12,801 research outputs found
Flat-plate solar array project. Volume 5: Process development
The goal of the Process Development Area, as part of the Flat-Plate Solar Array (FSA) Project, was to develop and demonstrate solar cell fabrication and module assembly process technologies required to meet the cost, lifetime, production capacity, and performance goals of the FSA Project. R&D efforts expended by Government, Industry, and Universities in developing processes capable of meeting the projects goals during volume production conditions are summarized. The cost goals allocated for processing were demonstrated by small volume quantities that were extrapolated by cost analysis to large volume production. To provide proper focus and coverage of the process development effort, four separate technology sections are discussed: surface preparation, junction formation, metallization, and module assembly
Finite-Element Simulations of Light Propagation through Circular Subwavelength Apertures
Light transmission through circular subwavelength apertures in metallic films
with surrounding nanostructures is investigated numerically. Numerical results
are obtained with a frequency-domain finite-element method. Convergence of the
obtained observables to very low levels of numerical error is demonstrated.
Very good agreement to experimental results from the literature is reached, and
the utility of the method is demonstrated in the investigation of the influence
of geometrical parameters on enhanced transmission through the apertures
Responses of the EU feed and livestock system to shocks in trade and production
Dit rapport gaat in op de mogelijke effecten van meervoudige en/of langdurige calamiteiten die de beschikbaarheid van landbouwproducten verminderen op de Europese voedsel- en voersector in 2020
Collisional formation of massive exomoons of super-terrestrial exoplanets
Exomoons orbiting terrestrial or super-terrestrial exoplanets have not yet
been discovered; their possible existence and properties are therefore still an
unresolved question. Here we explore the collisional formation of exomoons
through giant planetary impacts. We make use of smooth particle hydrodynamical
(SPH) collision simulations and survey a large phase-space of
terrestrial/super-terrestrial planetary collisions. We characterize the
properties of such collisions, finding one rare case in which an exomoon forms
through a graze&capture scenario, in addition to a few graze&merge or hit&run
scenarios. Typically however, our collisions form massive circumplanetary
discs, for which we use follow-up N-body simulations in order to derive
lower-limit mass estimates for the ensuing exomoons. We investigate the mass,
long-term tidal-stability, composition and origin of material in both the discs
and the exomoons. Our giant-impact models often generate relatively iron-rich
moons, that form beyond the synchronous radius of the planet, and would thus
tidally evolve outward with stable orbits, rather than be destroyed. Our
results suggest that it is extremely difficult to collisionally form
currently-detectable exomoons orbiting super-terrestrial planets, through
single giant impacts. It might be possible to form massive, detectable exomoons
through several mergers of smaller exomoons, formed by multiple impacts,
however more studies are required in order to reach a conclusion. Given the
current observational initiatives, the search should focus primarily on more
massive planet categories. However, about a quarter of the exomoons predicted
by our models are approximately Mercury-mass or more, and are much more likely
to be detectable given a factor 2 improvement in the detection capability of
future instruments, providing further motivation for their development
Ability of new durum wheat pure lines to meet yield stability and quality requirements in low input and organic systems
Low-input production schemes adopted in organic or conventional farms require crop varieties that combine good product quality and high yield stability under non optimal environmental conditions (Gooding et al., 1999). These traits are not yet found among the durum wheat genotypes available in France. Consequently the cultivation of this crop is hardly successful in stockless organic farms in southern France, which are characterised by very low nitrogen resources. Some hopes emerged with the identification of new durum wheat pure lines with a high grain protein content in breeding experiments conducted near Montpellier in 2001 and 2002. The aim of the present work was to confirm and elucidate the origin of the enhanced protein performance of these new lines through a field experiment with nitrogen resources ranging from very low to sub-optimal levels
Fast simulation method for parameter reconstruction in optical metrology
A method for automatic computation of parameter derivatives of numerically
computed light scattering signals is demonstrated. The finite-element based
method is validated in a numerical convergence study, and it is applied to
investigate the sensitivity of a scatterometric setup with respect to
geometrical parameters of the scattering target. The method can significantly
improve numerical performance of design optimization, parameter reconstruction,
sensitivity analysis, and other applications
Three-dimensional quasi-Tonks gas in a harmonic trap
We analyze the macroscopic dynamics of a Bose gas in a harmonic trap with a
superimposed two-dimensional optical lattice, assuming a weak coupling between
different lattice sites. We consider the situation in which the local chemical
potential at each lattice site can be considered as that provided by the
Lieb-Liniger solution. Due to the weak coupling between sites and the form of
the chemical potential, the three-dimensional ground-state density profile and
the excitation spectrum acquire remarkable properties different from both 1D
and 3D gases. We call this system a quasi-Tonks gas. We discuss the range of
applicability of this regime, as well as realistic experimental situations
where it can be observed.Comment: 4 pages, 3 figures, misprints correcte
The Two-Screen Measurement Setup to Indirectly Measure Proton Beam Self-Modulation in AWAKE
The goal of the first phase of the AWAKE \cite{AWAKE1,AWAKE2} experiment at
CERN is to measure the self-modulation \cite{SMI} of the long SPS proton bunch into microbunches after traversing
of plasma with a plasma density of
. The two screen measurement setup
\cite{Turner2016} is a proton beam diagnostic that can indirectly prove the
successful development of the self-modulation of the proton beam by imaging
protons that got defocused by the transverse plasma wakefields after passing
through the plasma, at two locations downstream the end of the plasma. This
article describes the design and realization of the two screen measurement
setup integrated in the AWAKE experiment. We discuss the performance and
background response of the system based on measurements performed with an
unmodulated Gaussian SPS proton bunch during the AWAKE beam commissioning in
September and October 2016. We show that the system is fully commissioned and
adapted to eventually image the full profile of a self-modulated SPS proton
bunch in a single shot measurement during the first phase of the AWAKE
experiment.Comment: 5 pages 8 figure
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