3,164 research outputs found
Intelligent cutting-off of pipes and bars
Traditionally, automatic cutting-off machines, of
metallic pipes or bars, use a constant cutting velocity mode.
This mode of operation, constant cutting velocity combined
with different profiles of materials to be cut, exposes the cutting
saw to variable cutting forces. Therefore, the cutting off
machine is usually set for the worst expected conditions, otherwise
excessive wear of the saw and machine will occur. Further,
traditional cutting-off machines require the adjustment of
the position of a limit switch in order to automatically detect
when the cut of a piece has been completed. The aim of this
paper is to study the application of control algorithms to the
process of cutting-off metallic pipes or bars, with variable profiles,
implemented in an industrial cutting-off machine, commercially
available. The presented algorithms concern realtime
cutting control and automatic detection of the cutting end.
The algorithms are implemented in a low cost Programmable
Logic Controller (PLC), allowing its use in industrial applications
without significant increase on machine cost. All algorithms
were developed having in mind safety issues relative to
the operation of the cutting machine in order to prevent catastrophic
failure. Also, all process related relevant parameters
are monitored on a Personal Computer using OPC (Object
Linking and Embedding – for Process Control)
Sand bypass and updrift beach evolution after jetty construction at an ebb-tidal delta
The evolution of an ebb-tidal delta (Guadiana, South Portugal) and its updrift beach after jetty construction
(in 1972e1974) is analysed based on 24 ortho-rectified aerial photographs (1940e2012) and 13
bathymetric maps (1969e2014). The objectives are to evaluate the re-establishment of the sand
bypassing process and if the disruption of the historical delta may affect the updrift beach evolution.
Post-jetty progradation of the updrift beach resulted from two large accretion events. The second
(largest) event (110 m progradation in 1985e1994) was due to beach attachment of a shoal produced by
the erosion of a broad shallow area relict of the historical delta. The reworking of sand from this relict
area also enables the individualisation of a lateral updrift bar simultaneously with the new ebb shoal
proper formation. Both morphological features were close to (volume) equilibrium in 1995, indicating
that most of the sand was transported towards the downdrift side of the inlet at that time. This study
shows that erosion of the historical delta may enhance significantly the updrift shoreline progradation
and may promote the re-establishment of sand bypassing after jetty construction.The following institutions in Portugal are acknowledged for
providing some of the bathymetric maps used in this study: Ministry
of Public Works, Transport and Communications (MOPTC);
Hydrographic Institute (IH); and, Port and Maritime Transport
Institute (IPTM).info:eu-repo/semantics/publishedVersio
Intercâmbio e quarentena de germoplasma vegetal no perĂodo de 2004 a 2007.
bitstream/CENARGEN/29595/1/cot158.pd
A mobile environmental monitoring station for sustainable cities
The aim of this paper is to present a mobile environmental monitoring station to evaluate the urban environment. The different phases of the mobile unit development are presented from its construction and operation mode for handling and sharing the data obtained. This mobile unit measures the following urban environmental parameters: environmental noise (Leq, L10 and L90), air quality (PM10, PM2.5 and Total Suspended Particles) and meteorological parameters (air temperature, relative humidity, wind speed and wind direction).
This mobile unit is part of a project developed for the Portuguese city of Vila Real, called SMMART (in English "Municipal System for Monitoring Air, Noise and Traffic"). The municipality accepted the challenge of developing a platform whereby the population could be informed about the quality of the urban environment (air and noise) of the city where they live.(undefined
A 2.4-GHz wireless sensor network for smart electronic shirts integration
A typical sensing module is composed of sensors,
interface electronics, a radio-frequency (RF) CMOS
transceiver and an associated antenna. A 2.4-GHz RF
transceiver chip was fabricated in a UMC 0.18 ÎĽm CMOS
process. The receiver has a sensibility of -60 dBm and
consumes 6.3 mW from a 1.8 V supply. The transmitter
delivers an output power of 0 dBm with a power consumption
of 11.2 mW. Innovative topics concerning efficient power
management was taken into account during the design of the
transceiver. A solution of individual sensing modules allows a
plug-and-play solution. The target application is the
integration of a wireless sensor network in smart electronic
shirts, for monitoring the cardio-respiratory function and
posture
Scattering from supramacromolecular structures
We study theoretically the scattering imprint of a number of branched
supramacromolecular architectures, namely, polydisperse stars and dendrimeric,
hyperbranched structures. We show that polydispersity and nature of branching
highly influence the intermediate wavevector region of the scattering structure
factor, thus providing insight into the morphology of different aggregates
formed in polymer solutions.Comment: 20 pages, 8 figures To appear in PR
Enhanced separation of bioactive triterpenic acids with a triacontylsilyl silica gel adsorbent: from impulse and breakthrough experiments to the design of a simulated moving bed unit
A simulated moving bed (SMB) unit was designed to separate oleanolic and ursolic acids, two naturally occurring triterpenoids with structural isomerism, with remarkable nutraceutical and pharmacological properties. A triacontylsilyl silica gel adsorbent (stationary phase of an Acclaim C30 column) was considered and impulse tests with different solvents were performed to select a mobile phase, from which methanol/water 95/5 (%, v/v) emerged as the most suitable. Equilibrium and global mass transport coefficients were then determined through breakthrough experiments using pure compound solutions and the C30 column. Afterwards, these parameters were applied to the simulation of two model binary mixture separations, whose breakthrough curves were also experimentally measured.
Finally, the SMB unit was designed and optimized. It was demonstrated that using the packing of an Acclaim C30 column and methanol/water 95/5 (%, v/v) as mobile phase it is possible to separate both acids with purities of 99.9 wt.%, a productivity of 1.705 kg/(m3adsorbent day), and a configuration of two columns per section (2–2–2–2). The simulated results obtained in this work with the C30 stationary phase represent a significant improvement over literature data.publishe
Markedly divergent tree assemblage responses to tropical forest loss and fragmentation across a strong seasonality gradient
We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shadetolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentationinduced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide
Quality of Life and characterization of patients with atopic dermatitis in Portugal - QUADEP study
OBJECTIVES:
To investigate the quality of life (QoL) and to characterize patients with atopic dermatitis (AD) in Portugal.
METHODS:
This was a cross-sectional study, including patients with AD and other eczemas. Skindex-29, Skindex-teen and Childhood Atopic Dermatitis Impact Scale (CADIS) were the instruments used to assess QoL in adults, teenagers, and children respectively. Complementarily, the SF-12 was used and disease severity was evaluated through Patient-Oriented SCORAD (PO-SCORAD). Odds Ratio (OR) were performed to measure associations with QoL. SPSS statistics 95% confidence intervals and values of p<0.05 were considered statistically significant.
RESULTS:
162 participants were included, aging 0.5-74 years. We found that 37.3% of AD patients consider their disease as disabling and more than half of AD patients feel stigmatized by society. The mean Skindex score for AD was 39.68, and 44% patients presented a severe QoL impact. "Symptoms" was the most affected category in adults. Moderate to severe AD patients were 87% of the sample. Regarding the factors that most influenced worse QoL in AD, with increasing age, the Skindex score is likely to increase (OR: 1.03 [95%CI 1.00-1.06]). "Consider having disability" was also associated, OR: 6.72 (95%CI 2.56-17.63). With increasing affected body area and edema, the QoL worsens (OR: 1.07 [95%CI 1.03-1.11] and OR: 2.04 [95%CI 1.23-3.40], respectively).
CONCLUSIONS:
This is the first study with QoL data about AD patients in Portugal, revealing an expected negative impact. More awareness-raising activities are needed to increase literacy, decrease the stigma, and consequently to address some impacted factors in AD patients' QoL.info:eu-repo/semantics/publishedVersio
NEEM: network-friendly epidemic multicast
Epidemic, or probabilistic, multicast protocols have emerged as a viable mechanism to circumvent the scalabil- ity problems of reliable multicast protocols. However, most existing epidemic approaches use connectionless transport protocols to exchange messages and rely on the intrinsic robustness of the epidemic dissemination to mask network omissions. Unfortunately, such an approach is not network- friendly, since the epidemic protocol makes no effort to re- duce the load imposed on the network when the system is congested. In this paper, we propose a novel epidemic protocol whose main characteristic is to be network-friendly. This property is achieved by relying on connection-oriented transport connections, such as TCP/IP, to support the com- munication among peers. Since during congestion mes- sages accumulate in the border of the network, the pro- tocol uses an innovative buffer management scheme, that combines different selection techniques to discard messages upon overflow. This technique improves the quality of the information delivered to the application during periods of network congestion. The protocol has been implemented and the benefits of the approach are illustrated using a com- bination of experimental and simulation results
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