Very little is known about mixed polybrominated/chlorinated dibenzo-p-dioxins and dibenzofurans (PBCDD/F) in industrial thermal processes. In this study, the occurrences and characteristics of PBCDD/F from various incineration and metallurgical processes were investigated. In addition, PBCDD/F analytical protocols based on HRGC/HRMS were developed and optimized. The sum of isomer group concentrations ranged from 1.7-3740 pmol Nm -3 for PBCDF and 0.2-582 pmol Nm -3 for PBCDD. For some metallurgical industries, the amounts of PBDD/F and PBCDD/F emitted were similar to or even higher than the amounts of PCDD/F. The sources of bromine and brominated-precursors in these processes should be evaluated. The PBCDD/F characteristics investigated included isomer group patterns, ratio of bromine and chlorine incorporated in PBCDD/F, and ratio of halogenated furans to dioxins. Lower brominated PBCDD/F were binomially distributed. But in some cases, the concentrations of higher brominated PBCDD/F were much higher than predicted from the binomial distribution. The formation mechanisms of PBDD/F, PBCDD/ F, and PCDD/F in these processes were also evaluated.
This paper discusses and analyses precise hydraulic pressure control of VVVF hydraulic system. The mathematical model of system is established and PID control law is adopted. Numerical simulation of PID controller is carried out with the SIMULINK of MATLAB. In the non-linear, time-varying VVVF hydraulic system, however, conventional PID control often cannot satisfy the request of precise pressure control. This paper applies biology immune adjust principle and fuzzy control theory to design fuzzy immune self-adaptive controller which is used in VVVF hydraulic system, and gets favorable control effect. The MATLAB-based simulations show that fuzzy immune PID is effective in improving the control performance of VVVF hydraulic system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.