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The blasting quality and the rock volume blasted directly affect the cost of mines. A small charge-forward blast crater experiment was conducted to study the relationships between the rock volume blasted, the explosive unit consumption, the bulk yield, and the depth ratio. The results showed that the rational resistant line or explosive charge depth should be 0.86 times the optimal resistant line. Based on theoretical analysis of the large spacing of the holes and the small resistance line, the uniform design method was used to conduct the lateral blasting crater tests. The relationship equations among the blasting parameters, the blasting volume, and the bulk yield were obtained by regression analysis. The results illustrated that the rock volume blasted was negatively correlated with the bulk yield. The contribution rates of the resistance lines and the spacing of the holes to the blasting volume regression were 32.4% and 13.9%, respectively, and to the bulk yield regression were 65.0% and 0.256%. The impact of the resistance line on the blasting volume and the bulk yield was more significant than that of the spacing of the holes. The blasting effect of the rectangular blast hole arrangement was better than that of the square pattern. The blasting technology of large hole spacing and a small resistance line could achieve a better blasting effect while ensuring a higher rock volume blasted. The economical and reasonable blasting parameters were determined as the hole spacing of a=8.5 m and the resistance line width of W=5.5 m, with the rock volume blasted of 413.1 m3 and the bulk rate of 0.218%. This method provides an effective method for optimization of the blasting parameters and has important guiding significance for efficient and economical mining. [ABSTRACT FROM AUTHOR]

Abstract: The mutual eclipse of S4 Dione by S3 Tethys (Dec 23, 2009) and mutual occultation of S3 Tethys by S4 Dione (Apr 24, 2010) were observed at Yunnan Observatory during the international campaign in 2009–2010. The aim of this paper is to calculate the astrometric data of the involved Saturnian satellites during the mutual events, using a same dynamical model as proposed by Assafin et al. (2009) for the mutual occultation and a same one as proposed by Zhang and Liu (2011) for the mutual eclipse, and taking the scattering properties of the Saturnian satellites surfaces into account. Compared with the theory TASS 1.7 (Vienne and Duriez, 1995), the O–C(x) and O–C(y) are 10.1mas, 3.4mas for the mutual eclipse S4 by S3 and 28.4mas, −1.3mas for the mutual occultation S3 by S4, and with respect to the theory by Lainey et al. (2011), the results are 1.0mas, −5.0mas and −0.2mas, 2.5mas respectively. [Copyright &y& Elsevier]

Abstract: The mechanism of embrittlement and de-embrittlement for 2.25Cr–1Mo steel was studied based on the theory of grain boundary segregation, and the idea of critical temperature of embrittlement for embrittled material was proposed according to the iso-segregation curve in this paper. There is one critical embrittlement temperature corresponding to each degree of embrittlement. When further heat treating temperature is higher than critical temperature, it is a de-embrittlement process. Otherwise, it is an embrittlement process. The model of segregation that element P segregates to intragranular from grain boundary in the de-embrittlement process was deduced based on the theory of atom diffusion. The de-embrittled test and Auger electron spectroscopy analysis were conducted for the matrix of hydrogenation reactor served for 12 years, and the theoretical calculation is consistent with the experimental results, which indicates that the further embrittlement or de-embrittlement mechanism can be explained both qualitatively and quantitatively with combination of the theory of iso-segregation curve and the de-embrittled model derived. [Copyright &y& Elsevier]

Highlights: [•] The initial hardening rate was reduced with external stress during aging. [•] Stress-aging can accelerate the precipitation of θ ′ but restrain that of Ω. [•] Prior deformation can also accelerate the precipitation of θ ′ but restrain that of Ω. [Copyright &y& Elsevier]

The creep behavior of Al–Cu–Mg–Ag alloy and its microstructural evolution during creep deformation were studied at 100–210°C with the external stress of 150–300MPa. The results show that both Ω and precipitate secondarily in the under-aged sample during the creeping process, resulting in the excellent creep-resistant property compared to the peak aged sample. The temperatures between 100 and 150°C have little affect on the creep curves of the alloy. The larger external stress led to the growth of the creep holes on the grain boundaries and the higher creep temperature led to the growth of the precipitations in the grains inner. They both result in the lower creep resistance of Al–Cu–Mg–Ag alloy. The steady creep rate increased with increasing creep temperature or external stress, which can be described by a constitutive equation with the creep deformation activation energy 102.00kJ/mol. [ABSTRACT FROM AUTHOR]

Becausethe liquid fuel market in China is growing rapidly compared to thecapacity for liquid fuel production, interest of coal-to-liquid technologyis growing for producing liquid fuel. Several processes have not yetbeen industrialized. Among these, the Fischer–Tropsch (FT)process for fuel production from coal was chosen for simulation andanalysis. We consider carbon capture and storage (CCS) technologybecause of the importance of CO2emissions in climate change.Systems with and without CCS coupling were simulated using Aspen Plussoftware. We used the simulation results to estimate costs, investmentper unit of product, net present value, internal rate of return, andthe static investment recovery period as economic indicators. Theeconomic benefits of CCS technology were estimated in terms of CO2emission reductions cost and the cost for CO2capture.We also performed a price sensitivity analysis. The results revealthat CCS coupling to indirect coal liquefaction is economically feasible.With the pressure to limit CO2emissions, CCS couplingsystems for FT fuel production are expected to be competitive. [ABSTRACT FROM AUTHOR]

In 2019 January, the appearance of asteroid 6478 Gault immediately attracted attention because this object exhibited a long and thin tail that was quite different from the usual asteroids. This unexpected morphology placed asteroid 6478 Gault into the catalogue of active asteroids. We acquired photometric and spectroscopic observations on 37 nights from 2019 January to April using several telescopes, including LOT (1 m telescope) and SLT (40 cm telescope) at Lulin Observatory, and the 2.4 m telescope at Lijiang station of Yunnan Observatory. We did not find any reliable value for the rotational period of Gault during 2.5 hr and 5 hr observations on 2019 January 26 at Lijiang station and March 25 at Lulin Observatory, respectively. We classified 6478 Gault as a Q-type asteroid using visible spectrum and photometric measurements, including colors (B − V avg = 0.764 ± 0.045, V − R avg = 0.450 ± 0.023), and relative reflectance. By using Finson–Probstein analysis, the grain size for Gault's tail 2 is larger than 20 μm. [ABSTRACT FROM AUTHOR]

In order to elucidate why the inclusion of a nonpolar desensitizing agent in polymer-bonded explosives (PBXs) affects their sensitivity and safety, the intermolecular interactions between nitroguanidine (NQ: a high-energy-density compound used as a propellant and in explosive charges) and FC=CF were investigated theoretically at the B3LYP/6-311++G(2df,2p) and M06-2X/6-311++G(2df,2p) levels of theory, focusing especially on the influence of intermolecular interactions on the strength of the trigger bond in NQ. The binding energies and mechanical properties of various β-NQ/polytetrafluoroethylene PBXs were also studied via molecular dynamics simulation. The results indicated that the weak intermolecular interactions between NQ and FC=CF have almost no effect on the strength of the trigger bond or the energy barrier to the intramolecular hydrogen-transfer isomerization of NQ, as also confirmed by an AIM (atoms in molecules) analysis. However, the mechanical properties of the β-NQ/polytetrafluoroethylene PBXs were found to be significantly different from those of pure β-NQ: the PBXs showed reduced rigidity and brittleness, greater elasticity and plasticity, and-in particular-better ductility. Thus, β-NQ-based PBXs with polytetrafluoroethylene are predicted to be less sensitive to external mechanical stimuli, leading to reduced explosive sensitivity and increased safety. [ABSTRACT FROM AUTHOR]

Globally, emissions trading scheme (ETS) as a cost-effective method to facilitate emissions abatement is raising more and more concerns. Moreover, according to the prevailing goal to reach a global agreement for climate mitigation, integrating emissions trading schemes has emerged as a prominent international cooperation option. This paper implements different scenario analysis and simulates the establishing of a conceivable multi-region integrated emissions trading scheme with China, U.S., Europe, Australia, Japan and South Korea included by utilizing a computable general equilibrium model; specifically, the economic and energy impacts on China in context of multi-region integrated ETS are explicitly investigated. Results indicate that the integration of emissions trading schemes would optimize the allocation of emissions permit and yield economic welfare gains for permits importing countries. Countries with higher abatement cost like U.S., Japan and South Korea would reduce the national GDP loss by 0.16%, 1.33% and 1.42%, respectively. Furthermore, the integration of emissions trading scheme also results in the redistribution of clean energy in participating countries. For China, joining the multi-region integrated ETS would facilitate the development of clean energy, the proportion of which climbs up by 33.7% in MR scenario compared with BAU scenario. In addition, it is worth noting that the multi-region integrated ETS would have significant impacts on the role each region plays in international trade, leading to 11% decline of net export for China in MR scenario compared with SR scenario. [ABSTRACT FROM AUTHOR]

The effects of Mg content on the mechanical properties, corrosion resistance and the microstructure of Al–Cu–Mg–Ag alloys were investigated by hardness tests, tensile tests, intergranular corrosion tests, electrochemical analysis, optical microscopy (OM) and transmission electron microscopy (TEM). With the increase of Mg content, the aging hardening process of Al–Cu–Mg–Ag alloy was accelerated, and the peak hardness and the tensile strength at room temperature both increased and then decreased slightly, due to the smaller dimension and larger fraction volume of Ω phases, whereas the high temperature tensile strength increased gradually. In addition, the increase of Mg content led to a larger corrosion current density and thus a higher corrosion rate of Al–Cu–Mg–Ag alloy. The poorest corrosion resistance of Al–Cu–Mg–Ag alloy with the highest Mg content (1.2%) may be due to the largest potential difference between the PFZ and the matrix in this alloy. The alloy with higher Mg content consumed more Cu solution atoms to form the precipitations on the grain boundaries, which results in lower potential of the PFZ correspondingly. [ABSTRACT FROM AUTHOR]

The effects of interrupted aging on the microstructure, mechanical properties and corrosion resistance of Al–Cu–Mg–Ag heat-resistant alloy were investigated by hardness tests, tensile tests, exfoliation corrosion (EXCO) tests, transmission electron microscopy (TEM) and electrochemical analysis. Results showed some phases precipitated during the interrupted aging process in Al–Cu–Mg–Ag alloy, which were called secondary precipitations. The precipitations both in the grains and the grain boundaries were refined by interrupted aging. The phases on the grain boundaries of the single-aged sample were distributed discontinuously, whereas those of the interrupted-aged sample were chain-like with a wider precipitation free zone (PFZ) on both sides of the grain boundary. The elongation of Al–Cu–Mg–Ag alloy increased by 37.7% while the tensile and yield strength slightly decreased after interrupted aging. The corrosion resistance of Al–Cu–Mg–Ag alloy was mainly determined by the PFZ with the lowest self-corrosion potential. The coarse and discontinuously distributed precipitations on the grain boundaries of the single-aged sample gave rise to larger efficient PFZ width than that of the interrupted-aged sample, which then lead to wider corrosion passageway and resulted in the better exfoliation corrosion resistance of Al–Cu–Mg–Ag alloy treated by interrupted aging. [ABSTRACT FROM AUTHOR]

The effects of aging treatment on the corrosion behavior of Al–Cu–Mg–Ag alloy were studied by means of intergranular corrosion (IGC) testing, potentiodynamic polarization combined with optical microscopy (OM) and transmission electron microscopy (TEM). Corrosion testing results suggest that, the intergranular corrosion resistance properties of Al–Cu–Mg–Ag alloy decreased with increasing aging time, which is also corroborated by the potentiodynamic polarization test results for under-aged, peak-aged and the over-aged Al–Cu–Mg–Ag alloys. TEM results reveal that precipitations on the grain boundary became coarsened and distributed discontinuously with increasing aging time; widening of precipitation free zones (PFZ) is also observed. The PFZ with the lowest self-corrosion potential is preferentially attacked, and corrosion progresses along the PFZ. The corrosion resistance of over-aged Al–Cu–Mg–Ag alloy decreased because of its wider PFZ in comparison with those in other samples. [ABSTRACT FROM AUTHOR]