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Polyaniline (PANI) has recently gained great attention due to its outstanding electrical properties and ease of processability; these characteristics make it ideal for the manufacturing of polymer blends. In this study, the processing and piezoresistive characterization of polymer composites resulting from the blend of PANI with ultra-high molecular weight polyethylene (UHMWPE) in different weight percentages (wt %) is reported. The PANI/UHMWPE composites were uniformly homogenized by mechanical mixing and the pellets were manufactured by compression molding. A total of four pellets were manufactured, with PANI percentages of 20, 25, 30 and 35 wt %. Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to confirm the effective distribution of PANI and UHMWPE particles in the pellets. A piezoresistive characterization was performed on the basis of compressive forces at different voltages; it was found that the error metrics of hysteresis and drift were influenced by the operating voltage. In general, larger voltages lowered the error metrics, but a reduction in sensor sensitivity came along with voltage increments. In an attempt to explain such a phenomenon, the authors developed a microscopic model for the piezoresistive response of PANI composites, aiming towards a broader usage of PANI composites in strain/stress sensing applications as an alternative to carbonaceous materials.
Andrés Felipe Cruz-Pacheco; Leonel Paredes-Madrid; Jahir Orozco; Jairo Alberto Gómez-Cuaspud; Carlos R. Batista-Rodríguez; Carlos Andrés Palacio Gómez. Assessing the Influence of the Sourcing Voltage on Polyaniline Composites for Stress Sensing Applications. Polymers 2020, 12, 1164 .
AMA StyleAndrés Felipe Cruz-Pacheco, Leonel Paredes-Madrid, Jahir Orozco, Jairo Alberto Gómez-Cuaspud, Carlos R. Batista-Rodríguez, Carlos Andrés Palacio Gómez. Assessing the Influence of the Sourcing Voltage on Polyaniline Composites for Stress Sensing Applications. Polymers. 2020; 12 (5):1164.
Chicago/Turabian StyleAndrés Felipe Cruz-Pacheco; Leonel Paredes-Madrid; Jahir Orozco; Jairo Alberto Gómez-Cuaspud; Carlos R. Batista-Rodríguez; Carlos Andrés Palacio Gómez. 2020. "Assessing the Influence of the Sourcing Voltage on Polyaniline Composites for Stress Sensing Applications." Polymers 12, no. 5: 1164.
The accurate determination of specific tumor markers associated with cancer with non-invasive or minimally invasive procedures is the most promising approach to improve the long-term survival of cancer patients and fight against the high incidence and mortality of this disease. Quantification of biomarkers at different stages of the disease can lead to an appropriate and instantaneous therapeutic action. In this context, the determination of biomarkers by electrochemical biosensors is at the forefront of cancer diagnosis research because of their unique features such as their versatility, fast response, accurate quantification, and amenability for multiplexing and miniaturization. In this review, after briefly discussing the relevant aspects and current challenges in the determination of colorectal tumor markers, it will critically summarize the development of electrochemical biosensors to date to this aim, highlighting the enormous potential of these devices to be incorporated into the clinical practice. Finally, it will focus on the remaining challenges and opportunities to bring electrochemical biosensors to the point-of-care testing.
Jennifer Quinchia; Danilo Echeverri; Andrés Felipe Cruz-Pacheco; María Elena Maldonado; Jahir Orozco. Electrochemical Biosensors for Determination of Colorectal Tumor Biomarkers. Micromachines 2020, 11, 411 .
AMA StyleJennifer Quinchia, Danilo Echeverri, Andrés Felipe Cruz-Pacheco, María Elena Maldonado, Jahir Orozco. Electrochemical Biosensors for Determination of Colorectal Tumor Biomarkers. Micromachines. 2020; 11 (4):411.
Chicago/Turabian StyleJennifer Quinchia; Danilo Echeverri; Andrés Felipe Cruz-Pacheco; María Elena Maldonado; Jahir Orozco. 2020. "Electrochemical Biosensors for Determination of Colorectal Tumor Biomarkers." Micromachines 11, no. 4: 411.
Nanoparticles of Ce1‐xPrxO2 (X: 0.6 and 0.8), were synthesized by the combustion method using citric acid (CA) as chelating and fuel agent. The X‐ray diffraction patterns and Rietveld refinements confirm that samples shown a single phase in a cubic fluorite structure, with an increase in the lattice parameter as a function of Pr concentration. The crystallite size domains obtained by the Scherrer formula, confirm values around 10 and 37 nm. The scanning electron microscopy (SEM) images, show that the solids are composed of dense heterogeneous aggregates. The X‐ray photoelectron spectroscopy (XPS), reveals that oxides are composed of cerium and praseodymium cations in oxidation states 4+ and 3+ respectively. The TPR‐H2 profiles indicate that cerium and praseodymium cations present in the obtained systems are completely reduced to Ce3+ and Pr3+ at temperatures above 790 °C. The impedance spectroscopy data at room temperature showed that the conduction processes for the two systems take place at the grain boundaries. The Ce0.2Pr0.8O2 system offer lower resistance, due to the high amount of Pr3+ ions inserted in the structure and the high amount of oxygen vacancies formed in the synthesis process. This article is protected by copyright. All rights reserved.
Andrés F. Cruz‐Pacheco; Jairo Alberto Gómez Cuaspud; Carlos A. Parra Vargas; Juan B. Carda Castello. Effect of Pr on the electrical and chemical properties of cerium oxide prepared by combustion method. International Journal of Applied Ceramic Technology 2019, 16, 2482 -2492.
AMA StyleAndrés F. Cruz‐Pacheco, Jairo Alberto Gómez Cuaspud, Carlos A. Parra Vargas, Juan B. Carda Castello. Effect of Pr on the electrical and chemical properties of cerium oxide prepared by combustion method. International Journal of Applied Ceramic Technology. 2019; 16 (6):2482-2492.
Chicago/Turabian StyleAndrés F. Cruz‐Pacheco; Jairo Alberto Gómez Cuaspud; Carlos A. Parra Vargas; Juan B. Carda Castello. 2019. "Effect of Pr on the electrical and chemical properties of cerium oxide prepared by combustion method." International Journal of Applied Ceramic Technology 16, no. 6: 2482-2492.
The coating of polymeric substrate polyetheretherketone (PEEK) with silver nanoparticles (AgNPs) was carried out by a wet chemical route at room temperature. The coating process was developed from the Tollens reagent and D-glucose as reducing agent. The resulting composite exhibited antimicrobial activity. The PEEK films were coated with a single layer and two layers of silver nanoparticles in various concentrations. The crystallographic properties of the polymer and the silver nanoparticles were analyzed by X-ray diffraction (XRD). Fourier transform infrared spectra (FTIR) show the interaction between the silver nanoparticles with the polymeric substrate. Transmission electron microscope (TEM) images confirmed the obtaining of metallic nanoparticles with average sizes of 25 nm. It was possible to estimate the amount of silver deposited on PEEK with the help of thermogravimetric analysis. The morphology and shape of the AgNPs uniformly deposited on the PEEK films was ascertained by the techniques of scanning electron microscopy (SEM) and atomic force microscopy (AFM), evidencing the increase in the amount of silver by increasing the concentration of the metal precursor. Finally, the antibacterial activity of the films coated with Ag in Escherichia coli, Serratia marcescens and Bacillus licheniformis was evaluated, evidencing that the concentration of silver is crucial in the cellular replication of the bacteria.
Andrés Felipe Cruz-Pacheco; Deysi Tatiana Muñoz-Castiblanco; Jairo Alberto Gómez Cuaspud; Leonel Paredes-Madrid; Carlos Arturo Parra Vargas; José Jobanny Martínez Zambrano; Carlos Andrés Palacio Gómez. Coating of Polyetheretherketone Films with Silver Nanoparticles by a Simple Chemical Reduction Method and Their Antibacterial Activity. Coatings 2019, 9, 91 .
AMA StyleAndrés Felipe Cruz-Pacheco, Deysi Tatiana Muñoz-Castiblanco, Jairo Alberto Gómez Cuaspud, Leonel Paredes-Madrid, Carlos Arturo Parra Vargas, José Jobanny Martínez Zambrano, Carlos Andrés Palacio Gómez. Coating of Polyetheretherketone Films with Silver Nanoparticles by a Simple Chemical Reduction Method and Their Antibacterial Activity. Coatings. 2019; 9 (2):91.
Chicago/Turabian StyleAndrés Felipe Cruz-Pacheco; Deysi Tatiana Muñoz-Castiblanco; Jairo Alberto Gómez Cuaspud; Leonel Paredes-Madrid; Carlos Arturo Parra Vargas; José Jobanny Martínez Zambrano; Carlos Andrés Palacio Gómez. 2019. "Coating of Polyetheretherketone Films with Silver Nanoparticles by a Simple Chemical Reduction Method and Their Antibacterial Activity." Coatings 9, no. 2: 91.
Karen Nayib Martínez-González; Universidad Pedagógica Y Tecnológica De Colombia; Andrés Felipe Cruz-Pacheco; Jairo Alberto Gómez Cuaspud; Carlos Arturo Parra Vargas. Structural and Magnetic Evaluation of the CaTi1- xMxO3 (M = Dy, Ho, Gd) (x = 0.5) System. Revista ION 2018, 31, 81 -88.
AMA StyleKaren Nayib Martínez-González, Universidad Pedagógica Y Tecnológica De Colombia, Andrés Felipe Cruz-Pacheco, Jairo Alberto Gómez Cuaspud, Carlos Arturo Parra Vargas. Structural and Magnetic Evaluation of the CaTi1- xMxO3 (M = Dy, Ho, Gd) (x = 0.5) System. Revista ION. 2018; 31 (1):81-88.
Chicago/Turabian StyleKaren Nayib Martínez-González; Universidad Pedagógica Y Tecnológica De Colombia; Andrés Felipe Cruz-Pacheco; Jairo Alberto Gómez Cuaspud; Carlos Arturo Parra Vargas. 2018. "Structural and Magnetic Evaluation of the CaTi1- xMxO3 (M = Dy, Ho, Gd) (x = 0.5) System." Revista ION 31, no. 1: 81-88.
Los Sensores de Fuerza Resistivos (FSRs) despliegan cantidades considerables de histéresis y de error de repetitividad que inhiben su uso en aplicaciones que requieren lecturas de fuerza de alta precisión. En este trabajo se presenta la caracterización y modelado de histéresis del sensor de presión Tekscan A201-1 empleando la función Operador de Preisach (OP). Con el fin de compensar la histéresis durante el funcionamiento del sensor, el OP inverso se halló numéricamente sobre la base del algoritmo de coincidencia más cercana (CMA). Se construyó un banco de pruebas, capaz de manejar dieciséis sensores simultáneamente, lo que permitió la caracterización y posterior prueba del CMA. Los perfiles de fuerza de agarre se aplicaron a los sensores durante la prueba y los resultados experimentales mostraron una reducción considerable del error de estimación de la fuerza en comparación con el método de regresión lineal propuesto por el fabricante. Estos resultados abren el camino para un uso más amplio de los FSRs en aplicaciones con exigentes requisitos de precisión. Finalmente, un modelo de sensor generalizado para compensación de histéresis que simplifica la obtención de los parámetros PO, es presentado.
Leonel Paredes-Madrid; Arnaldo Matute; Andrés F. Cruz-Pacheco; Carlos A. Parra Vargas; Elkin Iván Gutiérrez Veláquez. Experimental characterization, modeling and compensation of hysteresis in force sensing resistors. DYNA 2018, 85, 191 -198.
AMA StyleLeonel Paredes-Madrid, Arnaldo Matute, Andrés F. Cruz-Pacheco, Carlos A. Parra Vargas, Elkin Iván Gutiérrez Veláquez. Experimental characterization, modeling and compensation of hysteresis in force sensing resistors. DYNA. 2018; 85 (205):191-198.
Chicago/Turabian StyleLeonel Paredes-Madrid; Arnaldo Matute; Andrés F. Cruz-Pacheco; Carlos A. Parra Vargas; Elkin Iván Gutiérrez Veláquez. 2018. "Experimental characterization, modeling and compensation of hysteresis in force sensing resistors." DYNA 85, no. 205: 191-198.
This research describes the synthesis and characterization of the Pr1.5Eu1.5Ba5Cu8O18 system, obtained by the solid-state reaction method. For the synthesis of this material, oxides of Pr6O11, Eu2O3, BaO and CuO were used. The sintering temperature was 900°C. The structural analysis of the synthesized systems was carried out using X-Ray Diffraction (XRD), with a comparison with theoretical patterns and validated with Rietveld refinement analysis, obtaining a type P2mm crystallographic orthorhombic system with a=3.892454Å, b=3.894411Å and c=31.155851Å. The characterization by means of Scanning Electron Microscopy (SEM) let us conclude that the material presents homogeneous granular morphology. Finally, the magnetic response of this material is determined by the magnetization curves as a function of the applied magnetic field 50K and as a function of temperature 2000Oe.
J A Parra-Borda; F G Rojas-Cruz; A F Cruz-Pacheco; S Segura-Peña; C A Parra Vargas. Structural and magnetic analysis of the Pr1.5Eu1.5Ba5Cu8O18system. Journal of Physics: Conference Series 2017, 935, 012005 .
AMA StyleJ A Parra-Borda, F G Rojas-Cruz, A F Cruz-Pacheco, S Segura-Peña, C A Parra Vargas. Structural and magnetic analysis of the Pr1.5Eu1.5Ba5Cu8O18system. Journal of Physics: Conference Series. 2017; 935 (1):012005.
Chicago/Turabian StyleJ A Parra-Borda; F G Rojas-Cruz; A F Cruz-Pacheco; S Segura-Peña; C A Parra Vargas. 2017. "Structural and magnetic analysis of the Pr1.5Eu1.5Ba5Cu8O18system." Journal of Physics: Conference Series 935, no. 1: 012005.
The current work describes the synthesis of Ce1−xPrxO2 (x = 0.0, 0.2, 0.4, 0.6, 0.8) and Pr6O11 systems by the combustion method, using citric acid as chelating agent. The obtained solids after combustion and calcination processes were characterized by thermal analysis (TGA-DTA) and infrared spectroscopy (FT-IR) to evaluate the chemical process during the combustion reaction. The surface area analysis using isotherms of nitrogen adsorption, reveal that all samples exhibit values between 70 and 135 m2 g−1, with a pore volume that allows its classification as mesoporous materials. The structural analysis by X-ray diffraction (XRD) and Rietveld refinement, revealed the obtention of a pure cubic structure Fm3m (225) along all cerium oxide modifications with nanocrystalline domain sizes, except for the praseodymium oxide that shows two crystalline phases in a monoclinic crystalline phase P121/c 1 (14) in the case of Pr6O11 and a cubic phase Fm3m (225) for PrO2 oxide. The oxygen storage capacity measurements performed in all samples, demonstrate that exchange of Ce ions by Pr increases the storage capacity of samples over the reference values in accordance with the synthesis method. The characterization by high-resolution transmission electron microscopy, confirmed that the solids are composed by nanometric aggregates with d spacing between 0.29 and 0.31 nm along main diffraction signals, in accordance with the experimental XRD results. Finally, the magnetic characterization in a ZFC configuration and a M-H mode, shows a strong paramagnetic behavior in all systems except in CeO2 oxide, which exhibited a prevalent diamagnetic behavior.
A. F. Cruz Pacheco; Jairo Alberto Gómez Cuaspud; C. A. Parra Vargas; J. B. Carda Castello. Combustion synthesis, structural and magnetic characterization of Ce1−xPrxO2 system. Journal of Materials Science: Materials in Electronics 2017, 28, 16358 -16365.
AMA StyleA. F. Cruz Pacheco, Jairo Alberto Gómez Cuaspud, C. A. Parra Vargas, J. B. Carda Castello. Combustion synthesis, structural and magnetic characterization of Ce1−xPrxO2 system. Journal of Materials Science: Materials in Electronics. 2017; 28 (21):16358-16365.
Chicago/Turabian StyleA. F. Cruz Pacheco; Jairo Alberto Gómez Cuaspud; C. A. Parra Vargas; J. B. Carda Castello. 2017. "Combustion synthesis, structural and magnetic characterization of Ce1−xPrxO2 system." Journal of Materials Science: Materials in Electronics 28, no. 21: 16358-16365.
This paper report the synthesis, characterization and magnetic evaluation of Ce0.6Pr0.4O2 system using a chemical route that involves the combustion of citrate species. The precursors were characterized by Fourier transform infrared spectroscopy (FTIR), to identify, the main vibrational bands associated with the organic material after combustion process. The structural analysis by X-ray diffraction (XRD) revealed the obtaining of an Fm-3m (225) cubic phase with a particle size around 10nm. Finally, the measurement of the magnetization as a function of applied magnetic field and of susceptibility showed a perfect paramagnetic behaviour.
Andrés Felipe Cruz Pacheco; Jairo Alberto Gómez Cuaspud; C A Parra Vargas. Synthesis, characterization and magnetic evaluation of praseodymium modified cerium oxide. Journal of Physics: Conference Series 2017, 786, 12023 .
AMA StyleAndrés Felipe Cruz Pacheco, Jairo Alberto Gómez Cuaspud, C A Parra Vargas. Synthesis, characterization and magnetic evaluation of praseodymium modified cerium oxide. Journal of Physics: Conference Series. 2017; 786 ():12023.
Chicago/Turabian StyleAndrés Felipe Cruz Pacheco; Jairo Alberto Gómez Cuaspud; C A Parra Vargas. 2017. "Synthesis, characterization and magnetic evaluation of praseodymium modified cerium oxide." Journal of Physics: Conference Series 786, no. : 12023.
This work reports the synthesis and the characterization of six oxides; it is based on Ce1-xPrxO2 (x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) system, which is obtained by the polymerization- combustion technique for potential applications on design of advanced electrodic components, for solid oxide fuel cells (SOFC). Initially the solid precursors are characterized by infrared spectroscopy (FTIR) and thermal analysis (TGA-DTA), allowing to determine the formation of prevalent citrate species and the optimal temperature for the consolidation of the desired crystalline phases. The X-ray diffraction (XRD) and the transmission electron microscopy analysis (TEM) are performed over calcined samples which provided information about the formation of a fluorite phase with grain distribution, surface, textural and morphological properties consistent with the nanometric obtaining crystallites (30nm), it is oriented along the (1 1 1) facet, with d spacings of 0.31nm for the main diffraction signal. These results indicate the effectiveness of the proposed synthesis method for potential applications in the design of advanced anodic materials for solid oxide fuel cells.
Andrés Felipe Cruz Pacheco; Jairo Alberto Gómez Cuaspud; Enrique Vera López. Synthesis of praseodymium doped cerium oxides by the polymerization-combustion method for application as anodic component in SOFC devices. Journal of Physics: Conference Series 2016, 687, 012046 .
AMA StyleAndrés Felipe Cruz Pacheco, Jairo Alberto Gómez Cuaspud, Enrique Vera López. Synthesis of praseodymium doped cerium oxides by the polymerization-combustion method for application as anodic component in SOFC devices. Journal of Physics: Conference Series. 2016; 687 (1):012046.
Chicago/Turabian StyleAndrés Felipe Cruz Pacheco; Jairo Alberto Gómez Cuaspud; Enrique Vera López. 2016. "Synthesis of praseodymium doped cerium oxides by the polymerization-combustion method for application as anodic component in SOFC devices." Journal of Physics: Conference Series 687, no. 1: 012046.