Mostrando ítems 141-160 de 1541

Public space as a right: Accessibility for people with disabilities in the in the town centre of Cúcuta

Rangel Goyeneche, Diana Carolina; Corenel Ruiz, Luz Karime (2021-10-23)

Todo ciudadano sin importar su condición económica, social o física deberá gozar de las mismas condiciones, oportunidades de uso y disfrute del espacio público, libre de toda restricción o discrimina-ción que ...
Psychological well-being in nurses performing renal replacement therapy in times of COVID-19 pandemic

Martínez-Rojas, Sandra Milena; Ruiz-Roa, Silvia Liliana (2022-03-30)

Introducción: La pandemia por COVID-19 ha generado dete-rioro de la salud mental en los profesionales del sector salud, siendo desconocida su situación en las enfermeras al cuidado de pacientes con enfermedad renal crónica. ...
Education, innovation, entrepreneurship, growth and development in Latin America

Rincón Soto, Idana Beroska; Rengifo Lozano, Raúl Alberto; Hernández Suárez, César; Prada Núñez, Raúl (2022-07-01)

The importance of education to promote the processes inherent to innovation and entrepreneurship is currently of vital importance in professional training, which in turn links the impact it has on macroeconomic variables ...
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 ...
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 ...
Impact of plasticizers on the physical and structural properties of concrete used in constructions

GARZÓN AGUDELO, PEDRO; palacios alvarado, wlamyr; Medina Delgado, Byron (Reino Unido, 2021-06-04)

Concrete has an important presence in the construction of buildings and civil works, so its application requires taking into account the standards, technical specifications and technologies that guarantee the structural ...
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 ...
GIT-SEED: Strategy for collaborative work in software development courses

Adarme Jaimes, Marco Antonio; Rodriguez Tengo, Judith del Pilar; Gallardo Perez, Oscar Alberto (2022-07-18)

El desarrollo de software es considerado una actividad compleja debido a que intervienen un conjunto de personas especializadas en lenguajes y herramientas de programación que realizan tareas bien definidas dentro de ...
Relevance of the use of measurement units and orders of magnitude in the training of civil engineers

Márquez Peñaranda, J F; Cáceres Rubio, J R; Pineda Rodríguez, J R (Reino Unido, 2021-05-22)

Worldwide, a typical civil engineering program focuses in formal, natural, and applied sciences within an environment of ethical and social responsibility. Mathematics and computer sciences are the main formal sciences. ...
Characterization of clay material and rice husk from northeast Colombia

Sanchez Molina, Jorge; Bautista-Ruiz, Jorge; Sánchez Zúñiga, J. V. (Rasayan Journal of ChemistryIndia, 2021-01)

This research was to study materials from the region to use them industrially applying the circular economy concept. Clay Material and Rice Husk were evaluated in the manufacture of ceramic products. X-ray Diffraction and ...
Study of the benefit of solar energy through the management of photovoltaic systems in Colombia

Orjuela Abril, Martha Sofia ; PABON LEON, JHON ANTUNY; García, José Orlando (International Journal of Energy Economics and PolicyTurquía, 2021)

One of the biggest problems in energy management is the impact on the environment. For this, it is necessary to propose new techniques and strategies which reduce pollution. Examples such as carbon dioxide and other ...
Active learning and knowledge in physics: a reading from classroom work

Prada Nuñez, Raul; C A, Hernández Suarez; Gamboa, A A (Reino Unido, 2021-05-22)

This research article shows the findings of a study that sought to demonstrate the results of a methodological intervention implemented in classes of an eleventh-grade course in the area of Physics, in a public school ...
The rubric as an assessment tool for solving problem situations in the physics and mathematics teaching context

Salazar Torres, J; Rincón Leal, Olga Lucy; Vergel Ortega, Mawency (Reino Unido, 2021-05-22)

Polya propose the didactic problem-solving strategy to strengthen the teaching and learning processes in the mathematic field. Thus, this strategy can be applied in other fields such as physics teaching the article ...
Teaching physics through the implementation of a didactic strategy for the integration of knowledge in secondary school students

Prada Nuñez, Raul; Hernández, C A; Gamboa, A A (Reino Unido, 2021-05-21)

The objective was to evaluate the implementation of the knowledge integration model in high school students studying physics in a public educational institution in the city of San José de Cúcuta, Colombia. A quasi-experimental ...
Analysis of variables related to the mass flow of gaseous emissions in beehive ovens

mendoza lizcano, sonia maritza; Palacios Alvarado, W; Medina Delgado, Byron (Reino Unido, 2021-05-22)

In the combustion processes of the ceramic industry, large amounts of pollutant gas concentration are generated, so it is necessary to measure the system and the physical phenomenon, as well as the variables inherent to ...
Qos-based pattern recognition approach for web service discovery: Ar_wsds(Article)

Adarme Jaimes, Marco Antonio; Jimeno, Miguel (Suiza, 2021-08-31)

Web service composition requires high levels of integration and reliability of the services involved in its operation, which must meet specific quality criteria to ensure their proper execution and deployment. The discovery ...
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 ...
An application of physics: simply supported bridges made of post-tensioned concrete and structural steel beam

Márquez Peñaranda, J F; Pineda Rodríguez, J R; Rojas Suárez, J P (Journal of Physics: Conference SeriesReino Unido, 2022-01-06)

Bridges represent an important application of physics capable of solving real transportation problems. Knowledge of convenience of different mechanical solutions when analyzing and designing bridge is needed. For these ...
Smartphone and teamwork as a methodological tool for teaching and learning physics

Malndonado, E A; Ramírez, P; Avendaño Castro, William Rodrigo (Journal of Physics: Conference SeriesReino Unido, 2022-01-05)

This research is based on the usefulness of mobile phones as a tool for students to learn about uniform rectilinear motion in vertical free fall, based on experimental practice. To evaluate whether these mobile devices ...
Training action for physics teachers: an application of problem-based learning

Prada Núñez, Raul; C A, Hernández Suarez; Gamboa Suarez, A A (Journal of Physics: Conference SeriesReino Unido, 2022-01-05)

The teaching of problem-based learning is a didactic approach that requires a radical change in the role of the physics teacher because it is focused on learning, research, and reflection that students follow to reach a ...

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Public space as a right: Accessibility for people with disabilities in the in the town centre of Cúcuta
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Rangel Goyeneche, Diana Carolina | 2021-10-23

Todo ciudadano sin importar su condición económica, social o física deberá gozar de las mismas condiciones, oportunidades de uso y disfrute del espacio público, libre de toda restricción o discrimina-ción que tenga el propósito de obstaculizar su inclusión en el paisaje urbano. Por lo tanto, las personas con discapacidad, como actores dentro del mismo, deberán participar activamente en las decisiones que afecten su configuración, ordenamiento y proyección. A partir de la mirada personal de quienes se enfrentan desde su condición el espacio público en la zona céntrica de la ciudad colombiana de Cúcuta. El presente estudio desarrollado en el año 2018, consolida el análisis de percepción en materia de accesibilidad al medio urba-no de los individuos con los tipos de alteración más representativos en la ciudad. Para tal fin, la investigación hizo empleo de una me-todología cualitativa: muestreo avalancha y herramientas como la observación participante y entrevista, que permitieron consolidar una línea base de indicadores del espacio público para la población con limitaciones, como instrumento de medición de la calidad de vi-da y bienestar social en las ciudades y elemento enriquecedor en la formulación de las políticas públicas en materia de espacio público.

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Psychological well-being in nurses performing renal replacement therapy in times of COVID-19 pandemic
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Martínez-Rojas, Sandra Milena | 2022-03-30

Introducción: La pandemia por COVID-19 ha generado dete-rioro de la salud mental en los profesionales del sector salud, siendo desconocida su situación en las enfermeras al cuidado de pacientes con enfermedad renal crónica. Objetivo: Identificar el bienestar psicológico y sus diferencias de acuerdo a las variables demográficas y profesionales en en-fermeras que realizan hemodiálisis en tiempos de COVID-19. Material y Método: Estudio cuantitativo, descriptivo trans-versal, realizado en 52 enfermeras que realizan terapia de reemplazo renal en unidades de cuidado intensivo y de terapia renal en tiempos de COVID-19. Fueron obtenidas variables de tipo sociodemográfico, académico, laboral y se empleó la escala PGWBI para establecer los niveles de bienestar psicológico. Se utilizó el test de Mann-Whitney y Kruskall-Wallis realizando el post test de Dunn para compa-rar diferencias entre las variables estudiadas. Resultados: La edad promedio fue de 36,56±6,95 años. Los niveles de bienestar psicológico fueron positivos en todas las categorías de la escala, con excepción de la ansiedad y la depresión. De igual forma, se encontró que las variables género, estado civil, estabilidad, antigüedad laboral, remu-neración salarial y formación académica, muestran compor-tamiento diferenciado en las categorías que evalúa el ins-trumento. Conclusiones: Se identificaron altos niveles de bienestar psicológico en enfermeras que prestan cuidados en pacien-tes en terapia de reemplazo renal en tiempos de pandemia por COVID-19, donde factores como el estado civil, forma-ción post gradual y tener estabilidad laboral con mejores ingresos salariales, influencian positivamente las categorías que contribuyeron a los resultados de bienestar psicológico de las enfermeras evaluadas.

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Education, innovation, entrepreneurship, growth and development in Latin America
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Rincón Soto, Idana Beroska | 2022-07-01

The importance of education to promote the processes inherent to innovation and entrepreneurship is currently of vital importance in professional training, which in turn links the impact it has on macroeconomic variables such as economic growth and development of an economy. In this sense, the general objective of the research is to explain the influence of education on variables such as innovation, entrepreneurship and its impact on growth and development, in this particular, in Latin American countries. From the methodological point of view, a documentary review is made regarding future projections within the framework of these variables, and a statistical analysis of cases such as America, Europe and Asia, in order to integrate the different experiences and models, taking as reference the results that in praxis are currently consonant with each one in particular. Finally, the importance of framing in education the congruence and pragmatic coherence of the objectives of public policies in terms of innovation, research, science and technology is concluded, which in turn promotes the multiplier effect in synergy with the private business sector, promoting between both variables such as growth, poverty and development.

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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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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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Impact of plasticizers on the physical and structural properties of concrete used in constructions
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GARZÓN AGUDELO, PEDRO | 2021-06-04

Concrete has an important presence in the construction of buildings and civil works, so its application requires taking into account the standards, technical specifications and technologies that guarantee the structural stability expected by the manufacturers of materials and builders, and that is why the use of plasticizers arises as an adjuvant to the physical and mechanical properties of concrete. The objective of this article was to highlight the importance of plasticizers in the main properties of concrete used in construction and the ideal conditions for their use; based on a qualitative and quantitative approach methodology, scientifically validated sources of information related to the subject of the study were analyzed. It was possible to demonstrate significantly favorable results with the application of plasticizers as water reducers that increase mechanical strength, provided that they are used in an adequate proportion of these additives to improve the physical properties of concrete.

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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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GIT-SEED: Strategy for collaborative work in software development courses
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Adarme Jaimes, Marco Antonio | 2022-07-18

El desarrollo de software es considerado una actividad compleja debido a que intervienen un conjunto de personas especializadas en lenguajes y herramientas de programación que realizan tareas bien definidas dentro de la implementación del software. En este contexto de trabajo, se hace necesario que el estudiante en su inicio de formación como desarrollador de software, tome habilidades en buenas prácticas de desarrollo, una de los cuales comprende la utilización de sistemas de controles de versiones que permiten el registro y control de cambios de proyectos de software en repositorios específicos de código de programación donde interactúan varios usuarios. El propósito de este trabajo es presentar una estrategia de aprendizaje denominada GIT-SEED basada en casos donde el estudiante trabaje de forma colaborativa con el uso de un sistema de control de versiones bajo la plataforma GitLab, desde esta perspectiva se ofrece un mecanismo de apoyo para las habilidades de trabajo en equipo, análisis y pruebas de código de programación, despliegue de aplicaciones en entornos reales de trabajo y manejo de procesos de desarrollo de software ágiles. Los escenarios de prueba de la estrategia fueron aplicados a los estudiantes de estructura de datos y programación web del Programa de Ingeniería de Sistemas de la Universidad Francisco de Paula Santander, los resultados demuestran la gran afinidad y apropiación que tienen los estudiantes en el uso de estas herramientas y la facilidad de integración de sus aplicaciones con los componentes creados en su equipo de trabajo.

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Relevance of the use of measurement units and orders of magnitude in the training of civil engineers
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Márquez Peñaranda, J F | 2021-05-22

Worldwide, a typical civil engineering program focuses in formal, natural, and applied sciences within an environment of ethical and social responsibility. Mathematics and computer sciences are the main formal sciences. The most widely used natural sciences are physics, earth science, and chemistry. On the other hand, a student who begins the professional cycle of the program must develop skills in applied science to solve practical problems. Complex processes and concepts requiring skills related to mathematics and physics must be developed. Such processes and concepts demand an impeccable handling of operations which involve diverse precision degrees, measurement units and a high variety of basic and derived quantities. This work describes the identification and classification of the main errors made by students when solving written exams applied in a natural environment of structural design courses. Data were collected during four years at a university in Colombia. Report of errors was grouped into five categories named modelling, quantities, regulation, signs, and others. Collected errors were evaluated qualitatively and quantitatively. In addition, each error was assigned to a risk level (high, intermediate, low) according to its potentiality to generate catastrophic errors in professional practice. The quality and number of observed errors seem to be correlated with the time of year in which they occur. On the other hand, the high-risk errors resulted to outweigh the two lower risk levels. This finding is worrying and serves as the basis for making an urgent call to review the way of teaching and its relationship with practical results. In synthesis, this study presents a novel manner to study the formation errors in engineering civil programs. In the near future, it is expected to use the results of this research to propose a procedure for the design and feedback of teaching strategies consistent with the evaluation objectives of each course.

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Characterization of clay material and rice husk from northeast Colombia
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Sanchez Molina, Jorge | 2021-01

This research was to study materials from the region to use them industrially applying the circular economy concept. Clay Material and Rice Husk were evaluated in the manufacture of ceramic products. X-ray Diffraction and X-ray Fluorescence techniques were used to determine the raw materials' chemical and mineralogical composition. Thermal analysis techniques (TG and DTG) were used to complement the study. The XRD results showed an abundance of quartz. The results of the thermal analysis establish significant losses due to calcination. The thermal conductivity was also measured in ceramic specimens made from two types of pastes, one with 100% Clay Material and the other with a 5% substitution for Rice Husk. The results showed a decrease in thermal conductivity in the test tubes with the addition of Rice Husk. Consequently, the Rice Husk as a substitute for the Clay Material allows for ceramic production with thermal efficiency.

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Study of the benefit of solar energy through the management of photovoltaic systems in Colombia
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Orjuela Abril, Martha Sofia | 2021

One of the biggest problems in energy management is the impact on the environment. For this, it is necessary to propose new techniques and strategies which reduce pollution. Examples such as carbon dioxide and other greenhouse gas emissions promote an increase in the carbon footprint. This carries the search for resources from renewable sources as sunlight, wind, rain, waves, etc. From these sources, solar energy could be used in Colombia, especially the Atlantic Coast, due to high solar radiation in this region. This study is going to collect information about the advantages and disadvantages of using photovoltaic systems (PV systems) for solar energy management with a good cost-efficiency ratio. On the other hand, the development of solar energy will be studied and compared with other energy sources. In Colombia, there is a set of energy and regulatory policies around small self-generators with renewable energy sources, which can be natural or legal persons, that is, self-generators could be civilians, merchants, or small industries. Finally, it will be discussed about the energy plans as a proposal for improved energy management in the future.

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Active learning and knowledge in physics: a reading from classroom work
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Prada Nuñez, Raul | 2021-05-22

This research article shows the findings of a study that sought to demonstrate the results of a methodological intervention implemented in classes of an eleventh-grade course in the area of Physics, in a public school in the city of San José de Cúcuta, Colombia. The intervention consisted of applying some active learning strategies accompanied by methodological tools such as collaborative work in order to measure the impact of the intervention on the level of disciplinary knowledge of students with a pre-test and post-test. The results show a significant increase with a value of 0.49 at the end of the intervention, which suggests that the subjects participating in the study improved their level of conceptual appropriation in physics after the application of active learning strategies.

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The rubric as an assessment tool for solving problem situations in the physics and mathematics teaching context
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Salazar Torres, J | 2021-05-22

Polya propose the didactic problem-solving strategy to strengthen the teaching and learning processes in the mathematic field. Thus, this strategy can be applied in other fields such as physics teaching the article proposes an evaluation strategy based on the design of a rubric to assess the processes associated with solving mathematical problems, as a classroom research work based on Research, Pedagogical Action. As one of the results, an analytical rubric composed of criteria and indicators associated with the steps of Polya problem solving is proposed, as well as a reflection associated with the teaching of problem solving in the engineering area.

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Teaching physics through the implementation of a didactic strategy for the integration of knowledge in secondary school students
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Prada Nuñez, Raul | 2021-05-21

The objective was to evaluate the implementation of the knowledge integration model in high school students studying physics in a public educational institution in the city of San José de Cúcuta, Colombia. A quasi-experimental model was applied. An intervention was implemented as a didactic strategy for the integration of knowledge based on the Pragmatic Pedagogical Principles, its operative criteria, and activities. Conceptual progress is reported by means of Hake's normalized factor or gain, which was modified to the rating scales, and the results of partial exams are considered, implementing a continuous and formative evaluation system. The results were compared between the experimental and control groups. It was found that the experimental group showed better academic achievement and performance than the control group. This suggests that the results generated a continuous learning progress thanks to the application of the operative judgments of the corresponding principles.

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Analysis of variables related to the mass flow of gaseous emissions in beehive ovens
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mendoza lizcano, sonia maritza | 2021-05-22

In the combustion processes of the ceramic industry, large amounts of pollutant gas concentration are generated, so it is necessary to measure the system and the physical phenomenon, as well as the variables inherent to the process, for subsequent estimation in terms of physical magnitudes, and a dimensional analysis, this allows to generate approximations in the causal relationships of the variables. The objective of the research is to analyze the behavior of the variables involved in the process and the influence of the mass flows of polluting gases. An exploratory and experimental methodology was used, for this, the data were taken with the technique of direct measurement in the sources of gas emissions and subsequently subjected to simulation in software such as AMOS V24.0 and LISREL V8.8., on the other hand, the data were subjected to an exploratory and confirmatory factorial analysis, using SPSS software version 24.0. As a result, the variables capacity and production are practically identical, which leads to a high correlation and, consequently, an undesired multicollinearity between the variables, so the suggestion is to omit one of them. On the other hand, the sulfur percentage variable is inversely correlated with most of the variables and its saturation is not clear, so it is theoretically sustained as a latent variable of the SO2 indicator.

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Qos-based pattern recognition approach for web service discovery: Ar_wsds(Article)
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Adarme Jaimes, Marco Antonio | 2021-08-31

Web service composition requires high levels of integration and reliability of the services involved in its operation, which must meet specific quality criteria to ensure their proper execution and deployment. The discovery and selection of web services currently face optimization problems. Many services might satisfy a requirement with similar quality criteria. Because of this, software developers have to choose the most appropriate services for a given composition, complicated by the rapid increase in providers and services available in the cloud. Service composition also implies coupling according to a composition flow and non-functional requirement criteria. Such requirements make selection and composition a complex task not previously solved in the literature. This paper presents Ar_WSDS, a computational approach for web services discovery and selection in cloud environments, which bases its implementation on the brain’s pattern recognition systematic functioning. This process allows classifying web services through recognition modules created dynamically based on their quality parameters, resulting in a set of web services suitable for a web service composition. This approach allows a solution to the selection problem using less complex tasks. This paper introduces an architectural and procedural definition that provides the web service description with a pattern to recognize and select services using different recognition levels. We simulated our approach and evaluated it using a dataset from the QWS project that offers a set of quality criteria collected from different providers. The web services are recognized and classified using different quality criteria for the composition and each of their services. The results demonstrate the effectiveness of the discovery and selection process compared to other approaches. Furthermore, Ar_WSDS allows us to recognize and filter out web services with ambiguity and similarity in their provider information, a process that minimizes the discovery space for services.

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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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An application of physics: simply supported bridges made of post-tensioned concrete and structural steel beam
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Márquez Peñaranda, J F | 2022-01-06

Bridges represent an important application of physics capable of solving real transportation problems. Knowledge of convenience of different mechanical solutions when analyzing and designing bridge is needed. For these reasons, this work is focused on the study of convenience of using two types of bridges. Simply supported short-medium span bridges (30 m to 45 m) are usually excessively long when choosing reinforced concrete solutions and usually short for other types of structures such as cable-stayed or cantilever bridges. The suitability of simply supported bridges leads to the need of studying their cost benefit ratios. This work studies the cost benefit ratio for post-tensioned concrete beams and structural steel girders in simply supported straight bridges. Eight models built of type I sections were used in both cases to analyze the bridges using a software based on the stiffness method. Span of each bridge was set to 30 m, 35 m, 40 m, and 45 m. The convenience of each type of bridge was done comparing the total and the cost per linear meter of each solution (post-tensioned and structural steel). Comparison was done using material consumption, labor, and construction processes costs only. Also, allowable vertical displacement given by current bridge design standards was verified

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Smartphone and teamwork as a methodological tool for teaching and learning physics
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Malndonado, E A | 2022-01-05

This research is based on the usefulness of mobile phones as a tool for students to learn about uniform rectilinear motion in vertical free fall, based on experimental practice. To evaluate whether these mobile devices allow better learning on the subject, a pre-test/post-test design was carried out with 43 students participating in the 9th grade in natural sciences. McNemar and Stuart-Maxwell non-parametric tests were applied. The proposal on the experimental practice gave satisfactory results when comparing the pre-test and post-test, in the analysis of the particular and global form of the answers.

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Training action for physics teachers: an application of problem-based learning
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Prada Núñez, Raul | 2022-01-05

The teaching of problem-based learning is a didactic approach that requires a radical change in the role of the physics teacher because it is focused on learning, research, and reflection that students follow to reach a solution to a problem situation as a starting point for the acquisition and integration of knowledge in science. The results of a training action for physics teachers on the implementation, their perceptions, and perspectives on the feasibility of the problem-based Learning approach are presented. The study is quasi-experimental in nature with pre-test and post-test in the study variables. The results suggest that the teachers' perceptions are positive, which is why they consider that its implementation in teaching is viable, however, they need more elements that facilitate their execution in the classroom, such as understanding the theoretical foundations and their pedagogical use successful in the classroom. It is concluded that, for the physics teaching process, problem-based learning is an innovation because it allows the student to learn actively, in which inquiry is relevant for the development of skills and appropriation of knowledge, which in the framework of natural sciences leads to the reconstruction of the scientific method.

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