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Study of crystallization and melting-solidification processes in some fatty acids as phase change materials (PCMs)
No full textComunicación presentada en: 13CNIT : 13th National and 4th International Conference in Engineering Thermodynamics : Advances in Engineering Thermodynamics : The Key to Sustainable Development = 13er Congreso Nacional y 4º Congreso Internacional de Ingeniería Termodinámica : Avances en Ingeniería Termodinámica : la clave de un desarrollo sostenible. Jaume I University, Castellón de la Plana (Spain), November 29th, 30th and December 1st, 202
Aprendizaje activo y significativo sobre circuitos eléctricos mediante simulaciones computacionales PHET en estudiantes de nivel medio superior
No full textEn esta tesis investigamos cómo diseñar, implementar y evaluar una estrategia didáctica para enseñar la ley de Ohm y circuitos eléctricos en serie y paralelo de corriente continua, para estudiantes de educación media superior, utilizando las metodologías de Aprendizaje Activo y de Aprendizaje Significativo, esto es, las Clases Demostrativas Interactivas y las Unidades de Enseñanza Potencialmente Significativas. Tanto el Aprendizaje Activo como el Aprendizaje Significativo se encuentran entre los mejores modelos educativos para la enseñanza de la Física en todos los niveles educativos. Hemos realizado una fusión de ambas propuestas y los resultados obtenidos son muy alentadores. Nuestra propuesta educativa se estructuró mediante Clases Demostrativas Interactivas utilizando simulaciones computacionales PhET. También, calculamos el factor de ganancia del aprendizaje de Hake, el factor de concentración de Bao-Redish, además de utilizar análisis de Rasch, también realizamos un breve análisis de t de student y un cuestionario de diferencial semántico.In this thesis we investigate how to design, implement and evaluate a didactic strategy to teach Ohm's law and electrical circuits in series and parallel direct current, for high school students, using the Active Learning and Meaningful Learning methodologies, that is, the Interactive Demonstrative Classes and the Potentially Meaningful Teaching Units. Both Active Learning and Meaningful Learning are among the best educational models for teaching Physics at all educational levels. We have made a merger of both proposals and the results obtained are very encouraging. Our educational proposal was structured through Interactive Demonstrative Classes using PhET computer simulations. In addition, we calculated the Hake learning gain factor, the Bao-Redish concentration factor, in addition to using Rasch analysis, we also performed a brief student's t-analysis and a semantic differential questionnaire
Nuevos Complejos Metálicos de Pt(II), Ir(III), Ru(II) y Rh(III) con Propiedades Anticancerígenas y Antimicrobianas
No full textEl cáncer y las enfermedades infecciosas provocadas por bacterias resistentes a los antibióticos son dos de las principales causas de muerte en los países desarrollados. Los graves efectos secundarios que producen los tratamientos anticancerígenos, así como el incremento de la resistencia a los antibióticos actuales y la ausencia de nuevos antimicrobianos en el mercado, ha puesto de manifiesto la necesidad de buscar nuevas alternativas terapéuticas que produzcan menos efectos secundarios y que sean capaces de vencer las resistencias bacterianas. En este contexto, los complejos metálicos han sido considerados como unos posibles candidatos para el tratamiento del cáncer y de las enfermedades infecciosas. En la presente tesis doctoral se han estudiado las características fisicoquímicas y las propiedades anticancerígenas y antimicrobianas de nuevos complejos metálicos de Pt(II), Ir(III), Ru(II) y Rh(III) en condiciones de oscuridad y bajo irradiación. Para ello, se emplearon líneas celulares cancerígenas humanas y cepas bacterianas de interés clínico. Además, se evaluó la influencia de la estructura de los complejos en su actividad.Cancer and the emergence of multi-drug resistant microorganisms are two of the main causes of death in developed countries. In addition, the global rise of antibiotic resistance and the lack of new antimicrobials on the market are major challenges facing modern medicine nowadays. Therefore, there is a real need to synthesize some more effective antitumour drugs with minimal side effects and new antimicrobial agents able to overcome bacteria resistance. Currently, metal complexes have been considered as a new and promising alternative to treat cancer and infectious diseases, since their threedimensional shape and the coordinated ligands can modulate their pharmacological properties. In this thesis, new Pt(II), Ir(III) and Ru(II) complexes were synthesized by Dra Monica Vaquero and the organometallic Ir(III) and Rh(III) complexes were synthesized by Dr Igor Echevarria, both from the University of Burgos. These complexes were physicochemically characterized, and their antitumour and antibacterial activities were determined both in the dark and upon photoactivation. For this purpose, several human tumour cells and clinically relevant bacterial strains were employed. Moreover, structure–activity relationships were unveiled, showing other chemical optimizations of novel Pt(II), Ir(III), Ru(II) and Rh(III) derivatives
Accounting in the Anthropocene: Transformations for Sustainability in Research and Organizations
No full textThe following abstract presents a summary of the three research studies that make up this dissertation. The objective, methodology and main findings of the same are presented below, structured in three chapters. Chapter one studies the production of knowledge by a collaborative initiative of scholars aiming at developing the foundations for a socio-ecologically-centred accounting research program. The Scientific/Intellectual Movements General Theory is the framework for analysis, and the empirical material was gathered through publications and participant observation of more than 60 hours of collective work. The analysis resulted in two main findings: 1) Social and Environmental Accounting Research (SEAR) is the result of a successful Scientific Intellectual Movement (SIM): SEAR is nowadays recognized as a field of research and, following the insights provided by this analysis SEAR developed as the result of a SIM. As the field became normalized, the SIM extinguished. The analysis of the case, the literature produced in SEAR and the nature of the discussions produced by the S-E group revealed that many of the more radical ideas did not survive the institutionalized version of the f ield. However, they continued to be brought up marginally by a part of the research community. 2) Processes of normalization imply the abandonment of a part of the propositions of a SIM, leading to cyclical processes of intellectual grievance that can re-mobilise action. S-E group participants reclaim some of the ideas about the role of ecology and critical approaches in accounting that were present in the emergence of SEAR but became marginalized as the field gained recognition. The field study shows that, while a SIM might extinguish once it is generally accepted and normalized, some of the ideas discarded in this process and still relevant can generate sufficient intellectual dissatisfaction to mobilize a second wave of collective action. In addition to the description of this new dynamic of grievance and mobilization, this study provided a comprehensive analysis of the emergence and evolution of the field from a lens focused on deliberate processes of scientific evolution. Chapter two analyses the multiple meanings of stewardship in accounting research building bridges with sustainability science through two strategies: the analysis of the literature on stewardship in accounting and sustainability/environmental science; and the analysis of the SeaBOS case study. The notion of boundary objects is used to explain the processes by which cooperation is achieved in the absence of consensus. The analysis of SeaBOS revealed that members share a general commitment to stewardship, but the more concrete application of the object by different members shows substantial differences. They give rise to the following three propositions: 1) A new vision of materiality: current frameworks/standards of corporate sustainability reporting define the content of corporate reports by reference to the notion of materiality. The general understanding of materiality stresses the opinion of stakeholders about the company as a pivotal factor for the content of sustainability reports. The analysis of SeaBOS showed that transparency is indispensable for the exercise and development of stewardship strategies but should be informed by science and respond to the needs of biosphere resilience and planetary boundaries. Exploring the requirements and redefinition of materiality for reporting biosphere stewardship is necessary. 2) Reconsidering the notion of stakeholder: the definition of stakeholders assumes that stakeholders have agency over the company. Stewardship includes more diverse, intergenerational, and non-human “stakeholders” than accountability. SeaBOS showed that relationships with local communities are not built bidirectional: they are not considered partners for sustainability challenges, while the scientists’ articulation of stewardship points to the need to engage with artisanal fishers, women, indigenous peoples, etc. in transforming the narratives of the ocean. Equity is a functional driver for biosphere resilience, while current definitions of stakeholder do not include it. Stakeholder approaches based on f interest generate tensions with the dimension of care (a key point in the stewardship normative agenda). Stakeholder articulations need to be developed to respond to stewardship. 3) New narratives in accounts for the Anthropocene: the progress report built by SeaBOS follows a different and innovative format but shares with the companies’ CSR reports the portrayal of only positive actions and results, not discussing where performance should be improved or where ambitions are not up to science-based standards. SeaBOS showed examples of companies starting to be transparent in cases of low performance. Scientists state that transparency in cases of low performance needs to be rewarded instead of punished. Modern narratives that only underline successes need to be overcome and substituted with new narratives that are informative of the dynamics that need to be changed to safeguard the biosphere’s resilience. The concept of boundary objects is directly related to the resolution of complex problems in the absence of consensus. These scenarios are likely to increase in the biosphere in crisis and enable the analysis of dynamics by which articulations can reconcile for cooperation and sustainability in the Anthropocene. The last research study is a decolonial analysis of corporate biosphere stewardship. The insights derived from the analysis of SeaBOS employing the decolonial Sociology of Absences and Emergences are articulated into five propositions: 1) The role of science: ecological literacy is necessary for addressing the interplay between accounting and nature. From a decolonial perspective, the value of scientific knowledge is recognized while it advocates for more dynamic understandings of reality, avoiding totalities and valuing alternative sources of knowledge. This perspective corresponds to the scientific position found in SeaBOS, recommending the inclusion of local knowledge and traditional values into approaches to ecosystem management. The role of science raises the challenge of developing accounting technologies which make an ecology of knowledge(s) visible. 2) The axiology of care: care is a key element in the theorization of stewardship and decoloniality. Central in sustainability accounting is the notion of development, which is questioned from both decolonial and ecological perspectives. Development entails a linear understanding of time and progress, while it stands on increased levels of material consumption. Substituting development with the axiology of care is a means of decolonializing accounting while acting in the present to produce concrete alternatives for a more sustainable future. 3) The need for equity and recognition: accounting plays a key role in producing visibilities and reproducing rationalities. While equity occupies a relevant dimension in the scientific articulation of stewardship, as it is not formalized into a traceable commitment, it becomes produced as in existent across corporate accounts. The ecology of recognition requires that differences are accounted for and made visible and recognized as equal. 4) The global/local tension: While ocean stewardship requires a global perspective, local experiences are equally relevant and usually end up produced as inexistent. However, local diversity is indispensable for resilience on ecological and social terms, and therefore accounts should be aware of the need to preserve the wealth of human experience with the inclusion of local considerations. 5) The definition of value: accounting for stewardship should differentiate between conceptualizations of value, expanding the notion of productivity to include social and ecological productivity. Such accounting would be able to distinguish productivity from extractivism, mobilizing an ecology of productivity(ies). Decolonializing the notion of productivity would enhance the value(s) of the biosphere
Una propuesta para la experimentación en el laboratorio y análisis del efecto de una práctica de laboratorio en alumnos de 1º de Bachillerato
No full textLas prácticas de laboratorio constituyen una herramienta de gran utilidad en la didáctica de
ciencias experimentales, como Biología y Geología. El uso del laboratorio proporciona una
gran cantidad de beneficios al alumnado, puesto que rompe la brecha existente entre teoría y
práctica y muestra aplicaciones reales. A la vista de la nueva ley de educación, LOMLOE,
centrada en la adquisición de competencias y habilidades, el laboratorio se antoja como un
modelo didáctico esencial para transmitir experiencias variadas al alumnado.
En el presente Trabajo de Fin de Máster, se proponen siete prácticas representativas de todos
los bloques de saberes básicos establecidos en el currículo de la materia de Biología, Geología
y Ciencias Ambientales de 1º de Bachillerato. Además, se muestra un estudio efectuado con
tres grupos de alumnos para determinar la contribución de una práctica sobre hormonas
vegetales al aprendizaje del alumnado. Los resultados de los cuestionarios efectuados al inicio
y al final de la intervención, muestran una mejoría general de los conocimientos y las
competencias desarrolladas por el alumnado, permitiendo comprobar la efectividad del trabajo
práctico en este contexto.Laboratory experiences are a very useful tool in experimental sciences education, such as
Biology and Geology. The use of laboratory provides a great number of benefits for students,
as it breaks the gap between theory and practice, and it shows real life applications. In view of
the new education law, LOMLOE, which focuses on the acquisition of competences and skills,
the laboratory seems to be an essential didactic model for providing a wide range of experiences
to students.
In this project, seven practices are proposed which include all the basic knowledge blocks
established in the curriculum of the subject Biology, Geology and Environmental Sciences in
the first year of Bachillerato. In addition, a study carried out with three groups of students in
this course is shown in order to determine the contribution of a practice on phytohormones to
of such student learning. The results of the tests made at the beginning and in the end of the
activity show a general improvement in the knowledge and skills developed by the students,
showing the effectiveness of practical work in this situation
El álbum ilustrado como recurso educativo para fomentar la escritura creativa: una propuesta didáctica en el aula de lengua castellana y literatura
Get PDFEscribir es una de las cuatro habilidades que integran la competencia comunicativa por lo que
resulta fundamental para el desarrollo integral de las personas. Los alumnos de Educación
Secundaria suelen sentirse alejados de la literatura y la creación literaria, de forma que es
preciso explorar diferentes vías para despertar su interés y contribuir a la mejora de su
comprensión y expresión escrita. En este trabajo se ha realizado una revisión teórica sobre la
situación de la escritura creativa en las aulas, la metodología del taller de escritura y el álbum
ilustrado como recurso didáctico capaz de potenciar la creatividad. En base a los fundamentos
teóricos analizados, se ha diseñado una propuesta didáctica que pretende mejorar la expresión
desde la motivación e interés personal de los alumnos. Para ello, se han diseñado actividades
que se enmarcan en un taller de escritura creativa en torno al álbum ilustrado.Writing is one of the four skills that make up communicative competence, so it is fundamental
for the integral development of people. Secondary Education students often feel distant from
literature and literary creation, so it is necessary to explore different ways to awaken their
interest and contribute to the improvement of their written comprehension and expression. In
this work, a theoretical review has been carried out on the situation of creative writing in the
classroom, the methodology of the writing workshop and the picture book as a didactic
resource capable of enhancing creativity. Based on the theoretical foundations analysed, a
didactic proposal has been designed that aims to improve the expression from the motivation
and personal interest of the students. For this, the activities designed are part of a creative
writing workshop around the picture book
Scaled concrete beams containing maximum levels of coarse recycled aggregate: Structural verifications for precast‐concrete building applications
Get PDFThe use of Recycled aggregate (RA) enhances concrete sustainability. If used on an industrial-scale, structural verification, and testing will be required to confirm that RA concrete can meet relevant industrial standards and the requirements of manufacturers, especially in the precast-concrete industry. In this paper, an experimental campaign with the participation of a precast-concrete manufacturer is reported. The objective is to test a self-compacting concrete (SCC) mix, designed for structural applications, that contains maximum amounts of 100% coarse RA, in order to establish its compliance with the habitual requirements of precast-concrete manufacturers. Thus, scaled beams (12 × 24 × 180 and 24 × 24 × 130 cm) were subjected to bending, shear-bending, shear, and long-term-deflection tests. In addition, the performance of that SCC mix in the bending and shear-bending tests was compared with the performance of an SCC mix of similar compressive strength containing 0% coarse RA. In the failure tests, the experimental results were between 1.5 and 3 times higher than the required values. The elastic behavior of both SCC mixes was also very similar in those tests, regardless of the amount of coarse RA, due to the robust design of the water and superplasticizer content of the SCC, which balanced the decreased flowability and the lower compressive strength of SCC that resulted from the additions of coarse RA. The SCC mix with 100% RA showed a lower load-bearing capacity after failure and narrow compliance margins with the deflection limits of the long-term-deflection test. Even though the SCC mix with 100% RA met all the standard technical specifications of the precast-concrete manufacturer, reference should always be made to the serviceability limit states that are applicable at the time of the structural design phaseThis research work was supported by the Spanish Ministry of Universities, MICINN, AEI, EU, ERDF, and NextGenerationEU/PRTR (grant numbers PID2020-113837RB-I00; doi:10.13039/501100011033; TED2021-129715B-I00; FPU17/03374); the Junta de Castilla y León (Regional Government) and ERDF (grant number UIC-231); and, finally, the University of Burgos (grant number SUCONS, Y135.GI). Finally, the support and assistance of ARTEPREF S.A. for the development of this study is also highly appreciated and valued
Thermophysical Study on the Mixing Properties of Mixtures Comprising 2-(2-Methoxyethoxy)ethanol, Butan-1-ol, Butan-2-ol, and Propan-1-ol
Get PDFExcess enthalpy (HE), dynamic and kinematic viscosities (η, υ), density (ρ), and refractive index (nD) of mixtures comprising 2-(2-methoxyethoxy)ethanol, butan-1-ol, butan-2-ol, and propan-1-ol are presented at p = 0.1 MPa and at T = 298.15 and 313.15 K. Deviations in refractive index (ΔnD) is generated from experimental data of refractive index. Experimental data of ρ for all binary mixtures are predicted using the PC-SAFT (Perturbed Chain-Statistical Associating Fluid) EoS. Furthermore, HE and ΔnD are adjusted using the Redlich–Kister equation. However, the correlation of measured data of HE is performed by using the UNIQUAC and NRTL models
Flexural fatigue of high-strength plain and fiber-reinforced concrete: influence of mesostructure and study of size effect
Get PDFEqual fatigue tests in concrete, meaning those performed on exactly equal or
homothetic specimens subjected to the same stress levels, present two problems yet to be
solved. On the one hand, the high dispersion of the results, which causes the fatigue life
in two apparently identical elements to vary by up to two or more orders of magnitude.
On the other hand, the size effect, whereby fatigue strength decreases with increasing
element size.
The aim of this research work is to study these two issues in depth. Regarding the first
one, the influence of the dispersion of concrete mesostructure on the dispersion of fatigue
results will be studied; in particular, it will be evaluated whether the stochastic
arrangement of fibers (in fiber concrete) or pores (in plain concrete) explains the
variability of fatigue life. As for the size effect, fatigue tests will be performed on
geometrically similar specimens subjected to the same equivalent stress levels.
Macroscopic damage indicators, such as crack opening, will be used to determine the
magnitude of the size effect and its variation according to the type of concrete (plain
concrete and fiber-reinforced with different fiber contents).
The results reveal that the arrangement of fibers and pores varies significantly in
apparently identical specimens, and that this partly explains the dispersion of fatigue
results. However, the estimation of the fatigue response of concrete from its
mesostructure requires complex models, comprising several geometrical parameters of
various components. In this work, a methodological approach to the problem is made,
proposing mesostructure parameters that are reasonably predictive. With respect to the
size effect, it is observed that the presence of fibers reduces the size effect on fatigue life,
almost nullifying it. Furthermore, it is concluded that the secondary crack opening rate
(dCMOD/dn) is an adequate parameter to explain the fatigue life in general, and the size
effect in particular.Los ensayos de fatiga en hormigón iguales, entendiéndose como tales, los realizados
en probetas exactamente iguales u homotéticas sometidas a los mismos niveles de
tensiones, presentan dos problemáticas aún por resolver. Por un lado, la elevada
dispersión de los resultados, que provoca que la vida a fatiga en dos elementos
aparentemente idénticos pueda variar hasta en dos o más órdenes de magnitud. Por otro
lado, el efecto tamaño, por el cual la resistencia a fatiga disminuye con el aumento del
tamaño del elemento.
En este trabajo de investigación se pretende profundizar en el estudio de estas dos
cuestiones. Con respecto a la primera, se va a estudiar la influencia de la dispersión de la
mesoestructura del hormigón en la dispersión de los resultados de fatiga; en particular, se
evaluará si la disposición estocástica de las fibras (en hormigón con fibras) o de los poros
(en hormigón en masa) explica la variabilidad de la vida a fatiga. En cuanto al efecto
tamaño, se realizarán ensayos de fatiga en probetas geométricamente similares sujetas a
los mismos niveles de tensión equivalente. A través de indicadores macroscópicos de
daño, como la apertura de fisura, se determinará la magnitud del efecto tamaño y su
variación en función del tipo de hormigón (en masa y con diferentes contenidos de fibras).
Los resultados revelan que la disposición de las fibras y los poros varía
significativamente en probetas aparentemente idénticas, y que esto explica en parte la
dispersión de los resultados de fatiga. No obstante, la estimación de la respuesta en fatiga
del hormigón a partir de su mesoestructura requiere de modelos complejos, que
comprendan varios parámetros geométricos de diversos componentes. En este trabajo se
realiza una aproximación metodológica al problema, proponiendo parámetros de la
mesoestructura que son razonablemente predictivos. Con respecto al efecto tamaño, se
observa que la presencia de fibras reduce el efecto tamaño en la vida fatiga, hasta
prácticamente anularlo. Además, se concluye que la tasa de apertura de fisura secundaria
(dCMOD/dn) es un parámetro adecuado para explicar la vida a fatiga en general, y el
efecto tamaño en particular