En el Repositorio Escuela Colombiana de Ingeniería Julio Garavito están depositados materiales en formato digital fruto de la producción científica o académica, de esta manera permite almacenar, difundir y preservar información de vital importancia.

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Neural network-based optimization of fibres for seismic retrofitting applications of UHPFRC

Abellán García, Joaquín; DSánchez Díaz, Jairo A.; Ospina Becerra, Victoria Eugenia (Taylor & FrancisReino Unido, 2021)

Ultra-high-performance fibre reinforced concrete (UHPFRC) is an advanced construction material that provides new opportunities in the future of the construction industry around the world. Among those new applications, ...
Development and Characterization of a 3D Printed Cocoa Bean Shell Filled Recycled Polypropylene for Sustainable Composites

Morales, María Alejandra; Maranon, Alejandro; Hernandez, Camilo; PORRAS HOLGUIN, ALICIA (Multidisciplinary Digital Publishing Institute - MDPISuiza, 2021)

Natural filler-based composites are an environmentally friendly and potentially sustainable alternative to synthetic or plastic counterparts. Recycling polymers and using agro-industrial wastes are measures that help to ...
Influence of biodiesel blends produced in Colombia on a Diesel engine

Venegas, Oscar; Mónico Muñoz, Luisa Fernanda (Universiti Malaysai PahangMalasia, 2021)

Diesel engines have dominated the heavy duty and passenger vehicle market in the past 30 years. Consequently, the oil-derived fuels demand and the amount of pollutant emissions have witnessed exponential growth during ...
Performance of Nozzle Steels in Biofuel

Blanco Estupiñan, David Leonardo; Bermudez-Castañeda, Angela; Márquez, Sebastian (Pontificia Universidad JaverianaBogotá (Colombia), 2022)

To evaluate the corrosion resistance of stainless-steel injection nozzles under immersion test in biodiesel and perform electrochemical characterization under HNO3 solutions. Methods and materials: Chemical characterization ...
Corrosion performance of TiAlVN-Ag nanocomposite coating deposited by reactive direct current magnetron sputtering

Giraldo , Francisco; Echavarría, Aida; Bejarano, Gilberto (ElSevierEstados Unidos, 2022)

Surgical devices and tools are manufactured in AISI 420 martensitic stainless steel, due to its hardenability, adequate hardness and acceptable biocompatibility. Nevertheless, many surface modification strategies are being ...

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Neural network-based optimization of fibres for seismic retrofitting applications of UHPFRC
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Abellán García, Joaquín | 2021

Ultra-high-performance fibre reinforced concrete (UHPFRC) is an advanced construction material that provides new opportunities in the future of the construction industry around the world. Among those new applications, rehabilitation, and seismic retrofitting of existing damaged or non-ductile concrete structures can be highlighted. The main objective of this paper is to optimise the hybrid blend of fibres that allows a previously optimised eco-friendly ultra-high performance cementitious paste to achieve the ductility requirements for seismic retrofitting applications at lower costs. To meet this goal, two artificial neural network models (ANNs) were created to predict the energy absorption capacity (g) and maximum post-cracking strain (epc). A total of 50 own experimental campaign data added to 550 published works throughout the world data were used for training purposes by using the R-code language. Once the models were trained and validated, a multi-objective optimisation was used to select the combination of fibres that achieved the limit values of g 50kJ/m3 and epc 0.3% considering cost constraints. The experimentally validated results indicated that the adequate blend of high strength steel micro-fibres and hooked end normal strength steel fibres fulfil the threshold values at a lower cost.

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Development and Characterization of a 3D Printed Cocoa Bean Shell Filled Recycled Polypropylene for Sustainable Composites
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Morales, María Alejandra | 2021

Natural filler-based composites are an environmentally friendly and potentially sustainable alternative to synthetic or plastic counterparts. Recycling polymers and using agro-industrial wastes are measures that help to achieve a circular economy. Thus, this work presents the development and characterization of a 3D printing filament based on recycled polypropylene and cocoa bean shells, which has not been explored yet. The obtained composites were thermally and physically characterized. In addition, the warping effect, mechanical, and morphological analyses were performed on 3D printed specimens. Thermal analysis exhibited decreased thermal stability when cacao bean shell (CBS) particles were added due to their lignocellulosic content. A reduction in both melting enthalpy and crystallinity percentage was identified. This is caused by the increase in the amorphous structures present in the hemicellulose and lignin of the CBS. Mechanical tests showed high dependence of the mechanical properties on the 3D printing raster angle. Tensile strength increased when a raster angle of 0° was used, compared to specimens printed at 90°, due to the load direction. Tensile strength and fracture strain were improved with CBS addition in specimens printed at 90°, and better bonding between adjacent layers was achieved. Electron microscope images identified particle fracture, filler-matrix debonding, and matrix breakage as the central failure mechanisms. These failure mechanisms are attributed to the poor interfacial bonding between the CBS particles and the matrix, which reduced the tensile properties of specimens printed at 0°. On the other hand, the printing process showed that cocoa bean shell particles reduced by 67% the characteristic warping effect of recycled polypropylene during 3D printing, which is advantageous for 3D printing applications of the rPP. Thereby, potential sustainable natural filler composite filaments for 3D printing applications with low density and low cost can be developed, adding value to agro-industrial and plastic wastes.

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Influence of biodiesel blends produced in Colombia on a Diesel engine
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Venegas, Oscar | 2021

Diesel engines have dominated the heavy duty and passenger vehicle market in the past 30 years. Consequently, the oil-derived fuels demand and the amount of pollutant emissions have witnessed exponential growth during the last three decades. Although Diesel engines present the advantage of higher efficiency and, therefore, lower levels of CO2 emissions, they produce high levels of NOX and particulate matter. In order to face these difficulties, the use of alternative fuels started booming in the early 2000s and continue to gain influence today. Biodiesel stands out from the alternative fuels’ selection for its ease of use, production, storage and potential to reduce levels of particles, CO, HC and CO2. The main goal of this research is to experimentally determine the influence of palm oil biodiesel produced in Colombia on a Diesel engine’s behavior in terms of engine performance and pollutant emissions. As different mixtures of commercial Diesel and biodiesel at different operating conditions were tested, the results showed that it is possible to maintain the engine’s performance at acceptable levels and to, in some cases, reduce smoke density and NOX levels.

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Performance of Nozzle Steels in Biofuel
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Blanco Estupiñan, David Leonardo | 2022

To evaluate the corrosion resistance of stainless-steel injection nozzles under immersion test in biodiesel and perform electrochemical characterization under HNO3 solutions. Methods and materials: Chemical characterization of biofuel was performed to analyze its stability. Immersion tests were carried out for 4 months, evaluating 304 stainless steel under 3 different diesel/biofuel mixtures concentrations. Additionally, polarization tests were done using NOx concentrations above the levels measured from engine emissions. Results and discussion: The use of biofuels in Colombia has been largely driven by ethanol production from vegetable sources. Their use brings some advantages related to reducing emissions of particles and toxic gases (mainly aromatic groups, NOx, and CO2). However, degradation of materials can occur when they are in direct contact with biodiesel. Furthermore, solidification into waxes, which leads to plugging of nozzles, has been reported. However, it is unknown whether this influences oxygen diffusion in the solution and, in turn, affects the corrosion resistance of stainless steel. Conclusions: The corrosion resistance of the 304 stainless steel changed under immersion conditions, even though its protective layer was not affected by the NOx concentrations registered in the biofuel mixtures.

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Corrosion performance of TiAlVN-Ag nanocomposite coating deposited by reactive direct current magnetron sputtering
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Giraldo , Francisco | 2022

Surgical devices and tools are manufactured in AISI 420 martensitic stainless steel, due to its hardenability, adequate hardness and acceptable biocompatibility. Nevertheless, many surface modification strategies are being investigated with a view to improving this material by providing it with self-protection against the colonization of bacteria. One such strategy is the use of a TiAlVN-Ag nanocomposite coating to promote bactericidal effect in surgical devices; however, it is necessary to study the electrochemical response of such coatings to aggressive environments that simulate disinfection and sterilization processes. The aim of this work is to study the relationship between the microstructure, chemical phases and the electrochemical and corrosion response of TiAlVN-Ag coating, varying the amount of silver with the target power increase (0, 50, 70, 80 and 100 W). To study the microstructure, chemical phases, scanning and high resolution transmission electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction were used. Roughness, microhardness, residual stresses, qualitative adhesion of coatings were estimated by atomic force microscopy, Knoop indentation, profilometer and Rockwell C indentation, respectively. Electrochemical behavior and corrosion protection of coatings were studied using electrochemical impedance spectroscopy and potentiodynamic polarization. TiAlVN-Ag 50W coating showed an improvement in electrochemical behavior and in protection of the steel against corrosion and exhibiting higher hardness than that of the AISI 420 stainless steel substrates. This coating exhibited a dense microstructure and high crystallinity, indicating that the low Ag content does not affect the insulating nature of the coating matrix.

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Recently Added

Neural network-based optimization of fibres for seismic retrofitting applications of UHPFRC

Development and Characterization of a 3D Printed Cocoa Bean Shell Filled Recycled Polypropylene for Sustainable Composites

Influence of biodiesel blends produced in Colombia on a Diesel engine

Performance of Nozzle Steels in Biofuel

Corrosion performance of TiAlVN-Ag nanocomposite coating deposited by reactive direct current magnetron sputtering

Envíos recientes

Neural network-based optimization of fibres for seismic retrofitting applications of UHPFRC

Development and Characterization of a 3D Printed Cocoa Bean Shell Filled Recycled Polypropylene for Sustainable Composites

Influence of biodiesel blends produced in Colombia on a Diesel engine

Performance of Nozzle Steels in Biofuel

Corrosion performance of TiAlVN-Ag nanocomposite coating deposited by reactive direct current magnetron sputtering

Repositorio Escuela Colombiana de Ingeniería Julio Garavito

Communities in DSpace

Recently Added

Neural network-based optimization of fibres for seismic retrofitting applications of UHPFRC ﻿

Development and Characterization of a 3D Printed Cocoa Bean Shell Filled Recycled Polypropylene for Sustainable Composites ﻿

Influence of biodiesel blends produced in Colombia on a Diesel engine ﻿

Performance of Nozzle Steels in Biofuel ﻿

Corrosion performance of TiAlVN-Ag nanocomposite coating deposited by reactive direct current magnetron sputtering ﻿

Envíos recientes

Neural network-based optimization of fibres for seismic retrofitting applications of UHPFRC

Development and Characterization of a 3D Printed Cocoa Bean Shell Filled Recycled Polypropylene for Sustainable Composites

Influence of biodiesel blends produced in Colombia on a Diesel engine

Performance of Nozzle Steels in Biofuel

Corrosion performance of TiAlVN-Ag nanocomposite coating deposited by reactive direct current magnetron sputtering

Neural network-based optimization of fibres for seismic retrofitting applications of UHPFRC

Development and Characterization of a 3D Printed Cocoa Bean Shell Filled Recycled Polypropylene for Sustainable Composites

Influence of biodiesel blends produced in Colombia on a Diesel engine

Performance of Nozzle Steels in Biofuel

Corrosion performance of TiAlVN-Ag nanocomposite coating deposited by reactive direct current magnetron sputtering