Volume 14 Issue 1

Removal of colloidal particle and lignin from pre-hydrolysis liquor (PHL) is important for the subsequent processing and utilization of the saccharides in the PHL. Cationic polymers treatment is a common method for the purpose, and pectinase pre-treatment of PHL can improve the efficiency of the treatment with cationic polymers. To investigate the mechanism of pectinase pre-treatment for improvement of the cationic polymer efficiency, polygalacturonic acid (PGA) was added in the colloidal lignin and dissolved lignin model substances systems, respectively, and the effects of polygalacturonic acid (PGA) and its pectinase pre-treatment on the removal of colloidal and dissolved lignin in the following cationic polymer treatment process were studied. The results showed that the presence of PGA caused the increase of negative charge density of the colloidal lignin and dissolved lignin systems, which lowered the efficiency of the cationic polymers and negatively affected the removal of both the colloidal lignin and the dissolved lignin. After pectinase treatment, the PGA present in the colloidal and dissolved lignin system was degraded and the negative effects on the cationic polymers were eliminated, and the efficiency of the cationic polymers was improved. Compared to the colloidal lignin and dissolved lignin systems with PGA, less cationic polymers were needed for the same systems with pectinase treatment to obtain the similar lignin removal level.

Laminated structure design is one of the significant factors that affect the physical and mechanical properties of laminated bamboo sliver lumber (LBSL). Eight patterns of assembly for 5-ply LBSL (LLLLL, LLVLL, LVLVL, LVVVL, LLV’LL, LV’LV’L, LVV’VL, and LV’VV’L) were prepared in this study; L represents one horizontal layer of the bamboo-sliver veneer, V represents the layer that is vertical to L, and V’ represents the layer at an angle of 45 ° to the L (or V). The objective of this study was to investigate the exclusive effect of the laminated structure design on the performance of the LBSL, rather than the multiple effect of the number of plies, chemical components, matter content, etc. The results indicated that the bending modulus of elasticity (MOE), bending modulus of rupture (MOR), impact strength, tensile strength, and compressive strength decreased with the decrease in number of layers of ply, for the following levels of L-ply: 5-L-ply (LLLLL), 4-L-ply (LLVLL, and LLV’LL), 3-L-ply (LVLVL, and LV’LV’L), and 2-L-ply (LVVVL, LVV’VL, and LV’VV’L). For the LBSL with the same number of L layers, those which had more V’ layers possessed better properties, due to the action of the parallel component of the force of the V’ layer. The values of absorption swelling rate, breaking strength, and displacement indicated that the LBSL with higher structural complexity achieved poorer underwater dimensional stability, but better single-bolted connection performance.

The ground layer of Chinese ancient lacquer furniture is located below the lacquer film. It is a crucial layer to reinforce the restoration of the furniture, since the ground layer can increase the reinforced strength. In this experiment, lacquer films with and without ground layers were selected as the key materials that were bonded onto wood blocks with various ground layers via adhesives including lacquer, bone glue, and polyvinyl acetate (PVAC). A scanning electron microscope (SEM) and mechanical test machine were used to observe the ground layers, the permeation of the adhesives, and reinforced strength of lacquer film. The experiment showed that the ground layer can affect the reinforced strength of lacquer film in the permeation and effective bonding of adhesives. Good permeation increases the strength of lacquer film because of the coarse ground layer. The effective bonding of adhesives includes the film-formation of lacquer, the gel prevention of bone glue, and the successful polymerization of PVAC, which also can increase the strength of the lacquer film.

The effects of using blends of unleaded gasoline and refined fusel oil on engine performance and exhaust emissions were analyzed. Prior to the experiment, the fusel oil, which is the final waste product of the sugar factory, was developed to have the chemical properties that can be used in internal combustion engines by removing water and gum contained therein. A four-stroke, single-cylinder, spark-ignition engine was used for the experiments. The tests were conducted at a fixed speed and under different loads. The test fuels were blended with fusel oil contents of 5%, 15%, and 30%. Under each load, the engine’s performance and emissions were measured. Throughout the experiments, it was observed that engine torque and fuel consumption increased as the amount of fusel oil in the blend increased. Nitrogen oxide (NO_x), carbon monoxide (CO), and hydrocarbon (HC) emissions were reduced as the amount of fusel oil in the blends increased.

The wood veneer from Monopetalanthus species was heated under different temperatures (120 °C, 160 °C, 200 °C, and 240 °C) and then laminated as the surface of laminated veneer lumber (LVL). Bending modulus of elasticity (MOE), modulus of rupture (MOR), and impact toughness (IT) of the LVL were tested. The results showed that the failure location became scattered as the surface veneer carbonization temperature was increased and that the failure mode changed from split failure in the control and the 120 °C samples to crack failure in the 160 °C, 200 °C, and 240 °C samples under the bending load. Fiber tearing was visible in all five sample types, where the length of the tearing fibers became shorter with increased surface heating temperature under impact load. The carbonization temperature of surface veneer had a minimal effect on the MOE but a considerable effect on the MOR and IT, and the MOR mainly showed a downtrend. The IT loss decreased as the surface veneer carbonization temperature was increased.

The goal of this study was to develop an operational steam explosion pretreatment for effective modification of rice straw chemical structure in order to improve its biodegradability and methane yield. The parameters of pressure (5 bar to 15 bar), moisture (0% to 70%), and time (1 min to 15 min) were studied in steam explosion pretreatment. The steam explosion efficiency was investigated according to the changes in crystallinity structure and chemical composition on rice straw, as well as the methane yield from straw. Steam explosion changed the structure linkages between the lignin and carbohydrate, which was indicated by a reduction in the peak intensities in the bonds from 1648 cm^-1 to 1516 cm^-1. After pretreatment, the crystallinity index of the rice straw in the 10 bar-10 min cycle with no moisture and 15 bar-10 min cycle with 70% moisture increased from 22.9% to 28.3% and 28.6%, respectively. Steam explosion efficiently decreased the lignin. The highest reduction in the amount of lignin was observed with the 10 bar-10 min cycle, which reached from 18.6% to 13.0%. The methane yield increased with the cycles 10 bar-10 min and 15 bar-15 min with 35% moisture, and 15 bar-10 min with 70% moisture by 113%, 104%, and 147% compared to that of the untreated straw, respectively. Moreover, the highest biodegradation percent of the rice straw was obtained in these cycles.

Biomass fractionation is important for the further conversion of the cellulosic fraction and the effective utilization of the lignin fraction for the production of biofuels and value-added products. Solvent properties play a crucial role on the fractionation efficiency of lignocellulosics using an organosolv fractionation process catalyzed by acidic ionic liquids (AILs). Herein, 12 organic solvents were selected as co-solvents with water based on their solubility parameters for lignin dissolution, including alcohols, alcohol ethers, lactones, and alkanolamines, in order to fractionate poplar and rice straw. Effects of fractionation liquor solubility parameters on the delignification efficiency of organosolv fractionation were investigated under the same conditions. Relative energy differences (REDs) of the co-solvent systems for lignin dissolution were closely related to the degree of delignification with adjusted coefficients of determination of 0.899 and 0.800 for poplar and rice straw processes, respectively. The application of solubility parameter analysis may provide a rational way to screen solvent or co-solvent fractionation systems for biomass fractionation process.

To study the flexural behavior of a composite beam, original single and double bamboo beams (SBBs and DBBs, respectively) and sprayed lightweight composite mortar-original bamboo composite beams (SCBs and DCBs) were designed and subjected to a four-point bending test based on the moisture content of the original bamboo. The failure modes, bearing capacity, and initial flexural rigidity of all of the beams were analyzed. Also, the strengthening effect of the lightweight composite mortar on the flexural behavior was studied. The results showed that a higher moisture content in the bamboo degraded the anti-slip property of the bond interface between the lightweight composite mortar and bamboo. The moisture content of the bamboo should be kept at approximately 20% before spraying. The initial flexural rigidity and bearing capacity of the DBBs were approximately 2.5 times and twice that of the SBBs, respectively. The initial flexural rigidities of the SCBs and DCBs were approximately 3.8 and 5.7 times that of the SBBs and DBBs, respectively. The ultimate load bearing capacity of the composite beams was approximately 1.5 times that of the original bamboo beams. It was shown that the lightweight composite mortar had a remarkable strengthening effect on the flexural behavior of the original bamboo.

Air leaks have a considerable impact on the energy load and durability of buildings, particularly in cold climates. In wood construction using cross-laminated timber (CLT), air leaks are most likely to be concentrated at the joints between panels and other elements. This study used simulations of heat, air, and moisture transfers through a gap between two CLT panels causing air leakage in winter conditions under a cold climate. A real leakage occurrence was sized to validate the simulations. The aim of this work was to assess the impact on the energy loads and the durability of an air leak, as either infiltration or exfiltration, for different gap widths and relative humidity levels. The results showed that infiltrations had a greater impact on the energy load than exfiltrations but did not pose a threat to the durability, as opposed to exfiltrations. Gap sizes in CLT may vary, but the effect on the energy load was sensitive to the leakage path in the rest of the wall. As expected, a combination of winter exfiltration and a high level of interior relative humidity was particularly detrimental.

This study focused on the reuse of wheat straw and waste engine oil by producing pellets with mixtures of the two products. Oxidative thermogravimetric experiments were carried out after blending the wheat straw with different amounts of the waste engine oil additive. Based on the results of these experiments, the effects of additive contents on the pyrolysis properties were obtained. Based on a single pellet unit, experiments were conducted to make pellets from wheat straw blended with the waste engine oil additive under different moisture content, temperature, and pressure conditions. The influences of additive content on the specific energy consumption, pellet density, tensile strength, and higher heating value (HHV) were investigated based on the experimental data. Finally, comparisons were made between the effects of waste engine oil additive and the additives used in other studies. The results showed that the use of waste engine oil additives had few effects on the pellet density but increased the HHV, and decreased the ignition temperature, specific energy consumption, and tensile strength.