Volume 13 Issue 3

A new method of testing mechanical properties of mortise-and-tenon joints is put forward. The contact force relaxation behavior of joints for 3 h with tenons in different grain orientations and tenon fits were studied. The results showed that the initial and final contact force of joints with tenons in radial grain orientation were all larger than those in tangential grain orientation in the same tenon fit. The regression equations generated in this paper were able to predict the contact force relaxation behavior of joints with tenons in different grain orientations, tenon fits, and time, and the errors were all within 20%. In addition, the ratio of loss for contact force of joints with tenons in radial grain orientations was greater than that with tenons in tangent in the same tenon fit. The ratios of loss decreased from 51% to 31% in two grain orientations of tenon with tenon fits increasing from 0.2 mm to 0.5 mm with an increment of 0.1 mm. The method proposed in this paper was able to predict the contact force relaxation of mortise-and-tenon joints. The relaxation of contact force in a joint should be considered when designing mortise-and-tenon joint furniture.

Cellulosic butanol is a very promising renewable fuel to consider for the future transportation market. However, the seasonal availability of the raw materials, high maintenance cost, and high logistical cost of the biomass energy supply chain are the main factors impeding the commercialization and large-scale-production of this energy source. Furthermore, research focusing on an environmental or green supply chain network design of cellulosic butanol has been insufficient. This study focused on designing a green supply chain network for cellulosic butanol. A life cycle analysis was integrated into a multi-objective linear programming model to optimize the cellulosic butanol supply chain network. With the objectives of maximizing the economic profits and minimizing the greenhouse gas emissions, the proposed model can optimize the location and size of a bio-butanol production plant. The mathematical model was applied to a case study in the state of Missouri, and solved the tradeoff between the feedstock and market availabilities of sorghum stem bio-butanol.

The dimensional stability and resistance to degradation of wood can be improved using high temperature heat treatment under anaerobic conditions; however, mildew growth can have a deleterious impact on its appearance and commercial value. In this study, wood samples were impregnated in copper-containing solutions at high pressure before being recovered and cured at high temperatures to create treated wood samples with nano copper particles. This copper impregnated wood (up to 6.35% copper content) suppressed the growth of Botryodiplodia theobromae Pat. and Aspergillus niger van Tieghem with 100% efficiency, and Penicillium citrinum Thom with 75% efficiency. However, the growth of Trichoderma viride Pers. was not suppressed. These results demonstrate that copper curing can be used to extend the scope, performance, and lifetime of heat-treated wood, enabling it to be used for a new range of applications.

Biochar is a carbon-rich product generated from the incomplete combustion of biomass through pyrolysis. Biochar plays an important role in removing pollutants from the environment. In this study, biochars were obtained from peanut shell agricultural waste by the limited-oxygen method at 300, 500, and 700 °C. The adsorption capacity of imidacloprid onto the biochar was increased with the increasing pyrolysis temperature. The solution temperature and biochar dosage had positive effects on the adsorption of imidacloprid. The adsorption capacity of the biochar on imidacloprid was increased with the increasing of pH in acid and neutral solution but slightly decreased in weak base solution (pH 9). An analysis of adsorption kinetics showed that the adsorption of imidacloprid on the biochar perfectly followed pseudo-first-order and pseudo-second-order models with R2 coefficients above 0.97. Furthermore, the Langmuir and Freundlich models highly correlated with the sorption isotherm data. In summary, this study confirmed that peanut shell biochar is an efficient adsorbent for the removal of the pesticide imidacloprid.

Kinetics of the oxidation of D-xylose, a hemicellulose model compound, by chlorine dioxide was studied under simulated bleaching conditions. The final reaction product, chloroacetic acid, which is a type of adsorbable organic halogen (AOX), was detected by gas chromatography-mass spectrometer (GC-MS). The kinetic equation was expressed as dW/dt = 2.36e-560/T[H+]0.05[ClO2]0.11X0.92. The reaction exhibited first-order kinetics, with a good agreement between the experimental and modelling data. The reaction activation energy was 4.66 kJ.mol-1. Thus, the process is not controlled by a chemical reaction, but rather, it is controlled by hemicellulose properties. These results might have potential for resolving the major problems of environmental pollution in elemental chlorine-free (ECF) bleaching of pulp.

Increasing global paper consumption has fostered the search for new alternative non-wood fiber sources. The aquatic weeds Cyperus digitatus, Cyperus iria, and Scirpus grossus were analysed for their fiber characteristics and chemical composition, and the processed fibers were transformed into handmade paper. The selected species yielded medium-length fibers (0.92 mm to 1.03 mm), which were thin-walled with a lumen diameter (3.37 µm to 5.26 µm) wider than cell wall thickness (2.73 µm to 2.97 µm). In terms of fiber derived values, the selected species possessed a slenderness ratio of 86.5 to 113.1 (favourable, > 30) and flexibility coefficient of 35.2 to 47.6 (favourable, within the range 50 to 70), which was classified as rigid fiber. The species also contained high cellulose, 42.1% to 44.8% (favourable, > 40%) and hemicellulose content, 42.8% to 45.6% (favourable, within the range of 30% to 50%), and low lignin content, 10.6% to 11.8% (favourable, < 12%). Handmade paper of Cyperus digitatus possessed relatively high tensile strength (2.61 ± 0.15 kN/m) and breaking length (1.20 ± 0.07 km) among studied species. Comparison with other non-wood fibers indicated that the studied plants fibers can be used for production of paper plates, paperboard, and decorative paper.

A functional ionic liquid 1-butyl-3-vinylimidazolium iodide ([BuVyIm]I) was synthesized, and it exhibited the features of both decay resistance and leaching resistance after in-situ polymerization within wood. Treated wood specimens of Cryptomeria japonica were evaluated in this preliminary study using leaching tests with distilled water and decay tests for 12 weeks with brown rot fungi Fomitopsis palustris. The [BuVyIm]I polymerized by 100 kGy 60Co gamma irradiation was retained in wood after 10 wash and dry cycles, whereas nearly all of the [BuVyIm]I was washed out in the cases of 10 kGy and no irradiation. The decay testing of these specimens showed that sapwood had a different decay resistance depending on the strength of gamma irradiation used, whereas the treated heartwood did not support fungal growth. The results of this study imply that [BuVyIm]I polymerized by 100 kGy gamma irradiation have potential for wood preservation.

Polyvinyl alcohol/palm kernel shell powder biocomposites were prepared by using a solution casting method. To enhance the properties, the crosslinking agent glutaraldehyde (GA) was added to the composition. The effect of the crosslinking agent on the biocomposite was studied based on the change in the tensile properties, physical properties, and biodegradability. The optimum GA content was found to be 2 phr because the tensile properties tended to decrease with higher GA contents. The water absorption percentages and water vapour transmissibility decreased until the GA content reached 2 phr and then increased. It was found that the biodegradability of the film decreased when GA was added.

Concerns regarding the disposal, degradability, and recycling of synthetic fibres used in composite materials have highlighted the need for eco-friendly materials. This article focuses on fabrication and characterization of the fibre metal laminate (FML) reinforced with carbon, flax, and sugar palm fibres in order to reduce the environmental impact without compromising the strength requirements. Out of autoclave (OOA) manufacturing processes, including hand lay-up and hot compression molding, were employed to fabricate the FML. Tensile, compressive, inter-laminar shear strength (ILSS), and fatigue properties of the fabricated FML were studied. The results indicate that tensile properties and compressive strength for flax based FML (CFC) was superior and 23% higher than CSC while 5% higher than the hybrid CFSSFC configuration. CFSSFC outperformed CFC and CSC in the inter-laminar shear strength by showing 6.5% and 25% increment in magnitude. In case of fatigue, CFC showed excellent fatigue resistance by withstanding high fatigue loads and lasted up to 10⁴ cycles before failure. Delamination between the metal/composite plies was observed in fractured samples under all the mechanical loads.

The purpose of the study was to link microbial community composition and chemical properties of various biomass and their resulting digestate residues for their potential use in biogas production or soil enrichment. The order of biogas production, graded from high to low was as follows: corn silage, grass silage, fruit waste, and dairy sewage sludge. Different bacterial families were predominant in different biomass. Corn silage deteriorated as a result of long-term air exposition and may serve as an efficient feedstock substrate for anaerobic digestion. A positive role in plant biocontrol microorganisms found in grass straw residues, and reasonable biogas yield obtained from this substrate suggests the use of grass straw for biogas production and its residues to enrich the soil. Due to potential threat of introducing pathogens into the soil within fruit waste or dairy sewage sludge, or soil acidification by fruit waste repeated use in field application, this biomass should be sanitized prior to soil application. Simultaneously, low biogas yields from fruit waste and dairy sewage sludge substrates make it necessary to transform them in anaerobic digestion with more energetic co-substrates. Tested residues may deliver a robust and wide range of methanogens as inoculum for further anaerobic digestion process.