6,158 research outputs found
The Smart Stage: Designing 3D interaction metaphors for immersive and ubiquitous music systems
This conceptual paper describes a work in
progress in the process of design and implementation of the
Smart Stage, an interactive music system prototype for
collaborative musical creativity in immersive and ubiquitous
environments. This system is intended to have a low entry
barrier, thus more forgiving to users with lesser experience or
knowledge in music, and it is designed with affordances to
support intuitive progress in improvisational performance in a
collaborative setting. We present a preliminary technical
overview of the system and a first case study of a 3D
interaction metaphor for granular synthesis, developed for this
environment.Innovation Agency (Agência de Inovação, ADI, Portugal) and Quadro de Referência Estratégico Nacional
(QREN, Portugal): VisualYzARt: Visual programming framework for augmented reality and ubiquitous natural user interfaces (QREN-ADI ref: 23201) and COMPETE - Programa Operacional Factores de Competitividade (POFC
Probabilistic clustering of interval data
In this paper we address the problem of clustering interval data, adopting a model-based approach. To this purpose, parametric models for interval-valued variables are used which consider configurations for the variance-covariance matrix that take the nature of the interval data directly into account. Results, both on synthetic and empirical data, clearly show the well-founding of the proposed approach. The method succeeds in finding parsimonious heterocedastic models which is a critical feature in many applications. Furthermore, the analysis of the different data sets made clear the need to explicitly consider the intrinsic variability present in interval data.info:eu-repo/semantics/publishedVersio
BEC-BCS crossover in a cold and magnetized two color NJL model
The BEC-BCS crossover for a NJL model with diquark interactions is studied in
the presence of an external magnetic field. Particular attention is paid to
different regularization schemes used in the literature. A thorough comparison
of results is performed for the case of a cold and magnetized two-color NJL
model. According to our results, the critical chemical potential for the BEC
transition exhibits a clear inverse magnetic catalysis effect for magnetic
fields in the range . As for the BEC-BCS
crossover, the corresponding critical chemical potential is very weakly
sensitive to magnetic fields up to , showing a much smaller
inverse magnetic catalysis as compared to the BEC transition, and displays a
strong magnetic catalysis from this point on.Comment: 15 pages, 8 figures; v2 PRD versio
Liquid Mixtures Involving Hydrogenated and Fluorinated Chains: (p, ρ, T, x) Surface of (Ethanol + 2,2,2-Trifluoroethanol), Experimental and Simulation
The effect of mixing hydrogenated and fluorinated molecules that
simultaneously interact through strong hydrogen bonding was investigated: (ethanol +
2,2,2-trifluoroethanol) binary mixtures were studied both experimentally and by
computer simulation. This mixture displays a very complex behavior when compared
with mixtures of hydrogenated alcohols and mixtures of alkanes and perfluoroalkanes.
The excess volumes are large and positive (unlike those of mixtures of hydrogenated
alchools), while the excess enthalpies are large and negative (contrasting with those of
mixtures of alkanes and perfluoroalkanes). In this work, the liquid density of the
mixtures was measured as a function of composition, at several temperatures from
278.15 to 353.15 K and from atmospheric pressure up to 70 MPa. The corresponding
excess molar volumes, compressibilities, and expansivities were calculated over the
whole (p, ρ, T, x) surface. In order to obtain molecular level insight, the behavior of the mixture was also studied by molecular
dynamics simulation, using the OPLS-AA force field. The combined analysis of the experimental and simulation results indicates
that the peculiar phase behavior of this system stems from a balance between the weak dispersion forces between the
hydrogenated and fluorinated groups and a preferential hydrogen bond between ethanol and 2,2,2-trifluoroethanol. Additionally,
it was observed that a 25% reduction of the F−H dispersive interaction in the simulations brings agreement between the
experimental and simulated excess enthalpy but produces no effect in the excess volumes. This reveals that the main reason
causing the volume increase in these systems is not entirely related to the weak dispersive interactions, as it is usually assumed,
and should thus be connected to the repulsive part of the intermolecular potential
Development of a monitoring system for electrical energy consumption and power quality analysis
This paper presents the development of a monitoring system for electrical energy consumption and power quality analysis, also known as power quality analyser (PQA). The internal architecture of the developed monitoring system is described in detail along the paper, highlighting the signal conditioning circuit and analogue to digital conversion (ADC) stage, the advanced RISC machine (ARM) processor, and the digital signal processor (DSP), which are used, respectively, for data acquisition, data communication and power quality calculations. This paper also describes the software developed for a Raspberry Pi, which receives the processed information from the ARM processor and presents it in real-time using a touch screen user-friendly interface. Among all the available features of the developed system, the paper presents the most relevant experimental results obtained with linear and nonlinear loads, showing the main functionalities of the different menus available in the developed user interface, mainly the menus “Scope”, “Harmonics” and “Data”.This work is supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941.info:eu-repo/semantics/publishedVersio
Particles’ distribution enhancing in aluminum-based composites produced by upward friction stir processing
Funding Information: Open access funding provided by FCT|FCCN (b-on). CV and TGS acknowledge Fundação para a Ciência e a Tecnologia (FCT-MCTES) for its financial support via projects UIDB/00667/2020 and UIDP/00667/2020 (UNIDEMI). PMF also acknowledges FCT-MCTES for its financial support via the PhD scholarship UI/BD/151055/2021. PLI would like to acknowledge FCT-MCTES for its financial support via the PhD scholarship FCT-SFRH /BD/146885/2019. RJCS acknowledges national funds from FCT-MCTES, in the scope of the project UIDB/50025/2020–2023 of the CENIMAT/i3N. Publisher Copyright: © 2023, The Author(s).A new variant of friction stir processing named upward friction stir processing (UFSP) is a promising approach to control particles’ distribution and promote a more uniform distribution over a larger processed area. This variant involves using two sheets with functional particles between them to produce metallic composites. A spacer is used to ensure the desired quantity and uniform distribution of the particles and prevent sputtering. This technique promotes an upward flow to introduce more particles with a uniform distribution in the processed volume, avoiding discrete holes or grooves. This study involved enhancing the particles’ distribution by varying process parameters. The resulting trial with the best particles’ distribution was characterized by means of light microscopy, eddy current testing, microhardness mapping, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The study revealed that UFSP can improve the particles’ distribution in the stir zone of metallic composites, especially when multi-passes are performed towards the retreating side of the plates. The process parameters that produced an improvement in particles’ distribution were six passes with an offset of 1 mm towards the retreating side, the tool rotation and processing speed of 900 rev/min, and 180 mm/min, respectively, and a spacer’s thickness of 0.5 mm. The resulting hardness and electrical conductivity profiles show that the UFSP technique can significantly affect material’s properties, including mechanical strength, particularly when processing with tool offset towards the retreating side. Furthermore, the hardness increased by about 22% in composites produced with the addition of reinforcement particles. However, for some aluminum alloys, the properties decreased under such conditions. These findings highlight the potential of UFSP for producing functionalized materials with tailored properties, while also underscoring the importance of careful parameters selection to optimize the material´s performance. Graphical Abstract: [Figure not available: see fulltext.].publishersversioninpres
NMR assignment of the apo-form of a Desulfovibrio gigas protein containing a novel Mo–Cu cluster
Biomol NMR Assign (2007) 1:81–83
DOI 10.1007/s12104-007-9022-3We report the 98% assignment of the apo-form
of an orange protein, containing a novel Mo–Cu cluster isolated from Desulfovibrio gigas. This protein presents a region where backbone amide protons exchange fast with bulk solvent becoming undetectable. These residues were assigned using 13C-detection experiments
Surveillance of non-indigenous invertebrate species through DNA metabarcoding in recreational marinas in the North and Center of Portugal
DNA metabarcoding has been widely used in biodiversity assessments as a complement to
traditional morphology-based techniques. This technique is useful for the early detection
and surveillance of non-indigenous species (NIS) in aquatic ecosystems. When introduced
to new locations, NIS can establish, and become invasive, which may cause severe
alterations to native ecosystems and biodiversity. As most introductions in coastal
ecosystems occur by transport in ships (through ballast waters discharges and biofouling),
ports and marinas are priority hubs for the early detection of NIS. The aim of this study was
to survey marine invertebrate NIS in four marinas in the north and center of Portugal using
(e)DNA metabarcoding and different sampling methodologies.
We sampled four marinas in three locations in Portugal spanning a distance of ca. 150 km:
one in Viana do Castelo (VC), one in Porto (L), inside the port of Leixões, and two in Aveiro
(Av1: Costa Nova and Av2: Oudinot). Viana do Castelo, Porto, and Oudinot marinas are
more sheltered, located near the coast, with a lower current flow, while Costa Nova marina
is located inside a channel, more exposed to the passage of ships and to a higher current
flow. Samples were taken of the organisms colonizing the marinas’ hard substrates (e.g. pontoons, buoys, ropes), as well as from water, for environmental DNA (eDNA) analysis,
and zooplankton, collected using a 55-µm mesh net. We used two molecular markers: the
mitochondrial cytochrome c oxidase gene (COI) and the small subunit ribosomal RNA gene
(18S) to produce amplicon libraries for each sample, which were high throughput
sequenced in an Illumina MiSeq platform. mBRAVE and SILVAngs were then used to
process the sequence data and to generate species-level assignments for COI and 18S
data, respectively.
A total of 23 NIS was detected in this study: 13 using each molecular marker. Only 3 NIS
were detected using both markers. The highest number of NIS was detected in the Av1
marina with COI (11), whereas in the other marinas this number ranged from 5-9 NIS
depending on the molecular marker. Six NIS were common to all the marinas, amongst
which Amphibalanus amphitrite and Amphibalanus eburneus , two invasive barnacle
species and Eriocheir sinensis, the Chinese mitten crab, a very well-known species with
invasive behavior that causes severe ecological and economic damages. Fifty percent of
NIS belonged to the phyla Arthropoda: Crustacea and Chordata: Ascidiacea. The sampling
method that registered the highest number of NIS (9) was the eDNA from water in Av1,
using COI. Overall, 18S detected approximately 1,6 times higher numbers of OTUs
(237-267), phyla (16-21) and species (179-210) than COI, and only 5-6% of species were
detected using both markers. Regarding the type of sampling method, the zooplankton
samples retrieved the highest number of phyla (20 in VC; COI: 12 and 18S: 20) and more
species (40 to 155; COI: 90 and 18S: 155), namely from Mollusca and Annelida. Between
the three methods, there were only 21 (COI) to 28% (18S) of shared species. Crustacea
dominated most samples collected from hard substrates. As for marinas, VC had the
highest number of recovered OTUs (267), phyla (21) and species (210), when analyzed
with the 18S marker, and the lowest number of OTUs (94) and species (86) was recovered
in Av1 with COI. Coincidently, this was also the marina with the highest number of NIS
probably due to its more exposed location.
These results show the efficiency of NIS detection using (e)DNA metabarcoding but reveal
the need to employ different molecular markers and sampling methodologies to guarantee
a more comprehensive surveillance and detection of NIS in these environmentsNIS-DNA: Early detection and monitoring of non-indigenous species (NIS) in coastal
ecosystems based on high-throughput sequencing tools (PTDC/BIA-BMA/29754/2017).
Ana S. Lavrador was supported by grant UI/BD/150871/202
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