bluuebunny/crossref_metadata_2025 huggingface dataset:
High-School Computer Science – Its Effect on the Choice of Higher Education
Authors: Armoni Michal , Gal-Ezer Judith
Published: August 2022

In a previous publication we examined the connections between high-school computer science (CS) and computing higher education. The results were promising—students who were exposed to computing in high school were more likely to take one of the computing disciplines. However, these correlations were not necessarily causal. Possibly those students who took CS courses, and especially high-level CS courses in high school, were already a priori inclined to pursue computing education. This uncertainty led us to pursue the current research. We aimed at finding those factors that induced students to choose CS at high school and later at higher-education institutes. We present quantitative findings obtained from analyzing freshmen computing students' responses to a designated questionnaire. The findings show that not only did high-school CS studies have a major impact on students’ choice whether to study computing in higher education—it may have also improved their view of the discipline.
Reducción de la luxación glenohumeral anteroinferior aguda en el sistema de salud de la Argentina. Perspectiva nacional
Authors: Argüelles Santiago , Anchundia Joffre , Chele Alex , Holc Fernando , David José
Published: August 2022

Objetivo: Conocer los métodos utilizados para el tratamiento inicial del primer episodio de luxación glenohumeral anteroinferior aguda y comparar las conductas entre los diferentes niveles de especialización. Nuestra hipótesis es que los métodos utilizados en la Argentina presentan una gran variabilidad.
Materiales y Métodos: Se realizó una encuesta mediante formularios de Google, que se difundió a través del Comité de Morbimortalidad de la Asociación Argentina de Ortopedia y Traumatología y la Asociación Argentina de Cirugía de Hombro y Codo. El cuestionario consta de 13 preguntas con respuesta de opción múltiple que incluyen: grado de especialización, ámbito laboral, maniobras utilizadas, empleo de anestesia, complicaciones, posición y tiempo de inmovilización.
Resultados: Se obtuvieron 429 respuestas completas. El 52,2% utiliza la maniobra de Kocher como primera elección, seguida del método hipocrático (15,9%). El 72% no utiliza anestesia inicialmente para la reducción; se halló una diferencia estadísticamente significativa entre el uso de anestesia y los diferentes niveles de especialización (p = 0,046). De los 120 médicos que sí la emplean, el 85,8% recurre a la anestesia general o la sedación. El 74,8% inmoviliza al paciente en aducción y rotación interna. El 13,8% de los participantes refiere haber tenido alguna complicación relacionada con la reducción.
Conclusiones: Existe una gran variabilidad en los métodos utilizados para la reducción de un primer episodio de luxación glenohumeral anteroinferior en los servicios de emergencia de la Argentina. Consideramos oportuno replantear el uso de la anestesia, y proponer la anestesia intrarticular como primera opción.
Eficacia y adaptabilidad de uso del dispositivo Shoulder Pacemaker® durante la fase de fortalecimiento en la rehabilitación de hombro. Estudio preliminar
Authors: Torres-Dávila Byron , Chaves-Lara Carlos Andrés
Published: August 2022

La patología de hombro es una de las causas más comunes de atención en salas de Ortopedia, y puede deberse a múltiples entidades, como inestabilidad, lesiones del manguito rotador, artrosis, capsulitis adhesiva, que pueden provocar un sinnúmero de signos o síntomas, y requerirán un manejo integral. Uno de los pilares fundamentales en el manejo de la patología de hombro es la fisioterapia. El avance tecnológico ha permitido la incorporación de dispositivos que nos ayudan a mejorar el proceso de fisioterapia. En este estudio, compartimos nuestra experiencia con el uso del Shoulder Pacemaker®, un dispositivo diseñado para mejorar el balance muscular en pacientes con patología de hombro.
¿Somos los cirujanos argentinos de hombro y codo los peor tratados de Iberoamérica?
Authors: Moya Daniel , Gómez Diego , Vila Marcelo , Alfano Federico
Published: August 2022

Un nivel de satisfacción laboral adecuado de los miembros del equipo de salud es esencial para garantizar una buena prestación de servicios, generar compromiso personal, estimular el deseo de actualización y fomentar la retención dentro del sistema. No hemos encontrado ninguna publicación que aborde específicamente este tema en el ámbito de la Ortopedia y Traumatología en nuestro medio. El objetivo de este estudio es conocer cómo perciben los especialistas que pertenecen a la Asociación Argentina de Cirugía de Hombro y Codo sus condiciones de trabajo, cuál es su remuneración y su grado de satisfacción y compararlos con equivalentes de otros países iberoamericanos. Los resultados de la encuesta mostraron niveles promedio de satisfacción bajos en los profesionales argentinos encuestados. Existen diferencias estadísticamente significativas con profesionales de otros países de Iberoamérica tanto en lo relativo a la remuneración como en los índices de bienestar. Si no se producen profundos cambios en el sistema de atención, la remuneración y las condiciones de trabajo, tarde o temprano aparecerán consecuencias que afectarán no solo a los profesionales, sino también a los pacientes y al sistema en general.
Roturas “irreparables” del manguito rotador: trucos y consejos para conseguir una reparación artroscópica
Authors: Sánchez-Losilla Cristina , Ferré-Aniorte Alfred , Ramírez-Haua Jorge , Álvarez-Díaz Pedro , Cugat Ramón , Alentorn-Geli Eduard
Published: August 2022

Las roturas irreparables del manguito rotador son lesiones graves que pueden conllevar consecuencias drásticas en la calidad de vida de los pacientes. Pese a que su reparación es compleja y la tasa de re-rotura es alta, el intento de reparación se justifica por la ausencia de alternativas poco agresivas o paliativas. Cuando no se consigue una reparación, la alternativa es la transferencia tendinosa, la reconstrucción capsular superior o incluso la prótesis invertida de hombro. Por tanto, en muchos casos de cirugía primaria, se debe intentar la reparación artroscópica con el fin de “salvar” el manguito rotador gravemente lesionado. El objetivo de este artículo es resumir algunas de las técnicas artroscópicas para conseguir una reparación de roturas “irreparables” del manguito rotador.
Ontología social y justicia. Buscando una base amplia para la justicia global
Authors: Blanco Brotons Francisco
Published: August 2022

Una de las principales aportaciones de Rawls fue su concepción de la justicia como algo predicable de la estructura social. La justicia, según él, es la primera virtud de la estructura básica. La tesis que se defiende en este artículo es que, si queremos una teoría de la justicia aplicable a nuestro mundo en globalización, tenemos que desarrollar una concepción de la estructura social diferente a la contemplada por Rawls. Con este fin, se expondrán las carencias de la ontología social mantenida por Rawls para alcanzar una justicia adecuada a nuestro mundo en globalización y se propondrá, siguiendo a Nancy Fraser e Iris Marion Young, una alternativa más adecuada a la realidad que vivimos hoy.
Fatalismo
Authors: Browne Santander José Ignacio
Published: August 2022

El artículo que sigue fue publicado originalmente con el título “Fatalism” en The Philosophical Review, Vol. 71, No.1 (1962): pp. 56–66. El artículo original es de dominio público. Agradezco a Nicolás Alarcón y Paul Sargent que leyeron una versión previa de esta traducción que permitió corregir errores. Los que quedan son de mi responsabilidad.
Los fragmentos del tratado Sobre los acertijos de Clearco de Solos
Authors: Gardella Mariana
Published: August 2022

En este trabajo, presento una traducción del griego antiguo al castellano de los fragmentos del tratado Sobre los acertijos de Clearco de Solos. En esta obra, encontramos una definición de “acertijo”, un criterio de clasificación y numerosos ejemplos. La traducción está acompañada de una introducción en la que presento algunas observaciones sobre la transmisión del tratado Sobre los acertijos y analizo el concepto de “acertijo”, teniendo en cuenta la definición y los ejemplos que propone Clearco.
A la memoria de Jean-Luc Nancy
Authors: Acosta López María del Rosario
Published: August 2022

El pasado 23 de agosto murió el filósofo francés Jean-Luc Nancy, quien deja tras de sí no solo una obra extensa, sino toda una vida dedicada al pensamiento filosófico que ha sido determinante para el curso de la filosofía contemporánea. Jean-Luc nos deja sus escritos, así como la memoria de su generosidad y pasión por el pensar en común.
Murmullo
Authors: Acosta López María del Rosario , Nancy Jean-Luc , Pérez Moreno Juan Diego
Published: August 2022

En esta conversación, María del Rosario Acosta y Jean-Luc Nancy reflexionan sobre los distintos registros de la palabra "murmullo" y la relación que puede establecerse entre cada uno de ellos y la pregunta por la crítica política y de lo político en el pensamiento de Nancy. El aspecto sonoro del murmullo permite acercarse, por un lado, a una reflexión sobre la circulación del sentido en términos de resonancia. Conduce también a la pregunta por la singularidad de la experiencia de la escucha en la constitución de ser-en-común, y por el papel del testimonio - y la desaparición de espacios para su escucha - en medio de las múltiples violencias que afectan nuestro presente histórico. Nancy revisa algunas de sus posturas anteriores frente a estas preguntas, profundiza en otras, y trae a colación temas nuevos que no se encuentran desarrollados en otros de sus escritos.
Normas regulativas y normas constitutivas. Una revisión metateórica de la distinción
Authors: Villegas Aleksov Diego
Published: August 2022

El objeto de este trabajo es, por un lado, recopilar los principales estudios teóricos y filosóficos que han servido para diferenciar entre reglas regulativas y reglas constitutivas, y por otro, realizar una revisión de dichas propuestas para efectos de cuestionar la posibilidad de una distinción tajante entre ambos tipos de reglas. La primera parte del texto corresponde a una exposición de los postulados de los autores enunciados. En segundo lugar, se formulan cuestionamientos a los criterios que se advierten en el apartado precedente. Finalmente, se expone la viabilidad de una distinción concluyente entre ambos tipos de reglas.
Optimising a shaft’s geometry by applying genetic algorithms
Authors: Guzmán María Alejandra , Delgado Alberto
Published: August 2022

Many engineering design tasks involve optimizing several conflicting goals; these types of problem are known as Multiobjective Optimization Problems (MOPs). Evolutionary techniques have proved to be an effective tool for finding solutions to these MOPs during the last decade. Variations on the basic genetic algorithm have been particularly proposed by different researchers for finding rapid optimal solutions to MOPs. The NSGA (Non-dominated Sorting Genetic Algorithm) has been implemented in this paper for finding an optimal design for a shaft subjected to cyclic loads, the conflicting goals being minimum weight and minimum lateral deflection.
Surveillance as an innovative tool for furthering technological development as applied to the plastic packaging sector
Authors: Vargas Freddy Abel , Castellanos Domínguez Óscar Fernando
Published: August 2022

The demand for production process efficiency and quality has made it necessary to resort to new tools for development and technological innovation. Surveillance of the environment has thus been identified as being a priority, paying special attention to technology which (by its changing nature) is a key factor in competitiveness. Surveillance is a routine activity in developed countries’ organizations; however, few suitable studies have been carried out in Colombia and few instruments produced for applying it to existing sectors of the economy. The present article attempts to define a methodology for technological awareness (based on transforming the information contained in databases) by means of constructing technological maps contributing useful knowledge to production processes.
This methodology has been applied to the flexible plastic packaging sector. The main trends in this industry’s technological development were identified allowing strategies to be proposed for incorporating these advances and tendencies in national companies and research groups involved in flexible plastic packaging technological development and innovation. Technological mapping’s possibilities as an important instrument for producing technological development in a given sector are then analyzed as are their possibilities for being used in other production processes.
GAC. A methodology for cresting dynamic websites
Authors: Charalambos Jean Pierre , Martínez José Andrés
Published: August 2022

This paper presents a novel website design methodology. The methodology is suitable for developing medium-sized websites and web applications as it is inspired by brainstorming and using mind maps. The proposed approach employs two well-defined roles: the interviewer and interviewee. The former could be identified with a web designer whilst the latter is more related to someone handling informatics. Practical experience has shown that a series of brainstorming sessions naturally leads to the system underlying the data-base structure.
Designing and constructing a controlled prototype for steel gaseous carburisation using alcohols
Authors: Obando B Johnny F , Castro P Álvaro , Trujillo Carlos Alexander
Published: August 2022

This article deals with designing, constructing and testing a laboratory scale apparatus for heat treatment with controlled atmosphere. The equipment was used for studying steel carburisation with alcohols. The equipment has an area for the controlled production of a gas atmosphere composed by up to 3 gases and 2 volatile liquids, an inert and hermetic isothermal reaction area and a gas analysis area which retains solids and condensable liquids. The equipment was provided with pressure and carbon dioxide concentration sensors. Eight experiments were carried out with methanol, ethanol, n-propanol, isopropanol and tertbutanol as carbon source. The results showed that methanol caused carburisation but layer depth was small and produced a low quantity of soot, ethanol caused decarburisation and formed large quantities of soot, n-propanol, isopropanol and the tertbutanol provided good carbon potential and layers having good depth with good soot and tar production. Soot and tar production followed this order: n-propanol < tertbutanol < isopropanol.
Economic feasibility study regarding the applicability of ultrasonic inspection of the Cuban sugar industry’s sugarcane mill shafts
Authors: Arzola de la Peña Nelson
Published: August 2022

This article evaluates the economic feasibility of carrying out ultrasonic inspection of sugar-mill shafts. Four alternatives are considered, including the most frequently encountered scenarios. How and when inspections are carried out is analysed, periods between inspections being established by a fatigue-crack growth propagation approach. The lifecycle cost approach was applied for economic evaluation. Operation, maintenance and energy consumption costs were thus taken into consideration. The conclusion was drawn that it is highly advisable to use high performance ultrasonic inspection. Introducing ultrasonic inspection (according to the period of time obtained by fracture mechanics model) could lead to a saving of half a million dollars per year for the Cuban sugarcane industry in the current conditions.
Sorbent biomaterials for cleaning up hydrocarbon spills on soil and bodies of water
Authors: Ortíz González Diana Paola , Fonseca Fabio Andrade , Rodríguez Niño Gerardo , Montenegro Ruiz Luis Carlos
Published: August 2022

This study was aimed at identifying and evaluating natural organic materials which could be used as sorbents in clean-up operations following hydrocarbons spills on both soils and bodies of water. The sorption capacity of three materials (sugarcane fiber, coco fiber and water Eichornia crassipies was evaluated with three hydrocarbons (35°, 30° and 25°API) and two types of water (distilled and artificial marine water) adopting the ASTM F-726 standard and following the methodology suggested in the “Oil spill sorbents: testing protocol and certification listing programme” Canadian protocol. It was found that the three materials being evaluated had a sorption capacity equal to or greater than that of the commercial material to which they were compared. It was observed that sorption capacity results depended on some variables such as hydrocarbon viscosity, granulometry (particle size in Tyler sieve) and the structure of the material. Sugarcane fiber sorption in water showed the greatest hydrophobicity, different to Eichornia crassipies which is extremely hydrophilic. The materials’ sorption kinetics were determined and modelled with the three hydrocarbons (35°, 30° and 25°API). It was found that the materials became saturated in less than a minute, leading to a rapid alternative for cleaning-up and controlling hydrocarbon spills. Materials were also thermally treated for improving their hydrophobicity and behavior during spills on bodies of water. Sugarcane fiber was the material which presented the best results with the thermal treatment, followed by water Eichornia crassipies. Coco fiber did not present any significant change in its hydrophobicity.
A study of butyl acetate synthesis. 4. reaction kinetics
Authors: Orjuela Londoño Álvaro , Leiva Lenis Fernando , Boyacá Mendivelso Luis Alejandro , Rodríguez Niño Gerardo , Carballo Suárez Luis María
Published: August 2022

This work was aimed at studying liquid-phase acetic acid and butyl alcohol esterification reaction (Patm =0.76 Bar), using an ion exchange resin (Lewatit K-2431) as catalyst. The effect of the absence of internal and external mass transport on catalyst particles was established in the research conditions used here. A set of assays to determine the effect of catalyst load (0.5%, 1%, 2% w/w) temperature (73°C, 80°C, 87°C) and molar ratio (1:2, 1:1, 2:1 acid/ alcohol) on reaction rate was carried out and both LHHW and pseudo-homogeneous kinetic expressions were obtained, these being in good agreement with the experimental data.
Perspectives in developing industrial enzymes by using technological intelligence
Authors: Castellanos Domínguez Óscar Fernando , Ramírez Martínez Diana Cristina , Montañez Víctor Mauricio
Published: August 2022

Developing emergent technologies implies an ongoing challenge involving using new technological management tools. Enzyme engineering and its respective technology (within the context of biotechnology) is one of the areas of knowledge from which great expectations are constantly arising, such as providing competitive advantage in emergent economies like that of Colombia. However, several decades of research in this field have still not led to important results in terms of enzyme production and their application in industrial processes. This article proposes applying the components of a technological intelligence system to developing enzyme technology. Initial emphasis is placed on scientometrics, using exercises for mapping patents, technological monitoring and evaluating Colombian projects forming part of Colciencias’ ScienTI network, carried out for the enzymes being used in both the food industry for obtaining hydrolysed products and in the textile industry. An example of Delphi study is documented within the context of industrial enzymes’ future within biotechnology in general. The learning which can arise from analysing a sector leader is stressed by using organisational benchmarking. The basis of a technological intelligence system is then discussed in terms of how it can provide productive and competitive strategies aimed at applying industrial enzymes.
Designing educational software for analysing pressurised hydraulic systems in civil engineering
Authors: Pallares Muñoz Myriam Rocío , Rodríguez Calderón Wilson
Published: August 2022

New information technologies have opened up a world of inexhaustible possibilities in teaching. Using such technologies in technical teaching has become indispensable due to the nature of current resources in industrial design and production. This work consists of preparing didactic material (educational software) aimed at teaching fluid mechanics, particularly analysing tube, tank and pumping systems, initially aimed at civil engineering students from the Universidad Santo Tomás in Bogotá. Such materials have been successfully developed and used in their formal programs by several universities around the world during the last few years. The didactic software mentioned in this work was constructed using Visual Basic programming language. This has resulted in a very useful educational tool, leading to effective teacher-student communication which is suitable for both the classroom and students’ personal work (Angel y Bautista, 2001; Aguilar, 2002).
Networking automation of ECI’s G-204 electronic engineering laboratory
Authors: Paz Penagos Hernán , Castellanos Tache Germán Darío , Alarcón Ballesteros Ronald Ferney , Weiss Velandia Viviana Lucia , Laverde Cañón Ángela Roció , Rodríguez Calderón Juan Carlos , Rincón Fosca Leonel Andrés
Published: August 2022

Increased use (by students and teachers) of the “Escuela Colombiana de Ingeniería Julio Garavito” Electronic Engineering laboratories during the last year has congested access to these laboratories; the School’s Electronic Engineering (Ecitrónica) programme’s applied Electronic studies’ center research group thus proposed, designed and developed a research project taking advantage of G building’s electrical distribution to offer access facilities, laboratory equipment control, energy saving and improved service quality. The G-204 laboratory’s network system will have an access control subsystem with client-main computer architecture. The latter consists of a user, schedule, group and work-bank database; the user is connected from any computer (client) to the main computer through Internet to reserve his/her turn at laboratory practice by selecting the schedule, group, work-bank, network type required (1Φ or 3 Φ) and registering co-workers. Access to the G-204 laboratory on the day and time of practice is made by means of an intelligent card reader. Information of public interest produced and controlled by the main computer is displayed on three LCD screens located on one of G building’s second floor walls, as is an electronic clock. The G-204 laboratory temperature and time are continually updated. Work-banks are enabled or disabled by the main computer; the work banks are provided with power (beginning of practice) or disconnected (end of practice or due to eventualities) to protect the equipment, save energy, facilitate monitors and supervise the logistics of the state of the equipment at the end of each practice. The research group was organised into Transmission Line and Applications sub-groups. Power Line Communications PLC technology was used for to exploring digital modulation alternatives, coding and detecting errors, coupling, data transmission protocols and new applications, all based on channel estimation (networking) as the means of transmission.
Subcritical hydrothermal conversion of organic wastes and biomass. Reaction pathways
Authors: Castro Vega Alejandro Amadeus , Rodríguez Varela Luis Ignacio , Díaz Velásquez José de Jesús
Published: August 2022

Hydrothermal conversion is a procedure which emulates organic matter’s natural conversion into bio-crude having physical and chemical properties analogous to petroleum. The artificial transformation of biomass requires previous knowledge of the main reaction routes and product availability. The main component of biomass (depolymerisation by hydrolysis) is presented in hydrothermal cellulose conversion, producing oligosaccharides which exhibit dehydration and retro-aldol condensation reactions for transforming into furfurals and carboxylic acids. Other biomass components (such as lignin, proteins, and fat esters) present both hydrolysis and pyrolysis reaction routes. As long as biomass mainly contains carbohydrates, subcritical hydrothermal conversion products and their wastes will be fundamentally analogous to those displaying cellulose. These substances have added value by far surpassing raw material’s acquisition cost. When the main hydrothermal conversion products’ O/C, H/C molar ratios as reported in literature are plotted, an evolutionary trajectory for conversion products appears to be closely or even overlapped with fossil fuels’ geological evolution.
Neural network fault diagnosis. Part II: flow recognition
Authors: Tarifa Enrique Eduardo , Martínez Sergio Luis
Published: August 2022

The diagnostic system introduced in Part I is modified in this work for supervising complex processes when faults present themselves. As in Part I, it is supposed that when a fault affects a process, then each variable evolves following a trajectory. However, this time the aforementioned trajectory is not unique but belongs to a set of infinite possible trajectories named flow. Each fault in a particular flow is associated with each variable. Faults affecting a process can then be diagnosed by recognising which flow the trajectory being observed belongs to for every variable in turn. Once flows have been identified, then the fault causing them is also identified. Theory was developed after modelling fault diagnosis as being a flow recognition problem, definitions being yielded for both structure and training method for the artificial neural networks used by the new diagnostic system. The diagnostic system performed well in tests, diagnosis being exact, having high, stable resolution in the presence of noise. The theory so developed recommends networks being scaled-up for supervising more complex processes.
Metaheuristics applied to vehicle routing. A case study. Part 3: Genetic Clustering and Tabu Routing
Authors: González Vargas Guillermo , González Aristizábal Felipe
Published: August 2022

This paper presents hybrid meta-heuristics called Genetic Clustering and Tabu Routing for solving a vehicle routing problem using two phases methodology: first clustering and then routing. The results are compared with those obtained using meta-heuristics and heuristic techniques presented in previous papers. Genetic clustering and Tabu routing average results were 23% and 9.1% better, respectively.
A review of liquid-phase catalytic hydrodechlorination
Authors: Ardila Arias Alba Nelly , Montes de Correa Consuelo
Published: August 2022

This survey was aimed at introducing the effect of light organochlorinated compound emissions on the environment, particularly on water, air, soil, biota and human beings. The characteristics and advantages of liquid phase catalytic hydrodechlorination as a technology for degrading these chlorinated compounds is also outlined and the main catalysts used in the hydrodechlorination process are described. Special emphasis is placed on palladium catalysts, their activity, the nature of active species and deactivation. The effect of several parameters is introduced, such as HCl, solvent, base addition and type of reducing agent used. The main results of kinetic studies, reactors used and the most important survey conclusions are presented.
Reduction of power line interference in electrocardiographic signals by dual Kalman filtering
Authors: Avendaño Valencia Luis David , Avendaño Luis Enrique , Ferrero José María , Castellanos Domínguez Germán
Published: August 2022

This paper presents a filter for reducing powerline interference in electrocardiographic signals (ECG), based on dual parameter and state estimation using with a Kalman filter. Two models were used to represent power-line interference and ECG signal. Both models were combined to simulate the ECG signal whose state was estimated for separating the ECG signal from the interference. The proposed algorithm was fine-tuned and compared using a set of tests relying on the QT arrhythmia database. Tuning tests were done for tracking clean ECG; these results were used for setting the algorithm’s parameters for later filtering tests. Exhaustive filtering tests were carried out on artificially corrupted database registers for given signal to noise ratios; performance curves were thus obtained, leading to comparing the proposed algorithm with other filtering methods. The proposed algorithm was compared to an recursive infinite impulse response filter (IIR) and a Kalman filter based on a simpler model. A filtering algorithm was thus obtained which is robust for changes in interference amplitude and keeps these properties for different types of ECG morphologies.
Gas transport network analysis
Authors: Eduardo Tarifa Enrique , Erdmann Eleonora , Humana Demetrio , Vicente María Soledad , Cari Luis Rodolfo , Mercado Fuentes Lorgio
Published: August 2022

Growing demand for natural gas necessarily leads to demands for increased transport network capacity.
This can be done by increasing the capacity of already installed gas pipelines and optimising operating conditions. Greater knowledge (know-how) regarding the process is thus needed and may be applied by following the procedure outlined in this work. The proposed method concerns studying a gas network by using simulation tools; it has been used for studying a transport network in Argentina. The proposed method has the following stages: 1) system analysis (identifying parameters, disturbances, manipulated variables, state variables and output variables), 2) stationary simulation, 3) dynamic simulation and 4) case studies (analysing sensitivity, stability and controllability). Once a system’s critical variables have been identified then stationary simulation allows the amount of gas and its pressure to be determined for each sink, in several scenarios. These results can be used for designing suitable operational procedure for such cases.
Dynamic simulation describes a system’s stationary state and how the state of the process evolves. Such additional information allows refining previously-designed procedures and also makes dynamic simulation an excellent tool for operator training. Two alternatives were analysed for stationary simulation: an HYSYS simulator and traditional Excel spreadsheet calculations. Predicted stationary states were similar by both methods. The sensitivity of the most relevant system variables was then studied; the HYSYS simulator was used for dynamic simulation in all cases. System sensitivity and dynamics were determined, such information being required for making improvements to network installations and operational procedures and thereby proving the procedure’s worth.
A numerical water-hammer model using Scilab
Authors: Rodríguez Calderón Wilson , Pallares Muñoz Myriam Rocío
Published: August 2022

A water hammer can produce severe consequences regarding pipe integrity; simulation thus becomes an essential requirement for ensuring proper water distribution system design and operation. This article thus tries to demonstrate the importance of numerical methods in resolving such problems. A Scilab code allowing pressure propagation to be represented using the characteristics’ method applied to a case of classic literature was thus developed for numerically simulating this phenomenon. This method uses a finite difference scheme for resolving mass and momentum equations. The article presents equations governing the problem from the numerical point of view, the phenomenon’s behavior is analysed and results obtained by the numerical approach (calculating finite differences) are compared to those obtained with Scilab and the theoretical solution.
Super-heater tube failure due to overheating when using bagasse as fuel
Authors: Coronado Marín John Jairo
Published: August 2022

A super-heater’s boiler tubes presented external longitudinal cracks. The tubes’ external surfaces presented a reddish-white layer consisting of paraffin chains: CH, functional groups: CO, NH and sulphur compounds. This brittle layer prevented heat transfer, thereby causing increased tube temperature. Creep led to failure due to long-term overheating. The steel tubes’ microstructure presented grain growth, cementite globulisation and intergranular cracks on the external surface. The foregoing observations support microstructure deterioration facilitated by the presence of unsuitable super-heater tube material when just using bagasse as fuel.
Preliminary design and economical study of a biogas production-plant using cow manure
Authors: Mantilla González Juan Miguel , Duque Daza Carlos Alberto , Galeano Urueña Carlos Humberto
Published: August 2022

This article presents considerations and results from designing a large-scale biogas production-plant using cow manure. The so designed plant capacity allowed processing the dung from 1,300 cows, producing 500 kW of electrical energy from operating a generator which works on a mixture of diesel and biogas fuel. The design included sizing the cowsheds, the manure-collecting systems, transporting the dung, the digester, the effluent tank and the biogas treatment system. An economic study was also done, concluding that project was viable and the importance of the cost of diesel evolving for determining return on investment time.
Basis for implementing a model of intelligence for strengthening the technological development of the software industry and its associated services in Colombia
Authors: Fúquene Montañez Aida Mayerly , Castellanos Domínguez Óscar Fernando , Fonseca Sandra Lorena
Published: August 2022

Interpreting technology by the entities responsible for decision-making at different levels of production systems has currently taken on great importance. Such behavior has been especially reflected in Colombia in strategic sectors producing competitive advantages for the country. The software industry and its associated services (SSA being one of them), characterised by their rapid growth and producing high added value, is based on know-how thereby providing a suitable setting for research and development. Such characteristics, linked to the current dynamics of managing information as support for suitable decision-making, have favoured formulating the basis for implementing a model of technological intelligence in the SSA industry. The integrated application of management tools is thus proposed (i.e. performance analysis, benchmarking, “prospectiva”, technological monitoring) for ensuring suitable identification, analysis and handling of relevant information. This would lead to taking better advantage of technology and facilitating organisations”’ decision-making. Know-how would be transferred to actors coordinating the sector and there would be strategic structuring, including socialisation and feedback. In the light of the above, the current state of the industry is reviewed, development perspectives up to 2015 and opportunities for strengthening the industry.
Basic security measures for IEEE 802.11 wireless networks
Authors: Sarmiento Oscar P. , Guerrero Fabio G. , Rey Argote David
Published: August 2022

This article presents a tutorial/discussion of three commonly-used IEEE 802.11 wireless network security standards:  WEP, WPA and WPA2. A detailed analysis of the RC4 algorithm supporting WEP is presented, including its vulnerabilities. The WPA and WPA2 encryption protocols’ most relevant aspects and technical characteristics are reviewed for a comparative analysis of the three standards in terms of the security they provide. Special attention has been paid to WEP encryption by using an educational simulation tool written in C++ Builder for facilitating the understanding of this protocol at academic level. Two practical cases of wireless security configurations using Cisco networking equipment are also presented: configuring and enabling WPA-Personal and WPA2-Personal (these being security options used by TKIP and AES, respectively).
Effect of ultraviolet radiation on an asphalt mixture’s mechanical and dynamic properties
Authors: Reyes Ortíz Oscar Javier , Camacho Tauta Javier Fernando
Published: August 2022

This research’s main goal was to determine UV radiation’s effects on a dense asphalt mixture’s mechanical and dynamic properties. Individual material components were characterised and optimum asphalt content was obtained using Marshall’s methodology. Dynamic modulus, rutting and fatigue tests were carried out using specimens previously subjected to UV radiation at different exposure times by using an aging chamber. It is worth stressing that greater UV exposure led to shorter mixture life cycles. The dynamic module increased between 90% and 132% and permanent deformation decreased by 57%, making it become a more fragile structure.
Topographical characteristics and evaluating water quality in watershed management
Authors: Tarlé Pissarra Teresa Cristina , Mazzer Rodrigues Flavia , Luna Arraes Christiano , Antonio Galbiatti João , Borges Maurício José
Published: August 2022

Se evaluaron características topográficas y muestras de agua en un cauce de la hacienda Gloria, município Jaboticabal, São Paulo, Brasil. Las características morfométricas del relieve y del agua fueron estudiadas en una pequeña cuenca hidrográfica, considerando zonas protegidas con bosque nativo y aquellas que presentaban uso agrícola de la tierra para ajustar la hipótesis de que el uso de ella afecta la calidad del agua y ayuda a predecir cómo se producen los cambios en este y en el local paisaje circundante. La calidad del agua fue evaluada en seis sitios y se analizaron los cambios de los parámetros físicos y químicos. Las muestras fueron recolectadas el mismo día de cada mes, durante un año, mediante un equipo de Horiba. Para determinar diferencias entre los sitios estudiados se realizó el análisis de varianza (Anova). El análisis de los datos presentó diferencias significativas de pH, conductividad eléctrica, turbidez, oxígeno disuelto y temperatura. Las características topográficas han sido influenciadas por las actividades agrícolas, impactando el medio ambiente. La escorrentía superficial es predominante en las laderas pronunciadas, sobre todo en las zonas altas de la cuenca. Los resultados indican la fragilidad de la cuenca agrícola a la exposición de contaminantes o agentes tóxicos, debido a la turbidez en el agua causada por la erosión de los suelos, la deposición de residuos agrícolas y por la escorrentía superficial.
New reliability charge incentives and structure in the Colombian electrical sector
Authors: Villareal Navarro Julio E. , Córdoba de la Rosa María Jimena
Published: August 2022

Ensuring sector reliability has always been an important issue in electrical sector policy. However, the challenge could be even greater for hydro-dependent systems (as in the Colombian system) operating in the South-American equatorial zone, since climatic shocks such as the “el niño” phenomenon usually have a very strong impact on supply, thereby leading to market disequilibrium. Such systems thus require a very specific regulatory structure to assure generation units as “backup units'' which may generate electrical energy during critical moments. This paper examines the new reliability charge developed by the Colombian Commission for Regulating Energy and Gas (CREG), its characteristics and incentive mechanisms to ensure Colombian electrical system reliability under extreme weather condition. The new system promotes sector reliability during periods of scarcity and provides a clear incentive for new investment in backup generation. However, the instrument’s design could be improved if it included an explicit penalty for those units which do not honor their firm energy commitment. The instrument could thus encourage the non-entry of units which have either low reliability levels or speculative purposes.
Developing a press for static and dynamic testing of orthopedic devices and biological tissue
Authors: Leyton Virgen Arlex , Ballén Briceño José Daniel , Moran Perafán Richard , Casanova García Fernando , Pinedo Jaramillo Carlos Rafael , García Alvarez José Jaime
Published: August 2022

This paper describes designing and constructing a test machine having an 1,800 N capacity and maximum 3 Hz frequency which will be used in static and dynamic testing of biological tissues and orthopedic devices such as external fixers. It consists of an octagonal base with 500 mm distance between faces and a crosshead which slides between two columns (useful 350 mm opening) thus allowing changing the height (maximum 600 mm) according to the size of the specimen to be tested. A ball screw actuator is mounted over the crosshead which transforms a servomotor’s rotating movement into a lineal movement (maximum 150 mm stroke). First validations indicated that the machine performed within the design parameters. This project shows that the technology required for supporting research is possible in developing countries thereby avoiding dependence on foreign companies for supporting, maintaining and updating equipment. Some conditions were also produced for the evolution of mechanical engineering in Colombia.
Roadmapping for improving cocoa postharvest management
Authors: Sánchez Vargas Adriana del Pilar , Castellanos Domínguez Óscar Fernando , Domínguez Martínez Karen Patricia
Published: August 2022

This article presents the methodology and results which led to preparing post-harvesting technological development strategies for cocoa management which emerged from identifying problems such as deficient cocoa quality and insufficient fermentation of the beans according to international market requirements as shown in the poor technological development in Colombia’s main cocoa producing areas. This situation led to using a technological management tool such as roadmapping orientated towards formulating strategies for the technological development of cocoa postharvest management. The methodological process so implemented involved experts’ ongoing participation in enriching and validating results whilst four phases were implemented: performance analysis, gap analysing, structuring roadmapping and formulating cocoa postharvest technological development strategies. The results obtained in this investigation were directed towards improving Colombian cocoa sector competitiveness in internal and external markets.
A software tool for teaching and training how to build and use a TOWS matrix
Authors: Mariño Ibáñez Amparo , Cortés Aldana Félix Antonio , Garzón Ruiz Luís Alejandro
Published: August 2022

Strategic planning is currently being used by most companies; it analyses current and expected future situations, determines company orientation and develops means or strategies for achieving their stated missions. This article is aimed at reviewing general considerations in strategic planning and presenting a computational tool designed for building a TOWS matrix for matching a company’s opportunities and threats with its weaknesses and, more especially, its strengths. The software development life cycle (SDLC) involved analysis, design, implementation and use. The literature about strategic planning and SWOT analysis was reviewed for making the analysis. The software only automates an aspect of the whole strategic planning process and can be used for improving students and staff training in SWOT analysis. This type of work seeks to motivate interdisciplinary research.
Influence of cassava genotype and composite flours’ substitution level on rheological behaviour during bread-making
Authors: Henao Osorio Sergio , Aristizábal Galvis Johanna
Published: August 2022

Given increasing dependence on imported wheat, studies have been carried out in Colombia regarding the use of composite wheat-cassava flour in bread-making. A project was carried out from 1986-1991 in which different cassava genotypes, harvest ages, substitution levels and bread acceptability were evaluated. However, these studies did not have any effect on the baking sector because a constant supply of high quality, high volume and reasonably-priced cassava flour was lacking. Based on these studies, this work was aimed at determining the influence of three industrial cassava market genotypes (CMC-40, HMC-1, MCOL-1505), using four wheat-cassava flour composite substitution levels (0%, 5%, 10%, 15%) regarding the rheological and fermentative characteristics of dough in bread-making. Farinogram, alveogram, amylogram and falling number index analysis were analysed. Specific volume and acceptability of three types of bread (common, mold and hamburger) were evaluated. It was determined that composite flours had higher fiber and reduced sugar content than the wheat flour pattern, thereby increasing water absorption and available sugar content during fermentation. Dough development time for the composite flours was half the average required for wheat flour and the tolerance index was higher; its stability became reduced due to increased substitution levels and its firmness increased due to a rise in water absorption. Falling number values came within an acceptable range (250- 400 s). The specific volume of all bread having 5% and 10% substitution was higher than that for the pattern. The best general acceptability was assigned to common and mold type bread from all varieties and substitution levels.
Synthesising highly reactive tin oxide using Tin(II)2- ethylhexanoate polynucleation as precursor
Authors: Montenegro Hernández Alejandra , Rodríguez Páez Jorge Enrique
Published: August 2022

Tin oxide is a widely used compound in technological applications, particularity as a catalyst, gas sensor and in making varistors, transparent conductors, electrocatalytic electrodes and photovoltaic cells. An ethylhexanoate tin salt, a carboxylic acid and poly esterification were used for synthesising highly reactive tin oxide in the present study. Synthesis was controlled by Fourier transform infrared (FTIR) spectroscopy and recording changes in viscosity. The tin oxide characteristics so obtained were determined using FTIR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The SnO2 dust synthesised and heat-treated at 550°C yielded high density aggregates, having greater than 50 μm particle size. This result demonstrates the high reactivity of the ceramic powders synthesised here.
Using optimisation for calibrating finite element models for adobe walls
Authors: Rodríguez Calderón Wilson , Pallares Muñoz Myriam Rocío
Published: August 2022

This paper presents a proposal for applying optimisation schemes to calibrating 3D linear and non-linear finite element models for analysing structural walls made out of adobe. The calibration was based on laboratory data and that from previous research. Simulation and calibration involves a deep study of the conceptual model of adobe’s structural behaviour, mathematical and numerical models and the interrelationship with optimisation schemes arising from minimising an objective function. This is defined in terms of design variables and is restricted by the values of state variables. Both were obtained from the finite element model developed at ANSYS. The optimisation scheme with which the model was automatically calibrated required a macro to be programmed using an APDL language package. This research was aimed at implementing nonlinear computational models for the structural analysis of walls based on experimental data; this provided a tool for assessing the behaviour of adobe walls with greater security so that decisions can be made to make structural rehabilitation feasible and efficient.
Studying chromium biosorption using arabica coffee leaves
Authors: Higuera Cobos Oscar Fabián , Florez García Luis Carlos , Arroyave Londoño Juan Felipe
Published: August 2022

This work was aimed at providing an alternative for removing heavy metals such as chromium from waste water (effluent) from the leather industry and galvanoplasty (coating with a thin layer of metal by electrochemical means), using coffee leaves as biomass. Using arabica coffee (Castle variety) leaves led to 82% chromium removal efficiency for 1,000 mg/L synthetic dissolutions in 4 pH dissolution operating conditions, 0 rpm agitation, 0.149 mm diameter biomass particle size and 0.85 g/ml biomass / dissolution volume ratio.