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The overall equipment effectiveness (OEE) is an indicator used in the management and continuous improvement of production systems, and is useful in identifying losses, thus reducing production costs. By analyzing the results of this indicator, the operation manager must make decisions to eliminate or reduce losses in the process. This study investigated the application of the OEE indicator in one production line in the pulp and paper industry. The implementation of OEE was performed in stages with a detailed analysis of the indicators that compose the OEE (quality, performance, and availability) to identify possible improvements. Thus, actions were implemented to improve the OEE quality index. This study provided important information that enabled the operation manager to diagnose and minimize the occurrence of failures and losses, which is often hidden and unknown to those involved in the production system.

En este artículo se estudia la fabricación y el comportamiento mecánico de paneles a base de papel reciclado. El objetivo principal del proyecto es producir un prototipo de panel que emplee elementos provenientes de residuos sólidos (papel periódico) y de un material conglomerante (cemento Portland blanco). El panel debe ser económico, debe tener buenas propiedades mecánicas y debe tener dimensiones comerciales para su uso en muros tabiques y en cielos falsos en la industria de la construcción. El Recipanel es un panel no estructural a base de papel reciclado. El Recipanel cumple las normas colombianas en lo relativo a los paneles de uso no estructural y presenta además unas excelentes características mecánicas.

El lodo de papel reciclado es una materia prima promisoria para la producción de etanol. En esta investigación, nosotros primero evaluamos el efecto de la concentración de etanol, la carga de sólidos y la cristalinidad de la celulosa sobre la hidrólisis enzimática de la celulosa. También se evaluó la producción de etanol con lodo de papel mediante el proceso de sacarificación y fermentación simultanea (SSF) e hidrólisis y fermentación separada (SHF) empleando la levadura Kluyveromyces marxianus ATCC 36907. El etanol presenta un efecto inhibitorio sobre la hidrólisis de la celulosa. Una concentración de etanol de 40 g/L genera una reducción del 79 % en la producción teórica de azúcares reductores. Al incrementar la concentración de sólidos se observa una reducción en la conversión de la celulosa a azúcares reductores obteniéndose un 76 % de conversión con 9 % de sólidos. Una mayor conversión y productividad en etanol fueron alcanzadas en el proceso SSF en relación al proceso SHF en 72 horas de tratamiento.

This paper presents a general model for the design to obtain the thickness and reinforcing steel areas of rectangular footings that support from 1 to “n” columns aligned on a longitudinal axis. The pressure diagram is considered linear. Some recently published papers are restricted to certain types of footings as the rectangular isolated footings, and rectangular combined footings that support two columns. The first part of this paper shows the minimum soil area that supports 1 to “n” columns aligned on a longitudinal axis. Three numerical examples are presented for design of rectangular footings subjected to an axial load and two orthogonal moments in each column that supports one, two and three columns. The main advantage of this document over other documents is: this model can be applied for one or more columns supported on a rectangular footing (unrestricted on its sides, one side restricted and two opposite sides restricted).

This paper researches the influence of zinc coating of galvanized DP600 steel (DP600G) on the nugget development and mechanical properties of dissimilar DP600 - AISI304 welded joints obtained by resistance spot welding process (RSW). The RSW evaluations consisted of determining, from the dynamic resistance curves, the different stages involved in nugget formation. The experimental results showed that the zinc coating on the DP600G steel has a significant influence on the time needed for the start of the nugget formation, two times higher than that used for non-galvanized steel. The expulsion time was delayed by 1.12 times. The presence of Zn in the DP600G/AISI304 welded joints produced smaller nugget diameters compared to the DP600/AISI304 joints for the same experimental conditions, however higher peak failure load values were obtained for the first. The causes of this unusual behavior are also analyzed in this paper.

Emerging serious games mark the beginning of a new era in video games. Emerging serious games introduce advances in distributed artificial intelligence into their design in order to guide the player’s manipulation of a specific subject in an adaptive way. In this article, we present a city simulator game, called Metropolis, which generates emergent properties. Metropolis can be used by a smart city for city planning, to make collective decisions, and for other purposes. This paper describes why Metropolis can be classified as a serious game. It also analyzes how its emergent properties can be used for managing a smart city, and especially how it promotes e-participation as an e-decision-making tool within the context of urban planning. In addition, this paper explores how Metropolis can be used to analyze a smart city’s emergent citizen and urban patterns (urban spatial distribution) based on strong e-participation.

This paper presents a method to calculate multiple voltage stability limits (VSLs), voltage stability margins (VSMs), and voltage stability curves (VSCs). A multiobjective metaheuristic algorithm was used to change real and reactive powers of loads and generators and perform contingencies of the network elements. The maximum values of real and reactive powers were selected using fast non-dominated sorting and crowding distance techniques, combined with a conventional power flow (PF), and referred to in this paper as NSPF. The results show that the method can select and assess multiple maximum real and reactive powers allowed for a bus, an area, or the power system and that it can consider changes in load, generation, and contingencies. Results were validated using the PF and continuation power flow methods. The method finds a large number of VSCs in less time than the conventional methods and estimates multiple VSLs and VSMs.

In warehouse operations management, picking is one of the most expensive and time-consuming activities; its impact can be seen in the final product delivered to clients, affecting logistic Key Performance Indicators and level of service. On the other hand, changes in picking policy and quality control are challenging to implement in a real-world context. In this paper, we used a simulation methodology to determine the best flow of products and the optimum ratio of the sample in control quality. Simulation has been shown as an useful tool for industrial engineering to determine the best flow and bottlenecks inside the warehouse. This paper found significant improvements when the proposed changes in the picking policy and quality control methods were simulated. Our research also showed that the sampling quality control brings substantial gains to the queuing time, while nonetheless maintaining the desirable quality.

This paper deals with the reactivation of three test benches of high, medium and low power electric generators for hydraulic energy conversion in the University of Carabobo Hydraulic Laboratory. The method involves three stages: i) Description of three high, medium and low power electric generators for hydraulic energy conversion, ii) Rehabilitation of three high, medium and low power electric generators for hydraulic energy conversion and iii) Evaluation of performance indexes of high, medium and low power electric generators for hydraulic conversion. The results indicate that for the low power electric generator, the position angle of the distributor blades is an experimental factor that has a significant effect on the response variables studied. With respect to the medium and high power electric generators, the most influential factor on operation and power generation is the flow supplied.

This paper presents a conceptual framework for the modelling and simulation of properties, interactions and processes of social systems based on computational templates using discrete event system specification (DEVS) formalism and OMG Systems Modelling Language (SysML) diagrams. No antecedents of this combination were found in the literature, and so this is one of the contributions of this paper. Additionally, this article explains how the principles and rules of SysML can be applied to the analysis of social systems. An example of the proposed framework based on a basic Agent_Zero model is shown. The conceptual framework was built based on a critical literature review, and included new additional elements to create a complete but simple conceptual framework. The codes for the simulations were written in Python 3.

Cable driven robots have been a widely researched topic in the last few years, this is due to the advantages that they present over conventional parallel robots. In this paper, all the areas of robotic design have been studied for a planar cable driven robot, with the objective of making it parametric, meaning that the design process and mathematical models used in this paper could be used to implement the suggested architecture to solve any specific need. Finally, using the parametric design approach, a prototype was developed and built in order to validate the design process, evaluate the robot’s precision, identify future works and improvements and foresee any trouble that was not considered during the design phase.

The majority of components used in aeronautic, automotive or transport industries are subjected to fatigue loads. Those elements should be designed considering the fatigue life. In this paper the geometrical design of a right angle bracket has been simulated by FEM, considering the type of material, the applied load and the geometry of the pieces. The geometry of the right angle bracket has been optimized using the Taguchi’s robust optimization method. As far as the authors know, there are no publications dealing with the use of the Taguchi’s robust optimization method applied to the geometric design of industrial pieces having as output variable the Findley fatigue coefficient. This paper presents a method for determining the critical design parameters to extend the product life of components subject to fatigue loading. This pioneer idea is applicable to any other design or physical or mechanical application so it can be widely used as new methodology to fatigue robust design of mechanical parts and components.

The use of information and telecommunication technologies (ICT) for the development of educational tools such as virtual laboratories has become a valuable teaching support practice in different areas of professional training. Current applications range from virtualization practices in fundamental sciences, to virtual experimentation on specific engineering topics. This paper describes the development of the Virtual Earthquake Engineering Lab (SISMILAB). This lab includes different applications with the objective of becoming an aid in the process of understanding and applying fundamental concepts related to the field of earthquake engineering. The aim of the lab is to strengthen the academic and research experiences of students both inside and outside the classroom. Students have readily used SISMILAB and given positive feedback regarding its effectiveness in conveying concepts and aiding in the visualization and interpretation of results. Finally, the paper discusses the impact of the virtual laboratory based on metrics obtained from questionnaires regarding student and faculty satisfaction.

This paper presented a study of abrasive disintegration in a 400 MPa Abrasive Water Jet (AWJ). Abrasive particle size and distribution play a major role in machining and cutting efficiency of abrasive water jets. Tested garnet abrasive, commonly used in the abrasive water jet treatment, and corundum. It is of scientific interest to observe the disintegration of these particles which have been interactive with uncommonly used abrasive materials. Time impact of abrasive grains on the workpiece is very short and not all the grain in the stream of being able to do the work of cutting, you should expect the possibility of recovering the abrasive treatment. Considerable importance is the increase in cutting capacity crushed grains due to reveal new cutting edges. Based on a feasibility study this paper will present some results on achieved cutting data and shows also wear of the used focusing tube - the main part responsible for the formation of the jet.

The transportation sector has been fundamental in Colombia and faces serious consequences in terms of traffic accidents. This paper examines the relationship between accidentability and most outstanding road infrastructure factors in ten urban stretches of Neiva in the period 2017-2018, following the inclusion and exclusion criteria of the International Road Assessment Program (IRAP) for developing countries in order to characterize the state of road infrastructure of the selected points. The results showed that the central sections of the city tend to be related to the day, time, type of vehicle and victim, attribute and direction of the road. The motorcyclist was the road actor most vulnerable to injuries and fatalities, Saturday and 8:00 am was where more crashes occurred. The road infrastructure factors contributing to accidents highlight the relevance of the environment in the city.

This paper provides insights into how to approach the assessment of scientific production efficiency using Data Envelopment Analysis (DEA). The methods employed in this paper take into account both the CCR and Assurance Region (AR) models, which are based on science, technology and innovation (STI) indicators. The sample focuses on the departments in Colombia as well as the Capital District (C.D.). The research concludes that both models calculate the efficiency of the units of analysis. Furthermore, according to the country’s STI targets, AR is susceptible to hierarchies generated within the variables.

Runoff on susceptible terrains that is not associated with adequate drainage causes soil erosion, as gullies. Gullies and drainage continue to be major issues in reclamation projects since soil erosion can be reactivated after the application of recovery measures. This paper describes a low-cost project framework for macrodrainage for a gully in Nazareno (MG, Brazil) to provide support to gully management and recovery. We used a simple methodology with the application of Geographic Information Systems (GIS) and concentrated hydrologic and hydraulic models (freely available softwares). The basin has steep slopes (8 to 20%) and the water flows mainly to the northwest, which contribute to exacerbate erosion problems. We studied the effect of environmental conditions on different simulations to elaborate a drainage system project using the free software tools. Therefore, the findings of this paper can aid gully management and recovery for this and other areas with similar issues.

A reliable electric power supply is of ever increasing importance in the Colombian electricity market. As such, the Energy and Gas Regulation Commission, (CREG for its acronym in Spanish), has contracted technical studies to be undertaken in order to assess reliability for Colombian electric utilities. This paper focuses on a new methodology to diagnose the reliability of a single distribution circuit that is to be used in Colombian electric utilities. The proposed methodology includes calculating known reliability indexes (SAIFI, SAIDI, CAIDI, etc.) as well as new reliability indexes in order to determine the incidence of causes of failure. This paper explains some of the required files´ characteristics (input and output files) in order to execute two applications associated with the previously mentioned methodology. These two applications were developed using Microsoft Excel for the Strategic Energy Business Unit at EMCALI EICE ESP, located on Santiago de Cali, Valle del Cauca, Colombia, South America. This article describes some features of these applications. The first case study presented, about the first application, is calculated based on this methodology, and results obtained are compared with those obtained using ETAP software. Finally, the second case study, regarding the second application, is calculated based on this methodology and results obtained are shown in this document.

A useful tool to support the decision-making process in power transformer management is risk assessment. There are few practical methodologies to assess a Transformer Risk Index (TRI). In addition, such proposals do not consider the latest advances in techniques for transformer health valuation, and they also have other drawbacks. This paper proposes a practical method to undertake risk analysis of power transformer fleets, which deal with the stated problem. The proposal appropriately considers the best attributes of the methods reported in literature in order to compute the two components of TRI, i.e., the failure probability factor and the consequence factor. Moreover, this paper contributes to the risk analysis issue by including risk matrices and clustering techniques to support the decision-making process. The presented method was tested on a fleet of fourteen transformers. This approach serves as a practical and reliable tool for asset management in power utilities.

The band saw blade, used on the wood log cutting, is exposed in service manufacturing to applications which can cause mechanical damages and affect the quality of the tool and the wood produced. To related applications, the shear stress is essential to the correct wood machining. the proposal of this paper was the numerically analyze the influence of the parallel shear force, applied vertically at the saw blade tooth, in response to the normal longitudinal tensions (σy) in service. A numeric model was constructed, by using of the commercial software based on the Finite Elements Method (FEM). In a first analysis, only a tensile stress was applied to the model on the upper edge of the blade, the deformation results obtained were used in the secondary analysis, with the simultaneous application of vertical point loads on the saw teeth.

The absence of specifications for the granulometry a quarry must produce causes a serious problem, making it difficult for quarries to adjust their processes to produce within the range required by clients, and for costumers, making it a difficult process to design asphalt mixes and concretes that conform to the granulometric curves established in regulations. It is essential to develop limit granulometric curves for quarries, adapted to customer requirements. In this paper, a methodology for granulometric control in the quarry is proposed, which includes the collection of process information, the preparation of control charts and the process capability analysis according to the established specifications. Moreover, an example of the development of limit granulometric curves is proposed for the quarry under study located in Argentina, in the province of Buenos Aires, which would allow to produce aggregates whose granulometry can be used in asphalt mixes CAC D19 and concrete pavements.

This paper presents the results obtained in the design, implementation and testing of a bidirectional CSI (Current source inverter) converter, which is capable of delivering and taking power from the grid to charge a 72 V battery bank. This converter is sized within a photovoltaic solar system designed for homes in the city of Tunja, based on real data to estimate the average consumption of a typical home in the "Cooservicios" sector of the city, proposing two ways of working the system, one to obtain a constant average consumption and another in which the total consumption is zero. The converter is implemented with all its components, digital and power stages, using for the control a TMS 320F28377S microcontroller from C2000 family, of Texas Instruments. The implementation meets specifications of: bidirectional operation as an inverter and as a rectifier, output power of 469 W, efficiency around 80%, highlighting the considerably high value required for the input inductance of 0.3 H that causes losses in the system.

Finishing materials play an important role in architectural design. Since ancient times, claddings made of noble materials (mainly stone) convey grandeur. Clearly, there was a technology to transform quarry stones into slabs using stone sawing machines. An example of this comes from the excavation work carried out in 1930 at the Temple of Artemis in Jerash (6th century AD). The archaeologists found a facility which was classified as a stone sawmill. The efficiency of such machines, their construction method and their resistance characteristics have not been studied as yet. This paper aims to define such parameters for the stone sawing machine located in Jerash.

This paper aims to verify the effectiveness of the pile integrity test (PIT) for evaluating the presence of anomaly in short caisson foundation elements, more specifically reinforcement exposure due to an execution problem during concreting. The foundation elements tested belong to the expansion of the structure of an electricity substation in the municipality of Itá, state of Santa Catarina, Brazil. In general, the PIT is not commonly used for caissons, due to the surface irregularities occurring along the shaft in this type of foundation. The obtained results showed that the PIT can promote assertiveness and safety when assessing the integrity of these foundation elements, as later confirmed at the site by excavating the problematic elements and performing visual inspection. Thus, the results may validate the use of the PIT as a tool for optimizing the executive control of cast-in-place foundations, even though a Brazilian technical standard on the use of the low strain integrity test for this purpose is still lacking.

This paper presents the geotechnical study and stability assessment of a Mining Waste Rock Dump (WRD) from a Limestone Mine in the city of Dom Feliciano/Rio Grande do Sul (RS), south of Brazil. A literature review is used to provide considerations on the geotechnical properties of materials and geometries adopted. These parameters were the basis for the stability evaluation performed on realistic profiles of the WRD and on a proposed expansion. The conclusions regarding stability are confirmed and supported by a quantitative Waste Dump classification methodology. The results obtained demonstrate the viability of adopting an optimized geometry, with a height of 25 meters for the first level and 15 meters for the second level. It is concluded that the methodology and sequence of steps adopted in the evaluation can be replicated for other WRDs and even serve as an indication for similar structures.

Electrokinetic phenomena controls and drives many interactions in soft matter physics. In biology, for example, many of living functions are derived from complicated electrokinetic phenomena that interrelates cells, solvents, ions, solutes and tissues. This paper defines, explores and provides a novel method towards the analysis and understanding of such problems. The new method is a generalization of the General Geometry Ewald-like Method (GGEM); it combines continuum and statistical mechanics through a Green’s function formalism for the long-range interactions. In this way, the separation of time and length scales, commonly encountered in soft matter fluids, is avoided. The fundamental equations behind electrokinetic problems are exposed and the paper finishes with a description of the novel Nernst-Planck-GGEM approach.

This paper presents an algorithm for the optimization of the design of reinforced concrete (RC) road bridges, taking into account the current conditions in Cuba. The use of RC is chosen over the common solutions due to the current high economic cost of prestressing steel. The optimization problem is formulated to find the minimum direct cost, defining constraints based on the AASTHO-LRFD 2014 and NC-207:2019 standards. The algorithm is created to properly obtain practical solutions from the engineering point of view, involving the use of discrete variables. The optimization method used is Biogeography-Based Optimization. A sensitivity analysis of the parameters of this method is performed. The results indicate that the typical projects currently used can be considerably improved to enhance their economic indexes. Based on these results, some specific design recommendations are given. In addition, future research lines are suggested based on the deficiencies of the proposed methodology.

Muscles are thermogenic organs for adult mammals and birds but can also be thermosensitive. In this respect, recent research has shown the excitability of cardiac muscle tissue when irradiated with infrared laser light. Likewise, intrinsic muscle function should give place to local thermal gradients, either because of Ca2+-ATPase thermoregulatory mechanisms or, specifically in the skeletal muscle, after intense exercise. Alongside internal thermal gradients, muscle fatigue characterizes by stressful cellular conditions. Similar to stress-like conditions has been documented in myocytes from rats, the emergence of oscillations of important biochemical species [1]. We show how a thermal gradient or a thermal pulse influences the dynamics of biochemical oscillations in a simplified biochemical model of muscle fiber and discuss the consequences in a living muscle. For this purpose, each simplified sarcomere behavior is governed according to a modified Sal'nikov model, as proposed in a previous paper [2].

Overdispersion is a phenomenon that generally occurs in the analysis of large sample sizes. In discrete data analysis, it refers to the presence of a variation higher than that implied by a reference Binomial or Poisson distributions. The proportion of nonconforming units in clinical laboratories presents high variability and, generally, overdispersion. Therefore, it is required to analyze the most appropriate control charts that overcome the limitations of traditional control charts to deal with overdispersed data. This paper performs an analysis of monitoring overdispersed process in clinical laboratories using control charts. The methodology consists of four steps: (i) Determination of the interest variable, (ii) Diagnosis of data overdispersion, (iii) Elaboration of control charts, and (iv) Analysis of results. The results show that the methodology can quantitatively determine the degree of data overdispersion and select the most appropriate control chart for monitoring the process.

Repowering the Brazilian hydroelectric park is a way to expand the use of energy from hydro sources, even in a scenario where the options to build new projects are increasingly restricted. Several technical and economic aspects must be considered when evaluating the feasibility to carry out a repowering process, where indicators are considered to choose the best option. The repowering suggests the addition of assured energy, however, electromechanical equipment improvement may occur simultaneously with automation systems. Sizing is generally precise for a hydropower plant and there is no need for repowering so that the project can increase its useful life, consequently, rehabilitation is recommended. This paper shows a methodology to evaluate intervention alternatives in a project, as well as a rehabilitation case study for the Marimbondo Hydroelectric Power Plant

Most of the time, geotechnical engineering interventions require solutions that necessarily aim for better use of the available space. Many slope stabilization techniques were developed following that assumption, and one of the most applied procedures in Brazil is the soil nailing reinforcement. These engineering techniques are constantly improving. Consequently, a continuous study of the design and behavior of soil nails is important. The technique of vertical nails reinforcement in soil nailing is recent in the Brazilian scenario. Nowadays, some constructors started to use them near the slope face when stabilizing huge excavations. This paper aims to verify the vertical nails’ efficiency in reducing horizontal displacements. We present three numerical modeling analyses using the finite elements method (FEM). The proposed model is a soil nailing of approximately 18m high in a homogeneous subsoil in São Paulo city. Comparing situations with and without vertical nails, as if an inclined face (slope), the results showed that adding those nails could reduce horizontal displacements.

How employees react to an organization’s ethical/social initiatives has little support in terms of empirical evidence. We examine employee perceptions about organizational social commitment (OSC) and its association with employee well-being (WB). The sample consists of 289 participants of a healthcare organization in Colombia. We use a comprehensive methodology for mining psychological/managerial constructs in R comprising six processes (observe, explore, confirm, explain, predict, and report). We provide information concerning the scales’ plausibility, reliability, convergent/discriminant validity, and equity. We contrast the relationship between OSC and WB by using structural equation modelling with bootstrap approaches. We examine the capability of OSC to predict WB by using machine learning methods. We found a positive relationship between the constructs, which shows that OSC is a valuable strategy for contributing to employee objectives from a ‘being well together’ perspective. The paper stimulates/facilitates future research and teaching-learning initiatives in latent variable analysis using the R language.

This paper aimed to optimize the cashier service macroprocess in a supermarket located in the Alto Paranaiba. Decision-making tools were applied, such as brainstorming, process mapping, Ishikawa diagram and PDCA cycle. The simulation type was based on the M/M/1 model, in the context of Queuing Theory. Thus, factors such as customer satisfaction and increased productivity were sought through systematic control and continuous improvement of the cashiers' service macroprocess. Finally, the alignment carried out between the PDCA cycle and the Routine Management brought an effective contribution, represented by the standardization of the macroprocess, by the construction of Standard Operating Procedures (SOPs).

This paper analyzes the impact of the COVID-19 pandemic on the student’s academic performance in the School of Engineering at Universidad Nacional de Colombia – Bogota Campus. The impact is assessed from a quantitative approach based on (i) student’s grades, (ii) student’s progress in their curriculum and (iii) dropped courses. In addition, results from a faculty survey (qualitative approach) are presented to expand some explanatory perspectives on the main academic changes during the pandemic. Results show a significant increase in the average numerical grade as well as in the probability of a course being dropped during the pandemic conditions. Furthermore, the student’s average curriculum progress per semester grew approximately 18%. A differentiated academic impact, depending on sex and family income was observed which may be included in future post-pandemic programs. The survey reflects a new faculty’s perspective on evaluation tools and methodologies.

This paper shows a general model of rectangular footings to obtain the soil minimum contact area (optimal surface) that support from 1 to n columns aligned on a longitudinal axis. The proposed model considers that the soil pressure varies linearly. The recently published models have been presented individually to obtain the soil contact area for rectangular isolated footings, rectangular combined footings that support two columns, these models present the equations, but it is not guaranteed to be the minimum area. The present research complies with the models mentioned above and can be applied to footings that support 3 or more columns, and also the minimum area is guaranteed. Also, numerical problems are shown the soil minimum contact surface for rectangular isolated footings, and rectangular combined footings that support two and three columns (unrestricted on its sides, one side restricted and two opposite sides restricted).

Currently, one of the methods to improve the properties of materials in construction is the use of nanomaterials. The objective of this paper is to review the technological advances in the application of nanomaterials, which improve mechanical properties when used in concrete, soils, pavements, among others. A total of 86 articles corresponding to the Scopus, Ebsco, Science Direc and IOP Science databases were reviewed. The studies show that with the application of nanomaterials, positive results are obtained in the improvement of the compressive and flexural strength of concrete, improvement in the stabilization of soils and in asphalt, avoiding the formation of grooves and cracks. The studies conclude that the applicability of nanomaterials in the construction industry is a good alternative from a sustainable point of view, in order to reduce the indiscriminate use of non-renewable resources

This paper presents a numerical model of an integrated 3D casing-cement-formation system, to evaluate the mechanical tensile and shear failure of the cement at the casing-cement interface as the pressure and temperature conditions of the formation and borehole vary during production. The model which includes the formation pressure, unlike others proposed, was developed by stages under finite element discretization and compared to analytical models. Results show that increasing the formation temperature increases the probability of tensile and shear failure in the cement, while increasing the wellbore temperature decreases these probabilities. On the other hand, the decrease in the well pressure reduces the probability of shear failure and increases the tensile failure. In the case of formation pressure, the opposite occurs.

This paper shows a study about nonattendance to medical appointments in the Colombian health system to determine which strategies have the greatest effect on the response variable (nonattendance) of scheduled medical appointments. Three factors were considered (calling the patient, reconfirming on the eve of the appointment, confirming understanding of the procedure), each with two or three levels randomly selected from a population. Two replicates were taken for each combination of treatments. The experimental runs were donerandomly to guarantee the absence of bias in data collection. With the above, a total of 180 experimental runs were carried out. This study aims to determine the factors that influence the population when they do not attend their medical appointments to propose a strategy that reduces this phenomenon. A design of experiments (DoE) was performed, specifically a completely randomized design (CRD) and a 3k factorial design

This paper analyses seismic noise from broadband seismic stations within the Cuban National Seismic Service, focusing on location sites, soil or rock quality at installation sites and the impact of various factors on the noise signature of these seismic stations. A brief technical description of deployed equipment is provided and the methodology for data selection and analysis is presented.The study provides annual performance assessment for each station, considering specific details for each particular case. Likewise, the effect of diurnal/nocturnal and seasonal variations on noise power spectral density (PSD) is analyzed. In addition, plotted graphs show the relationship between the occurrence of extreme weather events, such as hurricanes and cold fronts through Cuban eastern and western regions, respectively, and the increase of noise level, specifically for marine microseisms period band. Finally, the influence of instrumental variations in noise level of seismic stations is characterized.

Regardless of the advances in intelligent control the analysis and use of the human capacity to control are far from exhausted. For instance, industrial applications could be too fast or too slow for a human to control. The proposed solution in this paper starts by scaling the model of the system in time, so that it results comfortable to control. The control actions of the human are learned by a Neural Network, which is blind to the changes in the time scale, thus the Neural Network controls the scaled model and the real plant as well. The Time Scaling Controller is evaluated by controlling the angular position of a motor and the result is contrasted with a fuzzy controller and a piecewise linear controller. Time Scaling Control resulted better than the other two controllers because it has the lowest effort and the highest effectiveness among the three controllers.

Sand production is a common phenomenon in oil and gas reservoirs, which occurs when reservoir fluids exert a sufficient drag force on reservoir rocks to erode the matrix. Numerical models for sand production have been used to understand the sanding mechanisms and forecast sand-production potential of formations to design well completion, optimize production, and prevent setbacks in future operations. This paper presents a mathematical model for defining the conditions of sanding onset as well as to predict and quantify the sand rate. We also introduce fluid-flow coupling and a geomechanical and sand-production model. By using the proposed model and a set of experimental data, sanding-related variables are analyzed, and a matching process for the simulated results and forecast analysis are performed. The results show that elastoplastic constitutive models are indispensable, and a clear relationship exists between the sanding and plastic strains.

A recurring problem in Geographic-Object Based Image Analysis (GEOBIA) is the need to tune each one of the three phases involved in the process, segmentation, feature selection, and classification. This paper presents the optimization of a GEOBIA-based urban land-cover classification workflow using very-high-resolution imagery. Two classification workflows are evaluated: (i) a non-optimized workflow; and (ii) an optimized workflow. In the segmentation and classification phases, both workflows used the multi-resolution segmentation algorithm and the random forest classification algorithm. In addition, important spectral, geomorphometric, and textural features are identified as significant predictor variables for the final classification. It is shown that the classification accuracy of every land-cover category increases with optimization, resulting in an overall accuracy increase of 9.34% compared with no optimization. The results show the substantial impact that optimization has on final classification output and suggest the importance of its adoption as a good practice in GEOBIA-based land-cover classification.

This paper presents the results obtained from the synthesis and morphological characterization of different magnetite samples: La0.67-x Prx Ca0.33 MnO3.LaMn1-x Cox O3 and LaMn1-x Nix O3 at 0.13 ≤ 𝑥𝑥 ≤ 0.67 produced by a solid-state reaction mechanism and 𝐿𝐿𝐿𝐿𝑀𝑀𝑀𝑀1−𝑥𝑥(𝐶𝐶𝐶𝐶/𝑁𝑁𝑁𝑁)𝑥𝑥𝑂𝑂3 at 0.0 ≤ 𝑥𝑥 ≤ 0.5 produced by the sol-gel method. These samples were characterized using X-ray diffraction spectroscopy and by measuring electric resistivity and magnetic susceptibility which were carried out as a function of temperature. Notably, the effects of strain and compressive strength on the lattices of magnetite samples were highly dependent on the concentration of 𝑃𝑃𝑟𝑟, 𝐶𝐶𝐶𝐶, and 𝑁𝑁𝑁𝑁. Moreover, the transition temperatures of metal-insulator and ferromagnetic-paramagnetic phases also largely depend on these strength effects, e.g., at higher concentrations of 𝑃𝑃𝑟𝑟, effects of increased strain strength were observed, relocating the shifts of ferromagnetic-paramagnetic transitions to lower temperatures. On the other hand, effects of increased compressive strength were observed at higher concentrations of 𝑁𝑁𝑁𝑁 and 𝐶𝐶𝐶𝐶, relocating the shifts of ferromagnetic-paramagnetic and metal-insulator transitions to higher temperatures.

Purpose: The objective of this paper is to evaluate the quality of the public transportation system service in the city of Morelia, Mexico. Methodology: According to the needs of the study, the expectation-perception SERVQUAL model was adapted, which consists of 5 variables: Tangibility, Reliability, Responsiveness, Security and Empathy, and 25 items. The subjects of the study were users over 15 years old who regularly use the system. Users answered the expectations questionnaire the before getting on the transport vehicle and for the perceptions questionnaire, users answered it after getting off the vehicles. For each questionnaire, the sample was 392, a total of 784 people participated in the study, and their answers where measured using a five-point Likert-type scale. Results: The mean comparison shows that respondents have a high expectation level, with 4 points or above, whereas their perception level is 3, with gaps between 0.5 and 1 points.

Chlorogenic acid (CGA), a high value-added phytochemical used by the pharmaceutical and food industries, is found in residues and byproducts of the coffee industry. This paper presents a methodology to identify the adequate solvents to extract CGA from coffee pulp based on Hansen solubility parameters (HSPs), risk assessment, sustainability evaluation, and an economic analysis. In total, 16 solvents with different physicochemical properties, which are commonly used in the industry for extraction processes, were evaluated. According to the results, the most appropriate solvents are water, methanol, ethanol, n-propanol, acetone, t-Butyl alcohol, ethyl acetate, acetic acid, benzyl alcohol, and phenol. However, water, ethanol, and a mix of them are the most advisable solvents because they have the lowest Ra, their HSPs are near those of CGA, they are easy to handle according to CHEM21’s Risk Assessment guide, they have a lower carbon footprint, and they are less expensive solvents.

Interactive Digital TV (iDTV) enhances viewers’ experience and participation by engaging them with an active role. The development of interactive software requires the employment of usability criteria to provide satisfactory experiences for users. In addition, the diverse characteristics of television programs require efficient processes for interactive software development. In Latin America, the process of implementing DTV is in progress, so the current stage of development of interactive applications is too incipient and immature to support industrial, quality-level development. This paper proposes combining software reuse strategies, specifically, software product lines (SPLs) and user-centered interaction design patterns, to improve productivity and quality. A generic feature model for the automatic generation of iDTV applications and an SPL-iDTV tool that supports the model are presented. The proposal is evaluated with two studies: an experiment that attempts to reproduce real application prototypes that were originally developed manually, through the use of patterns, and an evaluation of the quality of the SPL.

This paper presents “EspiNet V2” a Deep Learning model, based on the region-based detector Faster R-CNN. The model is used for the detection of motorcycles in urban environments, where occlusion is likely. For training, two datasets are used: the Urban Motorbike Dataset (UMD-10K) of 10,000 annotated images, and the new SMMD (Secretaría de Movilidad Motorbike Dataset), of 5,000 images captured from the Traffic Control CCTV System in Medellín (Colombia). Results achieved on the UMD-10K dataset reach 88.8% in average precision (AP) even when 60% motorcycles were occluded, and the images were captured from a low angle and a moving camera. Meanwhile, an AP of 79.5% is reached for SSMD. EspiNet V2 outperforms popular models such as YOLO V3 and Faster R-CNN (VGG16 based) trained end-to-end for those datasets

Based on the results of research papers reflected in the scientific literature, the main examples, methods and perspectives for the development of technical textiles are considered. The focus of this work is to concentrate the results obtained for different textile applications (technical textiles) through the use of biodegradable polymers modified and improved with nanoparticles. The techniques for obtaining polymeric nanocomposites, finishing processes, type and structure of textiles are specified. In general, key aspects are identified for a better understanding of the technical challenges and physicochemical effects of the fibers.

In recent decades, transportation planning researchers have used diverse types of machine learning (ML) algorithms to research a wide range of topics. This review paper starts with a brief explanation of some ML algorithms commonly used for transportation research, specifically Artificial Neural Networks (ANN), Decision Trees (DT), Support Vector Machines (SVM) and Cluster Analysis (CA). Then, these different methodologies used by researchers for modeling travel mode choice are collected and compared with the Multinomial Logit Model (MNL) which is the most commonly-used discrete choice model. Finally, the characterization of ML algorithms is discussed and Random Forest (RF), a variant of Decision Tree algorithms, is presented as the best methodology for modeling travel mode choice.

Pseudonym change schemes have been studied in VANETs to guarantee the property of untraceability of the vehicles. This paper proposes a new condition based on the assumption that if there are no malicious vehicles around when a synchronous change triggers, there is no risk of tracking, and the pseudonym change defers until a time threshold. Thus, our proposal based on a synchronous strategy to increase the anonymity set, adds to the change condition, the checking of the reputation status of the neighbouring vehicles. The reputation status is the result of discretizing the reputation score of the vehicles and it is part of the periodically broadcast beacon messages. The proposal was evaluated through simulations using a real scenario. The results showed an optimization in the use of pseudonyms maintaining similar anonymity levels with other schemes.