421 research outputs found
Signal feature extraction for sewing analysis using non-linear tecniques
Comunicação apresentada no International Symposium on Industrial Electronics, Rio de Janeiro, Brasil, 9 - 11 Junho 2003.This paper describes the measurement of a proc-ess variable in industrial sewing machines using a piezoelectric sensing system and non-linear filtering and processing tech-niques. The objective is to obtain a measure of the needle pene-tration and withdrawal forces in a fabric, which can be used to detect faulty processing conditions causing second-rate quality products. Aimed for future real-time applications, currently the measurement process has been optimised for laboratory use. It provides the means for experimentation leading to the development of further processing techniques able to detect fault conditions automatically, a completely innovative indus-trial application.
The signal is acquired by a piezoelectric sensor introduced in the needle support bar. With this set-up, the sensor provides not only the forces related to needle-fabric interaction, but also other, undesired components, that are reduced with specifi-cally developed techniques. This paper presents the advantages and drawbacks of the measurement set-up and describes the optimization of the complex processing techniques used to ex-tract the relevant information from the signals.Fundação para a Ciência e Tecnologia - POSI/SRI/38944/2001
Convergence insufficiency and accommodative insufficiency in children
Purpose: Convergence and accommodative insufficiency represent the main cause of complaints during close
visual work and can reduce visual performance and comfort. Knowing their prevalence among schoolchildren is
fundamental to define strategies for action. The purpose of this study was to estimate the frequency of these
conditions in children in 5th and 6th school years in inland Portugal and to assess the impact that each visual
condition has on their quality of life, based on the level of visual symptoms.
Methods: a cross-sectional study was carried out with children enrolled in the 5th and 6th school years. 372
children (192 girls) were assessed, with average ages of 10.9 ± 0.9 years. Refractive error and binocular vision
assessment, integrating accommodative parameters, were used to analyse the visual condition. Symptoms were
quantified using the Portuguese version of the CISS (Convergence Insufficiency Symptom Survey).
Results: The prevalence of definite Convergence Insufficiency (CI) in the children assessed was 2%. A prevalence
of 6,8% could be considered if clinically significant CI (high suspect and definite categories) cases are accounted.
In relation to Accommodative Insufficiency (AI), a frequency rate of 10% was recorded, with 3% of the evaluated
children presenting AI and CI simultaneously. The symptoms score was higher in AI than in CI.
Conclusions: A frequency of approximately 10% was found for each one of the visual syndromes, and it was
verified that visual discomfort is common among teenagers who carry these conditions. In cases of asthenopia,
such as headaches and loss of concentration, associated with near vision activities, there is a requirement to
evaluate the quality of binocular vision.info:eu-repo/semantics/publishedVersio
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
Age, growth and reproduction of the Axilary Seabream, "Pagellus acarne" (Risso, 1827), from the South coast of Portugal
Axillary seabream, Pagellus acarne, caught by longlines in the Algarve (Southern Portugal), were
sampled between August 1995 and August 1996. Age was studied by counting growth increments on otoliths
and the estimated von Bertalanffy parameters were Linf = 28.82 cm, K = 0.29 year-1 and t0 = -1.47 year for
males and Linf = 32.30 cm, K = 0.18 year-1 and t0 = -2.56 year for females. Evidence of the annual periodicity of
the deposition of increments was found by marginal increment analyses. Macroscopic analysis of the
gonads and the gonad somatic index showed that reproduction occurred over an extensive period of
time, from May to November. Lengths at first maturity were 18.10 and 17.60 cm for males and females,
respectively. This species was characterized as being a protandric hermaphrodite.info:eu-repo/semantics/publishedVersio
Methodology for assessing the individual role of fish, oyster, phytoplankton and macroalgae in the ecology of integrated production in earthen ponds
Production costs in extensive and semi-intensive fish culture in earthen ponds are often too high to offer sustainable economic activity due to the low productivity of these systems. The right combination of commercial finfish species with inorganic (primary producers) and organic extractive (bivalves) species in Integrated MultiTrophic Aquaculture (IMTA) create a balanced system with higher profitability and risk reduction. To achieve this, it is crucial to understand the role of each functional groups within the system what we did by comparing three different IMTA production three different IMTA production treatments with distinct combinations of trophic levels: •fish, filter feeders, phytoplankton and macroalgae,•fish, filter feeders and phytoplankton•fish, phytoplankton and macroalgae Each treatment was carried out in two similar ponds under semi-intensive conditions and flow through system, in a total of 6 earthen ponds of 500 m2 surface and depth of 1.5 m. Results showed that the presence of oysters in the ponds enhanced water quality by decreasing turbidity and by controlling phytoplankton which led to regulation of dissolved oxygen levels. The enhanced water quality in these systems lead to improved fish performance and higher biomass production contributing to greater profitability. The combination of fish, oyster, phytoplankton and macroalgae was particularly good providing much more fish supply compared with the other two treatments. •Oysters enhanced water quality in the ponds by decreasing turbidity and controlling phytoplankton which regulated the dissolved oxygen levels.•The enhanced water quality in systems with oysters improve fish performance resulting in higher biomass production and greater profitability.•The combination of fish, oyster, phytoplankton and macroalgae was particularly good providing much more fish supply compared with the other two treatments.Funding Agency
Fundacao para a Ciencia e a Tecnologia (FCT)
COFASP/0003/2015
SFRH/BD/118601/2016
Project DIVERSIAQUA
Mar2020 16-02-01-FMP-0066
project Algared+
Poctep 0055_ALGARED_PLUS_5_E
UID/Multi/04326/2019info:eu-repo/semantics/publishedVersio
Revisiting niche fundamentals with Tukey depth
1. The first attempts to describe species ecological niches were simple geometric procedures that depict the niche boundaries directly from environmental data. The convex hull was one of such procedures, popular for its simplicity, clear ecological rational and precise definition of the niche. However, it lacked the ability to differentiate areas of the niche with different probabilities of occurrence according to environmental suitability. 2. We incorporate the Tukey depth, a mathematical tool to measure the centrality of a point within a cloud of points on a multidimensional space, in the convex hull approach to (i) propose a new procedure (CH-Tukey) to estimate species’ environmental suitability, and (ii) estimate niche overlap coherently. In addition to a clear ecological rational and simplicity the CHTukey procedure has a number of attractive features: use of presence-only data; independence from background data; invariance to scale; robustness to outliers; and the decomposition of the niche into a finite number of isosuitability levels, permitting the computation of consistent overlap indices. We illustrate the use of CH-Tukey, using occurrence data of the main Quercus species and subspecies from Western Mediterranean Europe, comparing its outputs with BIOCLIM and MAXENT. 3. Results showed distinct niche geometries among the different approaches. BIOCLIM produced rectilinear niches reflecting the assumption that ecological variables are independent in their action on the species. CHTukey, relaxing this assumption, adjusts niche outer boundary and the inner suitability levels to the known occurrences. MAXENT produced unbounded niche geometries, showing abrupt shifts in the species response to the environmental variables. 4. The niche predictions obtained with geometric approaches, BIOCLIM and CH Tukey, are simpler but better aligned with Hutchinson’s niche concept than those obtained with MAXENT, this latter showing ecologically implausible relationships with the environmental variables. CH-Tukey and the related overlap measures provide an adequate tool to explore niche properties and species-environment relationships
Cytotoxic plant extracts towards insect cells: bioactivity and nanoencapsulation studies for application as biopesticides
The potential of plant extracts as bioinsecticides has been described as a promising field of agricultural development. In this work, the extracts of Punica granatum (pomegranate), Phytolacca americana (American pokeweed), Glandora prostrata (shrubby gromwell), Ulex europaeus (gorce), Tagetes patula (French marigold), Camellia japonica red (camellia), Ruta graveolens (rue or herb-of-grace) were obtained, purified, and their activity against Spodoptera frugiperda (Sf9) insect cells was investigated. From the pool of over twenty extracts obtained, comprising different polarities and vegetable materials, less polar samples were shown to be more toxic towards the insect cell line Sf9. Among these, a dichloromethane extract of R. graveolens was capable of causing a loss of viability of over 50%, exceeding the effect of the commercial insecticide chlorpyrifos. This extract elicited chromatin condensation and the fragmentation in treated cells. Nanoencapsulation assays of the cytotoxic plant extracts in soybean liposomes and chitosan nanostructures were carried out. The nanosystems exhibited sizes lower or around 200 nm, low polydispersity, and generally high encapsulation efficiencies. Release assays showed that chitosan nanoemulsions provide a fast and total extract release, while liposome-based systems are suitable for a more delayed release. These results represent a proof-of-concept for the future development of bioinsecticide nanoformulations based on the cytotoxic plant extracts.This research was funded by COMPETE 2020 program, co-financed by the FEDER and the European Union, PTDC/ASP-AGR/30154/2017 (POCI-01-0145-FEDER-030154). Foundation for Science and Technology (FCT, Portugal), and FEDER-COMPETE-QREN-EU funded research centers CQ-UM(UIDB/00686/2020), CF-UM-UP (UIDB/04650/2020) and REQUIMTE (UIDB/50006/2020)
Personalized dynamic phantom of the right and left ventricles based on patient-specific anatomy for echocardiography studies — Preliminary results
Dynamic phantoms of the heart are becoming a reality, with their use spread across both medical and research fields. Their purpose is to mimic the cardiac anatomy, as well as its motion. This work aims to create a dynamic, ultrasound-compatible, realistic and flexible phantom of the left and right ventricles, with application in the diagnosis, planning, treatment and training in the cardiovascular field for studies using echocardiography. Here, we focus on its design and production with polyvinyl alcohol cryogel (PVA-C), to be assembled with a pump and an electromechanical (E/M) system in a water tank. Based on a patient-specific anatomical model and produced using a 3D printing technique and molding, the PVA-C phantom mimics the ventricles' natural anatomy and material properties, while the pump and E/M systems mimic the natural movements and pressures. The PVA-C phantom was assessed by imaging and measuring it using a four-dimensional ultrasound machine. The PVA-C phantom demonstrated to be a versatile option to produce patient-specific biventricular models, preserving their shape after manufacturing and presenting good echogenic properties. Both chambers were clearly seen in the ultrasound images, together with the interventricular septum and the myocardial wall. Automated left ventricle measures revealed a decrease of its volume with regard to the designed model (98 ml to 74 ml). Overall, the preliminary results are satisfactory and encourage its use for the abovementioned purposesFEDER funds through the Competitiveness
Factors Operational Programme
(COMPETE), and by National funds through the
Foundation for Science and Technology (FCT) under the project POCI
-01-0145-FEDER-007038 and EXPL/BBB-BMD/2473/2013, and by the projects NORTE-01-0145-FEDER-000013 and NORTE-01-0145-FEDER-024300, supported by the
NORTE 2020, under the Portugal 2020 Partnership Agreement, through the
European Regional Development Fund (FEDER). J. Gomes-Fonseca, P. Morais, S.
QueirĂłs, and F. Veloso were funded by FCT under the Ph.D. grants
PD/BDE/113597/2015, SFRH/BD/95438/2013, SFRH/BD/93443/2013, and
SFRH/BD/131545/2017info:eu-repo/semantics/publishedVersio
Overview of the work carried out in CleanAtlantic on improving marine litter monitoring: • WP 5.2.1. – Improving methods for marine litter monitoring in the Atlantic Area: seabed, floating and coastal litter • WP 5.2.2. – New tools for the monitoring of marine litter
This report collates the main results delivered in the frame of the CleanAtlantic project, Work package 5.2.
Monitoring the presence of marine litter in the marine environment. With this purpose, an overview of new
and improved marine litter monitoring methods for seabed, water surface and coastal compartments in the
Atlantic Area is presented. Main findings, gaps on monitoring and research as well as potential
improvements and recommendations are highlighted. For some of the topics addressed partners produced fully-dedicated reports. In these cases, links to the original reports are included in the reference section for further information
Improved X-ray detection and particle identification with avalanche photodiodes
Avalanche photodiodes are commonly used as detectors for low energy x-rays.
In this work we report on a fitting technique used to account for different
detector responses resulting from photo absorption in the various APD layers.
The use of this technique results in an improvement of the energy resolution at
8.2 keV by up to a factor of 2, and corrects the timing information by up to 25
ns to account for space dependent electron drift time. In addition, this
waveform analysis is used for particle identification, e.g. to distinguish
between x-rays and MeV electrons in our experiment.Comment: 6 pages, 6 figure
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