Applied Mechanics and Materials Vols. 209-211

Abstract: In this paper, we presented an approach to control on the total hardness over the wastewater treatment recycling process for pulp and paper mill. The main problem, however, is the effects of Ca2+ concentration on the recycling treatment process. The experiments were conducted by using coagulation method with reagents of Ca(OH)2 addition alone and Ca(OH)2 +PAC addition respectively to control on total hardness. The samples were collected from the effluent and the influent of the biological treatment tank respectively of the wastewater treatment plant in a pulp and paper mill. The experimental results identified that the optimum reagent addition position was in the effluent of the biological treatment tank. When addition Ca(OH)2 alone, the optimum Ca(OH)2 addition amount was 2g/L, as a result, 70.1% of total hardness was removed ( from 1088.05mg/L down to 325.16mg/L), pH value was from 7.23 to 8.61, and sludge volume ratio was 9.9%. When addition PAC+ Ca(OH)2 , the optimum Ca(OH)2 addition amount was 1g/L, the optimum PAC addition amount was 300mg/L respectively, as a result, 71% of total hardness was removed( from 1088.05mg/L down to 315.25 mg/L), pH value was from 7.23 to 7.66, and sludge volume ratio was 6.5%. The effluent-quality can meet the National Industrial Wastewater Recycling Standard on the total hardness of 450 mg/L requirement. The reagents of Ca(OH)2 +PAC had many advantages over Ca(OH)2 alone , such as less sludge quantity, high density of sludge, small volume of sludge, and less addition of reagents and so on.

Abstract: The main phenomenon of coagulation is that particles aggregate to form flocs. In this paper, the formation of cluster was simulated on computer in 2-dimensional space using cluster -cluster aggregation model and the factors of effect was studied using fractal theory.The effect of sticking probability, sticking position , motion trajectory particle, diffusion coefficient and particle number concentration have been obtained.

Abstract: Toxicity of organophosphorus pesticide and the use of non-standard, which was the main factor of soil pesticides pollution, directly or indirectly harm human health. This study screened three wild species of bacteria, from the soil contaminated by pesticides in long-term, and respectively name as A1, A2 and A3. According to the bacterial 16S rDNA gene sequence analysis, combining with bacterial morphology, physiological and biochemical experiment results, and referring to "Berger bacterial identification manuals (eighth edition)", identified the three strains as Bacillus Branch, Clostridium microorganisms. A1, A2 and A3 were respectively Bacillus pasteurii, Clostridium butyricum and Clostridium acetobutylicum. Through the strain’s degradation and tolerability experiment to parathion-methyl, it turned out that the three strains reached the highest degradation rate in 12h, which was 73.04%, 78.05% and 85.51%, respectively.

Abstract: The effectives of pH value, contact time，sorbent dose and different initial concentration were analyzed to study the properties of the adsorption of uranium in wastewater by clay. The results show the highest adsorption capacity was obtained around neutral pH.The amount adsorbed of uranium on clay increase rapidly with increasing initial uranium concentration, but the removal rates of uranium are declined.Clay has a good adsorption capability to uranium with 18.25mg/g of adsorption capacity. The adsorption data on clay are followed by both Langmuir and Freundlich models and the results are well described by Langmuir isotherm. The pseudo-second-order kinetic model is more appropriate for the sorption process.

Abstract: To reduce the aerodynamic drag coefficient of a heavy-duty commercial truck made in China, the aerodynamic characteristics of models with additional devices are researched by adopting numerical simulation and taking a certain made-in-china truck model as research object. The mechanism and the effect of reduction of drag coefficient are analyzed and the optimization of model is gained based on contrast to the drag coefficient of base model. The results indicate that the drag coefficient descends in the most degree after roof fairing of cab is applied and the shape of roof fairing has a great influence on drag. The grille and separator can reduce drag coefficient. The research results can reduce the drag coefficients and provide the theoretical references for energy conservation and emission reduction of heavy-duty trucks

Abstract: Based on a new type of electro-hydraulic brake system of electric vehicle, the operating principle was studied. A model of hydraulic brake system and corresponding control strategy were built with the co-simulation platform of AMESim and MATLAB. The impact factors of brake pressure change rate were analyzed theoretically. The influences of the main hydraulic parameters were analyzed through simulation, such as volume of brake fluid, type of pipe, ABS valve and brake clearance. The results provide a theoretical basis for the accurate control of wheel cylinder pressure.

Abstract: Based on overlapping grid, two cars were simulated when lane-changed overtaking and the aerodynamic characteristics of two cars were achieved. By analysis the coefficients of side force and yawing moment and flow field around two cars when two cars’ position changed the flow motivation and rules of interference each other were researched. The conclusions can provide the theoretical foundation for the research of transient overtaking.

Abstract: An energy storage car driven by gravitational potential energy was designed. The car could avoid the fixed obstacles set on the track when running. It only uses the gravitational potential energy as power source and doesn’t need to use any other forms of power source. The overall design of the car was completed from some aspects of the steering system, energy storage system and transmission system etc. The cam mechanism is to realize steering of the car. Vortex coil spring is to realize the energy storage in the process of weight falling. Transmission system of the car is composed of fixed pulleys, gear mechanisms and the ratchet mechanisms. Experimental result shows that design of the car is reasonable. The design of the car provides guidance significance for the carbon-free car.

Abstract: Abstract. Besides different field-weakening control algorithm during accelerating and decelerating process of permanent magnet synchronous motor, the control system proposed in this paper also combined Maximum torque/ampere control with field-weakening control methods. It not only satisfied the large torque and wide speed range requirement which was put on drive system by vehicle, but also improved the reliability of drive system. Modeling and simulation work of the drive system are also done with MATLAB, simulation results proved that the control system proposed in this paper is effective.

Abstract: With the finite elements analysis and topological optimization algorithm, the head structure of four-wheel independent drive pure electric vehicle is regarded as optimization objective. The vehicle’s head structure is optimized by LS-DYNA and LS-TASC on the condition that whether considering the compatibility constraint. The mass fraction curve, the mass distribution convergence curve and optimization results are used to analyze the influence of vehicle structure when considering crash compatibility, and verify that good crash compatibility means homogeneous geometric structure and homogeneous impact force in contact surface.