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Papers by JUAN CARLOS ROJAS GARNICA

Research paper thumbnail of Preliminary development of a system to manipulate and monitoring a flexible manufacturing cell

Revista de Operaciones Tecnologicas, 2021

Flexible Manufacturing Systems (FMS) are more commonly used in modern industry due to the benefit... more Flexible Manufacturing Systems (FMS) are more commonly used in modern industry due to the benefits offered, such as: low-cost production, easy adaptation to elaborate different products according to the client necessities. A Flexible Manufacturing Cell (FMC) has two or three workstations; moreover, a system to control and manipulate de process. Industrial communications protocols are used to communicate workstations of a FMC, such as: Profibus, Ethernet, Device Net, etc. For the case of not have such protocol to communicate devices, due to an incompatibility between protocols, an alternative solution has been implemented in order to perform the same function. In this work, is presented the obtained results of a preliminary development of a system capable to manipulate and monitoring a flexible manufacturing cell using a communication card using a microcontroller to communicate a HAAS VF2 machining center and a FANUC robot M6iB. Moreover, an user interface is developed using LabVIEW ...

Research paper thumbnail of Design of an equipment for polishing of medical vagin dilators in order to eliminate edges and burrs

Research paper thumbnail of Análisis de la generación de las irreversibilidades a partir del Coeficiente de Operación en un sistema de refrigeración por compresión mecánica de vapor con R-134a

Revista de Ingeniería Mecánica, Dec 31, 2019

Research paper thumbnail of Replicación de Características Superficiales por medio de la Teoría Fractal

Ingenieria, 2013

RESUMEN En este trabajo se presenta un método para la replicación gráfica de características supe... more RESUMEN En este trabajo se presenta un método para la replicación gráfica de características superficiales de elementos mecánicos mediante el uso de la teoría fractal. Se parte de la obtención del espectro de densidad superficial, el cual se obtiene mediante la medición de la variación de alturas en diferentes zonas de la superficie muestra. A partir de este último se obtienen las amplitudes que se aplican en la función periódica exponencial que replica la superficie. Este método puede aplicarse al número de escalas que se requiera para la definición completa de componentes de ondulaciones y rugosidades de la superficie. Los resultados obtenidos confirman que el método es una alternativa sencilla de replicación sin importar el tamaño y número de escalas en la superficie. Sin embargo, tiene como limitantes a la resolución de las mediciones superficiales y al cumplimiento de la auto-similitud fractal.

Research paper thumbnail of Diseño e implementación de una Interfaz de Control para la Integración de una Celda de Manufactura Flexible

Revista del Diseño Innovativo, Dec 31, 2019

Research paper thumbnail of Diseño e implementación de un sistema de medición de respuesta de sensores de gas

Revista de aplicaciones de la ingeniería, Sep 30, 2019

Research paper thumbnail of Paradigmas del proceso enseñanza-aprendizaje a distancia

Online teaching and learning are an alternative paradigm to face-to-face education. It promotes t... more Online teaching and learning are an alternative paradigm to face-to-face education. It promotes the generation of knowledge through theoretical and methodological processes derived from the development of science and technology in the field of communication and information. With distance education, the teacher undertakes innovative strategies that promote meaningful learning. In this paradigm, the teacher as an educational subject is not excluded, on the contrary, it assumes a new role that transits towards the new culture of distance education based on the diversity of resources that the Web has. The most relevant challenges of this new paradigm are accessibility, personalized system, flexibility in study, and interactivity with better learning materials and resources.

Research paper thumbnail of Análisis de las irreversibilidades en un proceso de paro y arranque en un sistema de refrigeración con R-134a

In this work, an evaluation of the energy in a start-stop process is made by analyzing the genera... more In this work, an evaluation of the energy in a start-stop process is made by analyzing the generated irreversibilities in a refrigeration system by mechanical vapor compression with R-134a refrigerant at a flow of 1.0 L / s. This system is installed in the LABINTHAP of the SEPI-ESIME-IPN. For this analysis, there is software that captures data on the pressures and temperatures from the refrigerant at the inlet and outlet of the evaporator, compressor, condenser, and expansion valve at oneminute intervals. For the analysis of the generated irreversibilities, the first and second laws of thermodynamics were used. And, in the process evaluation of stopping and starting, it was shown that the compressor sets a trend of higher energy consumption, so a process of regulation of the refrigeration system by mechanical compression of steam is proposed.

Research paper thumbnail of Failure by deformation in the lateral contact between sinusoidal asperities

Advances in Mechanical Engineering, May 1, 2016

This article presents a study about the lateral force which produces the failure by deformation b... more This article presents a study about the lateral force which produces the failure by deformation between asperities with the sine profile. This study begins with obtaining this force with experimental tests and numerical simulations by the finite element method, which shows good correspondence. The formulation of an analytical procedure to calculate the lateral force is also presented. This formulation is based on the theory of Hertz, which considers lateral contact between asperities, which causes deformation and eventually the failure. The results obtained by this method are compared to the results from tests and simulations using materials with different values of elasto-plasticity. The analysis of results shows the differences between analytical formulation and experimental data, according to which an empirical equation is formulated, whose results improve the approximation to the experimental data. The simplicity of the empirical equation formulated and adequate representation by the results of this, in tests and simulations, make it a numerical model useful for studies of surface wear.

Research paper thumbnail of Device and method of holding an enclosure

Research paper thumbnail of Teaching thermodynamics in Engineering based on competences

ECORFAN Journal Spain

This paper shows an analysis of the activities carried out in the classroom on topics which invol... more This paper shows an analysis of the activities carried out in the classroom on topics which involve thermodynamics. This proposal contemplates methodological aspects and competences of the subject on basic topics that involve the understanding of the phenomena involving the first and second laws of thermodynamics. The proposal aims for the student to develop a cognitive process which can be used as a tool to help improve their learning. This process is characterized by a feedback between the implementation of the changes concerning the teaching-learning process and the evaluation process of the achieved learning. The analysis of the evaluation is based on the phenomena that involve fundamental concepts such as energy, work and heat, as well as the need to develop assessment instruments according to the competence that the student needs to develop. The results show a significant progress, in terms of the level of learning achieved, by making an annual comparison of school performance...

Research paper thumbnail of Cálculo de la generación de entropía a partir del Proceso de Temperatura Promedio en un sistema de refrigeración por compresión mecánica de vapor con R-134a

Revista de Operaciones Tecnologicas

The Average Temperature Process (PAT) is modeled by an equation that is used to calculate the inc... more The Average Temperature Process (PAT) is modeled by an equation that is used to calculate the increase in energy needed for the refrigeration cycle, which is equivalent to the energy degradation that corresponds to the production of entropy. This work shows experimentally that the increase in entropy, taking into account the processes of heat transfer that occur in the condensation temperature and in the evaporation temperature between the mechanical vapor compression refrigeration system and the environment, is directly related to the falls of pressure presented in the suction pipe and in the compression process, as well as the heat losses that exist between the main components (evaporator, compressor, condenser and expansion throttling) and the environment. From this development, the behavior of the refrigeration cycle is evaluated in order to obtain a minimum entropy generation criterion in the main components. Analytical as well as experimental results are shown using R-134a ref...

Research paper thumbnail of El impacto de las redes sociales en el proceso de enseñanza aprendizaje de la termodinámica

Revista de Tecnologías de la Información

The development and use of social networks in the teaching-learning process that students develop... more The development and use of social networks in the teaching-learning process that students develop, makes it an important and almost essential tool in the educational process. This entails changes, of various absolutely inevitable characteristics when it comes to launching innovative proposals in the teaching of thermodynamics. Hence the training processes in universities demand new models of pedagogical strategy capable of responding to the needs of the new society. However, in practice, during the teaching process of thermodynamics, it has been detected that traditionalist teaching approaches are still assumed, which does not meet the expectations demanded by the new training models. The research carried out is aimed at studying the evaluation of the teaching-learning process in its formative and meaningful training, with the objective of promoting formative evaluation through the use of virtual training environments.

Research paper thumbnail of Preliminary development of a system to manipulate and monitoring a flexible manufacturing cell

Revista de Operaciones Tecnologicas, 2021

Flexible Manufacturing Systems (FMS) are more commonly used in modern industry due to the benefit... more Flexible Manufacturing Systems (FMS) are more commonly used in modern industry due to the benefits offered, such as: low-cost production, easy adaptation to elaborate different products according to the client necessities. A Flexible Manufacturing Cell (FMC) has two or three workstations; moreover, a system to control and manipulate de process. Industrial communications protocols are used to communicate workstations of a FMC, such as: Profibus, Ethernet, Device Net, etc. For the case of not have such protocol to communicate devices, due to an incompatibility between protocols, an alternative solution has been implemented in order to perform the same function. In this work, is presented the obtained results of a preliminary development of a system capable to manipulate and monitoring a flexible manufacturing cell using a communication card using a microcontroller to communicate a HAAS VF2 machining center and a FANUC robot M6iB. Moreover, an user interface is developed using LabVIEW ...

Research paper thumbnail of Design of an equipment for polishing of medical vagin dilators in order to eliminate edges and burrs

Research paper thumbnail of Análisis de la generación de las irreversibilidades a partir del Coeficiente de Operación en un sistema de refrigeración por compresión mecánica de vapor con R-134a

Revista de Ingeniería Mecánica, Dec 31, 2019

Research paper thumbnail of Replicación de Características Superficiales por medio de la Teoría Fractal

Ingenieria, 2013

RESUMEN En este trabajo se presenta un método para la replicación gráfica de características supe... more RESUMEN En este trabajo se presenta un método para la replicación gráfica de características superficiales de elementos mecánicos mediante el uso de la teoría fractal. Se parte de la obtención del espectro de densidad superficial, el cual se obtiene mediante la medición de la variación de alturas en diferentes zonas de la superficie muestra. A partir de este último se obtienen las amplitudes que se aplican en la función periódica exponencial que replica la superficie. Este método puede aplicarse al número de escalas que se requiera para la definición completa de componentes de ondulaciones y rugosidades de la superficie. Los resultados obtenidos confirman que el método es una alternativa sencilla de replicación sin importar el tamaño y número de escalas en la superficie. Sin embargo, tiene como limitantes a la resolución de las mediciones superficiales y al cumplimiento de la auto-similitud fractal.

Research paper thumbnail of Diseño e implementación de una Interfaz de Control para la Integración de una Celda de Manufactura Flexible

Revista del Diseño Innovativo, Dec 31, 2019

Research paper thumbnail of Diseño e implementación de un sistema de medición de respuesta de sensores de gas

Revista de aplicaciones de la ingeniería, Sep 30, 2019

Research paper thumbnail of Paradigmas del proceso enseñanza-aprendizaje a distancia

Online teaching and learning are an alternative paradigm to face-to-face education. It promotes t... more Online teaching and learning are an alternative paradigm to face-to-face education. It promotes the generation of knowledge through theoretical and methodological processes derived from the development of science and technology in the field of communication and information. With distance education, the teacher undertakes innovative strategies that promote meaningful learning. In this paradigm, the teacher as an educational subject is not excluded, on the contrary, it assumes a new role that transits towards the new culture of distance education based on the diversity of resources that the Web has. The most relevant challenges of this new paradigm are accessibility, personalized system, flexibility in study, and interactivity with better learning materials and resources.

Research paper thumbnail of Análisis de las irreversibilidades en un proceso de paro y arranque en un sistema de refrigeración con R-134a

In this work, an evaluation of the energy in a start-stop process is made by analyzing the genera... more In this work, an evaluation of the energy in a start-stop process is made by analyzing the generated irreversibilities in a refrigeration system by mechanical vapor compression with R-134a refrigerant at a flow of 1.0 L / s. This system is installed in the LABINTHAP of the SEPI-ESIME-IPN. For this analysis, there is software that captures data on the pressures and temperatures from the refrigerant at the inlet and outlet of the evaporator, compressor, condenser, and expansion valve at oneminute intervals. For the analysis of the generated irreversibilities, the first and second laws of thermodynamics were used. And, in the process evaluation of stopping and starting, it was shown that the compressor sets a trend of higher energy consumption, so a process of regulation of the refrigeration system by mechanical compression of steam is proposed.

Research paper thumbnail of Failure by deformation in the lateral contact between sinusoidal asperities

Advances in Mechanical Engineering, May 1, 2016

This article presents a study about the lateral force which produces the failure by deformation b... more This article presents a study about the lateral force which produces the failure by deformation between asperities with the sine profile. This study begins with obtaining this force with experimental tests and numerical simulations by the finite element method, which shows good correspondence. The formulation of an analytical procedure to calculate the lateral force is also presented. This formulation is based on the theory of Hertz, which considers lateral contact between asperities, which causes deformation and eventually the failure. The results obtained by this method are compared to the results from tests and simulations using materials with different values of elasto-plasticity. The analysis of results shows the differences between analytical formulation and experimental data, according to which an empirical equation is formulated, whose results improve the approximation to the experimental data. The simplicity of the empirical equation formulated and adequate representation by the results of this, in tests and simulations, make it a numerical model useful for studies of surface wear.

Research paper thumbnail of Device and method of holding an enclosure

Research paper thumbnail of Teaching thermodynamics in Engineering based on competences

ECORFAN Journal Spain

This paper shows an analysis of the activities carried out in the classroom on topics which invol... more This paper shows an analysis of the activities carried out in the classroom on topics which involve thermodynamics. This proposal contemplates methodological aspects and competences of the subject on basic topics that involve the understanding of the phenomena involving the first and second laws of thermodynamics. The proposal aims for the student to develop a cognitive process which can be used as a tool to help improve their learning. This process is characterized by a feedback between the implementation of the changes concerning the teaching-learning process and the evaluation process of the achieved learning. The analysis of the evaluation is based on the phenomena that involve fundamental concepts such as energy, work and heat, as well as the need to develop assessment instruments according to the competence that the student needs to develop. The results show a significant progress, in terms of the level of learning achieved, by making an annual comparison of school performance...

Research paper thumbnail of Cálculo de la generación de entropía a partir del Proceso de Temperatura Promedio en un sistema de refrigeración por compresión mecánica de vapor con R-134a

Revista de Operaciones Tecnologicas

The Average Temperature Process (PAT) is modeled by an equation that is used to calculate the inc... more The Average Temperature Process (PAT) is modeled by an equation that is used to calculate the increase in energy needed for the refrigeration cycle, which is equivalent to the energy degradation that corresponds to the production of entropy. This work shows experimentally that the increase in entropy, taking into account the processes of heat transfer that occur in the condensation temperature and in the evaporation temperature between the mechanical vapor compression refrigeration system and the environment, is directly related to the falls of pressure presented in the suction pipe and in the compression process, as well as the heat losses that exist between the main components (evaporator, compressor, condenser and expansion throttling) and the environment. From this development, the behavior of the refrigeration cycle is evaluated in order to obtain a minimum entropy generation criterion in the main components. Analytical as well as experimental results are shown using R-134a ref...

Research paper thumbnail of El impacto de las redes sociales en el proceso de enseñanza aprendizaje de la termodinámica

Revista de Tecnologías de la Información

The development and use of social networks in the teaching-learning process that students develop... more The development and use of social networks in the teaching-learning process that students develop, makes it an important and almost essential tool in the educational process. This entails changes, of various absolutely inevitable characteristics when it comes to launching innovative proposals in the teaching of thermodynamics. Hence the training processes in universities demand new models of pedagogical strategy capable of responding to the needs of the new society. However, in practice, during the teaching process of thermodynamics, it has been detected that traditionalist teaching approaches are still assumed, which does not meet the expectations demanded by the new training models. The research carried out is aimed at studying the evaluation of the teaching-learning process in its formative and meaningful training, with the objective of promoting formative evaluation through the use of virtual training environments.