Experimental application to a water delivery canal of a distributed MPC with stability constraints

In this work, a novel distributed MPC algorithm, denoted D-SIORHC, is applied to upstream local control of a pilot water delivery canal. The D-SIORHC algorithm is based on MPC control agents that incorporate stability constraints and communicate only with their adjacent neighbors in order to achieve a coordinated action. Experimental results that show the effect of the parameters configuring the local controllers are presented

Crustal deformation in the New Madrid seismic zone and the role of postseismic processes

Global Navigation Satellite System data across the New Madrid seismic zone (NMSZ) in the central United States over the period from 2000 through 2014 are analyzed and modeled with several deformation mechanisms including the following: (1) creep on subsurface dislocations, (2) postseismic frictional afterslip and viscoelastic relaxation from the 1811-1812 and 1450 earthquakes in the NMSZ, and (3) regional strain. In agreement with previous studies, a dislocation creeping at about 4 mm/yr between 12 and 20 km depth along the downdip extension of the Reelfoot fault reproduces the observations well. We find that a dynamic model of postseismic frictional afterslip from the 1450 and February 1812 Reelfoot fault events can explain this creep. Kinematic and dynamic models involving the Cottonwood Grove fault provide minimal predictive power. This is likely due to the smaller size of the December 1811 event on the Cottonwood Grove fault and a distribution of stations better suited to constrain localized strain across the Reelfoot fault. Regional compressive strain across the NMSZ is found to be less than 3 × 10-9/yr. If much of the present-day surface deformation results from afterslip, it is likely that many of the earthquakes we see today in the NMSZ are aftershocks from the 1811-1812 New Madrid earthquakes. Despite this conclusion, our results are consistent with observations and models of intraplate earthquake clustering. Given this and the recent paleoseismic history of the region, we suggest that seismic hazard is likely to remain significant

Electron-Transport Properties of Few-Layer Black Phosphorus

We perform the first-principles computational study of the effect of number of stacking layers and stacking style of the few-layer black phosphorus (BPs) on the electronic properties, including transport gap, current–voltage (<i>i</i>–<i>v</i>) relation, and differential conductance. Our computation is based on the nonequilibrium Green’s function approach combined with density functional theory calculations. Specifically, we compute electron-transport properties of monolayer BP, bilayer BP, and trilayer BP as well as bilayer BPs with AB-, AA-, or AC-stacking. We find that the stacking number has greater influence on the transport gap than the stacking type. Conversely, the stacking type has greater influence on <i>i</i>–<i>v</i> curve and differential conductance than on the transport gap. This study offers useful guidance for determining the number of stacking layers and the stacking style of few-layer BP sheets in future experimental measurements and for potential applications in nanoelectronic devices

The Effect of Multiple Anisotropic Scattering Pattern on S Wave Energy Density Envelope

Based on the multiple anisotropic scattering theory, we reevaluate the spherical harmonic series expansion of directional scattering coefficient. A characteristic source time is introduced to define the initial impulse width of energy density at the source. We use an analytical expression of the initial spectral energy intensity in the integral equation of seismic wave energy density at any given frequency. The modified integral equation is solved by a discrete wave number method. Based on this solution, we investigate the effect of scattering pattern on S wave energy density envelope. And the numerical simulation shows that after the S arrival time the difference of the energy density envelope between the multiple anisotropic scattering pattern and the isotropic scattering pattern increases with distances. Using forward anisotropic scattering pattern, we successfully reproduce the common decay of the seismic coda wave energy density envelopes at different hypocentral distances. For the same pattern, the S wave energy density envelope broadens with increasing hypocentral distance. Finally, we verify the forward anisotropic scattering pattern with the observation from the aftershock of the 2008 Wells, Nevada earthquake in USA

Al₂C Monolayer Sheet and Nanoribbons with Unique Direction-Dependent Acoustic-Phonon-Limited Carrier Mobility and Carrier Polarity

The intrinsic acoustic-phonon-limited carrier mobility (μ) of Al₂C monolayer sheet and nanoribbons are investigated using ab initio computation and deformation potential theory. It is found that the polarity of the room-temperature carrier mobility of the Al₂C monolayer is direction-dependent, with μ of electron (<i>e</i>) and hole (<i>h</i>) being 2348 and 40.77 cm²/V/s, respectively, in the armchair direction and 59.95 (<i>e</i>) and 705.8 (<i>h</i>) in the zigzag direction. More interestingly, one-dimensional Al₂C nanoribbons not only can retain the direction-dependent polarity but also may entail even higher mobility, in contrast to either the graphene nanoribbons which tend to exhibit lower μ compared to the two-dimensional graphene or the MoS₂ nanoribbons which have reversed polarity compared to the MoS₂ sheet. As an example, the Al-terminated zigzag nanoribbon with a width of 4.1 nm exhibits μ of 212.6 (<i>e</i>) and 2087 (<i>h</i>) cm²/V/s, while the C-terminated armchair nanoribbon with a width 2.6 nm exhibits μ of 1090 (<i>e</i>) and 673.9 (<i>h</i>) cm²/V/s; the C-terminated zigzag nanoribbon with a width 3.7 nm exhibits μ of 177.6 (<i>e</i>) and 1889 (<i>h</i>) cm²/V/s, and the Al-terminated armchair nanoribbon with a width 2.4 nm exhibits μ of 6695 (<i>e</i>) and 518.4 (<i>h</i>) cm²/V/s. The high carrier mobility, μ, coupled with polarity and direction dependence endows the Al₂C sheet and nanoribbons with unique transport properties that can be exploited for special applications in nanoelectronics