483 research outputs found
Predicting color and short-circuit current of colored BIPV modules
Photovoltaic modules for façade integration should have a widely modifiable appearance to adjust to the architect’s requirements. However, architects today usually have only a limited number of already manufactured samples to choose from. Changing the color will also change the photovoltaic yield. Therefore, it would be helpful to have a procedure that allows us to determine the appearance and expected yield in advance of module fabrication. We present such a method for creating a digital prototype of a colored building integrated photovoltaic module. Using reflectance and external quantum efficiency measurements of eight colored modules, we simulate the appearance and respective energy yield for arbitrary module colors. We validate our predictions for 29 different colored modules. We use textiles that have been colored by printing and laminate them onto the modules to change the appearance of the modules. However, our digital prototyping model is also applicable to other coloring techniques. We achieve an average color difference of ΔE00 = 1.34 between predicted and measured colors, which is barely perceptible to the human eye. The predicted short-circuit current density of the digital prototype deviates on average less than 1% from the measured on
The COVID-19 pandemic and Olympic/Paralympic athletes’ developmental challenges and possibilities in times of a global crisis-transition
Our aim in this invited commentary is to stimulate discussion among sport psychology researchers and practitioners regarding the unique developmental challenges and possibilities that Olympic and Paralympic athletes are undergoing during their final – extended year of the Tokyo 2020 quadrenium. We begin the commentary with COVID-19 pandemic (C-19) context setting, proceed with discussing transitional and holistic perspectives on athletes’ Olympic/Paralympic journey, outline three potential pathway scenarios and “C-19 as a possibility-provider” coping (meta-) scenario for Olympic/Paralympic athletes, and finalise our commentary with a summary of messages intended to invite further discussion and collaboration
Community acceptance of large-scale solar energy installations in developing countries: Evidence from Morocco
Renewable energy production is climbing the public agenda in many countries in the Middle East and North Africa (MENA region), for reasons of energy security, independence and local value creation. While technical and economic barriers are largely understood, in this paper we investigate the issue of community acceptance. In so doing, we explore the importance of relevant drivers of community acceptance such as level of expected socio-economic and environmental impacts, procedural and distributive justice, and trust. We conducted 232 face-to-face interviews with the local population in Ouarzazate in Morocco, the building site of a flagship project for concentrated solar power in the MENA region. We find that community acceptance is almost universal, particularly because solar power is perceived to be environmentally friendly. At the same time perceived level of knowledge about the project is very low, which is positively linked to the high level of acceptance. Our data suggest that there may be some social desirability bias distorting community acceptance; only long-term experience with the project will show whether hopes for job creation will be fulfilled and high levels of acceptance can be maintained
Description of electricity generation technologies. Middle East North Africa Sustainable Electricity Trajectories (MENA-SELECT) project
Semiclassical Mechanism for the Quantum Decay in Open Chaotic Systems
We address the decay in open chaotic quantum systems and calculate
semiclassical corrections to the classical exponential decay. We confirm random
matrix predictions and, going beyond, calculate Ehrenfest time effects. To
support our results we perform extensive numerical simulations. Within our
approach we show that certain (previously unnoticed) pairs of interfering,
correlated classical trajectories are of vital importance. They also provide
the dynamical mechanism for related phenomena such as photo-ionization and
-dissociation, for which we compute cross section correlations. Moreover, these
orbits allow us to establish a semiclassical version of the continuity
equation.Comment: 4 pages, 2 figure
Random matrix description of decaying quantum systems
This contribution describes a statistical model for decaying quantum systems
(e.g. photo-dissociation or -ionization). It takes the interference between
direct and indirect decay processes explicitely into account. The resulting
expressions for the partial decay amplitudes and the corresponding cross
sections may be considered a many-channel many-resonance generalization of
Fano's original work on resonance lineshapes [Phys. Rev 124, 1866 (1961)].
A statistical (random matrix) model is then introduced. It allows to describe
chaotic scattering systems with tunable couplings to the decay channels. We
focus on the autocorrelation function of the total (photo) cross section, and
we find that it depends on the same combination of parameters, as the
Fano-parameter distribution. These combinations are statistical variants of the
one-channel Fano parameter. It is thus possible to study Fano interference
(i.e. the interference between direct and indirect decay paths) on the basis of
the autocorrelation function, and thereby in the regime of overlapping
resonances. It allows us, to study the Fano interference in the limit of
strongly overlapping resonances, where we find a persisting effect on the level
of the weak localization correction.Comment: 16 pages, 2 figure
Statistics of S-matrix poles in Few-Channel Chaotic Scattering: Crossover from Isolated to Overlapping Resonances
We derive the explicit expression for the distribution of resonance widths in
a chaotic quantum system coupled to continua via M equivalent open channels. It
describes a crossover from the distribution (regime of isolated
resonances) to a broad power-like distribution typical for the regime of
overlapping resonances. The first moment is found to reproduce exactly the
Moldauer-Simonius relation between the mean resonance width and the
transmission coefficient. This fact may serve as another manifestation of
equivalence between the spectral and the ensemble averaging.Comment: 4 two-column pages, RevTex. text is slightly modified; some misprints
are correcte
Semiclassical Theory for Decay and Fragmentation Processes in Chaotic Quantum Systems
We consider quantum decay and photofragmentation processes in open chaotic
systems in the semiclassical limit. We devise a semiclassical approach which
allows us to consistently calculate quantum corrections to the classical decay
to high order in an expansion in the inverse Heisenberg time. We present
results for systems with and without time reversal symmetry and also for the
symplectic case, as well as extending recent results to non-localized initial
states. We further analyze related photodissociation and photoionization
phenomena and semiclassically compute cross-section correlations, including
their Ehrenfest time dependence.Comment: 17 pages, 5 figure
Statistics of photodissociation spectra: nonuniversal properties
We consider the two-point correlation function of the photodissociation cross
section in molecules where the fragmentation process is indirect, passing
through resonances above the dissociation threshold. In the limit of
overlapping resonances, a formula is derived, relating this correlation
function to the behavior of the corresponding classical system. It is shown
that nonuniversal features of the two-point correlation function may have
significant experimental manifestations.Comment: 4 pages, 1 figur
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