The growing global demand for sustainable energy has intensified interest in biomass residues as viable feedstocks for biofuels and bio-based production. This review systematically examines advances in the utilization of biomass residues, spanning upstream assessment through downstream conversion pathways. Using the PRISMA framework, 543 peer-reviewed articles published between 1990 and 2025 were analyzed from the Scopus and Web of Science databases. The review reveals a clear methodological evolution from early residue characterization and physicochemical analyses toward integrated techno-economic, environmental, and system-level assessments. Upstream research increasingly addresses feedstock identification, spatial dispersion, logistics optimization, and pretreatment efficiency, while downstream advances focus on biochemical, thermochemical, and hybrid conversion technologies. Although artificial intelligence and machine learning constitute approximately 2.5–3% of the total historical literature, they account for nearly 18–22% of recent studies in process modeling and yield prediction, achieving predictive accuracies frequently exceeding R² > 0.95. Despite these advances, persistent challenges remain in biomass logistics, feedstock heterogeneity, and technology scaling. Emerging trends highlight hybrid frameworks that integrate data-driven and mechanistic models to enhance efficiency, circularity, and commercial feasibility in bioenergy systems.

The phenomena of capillarity, dipole–dipole attractions, and hydrogen bonding make the application of mass transfer models to predict the drying rate by air convection in wood chips imprecise. So, the modification of these models by tailoring their equations is required. This study aims to adapt theoretical mass transfer models to improve the prediction of drying time for Pinus spp. chips subjected to a known hot air stream with known velocity, temperature, and relative humidity. An experimental device was constructed to control the variables, where the air stream passes vertically through a cylinder filled with wood chips. The tested air velocities ranged between 7 and 10 m/s, with relative humidity between 10 and 30% and temperatures between 40 and 70 °C with 3 and 6 cm chip columns. It was demonstrated that the drying rate of chips in a convective process with air is not constant but rather decreases over time, and that the critical moisture content is above 42%. Factors such as the height of the chips pile influence the predictive equations for the drying rate. The average relative drying rate ranged between 0.063 and 0.040 g of water s⁻¹ kg of dry chip⁻¹ in both heights; meanwhile, the average absolute drying rate was between 0.0031 and 0.0032 g of water s⁻¹. Modifications of the models have been developed that adjust theoretical values with experimental values, resulting in an r² value of 0.80.

El desempeño logístico es un motor fundamental para el crecimiento económico y la integración territorial en Ecuador. Las diferencias regionales en capacidades y recursos afectan la competitividad y el acceso a mercados. El presente estudio tiene como objetivo analizar la competitividad logística de las regiones del Ecuador (Costa, Sierra, Insular y Oriente) a partir de la evaluación de la infraestructura existente, los servicios logísticos disponibles y las condiciones de movilidad. Se empleó un enfoque cuantitativo-descriptivo, utilizando como instrumentos la Encuesta Nacional de Logística y el Índice de Competitividad Logística Regional (ICLR). Los resultados revelan disparidades, la Región Insular se posiciona como la más competitiva, gracias a su infraestructura portuaria y aeroportuaria sólida, así como a su oferta robusta de servicios logísticos especializados. En contraste, la Región Oriental presenta serias deficiencias estructurales que afectan su conectividad y eficiencia operativa. La Sierra y la Costa muestran fortalezas parciales, pero enfrentan limitaciones críticas en movilidad urbana, seguridad y logística nocturna.

This research aimed to analyze and adjust the theoretical equations used in mass transfer models to estimate the drying rate in pine wood chips, considering different chip column heights and particle sizes. For this purpose, an experimental biomass dryer was designed and built, which allowed, under different levels of minimum and maximum capacity, to establish a series of drying treatments evaluated under different conditions. One of the main contributions of this work lies in the novel equations that allow, from air parameters, to accurately calculate the drying rate and, therefore, to estimate the time required for complete drying of forest biomass. This is achieved through regression models applied in an innovative way, offering new predictive tools and establishing a clear and replicable procedure for its application in practice. The results obtained in this study demonstrate that wood chip drying is not a linear process; the drying rate decreases over time and is affected by factors such as particle size and operating conditions such as air speed and temperature. The drying process exhibited a relative drying rate ranging from 0.0380 g/s·kg in small particles (at low air velocities and temperatures) to 0.0695 g/s·kg in large particles (at high air velocities and temperatures). The absolute drying rate varied between 0.0034 g/s in small particles and 0.0057 g/s in large particles. The findings revealed that the models explained between 58% and 83% of the variability observed in the treatments. Statement of Novelty. This research arises from the need to more accurately predict the drying time of pine wood chips, a fundamental aspect for optimizing biofuel production. Currently, experimental drying models using hot airflows have limitations, as they are designed for fixed environmental conditions of temperature, flow rate, and relative humidity, making their application challenging in environments with variations in these variables. To overcome these limitations, some studies have proposed models based on the analysis of mass and heat transfer phenomena to predict the drying rate. However, the number of influencing factors still causes theoretical data to not precisely match experimental data. This study proposes complementing mass transfer equation-based models adapted to kinetic models with experimental data fitting models, significantly improving prediction accuracy. Since drying processes depend on the Biot number in mass transfer and the Biot number in heat transfer, which assess the relationship between diffusion and convection in each subsystem based on the size of the solids undergoing drying, this work introduces differentiated equations for different size ranges of wood chips. The main contribution lies in integrating theoretical data into equations that more accurately reflect experimental results, providing an innovative tool for both the scientific and industrial communities. This approach not only allows for adjusting production times based on real environmental conditions but also contributes to improving energy efficiency and sustainability in the bioenergy industry, ensuring that biomass reaches the appropriate moisture level for use as biofuel.

This work focuses on testing and validating a prototype device for measuring mass transfer phenomena in biomass drying processes, patented by the Universitat Politècnica de València (UPV) and Escuela Politécnica del Litoral (ESPOL), WO2025/109237 A1. The first step involved evaluating and calibrating the sensors of the measuring device to ensure accurate and consistent measurements. Subsequently, extensive tests were conducted to validate the prototype’s functionality for obtaining mass diffusivity and the mass transfer coefficient by convection at the solid-air interface. Finally, the results obtained were compared with those provided by existing predictive theoretical models in the literature. Areas for improvement in the theoretical models were identified, and adjustments were made to optimize prediction. The study highlights that the theoretical Sherwood method for estimating the mass transfer coefficient shows discrepancies with experimental data, mainly due to the assumption that the transfer coefficient remains constant during drying, whereas it actually varies with the material’s moisture content. This leads to inaccuracies that affect the efficiency of industrial drying systems. The prototype proved effective in measuring both diffusivity and mass transfer coefficient, validating the method.

El gel de Aloe vera (Aloe barbadensis Miller) es una fuente natural de compuestos bioactivos con potencial aplicación en alimentos funcionales; sin embargo, su extracción eficiente y su incorporación en productos alimenticios presentan desafíos, especialmente en términos de aceptabilidad sensorial. El objetivo de este estudio fue optimizar el método manual de extracción del gel y evaluar su aplicación en productos derivados, como mermeladas y cubos deshidratados, para enriquecer la bebida de yogur griego. La investigación adoptó un enfoque metodológico mixto, combinando análisis cuantitativos y cualitativos, y empleó un diseño experimental. Se compararon tres técnicas de extracción manual (escurrimiento simple, frotación manual y fileteado), encontrando que el fileteado obtuvo el mayor rendimiento (0.62 ± 0.03 g/g; p < 0.05). El gel extraído fue caracterizado fisicoquímicamente (pH 4.53, acidez 0.43 %, 0.99 °Brix, humedad 97.87 %) y se utilizó en cinco formulaciones de mermelada con piña, además de cubos obtenidos mediante deshidratación osmótica. La evaluación sensorial, realizada con 50 panelistas no entrenados, mostró una preferencia significativa por la formulación 50 % Aloe vera / 50 % piña, tanto de forma independiente como al ser incorporada en yogur griego (p < 0.0001 en todos los atributos evaluados). Esta mermelada presentó parámetros fisicoquímicos adecuados (pH 2.91, acidez 0.26 %, 65.67 °Brix), compatibles con los estándares comerciales. Los resultados evidencian un proceso integral que va desde la extracción del gel hasta su aplicación exitosa en alimentos fermentados, proponiendo una alternativa viable y sensorialmente aceptable para la incorporación funcional del Aloe vera en productos lácteos.