapy on the recovery of nerve and motor function of stroke patients. Such effects were further analyzed using the electroencephalograms (EEGs) test, the Fugl-Meyer upper extremity scale, and the Fugl-Meyer lower extremity scale. The results of the study showed that the nerve function recovery of stroke patients through compensatory effects was promoted by using Chinese eaglewood extracts, and the motor function recovery of patients was further improved. Thus, from the results of the Fugl-Meyer upper extremity and lower extremity scales, the motor functions of the stroke patients were gradually recovered during the clinical experiments, which indicated nerve function recovery. The RNA extraction results showed high RNA purity without the presence of proteins and that interfering substances can be obtained by using the mixed inducer agent. This study demonstrated the feasibility for the application of Chinese eaglewood extracts and its therapeutic efficacy.

Thermal modification is a widely used wood protection method. This method has attracted attention because there are no toxic chemicals used in the process. The influence of thermal modification was investigated relative to the ignitability and the mass burning rate of Norway spruce wood (Picea abies). The spruce wood samples were subjected to temperatures of 100 °C, 150 °C, 200 °C, 220 °C, 240 °C, and 260 °C for durations of 1 h, 3 h, and 5 h. The treatment at temperatures higher than 200 °C resulted in a lower mass loss at 600 s and a lower average relative burning rate, but it did not influence ignition time, the flame-died-out time, and maximum relative burning rate. The class of reaction to fire of the spruce wood samples was not changed due to the treatment. Therefore, it can be stated that the thermal treatment at temperatures below 200 °C does not influence the fire safety of an important class of wooden products.

Solid-state chemical pretreatment at room temperature was adopted to evaluate the methane production potential of rice straw. Dried rice straw was homogenized with distilled water at a 1:3 ratio and pretreated for 6 h, 24 h, 72 h, 120 h, and 168 h. The effects of the pretreatment time with three chemicals (H2O2, Ca(OH)2, and NH3·H2O) on the methane yield were investigated. The results showed that the anaerobic digestion performance was improved for solid-state chemical pretreatment of room temperature-treated rice straw. The biogas yields from the treatments with H2O2 for 168 h, Ca(OH)2 for 72 h, and NH3·H2O for 120 h were 386.6 mL/g VS, 413.5 mL/g VS, and 390.5 mL/g VS, which were 35.8%, 45.2%, and 37.2% higher than that from the untreated rice straw, respectively. Therefore, it is feasible to shorten the pretreatment time of rice straw for these three chemical solutions.

Bamboo can be processed into engineering materials with excellent properties by reasonable processing methods. In this study, the performance of mould-pressed bamboo (MBP) veneer products was examined. The physical mechanical properties and connection properties of MPB were tested, and the application performance of the MPB was analyzed. The results show that MPB has a comprehensive property of high internal bonding and good dimensional stability, and its density and mechanical properties are similar to those of wood dimensional stock. The overall bending strength, bending modulus, and compression strength of MPB were 29.0 MPa, 6.83 GPa, and 15.6 MPa, respectively. While the overall carrying capacity was relatively low, the connection performance of BPM was good. Thus, it can be used as a connector or substructure.

Effects of cross-linking were examined for polyvinyl alcohol, starch, and their blends. The blends were prepared using various compositions of pure starch, pure polyvinyl alcohol (PVOH), and a combination of both starch and polyvinyl alcohol. The cross-linker used for this study was epoxy silane. The blends were tested against the canarium wood substrate for tensile strength. Further properties, such as viscosity and wet tack, were also evaluated. Analytical tests such as differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) demonstrated the phenomenon of cross-linking, having shown an increase in glass transition temperature (Tg) and area under the curve of tan delta. The efficient and novel cross-linking of hydroxyl groups present in the starch and PVOH contributed to better adhesion on the wood substrate and also better cohesion between the chains.

Hemicellulose was isolated from poplar powder using alkaline hydrolysis coupled with alcohol precipitation. Response surface methodology was applied to study the effects of sodium hydroxide concentration, reaction time, and temperature on the extraction yield. The optimal conditions for the extraction of the hemicellulose from poplar powder were an alkaline mass fraction of 9.5%, reaction time of 4 h and 12 min, and temperature of 78 °C. The extraction yield reached 52.8% under this optimal condition. Fourier-transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, and sugar component analyses showed that the obtained hemicellulose with excellent water absorption and heat resistance consisted mainly of 4-O-methyl-glucurono-xylan, and the molar ratio of xylose to glucuronic acid on the molecule chains was 3.95.

In order to reduce the power consumption of the round baler and improve the quality of the bale, the compression and relaxation characteristics of alfalfa were investigated with respect to moisture content, feeding speed, and steel roll speed. Experimental trials were performed by using a steel-roll fixed chamber round baler rotary compression test platform. Three moisture contents were prepared, 18%, 21%, and 24%. The feeding speeds were set at 1.11 m·s-1, 1.39 m·s-1, and 1.67 m·s-1, and the steel roll speeds were 106 r·min-1, 126 r·min-1, and 146r·min-1, respectively. The experimental data for these trails were collected and three compression models and a generalized Maxwell model were fitted to the pressure, density, or time data. The maximum compression pressure decreased with the increase of moisture content and increased with the increase of feeding speed, while the steel roll speed had no significant effect on the maximum compression pressure. The stress relaxation time decreased with the increase of moisture content, feeding speed and steel roll speed. The equilibrium stress decreased with the increase of the steel roll speed and moisture content and increased with the increase of the feeding speed. All compression models had a good fit for the experimental data.

The isolated bacterium Lactobacillus plantarum is strongly tolerant of lignocellulose-derived inhibitory compounds and possesses the ability to produce lactic acid in the presence of 8.0 g/L furfural, 6.0 g/L hydroxymethylfurfural, 4.0 g/L vanillin, and 4.0 g/L syringaldehyde. This bacterium was used in an integrated simultaneous saccharification and fermentation (SSF) process for the production of lactic acid using whole rice straw slurry (with a high solids content of 17%) that had been pretreated with dilute sulfuric acid. This method achieved a lactic acid concentration of 65.6 g/L, which corresponded to a cellulose-to-lactic acid conversion yield of 69%. These results demonstrated that isolated bacterium and the proposed integrated SSF process are able to produce high concentrations of lactic acid. Furthermore, this proposed process does not require detoxification and had a conversion efficiency that is comparable to that obtained using the conventional SSF process, which requires the addition of fresh water. Therefore, it was concluded that the proposed process is promising for commercial lactic acid production and could make the production of lactic acid from lignocellulosic biomass more practical in the future.

A cellulose-based oil adsorbent was developed utilizing the waste paper PS-16 (mixed kraft cuttings) via a simple modification process. Through mechanical treatment and spray with polyethylene wax and alkyl ketene dimer, it was found that the product was significantly more hydrophobic than the raw material, with a water contact angle of 125.6°. The capability of the product to absorb engine oil, kerosene, and xylene was studied and compared with other cellulose-based adsorbents. The adsorbent had an excellent performance with a high absorbing ability of 16 to 28 times its own weight. Up to 92.8% of the oil in the adsorbents could be easily recycled and collected by manual squeezing. The adsorbent could be reused over eight cycles, and the sorption capacity remained constant. Therefore, this adsorbent is expected to be a promising oil sorbent for potential applications like oil spill clean-ups.