Herein, a novel flame retardant, 2,2,4,4,6,6-[1-(9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-1-di(4-aminophenyl)-1-methyl)]-cyclotriphosphazene, named DPHP, was synthesized and used to flame retard the unsaturated polyester resin (UPR). On the one hand, the phosphorus element in DPHP can interrupt the chain reaction by the P-containing free radicals generated during combustion in the gas phase, and the P-containing compounds generated can catalyze the matrix into char in the condensed phase, and make the generated char denser and more continuous than pristine UPR. On the other hand, the nitrogen element in DPHP can produce non-flammable gas during combustion, and dilute oxygen and combustible volatile products, so DPHP played a role in the gas and condensed phases, improving the fire safety of the UPR matrix. As a result, 10DPHP/UPR showed better flame retardancy with a limiting oxygen index of 29.6%, and the peak heat release rate (pHRR) and total heat release rate (THR) decreased by 63.86% and 30.65%. The flame-retardant mechanism of DPHP in UPR was analyzed and discussed.
This paper aims to develop a high precision variable dielectric constant capacitor detector for mechanical sand water content testing. The non-contact on-line test method can effectively solve the problems of low repeatability of test data, large hysteresis error and poor linearity due to the non-uniform water content. In terms of hardware, CAV444 is a high-precision integrated chip, which matches the corresponding test circuit. The system communicates with PC through serial interface and implements the man-machine interface of PC system based on VS. Secondly, the distribution map method is used to measure the water content of machine-made sand, and the error analysis is carried out. The test shows that the output of the capacitive hygrometer is 0-5 V. The delay time should not exceed 0.15%. The repetition rate was within 0.33%. The measurement accuracy of this method is less than 3.52%.
The hydraulic system of the deep-sea miner is designed, the control model of the hydraulic system is established, the control effect of the conventional PID controller and the fuzzy PID controller on the suspension system is compared and analyzed, and the stability of the hydraulic system is simulated and analyzed.
The current engineering construction quality control using the installation of sensors and other ways of quality control, not only the efficiency is affected, and can't trace the quality problems of each construction link, resulting in a delay in the construction period, the quality problem rectification effect is poor. Aiming at the defect of appeal, the real-time quality control method of assembly building engineering based on BIM technology is studied. According to characteristics of prefabricated building construction process, analysis of factors influencing the modular construction quality. The appropriate influencing factors were selected to establish the quality control index system, and the entropy weight method was used to determine the index weight. According to the index weight, the application of BIM technology design in different construction link quality control plan, realize the real-time control of the quality of engineering. In the actual case application, the effective rectification rate of project quality problems is as high as 98.5% on average after using BIM technology, and the construction period is effectively shortened.
