338 research outputs found
Case Histories of Foundations on Top of a Rupturing Normal Fault During the Kocaeli 1999 Earthquake
Although the Kocaeli (Turkey) earthquake was triggered by reactivation of the North Anatolian strike-slip Fault, normal faulting also occurred within the pull-apart basin of Gölcük. Its effect on overlying structures is summarized in this paper. The normal rupture caused maximum vertical displacements of up to 2.5m. Several structures were crossed by the rupture. As expected, many of them either collapsed or were severely damaged. Surprisingly, several structures survived the dislocation with no damage, while in some cases the rupture deviated, “avoiding” the structures. The foundations of the involved structures comprised a variety of types, ranging from simple separate footings to box foundation and to piled foundation. The paper provides a comprehensive description of the observed fault-foundation interaction patterns, accompanied by the results of soil exploration and geological trenching. Each structure is analyzed through the use of finite element modelling to reveal the main aspects of Fault Rupture––Soil–Foundation–Structure Interaction (FR–SFSI)
One-loop adjoint masses for branes at non-supersymmetric angles
This proceeding is based on arXiv:1105.0591 [hep-th] where we consider
breaking of supersymmetry in intersecting D-brane configurations by slight
deviation of the angles from their supersymmetric values. We compute the masses
generated by radiative corrections for the adjoint scalars on the brane
world-volumes. In the open string channel, the string two-point function
receives contributions only from the infrared limits of N~4 and N~2
supersymmetric configurations, via messengers and their Kaluza-Klein
excitations, and leads at leading order to tachyonic directions.Comment: 15 pages, 5 figures. Contribution to the proceedings of the Corfu
Summer Institute 2011 School and Workshops on Elementary Particle Physics and
Gravity, September 4-18 2011 Corfu, Greec
Phenomenological analysis of D-brane Pati-Salam vacua
In the present work we perform a phenomenological analysis of the effective
low energy models with Pati-Salam (PS) gauge symmetry derived in the context of
D-branes. A main issue in these models arises from the fact that the
right-handed fermions and the PS-symmetry breaking Higgs field transform
identically under the PS symmetry, causing unnatural matter-Higgs mixing
effects. We argue that this problem could be solved in particular D-brane
setups where these fields arise in different intersections. We further observe
that whenever a large Higgs mass term is generated in a particular class of
mass spectra, a splitting mechanism -reminiscent of the doublet triplet
splitting- may protect the neutral Higgs components from a heavy mass term. We
analyze the implications of each individual representation which in principle
is available in these models in order to specify the minimal spectrum required
to build up a consistent PS model which reconciles the low energy data. A short
discussion is devoted on the effects of stringy instanton corrections,
particularly those generating missing Yukawa couplings and contributing to the
fermion mass textures. We discuss the correlations of the intersecting D-brane
spectra with those obtained from Gepner constructions and analyze the
superpotential, the resulting mass textures and the low energy implications of
some examples of the latter along the lines proposed above.Comment: 50 pages, 3 figures (v2 - Minor corrections
Recommended from our members
The development of a process for the production of textiles with fully embedded electronics
Many attempts to combine Electronics and Textiles have been realised for many years now. At the beginning with the introduction of conductive wires, then with the introduction of sensors and more complex circuits onto an everyday garment. The next step of evolution of combining these seemingly different fields is to integrate the electronics inside a textile structure, so that it will provide a seamless implementation of both worlds into everyday life. The microelectronics, mechanical, electrical, computing and chemical engineering advances of the last years, can ensure that, nowadays, this is feasible. Because of the minuscule dimensions of the electronic components, so that can be integrated inside the thin-by-nature yarn, and the necessity of a flexible and bendable structure overall, the task required is not of a small scale and has no prerequisite. This Thesis provides the backbone of an innovative technique to achieve the above goal in an automated or semi-automated, accurate, repeatable, reliable and time-cost effective way, combining all the required procedures, outlining the issues and proposing solutions on a plethora of them.
This research's outcome, after both manual and automated implementation of the microelectronic component encapsulation concept, proves that automation of the process is feasible with more research and funding in the future. Because this is an innovative and challenging in its implementation, as far as the tiny dimensions of the electronic components are concerned, more testing and physical implementation must be conducted with the contribution of a team of people from different disciplines, in order to finalise it and produce the first linear and continuous version of the machine that can automatically produce electronic yarns, i.e. yarn with electronic components inside its core.
The importance of this Thesis is that it sets the foundations, guidelines and requirements for the development of an all-new manufacturing procedure and the creation of a new machine, i.e. the Electronic Yarn Machine -EYM- in the future
Scaling laws for shaking table testing of reinforced concrete tunnels accounting for post-cracking lining response
This paper proposes a new set of scaling laws for the study of the post-cracking behaviour of lightly reinforced concrete tunnel linings during 1g shaking table testing. The post-cracking behaviour scaling laws are formulated using two non-dimensional parameters: the brittleness number s, which governs the fracturing phenomenon for unreinforced concrete elements and , which plays a primary role for the stability of the process of concrete fracture and steel plastic flow in reinforced concrete elements. The proposed laws allow for the development of an “adequate” experimental model and are validated using numerical analyses of a reinforced tunnel in rock, in both prototype and 1:30 model scale. The adopted experimental set-up is inspired by an existing 1g physical testing campaign on the seismic response of a concrete tunnel in rock and the postulated laws are shown to grant satisfactory similitude between the cracking behaviour of the model and prototype tunnel under two examined earthquake records. The potential of using the proposed laws in 1g tests for Class A predictions of evolving crack patterns in reinforced concrete tunnels is highlighted. The proposed laws are examined under three possible boundary conditions, indicating that both rigid and laminar boxes can still change the behaviour significantly compared to an envisaged free field boundary model. The analysis shows though that for larger soil to lining stiffness ratios, boundary artefacts could be greatly reduced. The present study provides useful recommendations for future 1g tests that did not exist to date, while the proposed scaling laws allow for versatility in the design of novel tunnel lining model test materials
SU(5) D-brane realizations, Yukawa couplings and proton stability
We discuss SU(5) Grand Unified Theories in the context of orientifold
compactifications. Specifically, we investigate two and three D-brane stack
realizations of the Georgi-Glashow and the flipped SU(5) model and analyze them
with respect to their Yukawa couplings. As pointed out in arXiv:0909.0271 the
most economical Georgi-Glashow realization based on two stacks generically
suffers from a disastrous large proton decay rate. We show that allowing for an
additional U(1) D-brane stack this as well as other phenomenological problems
can be resolved. We exemplify with globally consistent Georgi-Glashow models
based on RCFT that these D-brane quivers can be indeed embedded in a global
setting. These globally consistent realizations admit rigid O(1) instantons
inducing the perturbatively missing coupling 10105^H. Finally we show that
flipped SU(5) D-brane realizations even with multiple U(1) D-brane stacks are
plagued by severe phenomenological drawbacks which generically cannot be
overcome.Comment: 34 pages v2 minor correction
- …