Racionalización energética en instalaciones hoteleras: análisis para un nuevo proyecto técnico basado en la "cogeneración", mediante la optimización de las curvas de demanda

Estudio de la aplicación de la "cogeneración" en el subsector hotelero y su repercusión positiva en la racionalización energética. Se estructura y desarrolla un modelo físico-matemático desde el estudio y análisis de una población hotelera real en el área de Canarias. Se crea y aporta un modelo informático de trabajo que permite la simulación del comportamiento de los parámetros técnicos hoteleros. Se introduce, como complemento, el frio por absorción y la obtención de agua sanitaria por desalación de agua de mar. Se analiza el comportamiento tanto de plantas con turbina de gas como con motores alternativos de combustión interna, para lo que se desarrollan los correspondientes modelos informáticos, con los que se puede simular diversas opciones de plantas de cogeneración, estableciendo comparación con las instalaciones convencionale

Intragranular carbon nanotubes in alumina-based composites for reinforced ceramics

The traditional methods for the synthesis of reinforced alumina-based matrix composites with carbon nanotubes (CNTs) have presented serious difficulties for obtaining well-dispersed and homogeneously distributed CNTs within the matrix. Besides this, the CNTs are typically found in the grain boundaries of the matrix. These features involve a non-optimal reinforcement role of the CNTs. With the aim of maximizing the efficiency of the reinforcement of the CNT, this work reconsiders a sol-gel-based procedure for ceramic composite fabrication with a two fold objective: to achieve a good dispersion of the CNTs and to promote the intragranular location of the CNTs. The mixing of precursors and CNTs has been developed under the presence of high-power ultrasounds, followed by a rapid in-situ gelation that “froze” the nanotubes inside the gel. The chemical and physical relationships between the ceramic matrix and the embedded reinforcing phase have been researched. First results confirm the success of the synthesis procedure for the preparation of alumina-based composite powders starting from a commercial boehmite sol and multiwalled carbon nanotubes. X-ray diffraction and Raman analyses confirmed the formation of the α-Al 2 O 3 and the persistence of the non-damaged nanotube structure. N 2 physisorption and electron microscopy were used to check the evolution of the nanostructure and to confirm the presence of intragranular carbon nanotube within the polycrystalline powder. Therefore, the alumina-based composite powder prepared by this new procedure is a good candidate for the preparation of reinforced ceramic matrix composites.Junta de Andalucía P12-FQM-107

Optimización del proceso de desescarche en una instalación frigorífica

En este trabajo de fin de grado se estudia la generaci´on de escarcha en el evaporador de una c´amara frigor´ıfica. Para ello, se ha registrado, en intervalos de un minuto durante 24 horas, la temperatura y humedad relativa del aire a la entrada y salida del evaporador. Posteriormente, se han calculado diversos par´ametros del aire h´umedo, para determinar la cantidad de hielo generado. Una vez conocida la cantidad de hielo generado, se ha calculado el tiempo necesario para su fusi´on, teniendo en cuenta la potencia de las resistencias el´ectricas instaladas en el evaporador. Finalmente, se han establecido alternativas a la temporalizaci´on y a la potencia necesaria en las resistencias el´ectricas, proponiendo soluciones m´as eficientes tanto desde el punto de vista energ´etico como econ´omico.In this final-degree project, the generation of frost over the evaporator of a cold room will be studied. To do this, the temperature and relative humidity of the air at the inlet and outlet of the evaporator have been recorded at one-minute intervals for a period of up to 24 hours. Subsequently, to determine the amount of ice produced from the most air, several parameters have been calculated. Once the amount of ice generated is known, the time necessary for its melting has been calculated, taking into account the power of the electric heaters installed in the evaporator. Finally, alternatives to temporalization and the necessary power in electrical heaters have been established, proposing more efficient solutions both from an energy and economic point of view

Alport Syndrome and Femtosecond Laser Assisted Cataract Surgery

We report the surgical management of a patient with bilateral anterior lenticonus due to Alport syndrome using femtosecond laser-assisted cataract surgery (FLACS) and the Optiwave Refractive Analysis (ORA) system. A 38-year-old man with Alport syndrome presented to our department with visual loss due to anterior lenticonus in both eyes. Adjustments during bilateral FLACS were performed with the software’s calipers to manually delineate the anterior capsulotomy. Multifocal toric intraocular lenses (IOLs) were selected and placed in the posterior chamber with the aid of intraoperative aberrometry. The intended postoperative positioning parameters for the IOL as well as the planned visual acuity and refraction were achieved. The implementation of FLACS and intraoperative wavefront aberrometry is a safe and useful surgical approach for the management of cataract in challenging cases such as patients with anterior lenticonus due to Alport syndrome

Evaluation of the photocatalytic activity and anticorrosion performance of electrospun fibers doped with metallic oxides

This paper reports the development and characterization of a multifunctional coating that combines anticorrosion and photocatalytic properties, deposited by means of the electrospinning technique. In the first step, a functional electrospun fiber mat composed of poly(acrylic acid) (PAA) and β-cyclodextrin (β-CD) was obtained, showing high water insolubility and great adhesion increased by means of a thermal crosslinking process (denoted as PAA + β-CD). In the second step, the fibers were doped with particles of titanium dioxide (denoted as PAA + β-CD/TiO2) and titanium dioxide plus iron oxide (denoted as PAA + β-CD/TiO2/Fe2O3). The morphology and fiber diameter of the electrospun mats were evaluated by using confocal microscopy, whereas the presence of the metal oxides in the electrospun fibers was corroborated by scanning electron microscopy (SEM) and X-ray fluorescence (XRF), respectively. In addition, electrochemical tests in saline solution revealed that the sample composed of PAA + β-CD/TiO2/Fe2O3 showed the highest corrosion protection efficiency of all the samples, which was directly associated to lower corrosion current density and higher corrosion potential. Furthermore, the paper reports a novel approach to in situ determination of methylene blue (MB) degradation onto the coating. The results revealed complete degradation of MB, which is perfectly appreciated by total discoloration of the film in the irradiated zone (from bluish to a white spot). The main conclusions of this research are the efficiency of the electrospun system PAA + β-CD/TiO2/Fe2O3 for developing photocatalytic activity and corrosion protection and the utility of the dry MB discoloration tests to evaluate photocatalytic activity.This research was funded by the Government of Navarra-Department of Economic Development (Project ARGITU) and by the Public University of Navarre (Project PJUPNA1929)

Advanced Surface Treatments for Improving the Biocompatibility of Prosthesis and Medical Implants

During the last two decades, numerous surface treatments have been developed to improve the biocompatibility of different types of prosthesis and other medical implants. Some of these devices are subject to demanding loading and friction conditions (e.g., hip, knee, and spine prosthesis). However, for other implants, there are more specific requirements as it happens for coronary stents or pacemaker electrodes. The materials used for the manufacture of the aforementioned devices are subjected to very high restrictions in terms of biocompatibility, in particular on chemical composition, corrosion resistance, or ion release. As a consequence, most of prosthesis and other implants are made of a limited number of materials such as titanium alloys, stainless steels, cobalt-chromium alloys, UHMWPE, or PEEK. Unfortunately, from a strict point of view, none of these materials meet all the requirements that would be desirable in terms of durability and prevention of infections and inflammatory processes. Coatings and other surface treatments have been developed to solve these problems and to improve biocompatibility. In this chapter, we present an updated review of the most used surface engineering technologies for biomaterials, like novel PVD coatings, ion implantation, and other plasma spray treatments, as well as a critical review of the characterization techniques. This study is completed with an insight into the future of the field

Reactive SPS for sol–gel alumina samples: Structure, sintering behavior, and mechanical properties

This work presents a fast and direct controlled routine for the fabrication of fully dense alumina based on the reactive spark plasma sintering (reactive-SPS) of boehmite (γ-AlOOH) nano-powders obtained by the sol–gel technique. The evolution of the transition aluminas during sintering has been studied. Some boehmite powders were seeded with α-Al2O3 particles prior to the gelation. Boehmite seeded powders exhibited a direct transition to α-Al2O3 at 1070 °C, enhancing the transformation kinetics and lowering the required temperature by more than 100 °C. For comparison, other samples were prepared by previously annealing the seeded and unseeded boehmite powders. Thus, α-Al2O3 powders were obtained and were sintered by standard-SPS. A detailed structural and mechanical characterization is presented, comparing the hardness and indentation fracture resistance for different grain sizes and porosities. Both the reactive-SPSed samples and the standard-SPSed samples showed a high hardness (18–20 GPa), whereas the reactive-SPSed samples exhibited a lower indentation fracture resistance due to a large grain size (∼10 μm). Improvements of this procedure for obtaining smaller grain size are discussed. In summary, the presented technique brings a revolutionary fast method for the fabrication of fully dense alumina, as this process reduces the time and temperature required for alumina densification.Ministerio de Ciencia e Innovación PGC2018-094952-B-I00Junta de Andalucía P12- FQM-1079, FQM393Universidad de Sevilla PGC2018-094952-B-I00Junta de Extremadura GR1808

Designing multifunctional protective PVC electrospun fibers with tunable properties

In this work, the electrospinning technique is used for the fabrication of electrospun functional fibers with desired properties in order to show a superhydrophobic behavior. With the aim to obtain a coating with the best properties, a design of experiments (DoE) has been performed by controlling several inputs operating parameters, such as applied voltage, flow rate, and precursor polymeric concentration. In this work, the reference substrate to be coated is the aluminum alloy (60661T6), whereas the polymeric precursor is the polyvinyl chloride (PVC) which presents an intrinsic hydrophobic nature. Finally, in order to evaluate the coating morphology for the better performance, the following parameters-such as fiber diameter, surface roughness (Ra, Rq), optical properties, corrosion behavior, and wettability-have been deeply analyzed. To sum up, this is the first time that DoE has been used for the optimization of superhydrophobic or anticorrosive surfaces by using PVC precursor for the prediction of an adequate surface morphology as a function of the input operational parameters derived from electrospinning process with the aim to validate better performance.This research was funded by the Ministerio de Ciencia, Innovación y Universidades-Retos (Project RTI2018-096262-B-C41-MAITAI, Multidisciplinary Approach for the Implementation of new Technologies to prevent Accretion of Ice on aircraft), and by the Public University of Navarre (Project PJUPNA1929).This research was funded by the Ministerio de Ciencia, Innovaci?n y Universidades-Retos (Project RTI2018-096262-B-C41-MAITAI, Multidisciplinary Approach for the Implementation of new Technologies to prevent Accretion of Ice on aircraft), and by the Public University of Navarre (Project PJUPNA1929)