Mostrando ítems 1-20 de 46

Analysis of performance, emissions, and lubrication in a spark-ignition engine fueled with hydrogen gas mixtures

Pardo García, Carlos Eduardo; Orjuela Abril, Martha Sofia ; PABON LEON, JHON ANTUNY (Heliyon, 2022-10-26)

Hydrogen is one of the main alternative fuels with the greatest potential to replace fossil fuels due to its renewable and environmentally friendly nature. Due to this, the present investigation aims to evaluate the ...
Analysis of the characteristics of combustion, emissions, and energy efficiency of blends of heptanol with pure diesel fuel in compression ignition engine(Article)

García, C.P; PABON LEON, JHON ANTUNY; FONSECA VIGOYA, MARLEN DEL SOCORRO (Italia, 2021-09)

The objective of this research is to study the influence of the heptanol content in conventional diesel fuel in different proportions for the evaluation of the combustion parameters, emissions, and energy efficiency. For ...
Analysis of the influence of textured surfaces and lubrication conditions on the tribological performance between the compression ring and cylinder liner

Pardo García, Carlos Eduardo; Rojas Suárez, Jhan Piero; Orjuela Abril, Martha Sofia (LubricantsSuiza, 2021-05-06)

The objective of the present investigation is to analyze the tribological performance between the union of the cylinder liner and the compression ring under the influence of surface texturing and different lubrication ...
Analysis of the main labor market indicators by gender in Cúcuta in the period 2010-2017

Marulanda Ascanio, Carolina; Bastos-Osorio, liliana Marcela; Gómez Mina, Lucy; barrientos, ender jose (Mundo FescColombia, 2019-05-30)

The purpose of the research was the analysis through the main labor market indicators by gender in Colombia and in the city of Cúcuta in the 2010-2017 period, through a descriptive and documentary methodology, with which ...
Analysis of the Tribological and Dynamic Characteristics of the Piston Compression Ring Under Different Engine Operating Conditions

Pardo García, Carlos Eduardo; PABON LEON, JHON ANTUNY; FONSECA VIGOYA, MARLEN DEL SOCORRO (International Review of Mechanical EngineeringItalia, 2021)

In this investigation, a study of the tribological and dynamic characteristics present in the compression ring is executed for different engine conditions. A series of numerical simulations has been carried out using the ...
Análisis económico del sector cacaotero en Norte de Santander, Colombia y a nivel internacional

Vásquez Barajas, Eduardo Felipe; Garcia Torres, Nelson Emilio; Bastos-Osorio, liliana Marcela; Lázaro Pacheco, Joordan Mauricio (Revista de Investigación Desarrollo e InnovaciónColombia, 2018-06-01)

El objetivo principal es analizar económicamente el sector cacaotero en Norte de Santander, Colombia y a nivel internacional. El método es deductivo con estudio descriptivo y de campo. Se consultaron fuentes como instituciones ...
Application of neural and bayesian networks in diesel engines under the flaw detection method

Prada Botia, Gaudy Carolina; PABON LEON, JHON ANTUNY; Orjuela Abril, Martha Sofia (Reino Unido, 2021-05-22)

The identification of premature faults in Internal Combustion Engines has become determinant to guarantee suitable operation. Therefore, this study focuses on the implementation of fault diagnostic methodology by using ...
CFD Analysis of the Effect of Dimples and Cylinder Liner Honing Groove on the Tribological Characteristics of a Low Displacement Engine

Orjuela Abril, Martha Sofia ; FONSECA VIGOYA, MARLEN DEL SOCORRO; Pabón León, Jhon (LubricantsSuiza, 2022-04-07)

The contact between the piston rings and the cylinder liner is an interface with a strong influence on the tribological behavior and, therefore, directly affects the useful life of the engine components and fuel consumption. ...
Colombia y el Proyecto Mesoamérica: Fortaleciendo la cooperación internacional en la región

Bastos-Osorio, liliana Marcela; MOGROVEJO ANDRADE, JOHANNA MILENA; PABON LEON, JHON ANTUNY (Revista EspaciosVenezuela, 2018)

Este artículo tiene por finalidad hacer un análisis de la relación entre Colombia y el Proyecto Mesoamérica, haciendo una revisión de lo que inició como un acuerdo político y en lo que se ha reflejado en el fortalecimiento ...
Comparison of lightening costs for reinforced concrete gantry

Prada Botia, Gaudy Carolina; Rojas Suárez, Jhan Piero; Orjuela Abril, Martha Sofia (Journal of Physics: Conference Series, 2019-11-19)

The selection of suitable materials for a construction defines the costs and characteristics that can contribute to the building, being of vital importance to make a correct choice. Lightening is an element to reduce costs ...
Crisis y economía sumergida en Norte de Santander (Colombia)

RAMIREZ ZAMBRANO, JORGE RAUL; MOGROVEJO ANDRADE, JOHANNA MILENA; Bastos-Osorio, liliana Marcela (Revista EspaciosVenezuela, 2018)

El siguiente artículo de investigación tiene por objetivo realizar una estimación subjetiva de las actividades de economía sumergida o economía a la sombra “shadow economy”, para lo cual se parte de la taxonomía diseñada ...
Development of a gravimetric fuel measurement system for the evaluation of engine performance physical parameters

Prada Botia, Gaudy Carolina; Rojas Suárez, J P; Orjuela Abril, M S (Reino Unido, 2021)

This paper presents the implementation and design features of a gravimetric-based fuel consumption system. The proposed system comprises a gravimetric balance with serial output, a fuel pump, and a control valve that are ...
Development of a numerical methodology for evaluating physical properties and technical specifications in thermoelectric devices

Prada Botia, Gaudy Carolina; Rojas Suárez, J P; Orjuela Abril, Martha Sofia (Reino Unido, 2021-06-04)

Typically, the performance evaluation of thermoelectric devices is done using experimental methods and analytical models, which require detailed information on the thermoelectric properties of the materials that make up ...
El diferencial cambiario en la frontera Norte de Santander, Colombia y Venezuela. ¿La economía o la política?

PABON LEON, JHON ANTUNY; Bastos-Osorio, liliana Marcela; MOGROVEJO ANDRADE, JOHANNA MILENA (TendenciasColombia, 2016-09-07)

Se analiza el diferencial cambiario en la frontera Norte de Santander Colombia y Venezuela desde el punto de vista de ambas naciones argumentado en una reflexión teórica. La llamada “frontera más viva de Latinoamérica” ...
Document details - A numerical model for the analysis of the bearings of a diesel engine subjected to conditions of wear and misalignment

Pardo García, Carlos Eduardo; Rojas Suárez, Jhan Piero; Orjuela Abril, Martha Sofia (LubricantsSuiza, 2021-04-09)

In the present work, a numerical model is developed to investigate the influence of wear and misalignment on the bearings of a stationary diesel engine. The model implemented considers the effects of surface wear on the ...
El eslabón perdido de la innovación: Relación Universidad Empresa

Sepúlveda Angarita, Magda Zarela (Revista EspaciosVenezuela, 2017)

El artículo es una reflexión sobre la necesidad mutua de vinculación entre la universidad y la empresa (RUE). Esta articulación ha sido la ruta para alcanzar la innovación empresarial, la competitividad y el desarrollo ...
El estado del desempeño científico en Colombia

RAMIREZ ZAMBRANO, JORGE RAUL; MOGROVEJO ANDRADE, JOHANNA MILENA (Revista EspaciosVenezuela, 2018)

El siguiente artículo tiene por objetivo analizar el estado del desempeño científico en Colombia durante el periodo 2006-2014. El referente teórico seguido es el propuesto por Salmi (2009), y, por Salmi & Altabach (2011). ...
Evaluation of Energy Losses in Auxiliary Systems and Mechanisms Subject to Friction in a Stationary Diesel Engine

Pardo García, Carlos Eduardo; PABON LEON, JHON ANTUNY; FONSECA VIGOYA, MARLEN DEL SOCORRO (International Review of Mechanical EngineeringItalia, 2021)

This research has developed a methodology to estimate energy losses associated with auxiliary systems and mechanisms subject to friction in a stationary diesel engine. The study methodology is based on mathematical models ...
Evaluation of Performance Parameters and Emissions of a Diesel Engine Fueled with Preheated Palm Oil Mill Effluent Biodiesel Blends

Pardo García, Carlos Eduardo; PABON LEON, JHON ANTUNY; FONSECA VIGOYA, MARLEN DEL SOCORRO (International Review of Mechanical EngineeringItalia, 2021)

The current research analyzes the effect of fuel preheating on performance parameters and emission characteristics in a stationary diesel engine fuelled with palm oil mill effluent biodiesel blends. The investigation has ...
Evaluation of the fire resistance of steel-reinforced concretefilled steel tubular columns with a circular cross-section

Rojas Suárez, J P; Pabón León, Jhon Antuny; Orjuela Abril, Martha Sofia (Journal of Physics: Conference SeriesReino Unido, 2022-01-06)

In the present investigation, an analysis of the fire resistance of the steel-reinforced concrete-filled steel tubular columns with circular cross-sections was carried out by means of numerical simulation. The development ...

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Analysis of performance, emissions, and lubrication in a spark-ignition engine fueled with hydrogen gas mixtures
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Pardo García, Carlos Eduardo | 2022-10-26

Hydrogen is one of the main alternative fuels with the greatest potential to replace fossil fuels due to its renewable and environmentally friendly nature. Due to this, the present investigation aims to evaluate the combustion characteristics, performance parameters, emissions, and variations in the characteristics of the lubricating oil. The investigation was conducted in a spark-ignition engine fueled by gasoline and hydrogen gas. Four engine load conditions (25%, 50%, 75%, and 100%) and three hydrogen gas mass concentration conditions (3%, 6%, and 9%) were defined for the study. The investigation results allowed to demonstrate that the injection of hydrogen gas in the gasoline engine causes an increase of 3.2% and 4.0% in the maximum values of combustion pressure and heat release rates. Additionally, hydrogen causes a 2.9% increase in engine BTE. Hydrogen’s more efficient combustion process allowed for reducing CO, HC, and smoke opacity emissions. However, hydrogen gas causes an additional increase of 14.5% and 30.4% in reducing the kinematic viscosity and the total base number of the lubricating oil. In addition, there was evidence of an increase in the concentration of wear debris, such as Fe and Cu, which implies higher rates of wear in the engine’s internal components.

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Analysis of the characteristics of combustion, emissions, and energy efficiency of blends of heptanol with pure diesel fuel in compression ignition engine(Article)
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García, C.P | 2021-09

The objective of this research is to study the influence of the heptanol content in conventional diesel fuel in different proportions for the evaluation of the combustion parameters, emissions, and energy efficiency. For the above, three heptanol blends identified as HP4%, HP8%, and HP16% have been used with a percentage of heptanol of 4%, 8%, and 16%, respectively. The tests have beencarried out on a single-cylinder stationary diesel engine at a constant load (9 Nm) and a rotational speed of 2800 rpm, 3200 rpm, and 3600 rpm. The results show that the percentage of heptanol causes an increase in the maximum values of the pressure in the combustion chamber and the heat release rate. In general, the presence of heptanol in conventional diesel produces an increase of 3.9% and 4.8% in the maximum values of these parameters. Additionally, the HP4%, HP8%, and HP16% heptanol blends allow reducing CO2, NOx, and smoke opacity emissions by 11.7%, 6.7%, and 37.1%, respectively. Due to the closeness of the physicochemical properties between the blends of heptanol and conventional diesel, a similarity between the energy and exergy performance between both fuels has been obtained. The above demonstrates the potential of heptanol to be used as a renewable fuel without the need for modifications to the engine. In addition, they have the ability to reduce NOx emissions, which is a problem in various types of biodiesel.

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Analysis of the influence of textured surfaces and lubrication conditions on the tribological performance between the compression ring and cylinder liner
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Pardo García, Carlos Eduardo | 2021-05-06

The objective of the present investigation is to analyze the tribological performance between the union of the cylinder liner and the compression ring under the influence of surface texturing and different lubrication boundary conditions. The analysis is carried out by developing a numerical model, which involves hydrodynamic pressure, lubrication film thickness, textured surface, dynamic forces, and lubrication boundary conditions (starved lubrication and fully flooded lubrication). MATLAB® software (The MathWorks Inc., Natick, MA, USA) is used to solve the equations developed. The results show that the application of a textured surface on the cylinder liner allows obtaining a reduction of 20% and 5% in the asperity contact force and in the total friction force. Additionally, the textured surface allows for a 4% increase in MOFT. In this way, it is possible to reduce the power loss. The implementation of a boundary condition of fully flooded lubrication produces an overestimation in the total friction force due to the greater prominence of the lubrication film. Implementing a textured surface in the ring profile is an alternative way to reduce power loss. The results show that this alternative allows an 8% reduction in power loss.

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Analysis of the main labor market indicators by gender in Cúcuta in the period 2010-2017
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Marulanda Ascanio, Carolina | 2019-05-30

The purpose of the research was the analysis through the main labor market indicators by gender in Colombia and in the city of Cúcuta in the 2010-2017 period, through a descriptive and documentary methodology, with which the different indexes were analyzed and described. in order to be able to establish criteria of how the differences are by gender and among others as a global participation rate that expresses the pressure of the population in the labor market. This research concludes that the female population is higher than the male population in the entire period studied and their participation in the labor market is lower, in addition, the unemployment rate is higher in this period and the rate of employed persons is lower.

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Analysis of the Tribological and Dynamic Characteristics of the Piston Compression Ring Under Different Engine Operating Conditions
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Pardo García, Carlos Eduardo | 2021

In this investigation, a study of the tribological and dynamic characteristics present in the compression ring is executed for different engine conditions. A series of numerical simulations has been carried out using the OpenFOAM software for the study. The simulation conditions have been based on the parameters measured on a diesel engine test bench. Different ranges of rotation speed, load, and lubrication oil temperature have been established for the analysis. The results show that the parameters of rotation speed and engine load significantly influence the tribological and dynamic conditions of the piston compression ring. An increase of 425 rpm and 136 Nm in the rotational speed and load of the engine causes an increase of 13% and 34% in the power loss due to friction. The Top Dead Center and the Bottom Dead Center are the locations most prone to experience critical wear and tear. Increasing the lubricating oil temperature increases the maximum friction force by 9%. In general, the proposed methodology allows for establishing a direct relationship between the operating conditions and the tribological characteristics in the compression ring that directly affect the efficiency and useful life of the engine.

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Análisis económico del sector cacaotero en Norte de Santander, Colombia y a nivel internacional
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Vásquez Barajas, Eduardo Felipe | 2018-06-01

El objetivo principal es analizar económicamente el sector cacaotero en Norte de Santander, Colombia y a nivel internacional. El método es deductivo con estudio descriptivo y de campo. Se consultaron fuentes como instituciones del cacao en Colombia y a nivel internacional, así como fuentes documentales de organismos estatales y privados. En cuanto a resultados y conclusiones se tiene que en Norte de Santander, así como en Colombia, se requiere aumentar la producción de cacao y su tecnificación en el cultivo para aprovechar la alta demanda internacional de cacao y sus derivados, así como los buenos precios para ampliar su participación internacional, tomando la ventaja diferencial del cacao fino y de aroma. Lo anterior debe ir acompañado de la generación de valor agregado, competitividad, aprovechamiento de los tratados comerciales vigentes en Colombia y la proyección del cacao como cultivo clave del postconflicto colombiano.

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Application of neural and bayesian networks in diesel engines under the flaw detection method
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Prada Botia, Gaudy Carolina | 2021-05-22

The identification of premature faults in Internal Combustion Engines has become determinant to guarantee suitable operation. Therefore, this study focuses on the implementation of fault diagnostic methodology by using advanced algorithms such as Back Propagation neural networks and Bayesian networks. Results indicated that the proposed methodology serves as a robust tool to identify different fault conditions in a wide operational spectrum with an reliability of nearly 73%. Moreover, the Backpropagation network diagnostic methodology presented an reliability of 18%, which is 3% higher than Bayesian networks. Overall, the implemented methodology counterbalanced interference conditions and noise signals while providing versatility to operate for different types of engines. In conclusion, this study can be extrapolated to different fields of physics to assist in identifying flaws in experimental test benches.

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CFD Analysis of the Effect of Dimples and Cylinder Liner Honing Groove on the Tribological Characteristics of a Low Displacement Engine
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Orjuela Abril, Martha Sofia | 2022-04-07

The contact between the piston rings and the cylinder liner is an interface with a strong influence on the tribological behavior and, therefore, directly affects the useful life of the engine components and fuel consumption. Due to this importance, the present investigation carried out an analysis of the effects of dimples and the honing groove in the cylinder liner on the tribological characteristics. A tribological model was developed to study the friction forces, minimum film thickness, and friction coefficient for the present investigation. Similarly, a computational fluid dynamics model was built to determine the dynamic movement of the piston. The validation of the numerical model showed a close similarity with the real behavior of the engine, obtaining an average relative error of 14%. The analysis of the results showed that a 3% increase in dimples’ density leads to a 3.79% increase in the minimum lubricant film and a 2.76% decrease in friction force. Additionally, it was shown that doubling the radius and depth of the dimple produces an increase of 3.86% and 1.91% in the thickness of the lubrication film. The most suitable distribution of the dimples on the surface of the cylinder liner corresponds to a square array. In general, the application of dimples and honing grooves in the cylinder liner are promising alternatives to reduce energy losses and minimize wear of engine components.

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Colombia y el Proyecto Mesoamérica: Fortaleciendo la cooperación internacional en la región
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Bastos-Osorio, liliana Marcela | 2018

Este artículo tiene por finalidad hacer un análisis de la relación entre Colombia y el Proyecto Mesoamérica, haciendo una revisión de lo que inició como un acuerdo político y en lo que se ha reflejado en el fortalecimiento de la cooperación internacional de Colombia con los países centroamericanos. La metodología constituye una investigación aplicada de tipo descriptivo-analítico. El resultado de la investigación es que Colombia entre 2010 a 2017 ha estado fortaleciendo la cooperación sur-sur con los países centroamericanos a través del proyecto Mesoamérica.

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Comparison of lightening costs for reinforced concrete gantry
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Prada Botia, Gaudy Carolina | 2019-11-19

The selection of suitable materials for a construction defines the costs and characteristics that can contribute to the building, being of vital importance to make a correct choice. Lightening is an element to reduce costs and optimize resources, adding a better index of resistance against earthquakes, being of vital importance the good choice of this: concrete, clay or EPS. In this investigation a comparison of costs and incidence of the three types of lighteners that are used in the construction of three levels houses with reinforced concrete portico based on the requirements of NSR-10 was made by means of statistical samples/data, graphs and tables of data analysis, on the quotations and information collected from different studies on lightening costs in structures.

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Crisis y economía sumergida en Norte de Santander (Colombia)
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RAMIREZ ZAMBRANO, JORGE RAUL | 2018

El siguiente artículo de investigación tiene por objetivo realizar una estimación subjetiva de las actividades de economía sumergida o economía a la sombra “shadow economy”, para lo cual se parte de la taxonomía diseñada por Feige (1990), la metodología parte del diseño de una encuesta que permite hacer conmensurable las percepciones ciudadanas de los habitantes de Norte de Santander (Colombia) que viven en los municipios de Cúcuta, Villa del Rosario, Los Patios y Puerto Santander.

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Development of a gravimetric fuel measurement system for the evaluation of engine performance physical parameters
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Prada Botia, Gaudy Carolina | 2021

This paper presents the implementation and design features of a gravimetric-based fuel consumption system. The proposed system comprises a gravimetric balance with serial output, a fuel pump, and a control valve that are integrated into a complete engine test bench via Arduino UNO®. The study implements an instrumentation methodology to minimize measurement disturbance and error propagation, which represents a major concern in engine experimental testing. Moreover, an interactive virtual environment is developed to reinforce user interaction via LabView™. Results demonstrated that the proposed measurement system features robust and reliable operation while maintaining negligible disturbance and overall uncertainty ranging from 0.010-0.23 g/s. Additionally, it was evidenced that the measurement system allows the analysis of key parameters to evaluate engine performance. The study of the fuels blends shows that the ethanol content causes a 6.8% increase in brake specific fuel consumption and a 4% decrease in the brake thermal efficiency. Due to the low cost of the developed measurement system can be easily adapted to test bench laboratories to promote a better learning process and in industrial sectors for better energy management.

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Development of a numerical methodology for evaluating physical properties and technical specifications in thermoelectric devices
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Prada Botia, Gaudy Carolina | 2021-06-04

Typically, the performance evaluation of thermoelectric devices is done using experimental methods and analytical models, which require detailed information on the thermoelectric properties of the materials that make up the thermoelectric devices. However, this type of information is generally not available. Due to this situation, the present investigation seeks to develop a numerical methodology to determine the performance of thermoelectric devices, using technical reference specifications that are normally provided by the manufacturer, such as maximum current, maximum voltage, maximum temperature difference, and efficiency. The numerical model is made up of a series of equations based on thermoelectric phenomena, which generates a contribution in the area of physics. The results obtained are validated through experimental comparisons and the technical data of the thermoelectric devices. The comparison between the different results shows a maximum error of 5%. Therefore, the developed methodology is considered a robust tool for the realistic analysis of the performance of thermoelectric generators and thermoelectric coolers. The foregoing will allow massive use of this type of device in industrial applications and its commercial accessibility.

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El diferencial cambiario en la frontera Norte de Santander, Colombia y Venezuela. ¿La economía o la política?
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PABON LEON, JHON ANTUNY | 2016-09-07

Se analiza el diferencial cambiario en la frontera Norte de Santander Colombia y Venezuela desde el punto de vista de ambas naciones argumentado en una reflexión teórica. La llamada “frontera más viva de Latinoamérica” presenta alta intensidad de comercio transfronterizo con un alto arraigo histórico que hace interdependientes ambas regiones. Su estudio es importante, la visión de la economía venezolana ha producido desajustes que se han trasladado a una región donde existe una economía de mercado que se ha afectado por el diferencial cambiario propiciando el contrabando y otras modalidades nuevas como el “bachaqueo”, donde comercian con dos o tres productos y los maleteros que transportan a través del río. Allí no existe consenso en cuanto a las causas del diferencial cambiario, para unos es consecuencia del mercado y de los desequilibrios originados por las políticas del gobierno venezolano, para otros es consecuencia de la especulación y de las mafias de la frontera. Ante esta realidad con visiones antagónicas, concuerda la proposición de la asimetría complementaria de los estados colindantes, se considera que priva el matiz político venezolano sobre la economía y existe un caos organizado en el manejo del diferencial cambiario beneficiándose los diferentes actores aunque se exprese lo contrario.

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Document details - A numerical model for the analysis of the bearings of a diesel engine subjected to conditions of wear and misalignment
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Pardo García, Carlos Eduardo | 2021-04-09

In the present work, a numerical model is developed to investigate the influence of wear and misalignment on the bearings of a stationary diesel engine. The model implemented considers the effects of surface wear on the bearing, cavitation effects, and surface roughness. For the numerical analysis, changes in the surface roughness of σ = 0.75 µm, σ = 1 µm, and σ = 1.25 µm are defined, and changes in the bearing load of 50%, 75%, and 100%. The results demonstrated that increasing the surface roughness intensifies the bearing wear, which represents 18% and 140% of the bearing clearance for the roughness of σ = 1 µm and σ = 1.25 µm, respectively. Additionally, the surface roughness causes a considerable increase in the bearing wear rate. The results described a maximum wear rate of 20 µm/s. In general, increasing the bearing load by 25% doubles the hydrodynamic pressure conditions increases friction force by 33%, and reduces lubrication film thickness by 12%. The analysis of the angle of deflection, φx and φy, shows that the moment and the degree of misalignment tend to increase significantly with the increase in the magnitude of the angle φy. Negative angles of deflection, φx, produce a greater increase in the degree of misalignment and the moment. This implies a greater chance of contact with the bearing surface. In conclusion, the proposed methodology serves as a reliable tool to simultaneously evaluate key parameters on the tribological behavior of bearings that further extend their endurance and minimize wear damage.

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El eslabón perdido de la innovación: Relación Universidad Empresa
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Sepúlveda Angarita, Magda Zarela | 2017

El artículo es una reflexión sobre la necesidad mutua de vinculación entre la universidad y la empresa (RUE). Esta articulación ha sido la ruta para alcanzar la innovación empresarial, la competitividad y el desarrollo regional. Sin embargo existe una disparidad de intereses que han dificultado el establecimiento de esta relación. El objetivo es analizar la (RUE) en Colombia. Para ello se recurrió a la metodología de un estudio documental, descriptivo aplicado. Se concluye que no existen fuertes nexos entre la academia y la empresa, situación presente en países emergentes con un tejido empresarial poco desarrollado y baja inversión en ACTI. Palabras Clave: universidad, empresa, innovación, competitividad

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El estado del desempeño científico en Colombia
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RAMIREZ ZAMBRANO, JORGE RAUL | 2018

El siguiente artículo tiene por objetivo analizar el estado del desempeño científico en Colombia durante el periodo 2006-2014. El referente teórico seguido es el propuesto por Salmi (2009), y, por Salmi & Altabach (2011). A nivel metodológico se usan indicadores secundarios del Observatorio de Ciencia, Tecnología de Colciencias para realizar un estudio comparativo que permita describir los avances y principales retos del país en materia de científica. Se evidencia que Colombia presenta brechas de inversión en ciencia, tecnología e innovación, este hallazgo es equivalente en productividad científica.

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Evaluation of Energy Losses in Auxiliary Systems and Mechanisms Subject to Friction in a Stationary Diesel Engine
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Pardo García, Carlos Eduardo | 2021

This research has developed a methodology to estimate energy losses associated with auxiliary systems and mechanisms subject to friction in a stationary diesel engine. The study methodology is based on mathematical models used to calculate engine friction forces and power losses. The analysis involves the cooling, the lubrication, the fuel injection system, and the engine's valve train, bearings, and piston mechanism. A stationary diesel engine with four load conditions and three rotational speed conditions has been taken as a reference for the study. The analysis of the results has showed that fuel injection is the auxiliary system with the highest energy consumption. In general, the cooling system, the lubrication, and the injection represent loss energy equivalent to 0.3%, 0.5%, and 0.9% of the chemical energy of the fuel. The interaction between the cylinder liner and the piston skirt is the main source of energy loss associated with friction processes. For valve train mechanisms, bearings and pistons it has been evidenced that these represent 1.25%, 1.91%, and 5.26% of the chemical energy of the fuel. In general, the methodology proposed in this research is a tool that allows diagnosing energy losses in auxiliary systems and engine mechanisms, which is useful for evaluating future strategies focused on energy improvement.

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Evaluation of Performance Parameters and Emissions of a Diesel Engine Fueled with Preheated Palm Oil Mill Effluent Biodiesel Blends
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Pardo García, Carlos Eduardo | 2021

The current research analyzes the effect of fuel preheating on performance parameters and emission characteristics in a stationary diesel engine fuelled with palm oil mill effluent biodiesel blends. The investigation has been carried out on an experimental test bench under four-engine load conditions. The fuel injection temperature range is set between 35-75 °C. From the results obtained, it has been possible to demonstrate that the preheating process allows the reduction of fuel consumption and an increase in the efficiency of the engine powered with POME 5 and POME 10 blends. The preheating process has the potential to reduce by 14 % BSFC and increase by 17% the BTE of the engine. Additionally, the results have showed a reduction potential of 17.2%, 16.5%, and 15.6% in CO2, HC, and smoke opacity emissions when preheating processes are used in POME biodiesel blends. In general, this type of strategy is a promising solution to incentivize the use of biodiesel blends from palm oil mill effluent.

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Evaluation of the fire resistance of steel-reinforced concretefilled steel tubular columns with a circular cross-section
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Rojas Suárez, J P | 2022-01-06

In the present investigation, an analysis of the fire resistance of the steel-reinforced concrete-filled steel tubular columns with circular cross-sections was carried out by means of numerical simulation. The development of the study was carried out by means of numerical simulation to predict the behavior of the column against fire. The results of the numerical model are validated by comparing the temperature levels obtained through experimental tests. From the results obtained, it is shown that the increase in the contact area between the steel and the concrete reduces the average temperature of the column, which implies a greater resistance to fire. The fire resistance of the columns with the steel profile designs are between 3.4 - 3.6 times higher compared to the column only made of concrete, which is an indication of the excellent performance of the steel-reinforced concrete-filled steel tubular columns with circular crosssections columns. In general, the methodology proposed in this research allows the analysis of the thermal physical phenomena of the different columns used for the construction of buildings.

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