Francy Nelly Jimenez Garcia
@autonoma.edu.co
Departamento de Física y Matemática
Universidad Autónoma de Manizales
Scopus Publications
Scopus Publications
Yenny Marcela Orozco-Ocampo, Daniel Escobar-Rincón, Francy Nelly Jiménez-García, César Augusto Álvarez-Vargas, and Paola Ximena Jaramillo-Gil
Wroclaw Medical University
Nickel-titanium (NiTi) file separation during endodontic treatment is an undesirable event. This phenomenon needs to be understood by knowing the factors influencing fracture in endodontic files. There is a large amount of literature where these factors and their influence have been studied, increasing the knowledge about the mechanisms involved, mainly related to wire technology, file shapes and geometry, operator manipulation, the anatomy of the root canal, and the irrigation and sterilization processes. As many factors are involved, the complexity of the fracture phenomena increases and the isolated correlation of one factor with the file fracture becomes a small part of comprehending the separation phenomena. This thematic review aims to compile important reports from 2014 to 2022 on the factors influencing NiTi file separation. The information obtained was classified into wire technology, file geometry, operational aspects, irrigation and sterilization, and anatomy. For this purpose, the Scopus, Web of Science and ScienceDirect databases were consulted using a search string. Filters were applied to consolidate the final set of relevant papers covering the subject of factors influencing endodontic file separation. It was found that the fracture of NiTi files incorporates different mechanisms that operate simultaneously during the endodontic procedure and strongly affect the instrument performance. The collected information promotes good practices to prevent file separation.
Viviana Londoño Calderón, Rogelio Ospina, Francy Nelly Jiménez García, César Leandro Londoño Calderón, and Elisabeth Restrepo Parra
Elsevier BV
D.M. Gomez Mejia, D.F. Hincapie-Rojas, F.N. Jimenez-Garcia, and César Augusto Alvarez Vargas
Elsevier BV
Juliana Restrepo-Trujillo, Ricardo Moreno-Chuquen, Francy Jiménez-García, Wilfredo Flores, and Harold Chamorro
MDPI AG
This paper develops and analyzes four energy scenarios for Colombia that consider the El Niño phenomenon and the inclusion of renewable energies in the energy generation matrix for the period 2020–2035. A comparative analysis is presented between the results of the different scenarios proposed. The most relevant finding is the use of the reserve margin as an indicator of system reliability. A scenario which included 7214 MW of large-scale non-conventional renewable energy, 10,000 MW of distributed generation, and 12,240 MW of hydroelectric power was assumed, with a reserve margin of over 50%. Additionally, it was found that for the scenarios in which a generation capacity with non-conventional renewable energies of less than 10,000 MW in 2034 was assumed, the reserve margin of the system in the seasons of the El Niño phenomenon will be less than historical records of the system. Alternatively, it was found that the scenarios in which the inclusion of at least 9600 MW of the electric power generation capacity of non-conventional renewable energies proposed by 2034 offer benefits in the reduction in greenhouse gas (GHG) emissions, which contributes to the achievement of the emission reduction objectives of the Paris Agreement.
Carlos Fernando Luna Carlosama, Ricardo Moreno Chuquen, Luis Fernando Mulcue Nieto, and Francy Nelly Jiménez García
MDPI AG
The potential for generating electricity with photovoltaic systems is high in Colombia given its geographical position in the tropic. Some departments in Colombia have low electricity coverage and high rates. In the department of Putumayo there is a low coverage rate and high energy costs, while the solar radiation potential is high. Due to the geographical differences of the Putumayo subregions, the radiation potential for electricity generation is unknown. In addition, in this department the energy tariffs are above the national average. The objective of this paper is to determine the effective potential for solar photovoltaic power generation in the Putumayo department with a detailed methodology considering the information of different remote database and meteorological stations and some technical conditions. It was found that the highest effective solar potential occurs in the Amazon region, and the lowest in the Andean region in the Putumayo. On the other hand, when evaluating electricity consumption and tariffs in the regions, it is concluded that consumption can be satisfied with photovoltaic systems by producing self-generating electricity and distributed generation.
F. N. Jiménez-García, L.R. Giraldo-Torres, and E. Restrepo-Parra
FapUNIFESP (SciELO)
Abstract The effect of growth conditions and post treatments on the properties of calcium phosphate films electrodeposited by a potentiostat of the authors’ design and construction is presented. The electrolyte used was formed with 0.025 M (NH4)H2PO4 and 0.042 M Ca(NO3)2.4H2O, and its pH was kept at 5. A voltametric analysis was performed to determine the necessary potential values to obtain the films. Additionally, the temperature of the electrolyte was varied to determine its influence on the properties of the deposited films. The films were characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The films deposited at -1.4 V and -1.7 V present the brushite phase. The thermal post-treatment favored the formation of octagonal calcium phosphate in amorphous phase, while the basic treatment provided the OH- groups necessary for the formation of hydroxyapatite. The low cost potentiostat implemented presents excellent characteristics for obtaining films with similar characteristics to those obtained with a conventional potentiostat.
Juliana Ortiz-Jimenez, Hector A. Tinoco, Carlos Ivan Cardona, Juan Pablo Gomez, Francy Nelly Jímenez-Garcia, and Samuel Roldan-Restrepo
Trans Tech Publications, Ltd.
Bone tissue is a calcium deposit and supporting structure of the human body, it is exposed to several pathologies that modify its mineral content. To determine these changes, different diagnostic procedures are performed with techniques using invasive ionizing radiation, which are limited by the negative effects in the long term on human health. A methodology is explored that could be applicable in the diagnosis of pathologic variations in bone mineral density, using structural monitoring tools. The proposed technique estimates changes in bone conditions by applying impedance spectroscopy with a tooth-borne piezo-device. Bone-tooth samples were prepared to simulate a section of maxillary bone and subsequently treated with chemical agents, simulating pathologic decalcification. The piezo-device is inserted in the slot of an orthodontic bracket, previously bonded to the crown of the tooth, in order to transmit vibration to surrounding bone. The variations in bone micro-architecture were computed by image processing analyzed with samples prepared in transparent resin, allowing the measurement of morphometry before and after the induced changes in mineral content. Using vibrational bone response, impedance measurements allowed to observe the variations in bone mass as the samples were progressively decalcified. In the 5-50kHz spectrum, it was demonstrated the sensitivity of the electro-mechanical impedance during the bone alteration procedure since the electrical resistance signals of the piezo-device consistently changed in the frequency spectrum (5-50kHz). The piezo-device shows to be sensitive to the changes produced by the bone alterations, which were caused by the stiffness variations made in the sample during the decalcifying. These changes were statistically correlated to demonstrate that in a less invasive way, bone alterations could be monitored from the teeth. This result opens the door to search for a new way to diagnose bone density changes in real applications.
Jose Darío Agudelo-Giraldo, Francy Nelly Jiménez-García, and Elisabeth Restrepo-Parra
MDPI AG
A study of the magnetic behaviour of polycrystalline thin films as a function of their thickness is presented in this work. The grain volume was kept approximately constant in the virtual samples. The model includes the exchange interaction, magneto-crystalline anisotropy, surface anisotropy, boundary grain anisotropy, dipolar interaction, and Zeeman effect. The thickness-dependence of the critical temperature, blocking temperature, and irreversibility temperature are presented. Surface anisotropy exerts a great influence at very low thicknesses, producing a monodomain regime. As the thickness increases, the dipolar interaction produces a coupling in-plane of single domains per grain which favours superparamagnetic states. At higher thicknesses, the effects of the in-plane anisotropy produced by dipolar interaction and surface anisotropy decrease dramatically. As a result, the superparamagnetic states present three-dimensional local anisotropies by the grain.
Francy N. Jimenez, Ligia Beleño, Jairo de J. Agudelo, and Jorge L. Muñiz
SciELO Agencia Nacional de Investigacion y Desarrollo (ANID)
Hugo Hernán Ortiz-Álvarez, Francy Nelly Jiménez-García, Carolina Márquez-Narváez, José Dario Agudelo-Giraldo, and Elisabeth Restrepo-Parra
MDPI AG
In this work, Monte Carlo simulations of magnetic properties of thin films, including the influence of an external pressure, are presented. These simulations were developed using a Hamiltonian composed by terms that represent the exchange interaction, dipolar interaction, Zeeman effect, monocrystalline anisotropy, and pressure influence. The term that represents the pressure influence on the magnetic properties was included, since for many applications, magnetic materials are a part of a multiferroic material together with a piezoelectric or a ferroelectric compound. Initially, the model was developed using generic parameters, in order to probe its suitable performance; after that, parameters were adjusted for simulating thin films of La0.67Sr0.33MnO3, a manganite with several technological applications because its Curie temperature is greater than room temperature. Including the pressure influence, it was observed the formation of several kind of FM/AF configurations as strip, labyrinth, and chess board forms. Furthermore, it was observed that, as the pressure increased, the critical temperature tended to decrease, and this result was in agreement with experimental reports.
Luis Fernando Mulcué-Nieto, Luisa Fernanda Echeverry-Cardona, Alejandra María Restrepo-Franco, Gerardo Andrés García-Gutiérrez, Francy Nelly Jiménez-García, and Llanos Mora-López
Elsevier BV
Juan Fernando Ramirez, Juliana Ortiz, Jorge Andrés Cuellar, Carlos Andrés Naranjo, Francy Nelly Jiménez, and Oscar Moscoso Londoño
IOP Publishing
Abstract Silver nanoparticles have been obtained by colloidal synthesis using two different reducing agents: ascorbic acid and ethylene glycol. The colloids have been characterized by UV-Vis Spectroscopy, atomic absorption and transmission electron microscopy (TEM). The UV-visible spectra show the typical peak with a maximum ranging between 390-420 nm, due to the plasmon resonance of spherical silver nanoparticles. TEM micrographs show non-aggregated spherical silver nanoparticles whit diameters between 30 and 50 nm. The antibacterial effect was tested in three different bacteria cultures: Escherichia coli (gram negative), Staphylococcus epidermidis (gram positive) and dental plaque, which were grown in Mueller-Hinton agar. For comparative purposes the bactericidal effect of silver nitrate was also evaluated. Inhibition index (IIC) was calculated, obtaining satisfactory results for the three kinds of microorganism when silver nanoparticles are used.
J. Restrepo-Trujillo, Ricardo Moreno-Chuquen, and Francy Nelly Jiménez-García
EconJournals
The phenomena of climatic variability such as El Nino affect the expansion planning of electricity supply systems with hydroelectric power plants due to the uncertainty presented in the variables of rainfall patterns, temperature, wind, solar radiation changes, among others. The El Nino affects the electricity generation in Colombia, Venezuela and northwestern Brazil due to severe droughts that reduce water flows in rivers and water volume in dams. While in Peru, Paraguay, Bolivia, Uruguay, Argentina and southern Brazil, causes heavy rains that lead to an increase in reservoirs. Recent findings provide sufficient evidence on how climate change modifies the patterns of duration, frequency and intensity of El Nino and therefore will introduce additional uncertainties to the expansion planning of electricity generation systems in countries that uses predominantly hydroelectric power. The vulnerability of electricity supply systems with a significant participation of hydroelectric power plants in Colombia, Brazil, Ecuador, Peru, Panama, Canada, Norway, Costa Rica and New Zealand is associated with fluctuations in the availability of water resources. This document aims to analyze the current plans for the expansion of electric power generation systems by the aforementioned countries in the context of climate change in medium and long term. Additionally, this document provides a detailed analysis of the situation of electricity supply systems in Colombia.
F. Jiménez-García, Laura R. Giraldo-Torres, B. Segura-Giraldo, A. L. Giraldo-Betancur and J. Muñoz-Saldaña
The effect of growing conditions and post treatments in electrodeposited calcium phosphate films on 316 L stainless steel is presented. The concentration and pH of electrolyte solution and the potential values for the electrodeposition process were determined based on a study of cyclic voltammetry curves. The electrolyte concentration was fixed at 0.025 M ((NH 4 ) H 2 PO 4 ) and 0.042 M (Ca(NO 3 ) 2 .4H 2 O), choosing a pH = 5 as the better condition for the films deposition. In addition, the electrolyte temperature was varied between room temperature and 60°C to determine the influence of this parameter on the deposited films. Films were characterized using Fourier Transform Infrared Spectroscopy, X-ray diffraction and Scanning electron microscopy equipped with energy dispersive spectroscopy. The as deposited films at -1.2 V and -1.7 V exhibit the dicalcium phosphate dihydrate phase (Brushite) while thermal post treatment favor the formation of octacalcium phosphate in amorphous phase, and basic treatment tend to produce the Hydroxyapatite phase. The suggested mechanism for the HAp phase formation, after the basic treatment, consists in providing the necessary OH- groups to complete the synthesis process.
F. N Jiménez-García, B Segura-Giraldo, E Restrepo-Parra, and G.A López-López
SciELO Agencia Nacional de Investigacion y Desarrollo (ANID)
Se prepararon y caracterizaron peliculas de TiO2 sobre sustratos de vidrio por el metodo SILAR (del ingles Successive Ionic Layer Adsorption and Reaction, adsorcion y reaccion ionica en capas sucesivas). La preparacion consistio en una inmersion sucesiva y alternada de los sustratos en una solucion precursora y en agua destilada a 353 K durante 150 ciclos. Se hicieron crecimientos a dos condiciones de la solucion precursora, la que contenia TiCl3 y NH2CONH2: a temperatura ambiente y a 343 K. Despues de los crecimientos, las peliculas se trataron termicamente a 723 K durante dos horas. En relacion con la caracterizacion, las muestras fueron estudiadas empleando XRD, SEM y UV-Vis. Los resultados de la caracterizacion estructural mostraron que las peliculas, en general, presentaron una estructura cristalina amorfa excepto aquellas que crecieron con solucion precursora a 343 K y que fueron tratadas termicamente despues del crecimiento, las que presentaron la fase cristalina anatase. En cuanto a la morfologia, se observo una estructura granular y una distribucion aleatoria tipo flores cuyos tamanos de grano no cambiaron significativamente con el tratamiento termico. El estudio optico se llevo a cabo teniendo en cuenta una transicion indirecta permitida, lo que permitio determinar una energia de la brecha prohibida alrededor de 3.1 eV; este valor, tipico para TiO2, disminuyo con el tratamiento termico, lo que es comun para este tipo de peliculas.
F. N. Jiménez-García, C. L. Londoño-Calderón, D. G. Espinosa-Arbeláez, A. Del Real, and M. E. Rodríguez-García
Springer Science and Business Media LLC
ZnO films were obtained by successive ionic layer adsorption and reaction (SILAR) method from four different substrates: glass microslides, corning glass, quartz and silicon with and without oxide layer. For films deposition, a precursor solution of ZnSO4 was used, complexed with ammonium hydroxide. Prior to the film deposition, wettability of the substrates was analysed using a CCD camera. It was found that the Si without the oxide layer substrate shows hydrophobic behaviour, which makes the films less adherent and not uniform, while in the other substrates, the behaviour was optimal for the growing process. ZnO films grown on glass microslides, corning glass, quartz and Si with oxide layer were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis techniques. According to the XRD patterns, the films were polycrystalline, with hexagonal wurtzite structure and the patterns mentioned showed significant differences in crystallite sizes, microstrain and texture coefficient with respect to the employed substrates. The morphology of the ZnO films constituted by rice-like and flower-like structures shows differences in form and size depending on the substrate. The UV-Vis spectroscopy results show that the substrate did not influence the band gap energy value obtained from films.
F.N. Jiménez-García, D.G. Espinosa-Arbeláez, C. Vargas-Hernández, A. del Real, and M.E. Rodríguez-García
Elsevier BV
Abstract ZnO and ZnMnO thin films were obtained by the successive ionic layer adsorption and reaction (SILAR) method. All thin films were deposited on glass microscope slide. A precursor solution of 0.1 M of ZnCl2 complexed with ammonium hydroxide and water close to boiling point (92 °C) as a second solution was used for the ZnO films. An uncomplexed bath comprised of 0.1 M ZnCl2, 0.1 M MnCl2, and a second solution of 0.1 ml of NH4OH with water close to boiling point was used for the ZnMnO films. The film samples were deposited by the SILAR method and annealed at 200 °C for 15 min. These samples were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (EDS), and Atomic Force Microscope. Atomic absorption was used to determine quantitatively the amount of Mn incorporated into the films. According to the XRD patterns these films were polycrystalline with wurtzite hexagonal structure. The morphology of the ZnO films constituted by rice-like and flower-like structures changed significantly to nanosheet structures with the Mn incorporation. The Mn inclusion in a ZnO structure was less than 4% according to the results from EDS, XRD, and atomic absorption.
C. Vargas-Hernández, F.N. Jiménez-García, J.F. Jurado, and V. Henao Granada
Elsevier BV
ZnO thin films were deposited by successive ionic layer adsorption and reaction (SILAR) method using a zinc nitrate and ammonium bath on glass substrates. The number of employed cycles were 50, 100 and 200. The films were studied by X-ray diffraction (XRD), optical absorption (UV-Vis) and @m-Raman. Structural analysis by XRD shows that the as-deposited ZnO films have high-orientation along c-direction (002). The band gap energy decreases from 3.39 to 3.32eV with number of cycles. By @m-Raman spectroscopy, the principal vibration modes around 435, 550, 579, and 1100cm^-^1 were determined.
C. Vargas-Hernández, F.N. Jiménez-García, J.F. Jurado, and V. Henao Granada
Elsevier BV
ZnO thin films were deposited on amorphous glass substrates using successive ionic layer adsorption and reaction (SILAR). The employed baths were ammonium zincate, with NH"3 and NH"4OH as complex agents and ZnSO"4 and Zn(NO"3)"2 as precursor sources. The comparison between films deposited by three processes was studied by means of X-ray diffraction (XRD), optical absorption, and micro Raman. The band gap is between 3.14 and 3.30eV. By @m-Raman spectroscopy, the principal vibration modes around 435 and 579cm^-^1 were determined in all the films.