15,985 research outputs found
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 . 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
Stable nanoemulsions for poorly soluble curcumin: From production to digestion response in vitro
Curcumin, a polyphenol, can induce anticancer activity depending on dose. However, oral curcumin administration is limited by its low bioavailability due to aqueous insolubility and instability against physiological conditions. This study aims at formulating nanoemulsions by phase inversion temperature to enhance curcumin loading, stability, antioxidant performance, bioaccessibility, and in vitro absorption. The selection mechanisms for oil phase (coconut oil), surfactant (polyoxyl 40 hydrogenated castor oil), co-surfactant (soy phospholipid), and aqueous phase (2 % wt citrate buffer at pH 4.5) are established. The nanoemulsions show tunable mean droplet size (26–129 nm), high curcumin loading (9.53 ± 0.49 mg/mL), polydispersity 0.05). The curcumin nanoemulsions show ∼ 11 %, 24 %, and 57 % higher retention and ∼ 10 %, 12 %, and 17 % higher antioxidant activity than raw curcumin after 3-hour simulated gastric, intestinal, and physiological incubations, respectively. During in vitro digestion and absorption, the encapsulated curcumin shows higher bioaccessibility and absorption than free curcumin (P < 0.05). The samples are stable during 4-week storage at 4˚C and room temperature without preservatives. These findings suggest the potential to develop a nanoencapsulation strategy, particularly for an oral delivery system of oil-soluble drugs
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
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