h i g h l i g h t s Carbonation behavior of fly ash-slag-cement materials stated by electrochemic... more h i g h l i g h t s Carbonation behavior of fly ash-slag-cement materials stated by electrochemical impedance method. Relationship between carbonation depth and electrochemical parameter is described with an empirical formula. Influence of fly ash and/or slag on the carbonation depth is tracked from analyzing isograms maps.
Se evaluó la resistencia a la corrosión de re- cubrimientos obtenidos por pulverización de un bla... more Se evaluó la resistencia a la corrosión de re- cubrimientos obtenidos por pulverización de un blanco de cromo sobre sustratos de acero AISI H13, mediante el análisis de espectroscopia de impedancia electroquí- mica (EIS) y curvas de polarización Tafel en una solución de NaCl al 3% en peso. Se encontró que estos recubri- mientos presentan una velocidad de corrosión menor a la del sustrato, y que los datos de EIS se ajustan a un circuito eléctrico equivalente que contiene dos elementos de fase constante circuito típico para la interpretación del comportamiento de un electrodo metálico sobre el que ha sido depositado un recubrimiento aislante y poroso.
Revista De La Academia Colombiana De Ciencias Exactas Fisicas Y Naturales, Mar 1, 2012
ResuMen Piratoba Morales, u.; A. Mariño Camargo; J.J. Olaya Flórez: Magnetrón Desbalanceado: Conf... more ResuMen Piratoba Morales, u.; A. Mariño Camargo; J.J. Olaya Flórez: Magnetrón Desbalanceado: Configuración del campo magnético y su correlación con el campo de 2 espiras concéntricas. Rev. Acad. Colomb. Cienc. 36 (138): 37-44, 2012. ISSN 0370-3908.
It shows a process for overlap signals separation by fitting to Gaussians, with aid of Excel pro-... more It shows a process for overlap signals separation by fitting to Gaussians, with aid of Excel pro- gram. This process was applied to quantitative determination of the high current density electro plating Zn-Ni alloys, obtained by Differential Pulse Polarography DPP.
2011 VII Southern Conference on Programmable Logic (SPL), 2011
Abstract Optical Transport Networks (OTN) have emerged as a key enabler to increase the capacity ... more Abstract Optical Transport Networks (OTN) have emerged as a key enabler to increase the capacity of current telecommunication infrastructure. ITU-T Recommendation G. 709 describes these networks by defining a flexible frame structure capable of carrying ...
... after MeV Ion-Induced Shape Deformation * Ulises Morales1, Rosalba Castañeda-Guzmán2, Santiag... more ... after MeV Ion-Induced Shape Deformation * Ulises Morales1, Rosalba Castañeda-Guzmán2, Santiago Jesús Pérez-Ruiz2, Juan-Carlos Cheang-Wong1 ... The studied sam-ples are mounted on a 240 kHz PZT or a 5 MHz ultra-sonic transducer (GE Inspection Technologies). ...
Cobalt oxide and cobalt oxide–silver selective surfaces were prepared in a galvanostatic mode by ... more Cobalt oxide and cobalt oxide–silver selective surfaces were prepared in a galvanostatic mode by means an electrodeposition bath, using different deposition times, on stainless steel substrates. Later, the roughness factor of the selective surfaces, were determined in order to establish one relation with the electrodeposition time and the solar absorptance of the black cobalt and black cobalt–silver coatings.
The surface oxidation of ruthenium catalysts with different roughness factor values has been anal... more The surface oxidation of ruthenium catalysts with different roughness factor values has been analyzed. It is shown that electro formation of oxidized species on the exposed surface of ruthenium is strongly affected by the rougher characteristics of the surface. This effect has been explained through the addition and removal of protons to and from the oxidized species.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2008
Colloidal silica particles are being intensively studied due to their potential applications in c... more Colloidal silica particles are being intensively studied due to their potential applications in catalysis, intelligent materials, optoelectronic devices and coating technology. For this work, spherical sub-micrometer-sized silica particles were prepared by the Stö ber process and deposited onto silicon wafers. The samples were then irradiated at room temperature with Si ions at 8 MeV and fluences up to 5 Â 10 15 Si/cm 2 , under different angles h, ranging from 15°to 75°with respect to the sample normal. The size, size distribution and shape of the silica particles were determined using scanning electron microscopy. After the Si irradiation the as-prepared spherical silica particles turned into ellipsoidal particles, as a result of the increase of the particle dimension perpendicular to the ion beam and a decrease in the direction parallel to the ion beam. This effect increases with the ion fluence, and the dependence of the deformation rate on the irradiation angle is discussed.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2006
Spherical sub-micrometer-sized silica particles were prepared by the Stö ber process, from a reac... more Spherical sub-micrometer-sized silica particles were prepared by the Stö ber process, from a reaction mixture containing tetraethoxysilane, ammonia and ethanol, and deposited into silicon wafers. The samples were then irradiated at room temperature with 4 MeV Si, Ti, Pt or Au ions at a fluence of 4 · 10 15 ions/cm 2 , under an angle of 49°with respect to the sample surface. The size, size distribution and shape of the silica particles were determined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). After the irradiation the spherical silica particles can be turned into ellipsoidal particles, as a result of the increase of the particle dimension perpendicular to the ion beam and a decrease in the direction parallel to the ion beam. This effect increases with the ion fluence and depends on the electronic stopping power of the impinging ion. For the series of 4 MeV ions we used in this work a relative transverse diameter change of 17% per 1 keV/nm was obtained and it seems that no threshold for the electronic energy loss exists.
Spherical submicrometer-sized silica particles were prepared by the Stöber process, from a reacti... more Spherical submicrometer-sized silica particles were prepared by the Stöber process, from a reaction mixture containing tetraethoxysilane, ammonia and ethanol, and deposited onto silicon wafers. While the properties of these SiO2 particles depend on their size, size distribution and shape, monodisperse spherical particles were obtained with a narrow size distribution. The samples were then irradiated at room temperature with Si ions
Page 1. Energy-dependent Deformation of Colloidal Silica Nanoparticles under Room Temperature Irr... more Page 1. Energy-dependent Deformation of Colloidal Silica Nanoparticles under Room Temperature Irradiation with MeV Si Ions Juan-Carlos Cheang-Wong a , Ulises Morales, Eder Reséndiz, and Alejandra López-Suárez Instituto ...
Pt nanoparticles were obtained via the thermal decomposition of (NH 4 ) 2 [PtCl 4 ] (diammonium t... more Pt nanoparticles were obtained via the thermal decomposition of (NH 4 ) 2 [PtCl 4 ] (diammonium tetrachloroplatinate) by heating from room temperature to 760°C. The thermal decomposition process was analyzed using thermogravimetric analysis (TGA) and differential thermal analysis (DTA), X-ray thermodiffraction and infrared spectroscopy. The size and structure of the platinum particles were analyzed using transmission electron microscopy (TEM). The electrochemical activity of Pt particles was assessed by cyclic voltammetry in 0.5 M H 2 SO 4 . The TGA and DTA results suggested that the thermal decomposition of the precursor proceeded in two stages: loss of NH 4 Cl at *300°C, followed by loss of NH 4 Cl and Cl 2 at *372°C. Metallic Pt particles were then produced at temperatures of 372°C and above. At 760°C, the mean ± SD size of the Pt particles was (4.1 ± 1.6) nm, as determined from TEM measurements. In cyclic voltammetry (CV) measurements, an electrode comprised of glassy carbon and Pt particles in 0.5 M H 2 SO 4 exhibited behavior similar to that observed using a polycrystalline Pt electrode.
Corrosion resistance of coatings obtained by sputtering a chromium target were evaluated. The fil... more Corrosion resistance of coatings obtained by sputtering a chromium target were evaluated. The films were deposited on substrates of disk-shaped AISI H13 steel. By means of potentiodynamic polarization curves were able to determine the current density vs. potential for the coated and uncoated substrate and the difference in the corrosion potential Ecorr. All sam- ples with coating showed an increase in Ecorr respect to substrate. The electrochemical tests were conducted in an electrolytic solution of 3% NaCl
h i g h l i g h t s Carbonation behavior of fly ash-slag-cement materials stated by electrochemic... more h i g h l i g h t s Carbonation behavior of fly ash-slag-cement materials stated by electrochemical impedance method. Relationship between carbonation depth and electrochemical parameter is described with an empirical formula. Influence of fly ash and/or slag on the carbonation depth is tracked from analyzing isograms maps.
Se evaluó la resistencia a la corrosión de re- cubrimientos obtenidos por pulverización de un bla... more Se evaluó la resistencia a la corrosión de re- cubrimientos obtenidos por pulverización de un blanco de cromo sobre sustratos de acero AISI H13, mediante el análisis de espectroscopia de impedancia electroquí- mica (EIS) y curvas de polarización Tafel en una solución de NaCl al 3% en peso. Se encontró que estos recubri- mientos presentan una velocidad de corrosión menor a la del sustrato, y que los datos de EIS se ajustan a un circuito eléctrico equivalente que contiene dos elementos de fase constante circuito típico para la interpretación del comportamiento de un electrodo metálico sobre el que ha sido depositado un recubrimiento aislante y poroso.
Revista De La Academia Colombiana De Ciencias Exactas Fisicas Y Naturales, Mar 1, 2012
ResuMen Piratoba Morales, u.; A. Mariño Camargo; J.J. Olaya Flórez: Magnetrón Desbalanceado: Conf... more ResuMen Piratoba Morales, u.; A. Mariño Camargo; J.J. Olaya Flórez: Magnetrón Desbalanceado: Configuración del campo magnético y su correlación con el campo de 2 espiras concéntricas. Rev. Acad. Colomb. Cienc. 36 (138): 37-44, 2012. ISSN 0370-3908.
It shows a process for overlap signals separation by fitting to Gaussians, with aid of Excel pro-... more It shows a process for overlap signals separation by fitting to Gaussians, with aid of Excel pro- gram. This process was applied to quantitative determination of the high current density electro plating Zn-Ni alloys, obtained by Differential Pulse Polarography DPP.
2011 VII Southern Conference on Programmable Logic (SPL), 2011
Abstract Optical Transport Networks (OTN) have emerged as a key enabler to increase the capacity ... more Abstract Optical Transport Networks (OTN) have emerged as a key enabler to increase the capacity of current telecommunication infrastructure. ITU-T Recommendation G. 709 describes these networks by defining a flexible frame structure capable of carrying ...
... after MeV Ion-Induced Shape Deformation * Ulises Morales1, Rosalba Castañeda-Guzmán2, Santiag... more ... after MeV Ion-Induced Shape Deformation * Ulises Morales1, Rosalba Castañeda-Guzmán2, Santiago Jesús Pérez-Ruiz2, Juan-Carlos Cheang-Wong1 ... The studied sam-ples are mounted on a 240 kHz PZT or a 5 MHz ultra-sonic transducer (GE Inspection Technologies). ...
Cobalt oxide and cobalt oxide–silver selective surfaces were prepared in a galvanostatic mode by ... more Cobalt oxide and cobalt oxide–silver selective surfaces were prepared in a galvanostatic mode by means an electrodeposition bath, using different deposition times, on stainless steel substrates. Later, the roughness factor of the selective surfaces, were determined in order to establish one relation with the electrodeposition time and the solar absorptance of the black cobalt and black cobalt–silver coatings.
The surface oxidation of ruthenium catalysts with different roughness factor values has been anal... more The surface oxidation of ruthenium catalysts with different roughness factor values has been analyzed. It is shown that electro formation of oxidized species on the exposed surface of ruthenium is strongly affected by the rougher characteristics of the surface. This effect has been explained through the addition and removal of protons to and from the oxidized species.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2008
Colloidal silica particles are being intensively studied due to their potential applications in c... more Colloidal silica particles are being intensively studied due to their potential applications in catalysis, intelligent materials, optoelectronic devices and coating technology. For this work, spherical sub-micrometer-sized silica particles were prepared by the Stö ber process and deposited onto silicon wafers. The samples were then irradiated at room temperature with Si ions at 8 MeV and fluences up to 5 Â 10 15 Si/cm 2 , under different angles h, ranging from 15°to 75°with respect to the sample normal. The size, size distribution and shape of the silica particles were determined using scanning electron microscopy. After the Si irradiation the as-prepared spherical silica particles turned into ellipsoidal particles, as a result of the increase of the particle dimension perpendicular to the ion beam and a decrease in the direction parallel to the ion beam. This effect increases with the ion fluence, and the dependence of the deformation rate on the irradiation angle is discussed.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2006
Spherical sub-micrometer-sized silica particles were prepared by the Stö ber process, from a reac... more Spherical sub-micrometer-sized silica particles were prepared by the Stö ber process, from a reaction mixture containing tetraethoxysilane, ammonia and ethanol, and deposited into silicon wafers. The samples were then irradiated at room temperature with 4 MeV Si, Ti, Pt or Au ions at a fluence of 4 · 10 15 ions/cm 2 , under an angle of 49°with respect to the sample surface. The size, size distribution and shape of the silica particles were determined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). After the irradiation the spherical silica particles can be turned into ellipsoidal particles, as a result of the increase of the particle dimension perpendicular to the ion beam and a decrease in the direction parallel to the ion beam. This effect increases with the ion fluence and depends on the electronic stopping power of the impinging ion. For the series of 4 MeV ions we used in this work a relative transverse diameter change of 17% per 1 keV/nm was obtained and it seems that no threshold for the electronic energy loss exists.
Spherical submicrometer-sized silica particles were prepared by the Stöber process, from a reacti... more Spherical submicrometer-sized silica particles were prepared by the Stöber process, from a reaction mixture containing tetraethoxysilane, ammonia and ethanol, and deposited onto silicon wafers. While the properties of these SiO2 particles depend on their size, size distribution and shape, monodisperse spherical particles were obtained with a narrow size distribution. The samples were then irradiated at room temperature with Si ions
Page 1. Energy-dependent Deformation of Colloidal Silica Nanoparticles under Room Temperature Irr... more Page 1. Energy-dependent Deformation of Colloidal Silica Nanoparticles under Room Temperature Irradiation with MeV Si Ions Juan-Carlos Cheang-Wong a , Ulises Morales, Eder Reséndiz, and Alejandra López-Suárez Instituto ...
Pt nanoparticles were obtained via the thermal decomposition of (NH 4 ) 2 [PtCl 4 ] (diammonium t... more Pt nanoparticles were obtained via the thermal decomposition of (NH 4 ) 2 [PtCl 4 ] (diammonium tetrachloroplatinate) by heating from room temperature to 760°C. The thermal decomposition process was analyzed using thermogravimetric analysis (TGA) and differential thermal analysis (DTA), X-ray thermodiffraction and infrared spectroscopy. The size and structure of the platinum particles were analyzed using transmission electron microscopy (TEM). The electrochemical activity of Pt particles was assessed by cyclic voltammetry in 0.5 M H 2 SO 4 . The TGA and DTA results suggested that the thermal decomposition of the precursor proceeded in two stages: loss of NH 4 Cl at *300°C, followed by loss of NH 4 Cl and Cl 2 at *372°C. Metallic Pt particles were then produced at temperatures of 372°C and above. At 760°C, the mean ± SD size of the Pt particles was (4.1 ± 1.6) nm, as determined from TEM measurements. In cyclic voltammetry (CV) measurements, an electrode comprised of glassy carbon and Pt particles in 0.5 M H 2 SO 4 exhibited behavior similar to that observed using a polycrystalline Pt electrode.
Corrosion resistance of coatings obtained by sputtering a chromium target were evaluated. The fil... more Corrosion resistance of coatings obtained by sputtering a chromium target were evaluated. The films were deposited on substrates of disk-shaped AISI H13 steel. By means of potentiodynamic polarization curves were able to determine the current density vs. potential for the coated and uncoated substrate and the difference in the corrosion potential Ecorr. All sam- ples with coating showed an increase in Ecorr respect to substrate. The electrochemical tests were conducted in an electrolytic solution of 3% NaCl
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