Respetado lector: Es un placer entregarle nuestro número 26 de Revista Ingenierías Universidad de Medellín, a partir del cual la revista hace un punto de inflexión.
A partir del momento, nuestro reto consiste en incrementar nuestra capacidad de respuesta con miras en el corto plazo a cambiar nuestra periodicidad de circulación. En un futuro cercano apareceremos cada cuatro meses, tres veces por año con el fin de darle mayor agilidad a la producción editorial, tener contenidos más actualizados y al tiempo, darle inicio a un proceso de mejora continuada con el fin de elevar nuestra visibilidad en el SciELO Citation Index de Web of Science, en donde ya aparecemos, y aspirar a ingresar en el sistema SCOPUS de Elsevier.
This research are discussed the results of the physical and chemical variables, SO4-2, Cl-, pH and conductivity of rainwater in ten sites in the city of Popayan, Colombia. The results were determined by the technique of total deposit from September 2011 to February 2012. The objective was: to evaluate the sensitivity to acid rain formation considering possible sources of certain ions. The results were analyzed according to the spatial and temporal variability and its values were attributed to natural sources such as volcanic influence aerosols emitted from the ground and drag sea salt from the Pacific Ocean as possible sources of ions SO4-1yCl-. Results are also explained by anthropogenic inputs.
The Andean wetlands are fragile ecosystems that play a key role in hydrological, cultural, ecological and socioeconomic dynamics of the Colombian Andean region; to continue to deteriorate for reasons associated with climate change and the pressure generated by human activities. Its preservation has aroused the interest of many actors who seek conceptual, assessment tools and management options that allow the management processes of these ecosystems through new insights and understandings about mitigation and adaptation to future changes. This paper seeks a review of some references about the degradation processes of the Andean wetlands, exhibit trends in vulnerability analysis and highlight the current challenge of developing the analysis through a vision that integrates social and biophysical, from a systemic approach of important natural systems. In order to introduce the vision of socio-ecological systems or socio-ecosystems as a known alternative, but that must be developed and appropriate for implementation and understanding of human communities.
Young people of popayan city facing climate change. A study from the social representations
Nilsa Lorena Alvear-Narváez, Victoria Eugenia Ceballos Sarria, Maricela Urbano Bolaños
This research was conducted under the project “Representations to Climate Change: Knowledge, Beliefs and Behaviors of the community in the municipality of Popayán”, implemented by the Environmental Studies Group (GEA) at the University of Cauca. Its purpose was to explore the representations addressing climate change in an urban population, as a reference basis for proposing criteria in formulating strategies for education programs in climate change research that develops, such as “Environmental Monitoring for Climate Change High Andean Agricultural ecosystems (MACACEA) “. In this case study through an instrument demoscopic population between 15 and 29 years of age residing in urban area of Popayan, core issues regarding climate change is presented as: knowledge and beliefs about causes, processes and consequences of climate change, and the importance attributed sources
The challenge of using renewable energy sources means that the production of biofuels and the design of their supply chains, should be pursue environmental and social benefits beyond the purely economic benefit. In this paper are revised some discussions about the impact of biofuels on sustainability and researching in the biofuel supply chains design of first and second generation via mathematical optimization, to analyze how environmental and social concerns have been considered in this problem. Finally, techniques most used optimization were identified and the review found that the concept of sustainability in the design of biofuel supply chains through modeling, is just beginning.
Microwave assisted roasting for enhanced processing of Colombian gold mining samples
Iván Amaya, William Botero, Rodrigo Correa
This research article, supported by Universidad Industrial de Santander (Vicerrectoría de Investigación y Extensión), shows the results achieved after using the electromagnetic cavity of a microwave oven and a temperature measurement system, to heat a mineral sample from the mining district of Vetas, in order to see if it was possible to induce a cheaper processing. A factorial design of experiment (DOE) was used to observe the effect of the microwave power, the exposure time and the sample’s mass. It was found that an energy consumption reduction of 81.7%, and a time reduction of 75%, were possible to achieve while maintaining the recovery margin at 90% of the achieved with a traditional roasting, at lab level. Thus, it can be concluded that, at least for this ore, microwave roasting of the sample is viable at this scale. Moreover, if a better applicator were to be used, the benefits could be enhanced even more, so it is encouraged as a next step.
Evaluation of a customer loyalty strategy with system dymamics
Stefanía Peña Escobar, Gloria S Ramírez Reyes, Juan C Osorio Gómez
The customer loyalty programs are a tool of differentiation and high impact to create long term relationships with customers of a company, so as to achieve an improvement in the portfolio and collections, reduced costs of customer service, increased revenue from higher sales to the most profitable customers, cross selling, among many other benefits. Accordingly, we present a system dynamic model to analyze the economic benefits, in terms of profitability, which would be to implement a customer loyalty strategy. To adjust and validate the proposed model, its implementation is done in a real case of a marketer of agricultural products in the department of Valle del Cauca - Colombia. The simulation results show that indeed the model fulfills its purpose, and that the loyalty program achieved significant results in the finances of the organization.
Equilibrium, thermodynamic and kinetic models for the adsorption of red 40 onto corn cob
Danilo Figueroa, Anderson Moreno, Angelina Hormaza
Adsorption is a widely used method for treatment of dissolved pollutants. Diverse agro-industrial wastes have been explored as potential adsorbents, showing high efficiency in the removal of dyes. To scale this process kinetic and equilibrium models for each pair adsorbate-adsorbent are required. In this work the equilibrium, kinetics and thermodynamic of the corn cob - red 40 system under batch system at pH 2.0 at temperatures of 25, 40 and 55 °C were evaluated. Langmuir, Freundlich and Temkin models were selected to represent the isotherms, while Lagergren, Ho and Elovich equations for kinetics of the process. Freundlich model provided the best fit to the isotherms, while the adsorption kinetics was best described by the Ho equation and the values for the Gibbs free energy and entropy indicated the spontaneity and feasibility of the process.
Horizontal balancing for mixed models assembly lines
Luis Felipe Durango Cruz, Juan Pablo Orejuela Cabrera, Luis Alberto Ortiz Dorado
Traditionally assembly lines have been used to produce high volumes of a single model. To take advantage of these lines in flexible manufacturing environments, we can implement mixed model lines which allow manufacturing different products of a family in the same line, however, its balancing requires different techniques that traditional. In this research, a literature review was made to analyze the factors affecting the mixed model lines in MTO environments and based on this we developed a mathematical optimization model to stabilize workloads making easier the decision about production sequences that are programmed on the line. The model was run in several instances and the results were significantly better than those obtained with a line balancing traditional method.
Curvature-based remeshing methodology oriented to human face 3D models
Marco Jinete, Flavio Prieto, Augusto Salazar
Remeshing techniques seek to modify a mesh in order to adapt it to an specific application. This work proposes a remeshing methodology specialized in the human face, whose purpose is to reduce the number of faces and vertices that requires the mesh, keeping the characteristics of the human anatomy. Curvature information that highlights the intrinsic anisotropy of natural geometry or geometry of human origin is used to accomplish this. Results were polygonal anisotropic meshes, composed mainly of quadrilaterals, with less than 50% of the points and faces of the initial mesh, that maintain the anatomical features for models of the face in a neutral expression, or expressions of happiness, disgust, fear, angry, surprise, and sadness. The methodology was validated with models from the BU-3DFE database, and the quality of the obtained results were evaluated against the remeshing achieved when a technique of simplification based on quadric error metrics is used
Overfitting control inside cascade correlation neural networks applied to electricity contract price prediction
Fernán A Villa G, Juan D Velásquez H, Paola A Sánchez S
Prediction of electricity prices is considered a difficult task due to the number and complexity of factors that influence their performance, and their relationships. Neural networks cascade correlation - CASCOR allows to do a constructive learning and it captures better the characteristics of the data; however, it has a high tendency to overfitting. To control overfitting in some areas regularization techniques are used. However, in the literature there are no studies that: i) use regularization techniques to control overfitting in CASCOR networks, ii) use CASCOR networks in predicting of electrical series iii) compare the performance with traditional neural networks or statistical models. The aim of this paper is to model and predict the behavior of the price series of electricity contracts in Colombia, using CASCOR networks and controlling the overfitting by regularization techniques
A multi level approach for business process retrieval
Cristhian Figueroa, David Camilo Corrales, Juan Carlos Corrales
Nowadays business process reuse is critical in companies that need to build flexible and service-based business solutions in order to react quickly and cost-effective to dynamic market-conditions. For this reason, many companies have implemented approaches to find relevant business processes to be reused to create new software solutions performing required business functionalities. This paper presents a multilevel retrieval approach that detects linguistic, structural, and behavioral properties to increase the precision level in recovering those business processes stored in a repository.