Study of Uniform Experiment Design Method Applying to Civil Engineering

AbstractUniform design (UD) method is one of the findings of number theory. UD has widely application scopes in traditional experimental design and compound design. Some newly developed applications by our team to civil engineering are introduced. These cases include experimental design of concrete corrosion by sulfuric acid, structural damage detection, calculation of response spectrum for stochastic pedestrian loads and reliability calculation of foundation pit and compartment fire. A nonparametric regression method, alternating conditional expectation (ACE), is also introduced to analyze the datum from UD in some cases. The results show that the UD is efficient and applicable in addressing many related problems in civil engineering since it can decrease the required number of experiments remarkably for both physical experiment and numerical experiment and cut down expense, calculation work and time. Therefore, the UD can be adopted to solve similar problems in the fields of civil engineering and other

Theoretical Model and Experimental Research on Mortar Corrosion by Sulfuric Acid in Laminar Flow

Surfaces of concrete structure could suffer the corrosion of flowing sulfuric acid coming from acid rain or sewage water. This paper establishes an analytical corrosion model and carries out experimental studies to investigate the corrosion rate of mortar in laminar flow of sulfuric acid with different flow velocities. The analytical model was deduced from the relationship between Flow Boundary Layer and Concentration Boundary Layer, connected by Schmidt number, and the dissolution diffusion process of mortar. The analytical model indicates that the corrosion rate will increase with flow velocity, but the increment effect will decrease with flow velocity in an exponential relationship. Nine groups of cement mortar specimens were tested in flow-corrosion devices for 1440 hours. The corrosion rate was obtained for the cases of the water cement ratio of mortar 0.5, the pH value of sulfuric acid 3.4 and the flow velocities ranging from 0.13 m/s to 1.57 m/s

Observation of valley Landau-Zener-Bloch oscillations and pseudospin imbalance in photonic graphene

We demonstrate inter-valley Bloch oscillation (BO) and Landau-Zener tunneling (LZT) in an optically-induced honeycomb lattice with a refractive index gradient. Unlike previously observed BO in a gapped square lattice, we show non-adiabatic beam dynamics that are highly sensitive to the direction of the index gradient and the choice of the Dirac cones. In particular, a symmetry-preserving potential leads to nearly perfect LZT and coherent BO between the inequivalent valleys, whereas a symmetry-breaking potential generates asymmetric scattering, imperfect LZT, and valley-sensitive generation of vortices mediated by a pseudospin imbalance. This clearly indicates that, near the Dirac points, the transverse gradient does not always act as a simple scalar force as commonly assumed, and the LZT probability is strongly affected by the sublattice symmetry as analyzed from an effective Landau-Zener Hamiltonian. Our results illustrate the anisotropic response of an otherwise isotropic Dirac platform to real-space potentials acting as strong driving fields, which may be useful for manipulation of pseudospin and valley degrees of freedom in graphene-like systems

Vacuum-Induced Symmetry Breaking of Chiral Enantiomer Formation in Chemical Reactions

A material with symmetry breaking inside can transmit the symmetry breaking to its vicinity by vacuum electromagnetic fluctuations. Here, we show that vacuum quantum fluctuations proximate to a parity-symmetry-broken material can induce a chirality-dependent spectral shift of chiral molecules, resulting in a chemical reaction process that favors producing one chirality over the other. We calculate concrete examples and evaluate the chirality production rate with experimentally realizable parameters, showing the promise of selecting chirality with symmetry-broken vacuum quantum fluctuations.Comment: 7+10 pages, 4+1 figures. Published version. Title changed. Comments are welcom