Advanced Materials Research Vols. 201-203

Abstract: a kind of multidimensional vibrating screen has been developed by the author in order to improve the screening efficiency of material. The paper introduces the structure composition and functional properties of multidimensional vibrating screen. The structural performance parameters such as degree of freedom, virtual constraint and coupling degree of the main mechanism have been calculated. And the motion performance of the multidimensional vibrating screen has been analyzed. Meanwhile the kinematics equation is established. This kind of multidimensional vibrating screen not only has concise structure and better symmetry and decoupling performance, but also improve the dispersion and leaking screen effect obviously compared with traditional vibrating screen.

Abstract: Shape distribution is considered as a kind of art state 3D model retrieval algorithm due to its simplicity, robustness, and not need model pretreatment. Its disadvantage is that the retrieval precision is not high enough. Despite the introduction of five kinds of shape functions, each of which can not sufficiently expresse the 3D models. This paper uses the D2 distribution, the improved D1 distribution and the total surface area method to retrieve 3D models respectively. Then give weights to each method after unitary them. Set fuzzy rules are set to decide the fuzzy weights of three methods according to the mean proportion and variance proportion, Experimental results show that this algorithm can improve the retrieval results significantly.

Abstract: When the production run is short and process parameters change frequently, it is difficult to monitor the process using traditional control charts. In such a case, the coefficient of variation (CV) is very useful for monitoring the process variability. The CV control chart, however, is not sensitive at small shift in the magnitude of CV. The CV-EWMA (exponentially weighted moving average) control chart which was developed recently is effective in detecting a small shifts of CV. In this paper, we propose the CV-DEWMA control chart, combining the DEWMA (double exponentially weighted moving average) technique. We show that CV-DEWMA control chart perform better than CV-EWMA control chart in detecting small shifts when sample size n is larger than 5.

Abstract: Carbochlorination of niobium in the tailings of Baogang concentrator was experimentally studied, and the activated carbon was used as the reducing agent and chlorine gas as the chlorinating agent. The effects of the reaction time and the temperature on chlorination rate of niobium in tailings were investigated. The result showed that when the tailings were chlorinated at 800 for 2 h,96.15% of niobium was yield.

Abstract: In order to profound the function of stress wave in vibration turning and present the effectiveness of instant change of stress and strain in the workpiece under the shock load,put forward a simulation model of materials obeying Prandtl-Reuss flow principle with non-linear constitutive relation for vibration turning with low frequency.Related techniques have been stressed on criterion of chip separation from the workpiece, friction between the chip and the rake of the tool. Results of simulation for both conventional and vibratory turning show that the dynamic stress intension factor is 1.45 times or more in vibratory turning than that in conventional turning. It is the stress wave that leads to the accumulation and concentration of stress, the dislocation pile-up, facilitating the chip generation and development.

Abstract: A new method for slag detection in continuous casting is discussed, which is based on eddy current effect. New system is simulated using finite element method; also experiment is done to verification the feasibility of slag detection. It is demonstrated that the new system is convenient installation and maintenance with higher resolution.

Abstract: The multi-body dynamics analysis is an important method to analyze the movement and dynamics characteristics of a car in modern vehicle design process . The twist beam rear suspension which is for rear wheel steering was widely equipped on front engine rear wheel drive vehicles . The modeling of twist beam rear suspensions is always difficult to describe accurately for its unique structural behaviour . First of all , a non-linear method based on multi-body dynamics was used to establish the dynamics model of the twist beam rear suspension system by using the ADAMS/Car . Secondly, the kinematics analysis of the rear suspension was realized and the main suspension parameters (toe angle, camber angle and wheel base) were calculated by changing wheel travel by means of ADAMS/Car . Finally , the suspension was optimized . The result shows that integrative use of ADAMS/Car and ADAMS/Insight in the kinematics analysis and optimized design of the suspensions is rapidly and effectively to design vehicle suspensions .

Abstract: In this paper, the method of microwave reduction roasting was applied to investigate the heating and weight loss process from hematite to magnetite in crude niobium concentrate under the protection of argon. The kinetics of microwave reduction roasting of hematite in crude niobium concentrate were analyzed and calculated at the temperature range of 500°C ~850°C by way of non-isothermal thermogravimetry and isothermal gravimetric analysis. Results from this investigation demonstrated that the activation energy of microwave reduction roasting calculated by non-isothermal thermogravimetry was 26.5769kJ•mol^-1, and the activation energy calculated by isothermal gravimetric analysis was 64.1203kJ•mol^-1. Compared with the method of reduction roasting under resistance heating, the activation energy of microwave reduction roasting was small, and the reaction rate was fast.

Abstract: In this experimental work, Micro Powder Injection Molding (μPIM) was carried out with stainless steel feedstock. The feedstocks with powder loading between 60 v/o to 62 v/o were prepared with 5μm stainless steel powder, Polyethelena Glycol (PEG), Polymethyl Methacrilate (PMMA) and Cellulose Acetate Butyrate (CAB). The main objective was to determine the homogeneity and flow characteristics of the mixture. Capillary rheometer method was performed to define the sensitivity of viscosity to shear rate and temperature for the mixture. The rheological properties were investigated and analyzed through relevant equations. Results show that the flow ability and characteristics of μPIM feedstocks highly depend on the mixture composition. Feedstock at 61 v/o exhibited the most suitable characteristics when mixed at temperature of 130°C with a rotor speed of 30rpm.

Abstract: Leaching behaviors of zinc, copper, indium and iron from a sphalerite concentrate in sulfuric acid-oxygen system has been investigated in the present paper. Various parameters were studied including particle size, concentration of sulfuric acid, partial pressure of oxygen, leaching temperature, and leaching time. The experimental data indicated that under the typical plant conditions employed up to 99% zinc , 85% copper and 90% indium extraction were achieved. The mineralogical analysis of the residue showed that the main minerals are elemental sulphur, unreacted pyrite and quartz, the amount of sulphide sulphur oxidized to sulfur during leaching is 81%. This process provides an effective way for the extraction of zinc, copper and indium from sphalerite concentrate.