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Current coal industry causes significant environmental pollution and the most air pollution deaths in the world, making the development of new eco-friendly applications one of the top priorities. Coal contains up to 50 % humic substances (HS), the majority of which is humic acid (HA). HA is well known for its beneficial properties and thus compounds extracted from coal can be used to develop new applications. To address this issue, we assessed structural composition of coal HS by measuring their spectroscopic properties. As the result, obtained spectra can be used to identify information about the molecules and thus allowing describing the composition of HS. The purpose of this study was to identify HS properties of weathered coal in regards to finding new uses for this otherwise neglected natural resource. The results show that weathered coal contains relatively high oxygen content and indicate transformations of O-containing functional groups. Weathered coal has high amount of bioactive molecules as well as condensed aromatics. The major coal forming compounds are acridine, anthracene, perylene, tetracene and naphthalene and it does not depend upon where the study site is located. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents an optimizing algorithm for speed controlled of the induction motor under sensorless. According to the Lyapunov stability theory, applying the vector analyses method, through the stator current and the rotor flux are calculated to estimate rotor speed. Corresponding to sensorless control drawbacks, a variable structure control scheme for the induction motor is proposed combined with model reference method. Simulation results show that the control plan is effectively. [Copyright &y& Elsevier]

The varied emitted color of Sr3La(PO4)3:Eu2+ phosphor was synthesized using a high temperature solid-state reaction method. The phosphor exhibits two emission bands at 418 and 500 nm corresponding to the 5d→4f transition of Eu2+ ions, which occupy two different crystallographic sites of Sr2+ in the Sr3La(PO4)3 structure. With increasing the Eu2+ doping concentration, the emission color changes the cyan into the purple, and the energy transfer takes place between Eu2+ activators. The experimental results and the analysis suggest that the energy transfer mechanism should occur due to dipole-dipole interaction with an energy-transfer critical distance of 2.56 nm. When Ce3+ ions are doped together, an efficient energy transfer from Ce3+ to Eu2+ ions exists in Sr3La(PO4)3:Ce3+, Eu2+ phosphor, the energy transfer mechanism is also d-d interaction, and the energy-transfer critical distance is 2.71 nm. [ABSTRACT FROM AUTHOR]

Abstract: A model in power market for hydro-thermal-nuclear power system has been proposed in this paper. Nuclear units, hydropower units and coal-fired power units are considered to have the renewable energy best used. The model contains two sub-models: Model1 and Model2. Model1 is used to solve the problem of allocating hydro loads and thermal loads, while Model2 is used to solve the problem of optimal power dispatch within hydro units and coal-fired units. Simulation and sensitivity analysis have been done in a case study. The results reveil that the proposed model is correct and the solution approach is effective. [Copyright &y& Elsevier]

A novel red phosphor, SrIn2O4:Eu3+, Sm3+, is synthesized by a combustion method. The 5D0 → 7F2 transition of Eu3+ is dominantly observed in the photoluminescence spectrum, leading to a red emission of the phosphor. The doped Sm3+ is found to be efficient to sensitize the emission of Eu3+ and be effective to extend and strengthen the absorption of near-UV light with wavelength of 400-405 nm, and the energy transfer from Sm3+ to Eu3+ occurs and is discussed. The effect of the molar concentration of Sm3+ on the emission intensities of the red phosphor SrIn2O4:Eu3+, Sm3+ is investigated. Moreover, the chromaticity coordinates and the emission intensities of SrIn2O4:Eu3+, Sm3+ are compared to those of the conventional red phosphor Y2O2S:Eu3+. [ABSTRACT FROM AUTHOR]

White light emission is generated by combining the blue and red emissions of Eu2+ and Mn2+, respectively, and by adding the co-doping element Ba2+ in a single host lattice of Sr2B2P2O10. The effect of Eu2+ concentration on the emission intensity of Sr2B2P2O10:Eu2+ is studied, and the emission intensity reaches a maximum at 1% Eu2+ Energy migration over Eu2+ sites occurs, resulting in concentration quenching, and the concentration quenching mechanism is d-d interaction by Dexter theory. Eu2+ exhibits a high absorption in the near-UV region, and energy transfer from Eu2+ to Mn2+ occurs in Sr2B2P2O10:Eu2+,Mn2+. When Ba2+ is introduced in Sr2B2P2O10:Eu2+,Mn2+, a green emission band appears and white light is obtained. The results indicate that Sr2B2P2O10:Eu2+,Mn2+,Ba2+ is an efficient "single host lattice phosphor" for solid-state lighting technology using a UV light emitting diode to generate white light. [ABSTRACT FROM AUTHOR]