Papers by Paula Lopez-Arce
Journal of Cultural Heritage, 2017
Boletin De La Sociedad Espanola De Ceramica Y Vidrio, Dec 1, 2003
El circón (ZrSiO 4) es un material que se utiliza habitualmente en la fabricación de refractarios... more El circón (ZrSiO 4) es un material que se utiliza habitualmente en la fabricación de refractarios, esmaltes para azulejos, pigmentos, etc. Este mineral tiene un alto contenido radiactivo debido a la presencia de emisores alfa naturales como U y Th. En este trabajo se ha determinado el contenido isotópico de estos radionucleidos (238 U, 235 U y 234 U, 228 Th, 230 Th y 232 Th) utilizando técnicas de separación radioquímicas y cuantificando la actividad mediante espectrometría alfa. Estos radioisótopos naturales producen una irradiación interna en el material cerámico que se manifiesta en sus propiedades luminiscentes lo que implica que pueda ser utilizado con fines dosimétricos. Se ha observado que la curva de termoluminiscencia (TL) del circón muestra una intensidad considerablemente mayor (más de un orden de magnitud) que la de otros silicatos medidos en idénticas condiciones. Los máximos que aparecen en la curva de TL se correlacionan con distintos puntos de inflexión que aparecen en la medida de análisis térmico diferencial (ATD), a 280, 360 y 445 o C, lo que indica que estos picos de TL aparecerán como consecuencia de: (1) procesos parciales de transiciones de fase locales y (2) fenómenos de autodifusión iónica y deshidroxilación que se producen durante el calentamiento al realizar la medida. Palabras clave: Circón, termoluminiscencia, contenido radiactivo, ATD Characterization of the thermoluminescence curve of zircon by radiactive content and differential thermal analysis Zircon (ZrSiO 4) is a mineral widely employed in the production of refractories, pigments, glazed tiles etc. The high radioactive content of this mineral stems from the presence of natural alpha emitters as U and Th. The radioactive activity of the 238 U, 235 U and 234 U, 228 Th, 230 Th and 232 Th radionuclides was measured by alpha spectrometry after isolation by radiochemical techniques. The alpha-emitters uranium and thorium irradiates internally the ceramic modifying the luminescence properties, this involves a potential use for dosimetric purposes. The thermoluminescence (TL) glow curve intensity of zircon is higher than the observed in other aluminosilicates measured under the same conditions. The TL maxima appearing at 280, 360 and 445 o C are fairly well correlated with the differential thermal analysis (DTA). It suggests that this TL peaks could be linked to: (1) partial processes of local phase transitions and (2) alkali self-diffusion dehydroxylation phenomena when the sample is heated during the analytical measurement routine.
Monitoring and Assessment of Atmospheric Moisture Imbalance: Elimination and Prevention of Condensation and Mould in Buildings
An innovative method known as Building Moisture Index (BMI) has been applied in hundreds of prope... more An innovative method known as Building Moisture Index (BMI) has been applied in hundreds of properties suffering of surface condensation and mould growth in order to quantify and rectify indoor atmospheric moisture imbalance. BMI system is a protocol, a method and a computer program that processes, assesses and reports environmental data in a fast, reliable and objective scientific-technical manner. An example is presented showing the causal factors diagnosed by the BMI code. The ventilation system was in this case improved, and moisture issues were automatically rectified, being this indicated by very high going down to low moisture imbalance scores, before and after installation, respectively. Following appropriate methods and protocols for environmental monitoring and assessment of moisture imbalance of indoor environments may support better retrofitting works to eliminate or avoid condensation damp and mould problems in residential buildings. Peer-review under the responsibility of the organizing committee of the ICMB21.
World Academy of Science, Engineering and Technology, International Journal of Civil, Environmental, Structural, Construction and Architectural Engineering, Jan 7, 2019
This study is focuses on the characterisation of the pastes and enamels constituents of the decor... more This study is focuses on the characterisation of the pastes and enamels constituents of the decorative ceramics, cladding ceramics and mosaic tiles, covering the façades and the central garden fountain of the Former Workers Hospital of Maudes at Madrid, Spain. The structural bricks of the inner fabric walls and those used at the courtyards are also studied. Both the original and restoration materials are analysed petrographically and mineralogically and the elemental composition of the enamel is determined. The major textural and compositional variations identified in the materials are mainly due to differences in the clay raw materials and additives used, as well as to the manufacturing processes, specially firing temperatures. In addition to comparing the results of the analyses conducted to the information obtained from the references consulted, the study provides unknown data on the raw materials and technologies involved in manufacturing the ceramic materials found in a heritag...
EVALUACIÓN DE TECNICAS DE LIMPIEZA Y DESALINIZACIÓN EN LA CATEDRAL DE SEGOVIA, ESPAÑA Mónica Álva... more EVALUACIÓN DE TECNICAS DE LIMPIEZA Y DESALINIZACIÓN EN LA CATEDRAL DE SEGOVIA, ESPAÑA Mónica Álvarez de Buergo (1); Carmen Vázquez-Calvo (2); Paula López-Arce (3); Rafael Fort (4) Doctora en Ciencias Geológicas. Instituto de Geociencias IGEO (Consejo Superior de Investigaciones Científicas – Universidad Complutense de Madrid, CSIC,UCM), Madrid, España, monica.alvarez@csic.es Licenciada en Ciencias Geológicas, Instituto de Geociencias (CSIC,UCM), Madrid, España, carmenvazquez@geo.ucm.es (3) Doctora en Ciencias Geológicas, Instituto de Geociencias (CSIC,UCM), Madrid, España, plopezar@ucm.es (4) Doctor en Geología Económica, Instituto de Geociencias (CSIC,UCM), Madrid, España, rafael.fort@csic.es
Stone materials used in the construction of the Spanish Fortress of Bizerte (Tunisia), show a hig... more Stone materials used in the construction of the Spanish Fortress of Bizerte (Tunisia), show a high degree of alteration. Samples of these rocks, calcarenites, were collected and treated with different consolidants. Then, they were subsequently subjected to salt spray test with ventilation, in order to test the effectiveness of the products under these conditions. The results obtained from the samples mass loss and macro and microscopic inspection made possible to compare the performances of the different consolidants. These studies allow to predict the behavior of these stony materials in the field and to decide the best application in the rocks present in monuments, optimizing solutions for conservation and restoration.
Programa Geomateriales (S2009/MAT-1629/GEOMATERIALES), Programa Consolider-Ingenio 2010 (CSD2007-... more Programa Geomateriales (S2009/MAT-1629/GEOMATERIALES), Programa Consolider-Ingenio 2010 (CSD2007-0058), JAE- CSIC y European Social Fund (FSE 2007-2013)
IOP Conference Series: Materials Science and Engineering, 2019
Increased occupancy rates, inappropriate ventilation and intermittent heating regimes in dwelling... more Increased occupancy rates, inappropriate ventilation and intermittent heating regimes in dwellings can result in excessive atmospheric moisture levels, potentially leading to mould growth and lower indoor air quality. Identifying the causes associated to mould growth and taking correct remedial actions can be essential in reducing the prevalence of this problem. In practice it is often complex, even for experts, to accurately identify some of these causes and this can lead to costly and unnecessary interventions. Towards development of a novel systematic diagnostic procedure an extensive monitoring exercise has been undertaken involving collection of environmental data from dwellings with and without mould issues. The data has been analysed, considering building characteristics and occupancy’s lifestyle features, with the objective to identify thresholds on measurable parameters that are indicative of mould growth risks. The proposed methodology links key parameters to identify fact...
Hydrothermal pyrite is an important source of thallium (Tl) but this rare element can be also det... more Hydrothermal pyrite is an important source of thallium (Tl) but this rare element can be also detected in the secondary iron goethite-lepidocrocite and jarosite ores, associated to hydrothermal kerogen, manganese oxides, accessorial potassium minerals and tiny Tl-bearing clusters shielded in quartz masses. We studied Tl-bearing samples collected from Fe-Mn ores hosted in dolostone rocks sited along ca. 15 km of fossil thermal springs following a geological fault in the Lodares surroundings. Samples were analyzed by environmental scanning electron microscopy and energy dispersive spectroscopy (ESEM-EDS), electron probe micro-analysis (EPMA), inductively coupled plasma-mass spectroscopy (ICP-MS), X-ray diffraction analysis (XRD), Tl LIII-edge X-ray absorption near-edge structure (XANES) spectroscopy, Micro-Raman and Fourier transform infrared spectroscopy (FTIR). We found epithermal pyrite, sphalerite, galena and baryte and secondary gypsum, jarosite, scorodite, anglesite, goethite, e...
Journal of Materials in Civil Engineering, 2017
The Spanish Fortress of Bizerte in Tunisia shows differential erosion patterns on the rock ashlar... more The Spanish Fortress of Bizerte in Tunisia shows differential erosion patterns on the rock ashlars used in the construction of its main façade (sixteenth century) exposed to marine aerosol action and several restoration works. In order to determine the origin of this erosion and the degree of stone decay, a combination of microdestructive and nondestructive techniques have been used on-site and in the laboratory. Moisture measurements, ultrasonic velocity propagation, and water absorption by a Karsten pipe test, together with polarized light and fluorescence optical microscopy, mercury intrusion porosimetry, and ion chromatography analyses, were carried out to perform petrophysical characterization of stone samples and determination of soluble salts. Results show that the differential stone weathering is caused by small variations in the petrographic characteristics of the construction's geomaterials, such as the type and degree of cementation, porous network configuration, and presence or absence of soluble salts. These variations are also detected by the portable nondestructive techniques, showing their analytical sensitivity to small petrophysical changes even in the same type of rock and their performance in predicting future degradations not currently visible on the surface of the rocks.
Construction and Building Materials, 2016
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Materials and Structures, 2016
Stone-mortar specimens manufactured with limestone and commercial stone-repair 11 hydraulic morta... more Stone-mortar specimens manufactured with limestone and commercial stone-repair 11 hydraulic mortars have been exposed to accelerated ageing tests, salt crystallisation 12 (mixture of sodium chloride, sodium sulphate, calcium sulphate and potassium nitrate) 13 and acid vapours exposure (sulphurous and nitric acid) besides, their corresponding 14 control specimens were exposed to deionized water imbibition cycles and water vapour, 15 respectively. Large amounts of soluble nitrates and minor amounts of sulphates 16 precipitate on the surface of both stone and mortar materials after the acid test. This 17 mainly affects the surface of the specimens rather than the stone-mortar interface. 18 Whereas parallel fissures to the interface show up due to salt mixture crystals 19 precipitation after the salt crystallisation test. 20 A remarkable yellowing of the stone takes place after both tests. The mortar with closest 21 properties to Euville limestone, with no phyllosilicates is the most resistant. It shows 22 good mechanical properties but bad hydric interactions with the stone that could prove 23 damaging in the long run. The mortar with the highest porosity and better hydric 24 behavior but poor mechanical interaction with the stone is highly affected by the ageing 25 tests, acting more as a sacrificial mortar rather than as a repair mortar. 26 27 Manuscript after referees corrections and English proofreading Click here to download Manuscript Lopez-Arce_ MAAS-D-15-01082_FINAL_AfterReferees_AllCorrected.docx Click here to view linked References
AIP Conference Proceedings, 2016
One hundred and sixty five years ago, Henry Clifton Sorby developed a revolutionary technique to ... more One hundred and sixty five years ago, Henry Clifton Sorby developed a revolutionary technique to prepare thin and polished sections of rocks and minerals to be observed by transmission and reflectance in the optical polarized light microscopes. Nowadays, Sorby's methods are still employed for near all inorganic materials with scarce modifications. The optical microscopy subject is essential for rocks analysis; it is an irreplaceable technique for specific complex samples, such as twinned-exsolved feldspars and it must be preserved in the geosciences curriculum. However, for many valuable and common specimens we observe a strong growing of non-destructive techniques coupled to the large chambers of modern microscopes including new chemical, molecular, luminescent, metrical, imaging and structural probes. Suitable explanations for the thin sections decreasing in research laboratories could be: (i) the undesirable cutting of the specimen; (ii) the contamination of surfaces by abrasives and glues; (iii) the etching with dangerous acids; (iv) the slow and painful works of cutting, grinding and polishing specimens; (v) the necessary protection of valuable specimens, (vi) the need for immediate analytical results.
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Papers by Paula Lopez-Arce