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Recognition of Microseismic and Blasting Signals in Mines Based on Convolutional Neural Network and Stockwell Transform
The microseismic monitoring signals which need to be determined in mines include those caused by both rock bursts and by blasting. The blasting signals must be separated from the microseismic signals in order to extract the information needed for the correct location of the source and for determining the blast mechanism. The use of a convolutional neural network (CNN) is a viable approach to extract these blast characteristic parameters automatically and to achieve the accuracy needed in the signal recognition. The Stockwell Transform (or S-Transform) has excellent two-dimensional time-frequency characteristics and thus to obtain the microseismic signal and blasting vibration signal separately, the microseismic signal has been converted in this work into a two-dimensional image format by use of the S-Transform, following which it is recognized by using the CNN. The sample data given in this paper are used for model training, where the training sample is an image containing three RGB color channels. The training time can be decreased by means of reducing the picture size and thus reducing the number of training steps used. The optimal combination of parameters can then be obtained after continuously updating the training parameters. When the image size is 180 × 140 pixels, it has been shown that the test accuracy can reach 96.15% and that it is feasible to classify separately the blasting signal and the microseismic signal based on using the S-Transform and the CNN model architecture, where the training parameters were designed by synthesizing LeNet-5 and AlexNet
Removal of mercury (II) from aqueous solution by using rice residues
Sorption potential of rice residues for Hg(II) removal from aqueous solution was investigated. Rice husk (RH) and rice straw (RS) were selected and treated with sodium hydroxide (NaOH). The raw and modified adsorbents were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and BET surface area measurements. The effects of pH, initial ion concentration, and agitation time on the removal process were studied in batch adsorption experiments. Two simple kinetic models, which are pseudo-first-order and pseudo-second-order, were tested to investigate the adsorption mechanisms. The kinetic data fits to pseudo second order model with correlation coefficients greater than 0.99 for all adsorbents. The equilibrium data fitted well with the Langmuir compared to Freundlich isotherm models. Alkali-treated adsorbent obtained larger surface area and RH-NaOH showed highest adsorption capacity followed by RS-Pure > RH-Pure > RS-NaOH. The maximum removal efficiency obtained by RH-NaOH and RS-Pure was 42 mg/l (80%) at pH 6.5 and with 2 days contact time (for 50 mg/l initial concentration and 25 mg adsorbents)
Impurity scattering and Friedel oscillations in mono-layer black phosphorus
We study the effect of impurity scattering effect in black phosphorurene (BP)
in this work. For single impurity, we calculate impurity induced local density
of states (LDOS) in momentum space numerically based on tight-binding
Hamiltonian. In real space, we calculate LDOS and Friedel oscillation
analytically. LDOS shows strong anisotropy in BP. Many impurities in BP are
investigated using -matrix approximation when the density is low. Midgap
states appear in band gap with peaks in DOS. The peaks of midgap states are
dependent on impurity potential. For finite positive potential, the impurity
tends to bind negative charge carriers and vise versa. The infinite impurity
potential problem is related to chiral symmetry in BP
Liquid-liquid phase separation and morphology of internally mixed dicarboxylic acids/ammonium sulfate/water particles
Knowledge of the physical state and morphology of internally mixed organic/inorganic aerosol particles is still largely uncertain. To obtain more detailed information on liquid-liquid phase separation (LLPS) and morphology of the particles, we investigated complex mixtures of atmospherically relevant dicarboxylic acids containing 5, 6, and 7 carbon atoms (C5, C6 and C7) having oxygen-to-carbon atomic ratios (O:C) of 0.80, 0.67, and 0.57, respectively, mixed with ammonium sulfate (AS). With micrometer-sized particles of C5/AS/H_2O, C6/AS/H_2O and C7/AS/H_2O as model systems deposited on a hydrophobically coated substrate, laboratory experiments were conducted for various organic-to-inorganic dry mass ratios (OIR) using optical microscopy and Raman spectroscopy. When exposed to cycles of relative humidity (RH), each system showed significantly different phase transitions. While the C5/AS/H_2O particles showed no LLPS with OIR = 2:1, 1:1 and 1:4 down to 20% RH, the C6/AS/H_2O and C7/AS/H_2O particles exhibit LLPS upon drying at RH 50 to 85% and ~90%, respectively, via spinodal decomposition, growth of a second phase from the particle surface or nucleation-and-growth mechanisms depending on the OIR. This suggests that LLPS commonly occurs within the range of O:C < 0.7 in tropospheric organic/inorganic aerosols. To support the comparison and interpretation of the experimentally observed phase transitions, thermodynamic equilibrium calculations were performed with the AIOMFAC model. For the C7/AS/H_2O and C6/AS/H_2O systems, the calculated phase diagrams agree well with the observations while for the C5/AS/H_2O system LLPS is predicted by the model at RH below 60% and higher AS concentration, but was not observed in the experiments. Both core-shell structures and partially engulfed structures were observed for the investigated particles, suggesting that such morphologies might also exist in tropospheric aerosols
VISHNU hybrid model for viscous QCD matter at RHIC and LHC energies
In this proceeding, we briefly describe the viscous hydrodynamics + hadron
cascade hybrid model VISHNU for relativistic heavy ion collisions and report
the current status on extracting the QGP viscosity from elliptic flow data.Comment: 4 pages, 1 figure, the proceedings of 7th International Workshop on
Critical Point and Onset of Deconfinement, Wuhan, China, Nov. 7-11, 201
Solar-neutrino reactions on deuteron in effective field theory
The cross sections for low-energy neutrino-deuteron reactions are calculated
within heavy-baryon chiral perturbation theory employing cut-off regularization
scheme. The transition operators are derived up to
next-to-next-to-next-to-leading order in the Weinberg counting rules, while the
nuclear matrix elements are evaluated using the wave functions generated by a
high-quality phenomenological NN potential. With the adoption of the
axial-current-four-nucleon coupling constant fixed from the tritium beta decay
data, our calculation is free from unknown low-energy constants. Our results
exhibit a high degree of stability against different choices of the cutoff
parameter, a feature which indicates that, apart from radiative corrections,
the uncertainties in the calculated cross sections are less than 1 %.Comment: 12 pages, 3 figures. Error estimation of higher order corrections
detaile
Pair loading in Gamma-Ray Burst Fireball And Prompt Emission From Pair-Rich Reverse Shock
Gamma-ray bursts (GRBs) are believed to originate from ultra-relativistic
winds/fireballs to avoid the "compactness problem". However, the most energetic
photons in GRBs may still suffer from absorption leading to
electron/positron pair production in the winds/fireballs. We show here that in
a wide range of model parameters, the resulting pairs may dominate those
electrons associated with baryons. Later on, the pairs would be carried into a
reverse shock so that a shocked pair-rich fireball may produce a strong flash
at lower frequencies, i.e. in the IR band, in contrast with optical/UV emission
from a pair-poor fireball. The IR emission would show a 5/2 spectral index due
to strong self-absorption. Rapid responses to GRB triggers in the IR band would
detect such strong flashes. The future detections of many IR flashes will infer
that the rarity of prompt optical/UV emissions is in fact due to dust
obscuration in the star formation regions.Comment: 8 pages, 2 figures, ApJ accepte
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