bluuebunny/crossref_metadata_2025 huggingface dataset:
Producing fuel alcohol by extractive distillation: Simulating the process with glycerol
Authors: Uyazán Ana María , Gil Iván Dario , Aguilar Jaime , Rodríguez Niño Gerardo , Caicedo Mesa Luis A
Published: August 2022

Downstream separation processes in biotechnology form part of the stages having most impact on a product's final cost. The tendency throughout the world today is to replace fossil fuels with those having a renewable origin such as ethanol; this, in turn, produces a demand for the same and the need for optimising fermentation, treating vinazas and dehydration processes. The present work approaches the problem of dehydration through simulating azeotropic ethanol extractive distillation using glycerol as separation agent. Simulations were done on an Aspen Plus process simulator (Aspen Tech version 11.1). The simulated process involves two distillation columns, a dehydrator and a glycerol recuperation column. Simulation restrictions were ethanol's molar composition in dehydrator column distillate and the process's energy consumption. The effect of molar reflux ratio, solvent-feed ratio, solvent entry and feed stage and solvent entry temperature were evaluated on the chosen restrictions. The results showed that the ethanol-water mixture dehydration with glycerol as separation agent is efficient from the energy point of view.
Manufacturing and automation
Authors: Córdoba Nieto Ernesto
Published: August 2022

The article presents concepts and definitions from different sources concerning automation. The work approaches automation by virtue of the author's experience in manufacturing production; why and how automation projects are embarked upon is considered. Technological reflection regarding the progressive advances or stages of automation in the production area is stressed. Coriat and Freyssenet’s thoughts about and approaches to the problem of automation and its current state are taken and examined, especially that referring to the problem's relationship with reconciling the level of automation with the flexibility and productivity demanded by competitive, worldwide manufacturing.
UN_PAT: a software for calculating transient grounding potential
Authors: Hernán Montaña Johny , Duarte Velasco Óscar Germán , Sarmiento Ángela Maria , Marín Michael Andrés , Torres Horacio
Published: August 2022

This paper presents results from work done at the National University of Colombia and from a PhD thesis written there. This work was aimed at implementing software for analysing the transient behavior of any configuration of grounding system buried in lineal, homogeneous and isotropic soil. The hybrid electromagnetic model (HEM) was used because it presents high versatility and low computation time. The UN_PAT software was written in C+ +; it used free libraries with the aim of being free software so that it could be modified and improved in future work. The software results were validated with other software, with results from another analysis model and experimental results; some of these comparisons are given in this paper.
Metaheuristics applied to vehicle routing. A case study. Part 1: formulating the problem
Authors: González Vargas Guillermo , González Aristizábal Felipe
Published: August 2022

This paper deals with VRP (vehicle routing problem) mathematical formulation and presents some methodologies used by different authors to solve VRP variation. This paper is presented as the springboard for introducing future papers about a manufacturing company’s location decisions based on the total distance traveled to distribute its product.
Contamination by urban superficial runoff: accumulated heavy metals on a road surface
Authors: Zafra Mejía Carlos Alfonso , Temprano González Javier , Tejero Monzón Juan Ignacio
Published: August 2022

Studying the behavior of accumulated contamination on urban surfaces is important in designing control methods minimising the impacts of surface runoff on the environment. This paper presents data regarding the sediment collected on the surface of an urban road in the city of Torrelavega in northern Spain during a period of 65 days during which 132 samples were collected. Two types of sediment collection samples were obtained: vacuumed dry samples (free load) and those swept up following vacuuming (fixed load). The results showed that heavy metal concentration in the collected sediment (Pb, Zn, Cu and Cd) was inversely proportional to particle diameter. High heavy metal concentrations were found in the smaller fraction (63 µm). Regression equations were calculated for heavy metal concentration regarding particle diameter. Large heavy metal loads were found in the larger fraction (125 µm). The results provide information for analysing runoff water quality in urban areas and designing treatment strategies.
A new method for designing floor slabs on grade due to the difficulty of applying simplified design methods, amongst them being the Portland Cement Association (PCA) and Wire Reinforcement Institute (WRI) methods
Authors: Camero Sanabria Hugo Ernesto
Published: August 2022

This article presents a methodology for designing slabs on grade for industrial floors where there is an eccentricity between the slab centroid and the gravity center loads of the loaded axle of forklift trucks travelling over the floor. An example was used for analyzing how Portland Cement Association (PCA) and the Wire Reinforcement Institute (WRI) methods are inadequate for designing floors subjected to this condition. The new proposal for designing slabs on grade for industrial floors has been called the Camero method. An example of an industrial floor designed to be capable of sustaining an infinite number of load applications (or 50-year life) was compared to the results of the Camero method and PCA and WRI’s simplified methods. Industrial floors should be capable of sustaining an infinite number of load applications (50-year lite) if designed with the Camero method; on the other hand, if designed using PCA and WRI methods they will only last one year (in this example the number of axle load applications in a 1-year period was equal to the number of allowable repetitions) because they will not be able to sustain an infinite number of load applications. It was concluded that designing plain concrete slabs (without reinforcement) on grade according to PCA and the WRI methods leads to slab fatigue, even though extreme fiber stress should not exceed 50 percent (50%) of static modulus of concrete rupture and slabs should sustain an infinite number of load repetitions (infinite amount of forklift truck traffic) were considered parameters in their design.
Ethyl ester production from (RBD) palm oil
Authors: Martínez Ávila Oscar Mauricio , Sánchez Castellanos Francisco José , Suárez Palacios Oscar Yesid
Published: August 2022

This work develops a methodology for obtaining ethyl esters from RBD (refined, bleached and deodorised) palm oil by evaluating the oil’s transesteritication and separation. Two catalysts were first tested (KOH and NaOH) by studying the effect of water presence on the reaction. The separation process was then evaluated by using water and water-salt and water-acid mixtures, establishing the agent offering the best results and carrying out the purification stage. Raw materials and products were characterised for comparing the latter with those obtained by traditional means and verifying the quality of the esters so produced; minimum differences were found between both. The proposed methodology thus allows esters to be used as raw material in petrochemical industry applications. A more profitable process can be obtained compared to those used today, given the amounts of separation agent so established (1% H3PO4 solution, in water). The overall process achieved 74.4% yield, based on the oil being used.
Analysing polystyrene-modified asphalt and its incidence in a heat-dense asphalt mixture
Authors: Figueroa Infante Ana Sofía , Reyes Lizcano Fredy Alberto , Hernández Barrera Diana , Jiménez Christian , Bohórquez Natalia
Published: August 2022

This article presents some results obtained with an MDC-2 asphalt/polystyrene-modified asphalt mixture as a result of crushing waste glass. The stone, asphalt and polystyrene materials’ were characterised for drawing up the design. The Marshal method was used for obtaining the best asphalt-stone-polystyrene percentages. The Superpave method was used for analysing the asphalt; the mixture’s dynamic behavior was analysed using a test involving 20°C and 30°C trapezoidal fatigue for 90x10-6, 150x10-6 and 220x10-6m deformation. The truck-wheel test was analysed for a 13-ton load, similar to that of the heaviest axle on a Transmilenio (articulated) bus. The dynamic module test was analysed for 15°C, 20°C and 30°C and 2.5, 5 and 10 Hz frequencies. Conventional asphalt mixture and modified asphalt results were contrasted, interesting behavior being observed regarding plastic deformation of the modified mixture in service.
Training a multilayer neural network for the Euro-dollar (EUR/ USD) exchange rate
Authors: Villamil Torres Jaime Alberto , Delgado Rivera Jesús Alberto
Published: August 2022

A mathematical tool or model for predicting how an economic variable like the exchange rate (relative price between two currencies) will respond is a very important need for investors and policy-makers. Most current techniques are based on statistics, particularly linear time series theory. Artificial neural networks (ANNs) are mathematical models which try to emulate biological neural networks’ parallelism and nonlinearity; these models have been successfully applied in Economics and Engineering since the 1980s. ANNs appear to be an alternative for modelling the behavior of financial variables which resemble (as first approximation) a random walk. This paper reports the results of using ANNs for Euro/USD exchange rate trading and the usefulness of the algorithm tor chemotaxis leading to training networks thereby maximising an objective function re predicting a trader’s profits. JEL: F310, C450.
Inspección de piezas 3D: revisión de la literatura
Authors: Eleázar Jaramillo Andrés , Prieto Flavio , Boulanger Pierre
Published: August 2022

En este artículo se presenta una revisión sobre los sistemas de inspección presentados en la literatura, entre 2000 y 2006, que emplean mediciones de rango como fuente de información para realizar el control de calidad sobre diferentes objetos o productos. Los sistemas de inspección citados se clasificaron de acuerdo a las técnicas empleadas en la etapa de adquisición. Se describen las aplicaciones específicas de inspección consideradas en los trabajos citados, así como las características más relevantes de los sistemas desarrollados. A partir de dichas características se identifican las tendencias que se presentan en tales desarrollos, como son: la búsqueda de mayor flexibilidad, basadas en el uso de modelos CAD; y el uso preferente de sistemas de triangulación activa, en especial con proyección de luz estructurada en plano de luz y franjas, en vez de los sistemas pasivos. Finalmente, se plantea el problema de la inspección de piezas deformables, el cual representa un tema abierto a considerar para el desarrollo de futuros sistemas de inspección, y se discuten los trabajos más relevantes relacionados con este tema.
Analysing limits for human exposure to electromagnetic fields in accordance with ITU- k.52 standard for frequencies between 10 kHz and 3 GHz in urban areas of Bucaramanga
Authors: Rugeles Uribe José de Jesús , Jaimes Oviedo Antonio , Sánchez Barón Víctor Hugo , Mantilla Prada Oscar Alberto , Sastoque Gálvez Eduard
Published: August 2022

This article presents an overview of the results obtained from testing the limits of human exposure to 10KHz to 3GHz frequencies in the city of Bucaramanga (Colombia), taking into account decree 195-2005 approved by the Colombian Ministry of Communications, based on International Telecommunication Union (ITU) recommendation K.52. Measuring levels of exposure to electromagnetic radiation at three chosen locations in the city considered to be sensitive did not reveal that exposure limits were being exceeded. Mobile phone, modulated amplitude emission, frequency modulation and television bands installed at the sites several years ago were also measured. Levels obtained from electric field strength exceeded 100 dBuV / m in all cases, maximum value being 139 dBuV / m. Levels were well below exposure limits established by the K-52 rule. The highest levels for the general public’s exposure were 1.74964% in the AM band and 0.006408% for the cellular band between 869 and 894 MHz. This article also contains a description of the modules, exposure limits, acquisition and geo-positioning using the EspecVIEW tool designed for performing several types of measurements by Ministry officials and used in this study.
A review of physical-chemical parameters as water quality and contamination indicators
Authors: Samboni Ruiz Natalia Eugenia , Carvajal Escobar Yesid , Escobar Juan Carlos
Published: August 2022

More environmental agencies, universities and institutes are turning to the water quality and contamination index to facilitate interpreting physical, chemical and biological data, thereby leading to evaluating resource by means of a mathematical expression representing all evaluated parameters. Constructing and applying any indicator is specific for each region or individual source; however, its construction basically consists of three fundamental steps: selecting variables, determining subscripts for each parameter and choosing the formula for adding it. The variables considered in this process are: pH, dissolved oxygen, biochemical oxygen demand (BOD), total nitrogen form, phosphates and total solids (TS). Their use cannot thus be generalised since subjective judgements would thus be made; also, a system’s dynamics could not be evaluated using a single indicator, which is why studying each variable individually is also important. This article presents a review of the literature regarding water quality and contamination indexes used in some American and European countries and their design and interpretation based on physical and chemical parameters for evaluating them.
Enterprise-process: computer-based application for obtaining a process-organisation matrix during strategic information system planning
Authors: Rondón José Alirio , Cortés Aldana Félix Antonio , Zárate Caro Edisson
Published: August 2022

A lot of material has been published about strategic information system planning (SISP) methodologies. These methods are designed to help information system planners to integrate their strategies with organisational strategies. Classic business system planning for strategical alignment (BSP/SA) theory stands out because it provides information systems with a reactive role regarding an organisation’s objectives and strategy. BSP/SA has been described in terms of phases and the specific tasks within them. This work was aimed at presenting a computer-based application automating one of the most important tasks in BSP/SA methodology (process-organisation matrix). This matrix allows storing information about the levels of present responsibilities in positions and processes. Automating this task has facilitated students’ analysing the process-organisation matrix during SISP workshops forming part of the Systems Management course (Systems Engineering, Universidad Nacional de Colombia). Improved results have thus arisen from such workshops. The present work aims to motivate software development for supporting SISP tasks.
A procedure for hardening steel 45 by plastic deformation using a simple roller
Authors: Fernández Columbíe Tomás , Rodríguez González Isnel , Alcántara Borges Dayanis , Fernández Esther
Published: August 2022

This work presents the techniques used in an experimental design leading to evaluating the behavior of an independent variable force (P), ranging from 500 up to 2500 N, 27 minimum revolution number (n), average 54 and maximum 110 rev/min and 0.075, 0, 125 and 0.25 mm/rev advance for determining the dependent hardness (H) pattern when AISI 1045 steel test tubes were subjected to surface rolling for creating a compressive state deforming and increasing its resistance to abrasive wear and fatigue. The variables involved in the process were statistically analysed, revealing increased hardness ranging from 220 up to 262 HV. Optical microscopy was used for analysing the effect of hardening caused by deformation, establishing a mechanism for hardening steel by the elements in the crystalline network sliding due to burnishing.
Sol-gel synthesis of iron catalysers supported on silica and titanium for selectively oxidising methane to formaldehyde
Authors: Guerrero Fajardo Carlos Alberto , Sánchez Castellanos Francisco José , Roger Anne Cécile , Courson Claire
Published: August 2022

Iron materials supported on silica were prepared by the sol-gel method for evaluating catalytic activity in selective oxidation of methane to formaldehyde. Four catalysts were prepared, one corresponding to the silica support (catalyst 1S), another to the titanium support (catalyst 1T) and two more having 0.5% weight iron loads, one for the silica support (catalyst 2FS) and the last one the titanium support (catalyst 2FT). The higher BET areas were 659 and 850 m2/g for catalysts 1S and 2FS, respectively while catalysts 1T and 2FT displayed areas of 65 and 54 m2/g, respectively. Scanning and transmission electronic microscopy displayed an amorphous structure in the silica-supported materials while titanium-supported materials displayed dense materials having defined structure. X-ray diffraction confirmed the silica’s amorphous structure in 1S and 2FS catalysts and displayed the 1T and 2FT catalysts’ anatase structure. The programmed temperature reduction for the 1S and 2FS catalysts did not display reducible species, while displaying hydrogen consumption peaks related to Fe3O4 reduction to α-Fe via FexO route for 1T and 2FT catalysts. The electronic spectroscopy X-ray photo confirmed the Fe(III) specie as having 710.6 e.V binding energy for both 2FS and 2FT catalysts. Catalytic activity was carried out at atmospheric pressure in a quartz reactor, reaction mixture as CH4/O2/N2 =7.5/1/4 at 400-800°C temperature range. The reaction products were analysed by gas chromatography on Hayesep R and T columns using 5Å molecular screening. The best response for selective oxidation of methane to formaldehyde was displayed by the 2FS catalyst with 3.4% mol methane conversion at 650°C, 11.9% mol formaldehyde selectivity and 0.0211 g HCHO/Kg catalyst yield.
Mathematical models of membrane fouling in cross-flow micro-filtration
Authors: Ortíz Jerez Mónica Jimena , Vélez Pasos Carlos Antonio , Franco Mejía Edinson
Published: August 2022

The greatest difficulty arising during cross-flow micro-filtration is the formation of a cake layer on the membrane surface (also called fouling), thereby affecting system performance. Fouling has been related to permeate flux decay resulting from changes in operating variables. Many articles have been published in an attempt to explain this phenomenon but it has not yet been fully understood because it depends on specific solution/membrane interactions and differing parameters. This work was aimed at presenting an analytical review of recently published mathematical models to explain fouling. Although the reviewed models can be adjusted to any type of application, a simple “concentration polarisation” model is advisable in the particular case of tropical fruit juices for describing the insoluble solids being deposited on membrane surface.
Analysing the Diana Turbay CAMI emergency and hospitalisation processes using an Arena 10.0 simulation model for optimal human resource distribution
Authors: Pantoja Rojas Liliana Maria , Garavito Herrera Luís Antonio
Published: August 2022

This document presents a simulation model describing the current emergency and hospitalisation procedure for the Diana Turbay Immediate Medical Attention Centre (CAMI), a first level health-providing entity, being a dependency  of the state Rafael Uribe Uribe hospital (a social entity) in Bogotá (Colombia). A summary of the study was made as well as an overall record of activities being carried out in current attention in the emergency and hospitalisation area and proposals for improving conditions for attending patients and helping to a optimise the institution’s resources in the aforementioned area. The foregoing was used for contrasting waiting times, the number of people queuing and how personnel were being used, aimed at structuring the triage procedure presented by the Rafael Uribe Uribe hospital’s Public Management and Self-control office as they wanted to implement such model within the framework of CAMI’s Remodeling and Extension project. Arena 10.0 simulation software was thus used for helping to measure the impact of such decisions on an organisation before implementing them; different scenarios were thus designed for evaluating the feasibility of reducing waiting times and the number of people queuing, different alternatives being tested regarding timetables and the availability of back-up resources, thereby revealing patients’ different attention and waiting times.
Characterising a historical bridge’s bricks in Popayán (Colombia)
Authors: Galindo Díaz Jorge Alberto , Muñoz Andrés Mauricio , Caicedo  Muñoz Marisol
Published: August 2022

This article presents the procedures and results of studying the physical-mechanical and chemical-mineralogical characterisation of the bricks originally used in a masonry arch bridge; the bridge was built in the first half of the 18th century in the city of Popayán, Colombia. Core-samples were thus extracted from the bridge’s lower area and subjected to different laboratory tests. Physical-mechanical characterisation quantified values related to dry weight, suspended weight, saturated weight, porosity, apparent gravity, apparent density and maximum load values, cold compression resistance and elasticity modulus. The results revealed the bricks’ high porosity and their low resistance to compression stress. Chemical-mineralogical characterisation involved a combination of tests including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red spectroscopy (FTIR). Several minerals found led to deducting the source of the raw material, as well as verifying some brick production characteristics of the time in the said region. Tridimite, cristobalite, magnetite and calcium carbonate were some of the phases formed by the temperatures reached while firing the bricks, while potassium sulphate presence in one of the samples conveyed the nature of the construction materials’ production characteristics. Combining XRD and XPS analysis provides information about firing temperature and the new mineralogical phases appearing at the end of this process; FTIR proved functional OH and Si-O-Si group presence. These bricks’ characteristics provided valuable data for restoration purposes, formulating a new brick from raw material complying with reconstruction requirements.
Oxidising agent and catalyst chirality effect on epoxidation of R-(+)- Limonene using Jacobsen-type catalysts
Authors: Reyes Calle Juliana , Cubillos Lobo Jairo Antonio , Montes de Correa Consuelo , Villa Holguín de P. Aída Luz
Published: August 2022

The oxidising agent effect on R-(+)-Limonene epoxide diastereoselectivity using chiral and achiral Jacobsen’s type catalysts is presented. The type of oxidising agent strongly influences diastereoselectivity. Moderate diastereomeric excesses were achieved in the presence of oxidising agents prepared in situ but in the absence of catalyst (23% for DMD and 29% for O2/pivalaldehyde). Similar diastereomeric excesses were obtained with both chiral and achiral catalyst when the oxidising agents were prepared in situ; 56% and 50% excesses were obtained when using DMD for the chiral and achiral catalyst (respectively) and 38% using O2/pivalaldehyde for both catalysts. Diastereomeric excesses were not observed in the absence of catalyst when using commercial oxidising agents; the chiral catalyst presented larger diastereomeric excesses than its achiral counterpart: 65% and 38% excess using NaOCl for the chiral and achiral catalyst, respectively, and 79% and 39% using m-CPBA for the chiral and achiral catalyst, respectively. This suggests that at least one oxidant species, different from the conventionally accepted (MnV(oxo)), might be involved in this catalytic process. A modification of the traditional catalytic cycle is proposed considering the type of oxidising agent. The catalyst’s chiral centre appears to govern asymmetric induction when commercial oxidising agents are used, whereas the R-(+)-Limonene chiral centre appears to govern asymmetric induction in the presence of  
in situ-prepared oxidising agents. On the other hand, the chemical stability of Jacobsen’s catalyst improved when in situ produced DMD was used as oxidising agent.
Modelling the kinetics of thin-layer yam (dioscorea rotundata) drying
Authors: Montes Montes Everaldo Joaquín , Torres Gallo Ramiro , Andrade Pizarro Ricardo David , Pérez Sierra Omar Andrés , Marimon Escobar José Luis , Meza Herazo Isabel Inés
Published: August 2022

Thin-layer yam (varieties 9811-089 and 9811-091) drying was evaluated in a laboratory-type dish dryer at 45°C, 55°C and 70°C and 1 m/s average air speed in the Universidad de Cordoba’s Applied Engineering laboratory. The samples were 3.19 cm long, 0.5 cm thick, in 0.5x3x5 cm slices. The effects of temperature, variety and geometry on drying-time were evaluated using a completely random factorial adjustment design: temperature (45°C, 55°C and 70°C), geometry (slices and fillets) and variety (9811-089 and 9811-091). Three repetitions were made per treatment, producing a 28.15% reduction in drying time at 70°C. Drying curves were constructed from the obtained results; it was observed that drying took place during the decreasing period, proving that diffusion was the mechanism involved in Discorea rotundata drying for the studied varieties. Drying curves were adjusted to Page, diffusion, Thompson, Newton, modified Page, Henderson and Pabis mathematical models. The logarithmic model (determined by determination coefficient (R2)) estimated mean error (SE) and relative mean deviation (%P), showing that the logarithmic model better described the drying process (R2 ≥ 99.17 and SE ≤ 0.0299).
Revisión de la modificación química del almidón con ácidos orgánicos
Authors: Peñaranda Contreras Oscar Iván , Perilla Perilla Jairo Ernesto , Algecira Enciso Néstor Ariel
Published: August 2022

La obtención de un material biodegradable a partir de la reacción del almidón con ácidos orgánicos tiene gran interés debido a que conllevaría a la generación de nuevos materiales con propiedades físicas y químicas que podrán utilizarse ampliamente en las industrias de la química fina, cosmética y alimentos. Así mismo, el almidón modificado, al poseer carácter biodegradable, ayudaría a la disminución de contaminantes de residuos sólidos. Este artículo presenta una revisión de algunos estudios sobre las modificaciones de los almidones con ácidos orgánicos y las aplicaciones en los sectores de la industria química.
Web service composition: a semantic web and automated planning technique application
Authors: Guzmán Luna Jaime Alberto , Ovalle Carranza Demetrio Arturo
Published: August 2022

This article proposes applying semantic web and artificial intelligence planning techniques to a web services composition model dealing with problems of ambiguity in web service description and handling incomplete web information. The model uses an OWL-S services and implements a planning technique which handles open world semantics in its reasoning process to resolve these problems. This resulted in a web services composition system incorporating a module for interpreting OWL-S services and converting them into a planning problem in PDDL (a planning module handling incomplete information) and an execution service module concurrently interacting with the planner for executing each composition plan service.
Characterising the human-structure interaction effect of the Olympic Stadium in Cali, Colombia
Authors: Ortiz Albert Ricardo , Gómez Daniel , Thomson Peter
Published: August 2022

This paper presents the results of analysing the human-structure interaction effect of the Olympic Stadium in Cali, Colombia.  Acceleration in the southern and western grandstands due to ambient vibration, free vibration and forced vibration tests were measured during football matches and musical performances. The data was processed using the power spectrum and time-frequency distribution, thus characterising the crowd motion for each of these events. A laboratory setup consisting of a rigid single stand was tested for characterising the jumping and damping effect of a person with regard to their posture. The loads obtained from such characterisation were incorporated into a finite element model of the southern and western grandstands to calculate the structures’ structural response. A coupling effect was observed between the loads caused by the crowd and the corresponding structural response. An increase of up to 200% in the damping of the human-structure system was observed when the structure was fully occupied by a crowd. Colombian national building code provisions for the dynamic loading of structures due to crowds are discussed.
Evaluating urban runoff pollution: sediments deposited on a road surface
Authors: Zafra Mejía Carlos Alfonso , Temprano González Javier , Tejero Monzón Iñaki
Published: August 2022

The pollution caused by runoff water continues being a great problem in urban areas. Studying the behavior of sediments deposited on a road surface serves to determine the characteristics of their build-up during dry times and wash-off during rainy periods. It will also lead to establishing pollution control mechanisms associated with the sediment deposited on particular types of road surfaces. This paper presents data regarding the sediment accumulating on a road surface in the city of Torrelavega in northern Spain during a 65-day period, during which time 132 samples were collected. Two types of sediment collection samples were obtained: vacuumed dry samples (free load) and those swept up following vacuuming (fixed load). Sediment loading, particle size distribution and moisture were determined for each type of sample. The data showed that the sediment loading (gm-2) and vacuumed availability of the load which adhered most strongly to the surface (fixed load) increased with the number of dry days. Collected sediment particle size distribution tended to be finer with the increase in the number of dry days. <125 µm particle sizes presented the greatest rate of build-up during dry time and those which were <500 µm had the greatest susceptibility to being washed off during rain.
Determining surface free energy for Colombian asphalts
Authors: Álvarez Lugo Allex E. , Caro Spinel Silvia
Published: August 2022

The surface free energy (SFE) of a material is defined as being the energy required in vacuum to create a new surface unit. This property is directly related to a material’s fracture resistance and healing properties and to its capacity for creating strong bonds with other materials. The quality of the adhesion between asphalt binders and aggregates can also be assessed by computing these materials’ work of adhesion. This value can be used as an additional parameter for selecting and appropriately combining materials for hot mix asphalt as well as a component of micromechanical models for fracture and healing within these mixtures. This paper describes in detail a technique used for measuring the SFE of asphalts based on the Wilhelmy plate method and reports the first SFE measurements available for asphalts produced in the Colombian refineries of Barrancabermeja and Apiay. Corresponding results, along with the SFE for different aggregates, were used for analysing differences in the work of adhesion for different asphalt-aggregate combinations in dry conditions. Barrancabermeja asphalt produced the highest work of adhesion amongst the materials analysed here. The results also suggested that the effect of specific mineral filler on asphalt SFE is asphalt-dependent; such effect does not necessarily lead to increasing the SFE for the corresponding asphalt-mineral filler system.
Evaluating the cooking process for obtaining hard candy from araza (Eugenia stipitata) pulp
Authors: Rodríguez Sandoval Eduardo , Bastidas Garzón Patricia
Published: August 2022

This work was aimed at preparing hard candy from arazá (a fruit tree from the Amazon rainforest) using a sugar solution consisting of glucose syrup and invert sugar; this was cooked with fruit pulp to concentrate it. Temperature, time, soluble solids and viscosity were measured when cooking the mixture. Heat transfer was studied in an agitated steam jacketed kettle using the experimental data. The best arazá hard candy formulation consisted of 15% fruit pulp, 2% pectin regarding the amount of pulp and 85% sugar solution (glucose syrup and invert sugar mixed 1:1 (w/w)). The experimental data gave 266 W/m2ºC average overall heat transfer coefficient whereas theoretical data gave a 421.8 W/m2ºC overall heat transfer coefficient. Heat transfer speed was 3,140 W.
Stator winding short-circuit fault detection in a permanent magnet synchronous motor (PMSM) using negative sequence current in time domain
Authors: Quiroga Jabid E.
Published: August 2022

A negative sequence analysis in time domain was applied to fault detection of permanent magnet synchronous motors (PMSM). The fundamental components of the motor terminal currents were obtained using a Notch filter, based on which the negative sequence components in time domain were then calculated; the negative sequence current constituted the stator winding short-circuit fault indicator. The negative sequence current also provided a qualitative evaluation regarding the severity of the fault. The proposed method promptly (< 22 ms) and reliably determined the stator winding short for different levels of severity in faults around and greater than 6.25% of the shorted phase. Experimental studies confirmed the proportional relationship between fault indicator and the level of severity. Using negative sequence current in time domain reduced computational cost and detection time compared to that in frequency domain. The proposed method could be extended to detect the shorted phase to improve monitoring. The method was validated online using a PMSM experimental setup with dSPACE and Matlab/Simulink environment.
Starting-up and operating a full-scale activated sludge system for slaughterhouse wastewater
Authors: Pabón Sandra Liliana , Suárez Gélvez John Hermógenes
Published: August 2022

This research was conducted at the Frigofrontera wastewater plant which has screening, de-sanding, a grease trap and sedimentation as its primary treatment system, an activated sludge recirculation reactor for secondary treatment and a descending bed filter for tertiary treatment. Average treated flow is 1.38 L/s; the activated sludge reactor has a 144 m3 volume and 2-day cell retention time. Reactor oxygen levels are guaranteed by injecting air using high-efficiency equipment. Basic wastewater concentration parameters are: 5,242.13 mg / L BOD5; 9,039.75 mg / L COD and 2,972.69 mg / L SS. The treatment plant was started up during February 2006 and has been in constant operation since then. It has achieved 89.73% five-day biological oxygen demand (BOD5), 89.03% chemical oxygen demand (COD) and 94.09% soluble solid (SS) load removal efficiency. The sludge produced by the process is treated by screening where the solids are separated from wastewater. The liquid is returned to the sedimenters and solids are composted.
The streamline upwind Petrov-Galerkin stabilising method for the numerical solution of highly advective problems
Authors: Galeano Urueña Carlos Humberto , Mantilla González Juan Miguel , Garzón Alvarado Diego Alexander
Published: August 2022

This article describes the streamline upwind Petrov-Galerkin (SUPG) method as being a stabilisation technique for resolving the diffusion-advection-reaction equation by finite elements. The first part of this article has a short analysis of the importance of this type of differential equation in modelling physical phenomena in multiple fields. A one-dimensional description of the SUPG method is then given to extend this basis to two and three dimensions. The outcome of a strongly advective and a high numerical complexity experiment is presented. The results show how the version of the implemented SUPG technique allowed stabilised approaches in space, even for high Peclet numbers. Additional graphs of the numerical experiments presented here can be downloaded from www.gnum.unal.edu.co.
Entropy production and Newton's cooling law
Authors: Barragán Daniel
Published: August 2022

The thermodynamic theory of irreversible processes was applied to studying heat exchange described by Newton's cooling law. It is shown that the steady states described by Newton's law are not states having minimum entropy production; it is then proved that Newton's law is not a consequence of a linear relationship between fluxes and thermodynamic forces. Systems are often constrained and heat exchange can be optimised if entropy production is minimised according to the second law.
Implementing a decision support system (DSS) in e-business
Authors: Ruiz G. Alexandra , Hernández R Leonardo A. , Giraldo O. William J.
Published: August 2022

Decision support systems (DSS) and e-business (EB) have emerged as separate areas. However, currently, and for some years now, DSS and EB have become merged to provide customers with greater benefits and added value. There are different types of DSS and different categories and business models for EB; one area's applicability to the other thus expands the possible combinations which can arise from such different categories. Some representative examples would include auction sites which, through applying intelligent agents, can learn about which products to offer or when and where to sell them; DSS allow a company's information avilable in web portals for customers and employees to be accessed in a controlled way and decisions thus made; virtual stores may be positively affected by data mining and data warehousing being applied; complex algorithms could be used in customer relationship management for predicting and analysing "what would happen if" to identify revenue opportunities in competitive markets; and a wide range of other applications where imagination is the limit. Research into DSS / BE must be ongoing due to the constant emergence of new business models and DSS subsystems. Applications can be varied and provide bi-directional support for each one. New interaction mechanisms and efforts to satisfy customers are also the focus of inspiration for new applications for DSS systems in EB.
Biological and intelligent manufacturing: human life-skills applied to technological development
Authors: Jiménez Hernández Claudia Nelcy , Castellanos Domínguez Óscar Fernando , Montoya Restrepo Luz Alexandra
Published: August 2022

Highly competitive settings, characterised by development being promoting by the predominance of knowledge, means that mul- tidisciplinary approaches must be adopted for dealing with specific problems. Indeed, techniques and tools have been created by imitating human beings’ behaviour and applying them to productive and technological contexts to increase efficiency and enable a quick response. This paper deals with this topic and presents the results of scientometric- and technological surveillance-based research for revealing life sciences’ impact on technological development and its management. It was found that such impact has been mainly reflected in producing concepts and applications for topics such as intelligent manufacturing, biological manu- facturing systems and holonic and bionic manufacturing, thereby providing manufacturing and information management with hu- man attributes such as adaptation, self-learning, flexibility and the ability to evolve. It may thus be concluded that technological factor management has been strengthened, based on fields such as biology, thereby leading to direct outcomes regarding pro- duction.
The processes involved in a management model for university patents
Authors: López Gómez María del  Socorro , Schmal Simón Rodolfo , Cabrales Gómez Fernando , García Tobón Carolina
Published: August 2022

Current tendencies in strengthening intellectual property rights and the emergence of new scientific–technological fields (such as nanotechnologies, biotechnology, telematics and software development) have forced universities to acquire sufficient knowledge aimed at protecting their research results and fulfilling a leadership role within their regional settings so that they may generate competitive innovation strategies in alliance with other social agents. However, universities must promote ethical values, respectting and defending their countries' ecological and cultural heritage when intellectual property rights are being promoted. A model for managing universities' industrial property rights is thus proposed here; it is centred on patents so as to improve strategies contributing towards Latin-American universities' scientific and technological development and thereby contribute towards their countries' development. The model is one of the relevant results derived from the theoretical framework for research carried out by the team from 2003-2007 and from the empirical study carried out in two phases. The first phase consisted of a survey whose objective was to detect critical aspects regarding managing patents and licenses for universities in Colombia, Chile and Spain. The second empirical phase consisted of holding in-depth interviews with those managing the patents for the universities having the best performance in the three aforementioned countries.
Hermenêutica filosófica e teoria crítica
Authors: Sobrinho Alexandre Machado Marques de Souza
Published: August 2022

Este trabalho busca discutir as divergências e as convergências entre a hermenêutica filosófica de Gadamer e a teoria crítica de Habermas. Nesse esforço, traçou-se um breve itinerário teórico-filosófico sobre a compreensão da realidade, ora nos termos da ação comunicativa habermasiana, ora a partir da reflexão autocompreensiva da existência gadameriana. Quais são os limites identificados por Habermas acerca da hermenêutica de Gadamer? Que críticas são elaboradas por Gadamer em relação à razão comunicativa de Habermas? É possível observar alguma unidade entre as duas abordagens teóricas ou elas são apenas diametralmente opostas? Conclui-se que a transformação almejada por Habermas não pretende anular totalmente o conhecimento tradicional conservado pelo pensamento gadameriano, assim como o conhecimento tradicional de Gadamer não descarta totalmente as possibilidades de mudança defendidas pelo viés emancipatório da teoria habermasiana.
A concepção onírica em Schopenhauer
Authors: Junior Antonio Alves Pereira
Published: August 2022

No início do século XX Sigmund Freud revolucionou a história do conhecimento humano ao conceber e caracterizar o inconsciente e sistematizar engenhosamente a psique humana. Para tal empreendimento, um dos principais instrumentos utilizado por este médico-pesquisador e fundador da psicanálise foram as análises dos sonhos, sendo essa uma das vias para compreensão e acesso do inconsciente para fins de encontrar causas patológicas e distúrbios em geral. A lista de convergências entre os pensamentos de Freud e Schopenhauer já é conhecida principalmente pelos conceitos de pulsão, vontade, sexualidade e loucura, no entanto, neste texto, tive por intenção investigar exclusivamente a concepção onírica de Schopenhauer com o objetivo de responder em até que ponto os sonhos podem estar ou não submetidos ao princípio de razão suficiente – que rege o mundo como representação no tempo, espaço e causalidade.
Estrategias didácticas en la enseñanza- aprendizaje de la lectoescritura emergente, en la pandemia del COVID-19
Authors: Quemé Oroxom Heydi Johanna
Published: August 2022

La lectoescritura emergente (LEE) es la etapa precursora donde se espera que la niñez adquiera destrezas y habilidades para aproximarse a leer y escribir, este proceso es determinante para el éxito de la escolaridad. El objetivo de este artículo es presentar los hallazgos de la investigación que identificó las similitudes y diferencias de las estrategias didácticas en cuanto a las prácticas y las adaptaciones curriculares en los procesos de enseñanza-aprendizaje de la LEE en modalidad remota durante la pandemia del COVID-19. La investigación se realizó en el primer trimestre del año 2021, mediante una metodología cualitativa de alcance descriptivo, con estudio de casos que correspondió a dos establecimientos educativos privados y uno público del occidente de Guatemala. Se realizó una revisión documental de las planificaciones del área de Comunicación y Lenguaje L1, la observación de clases en plataformas virtuales y entrevistas semiestructuradas a docentes, directores y madres de familia. Se trianguló la información y reveló hallazgos: 1) en la práctica de las estrategias didácticas lo que se encuentra son técnicas didácticas que fueron determinadas desde el trabajo en modalidad remota, 2) las adaptaciones curriculares que las docentes realizaron en modalidad remota y 3) los retos a los que se enfrentó la comunidad educativa en el proceso de enseñanza-aprendizaje por la pandemia. Se concluye con la necesidad de trabajar estrategias para la modalidad remota que permitan alcanzar las competencias propuestas para el desarrollo de todos los elementos clave de la LEE.
Proposed lump-sum formulas for long-term prestress losses
Authors: Al-Omaishi Nabil
Published: August 2022

The current American Association of State Highway and Transportation Officials’ AASHTO LRFD Bridge Design Specifications’ approximate formula for estimating long-term prestress losses is the outcome of the research work presented in National Cooperative Highway Research Program report 496. It is produced by simplifying the detailed method and taking into account the variability of concrete properties and the interaction between the precast concrete girder and cast-in-place deck. This paper presents two detailed parametric studies based on the average con­ditions for the design and construction of commonly used bridge girders. Three spans and, consequently, three levels of prestressing for each section have been considered. The first study establishes the creep multiplier Nc, whereas the second study evaluates the shrinkage multiplier Ns. Both multipliers are used in the lump-sum formulas for estimat­ing long-term prestress losses for different bridge girders. The multipliers produced by these studies are compared with that of the current AASHTO LRFD specifications’ approximate method, and new lump-sum formulas for long-term prestress losses are proposed.