Advanced Materials Research Vols. 347-353

Abstract: In order to reclaim magnetite from a magnetic tailing，on basis of the result of the analysis of the phases of ferrum in the magnetic tailing, this paper systematically studies the gravity dressing of magnetite from a magnetic tailing. The research result shows that by the technological process of the union of spiral chute – shaker dressing, the magnetic tailing does not need to be re-milled and can directly be dressed by spiral chute, the rough concentrate of the spiral chute is culled by shaker, the grade of the final concentrate of the shaker is 38.26%, the yield of concentrate is 3.95%, the recovery is 8.59%, gets a better economic dressing indexes

Abstract: Abstract. In order to investigate the chemical characteristics of precipitation on Tibetan Plateau, a total of 34 precipitation samples have been collected from individual precipitation events at the Shigatse Meteorological Station located in the south Tibetan Plateau in 2008. All samples were analyzed for major cations (NH4+, Na+, K+, Ca2+ and Mg2+) and anions (Cl−, NO3− and SO42−), conductivity and pH. The result showed that precipitation pH values ranged from 6.79 to 9.21 with an average value of 7.86. HCO3− and Ca2+ were the major ions detected in the samples, occupied 39% and 35% of the total ion mass, 80% of the total anion mass and 69% of the total cations mass, respectively. Factor analysis indicated that regional crustal dust, lake salt and local combustion products of residents were the main sources of the ionic compositions of precipitation of Shigatse region. Trajectory cluster analysis indicated that 97.1% of the air masses reaching Shigatse originated from the south, which passed through some pollution regions, as southeast Indian, Bangladesh.

Abstract: Slot plug is one of the most important units for bottom powder injection, and the parameters of slits on slot plug significantly influenced the direct motion of technique. In this paper, the parameters of slits such as thickness, width and length were theoretical studied and proposed a projected dimension. It was indicated that the optimal parameters of slits on slot plug using in bottom powder injection desulfurization was listed as follows, length exceeded 160~250mm, width exceeded 10mm, thickness was 0.15mm, and the slits should circular symmetric distribute on slot plug. The slot plug with parameters described above was industrial desulphurization tested in a 20t foundry ladle and feasible. Besides, the foundry ladle with the design and application of slits on slot plug used for bottom powder injection desulfurization was safety in production.

Abstract: Due to the world's energy shortage and increasing pressure on marine environmental protection, using solar and wind energy in ocean-going ships to reduce fuel consumption has become an international focus. At first this paper tests and analyzes aerodynamic characteristics of wing, and then ship model oblique towing test is conducted under different typical working conditions. Finally, the thesis analyzes the stability of ships which are equipped with additional wings in three different ocean-going cargo ships and provides security analysis basis for using sail-assist technology in ocean-going cargo vessels.

Abstract: The environmental impact of sewage sludges depends on the availability and phytotoxicity of their heavy metal. The influence of representative sludges (industrial sludge and municipal sludge) on the availability of heavy metals, and their effects on seed germination were compared. The total heavy metal concentrations were below the maximum permitted for land applied waste and the differences among them were small. The DTPA-extracted metal concentrations were significant different. The sum of all the fractions in the slugdes was close to the total metal content as determined by extraction with aqua regia. In addition, there were significant differences in the chemical forms of the heavy metals (Hg, Ni, As, Cd, Cu, Cr, Zn, Pb) by the sequential extraction system. The two different sludges also affected seed germination and root elongation in different ways. The most serious adverse effects were caused by the municipal sewage sludge extract.

Abstract: In this study, the affecting factors order of Pb2 + adsorbing Co3O4 is: the initial concentration > time> temperature> pH, under the conditions that initial concentration is 150 mg / L, 30 °C, pH value is 5.5 and oscillation of 60 min, the absorption is the best. The quasi-second order kinetics model can appropriately explain dynamic process of Nano Co3O4 adsorbing Pb2+, and the Langmuir equation can be the best explanation of isothermal adsorption processs. Through energy spectrum and infrared spectrum, it can be found that the process of Co3O4 adsorbing Pb2+ is mainly chemical absorption process. The concentration of Pb (Ⅱ) of mine wastewater reach the first class of irrigation water quality standards after the first time of adsorption treatment, and reach the first class of fishery water quality standard after the second treatment.

Abstract: In order to explore the influence factors of permeability during heap leaching of Yangla copper ore in China, falling head permeability test was applied to draw a comparison between the permeability of various samples, and then permeability evolutionary law of the sample ore from leaching heap was analyzed under different ore size or compaction degree. Finally, acid leaching experiments was carried out to reveal the influential mechanism of heap blockage on its permeability. The data show that the permeability coefficient of washed ore is 12.7 times than that of raw ore; permeability coefficient with the compaction degree 38.3% is only 3.78% of that in natural state; Chemical blockage brings about a fall of permeability coefficient by 93.5%, and earlier physical blockage leads to the decrease of it by 43.2%. Results show that much argillaceous fine particles in ore heap with high mud content can result in decreased permeability coefficient; and permeability coefficient of the samples decreases significantly with increased compaction degree. In addition, chemical blockage is the main reason for penetration deterioration.

Abstract: Considering the fact that when the cell temperature and solar insolation change rapidly, traditional variable step size(VSS) perturbation and observation(P&O) methods exist the defects that their tracking speed is relatively slow, there is small power oscillation around MPP(Maximum Power Point) and even some of them exist the situation of tracking unsuccessfully. This paper proposes a MPPT(Maximum Power Point Tracing) technology based on adaptive area algorithm. The simulation model of PV system is established by MATLAB. The simulation results show that the proposed method can track the MPP fast and accurately, and ensure the steady state characteristics of PV systems even when the climate conditions change rapidly. It effectively overcomes the defects of traditional variable step size perturbation and observation methods.

Abstract: All the parametric formulas in the discontinuous current mode of CCPS are given in this paper. Due to the leakage inductance and distributed capacitance existing in the high voltage high frequency transformer, the charging current decreases as the load voltage increase. To solve the issue, a dual-mode modulation strategy between pulse frequency and pulse width modulation is taken. Finally, a capacitor charging power supply of 100V input and 1600V output is designed. The experimental results confirm the correctness of the theoretical analysis and modulation strategy.

Abstract: This paper is about fermentation production of ethanol using sweet sorghum stalks as raw material. Content: The soluble part and insoluble part of sweet sorghum stalks are treated separately then ferment by the self-immobilized yeast after adding the nutrient salts. Results: after first squeezing of the stem, the sap is obtained. The slag is treated with acid, alkali and ultrasonic, then hydrolyzed by the Trichoderma viride L21 fermentation broth or directly by cellulase, and the total yield of reducing sugar is 73.22%. The power of ultrasonic is 60w and opens for 1s intervals 6s in total 20min to make obvious damage to fiber structure. The chemical compositions of sap are analyzed by atomic absorption spectroscopy and high performance liquid chromatographic. The response surface analysis is used to optimize the adding amount of the CO(NH2)2, MgSO4, KH2PO4, CaCl2, FeCl3 and so on. At last self-immobilized Saccharmyces cerevisiae FFCC2167 which has agglutination characteristic is used for fermentation. Ethanol production is 100.44 g • L-1, and the yield efficiency is 93.24％.