Influence of Hole Arrangement on the Section of Cavity Formed by Cutting Blast

In order to optimize the arrangement of cutting holes in tunnel blast in Dahongshan Copper Mine, theoretical analysis and numerical simulation were combined to preliminarily determine the diameter of the hollow hole and the distance between the charge hole and the hollow hole during cut blast, which was verified through the field blast test. The research results show that with the increase of the hole diameter, the peak compressive stress of rock surrounding the empty hole gradually decreases, and the peak tensile stress gradually increases, which is consistent with the calculation results; when the hole diameter is 10 cm, the two first blast holes are arranged horizontally and 30 cm from the empty hole, two second blast holes are arranged vertically and 40 cm away from the empty hole, and the four third blast holes are arranged at a horizontal distance of 45 cm and a vertical distance of 45 cm from the empty hole; the contour area in numerical simulation is the maximum. The difference in contour area, contour width, and contour and contour height between the measured value and the simulation result is 5.3%, 3.3%, and 3.4%, respectively, indicating that the combination of theoretical calculation and numerical simulation is suitable for prediction of cavity section after blast in tunnel excavation.

Solvent Effect on the Efficiency of Triphenylamine-Based Dye-Sensitized Solar Cells, Molecular Approach

In this research, dynamics, and kinetics of some metal-free organic dyes based on triphenylamine having a D-π-A type structure were investigated in the gas phase and solvent (ethanol, dichloromethane, toluene, tetrahydrofuran, chloroform, and dimethylformamide) using the quantum chemistry calculations. These structures consist of triphenylamine as the donor linked to the acceptor units of cyanoacrylic acid and benzoic acid via different π-conjugated systems. The obtained results show that TC601 dye having the ethynyl anthracene phenyl π-conjugated system has the preferred charge/hole transfer properties (ΔG inj/ ΔG reg ), which in ethanol as the solvent, the lowest values of ΔG inj and ΔG reg were evaluated. Molecular spectroscopic properties of the studied dyes reveal that H-P and F-P dyes have favorable molar absorption coefficients in all media. Also, the behaviors of the light-harvesting efficiency (LHE) and incident photon to current efficiency (IPCE) as the functions of the wavelength were analyzed, which show that the presence of solvent increases the values of IPCE and LHE for most studied dyes in comparison with the gas phase. Finally, based on different analyses, TC601 as the dye and ethanol as the solvent are proposed as the preferred candidates to be applied in the DSSCs.

Solvent effect on the efficiency of triphenylamine-based dye-sensitized solar cells, molecular approach

In this research, dynamics, and kinetics of some metal-free organic dyes based on triphenylamine having a D-π-A type structure were investigated in the gas phase and solvent (ethanol, dichloromethane, toluene, tetrahydrofuran, chloroform, and dimethylformamide) using the quantum chemistry calculations. These structures consist of triphenylamine as the donor linked to the acceptor units of cyanoacrylic acid and benzoic acid via different π-conjugated systems. The obtained results show that TC601 dye having the ethynyl anthracene phenyl -conjugated system has the preferred charge/hole transfer properties (Ginj/Greg), which in ethanol as the solvent, the lowest values of Ginj and Greg were evaluated. Molecular spectroscopic properties of the studied dyes reveal that H-P and F-P dyes have favorable molar absorption coefficients in all media. Also, the behaviors of the light-harvesting efficiency (LHE) and incident photon to current efficiency (IPCE) as the functions of the wavelength were analyzed, which show that the presence of solvent increases the values of IPCE and LHE for most studied dyes in comparison with the gas phase. Finally, based on different analyses, TC601 as the dye and ethanol as the solvent are proposed as the preferred candidates to be applied in the DSSCs.

Investigation of Burn Cut Parameters and Model for One-Step Raise Excavation Based on Damage Evolution Mechanisms

One-step raise excavation with burn cut is a kind of technology which use the drilling and blasting method to excavate the raise quickly. Due to the limitation of the free surface in burn cut, determination of cut parameters such as the length of burden and diameters of empty hole and charge hole is important to achieve a good effect of cut blasting. Meanwhile, the choice of the cut model is also crucial to form a proper opening. In this study, a modified Holmquist-Johnson-Cook (HJC) model, in which the tension-compression damage model and tension-compression strain rate effect model are considered, is embedded in the LS-DYNA software to investigate the damage evolution of rock in cut blasting. A simplified numerical model of burn cut is built in the LS-DYNA. The numerical results indicate that there is a threshold value of the burden length to maximize the opening. The empty hole has the effect of transferring blasting energy, and the effect becomes more obvious with the increase of the hole size. Moreover, the linear charge density of the prime cut hole can affect the compression and tension damage. Further, the comparison among four typical burn cut models are conducted based on numerical results. It demonstrates that triangular prism cut and doliform cut, which have more empty holes arrangement surrounding the prime cut hole, are better than spiral cut and diamond cut that with less empty holes locating one side of the prime cut hole in terms of energy efficiency and damage zone control.

Enhanced Photocatalytic Activation of Methane C-H Bond by Incorporate Cerium into ETS-10

<p>Ce-ETS-10 was prepared and their ability on photocatalysis coupling of methane has been studied in detail. Ce modification enhanced the photocatalysis performance of ETS-10 on methane conversion reaction, and the methane conversion can be carried out under irradiation of visible light. To study the various rare earth modification to ETS-10, various rare earth elements were introduced to ETS-10 molecular sieve, and the relative photocatalytic methane conversion performance were studied. Various characterizations were applied to examine rare earth modification behavior. The SPS results show that the Cerium modification induce visible light photovoltage, which means the strong electron-hole separation which enhance the photocatalytic performance. The charge-hole separation is non-traditional n-n heterojunction for the charge-hole separation is highly oriented and efficient at atomic scale. This mechanism shows significant enhancement for methane conversion reaction. </p>

Enhanced Photocatalytic Activation of Methane C-H Bond by Incorporate Cerium into ETS-10

<p>Ce-ETS-10 was prepared and their ability on photocatalysis coupling of methane has been studied in detail. Ce modification enhanced the photocatalysis performance of ETS-10 on methane conversion reaction, and the methane conversion can be carried out under irradiation of visible light. To study the various rare earth modification to ETS-10, various rare earth elements were introduced to ETS-10 molecular sieve, and the relative photocatalytic methane conversion performance were studied. Various characterizations were applied to examine rare earth modification behavior. The SPS results show that the Cerium modification induce visible light photovoltage, which means the strong electron-hole separation which enhance the photocatalytic performance. The charge-hole separation is non-traditional n-n heterojunction for the charge-hole separation is highly oriented and efficient at atomic scale. This mechanism shows significant enhancement for methane conversion reaction. </p>

Influence of Charge Hole Spacing on the Crack Propagation Behavior under the Effect of Empty-Hole Directional Blasting

In order to explore the reasonable spacing of charge holes in empty-hole directional blasting, based on the action mechanism of empty-hole directional blasting, the influence of charge hole spacing on crack propagation is studied, the calculation formula of charge hole spacing is deduced, and the blasting excavation process in Shijiazhuang South Ring Expressway Tunnel is simulated by finite element software. The results show that by setting empty holes on both sides of the charge holes in the peripheral blasting, the guiding cracks can be formed in the connecting direction between the empty hole and the charge hole, the propagation of cracks in other directions can be suppressed, and the spacing of charge holes can be enlarged. Reasonable charge hole spacing is very important to realize the effect of empty-hole directional blasting; the spacing is small, the rock will be overbroken, and the utilization ratio of explosives is reduced; large spacing, the guiding effect of empty holes is weak, and the effective directional cracks cannot be formed. The spacing between charge holes is closely related to the mechanical properties of rock, detonation parameters of explosive, and aperture of the charge hole and empty hole. According to the simulation results of crack propagation in different spacing, the blasting performance is the best when the charge hole spacing is 800–1000 mm, which is completely consistent with the theoretical calculation result of charge hole spacing 948 mm.

Assessment of Blast-Induced Ground Vibration Frequency in Opencast Coal Mine: a Multivariate Statistical Regression Model

The blasting is a useful technique to explore and extract the mineral resources. It gives desired output with several negative impacts in surrounding mining areas. The ground vibration is one of the most concern phenomena produced by blasting. The peak particle velocity and frequency assess the seismic hazard, risk, and the human discomfort. Frequency plays a key role to define the damage criteria limits and human discomfort. The frequency of blast-induced ground vibration depends mainly on amount of explosive, characteristic properties of rock mass and distance etc. A total number of 32 datasets have been recorded in the form of velocity components and corresponding frequencies such as; Radial, Vertical, and Transverse at an opencast mine ‘A’ located in Chhattisgarh. The Indian Standard developed the safe level of peak particle velocity at frequency range (<8Hz, 8Hz - 25Hz, >25Hz) for the various types of structures close to mine. An attempt has been made to establish the relationship among parameters such as; burden, spacing, stemming, charge, hole depth, hole diameters and distance, etc. by multivariate statistical regression analysis (MVSRA) for the prediction of ground vibration frequency. The Coefficient of Determinate (CoD) between measured and predicted frequencies has also been studied.

The Dynamics of Hole Transfer in DNA

High-energy radiation and oxidizing agents can ionize DNA. One electron oxidation gives rise to a radical cation whose charge (hole) can migrate through DNA covering several hundreds of Å, eventually leading to irreversible oxidative damage and consequent disease. Understanding the thermodynamic, kinetic and chemical aspects of the hole transport in DNA is important not only for its biological consequences, but also for assessing the properties of DNA in redox sensing or labeling. Furthermore, due to hole migration, DNA could potentially play an important role in nanoelectronics, by acting as both a template and active component. Herein, we review our work on the dynamics of hole transfer in DNA carried out in the last decade. After retrieving the thermodynamic parameters needed to address the dynamics of hole transfer by voltammetric and spectroscopic experiments and quantum chemical computations, we develop a theoretical methodology which allows for a faithful interpretation of the kinetics of the hole transport in DNA and is also capable of taking into account sequence-specific effects.

The Effect of Cu and Ga Doped ZnIn2S4 under Visible Light on the High Generation of H2 Production

A Cu+ and Ga3+ co-doped ZnIn2S4 photocatalyst (Zn(1−2x)(CuGa)xIn2S4) with controlled band gap was prepared via a simple one-step solvothermal method. Zn(1−2x)(CuGa)xIn2S4 acted as an efficient photocatalyst for H2 evolution under visible light irradiation (λ > 420 nm; 4500 µW/cm2). The effects of the (Cu and Ga)/Zn molar ratios of Zn(1−2x)(CuGa)xIn2S4 on the crystal structure (hexagonal structure), morphology (microsphere-like flower), optical property (light harvesting activity and charge hole separation ability), and photocatalytic activity have been investigated in detail. The maximum H2 evolution rate (1650 µmol·h−1·g−1) was achieved over Zn0.84(CuGa)0.13In2S4, showing a 3.3 times higher rate than that of untreated ZnIn2S4. The bandgap energy of Zn(1−2x)(CuGa)xIn2S4 decreased from 2.67 to 1.90 eV as the amount of doping Cu+ and Ga3+ increased.