Joint Contribution to the Deformation of RC Beam-Column Sub-Assemblies

In this paper, the contribution of joint shear deformation to the overall storey-drift of reinforced concrete (RC) beam-column sub-assemblies is investigated experimentally. Two lightly reinforced beamcolumn sub-assemblies, one without any hoops inside the joint core and the other with hoops significantly less than that required by the incumbent seismic design codes, were tested under a constant axial compression and gradually increasing reversed cyclic displacements. Both specimens experienced severe damage in the joint due to excessive shear deformation of the joint core. Unlike in seismically designed ductile frames, joint shear deformation accounted for more than 50% of the overall storey-drift in the tested specimens. Comparison of the two test results showed that a small amount of hoops in the joint core, though not enough to satisfy seismic requirements, helps to confine the joint core and to inhibit the joint shear deformation to some extent

Probabilistic instantaneous quantum computation

The principle of teleportation can be used to perform a quantum computation even before its quantum input is defined. The basic idea is to perform the quantum computation at some earlier time with qubits which are part of an entangled state. At a later time a generalized Bell state measurement is performed jointly on the then defined actual input qubits and the rest of the entangled state. This projects the output state onto the correct one with a certain exponentially small probability. The sufficient conditions are found under which the scheme is of benefit.Comment: 4 pages, 1 figur

Modularisation strategies in the AEC industry:a comparative analysis

Many industries have benefited from modularisation; while in the architecture, engineering and construction (AEC) industry, the concept of modularisation is associated with dimensional coordination. This has added to an already extensive list of challenges due to market size and the concept of economies of scale in AEC industry, to name but a few. Moreover, there is a myth that the AEC industry is bound to stay associated with build-to-order or made-to-order approach caused the AEC industry to restrict modularisation to the component level. This changes the balance in favour of what this paper calls a bottom-up approach. On the other hand, a valid alternative strategy–referred to in this study as top-down strategy–remains very much underexploited. The clients, therefore, do not have a neutral means by which they can assess which strategy is in their best interest. Likewise, if a construction company plans to make a strategic move towards the principles of modularisation and off-site manufacturing, they do not have clear decision support tools. This study investigates these two main modularisation strategies in the AEC industry to provide some examples of successful cases regarding how, when and where such strategy have been applied by different construction companies in different cases. The collected and collated empirical data and the results from the interviews will help clients and companies to analyse their own cases and make operational decisions on how, when and where to best utilise the bottom-up and top-down modularisation techniques while considering the pros and cons of such decisions

Formation of Small-Scale Condensations in the Molecular Clouds via Thermal Instability

A systematic study of the linear thermal instability of a self-gravitating magnetic molecular cloud is carried out for the case when the unperturbed background is subject to local expansion or contraction. We consider the ambipolar diffusion, or ion-neutral friction on the perturbed states. In this way, we obtain a non-dimensional characteristic equation that reduces to the prior characteristic equation in the non-gravitating stationary background. By parametric manipulation of this characteristic equation, we conclude that there are, not only oblate condensation forming solutions, but also prolate solutions according to local expansion or contraction of the background. We obtain the conditions for existence of the Field lengths that thermal instability in the molecular clouds can occur. If these conditions establish, small-scale condensations in the form of spherical, oblate, or prolate may be produced via thermal instability.Comment: 16 page, accepted by Ap&S

Electronic Theory for the Nonlinear Magneto-Optical Response of Transition-Metals at Surfaces and Interfaces: Dependence of the Kerr-Rotation on Polarization and on the Magnetic Easy Axis

We extend our previous study of the polarization dependence of the nonlinear optical response to the case of magnetic surfaces and buried magnetic interfaces. We calculate for the longitudinal and polar configuration the nonlinear magneto-optical Kerr rotation angle. In particular, we show which tensor elements of the susceptibilities are involved in the enhancement of the Kerr rotation in nonlinear optics for different configurations and we demonstrate by a detailed analysis how the direction of the magnetization and thus the easy axis at surfaces and buried interfaces can be determined from the polarization dependence of the nonlinear magneto-optical response, since the nonlinear Kerr rotation is sensitive to the electromagnetic field components instead of merely the intensities. We also prove from the microscopic treatment of spin-orbit coupling that there is an intrinsic phase difference of 90$^{\circ }$ between tensor elements which are even or odd under magnetization reversal in contrast to linear magneto-optics. Finally, we compare our results with several experiments on Co/Cu films and on Co/Au and Fe/Cr multilayers. We conclude that the nonlinear magneto-optical Kerr-effect determines uniquely the magnetic structure and in particular the magnetic easy axis in films and at multilayer interfaces.Comment: 23 pages Revtex, preprintstyle, 2 uuencoded figure

The phase diagram of quantum systems: Heisenberg antiferromagnets

A novel approach for studying phase transitions in systems with quantum degrees of freedom is discussed. Starting from the microscopic hamiltonian of a quantum model, we first derive a set of exact differential equations for the free energy and the correlation functions describing the effects of fluctuations on the thermodynamics of the system. These equations reproduce the full renormalization group structure in the neighborhood of a critical point keeping, at the same time, full information on the non universal properties of the model. As a concrete application we investigate the phase diagram of a Heisenberg antiferromagnet in a staggered external magnetic field. At long wavelengths the known relationship to the Quantum Non Linear Sigma Model naturally emerges from our approach. By representing the two point function in an approximate analytical form, we obtain a closed partial differential equation which is then solved numerically. The results in three dimensions are in good agreement with available Quantum Monte Carlo simulations and series expansions. More refined approximations to the general framework presented here and few applications to other models are briefly discussed.Comment: 17 pages, 7 figure

A weakly stable algorithm for general Toeplitz systems

We show that a fast algorithm for the QR factorization of a Toeplitz or Hankel matrix A is weakly stable in the sense that R^T.R is close to A^T.A. Thus, when the algorithm is used to solve the semi-normal equations R^T.Rx = A^Tb, we obtain a weakly stable method for the solution of a nonsingular Toeplitz or Hankel linear system Ax = b. The algorithm also applies to the solution of the full-rank Toeplitz or Hankel least squares problem.Comment: 17 pages. An old Technical Report with postscript added. For further details, see http://wwwmaths.anu.edu.au/~brent/pub/pub143.htm

Search for the glueball candidates f0(1500) and fJ(1710) in gamma gamma collisions

Data taken with the ALEPH detector at LEP1 have been used to search for gamma gamma production of the glueball candidates f0(1500) and fJ(1710) via their decay to pi+pi-. No signal is observed and upper limits to the product of gamma gamma width and pi+pi- branching ratio of the f0(1500) and the fJ(1710) have been measured to be Gamma_(gamma gamma -> f0(1500)). BR(f0(1500)->pi+pi-) < 0.31 keV and Gamma_(gamma gamma -> fJ(1710)). BR(fJ(1710)->pi+pi-) < 0.55 keV at 95% confidence level.Comment: 10 pages, 3 figure