Synthesis of 2,2,4,4-Tetramethyl-N,N′-bis(2,6-dimethylphenyl)cyclobutane-1,3-diimine, a Unique Compound from Arundo donax, and Its Analogues to Test Their Antifeedant Activity Against the Boll Weevil, Anthonomus grandis
2,2,4,4-Tetramethyl-N,N′-bis(2,6-dimethylphenyl) cyclobutane-1,3-diimine (1), which was isolated from the Thai plant Arundo donax as an antifeedant against the boll weevil (Anthonomus grandis), and its analogues (9-13) were synthesized and shown to possess no remarkable antifeedant activity of practical interest.
Boll weevil antifeedants from Arundo donax.
Abstract Triacontanol, tricin and tetramethyl- N,N -bis(2,6-dimethylphenyl)cyclobutane-1,3-diimine, newly reported from Arundo donax , showed significant antifeedant activity against the boll weevil, Anthonomus grandis . A common mixture of phytosterols was also obtained from the aerial parts of the plant, but none showed any antifeedant activity.
Experimental study on bond behavior between high-strength grout and deformed steel bars
Abstract Engineers use high-strength grout to connect precast concrete members for its low shrinkage and good fluidity. This paper designed 87 central pull-out specimens using the control variable method to investigate the influence of factors on the rebar-grout bond property such as compressive strength, steel grade, bar diameter, transverse stirrups, and bond length. The test result showed that improving grout compressive strength (85.8 MPa–122.7 MPa) cannot improve the bond strength, which was different from the previous conclusions of concrete pull-out tests. Simplified formulas were presented for calculating the characteristic values of bond strength, residual strength, peak slip, and relative slip of load-holding platform based on parameter analysis. Then, a constitutive model was proposed to predict the full-range bond stress-slip curve of high-strength grout and steel bar specimens from bearing to failure. Finally, FEA models were established to evaluate the applicability and accuracy of the constitutive model.