Research on Design Method of Long-life Asphalt Pavement

In recent years, the problem of early damage of asphalt pavement has been basically solved, and the service performance has been improved, but there are still some deficiencies in design life and service life. This paper investigates the long-life asphalt pavement structure, analyzes the design method of asphalt mixture, and summarizes the pavement design theory and related software. The long-life asphalt pavement with semi-rigid base, flexible base and combined base structure has been designed by four method, including typical load, Per-Road, D50-2006 and D50-2017. Four methods were compared by designing long-life pavements with semi-rigid base and flexible base. The results show that the proposed asphalt pavement structure can meet the requirements of Per-Road, typical load design and D50-2006. However, D50-2017 has higher requirements for the bending and tensile fatigue life of the base layer and requires a thicker base layer. When d50-2017 is used to design flexible base pavement, the fatigue life of asphalt layer should be the main control index, and the fatigue life of sub base course should be the main control index in other pavement de-sign. It remains to be seen whether the proposed highway structure can achieve the design goal of long-life asphalt pavement

Research on Design Method of Long-life Asphalt Pavement

In recent years, the problem of early damage of asphalt pavement has been basically solved, and the service performance has been improved, but there are still some deficiencies in design life and service life. This paper investigates the long-life asphalt pavement structure, analyzes the design method of asphalt mixture, and summarizes the pavement design theory and related software. The long-life asphalt pavement with semi-rigid base, flexible base and combined base structure has been designed by four method, including typical load, Per-Road, D50-2006 and D50-2017. Four methods were compared by designing long-life pavements with semi-rigid base and flexible base. The results show that the proposed asphalt pavement structure can meet the requirements of Per-Road, typical load design and D50-2006. However, D50-2017 has higher requirements for the bending and tensile fatigue life of the base layer and requires a thicker base layer. When d50-2017 is used to design flexible base pavement, the fatigue life of asphalt layer should be the main control index, and the fatigue life of sub base course should be the main control index in other pavement de-sign. It remains to be seen whether the proposed highway structure can achieve the design goal of long-life asphalt pavement

Diversity and antibacterial and antioxidant activities of fungal endophytes from the roots of Eucalyptus deglupta

In this study, 45 endophytic fungal strains were isolated from the roots of Eucalyptus deglupta. Among them, 16 distinct strains were identified and classified into 14 different genera (Celoporthe, Aspergillus, Castanediella, Chaetomium, Biscogniauxia, Sordariales, Pestalotiopsis, Clitopilus, Cylindrocladiella, Calonectria, Trichoderma, Xylaria, Neofusicoccum and Pleosporales) according to their morphological characteristics and molecular information. The genera Aspergillus and Calonectria were the dominant endophytic fungi in the roots of E. deglupta. In addition, the antibacterial and antioxidant activities of the 16 endophytic fungi isolated from the roots of E. deglupta were evaluated. All the strains displayed inhibitory activities against Agrobacterium tumefaciens, Bacillus subtilis, Escherichia coli, and Xanthomonas vesicatoria. Strains Edf-1 to Edf-4, Edf-11 and Edf-12 demonstrated strong inhibitory activity against R. solanacearum with plaque diameters between 5 and 10 mm. The crude extract of Edf-14 had inhibitory activity against all tested bacteria. Five strains, Edf-1 to Edf-5, demonstrated a strong scavenging capacity for 2,2-diphenyl-1-picrylhydrazyl (DPPH), with IC50 values of 0.26 ± 0.04, 0.11 ± 0.03, 0.20 ± 0.05, 0.10 ± 0.04 and 0.14 ± 0.02 mg/mL, respectively. Hence, endophytic fungi isolated from the roots of E. deglupta showed antibacterial and antioxidant activities, providing a theoretical foundation for further isolation and identification of specific active components

Rhodium-Catalyzed Highly Regioselective Hydroaminomethylation of Styrenes with Tetraphosphorus Ligands

The highly linear-selective hydroaminomethylation of styrenes is very challenging. Herein, an efficient, highly chemoselective, and linear-selective hydroaminomethylation (l/b up to >99:1) of styrenes using Rh(nbd)₂SbF₆ with a pyrrole-based 3,3′,5,5′-substituted tetraphosphorus ligand is documented. This is in sharp contrast to other available processes leading to branched amines and provides a novel atom economic approach to 3-arylpropylamines

Cascade Synthesis of Fenpiprane and Related Pharmaceuticals via Rhodium-Catalyzed Hydroaminomethylation

A novel rhodium catalytic system with Naphos as ligand was developed for an efficient hydroaminomethylation of 1,1-diphenylethene under relatively mild conditions. This will allow for an atom-economic and environmentally benign synthesis of fenpiprane and related pharmaceuticals

Remediating Potentially Toxic Metal and Organic Co-Contamination of Soil by Combining In Situ Solidification/Stabilization and Chemical Oxidation: Efficacy, Mechanism, and Evaluation

Most soil remediation studies investigated single contaminants or multiple contaminants of the same type. However, in field conditions, soils are often contaminated with potentially both toxic metals and organic pollutants, posing a serious technical challenge. Here, batch experiments were conducted to evaluate the performance of combining in situ solidification/stabilization (ISS) and in situ chemical oxidation (ISCO) for the simultaneous removal of aniline (1000 mg/kg) and Cd (10 mg/kg). All four tested ISS amendments, especially quick lime and Portland cement, promoted in situ chemical oxidation with activated persulfate in contaminated soil. Combined ISS/ISCO remediation effectively removed aniline and reduced the bioavailable Cd content at optimal initial persulfate and ISS amendment concentrations of 1.08 mol/kg and 30 wt% with a seven-day curing time, and significantly reduced leaching. Persulfate inhibited the reduction of the bioavailable Cd content, and ISS amendment with persulfate did not synergistically remediate Cd in co-contaminated soil. Strong alkalinity and high temperature were the main mechanisms driving rapid pollutant removal and immobilization. The reaction of CaO with water released heat, and Ca(OH)2 formation increased the pH. The relative contributions of heat vs. alkaline activation, as well as the contaminant removal efficiency, increased with ISS amendment CaO content. Combined treatment altered the soil physicochemical properties, and significantly increased Ca and S contents. Activated persulfate-related reactions did not negatively impact unconfined compressive strength and hydraulic conductivity. This work improves the selection of persulfate activation methods for the treatment of soils co-contaminated with both potentially toxic metals and organic pollutants