57,047 research outputs found
A New Model for Evaluating the Future Options of Integrating Ground Source Heat Pumps in Building Construction
Decision-making for effective infrastructure integration is challenging because the performances of long-lasting objects
often depends on conditions which are either outside the control of the designer or difficult to foresee at the design
stage. In this paper we examine a new approach to estimating the range of cost-effective solutions for integrating
the construction/retrofit of two or more different types of infrastructure. Infrastructure integration has many perceived
benefits, but also faces serious new challenges and doubts from practitioners, particularly in sectors with complex
construction process, long asset lives, uncertain cost parameters, and slow and unwieldy decision-making, such as
is common with civil engineering works. We test all main options in integrating a ground source heat pump (GSHP)
system with the construction and retrofit of an archetypal, office building. A new simulation model is developed and
parameterized using actual data in the UK. We incorporate unavoidable uncertainties and randomness in how the
decisions are triggered, and test the effectiveness of proactive measures to embed future options. The model highlights
how sensitive the range of cost-effective solutions is to the setting of renewable energy incentives, discount rates,
technical performance and life-cycle asset management of interdependent infrastructure. This points to a clear need for
establishing appropriate regulatory standards. We expect this model to find increasing applications in the planning and
designing of integrated complexes of buildings, transport facilities, renewable energy supply, water supply and waste
management in dense urban areas, which are an increasingly key part of sustainable urban development
Coexistence of full which-path information and interference in Wheelers delayed choice experiment with photons
We present a computer simulation model that is a one-to-one copy of an
experimental realization of Wheeler's delayed choice experiment that employs a
single photon source and a Mach-Zehnder interferometer composed of a 50/50
input beam splitter and a variable output beam splitter with adjustable
reflection coefficient (V. Jacques {\sl et al.}, Phys. Rev. Lett. 100,
220402 (2008)). For , experimentally measured values of the
interference visibility and the path distinguishability , a parameter
quantifying the which-path information WPI, are found to fulfill the
complementary relation , thereby allowing to obtain partial WPI
while keeping interference with limited visibility. The simulation model that
is solely based on experimental facts, that satisfies Einstein's criterion of
local causality and that does not rely on any concept of quantum theory or of
probability theory, reproduces quantitatively the averages calculated from
quantum theory. Our results prove that it is possible to give a particle-only
description of the experiment, that one can have full WPI even if D=0, V=1 and
therefore that the relation cannot be regarded as quantifying
the notion of complementarity.Comment: Physica E, in press; see also http://www.compphys.ne
Induced fission of 240Pu
We study the fission dynamics of 240Pu within an implementation of the
Density Functional Theory (DFT) extended to superfluid systems and real-time
dynamics. We demonstrate the critical role played by the pairing correlations.
The evolution is found to be much slower than previously expected in this fully
non-adiabatic treatment of nuclear dynamics, where there are no symmetry
restrictions and all collective degrees of freedom (CDOF) are allowed to
participate in the dynamics.Comment: 8 pages, 4 figures, talk given at The 6th International Conference on
Fission and Properties of Neutron-Rich Nuclei, Sanibel Island, Florida,
November 6-2 (2016
Global Models of Planet Formation and Evolution
Despite the increase in observational data on exoplanets, the processes that
lead to the formation of planets are still not well understood. But thanks to
the high number of known exoplanets, it is now possible to look at them as a
population that puts statistical constraints on theoretical models. A method
that uses these constraints is planetary population synthesis. Its key element
is a global model of planet formation and evolution that directly predicts
observable planetary properties based on properties of the natal protoplanetary
disk. To do so, global models build on many specialized models that address one
specific physical process. We thoroughly review the physics of the sub-models
included in global formation models. The sub-models can be classified as models
describing the protoplanetary disk (gas and solids), the (proto)planet (solid
core, gaseous envelope, and atmosphere), and finally the interactions
(migration and N-body interaction). We compare the approaches in different
global models and identify physical processes that require improved
descriptions in future. We then address important results of population
synthesis like the planetary mass function or the mass-radius relation. In
these results, the global effects of physical mechanisms occurring during
planet formation and evolution become apparent, and specialized models
describing them can be put to the observational test. Due to their nature as
meta models, global models depend on the development of the field of planet
formation theory as a whole. Because there are important uncertainties in this
theory, it is likely that global models will in future undergo significant
modifications. Despite this, they can already now yield many testable
predictions. With future global models addressing the geophysical
characteristics, it should eventually become possible to make predictions about
the habitability of planets.Comment: 30 pages, 16 figures. Accepted for publication in the International
Journal of Astrobiology (Cambridge University Press
Thermodynamics of lattice QCD with 2 flavours of colour-sextet quarks: A model of walking/conformal Technicolor
QCD with two flavours of massless colour-sextet quarks is considered as a
model for conformal/walking Technicolor. If this theory possess an infrared
fixed point, as indicated by 2-loop perturbation theory, it is a
conformal(unparticle) field theory. If, on the other hand, a chiral condensate
forms on the weak-coupling side of this would-be fixed point, the theory
remains confining. The only difference between such a theory and regular QCD is
that there is a range of momentum scales over which the coupling constant runs
very slowly (walks). In this first analysis, we simulate the lattice version of
QCD with two flavours of staggered quarks at finite temperatures on lattices of
temporal extent and 6. The deconfinement and chiral-symmetry
restoration couplings give us a measure of the scales associated with
confinement and chiral-symmetry breaking. We find that, in contrast to what is
seen with fundamental quarks, these transition couplings are very different.
for each of these transitions increases significantly from
and as expected for the finite temperature transitions of an
asymptotically-free theory. This suggests a walking rather than a conformal
behaviour, in contrast to what is observed with Wilson quarks. In contrast to
what is found for fundamental quarks, the deconfined phase exhibits states in
which the Polyakov loop is oriented in the directions of all three cube roots
of unity. At very weak coupling the states with complex Polyakov loops undergo
a transition to a state with a real, negative Polyakov loop.Comment: 21 pages, 9 figures, Revtex with postscript figures. One extra
reference was added; text is unchanged. Corrected typographical erro
Real time description of fission
Using the time-dependent superfluid local density approximation, the dynamics
of fission is investigated in real time from just beyond the saddle to fully
separated fragments. Simulations produced in this fully microscopic framework
can help to assess the validity of the current approaches to fission, and to
obtain estimate of fission observables. In this contribution, we concentrate on
general aspects of fission dynamics.Comment: Proceedings of the "15th Varenna Conference on Nuclear Reaction
Mechanisms," Varenna, Italy, June 201
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