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An easy,accurate and efficient procedure to create forest fire risk maps using the SEXTANTE plugin Modeler

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Journal of Forestry Research 2016年第6期27卷 1361-1372页

作者： Lia Duarte Ana Claudia Teododo Earth sciences Institute(ICT) University of PortoRua Campo Alegre4169-007 PortoPortugal Department of Geosciences Environment and Land PlanningFaculty of SciencesUniversity of PortoRua Campo Alegre4169-007 PortoPortugal

To prevent, detect, and protect against forest fires, forest personnel need to define rules for determining forest fire risk. In Portugal, all municipalities must annually produce forest fire risk （FFR） maps. To produce more reliable FFR maps more easily, we developed an open source model using the Modeler plugin of SEXTANTE in the program QGIS version 2.0 Dufour. The model provides all the maps involved in the FFR model （susceptibility map, hazard map, vulnerability map, economic value map, and potential loss map） and was produced according to Portuguese Forest Authority＇s （AFN, Autoridade Florestal Nacional） rules for determining the FFR. This model was tested for the Portuguese municipality Santa Maria da Feira, where 40 % of the total municipality area falls in the category ＂very high＂ or ＂high＂ fire risk. The ＂very high＂ fire risk area is mainly classified as broad-leaved forest and has the steepest slopes （〉15 %）. The distance of burned areas to roads was also analyzed; the proportion of burned areas increased with increasing distance to the main roads. In addition, 92.6 % of the ＂high＂ and ＂very high＂ risk zones were located in areas with lower elevation. These results confirmed that forest fire is strongly influenced not only by environmental factors but also by anthropogenic factors. The procedure implemented here was compared with our open source application already available in QGIS and also to the same procedure implemented in GIS pro- prietary software. Although the results were obviously the same, the model developed here presents several advan- tages over the other two approaches. Besides being faster, it is easy to change the model parameters according to user needs （i.e., to the rules of different countries）, and can be modified and adapted to other variables and other areas to create risk maps for different natural phenomena （e.g., floods, earthquakes, landslides）. The model is easy to use and to create risk and hazard maps rapidly in a free, open

关键词： Forest fire risk (FFR) maps SEXTANTE Modeler. QGIS Open source

Occurrence,leaching,and mobility of major and trace elements in a coal mining waste dump:The case of douro Coalfield,Portugal

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Energy Geoscience 2021年第2期2卷 121-128页

作者： J.Ribeiro D.Flores Department of Earth sciences University of CoimbraRua Silvio Lima3030-790CoimbraPortugal Institute of Earth sciences-porto Pole Rua Do Campo Alegre 6874169-007PortoPortugal Environment and Spatial Planning Department of GeosciencesUniversity of PortoRua Do Campo Alegre 6874169-007PortoPortugal

The coal mining residues from past mining activities in the douro Coalfield are emplaced in many dumps near the mining areas,causing substantial environmental *** study aims to contribute to the investigation of environmental impacts caused by the disposal of the residue in the douro Coalfield through the determination of the geochemical composition of waste materials collected at 3 e 15 m depth,and of the water-leachable fraction produced by percolation in these materials inside the *** elements with higher concentration in the leachates are Ca,Cd,Co,Mg,Mn,Na,Ni,S,and Zn,indicating that they are the most easily leached and accessible elements for percolation and mobilization into the *** presence of these elements in the leachates is principally attributed to their occurrence as water-soluble ions in clays and sulphides affected by natural weathering conditions,which promotes their breakdown and occurrence as exchangeable *** leachates are classified as acid *** weathering and leaching in the Sao Pedro da Cova waste dump are the principal~paths for chemical elements to be percolated and mobilized to environment,posing risk to the soils,waters and ecosystems in the surrounding areas.

关键词： Coal mining Waste dump Water-soluble compound Hazardous element

Advanced Fiber-Optic Acoustic Sensors

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Photonic Sensors 2014年第3期4卷 198-208页

作者： Joao G. V. TEIXEIRA Ivo T. LEITE Susana SILVA Orlando FRAZAO EQS Group Rua Joaquim Dias Rocha 354 4470-221 Maia Portugal lNESC TEC (coordinated by INESC porto) Rua Campo Alegre 687 4169-007 Porto Portugal Department of Physics and Astronomy Faculty of Sciences- University of Porto Rua Campo Alegre 687 4169-007 Porto Portugal

Acoustic sensing is nowadays a very demanding field which plays an important role in modern society, with applications spanning from structural health monitoring to medical imaging. Fiber-optics can bring many advantages to this field, and fiber-optic acoustic sensors show already performance levels capable of competing with the standard sensors based on piezoelectric transducers. This review presents the recent advances in the field of fiber-optic dynamic strain sensing, particularly for acoustic detection. Three dominant technologies are identified - fiber Bragg gratings, interferometric Mach-Zehnder, and Fabry-Perot configurations - and their recent developments are summarized.

关键词： Acoustic sensors fiber optics optical fiber sensors

Nanostrain Measurement Using Chirped Bragg Grating Fabry-Perot Interferometer

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Photonic Sensors 2012年第1期2卷 77-80页

作者： Ricardo M. SILVA Marta S. FERREIRA Jose L. SANTOS Orlando FRAZAO INESC porto Rua do Campo Alegre 687 4169-007 Porto Portugal and Faculty of Sciences of University of Porto Rua do Campo Alegre 687 4169-007 Porto Portugal

A simple nanostrain direct current （DC） measurement system based on a chirped Bragg grating Fabry-Perot （FP） structure is presented. The FP cavity, formed between the chirped fiber Bragg grating （CFBG） and the fiber end face, presents an aperiodic behavior due to the CFBG. A laser located in the fringe pattern slope is used to interrogate the sensing head. The optical power parameter is analyzed when strain is applied, for long and short period fringe pattern wavelengths, and sensitivities of-2.87 μW/με and-5.48μW/με are respectively obtained. This configuration presents a resolution of 70 ε.

关键词： Optical fiber sensor Fabry-Perot interferometer chirped fiber Bragg grating

Ammonia Sensing System Based on Wavelength Modulation Spectroscopy

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Photonic Sensors 2015年第2期5卷 109-115页

作者： Duarte VIVEIROS Joao FERREIRA Susana O. SILVA Joana RIBEIRO Deolinda FLORES Jose L. SANTOS Orlando FRAZAO Jose M. BAPTISTA INESC porto Rua do Campo Alegre 687 4169-007 Porto Portugal Geology Center of the university of porto and Department of Geosciences Environment and Spatial Plannings Facultyof Science at University of Porto Rua do Campo Alegre 687 4169-007 Porto Portugal Department of Physics and Astronomy Faculty of Science at University of Porto Rua do Campo Alegre 687 4169-007 Porto Portugal Competence Center of Exact sciences and Engineering University of Madeira Campus da Penteada 9000-390 Funchal Portugal

A sensing system in the near infrared region has been developed for ammonia sensing based on the wavelength modulation spectroscopy （WMS） principle. The WMS is a rather sensitive technique for detecting atomic/molecular species, presenting the advantage that it can be used in the near-infrared region by using the optical telecommunications technology. In this technique, the laser wavelength and intensity were modulated by applying a sine wave signal through the injection current, which allowed the shift of the detection bandwidth to higher frequencies where laser intensity noise was typically lower. Two multi-pass cells based on free space light propagation with 160 cm and 16 cm of optical path length were used, allowing the redundancy operation and technology validation. This system used a diode laser with an emission wavelength at 1512.21nm, where NH3 has a strong absorption line. The control of the NH3 gas sensing system, as well as acquisition, processing and data presentation was performed.

关键词： Ammonia sensing fiber optic system near infrared region wavelength modulation spectroscopy,environment

Fabrication of Tailored Bragg Gratings by the Phase Mask Dithering/Moving Technique

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Photonic Sensors 2013年第1期3卷 81-96页

作者： Miguel MELO Paulo V. S. MARQUES Department of Physics and Astronomy Faculty of Sciences University of Porto Rua do Campo Alegre 687 4169-007Porto Portugal INESC TEC Rua do Campo Alegre 687 4169-007 Porto Portugal

The most relevant aspects related to the phase mask dithering/moving method for the fabrication of complex Bragg grating designs are reviewed. Details for experimental implementation of this technique is presented, including theoretical analysis of the calibration functions for the correct dither/displacement. Results from tailored Bragg grating structures fabricated by this method are shown. Apodized Bragg gratings with modeled spatial profiles were implemented, resulting in side mode suppression levels of more than 20 dB in gratings showing transmission filtering level higher than 30 dB. Chirped gratings with the spectral bandwidth up to 4 nm, π-shift and sampled Bragg gratings with equalized peaks equally spaced by 0.8 nm （100 GHz） were also fabricated.

关键词： Bragg gratings optical fiber filters optical fiber communications optical fiber sensors

Suspended-core Fibers for Sensing Applications

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Photonic Sensors 2012年第2期2卷 118-126页

作者： Orlando FRAZAO Ricardo M. SILVA Marta S. FERREIRA Jose L. SANTOS Antonio B. LOBO RIBEIRO INESC porto Rua do Campo Alegre 687 4169-007 Porto Portugal faculty of sciences of university of porto rua do campo alegre 687 4169-007 Porto Portugal faculty of Health sciences University Fernando Pessoa Rua Carlos da Maia 296 4200-150 Porto Portugal

A brief review on suspended-core fibers for sensing applications is presented. A historical overview over the previous ten years about this special designed microstructure optical fiber is described. This fiber presents attractive optical properties for chemical/biological or gas measurement, but it can be further explored for alternative sensing solutions, namely, in-fiber interferometers based on the suspended-core or suspended-multi-core fiber, for physical parameter monitoring.

关键词： Optical fiber sensor suspended core fiber interferometry

Fiber Fabry-Perot Interferometer for Curvature Sensing

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Photonic Sensors 2016年第4期6卷 339-344页

作者： Catarina S. MONTEIRO1 Marta S. FERREIRA Susana O. SILVA Jens KOBELKE Kay SCHUSTER JOrg BIERLICH Orlando FRAZAO Department of Physics and Astronomy Sciences Faculty Porto University Rua do Campo Alegre 687 4169-007 Porto Portugal INESC-TEC Rua do Campo Alegre 687 4169-007 Porto Portugal IPHT Jena - Leibniz Institute of Photonic Technology Albert-Einstein-Str. 9 07745 Jena Germany

A curvature sensor based on an Fabry-Perot （FP） interferometer was proposed. A capillary silica tube was fusion spliced between two single mode fibers, producing an FP cavity. Two FP sensors with different cavity lengths were developed and subjected to curvature and temperature. The FP sensor with longer cavity showed three distinct operating regions for the curvature measurement. Namely, a linear response was shown for an intermediate curvature radius range, presenting a maximum sensitivity of 68.52 pm/m-1. When subjected to temperature, the sensing head produced a similar response for different curvature radii, with a sensitivity varying from 0.84 pm/℃ to 0.89 pm/℃, which resulted in a small cross-sensitivity to temperature when the FP sensor was subjected to curvature. The FP cavity with shorter length presented low sensitivity to curvature.

关键词： Curvature measurement Fabry-Perot interferometer optical fiber sensor

Center of Gravity Estimation Using a Reaction Board Instrumented With Fiber Bragg Gratings

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Photonic Sensors 2018年第1期8卷 1-6页

作者： Rui OLIVEIRA Paulo RORIZ Manuel B. MARQUES Orlando FRAZAO INESC TEC Rua do Campo Alegre 687 4150-179 Porto Portugal CIDESD-ISMAI-Institute university of Maia (ISMAl) Av. Carlos Oliveira Campos Castelo da Maia 4475-690 MaiaPortugal Department of Physics and Astronomy Faculty of Sciences University of Porto Rua do Campo Alegre 687 4169-007Porto Portugal

The purpose of the present work is to construct a reaction board based on fiber Bragg gratings （FBGs） that could be used for estimation of the 2D coordinates of the projection of center of gravity （CG） of an object. The apparatus is consisted of a rigid equilateral triangular board mounted on three supports at the vertices, two of which have cantilevers instrumented with FBGs. When an object of known weight is placed on the board, the bending strain of the cantilevers is measured by a proportional wavelength shift of the FBGs. Applying the equilibrium conditions of a rigid body and proper calibration procedures, the wavelength shift is used to estimate the vertical reaction forces and moments of force at the supports and the coordinates of the object＇s CG projection on the board. This method can be used on a regular basis to estimate the CG of the human body or objects with complex geometry and density distribution. An example is provided for the estimation of the CG projection coordinates of two orthopaedic femur bone models, one intact, and the other with a hip stem implant encased. The clinical implications of changing the normal CG location by means of a prosthesis have been discussed.

关键词： Optical fiber sensors fiber Bragg gratings cantilever center of gravity hip prosthesis