ACI Avances en Ciencias e Ingenierías is an international, multidisciplinary, diamond open-access scientific journal that publishes two issues per year (May and December) in English and Spanish. It publishes original research, reviews, and communications in sciences and engineering, promoting methodological rigor, transparent peer review, and open science practices. The journal prioritizes interdisciplinary contributions within STEM and aims to expand international knowledge exchange with broader social impact. Before submission, authors must ensure that their manuscript aligns with the aims and scope of the journal. ISSNe: 2528-7788 ISSN: 1390-5384 Editorial: USFQ PRESS
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Effect of oregano essential oil and ozonation as an alternative for shelf-life extension in cooked beans (Phaseolus vulgaris L.)
The objective of this study was to evaluate the efficacy of combining oregano essential oil (AOE), and ozone in extending the shelf life of cooked beans (Phaseolus vulgaris L.), using an AxB factorial design: a control (T0), and four combinations of ozone (0.25 and 0.50 ppm), with AOE (0.30 % and 0.50 %), for 21 days of storage at 4°C. The beans were hydrated (3:1 water: bean), cooked for 90 minutes, cooled with ozonated water, coated with AOE emulsifier in 0.5 % Tween 80, and packaged in polyamide and polyethylene bags. Physicochemical parameters (pH and acidity), microbiological parameters (mesophilic aerobes, total coliformes, Escherichia coli, Staphylococcus aureus, and Salmonella spp.), and sensory attributes (color, odor, flavor, texture, and acceptability) were evaluated. ANOVA and Tukey’s test were applied (p < 0.05). There were statistically significant differences (p < 0.001), between treatments and control during storage. T3 presented the lowest acidity (0.08 g/100 g), and the control the highest (0.17 g/100 g). T0, T1 and T2 maintained slightly acidic pH (5.2–5.5), T3 and T4 exceeded pH 7.0. T3 achieved the greatest microbial reduction in mesophilic aerobes (1.37 log₁₀ CFU/g), and total coliforms (2.60 log₁₀ CFU/g), differing significantly from the control. Sensorially, T3 obtained the highest scores in all attributes until day 21. It is concluded that the joint application of ozone and AEO, especially in T3, represents a viable and effective technological alternative to preserve the physicochemical, microbiological and sensory quality of cooked beans.
Adriana Geovanna Yanchaliquin Yanchaliquin
Copyright (c) 2025 Adriana Geovanna Yanchaliquin Yanchaliquin, Renato Agustín Renato Agustín https://creativecommons.org/licenses/by-nc/4.0
Unbalance in ac motors with variable speed
The study aims to analyze the imbalance in alternating current motors with variable speed, specifically in asynchronous motors, to identify and control resonance and instability phenomena that arise during operation at different speeds. These phenomena can cause excessive vibrations, damage to mechanical components, and reduced motor lifespan. To achieve this, a dynamic analysis of a three-phase rotor was conducted using a mathematical model that considers the stiffness and damping coefficients of the bearings, as well as excitation forces and lubrication conditions. The rotor was divided into three sections, and its behavior under unbalanced conditions was simulated using dynamic analysis software (Rotor Dynamics Analysis). Additionally, practical vibration measurements were taken using a CSI 2130 analyzer to validate the simulation results. The results revealed the presence of two critical speeds, one at 800 rpm and the other at 1600 rpm, where maximum vibration amplitudes and resonance conditions were observed. These critical speeds pose a significant risk to motor operation, as they can lead to instabilities and damage to mechanical components. The study concludes that it is essential to avoid operating the motor at these critical speeds to prevent failures and ensure safe and efficient operation. Furthermore, it highlights the importance of conducting modal analysis and regular preventive maintenance to identify and mitigate potential issues before they become critical. The findings provide valuable insights for optimizing the operation of asynchronous motors in industrial applications, particularly in processes requiring variable speed, thereby contributing to improved energy efficiency and reduced maintenance costs.
Copyright (c) 2025 Jose Luis Hernández Corona, Jonny Carmona Reyes, Román Daniel Romero Mitre https://creativecommons.org/licenses/by-nc/4.0
This editorial requires no abstract
Copyright (c) 2026 Oscar Camacho https://creativecommons.org/licenses/by-nc/4.0
Selection of sleeping perches by the Gem Anole, Anolis gemmosus O'Shaughnessy 1875, in a cloud forest in Ecuador
The selection of sleeping perches plays a critical role in predator avoidance, territorial defense, access to feeding areas, and reaching breeding sites. This behavior has been widely studied across various taxa, including the diverse lizard genus Anolis. For Anolis gemmosus, however, only one previous study has addressed sleeping perch selection, focusing solely on physical variables of the perches. In this study, we incorporate additional variables—such as the sex and size of the lizards—and assess their effect on perch type and leaf area. Our results reveal a significant relationship between individual size, particularly in males, and perch area. This pattern may reflect strategies for predator avoidance, or territory maintenance, or may simply result from the higher availability of leaves within a specific range of area in the habitat of A. gemmosus.
Copyright (c) 2025 Martín Carrera https://creativecommons.org/licenses/by-nc/4.0
Consensus solution of the focal mechanism of the MW 8.8 earthquake in Kamchatka and the resulting seismic deformation fields
The Mw 8.8 Kamchatka earthquake of July 29, 2025, represents one of the largest seismic events recorded in the Kuril-Kamchatka subduction zone. This study synthesizes and compares the focal mechanism solutions reported by major seismological agencies to derive a representative consensus double-couple solution and to model the coseismic deformation fields generated by the rupture. The angular quadratic mean difference among strike, dip, and rake parameters was used as the main metric of similarity between mechanisms. The consensus solution (strike= 203.5°, dip = 22.7°, rake= 70.1°) is consistent with megathrust faulting on the subduction interface. Based on the USGS finite rupture model, surface displacement and strain fields were computed using Okada’s (1985) elastic dislocation formulation. The results reveal horizontal displacements toward the trench, vertical subsidence to the northwest, and uplift to the southwest of the epicenter, with strain patterns correlating with aftershock distribution. The low angular dispersion (maximum rotation = 28.4°) confirms convergence among agency solutions. These findings contribute to a more reliable representation of rupture parameters and support regional seismic hazard modeling.
Copyright (c) 2025 Amilcar Carrera Cevallos https://creativecommons.org/licenses/by-nc/4.0
Design of a circular and sustainable process for the extraction and drying of powdered polyphenols from cocoa bean husks for use in the cosmetics industry
Cocoa bean husks are an abundant waste product that is often discarded despite its valuable bioactive compound content. This study develops a sustainable process, guided by circular engineering principles, to obtain powdered polyphenols through extraction and drying. The study focused on identifying operating conditions that maximize polyphenol recovery, reduce resource consumption, and ensure the stability of the final product. The results show that the proposed process yields a powder rich in polyphenolic compounds with functional properties suitable for integration into cosmetic products. The proposal demonstrates that it is possible to transform agro-industrial waste into a high-value ingredient in line with the demand for sustainable alternatives in the cosmetics industry.
Copyright (c) 2025 Ing. Samantha Isabel Valladares Ladino, Ing. Germán Marcelo Layedra Gadvay, Mateo Valencia, Vicente Obando, Micaela Jaramillo, Dr. José Alvarez-Barreto https://creativecommons.org/licenses/by-nc/4.0
Experimental flexural analysis of steel-fiber-reinforced concrete beams
The use of steel fibers in concrete has been widely documented in numerous engineering applications due to the advantages they provide in terms of strength, crack control, and energy absorption capacity. However, in Ecuador, there is still limited knowledge among construction professionals regarding their structural properties and benefits. This research arises from the need to overcome the inherent limitations of conventional concrete, particularly in its post-elastic behavior and its response to cracking. This paper presents the results of an experimental study in which concrete mixtures with a nominal compressive strength of 24 MPa were designed, and the flexural behavior of four beam typologies was evaluated: plain concrete, steel fiber-reinforced concrete, conventional reinforced concrete, and concrete with a dual reinforcement system (steel fibers and reinforcing bars). Twelve specimens were tested under static loading following the procedure established in ASTM C1609. The results show that an appropriate combination of cement, aggregates, and a fiber dosage of 0.56 % by volume increases the ultimate flexural strength by 33.63 % in plain concrete beams and by 12.85 % in reinforced concrete beams. A significant improvement in ductility was also observed, with increases of 187.23 % in plain concrete beams and 38.02 % in reinforced concrete beams. The findings demonstrate the effectiveness of incorporating steel fibers in structural elements subjected to flexure, showing improvements at both mechanical and structural levels. The presence of fibers promotes a more uniform stress distribution, reduces tensile demands on longitudinal reinforcement, and enables more efficient utilization of reinforcing bars, resulting in increased load-carrying capacity for sections equivalent to those of conventional reinforced concrete. Additionally, enhanced energy absorption capacity and a significant reduction in crack width were confirmed.
Copyright (c) 2025 Jonnathan Molina, Pilar Naspud-Uruchima, Xavier Nieto-Cárdenas https://creativecommons.org/licenses/by-nc/4.0
Evaluation of some physical and physiological quality attributes of sweet corn (Zea mays sacharata) seeds under different storage conditions and harvesting season
In Colombia, sweet corn (Zea mays saccharate) is of great importance for producers and consumers of fresh grain. Agrosavia has developed a new variety of sweet corn for small producers in the Caribbean region who can produce their own seed. The study aimed to evaluate the physiological quality of sweet corn seed under different storage, packaging and harvesting conditions. Two experiments, cold storage and environmental conditions, were established at the Analytical Chemistry Laboratory of AGROSAVIA, where the effect of packaging and harvest time on germination, viability, temperature and humidity of sweet corn seeds was evaluated. The seed germination and viability under cold storage conditions (10 °C and 60 RH) were higher (P<0.05) when stored in plastic packaging (81.9 %) compared to paper (76.3 %). For environmental temperature conditions (28 °C and 85 RH), the highest germination percentage (P<0.05) was presented in the plastic packaging from 60 to 120 days of storage in seed harvested at 90 days. According to this study, sweet corn seed can be harvested at physiological maturity (90 days) and packaged in plastic containers preserving the quality for up to 120 days. Paper bag treatment germination can be drastically reduced after 60 days of storage.
Generation of technologies in the cultivation of corn in Ibero-America
Copyright (c) 2024 Liliana Atencio Solano, Jos´é Tapia Coronado, Wilson Barragán Hernández, Emiro Suárez Paternina, Abelardo Tulio Diaz Cabadiaz , Iván Javier Pastrana Vargas https://creativecommons.org/licenses/by-nc/4.0
Inversion of two-flux and four-flux radiative transfer models in WO3-NiO electrochromic devices
Intrinsic and extrinsic scattering and absorption coefficients (S&A-C) of four inorganic electrochromic device (ECD) samples were determined at their bleached-off optical state (BOOS, 0 V) and at their colored-on optical state (COOS, +3 V DC). The same inversion procedure previously applied to suspended particle device (SPD) and polymer-dispersed liquid crystal (PDLC) samples, approximated for a single layer sandwich structure, was used here for a third smart window technology, based on redox reactions. The four studied ECDs incorporated cathodic WO3 and anodic NiO layers corresponding to the four possible combinations of two thicknesses for each material —single (120 nm) and double (240 nm)— within their sandwich structures. The analysis of their S&A-C was performed in three stages. First, determination of optical constants using the collimated solutions of the four-flux model (4FM) from collimated transmittance and reflectance (T&R) measurements. Second, estimation of extrinsic S&A-C from the two-flux model (2FM) using total (collimated + diffuse) T&R data. Third, extraction of intrinsic S&A-C from the diffuse 4FM solutions by means of diffuse T&R data, employing the diffuse interface reflectance, an approximate average crossing parameter, and the forward scattering ratio. Although light scattering was found to be weak, absorption for the COOS showed a clear dependence on the WO₃–NiO active layers thicknesses: neutral gray ECD11 (single WO3–single NiO), brownish gray ECD12 (single WO3–double NiO), bluish gray ECD21 (double WO3–single NiO), and dark gray ECD22 (double WO3–double NiO). As expected, similar optical appearances were observed in the BOOS for the four ECDs. The values weighted by the CIE 1931 standard observer color matching function (ȳ) indicate that increasing the WO3 thickness twofold leads to a larger absorption coefficient increment than a twofold increase in the NiO thickness. The single-layer 4FM implementation adopted in this study provides reliable agreement in the 250–1500 nm wavelength range, while fitting inaccuracies appear beyond 1500 nm (i.e., in the 1500–2500 nm region) between the calculated and the measured diffuse transmittance at BOOS, for ECD11 and ECD22, and at COOS, for ECD11. No fitting inaccuracies were observed between the calculated and the measured diffuse reflectance. Concerning the 2FM study, an excellent agreement in fitting was observed between the calculated and the measured total T&R for the four ECD samples.
Copyright (c) 2025 David Barrios, Carlos Alvarez, José Miguitama, Armando Fabrizzio Lopez-Vargas https://creativecommons.org/licenses/by-nc/4.0
Microcracking of reinforcing bars used in informal housing construction: Riobamba case study
This study investigates the relationship between the method used to bend reinforcing bars and the initiation of microcracks in reinforcing steel used in informal housing in the city of Riobamba, Ecuador. Two bending techniques were compared: the traditional method and the method carried out in accordance with Standard NTE INEN 2167. Field surveys were used to identify the most commonly used rebar diameters and bending practices. Twenty samples of 10 mm and 12 mm diameter rebars were analyzed, including straight sections and rebars bent at 180°, using metallographic tests and scanning electron microscopy (SEM). The results show the absence of microcracks in the unbent samples and in those bent with a semi-automatic machine under standard conditions, while traditional bending generates microcracks located in the inner area of the bend, associated with stress concentrations in the longitudinal ridges. Analysis of the cumulative length of microcracks indicates that the diameter of the bar has a significant influence on the level of microcracking under the conditions studied. The findings highlight the importance of complying with standard bending procedures to preserve the ductility of reinforcing steel and improve the performance of reinforced concrete structures under cyclic loads in informal construction contexts.
Copyright (c) 2025 Evelyn Melisa Cabrera Alvarez, Teresa del Pilar Sáez Paguay, Luisa Paulina Viera Arroba https://creativecommons.org/licenses/by-nc/4.0
Generation of liquid fuels through the pyrolysis process from polypropylene and polystyrene for energy utilization
To valorize polypropylene (PP) y polystyrene (PS) waste by generating liquid fuels, a pyrolysis process was conducted using a horizontal fixed-bed Shaftherm reactor. Temperature ramps of 500, 600, y 700°C with times of 60, 90, y 120 minutes were used. At temperatures below 500°C, the process was incomplete, yielding only melted polymer. Starting from 500°C, the process was complete, improving with reaction time. For PP, a liquid fraction yield of 56,97% at 500°C y 60 minutes was recovered, increasing to 86,64% at 700°C. For PS, the best yields were obtained at 600°C, with recoveries between 90,36% y 92,63% at 90 minutes. The liquid fractions from PP at 500°C, containing C2-C10 hydrocarbons, resemble commercial extra gasoline C4-C10, while the PS fractions are rich in styrene y C2-C18 chains. Highlighting their high energy potential, PP showed a calorific value between 42 236,64 kJ/kg y 45 005,34 kJ/kg, y PS between 37 401,38 kJ/kg y 43 107,50 kJ/kg. The comparative analysis of the calorific value between the generated liquid fractions y commercial fuels (diésel y gasoline) demonstrated that the obtained products have high potential as energy sources, with PP having a higher calorific value than diésel y extra gasoline. Quality results, such as density y viscosity, were encouraging for industrial applications, y chromatographic analysis revealed the presence of valuable compounds, suggesting their potential use in the chemical industry. Although some parameters did not meet INEN standards, the liquid fractions show significant similarities with commercial fuels, suggesting their viability as an alternative energy source.
Copyright (c) 2025 Bryan Montalvo Verduga https://creativecommons.org/licenses/by-nc/4.0
Sustainable ethylene production in Ecuador: Comparative analysis between naphtha cracking and biomass-based processes using Andean potato waste
Ecuador, a country highly dependent on its oil industry, faces the need to import petroleum derivatives due to the lack of a developed petrochemical sector. This study comparatively assesses the technical, economic, and environmental feasibility of three routes for ethylene production, focusing on more sustainable and environmentally friendly processes. The first, the traditional linear process based on thermal cracking of naphtha, is noted for its technological maturity and lower initial costs, but operates under the "extract, produce, dispose" sequence, leading to a high environmental impact due to the substantial energy required and significant greenhouse gas emissions. In contrast, the two proposed circular routes utilize potato agricultural waste as biomass for bio-ethylene production: (a) fermentation to obtain bioethanol followed by catalytic dehydration and (b) electrocatalysis of methane derived from residual biomass. The study's results indicate that while these routes face technical and economic challenges, such as low yields, additional equipment for raw material processing, and higher initial costs, they offer environmental benefits aligned with green chemistry principles, including carbon emission reduction, use of renewable raw materials, and increased energy efficiency. Of the two circular processes analyzed, fermentation is considered the more applicable option due to biomass availability and process maturity in the local industry, despite having a cost 2.6 times higher than the linear process. While naphtha-based ethylene production remains the most viable in economic and technological terms, the development of a sustainable bio-ethylene industry still faces challenges in scalability, yields, and high initial costs but would allow the valorization of agricultural waste, diversifying the country's production matrix and positioning Ecuador as a leader in green innovation in Latin America.
Copyright (c) 2025 Gabriel Vaca, Sonia Quiroga Quisaguano, Kimberly Rizzo, Dimas Pincay, José Alvarez-Barreto https://creativecommons.org/licenses/by-nc/4.0
Activity patterns of the Andean cottontail Sylvilagus andinus (Lagomorpha: Leporidae) in a peri-urban context in a ravine in Puembo, Quito valley, Ecuador
The urban ravines in Quito, Ecuador, harbor the last remnant vegetation of the city but face increasing pressure from urbanization and introduced predators. We analyzed the daily activity patterns of the Andean cottontail (Sylvilagus andinus) in a ravine of the Chiche River (Puembo, Quito) using camera-traps at night between February and September 2025, and after 304 trapping nights, a total of 176 rabbit records were obtained. Cottontails were mainly nocturnal, with peak activity between 2:00 and 3:00am, and showed a significant seasonal shift, with activity concentrated in the early evening (6:30-7:30pm) during the rainy season and extending later during the night (2:00-4:00am) in the dry season. Temporal overlap with introduced predators such as dogs and cats was moderate but our data is most likely not representative, as it is based on few events (n=5). Our findings suggest that S. andinus varies from its main temporal activity, responding to seasonal and possibly anthropogenic factors in these urban ravines. This study establishes a baseline for future research on native mammals living in urbanization processes in Andean cities such as Quito.
Copyright (c) 2025 Elias Viteri-Basso, Rebecca Zug https://creativecommons.org/licenses/by-nc/4.0
Design, Analysis and Comparison of Hybrid and Non-Pneumatic Tyres
Non-Pneumatic Tires, or airless tires, are load-bearing tires that do not require air pressure for that purpose they employ flexible spokes made of thermoplastic Polyurethane. NPTs are characterized by elastic spokes, durability, and resistance to wear, which makes them quite preferable for military, defense, industrial, and space vehicle applications. However, they are somewhat limited in their ability to absorb shocks and comfort, thus limiting their application in commercial vehicles. Hybrid tires provide a solution that unites the merits of NPTs and conventional pneumatic tires. They consist of flexible spokes together with pressurized air, thus giving them properties from both sides-NPTs durability and comfort of a conventional tire. This study is highly focused and presents a comparison of NPTs and hybrid tires. Finite Element Analysis of both models indicates that with respect to strength and comfort, hybrid tires fare very well for civilian vehicles, though their strength may be slightly less than that of NPTs.
Copyright (c) 2025 Shamsher Ali, Syed Aliyar Shah, Moiz Ahmad, Syed Muhammad Zain, Ahsan Rehman Khan https://creativecommons.org/licenses/by-nc/4.0
Light-frame wood shear walls: A review of the state-of-the-art
Due to the damage caused to timber structures during the 1994 Northridge earthquake, research focused on understanding, designing, and improving the seismic response of lightweight timber framed shear walls has experienced a remarkable growth. The main objective of this state-of-the-art review article is to synthesize the innovations and findings found during the last decade, which are detailed in research articles found in the ScienceDirect database. In order to provide a starting point to serve as a reference to explore future lines of research. The methodology indicated in the PRISMA statement has been adopted to give an adequate diagnosis of the bibliometric information found, additionally by using the VOSviewer tool bibliometric maps based on authors were made. It should be noted that aspects of fire resistance or other environmental factors have been excluded in this work. The presentation of the results is organized according to two key aspects identified in the literature: experimental studies and numerical modelling of light-framed walls.
Copyright (c) 2024 Jaime Joan Encalada Oña, Lenin Alvarez, Diego Quizanga, Luisa Viera https://creativecommons.org/licenses/by-nc/4.0
Mechanical characterization of a material composed of polyester resin reinforced with eucalyptus bark
This study aims to evaluate the mechanical performance of a composite material manufactured with different proportions of polyester resin matrix and eucalyptus bark fiber reinforcement. Specimens were prepared with volumetric fractions of 90% matrix - 10% reinforcement, 80% matrix - 20% reinforcement, and 70% matrix - 30% reinforcement, with randomly distributed fibers. Tensile, flexural, and impact tests were conducted according to ASTM standards to determine the mechanical properties of the composite. The results showed a decrease in the tensile and flexural strength of the composite compared to the pure resin, which was attributed to the presence of stress concentrators and low adhesion between the fibers and the matrix. However, an increase in the elastic modulus and impact energy absorbed by the composite material was observed. The combination of 70% matrix and 30% reinforcement presented the best balance of mechanical properties among the different formulations studied. This study highlights the potential of natural fiber-reinforced composite materials as a sustainable alternative to synthetic fibers, taking advantage of the renewable resources available in Ecuador and reducing the environmental impact associated with the production of traditional composite materials. The obtained results contribute to the development of new ecological materials with applications in various industries, promoting the use of natural fibers and encouraging research in this field.
Copyright (c) 2024 Jimmy García, Byron Darío Analuiza Hidalgo, Wilson Gabriel Agualongo Amangandi, Milton Xavier Remache Sasig https://creativecommons.org/licenses/by-nc/4.0
Design and validation of a detection system for the electromagnetic component of cosmic rays detection of using log-periodic antennas
This study presents the design and evaluation of a detection system for the electromagnetic component of Extensive Air Showers (EAS) generated by ultra-high energy cosmic rays (UHECRs). The proposed approach employs log-periodic antennas and a software-defined radio (SDR) system for signal acquisition and analysis in the 20-80 MHz frequency range. Simulations were performed using ANSYS, and experimental tests with a vector network analyzer, yielding reflection coefficients below -10 dB. Data acquisition was performed via an SDR-based system, incorporating an automatic triggering mechanism and digital filtering. Data were collected over 47 days with a sampling frequency of 1 Hz. The results indicate the detection of signals in the 40-60 MHz range, showing temporal variability and patterns that suggest the presence of cosmic-ray-induced events. However, cross-validation with particle detectors is required to confirm these findings. This work demonstrates the feasibility of radio-based cosmic shower detection and highlights the necessity of integrating such systems with particle detector arrays to enhance event discrimination.
Copyright (c) 2025 Henry Mayorga, Alejandro Amagua Romero, Hugo Moreno Aviles https://creativecommons.org/licenses/by-nc/4.0
Characterization of HIV drug resistance profiles in patients at a healthcare center in Quito: “A pilot study”
HIV/AIDS is one of the most important chronic infectious diseases. Although ART therapies decreased morbidity and mortality considerably, new cases continue to appear. HIV-1 drug resistance is one of the most important problems that delay 95-95-95 goals. The presence of drug resistance mutations in naïve and ART-experienced patients is considered a risk factor for treatment failure and the transmission of HIV-1 resistance strains. A cross-sectional study included naïve and ART-experienced patients from one health care center in Quito-Ecuador in 2019 and 2021. Demographic data was collected with blood samples for sequencing, genotyping, and resistance tests. In 42 patients recruited, the overall prevalence of HIV-1 DRM was 9.5%, most related to NNRTI. A total of 42 mutations were found, 38.6% related to PIs, 34.09% to NNRTI/NRTIs, and 22.7% to INSTIs, most of them considered as minor or accessories, producing PLLR, LLR, and in one patient, HLR to NNRTIs. Although few drug resistance mutations that reduce ART susceptibility were identified, further studies are required to characterize HIV-1 drug resistance in Ecuador and its implications for clinical response.
Copyright (c) 2025 Paulina Quirola Amores, Pablo Espinosa, Nelson Cevallos, Enrique Teran https://creativecommons.org/licenses/by-nc/4.0
Biopolymers and Nanotechnology: eco-friendly and sustainable alternative in Enhanced Oil Recovery
Biopolymers, natural and biodegradable materials, emerge as a promising and sustainable alternative in the oil industry, optimizing oil extraction in a profitable and environmentally friendly way These biopolymers, capable of improving the mobility ratio, increasing viscosity, and decreasing permeability, are emerging as a critical trend in Enhanced Oil Recovery (EOR), with the potential to replace conventional synthetic polymers When selecting polymers for EOR, it is essential to consider factors such as cost, availability, and functional properties The methodology used in the research involved a systematic review of the scientific literature, encompassing a critical analysis of recent advances in biopolymer research for EOR The study also compares biopolymers and synthetic polymers, considering efficiency, cost, and environmental implications Additionally, the research explores the economic considerations associated with utilizing biopolymers in EOR, including cost factors and potential returns on investment Continuous innovation in using biopolymers is seen as the future of EOR, offering a more ecological and responsible alternative to exploit this important resource The choice of biopolymers contributes to a more sustainable and environmentally conscious oil industry.
Copyright (c) 2025 Edwars Naranjo, Inés Hernández Guerra, Lourdes Orejuela-Escobar https://creativecommons.org/licenses/by-nc/4.0
Photosynthetic organisms and water quality in Amazonian rivers, case study Yacuambi, Zamora Chinchipe
Mining and livestock activities in the Yacuambi canton significantly alter the ecological conditions of aquatic bodies, particularly rivers and water sources used for human consumption. This study evaluated water quality using methods based on bioindicators, specifically phytoplankton, as a complementary approach to physicochemical assessments. Phytoplankton play a crucial role in the structure and primary production of aquatic ecosystems; therefore, analyzing their composition and structure serves as a biological indicator of water quality. In situ water samples were collected for both physicochemical analysis (pH, dissolved oxygen, conductivity, total dissolved solids, temperature, nitrates, and phosphates) and biological analysis (diatoms). In the laboratory, microscopy and quantification of phytoplanktonic cells were conducted, enabling the application of an index to determine water quality. The application of the General Diatom Index (GDI) revealed significant differences in water quality (p < 0.05) among the Santa Inés stream and the Yacuambi and El Salado rivers. In terms of abundance, individuals from the genera Microspora, Ulothrix, Navicula, Gomphonema, and Ulnaria were recorded. Temperature, dissolved oxygen, and conductivity were the variables that most differentiated the studied rivers (p < 0.05). Multivariate analysis revealed the formation of specific groups for each river, including phytoplankton organisms that serve as indicators of water quality and physicochemical variables, which together explained at least 69 % of the data variability in all cases.
Copyright (c) 2025 Alonso Cartuche, Nikolay Aguirre, Roberth Yaguana , Roberto Bustillos, Vinicio Alvarado , Max Encalada , Josselyn Balcazar https://creativecommons.org/licenses/by-nc/4.0
Mechanical characterization of mode I fracture toughnessin multidirectional printed continuous fiber laminates.
The delamination failure mechanism between layers is one of the most critical in laminated fiber-reinforced polymer (FRP) composites, a phenomenon that has driven numerous research efforts. While a large body of literature focuses on this issue in unidirectional laminates, in-service conditions often lead to fracture initiation and propagation at interfaces with different fiber orientations. This study presents the experimental characterization of mode I fracture toughness in a continuous fiber composite manufactured through Additive Manufacturing (AM), defining configurations with multidirectional interfaces. The laminate design process for Double Cantilever Beam (DCB) specimens is detailed, ensuring stable and planar crack propagation. The proposed design methodology is validated through mechanical testing, employing laminate configurations that meet appropriate evaluation criteria. Fracture morphology of representative samples from each configuration is analyzed using Scanning Electron Microscopy (SEM), revealing similarities in surface features and specific failure mechanisms across the samples.
Copyright (c) 2025 Jonnathandario Santos, Luis Córdova Narváez, José Quichimbo https://creativecommons.org/licenses/by-nc/4.0
Unraveling the Water–Energy Nexus (WEN): A Structured Analytical Framework and a Six-Pillar Extended Definition for Governance and Future Research
This study synthesizes peer-reviewed journal articles indexed in the Web of Science Core Collection (2018–2023) to clarify how the water–energy nexus is framed, measured, and governed. We derive nine analytical dimensions from key nexus variables 1) sectoral composition & interactions, 2) resource inputs and outputs, 3) social actors, 4) methodological frameworks, 5) problems and limitations, 6) geographic distribution, 7) operational nexus definitions, 8) territorial scales, and 9) study type. This classification reveals three structural bottlenecks: (i) methodological concentration on static environmentally extended input–output models; (ii) regional aggregation of case studies in data‑rich China, which limits global transferability; and (iii) institutional narrowness, with multi-level governance and civil society underrepresented. Network analysis shows that conceptual framing predicts methodological choice and actor inclusion, and indicates limited methodological diversification —a relationship synthesized into the six pillars proposed below. Beyond existing WEN reviews, this combination of nine-dimension coding, cross-dimensional frequency analysis, and co-occurrence networks provides an empirical basis for the six pillars by linking how the nexus is defined to how it is measured and who is represented in the analysis. To support sustainable engineering decisions, we propose an extended water-energy nexus definition built around six interlocking pillars: high-resolution flow accounting; dynamic feedback modeling (rebound/tipping risks); explicit coupling with carbon, land, and waste; hybrid quantitative–qualitative analytics; inclusive multi-level collaborative governance; and interoperable open-data architectures. Together, these pillars translate fragmented case evidence into an engineering-ready, justice-sensitive systems framework, informing integrated water–energy infrastructure planning, evaluation of energy-transition pathways under water constraints, and prioritization of governance and data-architecture improvements required for interoperable nexus monitoring across sectors and scales.
Copyright (c) 2026 Eduardo Pérez-Denicia, Diana Rosa Pérez Serrano https://creativecommons.org/licenses/by-nc/4.0
The contribution of mutation induction to crop improvement: Addressing climate change and ensuring food security
For the genetic improvement of species of agricultural importance, it is essential to have a broad genetic base, ensuring sufficient variability to increase opportunities for selecting specific traits of interest in the field. Additionally, the use of techniques complementary to conventional breeding systems is crucial for effectively exploring the available genetic variability. Currently, there are several techniques, such as in vitro culture, genetic transformation, gene editing, marker-assisted selection, and mutation induction, among others. This review aims to synthesize the historical development, current applications, and future potential of mutation induction in crop improvement, with an emphasis on its role in adaptation to climate change and food security. Mutation induction techniques have played a key role in addressing challenges related to food security by promoting the development of new varieties for the agricultural sector in various countries. Through the analysis of the FAO/IAEA Mutant Varieties Database, it was possible to identify how mutation induction has contributed to the development of cultivars adapted to the specific needs of food security and climate. The FAO/IAEA program (https://nucleus.iaea.org), which promotes the use of nuclear techniques in agriculture, has resulted in the release of more than 3404 mutant varieties in 233 cultivated species in 75 countries. In several countries, as indicated in the MVD, the use of mutant germplasm in plant breeding programs has been crucial for adapting crops to new climatic conditions, in addition to meeting the growing demand for food. These advances highlight the potential of mutation induction as an essential tool to address future agricultural challenges, underlining the importance of continuing to invest in nuclear techniques for breeding cultivars adapted to climate change and global food security.
Copyright (c) 2025 Raymond Joseph, Viviane Kopp da Luz, Amanda Valentini Baseggio, Adriana Pires Soares Bresolin, Antonio Costa De Oliveira https://creativecommons.org/licenses/by-nc/4.0
Analysis of combined intracantonal public transportation at the Río Coca Terminal: A bibliographic review
This study examines the intra-cantonal transportation system that connects the Río Coca terminal in Quito with the rural parishes of the Tumbaco Zonal Administration, evaluating the factors that affect the mobility of users on long-distance trips from the urban hypercenter of Quito to rural areas. The urbanization dynamics reflected in the population growth rates of these areas are considered. To achieve this, a review of publications between 1990 to 2023 was made, in the Scopus, Web Of Science, and Google Scholar databases, in English, Spanish and French with key words indexed in the UNESCO Thesaurus dictionary. For the analysis, scientometric tools such as Posit Cloud, tree of Science (Tos), Bibliometrix, VOSviewer were used and the inclusion criteria were the population rates between 1990 and 2001, which were significantly high in parishes such as Pifo (5.92 %), Puembo (5.25 %), Yaruquí (5.49 %), Checa (5.89 %) and El Quinche (5.93 %). Additionally, between 2001 and 2010, growth was recorded in Cumbayá (4.45 %). The economic activity of the users was also taken into account. Data such as education, language and race were excluded. Based on this analysis, a model of growth in transport demand was developed, allowing the identification of routes that require the expansion of service areas, as well as current and future congestion points.
Copyright (c) 2025 Alisson Dayana Alvarez Fueres, Gabriela Muñoz, Fausto Alejandro Rodríguez Bravo, Mónica Susana Delgado Yánez https://creativecommons.org/licenses/by-nc/4.0
First predation record of the Galapagos Hawk Buteo galapagoensis (Accipitriformes: Accipitridae), on a feral cat Felis catus (Carnivora: Felidae)
The Galápagos hawk Buteo galapagoensis is the top predator of the archipelago, feeding on a wide variety of species from different taxonomic groups, ranging from insects to carrion. We report the first recorded instance of predation by a Galápagos hawk on a feral cat Felis catus, as camera trap bycatch, on Wolf Volcano, Isabela Island. This report adds to the extensive list of the hawk’s dietary items and may have ecological implications, such as the role of introduced species in food webs, the role of native predators in controlling invasive species, and how these interactions play out on islands, leaving many open questions.
Copyright (c) 2025 Elias Viteri-Basso, Johannes Ramirez Kastdalen, Jorge Carrión-Tacuri https://creativecommons.org/licenses/by-nc/4.0
Optimization of sourness and flavor in orange-flavored gummy candies using a simplex-lattice mixture design implemented with R
Acidulants are crucial for enhancing and balancing the flavor profiles of confectionery products, such as gummy candies, ensuring an optimal sensory experience. This study aimed to develop an R script using the simplex-lattice mixture design to optimize the sourness and flavor levels and the combined response of these attributes for orangeflavored gummy candies, demonstrating its application in improving the sensory qualities of confectionery products. The gummy candies were prepared according to previous research, incorporating citric, malic, and fumaric acids based on the experimental design. The R scripts were provided and uploaded to the GitLab platform for download and analysis (https://gitlab.com/FoodChem-DataSci-Lab/orange-flavored-gummy-candies). The effects of these acids on sourness and flavor were assessed using a 5-point hedonic scale by 30 trained judges. The data were analyzed with R, resulting in mathematical models for the acids’ individual effects, interactions, and combined responses. Effect (Piepel direction) and contour plots were generated as well. The optimal mixture was determined to be 4.95 g of citric acid, 4.65 g of malic acid, and 5.40 g of fumaric acid, achieving an optimal combined response value of 107.14. In conclusion, balancing these three acids is critical to optimizing sourness and flavor levels in orange-flavored gummy candies. This study provided a valuable methodology for formulating confectionery products with enhanced sensory profiles. It demonstrated the capability of R to address complex problems in both the confectionery industry and academia, emphasizing its importance as an analytical tool for developing products with improved sensory characteristics.
Copyright (c) 2025 Lizbeth Chávez-Reyes, Laura García-Curiel, Jesús Guadalupe Pérez Flores, Emmanuel Pérez-Escalante, Elizabeth Contreras-López, Lizbeth Anahí Portillo-Torres, Luis Guillermo González-Olivares, Carlos Ángel-Jijón https://creativecommons.org/licenses/by-nc/4.0
An Act of Resistance: The Role of Local Journals
Copyright (c) 2025 Mateo Dávila-Játiva https://creativecommons.org/licenses/by-nc/4.0
Rehabilitation and reinforcement of heritage structures built with rammed earth in Ecuador to restore structural and mechanical characteristics
In Ecuador, it has been observed that heritage built with rammed earth has suffered advanced deterioration due to the passage of time and environmental, biotic, intrinsic, and anthropological factors. Their preservation and conservation are important due to its high cultural and historical value. The objective of this research is to determine rehabilitation and reinforcement methods applicable to this type of structure, aimed at recovering the structural and mechanical characteristics of earthen elements. A bibliographic review was carried out to determine the optimal mixture for rammed earth mixture, as well as the types of reinforcement that could be applied, considering both natural materials (bamboo) and synthetic materials (polypropylene mesh). Based on international testing standards for earthen walls, tests were conducted to verify the resistance and effectiveness of the proposed techniques. It was determined that the reinforcement method using a guadua cane framework has allowed for the recovery and increase of approximately 5 % in tensile strength and 61 % in compressive strength.
Copyright (c) 2026 Vanessa Colcha, Luz América Juinia Juiña, Paulina Viera https://creativecommons.org/licenses/by-nc/4.0
Effect of corn and cassava silage on the economic and productive performance of hair creole sheep (Ovis aries)
This study evaluated the productive performance and economic viability of supplementing Creole sheep with corn and cassava forage silage. Twelve males (17.6 ± 3.2 kg live weight and 8 months old) were selected and randomized into two groups, one supplemented with corn silage (D1EM) and another with mixed of corn and cassava silage (D2EM+EY) in equal proportions. The animals were evaluated for 52 days (10 days of adaptation) during the dry period. Productive performance in weight gain, body corporal condition, silage intake, and ocular conjunctiva coloration were recorded; information on costs and income was also collected. The productive data was analyzed considering a T-test for independent samples. The D2EM+EY increased (p<0.05) daily gain (0.080 ± 0.01 kg/d vs. 0.060 ± 0.01 kg/d) and accumulated weight in the evaluation period (3.33 ± 0.58 kg vs. 2.45 ± 0.43 kg), and decreased feed conversion (kg: kg, 6.01:1 vs. 8.27:1); also, was observed better ocular conjunctiva condition (Famacha® 2 vs. 1). D2EM+EY supplementation presented a benefit-cost ratio of 2.4 and profitability of 72%, with a production cost of US$ 0.93 per kg of live weight. The strategic supplementation with corn and cassava silage increased weight gain and maintained the animals' body condition during drought, with higher income than production costs.
Copyright (c) 2025 Liliana Atencio Solano, Emiro Suarez Paternina, José Jaime Tapia Coronado, Yacerney Paternina Paternina, Wilson Barragan Hernández, Lorena Mestra Vargas https://creativecommons.org/licenses/by-nc/4.0
PoI+NBU: A Feasibility study in Generating High-Resolution Adversarial Images with a Black Box Evolutional Algorithm based Attack
Adversarial attacks in the digital image domain pose significant challenges to the robustness of machine learning models. Trained convolutional neural networks (CNNs) are among the leading tools used for the automatic classification of images. They are nevertheless exposed to attacks: Given an input clean image classified by a CNN in a category, carefully designed adversarial images may lead CNNs to erroneous classifications, although humans would still classify "correctly" the constructed adversarial images in the same category as the input image. In this feasibility study, we propose a novel approach to enhance adversarial attacks by incorporating a pixel of interest detection mechanism. Our method involves utilizing the BagNet model to identify the most relevant pixels, allowing the attack to focus exclusively on these pixels and thereby speeding up the process of adversarial attack generation. These attacks are executed in the low-resolution domain, and then the Noise Blowing-Up (NBU) strategy transforms the low-resolution adversarial images into high-resolution adversarial images. The PoI+NBU strategy is tested on an evolutionary-based black-box targeted attack against MobileNet trained on ImageNet using 100 clean images. We observed that this approach increased the speed of the attack by approximately 65%.
Copyright (c) 2025 Enea Mancellari, Ali Osman Topal, Franck Leprévost https://creativecommons.org/licenses/by-nc/4.0