Research Articles

Effects of microbial decomposer application were studied relative to in situ decomposition of paddy straw in the rice-wheat system using both paddy straw incorporation (i.e. mechanical mixing of leftover straw and stubble using rotavator) and retention (i.e. leftover straw and stubble without mechanical mixing) methods. An experiment was conducted on paddy straw degradation during 2020-2021 and 2021-22 using microbial consortium (decomposer) at four locations in Punjab, India using three different treatments. Lignin content, C/N ratio, and tensile strength after 30 days of incorporation and retention of paddy straw were recorded. Microbial treatment along with incorporation improved decomposition parameters from 32.0 to 32.6% (C/N ratio) and 47.5 to 36.6% (lignin), whereas a major share – 28.6 (C/N ratio) and 36.6 (lignin) per cent of decomposition was achieved by soil incorporation as such. Wheat grain yield with and without microbial decomposer was similar across sowing methods (incorporation vs retention) in all locations. Similar observations were recorded in 2021-22 also at the same site of PAU, Ludhiana. Microbial agents responsible for the degradation of straw are present in sufficient quantity in the soil and incorporation of paddy straw in the soil by incorporation using a rotavator can enhance the paddy straw decomposition.

Commercial kitchen towels (basis weight 39 to 56 g/m²) made of virgin and recycled fiber, produced by Through-Air-Drying (TAD), and conventional Yankee cylinder drying (with creping) were analyzed. The properties of these commercial tissue products were compared to those of handsheets made from them. Laboratory tissue handsheets were also prepared from northern bleached softwood kraft (NBSK), eucalyptus, bamboo, and straw pulp. Fibers were refined with up to 5000 revolutions of a PFI mill. Commercial kitchen towels (kitchen tissue) absorbed 9 to 14 g water per 1 g of fiber, with higher absorption by virgin fibers, and when using TAD. The tensile index (dry) was 3 to 14 Nm/g. Laboratory tissue handsheets made of commercial samples absorbed less water, but the tensile index (dry) was higher in most cases. Higher beating levels (tested at NBSK, eucalyptus, bamboo, straw pulp) increased tensile index. Curl, bulk, softness, absorption capacity, and suction lift were reduced with refining. Best values for absorption capacity (almost 8 g/g), bulk (almost 5 cm³/g), and softness were observed in laboratory bamboo tissue sheets made of non-refined fibers. After refining (2000 revolutions), the tensile index of such tissue sheets made of bamboo increased from 10 to 30 Nm/g.

To make use of rubidium salt resources in the Qinghai Salt Lake and to valorize Stellera chamaejasme L., mesoporous activated carbon was prepared by a chemical activation method using rubidium chloride as an activator. Using methylene blue and iodine as pollutant models, the adsorption capacity of mesoporous activated carbon was determined. The specific surface area, pore structure, and surface functional groups of mesoporous activated carbon were determined using a fully automated specific surface area analyzer, X-ray diffractometer (XRD), Raman spectrometer, scanning electron microscope (SEM), Fourier transform infrared spectrometer (FT- IR), and an X-ray electron spectrometer (XPS). The surface functional groups of mesoporous activated carbon were found to be mainly comprised of carbon and oxygen. The mesoporous activated carbon had a certain graphitized microcrystalline structure. The carbon yield of the mesoporous activated carbon was 13.55% ± 0.41%, the specific surface area was 877.02 m²/g, the adsorption amount of iodine, 891.35 mg/g, and the adsorption amount of methylene blue, 256.95 mg/g. The dominant pore size was 0.945 nm, the average pore size was 2.43 nm, and the pore volume was 0.26 cm³/g.

The potential effects of combining biochar with hyperaccumulator plants on heavy metal stabilization and uptake in Cd and Pb-contaminated soils have received limited attention. This study used biochar (BC) at levels ranging from 0 to 40 t ha^-1 as soil amendments in Cd and Pb contaminated rice paddy soil. Biochar significantly decreased soil bioavailable Cd and Pb concentrations 6.7 to 16.6% and 10.6 to 39.7%, respectively, compared to the control. The shoot and root Cd concentrations in Arabidopsis helleri increased significantly by 33.5% and 133.1%, respectively, in the C3 treatment compared to the control. Similarly, shoot Pb concentrations showed a 57.5% increase compared to the control, but no significant changes were observed in root Pb concentrations. The Arabidopsis helleri bioconcentration factor (BCF) saw an increase of up to 40.5% for Cd and 57.8% for Pb with the C3 treatment. Conversely, the Cd translocation factor (TF) decreased 42.8 to 49.1%, while the Pb TF increased 32.8 to 96.6% with biochar application. The majority of Arabidopsis helleri-biochar Cd and Pb was found in the B3 fraction (organic fraction), constituting over 50%, and even over 80% for Cd. The Arabidopsis helleri-biochar primarily contained organic char binding Cd and exhibited slow-release characteristics.

Wood scrimber as a promising eco-friendly material in wood technology. This study evaluated the physical and mechanical properties of ginkgo scrimber, focusing on density, moisture content, water absorption, thickness swelling, flexural modulus of elasticity, bending strength, tensile modulus of elasticity, tensile strength, compressive modulus of elasticity, compressive strength, and shear strength. The results showed that the material had low variation in density and moisture content, indicating good homogeneity of the material. Mechanical properties tests showed that the material’s mechanical properties met high-quality standards, although variability in bending strength suggested potential issues with adhesive application. Some specimens experienced fractures perpendicular to adhesive layers, affecting strength. Despite this, ginkgo scrimber exhibited mechanical properties comparable to or exceeding those of reconstituted bamboo and laminated veneer lumber. The findings highlight its potential for construction, with recommendations for improved adhesive application and manufacturing processes to enhance performance stability.

The aim of this research was to investigate the effect of false heartwood of beech wood on the shear strength of glued joints for thermoplastic and reactoplastic adhesives for plywood production. The tensile shear strength of the lap joints was tested for four different types of adhesives according to EN 204 (2016) and EN 205 (2016). The results showed that for lap joints assembled with polyvinyl acetate, urea-formaldehyde, and phenol-formaldehyde adhesives, there was no significant difference in shear strength between beech sapwood and false heartwood. However, for joints bonded with polyurethane adhesive, the shear strength was lower for heartwood compared to the reference sapwood, particularly after exposure to water immersion.

Agro-residues, including banana peel, pineapple peel, mango peel, apple peel, and coconut husk, were utilized to produce extracellular polysaccharide (EPS) via solid state fermentation(SSF) by the fungus, Trichoderma hamatum. EPS production was highest in pineapple peel (84.2 ± 0.4 mg/g), followed by mango peel (70.3 ± 0.41 mg/g) (p<0.01). The SSF bioprocess was optimized via a two-level full factorial design and response surface methodology. The effects of five selected variables on EPS biosynthesis, namely, the concentrations of glucose (10 to 30%), ammonium sulphate (0.1 to 1%), yeast extract (0.5 to 2%), MgSO₄ (0.01 to 0.1%), and medium pH (4.5 to 6.5), were analyzed via a full factorial design (FFD). The EPS production ranged widely from 15.3 to 576.2 mg/g substrate. Three significant variables affecting EPS production were assessed in central composite design (CCD) to optimize concentrations of MgSO₄, and glucose, and the pH. The designed CCD model was fitted to the quadratic model and was significant (p<0.0001). For 50 μL of EPS, the scavenging ratio was 43.4 ± 4.1% at a concentration of 200 μL (78.5 ± 6.9 μL) (p<0.01). The extracted EPS exhibited an alpha-glucosidase inhibitory effect (p<0.001). Solid-state fermentation allows the utilization of low-cost biomass for EPS production and the application of T. hamatum EPS as a natural antioxidant and α-glucosidase inhibitor.

This article presents results obtained for the chipless cutting of wood using different cutting heads. Wood processing in forestry and the demand for firewood are currently increasing, so it is necessary to apply appropriate tools to the existing process, which will be sufficient for fast and high-quality operations. Four groups of cutting knives were used for experimental measurements, where the influence of the cutting knife edge on the cutting process was determined. The cutting knives were always made of the same material and with the same blade angle ∢ 30°. Measurements were made on spruce (Picea abies), beech (Fagus sylvatica), and willow (Salix caprea) trees. The size of the F_c cutting force was selected as the monitored variable, and then the dependent factors (kind of wood, wood diameter, cutting knife) were monitored in terms of their influence on the size of this F_c cutting force and thus also on the energy consumption. Based on the statistical evaluation, the most suitable shape of the cutting edge of the knife was selected, with this shape of the cutting edge, a reduction in the cutting force F_c was achieved for selected woods.

Rattan is an important non-wood forest product, which shows a natural gradient in its structure from cane cortex to core. Toughness is its main characteristic, which is closely related to resistance to fracture. In this study, based on the principle of linear elastic fracture mechanics, the fracture toughness of Plectocomia kerrana Becc., was studied in two directions whose cracks were prefabricated from the cane cortex and from the cane core, respectively. The results showed that the average fracture toughness of pre-cracked from the rattan cane core was 0.476 MPa·m^1/2 measured by the SENB method. This value is much smaller than bamboo, as well as fir, Masson pine and other woods. Nominal fracture toughness of pre-cracks from cane cortex measured by flexibility method was 0.263 MPa m^1/2, which was less than the nominal fracture toughness value for pre-cracks from the core. When the rattan was bent, the crack in the rattan extended along with the prefabricated crack plane. Within the parenchymatic tissue, the crack extended transversely and changed its direction when the crack stretched into fiber sheath. The distribution density of vascular bundle was positively correlated with the fracture toughness.

In the post and beam structure, the post and beam play a crucial role in directly supporting and transmitting loads, thus making them essential elements in structural design. In cases where the moment resistance performance of the post-beam joint is inadequate, a shear wall and bracing are frequently installed to provide support for horizontal load on the posts and beams. The structural insulated panel (SIP) is increasingly utilized and studied as shear walls alongside light-frame timber construction, owing to its insulation properties as well as its high shear strength. In this study, when using SIP as a shear wall between post and beams, three composite wall structures were considered based on the installation location of the SIPs on the post-beam structure and lateral resistance performance of the hybrid shear wall was evaluated according to the SIP installation location. Depending on the installation location SIPs on the posts and beams, shear strength for I-SIP 150, E-SIP 150, and M-SIP 150 were 23.2, 24.6, and 26.0 kN, respectively. In case of the shear stiffness, I-SIP 150, E-SIP-150, and M-SIP 150 were found to be 4.32, 3.99, and 2.74 kN/mm, respectively.