This study investigates the impact of Washingtonia palm biomass on clayey soil shear strength using experimental and statistical approaches. The research examines the effects of Washingtonia filifera leaf powder, trunk fibres, and biochar derived from the rachis (pyrolyzed at 400 degrees C) on the properties of reinforced soil. Factors investigated include additive percentage (1%, 3%, 5%), sodium hydroxide (NaOH) solution concentration (2%, 5%, 8%), and immersion time (1 h, 4 h, 7 h). A Box-Behnken experimental design with 15 trials was employed to prepare soil-powder, soil-fiber, and soil-biochar composites. Direct shear tests were conducted on reinforced and unreinforced specimens to determine shear strength, cohesion, and friction angle. Results showed significant improvement in shear strength for all additives under normal stresses of 100, 200, and 300 kPa. Increasing additive content enhanced both cohesion and friction angle. Biochar-reinforced soil yielded the highest cohesion of 112 kPa, followed by fiber-soil with 70 kPa and powder-soil with 69 kPa, compared to 15 kPa in unreinforced soil. Additionally, soil mixed with powder, fiber, and biochar exhibited friction angle improvements of 57%, 93%, and 110% respectively, from an initial 13.5 degrees in unreinforced soil. Regression models were developed for shear stress responses using the Response Surface Methodology, and the influence of each parameter on the models was determined using ANOVA analysis. Using a combined approach of response surface methodology (RSM) and the desirability function, optimal values (5% of additives, 5% NaOH concentration, and 1 h of immersion time) were determined. These optimal values agreed well with the experimental results. It can be concluded that the inclusion of the three additives has positive benefits on the mechanical properties of the reinforced soil, with biochar demonstrating the most significant improvements.

Tractors are essential for many farming tasks but cause high vibrations that lead to operator discomfort and fatigue. This study examines how different tractor settings during tillage operations affect Hand-Arm Vibration (HAV). The settings tested were speed (0.6, 0.7, 0.8 m/s), draft setting (2, 4, 6 kN), and tillage depth (0.10, 0.12, 0.14 m), following ISO 5349-1:2004 standards. The Taguchi L27 array for designing the experiments, Response Surface Methodology (RSM) to see how different settings affect the results of HAV responses along the x, y, and z axes for each experiment. Experiments showed that vibrations were highest along the z-axis. Rotavation caused more HAV than harrowing and cultivation. As speed increased, daily HAV exposure also rose significantly. Analysis showed that speed and draft setting had a major impact on HAV levels. The study used different models to predict HAV, finding the quadratic model to be the most accurate. Optimal settings to minimize HAV were a speed of 0.8 m/s, draft setting of 2 kN, and tillage depth of 0.14 m. An artificial neural network (ANN) model also predicted HAV accurately with just a 2 % error. The findings suggest that the ANN model effectively predicts HAV under various tractor settings with constrain to the selected input setting. Relevance to the Industry: This research highlights the measures to reduce hand-transmitted vibration by optimizing the input (riding) parameters among tractor operators, which offers to improve the health and safety of users and reduce fatigue in actual farm conditions. In addition, the ANN model helps predict the HAV response under different input (riding) conditions. Ultimately, it is beneficial for the manufacturers and agriculture practitioners to optimize the tractor design and usage, ensuring safer and more efficient farm activities.

The study investigates the mechanical requirements for harvesting coriander (Coriandrum sativum L.) by analyzing static and dynamic cutting forces for three distinct varieties: SIMCO, GCr1, and GCr2. Through controlled laboratory experiments, the static cutting force was measured using a texture analyzer across variations in blade speed (2, 4, 6, 8, and 10 mm/s), stem number (1-5), cutting height (50, 75, 100, 125, and 150 mm), and moisture content (23 %, 30 %, and 37 %). The static cutting force for SIMCO was found to be the highest (151.6 N), followed by GCr1 (145.68 N) and GCr2 (140.48 N), primarily due to stem structure and diameter differences. The dynamic cutting force was also measured in the indoor soil bin using a reciprocating cutter bar by simulating the field conditions at varied forward speeds (0.3, 0.6, 0.9, and 1.2 m/s), cutter bar speeds (2, 8, 14, and 20 strokes/s), and cutting heights (50, 75, 100, 125, and 150 mm). For dynamic cutting, the SIMCO variety required an average maximum force of 33.14 N, which was 6.85 % and 7.06 % higher than GCr1 and GCr2 respectively. The dynamic cutting forces were influenced most significantly by cutter bar speed and forward speed, with optimal cutting achieved at 20 strokes/s cutter bar speed and 0.3 m/s forward speed. Response Surface Methodology (RSM) models with R2 values above 0.99 effectively predicted both static and dynamic cutting forces, indicating strong model adequacy and providing detailed insights into the interactions between parameters. The analysis revealed that the number of stems and blade speed were the primary influencers on static cutting force, while the dynamic force was most affected by cutter bar speed and forward speed. This study highlights the importance of customized parameter settings to enhance harvester efficiency, reduce energy consumption, and minimize seed damage during harvest.

Biodegradable plastic is the preferred alternative to traditional plastic products due to its high degradability, decreased dependence on fossil sources, and decreased global pollution according to the accumulation of traditional plastic. In the current study, the optimization of biodegradable plastic synthesis was studied using biomass reinforcement materials. The reinforcement material is cellulose extracted from sawdust to prepare biodegradable plastic using the casting method. Response surface methodology using Box-Behnken Design is used to optimize the main parameters affecting the tensile strength and elongation at the break of the biodegradable plastic. These parameters are cellulose fiber addition, acetic acid addition, and the mass ratio of glycerol to starch. The maximum tensile strength and elongation were obtained at 4.45 MPa and 5.24%, respectively, using 5% cellulose fiber addition and 11.24% acetic acid addition with a 0.266 w/w glycerol to starch mass ratio. Various analyses were performed on the produced biodegradable plastic, including FTIR, SEM, and thermal stability. The biodegradability of the produced biodegradable plastic after immersing the soil for 10 days was about 90% higher than the traditional plastics. The produced biodegradable plastic has a moisture content of 4.41%, water absorption of 81.5%, water solubility of 24.6%, and alcohol solubility of 0%. According to these properties, the produced biodegradable plastic can be used in different industries as a good alternative to traditional plastics.

Rubber-sand mixtures (RSM) have the potential to be used as eco-friendly geotechnical materials for the reinforcement of roadbeds and other projects. By a series of monotonic direct shear tests under normal cyclic loading (NCMDS), the impact of rubber contents, initial stresses, stress amplitudes, and loading frequencies on the shear properties of the geogrid and RSM interface was studied. Shear models for pure sand and RSM were formulated using PFC3D, and the mesoscopic behaviors during the shearing were investigated. The findings indicated that the interface exhibited prominent softening characteristics. It was observed that a lower rubber content corresponded to a more pronounced softening phenomenon. For a given rubber content, with a rise in frequency, there was a decline in both the peak stress and stress fluctuation amplitude of the interface, and the overall dilatancy decreased. The RSM had slightly more contact points than pure sand, and the count of contact points during the peak state surpassed that during the valley state. Throughout the shearing, the coordination showcased cyclic fluctuations. The coordination near the interface initially diminished, then gradually leveled out, mirroring the macroscopic dilation effect. Under cyclic loading, the kinetic energy of particles exhibited more pronounced fluctuations compared to the damping energy, and the damping energy in RSM exceeded that in pure sand.

The ceramic industry produces a significant volume of ceramic waste (CW), representing around 20-30% of its the entire output. The waste mostly comes from challenges noticed in the manufacturing process, overproduction, and damage to products. Considering the substantial worldwide production of ceramics, it is crucial to efficiently handle and recycle this waste to promote sustainability efforts. This study explores the conversion of ceramic waste into fine aggregates suitable for the production of paver blocks. Currently, a variety of assessments are being conducted to determine the effectiveness of these enhanced paver blocks. The evaluations involve aspects like compressive strength, water absorption (WA), dry density, flow table measurements, ultrasonic pulse velocity (UPV), and rebound hammer tests. The results indicate that replacing natural aggregates with up to 30% CW significantly improves compressive strength (CS) and Rebound results from tests. This study provides useful information into optimising the content of CW in paver blocks, contributing to the development of sustainable and economical construction materials. Furthermore, it focusses on minimising landfill waste and preserving natural resources.

Caffeine, a significant naturally occurring alkaloid in beverages like tea and coffee, can be degraded by bacteria. Prolonged caffeine consumption can stimulate adrenal glands, cause irregular muscle activity, cardiac arrhythmias, and withdrawal symptoms such as headaches and fatigue. Beyond its health-related concerns, the environmental impact of caffeine degradation is noteworthy. Effluents from coffee industries contain high caffeine concentrations, and the discharge of such effluents into lakes poses a risk to the portability of drinking water. This study isolated a novel bacterium from agricultural soil, identified as Bacillus sp. KS38 through 16 S rRNA gene sequencing, which can metabolize caffeine as the sole carbon and nitrogen source. The bacterium exhibited Gram-positive characteristics. Response surface methodology (RSM) optimized bacterial growth conditions. The relevant parameter for the degradation of caffeine was obtained by first screening the parameters using the Plackett-Burman design. Using central composite design (CCD) and RSM, the important parameters were determined to achieve the ideal degradation conditions. The identified the ideal degradation conditions: 0.66 g/L caffeine, 0.85 g/L glucose, pH 6.83, and 20.5 degrees C. RSM predicted a bacterial growth of 0.591, which was confirmed experimentally. This bacterium has potential applications in wastewater treatment and caffeine bioremediation.

As part of the development of alternative and environmentally friendly control against phytopathogenic fungi, Burkholderia cepacia could be a useful species notably via the generation of hydrolytic enzymes like chitinases, which can act as a biological control agent. Here, a Burkholderia contaminans S614 strain exhibiting chitinase activity was isolated from a soil in southern Tunisia. Then, response surface methodology (RSM) with a central composite design (CCD) was used to assess the impact of five factors (colloidal chitin, magnesium sulfate, dipotassium phosphate, yeast extract, and ammonium sulfate) on chitinase activity. B. contaminans strain 614 growing in the optimized medium showed up to a 3-fold higher chitinase activity. This enzyme was identified as beta-N-acetylhexosaminidase (90.1 kDa) based on its peptide sequences, which showed high similarity to those of Burkholderia lata strain 383. Furthermore, this chitinase significantly inhibited the growth of two phytopathogenic fungi: Botrytis cinerea M5 and Phoma medicaginis Ph8. Interestingly, a crude enzyme from strain S614 was effective in reducing P. medicaginis damage on detached leaves of Medicago truncatula. Overall, our data provide strong arguments for the agricultural and biotechnological potential of strain S614 in the context of developing biocontrol approaches.

In the engineering practices, it is increasingly common to encounter fractured rocks perturbed by temperatures and frequent dynamic loads. In this paper, the dynamic behaviors and fracture characteristics of red sandstone considering temperatures (25 degrees C, 200 degrees C, 400 degrees C, 600 degrees C, and 800 degrees C) and fissure angles (0 degrees, 30 degrees, 60 degrees, and 90 degrees) were evaluated under constant-amplitude and low-cycle (CALC) impacts actuated by a modified split Hopkinson pressure bar (SHPB) system. Subsequently, fracture morphology and second-order statistics within the grey-level co-occurrence matrix (GLCM) were examined using scanning electron microscopy (SEM). Meanwhile, the deep analysis and discussion of the mechanical response were conducted through the synchronous thermal analyzer (STA) test, numerical simulations, one-dimensional stress wave theory, and material structure. The multiple regression models between response variables and interactive effects of independent variables were established using the response surface method (RSM). The results demonstrate the fatigue strength and life diminish as temperatures rise and increase with increasing fissure angles, while the strain rate exhibits an inverse behavior. Furthermore, the peak stress intensification and strain rate softening observed during CALC impact exhibit greater prominence at increased fissure angles. The failure is dominated by tensile damage with concise evolution paths and intergranular cracks as well as the compressor-crushed zone which may affect the failure mode after 400 degrees C. The second-order statistics of GLCM in SEM images exhibit a considerable dependence on the temperatures. Also, thermal damage dominated by thermal properties controls the material structure and wave impedance and eventually affects the incident wave intensity. The tensile wave reflected from the fissure surface is the inherent mechanism responsible for the angle effect exhibited by the fatigue strength and life. Ultimately, the peak stress intensification and strain rate softening during impact are determined by both the material structure and compaction governed by thermal damage and tensile wave. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).