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1

Numerical simulation of flow field in enhanced gravity concentrator

Zhu X., Tao Y., Zhang L..

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 3

975--980

EN

Enhanced gravity concentrator have excellent separation accuracy for the fine mineral particles. However, its internal flow characteristics are still in unclear. Therefore, numerical simulation was conducted to study the flow characteristics of concentrator. Effect of centrifugal force and fluidization water pressure on the velocity component of fluid was studied. The simulation accuracy was verified by the theoretical calculation. The turbulence intensity in the radial direction was analyzed to reveal the gradient characteristics. Results show that the three-dimensional velocity has different order of magnitude. The increase of centrifugal force significantly improves the three-dimensional velocity of fluid. However, the fluidization water pressure has little influence on the tangential velocity and axial velocity, but it can effectively improve the radial velocity. High turbulent flow energy and high turbulence dissipation rate are presented in the near wall region, which allows the light particles reentering the separation region. Meanwhile, the fluid presents stable flow pattern in the fall wall region that is conducive to the stratification process. In addition, the increase of centrifugal force increases the turbulence in the near wall region; however, fluidization pressure has no effect.

2

Experimental study and numerical simulation on fly ash separation with different plate voltages in rotary triboelectrostatic separator

Zhang L., Tao Y., Tao D., Zhang W., Yang L.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 3

722--731

EN

As the main solid wastes of coal-fired power plants, fly ash particles with different electrical properties are usually recycled using triboelectrostatic separator. The purpose of this study was to investigate the effect of different plate voltages on the separation of fly ash in a rotary triboelectrostatic separator with experiments and numerical simulation. The maximum values of yield of ash products (48.30%), and decarbonisation rate (50.89%) and the minimum loss-on-ignition (6.61%) were obtained when the plate voltage was 24 kV in the separation experiments, while 55.98%, 59.46%, 5.80% were reached respectively when the plate voltage was 26 kV in the simulation. In general, experimental data were similar with numerical simulation. The turning points appeared around 25 kV due to the increasing mismatch in products, which resulted from the reinforced rebound phenomena, namely the charged particle rebound from the electrode plate with a larger reflection velocity, when the plate voltage increased from 18 to 28 kV. It was validated by the numerical simulation results.

3

Flexible diamond-like carbon film prepared by hydrothermal electrochemical method

Tao Y., Yi D., Zhu B., Cao W.

Materials Science Poland

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2017

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Vol. 35, No. 3

447--453

EN

Diamond-like carbon (DLC) thin films were prepared by hydrothermal electrochemical method in one-step process. The structural characterization of these films was carried out by scanning electron microscopy (SEM), Raman spectroscopy, and infrared reflectance spectroscopy (IR). It was found that there was an increased sp2 carbon content but decreased sp3 carbon and hydrogen contents with an increase in current density. The flexibility and internal stresses of the DLC films were affected by hydrogen, sp3 amorphous carbon and ordered crystalline sp2 carbon contents. The highly flexible DLC films with high sp3 carbon and hydrogen contents were prepared at a current density of 0.001 mA/cm2.

4

Abnormal prediction of dense crowd videos by a purpose-driven lattice Boltzmann model

Xue Y., Liu P., Tao Y., Tang X.

International Journal of Applied Mathematics and Computer Science

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2017

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Vol. 27, no. 1

181--194

EN

In the field of intelligent crowd video analysis, the prediction of abnormal events in dense crowds is a well-known and challenging problem. By analysing crowd particle collisions and characteristics of individuals in a crowd to follow the general trend of motion, a purpose-driven lattice Boltzmann model (LBM) is proposed. The collision effect in the proposed method is measured according to the variation in crowd particle numbers in the image nodes; characteristics of the crowd following a general trend are incorporated by adjusting the particle directions. The model predicts dense crowd abnormal events in different intervals through iterations of simultaneous streaming and collision steps. Few initial frames of a video are needed to initialize the proposed model and no training procedure is required. Experimental results show that our purpose-driven LBM performs better than most state-of-the-art methods.

5

Study on the Origins of Textile Materials on the Basis of Analysis of Related Hard Relics from Chinese Excavations

Tao Y., Wang Q., Yu W.

Fibres & Textiles in Eastern Europe

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2017

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Vol. 25, no. 1 (121)

108--112

EN

Textile materials are widely available in nature, and the original time when humans started to use them must have been very early. However, they also easily aged, and most of the ancient ones had decomposed and disappeared thoroughly before we could find them, resulting that the remaining textile relics cannot reflect entirely the origins of textile materials. Fortunately large numbers of indirect evidence related to ancient textile materials can be found in many unearthed culture relics belonging to the Stone Age. Starting from the basic survival needs of primitive man, in this article, we analysed related hard relics from Chinese excavations made of stone, wood, bone, and so on. And based on this, the time of origin of the textile materials was further speculated upon.

PL

Materiały włókniste są stosowane od bardzo dawna. Jednakże tekstylia szybko się starzeją i większość starożytnych materiałów uległo rozkładowi całkowicie znikając zanim je odnaleziono, co powoduje błędy w datowaniu początku stosowania tekstyliów. Dużą liczbę dowodów pośrednich związanych z dawnymi tekstyliami można znaleźć w wielu odnalezionych reliktach kultury pochodzących z różnych epok, w tym epoki kamiennej. W artykule przeanalizowano artefakty pochodzące z chińskich wykopalisk wykonane z kamienia, drewna, kości, ceramiki itp. Na podstawie tychże analiz można określić, z którego okresu pochodzą tekstylia.

6

Experimental study on triboelectrostatic beneficiation of wet fly ash using Microwave Heating

Li H., Chen Y., Zhang X., Zhao Y., Tao Y., Li C., He X.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

328--341

EN

Triboelectrostatic beneficiation, as a physical method, of fly ash cannot only meet the technical requirements of fly ash application but also recycle of an unburned carbon as a useful energy source. The aim of this study was to investigate the feasibility of improving efficiency of triboelectrostatic beneficiation of wet fly ash using microwave heating. The wet fly ash with different moisture contents had an average loss-on-ignition of 12.56%. The fly ash samples were heated in a microwave oven before the experiments. The experimental conditions were electric field voltage of 40 kV and air flux ranging from 12 to 30 m3/h. The influence of the microwave heating on the wet fly ash triboelectrostatic beneficiation was discussed under the conditions of different microwave intensity and irradiation time. The results indicated that the removal rate and recycle rate of the unburned carbon showed a significant increase performance as the wet fly ash was processed by the microwave heating which was attributed to changes of moisture contents and dielectric constants caused by the microwave heating. The feasibility had been verified according to the experimental study on fly ash with different moisture contents. It can be concluded that the microwave heating process was efficiently applied for the wet fly ash triboelectrostatic beneficiation.

7

Deashing and desulphurization of fine oxidized coal by falcon concentrator and flotation

Zhu X., Tao Y., Sun Q., Man Z., Xian Y.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 2

634--646

EN

Flotation and enhanced gravity separation based on different separation principles were carried out to investigate the desulphurization and deashing efficiency of fine oxidized coal. Surface properties of fresh and oxidized coals were tested by XPS and results showed that the contents of hydrophobic functional groups decreased while the content of hydrophilic functional groups increased after oxidization. Floatability and density analysis results showed that the floatability of coal samples decreased sharply because of oxidation, however, density composition of coal sample only had slight changes. Separation results showed that yields of gravity concentrates outclassed that of flotation concentrates, meanwhile, ash contents and sulfur contents of gravity concentrates were far lower than that of flotation concentrates. Yields and ash contents increased with the collector dosage and achieved to be 17.83 and 26.94% respectively when the collector dosage was 1600 g•Mg-1. Yields and ash contents of gravity concentrates decreased with the centrifugal force and increased with the recoil water flow with similar sulfur content. Clean coal with yield of 53.86%, ash content of 9.81%, sulfur content of 1.47% and with a corresponding desulphurization efficiency of 44.53% was achieved at centrifugal force of 107 g and recoil water flow of 13.3 dm3•min-1. For fine oxidized coal, enhanced gravity separation has a significant advantage of the separation efficiency compared with flotation.

8

Effect of reaction temperature on carbon films prepared by a hydrothermal electrochemical method

Tao Y., Yi D., Zhu B.

Materials Science Poland

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2012

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Vol. 30, No. 1

17--22

EN

Carbon films were synthesized under hydrothermal electrochemical conditions using sugar as the carbon source at temperature ranging from 170 C to 180 C. The reaction temperature affects the degree of sugar decomposition, the concentration of carbon ions, supersaturation and overpotential of the solution, thereby affecting the morphology, orientation, and crystallinity of the films. The graphitic content (sp2) increases with increasing the processing temperature and vice versa. The higher the synthesizing temperature the less the amount of amorphous carbon (sp3). The graphite in thin films prepared at 170 C and 175 C shows a (101) preferred orientation, whereas those prepared at 180 C show a fairly random orientation. The mechanism of this synthesizing process seems to consist of three stages.

9

Bayesowski model wzrostu niezawodności oparty na dynamicznych parametrach rozkładu

Tao Y., Zhang Y. A., Chen X., Ming M.

Eksploatacja i Niezawodność

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2010

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nr 2

13-16

PL

W artykule przestudiowano metody analizy statystycznej na różnych etapach wzrostu niezawodności w oparciu o model monotoniczny. Zamodelowano zmiany jakim dynamiczne parametry rozkładu podlegają podczas badań. Podano bayesowskie modele wzrostu niezawodności dla licznych etapów wzrostu niezawodności. Na koniec metodę zweryfikowano w oparciu o przykład praktyczny.

EN

In this paper we study the statistical analysis methods at different stages of reliability growth based on the monotone model. The changes of dynamic distribution parameters during test are modeled. Bayesian reliability growth models for multiple stages of reliability growth are given. Finally the method is validated by a practical example.

10

Interactions of high current pulsed electron beam with phosphate laser glass

Wang C., Hao S., Shi F., Qi J., Tao Y., Wang B.

Materials Science Poland

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2007

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Vol. 25, No. 4

1101--1108

EN

Impact of electron beam bombardment on the surface of Nd3+ doped P2O5-B2O3-Al2O3-BaO laser glass was investigated. Physical properties of the bombarded glass were measured by 3D laser roughometer, microhardness tester, UV/VIS spectrometer, EDS and contact goniometer. Low beam energy had no significant impact on glass surface morphology and other properties. High beam energy increased glass surface roughness and decreased micro-hardness, UV/VIS transmittance and wetting angle. Thermal stress generated by high energy electron beam bombardment expanded the Griffith flaws and increased glass surface roughness.