41 research outputs found
Deploying the ICT architecture of a residential demand response pilot
The Flemish project Linear was a large scale residential demand response pilot that aims to validate innovative smart grid technology building on the rollout of information and communication technologies in the power grid. For this pilot a scalable, reliable and interoperable ICT infrastructure was set up, interconnecting 240 residential power grid customers with the backend systems of energy service providers (ESPs), flexibility aggregators, distribution system operators (DSOs) and balancing responsible parties (BRPs). On top of this architecture several business cases were rolled out, which require the sharing of metering data and flexibility information, and demand response algorithms for the balancing of renewable energy and the mitigation of voltage and power issues in distribution grids. The goal of the pilot is the assessment of the technical and economical feasibility of residential demand response in real life, and of the interaction with the end-consumer.
In this paper we focus on the practical experiences and lessons learnt during the deployment of the ICT technology for the pilot. This includes the real-time gathering of measurement data and real-time control of a wide range of smart appliances in the homes of the participants. We identified a number of critical issues that need to be addressed for a future full-scale roll-out: (i) reliable in-house communication, (ii) interoperability of appliances, measurement equipment, backend systems, and business cases, and (iii) sufficient backend processing power for real-time analysis and control
Modeling Structural Colors from Disordered One-Component Colloidal Nanoparticle-based Supraballs using Combined Experimental and Simulation Techniques
Bright, saturated structural colors in birds have inspired synthesis of
self-assembled, disordered arrays of assembled nanoparticles with varied
particle spacings and refractive indices. However, predicting colors of
assembled nanoparticles, and thereby guiding their synthesis, remains
challenging due to the effects of multiple scattering and strong absorption.
Here, we use a computational approach to first reconstruct the nanoparticles'
assembled structures from small-angle scattering measurements and then input
the reconstructed structures to a finite-difference time-domain method to
predict their color and reflectance. This computational approach is
successfully validated by comparing its predictions against experimentally
measured reflectance and provides a pathway for reverse engineering colloidal
assemblies with desired optical and photothermal properties.Comment: 14 pages, 3 figures, 1 ToC figur
Structural Color Production in Melanin-based Disordered Colloidal Nanoparticle Assemblies in Spherical Confinement
Melanin is a ubiquitous natural pigment that exhibits broadband absorption
and high refractive index. Despite its widespread use in structural color
production, how the absorbing material, melanin, affects the generated color is
unknown. Using a combined molecular dynamics and finite-difference time-domain
computational approach, this paper investigates structural color generation in
one-component melanin nanoparticle-based supra-assemblies (called supraballs)
as well as binary mixtures of melanin and silica (non-absorbing)
nanoparticle-based supraballs. Experimentally produced one-component melanin
and one-component silica supraballs, with thoroughly characterized primary
particle characteristics using neutron scattering, produce reflectance profiles
similar to the computational analogues, confirming that the computational
approach correctly simulates both absorption and multiple scattering from the
self-assembled nanoparticles. These combined approaches demonstrate that
melanin's broadband absorption increases the primary reflectance peak
wavelength, increases saturation, and decreases lightness factor. In addition,
the dispersity of nanoparticle size more strongly influences the optical
properties of supraballs than packing fraction, as evidenced by production of a
larger range of colors when size dispersity is varied versus packing fraction.
For binary melanin and silica supraballs, the chemistry-based stratification
allows for more diverse color generation and finer saturation tuning than does
the degree of mixing/demixing between the two chemistries.Comment: 40 pages, Figure
Mechanism of Structural Colors in Binary Mixtures of Nanoparticle-based Supraballs
Inspired by structural colors in avian species, various synthetic strategies
have been developed to produce non-iridescent, saturated colors using
nanoparticle assemblies. Mixtures of nanoparticles varying in particle
chemistry (or complex refractive indices) and particle size have additional
emergent properties that impact the color produced. For such complex
multi-component systems, an understanding of assembled structure along with a
robust optical modeling tool can empower scientists to perform intensive
structure-color relationship studies and fabricate designer materials with
tailored color. Here, we demonstrate how we can reconstruct the assembled
structure from small-angle scattering measurements using the computational
reverse-engineering analysis for scattering experiments (CREASE) method and
then use the reconstructed structure in finite-difference time-domain (FDTD)
calculations to predict color. We successfully, quantitatively predict
experimentally observed color in mixtures containing strongly absorbing melanin
nanoparticles and demonstrate the influence of a single layer of segregated
nanoparticles on color produced. The versatile computational approach presented
in this work is useful for engineering synthetic materials with desired colors
without laborious trial and error experiments.Comment: 23 Pages, 5 Figures, 1 ToC Figur
Software engineering techniques for the development of systems of systems
This paper investigates how existing software engineering techniques can be employed, adapted and integrated for the development of systems of systems. Starting from existing system-of-systems (SoS) studies, we identify computing paradigms and techniques that have the potential to help address the challenges associated with SoS development, and propose an SoS development framework that combines these techniques in a novel way. This framework addresses the development of a class of IT systems of systems characterised by high variability in the types of interactions between their component systems, and by relatively small numbers of such interactions. We describe how the framework supports the dynamic, automated generation of the system interfaces required to achieve these interactions, and present a case study illustrating the development of a data-centre SoS using the new framework
Spiders do not escape reproductive manipulations by Wolbachia
<p>Abstract</p> <p>Background</p> <p>Maternally inherited bacteria that reside obligatorily or facultatively in arthropods can increase their prevalence in the population by altering their hosts' reproduction. Such reproductive manipulations have been reported from the major arthropod groups such as insects (in particular hymenopterans, butterflies, dipterans and beetles), crustaceans (isopods) and mites. Despite the observation that endosymbiont bacteria are frequently encountered in spiders and that the sex ratio of particular spider species is strongly female biased, a direct relationship between bacterial infection and sex ratio variation has not yet been demonstrated for this arthropod order.</p> <p>Results</p> <p>Females of the dwarf spider <it>Oedothorax gibbosus </it>exhibit considerable variation in the sex ratio of their clutches and were infected with at least three different endosymbiont bacteria capable of altering host reproduction i.e. <it>Wolbachia</it>, <it>Rickettsia </it>and <it>Cardinium</it>. Breeding experiments show that sex ratio variation in this species is primarily maternally inherited and that removal of the bacteria by antibiotics restores an unbiased sex ratio. Moreover, clutches of females infected with <it>Wolbachia </it>were significantly female biased while uninfected females showed an even sex ratio. As female biased clutches were of significantly smaller size compared to non-distorted clutches, killing of male embryos appears to be the most likely manipulative effect.</p> <p>Conclusions</p> <p>This represents to our knowledge the first direct evidence that endosymbiont bacteria, and in particular <it>Wolbachia</it>, might induce sex ratio variation in spiders. These findings are pivotal to further understand the diversity of reproductive phenotypes observed in this arthropod order.</p