Static and Dynamic Response of Silty Toyoura Sand with PVA Fibre and Cement Additives

After the Great East Japan Earthquake of 2011, nearly 24 million tons of disaster debris such as concrete products, natural and polymeric fibres, and tsunami deposits remained on the coast of Japan. Much of this debris was recycled and repurposed in engineering projects such as embankments, park restoration, and agricultural field restoration around Tokyo Bay, one of the hardest hit regions of the country. Such a major disaster developed a need for the stabilization of the liquefaction susceptible regions of the reclaimed Tokyo Bay coastline. This thesis specifically focuses on the stabilization against liquefaction of Toyoura sand with the typical silt contents found in the Tokyo Bay region using polyvinyl alcohol (PVA) fibres and Ordinary Portland Cement (OPC). A link between the large strain static and dynamic behavior of the silty sand and the microstructural elements controlling the mechanical response of the amended soil was developed. On a macro scale (Rowe cell, bender element, & cyclic triaxial tests), trends based on cement content, fibre content, silica flour content, and cyclic stress ratio were developed to aid the prediction of the mechanical response of the soil mixture. On a micro scale (SEM and CT scans, mercury intrusion porosimetry), the pore structure, soil structure and soil fabric were visualized to understand the mechanisms underlying these trends. Results from the many tests performed confirmed that the addition of polymer fibres and cement improve the liquefaction resistance, undrained shear strength, and stiffness of silty and clean Toyoura sand. In general, the results suggest that the addition of silica flour is beneficial until a threshold percentage of 28-35% is reached, after which the soil becomes mechanically unstable and more susceptible to static and cyclic liquefaction. The addition of 0-2% fibres provides minimal improvement in all tests. Cement, as expected, improves the soils stiffness and liquefaction resistance proportional to the addition percentage

The effect of infrastructure changes on railway operations.

This paper makes use of standard simulation programs in combination with the tools of applied statistics to simulate railway operations. The purpose of the use of this tool is to evaluate and compare different possible kinds of railway infrastructure, like different types of signaling procedures, different network configuration or operational procedures. A railway system is a logistic network and because of the demand for improved railway operation, much work has been undertaken lately in this scientific field. However the author postulates the hypothesis based on a literature review that in a lot of these works there is a lack of full application of statistics. With this paper the author makes use of standard simulation programs for detailed simulation of railway operation especially with respect to the signaling and operation procedures. Additionally the influence of delays, which occur during real life railway operation is taken into account for a first time. This allows statistical evaluation of the results based on statistical significance. Also sensitivity analysis could be performed. It is demonstrated, that the results of such simulation runs show superior results when compared to other techniques not taking into account the variability. Additionally, procedures were developed to find the capacity of a railway network with the help of additional software tools. In this work the software package ARENA is used to simulate the operation of trains in railway networks. For this approach two major obstacles have to be solved: the simulation of train travelling times and the simulation of block rules used in railway operation. By introduction of visualization the confidence in the results of simulation, even for stakeholders not familiar with this technique, is increased. In this paper it is shown that with ARENA it is possible to calculate the capacity of different railway networks (scenarios). The results, which are calculated using quasi steady state simulation without variation, are similar to those obtained with other calculation methods. Additionally in one scenario the rule of thumb for the quotient between theoretical capacity and practical capacity in a railway network is confirmed by simulation including random variation. It is also demonstrated that OptQuest, an additional software package available for ARENA, is a suitable tool to find near optimal timetables in a scenario including delays. The results of this work may be not only of interest for railway operators, but also for operators of other automated transport systems. Such systems may be unmanned transport vehicles in a factory, transporting goods between different manufacturing stations. But also for automation of road traffic the results may be of interest

First experiences with Personal Networks as an enabling platform for service providers

By developing demonstrators and performing small-scale user trials, we found various opportunities and pitfalls for deploying personal networks (PNs) on a commercial basis. The demonstrators were created using as many as possible legacy devices and proven technologies. They deal with applications in the health sector, home services, tourism, and the transportation sector. This paper describes the various architectures and our experiences with the end users and the technology. We conclude that context awareness, service discovery, and content management are very important in PNs and that a personal network provider role is necessary to realize these functions under the assumptions we made. The PNPay Travel demonstrator suggests that PN service platforms provide an opportunity to develop true trans-sector services

Phase Diagram of the BCC S=1/2 Heisenberg Antiferromagnet with First and Second Neighbor Exchange

We use linked-cluster series expansions, both at T=0 and high temperature, to analyse the phase structure of the spin-\half Heisenberg antiferromagnet with competing first and second-neighbor interactions on the 3-dimensional body-centred-cubic lattice. At zero temperature we find a first-order quantum phase transition at $J_2/J_1 \simeq 0.705 \pm 0.005$ between AF$_1$ (Ne\'el) and AF$_2$ ordered phases. The high temperature series yield quite accurate estimates of the bounding critical line for the AF$_1$ phase, and an apparent critical line for the AF$_2$ phase, with a bicritical point at $J_1/J_2\simeq 0.71$, $kT/J_1\simeq 0.34$. The possibility that this latter transition is first-order cannot be excluded.Comment: 10 pages, 4 figure

CP--odd Correlation in the Decay of Neutral Higgs Boson into ZZZZ, W+W−W^+W^-, or ttˉt{\bar t}

We investigate the possibility of detecting CP--odd angular correlations in the various decay modes of the neutral Higgs boson including the modes of a $ZZ$ pair, a $W^+W^-$ pair, or a heavy quark pair. It is a natural way to probe the CP character of the Higgs boson once it is identified. Final state interactions (i.e. the absorptive decay amplitude) is not required in such correlations. As an illustrative example we take the fundamental source of the CP nonconservation to be in the Yukawa couplings of the Higgs boson to the heavy fermions. A similar correlation in the process $e^+e^- \to l^+ l^- H$ is also proposed. Our analysis of these correlations will be useful for experiments in future colliders such as LEP II, SSC, LHC or NLC.Comment: 16 pages, plus 8 postscript graphs not posted befor

Geometrical locus of massive test particle orbits in the space of physical parameters in Kerr space-time

Gravitational radiation of binary systems can be studied by using the adiabatic approximation in General Relativity. In this approach a small astrophysical object follows a trajectory consisting of a chained series of bounded geodesics (orbits) in the outer region of a Kerr Black Hole, representing the space time created by a bigger object. In our paper we study the entire class of orbits, both of constant radius (spherical orbits), as well as non-null eccentricity orbits, showing a number of properties on the physical parameters and trajectories. The main result is the determination of the geometrical locus of all the orbits in the space of physical parameters in Kerr space-time. This becomes a powerful tool to know if different orbits can be connected by a continuous change of their physical parameters. A discussion on the influence of different values of the angular momentum of the hole is given. Main results have been obtained by analytical methods.Comment: 26 pages, 12 figure

Relativistic ponderomotive force, uphill acceleration, and transition to chaos

Starting from a covariant cycle-averaged Lagrangian the relativistic oscillation center equation of motion of a point charge is deduced and analytical formulae for the ponderomotive force in a travelling wave of arbitrary strength are presented. It is further shown that the ponderomotive forces for transverse and longitudinal waves are different; in the latter, uphill acceleration can occur. In a standing wave there exists a threshold intensity above which, owing to transition to chaos, the secular motion can no longer be described by a regular ponderomotive force. PACS number(s): 52.20.Dq,05.45.+b,52.35.Mw,52.60.+hComment: 8 pages, RevTeX, 3 figures in PostScript, see also http://www.physik.th-darmstadt.de/tqe

Josephson vortices and solitons inside pancake vortex lattice in layered superconductors

In very anisotropic layered superconductors a tilted magnetic field generates crossing vortex lattices of pancake and Josephson vortices (JVs). We study the properties of an isolated JV in the lattice of pancake vortices. JV induces deformations in the pancake vortex crystal, which, in turn, substantially modify the JV structure. The phase field of the JV is composed of two types of phase deformations: the regular phase and vortex phase. The phase deformations with smaller stiffness dominate. The contribution from the vortex phase smoothly takes over with increasing magnetic field. We find that the structure of the cores experiences a smooth yet qualitative evolution with decrease of the anisotropy. At large anisotropies pancakes have only small deformations with respect to position of the ideal crystal while at smaller anisotropies the pancake stacks in the central row smoothly transfer between the neighboring lattice positions forming a solitonlike structure. We also find that even at high anisotropies pancake vortices strongly pin JVs and strongly increase their viscous friction.Comment: 22 pages, 11 figures, to appear in Phys. Rev.

Neutron stars in generalized f(R) gravity

Quartic gravity theory is considered with the Einstein-Hilbert Lagrangean $R+aR^{2}+bR_{\mu \nu}R^{\mu \nu},$ $R_{\mu \nu}$ being Ricci\'s tensor and R the curvature scalar. The parameters $a$ and $b$ are taken of order 1 km$^{2}.$ Arguments are given which suggest that the effective theory so obtained may be a plausible approximation of a viable theory. A numerical integration is performed of the field equations for a free neutron gas. As in the standard Oppenheimer-Volkoff calculation the star mass increases with increasing central density until about 1 solar mass and then decreases. However a dramatic difference exists in the behaviour of the baryon number, which increases monotonically. The calculation suggests that the theory allows stars in equilibrium with arbitrary baryon number, no matter how large.Comment: Keywords: stars, neutron stars; gravity; modified gravity Accepted in Astrophysics and Space Scienc