Experimental and computational study on the separation performance of an electrostatic precipitator with curved transvers collecting plates

Aiming at the problems of low collection efficiency of fine particulate matter and large area occupied by existing electrostatic precipitators (ESP), a new type of horizontal electrode ESP is proposed. It has the advantages of accelerating turbulent coalescence, increasing the effective dust collecting area and increasing the particle driving speed. The performance of the new type of ESP is systematic studied through simulation and experiment at the same time, and the results matches well. By comparing the dust removal effect of the horizontal electrode ESP and the conventional ESP, it can be concluded that the horizontal electrode ESP has a better dust removal efficiency, and can still maintain a better dust removal effect under high air velocity. The dust removal efficiency of new ESP can reach above 98% under the experimental conditions.     

Surface controlled synthesis of Cu2FeSnS4 particles for enhanced hydrogen evolution reaction

Cu₂FeSnS₄ (CFTS) particles are synthesized using different surfactants such as thioglycolic acid (TGA), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA) via the solution process. The effect of surfactants on crystal structure, morphology, elemental composition, and electrocatalytic properties of CFTS particles are investigated. CFTS particles with a better crystalline phase are obtained in PVP (surfactant), while impurity phases are observed in TGA and PVA (surfactants). The morphology of CFTS is significantly changed when a different surfactant is used in the synthesis process. The mixture of aggregate and porous (1 μm) particles is observed when PVA is used as a surfactant to synthesize CFTS particles. At the same time, highly porous particles having nanosheets and nanoparticles at the surface are obtained in the case of PVP. In the TGA case, spherical particles with 1 μm size are observed. The electrocatalytic ability of all CFTS particles toward hydrogen evolution reactions (HER) is studied in 0.5 M H₂SO₄ electrolyte. The overpotential of PVP-based CFTS particles is the lowest as ƞ = 421 mV at 10 mA/cm² compared to the other two samples. CFTS particles synthesized using PVP exhibit enhanced electro-catalytic performance due to higher surface area.     

Effect of microwave power irradiation on TiO2 nano-structures and binder free paste screen printed dye sensitized solar cells

Titanium dioxide (TiO₂) nanostructures (nanorods and nanoparticles) were prepared using a low-cost microwave irradiation method from a polyol medium of glycerol. Titanium glycerolate and TiO₂ powders were obtained in the glycerol medium for the first time with four different power densities (240?W, 480?W, 720?W, 960?W) of irradiation using a domestic microwave oven of 2.45?GHz, to understand the impact of power on morphology tuning. The structural and morphological features of the titanium glycerolate and TiO₂ powders were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Raman spectra analysis. The TiO₂ was successfully used in the fabrication of photovoltaic devices and as a proof-of-concept binder free paste was prepared and successfully employed for photo-anode using screen printing on the fluorine-doped tin oxide substrate.     

软土地区管幕群顶管施工地面沉降监测与分析

依托上海14号线桂桥路站管幕段实例工程,对管幕群顶管顶进施工过程地面沉降情况进行监测,分析群顶管施工对地面沉降的影响,在此过程中对本工程采用水土分算或合算进行讨论。根据顶进过程实际工况和监测数据,分析管幕群顶管施工影响地面的原因,提出相应控制措施。结果表明:①管幕群顶管施工引起最大地面沉降出现在始发井出加固区区域;②在本工程中采用水土合算计算正面土压力较为符合实际情况;③管幕群顶管施工过程中影响地面变形的因素主要包括前舱压力、顶进速度、洞门止水、管壁摩擦和同步注浆等方面。     

Study on downward flame spread over extruded polystyrene foam in a vertical channel: Influence of opening area

Experimental methods and theoretical analysis are employed to investigate effects of channel opening area on downward flame spread characteristics of extruded polystyrene (XPS) thermal insulation materials on building facade. The average flame height first drops and then rises as dimensionless opening area (the ratio of sidewall opening area to sidewall area, ie, S^*) increases. As S^* rises, both the average and maximum temperature of the curtain wall decrease, and the decreasing of the average temperature is linear. XPS surface temperature history can be divided into four stages, ie, inapparent rising stage (preheating), significant rising stage (melting), dropping stage (pyrolysis), and rerising stage (ignition). The preheating length first rises and then drops as S^* increases. The XPS flame spreads steadily at the early period while acceleration occurs at the later period. For different opening areas, the difference in spread distance history is not apparent in the early stage while this difference is significant in the later stage. The flame spread rate (V_f) first increases and then decreases as S^* rises. A downward flame spread model for XPS in vertical channel with openings is built. The varied trend of V_f predicted using this model corresponds to the experimental result.     

基于GF-1数据的三峡库区水体信息精细化提取

为实现江河类狭长型水体信息的精细化提取，利用GF-1卫星数据，采用支持向量机和目视解译相结合的方法对三峡库区及重庆市水体信息进行了精细化提取。使用总体分类精度、Kappa系数、错分误差、漏分误差、制图精度和用户精度等指标对库区水体信息粗提取结果进行验证分析。结果表明:4个试验区水体提取的总体分类精度均超过90%，除试验区4的Kappa系数为0.884 1以外，其余试验区均超过0.9，提取精度较高。结合目视解译的方法，在粗提取结果的基础上对各问题进行精细化处理，得到精度高、完整性好的三峡库区以及重庆市水体信息数据，可为后续该区域的精细化遥感业务开展提供有效资料。     

First principles computational studies of spontaneous reduction reaction of Eu(III) in eutectic LiCl‐KCl molten salt

Using first principles calculations, we study fundamental mechanism of spontaneous reduction reaction of Eu³⁺ to Eu²⁺ in eutectic LiCl‐KCl molten salt. We decouple the reaction Gibbs free energy into enthalpy and entropy contributions by using rigorous thermodynamic formalism. Key structural features of the solvation shell are characterized by the radial distribution function and the coordination number. Compared with Eu²⁺, the Eu³⁺ ion has a more rigid framework of the solvation shells, corroborating its stronger electrostatic interaction with neighboring ligands of Cl^? ions and a more favorable state on the aspect of enthalpy. Computations on vibrational frequency, however, pose significant contribution of vibrational entropy to the reaction Gibbs free energy for the reduction. Vibration frequency of Eu²⁺ is smaller than that of Eu³⁺, driving a more positive change of the entropy in the reduction reaction. Furthermore, an Eu²⁺ diffuses more quickly than an Eu³⁺ in the LiCl‐KCl molten salt with switching mechanism of ligand Cl^? ions in the solvation shell. Our results propose that the spontaneity of the reduction reaction is driven by the entropic contribution by overcoming the penalty of the reaction enthalpy.     

A novel hybridized metaheuristic technique in enhancing the diagnosis of cross-sectional dent damaged offshore platform members

Offshore jacket platforms are widely used for oil and gas extraction as well as transportation in shallow to moderate water depth. Tubular cross-sectional elements are used to construct offshore platforms. Tubular cross sections impart higher resistance against hydrodynamic forces and have high torsional rigidity. During operation, the members can be partially or fully damaged due to lateral impacts. The lateral impacts can be due to ship collisions or through the impact of falling objects. The impact forces can weaken some members that influence the overall performance of the platform. This demonstrates an urgent need to develop a framework that can accurately forecast dent depth as well as dent angle of the affected members. This study investigates the use of an adaptive metaheuristics algorithm to provide automatic detection of denting damage in an offshore structure. The damage information includes dent depth and the dent angle. A model is developed in combination with the percentage of the dent depth of the damaged member and is used to assess the performance of the method. It demonstrates that small changes in stiffness of individual damaged bracing members are detectable from measurements of global structural motion.     

Crowding as an Agronomic Factor Determining the Development of Plants and the Productivity of Linseed (Linum usitatissimum L.)

ABSTRACT

Nine sowing densities of linseed were compared in a two-year experiment. Self-regulation of the density of a linseed stand resulted in a differentiated branching of the plants. The number of capsules on a linseed shoot, as well as seeds in the capsule, and the number of seeds from the shoot were highly varied from year to year, and there is even a stronger differentiation in the weight of 1000 seeds. Linear relationships were noted between the mass of seeds from the linseed plant and the number of capsules. The yield of linseed was affected by both factors. An increasing sowing rate reduced the seed yield from the shoot and the plant. At lower seeding rates, the lateral shoots contributed in the seeds yield of the plant to a higher degree compared to the main ones.