3 research outputs found
Heat diffusion in a two-dimensional thermal fuse model
We present numerical studies of electrical breakdown in disordered materials
using a two-dimensional thermal fuse model with heat diffusion. A conducting
fuse is heated locally by a Joule heating term. Heat diffuses to neighbouring
fuses by a diffusion term. When the temperature reaches a given threshold, the
fuse breaks and turns into an insulator. The time dynamics is governed by the
time scales related to the two terms, in the presence of quenched disorder in
the conductances of the fuses. For the two limiting domains, when one time
scale is much smaller than the other, we find that the global breakdown time
follows and , where is the applied
current, and is the system size. However, such power law does not apply in
the intermediate domain where the competition between the two terms produces a
subtle behaviour.Comment: Physical Review E 81, 066111 (2010
Anomalous Scaling and Solitary Waves in Systems with Non-Linear Diffusion
We study a non-linear convective-diffusive equation, local in space and time,
which has its background in the dynamics of the thickness of a wetting film.
The presence of a non-linear diffusion predicts the existence of fronts as well
as shock fronts. Despite the absence of memory effects, solutions in the case
of pure non-linear diffusion exhibit an anomalous sub-diffusive scaling. Due to
a balance between non-linear diffusion and convection we, in particular, show
that solitary waves appear. For large times they merge into a single solitary
wave exhibiting a topological stability. Even though our results concern a
specific equation, numerical simulations supports the view that anomalous
diffusion and the solitary waves disclosed will be general features in such
non-linear convective-diffusive dynamics.Comment: Corrected typos, added 3 references and 2 figure
Design and model test of a soft-connected lattice-structured floating solar photovoltaic concept for harsh offshore conditions
Various types of floating solar photovoltaic (FPV) devices have been previously proposed,
designed and constructed with applications primarily limited to onshore water bodies or nearshore regions with benign environmental conditions. This paper proposes a novel FPV concept
which can survive harsh environmental conditions with extreme wave heights above 10 m. This
concept uses standardised lightweight semi-submersible floats made of circular materials as individual modules. The floating modules are soft connected with ropes to form an FPV array. We
first present the conceptual design of the floats and the connection systems, including hydrostatic,
hydrodynamic, and structural assessments of the floats. To verify the motion response performance, we carried out 1:60 scaled model tests for a 2 by 3 array under regular and irregular wave
conditions. From the time series and response spectra, the motion characteristics of the array and
the mooring responses are analysed in detail. The proposed concept exhibits excellent performances in terms of modular motions with limited wave overtopping and no contact is observed
between adjacent modules under the extreme wave conditions. The findings of this study can
serve as a valuable reference to developing reliable and cost-effective FPV technologies for
offshore conditions.publishedVersio