University of Cádiz
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Prediction and Detection of Localised Corrosion Attack of Stainless Steel in Biogas Production: A Machine Learning Classification Approach
Get PDFBiogas contributes to environmental protection by reducing greenhouse gas emissions and promoting the recycling of organic waste. Its utilization plays a crucial role in addressing the challenges of climate change and sustainability. However, the deterioration of process plants involved in biogas production due to corrosion has a critical impact on the safety and durability of their operations. In order to maintain the safety of structures in terms of service life with respect to corrosion, it is essential to develop effective corrosion engineering control methods. Electrochemical techniques have become a useful tool by which to evaluate corrosion resistance. However, these techniques may require microscopic analysis of the material surface and the analysis may be influenced by subjective factors. To solve this drawback, this work proposes the use of SVM models to predict the corrosion status of the material used in biogas production with no need to perform microscopic analysis after the electrochemical test. The obtained results of sensitivity and specificity equal to 0.94 and 0.97, respectively, revealed the utility of the proposed stochastic models to assure the corrosion state of the equipment involved in biogas production. SVM-based models are an effective alternative for accurately evaluating material durability and comparing the corrosion resistance of different materials in biogas environments. This approach facilitates the selection of the most suitable material to achieve greater durability and long-term performance. Synopsis: The results show that the proposed model is a useful tool to predict the behaviour of stainless steel against corrosion according to the environmental conditions to which the material is exposed in biogas production
The k-Distance Mutual-Visibility Problem in Graphs
Get PDFThe concept of mutual visibility in graphs, introduced recently, addresses a fundamental problem in Graph Theory concerning the identification of the largest set of vertices in a graph such that any two vertices have a shortest path connecting them, excluding internal vertices of the set. Originally motivated by some challenges in Computer Science related to robot navigation, the problem seeks to ensure unobstructed communication channels between navigating entities. The mutual-visibility problem involves determining a largest mutual-visibility set in a graph. The mutual-visibility number of a graph represents the cardinality of the largest mutual-visibility set. This concept has sparked significant research interest, leading to connections with classical combinatorial problems like the Zarankiewicz problem and Turán-type problems. In this paper, we consider practical limitations in network visibility and our investigation extends the original concept to k-distance mutual-visibility. In this case, a pair of vertices is considered S-visible if a shortest path of length at most k exists, excluding internal vertices belonging to the set S. The k-distance mutual-visibility number represents the cardinality of a largest k-distance mutual-visibility set. We initiate the study of this new graph parameter. We prove that the associate decision problem belongs to the NP-complete class. We also give some properties and tight bounds, as well as, the exact value of such parameter for some particular non trivial graph classes
From Sand to Bell: Novel Predation of Scyphozoans by the Giant Caribbean Sea Anemone Condylactis gigantea (Weinland, 1860) from the Western Atlantic
Get PDFPredation is a fundamental ecological process that shapes marine ecosystem dynamics. This study reveals a novel predator–prey interaction between the giant Caribbean sea anemone Condylactis gigantea and the two jellyfish species Cassiopea sp. and Aurelia sp., challenging traditional understanding of sea anemone feeding habits. Observations from citizen science platforms and field recordings documented C. gigantea successfully capturing and consuming these gelatinous marine organisms. The research highlights the trophic plasticity of C. gigantea, demonstrating its ability to prey on larger gelatinous organisms beyond its traditionally known diet. This predation event represents a possible benthic–pelagic coupling mechanism and underscores the value of citizen science in capturing rare ecological interactions
Sistemas de Gobierno del Buque, Capítulo 9. El Timón
No full textEstas transparencias corresponden al video del mismo nombre, publicado en Youtube, dentro de la página del Grupo Señales, Sistemas y Comunicaciones Navales de la UCAEstas transparencias corresponden al video del mismo nombre, publicado en Youtube, dentro de la página del Grupo Señales, Sistemas y Comunicaciones Navales de la UC
Sistemas de Gobierno del Buque. Capítulo 11. La Maniobrabilidad del Buque
No full textEn esta obra se reproducen las transparencias del video del mismo nombre, depositado en Youtube y realizado por el Grupo Señales, Sistemas y Comunicaciones Navales de la UCA.En esta obra se reproducen las transparencias del video del mismo nombre, depositado en Youtube y realizado por el Grupo Señales, Sistemas y Comunicaciones Navales de la UCA
Green Gaming: Automated Energy Consumption Reduction for Doom Engine
No full textThe video games industry dominates the entertainment market, standing among one of the most significant sectors in the world. Its continuous and rapid growth, driven by both the expanding player base and the increasing complexity of modern games, has significantly increased global energy consumption, estimated between 230 TWh and 347 TWh annually. The application of generic optimizations when compiling games leads to inefficient performance and unnecessary energy use. Consequently, this work presents a novel method for reducing video games energy consumption by tailoring software optimizations for the specific underlying hardware architecture. This is defined as a combinatorial optimization problem, formulated as finding the optimal sequence of LLVM code transformations that modify the considered game into an optimized version with minimum energy use. A cellular genetic algorithm is employed to optimize Doom Legacy —a modern adaptation of the original Doom engine— running on a Raspberry Pi 4. Greener versions of the software were found, compared to the performance of the popular -O3 compilation flag (the most aggressive generic LLVM optimization), achieving 26 times lower consumption values. This significant improvement results in dozens of joules saved for one hour gameplay, enhancing energy efficiency in consumer electronics as mobile devices and gaming platforms, positively impacting battery life and greenness performance
Efectividad de una intervención multicomponente para promover la actividad física durante la jornada escolar: justificación y métodos del estudio MOVESCHOOL
No full textBackground: Increasing levels of physical activity (PA) and reducing sedentary time among adolescents during the school day is a pressing need. Emerging methodologies and strategies been shown to be effective in increasing PA levels and providing additional benefits for students, such us physically active lessons (PAL), active breaks (AB) and active recesses (AR). However, evidence concerning adolescents remains limited. This manuscript presents the methods and rationale of the MOVESCHOOL study, which aims was to examine the effects of a multicomponent school-based intervention during the school day on indicators of PA, sedentary time, health, executive functions and education in adolescents.
Methods: A quasi-experimental study was conducted with the aim to involve a total of 800 students aged 12–14 years old from 11 schools (7th and 8th grade) in south-western Spain, five schools forming the intervention group and six schools forming the control group. The evaluation included two independent measurements: pre-intervention and post-intervention. The interventio n lasted 29 weeks and consisted of a multi-component programme including a weekly PAL, two 5 min daily AB, and a daily AR. Primary outcomes included accelerometer based PA and sedentary time, health-related physical fitness, academic indicators, and executive functions. For statistical analyses, descriptive, correlational, regression, and repeated measures ANOVA analyses will be applied. Additionally, qualitative data were gathered through semi-structured individual interviews and focus groups, and information will be evaluated with thematic analysis.
Discussion: The MOVESCHOOL study represents a pioneering effort in Spain, being the first of its kind to evaluate the effectiveness of a multicomponent programme in secondary schools. Furthermore, this project provides valuable insights into the effects of a multicomponent school-based PA intervention on PA levels, sedentary time, health-related, cognitive, academic indicators and psychological health markers in secondary school students. The results of this study will make a significant contribution to the educational community, providing them with innovative teaching methods and strategies that have the potential to increase PA levels during the school day. In addition, this research promises to provide a transformative experience for educators, equipping them with tools to promote the holistic development of their students, enriching their academic performance and enhancing their well-being.
Clinical trial registration: ClinicalTrials.gov, identifier NCT06254638
Biotransformation of Thiochroman Derivatives Using Marine-Derived Fungi: Isolation, Characterization, and Antimicrobial Activity
Get PDFThiochroman derivatives are highly versatile molecules widely used for the synthesis of novel heterocycles and bioactive compounds. In our study, we conducted the biotransformation of thiochroman-4-ol (1) and 6-chlorothiochroman-4-ol (1a) using the marine-derived fungal strains Emericellopsis maritima BC17 and Purpureocillium lilacinum BC17-2. Biotransformations yielded ten known thiochroman derivatives along with the compound 1-(5-chloro-2-(methylthio)phenyl)propane-1,3-diol (6a), which was described for the first time. Moreover, we successfully characterized the stereoisomers of sulfoxides 3 and 3a. Their structures and absolute configurations were established though comprehensive analyses of NMR, HR ESI-MS, and ECD spectra, as well as by using Mosher’s method. Antimicrobial activity of the isolated metabolites was evaluated against bacterial and fungal human pathogens, specifically Staphylococcus aureus ATCC 29213, Escherichia coli ATCC25922, and Candida albicans HPM-1922816
First Records of Wild Octopus (Octopus vulgaris) Preying on Adult Invasive Blue Crabs (Callinectes sapidus)
Get PDFThe Atlantic blue crab, Callinectes sapidus, has rapidly expanded its invasive range ubiquitously in the Mediterranean Sea, posing ecological threats to native ecosystems. In its native habitat, the crab plays a crucial role in the ecosystem, but in invaded areas, it lacks natural predators. This has led to rapid expansion, highlighting the need to monitor and understand biological interactions with the native community. This study reports, for the first time in the wild, the predation of the invasive blue crab by the common octopus, Octopus vulgaris, in the Mediterranean Sea. Three sequences (two videos and a photography series) recorded by two spearfisherman (observation 1 and 2) and a recreational SCUBA diver (observation 3) are described. This article highlights the importance of native predators in influencing the expansion or control of invasive species. Additionally, it showcases the capacity of a versatile predator (the octopus), to serve as an ally alongside the fishing strategy, suggesting a novel perspective for ecologically sustainable management, in a context of low native predators of the blue crab. The collaboration with citizen scientists proves crucial in expanding our understanding of predator–prey dynamics and ecological interactions, underlining the need for continued partnerships between researchers and society for effective invasive species management
The Role of Surface {010} Facets in Improving the NOx Depolluting Activity of TiO2 and Its Application on Building Materials
Get PDFAir pollution, a major health concern, necessitates innovative solutions such as TiO2-based photocatalytic building materials to combat its harmful effects. This study focuses on developing high-performance TiO2 photocatalysts for NOx removal in building applications, aiming to overcome the limitations of commercial TiO2. These photocatalysts were synthesized via a hydrothermal method, with parameters such as synthesis time and post-treatment investigated to optimize their properties. Hydrothermal synthesis yielded TiO2 nanoparticles with reduced aggregation and a high proportion of elongated particles with exposed {010} facets. This resulted in significantly enhanced photocatalytic activity compared to commercial P25 in methylene blue degradation and NOx depollution. Subsequently, the optimized hydrothermal TiO2 was successfully integrated into a silica sol–gel coating for application on building materials. The coated concrete demonstrated significantly higher NOx removal efficiency and lower NO2 release, achieving a 1.7-fold improvement in overall NOx removal and significantly higher depolluting effectiveness compared to its P25 counterpart. These findings highlight the potential of hydrothermally synthesized TiO2 with controlled morphology for the development of high-performance, environmentally friendly building materials with enhanced air purification capabilities