51 research outputs found

    Challenges in Bioenergy Production from Sugarcane Mills in Developing Countries: A Case Study

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    Worldwide energy policies are moving towards a reduction of fossil fuels’ share in the energy mix and to invest in renewable and green energy sources. Biomass is one of these, and it represents, in the form of sugarcane, a strategic source in Colombia, especiallyin the Valle del Cauca. In this region, the sugarcane industry is able to convert the energy content of the cane into different energy products, such as ethanol, electricity, and high-pressure steam, which are cogenerated via bagasse combustion. In this work, the case of a sucrose and ethanol production plant, which mills ten thousand tons of sugarcane per day, is considered. A tailor-made computational model was developed to assess the energy and material process balances in order to estimate the effect of different operating conditions on cogeneration boilers and turbines, and to optimize the overall process efficiency. The current situation was modeled with good precision from the developed model. Likewise, the concept of “Renewable Efficiency” was introduced to explain the degree of green power, which a process plant is able to produce. Consequently, new innovative solutions and process layouts were proposed in order to increase their renewable efficiency. With the new configurations, a convenient energy surplus of up to 33 MW can be reached, which could be sold in the national electricity grid, representing long-term interesting economic benefits for the company

    Fuzzy approach for risk assessment of brominated flame retardants in aquatic ecosystems

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    Brominated flame retardants (BFR) are pollutants that represent a threat to both human health and environment due to their industrial use, their persistence and their ability to bioaccumulate and biomagnify in food chains, especially in the aquatic one. For the last ten years contamination levels for this type of compounds have been reported for European, North American and Asian human tissue, sediments and biota samples [1-3]. However, monitoring efforts into the assessment of BFRs contamination levels in Latin America are scarce. In this study, a model for the evaluation of the environmental risk of BFRs in the aquatic ecosystems has been developed. It has been based on a technical application of the Fuzzy Theory [4]. In particular, three interconnected Fuzzy Inference Systems (FIS) have been created through the use of the Fuzzy Toolbox in Matlab. In order to improve and make the model scientifically robust, several international experts have been questioned about different information required to build the fuzzy system. Information from 38 questionnaires have been collected and statistically treated.Preprin

    Revision of Tympanopleura Eigenmann (Siluriformes: Auchenipteridae) with description of two new species

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    The Neotropical catfish genus Tympanopleura, previously synonymized within Ageneiosus, is revalidated and included species are reviewed. Six species are recognized, two of which are described as new. Tympanopleura is distinguished from Ageneiosus by having an enlarged gas bladder not strongly encapsulated in bone; a prominent pseudotympanum consisting of an area on the side of the body devoid of epaxial musculature where the gas bladder contacts the internal coelomic wall; short, blunt head without greatly elongated jaws; and smaller adult body size. Species of Tympanopleura are distinguished from each other on the basis of unique meristic, morphometric, and pigmentation differences. Ageneiosus melanopogon and Tympanopleura nigricollis are junior synonyms of Tympanopleura atronasus. Tympanopleura alta is a junior synonym of Tympanopleura brevis. A lectotype is designated for T. brevis. Ageneiosus madeirensis is a junior synonym of Tympanopleura rondoni. Tympanopleura atronasus, T. brevis, T. longipinna, and T. rondoni are relatively widespread in the middle and upper Amazon River basin. Tympanopleura cryptica is described from relatively few specimens collected in the upper portion of the Amazon River basin in Peru and the middle portion of that basin in Brazil. Tympanopleura piperata is distributed in the upper and middle Amazon River basin, as well as in the Essequibo River drainage of Guyana

    4to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

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    Este volumen acoge la memoria académica de la Cuarta edición del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2017, desarrollado entre el 29 de noviembre y el 1 de diciembre de 2017 y organizado por la Universidad Politécnica Salesiana (UPS) en su sede de Guayaquil. El Congreso ofreció un espacio para la presentación, difusión e intercambio de importantes investigaciones nacionales e internacionales ante la comunidad universitaria que se dio cita en el encuentro. El uso de herramientas tecnológicas para la gestión de los trabajos de investigación como la plataforma Open Conference Systems y la web de presentación del Congreso http://citis.blog.ups.edu.ec/, hicieron de CITIS 2017 un verdadero referente entre los congresos que se desarrollaron en el país. La preocupación de nuestra Universidad, de presentar espacios que ayuden a generar nuevos y mejores cambios en la dimensión humana y social de nuestro entorno, hace que se persiga en cada edición del evento la presentación de trabajos con calidad creciente en cuanto a su producción científica. Quienes estuvimos al frente de la organización, dejamos plasmado en estas memorias académicas el intenso y prolífico trabajo de los días de realización del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad al alcance de todos y todas

    Water quality analysis in rivers with non-parametric probability distributions and fuzzy inference systems: Application to the Cauca River, Colombia

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    10.1016/j.envint.2012.11.007The integration of water quality monitoring variables is essential in environmental decision making. Nowadays, advanced techniques to manage subjectivity, imprecision, uncertainty, vagueness, and variability are required in such complex evaluation process. We here propose a probabilistic fuzzy hybrid model to assess river water quality. Fuzzy logic reasoning has been used to compute a water quality integrative index. By applying a Monte Carlo technique, based on non-parametric probability distributions, the randomness of model inputs was estimated. Annual histograms of nine water quality variables were built with monitoring data systematically collected in the Colombian Cauca River, and probability density estimations using the kernel smoothing method were applied to fit data. Several years were assessed, and river sectors upstream and downstream the city of Santiago de Cali, a big city with basic wastewater treatment and high industrial activity, were analyzed. The probabilistic fuzzy water quality index was able to explain the reduction in water quality, as the river receives a larger number of agriculture, domestic, and industrial effluents. The results of the hybrid model were compared to traditional water quality indexes. The main advantage of the proposed method is that it considers flexible boundaries between the linguistic qualifiers used to define the water status, being the belongingness of water quality to the diverse output fuzzy sets or classes provided with percentiles and histograms, which allows classify better the real water condition. The results of this study show that fuzzy inference systems integrated to stochastic non-parametric techniques may be used as complementary tools in water quality indexing methodologies

    Assessing interactions among students geographically disperse during multinational design projects

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    The new business model and global operations of many enterprises have brought new challenges for engineers working in multinational companies. These new trends and the need of educating world-class engineers with global competencies have opened opportunities for new educational models to expose students to international experiences to start developing those capabilities. One pedagogical activity used to promote global competencies is the participation of students in multinational design projects, which is a problem-based learning approach in an international setting, where students get immersed in the solution of an engineering design task while they work in teams and collaborate with international partners. Consequently, a collaborative network of institutions from the Americas and Italy has developed and executed collaborative multinational design projects as part of academic experiences for their students. The main goal of these projects is to foster international collaboration and to offer an opportunity to the students to develop professional skills through international teamwork effort in the solution of a design problem. However, a real challenge of this practice has been to create an effective interaction among the students participating in this type of projects and to maintain the flow of information, and student engagement in the project and in their learning. Therefore, this paper reports the work related to an assessment approach used to monitor students' interaction in multinational collaborative projects. The main objectives of the proposed assessment tool are: (a) to evaluate the interaction among the students (frequency, quantity and quality); (b) to determine the value of social interaction in the flow of the interaction; (c) to determine the impact of interaction in the development of the project
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