| 1. |
- Zhang, Wei-Wei, et al.
(author)
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Thermodynamic Assessment of the Cu-B System Supported by Key Experiment and First-Principles Calculations
- 2009
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In: Journal of Phase Equilibria and Diffusion. - : Springer Science and Business Media LLC. - 1547-7037 .- 1863-7345. ; 30:5, s. 480-486
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Journal article (peer-reviewed)abstract
- The Cu-B system was investigated via a hybrid approach of key experiment and thermodynamic modeling. Based on the critically assessed Cu-B phase diagram, seven crucial alloys were selected and prepared by arc melting the pure elements. An inductively coupled plasma-atomic emission spectrometric analysis was conducted to determine the compositions of the prepared alloys. The phase equilibria were determined by using x-ray diffraction, electron probe microanalysis, and differential thermal analysis. The temperature associated with the eutectic reaction, L double left right arrow (B) + (Cu); was measured to be 1028 +/- 2 degrees C. First-principles calculations indicate that the energy of inserting a B atom into the interstitial vacancy (Va) site of the lattice for Cu atoms is marginally lower than that of substituting for a Cu atom with a B atom. Consequently, the sublattice model (Cu)(B, Va) in which B atoms occupy the interstitial sites was employed for the fcc (Cu) phase rather than the model (Cu, B)(Va) in which B atoms substitute for Cu atoms. A thermodynamic modeling of the Cu-B system was then performed by considering the reliable literature data and the present experimental results. A good agreement between modeling and experiment was obtained.
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| 2. |
- Liang, Jiawei, et al.
(author)
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Performance and microbial communities of a novel integrated industrial-scale pulp and paper wastewater treatment plant
- 2021
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 278
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Journal article (peer-reviewed)abstract
- Ltd Paper production generates pulp and paper wastewater (PPW), and it is difficult to remove the high-level pollutants in PPW efficiently. Herein, an efficient industrial-scale pulp and paper wastewater treatment plant (PP-WWTP) that integrated physicochemical and biological processes is investigated and reported. This PP-WWTP treated 2.3 Mt of wastewater with 17,388 ± 1436 mg/L chemical oxygen demand (COD) annually. The PP-WWTP can effectively remove over 99.81% of the COD. In detail, the physical, anaerobic, aerobic and chemical steps accounted for 41.6%, 40.0%, 11.9%, and 6.5% of COD removal, respectively. The microbial communities of the bioreactors removed the pollutants efficiently and contained diverse microbes. Further metagenomic analyses of the bioreactors identified more than 90,000 genes/gene fragments encoding for carbohydrate-active enzymes (CAZys), demonstrating high lignocellulose degradation ability of the bioreactors at molecular level. The xylanase activity assay showed some lignocellulase in the bioreactors were functional. Recycling the residual heat from the PPW along with energy recovered from biological treatment of the PPW, in the form of biogas (20,000 m³/d), could generate more than 1.5 M USD benefits/y. The results of this study demonstrated that the integrated physicochemical and biological process for PPWW treatment could effectively remove pollutants while generating revenue.
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| 3. |
- Tang, Jinfeng, 1984, et al.
(author)
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Comprehensive evaluation of the effectiveness on metals recovery and decontamination from MSWI fly ash by an integrating hydrometallurgical process in Guangzhou
- 2020
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 728
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Journal article (peer-reviewed)abstract
- Municipal solid waste incineration (MSWI) fly ash generally contains substantial toxic elements which can be easily released into the environment, giving rise to serious environmental contaminations. In order to dispose of these harmful fly ashes safely and feasibly, an advanced and reliable strategy is needed. This work presented an integrated method designed for recycling of valuable copper (Cu) and zinc (Zn) through hydrochloric acid leaching and sequential extraction (using LIX 860N-I and Cyanex 572 for Cu and Zn as extractants, respectively) and clean-up of cadmium (Cd) and lead (Pb) in consequential waste effluent by adsorption with a versatile material – bundle-like hydroxyapatite (B-HAP). The method was applied in the pilot scale tests with recovery yields of 95% and 61% for Cu and Zn, respectively. Additionally, satisfied removal efficiencies of Cd and Pb (over 95% for both) were realized, reaching the acceptable emission level for Cd and Pb in China. A scenario based on the latest MSW data in 2018 in Guangzhou was assessed through the integrated pilot experiment. The evaluation demonstrates a reduction of a $ 20.8 million cost; over 48.2 k GJ of energy consumption and 5800 tons of CO2 emission can be reduced in 2018, comparing to that landfilled in hazardous waste sites, which reveals great benefits. The valuable metal recovery in combination with decontamination of toxic elements/substances as a complete and combined process gives a promising fly ash treatment strategy in future.
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| 4. |
- Tang, Jinfeng, 1984, et al.
(author)
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Optimizing critical metals recovery and correlative decontamination from MSWI fly ash: Evaluation of an integrating two-step leaching hydrometallurgical process
- 2022
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 368
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Journal article (peer-reviewed)abstract
- While municipal solid waste incineration (MSWI) fly ash is classified as hazardous waste, it can also serve as an urban mining source for numerous precious metals. Of particular interest are antimony (Sb) and zinc (Zn); the former of which is a strategic and critical metal that is being rapidly depleted, putting society at high risk for supply shortages. In this work, a two-step leaching method for recovering Sb and Zn from MSWI fly ash is proposed. Furthermore, the leaching behavior and adsorption mechanism of Sb in the MSWI fly ash waste stream were also investigated. Results from the first constant pH leaching tests (CPLT) showed that under diluted acidic condition, the maximum amount of Sb released from fly ash was ∼20%. In addition, at pH 4.0, 67% of the fly ash was dissolved, while 79.3% and 12.1% of the Zn and Sb, respectively, were recovered. After optimizing and executing a second Sb leaching procedure (6 M HCl solution at 60 °C), >80% of the Sb was recovered. Thus, the proposed two-step leaching process, consisting of extraction followed by decontamination using a magnetic HAP@CoFe2O4 adsorbent, can eliminate the Sb in fly ash effluent with a removal efficiency >95%. Moreover, this process produces less toxic products and lowers the effluent residue concentration. As such, the two-step process described herein is suggested for Sb and Zn recovery from fly ash; as it not only enables precious metal recovery, but also aids in treating secondary waste streams produced from urban mining.
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| 5. |
- Fenstermacher, M.E., et al.
(author)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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In: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Journal article (peer-reviewed)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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| 6. |
- Lu, R.S., et al.
(author)
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A ring-like accretion structure in M87 connecting its black hole and jet
- 2023
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In: Nature. - 0028-0836 .- 1476-4687. ; 616:7958, s. 686-690
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Journal article (peer-reviewed)abstract
- The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of [Formula: see text] Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects, in addition to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow.
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| 7. |
- Tang, Jinfeng, 1984, et al.
(author)
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Highly efficient recovery and clean-up of four heavy metals from MSWI fly ash by integrating leaching, selective extraction and adsorption
- 2019
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 234, s. 139-149
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Journal article (peer-reviewed)abstract
- Municipal solid waste incineration (MSWI) fly ash contains significant amounts of heavy metals (e.g., Cd, Cu, Pb and Zn) and is therefore considered to be a hazardous waste requiring proper treatment prior to its disposal. In this work, an integrated hydrometallurgical process for treatment of MSWI fly ash was evaluated. Valuable metals, e.g. Cu and Zn, were first recovered by combining leaching and extraction sequentially. In the next step, the t removal of Cd and Pb from the remaining leachate using four types of iron-based adsorbents was evaluated. The leaching was optimized with respect to pH, leaching time and liquid to solid ratio. A test done under optimal conditions gave metal releases of 100% and 80% for Cu and Zn as well as 100% and 85% for Cd and Pb, respectively. The resulting leachate was contacted with organic phases based on kerosene containing the extractants LIX860N–I for Cu extraction and Cyanex 572 for Zn extraction in two consecutive steps. Efficient extractions were achieved, thus demonstrating that the combination of leaching and extraction can be successfully used for the recovery of Cu and Zn. Adsorption of heavy metal ions on various iron based sorbents to detoxify the aqueous effluent from the extraction showed good removal efficiency (more than 95%) for both Cd and Pb. The results of this study show that the proposed integrated process is a promising tool that can be used in the strategy for metal recovery and detoxification of MSWI fly ash.
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| 8. |
- Chai, Jiali, et al.
(author)
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Insights on Titanium-based chalcogenides TiX2 (X = O, S, Se) as LIBs/SIBs anode materials
- 2023
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In: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 453
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Research review (peer-reviewed)abstract
- Ti-based chalcogenides TiX2 (X = O, S, Se) are widely used in the research of battery electrode materials due to its excellent rate performance and good chemical stability. In this paper, in order to improve the electrochemical performance of lithium-ion batteries (LIBs) and sodium ion batteries (SIBs), and further improve the application prospect of batteries, the strategies for design and preparation of LIBs/SIBs anode materials for Ti-based chalcogenides TiX2 (X = O, S, Se) are reviewed. The effects of the internal morphology modification, surface structure vacancy and composite with other material of TiX2 (X = O, S, Se) as LIBs/SIBs anode materials are analyzed in detail. On this basis, the application prospect of TiX2 (X = O, S, Se) as LIBs/SIBs anode is prospected, it is expected to fill the research of diversified applications of LIBs/SIBs anode materials.
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| 9. |
- Li, Yongqiang, et al.
(author)
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Durability study of seawater and sea-sand concrete under the combined effects of carbonation and chloride redistribution
- 2024
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In: Journal of Building Engineering. - 2352-7102. ; 89
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Journal article (peer-reviewed)abstract
- This study presents experimental and numerical investigations to comprehensively assess the impact of carbonation on the durability of chloride-blended seawater and sea-sand concrete. It reveals that carbonation leads to a reduction in pH and results in chloride redistribution along the carbonation depth. The microstructure of concrete after carbonation exhibits increased compaction, reduced porosity, and a refined pore structure. Rebar corrosion in this case is initiated by the excess of chloride ions, as proved by Raman results showing that corrosion product is composed of β-FeOOH. A mathematical model considering several affecting factors was proposed to predict the chloride redistribution in seawater and sea-sand concrete exposed to a carbonation environment, and the numerical results were fitted well with the experimental data. The initiation time for corrosion of the steel rebar is markedly shortened due to the combined effects of carbonation and chloride redistribution. It is verified that the ratio of [Cl−]/[OH−] is a key parameter in predicting corrosion initiation for chloride-blended concrete exposed to carbonation condition. The obtained results are expected to promote the resource utilization of seawater and sea-sand concrete in practical engineering.
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| 10. |
- Liu, Tang hong, et al.
(author)
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Differences in aerodynamic effects when trains with different marshalling forms and lengths enter a tunnel
- 2019
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In: Tunnelling and Underground Space Technology. - : Elsevier BV. - 0886-7798. ; 84, s. 70-81
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Journal article (peer-reviewed)abstract
- Unsteady Reynolds-averaged Navier-Stokes (URANS) simulations were performed to simulate trains with different marshalling forms and lengths entering a tunnel. Three models, including a short train, a double train and a long train, were used to analyse the influence of the train configuration on the pressure variations during a train's passage. The results of the numerical predictions were validated against existing experimental data, with which they showed good agreement. The differences in the maximum pressure peak distribution and the pressure fluctuations were analysed by means of Mach diagrams. The results show that the grouping length exerts a considerable influence on the amplitude of the pressure on the train body and that the influence of the grouping length on the pressure variation on the tunnel wall varies with the location in the tunnel. The tunnel space can be divided into three and four zones with regard to the influences on the maximum positive and negative pressure values, respectively. The different marshalling forms also influence the maximum peak values and local profiles of the pressure history curves, although this influence is much slighter than that of the train's grouping length.
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