Life cycle environmental and economic assessment of alumina recovery from secondary aluminum dross in China

Secondary aluminum dross is regarded as a hazardous solid waste in many countries. A coupled life cycle assessment and life cycle costing method was used to evaluate the environmental impact and economic cost of two processes for producing alumina from bauxite and secondary aluminum dross. The results showed that the total normalized midpoint value of the dross process is 32.16% lower than that of the bauxite process. The cost of producing 1 t alumina by dross process is 130.01 $, accounting for only 49.54$. These findings could be attributed to the decrease in energy and raw material consumption (i.e., steam, sodium hydroxide, electricity) and the relatively low cost of secondary aluminum dross. Adjusting raw materials for steam production and optimizing electricity structure could reduce the overall environmental impact of secondary aluminum dross recovery. Based on the forecast of environmental impact and policy adjustment in the future, inter-provincial dross transportation and southwest aluminum industry migration in China could be feasible solutions

BVRI photometry of 53 unusual asteroids

We present the results of BVRI photometry and classification of 53 unusual asteroids, including 35 near-Earth asteroids (NEAs), 6 high eccentricity/inclination asteroids, and 12 recently-identified asteroid-pair candidates. Most of these asteroids were not reportedly classified prior to this work. For the few asteroids that have been previously studied, the results are generally in rough agreement. In addition, we merge the results from several photometric/spectroscopic surveys to create a largest-ever sample with 449 spectrally classified NEAs for statistical analysis. We identify a "transition point" of the relative number of C/X-like and S-like NEAs at H~18D~1km with confidence level at ~95% or higher. We find that the C/X-like:S-like ratio for 18<=H<22 is about two times higher than that of H<18 (0.33+/-0.04 versus 0.17+/-0.02), virtually supporting the hypothesis that smaller NEAs generally have less weathered surface (therefore, less reddish appearance) caused by younger collision ages.Comment: 18 pages, 9 table

Momentum Distribution of Near-Zero-Energy Photoelectrons in the Strong-Field Tunneling Ionization in the Long Wavelength Limit

We investigate the ionization dynamics of Argon atoms irradiated by an ultrashort intense laser of a wavelength up to 3100 nm, addressing the momentum distribution of the photoelectrons with near-zero-energy. We find a surprising accumulation in the momentum distribution corresponding to meV energy and a \textquotedblleft V"-like structure at the slightly larger transverse momenta. Semiclassical simulations indicate the crucial role of the Coulomb attraction between the escaping electron and the remaining ion at extremely large distance. Tracing back classical trajectories, we find the tunneling electrons born in a certain window of the field phase and transverse velocity are responsible for the striking accumulation. Our theoretical results are consistent with recent meV-resolved high-precision measurements.Comment: 5 pages, 4 figure

Molecular cloning and functional analysis of the follicle-stimulating hormone (FSH) receptor gene promoter from the Jintang black goat

A 762 bp fragment of the 5’-flanking region of the FSHR gene from the Jintang black goat was cloned. The putative initial transcript site was the A at 681 bp and there were 7 putative cis-acting elements and 3 AT-rich regions. The sequence of the FSHR promoter from the Jintang black goat is 99.34% homology to Capra hircus, 32.38% to Gallus gallus and 38.55% to mouse. It could promote the EGFP, FSHR transcription in HEK293 cells, the fluorescence intensity was weaker than the CMV promoter, but the expressed FSHR could respond to the FSH signaling with signal intensity much higher than that at 24 h. This indicated that the FSHR promoter of the Jintang black goat is a strong promoter and may be a gene-special promoter.Key words: Follicle-stimulating hormone receptor, gene promoter, Jintang black goat, molecular cloning, functional analysis

MPEC 2020-A99: 2020 AV2

[no abstract

Arithmetic method of double-injection-electrode model for resistivity measurement through metal casing

Through-casing resistivity (TCR) measurement instruments such as Cased Hole Formation Resistivity are extensively used for the dynamic monitoring of oil reservoirs during the production phase in oil wells to evaluate the residual oil distribution. However, two shortcomings still exist in the common TCR model based on single-injection electrodes: The real value of steel-casing resistance is difficult to acquire, and the effect from mechanical tolerances of electrode scale is unpredictable. This paper proposes an innovative model based on doubleinjection electrodes. In this new model, all the required variables can be measured simultaneously; furthermore, a compensating arithmetic method is employed to obtain the real casing resistance. Self-adaptive goal-oriented hp-finite-element simulations have been performed to prove that the influence of mechanical tolerances of electrode scale can be reduced effectively. Therefore, the TCR measurement accuracy is highly improved