1,099 research outputs found
Tipificación de Solanum (Solanaceae), especie descrita por Martín de Sessé y Lacasta y José Mariano Mociño
No full textSe confirman o designan los lectótipos, neótipos o epítipos de 16 de los 22 nombres acuñados por Martín de Sessé y Lacasta y José Mariano Mociño que o bien fueron descritos dentro del género Solanum (Solanaceae) o son actualmente reconocidos como parte del mismo): Solanum bifidum, S. cordovense, S. declinatum, S. dichotomum, S. diphyllum, S. lanceifolium, S. lanceolatum, S. lineatum (ambos homónimos), S. longifolium, S. mexicanum, S. nutans, S. sarmentosum, S. scandens, S. tlacotalpense y S. uniflorum. Se incluye una breve introducción explicando la importancia de la Real Expedición Botánica a Nueva España (expedición de Sessé y Mociño) para la botánica de su tiempo, así como las dificultades que entraña neotipificar o lectotipificar los nombres acuñados por éllos. Se incluye el nombre aceptado para cada taxon cuando es posible y cada tipificación se acompaña de una discusión explicando la elección de los especímenes. Todos los tipos nuevos se acompañan de una foto
Determination of important agronomical and quality characters in silage maize cultivars
No full textBu araştırma, 2006 yılında Konya ekolojik şartlarında, at dişi mısır çeşitlerinin silaj verimi ve kalite ile ilgili özelliklerinin incelenerek, bu ekolojiye uygun yüksek verimli ve kaliteli silaj mısır çeşitlerini belirlemek amacıyla yürütülmüştür. ?Tesadüf Blokları? deneme desenine göre üç tekerrürlü olarak kurulan bu araştırmada, 24 at dişi mısır çeşidi kullanılmıştır. Araştırmada silaj verimleri 6795 kg /da (CP-81) ? 10348 kg/da (Lacasta), bitki boyları 298 cm (Lacasta) ? 341 cm (CP-91), bitki ağırlıkları 851 g ( CP-81) -1444 g (CP-91), yaprak sayıları 13.00 adet (Lacasta, ZP-677) ? 18.46 adet (CP-91), yaprak alanları 716.93 cm² (Cadiz) ? 965.41 cm² (CP-91) , yaprak oranları %12.7 (ZP-677) ? %20.5 (CP-91), yaprak ağırlıkları 126.33 g (ZP-677) ? 297.66 g (CP-91) , yaprak genişlikleri 10.70 cm (OSKK-644) ? 12.86 cm (C-955) , yaprak uzunlukları 81.73 cm (Cadiz) ? 108.16 cm (Arifiye) , sap ağırlıkları 394.00 g (Ada- 523) - 699.33 g (Arifiye), sap çapları 22.89 mm ( Turtop) ? 29.62 mm (CP-91), sap oranları % 44.93 (Lacasta) - %56.20 (Arifiye) , ilk koçan yükseklikleri 114.40 cm (Lacasta) ? 187.33 cm (Arifiye) , koçan ağırlıkları 282.33 g (CP-81) ? 453.66 g (CP-91) , koçan oranları % 28.6 (Arifiye) - % 38.2 (DKC-6842) , kuru madde verimleri 1998 kg/da (CP81) ? 3028 kg/da (King) , kuru madde oranları % 24.40 (P-31Y43) - % 32.10 ( OSSK-659) , protein oranları % 4.68 ( Lacasta) - % 6.87 (CP-81) arasında değişmiştir. Bu araştırma sonucunda ?Lacasta?, ?Dracma?, ?C-955?, ?CP-91?, ?King?, ``Truva'', ``Doge'', ``Dako-743'' çeşitleri verim ve kalite yönünden Konya ekolojik şartlarında yetiştirilebilecek uygun silaj mısır çeşitleri olarak ön plana çıkmışlardır.This research has been conducted to determine the silage maize cultivars can be grown for silage yield grain and quality under Konya ecological conditions, examining the silage yield and quality components of maize cultivars in 2006. In this research which arranged in the ? Randomized Complete Blocks Experimental Design? with three replications, and 24 dent corn cultivars were used as material In this research, has been changed silage yield, from 6795 kg /da (CP-81) to 10348 kg/da (Lacasta), plant height from 298 cm (Lacasta) to 341 cm (CP-91), plant weight from 851 g ( CP-81) to 1444 g (CP-91), leaf number from 13.00 (Lacasta , ZP-677) to 18.46 (CP-91), leaf area from 716.93 cm² (Cadız) to 965.41 cm² (CP-91), leaf percent from 12.7 % (ZP-677) to 20.5 % (CP-91), leaf weight from 126.33 g (ZP-677) to 297.66 g (CP-91), leaf width from 10.70 cm (OSKK-644) to 12.86 cm (C-955), leaf lenght from 81.73 cm (Cadız) to 108.16 cm (Arifiye), stem weight from 394 g (Ada- 523) to 699.33 g (Arifiye), stem diameter from 22.89 mm ( Turtop) to 29.62 mm(CP-91), stem percent from 44.93 % (Lacasta) to 56.20 % (Arifiye), first ear height from 114.40 cm (Lacasta) to 187.33 cm (Arifiye), ear weight from 282.33 g (CP-81) to 453.66 g (CP-91), ear percent from 28.6 % (Arifiye) to 38.2 % (DKC-6842), dry matter yield from 1998 kg/da (CP-81) to 3028 kg/da (King), dry matter rate from 24.40 % (P-31Y43) to 32.10 % (OSSK-659), protein rate from 4.68 % (Lacasta) to 6.87 % (CP-81). In this research was recommended that ?Lacasta?, ?Dracma?, ?C-955?, ?CP-91??, ?King?,``Truva??, ``Doge??, ``Dako-743??, maize varieties can be grown for high silage yield and quality under Konya ecological conditions
Performance of VATA64HDR16 ASIC for medical physics applications based on continuous crystals and SiPMs
No full text[EN] Detectors based on Silicon Photomultipliers (SiPMs) coupled to continuous crystals are being tested in medical physics applications due to their potential high resolution and sensitivity. To cope with the high granularity required for a very good spatial resolution, SiPM matrices with a large amount of elements are needed. To be able to read the information coming from each individual channel, dedicated ASICs are employed. The VATA64HDR16 ASIC is a 64-channel, charge-sensitive amplifier that converts the collected charge into a proportional current or voltage signal. A complete assessment of the suitability of that ASIC for medical physics applications based on continuous crystals and SiPMs has been carried out. The input charge range is linear from 20 pC up to 55 pC. The energy resolution obtained at 511 keV is 10% FWHM with a LaBr3 crystal and 16% FWHM with a LYSO crystal. A coincidence timing resolution of 24 ns FWHM is obtained with two LYSO crystals.This work was supported in part by the European Commission's 7th Framework Programme through the ENVISION project (G. A. num 241851), by the Spanish Ministerio de Economia y Competitividad (FPA2014-53599-R), the UVEG (UV-INV-PRECOMP12-80755) and the Generalitat Valenciana (GV/2013/133 and GVISIC/2012/020). Group members are supported by Ramon y Cajal, UVEG Atraccio de Talent and Generalitat Valenciana contracts.Barrio-Toala, John;Etxebeste, A.;Lacasta, C.;Muñoz, E.;Oliver-Guillén, José Francisco;Solaz, C.;Llosá, G. (2015). Performance of VATA64HDR16 ASIC for medical physics applications based on continuous crystals and SiPMs. Journal of Instrumentation. 10. https://doi.org/10.1088/1748-0221/10/12/P12001S10Llosá, G., Barrio, J., Lacasta, C., Bisogni, M. G., Guerra, A. D., Marcatili, S., Barrillon, P., Bondil-Blin, S., de la Taille, C., & Piemonte, C. (2010). Characterization of a PET detector head based on continuous LYSO crystals and monolithic, 64-pixel silicon photomultiplier matrices. Physics in Medicine and Biology, 55(23), 7299-7315. https://doi.org/10.1088/0031-9155/55/23/008Seifert, S., van Dam, H. T., Huizenga, J., Vinke, R., Dendooven, P., Löhner, H., & Schaart, D. R. (2012). Monolithic LaBr3:Ce crystals on silicon photomultiplier arrays for time-of-flight positron emission tomography. Physics in Medicine and Biology, 57(8), 2219-2233. https://doi.org/10.1088/0031-9155/57/8/2219Powolny, F., Auffray, E., Brunner, S. E., Garutti, E., Goettlich, M., Hillemanns, H., Jarron, P., Lecoq, P., Meyer, T., Schultz-Coulon, H. C., Shen, W., & Williams, M. C. S. (2011). Time-Based Readout of a Silicon Photomultiplier (SiPM) for Time of Flight Positron Emission Tomography (TOF-PET). IEEE Transactions on Nuclear Science, 58(3), 597-604. https://doi.org/10.1109/tns.2011.2119493Blin, S., Barrillon, P., & de La Taille, C. (2010). MAROC, a generic photomultiplier readout chip. IEEE Nuclear Science Symposuim & Medical Imaging Conference, 1690-1693. https://doi.org/10.1109/nssmic.2010.5874062Raux, L., Callier, S., Conforti di Lorenzo, S., Dulucq, F., de La Taille, C., Martin-Chassard, G., & Seguin-Moreau, N. (2012). SPIROC: Design and performance of a dedicated very front-end for an ILC prototype Hadronic Calorimeter with SiPM. 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC), 557-561. https://doi.org/10.1109/nssmic.2012.6551170Argentieri, A., Corsi, F., Foresta, M., Marzocca, C., & Del Guerra, A. (2011). Design and characterization of CMOS multichannel front-end electronics for silicon photomultipliers. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 652(1), 516-519. https://doi.org/10.1016/j.nima.2010.08.067Meier, D., Mikkelsen, S., Talebi, J., Azman, S., Mahlum, G., & Patt, B. E. (2010). An ASIC for SiPM/MPPC readout. IEEE Nuclear Science Symposuim & Medical Imaging Conference, 1653-1657. https://doi.org/10.1109/nssmic.2010.5874056Rolo, M. D., Bugalho, R., Gonçalves, F., Mazza, G., Rivetti, A., Silva, J. C., Silva, R., & Varela, J. (2013). TOFPET ASIC for PET applications. Journal of Instrumentation, 8(02), C02050-C02050. https://doi.org/10.1088/1748-0221/8/02/c02050Cabello, J., Barrillon, P., Barrio, J., Bisogni, M. G., Del Guerra, A., Lacasta, C., Rafecas, M., Saikouk, H., Solaz, C., Solevi, P., de La Taille, C., & Llosá, G. (2013). High resolution detectors based on continuous crystals and SiPMs for small animal PET. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 718, 148-150. https://doi.org/10.1016/j.nima.2012.08.094Development of a three layer Compton telescope prototype based on continuous LaBr<inf>3</inf> crystals and Silicon Photomultipliers. (2013). 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC), 1-3. https://doi.org/10.1109/nssmic.2013.6829049Data acquisition system for the readout of SiPM arrays. (2013). 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC), 1-4. https://doi.org/10.1109/nssmic.2013.6829735Bagliesi, M. G., Avanzini, C., Bigongiari, G., Cecchi, R., Kim, M. Y., Maestro, P., Marrocchesi, P. S., & Morsani, F. (2011). A custom front-end ASIC for the readout and timing of 64 SiPM photosensors. Nuclear Physics B - Proceedings Supplements, 215(1), 344-348. https://doi.org/10.1016/j.nuclphysbps.2011.04.049Llosá, G., Barrio, J., Cabello, J., Crespo, A., Lacasta, C., Rafecas, M., Callier, S., de La Taille, C., & Raux, L. (2012). Detector characterization and first coincidence tests of a Compton telescope based on LaBr3 crystals and SiPMs. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 695, 105-108. https://doi.org/10.1016/j.nima.2011.11.04
Minimising activity and dose with enhanced image quality by radiopharmaceutical administrations
No full textOwing to the introduction of new diagnostic procedures, such as computed tomography (CT), positron emission tomography (PET) and single photon emission computed tomography (SPECT), the individual dose caused by medical exposures has grown rapidly in the last years. This is especially a subject to radiation protection for nuclear medical diagnosis, since in this case radiopharmaceuticals are administered to the patient, meaning not only a radiation exposure to the diseased tissue but also to the healthy tissues of large parts of the body. 'Minimizing Activity and Dose with Enhanced Image quality by Radiopharmaceutical Administrations' (MADEIRA) is a project cofunded by the European Commission within the Seventh Euratom Framework Programme that aims to improve three-dimensional (3D) nuclear medical imaging technologies significantly. MADEIRA is aiming to improve the efficacy and safety of 3D PET and SPECT functional imaging by optimising the spatial resolution and the signal-to-noise ratio, improving the knowledge of the temporal variation of the radiopharmaceuticals' uptake in and clearance from tumourous and healthy tissues, and evaluation of the corresponding patient dose. Using an optimised imaging procedure that improves the information gained per unit administered dose, MADEIRA aims especially to reduce the dose to healthy tissues of the patient. In this paper, an overall summary of the current achievements will be presented
Disseny d un carro per a emmagatzematge de pilotes i altres articles d'esport per a ús en centres educatius
No full text[ES] Para llevar a cabo este trabajo se ha realizado un estudio de mercado de productos similares,
encuestas a distintos grupos de usuarios, análisis de ensamblaje, fabricación y viabilidad.
También se han realizado cálculos de resistencia, así como un prototipo de uno de los
componentes del carro. Se han realizado planos y cálculos de presupuesto y mediciones del
producto. Como documentación para acompañar al producto se ha diseñado desde las
instrucciones de montaje del producto, hasta el formato de una página web, tarjeta informativa,
tríptico, etc.[EN] To carry out this work, a market study of similar products, surveys of different user groups,
assembly, manufacturing and feasibility analysis have been carried out. Resistance calculations
have also been made, as well as a prototype of one of the car's components. Plans and budget
calculations and measurements of the product have been made. As documentation to
accompany the product, it has been designed from the assembly instructions of the product, to
the format of a web page, information card, triptych, etc.[CA] Per fer aquest treball s'ha realitzat un estudi de mercat de productes similars, enquestes a
diferents grups d'usuaris, anàlisi d'acoblament, fabricació i viabilitat. També s'han fet càlculs de
resistència, així com un prototip d'un dels components del carro. S'han realitzat plànols i càlculs
de pressupost i amidaments del producte. Com a documentació per acompanyar el producte
s'ha dissenyat des de les instruccions de muntatge del producte fins al format d'una pàgina web,
targeta informativa, tríptic, etc.Lacasa Lacasta, C. (2023). Diseño de un carro para almacenamiento de balones y otros artículos de deporte para su uso en centros educativos. Universitat Politècnica de València. https://riunet.upv.es/handle/10251/200845TFG
Corn pith as insulating biomaterial: from biomass fractionation to composite production
No full textMayer-Laigle C., Haurie Ibarra L., Palumbo M., Breysse A., Mabille F., Lacasta A. and Barron C. (2017). Corn pith as insulating biomaterial: from biomass fractionation to composite production. 4th International Conference on Biobased Materials and Composites, Nantes, 29-31 March. Mayer-Laigle C., Haurie Ibarra L., Palumbo M., Breysse A., Mabille F., Lacasta A. and Barron C. (2017). Corn pith as insulating biomaterial: from biomass fractionation to composite production. 4th International Conference on Biobased Materials and Composites, Nantes, 29-31 March.Mayer-Laigle C., Haurie Ibarra L., Palumbo M., Breysse A., Mabille F., Lacasta A. and Barron C. (2017). Corn pith as insulating biomaterial: from biomass fractionation to composite production. 4th International Conference on Biobased Materials and Composites, Nantes, 29-31 March.Considering the over-exploitation of fossil resources and the release of greenhouse gas into the atmosphere, the development of a plant biorefinery is a major challenge for the next years in order to produce biomolecules, bioenergy and biomaterials. The conversion of lignocellulosic biomass coming from forest residuals, crop residues, and energy crops present a special interest as it is not actually competing with food applications. In this context the present work focuses on an agricultural by product, the corn stalk which is composed of two main anatomical parts: the pith, the inner part constituted of some vascular bundles dispersed in large parenchyma cells, and the rind, composed of closely spaced vascular bundles embedded in small-diameter parenchyma tissue. The alveolar structure observed in the pith is similar to the structure of expanded polystyrene and could explain the insulating properties observed in composites prepared from crop pith like sunflower and corn [1, 2]. One of the challenges to produce crop bio-based insulating boards at large scale is obtaining the pith by a mechanical and scalable method. Dry fractionation processes, which exhibit strong arguments of sustainability (no water consumption or drying of effluents), allowed dissociating plant structures at the relevant scale (0.5-4mm). In this work, firstly a dry fractionation diagram was developed at the kilogram scale in order to separate the rind from the pith of corn stem internode while preserving pith alveolated structure. Coarse grinding, based on shear as main mechanical stress, allowed dissociating both anatomical parts of the stem. They have been further separated based on their difference in apparent density using a gravimetric table. About 41% of the initial pith was recovered in fractions containing more than 92% of pith and with particles size higher than 1mm. Insulating composites were then produced with two fractions of corn pith and alginate as binder (Figure 1). The thermal conductivity is 0.046 W/mK (Fig1a), and 0.052 W/mK (Fig. 1b). This collaborative work highlights that dry fractionation preserves initial pith structure and the bio-based composited exhibit thermal conductivities in the range of conventional insulating materials
Development of a PET Prototype with Continuous LYSO Crystals and Monolithic SiPM Matrices
No full textThermo-physical properties of paraffin wax with iron oxide nanoparticles as phase change material for heat storage applications
No full textPhase change materials (PCMs) are growing in importance in many thermal applications as heat storage or to smooth the energy peak demand in many technological fields in industrial as well as in civil applications. Conductive nanoparticles can be added to phase change material to improve their thermo-physical properties. In this work, Iron oxide nanoparticles (IOx-NPs) were synthesized using a simple and green synthesis method, free of toxic and harmful solvents, using the extract of a plant as a reducer and stabilizer at two different temperatures of calcination 500°C and 750°C. The metallic oxide was used as an additive with 2% wt. compositions to paraffin wax to prepare a nanocomposite. The variation in thermal properties of paraffin wax in the composite was experimentally investigated. The biosynthesized IOx-NPs were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) and Thermal Gravimetric Analysis (TGA) techniques. The thermal properties of the synthesized nanocomposites were characterized by a thermal conductivity analyzer and differential scanning calorimetry (DSC). The FTIR spectra showed a bond at 535 cm-1, which confirms the Fe-O vibration. The XRD powder analysis revealed the formation of the cubic phase of Fe3O4 with an average particle size of 11 nm at 500°C and the presence of the phase α-Fe2O3 with Fe3O4 at 750°C. Scanning Electron Microscopy (SEM) showed that the obtained oxide was made up of particles of nanoscale size. Experimental measurements showed that the presence of nanoparticles can improve the latent heat capacity by a maximum of 16.16 % and the thermal conductivity of the nanocomposites by a maximum of 16.99%
Characterization of a PET detector head based on continuous LYSO crystals and monolithic, 64-pixel silicon photomultiplier matrices
No full textThe characterization of a PET detector head based on continuous LYSO crystals and silicon photomultiplier (SiPM) arrays as photodetectors has been carried out for its use in the development of a small animal PET prototype. The detector heads are composed of a continuous crystal and a SiPM matrix with 64 pixels in a common substrate, fabricated specifically for this project. Three crystals of 12 mm x 12 mm x 5 mm size with different types of painting have been tested: white, black and black on the sides but white on the back of the crystal. The best energy resolution, obtained with the white crystal, is 16% FWHM. The detector response is linear up to 1275 keV. Tests with different position determination algorithms have been carried out with the three crystals. The spatial resolution obtained with the center of gravity algorithm is around 0.9 mm FWHM for the three crystals. As expected, the use of this algorithm results in the displacement of the reconstructed position toward the center of the crystal, more pronounced in the case of the white crystal. A maximum likelihood algorithm has been tested that can reconstruct correctly the interaction position of the photons also in the case of the white crystal
Formulaciones de nuevos morteros y cementos especiales basadas en suproductos de magnesio
No full textAquesta tesi conté una recerca amb possibilitat de generar una patent, que afecta a "Magnesitas Navarras S.A"[spa] En la presente tesis doctoral se evalúa el potencial de algunos subproductos de magnesio empleados para la formulación de diferentes materiales de construcción y su utilización en diferentes soluciones constructivas. En este sentido, el uso de subproductos industriales para el desarrollo de materiales de construcción potencia criterios de sostenibilidad y beneficios medioambientales asociados a la reutilización de materiales secundarios y a la disminución de actividades extractivas de recursos naturales.
La memoria de la presente tesis doctoral se ha estructurado siguiendo el mismo eje conductor desarrollado en la parte experimental del trabajo. Así, ésta incluye una primera parte en la que se detalla el estado del arte referente a los materiales de construcción, así como las soluciones constructivas propuestas. Estas soluciones son, por un lado, el desarrollo de morteros destinados a la protección pasiva frente al fuego (PPF) y, por otro, la formulación de cementos químicos de fosfato (CBPC) de magnesio como material reparador de estructuras de hormigón.
Como primer punto del trabajo experimental se ha estudiado y caracterizado exhaustivamente los diferentes subproductos empleados, tanto físico-química como morfológicamente. Esta caracterización preliminar es de gran importancia en el desarrollo de la investigación, dado que, al tratarse de subproductos industriales, no se conocen de antemano las características y las propiedades que éstos presentan, siendo su conocimiento de vital importancia para la correcta consecución de los objetivos establecidos.
En el desarrollo experimental de la primera de las soluciones constructivas propuestas, se ha empleado dos subproductos de magnesio [Low-Grade Magnesium Hydroxide (LG-MH) y Low-Grade Magnesium Carbonate (LG-MC)] en la formulación de morteros PPF, utilizando en este caso el cemento Portland convencional como material aglomerante. Ambos subproductos industriales descomponen térmicamente mediante procesos endotérmicos que cubren un amplio rango de temperaturas, retardando así el tiempo necesario para alcanzar una determinada temperatura. En este caso, se han formulado morteros empleando como áridos distintos porcentajes de ambos subproductos, dando lugar a un material con buenas propiedades térmicas y mecánicas, factible de ser utilizado como un mortero PPF. Sin embargo, su utilización como mortero revoco puede verse limitada por la elevada densidad de los áridos utilizados. En este supuesto, puede mejorarse su aplicabilidad añadiendo a los morteros formulados con subproductos de magnesio un árido ligero, como la vermiculita, sin que ello perjudique al resto de propiedades evaluadas.
En la consecución de la segunda solución constructiva propuesta, se evalúa la viabilidad del uso como materia prima de otro subproducto de magnesio [Low-Grade Magnesium Oxide (LG-MgO)], en este caso para el desarrollo de cementos químicos de fosfato (CBPC) de magnesio. A tal efecto, se han determinado las propiedades mecánicas de distintas dosificaciones, así como el efecto de un aditivo retardante del fraguado, el ácido bórico (HB), descrito en la bibliografía como retardante de fraguado que permite mejorar la trabajabilidad de los CBPC. Este estudio se ha realizado empleando una herramienta estadística, el diseño de experimentos (DoE), con la finalidad de obtener modelos matemáticos que justifiquen las interacciones entre los distintos componentes de la mezcla y su efecto sobre las propiedades mecánicas y el tiempo de fraguado. Asimismo, el uso del DoE ha de permitir reducir el número de experimentos y establecer el mejor rango de dosificaciones en función de las características deseadas, dando lugar a una formulación adecuada para su utilización en las soluciones constructivas objeto de estudio. Destacar que el uso de LG-MgO en la formulación de CBPC introduce fases inertes no-reactivas contenidas en el propio subproducto, lo que implica que los CBPC desarrollados puedan considerarse como morteros.
A partir de los resultados obtenidos se ha seleccionado un pequeño grupo de formulaciones con porcentajes adecuados para evaluar su potencial empleo en el desarrollo de morteros reparadores de estructuras de hormigón. Con este propósito, se han realizado ensayos de adhesión sobre distintos sustratos (hormigón o terrazo) y se ha determinado algunas propiedades requeridas para su uso en la solución constructiva propuesta.
La presente tesis doctoral pretende confirmar la viabilidad tecnológica para los distintos campos de aplicación que se han postulado. Sin embargo, no es un objetivo de este estudio el desarrollar un producto final que pueda ser comercializado, sino demostrar su viabilidad gracias al know-how adquirido durante los años de esta investigación, y sentar así las bases para futuros estudios en el desarrollo de materiales de construcción empleando estos subproductos.[eng] The present thesis is focused in the assessment of some magnesium by-products and their potential reutilization for the formulation of different materials for several construction applications. Therefore, the use of industrial by-products for the development of construction materials highlights the sustainability criteria along with the environmental benefits associated with the reutilization of secondary materials whilst diminishing the extractive activities of natural resources.
This thesis has been structured following the same pattern for the experimental work. Thus, the first part details the state of the art in what construction materials concerns as well as some of the construction solutions suggested. These solutions are, on the one hand, included in the development of mortars for passive fire protection (PFP) and, on the other hand, in the formulation of chemical bonded phosphate ceramics (CBPC) as a repairing material for concrete structures.
The first part presents an exhaustive chemical, physical and morphological characterization of the by-products used. This preliminary characterization is of great importance in the development of the research because of the industrial origin of these by-products.
In the first part of the experimental section, the first of the solutions proposed used two types of magnesium by-products [Low-Grade Magnesium Hydroxide (LG-MH) and Low-Grade Magnesium Carbonate (LG-MC)] in the formulation of PFP mortars, using conventional Portland cement as a binder. Both industrial by-products thermally decompose through endothermic processes in a wide range of temperatures, delaying the time needed to achieve a selected temperature. In this case, the mortars were formulated by using different percentages of both by-products as aggregates, obtaining a material with good thermal and mechanical properties and therefore feasible to be used as a PFP mortar. However, its utilization as a sprayed mortar can be limited because of the high density of the aggregates used. In this sense, the practical applicability can be improved by adding a lightweight aggregate such as vermiculite, without diminishing the rest of the assessed properties.
Subsequently, in the second part of the experimental section, the viability of another magnesium by-product [Low-Grade Magnesium Oxide (LG-MgO)] is evaluated. In this case, for the development of chemical bonded phosphate ceramics (CBPC). The assessment was made by determining the mechanical properties of different dosages as well as by measuring the effect of a setting-time retarder additive, boric acid (HB), described in the literature as a good additive for this purpose while improving workability as well. This study has been realized by means of a statistical method, the design of experiments (DoE), with the purpose of obtain mathematical models that justify the interactions between different components in the mix and their effect in the mechanical properties and the setting-time. Moreover, the use of DoE enables the reduction in the number of experiments and establishes the best range of dosages as a function of the desired characteristics, giving an optimized formulation to be used in the construction solutions that are object of study. It has to be emphasize that the use of LG-MgO in the formulation of CBPC introduces inert phases that are contained in the by-product itself and that are non-reactive, which implies that the CBPC obtained could be considered as mortars.
From the results obtained, a small group of formulations with different percentages was selected to be studied with respect their potential as repairing mortars in concrete structures. Following this objective, adhesion tests were performed over different substrates (concrete or terrazzo) and some of the properties required for their use were determined.
The main objective of this thesis is to confirm the technological viability for the different fields of application postulated. However, it is not the main purpose to develop a final product able to be commercialized but to prove the viability by means of the know-how acquired during the years of this research and setting up the base for future studies in the development of construction materials using these by-products
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