Stability of cenospheres in lightweight cement composites in terms of alkali-silica reaction

10.1016/j.cemconres.2012.02.010Cement and Concrete Research425721-72

Behavior of steel-concrete-steel sandwich structures with lightweight cement composite and novel shear connectors

10.1016/j.compstruct.2012.05.023Composite Structures94123500-350

Glueball spectrum based on a rigorous three-dimensional relativistic equation for two-gluon bound states II: calculation of the glueball spectrum

In the preceding paper, a rigorous three-dimensional relativistic equation for two-gluon bound states was derived from the QCD with massive gluons and represented in the angular momentum representation. In order to apply this equation to calculate the glueball spectrum, in this paper, the equation is recast in an equivalent three-dimensional relativistic equation satisfied by the two-gluon positive energy state amplitude. The interaction Hamiltonian in the equation is exactly derived and expressed as a perturbative series. The first term in the series describes the one-gluon exchange interaction which includes fully the retardation effect in it. This term plus the linear confining potential are chosen to be the interaction Hamiltonian and employed in the practical calculation. With the integrals containing three and four spherical Bessel functions in the QCD vertices being analytically calculated, the interaction Hamiltonian is given an explicit expression in the angular momentum representation. Numerically solving the relativistic equation with taking the contributions arising from the retardation effect and the longitudinal mode of gluon fields into account, a set of masses for the $0^{++},0^{-+},1^{++},1^{-+},2^{++}$ and $2^{-+\text{}}$ glueball states are obtained and are in fairly good agreement with the predictions given by the lattice simulatio

Homoserine and quorum-sensing acyl homoserine lactones as alternative sources of threonine:A potential role for homoserine kinase in insect-stage Trypanosoma brucei

10.1111/mmi.12853Molecular Microbiology951143-15

Nonlinear optics and saturation behavior of quantum dot samples under continuous wave driving

The nonlinear optical response of self-assembled quantum dots is relevant to the application of quantum dot based devices in nonlinear optics, all-optical switching, slow light and self-organization. Theoretical investigations are based on numerical simulations of a spatially and spectrally resolved rate equation model, which takes into account the strong coupling of the quantum dots to the carrier reservoir created by the wetting layer states. The complex dielectric susceptibility of the ground state is obtained. The saturation is shown to follow a behavior in between the one for a dominantly homogeneously and inhomogeneously broadened medium. Approaches to extract the nonlinear refractive index change by fringe shifts in a cavity or self-lensing are discussed. Experimental work on saturation characteristic of InGa/GaAs quantum dots close to the telecommunication O-band (1.24-1.28 mm) and of InAlAs/GaAlAs quantum dots at 780 nm is described and the first demonstration of the cw saturation of absorption in room temperature quantum dot samples is discussed in detail

Creep and shrinkage of ultra lightweight cement composite

Creep and shrinkage behaviour of an ultra lightweight cement composite (ULCC) up to 450 days was evaluated in comparison with those of a normal weight aggregate concrete (NWAC) and a lightweight aggregate concrete (LWAC) with similar 28-day compressive strength. The ULCC is characterized by low density < 1500 kg/m3 and high compressive strength about 60 MPa. Autogenous shrinkage increased rapidly in the ULCC at early-age and almost 95% occurred prior to the start of creep test at 28 days. Hence, majority of shrinkage of the ULCC during creep test was drying shrinkage. Total shrinkage of the ULCC during the 450-day creep test was the lowest compared to the NWAC and LWAC. However, corresponding total creep in the ULCC was the highest with high proportion attributed to basic creep (≥ ~90%) and limited drying creep. The high creep of the ULCC is likely due to its low E-modulus. Specific creep of the ULCC was similar to that of the NWAC, but more than 80% higher than the LWAC. Creep coefficient of the ULCC was about 47% lower than that of the NWAC but about 18% higher than that of the LWAC. Among five creep models evaluated which tend to over-estimate the creep coefficient of the ULCC, EC2 model gives acceptable prediction within +25% deviations

Water and chloride ion penetration resistance of high-strength ultra lightweight cement composite

Durability is a significant issue to focus on for newly developed structural lightweight cement composite (ULCC). This paper presents an experimental study to evaluate the resistance of ULCC to water and chloride ion penetration. Chloride penetrability and sorptivity were evaluated for ULCC (unit weight about 1450 kg/m3) and compared with those of a normal weight concrete (NWC), a lightweight aggregate concrete (LWC), and an ultra lightweight composite with proprietary cementitious binder (DB) (unit weight about 1450 kg/m3) at similar compressive strength of about 60 MPa. Rapid chloride penetrability test, rapid migration test, water absorption (sorptivity) test, and water permeability test were conducted on these mixtures. Results indicate that ULCC and DB had comparable performance. Compared with control LWC and NWC at similar strength level, the ULCC and DB mixtures had higher resistance to chloride ion penetration, lower water absorption and virtually impermeable to water penetration

Probabilistic based evolutionary optimizers in bi-objective travelling salesman problem

10.1007/978-3-642-17298-4_66Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)6457 LNCS588-59