Volume 13 Issue 3

The management of variables with uncertainties in stochastic cash flow models related to capital investments in energy crops projects allows, in addition to risk measurement, the adoption of proactive measures that can assure the generation of value to the project. This study analyzes the economic feasibility of sugarcane cultivation for bioethanol production from sugar cane molasses, under technical and economic uncertainty. The analysis characterizes sugarcane productivity, capital investment, production costs, and costs of cutting, loading, and transport, considered as stochastic variables. For this, the uncertainty was propagated through Latin hypercube sampling. Sensitivity analysis was also performed to assess the impact of these variables. The results indicated that the productivity of the crop and the sugarcane price in the conveyor belt are determinant to guarantee the economic value of the investment project. There is a high probability of achieving positive NPV (net present value), in addition, MIRR (modified internal rate of return) is 5% higher than MARR (minimum acceptable rate of return).

To investigate the feasibility of replacing eucalyptus fiber with lignin, ternary composites (Lignin/Eucalyptus fiber/Polyvinyl chloride) were prepared by extrusion molding, and the effect of the lignin content on the wood-plastic composites was studied. The microstructure, functional groups, creep behavior, and thermal behavior of the ternary composites were analyzed. The results showed that the tensile strength, flexural strength, and impact strength decreased with an increasing lignin content, whereas, the water absorption, creep resistance, hardness, and heat resistance of the ternary composites improved.

The association between natural mold resistance and the wood’s chemical components was studied for nine wood species. The mold resistance of the different wood species was tested by artificially accelerated tests and scanning electron microscopy (SEM). The chemical components were analyzed by gas chromatography-mass spectrometry (GC-MS). The results indicated that the sequence of mold resistance of different wood flours was as follows, from greatest to least resistance: spruce, Mongolian pine and camphor, toon and teak, eucalyptus (E. urophylla and E. grandis × E. urophylla), sweetgum, and castor straw fiber. GC-MS analysis indicated that the total contents of the antifungal compounds present in all wood flour extractives were consistent with the sequence of mold resistance of wood flour. This suggested that the natural durability of wood flour against molds was affected by its chemical components.

The effects of the tensile elastic properties of fabrics used as cushion covers, foam thicknesses of cushion cores, seat bases as the support of an upholstered wooden furniture seat foundation, and sitting areas of subjects were studied relative to the load-deformation behavior of cushions situated on wooden seat base frames when subjected to human sitting forces. The experimental results indicated that the sitting area of a subject, fabric tensile elastic constant, and foam thickness had significant effects on the cushion stiffness, but the seat base type did not. The sitting area of a subject had the greatest effect on the cushion stiffness constants, followed by the fabric tensile elastic constant and foam thickness. A regression technique was proposed to derive a power equation for the estimation of the cushion stiffness using the parameters investigated in this study.

Fungi and microbes can remarkably degrade the appearance and durability of organic materials, such as wood. The inhibitory effects of natural phenolics may offer more sustainable alternatives to preserve wood than the toxic biocides that are currently used. Although pure caffeine has been proven to have antibacterial properties, the applicability of spent coffee in wood preservation has not been determined. This work conducted in vitro tests with three brown rot and one white rot fungi and demonstrated the potential of spent coffee-derived cinnamates, analyzed with high-performance liquid chromatography, as antimicrobial agents. Spent coffee at concentrations of 1% and above in the growing media caused significant growth suppression of all of the fungi. This was not only because of the caffeine, but also the other chemicals present in the residue extracts, which demonstrated that spent coffee could be used as a source of green chemicals in wood preservative formulations.

Biomass from agricultural waste can be an excellent source of sustainable energy, the most notable of which is bioethanol. This study aimed to adapt and improve bioethanol production using a yeast strain that ferments the sugar content in undiluted and non-added nutrient vineplant bunch hydrolysates. Yeasts that were previously isolated and molecularly characterized were screened for their pentose fermenting capabilities, first in solid and then liquid mediums. Then, 10 native xylose fermenting yeast strains were tested for their ability to produce ethanol from acid hydrolysates from vineplant lignocellulosic waste. The five strains that exhibited the highest ethanol production underwent fermentation in the pure (non-detoxified) hydrolysate. The strain Pichia kudriavzevii D12 in the undiluted hydrolysate medium gave the highest ethanol concentrations and yields. Hence, P. kudriavzevii was selected for adaptation with sequential fermentations. As a result, a 59% increase in the ethanol production (g/L) was recorded for the D12 strain in the undiluted hydrolysate medium during the adaptation studies. A 2.9-fold increase in the yield (g/g) was obtained for this sample when compared with the reference medium. This study determined that a nondetoxified, organic waste medium prepared from vineplant bunches without added nutrients is a suitable substrate alternative for bioethanol production.

To obtain a lightweight and high-strength wood sandwich structure, a wooden lattice sandwich cell element was designed in combination with a pyramid-type structure. After inserting glue to prepare the cell unit, the influence of panel thickness and core diameter on the unit cell force was analyzed and compared under the condition of flat pressure. Under the condition of flat pressure, the specific strength of the unit cell was higher than that of the specific strength of the composition material, and the unit cell may be regarded as a structure with high specific strength. Theoretical predictions, simulation analysis, and experimental tests demonstrated that the structure compressive capacity depended on the diameter of the core when the core length was set. The larger the diameter of the core is, the stronger the bearing capacity of the unit cell will be. When the diameter of the core is constant, the longer the core length is, the weaker the bearing capacity of the unit cell will be. The simulation analysis was in agreement with the experimental test results, indicating that the destruction of the structure was mainly caused by the failure of the core.

Long fibers from fast growing hemp (Cannabis sativa L.) were used as a raw material for the production of insulation boards in this preliminary work. Hemp fiber boards with densities that ranged from 300 kg/m³ to 1100 kg/m³ were studied. The boards were pressed as one- or three-layered structures. In the three-layered structure, the core was formed of hemp fibers and the outer layers were manufactured from 1.5-mm thick birch veneers. The basic insulation properties of the boards were tested. The heat transfer coefficient value for the boards without veneers allowed this material to be classified as an insulating material. Although the additional veneer layers significantly impaired the heat transfer coefficient, its value was still lower than that of standard wood-based board materials with a similar density. The produced boards were characterized as having good noise reduction properties. The acoustic insulation factor was higher compared with boards intended to be used as thermal insulation, such as mineral wool or light fiberboards with four times greater thicknesses.

An ecofriendly approach for the synthesis of plastic biomaterials based on renewable materials suitable for 3D printing application or other applications has been developed. The material was prepared from native (microcrystalline) or amorphous cellulose, citric acid, and glycerol or ethylene glycol, by a pretreatment at 40 °C and a curing at 175 °C for 1 h. The results showed that tensile properties and the water absorption level of the material were acceptable. The highest strain at break (14%) was obtained from materials made of 10% amorphous cellulose with 90% glycerol/citric acid. It had a maximum stress at 37 MPa. Moreover, materials were without ash content. Possible applications of the material in 3D-printers were discussed. In addition, application of mechanical pulp and wood powder into novel plastic material production was discussed. Foaming during curing might be a problem for this type of material, but this can be avoided by using amorphous cellulose in the recipe.

Wheat straw samples at the plant scale (> 1 mm), tissue scale (100 to 500 μm), and cellular scale (30 to 50 μm) were produced to characterize their microstructure and adsorption properties. The effects of changes in the microstructure and adsorption properties on the adsorption capacity of Pb2+ were investigated. The results implied that specific surface areas and pore volumes in the cellular-scale sample were four to five times larger than at other scales, as superfine grinding destroyed the structure of tissues and cell walls. The crystallinity declined significantly from 53% to 34% with decreasing fragmentation scale. Changes in adsorption properties (point of zero charge, acidic functional groups, and cation exchange capacity) were not apparent. The pseudo-second-order model and Langmuir isotherm model fit the experimental data better than alternate models. The adsorption capacity of Pb2+ increased significantly with decreasing fragmentation scale. The main mechanism improving the adsorption capacity of Pb2+ was intensive complexation owing to an increase in cellulose accessibility to water and enhanced chemical reaction activity of the hydroxyl groups, rather than physical and electrostatic adsorption.