Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

This experimental study evaluates the influence of the partial addition of Caesalpinia Spinosa ash (CS) or Tara ash, and Fiber Cement (FC) in asphalt mixtures for flexible pavements. Mineral filler replacement percentages of 1,0%, 1.5% and 2,5% were analyzed using the Marshall and Lottman tests, with the aim of determining their effect on stability, creep and resistance to moisture. This mixture improves its properties, therefore. tend to be applicable to roads. A total of 51 briquettes of selected asphalt mixture were manufactured. The distribution of specimens was organized into two groups: the first composed of 27 specimens for the Marshall test and the second by 24 for the Lottman test. From the pattern set (0% modification), 18 briquettes were prepared for the Marshall test, and 6 were intended for the and Lottman tests. In the case of the mixtures modified with additives at concentrations of 1,0%, 1,5% and 2,5%, 3 and 6 specimens were prepared for each test, respectively. The results of the Marshall test indicate a decrease in stability compared to the standard sample (1289,9 kg), with values of 1271,9 kg, 1198 kg, and 1256 kg for 1.0%, 1,5%, and 2,5% CS+FC, respectively. Creep values ranged from 2,91 mm for the standard sample to 3.5 mm, 3.26 mm, 3.08 mm, and 2,93 mm, depending on the addition percentage. Finally, the indirect tensile strength test (TSR) showed values of 82,7%, 79,6%, 81,2%, and 76,7%.

The study characterized the main failures in visible structural members of the Dean's Office of Health Sciences building at the Lisandro Alvarado Centroccidental University in Barquisimeto, in order to determine the mechanism that allowed these failures to develop. A visual inspection of the building was applied. Construction began in 1974. The structure is a reinforced concrete structure with a clean finish, consisting of two levels, and a construction area of 12,744.08 m2 on the ground and upper floors, respectively, and 11,333.81 m2 for the roof. It was determined that the exposure environment is C3, which makes the concrete sensitive to carbonation damage. During the survey of the symptoms of the failures, it was verified that the failure mechanism begins with the roof; the failure of the asphalt layer represents 34,09% of the failures. On the upper floor, efflorescence is 42.34%, and on the ground floor, 64,29%. It is presumed that the main cause of the failures is due to the lack of maintenance that triggered the deterioration, so a plan must be made for the structural, roof, and drainage subsystems, which will contribute to extending the useful life of this important building

The stabilization of clayey soils is a persistent challenge in civil engineering, particularly in regions with infrastructure projects in expansive soil areas. This study evaluates the effectiveness of incorporating eggshell ash (CCH) to improve the mechanical properties of clayey subgrades on Av. Alisos, Anccohayllo, Apurímac, Peru. The research included field sampling and laboratory tests to analyze the California Bearing Ratio (CBR), compaction characteristics, and plasticity of soil samples with varying CCH percentages of 10%, 15%, and 20%. Results showed significant improvement in CBR values, with a 71,79% increase using 20% CCH, indicating a substantial increase in soil bearing capacity. Additionally, the Maximum Dry Density (MDD) increased and the Optimum Moisture Content (OMC) decreased, suggesting better soil compaction and stability. Although the effect on plasticity was not statistically significant, a slight reduction was observed. This study concludes that CCH is a viable and sustainable additive for stabilizing clayey subgrades, offering an environmentally friendly alternative through the reuse of agricultural waste

The aim of this study is to estimate the employment and domestic value added generated by manufacturing exports in North America countries between 1995 and 2020. To achieve this, a multi-regional input-output model is applied, utilizing data from the Trade in Value-Added (TiVA-OECD) and Trade in Employment (TiM-OECD) databases. The results indicate that economies engage in manufacturing activities with different inputs to domestic indicators. In Mexico, exports are generators of employment, in the United States, they contribute to domestic value-added, and in Canada, the composition is intermediate. It is concluded that developed countries (the U.S. and Canada) participate in stages of greater generation of domestic value added. The originality and contribution of this document lies in the application of a widely used method for the analysis of the decomposition of value added to the employment variable.

This paper addresses the relationships between drugs and culture in the fentanyl era in the city of Tijuana, on Mexico’s northern border, based on a review of newspapers, an analysis of governmental videos on addiction prevention, and ethnographic material. Drawing on the work of Michel Aglietta and others, we propose the existence of an addiction regime that (re)produces discourses on substance use and its institutional treatment, generating a contentious language regulating the forms of signification around drugs, and the diverse fashions in which the state manages populations involved in the drug economy, particularly in social contexts where structural conditions of despair prevail.

Context: The use of alternative materials in construction requires the implementation of new methods that allow addressing the problems associated with the manufacture of traditional composite materials. In recent years, additive manufacturing techniques have attracted the attention of entrepreneurs and researchers due to its ease in processing complex designs and its low processing times. However, there is little information about the mechanical performance of composites obtained from the processing of biopolymer filaments reinforced with plant fibers. Method: We evaluated the mechanical behavior of 3D-printed biocomposites subjected to axial tension loads. For the experimental design, filaments were constructed using 90% polylactic acid granules and 10% pulverized rattan fibers. The properties of the filaments were analyzed through microscopy, density, thermogravimetry, roughness, and hardness tests. The specimens were printed according to the dimensions specified in ASTM D638, and the effect of infill density and printing orientation on their physical and mechanical properties was analyzed. A statistical analysis was carried out in order to formulate equations allow predicting the behavior of the material based on the printing parameters considered. Results: The obtained filaments were characterized and compared against their unreinforced counterparts. The specimens were printed using the fused deposition method. The effect of the printing parameters on the physical and mechanical properties of the stressed biocomposite was determined, and the impact of the studied variables was analyzed using a central composite design. Conclusions: The surface roughness of the samples increased with the printing orientation and decreased as the infill density increased. Hardness and tensile strength increased significantly with increasing infill density, and they decreased with an increasing printing angle. The probes printed with 80% infill showed a notable increase in rigidity.

Context: This paper proposes a method for the prediction of monthly precipitation in the department of Boyacá using models based on deep neural networks (DNNs). These approaches have achieved significant improvements in prediction accuracy when compared to traditional methods. Method: Data with a spatial resolution of 0.5° were extracted from CHIRPS 2.0 and subsequently preprocessed for the implementation of two approaches based on recurrent neural networks (RNNs) with long short-term memory (LSTM) and ConvLSTM architectures, aiming to provide accurate predictions of monthly precipitation in the studied region. Objectives: The goal of this time series analysis is to predict monthly precipitation and develop accurate models that can forecast future rainfall patterns based on historical data. This aids in water resource management and agricultural planning, as well as in mitigating the impacts of droughts or floods. Results: According to the results obtained, the LSTM model stands out for its robustness in terms of performance metrics, such as a lower mean squared error, a lower root mean squared error, and a coefficient of determination closer to 1. This demonstrates its higher accuracy compared to the ConvLSTM model.Conclusions: Deep learning models, especially RNNs with LSTM, are effective tools for predicting crucial climate data.

Context: This paper employs fuzzy logic in the unconventional adjustment of suppression and weighting factors within a generalized predictive controller (GPC).Method: The control strategy is applied to a level plant featuring interconnected concentric tanks. For the tuning process, a fuzzy proportional-integral-derivative PID controller is compared against the proposed GPC equipped with fuzzy suppression and weighting parameters. Evaluation metrics related with response time and integration criteria are employed in this comparisonResults: The results demonstrate the superiority of the GPC combined with fuzzy logic over the fuzzy PID controller. Dynamic weighting factors contribute to enhanced control performance, as evidenced by the evaluation metrics. Conclusions: The proposed approach proved to be effective in improving control performance in the tested system. This approach offers a promising alternative to traditional methods, especially in systems where dynamic adjustments are beneficial.

Context: This paper presents the design and implementation of a virtual laboratory developed as a pedagogical support tool for courses in mechanisms analysis and synthesis within Mechanical Engineering programs. Method: Our virtual laboratory was developed using GeoGebra, Moodle, and Matlab. The design methodology was structured into four key stages: requirements analysis, conceptual design, content development, and implementation and evaluation. Results: The outcome is a comprehensive virtual laboratory framework comprising 12 interactive exercises focused on the analysis and synthesis of planar mechanisms. This paper outlines the functional features of the virtual laboratory, including its graphical user interface, user guide, instructional practices, and assessment procedures – demonstrating its value as an effective tool to support and enhance both teaching and student learning. Conclusions: The virtual laboratory allowed students to conceptualize through the visualization of kinematic and dynamic variables, offering a complementary and interactive alternative to traditional theoretical instructions. This aligns with active learning strategies, as the teacher reported greater student engagement. Students advanced at their own pace through the exercises and were able to observe how geometric and functional modifications in mechanisms influence their kinematic and dynamic behavior.

Context: Micropiles have been mainly employed as soil reinforcement or supporting elements. As load-recovering elements, they have been used in pile groups where one of the elements has turned out to be defective or incomplete. This type of use has not been directly reported in the literature, so it is important to generate knowledge about the conditions to be considered when evaluating the use of micropiles as replacements for defective piles. Method: This research verified and described the settlement behavior and load distribution of both piles and micropiles for five proposed models. The results were obtained through the analytical methodology by Poulos and Davis for pile group settlement, analyzing the influence of three variables on micropiles: position in the cap area, spacing, and quantity. Results: The load distribution in the micropiles showed greater uniformity as their number increased. Likewise, a load increase was observed as the distance between the micropiles and the upper left corner of the cap decreased. With greater spacing and micropile count, the settlements decreased. Conclusions: In order to use micropiles as load-recovering elements in existing foundations, it is convenient to consider variables such as quantity, position, and spacing, as they influence both the load distribution and the settlements of the structure.