216 research outputs found
Shape acquisition of rotating objects based on Laser Line Scanning
The present work proposes a methodology for 3D shape acquisition of objects through rotation-based Laser Line Scanning. This
enables the acquisition of an object's 3D shape from multiple views,
which leads to a more complete and accurate model
Relationships between leaf water potential and photosynthetic activity of field grapevines grown under different soil water regimes
Relationships between ecophysiological parameters from a grapevine irrigation experiment
(rain-fed vs. deficit irrigation) conducted during 1998 at Alentejo, south of Portugal, with the
red variety Aragonez (syn. Tempranillo) are presented and discussed. The irrigation affected
positively grapevine physiology without changing berry composition. Predawn leaf water
potential shows a significant dependence on available soil water, measured by a neutron
probe, the correlation coefficients being higher in nonirrigated plants than in irrigated ones.
Leaf water potential (Ψ) values measured in exposed leaves in the morning and afternoon
were also significantly correlated with available soil water. Net CO2 assimilation rate (A) and
stomatal conductance (gs) of sun leaves measured throughout the growing season at three
different periods of the day were significantly correlated with predawn leaf water potential,
nonirrigated vines presenting the highest correlation coefficients. Significant correlations
were also found between Ψ and A or gs measured in the early morning. Our results show that,
in water stress conditions, predawn leaf water potential can be used as an indicator of soil
water availability and physiological activity of sun exposed leavesinfo:eu-repo/semantics/publishedVersio
ISO 9001 European Scoreboard: an instrument to measure macroquality
Purpose: ISO 9001 certification is nowadays considered to be one of the most effective
tools that can be adopted for guiding the management of Quality Systems. The stunning
growth observed by these standards all over the world confirms a strong polarisation of
enterprises’ interest in this practice. Owing to the wide incidence of this phenomenon, a
deep investigation of ISO 9001 diffusion over time is mandatory and of importance. In
line with our previous publications, this paper derives from a research project that we
are conducting in Portugal in order to develop the ‘ISO 9001 European Scoreboard’,
aimed at studying and ranking European Union (EU) countries based on the
diffusion of quality management systems. Methodology/approach: In order to
achieve such a goal, the authors have performed a set of statistical analyses over
public data sets. Findings: Based on the model developed and the analyses
performed, we were able to identify clusters of countries with different ISO 9001
evolution stages, derived from the ISO 9001 per 1000 inhabitants’ scores and
countries’ growth indexes. Originality: With this scoreboard, we are able to
categorise and rank countries based on the quality management systems evolution
(growth rates) over the past few years. Ultimately, such an ‘ISO 9001 European
Scoreboard’ will be an instrument to provide a comparative assessment of quality
management practices over the EU states, leading to the dynamic evaluation of their
‘macroquality’ levels achieved, according to such a standard. We believe that such
results provide an additional important contribution to the study of management
systems diffusion/evolution, aimed at providing more fact-based insights and
understandings
Crack Closure Effects on Fatigue Crack Propagation Rates: Application of a Proposed Theoretical Model
Structural design taking into account fatigue damage requires a thorough knowledge of the behaviour of materials. In addition to the monotonic behaviour of the materials, it is also important to assess their cyclic response and fatigue crack propagation behaviour under constant and variable amplitude loading. Materials whenever subjected to fatigue cracking may exhibit mean stress effects as well as crack closure effects. In this paper, a theoretical model based on the same initial assumptions of the analytical models proposed by Hudak and Davidson and Ellyin is proposed to estimate the influence of the crack closure effects. This proposal based further on Walker’s propagation law was applied to the P355NL1 steel using an inverse analysis (back-extrapolation) of experimental fatigue crack propagation results. Based on this proposed model it is possible to estimate the crack opening stress intensity factor, Kop, the relationship between U=ΔKeff/ΔK quantity and the stress intensity factor, the crack length, and the stress ratio. This allows the evaluation of the influence of the crack closure effects for different stress ratio levels, in the fatigue crack propagation rates. Finally, a good agreement is found between the proposed theoretical model and the analytical models presented in the literature
Foreign direct investment and institutional reform : evidence and an application to Portugal
We examine the role of geographic, economic, and institutional factors in attracting Foreign Direct Investment (FDI) in Europe, using a cross-section of inward bilateral investments. We estimate and assess the expected benefits, the required reform efforts, and the efficiency of reform options corresponding to a con- vergence of Portuguese institutions to EU standards. We conclude that improving home institutions is likely to have a quantitatively very significant role in attracting FDI. Geographical and market size factors also play a role. Reforms promoting the independence of financial institutions and a leaner bureaucracy, lowering political risk and corruption, and improving the investment code may significantly affect the amount of bilateral inward FDI that is targeted to Portugal.info:eu-repo/semantics/publishedVersio
Influence on Pitting Corrosion Resistance of AISI 301LN and 316L Stainless Steels Subjected to Cold-Induced Deformation
Analysis of ground reaction force and electromyographic activity of the gastrocnemius muscle during double support
O documento em anexo encontra-se na versão post-print (versão corrigida pelo editor).Purpose: Mechanisms associated with energy expenditure during gait have been extensively researched and studied. According to the double-inverted pendulum model energy expenditure is higher during double support, as lower limbs need to work to redirect the centre of mass velocity. This study looks into how the ground reaction force (GRF) of one limb affects the muscle activity required by the medial gastrocnemius (MG) of the contralateral limb during step-to-step transition. Methods: Thirty-five subjects were monitored as to the MG electromyographic activity (EMGa) of one limb and the GRF of the contralateral limb during double support. Results: After determination of the Pearson correlation coefficient (r), a moderate correlation was observed between the MG EMGa of the dominant leg and the vertical (Fz) and anteroposterior (Fy) components of GRF of the non-dominant leg (r=0.797, p<0.0001; r=-0.807, p<0.0001) and a weak and moderate correlation was observed between the MG EMGa of the non-dominant leg and the Fz and Fy of the dominant leg, respectively (r=0.442, p=0.018; r=-0.684 p<0.0001). Conclusions: The results obtained suggest that during double support, GRF is
associated with the EMGa of the contralateral MG and that there is an increased dependence between the GRF of the non-dominant leg and the EMGa of the dominant MG
Tropical forest lianas have greater non-structural carbohydrate concentrations in the stem xylem than trees
Geometric analysis of female pelvic floor muscles by using manual segmentation
Magnetic Resonance Imaging (MRI) has been used in the diagnostic evaluation of the pelvic floor dysfunctions. MRI can contribute to generate 3D solids of pelvic floor muscles through manual segmentation. The aim of this study is to calculate the area and its moment of inertia of 8 female pelvic floor muscles by using manual segmentation technique. Based on CAD software manual segmentation was used. To build 3D reconstruction models, through of twenty consecutive images. The models were made through splines in each sketch, documenting changes in the pubovisceral muscle (a part from the pelvic floor muscles) from the pubis to coccyx. Two sketches were chosen and biomechanics properties like area and stiffness (moment of inertia) were acquired for each sketch used to generate the pubovisceral muscles. The moment of inertia of the pubovisceral muscle decreases following the order: anterior sketch and posterior sketch. Higher values for the moment of inertia can be encountered in anterior sketcher. This conclusion can lead to more stability in the anterior compartment of pelvic floor visceral
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