Study on Blasting Technology for Open-Pit Layering of Complex Mine Adjacent to High and Steep Slope

In China, mining blasting vibration has seriously threatened the safety and stability of high and steep rock slopes. In this paper, taking the east mining area of Jianshan Phosphorus Mine as the research background, combined with field survey, field blasting test, numerical simulation and theoretical analysis, we systematically studied the adjacent high-steep rock slope and the layered blasting technology of complex ore. Based on wide hole spacing blasting numerical simulation and field tests, the use of 8 × 4 m hole network parameters, oblique line hole-by-hole initiation method, detonator delay using 35 ms between holes, 65 ms between rows and 500 ms within the holes, the rock mass rate was reduced and the drilling workload was decreased. In addition, regression analysis was carried out on a large amount of vibration test data, and the attenuation law and propagation law of blasting vibration of adjacent high and steep slopes were predicted, which provided a reference for mine production blasting. By establishing a mathematical model of cumulative damage of rock mass blasting, it shows that the depth of impact of mining blasting on the slope of Jianshan open-pit was 0–3.6m, but the blasting did not cause overall damage to the adjacent high and steep slopes. In the future, this model can be used to predict rock damage caused by subsequent blasting.

Determination of the Specific Mass Rate of Multicomponent Petroleum Products Burn-up

The specific mass burn-up rate of combustible substances (materials) in case of a fire, determines the heat release intensity, the temperature of burning, the intensity of fire development and other parameters. Like the rate of flame propagation, the mass burn-up rate depends on the physical and chemical properties of substances, their aggregate state, as well as other factors. The mass burn-up rate is used in modeling the process of fire development, assessment of the rate of heat release and the intensity of the supply of extinguishing agents to fire extinguishing installations. Currently, the values of the specific mass burn-up rate are given in various reference materials for a limited number of petroleum products. For single-component substances, the desired value can also be determined by calculation. The existing calculation formulas in theory are applicable for both simple and complex substances, and, in this case, there is a need to calculate the values of the specific heat of combustion and evaporation, the specific heat capacity of the substance. However, the process of complex hydrocarbon fuels burn-up differs significantly- it is due to the gradual burning out of individual fractions in their composition. Therefore, for complex substances the calculation should be made considering the changes in density and temperature during the process of burning. The methods for determining the specific mass rate of burnout of multicomponent petroleum products are considered, the universal nomogram and calculation formula are proposed that will allow determining the specific mass rate of burn-up, knowing the density of the petroleum product under normal conditions and its boiling point.

Star Formation in CALIFA survey perturbed galaxies. II. Star Formation Histories and Oxygen Abundances

Galaxy evolution is generally affected by tidal interactions. Firstly, in this series, we reported several effects which suggest that tidal interactions contribute to regulating star formation (SF). To confirm that so, we now compare stellar mass assembly histories and SF look-back time annular profiles between CALIFA survey tidally and non-tidally perturbed galaxies. We pair their respective star-forming regions at the closest stellar mass surface densities to reduce the influence of stellar mass. The assembly histories and annular profiles show statistically significant differences so that higher star formation rates characterize regions in tidally perturbed galaxies. These regions underwent a more intense (re)activation of SF in the last 1 Gyr. Varying shapes of the annular profiles also reflect fluctuations between suppression and (re)activation of SF. Since gas-phase abundances use to be lower in more actively than in less actively star-forming galaxies, we further explore the plausible presence of metal-poor gas inflows able to dilute such abundances. The resolved relations of oxygen (O) abundance, with stellar mass density and with total gas fraction, show slightly lower O abundances for regions in tidally perturbed galaxies. The single distributions of O abundances statistically validate that so. Moreover, from a metallicity model based on stellar feedback, the mass rate differentials (inflows−outflows) show statistically valid higher values for regions in tidally perturbed galaxies. These differentials, and the metal fractions from the population synthesis, suggest dominant gas inflows in these galaxies. This dominance, and the differences in SF through time, confirm the previously reported effects of tidal interactions on SF.

Formation of ring-like structures in flared α-discs with X-ray/FUV photoevaporation

ABSTRACT Protoplanetary discs are complex dynamical systems where several processes may lead to the formation of ring-like structures and planets. These discs are flared following a profile where the vertical scale height increases with radius. In this work, we investigate the role of this disc flaring geometry on the formation of rings and holes. We combine a flattening law change with X-ray and FUV photoevaporative winds. We have used a semi-analytical 1D viscous α approach, presenting the evolution of the disc mass and mass rate in a grid of representative systems. Our results show that changing the profile of the flared disc may favour the formation of ring-like features resembling those observed in real systems at the proper evolutionary times, with proper disc masses and accretion rate values. However, these features seem to be short-lived and further enhancements are still needed for better matching all the features seen in real systems.

The Application of X-rays for an Electrodeposition of Composite Coatings with Modified Structures and Properties

Experimental studies of the effect of X-rays on the process of electrolytic deposition of composite coatings are reviewed in this paper. Particular emphasis will be on the applications of X-rays for both the modification of a structure and the mechanical characteristics of galvanic coatings. In particular, this research investigates the Co/SiO2 coatings deposited from aqueous solutions under the effect of X-rays. The results of extensive investigations into the dispersing ability of electrolytes with SiO2 nanoparticles and a mass rate of composite coatings Co/SiO2 indicates that the method of electroplating under the effect of X-rays during the process results in the intensification of diffusion in the electrolyte volume and creates dense, uniform coatings. This research demonstrates that exposure of an electrolytic cell to X-rays during the electroplating process of Co/SiO2 results in an orienting effect on the formation of crystal grains and allows for the creation of dense, morphology uniform coatings with increased hardness and improved adhesion.

Experimental Study of the Insulating Properties of a Lightweight Material Based on Fast-Hardening Highly Resistant Foams in Relation to Vapors of Toxic Organic Fluids

To isolate the surface of toxic liquids, it is proposed to use fast-hardening highly resistant foams. To obtain fast-hardening, highly resistant foams, the process of gel and foaming is combined. For this, solutions of sodium polysilicate and gelation catalyst are mixed. To increase the stability of the foams, it is proposed to add water-soluble polymers to the gel-forming composition. It is shown that a fast-hardening foam of the composition Na2O·2.5SiO2 (9%)+NaHCO3 (9%)+6% foaming agent +0.5% carboxymethyl cellulose with thickness reduces the mass rate of benzene evaporation by more than 5 times. It retains its insulating properties for more than 5 days. It is concluded that it is advisable to use fast-hardening highly resistant foams for the elimination of emergencies with the spill of toxic liquids.

Thermal destruction of gas generated from household waste

The burning of industrial, agricultural wastes and garbage into ashes is source of significant air pollution due to the following gas components CO, CO2, CH4, C2H4, H2O… etc. Thermodestruction remains one of the effective technologies used in the depollution of these components. This paper is devoted to the modelling of the thermodestruction in a cylindrical incinerator of gas waste produced by the combustion of garbage. Dimensionless transfer’s equations are solved using an implicit numerical scheme, Thomas and Gauss algorithms. We analyze the influence of the mass rate of the inlet smoke on the effectiveness of depollution.

An Enhanced Solar Hybrid Brayton and Rankine Cycles with Integrated Magnetohydrodynamic Conversion System for Electrical Power Generation

In many developing countries,the use of conventional power plants to generate electricity is not meeting the increasing demands. Therefore, it has become important to find sustainable alternatives. In the present study, a solar hybrid combined cycle power plant consisting of a solar thermal plant, large-scale gas and steam turbines, and a magnetohydrodynamic generator has been investigated under oxy-fuel combustion. The performance analysis of this system under fuel pressure rate varying from 10 to 25 bar was conducted using Cycle Tempo software. The analysis of the gas and steam combined cycle shows that the net powers and the net efficiencies obtained ranged from 98 MWe to 134 MWe and 30.5% to 40%, respectively. In addition, the integration of the magnetohydrodynamic generator to the combined cycle led to an increase in the overall power from 169 MWe to 205 MWe. Moreover, it is seen that the fuel mass rate (2.81 kg/s) obtained in the gas turbine system under oxy-fuel combustion is significantly reduced when compared to conventional systems. The incorporation of solar energy and oxy-fuel combustion in the gas turbine system has increased the combustor inlet and outlet temperature and reduced the fuel consumption. From these observations, the solar hybrid system proposed in this study does not only generates electric power but also reduce the turbine exhaust fumes and CO2 emissions, which is a key factor in minimizing environment pollution.

Detection of an ionized gas outflow in the extreme UV-luminous star-forming galaxy BOSS-EUVLG1 at z = 2.47

BOSS-EUVLG1 is the most ultraviolet (UV) and Lyα luminous galaxy to be going through a very active starburst phase detected thus far in the Universe. It is forming stars at a rate of 955 ± 118 M⊙ yr−1. We report the detection of a broad Hα component carrying 25% of the total Hα flux. The broad Hα line traces a fast and massive ionized gas outflow characterized by a total mass, log(Mout[M⊙]), of 7.94 ± 0.15, along with an outflowing velocity (Vout) of 573 ± 151 km s−1 and an outflowing mass rate (Ṁout) of 44 ± 20 M⊙ yr−1. The presence of the outflow in BOSS-EUVLG1 is also supported by the identification of blueshifted UV absorption lines in low and high ionization states. The energy involved in the Hα outflow can be explained by the ongoing star formation, without the need for an active galactic nucleus to be included in the scenario. The derived low mass-loading factor (η = 0.05 ± 0.03) indicates that, although it is massive, this phase of the outflow cannot be relevant for the quenching of the star formation, namely, the negative feedback. In addition, only a small fraction (≤15%) of the ionized outflowing material with velocities above 372 km s−1 has the capacity to escape the gravitational potential and to enrich the surrounding circumgalactic medium at distances above several tens of kpc. The ionized phase of the outflow does not carry sufficient mass or energy to play a relevant role in the evolution of the host galaxy nor in the enrichment of the intergalactic medium. As predicted by some recent simulations, other phases of the outflow could be responsible for most of the outflow energy and mass in the form of hot X-ray emitting gas. The expected emission of the extended X-ray emitting halo associated with the outflow in BOSS-EUVLG1 and similar galaxies could be detected with the future ATHENA X-ray observatory, however, there are no methods at present that would assist in their spatial resolution.

Laboratory method of determining the rate of burnout of liquid fuel

Introduction. In accordance with the provisions GOST 12.1.044-89 (ISO 4589-84) (Fire and Explosion hazard substances and materials. Nomenclature of indicators and metods of their determination) one of the important parameters of liquid combustion are the mass rate of liquid burnout and the influence of various conditions of the combustion process on the mass burnup rate. A laboratory method for determining the mass burnout rate of a combustible liquid has been developed. Goals and objectives. The aim of the study is to develop a laboratory method for determining the mass rate of liquid burn-up, which can be used in the educational process during laboratory work and to simulate the effect of combustion conditions on the mass rate of liquid burn-up. Methods. To implement this task, we used video recording of changes in the mass of the liquid during its combustion in vessels of different diameters, followed by graphical processing of the results of experiments for calculate the burn-up rate under different combustion conditions. Results and discussion. The method was tested on the example of the combustion of acetone. An example of computer-graphical result for calculating the mass rate of acetone burn-up is given. The empirical dependents of the acetone burn-up rate on the diameter of the liquid surface area is obtained. Conclusions. A laboratory method for determining the mass rate of burnout of a flammable liquid, which can be used in the educational process during laboratory work, has been developed. In contrast to GOST 12.1.044-89 (ISO 4589-84), the developed method can use vessels with a liquid diameter of more than 60 mm. Keywords: burnout rate, acetone, laboratory technique