The Sahara Desert is one of the main sources of particulate matter (PM) in the world. This PM has the ability to affect air quality thousands of miles from the source. The intrusions of this dust in the Caribbean are well documented; however, no intrusions of this pollutant have been reported in large Colombian cities. This article analyses and determines the possible relationship between the emissions of dust from the Sahara, and an episode of high pollution that occurred in Bogotá and Medellín at the end of June 2014. The data recorded by the air quality networks of Bogotá and Medellín, the dust column mass density of the Merra-2 project, and the results of the NMMB/BSC-Dust model were used. The origins and trajectories of air masses were tracked by implementing HYSPLIT. The aerosol subtype was obtained from the CALIOP-CALIPSO sensor.

Chemical compositions obtained by XRF from clay and fly ash from coal combustion in a hive furnace are reported. The quantities of clay, fly ash and magnesium sulphate (MgSO₄ · 7H₂O) were selected according to their chemical composition to achieve total efflorescence on the surface of the brick (solid ceramic unit). Once the masonry units were formed by pressing, they were treated at 400 °C for two hours to remove moisture, and once they reached 950 °C, they were cooked at this temperature for three hours. The chemical composition of the efflorescence on the surface of the specimens was established by XRF, the cross section of a brick was morphologically analyzed and, finally, the specimens were subjected to compression tests to determine their resistance and maximum water absorption, taking into account Colombian technical standard NTC 4205.

This paper presents the results of the kinetics of combustion by thermogravimetry of briquettes prepared with residues of vine shoots, skins, stalks and seeds, obtained from the cultivation and processing of Isabella grapes (Vitis labrusca L.). The briquettes were prepared by compression and characterized by near analysis, elemental analysis and thermogravimetric analysis (TGA). The TGA was carried out at three heating rates and in air atmosphere. With the results of the TGA the activation energy was determined by the Iso-conversion methods of Starink and Friedman, and the order of reaction by the Avrami method. The Starink method was found to be more accurate than the Friedman method in calculating activation energy. In addition, reaction order values are very similar for the residues and mixtures analyzed.

The construction of reinforced concrete strip road pavements has increased in Colombia in recent years. The vast majority of the projects are based on the 500-1P specification, which presents a general design, of which the criteria taken into account in its elaboration are unknown, which generates many doubts for its use in different projects. In the present article, an analysis of strip road pavement is made and recommendations are given for the design and construction of this type of pavement, taking into account current conditions of use, expected loads, characteristics of the supporting soil, and qualities of materials.

Tropical areas are regions subject to warm environments and their soils, especially in areas covered with vegetation, may be exposed to events such as fires. The high temperatures that can be reached in these events cause variations in some of the geotechnical properties of soils, influencing the behavior of the material, and can give rise to erosive processes, which in many cases precede mass movements. The following article describes what happens in a soil that has undergone an ignition process in the laboratory, analyzing the variations in some physical (moisture content, Atterberg limits, specific gravity and granulometry), chemical (pH and cation exchange capacity), mineralogical, structural and mechanical (suction, disintegration and pinhole test) properties; clearly showing that the material becomes more acidic with a higher void ratio, less cation exchange capacity, less kaolinite, plasticity and suction, and variation in texture, with a consequent increase in erodibility.

The objective of this article is to analyze the evolution and the relationship between investment and road infrastructure and the economic development of Colombia, making a comparison with some Latin American countries. Furthermore, the relationship through macroeconomic indicators and road infrastructure is established, including Colombia’s competitiveness compared to neighbor countries. In order to achieve this, the historical records are analyzed through different generations of concessions which have been created between 1993 and 2014; the article is further intended to review the bibliography associated to the international tendency to involve more participation of private sector in the development of road infrastructure projects through public and private associations as the specific involvement mechanisms.

Software engineering is a discipline oriented to the definition of methods, techniques and tools for developing software products in an efficient and rapid way. Growing demand of such products generates the need of a large amount of software engineers with the technical and social competencies required by software industry. This situation is a challenge for Higher Education Institutions in terms of a training process of future professionals of this discipline. In this sense, such institutions are exploring active teaching strategies for promoting the needed competencies in students. However, an integrated proposal of these teaching approaches is still underdeveloped. In this paper, the authors present a proposal for representing practices for teaching and learning software engineering, oriented to identify the main concepts included in any type of these practices. The proposal is based on the Semat kernel –Essence standard– as universal framework for representing software engineering practices, defining an extension to such kernel. Finally, we present a representation example of a software engineering teaching and learning practice using the Semat Kernel Extension proposed.

Requirements solicitation is considered the basis for the next stages of software development, and involves, among others, collecting and analyzing functional and non-functional requirements (FNR). The literature shows that: (i) there is a lack of NFR elicitation mechanisms and (ii) there is a lack of awareness of NFR by stakeholders. In this sense, this article presents the framework for the tendering of non-functional requirements based on knowledge management (called Merlinn) that seeks the visualization of NFRs and the active participation of stakeholders. Merlinn’s evaluation was conducted through a study case in a software development company. The results of the evaluation show that Merlinn can be ideal and adaptable to support the organization’s NRF tendering process, so that it impacts the quality of the software product.

This paper proposes a methodology for the analysis of power quality in industrial electrical installations. Initially, a multipoint measurement is performed, then the phenomena that most affect the industry are identified and analyzed, then the system is modelled and adjusted to the real behavior, and some solutions are proposed and simulated. Subsequently, a case study is selected and the power quality study is carried out on the basis of the proposed methodology and according to the parameters of the NTC 5001 standard. Finally, the advantages of using multipoint measurement and modeling in power quality studies are established.

In this scientific research article, the community interested in digital image processing is introduced to the new application of Radon’s transformation to segment images in grayscale, which allows the identification and classification of regions or objects, which can be extended to color images. Results obtained were compared with the results of two classic segmentation algorithms: the optimized Otsu thresholding algorithm, and the Seeded Region Growing growth algorithm.