Volume 12 Issue 3

Cellulose-graft-polycaprolactone/polycaprolactone (cell-g-PCL/PCL) was formed by grafting cotton linter pulp with caprolactone via ring-opening polymerization catalyzed by Ti(O-n-Bu)4. The cell-g-PCL/PCL and polycaprolactone (PCL) were used to prepare porous materials (PMs) using solvent exchange and freeze-drying procedures. The obtained PMs were characterized by their porosity, tensile strength, and thermal stability via thermal gravimetric analysis and scanning electron microscopy. The preparation conditions of the cell-g-PCL/PCL PM were optimized based on the characterization results. Compared with PCL PM, cell-g-PCL/PCL PM showed higher porosity and better thermal stability. The adsorptivity of cell-g-PCL/PCL PM for the organic pollutant chlorobenzene was greatly improved compared with that of PCL PM. The adsorption processes of both PMs fit well with the Lagergren pseudo-first-order and pseudo-second-order kinetic models. The results of isothermal adsorption simulation indicated that cell-g-PCL/PCL PM and PCL PM fit better with the Langmuir model and Freundlich model, respectively.

As biomass has become increasingly important, wood pellets are becoming more widely used, and the storage of wood flour, which is the raw material of wood pellets, has become inevitable. The purpose of this study was to reduce the economic losses from fires during storage of porous combustible materials. To achieve this purpose, the authors analyzed and compared the wood flour loss rate between the use of water and the use of wetting agents to extinguish a deep-seated fire through a scale model experiment. To do this, the authors measured the penetration amount of the water and dilute solutions of wetting agent, the weight change of the wood flour holder, and the emissions on a real time basis when that spray amount was the same. Furthermore, the authors analyzed the calorific value and combustion gas to examine the reusability of the wood flour with the added wetting agent. This study quantitatively demonstrated that the active use of wetting agents in wood flour storage fires dramatically reduced the fire loss rate of raw materials and resulted in early fire extinguishing, which minimizes companies’ economic loss.

A commercial woodcutting circular sawblade was analysed in this work. The lateral stiffness on the periphery was measured, and the natural frequencies were determined by modal analyses. The sawblade was modelled by the finite element method, where the influence of the internal stresses caused by roll-tensioning of the sawblade was considered. The roll-tensioning force was determined based on the measurement of the sawblade rolling profile, where it was established that the sawblade had been rolled with a force of 7800 N. The analysis showed that at the aforementioned force, the lateral stiffness was a maximum; here, the calculated and measured stiffnesses were 81 and 60 N/mm, respectively. The calculated natural frequencies agree well with the measured ones, where in the most important vibrational modes there is only a 7% difference. The maximum rotational speed for the sawblade was determined to be 85% of the critical speed. Because the sawblade was clamped with a ratio of clamping of only 0.25, the maximum rotational speed was amounted to 6630 rpm. Increasing the rolling force would increase the critical speed but greatly reduce the lateral stiffness.

The potential of nine fungal strains for pre-treating Eucommia ulmoides Oliver seed shells (EUOSSs) was investigated. Phanerochaete chrysosporium Burds. was found to be the best fungal strain for pre-treating EUOSSs. After co-pre-treatment with acetic acid and P. chrysosporium Burds., which was cultivated in a solid state with an approximately 74% moisture content at 28 °C for 28 d, the weight loss of the EUOSSs was 51.9%. Because of the cooperative efficiency of the biochemical pre-treatment, an enzymatic digestibility value of 86.6% was achieved. The high digestibility value was attributed to the synergism between the acetic acid and fungal treatments, which led to improved enzymatic accessibility of the EUOSSs. As an environmentally friendly processing method, fungal pre-treatment can save a great amount of energy and, in combination with an acetic acid treatment, is more efficient at improving the rate of sugar transformation.

Simulated syngas produced from biomass gasification was evaluated in a compression ignition (CI) engine under a dual fueling mode. Syngas is an economical solution with a carbon-neutral system that could replace petroleum diesel fuel. Syngas can be introduced into CI engines through a dual fueling process. However, syngas dual fueling combustion is very complicated because it consists of several combustion phases. In addition, CI engines operating under the syngas dual fueling mode suffer from low performance. Therefore, this study examined the performance of syngas dual fueling in a CI engine with blended biodiesel as pilot fuel. Two types of simulated syngas, namely typical syngas and high hydrogen syngas, were considered. The simulated high hydrogen syngas was assumed to be the product of biomass gasification with introduction of a carbon dioxide adsorption. The effect of carbon dioxide removal from syngas on the performance of syngas dual fueling in a CI engine at constant engine speed, half load, and different pilot fuel substitution rates was investigated. The combustion characteristics showed a maximum pilot fuel substitution of up to 47% with simulated syngas. Better engine performance was achieved with the simulated typical syngas in terms of brake specific energy consumption and brake thermal efficiency.

A method for the immunological visualization of plant polysaccharides in native plant tissues was adopted for the histological investigation of xylan on kraft pulp and xylan-enriched viscose fibers. The method consisted of the selective labeling of xylan structures through the binding of specific monoclonal primary antibodies and fluorescein isothiocyanate (FITC)-carrying secondary antibodies. This indirect immunolabeling method was adapted for pulp and viscose fibers through the blockage of unspecific binding sites with bovine serum albumin (BSA), which allowed a selective localization of xylan. The combination of this technique with high resolution confocal laser scanning microscopy (CLSM) rendered a parallel detection of morphological changes of pulp fibers alongside various processing steps possible. Within this study, kraft pulps from birch, beech, and eucalyptus were investigated throughout a purification process that enabled an upgrade from paper pulps to dissolving pulps by caustic hemicellulose extraction and xylan-enriched viscose fibers. The method demonstrated its potential for gaining novel insights into pulp purification, as well as fiber modification through the application of an immunolabeling method.

The hyper-production potential of a cellulase complex from a local strain of Aspergillus tubingensis S2, indigenously isolated from rotten tomato, was investigated. A total of nine fungal species of Aspergillus and Trichoderma were isolated and confirmed through triple-phase screening via 18S ribosomal DNA sequencing and construction of a phylogenetic tree. Congo red testing and the zone of clearance method were used to confirm the cellulase production from A. tubingenesis S2 isolate. A. tubingenesis S2 revealed maximum cellulase production (78 µg/mL/min) and was selected for further study. The optimum fermentative conditions, including the incubation period, pH, and temperature values, were determined to be 96 h, pH 4.8, and 40 °C, respectively, for obtaining the cellulase activity of 86.4±2.1 µg/mL/min. The cellulase was 5.14-fold purified by ammonium sulfate fractionation and gel permeation chromatography. Characterization revealed that maximum activity (130.5 µg/mL/min and 133.5 µg/mL/min) was achieved at 4.5 pH and 40 °C, respectively. A monomeric protein with an apparent molecular weight of 76 kDa was evident after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cellulase revealed maximal activity with 40-mesh size corn stover as compared with 20-mesh size corn stover and 80-mesh size corn stover after 36 h of incubation at 40 °C.

Lemongrass fiber was analyzed to determine the chemical proportion of its lignocellulosic components. Fibers’ thermal behavior, surface structures, and functionality were assessed by thermogravimetric analysis (TGA), scanning electron microscope (SEM), and Fourier transform-infrared spectroscopy (FT-IR), respectively. High-density polyethylene (HDPE) matrix composites filled with varying (10%, 20%, 30%, 40%, and 50%) fiber content were prepared and investigated. Composite wicker was made from HDPE and low density polyethylene (LDPE) blend-matrix and 10% alkaline modified fiber. Alkaline or maleic anhydride grafted polypropylene (MA-g-PP) was used to improve the compatibility between the fiber and matrices. The composites were evaluated by using TGA, SEM microscopy, and universal testing machine, respectively. The fiber was constituted by equitable amounts of lignocellulosic components with cellulose accounting for the highest proportion. It also exhibited high degradation temperature, which was further increased following alkaline modification. Superior thermal degradation behavior was measured for modified fiber composites. SEM showed that the modified fiber composites demonstrated better compatibility. Lemongrass fiber reinforcement substantially improved the mechanical properties of the composites.

Microfibrillated cellulose (MFC) and nanofibrillated cellulose (NFC) isolated from cotton linters were evaluated as a strength additive in unbleached kraft paper and compared with semi-empirical and mechanistic models. The z-directional tensile strength was enhanced due to NFC and MFC. The tensile energy absorption (TEA) derived via integrating the z-directional stress-strain curve was 29.165 J/m2, 120.658 J/m2, and 187.768 J/m2 for the control, MFC, and NFC, respectively. Burst factor significantly increased from 11 to 14 for 10% MFC, while no increase was observed in NFC. From TEA predictions by semi-empirical models, a modified Page equation, Shear-lag, and a negative trend was found due to increased relative bonded area (RBA) with the addition of MFC/NFC. The mechanistic model used six mechanisms involved in binding the fibers and predicted the increased trend of TEA. The increased TEA due to NFC contributed to z-directional tensile strength, but not to the tensile indices and tear factor. This was ascribed to the large size difference of NFC with base pulp fibers and a higher RBA.