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Rate-dependency of residual shear strength of soils: implications for landslide evolution
No full textShear-rate weakening or strengthening behaviours can effectively control landslide runouts, defining sudden runaway sliding or years-long slow-creep phases. These behaviours are partly controlled by the properties of the basal material. Understanding its stress–strain–time response is crucial in physically-based assessments of landslide dynamics and the associated risk. We investigate the frictional resistance of a calcium bentonite, a kaolin and a quartz sand by means of a conventional ring-shear apparatus under normal stresses representative of landslide shear zones. Results for the fine-grained soils, in line with literature on pure clays, indicate important velocity strengthening, whereas small shear-rate effects were observed in sand. As long as effective stresses remain constant, a velocity strengthening response can exert a feedback that, under certain conditions, counteracts perturbations in boundary conditions and prevents fast runouts on pre-existing shear zones. Accordingly, we argue that specifically testing for shear-rate-dependency and incorporating observed behaviours in model formulations can be beneficial for better predicting landslide fates
Preparation of carbonaceous materials from flotation-sludge of the poultry industry and its application in the methylene blue adsorption
No full textIn this work, different carbonaceous materials based on floated sludge from a poultry industry wastewater treatment plant (PI-WTP) were synthesized. These materials were characterized and investigated in methylene blue dye (MB) adsorption. The influences of the initial pH solution, adsorbent dosage, kinetics, equilibrium, and thermodynamics were evaluated in the adsorption experiments. A simulation of a real textile effluent was also carried out to evaluate the adsorbent. The results of the adsorbents’ characterization demonstrated that adding ZnCl2 + lime, followed by pyrolysis and acid leaching, significantly improved the material’s properties, leading to abundant porosity and high surface area. The adsorption experiments indicated that the natural pH of the solution (8.0) and the AC-II dosage of 0.75 g L−1 are optimal for MB removal. Elovich and Sips’ models (with a maximum adsorption capacity of 221.02 mg g−1 at 328 K) best fitted the experimental kinetic and equilibrium data, respectively. The adsorption process is spontaneous and endothermic according to thermodynamic parameters. The discoloration efficiency of the simulated effluent was 67.8%. In conclusion, the floated sludge, a residue produced on a large scale that needs to be disposed of correctly, can be converted into a value-added material (carbonaceous adsorbent) and applied to treat colored effluents
Effects of wavy structure, ambient conditions and solar intensities on flow and temperature distributions in a mini solar flat plate collector using computational fluid dynamics
No full textMini solar flat plate collectors have gained traction due to their cost-effectiveness, high efficiency in converting solar radiation to heat energy, and versatility in residential and commercial applications, offering long lifespans with minimal maintenance. Optimizing the thermal performance of solar flat plate collectors using numerical simulations helps enhance their efficiency, making them even more appealing for small-scale heating and hot water applications. This study investigates the flow behavior and temperature distribution of air within a small-sized solar collector (286 × 800 × 70 mm) and optimizes its design for achieving the highest outlet air temperature. The optimization process included varying geometric parameters, such as the wavy structure hole diameter, and considering a range of operating conditions, including ambient conditions and solar intensities. This analysis aimed to understand the flow behavior and temperature distributions within the solar collector. The numerical studies provided valuable insights into the thermal and flow characteristics of the collector. The velocity distribution of the fluid within the collector aided in understanding the flow behavior, optimizing the flow path to minimize pressure drop, and maximizing heat transfer. Additionally, calculations were performed to determine total useful heat, outlet temperatures, and efficiencies. The study also discusses the optimal design and operating conditions for the collector
Evidentiary value of the electronic document in the administrative sanctioning procedure in Chile
No full textEl objetivo es analizar el sistema probatorio aplicable a la valoración de la prueba documental electrónica en un procedimiento administrativo sancionador de tipo desformalizado en Chile. La investigación se desarrolla con base en una metodología dogmática a partir del análisis e interpretación de la información obtenida por técnicas documentales. El artículo se sustenta tanto en la doctrina ius puniendi administrativa, como en los principios básicos de los sistemas del Derecho Probatorio, desde una visión panorámica cimentada, fundamentalmente en la Teoría del Derecho, para sostener que el estándar probatorio señalado debe ser el de la prueba tasada. Los resultados permiten establecer que, a falta de regulación sectorial, debe aplicarse el artículo 5° de la Ley N° 19.799 con preferencia del artículo 35 inciso 1° de la Ley N° 19.880, lo cual conlleva que en los procedimientos administrativos sancionatorios que carezcan de norma especial, el documento público electrónico tiene el valor de plena prueba en los términos que indica el Código Civil, pero restringida, exclusivamente, a los hechos que precisa el mencionado Código.The objective is to analyze the evidentiary system applicable to the valuation of electronic documentary evidence in a non-formalized administrative sanctioning procedure in Chile. The research is developed based on a dogmatic methodology from the analysis and interpretation of the information obtained by documentary techniques. The article is based on the administrative ius puniendi doctrine, as well as on the basic principles of the systems of Probative Law, from a panoramic vision based, fundamentally, on the Theory of Law, to sustain that the evidential standard indicated must be the one of the assessed proofs. The results allow us to in the absence of sectorial regulation, Article 5 of Law No. 19,799 should be applied in preference to Article 35, paragraph 1 of Law No. 19,880, which means that in administrative sanctioning procedures lacking a special rule, the electronic public document has the value of full proof in the terms indicated in the Civil Code but restricted exclusively to the facts specified in the Civil Cod
Evaluating the impact of simulation-based instruction on critical thinking in the Colombian Caribbean: an experimental study
No full textThis research aimed to investigate the impact of Simulation-Based Learning (SBL), specifically within the Model United Nations (MUN) framework, on enhancing critical thinking and improving academic performance in a sample of 42 undergraduate students studying International Relations at a university in Northern Colombia. The objectives were to measure the students’ attitudes towards SBL and its impact on their academic achievement in two Economic Development courses. A Student’s t-test was applied to compare the effectiveness of SBL with traditional instruction, and performance values were analyzed using minimum, maximum, and average statistics. The focus was on how effectively SBL encouraged an inquiry-based approach in students and their understanding of a country’s objectives, and how this translated into their academic success. The results indicated that the implementation of simulations significantly boosted the students’ understanding, thereby leading to improved learning outcomes. These findings suggest that SBL within the Model of United Nations (MUN) framework can be an effective tool in fostering critical thinking and enhancing academic performance among International Relations students
Environment and Armed Conflict: Perspectives of Former Combatants of the Revolutionary Armed Forces of Colombia (FARC)
No full textColombia es sede del conflicto armado más largo de la historia. Esta situación ha tenido repercusiones negativas en diversos aspectos sociales, económicos, políticos y ambientales. Específicamente, este estudio tuvo como objetivo analizar las consecuencias ambientales del conflicto armado en Colombia a través de la interpretación de nociones generales sobre el conflicto y su vínculo con la degradación ambiental. Para llevar a cabo esta tarea, se realizó una exploración del contexto, incluyendo las características generales del territorio que contribuyeron al surgimiento del conflicto, los daños ambientales causados durante la guerra y los principales actores involucrados en la degradación del territorio, en función de sobre las percepciones, opiniones, experiencias y sentimientos de los excombatientes. La información se recopiló a través de entrevistas en profundidad. Los resultados se centraron en comprender los elementos significativos del vínculo entre la situación ambiental y el período posterior al acuerdo de paz. Este estudio invita a reflexionar sobre las implicaciones indirectas de la guerra y proporciona valiosos conocimientos para el diseño e implementación de políticas públicas destinadas a prevenir el deterioro ambiental, promover la reconciliación y mejorar las condiciones de vida de la población afectada.Colombia is home to the longest-running armed conflict in history. This situation has had negative repercussions on various social, economic, political, and environmental aspects. Specifically, this study aimed to analyze the environmental consequences of the armed conflict in Colombia through the interpretation of general notions about the conflict and its link to environmental degradation. To accomplish this task, an exploration of the context was conducted, including the general characteristics of the territory that contributed to the emergence of the conflict, the environmental damages caused during the war, and the main actors involved in the degradation of the territory, based on the perceptions, opinions, experiences, and feelings of former combatants. Information was collected through in-depth interviews. The results focused on understanding the significant elements of the link between the environmental situation and the post-peace agreement period. This study prompts reflection on the indirect implications of war and provides valuable insights for the design and implementation of public policies aimed at preventing environmental deterioration, promoting reconciliation, and improving the living conditions of the affected population
DFT based kinetic Monte Carlo study of metal surface growth: comparison of a restricted and an unrestricted diffusion model
No full textThe growth behavior of Cr and W surfaces using kinetic Monte Carlo (KMC) simulations based on Density-Functional Theory (DFT) is presented in this study. Three models, a growth model with random deposition and no diffusion, a growth model with restricted diffusion and a growth model with unrestricted diffusion model, were compared to understand their influence on the predicted surface roughness and layer density. The impact of deposition rate and temperature on surface growth for both metals were analyzed. For deposition rate studies, five different rates (0.01 ML/s, 0.1 ML/s, 1.0 ML/s, 10.0 ML/s, and 100 ML/s) were considered at 550 K for Cr and W respectively. The effect of temperature on roughness was also studied employing various temperatures from 300 K to 1100 K for both metals and under the two different evolution models. The results show that the unrestricted diffusion model exhibits higher roughness compared to the restricted model for both metals. The restricted model shows a stable region of roughness, whereas the unrestricted model shows a continuous increase in roughness throughout the simulation. Furthermore, layer density analysis revealed that temperature affects the filling of lower monolayers. Finally, dynamic exponents β and α for each studied model were calculated and discussed. The results highlight the influence of diffusion models, deposition rate and temperature on surface, roughness, and layer density
Interaction of teaching styles with learning styles in university students: Case of Universidad de la Costa – Colombia
No full textThe objective of the study is to determine the relationship between teaching styles and learning styles in university students; through a correlational study, in a population of 40 professors and 170 university students (Case of Universidad de la Costa – Colombia). For learning styles, Kolb's learning styles instrument was used; and for teaching styles, the Teaching Styles Questionnaire was used, a standardized test designed under the methodology of the Evidence-Based Model and oriented to monitor the development of critical reading, written communication, citizenship competencies, quantitative reasoning and English. The resulting data were organized in a spreadsheet and processed using Statgraphics and R. The results show that the gender of the participants is not significant in the study; the predominant learning style of the students is the Accommodator, which is characterized by a better performance in concrete experience and active experimentation. As for the correspondence between learning styles and teaching styles, there is a strong relationship between them
Countering Global Extremism and Terrorism: the Role of International Organizations
No full textEl objetivo del artículo es identificar las principales direcciones de las actividades de las organizaciones (la ONU, la Unión Europea, la Liga de Estados Árabes (LEA) y la Organización de Cooperación Islámica (OCI)) dirigidas a reducir el proceso de radicalización, influyendo en el desarrollo del extremismo y el terrorismo. Para alcanzar el objetivo fijado, el método del estudio ha sido el análisis documental. Se han resumido los diferentes conceptos y modelos de radicalización, se ha sistematizado el marco normativo que aborda las actividades de las organizaciones (la ONU, la Unión Europea, la Liga de Estados Árabes (LEA) y la Organización de Cooperación Islámica (OCI) en el ámbito de la prevención y la lucha contra el terrorismo internacional. Se concluye que la evolución de las actividades de las organizaciones internacionales puede describirse como un cambio radical en las opiniones de la comunidad internacional del siglo XXI sobre el terrorismo internacional; lo que antes se consideraba un fenómeno que a veces se percibía como importante, pero definitivamente no como un problema estratégico central o grave, ahora, de hecho, tiene el rango de una amenaza existencial para la paz y la seguridad internacionales. Al mismo tiempo, se evidencian problemas sin resolver que comprometen la cooperación internacional por diferencias fundamentales entre los Estados a la hora de definir el terrorismo, arraigadas en sus ideologías, experiencias históricas, intereses, prejuicios y falta de confianzaThe aim of the article is to identify the main directions of activities of organizations (the UN, the European Union, the League of Arab States (LAS) and the Organization of Islamic Cooperation (OIC)) aimed at reducing the radicalization process, influencing the development of extremism and terrorism. In order to achieve the set objective, the main method in the study was document analysis. We have summarized the different concepts and models of radicalization highlighted by researchers in their works. This allowed us to better present the causes of radicalization, and to systematize the normative framework that addresses the activities of organizations (the UN, the European Union, the League of Arab States (LAS) and the Organization of Islamic Cooperation (OIC) in the field of preventing and combating international terrorism. The authors conclude that the evolution of the activities of international organizations can be described as a radical change in the views of the international community in the 21st century on international terrorism. What used to be considered a phenomenon that was at times perceived as important, but definitely not a central or serious strategic problem, now, in fact, has the rank of an existential threat to international peace and security. At the same time, there are many unresolved problems that complicate international co-operation. There are still fundamental differences among States in defining terrorism, rooted in their ideologies, historical experiences, interests, prejudices and lack of trus
Legal Basis for the Creation and Functioning of International Universities in the Republic of Kazakhstan
No full textSin definir el concepto de universidad internacional y resaltar sus características, la legislación kazaja en el campo de la educación superior permite la creación de universidades internacionales basadas en acuerdos intergubernamentales o decretos gubernamentales. Sin embargo, la práctica kazaja tomó un rumbo diferente cuando comenzaron a crearse universidades internacionales sin cumplir las condiciones estipuladas por la ley. El objetivo del artículo era discutir la base jurídica para la creación y funcionamiento de universidades internacionales en Kazajstán. El estudio implicó un análisis en profundidad de la legislación de Kazajstán relativa a la educación superior y las universidades internacionales. Esto incluyó una revisión de documentos legales, un análisis comparativo con estándares internacionales y un examen de estudios de casos de universidades internacionales existentes en Kazajstán. Se analizaron aproximaciones al concepto y contenido de las universidades internacionales en la literatura científica. Según la doctrina científica y la práctica de creación y funcionamiento de universidades, el concepto de universidades internacionales comprende una lista más amplia de universidades basada en diversos criterios que los previstos por la legislación kazaja. Para clasificar algunas universidades como internacionales, se definió el alcance de sus actividades, que debía ir más allá del sistema nacional de educación y ciencia, como lo demuestra el trabajo de una universidad en la internacionalización de la educación, contribuyendo a la interacción intercultural e internacional. El artículo destaca que la legislación kazaja clasifica a las universidades como internacionales sólo si han sido creadas gracias al esfuerzo de representantes de dos o más países. Sin embargo, este enfoque no refleja el funcionamiento real de las universidades internacionales. El documento también propone formas de mejorar la legislación actual para reflejar adecuadamente el establecimiento y el sistema de actividades de las universidades internacionales.Without defining the concept of an international university and highlighting its features, Kazakh legislation in the field of higher education allows the creation of international universities based on intergovernmental agreements or government decrees. However, Kazakh practice took a different path when international universities began to be established without complying with the conditions stipulated by law. The purpose of the article was to discuss the legal basis for the creation and functioning of international universities in Kazakhstan. The study involved an in-depth analysis of Kazakhstan’s legislation pertaining to higher education and international universities. This included a review of legal documents, comparative analysis with international standards, and examination of case studies of existing international universities in Kazakhstan. Approaches to the concept and content of international universities in scientific literature were analyzed. According to the scientific doctrine and practice of creating and operating universities, the concept of international universities comprises a wider list of universities based on various criteria than those provided for by Kazakh legislation. To classify some universities as international, the scope of their activities was defined, which should go beyond the national system of education and science, as evidenced by a university’s work on the internationalization of education, contributing to intercultural and international interaction. The article highlights that Kazakh legislation classifies universities as international only if they are created with the efforts of representatives of two or more countries. However, this approach does not reflect the real functioning of international universities. The paper also proposes ways to improve the current legislation to adequately reflect the establishment and system of activities of international universities