1,626 research outputs found
The numerical simulation on the regularity of dust dispersion in whole-rock mechanized excavation face with different air-draft amount
AbstractAn experimental investigation was carried out on coal dust-inertant mixture explosions. Tests of explosion severity and flammability limit were conducted by using the Siwek 20 L vessel and influences of ignition energy, coal dust calorific value, coal dust concentration and inertant composition were taken into account. The increase of inerting results with ignition energy is followed by an approximate stabilization when ignition energy exceeds 5kJ. The ignition energy region of 5-10kJ is appropriate for inerting testing, whereas ignitors with energy lower than 5kJ produce unrealistic inerting results. The inerting effectiveness of inertant increases with the reduction of coal dust calorific value. Coal dust concentrations near the stoichiometric concentration require the greatest amount of inertant to suppress explosions. As the coal dust concentration increases beyond the stoichiometric, the amount of inertant requirement is reduced. Due to the efficient decomposition and particular flame extinguishing mechanism, monoammonium phosphate represents more excellent inerting effectiveness than calcium carbonate
Controlling extreme events on complex networks
Date of Acceptance: 29/07/2014 We thank Prof. W.-X. Wang and Prof. L. Huang for helpful discussions. This work was partially supported by AFOSR under Grant No. FA9550-10-1-0083, by NSF under Grant No. CDI-1026710 and by ARO under Grant No. W911NF-14-1-0504.Peer reviewedPublisher PD
Testing Lorentz symmetry with space-based gravitational-wave detectors
Lorentz symmetry (LS), one of the most fundamental physical symmetries, has
been extensively studied in the context of quantum gravity and unification
theories. Many of these theories predict a LS violation, which could arise from
the discreteness of spacetime, or extra dimensions. Standard-model extension
(SME) is an effective field theory to describe Lorentz violation whose effects
can be explored using precision instruments such as atomic clocks and
gravitational-wave (GW) detectors. Considering the pure-gravity sector and
matter-gravity coupling sector in the SME, we studied the leading
Lorentz-violating modifications to the time delay of light and the relativistic
frequency shift of the clock in the space-based GW detectors. We found that the
six data streams from the GW mission can construct various combinations of
measurement signals, such as single-arm round-trip path, interference path,
triangular round-trip path, etc. These measurements are sensitive to the
different combinations of SME coefficients and provide novel linear
combinations of SME coefficients different from previous studies. Based on the
orbits of TianQin, LISA, and Taiji missions, we calculated the response of
Lorentz-violating effects on the combinations of the measurement signal data
streams. Our results allow us to estimate the sensitivities for SME
coefficients: for the gravity sector coefficient ,
for matter-gravity coupling coefficients
and , and
for and .Comment: 17 pages, 10 figure
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