Santiago Correa V. - Profile on Academia.edu (original) (raw)
Papers by Santiago Correa V.
LIRIS is an Instituto de Astrofísica de Canarias project that consists of a near-infrared interme... more LIRIS is an Instituto de Astrofísica de Canarias project that consists of a near-infrared intermediate- resolution spectrograph, conceived as a common user instrument for the William Herschel Telescope at the Observatorio del Roque de los Muchachos (La Palma).
URIS is a near-infrared (0.9-2.4 microns) intermediate resolution spectrograph (R=1000-3000) conc... more URIS is a near-infrared (0.9-2.4 microns) intermediate resolution spectrograph (R=1000-3000) conceived as a common user instrument for the (WHT) at the Observatorio del Roque de los Muchachos (ORM) La Palma. URIS is now being assembled, integrated and verified at the Instituto AstrofIsico de Canarias (IAC).
Constituents of roots of Inga edulis var. parviflora
Fitoterapia, 1995
This article presents a finite element formulation based on a parameterized variational principle... more This article presents a finite element formulation based on a parameterized variational principle for solving plane problems of fluidstructure interaction using the displacements as state variable for both solid and fluid media. The circular spurious modes, typical of displacement formulations are avoided. The penalty parameter is not random because it is selected according to energy criterion. Finally the formulation is not sensible to the definition of the normal direction in the fluidstructure interface.
Resistencia de dientes restaurados con postes prefabricados ante cargas de máxima intercuspidación, masticación y bruxismo
Revista cubana de estomatología
Large Lenses and Prisms
EMIR is a multiobject intermediate resolution near infrared (1.0 - 2.5 microns) spectrograph with... more EMIR is a multiobject intermediate resolution near infrared (1.0 - 2.5 microns) spectrograph with image capabilities to be mounted on the Gran Telescopio Canarias (Observatorio del Roque de los Muchachos, La Palma, Spain). EMIR is under design by a consortium of Spanish, French and British institutions, led by the Instituto de Astrofisica de Canarias. This work has been partially funded by the GTC Project Office. The instrument will deliver images and spectra in a large FOV (6 X 6 arcmin), and because of the telescope image scale (1 arcmin equals 52 mm) and the spectral resolution required, around 4000, one of the major challenges of the instrument is the optics and optomechanics. Different approaches have been studied since the initial proposal, trying to control the risks of the instrument, while fitting the initial scientific requirements. Issues on optical concepts, material availability, temperature as well as optomechanical mounting of the instrument will be presented.© (2002)...
Differences in the microstructure and fatigue properties of dentine between residents of North and South America
Archives of Oral Biology, 2014
Spatial variations in the microstructure of dentine contribute to its mechanical behaviour. The o... more Spatial variations in the microstructure of dentine contribute to its mechanical behaviour. The objective of this investigation was to compare the microstructure and fatigue behaviour of dentine from donors of two different countries. Caries-free third molars were obtained from dental practices in Colombia, South America and the US to assemble two age-matched samples. The microstructure of the coronal dentine was evaluated at three characteristic depths (i.e. deep, middle and superficial dentine) using scanning electron microscopy and image processing techniques. The mechanical behaviour of dentine in these three regions was evaluated by the fatigue crack growth resistance. Cyclic crack growth was achieved in-plane with the dentine tubules and the fatigue crack growth behaviour was characterized in terms of the stress intensity threshold and the Paris Law parameters. There was no difference in the tubule density between the dentine of patients from the two countries. However, there were significant differences (p≤0.05) in the tubule lumen diameters between the two groups in the deep and peripheral regions. In regards to the fatigue resistance, there was a significant increase (p≤0.05) in threshold stress intensity range, and a significant decrease in fatigue crack growth coefficient with increasing distance from the pulp in teeth from the US donors. In contrast, these properties were independent of location for the dentine of teeth from the Colombian donors. The microstructure of dentine and its mechanical behaviour appear to be a function of patient background, which may include environmental factors and/or ethnicity.
Latin American Journal of Solids and Structures, 2012
A three node -displacement based-acoustic element is developed. In order to avoid spurious rotati... more A three node -displacement based-acoustic element is developed. In order to avoid spurious rotational modes, a higher order stiffness is introduced. This higher order stiffness is developed from an incompatible strain field which computes element volume changes under nodal rotational displacements fields. The higher order strain resulting from the incompatible strain field satisfies the Individual Element Test (IET) requirements without affecting convergence. The higher order stiffness is modulated, element by element, with a factor. As a result, the displacement based formulation presented on this paper is capable of placing the spurious rotational modes above the range of the physical compressional modes that can be accurately calculated by the mesh.
Journal of Prosthodontic Research, 2012
Purpose: There is much controversy about the minimum number of implants and maximum cantilever le... more Purpose: There is much controversy about the minimum number of implants and maximum cantilever length in mandible prosthetic restoration. Finite elements analysis of three and four implant-supported prostheses was performed to determine the stresses in the superstructure, implants and cortical bone and, therefore, the failure prediction for each restoration. Methods: An edentulous mandible was modeled from CT scan images. Two finite element models of three and four implant-supported prostheses with cantilever lengths of 10 and 15 mm were created. Occlusal loads in different parts of the superstructure were applied and shear and normal stresses were calculated. Results: Two failure criteria were analyzed: the von Mises criterion for isotropic materials (superstructure and implants) and the Tsai-Wu criterion for transversely isotropic material (cortical bone). Both criteria predict failure in the three implant-supported prosthesis for all cases analyzed. The same applies for the four-implant prosthesis of 15 mm cantilever length. However, four implants and a cantilever length of 10 mm passed the failure criteria and were considered safe. Conclusions: The results from the patient analyzed showed that fixed support prostheses on three implants are not recommended from a structural point of view because they do not adequately support occlusal loads. Excessive stress in the superstructure and the cortical bone can be expected, which would anticipate the failure of the restoration. Fixed support prostheses on four implants with a cantilever length of 10 mm properly resist occlusal loading.
Ground-based Instrumentation for Astronomy, 2004
LIRIS is a near-infrared intermediate resolution spectrograph with added capabilities for multi-s... more LIRIS is a near-infrared intermediate resolution spectrograph with added capabilities for multi-slit, imaging, coronography, and polarimetry, developed by the Instituto de Astrofisica de Canarias (IAC). It will be a common user instrument for the Cassegrain focus of the William Herschel Telescope (WHT) at the Roque de los Muchachos Observatory in La Palma. At its first commissioning, that was held in
Instrument Design and Performance for Optical/Infrared Ground-based Telescopes, 2003
ABSTRACT
Ground-based and Airborne Instrumentation for Astronomy, 2006
EMIR is the NIR multi-object imager and spectrograph for the GTC (Gran Telescopio Canarias). The ... more EMIR is the NIR multi-object imager and spectrograph for the GTC (Gran Telescopio Canarias). The instrument ADR (Advanced Design Review) was held successfully in March 2006. During the AD phase, a number of mechanical concepts were tested on development prototypes to ensure the feasibility of the PDR proposed designs. This presentation contains an overview of the current mechanical status of
Optomechanics 2005, 2005
EMIR is a NIR multiobject spectrograph with imaging capabilities to be used at the GTC. The first... more EMIR is a NIR multiobject spectrograph with imaging capabilities to be used at the GTC. The first collimator lens in EMIR, made of Fused Silica, has an outer diameter of 490 mm, and a weight of 265 N, which make it one of the largest Fused Silica lenses ever mounted to work under cryogenic conditions. The results of the various tests being done at the IAC (with two different lens dummies) in order to validate a mounting design concept for this lens, are presented here. The radial support concept tested consists of three contact areas around the lens, one of which is a PTFE block, preloaded by coil springs and the other two are fixed supports made of Aluminum and PTFE, dimensioned in order to keep lens centered both at room temperature and under operation conditions.
Airborne Telescope Systems II, 2003
ABSTRACT VERA (VLBI Exploration of Radio Astrometry), being promoted by National Astronomical Obs... more ABSTRACT VERA (VLBI Exploration of Radio Astrometry), being promoted by National Astronomical Observatory of Japan in collaboration with several Japanese universities, is a new VLBI array for phase referencing astrometry approved to start its construction in 2000. VERA, the first VLBI array dedicated to phase referencing VLBI, has a dual beam antenna system which enables us to observe a Galactic maser source and a nearby reference source simultaneously to remove the atmospheric fluctuation, and will measure positions of Galactic maser sources relative to reference sources (QSOs and radio galaxies) with 10 microarcsec level accuracy. With that accuracy, VERA will be able to determine parallaxes and proper motions of maser sources in the whole Galaxy. The major science targets of VERA will include 3D structure of the Galaxy and the distribution of dark matter, physics of outflow in star forming regions and stellar envelopes, precise calibration of the period-luminosity relation of Mira-type stars, and structure an evolution of QSOs and radio galaxies.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Instrument Design and Performance for Optical/Infrared Ground-based Telescopes, 2003
URIS is a near-infrared (0.9-2.4 microns) intermediate resolution spectrograph (R=1000-3000) conc... more URIS is a near-infrared (0.9-2.4 microns) intermediate resolution spectrograph (R=1000-3000) conceived as a common user instrument for the (WHT) at the Observatorio del Roque de los Muchachos (ORM) La Palma. URIS is now being assembled, integrated and verified at the Instituto AstrofIsico de Canarias (IAC).
Instrument Design and Performance for Optical/Infrared Ground-based Telescopes, 2003
OSIRIS (Optical System for Imaging and low Resolution Integrated Spectroscopy) is the optical Day... more OSIRIS (Optical System for Imaging and low Resolution Integrated Spectroscopy) is the optical Day One instrument for the 10.4m Spanish telescope GTC to be installed in the Observatorio del Roque de Los Muchachos (La Palma, Spain). This instrument, operational in mid-2004, covers from 360 up to 1000 nm. OSIRIS observing modes include direct imaging with tunable and conventional filters, long slit and multiple object spectroscopy and fast spectrophotometry. The OSIRIS wide field of view, high efficiency and the new observing modes (tunable imaging and fast spectrophotometry) for 8-10m class telescopes will provide GTC with a powerful tool for their scientific exploitation. The present paper provides an updated overview of the instrument development, of some of the scientific projects that will be tackled with OSIRIS and of the general requirements driving the optical and mechanical design.
Large Lenses and Prisms, 2002
Ground-based Instrumentation for Astronomy, 2004
This paper shows the different design concepts and techniques employed in the structural and ther... more This paper shows the different design concepts and techniques employed in the structural and thermal analysis of EMIR (Espectrógrafo Multiobjeto Infrarrojo), nowadays under development at the Instituto de Astrofísica de Canarias.
Ground-based Instrumentation for Astronomy, 2004
EMIR is the NIR multi-object imager and spectrograph for the GTC (Gran Telescopio Canarias). The ... more EMIR is the NIR multi-object imager and spectrograph for the GTC (Gran Telescopio Canarias). The instrument PDR phase was held successfully in March 2003, and we are at present in the middle of the ADR (Advanced Design Phase) during which a number of mechanical concepts will be tested on development prototypes to ensure the feasibility of the PDR proposed design. This presentation contains a technical description of the mechanical design of the instrument, as well as the prototypes development. The mechanical design is essentially built around the optical layout by providing an optical bench for mounting the optomechanics, the mechanisms and the detector, all this inside a custom-designed vacuum vessel and with the corresponding cooling system. One of its main design features is the use of a cryogenic reconfigurable slit mechanism to generate a multi-slit configuration, a long slit or an imaging aperture at the telescope focal plane. This feature will permit to maintain the instrument in operation conditions for a long time and take advantages in both a classically scheduled and a queued service observing schemes
Ground-based Instrumentation for Astronomy, 2004
LIRIS is an Instituto de Astrofísica de Canarias project that consists of a near-infrared interme... more LIRIS is an Instituto de Astrofísica de Canarias project that consists of a near-infrared intermediate- resolution spectrograph, conceived as a common user instrument for the William Herschel Telescope at the Observatorio del Roque de los Muchachos (La Palma).
URIS is a near-infrared (0.9-2.4 microns) intermediate resolution spectrograph (R=1000-3000) conc... more URIS is a near-infrared (0.9-2.4 microns) intermediate resolution spectrograph (R=1000-3000) conceived as a common user instrument for the (WHT) at the Observatorio del Roque de los Muchachos (ORM) La Palma. URIS is now being assembled, integrated and verified at the Instituto AstrofIsico de Canarias (IAC).
Constituents of roots of Inga edulis var. parviflora
Fitoterapia, 1995
This article presents a finite element formulation based on a parameterized variational principle... more This article presents a finite element formulation based on a parameterized variational principle for solving plane problems of fluidstructure interaction using the displacements as state variable for both solid and fluid media. The circular spurious modes, typical of displacement formulations are avoided. The penalty parameter is not random because it is selected according to energy criterion. Finally the formulation is not sensible to the definition of the normal direction in the fluidstructure interface.
Resistencia de dientes restaurados con postes prefabricados ante cargas de máxima intercuspidación, masticación y bruxismo
Revista cubana de estomatología
Large Lenses and Prisms
EMIR is a multiobject intermediate resolution near infrared (1.0 - 2.5 microns) spectrograph with... more EMIR is a multiobject intermediate resolution near infrared (1.0 - 2.5 microns) spectrograph with image capabilities to be mounted on the Gran Telescopio Canarias (Observatorio del Roque de los Muchachos, La Palma, Spain). EMIR is under design by a consortium of Spanish, French and British institutions, led by the Instituto de Astrofisica de Canarias. This work has been partially funded by the GTC Project Office. The instrument will deliver images and spectra in a large FOV (6 X 6 arcmin), and because of the telescope image scale (1 arcmin equals 52 mm) and the spectral resolution required, around 4000, one of the major challenges of the instrument is the optics and optomechanics. Different approaches have been studied since the initial proposal, trying to control the risks of the instrument, while fitting the initial scientific requirements. Issues on optical concepts, material availability, temperature as well as optomechanical mounting of the instrument will be presented.© (2002)...
Differences in the microstructure and fatigue properties of dentine between residents of North and South America
Archives of Oral Biology, 2014
Spatial variations in the microstructure of dentine contribute to its mechanical behaviour. The o... more Spatial variations in the microstructure of dentine contribute to its mechanical behaviour. The objective of this investigation was to compare the microstructure and fatigue behaviour of dentine from donors of two different countries. Caries-free third molars were obtained from dental practices in Colombia, South America and the US to assemble two age-matched samples. The microstructure of the coronal dentine was evaluated at three characteristic depths (i.e. deep, middle and superficial dentine) using scanning electron microscopy and image processing techniques. The mechanical behaviour of dentine in these three regions was evaluated by the fatigue crack growth resistance. Cyclic crack growth was achieved in-plane with the dentine tubules and the fatigue crack growth behaviour was characterized in terms of the stress intensity threshold and the Paris Law parameters. There was no difference in the tubule density between the dentine of patients from the two countries. However, there were significant differences (p≤0.05) in the tubule lumen diameters between the two groups in the deep and peripheral regions. In regards to the fatigue resistance, there was a significant increase (p≤0.05) in threshold stress intensity range, and a significant decrease in fatigue crack growth coefficient with increasing distance from the pulp in teeth from the US donors. In contrast, these properties were independent of location for the dentine of teeth from the Colombian donors. The microstructure of dentine and its mechanical behaviour appear to be a function of patient background, which may include environmental factors and/or ethnicity.
Latin American Journal of Solids and Structures, 2012
A three node -displacement based-acoustic element is developed. In order to avoid spurious rotati... more A three node -displacement based-acoustic element is developed. In order to avoid spurious rotational modes, a higher order stiffness is introduced. This higher order stiffness is developed from an incompatible strain field which computes element volume changes under nodal rotational displacements fields. The higher order strain resulting from the incompatible strain field satisfies the Individual Element Test (IET) requirements without affecting convergence. The higher order stiffness is modulated, element by element, with a factor. As a result, the displacement based formulation presented on this paper is capable of placing the spurious rotational modes above the range of the physical compressional modes that can be accurately calculated by the mesh.
Journal of Prosthodontic Research, 2012
Purpose: There is much controversy about the minimum number of implants and maximum cantilever le... more Purpose: There is much controversy about the minimum number of implants and maximum cantilever length in mandible prosthetic restoration. Finite elements analysis of three and four implant-supported prostheses was performed to determine the stresses in the superstructure, implants and cortical bone and, therefore, the failure prediction for each restoration. Methods: An edentulous mandible was modeled from CT scan images. Two finite element models of three and four implant-supported prostheses with cantilever lengths of 10 and 15 mm were created. Occlusal loads in different parts of the superstructure were applied and shear and normal stresses were calculated. Results: Two failure criteria were analyzed: the von Mises criterion for isotropic materials (superstructure and implants) and the Tsai-Wu criterion for transversely isotropic material (cortical bone). Both criteria predict failure in the three implant-supported prosthesis for all cases analyzed. The same applies for the four-implant prosthesis of 15 mm cantilever length. However, four implants and a cantilever length of 10 mm passed the failure criteria and were considered safe. Conclusions: The results from the patient analyzed showed that fixed support prostheses on three implants are not recommended from a structural point of view because they do not adequately support occlusal loads. Excessive stress in the superstructure and the cortical bone can be expected, which would anticipate the failure of the restoration. Fixed support prostheses on four implants with a cantilever length of 10 mm properly resist occlusal loading.
Ground-based Instrumentation for Astronomy, 2004
LIRIS is a near-infrared intermediate resolution spectrograph with added capabilities for multi-s... more LIRIS is a near-infrared intermediate resolution spectrograph with added capabilities for multi-slit, imaging, coronography, and polarimetry, developed by the Instituto de Astrofisica de Canarias (IAC). It will be a common user instrument for the Cassegrain focus of the William Herschel Telescope (WHT) at the Roque de los Muchachos Observatory in La Palma. At its first commissioning, that was held in
Instrument Design and Performance for Optical/Infrared Ground-based Telescopes, 2003
ABSTRACT
Ground-based and Airborne Instrumentation for Astronomy, 2006
EMIR is the NIR multi-object imager and spectrograph for the GTC (Gran Telescopio Canarias). The ... more EMIR is the NIR multi-object imager and spectrograph for the GTC (Gran Telescopio Canarias). The instrument ADR (Advanced Design Review) was held successfully in March 2006. During the AD phase, a number of mechanical concepts were tested on development prototypes to ensure the feasibility of the PDR proposed designs. This presentation contains an overview of the current mechanical status of
Optomechanics 2005, 2005
EMIR is a NIR multiobject spectrograph with imaging capabilities to be used at the GTC. The first... more EMIR is a NIR multiobject spectrograph with imaging capabilities to be used at the GTC. The first collimator lens in EMIR, made of Fused Silica, has an outer diameter of 490 mm, and a weight of 265 N, which make it one of the largest Fused Silica lenses ever mounted to work under cryogenic conditions. The results of the various tests being done at the IAC (with two different lens dummies) in order to validate a mounting design concept for this lens, are presented here. The radial support concept tested consists of three contact areas around the lens, one of which is a PTFE block, preloaded by coil springs and the other two are fixed supports made of Aluminum and PTFE, dimensioned in order to keep lens centered both at room temperature and under operation conditions.
Airborne Telescope Systems II, 2003
ABSTRACT VERA (VLBI Exploration of Radio Astrometry), being promoted by National Astronomical Obs... more ABSTRACT VERA (VLBI Exploration of Radio Astrometry), being promoted by National Astronomical Observatory of Japan in collaboration with several Japanese universities, is a new VLBI array for phase referencing astrometry approved to start its construction in 2000. VERA, the first VLBI array dedicated to phase referencing VLBI, has a dual beam antenna system which enables us to observe a Galactic maser source and a nearby reference source simultaneously to remove the atmospheric fluctuation, and will measure positions of Galactic maser sources relative to reference sources (QSOs and radio galaxies) with 10 microarcsec level accuracy. With that accuracy, VERA will be able to determine parallaxes and proper motions of maser sources in the whole Galaxy. The major science targets of VERA will include 3D structure of the Galaxy and the distribution of dark matter, physics of outflow in star forming regions and stellar envelopes, precise calibration of the period-luminosity relation of Mira-type stars, and structure an evolution of QSOs and radio galaxies.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Instrument Design and Performance for Optical/Infrared Ground-based Telescopes, 2003
URIS is a near-infrared (0.9-2.4 microns) intermediate resolution spectrograph (R=1000-3000) conc... more URIS is a near-infrared (0.9-2.4 microns) intermediate resolution spectrograph (R=1000-3000) conceived as a common user instrument for the (WHT) at the Observatorio del Roque de los Muchachos (ORM) La Palma. URIS is now being assembled, integrated and verified at the Instituto AstrofIsico de Canarias (IAC).
Instrument Design and Performance for Optical/Infrared Ground-based Telescopes, 2003
OSIRIS (Optical System for Imaging and low Resolution Integrated Spectroscopy) is the optical Day... more OSIRIS (Optical System for Imaging and low Resolution Integrated Spectroscopy) is the optical Day One instrument for the 10.4m Spanish telescope GTC to be installed in the Observatorio del Roque de Los Muchachos (La Palma, Spain). This instrument, operational in mid-2004, covers from 360 up to 1000 nm. OSIRIS observing modes include direct imaging with tunable and conventional filters, long slit and multiple object spectroscopy and fast spectrophotometry. The OSIRIS wide field of view, high efficiency and the new observing modes (tunable imaging and fast spectrophotometry) for 8-10m class telescopes will provide GTC with a powerful tool for their scientific exploitation. The present paper provides an updated overview of the instrument development, of some of the scientific projects that will be tackled with OSIRIS and of the general requirements driving the optical and mechanical design.
Large Lenses and Prisms, 2002
Ground-based Instrumentation for Astronomy, 2004
This paper shows the different design concepts and techniques employed in the structural and ther... more This paper shows the different design concepts and techniques employed in the structural and thermal analysis of EMIR (Espectrógrafo Multiobjeto Infrarrojo), nowadays under development at the Instituto de Astrofísica de Canarias.
Ground-based Instrumentation for Astronomy, 2004
EMIR is the NIR multi-object imager and spectrograph for the GTC (Gran Telescopio Canarias). The ... more EMIR is the NIR multi-object imager and spectrograph for the GTC (Gran Telescopio Canarias). The instrument PDR phase was held successfully in March 2003, and we are at present in the middle of the ADR (Advanced Design Phase) during which a number of mechanical concepts will be tested on development prototypes to ensure the feasibility of the PDR proposed design. This presentation contains a technical description of the mechanical design of the instrument, as well as the prototypes development. The mechanical design is essentially built around the optical layout by providing an optical bench for mounting the optomechanics, the mechanisms and the detector, all this inside a custom-designed vacuum vessel and with the corresponding cooling system. One of its main design features is the use of a cryogenic reconfigurable slit mechanism to generate a multi-slit configuration, a long slit or an imaging aperture at the telescope focal plane. This feature will permit to maintain the instrument in operation conditions for a long time and take advantages in both a classically scheduled and a queued service observing schemes
Ground-based Instrumentation for Astronomy, 2004