Permanent Displacements and Tilting Angle of Small Footings on Sand

This paper presents the comparison between the proposed theoretical prediction and experimental results of horizontal and vertical permanent displacements, and tilting angle of small rigid square and rectangular footings on relatively uniform sand. Old and new lumped parameters for different modes of vibrations, i.e. horizontal, vertical and rocking vibrations are used in the analysis. Some good agreement is found between the theory with the new lumped parameters and experiments, but the relevant dynamic soil properties are still the most critical parameters that need to be measured. Finally, effects of frequency and rocking heights are also investigated

Development of New Stiffness and Damping Expressions for Footing Vibrations

New expressions for stiffness and radiation damping, which have been developed for a new forcing function, are based on the simple equation of wave propagation in a perfectly elastic half space for different modes of vibrations, particularly vertical and horizontal vibrations. A differential equation including the effect of foundation mass is presented and the results of the amplitudes of vibration obtained from this differential equation are compared with those in the standard differential equation in soil dynamics textbooks. Furthermore, added soil masses for vertical and horizontal vibrations are also derived based on the equation of wave propagation and discussed with other findings. Finally, this paper also compared different ways of using the total damping, which is composed of radiation damping and internal damping

On the energy efficiency of NOMA for wireless backhaul in multi-tier heterogeneous CRAN

This paper addresses the problem of wireless backhaul in a multi-tier heterogeneous cellular network coordinated by a cloud-based central station (CCS), namely heterogeneous cloud radio access network (HCRAN). A non-orthogonal multiple access (NOMA) is adopted in the power domain for improved spectral efficiency and network throughput of the wireless downlink in the HCRAN. We first develop a power allocation for multiple cells of different tiers taking account of the practical power consumption of different cell types and wireless backhaul. By analysing the energy efficiency (EE) of the NOMA for the practical HCRAN downlink, we show that the power available at the cloud, the propagation environment and cell types have significant impacts on the EE performance. In particular, in a large network, the cells located at the cloud edge are shown to suffer from a very poor performance with a considerably degraded EE, which accordingly motivates us to propose an iteration algorithm for determining the maximal number of cells that can be supported in the HCRAN. The results reveal that a double number of cells can be covered in the urban environment compared to those in the shadowed urban environment and more than 1.5 times of the number of microcells can be deployed over the macrocells, while only a half number of cells can be supported when the distance between them increases threefol

Direct observation of dynamic surface acoustic wave controlled carrier injection into single quantum posts using phase-resolved optical spectroscopy

A versatile stroboscopic technique based on active phase-locking of a surface acoustic wave to picosecond laser pulses is used to monitor dynamic acoustoelectric effects. Time-integrated multi-channel detection is applied to probe the modulation of the emission of a quantum well for different frequencies of the surface acoustic wave. For quantum posts we resolve dynamically controlled generation of neutral and charged excitons and preferential injection of holes into localized states within the nanostructure.Comment: 10 pages, 4 figure

Emergence of geometrical optical nonlinearities in photonic crystal fiber nanowires

We demonstrate analytically and numerically that a subwavelength-core dielectric photonic nanowire embedded in a properly designed photonic crystal fiber cladding shows evidence of a previously unknown kind of nonlinearity (the magnitude of which is strongly dependent on the waveguide parameters) which acts on solitons so as to considerably reduce their Raman self-frequency shift. An explanation of the phenomenon in terms of indirect pulse negative chirping and broadening is given by using the moment method. Our conclusions are supported by detailed numerical simulations.Comment: 5 pages, 3 figure

Funneling and frustration in the energy landscapes of some designed and simplified proteins

We explore the similarities and differences between the energy landscapes of proteins that have been selected by nature and those of some proteins designed by humans. Natural proteins have evolved to function as well as fold, and this is a source of energetic frustration. The sequence of Top7, on the other hand, was designed with architecture alone in mind using only native state stability as the optimization criterion. Its topology had not previously been observed in nature. Experimental studies show that the folding kinetics of Top7 is more complex than the kinetics of folding of otherwise comparable naturally occurring proteins. In this paper, we use structure prediction tools, frustration analysis, and free energy profiles to illustrate the folding landscapes of Top7 and two other proteins designed by Takada. We use both perfectly funneled (structure-based) and predictive (transferable) models to gain insight into the role of topological versus energetic frustration in these systems and show how they differ from those found for natural proteins. We also study how robust the folding of these designs would be to the simplification of the sequences using fewer amino acid types. Simplification using a five amino acid type code results in comparable quality of structure prediction to the full sequence in some cases, while the two-letter simplification scheme dramatically reduces the quality of structure prediction

Stabilization and functional properties of La3NiAlMnO9 and La3CoAlMnO9 magnetoelectric triple perovskites

Ferromagnetic La3NiAlMnO9 (LNAMO) and La3CoAlMnO9 (LCAMO) triple-perovskite thin films are stabilized in the 750-860 oC temperature range in 100 to 900 mTorr O2 pressure range using pulsed-laser deposition. The LCAMO and LNAMO films exhibit ferromagnetism up to 190 K and 130 K respectively. The structural, optical and magnetic properties of these films demonstrate that the B-site 3d-cations, Al, Mn and Co or Ni ions, are structurally short-range ordered. The strong spin-lattice-polarization coupling in LCAMO is evidenced by the temperature dependence of the dielectric constant and the softening of the phonon frequencies starting in the vicinity of the ferromagnetic-to-paramagnetic phase transition mimicking the behaviours of La2CoMnO6 double perovskite.Comment: 11 pages, 4 fig