University Foundation Los Libertadores

The measurement of competitiveness requires the consideration of factors specific to a region or country. This article addresses the identification of a basic set of factors that, in comparison with European countries, impact the competitiveness of Latin American countries. A retrospective nonexperimental design was carried out by conducting non‐parametric correlation analysis, testing subsequently with multiple linear regression analysis, as well as structural equation analysis. Next, different predictive models were considered, and the four main variables explaining competitiveness in Europe and Latin America were identified from the Global Competitiveness Report. The selected independent variables were: incidence of corruption, buyers sophistication, pay‐productivity ratio, and investment in research and development. The analyzed models satisfactorily met the assumptions and showed an adequate fit. Two models are reported which synthesize relevant factors explaining the competitiveness of the analyzed countries, favoring a parsimonious approach to the explanation of this variable.

This research aims to present an analysis of the behavior of multiple Remotely Piloted Aircraft Systems (multi-RPAS) flying in formation, a key aspect of advanced aerial mobility in the aerospace industry. This involves the positioning and relative distance in three dimensions (3D) of two RPAS, taking into account their operational requirements and limitations, recognizing the operating states, and addressing potential situations encountered during formation flight. For this study, the “Conformance and Fault Injection—CoFI” methodology is employed. This methodology guides the user towards a comprehensive understanding of the system and enables the creation of a set of finite state machines representing the system’s behavior under study. Consequently, models and requirements for the behavior of multi-RPAS flying in formation are presented. By applying the CoFI methodology to inject faults into the operation and predict behavior in anomalous situations, both normal and abnormal behavior models, as well as the flight behavior requirements of the multi-RPAS formation, are outlined. This analysis is expected to facilitate the identification of formation flight behavior in multi-RPAS, thereby reducing associated operational risks.

Drilling fluids are essential for maintaining cutting suspension during drilling, exhibiting gel-like behavior at rest and liquid-like behavior under shearing. These fluids display shear-thinning behavior, yield stress, and thixotropy. This study investigates the impact of aging time on stress overshoot and the deformation required to disrupt the gelled structure of water-based and synthetic-based drilling fluids. Flow start-up tests were conducted using a rotational rheometer at 25 °C and atmospheric pressure. The results show that aging time significantly affects both stress overshoot and the shear strain needed to disrupt the gelled structure. Longer aging times reduce the strain required to break the structure, indicating a correlation between aging time and stress overshoot. The fitted model strongly correlates with the experimental data, providing valuable insights for the planning and simulation of offshore drilling wells, primarily in well stability.

This work investigates the impact of Mn and Co doping on the structural, morphological, electrical, and magnetic properties of ZnO thin films deposited via DC magnetron co-sputtering. Doping concentration, substrate temperature, and substrate type (soda-lime glass and oriented silicon wafer) were systematically varied for potential spintronic applications. X-ray diffraction (XRD) and Raman spectroscopy confirmed the formation of a hexagonal wurtzite crystalline structure with a preferential [002] growth orientation when Mn was incorporated into the ZnO matrix. Raman analysis also ruled out the presence of secondary Co oxide phases in ZnO:Co samples. Films doped with Mn at 25 W exhibited compressive stress of −0.345 %, which increased to −2.03 % at 50 W, highlighting the dopant's impact on lattice strain. FTIR spectra revealed characteristic bands of ZnO:Co, indicating successful incorporation of Co ions into the matrix. SEM and magnetic force microscopy (MFM) showed granular surface morphology and cluster formation at higher Mn concentrations (50 W). Electrical measurements revealed unipolar and bipolar resistive switching (RS) behaviors, associated with the Schottky barrier model, and strongly influenced by substrate temperature and doping levels. Notably, samples doped with Co at 50 W exhibited enhanced interfacial RS properties. Vibrating sample magnetometry (VSM) demonstrated room-temperature ferromagnetic hysteresis in films synthesized at Ts = 423 K, with Mn (25 W) and Co (50 W) doping. These findings validate the potential of ZnO:Mn/Co as a dilute magnetic semiconductor (DMS) for spintronic applications, offering tailored magnetic and resistive properties through precise control of doping and synthesis parameters.

The use of biopolymers like Xanthan Gum (XG) for soil stabilization offers an eco-friendly alternative, enhancing soil properties while reducing CO2 emissions, gaining attention in sustainable engineering. This study investigated the interaction and geotech-nical improvements of clay mixed with XG and polypropylene fibers (PPF). Biopolymer was used in proportions of 1%, 3%, and 5%, while the PPF percentage was kept constant at 0.5% by weight. Additionally, the molding density was varied at 1.65 g/cm³, 1.70 g/cm³, and 1.76 g/cm³. A total of 108 specimens were prepared using two curing times (28 and 90 days), and the samples were subjected to unconfined compressive strength (UCS) tests, ultrasonic pulse velocity (UPV), and Scanning Electron Microscopy (SEM). The results demonstrate that the addition of XG and PPF in the specified proportions provides significant mechanical improvements to the stabilized soil. The curing time had a notable impact on these improvements; a curing time of 90 days resulted in strength increases of up to 37% compared to 28 days, while the maximum dry density improved this property by up to 87% compared to the minimum density. The incorporation of PPF enhanced strength by 53.93%, while stiffness increased by 63.55%. Additionally, the strength q u) and stiffness () results were successfully correlated using the porosity/binder index ⁄ , achieving determination coefficients (R²) greater than 0.90 and 0.80, respectively.

Artificial sand cementation improves stability, stiffness, and mechanical strength, making it a critical process in geotechnical applications. This study analyzes the capability of the porosity–water/binding agent index (ηCw/Biv) to predict cemented sands’ unconfined compressive strength (qu) and stiffness (Go). Four Colombian sands, i.e., Luruaco, Medellín, Lorica, and Bogotá (stabilized with Portland cement), and were compared with three Brazilian sands: i.e., Osorio, Porto Alegre, and Rio Pardo were evaluated, stabilized with combinations of carbide lime and glass powder, using varying binder contents and a curing period of seven days subjected to ultrasonic pulse velocity (UPV) tests and unconfined compressive strength (UCS) tests. The results indicate that incorporating water content into the index significantly enhances predictive accuracy, achieving R2 values above 0.94 for Colombian sands and considerably better fits for Brazilian sands than the traditional porosity/binder index. This new alternative provides an appropriate parameter for representing the small-strain stiffness and unconfined compressive strength of artificially cemented sands stabilized with various types of binders. Furthermore, the new index proved to be more effective in predicting the behavior of uniform and loose-graded sands, such as those from Bogotá and Lorica, which rely more heavily on binder volume and water content to achieve greater strength and stiffness. Lastly, the predictive model, validated against experimental results, achieved reliability indices (R2) of 0.9791 for stiffness and 0.9799 for strength prediction.

This article discusses the dynamics of innovation in America and Europe, focusing on variables such as access to technology, education, and life expectancy. To do this, the article proposes an agent-based model called the Innovameter. The dependent variable is the Global Innovation Index. The paper focuses on data analysis through correlation analysis and multiple hierarchical regressions to determine the contribution of specific variables related to the pillars of the Global Innovation Index and indicators of the Human Development Index. After analyzing the data, an agent-based model was built to parameterize these main variables by defining two levels of abstraction: at the global level, there is the country, where birth rates, life expectancy, ICT use, and research and development are defined. At the local level, we define the individuals who have an age, years of schooling, and income. A series of experiments were conducted by selecting data from 30 countries. From the results of the experiments, a nonparametric correlation analysis was performed, and correlation indices were obtained indicating a relationship between the predicted outcomes and the outcomes in the global index. The proposed model aims to provide suggestions on how the different variables can become the norm in most of the countries studied.

Background/Objectives: Non-fermenting Gram-negative bacteria are resistant to most antibiotics, due to the production of enzymes such as NDM-1. Faced with this challenge, computational methods have become essential for the design of NDM-1 carbapenemase inhibitors, optimizing both the time and cost of the development of new lead molecules. Methods: In this study, molecular docking and molecular dynamics (MD) simulations were performed in order to identify effective inhibitors against the NDM-1 enzyme. Protein preparation was carried out using UCSF Chimera and AutoDockTools 1.5.7, while ligands were prepared with MarvinSketch, Avogadro, and AutoDockTools 1.5.7. Molecular docking was run with AutoDock4 and AutoDock4Zn, determining that molecules M26 (−13.23 kcal/mol with AutoDock4 and −13.11 kcal/mol with AutoDockZn) and M25 (−10.61 kcal/mol with AutoDock4 and −11.18 kcal/mol with AutoDockZn) presented the best binding energy affinities with NDM-1. The M26 molecule formed six hydrogen bonds with the enzyme. Results: MD simulations, performed with GROMACS, indicated that the NDM-1-M26, NDM-1-M35, and NDM-1-M37 complexes showed conformational stability and flexibility. Conclusions: These results suggest that the M26, M37, and M35 ligands have significant potential as leading candidates in the development of new NDM-1 inhibitors, outperforming the antibiotic Meropenem in some respects.

The Cooper-pair distribution function Dcp(ω,Tc) of Untwisted-Misaligned Bilayer Graphene (UMBLG) in the presence of an external electric field is calculated and analysed within the framework of first-principle calculations. A bilayer graphene structure is proposed using a structural geometric approximation, enabling the simulation of a structure rotated at a small angle, avoiding a supercell calculation. The Dcp(ω,Tc) function of UMBLG indicates the presence of the superconducting state for specific structural configurations, which is consistent with the superconductivity in Twisted Bilayer Graphene (TBLG) reported in the literature. The Dcp(ω,Tc) function of UMBLG suggests that Cooper-pairs are possible in the low-frequency vibration region. Furthermore, the structural geometric approximation allowed the evaluation of the effect of the electric field on the superconducting state of UMBLG and its superconducting critical temperature through the Ncp parameter.

Due to the lucrative coffee market, this product is often subject to adulteration, as inferior or non-coffee materials or varieties are mixed in, negatively affecting its quality. Traditional sensory evaluations by expert tasters and chemical analysis methods, although effective, are time-consuming, costly, and require skilled personnel. The aim of this work was to evaluate the capacity of a smart electronic tongue (e-tongue) based on a polypyrrole sensor array as a tool for the rapid analysis of coffees elaborated from beans of different varieties. The smart e-tongue device was developed with a polypyrrole-based voltammetric sensor array and portable multi-potentiostat operated via smartphone. The sensor array comprised seven electrodes, each doped with distinct counterions to enhance cross-selectivity. The smart e-tongue was tested on five Arabica coffee varieties (Typica, Bourbon, Maragogype, Tabi, and Caturra). The resulting voltammetric signals were analyzed using principal component analysis assisted by neural networks (PCNN) and cluster analysis (CA), enabling clear discrimination among the coffee samples. The results demonstrate that the polypyrrole sensors can generate distinct electrochemical patterns, serving as “fingerprints” for each coffee variety. This study highlights the potential of polypyrrole-based smart e-tongues as a rapid, cost-effective, and portable alternative for coffee quality assessment and adulteration detection, with broader applications in the food and beverage industry.

We incorporate non-Markovian profiles and Linear Response Theory to analyze memory effects in two-band topological quantum systems. Furthermore, we have applied a measure of non-Markovianity in terms of nonlinear optical spectroscopy. On the other hand, we resort to memory kernel, solve the integro-differential equation of the open two-band topological quantum system to describe the degrees of non-Markovianity, calculate response factors based on Linear Response Theory, and analyze non-Markovian dynamics by varying the parameters of the nonlinear spectroscopy environment of the respective open quantum system.

Research from around the world highlights the importance of creating affordable and simple industrial wastewater treatment systems to preserve water resources. The absence of such systems can have serious consequences. For example, the release of chromium (VI) from industries such as tanneries pollutes water bodies, often causing irreversible damage. The mechanical properties, low acquisition cost, and abundance of aquatic plant biomass of E crassipes make it a viable option for Cr (VI) removal. Furthermore, the addition of TiO 2 to plant biomass increases the amount of functional groups that contribute to high removal of heavy metals, including Cr (VI), providing an economical and efficient material for a novel industrial water treatment. The objective of this study is to create water treatment systems using TiO 2 treated E crassipes root waste powder. Removal data were collected from two fixed bed columns operating in series, treating about 4 L of water, removing 99% of the Cr (VI) present. Design parameters for a larger scale treatment system were modeled and validated using internal and external particle and mass balance models. Column reusability was evaluated by EDTA elution studies, adding all cycles, the total adsorption capacity was 69 mg/g. A full-scale treatment system was designed and developed using these models under effluent conditions similar to those found in the tanning and painting industries. The strategy proposed in this work allows compliance with environmental regulations through the use of green biotechnologies and mathematical and statistical reliability models. This tool is of vital importance in the concept of circular economy. Graphical abstract

The search for adsorbents that are non-toxic and low cost with a high adsorption capacity and excellent recyclability is a priority to determine the way to reduce the serious environmental impacts caused by the discharge of effluents loaded with heavy metals. Bacterial cellulose (BC) biomass has functional groups such as hydroxyl and carbonyl groups that play a crucial role in making this cellulose so efficient at removing contaminants present in water through cation exchange. This research aims to develop an experimental process for the adsorption, elution, and reuse of bacterial cellulose biomass in treating water contaminated with Cr (VI). SEM images and the kinetics behavior were analyzed with pseudo-first- and pseudo-second-order models together with isothermal analysis after each elution and reuse process. The adsorption behavior was in excellent agreement with the Langmuir model along with its elution and reuse; the adsorption capacity was up to 225 mg/g, adding all the elution processes. This study presents a novel approach to the preparation of biomass capable of retaining Cr (VI) with an excellent adsorption capacity and high stability. This method eliminates the need for chemical agents, which would otherwise be difficult to implement due to their costs. The viability of this approach for the field of industrial wastewater treatment is demonstrated.

The particular properties of graphene oxide (GO) make it a material with great technological potential, so it is of great interest to find renewable and eco-friendly sources to satisfy its future demand sustainably. Recently, agricultural waste has been identified as a potential raw material source for producing carbonaceous materials. This study explores the potential of cashew nut shell (CNS), a typically discarded by-product, as a renewable source for graphene oxide synthesis. Initially, deoiled cashew nut shells (DCNS) were submitted to pyrolysis to produce a carbonaceous material (Py-DCNS), with process optimization conducted through response surface methodology. Optimal conditions were identified as a pyrolysis temperature of 950 °C and a time of 1.8 h, yielding 29.09% Py-DCNS with an estimated purity of 82.55%, which increased to 91.9% post-washing. Using a modified Hummers method, the Py-DCNS was subsequently transformed into graphene oxide (GO-DCNS). Structural and functional analyses were carried out using FTIR spectroscopy, revealing the successful generation of GO-DCNS with characteristic oxygen-containing functional groups. Raman spectroscopy confirmed the formation of defects and layer separations in GO-DCNS compared to Py-DCNS, indicative of effective oxidation. The thermogravimetric analysis demonstrated distinct thermal decomposition stages for GO-DCNS, aligning with the expected behavior for graphene oxide. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) further corroborated the morphological and compositional transformation from DCNS to GO-DCNS, showcasing reduced particle size, increased porosity, and significant oxygen functional groups. The results underscore the viability of cashew nut shells as a sustainable precursor for graphene oxide production, offering an environmentally friendly alternative to conventional methods. This innovative approach addresses the waste management issue associated with cashew nut shells and contributes to developing high-value carbon materials with broad technological applications.

Ag2CrO4 is a representative member of a family of Ag-containing semiconductors with highly efficient visible-light-driven responsive photocatalysts. The doping process with Eu³⁺ is known to effectively tune their properties, thus opening opportunities for investigations and application. Here, we report the enhancement of the photocatalytic activity and stability of Ag2CrO4 by introducing Eu³⁺cations. The structural, electronic, and photocatalytic properties of Ag2CrO4:xEu³⁺ (x = 0, 0.25, 0.5, 1%) synthesized using the coprecipitation method were systematically discussed, and their photodegradation activity against rhodamine B (RhB), ciprofloxacin hydrochloride monohydrate (CIP), and 4-nitrophenol (4-NP) was evaluated. Structural analyses reveal a short-range symmetry breaking in the Ag2CrO4 lattice after Eu³⁺ doping, influencing the material morphology, size, and electronic properties. XPS analysis confirmed the incorporation of Eu³⁺ and alteration of the surface oxygen species. Furthermore, photoluminescence measurements indicated that the doping process was responsible for reducing recombination processes. The sample doped with 0.25% Eu³⁺ exhibited superior photocatalytic performance compared to pure Ag2CrO4. Scavenger experiments revealed an increase in the degradation via •OH reactive species for the sample doped with 0.25% Eu³⁺. DFT calculations provided atomic-scale insights into the structural and electronic changes induced by the Eu³⁺ doping process in the Ag2CrO4 host lattice. This study confirms that Eu³⁺ doping alters the band structure, enabling different degradation paths and boosting the separation/transfer of photogenerated charges, thereby improving the overall photocatalytic performance.

Cassava starch solid biopolymer electrolyte (SBPE) films were prepared by a thermochemical method with different concentrations of lithium triflate (LiTFT) as a dopant salt. The process began with dispersing cassava starch in water, followed by heating to facilitate gelatinization; subsequently, plasticizers and LiTFT were added at differing concentrations. The infrared spectroscopy analysis (FTIR-ATR) showed variations in the wavenumber of some characteristic bands of starch, thus evidencing the interaction between the LiTFT salt and biopolymeric matrix. The short-range crystallinity index, determined by the ratio of COH to COC bands, exhibited the highest crystallinity in the salt-free SBPEs and the lowest in the SBPEs with a concentration ratio (Xm) of 0.17. The thermogravimetric analysis demonstrated that the salt addition increased the dehydration process temperature by 5 °C. Additionally, the thermal decomposition processes were shown at lower temperatures after the addition of the LiTFT salt into the SBPEs. The differential scanning calorimetry showed that the addition of the salt affected the endothermic process related to the degradation of the packing of the starch molecules, which occurred at 70 °C in the salt-free SBPEs and at lower temperatures (2 or 3 °C less) in the films that contained the LiTFT salt at different concentrations. The cyclic voltammetry analysis of the SBPE films identified the redox processes of the glucose units in all the samples, with observed differences in peak potentials (Ep) and peak currents (Ip) across various salt concentrations. Electrochemical impedance spectroscopy was used to establish the equivalent circuit model Rf–(Cdl/(Rct–(CPE/Rre))) and determine the electrochemical parameters, revealing a higher conduction value of 2.72 × 10−3 S cm−1 for the SBPEs with Xm = 17 and a lower conduction of 5.80 × 10−4 S cm−1 in the salt-free SBPEs. It was concluded that the concentration of LiTFT salt in the cassava starch SBPE films influences their morphology and slightly reduces their thermal stability. Furthermore, the electrochemical behavior is affected in terms of variations in the redox potentials of the glucose units of the biopolymer and in their ionic conductivity.