With the globalization of economic development, the application of mathematics throughout the various areas of probability and statistics is the use of modern engineering, social and economic research is a core of mathematics. Mathematical modeling provides a new way of thinking to the economic problems from the economic decision-making issues mathematical model of probability and statistics in the economic field.
To decrease the influent load of the wastewater treatment system and increase the overall ability of the wastewater treatment plant to meet the demand for 15% production expansion of the enzyme preparations factory, the purpose of this study was set to decrease COD concentration of the centrate from the sludge treatment system. Three orthogonal experiments and follow-up analysis of experiment results identified the significant impacts factors on COD concentration of the centrate. Afterwards, four full factorial experiments were designed to obtain a set of optimum parameters combination on the condition that no GMO was detected in the dewatered sludge.
The objective of this work is to conduct feasibility studies on water treatment for boiler feeding water use from treated municipal wastewater effluent using a pilot dual continuous ultrafiltration - reverse osmosis (CUF/RO) membrane process with the capacity of 15m3/h. A CUF membrane from HYDRAcap and LFC3-LD RO membrane were used in this study. The CUF unit and RO unit were operated at over 97% and 75-80% water recovery, respectively. The results indicate that CUF process is not only capable of reducing organic and nutrient pollutants but also achieves a silt density index (SDI) less than 2, turbidity of less than 0.47NTU which is suitable for RO treatment. Rejection of the RO unit in terms of average conductivity, COD, hardness, alkaline, NH4+-N, TN, TP were higher than 98.2%, 97.9%, 99.8%, 97.9%, 93.9%, 95.1% and 75%, respectively. Other parameters also can match the quality of high-grade water for use in the boiler industry except pH. Finally, a cost comparison between dual membrane and ion-exchange process showed annual savings of more than 33000000 CNY can be possible.
Concerning the uneven distribution of energy in Chinas regional power grid, power of big energy base should be transmitted through long distance. Therefore, calculating available transfer capability (ATC) of large interconnected grid is necessary. However, it is difficult to collect the needed data, so ATC of the large interconnected grid cannot be calculated directly. To solve these problems, this paper presents a decomposition calculation method to calculate ATC of the large interconnected grid. The basic principles are: According to the executive partition, the large interconnected grid is divided into several subsystems, of which ATC can be calculated directly and easily. Then, according to series or parallel combination between the subsystems, ATC of the large interconnected grid can be calculated indirectly by the obtained ATC of subsystems. The series and parallel ATC probabilistic calculation models are established, used for synthetizing ATC of the subsystems. Illustrations verify the correctness and feasibility of the calculation method.
On-off of the standby system is an important factor that influences the performance of the production system. A dual threshold control strategy based on the on-off control of the standby system is proposed for the optimal control of the two-stage production system for which the last stage has stochastic production capacity. A control parameters optimization model is built with the objective of minimizing the total production cost, and a genetic algorithm is adopted to resolve the optimization problem. Finally, an example is taken to validate the effectiveness of the proposed dual threshold control strategy and the parameter optimization algorithm.
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