61,603 research outputs found
The effects of protected beams and their connections on the fire resistance of composite buildings
According to full-scale fire tests, it is noticed that tensile membrane action within the concrete floor slabs plays an important role in affecting the fire resistance of composite buildings. It is well known that the development of tensile membrane actions relies on the vertical support along the edges of the slab panel. However, there is at present a lack of research into the influence of vertical supports on the tensile membrane actions of the floor slabs. In this paper, the performances of a generic three dimensional 45m x 45m composite floor subjected to ISO834 Fire and Natural Fire are investigated. Different vertical support conditions and three steel meshes are applied in order to assess the impact of vertical supports on tensile membrane action of floor slabs. Unlike other existing large scale modelling which assumes the connections behave as pinned or rigid for simplicity, two robust 2-node connection element models developed by the authors are used to model the behaviour of end-plate and partial end-plate connections of composite structures under fire conditions. The impact of connections on the 3D behaviour of composite floor is taken into consideration. The load-transfer mechanisms of composite floor when connections fail due to axial tension, vertical shear and bending are investigated. Based on the results obtained, some design recommendations are proposed to enhance the fire resistance of composite buildings
Topologically Robust Transport of Photons in a Synthetic Gauge Field
Electronic transport in low dimensions through a disordered medium leads to
localization. The addition of gauge fields to disordered media leads to
fundamental changes in the transport properties. For example, chiral edge
states can emerge in two-dimensional systems with a perpendicular magnetic
field. Here, we implement a "synthetic'' gauge field for photons using
silicon-on-insulator technology. By determining the distribution of transport
properties, we confirm the localized transport in the bulk and the suppression
of localization in edge states, using the "gold standard'' for localization
studies. Our system provides a new platform to investigate transport properties
in the presence of synthetic gauge fields, which is important both from the
fundamental perspective of studying photonic transport and for applications in
classical and quantum information processing.Comment: 4.5 pages, 3 figures and supplementary materia
Inversion formula and Parsval theorem for complex continuous wavelet transforms studied by entangled state representation
In a preceding Letter (Opt. Lett. 32, 554 (2007)) we have proposed complex
continuous wavelet transforms (CCWTs) and found Laguerre--Gaussian mother
wavelets family. In this work we present the inversion formula and Parsval
theorem for CCWT by virtue of the entangled state representation, which makes
the CCWT theory complete. A new orthogonal property of mother wavelet in
parameter space is revealed.Comment: 4 pages no figur
A Simple Kinetic Analysis of Syngas During Steam Hydrogasification of Biomass Using a Novel Inverted Batch Reactor with Instant High Pressure Feeding
A newly designed inverted batch reactor equipped with a pressure-driven feeding system was built for investigating the kinetics of syngas during the steam hydrogasification (SHR) of biomass. The system could instantly load the feedstock into the reactor at high temperature and pressure, which simulated the way to transport the feedstock into a hot and pressurized gasifier. Experiments were conducted from 600 °C to 700 °C. The inverted reactor showed very high heating rate by enhancing the carbon conversion and syngas production. The kinetic study showed that the rates of CH4, CO and CO2 formation during SHR were increased when the gasification temperature went up. SHR had comparatively lower activation energy for CH4 production. The activation energies of CH4, CO and CO2 during SHR were 42.8, 51.8 and 14 kJ/mol, respectively
Efficient quantum computation within a disordered Heisenberg spin-chain
We show that efficient quantum computation is possible using a disordered
Heisenberg spin-chain with `always-on' couplings. Such disorder occurs
naturally in nanofabricated systems. Considering a simple chain setup, we show
that an arbitrary two-qubit gate can be implemented using just three
relaxations of a controlled qubit, which amounts to switching the on-site
energy terms at most twenty-one times.Comment: To appear in Phys. Rev.
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