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The purpose of this paper is to get hold of the main influence factors of the investment efficiency of environmental governance and control them to improve its efficiency sensitively and employ full use of the investment of environmental governance.

The assessment index system of the investment efficiency of environmental governance is built. Its investment efficiency is assessed based on data envelopment analysis (DEA). The influence degree on the efficiency between each assessment index is calculated by the grey incidence degree analysis method to find the key influence factors. The efficiency of the investment in the environmental governance can be improved by managing and controlling the key factors.

The results prove that it is available by the data of 14 cities in Shandong Province in 2008. The key influence factors of the investment efficiency of the environmental governance are: total investment in the treatment of environmental pollution (F₁); industrial soot removal (F₃); industrial wastewater meeting discharge standards (F₂); and the volume of garbage disposal (F₉).

The method exposed in the paper can be used to solve investment efficiency problem of the environmental governance of the other provinces, or other years and even other countries.

The paper succeeds in solving investment efficiency problem of the environmental governance by DEA and grey incidence degree analysis method.

The particle damper is an efficient vibration control device and is widely used in engineering projects; however, the performance of such a system is very complicated and highly nonlinear. The purpose of this paper is to accurately simulate the particle damper system properly, and help to understand the underlying physical mechanics.

A high-fidelity simulation process is well established to account for all significant interactions among the particles and with the host structure system, including sliding friction, gravitational forces, and oblique impacts, based on the modified discrete element method. In this process, a suitable particle damper system is modeled, reaction forces between particle aggregates and the primary structure are incorporated, a reasonable contact force model and time step are determined, and an efficient contact detection algorithm is adopted.

The numerical results are further validated by both special computational tests and shaking table tests, with good agreements to the experimental results. The method is shown to be effective and accurate to simulate the particle damper system.

The approaches described in this paper provide an efficient numerical way to investigate complex particle damper systems.

There are three purposes in this paper: to verify the importance of bi-directional fluid-structure interaction algorithm for centrifugal impeller designs; to study the relationship between the flow inside the impeller and the vibration of the blade; study the influence of material properties on flow field and vibration of centrifugal blades.

First, a bi-directional fluid-structure coupling finite element numerical model of the supersonic semi-open centrifugal impeller is established based on the Workbench platform. Then, the calculation results of impeller polytropic efficiency and stage total pressure ratio are compared with the experimental results from the available literature. Finally, the flow field and vibrational characteristics of 17-4PH (PHB), aluminum alloy (AAL) and carbon fiber-reinforced plastic (CFP) blades are compared under different operating conditions.

The results show that the flow fields performance and blade vibration influence each other. The flow fields performance and vibration resistance of CFP blades are higher than those of 17-4PH (PHB) and aluminum alloy (AAL) blades. At the design speed, compared with the PHB blades and AAL blades, the CFP blades deformation is reduced by 34.5% and 9%, the stress is reduced by 69.6% and 20% and the impeller pressure ratio is increased by 0.8% and 0.14%, respectively.

The importance of fluid-structure interaction to the aerodynamic and structural design of centrifugal impeller is revealed, and the superiority over composite materials in the application of centrifugal impeller is verified.