No abstract

Undesired lateral force inevitably exists in a MacPherson suspension system, which is liable to damper rod's side wear and promotes the damper's inner friction decreasing the ride performance from the suspension system. Substituting a new side load spring with curved centerline for the conventional coil spring has been proven able to solve these problems and Multi-body Dynamics combining with Finite Elements Analysis may be an efficient method in optimizing its design. Therefore, taking a passenger car as example, a detailed multi-body dynamics model for the suspension system is built to simulate forces exerted on the damper and the minimization of its lateral component is selected as the design target for the spring. When the structure optimization of the side load spring is performed using FEA software ANSYS, its vertical and lateral elastic characteristics, supported by test data, are analyzed. After importing FEA results back to the suspension system, the dynamics simulation can be performed to validate the optimization result.

A kinetic model was proposed to describe fluid catalytic cracking of vacuum gas oil on a molecular level by the structure-oriented lumping method. The structure-oriented lumping method was applied to construct a feedstock matrix and reaction networks. All totaled, 391 kinds of molecules were selected to represent feedstock composition, and a non-linear least squares method was used to calculate the content of each kind of molecule. Sixty-six kinds of reaction rules were established to produce the networks for the reactions of vacuum gas oil. Product distribution and properties can be predicted by the structure-oriented lumping model, which are in good agreement with the experimental data.

The design of French VFCWs leads to the formation of a sludge layer at the surface of the first filters due to the retention of suspended solids from the percolation of unsettled wastewater. This layer plays a major role in the system but still little is known on its characteristics and evolutions. In this study, suspended solids and sludge deposits sampled from two French VFCW plants were analyzed by different methods in the objective to assess the evolution of particulate organic matter (POM) along the treatment chain and within the sludge layer, and identify relevant analytical indicators of these phenomena. The treatment chain included an aerobic trickling filter followed by FeCl injection and two successive stages of filters. Thermal analyses showed that OM contents of suspended solids decreased along the treatment chain. POM in inflow suspended solids was predominantly composed of reactive, biodegradable compounds which were partly hydrolyzed and mineralized notably at the trickling filter stage. 3D fluorescence spectra collected from aqueous POM extracts confirmed the evolution of organic matter from low-molecular reactive compounds to more complex and stable structures such as humic-like substances. FTIR confirmed the mineralization of POM's reactive constituents along the treatment chain by the decrease in the intensities of the characteristics bands of aliphatic compounds or proteins, and its humification in the sludge deposits through the relative increase of the bands at 1634cm (v) and 1238cm (δ and/or δ). Isotopic ratios δH/H and δN/N were found to be good indicators of POM evolutions. The higher values of δH/H and δN/N ratios measured in sludge deposits as compared to inflow suspended solids were related to POM humification and to microbial processes of POM hydrolysis and mineralization, respectively.