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A total of 100 agricultural soil samples, collected in the Yellow River Delta, China, were analyzed for six U.S. Environmental Protection Agency priority phthalate esters (PAEs), focusing on the characteristics of PAEs contamination and potential health risks. The detection frequencies of ∑6PAEs were 100%, where the concentration ranged from 1.087 to 14.391 mg·kg−1, with a mean value of 4.149 mg·kg−1. The most abundant PAEs were di(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DnBP). The areas with higher contents of ∑6PAEs are distributed in the western and central parts of the Yellow River Delta region and around Laizhou Bay. PAEs in the Yellow River Delta agricultural soil were attributed to pollutant emissions from petrochemical industries, plasticizers or additives, fertilizers, and pesticides. The non-carcinogenic risk of human exposure to PAEs in agricultural soils is relatively low, but the non-carcinogenic risk is higher in children than in adults, and children are a sensitive group. Under the dietary route, both DEHP and ∑2PAEs (BBP, and DEHP) pose some degree of carcinogenic risk to both local adults and children. Efforts must be made to enhance the prevention and control of PAEs contamination of agricultural soils in the Yellow River Delta region to reduce the potential risk to humans. [ABSTRACT FROM AUTHOR]

Purpose: Agricultural soils are faced with increasingly prevalent polycyclic aromatic hydrocarbons (PAHs) pollution. To remediate the PAH-contaminated agricultural soils, the degradation of PAHs in aged contaminated soils by spent mushroom substrate (SMS) of Pleurotus eryngii at different rates and frequencies was analyzed. Materials and methods: P. eryngii SMS was applied in the soils at different rates (10%, 20%, 30%, 40%) and frequencies (1, 2, 4), and the soils were incubated for 60 days. The soil physicochemical properties, soil enzymatic activities, biomass of the degrading bacteria, and degradation efficiency of PAHs were analyzed. The degradation products of phenanthrene and fluoranthene were studied. Results and discussion: The degradation efficiency of 16 PAHs in soils increased with the increase in the rate and frequency of the SMS application. The highest efficiency was 48.3% when SMS was applied at a rate of 20% and a frequency of 4. The content of soil organic matter, available potassium, and alkaline nitrogen was high when 20% SMS was applied at a high frequency. The biomass of PAH-degrading bacteria and enzyme activities in soils increased when SMS was applied. The degradation efficiency of PAHs was positively correlated with the biomass of PAH-degrading bacteria and activities of most soil enzymes (r = 0.815–0.915, p < 0.05). Conclusions: Applying SMS at a high rate and frequency enhanced the degradation of PAHs in soils. The PAHs were cleaved and the ring was opened due to the P. eryngii SMS. [ABSTRACT FROM AUTHOR]

The liquid-phase flow behavior of slag in the lower zone of a blast furnace affects the furnace permeability, performance, and productivity. The effects of pulverized coal injection (PCI) on the behavior of simulated primary slag flow were investigated by quantifying the effect of key variables including Al/Si ratio [AlO (wt.%) to SiO (wt.%)] and the amount of unburnt pulverized coal (UPC) at 1500°C. Viscosity analysis demonstrated that the slag fluidity decreased as the Al/Si ratio was increased (from 0.35 to 0.50), resulting in gradual increase of the static holdup. Increasing the amount of UPC resulted in a significant increase of the static holdup. Flooding analysis was applied to determine the maximum static holdup, which was found to be 11.5%. It was inferred that the burnout rates of pulverized coal should exceed 78.6% and 83.9% in traditional and oxygen blast furnaces, respectively. [ABSTRACT FROM AUTHOR]

The top gas recycling oxygen blast furnace (TGR-OBF) is a new ironmaking process which can significantly reduce the coke ratio and emissions of carbon dioxide. To better understand the coal combustion characteristics in the TGR-OBF, a three dimensional model was developed to simulate the lance-blowpipe-tuyere-raceway of a TGR-OBF. The combustion characteristics of pulverized coal in TGR-OBF were investigated. Furthermore, the effects of oxygen concentration and temperature were also analyzed. The simulation results show that the coal burnout increased by 16.23% compared to that of the TBF. The oxygen content has an obvious effect on the burnout. At 70% oxygen content, the coal burnout is only 21.64%, with a decrease of 50.14% compared to that of TBF. Moreover, the effect of oxygen temperature is also very obvious. [ABSTRACT FROM AUTHOR]

The autoassembly system based on an automatic drilling and riveting technology is efficient for a long lifetime and high-reliability design of modern aircrafts. The automatic feeding of the rivet plays an important role in ensuring the system reliability. This paper focuses on the design of the rivet feeding tube to improve the system reliability by decreasing or even preventing the rivet jamming. The main factors that influence the rivet transport in the tube were analyzed. To avoid the rivet jamming, an analytical method was suggested to evaluate the tube's minimum bending radius, minimum interior diameter, and lowest inlet air pressure. To verify the analytical model, the finite element simulation and experiment were carried out to study the transportation process of the rivet in the tube. The result shows that the model presented in this paper can satisfactorily offer theoretical proof for the optimization of the rivet feeding tube. [ABSTRACT FROM AUTHOR]

Analyzes the welding of heat-affected zone microstructures of austempered ductile iron (ADI). Importance of welding when the ADI castings need to be produced and repaired; Procedure of the welding; Difference in the mechanical properties of weld metal with ADI base metal; Assessment of the phase transformation and characteristics of the microstructure in the weld joint.

Joining Si3N4 to Si3N4 was carried out initially with a Cu34Ni27Ti39 brazing alloy prepared by double melting under a vacuum condition. However, the strength of the joints was not as high as expected. The causes were studied. Based on the results of the analysis, a CuNiTiB brazing filler metal was designed. The Si3N4/Si3N4 joints were then brazed with this new brazing alloy in the paste form, and joints with a three-point bend strength of 338.8 MPa at room temperature were obtained. The interfacial reactions of the joint are also discussed. With the rapidly solidified foils of the brazing alloy, the bend strength of the Si3N4/Si3N4 joints under the same brazing conditions is raised to 402 MPa at room temperature. The Si3N4/Si3N4 joints brazed with this newly developed brazing alloy exhibit a rather high and steady bend strength (about 406 MPa) at 723 K. [ABSTRACT FROM AUTHOR]

The Cu-Sn-C system P/M alloys were sintered by laser. The influence of laser sintering on the properties of the laser-sintered materials was investigated. The properties, such as the density, impact toughness, hardness and wear resistance of the laser-sintered materials are desirable. A maximum impact toughness of 11.7 J/cm2 was achieved and the wear resistance of the laser-sintered materials was tremendously increased compared with conventional sintering. The green compact made from Cu-Sn-C powders, with a thickness of 10 mm, can be penetratively sintered by using a suitable processing condition. The laser sintering was characterised by a thermal cycle which was accomplished in a relatively short time, resulting in a relatively high temperature (950 °C). The curves showing temperature profiles for the top surface and bottom of the laser-sintered specimen were recorded by thermocouples. Differences in temperatures between the top surface and bottom were very small, less than 60 °C. Some intermetallics/phases such as α-Cu, Cu31Sn8(δ), Cu4Sn(ε) and Cu6Sn5(η) were most readily produced in the laser-sintered materials and their distributions were more homogeneous than conventional sintering, owing to the better flow ability of the melt caused by a relatively high sintering temperature. The behaviour of diffusion between Cu and Sn was also studied by means of simulation diffusion couple. [ABSTRACT FROM AUTHOR]