In search of guaranteeing global energy requirements, waste from different agricultural, forestry and industrial sources is presented as a renewable and sustainable energy source. The manufacture of solid fuels from biomass based on the densification of this to improve its mechanical and energy properties is one of the mechanisms of viable energy production from the technical-economic point of view. The biomass mixture is one of the topics currently researched, in which various factors can affect the final behavior of the briquettes. In this research the influence on the mechanical properties of briquettes obtained from the mixture between two biomasses is studied: rice husk and pine sawdust. A mixed factorial experimental factorial design is used, in which the process temperature, the proportion of the rice husk biomass over the total mass, and the compaction time are defined as experimental factors. Experimental statistical models are obtained that partially explain the behavior of several responses that characterize the mechanical properties of the briquettes based on the selected independent parameters. It was found that the mechanical durability of the briquettes is higher than 97.5%, meets the existing standards, like German Institute for Standardization (DIN) 51731, Theological Institute Batista Ebenézer (ITEBE) SS187120 or International Organization for Standardization (ISO) 17225-2, for a compaction temperature of 110 °C and a proportion of rice husk that does not exceed 60% of the total biomass mixture in the briquette. The compaction time was also statistically significant to achieve a briquettes density and an appropriate elasticity modulus in the briquettes. The results of this research are of interest and can serve as a starting point for the design of the industrial process of densification of these two mixed biomasses.
This article reviews technological advances and global trends in the diagnosis, treatment, and monitoring of cardiovascular diseases. A bibliometric analysis was conducted using the SCOPUS database, following PRISMA-ScR guidelines, to identify relevant publications on technologies applied in the diagnosis and treatment of cardiovascular diseases. An increase in scientific output since 2018 was observed, reflecting a growing interest in the technologies available for the treatment of cardiovascular diseases, with terms such as “telemedicine”, “artificial intelligence”, “image analysis”, and “cardiovascular disease” standing out as some of the most commonly used terms in reference to CVDs. Significant trends were identified, such as the use of artificial intelligence in precision medicine and machine learning algorithms to analyse data and predict cardiovascular risk, as well as advances in image analysis and 3D printing. Highlighting the role of artificial intelligence in the diagnosis and continuous monitoring of cardiovascular diseases, showing its potential to improve prognosis and reduce the incidence of acute cardiovascular events, this study presents the integration of traditional cardiology methods with digital health technologies—through a transdisciplinary approach—as a new direction in cardiovascular health, emphasising individualised care and improved clinical outcomes. These advances have great potential to impact healthcare, and as this field expands, it is crucial to understand the current research landscape and direction in order to take advantage of each technological advancement for improving the diagnosis, treatment, and quality of life of cardiovascular patients. It is concluded that the integration of these technologies into clinical practice has important implications for public health. Early detection and personalised treatment of cardiovascular diseases (CVDs) can significantly reduce the morbidity and mortality associated with these diseases. In addition, the optimisation of public health resources through telemedicine and telecare can improve access to quality care. The implementation of these technologies can be a crucial step towards reducing the global burden of cardiovascular diseases.
In this paper a study on the process of densification of oil palm empty fruit bunches (OPEFB) is presented. An empirical-statistical model that allows the evaluation of densification process is obtained through an experimental factorial design. The main purpose of the experimental arrangement is to find the appropriate reference values for the experimental factors - moisture content, fiber length and compaction time-with which optimal performance responses of briquettes are achieved. Statistical models are obtained that explain in an acceptable way the influence of independent experimental factors on the mechanical properties of briquettes, such as briquettes density, durability index and compressive strength. It is possible to conclude that briquettes manufactured with the appropriate reference values, moisture content of 8% w.b., fiber length of 73.6 mm and a compaction time of 26.6 s respectively, meet mechanical and thermal requirements that are required in the most representative standards for biomass briquettes for energy purposes. Results obtained in the current investigation can be used as reference for the design of an industrial pilot plant destined to the densification of EFB of African oil palm.
Este artículo tiene como objetivo determinar la correlación existente entre las variables que potencian la capacidad de aprendizaje asociada al desarrollo de la investigación en las Instituciones de educación superior. Con tal propósito se utiliza la técnica multivariada de análisis de conglomerados de variables y se construye el clúster jerárquico utilizando el software SPSS. A partir del método ward para agrupación de clúster e intervalo de distancia euclídea cuadrado, se identifican los grupos que se forman. Esta selección de conglomerados se corrobora con la técnica multivariada de análisis de componentes principales, con un análisis de matriz de correlaciones de KMO (Kaiser, Meyer y Olkin) y prueba de esfericidad de Bartlett. El análisis mostró que la capacidad de aprendizaje presenta una fuerte interacción con el sector externo, reflejado por el alto nivel de relación entre alianzas y políticas institucionales y de estos con el desarrollo de convenios. La capacitación y formación de posgrado de los investigadores y la vigilancia de los saberes presentan un menor nivel de correlación con las demás variables.
The under-utilization of rice husk, a milling by-product, demands attention due to its widespread disposal and limited usage. This research aims to assess the physical properties and mechanical behavior of three rice husk varieties (F 2000, Orizyca, and Panorama 394), to determine their strength capacities and potential applications. Mechanical properties are evaluated through a non-standardized tension test using a universal machine. Subsequent analyses include measuring the moisture content following ASTM D1348, determining the particle size distribution through ASAE Standard S319, and establishing the bulk density using ASAE Standard S269 Method 4. Mechanical resistance in the rice husk varieties ranged from 60 MPa to 130 MPa, with a particle density exceeding 300 kg/m3 and an average apparent density of 140 kg/m3. Scanning electron microscopy revealed the husk structures, identifying epidermis, hypodermis, and sub-hypodermis layers. The mechanical stress of the Orizyca variety was 1.89 times higher than that of F 2000, and 1.18 times higher than that of Panorama 394. Potential applications include brick manufacturing and thermoformed materials for Orizyca and Panorama 394, while F 2000 could be utilized for producing fuel briquettes or cardboard, among other possibilities.
This research deals with the fatigue behavior of butt-welded joints, by considering the geometry and post-welding cooling cycles, as a result of cooling in quiet air and immersed in water. ASTM A-36 HR structural steel was used as the base metal for the shielded metal arc welding (SMAW) process with welding electrode E6013. The welding reinforcement was 1 mm and 3 mm, respectively; axial fatigue tests were carried out to determine the life and behavior in cracks propagation of the tested welded joints, mechanical characterization tests of properties in welded joints such as microhardness, Charpy impact test and metallographic analysis were carried out. The latter were used as input for the analysis by finite elements which influence the initiation and propagation of cracks and the evaluation of stress intensity factors (SIF). The latter led to obtaining the crack propagation rate and the geometric factor. The tested specimens were analyzed, by taking photographs of the cracks at its beginning in order to make a count of the marks at the origin of the crack. From the results obtained and the marks count, the fatigue crack growth rate and the influence of the cooling media on the life of the welded joint are validated, according to the experimental results. It can be concluded that the welded joints with a higher weld reinforcement have a shorter fatigue life. This is due to the stress concentration that occurs in the vicinity of the weld toe.