Abstract: Bottom blown stirring technology application in EAF was studied in this paper. The basic principle of bottom blowing process was researched, the bottom blown stirring can give strong stirring effect on the molten steel bath, thus bath mixing time was shortened, decarburization and dephosphorization were improved, however over stirring would lead to liquid steel incontact with atmosphere air. Reasonable process was considered on Consteel EAF. results show that: with bottom-blown stirring technology, decarburization and dephosphorization increase significantly; oxygen and lime consumption decrease; content of FeO in final slag reduces; and heat time becomes short.
Abstract: A new method for the decomposition of low-grade refractory tantalum-niobium ores using sodium hydroxide fusion was proposed. The effects of initial mineral particle size, alkali to ore mass ratio, decomposition temperature and decomposition time on the decomposition rate of the tantalum-niobium ore were investigated. The alkali to ore mass ratio, decomposition temperature and initial mineral particle size showed significant influence on the decomposition of tantalum-niobium ore. The results show that the decomposition rates of cassiterotantalite and pyrochlore in the ore can be above 98% and 99% respectively when the initial mineral particle size is less than 75µm, the mass ratio of alkali to ore is 1:1, the decomposition temperature is 650°C and the decomposition time is 30min.
Abstract: To improve the production efficiency of converter smelting and keep stabled during refining in Panzhihua Steel, the original nozzle was optimized and industrial tests have been carried out. Results show that the optimized nozzle has a better metallurgical effect on the condition that corrosion of lining is normal, the average volume of oxygen and oxygen supply intensity were increased by 1040 m3/h and 0.27 m3/(t •min） respectively, oxygen consumption was reduced by 1.99m3/t, the blowing time was lowered by 1.06 minutes, TFe content in slag is 19.65%, which is 1.5 percentage point lower than that of the original one. So, a better dephosphorization effect was obtained and metal loss is controlled.
Abstract: The solid oxide membrane (SOM) method is an emerging technology for the environmentally friendly and energy-efficient extraction of metals direct from their respective oxides. This paper reports on the successful extraction of titanium powder direct from high-titanium slag in molten calcium chloride using the SOM method. The deoxidation process was carried out at 1000 °C and potential of 3.8 V. The current feature, phase composition evolution and morphology variation were investigated experimentally. It is found that the titanium can be successfully electrochemically extracted from high-titanium slag, the deoxidation process possesses a considerable electrolysis rate, and the current efficiency reaches ~55% in 6 h. It is shown that the SOM method is a promising alternative process for the extraction of titanium direct from titanium mineral resources.
Abstract: Zhouqu County is not only an impoverished area but also a poor environment region. Frequent occurrence of geological disasters in Zhouqu, which largely determines the quality of ecological environment, affects the regional sustainable development. In this paper, on a case study of Chengguan Town of Zhouqu, two TM images acquired in pre- (2008)and post-disaster(2010) were selected to conduct the research, using remote sensing and GIS spatial analysis techniques. The state of the ecological environment and sustainable development of the region were evaluated by using the ecological footprint methodology. The results show: Firstly, the biocapacity of built-up area and cropland are reduced by 318.50gha and 82.78gha after debris flow disaster respectively, followed by forest land, grazing ground, fishing ground and barren ground, which has played a serious impediment in economic development; Secondly, the ecological deficit reaches to -0.9245gha/per-cap before disaster, however, it reduces to -1.0691gha/per-cap after disaster. This indicates that Chengguan Town is not sustainable development, after sudden disaster, the situation of unsustainable development becomes more serious; Thirdly, it is found that debris flow and landslides are mainly not only in forest land and cropland, also areas containing many people and buildings, which shows geological disasters has played a significant impact on the socio-economic development. Finally, this article provides scientific references for the restoring of ecological environment as well as scientific disaster relief after the debris flow disaster. Therefore, strengthening management and mitigation techniques of disaster is benefit to humans and socio-economic sustainable development.
Abstract: A way of measuring the average cross-sectional void fraction for vertically rising oil pipes by using closing valves quickly and optical fiber probe has been researched. Experiments were performed in oil-gas two-phase flow and the range of the average void fraction is 0.1～0.5. The relationship between average cross-sectional void fraction of a oil-gas two-phase flow and pipe’s center void fraction in vertically rising oil pipes, for different pipe diameters and varying oil flow, is obtained. An exponential model of average void fraction is also obtained with reference to Bankoff’s variable density model. It is found that local void fraction reduces from center in radial direction and the local void fraction maximum value appears in the pipe’s center.
Abstract: Air moisture in a greenhouse is an important factor to reduce crop diseases and insect pests and to increase crop yield. When soil moisture was 60%-70% of field capacity and the irrigating quota was 15mm, this paper experimentally studies the effect of air moisture on the growth of pepper in the greenhouse. Moreover, it analyzed the incidence of crop pests diseases respectively with small tube flow, infiltration irrigation, drip irrigation and furrow irrigation. The results show that the relevance between air moisture and irrigation methods is obvious. The variety trend of air temperature and air moisture are opposite, when the air temperature in a greenhouse is controlled between 25°C and 28°C, the air moisture in a greenhouse is lower. And the air moisture in a greenhouse is the lowest with infiltration irrigation, the incidence of crop diseases and insect pests is close to that with small tube flow and 35% lower than that with furrow irrigation; and the yield (2310kg/mu) is the highest with infiltration irrigation. The yield of pepper with drip irrigation, infiltration irrigation and small tube flow are 17%、39%、34% higher than that with furrow irrigation respectively.
Abstract: We describe the use of capillary zone electrophoresis (CZE) for the determination of tertiary butylhydroquinone (TBHQ) without derivatization or purification. The influences of buffer pH and voltage on the separation of TBHQ were studied. The internal standard method was used for the quantification of TBHQ. Amperometric detection was carried out at an applied potential of 0.80 V. The detection limit of TBHQ was found to be 10-6 M. Peak intensity varied linearly with TBHQ concentration from 10-4 to 5×10-6 M. The relative standard deviation (RSD) for peak intensity and migration time was in the range of 3.58–4.36% and 0.51–0.94%, respectively. The recovery of the method in food samples is 95.36% for TBHQ. The method developed is suitable for the routine analysis of synthetic phenolic antioxidant TBHQ in samples.
Abstract: For the existing artificial immune systems applied to network intrusion detection have some shortages, an improved network intrusion detection model based on the dynamic clone selection algorithm which was put forward by Kim is proposed. The model introduces the concept of self group, which is obtained by the clustering algorithm AiNet and represents common features of normal data. The self group deals with network data before they are tested by detectors. In addition, the model adopts a design of distributed network intrusion detection, and a central server manages all the immune cells, receives vaccines and vaccinats the whole network detection hosts. Experimental results show that the number of selves and detectors are reduced, the process of affinity maturation for the detector population is speeded up, and the model achieves higher detection rate and lower false positive rate with the evolution generation increases.
Abstract: Response surface methodology (RSM) complemented with a central composite design (CCD) was employed to optimize and compare three different anthocyanins extraction methods (solid–liquid extraction(SLE), ultrasonic-assisted extraction (UAE) and microwave-assisted extraction (MAE)) from blackcurrant fruits. The aim was to obtain extracts with high anthocyanins content, which would be potentially interesting for commercial applications as natural colorants. Three major independent variables such as extraction time(min), ethanol concentration (%,v/v), solution to solid ratio (mL/g) were coded at five levels and their actual values were selected on the basis of preliminary experimental results. Results indicated that the yields of anthocyanins varied when extracted with different method, the order of anthocyanins yield from high to low was: MAE (95.77%), UAE (93.65%) and SLE (90.82%). Among three reaction parameters, ethanol concentration consistently tended to significantly affect the anthocyanins yield for above three models (p < 0.0001). MAE was the best of three methods in this study and the optimal values were as follows: extract time controlled at 6.3 min, ethanol concentration maintained at 72.8%, solution to solid ratio equaled to 8.1:1 and working power at 400W. The experimental anthocyanins value under above optimum conditions could reach to 95.77±1.05% that was in perfect agreement with the predicted model 95.52%.