Volume 16 Issue 3

The effects of nanoclay were studied relative to the physical, mechanical, optical, and morphological properties of chemimechanical pulping papers. Nanoclay was incorporated at 0%, 2%, 4%, 6%, 8%, or 10%. To increase the retention, 1% cationic starch was used in all test papers. Handsheets (60 g/m2 in weight) were tested to determine their physical, mechanical, optical, and morphological properties. Up to 2% nanoclay increased the tensile strength; at values greater than 2%, the tensile strength decreased. The addition of up to 4% nanoclay increased roughness; between 4% and 10% nanoclay, roughness decreased. With 10% nanoclay, the tear strength, burst strength, and brightness decreased, but the air resistance, opacity, and yellowness increased. Scanning electron microscopy showed that the nanoclay filled the pore spaces between fibers, thus increasing air resistance. X-ray diffraction patterns indicated an intercalated structure.

Clarinets are made with a variety of materials, e.g., plastic, graphite, porcelain, or even metal. However, the most commonly used material to make clarinets is wood. Today, African granadilla or African blackwood (Dalbergia melanoxylon) is the most popular and most widely used species by leading international companies in terms of clarinet production, because of its high density, color, fine texture, and exceptional durability. This species is also used to manufacture flutes, oboes, and bagpipes, making African blackwood one of the most valuable tree species in the world. However, the focus on the usage of a single species puts considerable pressure on a rare and endangered wood species. Therefore, this work aims to identify viable alternatives to African blackwood in terms of manufacturing clarinets as well as providing a similar combination of instrument characteristics that musicians and companies believe contribute to the value of the instrument, e.g., acoustics, aesthetics, and price.

This work aimed to comprehensively examine the pretreatment efficiency of oil palm empty fruit bunches (EFB) using two different types of deep eutectic solvent (DES) mixtures, i.e., choline chloride/imidazole (DES-I) and choline chloride/glycerol (DES-G) in terms of pretreated EFB structural composition and enzymatic hydrolysis. The influence of the pretreatment temperature (55 °C, 90 °C, 125 °C, 160 °C, and 195 °C), EFB to solvent ratio (1:5, 1:10, 1:15, and 1:20), and pretreatment time (2 h, 4 h, and 6 h) on the performance of pretreated EFB and the generated black liquor was examined. The optimal conditions for EFB pretreatment were 160 °C, 1:5 ratio, and 2 h using DES-I solvent, and 160 °C, 1:10 ratio and 4 h using DES-G solvent. The structural carbohydrates of empty fruit bunch pretreated with DES-I, DES-I EFB1 and DES-G, DES-G EFB2 increased to 66.1%, and 64.6%, respectively. The enzymatic hydrolysis of DES-I EFB1 resulted in higher glucan conversion (92.4%) compared to DES-G EFB2, indicating that DES-I solvent was more efficient than DES-G for EFB pretreatment. X-ray diffraction, Fourier transform infrared spectroscopy, and variable-pressure scanning electron microscopy confirmed the removal of lignin and hemicelluloses from EFB during pretreatment and enzymatic hydrolysis.

Effects of cellulase addition were assessed relative to the co-ensiling performance of air-dried corn stover (DCS) and cabbage waste (CW). The DCS and CW mixtures were co-ensiled with 0 to 0.3% of cellulase addition, and changes in composition, intermediates, and biological activity were characterized. The results showed that the addition of cellulase enhanced the decomposition of cellulose and hemicellulose by 2.51 to 6.93% and 3.41%, based on different dosages and compared with the control. Thus, the content of water-soluble carbohydrates increased. The acid content also increased from 5.8% for the control to the range 5.16 to 8.51% for the samples containing cellulase. Moreover, there was a shift from homolactic to heterolactic fermentation with prolonged ensiling time, coupled with the dominant lactic acid bacteria shifting from Paralactobacillus and Lactobacillus to more of Lactobacillus. Thus, the addition of cellulase improved the relative abundance of Lactobacillus. An assessment of fermentation quality, therefore, suggested that cellulase addition can improve the silage quality of DCS/CW during co-ensiling.

The removal performance and mechanism of Cr(VI) from aqueous solution was studied for a novel micro-nano particle kraft lignin biochar (BC) pyrolyzed at 400 to 700 °C. The physicochemical properties of BC were determined by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and N2 adsorption-desorption isotherms. The results illustrated that the BC had irregular micro- and nanoparticles with abundant pore structure and high BET surface area (111.1 m2/g). The FT-IR results showed that the lower pyrolysis temperature resulted in more oxygen-containing functional groups. The Cr(VI) adsorption capacity decreased with the pyrolysis temperature increasing from 400 to 700 °C, and the maximum percentage removal of Cr(VI) for BC obtained at 400 °C was 100% at pH 2, which suggested that the removal efficiency was mainly dependent on functional groups. Kinetic analysis demonstrated that Cr(VI) adsorption on BC fit well to the pseudo-second-order kinetic model. The adsorption data was well fitted with the Langmuir isotherm models, and the maximum adsorption capacity was 37.2 mg/g at 298K. The BC could be reused twice with Cr(VI) removal of 63.91% and was suitable for Cr(VI) contaminated waste-water treatment.

Compost tea has a lot of potential for sustainable agriculture. The suppressive effect of compost tea on damping-off disease in beans (Phaseolus vulgaris), caused by Rhizoctonia solani, was investigated. The physicochemical properties of the tested compost tea showed the presence of dissolved solids (7070 mgL-1), organic matter (1280 mgL-1), nitrate (3840 mgL-1), and ammonium (90.0 mgL-1). The concentrations of phosphorus, potassium, calcium, and magnesium in compost tea were 22.7, 1540, 214, and 2.40 mgL-1, respectively. The highest inhibition of R. solani growth at a concentration of 30% compost tea filtrate was 87.0% and it was completely inhibited at a concentration of 50%. The application of compost tea or chemical fungicide (Rizolex-T) significantly decreased the pre- and post-emergence of damping-off and enhanced the plants survival. In spite of the total phenol content in bean plants infected with R. solani (15.6 µg·g-1 fresh weight), the treatment of infected plants using compost tea and the Rizolex-T caused further elevation in the phenol content, to 17.5 and 14.7 µg·g-1 fresh weight, respectively. These findings support the use of compost tea as a potential alternative to synthetic fungicides to help achieve environmental sustainability and food safety in farming.

There is a pressing need to develop engineering standards for timber- and other wood-based mats suitable for supporting construction vehicles, etc. In 2018, a group of mat producers and users began discussing a potential grading standard specific to mats. There are large gaps in the literature regarding the performance of the available raw materials as well as bolt-laminated mat systems. This study addresses the issue of determining the strength and stiffness values of a commercially sourced industrial bamboo mat. A total of seven 8 ft × 14 ft (2.44 m × 4.27 m) commercial bamboo mats were cut into 28 billets that were 21.5 in (54.6 cm) in width. The bamboo mat billets were evaluated for bending stiffness (modulus of elasticity [MOE]) and strength (modulus of rupture [MOR]) using a three-point static bending test. The 5th percentile non-parametric tolerance limit (5% NTL) and design value for fiber stress in bending (Fb) were calculated. The mechanical property values measured for the 3-ply bamboo mat were at least 25% less than values reported for mixed hardwood timber mats. This type of structural performance information is helpful and useful in the development of matting standards, as it describes the minimum performance characteristics for this type of composite matting.

Pests have a negative impact on the economy and the environment. There is an increased urgency for adequate pest control because many pests show high adaptation and climate change has created favorable circumstances for pests. For pest control, synthetic chemicals are used that are lethal to non-target organisms and are toxic to pollinators and aquatic invertebrates. Chemical compounds in plants and derivatives from lignocellulosic materials act against pests. The wastewater from lignocellulosic biomass is a potential source of new compounds with bactericidal, fungicidal, and pesticidal effects that have demonstrated inhibitory activity against plant pathogens. Fungicidal, nematicidal, insecticidal, larvicidal, and bactericidal activities have been proven. Inorganic and organic compounds, such as phenols, aldehydes, esters, and furanics, are the main ones identified. Due to the antimicrobial activity of wastewater, applying it to the soil can modify the composition and structure of key microbial communities. Deep research about richness, biodiversity, functionality, and microbials is needed. This review provides a comprehensive overview of wastewater types that have been applied and possible sources to obtain potential compounds for pest control. Moreover, associated active compounds, recovery techniques, and environmental impacts are reviewed.

Print mottle is a serious and common uneven printing defect that occurs when printing coated paper by the offset multicolor printing process. It is characterized by a non-uniform appearance in terms of brightness, gloss, or color density that appears mostly in solid printed areas. Back-trap print mottle and water-interference print mottle occur when the quality of the paper substrate, especially the coating layer quality, is not satisfactory. To cope with this quality problem of coated papers, the understanding of the offset printing process, the requirements of coated-paper quality, and the reasons for this problem should be addressed. In this review, the basic process of offset printing and the mechanisms of print mottles were explored, the importance of coating uniformity in both the coating structure and process was reviewed, and the approaches to cope with print mottle were introduced.

Most industrially used synthetic wood adhesives release formaldehyde, which is carcinogenic for humans. Adhesiveless bonding of wood can be achieved using heat treatment by either hot-pressing method, suitable mainly for wood particles and fibres or by wood welding. Welding of wood, which relies on the heat generated via friction, can be used for bonding two or more solid wood pieces together. The process can be carried out either by linear or rotational wood welding. This review first considers the manufacturing of binderless wood-based panels by hot-pressing. Then this is followed by an in-depth outlook of wood welding and its application in the wood industry. The effects of varying wood welding parameters, such as applied pressure, vibrational frequency and amplitude, holding pressure, holding time, welding time in linear wood welding, and relative diameter difference between the substrate and the dowel in rotational wood welding to obtain joints with optimal mechanical and physical properties is reviewed and discussed. Wood products made by heat treatment (hot-pressing and wood welding) are environmentally friendly, and the brief curing times needed for their manufacture represent a great advantage compared with the usage of wood adhesives to bind pieces of wood.