Humanitarian Demining and Robotics

Mines were used for the first time during the American Civil War in the United States (1861-1865). Anti-tank mines were later ameliorated and laid on the battlefields of the First World War. Mine clearing operations did not pose major problems with those visible and easy-to-detect anti-tank mines. The reason why Anti-personnel mines have been conceived and systematically used on the anti-tank minefields during the Second World War was because such mines prevented the enemy from easy demining of the defense system

A decade of dental education: Faculty of Dentistry

Published on the occasion of the 10th anniversary of the faculty.Incudes bibliographical references.published_or_final_versionConservative dentistry: achievements and perspectives 47Congratulations Wang, Gungwu Wang, Gungwu viiForeword Wei, Stephen H.Y. Wei, Stephen H.Y. ixAcknowledgements Wei, Stephen H.Y. Wei, Stephen H.Y. xiThe Prince Philip Dental Hospital 1Departments and units: a decade of activities and progressStudents' life in the faculty 151Alumni 155Faculty of Dentistry - dental graduates 1985-1992 157The next decade and beyond - some prospects in dentistry 175Brief history of the Faculty of Dentistry 1Administration and governance 4Other services 7Children's dentistry and orthodontics: achievemnets and perspective 13Oral and maxillofacial survey: achievements and perspectives 69Periodontology and public health: achievements and perspectives 95Prosthetic dentistry: achievements and perspectives 113Dental technology unit 125Dental materials science unit: achievements and perspectives 131Oral Biology Unit: achievements and perspectives 139Optimizing adhesion with mineralized dental tissues Gwinnett, A. John Gwinnett, A.John 177Conservative approach to esthetic dentistry Suzuki, M. Mike Suzuki, M. Mike 183The wonderful world of glass ionomer cements Mount, Graham J. Mount, Graham J. 189Biocompatibility of dental materials Smith, Dennis C. Smith, Dennis C. 197Esthetic implant restorations Lewis, Steven Lewis, Steven 203Chemicals in the treatment of periodontal diseases Gjermo, Per Gjermo, Per 21

Slow equivariant lump dynamics on the two sphere

The low-energy, rotationally equivariant dynamics of n CP^1 lumps on S^2 is studied within the approximation of geodesic motion in the moduli space of static solutions. The volume and curvature properties of this moduli space are computed. By lifting the geodesic flow to the completion of an n-fold cover of the moduli space, a good understanding of nearly singular lump dynamics within this approximation is obtained.Comment: 12 pages, 3 figure

Gravitating monopoles in SU(3) gauge theory

We consider the Einstein-Yang-Mills-Higgs equations for an SU(3) gauge group in a spherically symmetric ansatz. Several properties of the gravitating monopole solutions are obtained an compared with their SU(2) counterpart.Comment: 7 pages, Latex, 3 figure

Power dependent switching of nonlinear trapping by local photonic potentials

We study experimentally and numerically the nonlinear scattering of wave packets by local multi-site guiding centers embedded in a continuous dielectric medium, as a function of the input power and angle of incidence. The extent of trapping into the linear modes of different sites is manipulated as a function of both the input power and incidence angle, demonstrating power-controlled switching of nonlinear trapping by local photonic potentials.Comment: Submitted to Optics Letter

Chern-Simons Solitons, Toda Theories and the Chiral Model

The two-dimensional self-dual Chern--Simons equations are equivalent to the conditions for static, zero-energy solutions of the $(2+1)$-dimensional gauged nonlinear Schr\"odinger equation with Chern--Simons matter-gauge dynamics. In this paper we classify all finite charge $SU(N)$ solutions by first transforming the self-dual Chern--Simons equations into the two-dimensional chiral model (or harmonic map) equations, and then using the Uhlenbeck--Wood classification of harmonic maps into the unitary groups. This construction also leads to a new relationship between the $SU(N)$ Toda and $SU(N)$ chiral model solutions

Collision-Induced Decay of Metastable Baby Skyrmions

Many extensions of the standard model predict heavy metastable particles which may be modeled as solitons (skyrmions of the Higgs field), relating their particle number to a winding number. Previous work has shown that the electroweak interactions admit processes in which these solitons decay, violating standard model baryon number. We motivate the hypothesis that baryon-number-violating decay is a generic outcome of collisions between these heavy particles. We do so by exploring a 2+1 dimensional theory which also possesses metastable skyrmions. We use relaxation techniques to determine the size, shape and energy of static solitons in their ground state. These solitons could decay by quantum mechanical tunneling. Classically, they are metastable: only a finite excitation energy is required to induce their decay. We attempt to induce soliton decay in a classical simulation by colliding pairs of solitons. We analyze the collision of solitons with varying inherent stabilities and varying incident velocities and orientations. Our results suggest that winding-number violating decay is a generic outcome of collisions. All that is required is sufficient (not necessarily very large) incident velocity; no fine-tuning of initial conditions is required.Comment: 24 pages, 7 figures, latex. Very small changes onl

Magnetothermodynamics of BPS baby skyrmions

The magnetothermodynamics of skyrmion type matter described by the gauged BPS baby Skyrme model at zero temperature is investigated. We prove that the BPS property of the model is preserved also for boundary conditions corresponding to an asymptotically constant magnetic field. The BPS bound and the corresponding BPS equations saturating the bound are found. Further, we show that one may introduce pressure in the gauged model by a redefinition of the superpotential. Interestingly, this is related to non-extremal type solutions in the so-called fake supersymmetry method. Finally, we compute the equation of state of magnetized BSP baby skyrmions inserted into an external constant magnetic field $H$ and under external pressure $P$, i.e., $V=V(P,H)$, where $V$ is the "volume" (area) occupied by the skyrmions. We show that the BPS baby skyrmions form a ferromagnetic medium.Comment: Latex, 39 pages, 14 figures. v2: New results and references added, physical interpretation partly change

Two Skyrmion Dynamics with Omega Mesons

We present our first results of numerical simulations of two skyrmion dynamics using an $\omega$-meson stabilized effective Lagrangian. We consider skyrmion-skyrmion scattering with a fixed initial velocity of $\beta=0.5$, for various impact parameters and groomings. The physical picture that emerges is surprisingly rich, while consistent with previous results and general conservation laws. We find meson radiation, skyrmion scattering out of the scattering plane, orbiting and capture to bound states.Comment: 19 pages, 22 figure