Study on time delay estimation in boiler acoustic temperature measurement based on third correlation PHAT-β

In order to accurately measure the temperature of power plant boiler, a new algorithm of time delay was proposed based on third correlation and phase transform weighting on the basis of the research of traditional cross-correlation method and generalized cross-correlation. Small peaks can be weakened with the help of phase transform weighting and the addition of exponential coefficient β. The simulation result shows that the PHAT-β algorithm based on third correlation can accurately measure the value of time delay estimation compared with first correlation, second correlation and traditional third correlation, so as to improve the accurancy of temperature of power plant boiler

Study on the Changes in Immobilized Petroleum–Degrading Bacteria Beads in a Continuous Bioreactor Related to Physicochemical Performance, Degradation Ability, and Microbial Community

Continuous bioreactors for petroleum degradation and the effect factors of these bioreactors have rarely been mentioned in studies. In addition, indigenous bacteria living in seawater could influence the performance of continuous bioreactors with respect to petroleum degradation in practice. In this paper, a bioreactor fitted with immobilized petroleum–degrading bacteria beads was designed for further research. The results indicated that the diesel degradation rate of the bioreactor could remain above 50% over 27 days, while degradation performance decreased with bioremediation time. Intriguingly, the diameters of immobilized petroleum–degrading bacteria beads were reduced by 32.49% after 45 days remediation compared with the initial size of the immobilized petroleum–degrading bacteria beads. Change in immobilized petroleum–degrading bacteria beads was considered to correlate remarkably with reduced degradation efficiency. Therefore, this paper will be helpful for further study and improvement of bioreactors in the practical context of oil-spill accident recovery

Optimization of mechanical properties, biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy by heat treatment

Previous study has shown that Ti-3Cu alloy shows good antibacterial properties (>90% antibacterial rate), but the mechanical properties still need to be improved. In this paper, a series of heat-treatment processes were selected to adjust the microstructure in order to optimize the properties of Ti-3Cu alloy. Microstructure, mechanical properties, biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy at different conditions was systematically investigated by X-ray diffraction, optical microscope, scanning electron microscope, transmission electron microscopy, electrochemical measurements, tensile test, fatigue test and antibacterial test. Heat treatment could significantly improve the mechanical properties, corrosion resistance and antibacterial rate due to the redistribution of copper elements and precipitation of Ti2Cu phase. Solid solution treatment increased the yield strength from 400 to 740 MPa and improved the antibacterial rate from 33% to 65.2% while aging treatment enhanced the yield strength to 800–850 MPa and antibacterial rate (>91.32%). It was demonstrated that homogeneous distribution and fine Ti2Cu phase plays a very important role in mechanical properties, corrosion resistance and antibacterial properties

Synthesis, characterization, and debromination reactivity of cellulose-stabilized Pd/Fe nanoparticles for 2,2',4,4'-tretrabromodiphenyl ether

<div><p>In this study, two kinds of cellulose derivatives (polyanionic cellulose (PAC) and hydroxypropylmethyl cellulose (HPMC)) were selected as stabilizers of Pd/Fe nanoparticles (NPs) to investigate their influences on the debromination performances of 2,2',4,4'-tretrabromodiphenyl ether (BDE47). Field emission scanning electron microscope (FE-SEM) images revealed that the cellulose-stabilized Pd/Fe NPs were smaller and more uniform than the bare-Pd/Fe NPs. X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS) results suggested that cellulose coatings found on Pd/Fe NPs surfaces featured some antioxidation abilities, which followed the order of HPMC < PAC. Sedimentation tests demonstrated that the stabilizing power of PAC for Pd/Fe NPs was higher than that of HPMC. Fourier transfer infrared spectrometer (FTIR) results indicated that PAC molecules were bound to the Pd/Fe NPs surfaces by polar covalent bonds and hydrogen bonds, while HPMC molecules interacted with the nanoparticles by hydrogen bonds. Batch debromination test for BDE47 demonstrated that the catalytic debromination rate with cellulose-stabilized Pd/Fe NPs was higher than that with bare-Pd/Fe NPs during reaction period of 15 min. Overall, this study indicated that both celluloses are beneficial to forming smaller, more regular, stable and antioxidative Pd/Fe NPs, leading to higher debromination reactivity for BDE47 compared with the bare-Pd/Fe NPs. Therefore Pd/Fe NPs can be utilized as a promising remediation technology for the contaminated groundwater and soils.</p></div

Zeta (ζ) potentials of bare-Pd/Fe, HPMC-Pd/Fe, and PAC-Pd/Fe NPs as a function of solution pH.

<p>Fe concentration is 0.4 g L^-1 with Pd 0.3 wt% of Fe, HPMC and PAC are 1 g L^-1, respectively. Error bars represent the standard deviation of three samples.</p

Molecular weight, <i>pKa</i>, and degree of substitution (D.S.) of PAC and HPMC.

<p>Molecular weight, <i>pKa</i>, and degree of substitution (D.S.) of PAC and HPMC.</p

Enhanced strength and toughness of bulk ultrafine grained Cu by nacre-inspired lamellar structure

An ultrafine grained (UFG) bulk Cu with a novel nacre-inspired lamellar structure containing nano-bridges and aligned nanopores at inter-lamellar interfaces was fabricated by consolidation of a nanocrystal-attached ultrathin Cu flake powder by spark plasma sintering with a relatively lower pressure (50 MPa) followed by hot rolling. It was discovered that the bulk UFG Cu with such a novel structure has both higher strength and higher toughness (static toughness) than its counterpart with a conventional UFG structure, despite the latter has a perceived better metallurgical quality as evidenced by a lower content of pores. The formation mechanism of the nacre-inspired microstructure in bulk Cu and its correlation with strengthening and toughening mechanisms were illustrated. (C) 2020 Elsevier B.V. All rights reserved

Pseudo first order kinetics analysis of BDE47 reduction using bare and cellulose-stabilized Pd/Fe NPs.

<p>Pseudo first order kinetics analysis of BDE47 reduction using bare and cellulose-stabilized Pd/Fe NPs.</p

Sedimentation curves of bare and cellulose-stabilized Pd/Fe NPs.

<p>Fe concentration is 0.4 g L^-1 with Pd 0.3 wt% of Fe, cellulose is 1 g L^-1, respectively. Error bars represent the standard deviation of three samples.</p