Different Effects of Wet and Dry Grinding on the Activation of Iron Ore Tailings

Improving the activity of Iron Ore Tailings(IOTs)to utilize them as a mineral admixture in cement-based minerals is still challenging.In this paper,the wet grinding technology was employed to stimulate the activity of IOTs,and the traditional dry grinding method was used as a reference.The effect of wet grinding on the activation of IOTs was evaluated through ion leaching from an alkaline solution and the reactivity index.Additionally,a detailed comparison between Dry-grinding Iron Ore Tailings(DIOTs)and Wet-grinding Iron Ore Tailings(WIOTs)was made.This comparison was based on particle characteristics,crystal structures,chemical structure,and surface properties.The results showed that the particle size of IOTs reduced rapidly during wet grinding.In addition,WIOTs had a higher activity index compared to DIOTs.The storage of lattice distortions in the quartz crystal structure was also more significant during the wet grinding process than during the dry grinding process.Moreover,both prolonged dry and wet grinding could destabilize the Si-O bond and decrease the surface binding energy.

Preparation of Micro-Iron Ore Tailings by Wet-Grinding and Its Application in Sulphoaluminate Cement

Herein,micro iron ore tailings(micro-IOTs)were prepared by wet-grinding and applied to improve sulphoaluminate cement(SAC)performance.The physicochemical properties of micro-IOTs were investigated by particle size analysis,XRD,and XPS.The hydrates trait and the hydration mechanism of micro-IOTs-SAC composite were studied by XRD,TGA,MIP,and SEM.The results demonstrated that micro-IOTs with an average grain diameter of 517 nm could be obtained by wet-grinding.The setting time of SAC gradually decreased with increasing micro-IOTs content.By adding 2%micro-IOTs,the compressive strengths of SAC pastes were enhanced about 22%and 10%at 4 h and 28 d,respectively.Moreover,the addition of micro-IOTs accelerated ettringite precipitation and changed its morphology,resulting in early strength improvement of the binary system.And increased later strength by micro-IOTs was closely related to the high content of AH_(3),fine pore structure,and high hydration degree of SAC.The findings suggested one new approach to utilize iron ore tailings in cementbased materials.

Speech interaction with a rat

This paper presents the first report of a system of human's speech interaction with rats via integration of brain–machine interfaces and automatic speech recognition technologies. We propose a novel human–rat speech interaction paradigm by incorporating speech translator module, which translates human's speech commands into suitable electrical brain stimulation to steer the rat to induce expected locomotor behaviors. The preliminary results show that we can guide a rat's movement by speech commands. We further look into the future application scenarios together with forthcoming challenges facing this newly evolved cyborg intelligent system. This work will pave the way for natural interaction with animal robots.

Description of rotational properties of the superheavy nucleus ^(256,258,260)Rf by projected shell model

Band structure of the Z=104 nucleus256Rf has been a recent research focus in nuclear physics.We performed projected shell model calculations for this and some other neighboring Rf isotopes.Specifically,we studied rotational properties of these nuclei and showed that variations in dynamic moment of inertia were sensitive to single-particle structures,which may be useful information for locating the anticipated island of stability.Electromagnetic transition properties were also calculated,and measurable quantities were predicted for further experimental test.

Evolution of chemical composition of fogwater in winter in Chengdu, China

Two sampling sites representing the urban and suburban area of Chengdu, China were sampled and analyzed for selected chemicals to characterize the evolution of the chemical composition of fogwater. A trend of total organic carbon （TOC） 〉 total nitrogen （TN） 〉 total inorganic carbon （TIC） was observed for both sites. Variation of inorganic ions indicated that inorganic pollutants were not accumulated in the fog. Concentrations of n-alkanes （C11-C37） at the urban site ranged from 7.58 to 27.75 ng/mL while at the suburban site concentrations were 2.57-21.55 ng/mL. The highest concentration of n-alkanes was observed in the mature period of fog （393.12 ng/mL） which was more than ten times that in the fog formation period （27.83 ng/mL） and the fog dissipation period （14.87 ng/mL）. Concentrations of Σ15PAHs were in the range of 7.27-38.52 ng/mL at the urban site and 2.59-22.69 ng/mL at the suburban site. Contents of PAHs in the mature period of fog （27.15 ng/mL） 〉 fog dissipation period （11.59 ng/mL） 〉 fog formation period （6.42 ng/mL）. Concentrations of dicarboxylic acids （C5-C9） ranged from 10.92 to 40.78 ng/mL, with glutaric acid （C5） as the dominant dicarboxylic acid. These data provide strong indications of the accumulation of certain organic chemicals of environmental concern in fog and fog water, and provide additional insights about processes in urban and suburban air acting on organic chemicals with similar physical chemical properties.

Molecular phylogenetic relationship of Epinephelus based on sequences of mtDNA Cty b

The mtDNA Cyt b gene was sequenced partially for Variola louti of Serranidae,Epinephelinae and seven endemic species of groupers—Epinephelus awoara,E.brunneus,E.coioides,E.longispinis,E.sexfasciatus,E.spilotoceps and E.tauvina in China.The seven endemic species and other seven foreign species of groupers—E.aeneus,E.caninus,E.drummondhayi,E.haifensis,E.labriformis,E.marginatus and E.multinotatus from the GenBank were combined and analysed as ingroup,while Variola louti was used as outgroup.We compared the 420 bp sequences of Cyt b among the 15 species and constructed two types of molecular phylogenetic trees with maximum parsimony method(MP)and neighbor-joining method(NJ)respectively.The results were as follows:(1)As to the base composition of mtDNA Cyt b sequence(402 bp)of 14 species of Epinephelus,the content of(A+T)was 53.6%,higher than that of(G+C)(46.4%).The transition/transversion ratio was 4.78 with no mutation saturation.(2)The cluster relationships between E.awoara and E.sexfasciatus,E.coioides and E.tauvina,E.longispinis and E.spilotoceps were consistent with phenotypes in taxonomy.(3)In the phylogenetic tree,the species in the Atlantic Ocean were associated closely with those in the Pacific Ocean,which suggested that the Cyt b sequences of Epinephelus were highly conserved.This may be attributed to the coordinate evolution.(4)In wel1-bred mating or heredity management,mating Epinephelus of the same branch should be avoided.It is likely to be an effective way to mate the species of the Atlantic Ocean with those of the Pacific Ocean to improve the inheritance species.