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.

With the rapid growth of shield-discharged soil (SDS), there is an increasing demand for effective recycling and transformation methods. This study aims to develop an alkali-activated controlled low-strength material (CLSM) by utilizing ground granulated blast furnace slag (GGBFS) and fly ash (FA) as precursors, SDS as fine aggregate, and sodium hydroxide (NaOH) solution as an activator. The Box-Behnken design (BBD) within the response surface methodology (RSM) framework was employed, considering liquid-to-solid ratio, alkali equivalent, aggregate-to-binder ratio, and foam agent content (FC) in SDS as key factors. Regression models were constructed to analyze the effects of these factors on flowability, bleeding rate, setting time, compressive strength, elastic modulus, and water absorption. The results confirmed the effectiveness of RSM in determining optimal conditions for material performance. In addition, microscopic analyses were conducted to explore hydration products, microstructural characteristics, and pore distribution. The findings revealed that the fresh density of the CLSM ranged from 1460 to 1740 kg/m(3), classifying it as a low-density material. The 28-day compressive strength varied from 1.837 to 7.884 MPa, while the setting time ranged between 1.2 and 5.6 hours. These properties comply with the ACI 229 standard and are suitable for practical applications. Interestingly, when the aggregate-to-binder (A/B) ratio was between 0.2 and 0.4, increasing the ratio did not lead to a consistent reduction in mechanical properties. Instead, the properties initially decreased and then improved. Moreover, an increase in foam agent content (FC) extended the setting time and reduced mechanical strength. The correlation coefficients of all models exceeded 0.98, with a coefficient of variation below 10 % and a signal-to-noise ratio greater than 4, demonstrating strong reliability and accuracy of the models. Additionally, the average relative error between predicted and experimental values in six scenarios was under 6 %, validating the feasibility of optimizing the design of alkali-activated CLSM using RSM. The formation of Ca(OH)(2) crystals facilitates early strength development, resulting in final cementitious materials reticular, fibrous C-S-H, C-A-H, and other gel-like hydration products. Calcium promotes the formation of gels such as C-S-H, shortening the setting time and enhancing microstructural density. This study provides valuable insights for optimizing the design of alkali-activated CLSM containing SDS, thereby expanding methods for utilizing construction and demolition waste.

The development of restoration technology and meadows, improvement of run-down pastures, and productivity improvement of old crops of perennial grasses is an urgent problem in agriculture. The tillage traction force in seeder designing and manufacturing is an important indicator of energy efficiency. The objective of this work is to reduce traction force and ensure seeding depth uniformity by justifying the optimal chisel parameters of a grain-fertilizer-grass seeder for direct seeding in sod. The Box-Behnken method was applied to investigate the traction force dependence on the seeder velocity, seed embedding depth, chisel width, and mounting angle. The obtained optimal parameters of coulters were justified by the finite element method. Structural and technological parameters were checked using the smoothed-particle hydrodynamics method on the deformation and wear of the seeder working body. The revealed optimal coulter parameters were as follows: chisel width was 20-20.97 mm, chisel length was 145-148.9 mm, mounting angle was 75 degrees-81.6 degrees, and achieved minimum traction force was 720 N. These parameters ensure the quality of grass seed embedding in the sod. The theoretical data of traction force (8.27-8.39 kN) are in accordance with the experimental (8.28-8.63 kN) data under field conditions. These findings are efficient in agrotechnical and mechanical predictions regarding the occurrence of chisel residual stresses and the working lifetime of the part.

Several studies have explored the potential of waste marble powder (WMP) and lime (LM) as solutions for issues associated with clayey soils. While WMP enhances mechanical properties and addresses environmental concerns, LM effectively improves soil characteristics. This research investigates the efficacy of LM and WMP, both individually and in combination, in addressing challenges specific to clayey soils in Bouzaroura El Bouni, Algeria. These soils typically exhibit low load-bearing capacity, poor permeability, and erosion susceptibility. LM demonstrates promise in enhancing soil properties, while WMP not only addresses environmental concerns but also enhances mechanical characteristics, providing a dual benefit. The study utilizes a three-variable experiment employing Response Surface Methodology (RSM) Box-Behnken Design, with variations in clay content (88%-100%), LM treatment (1.5%-9%), and WMP inclusion (1.5%-9%). Statistical analysis, including ANOVA, reveals significant patterns with p-values <5%. Functional relationships between input variables (clay, LM, and WMP) and output variables (cohesion, friction angle, and unconfined compressive strength) are expressed through high determination coefficients (R-2 = 99.84%, 77.83%, and 96.78%, respectively). Numerical optimization identifies optimal mixtures with desirability close to one (0.899-0.908), indicating successful achievement of the objective with 88% clay content, 3% LM, and 6% WMP. This study provides valuable insights into optimizing clay soil behavior for environmental sustainability and engineering applications, emphasizing the potential of LM and WMP as strategic additives.

目的制备羟基积雪草酸固体脂质纳米粒（madecassic acid solid lipid nanoparticles,MA-SLN）并对其体外释药行为进行研究。方法 （1）采用溶剂乳化挥发-高压均质法制备羟基积雪草酸固体脂质纳米粒,以包封率、载药量为指标,通过Box-Behnken响应面法筛选制备羟基积雪草酸固体脂质纳米粒的最优工艺及处方,并通过包封率、微观形态、粒径分布和Zeta电位对其质量进行评价。（2）配制羟基积雪草酸溶液为对照考察两种剂型中羟基积雪草酸的体外释放及透皮行为。结果 （1）优化处方为羟基积雪草酸230.87 mg,山嵛酸甘油酯300 mg,P188与T-80用量比为1∶1。羟基积雪草酸固体脂质纳米粒透射电镜下呈球状或类球状,平均粒径为（226.8±11.2）nm,PDI为（0.19±0.08）,Zeta电位为（-25.11±3.24）mV。呈淡蓝色乳光,包封率84.1%,载药量21.5%。（2）两种剂型中羟基积雪草酸的体外累积释放24 h是75.63%,而溶液剂在4 h时已达97.36%;经皮稳态渗透速率分别为0.9754和0.6185μg·cm-2