Influence of coal characteristics on laser-induced plasmas

peer reviewedEight kinds of typical coal samples were chosen for studying the influence of coal characteristics on laser—induced plasmas．Element analysis and industry analysis were carried out for every sample．Experimental study on the interaction between laser and different coal samples was completed，and factors affecting laser plasma were analyzed，such as coal moisture and coal dust．The experiment result indicates that the coal samples with different coalification degrees have different plasma time—resolved spectral characteristics，all of them tend to rise at the beginning of plasma formation (< 1us)，then with the decay of plasmas emission．they tend to decrease in about 1us，while secondary ionization occurs in highly coalificated coals after 2 us．The plasma temperature differs from one kind to another，the higher the coalification degree is，the higher the plasma temperature will be

Synthesis of TiC nanotube arrays and their excellent supercapacitor performance

Nanostructured metal carbides have numerous applications in catalysis and energy storage. However, directional construction remains a significant challenge. In this work, a novel strategy for the direct synthesis of nanostructured metal carbides using nanostructured metal oxides as the precursor is developed. TiO2 nanotube arrays (TiO2 NTAs) can be successfully transformed into TiC nanotube arrays (TiC NTAs) through electro-deoxidation and carbonization reactions in a low-temperature molten salt. TiC NTAs have a highly oriented and ordered array structure, which shows the advantages of large specific surface area, direct electron transport, and good chemical stability. Here, TiC NTA electrodes and PVA-H3PO4 electrolyte gel were assembled into a flexible quasi-solid-state supercapacitor to characterize their energy storage performance. The results show that the TiC NTA electrodes exhibit a high areal capacitance of 53.3 mF cm−2, excellent cycling stability, and mechanical flexibility. Moreover, the energy densities can reach 4.6 μW h cm−2 at a power density of 78.9 μW cm−2. This work provides a new strategy for the directed synthesis of nanostructured metal carbides and demonstrates the energy storage application potential of TiC NTAs. It is expected that this work will contribute to the development of the synthesis and application of nanostructured metal carbides

Strength degradation mechanism of iron coke prepared by mixed coal and Fe2O3

Iron coke, as a new type of blast furnace burden is helpful for energy saving, emission reduction and green production of iron making. This study aims to investigate the strength degradation mechanism of iron coke prepared by mixed coal and Fe2O3 to provide a theoretical direction to improve its strength. Coking and pyrolysis experiments of mixed coal and Fe2O3 were carried out between 400 and 500 ℃ temperature. Gieseler plastometer and derivative thermogravimetric (DTG) showed that added Fe2O3 inhibited the thermoplasticity and pyrolysis process of mixed coal during coking. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) results showed that added Fe2O3 decreased the aromaticity and average stacking height, but increased the interlayer spacing of crystallite, aliphatic chain length and hydrocarbon-generating potential of mixed coal during coking. Further, gas chromatography-mass spectrometer (GCsingle bondMS) analysis suggested that the added Fe2O3 inhibited the cleavage of Calsingle bondO, Calsingle bondS, Calsingle bondN, Calsingle bondCar and Calsingle bondCal bonds, reduced the generation of ethylbenzene, o-xylene and unbranched alkanes with carbon atoms in 24–26, thus decreased the amount of fluid phase generated in coking and ultimately degraded the strength of iron coke

Quantitative analysis of atmosphere by laser—induced breakdown spectroscopy

peer reviewedIn order to investigate the feasibility of quantitative analysis with laser—induced breakdown spectroscopy， plasmas were produced by a Q—switched Nd ：YAG laser interacted with the air at atmospheric pressure，then the light of plasmas entered the monochrom eter and transferred into an electric signal，and the spectra of these plasmas in the range of 600～ 800 nm were stored and analyzed by the calibration—free mode1．Under the condition of delay time of 8 s and gating pulse of 0．4 s，the temperature of plasmas，which was in local thermal equilibrium (LTE)，was 1．62× 10 K which was obtained by means of the two—dimensional Boltzmann plane．The 20．75 oxygen content and 79．25％nitrogen content in air were detected on the assum ption that there were only oxygen and nitrogen constituents in the air．The results coincide well with the fact．The feasibility was validated by the experiment，and it built a strong basis for the further study and experiment of air pollutant monitoring

Experimental and Numerical Study on Dynamic Characteristics of Droplet Impacting on a Hot Tailings Surface

It is quite important to clearly understand the fluid dynamic process of water droplets impacting on a hot extracted titanium tailings surface for the recovery and utilization of tailings. In this research, the finite volume simulations of the droplet impingement were developed by applying the volume-of-fluid method and were validated against experimental results. Droplet-impact experiments were performed by using a high-speed camera. The effects of the Weber number, surface tension value, and contact angle on the spreading factor were quantitatively investigated, and the distributions of pressure, velocity contour, and temperature were analyzed in detail during the impact process. We found that the numerical results of the impact process and spreading factor conform to the experiments. Moreover, the surface tension, contact angle, and Weber number have important consequences for droplet dynamic characteristics. Finally, a new maximum spreading factor model that is governed by Weber numbers is proposed for the extracted titanium tailings surface based on the experimental and numerical results. These findings provide a pathway for controlling dynamic interactions of the droplets impacting on the tailings&rsquo; surfaces