Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

2014

Satellite-based evapotranspiration of a super-intensive olive orchard: Application of METRIC algorithms

Authors
Pocas, I; Paco, TA; Cunha, M; Andrade, JA; Silvestre, J; Sousa, A; Santos, FL; Pereira, LS; Allen, RG;

Publication
BIOSYSTEMS ENGINEERING

Abstract
METRIC (TM) is a satellite-based surface energy balance model aimed at estimating and mapping crop evapotranspiration (ET). It has been applied to a large range of vegetation types, mostly annual crops. When applied to anisotropic woody canopies, such as olive orchards, extensions are required to algorithms for estimating the leaf area index (LAI), surface temperature, and momentum roughness length (Z(om)). The computation of the radiometric surface temperature needs to consider a three-source condition, thus differentiating the temperature of the canopy (T-c), of the shaded ground surface (T-shadow), and of the sunlit ground surface (T-sunlit). The estimation of the Z(om) for tall and incomplete cover is based upon the LAI and crop height using the Perrier equation. The LAI, Zorn, and temperature derived from METRIC after these adjustments were tested against field collected data with good results. The application of METRIC to a two year set of Landsat images to estimate ET of a super-intensive olive orchard in Southern Portugal produced good ET estimates that compared well with ground-based ET. The analysis of METRIC performance showed a quantitative improvement of ET estimates when applying the three-source condition for temperature estimation, as well as the Z(om) computation with the Perrier equation. Results show that METRIC can be used operationally to estimate and mapping ET of super-intensive olive orchards aiming at improving irrigation water use and management.

2014

Assessing lean deployment in healthcare-a critical review and framework

Authors
Guimarães, CM; De Carvalho, JC;

Publication
Journal of Enterprise Transformation

Abstract
This article presents a critical review of lean assessment in manufacturing and service settings as a base for development of a lean assessment framework for healthcare organizations, aiming to help them throughout a long journey. Having as starting point lean projects’ failures in four public hospitals, the authors discover the lack of monitoring (among other reasons) as the main issue. This article proposes a monitoring instrument for preventing returns to the comfort zone and guiding the lean journey. The healthcare lean assessment (HLA) can be used as an “as is” diagnosis tool, assessing whether each process should be improved, disrupted, or eliminated and also as an ongoing implementation assessment, providing control measures and correction actions. Although the framework proposed requires empirical testing in further research for universal application, it can help healthcare organizations by providing a transformation roadmap and monitoring instrument and also contributes to the growing stream of academic research in this area. © IIE, INCOSE.

2014

AN ASYMPTOTIC UNIVERSAL FOCAL DECOMPOSITION FOR NON-ISOCHRONOUS POTENTIALS

Authors
De Carvalho, CAA; Peixoto, MM; Pinheiro, D; Pinto, AA;

Publication
TRANSACTIONS OF THE AMERICAN MATHEMATICAL SOCIETY

Abstract
Galileo, in the seventeenth century, observed that the small oscillations of a pendulum seem to have constant period. In fact, the Taylor expansion of the period map of the pendulum is constant up to second order in the initial angular velocity around the stable equilibrium. It is well known that, for small oscillations of the pendulum and small intervals of time, the dynamics of the pendulum can be approximated by the dynamics of the harmonic oscillator. We study the dynamics of a family of mechanical systems that includes the pendulum at small neighbourhoods of the equilibrium but after long intervals of time so that the second order term of the period map can no longer be neglected. We analyze such dynamical behaviour through a renormalization scheme acting on the dynamics of this family of mechanical systems. The main theorem states that the asymptotic limit of this renormalization scheme is universal: it is the same for all the elements in the considered class of mechanical systems. As a consequence, we obtain a universal asymptotic focal decomposition for this family of mechanical systems. This paper is intended to be the first in a series of articles aiming at a semiclassical quantization of systems of the pendulum type as a natural application of the focal decomposition associated to the two-point boundary value problem.

2014

Optimization of storage space in port grain cereal storage silos – A case study

Authors
Cardoso, MG; Ferreira, EP; Lopes, MP; Lopes, C;

Publication
Engineering Optimization IV - Proceedings of the 4th International Conference on Engineering Optimization, ENGOPT 2014

Abstract
In this paper, we present a novel mixed integer linear programming (MIP) model to solve the problem of storage space optimization in a port grain cereal silo. This work is based on a real case study for scheduling storage operations in a port cereal silo, where schedulers are faced daily with the problem of finding the best solution for transfers between storage cells, to maximize the number of empty cells, in order to have greater capacity to receive new lots, subject to storage and transportation lines capacity constraints, and receiving dispatching plans. The problem is formulated by a mixed integer linear programming model and implemented in an Excel/VBA platform. The results show that the model optimizes the number of empty cells, in computational time less than 60 seconds, and thereby constitutes a significant added value to the concerned company. © 2015 Taylor & Francis Group, London.

2014

Teaching Optics with the centennial universal lantern

Authors
Joao Carvalhal, MJ; Monteiro, M; Marques, MB;

Publication
12TH EDUCATION AND TRAINING IN OPTICS AND PHOTONICS CONFERENCE

Abstract
A projection apparatus was bought in 1909 by the Physics Cabinet of the Polytechnic Academy (predecessor to the University of Porto's Faculty of Science) in order to present various physics experiments, mostly in the realm of Optics, to a large student audience. A stout and impressive mahogany and brass piece, with a voltaic arc lighting system, it was manufactured by the firm E. Leybold's Nachfolger, based in Chemnitz (Germany), already with a worldwide reputation as a supplier of teaching instruments and equipment to superior schools and universities. It was sold along with an extensive set of accessories, allowing for demonstrations in geometrical optics, spectrum analysis, interferometry, diffraction, polarization and double refraction. Two extra attachments, one for projecting microscopic objects, and the other for the projection of gypsum preparations in polarized light, added to the versatility of this lantern, appropriately dubbed of universal use. Both apparatus and accessories are presently to be found in the collection of the Museum of Science of our University. On studying them, we have come to the conclusion that many classical experiments in Optics may be displayed, without great effort and in an attractive manner. The adaptation to present day usage takes no more than the replacement of the lantern's voltaic arc by a suitable and safer light source. It so happens that a hundred-year old projection apparatus, fitted with a set of purposely designed add-ons, becomes so effective as its modern counterparts.

2014

Evapotranspiration and crop coefficients for a super intensive olive orchard. An application of SIMDualKc and METRIC models using ground and satellite observations

Authors
Paco, TA; Pocas, I; Cunha, M; Silvestre, JC; Santos, FL; Paredes, P; Pereira, LS;

Publication
JOURNAL OF HYDROLOGY

Abstract
The estimation of crop evapotranspiration (ETc) from the reference evapotranspiration (ETo) and a standard crop coefficient (K-c) in olive orchards requires that the latter be adjusted to planting density and height. The use of the dual K-c approach may be the best solution because the basal crop coefficient K-cb represents plant transpiration and the evaporation coefficient reproduces the soil coverage conditions and the frequency of wettings. To support related computations for a super intensive olive orchard, the model SIMDualKc was adopted because it uses the dual K-c approach. Alternatively, to consider the physical characteristics of the vegetation, the satellite-based surface energy balance model METRIC (TM) - Mapping EvapoTranspiration at high Resolution using Internalized Calibration - was used to estimate ETc and to derive crop coefficients. Both approaches were compared in this study. SIMDualKc model was calibrated and validated using sap-flow measurements of the transpiration for 2011 and 2012. In addition, eddy covariance estimation of ETc was also used. In the current study, METRIC (TM), was applied to Landsat images from 2011 to 2012. Adaptations for incomplete cover woody crops were required to parameterize METRIC. It was observed that ETc obtained from both approaches was similar and that crop coefficients derived from both models showed similar patterns throughout the year. Although the two models use distinct approaches, their results are comparable and they are complementary in spatial and temporal scales.

  • 2944
  • 4387