63 research outputs found
Opto-PCB: Three demonstrators for optical interconnections
We report on a research project targeting optical waveguide integrated PCBs conducted within the European FP6
Network of Excellence on Micro-Optics NEMO. For three identified feature requests we have built three specific demonstrators
respectively addressing the integration of active components, the fabrication of peripheral fibre ribbons and the integration of
multiple layers of waveguides on the board
Nonlinear Time Series Analysis of Sunspot Data
This paper deals with the analysis of sunspot number time series using the
Hurst exponent. We use the rescaled range (R/S) analysis to estimate the Hurst
exponent for 259-year and 11360-year sunspot data. The results show a varying
degree of persistence over shorter and longer time scales corresponding to
distinct values of the Hurst exponent. We explain the presence of these
multiple Hurst exponents by their resemblance to the deterministic chaotic
attractors having multiple centers of rotation.Comment: 10 pages, 6 figures, accepted for publication in Solar Physics,
journal style corrections done in this versio
Silicon oxycarbide glass for the immobilisation of irradiated graphite waste
© 2015 Elsevier B.V. Silicon oxycarbide glass has been investigated as a potential immobilisation medium for irradiated graphite waste from nuclear power generation. The glass was synthesised via sol-gel techniques using alkoxysilane precursors. Attempts to produce a wasteform via conventional sintering were unsuccessful, but dense wasteforms were achieved by spark plasma sintering (SPS). Microstructural investigations showed that the addition of graphite to the glass did not alter the structure of the matrix; no reaction between the graphite and the glass matrix was observed. Silicon oxycarbide glass is a viable candidate for encapsulation of graphite waste prior to disposal
Cucurbita plants: From farm to industry
The Cucurbita genus, a member of Cucurbitaceae family, also known as cucurbits, is native to the Americas. Genus members, like Cucurbita pepo and Cucurbita maxima, have been used for centuries in folk medicine for treating gastrointestinal diseases and intestinal parasites. These pharmacological effects are mainly attributed to their phytochemical composition. Indeed, Cucurbita species are a natural source of carotenoids, tocopherols, phenols, terpenoids, saponins, sterols, fatty acids, functional carbohydrates, and polysaccharides, that beyond exerting remarkable biological effects, have also been increasingly exploited for biotechnological applications. In this article, we specifically cover the habitat, cultivation, phytochemical composition, and food preservative abilities of Cucurbita plants.This work was supported by CONICYT PIA/APOYO CCTE AFB170007. N. Martins would like to thank the Portuguese Foundation for Science and Technology (FCT-Portugal) for the Strategic project ref. UID/BIM/04293/2013 and “NORTE2020-Northern Regional Operational Program” (NORTE-01-0145-FEDER-000012)
Canonical horizontal visibility graphs are uniquely determined by their degree sequence
Horizontal visibility graphs (HVGs) are graphs constructed in correspondence
with number sequences that have been introduced and explored recently in the
context of graph-theoretical time series analysis. In most of the cases simple
measures based on the degree sequence (or functionals of these such as
entropies over degree and joint degree distributions) appear to be highly
informative features for automatic classification and provide nontrivial
information on the associated dynam- ical process, working even better than
more sophisticated topological metrics. It is thus an open question why these
seemingly simple measures capture so much information. Here we prove that,
under suitable conditions, there exist a bijection between the adjacency matrix
of an HVG and its degree sequence, and we give an explicit construction of such
bijection. As a consequence, under these conditions HVGs are unigraphs and the
degree sequence fully encapsulates all the information of these graphs, thereby
giving a plausible reason for its apparently unreasonable effectiveness
A combinatorial framework to quantify peak/pit asymmetries in complex dynamics
LL’s acknowledges funding from an EPSRC Early Career Fellowship EP/P01660X/1
Does AI-technology-based indoor environmental quality impact occupants’ psychological, physiological health, and productivity?
Over the past century, because of increased global travel, there high growth in the travel and tourism sector. But the outbreak of an ongoing pandemic has changed this scenario, which has put tremendous focus on the Indoor Environmental Quality (IEQ) embedded with the application of technologies, especially artificial intelligence (AI). This study aims to investigate the effect of AI-technology-based IEQ in the hospitality industry on occupants’ productivity through their psychological and physiological health. Drawing from Job demand - resource theory and Nudging philosophy, we formulated the hypoth-esis and conceptual model, which was empirically tested by structural equation model-ing (SEM). The results show that AI-technology-based IEQ is statistically significant in people’s behavioral change, which reflects on occupants’ health and productivity. Notably, AI-technology-based IEQ of the hospitality industry had a greater influence on occupants’ productivity, followed by their psychological and physiological health
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