Facultad de Ciencias Químicas

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Actitudes hacia la química en estudiantes universitarios conforme avanzan en la carrera
(Universidad de Cuenca, 2015-04-01) Silvina Reyes, María; Porro, Silvia; Pirovani, María Elida
The aim of this work was to estimate the change of the student attitudes towards chemistry on biology careers (“Profesorado en Biología and Licenciatura en Biodiversidad”) at Universidad Nacional del Litoral, Santa Fe, Argentina. The student attitudes were studied during three stages: at the beginning (1st year), during (3rd year) and at the end (5th year) of their careers. The instrument chose to assess the attitudes of the students was a questionnaire according to Likert scale. All the students who attended each of the analyzed years (45, 30 and 20 students respectively) were surveyed. The obtained results indicate statistically significant differences (p ≤ 0.05) between attitudes towards chemistry presented by students of 3rd and 5th with respect to 1st year. This research showed that there is a positive trend in attitudes toward chemistry as students progress through university education. It could be inferred that it is possible to improve the attitude of the early college years, whether methodologies of teaching and evaluation, both in the last years of high school, and in the first years of college, are reviewed, to improve the attitude towards the chemistry of the students of biological careers from the beginning.
Algoritmo genético para sintonización de pid basado en la integral del error absoluto
(Universidad de Cuenca, 2018-05) Pillajo, Carlos; Bonilla, Paul; Hincapié, Roberto
Despite the rapid development in systems of process control, the PID controller (Proportional-Integral-Derivative) is the most widely used in the industry, because its simple and robust features are enough to work in a variety of processes. However, it is properly tuned complex gains PID, because the processes are nonlinear systems, or stationary, so that its characteristics change over time. The tuning process is not trivial, since it largely depends on the process to be controlled, and there is no method that is appropriate for all applications. Given this adaptive control systems, where the controller performs a self-tuning arise. Are designed very sophisticated about classical PID strategies, these techniques have artificial intelligence. In this paper a genetic algorithm capable of tuning PID controllers based on the criterion of the integral absolute error (IAE), the algorithm is simulated and compared with matlab tools designed for this purpose..
Alimentación fuera del hogar, consumo y preferencias de la población de Cuenca sobre la restauración comercial
(Universidad de Cuenca, 2017) Tosi Vélez, Augusto; Serrano López, Ana Lucía
The objective of this research is to determine the consumption preferences of the population outside the household in Cuenca city and the factors of influence. For which, a sample of 1,000 individuals randomly selected in the Historical Center of the city of Cuenca was selected, all of them older than 16 years of age, with a similar percentage between men and women. A survey was applied, including Eighteen closed questions and two open questions. The results were processed according to sex and age groups. For the analysis, statistics test were applied such as Student t, Anova or Chi square, depending on the attributes of the variables. In conclusion, it has been determined that there is a high level of preference for consumption outside home during the weekends, being the quality of the product and the restaurant the most influential consumption factors intrinsically with consumer factors being more influential the quality of the product and the restaurant.
Análisis de ciclos fusión-solidificación de ceras de parafina
(Universidad de Cuenca, 2015-09) Reyes, Alejandro; Vásquez, José; Sepúlveda, Francisco
The global energy shortage has prompted for research of accumulate renewable energy alternatives, i.e., solar energy. Paraffin wax has a Phase Change Material (PCM) which allows to accumulate energy. Depending on their physical composition the melting temperature could be between 40° and 65° C, respectively. However, there is lack of information regarding the wax´s material chractersitcis after high number of cycles. Therefore, in the present work, a paraffin wax fusion/solidification system was designed and it further implemented. It was also used a data recording system to analyze melting, solidification cycles, and temperature profiles in the time domain. . The wax was heated and cooled in a Peltier cell. Two types of wax were analyzed for about 1000 cycles. It was analyzed periods and amplitudes of each cycle. The time cycle for PT 58 and PT Ch wax were 340 and 160 seconds, respectively. Finally, the results showed that the temperature profiles have no significant differentes, this means that the waxes do not undergo chemical or structural changes.
Análisis de dos métodos de medición equidad de género, aplicados en Latinoamérica; beneficios que obtienen las organizaciones y empresas
(Universidad de Cuenca, 2017) Ramírez, Fernanda Y.
This is a review of the two methodologies applied in Latin America, that can be beneficial in the organizations and companies that measure gender equity, and could be applied in or context This document also analyzed the legal framework and public policies, to gender equality in the organizations is no longer merely declaratory and becomes effective in bridging the gap between men and women. In addition, it addresses gender equity since education, it is known that women and men has equal terms to prepared, however, there is no equity in laboral participation and same conditions. Finally, show the benefits in terms of productivity, which has the implementation of measures and plans of gender equity for companies and organizations by improving the work climate and the publicity of companies with gender equity.
Análisis de la composición corporal en estudiantes de la Carrera de Cultura Física de la Universidad de Cuenca 2015
(Universidad de Cuenca, 2016-05) Brito, Vicente; Contreras, Teodoro; Barreto, Jorge
The purpose of this study was to define the anthropometric profile and parameters related to body composition of a group of university students. The methodology / standards proposed by Carter and Faulkner and approved by the International Society for the Advancement of the kineanthropometry (ISAK) were performed as basic anthropometric examination. In total 12 anthropometric variables were considered weight, height, 5-fold (subscapularis, triceps, abdominal, suprailiac, medial leg), 3 diameters (radial biestiloideo, biepicondylar of the humerus and femur biepicondylar) and 2 perimeters (contracted medial arm and leg). The results for males were: Age 23.05 ±4.07 years; Weight 72.88 ±7.20 kg; Size 168.02 ±6.67 cm, and with an Ideal Weight of 63.22 ±7.41 kg; and the results for women were: Age 23.82 ±3.17 years; Weight 57.95 ±8.61 kg; and Size 158.09 ±7.51 cm, Ideal Weight of 54.30 ±7.59. It can be concluded that the somatotype predominant among males was the endo-mesomorphic with median values of Endomorphic =3.16, mesomorphic= 5.03 and for ectomorphic =2.17, while among women the meso endomorphic was the predominan type with values of 5.04 for endomorphic, 4.50 for mesomorphic and 1.51 for ectomorphic.
Análisis de la estática para la síntesis de furfural por destilación reactiva
(Universidad de Cuenca, 2015-12) Aristizábal M., Valentina; Parra R., Daniela; Pisarenko, Yuri A.; Cardona A., Carlos Ariel
Nowadays, there is a big attention paid on furan derivatives and catalytic processes, mainly to convert the sugars contained in lignocellulosic biomass. In this sense, the furfural also receives special attention as potential chemical building blocks for the production of bio products and biofuels. Due to the difficulties presented in the separation of furfural in the conventional process, this paper presents the separation analysis to obtain furfural of high purity from xylose dehydrated by reactive distillation as unconventional process. The basic theory of static analysis is used to acquire the best information of the reactive distillation process. This allows obtaining a technological scheme that achieves a mole fraction of about 0.9 furfural.
Análisis de las simulaciones del proceso de deshidratación del gas natural con Aspen Hysys y Aspen Plus
(Universidad de Cuenca, 2015-09) Benitez, Leonel Alberto; Gutiérrez, Juan Pablo; Ale Ruiz, Liliana; Erdmann, Eleonora; Tarifa, Enrique
Natural gas has taken an important strategic role in world energy supply as a result of the growing global energy demand. Water is probably the most undesirable component found in raw natural gas because its presence can produce hydrate formation, and it can also lead to corrosion or erosion problems. Due to these often expensive consequences natural gas should be subjected to conditioning processes in order to achieve strict specifications for sales, transportation and final uses. In recent years, process simulation is playing an important role in the oil and gas industry as an appropriate and powerful tool for the design, characterization, optimization, and monitoring of industrial processes performance. In this paper the development of two steady state simulations of natural gas dehydration by absorption with triethylene glycol (TEG) is described, using commercial process simulators such as Aspen HYSYS V8.3 and Aspen PLUS V8.2. Natural gas composition, plant configuration and operating conditions adopted for designs and simulation are those generally used in the area in conditioning plants of natural gas in the province of Salta (Argentina).
Análisis del proceso de extracción de antioxidantes del hueso de oliva
(Universidad de Cuenca, 2015-12) Hernández, Valentina; Idárraga, Angela M.; Cerón, Ivonne X.; Romero-García, Juan M.; Castro, Eulogio; Dávila, Javier A.; Cardona, Carlos A.
Olive tree cultivation is spreading worldwide due to the beneficial effects of olive oil consumption. Olive oil production process and table olive industries are the major sources of olive stones. Currently, this by-product is used in direct combustion to produce energy as electricity or heat. However, there are other possibilities for taking full advantage of this renewable source, and its recovery would represent an economic improvement for farmers. The olive stone not only contains primarily lignocellulosic, but also it has revealed the presence of phenolic compounds with antifungal and antibacterial properties. For this reason, in this work the extraction of antioxidant compounds is proposed as a process with supercritical fluids for olive stone. These bioactive molecules can be used in the food industry, cosmetics, functional foods, and nutraceuticals additives. During the analysis of percent inhibition of DPPH method, an antioxidant capacity of 5.63 mg trolox equivalent (TE) per g dry matter was found.
Análisis tecno-económico de una biorefinería a partir de residuos del plátano
(Universidad de Cuenca, 2015-12) Sánchez Rendón, Julio César; Daza Serna, Laura Vanessa; Hernández Piedrahita, Valentina; Castro Galiano, Eulogio; Cardona Alzate, Carlos Ariel
Banana pseudostem is a lignocellulosic material highly available in Colombia due to the large demand of plantain bunches. This material is incorrectly wasted and disposed causing both soil and water source contamination. The present work describes the simulation and techno-economic evaluation of furfural, ethanol, xylitol and acetic acid production under biorefinery concept, by using banana pseudostem as raw material in two process stages: base case in which only previous chemicals production is made, and another where besides raw material remainder solid fraction is used for energy cogeneration through gasification system. The cost obtained and gain margin analysis show furfural, xylitol and lactic acid production viability from banana pseudostem; and energy cogeneration positive influence inside banana pseudostem s biorefinery.
Análisis tecno-económico y ambiental de la obtención de biofertilizantes bajo el concepto de biorefinería a partir de residuos cítricos
(Universidad de Cuenca, 2015-12) Hernández, Valentina; Botero, Christian; Aristizábal, Valentina; Castro, Eulogio; Cardona, Carlos A.
High costs of inorganic fertilizers in Colombia have caused serious economic problems for the agrarian class, because these agricultural supplies are indispensable to obtain high production yields. Therefore, it is required to considerate alternatives in order reduce the costs associated with the agricultural activity in the country. This paper presents an economic and environmental analysis of the production of biofertilizers from citrus waste through anaerobic digestion. Two scenarios are studied: (1) the first one evaluates the production of limonene and pectin from orange peel, and (2) in the second one, in addition to the mentioned products in the first scenario, biofertilizers are obtained from the solid waste resulting from limonene and pectin production processes. In the first scenario, profit margins of 93% and 57% for pectin and limonene are obtained, respectively. For the second scenario, profit margins of 94%, 48% and 61% for pectin, limonene and bio-fertilizers were obtained, respectively. These results demonstrate that the second scenario is the best from the economic point of view. It is also shown that scenario two generates lower potential environmental impact, being the most environmentally friendly.
Aplicación de la termodinámica en la síntesis óptima de procesos químicos y biotecnológicos
(Universidad de Cuenca, 2015-12) Forero, Héctor; García, Carlos; Cardona, Carlos
Biomass appears as a promising alternative to produce environmentally friendly compounds with competitive advantages over non-renewable compounds. Bio-furfural is one of these compounds, and currently has become one of the most important and commonly used worldwide compounds. Alternatively, bio-furfural has been used as a building block to develop chemical platforms in order to produce some other compounds of industrial interest. This work implements the thermodynamic analysis of furfural production in a biorefinery from lignocellulosic biomass. Techno-economic, energy and exergy are evaluated in order to determine the economic and energy viability of this process. As a result, the production of furfural from sugarcane bagasse under the biorefinery concept has high economic profitability, besides other products can be used to increase the economic performance of the biorefinery. Additionally, plant or process sections with higher energy requirements and irreversibilities are determined. Alkaline and enzymatic hydrolysis were the processes with the highest irreversibilities, however, the plants for furfural and ethanol production has the highest energy needs related to the reaction and separation stage, respectively.
Application of multiscale entropy production theory to hydro-turbine maintenance
(Universidad de Cuenca, 2015-04-01) Jaramillo, María; Cortés, María; García, Luis; Hernández, Estefanía; Estrada, Jorge; Cano, Eduardo
Maintenance of hydro turbine would be easier if it could be measured the multi-scale of its sound and magnetic waves produced by the entropy, as an accepted indicator of the physical complexity of the system, it is proportional to the logarithm of the number of states in a thermodynamic system. The following methods were applied: Parametric solid modeling, FEA analysis, CFD simulation, CAD design & drafting, PLC & SCADA programming, protection engineering & testing, power quality testing and others techniques. This paper describes a new approach to qualify the final turbine well-working. The obtained results showed that the time sound wave series obtaines from the turbine suggests a rise of the hydro-turbine complexity with aging. As well, several concepts and techniques to quantify the magnetic and sound wave signal entropy are presented, which are aimed to assess the turbine performance. Such concepts are explored and some entropy vs age plotting are depicted to show the behavior of the sound waves taken nearby the hydro–turbines and alternators located in Manizales-Colombia.
Articulación de los actores del ecosistema emprendedor como herramienta efectiva para la transición de un proyecto emprendedor a un proyecto comercialmente viable
(Universidad de Cuenca, 2015-04-01) Zalamea Piedra, Silvana; Peña González, Silvia Alexandra
The productive matrix transformation to attain the Ecuador’s good living is an agreement point for our society. Entrepreneurs are considered to be an important part on the achievement of this change, they are importatnt to increase entrepreneurship and supporting organizations to be articulated. This research highlights the importance of a linkage among actors involved on entrepreneurship ecosystem based on “Quadruple Helix” model, which it will be possible a transition between an entrepreneur project and a commercially viable project. This investigation also studies several concepts and initiatives focus on the construction of entrepreneurship ecosystems proposed by international organisms and it is analyzed the steps through which an entrepreneurial idea which could succeed.
Avances en el proyecto “Determinación de la forma exacta de la tierra a través de MEMS en un Nano-Satélite”
(Universidad de Cuenca, 2016-04) Vázquez, J. Félix; Fernández, Tiburcio; Viniegra, F.
The following document illustrates the progress that has been made in the “Design and construction of a Nano-Satellite” project. It is currently under development at ESIME U.P. Ticoman, which is part of the Instituto Polit´ecnico Nacional. The Projects main objective is to give our students an introduction into Aerospace issues. The Nano-Satellite is a small cubic shaped devise measuring ten centimeters per side, with a one kilogram total weight. Its payload is a MEMS (Micro Electro-mechanical Systems) which will act as an electronic pendulum; this, combined with the gravitational potential harmonics, will allow us to determine the Earths true shape. The mathematical foundation, satellite components, preliminary structure design, manufacturing process, results of the structural destructive tests and static Analysis through the finite element method, are shown in this presentation.
Calidad en el servicio público: una experiencia personal de aprendizaje y adaptación
(Universidad de Cuenca, 2017) Tenesaca, Víctor
The Constitution of Ecuador (2008) in its article 227, talks about the principles governing public administration and among them stands out one that is familiar to every Industrial Engineer: quality. This article describes a personal experience in the public sector in the specific area of quality and for this purpose, two specific cases are presented: The first is the improvement plan for direct care units and under the agreement of the Ministerio de Inclusión Económica y Social, MIES, developed between the years 2014 and 2015 and that was elaborated by its Department of Service Quality staff. The other talks about the work done actually by the Department of Evaluation and Accreditation of Universities and Polytechnic Schools of the Consejo de Evaluación, Acreditación y Aseguramiento de la Calidad, CEAACES, for the improvement of higher education in Ecuador. First, it presents the tools and methods that were designed and used in order to solve problems in the area of social services and on second, the experience of working in an area of high complexity such as higher education. It is intended to show both the way in which a problem is solved through the design and construction of specific tools, as well as possible scenarios of performance and application of knowledge for the engineer.
Caracterización del proceso tradicional del pelado de maíz con ceniza con miras a la inocuidad alimentaria
(Universidad de Cuenca, 2016-09) Ochoa, María Cristina; Molina, María José; Astudillo, Gabriela; Donoso, Silvana; Ortiz, Johana
In Ecuador, as in the rest of Latin America, maize production and consumption is high (82,9 Kg/person/year). Maize is susceptible of contamination with mycotoxins, however, nixtamalization and similar peeling processes have the potential of detoxify the cereal. The objective of this study is to characterize and standardize the traditional process of peeling maize using ash in Ecuador. An exploratory study was performed I Nab´on-Ecuador from August to September 2014. Interviews were carried-out among 40 community members to collect data on maize peeling process. The Ecuadorian process “traditional process of wood ash nixtamalization” is performed as follows: it uses 1,450 grams of wood ash for each 2,500 grams of maize, this two ingredients are added to boiling water (4.8 liters) and the mixture is cooked during 0.5-1 hour with constant movement. Subsequently, the removal of the pericarp is performed by manual rub, then, the maize is subjected to soaking (12 hours) and drying (48-72 hours) processes. The standardization of the process could encourage the use of this traditional technique accessible to the community, keeping the organoleptic characteristics and ensuring food safety without increasing maize price in the market.
Comparación de modelos termodinámicos en el análisis topológico de mezclas
(Universidad de Cuenca, 2016-05) Forero, Héctor; Caballero, Ashley; García, Blanca; Castro, Agustín; Gómez, Alvaro; Pisarenko, Yuri; Cardona, Carlos
The objective of this paper is to introduce and propose a thermodynamic model appropriate for predicting the properties of the propanoate methyl – propionic acid – methanol – water mixture, resulting from the esterification of propionic acid. For this purpose, a topological analysis is carried out from phase equilibrium calculation and azeotropy evaluation, considering three thermodynamic models and mixing rules (PCSAFT, PRWS and PSRK). Based on the performed analysis, it was found that the predictive model Soave Redlich Kwong, is the most appropriate for the studied mixture since it predicts the azeotropes that are reported in practice. In addition, the conceptual analysis of the trajectories of process shown in the residue curves was performed and a process trajectory for obtaining the products in a distillation tower according to the required design considerations was established.
Costo/beneficio un modelo estratégico para el gestor de la seguridad y salud ocupacional
(Universidad de Cuenca, 2017) Ledesma, Fabián; Barragán Landy, Milton Francisco
This paper presents a technical-economic model for managers of occupational health and safety, whose purpose is to determine the feasibility of taking decisions in preventive projects that require investment. The methodology used is based on systematic operations, which allow to perform the respective calculations for the solution of a problem. The model begins with the identification of hazards, measures and evaluates the risk to later propose control measures in function of two decision currents; the first relates to productivity and the second to cost-benefit that converge in the acceptance or rejection of control measures in terms of profitability and return on investment. The proposal was applied in an organization of the city of Cuenca - Ecuador in which the work of an operator was evaluated when a task is carried out in its current environment and after having taken preventive measures; cash flows were also determined on the basis of cost and expense items caused by an accident or occupational disease, owing to the omission by the organization of the legislation which imposes penalties and fines for employer liability.
Costos exergéticos de una turbina de gas considerando los gases de escape como pérdida o residuo variando la relación de presiones
(Universidad de Cuenca, 2015-04-01) Aguilar, Ignacio; Lugo, Raúl; Torres, Edgar; Lugo, Helen; Ambriz García, Juan J.
This paper presents a gas turbine engine parametric performance analysis. The aim of this work is to determine the influence of the compressor pressure ratio of the exergetic costs of all energy streams, assuming the exhaust gases as a waste or a residue. If the exhaust gases are considered as a waste, its exergetic cost is zero; and if it is treated as residue, the exergetic cost is no null. The highest exergetic cos t is associated to the exhaust gases stream of the exit of the combustion chamber. This cost is mainly affected by treating the exhaust gases as a waste or as a residue. For the optimum compressor pressure ratio related to the maximum thermal efficiency of 40.05, the exergetic cost of the stream at the exit of the combustion chamber is about 787618 kW, if the exhaust gases are assumed as a waste. If they are considered as a residue the mentioned exergetic cost presents an increment of 15.66% for the same compressor pressure ratio.

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