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Experimental evaluation of natural CO2-based mixtures with hydrocarbons R290 and R1270 in a transcritical refrigeration plant
No full textIn light of the low performance of the basic CO2 transcritical refrigeration cycle, this study explores several CO2-hydrocarbon blends to enhance the Coefficient of Performance (COP) and, consequently, minimise the cycle's electrical power consumption. Based on a single-stage cycle with IHX four blends of carbon dioxide/propylene (CO2/R1270) and carbon dioxide/propane (CO2/R290) (96/4 %mass and 94/6 %mass each) were tested at identical operating conditions rejecting heat to three temperature levels (20, 27, and 34 °C) with similar cooling demanding conditions (0 °C). Test results revealed COP improvements at transcritical conditions up to 9.7 % using a 4 %mass of R1270 and up to 4.7 % with a 6 %mass of R290. Furthermore, by adding 4 %mass of R1270, the resulting mixture increases the cooling capacity from 2.3 to 5.8 % regardless of the heat rejection temperature. Finally, the compressor power consumption showed a significant reduction from 1.2 to 7.4 % compared to pure CO2, mainly due to improved compressor efficiencies by mixtures. The results demonstrate the convenience of using CO2 – hydrocarbon mixtures as drop-ins to replace pure CO2 in existing transcritical plants.Funding for open access charge: CRUE-Universitat Jaume
Eficacia y seguridad de la colonoscopia asistida por ENDOCUFF VISION® vs. Colonoscopia estándar en el programa de cribado de cáncer colorrectal: ensayo clínico aleatorizado, prospectivo, multicéntrico, abierto y de grupos paralelos.
No full textSe evaluó la efectividad y seguridad de la colonoscopia asistida por Endocuff Vision comparada con la colonoscopia estándar en los pacientes del programa nacional de cribado de cáncer colorrectal. Se realizó un ensayo clínico aleatorizado, prospectivo, multicéntrico, abierto y de grupos paralelos entre noviembre 2020-octubre 2021 en 5 centros en España. Se incluyeron pacientes que presentaban un test de sangre oculta positivo previo. Se aleatorizaron en dos grupos según se realizara la colonoscopia estándar (SC) o utilizando Endocuff Vision (EVAC). El objetivo principal era evaluar la tasa de detección de adenomas (TDA). Se incluyeron un total de 822 pacientes (410 EVAC y 412 SC). La TDA fue significativamente mayor en el grupo EVAC (59,8% vs 51%; p=0,02). Hubo 11 colonoscopias incompletas en cada grupo (2,7% frente a 2,7%; p=0,99). No se observaron diferencias en los efectos adversos (0,24% frente a 0,24%).Colorectal cancer (CRC) screening aims to detect precancerous lesions to reduce interval cancer incidence. Colonoscopy is the standard diagnostic technique, but some lesions may be missed. Endocuff Vision® is a device designed to improve colonic mucosa visibility. This study evaluated its effectiveness and safety compared to standard colonoscopy within the Spanish national CRC screening program. A randomized, multicenter, prospective clinical trial was conducted with 822 patients aged 50–70 years with a positive fecal occult blood test. Patients were assigned to undergo either Endocuff Vision-assisted colonoscopy (EVAC) or standard colonoscopy (SC). The adenoma detection rate was significantly higher in the EVAC group (59.8% vs. 51%; p=0.02). There were no differences in incomplete colonoscopies or adverse events between groups. In conclusion, Endocuff Vision improves adenoma detection without increasing risks, contributing to a reduction in interval CRC cases.Programa de Doctorat en Ciències Biomèdiques i Salu
Multimodal Engagement in EFL: Teaching Reported Speech with YouTube Shorts and Digital Tools
No full textMàster Universitari en Professor/a d'Educació Secundària Obligatòria i Batxillerat, Formació Professional i Ensenyaments d'Idiomes. Codi: SAP419. Curs acadèmic: 2024/2025This research explores the integration of multimodal resources into the teaching of reported speech in a B2-level English as a Foreign Language (EFL) classroom at an Official School of Languages (EOI) in the Valencian Community. The study responds to the limitations of traditional textbook materials, which often present grammar in isolated and decontextualised formats. The proposal combined an authentic YouTube Short and three interactive digital tools, Baamboozle, Kahoot, and Quizlet, with the aim of fostering learner engagement, enhancing grammar comprehension and supporting digital competence. The YouTube Short was analysed using the GRAPE-MARS multimodal annotation software to identify co-occurring modes such as spoken language, intonation, facial expression and visual layering. Ethnographic data were collected through two student questionnaires, before and after the intervention. The results show that students found multimodal materials more engaging and helpful than traditional resources, particularly due to their visual, interactive and authentic nature. The findings support the inclusion of multimodal resources in EFL instruction, offering a pedagogical alternative that aligns with Common European Framework of Reference for Languages (CEFR) objectives and current digital communication practices
Physical activity induced functional and structural changes in the Hippocampus and the Reward System
No full textCompendi d'articles, Doctorat internacionalThis thesis explores the effects of physical activity (PA) on the brain of young adults through four empirical studies that examine both structural and functional changes associated with regular and acute exercise. By combining accelerometry, self-reports, cognitive testing, and neuroimaging techniques, the relationship between PA, mood, cognition, and individual variables such as personality and physical fitness is investigated. The results show that regions such as the hippocampus and the anterior cingulate cortex (ACC) are particularly sensitive to activity and sedentary levels, and that this relationship is modulated by individual differences. Furthermore, immediate effects of acute exercise on medial temporal lobe connectivity are observed, along with a reduction in hippocampal volume after only 14 days of inactivity. Taken together, these findings highlight the high brain plasticity in young adults and the relevance of regular PA for neurocognitive health.Programa de Doctorat en Psicologi
Datafeudalism and Democracy: The Domination of Big Tech Corporations in the Age of Generative AI
No full textCompendi d'articles, Doctorat internacionalThis doctoral thesis examines the adverse effects stemming from the transformation of digital giants’ socio-economic model —from surveillance capitalism to datafeudalism— and from the rapid emergence and popularisation of generative AI (GenAI) tools on European Union (EU) democratic systems. The research pursues three interrelated objectives. Firstly, it applies a hermeneutic-critical methodological framework to analyse the global system of social, economic, and political domination established by big tech corporations and its detrimental consequences for the proper functioning of EU democracies. Secondly, it examines the dangers posed by the emergence and strategic use of GenAI to the existence of an autonomous and authentic public sphere and to the formation of a critical and mature public opinion. Thirdly, it proposes a set of guidelines aimed at mitigating these threats and enhancing the performance of EU democratic systems in a fair, transparent, responsible, and explainable manner.Programa de Doctorat en Ètica i Democràci
Performance assessment of a hybrid vapor compression-thermoelectric refrigeration system using machine learning models
No full textIn this study, a hybrid refrigeration configuration was developed by integrating thermoelectric cooling (TEC) modules with a conventional vapor compression refrigeration (VCR) system to achieve lower temperatures in a freezer compartment. Experimental tests were conducted under various conditions, with the TEC voltage varied between 5.5 and 7.5 V, as determined by initial trials, to achieve optimal performance. Three airflow rates (0, 0.4, and 1.2 m/s) were used within the freezer to represent natural and forced convection modes. A regulated DC voltage source supplied TEC modules. The hot side heat of the TEC was transferred to the refrigerant via an aluminum heat exchanger, with a cold side heat sink and fans being employed. To predict system performance, five artificial intelligence models were developed, including Artificial Neural Network (ANN), Random Forest (RF), Extreme Gradient Boosting (XGB), AdaBoost (AB), and k-Nearest Neighbor (KNN). Among them, the Artificial Neural Network model was the most accurate, with R2 values exceeding 0.98 and the lowest mean absolute error (MAE) in forecasting all variables. Experimentally, the interior chamber temperature decreased from approximately −26 °C under static air conditions to −30.5 °C with a 7.5 V TEC voltage and 1.2 m/s airflow. Furthermore, the cold side temperature increased from −37.5 °C at 0 m/s to −34 °C at 1.2 m/s for the lowest voltage of 5.5 V, indicating a 3.5 °C decrease. The maximum COP of 0.96 was achieved at 5.5 V and decreased with increasing voltage, indicating a trade-off between increased cooling power and efficiency. This hybrid strategy presents a promising route for sustainable and effective use in sustainable refrigeration systems, especially for achieving ultra-low temperatures while maintaining controlled heat rejection
PRÁCTICAS MI 1822 Fundamentos y Didáctica de la Expresión Musical
No full textEl recurso educativo que se presenta corresponde al temario de problemas de la asignatura MI 1822 Fundamentos y Didáctica de la Expresión Musical del Grado en Maestra/a de Educación Infantil. Constituye un material docente de acceso abierto que integra actividades de enseñanza práctica como la expresión vocal, el canto, el ritmo, la prosodia o el ejercicio de la lecto-escritura musical
The Castelló trolleybus, heritage of La Plana
No full textThe Castelló trolleybus, heritage of La Plana892In the Spanish post-war period, the lack of liquid fuels led Franco’s authorities to promote means of transport powered by alternative energies such as electricity, favoring the establishment of trolleybus lines. One of them was promoted by the Castelló Provincial Council in 1941 to structure the La Plana region. Delays in its implementation meant that it was not inaugurated until 1961, in a context substantially different from that of two decades ago, characterized by the intensification of the motorization process and the widespread use of private means. This fact ended up causing the network to be dismantled a few years later. However, despite its ephemeral existence, the trolleybus has left an interesting heritage legacy in La Plana that needs to be preserved
Factores de éxito en los equipos de trabajo de los sistemas Lean Management
No full textLos sistemas Lean se basan en una serie de principios cuya implantación incluye recursos técnicos y humanos, donde se desarrollan los equipos de trabajo multifuncionales. El objetivo principal de esta tesis es investigar las dimensiones de los equipos lean que influyen en el funcionamiento de los sistemas Lean y en los Resultados de Operaciones de las empresas. La población del estudio está formada por empresas de diferentes sectores industriales. Los datos se analizan mediante regresión lineal. Los resultados muestran que las características clave de los equipos de trabajo lean son Interdependencia, Formación al equipo, Roles de comportamiento, Toma de decisiones compartida, Liderazgo y Aprendizaje interno y externo del equipo, cuya influencia varía según el tipo de resultado considerado. Estos resultados aportan información para la dirección de los sistemas Lean en general y de los equipos de trabajo en particular.Lean systems are based on a series of principles whose implementation includes technical and human resources, where multifunctional work teams are developed. The main objective of this thesis is to investigate the dimensions of Lean work teams that influence lean and operations performance. The study population are companies from different industrial sectors. Data are analyzed using linear regression analysis. Results show that the key characteristics of work teams are interdependence, team building, behavioral roles, shared decision making, leadership, internal learning team and external learning team. The influence of those variables depends on the type of outcome considered, lean performance, quality, delivery and flexibility. No significant effect is shown when cost performance is considered. These results provide information for the management of Lean systems in general and of work teams in particular.Programa de Doctorat en Economia i Empres