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The fabrication of low-electrical-percolation-threshold polymer composites aims to reduce the weight fraction of the conductive nanomaterial necessary to achieve a given level of electrical resistivity of the composite. The present work aimed at preparing composites based on multiwalled carbon nanotubes (MWCNTs) and magnetite particles in a polyurethane (PU) matrix to study the effect on the electrical resistance of electrodes produced under magnetic fields. Composites with 1 wt.% of MWCNT, 1 wt.% of magnetite and combinations of both were prepared and analysed. The hybrid composites combined MWCNTs and magnetite at the weight ratios of 1:1; 1:1/6; 1:1/12; and 1:1/24. The results showed that MWCNTs were responsible for the electrical conductivity of the composites since the composites with 1 wt.% magnetite were non-conductive. Combining magnetite particles with MWCNTs reduces the electrical resistance of the composite. SQUID analysis showed that MWCNTs simultaneously exhibit ferromagnetism and diamagnetism, ferromagnetism being dominant at lower magnetic fields and diamagnetism being dominant at higher fields. Conversely, magnetite particles present a ferromagnetic response much stronger than MWCNTs. Finally, optical microscopy (OM) and X-ray micro computed tomography (micro CT) identified the interaction between particles and their location inside the composite. In conclusion, the combination of magnetite and MWCNTs in a polymer composite allows for the control of the location of these particles using an external magnetic field, decreasing the electrical resistance of the electrodes produced. By adding 1 wt.% of magnetite to 1 wt.% of MWCNT (1:1), the electric resistance of the composites decreased from 9 × 104 to 5 × 103 Ω. This approach significantly improved the reproducibility of the electrode’s fabrication process, enabling the development of a triboelectric sensor using a polyurethane (PU) composite and silicone rubber (SR). Finally, the method’s bearing was demonstrated by developing an automated robotic soft grip with tendon-driven actuation controlled by the triboelectric sensor. The results indicate that magnetic patterning is a versatile and low-cost approach to manufacturing sensors for soft robotics.

A detailed archaeometric study of Phoenician ceramics found in an excavation inside the medieval walls of Sao Jorge's Castle in Lisbon is described here. Thirty ceramic sherds were studied, grouped into six categories, namely amphorae, containers for domestic use, red slip wares, grey wares, cooking wares and also some indigenous tradition handmade wares. Micro-Raman, X-Ray Fluorescence Emission, X-Ray Diffraction and ground state diffuse reflectance absorption measurements were correlated and used as our main analytical techniques to perform this study. At least three totally different local clay sources were used to produce the here studied pottery, one of alluvial origin using clays collected along the river banks, and another one using clays probably extracted in the oriental part of the Castle's hill. Cooking-ware was made with the use of raw materials with sandy detrital origin. Evidence was also found showing that part of the amphorae, common containers, and grey wares were made with the same raw materials as used in the Phoenician kilns of Almaraz, located in the left margin of the Tagus River, roughly facing Lisbon's Castle hill. The temperatures of the kilns used to fire the amphorae and common containers was in most cases higher than the one used for firing red slip and grey tableware. A detailed laboratorial study of the alluvial clays fired at different temperatures and collected in the Tagus River banks, allowed us, in most cases, to establish the origin of the sources used to produce the Phoenician pottery found in Lisbon.

No envelhecimento acelerado de rochas ornamentais em câmara saturada em SO2, as interações físico-químicas têm o objetivo de simular a exposição das mesmas às chuvas ácidas. As presenças de SO2, de H2O, somadas à incidência de radiação solar (externa) permitem a formação fotoquímica do ácido sulfúrico (H2SO4) e a correlação entre as digitalizações das superfícies dos corpos de prova, antes e após as exposições ao H2SO4, propicia a análise da evolução das alterações causadas. A estimativa do tempo gasto, em anos, para que as alterações descaracterizem totalmente a aparência estética da superfície das amostras é feita com a progressão aritmética do coeficiente de correlação linear de Pearson (r) que permite, quando igual a 0 (zero), afirmar a inexistência de correlação entre imagens de amostras submetidas ao ensaio e suas imagens originais ao natural. Os resultados apontam o Butterfly Gold como o mais susceptível à descaracterização estética superficial (3,08 anos), seguido do Butterfly Green (3,91 anos) e do Butterfly Beige (16,03 anos). Ressalta-se que a descaracterização não implica, necessariamente, em alteração ou comprometimento estrutural ou físico-mecânico da rocha. A concentração do gás na câmara (25 ppm) foi superelevada propositalmente para acelerar o processo de deterioração. É importante lembrar que a câmara simula as condições climáticas em fluxo praticamente contínuo necessitando o pesquisador, para as interpretações, considerar a concentração de SO2 na atmosfera, a duração das estações chuvosas, a incidência de chuvas ácidas e suas intensidades ao longo de um ano nos diferentes territórios. As previsões aqui realizadas não são impeditivos para aplicação destes materiais em ambientes externos nem tampouco internos, pois procedimentos usuais de limpeza podem ser perfeitamente aplicados para conservação dos mesmos.

Correctly describing the deterioration patterns is of great importance for the conservation of built cultural heritage. Also, their rapid in situ quantification is an essential requisite when studying exposed stone objects, to define satisfactory restoration actions and to avoid greater damage due to the application of incorrect treatments. The research described in this paper targets developing a methodology to compute the extent of different deterioration patterns on a granitic cultural heritage object using as a case study an overpass bridge called Puente Nuevo in Ourense (NW Spain). The applied methodology consisted of the combination of the geometric and radiometric information collected from a non-invasive and in situ mobile LiDAR system (MLS) and micro destructive analytical techniques. Laser scanning points were used as a base to create orthophotos, being their intensity values the input for an unsupervised classification method to determine the areas occupied for those different deterioration patterns. In parallel, as part of this multi-analytical approach different conventional analytical techniques (X ray diffraction, Fourier transform infrared spectroscopy and optical microscopy) were applied to chemically and mineralogically characterize those deterioration patterns, namely, gypsum black crust, calcite encrustations and biological colonization (mosses). LiDAR technology allowed to determine three different clusters considering the reflectance of those surfaces: uncoated granite, calcite encrustations and black crusts and biological colonization patinas in a combined cluster due to their close reflectance spectra. The computed extent and the location of those deterioration patterns will allow to identify the most suitable cleaning treatment saving money and time.

This work was funded by the Leverhulme Trust (RPG-2015-071). Dr. C. Cousins also wishes to acknowledge funding from the Royal Society of Edinburgh. This work was financed by FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 - Operacional Programme for Competitiveness and Internationalisation (POCI), and by Portuguese funds through FCT - Fundação para a Ciência e a Tecnologia in the framework of the project POCI-01-0145-FEDER-029932 (PTDC/FIS-AST/29932/2017). Exogenous organic molecules are delivered to the surface of Mars annually, yet their fate is largely unknown. Likewise, the survivability of putative organic biomarkers directly implicates current Mars surface exploration ambitions. Among these, amino acids are valuable target molecules due to their abiogenic and biological origins. We present the fundamental, but not previously considered, factors that affect the fate of amino acids embedded in Mars mineral analogues when exposed to ionising radiation. Using existing experimental datasets, we show that the attenuation coefficient at 200 nm for amino acids is an effective parameter for quantifying organic survivability, especially when mineral shielding is limited or absent. Conversely, the dielectric constant of a material is a potential key parameter regarding mineral shielding, as it accounts for iron content, and the physical properties of the material (pore size, surface area or water content). Finally, we combine Martian climatic parameters (surface temperature and atmospheric opacity) to show that the relative UV environment varies significantly on Mars as a function of latitude, providing a reference point for future Mars simulation studies. Postprint

In this study, low-carbon recycled cement (RC) was produced from thermally activated concrete and cement paste wastes and its incorporation in mortars, as cement replacement, was investigated. The calcination temperatures were defined based on thermogravimetric and X-ray diffraction analysis. Mortars were characterized in terms of their main fresh and mechanical properties (compressive and flexural strength, ultrasonic pulse velocity and dynamic modulus of elasticity). The influence of RC replacement ratio (20%, 50%, 75% and 100%), RC treatment temperature and RC fineness were analyzed. In all tested properties, RC from concrete waste showed significant lower efficiency than that from cement paste waste. The RC rehydration capacity was improved by increasing its fineness and pre-heating temperature. Mortars produced with 100% of 650 °C pre-heated RC were able to attain as high as 8.3 MPa of compressive strength at 28 days, corresponding to about 20% of that found in reference mortars without RC. In addition, mechanical properties were little affected by RC replacement ratios up to 20%. This study shows the efficient rehydration capacity of thermal activated RC and suggests its high potential for the construction industry.

The aim of this work was to assess the occupational dose received by an interventional radiologist (IR) during computed tomography fluoroscopy (CTF)-guided procedures; to identify the most exposed areas of the body including the hands and fingers; to suggest recommendations for individual monitoring; and to improve radiation safety of the practice. A total of 53 CTF-guided procedures were studied. Twelve whole-body dosimeters were worn by the IR in each procedure for the assessment of the personal dose equivalent, Hp(10), on the chest, waist, and back, both over and under the lead apron, as well as the personal dose equivalent, Hp(0.07), on both arms, knees, and feet. Special gloves with casings to fit extremity dosimeters were prepared to assess Hp(0.07) to the fingers. The measured chest dose values were higher than those on the waist and back; the dominant hand or the left side was the most exposed. In general, the ring, middle, and index fingers of the dominant hand were the most exposed (maximum in the 36–39 mSv range), while wrist dose was negligible compared to finger doses. Based on the results obtained the following recommendations are suggested: protective devices (lead aprons, thyroid shield, and goggles) should be worn; Hp(10) should be assessed at the chest level both above and below the lead apron; finger doses can be measured on the basis of each middle finger; the arm closer to the beam should be monitored; and finally, a wrist dosimeter will not provide useful information.

Cement pastes reinforced with various concentrations of functionalised and unfunctionalised carbon nanotubes (CNTs) with different aspect ratios were studied in terms of their dispersion and reinforcement efficiency. Mechanical strength was correlated with geometrical characteristics of CNTs, as well as the microstructure of reinforced pastes. Optimal CNTs of 0·05–0·1 wt% were found effective in increasing the flexural and compressive strength of reinforced pastes up to 36% and 27%, respectively. Efficiently dispersed CNTs were effective in bridging microcracks up to around 1 μm width. The CNTs did not significantly affect the phase composition of cement pastes but accelerated the hydration process. Based on a proposed equation, strength improvement was correlated with CNT aspect ratio and volume concentration. This equation establishes guidelines for maximised strength development based on geometrical and compositional parameters; it can be used for more rational design of CNT-reinforced cement materials, covering different compositions, as well as types and amounts of CNTs.

The fraction of organic matter present affects the fragmentation behavior of sialoliths; thus, pretherapeutic information on the degree of mineralization is relevant for a correct selection of lithotripsy procedures. This work proposes a methodology for in vivo characterization of salivary calculi in the pretherapeutic context. Sialoliths were characterized in detail by X-ray computed microtomography (μCT) in combination with atomic emission spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Correlative analysis of the same specimens was performed by in vivo and ex vivo helical computed tomography (HCT) and ex vivo μCT. The mineral matter in the sialoliths consisted essentially of apatite (89 vol%) and whitlockite (11 vol%) with average density of 1.8 g/cm3. In hydrated conditions, the mineral mass prevailed with 53 ± 13 wt%, whereas the organic matter, with a density of 1.2 g/cm3, occupied 65 ± 10% of the sialoliths’ volume. A quantitative relation between sialoliths mineral density and X-ray attenuation is proposed for both HCT and μCT.

Findings of Iron Age metallurgical activities related to tin metal and mining are very rare. In the present work, we present a detailed study of the Outeiro de Baltar hillfort, dated to the Late Iron Age/Early Roman period, located in a place where 20th century tin mining work took place. Elemental and microstructural analysis by portable, micro and wavelength dispersive X-ray fluorescence spectrometry (pXRF, micro-XRF and WDXRF) and scanning electron microscopy with energy dispersion spectrometer (SEM-EDS) showed that metallurgical debris found at the archaeological site is related to tin smelting and binary and ternary bronze productions. Analysis of the artefacts of diverse typologies found at the site showed that a variety of metals and alloys were in circulation and use. Samples of tin ores (cassiterite) from the region were analyzed for comparison with an archaeological tin slag from the site. The analytical results point to the production of tin metal using local cassiterite and the production of bronze by directly adding cassiterite into a smelting process. Furthermore, data of remote sensing (airborne Light Detection and Ranging (LiDAR) and historical aerial imagery) and Geographical Information System (GIS) mapping were combined with archival mining documentation and maps to retrieve a landscape context for the site. The study showed that the place of the Outeiro de Baltar hillfort (NW Iberia) was mined periodically over time. publishersversion published

The use of vegetable oils to produce biodiesel raises several sustainability issues, namely the fuel/food conflict. The high cost of vegetable oils and an expensive homogeneous base catalyzed process encourages the search for alternative raw materials and more efficient production processes. Biodiesel from beef tallow, a non-edible fat, was produced by methanolysis over calcium based heterogeneous catalyst. The catalyst was prepared by calcination of scallop shells at 800 ​°C. To overcome the undesired effect of the tallow acidity (3.9 mgKOH/gfat), mixtures of tallow and soybean oil (SBO) (0.6 mgKOH/gfat) were processed and alcohol co-solvents (isopropanol, 1-propanol, and isobutanol) and biodiesel itself, as a solvent, were used to improve the miscibility of the reaction mixture. Processing of neat tallow promotes an important decay of the catalytic activity due to the partial neutralization of the basic catalyst. Co-processing mixtures of tallow/SBO allowed minimizing the acidity effect. Alcohol co-solvents harmed the biodiesel yield due to competitive adsorption of alcohols with methanol on catalyst active sites but protected the catalyst against adsorption of the reaction mixture species. Biodiesel used as a solvent had an almost null effect on the esterification reaction yield, thus showing the absence of mass transfer limitation. Co-processing low-grade fat with vegetable oil seems to be a feasible strategy to process low-grade fats using basic heterogeneous catalysts, thus contributing to improving the sustainability of biodiesel production.

One of the aims of Goal 11 of the UN’s 2030 Agenda for Sustainable Development is to make human settlements sustainable. Some effort should therefore focus on developing maintenance strategies for buildings. Polished granite cladding tiles are very popular for use as flooring material in private and public buildings. These tiles are often treated by mechanical cleaning with detergents and scrubbers, and anionic detergents without chelating agents are usually used to prevent damaging the material. In this study, the anionic detergent Teepol® was applied to granite tiles in order to determine the effect of the treatment on the surface properties of this stone, i.e. appearance, colour, gloss, roughness and hydrophobicity. The results obtained were explained by scanning electron microscopy observations, which enabled characterisation of the microtexture of the surfaces, chemical contamination and any damage to the different granite-forming minerals. The results were compared with those obtained for tiles cleaned by the same mechanical procedure but with tap water in place of detergent and for tiles treated by immersion in water without any mechanical action. In summary, the properties evaluated were affected by the extraction of the typical oxyhydroxylated iron forms that fill cracks in the granite and by the formation of new cracks due to the mechanical action. Moreover, colour changes and the chemical contamination (C-rich deposits with Na, S, Cl, Ca and Mg) hindered the effectiveness of the cleaning procedure.

The on-board identification of ore minerals during a cruise is often postponed until long after the cruise is over. During the M127 cruise, 21 cores with deep-seafloor sediments were recovered in the Trans-Atlantic Geotraverse (TAG) field along the Mid Atlantic Ridge (MAR). Sediments were analyzed on-board for physicochemical properties such as lightness (L*), pH and Eh. Selected samples were studied for mineral composition by X-ray powder diffraction (XRD). Based on XRD data, sediment samples were separated into high-, low- and non-carbonated. Removal of carbonates is a common technique in mineralogical studies in which HCl is used as the extraction agent. In the present study, sequential extraction was performed with sodium acetate buffer (pH 5.0) to remove carbonates. The ratio between the highest calcite XRD reflection in the original samples (Iorig) vs its XRD-reflection in samples after their treatment with the buffer (Itreat) was used as a quantitative parameter of calcite removal, as well as to identify minor minerals in carbonated samples (when Iorig/Itreat &gt, 24). It was found that the lightness parameter (L*) showed a positive correlation with calcite XRD reflection in selected TAG samples, and this could be applied to the preliminary on-board determination of extraction steps with acetate buffer (pH 5.0) in carbonated sediment samples. The most abundant minerals detected in carbonated samples were quartz and Al- and Fe-rich clays. Other silicates were also detected (e.g., calcic plagioclase, montmorillonite, nontronite). In non-carbonated samples, Fe oxides and hydroxides (goethite and hematite, respectively) were detected. Pyrite was the dominant hydrothermal mineral and Cu sulfides (chalcopyrite, covellite) and hydrothermal Mn oxides (birnessite and todorokite) were mineral phases identified in few samples, whereas paratacamite was detected in the top 20 cm of the core. The present study demonstrates that portable XRD analysis makes it possible to characterize mineralogy at cored sites, in particular in both low- and high-carbonated samples, before the end of most cruises, thus enabling the quick modification of exploration strategies in light of new information as it becomes available in near-real time.

The archaeological site of Almaraz is located in the old part of the city of Almada, in the south shore of Tagus River, region of Lisbon. The excavated findings and the radiocarbon dating of the contexts where these were found show an occupation that can in fact be dated from the 8th to the 7th c. BCE period, thus a very early stage of the Phoenician occupation in the Iberian Peninsula. Numerous amphorae sherds were found at Almaraz. A spectroscopic characterization of those ceramics was made and is presented here, to help us understand if they were produced locally, in Lisbon workshops, or imported. Sixteen sherds representative of the thousands found at Almaraz were studied with the use of non-invasive spectroscopies, namely by crossing information from micro-Raman and X-ray fluorescence emission data. X-ray diffraction experiments were also performed. In spite of the fact that no ceramic kilns were found at Almaraz until now, the results point to two major groups of amphorae of local origin: one which used clays of Miocene origin, found on the southern shores of the Tagus River, very close to the Almaraz site, at Palenca (with quartz, anorthite, diopside and hematite). Another group, remarkably different, made use of clays of Pliocene origin also from the Tagus Estuary, the Fontainhas clay source (where quartz, anorthite, muscovite and hematite were found).

22 páginas.-- 6 figuras.-- 115 referencias.-- Additional Supporting Information may be found in the online version of this article: http://dx.doi.org/10.1111/sed.12431, Subsurface granitic environments are scarce and poorly investigated. A multi‐disciplinary approach was used to characterize the abundant moonmilk deposits and associated microbial communities coating the granite walls of the 16th Century Paranhos spring water tunnel in Porto city (north‐west Portugal). It is possible that this study is the first record of moonmilk in an urban subsurface granitic environment. The morphology and texture, mineralogical composition, stable isotope composition and microbial diversity of moonmilk deposits have been studied to infer the processes of moonmilk formation. These whitish secondary mineral deposits are composed of very fine needle‐fibre calcite crystals with different morphologies and density. Calcified filaments of fungal hyphae or bacteria were distinguished by field emission scanning electron microscopy. Stable isotope analysis revealed a meteoric origin of the needle‐fibre calcite, with an important contribution of atmospheric CO2, soil respiration and urn:x-wiley:00370746:media:sed12431:sed12431-math-0001 from weathering of Ca‐bearing minerals. The DNA‐based analyses revealed the presence of micro‐organisms related to urban contamination, including Actinobacteria, mainly represented by Pseudonocardia hispaniensis, Thaumarchaeota and Ascomycota, dominated by Cladosporium. This microbial composition is consistent with groundwater pollution and contamination sources of the overlying urban area, including garages, petrol stations and wastewater pipeline leakage, showing that the Paranhos tunnel is greatly perturbed by anthropogenic activities. Whether the identified micro‐organisms are involved in the formation of the needle‐fibre calcite or not is difficult to demonstrate, but this study evidenced both abiotic and biogenic genesis for the calcite moonmilk in this subsurface granitic environment., The authors acknowledge the Spanish Ministry of Economy, Industry and Competitiveness (MINEICO, project CGL2011-2569) and the Portuguese Foundation for Science and Technology, FCT (UID/GEO/04035/2013, UID/ECI/04028/2013, PEst-OE/CTE/UI0098/2011) and the LABCARGA| ISEP re-equipment program (IPP-ISEP|PAD’2007/ 08) for financial support. AZM thanks MINEICO for the ‘Juan de la Cierva – Incorporación’ postdoctoral contract (IJCI-2014-20443). PMMS thanks the Spanish Ministry of Science and Innovation for his contract associated with the ‘Research Programme in Technologies for the Assessment and Conservation of Cultural Heritage’ (TCP CSD2007-0005

A favourable electronic structure, together with a high abundance of pyrite (FeS2) in the Earth's crust, make this sulfide a promising material for thermoelectric applications. However, the experimental work published to date underlines a challenging scenario, with FeS2 presenting systematically small power factors. Knowing that sulfur vacancies are a key aspect for controlling the electronic transport properties of FeS2, this work focuses on the preparation of pyrite by hot-pressing and entails a careful characterization of its microstructure, chemical composition, thermal stability, and electrical transport properties. Dense pellets (>90% of the theoretical density) were obtained, consisting mostly of pyrite with trace amounts of Fe7S8. Different hot-pressing conditions led to similar chemical compositions, with no significant lattice distortions. Pyrite proved to be thermally stable up to 400 °C under an inert atmosphere. Analysis of the electronic band structure and density of states by density functional theory implies a p-type semiconductivity. However, measurements of Seebeck coefficient indicated n-type semiconductivity for pyrite produced by this experimental procedure. The highest power factor measured in this work, 0.23 μW K−2 m−1, is still far from what can be considered a promising value for thermoelectric materials, but different ways of improving it are discussed.

São estudadas as rochas ornamentais Butterfly Beige, Butterfly Gold e Butterfly Green correspondentes a quartzo sienitos com hiperstênio que são exploradas em Barra de São Francisco-Espírito Santo, Brasil. O objetivo é analisar os efeitos estéticos, bem como quantificá-los, depois de submetidas à exposição de temperaturas elevadas a partir de análises comparativas das imagens, das cores e das respectivas características petrográficas. Os valores para os coeficientes de correlação (r) entre as rochas, já nos primeiros 200ºC, mostram descaracterizações moderadas, sendo as rochas bastante afetadas pela temperatura. As alterações causadas pela ciclagem térmica somada à umidade aceleram o processo de oxidação do Fe. Além disso, por histerese, a ciclagem implica a geração de microfissuras e o alargamento dos planos de clivagem dos minerais, bem como ofusca os contatos entre eles, facilitando a percolação de fluidos (água) e aumentando o grau de oxidação do Fe ao mesmo tempo em que facilita a disseminação do Fe(OH)2. Frente aos resultados obtidos, sugere-se que as rochas estudadas (principalmente a variedade Green) sejam utilizadas em revestimentos de ambientes internos e que fontes de calor, como o sol, em revestimentos externos, podem acelerar o processo de modificação das cores em função da presença de minerais ferro-magnesianos e, principalmente, do Fe (OH)2 passíveis de oxidação

The recovery of lithium from hard rock minerals has received increased attention given the high demand for this element. Therefore, this study optimized an innovative process, which does not require a high-temperature calcination step, for lithium extraction from lepidolite. Mechanical activation and acid digestion were suggested as crucial process parameters, and experimental design and response-surface methodology were applied to model and optimize the proposed lithium extraction process. The promoting effect of amorphization and the formation of lithium sulfate hydrate on lithium extraction yield were assessed. Several factor combinations led to extraction yields that exceeded 90%, indicating that the proposed process is an effective approach for lithium recovery. info:eu-repo/semantics/publishedVersion

Separation is a fundamental step for concrete recycling, enabling not only the achievement of reliable and cleaner recycled aggregates but also the better re-use of the remaining concrete constituents. Recently, a new hydraulic binder produced from the hydrated cement paste contained in waste concrete, which is associated with lower processing temperatures and carbon dioxide emissions, has gained momentum in the history of concrete recycling. However, a decisive turning point for its application lies in the successful individualisation of the cement paste and aggregate initially contained in concrete debris. This paper describes a new patented method involving a mechanical comminution stage and a high-intensity magnetic separation process to obtain the cementitious fraction in concrete and retrieve cleaner fine aggregate. The efficiency of the proposed method was assessed through image analysis, thermogravimetry, X-ray diffraction and acid attack. In addition, cement pastes produced with the obtained recycled cement after thermal activation were characterised in terms of mechanical strength. Findings suggest that the proposed method effectively separated the main concrete constituents, especially when the waste material was reduced to the size range 150–500 μm. It was possible to obtain a recycled binder at the current laboratory scale with up to about 80% cement content by weight (nearly 90% in volume). Furthermore, a cleaner recycled fine aggregate, with minimal cement paste contamination, as low as less than 3 wt%, was also obtained. The mechanical strength of pastes with recycled cement retrieved from waste concrete was about 70% of that of reference pastes of equal water/binder produced with recycled cement from non-contaminated waste cement pastes.

Lithotripsy methods show relatively low efficiency in the fragmentation of sialoliths compared with the success rates achieved in the destruction of renal calculi. However, the information available on the mechanical behavior of sialoliths is limited and their apparently tougher response is not fully understood. This work evaluates the hardness and Young’s modulus of sialoliths at different scales and analyzes specific damage patterns induced in these calcified structures by ultrasonic vibrations, pneumoballistic impacts, shock waves, and laser ablation. A clear correlation between local mechanical properties and ultrastructure/chemistry has been established: sialoliths are composite materials consisting of hard and soft components of mineralized and organic nature, respectively. Ultrasonic and pneumoballistic reverberations damage preferentially highly mineralized regions, leaving relatively unaffected the surrounding organic matter. In contrast, shock waves leach the organic component and lead to erosion of the overall structure. Laser ablation destroys homogeneously the irradiated zones regardless of the mineralized/organic nature of the underlying ultrastructure; however, damage is less extensive than with mechanical methods. Overall, the present results show that composition and internal structure are key features behind sialoliths’ comminution behavior and that the organic matter contributes to reduce the therapeutic efficiency of lithotripsy methods.

Black crusts on different substrates (carbonate and silicate stones, cement-based mortar and carbonate detrital deposits) in urban environments were characterized microscopically by analysing their morphologies and compositions. The objective of this article is to study the interaction between the substrate and the crust and the influence of the environmental conditions on the crust development. On the one hand, the internal structure and morphology of each sample were evaluated with stereo and scanning electron microscopies. On the other hand, the black crust composition was accessed by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy in backscattered electron mode combined with energy dispersive x-ray spectroscopy. The results of these analytical techniques provided interesting information about the composition and the mineralogical phases present in the collected black crusts. In most of the cases, gypsum was detected as the main component exhibiting different habits. Calcite was also detected in all the evaluated gypsum black crusts; its presence was attributed to different origins. The substrate-crust interaction was also evaluated, contributing to distinguish different crust development processes in relation to the substrate. In carbonate substrates (limestones, mortar and carbonate detrital deposits), it was detected a continuous diffuse boundary related to the replacement of Ca-carbonate by Ca-sulphate, while this boundary was significantly more defined for the granitic stone. This study shows that the substrate, the presence of different construction materials, (e.g. mortars), the motor exhaust particulate substances and the concentrations of atmospheric pollutants, the marine influence as well as biological or other anthropogenic compounds are decisive factors in the development of the black crust. Some ideas about the establishment of conservation strategies are also shown.

The consumption of edible pine seeds of stone pine by the invasive Leptoglossus occidentalis represents a major concern for producers in Mediterranean countries but, to date, little knowledge is available about its feeding process on these seeds. In the present study, we tested whether L. occidentalis is capable of feeding upon mature pine seeds and also estimated the impact that they may induce. Sound pine seeds were offered to bugs under laboratory conditions. Seed content was analyzed via a multitechnique approach using a stereomicroscope, X-rays and microcomputed tomography, which was expected to better characterize the damage caused by this bug. Adults of L. occidentalis were capable of feeding on mature seeds by piercing the hard and thick coat. However, the consumption was low and demonstrated a slow start, presumably as a result of the time and effort taken to drill a feeding hole. A collaborative feeding process was suggested because all bugs in the same box appeared to have fed through the same hole in most cases. Consumption was estimated to be approximately one-fifth of a seed kernel per bug per month. Consumed kernels appeared skunked and wrinkled.

Mechanical activation in order to improve lithium recovery from a lepidolite ore concentrate was investigated. The concentrate was mechanically activated using different milling times and the effect on the resulting products was evaluated by X-ray powder diffraction, FTIR spectroscopy, TG-DTG analysis, SEM and particle size analysis by laser diffraction. The mechanical activation leads to lepidolite amorphization and concomitant improvement of the reactivity by sulfuric acid digestion and water leaching. About 85% of Li recovery was achieved when the concentrate was activated for 15 min and afterwards digested at 165 °C, during 4 h, using an acid/concentrate ratio of 650 g/kg. Li recoveries above 70% were reached even using digestion temperatures lower than 100 °C. However, to increase recovery, temperatures over 140 °C are more suitable. Results obtained showed that is possible to apply a low temperature technology for recovering Li from hard rock minerals, using mechanical activation.

Calcification, or mineralisation, can occur as part of a natural process, or by pathological processes. The purpose of this work is to examine an unidentified semi-spherical and perforate hollow mass, found near the pelvis of an adult female, dated 12th–13th century AD, exhumed of the Church of Santo Domingo de Silos (Pradena del Ricon, Madrid, Spain). The mass was examined by SEM and Energy Dispersive X-Ray Spectroscopy. These procedures revealed a heterogeneous inner surface with both smooth and irregular areas. A larger spherical and several smaller crescent-shaped perforations were noticed. X-ray microanalysis revealed the presence of the elements C, K, P, Ca, Al, Si, Fe, and Mg. The co-localisation of Ca and P suggests that they may be combined in a mineral matrix, likely formed in vivo. Other minerals probably came from the soil, although Fe could be related to the presence of blood. The macroscopic and microscopic appearances, chemical composition, and location of the calcified mass point to a possible hydatid cyst from Echinococcus granulosus, common in agricultural populations. This study used a suite of analytical techniques that are useful in the diagnosis of unknown calcified masses and can, therefore, be recommended for use in future analytical work.

15 páginas.- 5 figuras.- 85 referencias.- The following are available online at http://www.mdpi.com/2079-6412/10/11/1134/s1 .- This article belongs to the Special Issue Biofilms on Cultural Heritage, The Galapagos Islands (Ecuador) have a unique ecosystem on Earth due to their outstanding biodiversity and geological features. This also extends to their subterranean heritage, such as volcanic caves, with plenty of secondary mineral deposits, including coralloid-type speleothems and moonmilk deposits. In this study, the bacterial communities associated with speleothems from two lava tubes of Santa Cruz Island were investigated. Field emission scanning electron microscopy (FESEM) was carried out for the morphological characterization and detection of microbial features associated with moonmilk and coralloid speleothems from Bellavista and Royal Palm Caves. Microbial cells, especially filamentous bacteria in close association with extracellular polymeric substances (EPS), were abundant in both types of speleothems. Furthermore, reticulated filaments and Actinobacteria-like cells were observed by FESEM. The analysis of 16S rDNA revealed the presence of different bacterial phylotypes, many of them associated with the carbon, nitrogen, iron and sulfur cycles, and some others with pollutants. This study gives insights into subsurface microbial diversity of the Galapagos Islands and further shows the interest of the conservation of these subterranean geoheritage sites used as show caves, This research was funded by the Ecuadorian Ministry of Environment (Project PC-65-14 National Park Galapagos), by the Spanish project MINECO CGL2016-75590-P with European Regional Development Fund and the Portuguese Foundation for Science and Technology (Fundação para a Ciência e a Tecnologia-FCT) under the project UID/Multi/04449/2019 for HERCULES/UE. AMGS was supported by a FPU fellowship of the Spanish Ministry of Education, Culture and Sport (AP2010-2052). AZM was supported by a Marie Curie Intra-European Fellowship of the European Commission’s 7th Framework Programme (PIEF-GA-2012-328689-DECAVE) and a CEECIND/01147/2017 contract from FCT. MLC was supported by a CEECIND/00349/2017 contract from FCT. FG was financially supported by the “HIPATIA” research program of the University of Almeria.

11 páginas.- 7 figuras.- 1 tabla.- 73 referencias.- Supplementary data to this article can be found online a https://doi.org/10.1016/j.scitotenv.2019.134321, Siliceous speleothems frequently reported in volcanic caves have been traditionally interpreted as resulting from basalt weathering combined with the activity of microbial communities. A characteristic feature in lava tubes from Hawaii, Azores and Canary Islands is the occurrence of black jelly-like speleothems. Here we describe the formation process of siliceous black speleothems found in a lava tube from La Palma, Canary Islands, Spain, based on mineralogy, microscopy, light stable isotopes, analytical pyrolysis, NMR spectroscopy and chemometric analyses. The data indicate that the black speleothems are composed of a hydrated gel matrix of amorphous aluminum silicate materials containing charred vegetation and thermally degraded resins from pines or triterpenoids from Erica arborea, characteristic of the overlying laurel forest. This is the first observation of a connection between fire and speleothem chemistry from volcanic caves. We conclude that wildfires and organic matter from the surface area overlying caves may play an important role in the formation of speleothems found in La Palma and demonstrate that siliceous speleothems are potential archives for past fires., A.Z. Miller acknowledges the support from the Marie Curie Intra-European Fellowship of the European Commission seventh Framework Fig. 6. Contour van Krevelen density plots displaying cumulative abundances of pyrolysis compounds identified in Table S2 for: A) Erica arboreabiomass, B) Andosol topsoil, C) Black jelly-like speleothem 1 (BS1), and D) Black jelly-like speleothem 2 (BS2).9A.Z. Miller et al. / Science of the Total Environment 698 (2020) 134321 Programme (grant PIEF-GA-2012-328689) and the CEECIND/01147/2017 contract funded by Fundação para a Ciência e a Tecnologia (Portugal). The authors acknowledge the Spanish Ministry of Economy and Competitiveness (project CGL2013-41674-P) and ERDF funds forfi-nancial support. The authors are grateful to the speleologist OctavioFernández (GE Tebexcorade–La Palma) for the assistance during thefield trip and photographic documentation in the lava tubes from LaPalma Island

Calcium diglyceroxide (CaD) was used as the catalyst for biodiesel production through oil methanolysis. It was evaluated its catalytic behavior, its air expo- sure tolerance, and the Ca leaching. CaD catalyst was synthesized from food waste scallop shell derived CaO (obtained by calcination at 900 °C) by contacting with a mixture of equal volumes of glycerin and methanol at 65 °C for 2 h. The CaO obtained by calcination of scallop shell was used as reference catalyst. In standard reaction conditions (2.5 h, methanol reflux temperature, 5 wt% (oil basis) catalyst loading, and methanol:oil = 12:1 moral ratio), CaD presented lower catalytic activity than CaO (FAME yield of 92% against 99%, respectively). 24 h repined CaD presented improved catalytic behavior probably due to the formation of surface Ca −OH groups, achieving 96% of FAME yield. Thermogravimetry (TG) data showed that inorganic residue was larger for biodiesel than for glycerin, being CaD catalyst more soluble than CaO. Data showed that CaD is unstable under reaction conditions, suffering leaching, but the absence of Matter Organic Non-Glycerol (MONG) in the glycerin phase allows to neglect the homogeneous contribution of the leached catalyst. CaD formation during reaction contributes to FAME contamination with Ca and promotes catalyst deactivation thus being an undesired occurrence.

Biocementation is being used to seal cracks in stone and concrete for retrofitting and consolidation works, as alternative to conventional solutions such as using polymeric mortar. As when such traditional techniques are used, joint thickness and roughness play an important role on sealing efficiency and this must be investigated when using biocement. The efficiency of biocementation to seal joints in stone samples considering simultaneously their width and roughness is discussed in this paper. Joints with 0.4, 0.7 and 1 mm width, having smooth and rough surfaces, were artificially created on basalt stone disks. The joints were treated by biocementation until become sealed, i.e., until fluid stop flowing through the joint. Adhesion achieved with the treatment was evaluated by tensile strength measurements in Brazilian splitting tests, in which the samples were split by the sealed joint. The joint surfaces separated after the splitting test were analysed by digital analysis of photographs and stereomicroscope images to check the presence and homogeneity of the precipitated biocement. The tensile strength was larger for the artificial joints with larger width and rough surfaces (maximum values found are 3.94 and 5.67 MPa for the smooth and rough surfaces, respectively). The values found were half the values measured for the intact rock (8 MPa), but still in the order of magnitude of Mega Pascal, therefore indicating strong adhesion between the stone and biocement. Biocementation treatment therefore appears to be adequate for sealing stone joints with different widths within the range investigated and variable roughness.

The present study aims at evaluating the impact of anobiid damage on pine timber elements. Anobiid attack produces a diffuse damage of the elements with a set of tunnels in random directions and sizes, thus confusing quantification. Therefore, a method was developed based on X-ray micro-computed tomography (μ-XCT) to obtain, for naturally infested timber samples, an empirical correlation between lost material percentage (consumed by beetles) and timber apparent density (original, before degradation—OTD and residual, after degradation—RTD). The quantified density loss can then be used in further assessment of the structure. The results of the tests performed showed high correlation between original apparent density and lost material percentage (r2 = 0.60) and between residual apparent density and lost material percentage (r2 = 0.83), which confirms μ-XCT as a valuable tool to the required quantification. The loss of density results can be further applied on the definition of an assessment method for the evaluation of the residual strength of anobiids infested timber, thus contributing to reducing unnecessary replacement. The optimized procedure of the μ-XCT study for infested Maritime pine (Pinus pinaster) is presented and discussed in this article., The authors acknowledge the support given by Portuguese Foundation for Science and Technology (FCT) within research projects: PTDC/EPH-PAT/4684/2014 (DB-HERITAGE), PTDC/ECM-EST/1072/2014 (Pro-Timber), Pest-OE/CTE/UI4028/2011 (CERENA) and UIDB/ 04625/2020 (CERIS).

Considerable amounts of municipal solid waste incinerator bottom ashes are produced yearly without an adequate outlet. Given the established reactivity of the ash when subjected to an alkali medium, there is considerable scope to valorize it within the Construction industry in an alkali-activated material, thereby reducing the significant environmental pressure of the cement industry. This study assesses the optimization of alkali-activated mortars, using milled municipal solid waste incinerator bottom ash as a precursor, from mechanical and durability behaviour perspectives, many properties of which have never been analysed. The alkaline solution is comprised of either NaOH or Na2SiO3 (Na2O/precursor ratio varying between 9.1% and 24.2% and SiO2/Na2O ratios of 0 or 1.0); fly ash from a coal-fired power plant was also used as control precursor. X-ray fluorescence and powder X-ray diffraction analyses of cement, fly ash, bottom ash and of the resulting pastes were carried out. All specimens were evaluated in terms of their mechanical and durability-related performance (i.e. flexural and compressive strength, carbonation, water absorption by capillary action, and shrinkage). Considerable generation of H2 gas was observed during production, resulting from the reaction between the bottom ashes’ metallic aluminium fraction and the NaOH solution, leading to significant expansion and an overall increase in porosity and thus a strong decline in performance. Alkali-activated bottom ash specimens presented fast carbonation, resulting in a considerable strength increase. Despite the low performance of most of these mixes, the strength enhancement of specimens subjected to some conditions infers that there is significant scope for further mix design optimization (e.g. aluminium reduction, mixing time, Na2O/precursor and SiO2/Na2O ratios) that can lead to the manufacture of fit-for-industry construction materials.

Milled municipal solid waste incinerator bottom ash was used as a precursor in the production of alkali-activated mortars with recycled concrete aggregates as a sand substitute. Fly ash was used as control precursor and sodium hydroxide as an alkaline activator. Different thermal curing regimens were used: 24 h in ambient conditions; 24 h/70 °C; 48 h/70 °C; and 24 h/90 °C. Mechanical and durability-related performances were evaluated (i.e. flexural and compressive strength, modulus of elasticity, ultrasonic pulse velocity, carbonation, capillary water absorption, and shrinkage). The reaction between metallic aluminium from municipal solid waste incinerator bottom ash and OH− ions produced hydrogen gas, causing expansion, porosity increase and thus decline in performance. Low stability in high relative humidity settings due to leaching of highly soluble compounds was also observed. A further decline in performance was observed in mixes containing recycled aggregates. Alkali activated municipal solid waste incinerator bottom ash presented fast carbonation but also a considerable strength enhancement.

São Domingos sulfide mine was shut down more than 50 years ago leaving behind eroded and depositional surfaces due to acid mine drainage (AMD). The aim of this study was to assess six selected sites subjected to AMD, considered phytotoxic regions characterized by vegetation scarcity. Two main criteria, nature and composition of soluble fractions and total chemistry of surficial products related to jarosites presence, enabled to set up an overall dichotomy between superficial proximal/discharge and distal/sedimentation areas. Wet and dry sieving results comparison revealed that samples have a predominant sandy texture and lithic (phyllite, quartzite and volcanic country rocks) composition. Quartz, and subordinate feldspar enrichment is also detected in the coarse silt fraction. The results also suggest that the materials under study, when subjected to the local torrential hydrologic regime, have a high mechanical vulnerability, facilitating erosion and mud transport, both critical for vegetation support, and triggering contamination transfer and dispersion. The vicinity and ground-level surfaces of discharging areas are enriched in the jarosite group minerals whereas the sedimentation ones present hypersaline aluminous tendency. The formation of jarosite is considered as an efficient positive environmental contribution to metals and metalloids sequestration/immobilization. The remediation/revegetation solutions to be adopted in each location must have into consideration these differentiating aspects.

The lithium extraction from a lepidolite concentrate using roasting, followed by water leaching, was studied. Several alternative additives were initially tested. The use of sodium and calcium sulfates as additives was evaluated in more detail. The influence of some process variables, namely the roasting time, roasting temperature and the additive/concentrate mass ratio, was studied applying a design of experiments. The lithium extraction was modelled and the fitted and validated model was used to optimize the process response. The increase in the additive/concentrate mass ratio, roasting time and temperature seems to result in solid state reactions and transformations that lead to phase, morphological and particle size distribution modifications, which were assessed by XRPD, SEM, and particle size analyses. In this process, lithium sodium sulfate formation constitutes a crucial step enabling the Li water leaching. High lithium extractions were estimated for several combinations of factors. At 850...

Stone coatings, biological colonization, efflorescence and detachments are frequent on granitic surfaces of our cultural heritage infrastructure. In order to find the different origins for each deterioration form, this paper studies and compares several coatings, efflorescence and flakes found on granitic surfaces of bridges from different ages built in the same area (Ourense in NW Iberian Peninsula at 90 km from the sea) under the same environmental and traffic conditions. The most recent bridge was the New Bridge built in the beginning of 20th century and the oldest one was the Roman Bridge with the 1st century AD foundations but its current structure was built in 17th century. The New Bridge has exhibited a greater variety of deterioration forms such as black crusts, carbonate crusts, efflorescence and biological colonization. On the Roman Bridge, black crusts, efflorescence to a greater extent, and flakes associated with salt crystallization processes have been identified. Scanning electron microscopy with energy dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy studies were carried out in order to establish their composition, and optical and electronic microscopies and X-ray microtomography were used to study their morphologies. As a result, anthropogenic factors (industrial activities, traffic pollution and fertilizers) are considered to be the main contributors to crusts, efflorescence and flake formation on both studied substrates (granite ashlars and mortars). To a lesser extent, natural factors (marine influence and bird droppings) should be taken into account.

Silves Castle is located in the Algarve, South of Portugal. Archaeological excavations provided numerous remains of the Islamic presence in this area from the 8th to the 13th c., which could be traced back to the Ommiad, Caliphal, Taifa, Almoravid and Almohad periods. The spectroscopic study of the ceramics, enabled us to discuss their provenance and production techniques. A clear difference in the diffraction patterns of the sherds from the Ommiad period (8th to 9th c.), and the Caliphal period (10th–11th c.) was observed, pointing to imported ceramics in both groups, the latter most likely from Medinat al-Zahra. The origin of the Ommiad ceramics still remains controversial. The samples from the Taifa kingdoms (11th c. period) were characterized as Lisbon productions. The blue and white ceramics studied here (12th–13th c.) are most probably the first samples showing the use of cobalt blue onto a white tin oxide layer made in Portugal.

The number of published studies related to the optimization of lithium extraction from low-grade ores has increased as the demand for lithium has grown. However, no study related to the kinetics of the concentration stage of lithium-containing minerals by froth flotation has yet been reported. To establish a factorial design of batch flotation experiments, we conducted a set of kinetic tests to determine the most selective alternative collector, define a range of pulp pH values, and estimate a near-optimum flotation time. Both collectors (Aeromine 3000C and Armeen 12D) provided the required flotation selectivity, although this selectivity was lost in the case of pulp pH values outside the range between 2 and 4. Cumulative mineral recovery curves were used to adjust a classical kinetic model that was modified with a non-negative parameter representing a delay time. The computation of the near-optimum flotation time as the maximizer of a separation efficiency (SE) function must be performed with caution. We instead propose to define the near-optimum flotation time as the time interval required to achieve 95%–99% of the maximum value of the SE function.

A Cu 12 Sb 3.6 Bi 0.4 S 10 Se 3 glass was prepared by melt spinning and crystallized by heat treatments at selected temperatures, the total preparation procedure taking less than one day. The sample characterization by powder X-ray diffraction, scanning and transmission electron microscopy complemented with EDS indicate the formation of compact materials, with a tetrahedrite relative weight fraction higher than 90% when treated at temperatures close to the crystallization peaks (∼200° C). Selenium enters the tetrahedrite structure, while bismuth precipitates in submicron and nanosized spherical shape phases depleted in copper and enriched in antimony, sulfur and selenium (when compared with the matrix composition). The characterization of electrical transport properties (electrical resistivity and Seebeck coefficient) indicate a behavior similar to that obtained by other methods on Cu 12 Sb 4 S 13 , with a maximum power factor of ∼400 μW/K 2 m at room temperature.

Tissue engineering is responsible for developing biological substitutes that restore, maintain or improve tissue function. A solution to achieve this is to implant scaffolds on the affected tissue. These support structures will be responsible for cell protection, oxygenation and nutrition, while supporting mechanical loads during the regeneration process. They should also be biodegradable in order to be gradually replaced by healthy tissue. From the available scaffolds manufacturing techniques, fused filament fabrication has been used recently. This technique does not use organic solvents and has the ability to produce complex geometries. In this paper the influence of manufacturing parameters was assessed. Different temperatures, extrusion speeds, filament offset distances and layer thicknesses were tested and their effect analyzed regarding scaffold morphology and mechanical properties. By decreasing the filament offset distance, three different scaffolds porosities were obtained, increasing the mechanical properties. Combining higher printing temperatures with slow extrusion speeds and low layer thickness, a maximum yield stress of 28 ​MPa and apparent compressive modulus of 942 ​MPa were obtained. With these preferred parameters, two different manufacturing schemes and geometries were tested. While using a double layer printing scheme one obtains an average of 70% increase in mechanical properties, using a staggered configuration can decrease mechanical properties up to 84%.

This paper aims to contribute to a better knowledge of the production and rehydration of thermo activated recycled cement (TRC) and its incorporation in cement based materials. To this end, the influence of different factors in the fresh and hardened properties of mortars with TRC was analysed, such as the water/binder ratio, the treatment temperature, incorporation percentage and particle fineness of TRC. Thermogravimetry, X-ray diffraction, isothermal calorimetry, scanning electron microscopy and 29Si nuclear magnetic resonance spectroscopy were carried out to better understand the hydration behaviour and microstructure development of TRC mortars. Optimal rehydration properties and strength development were obtained for recycled cement thermo activated at 600–800 °C. Binders with CEM I 42.5R and 20, 50 and 100% TRC could be framed in the European normative strength classes 52.5, 42.5 and 32.5, respectively. The main obstacles that hinder the application of TRC are its low setting time and high water demand. However, the water demand and setting time were not significantly affected for up to 50% TRC incorporation. Moreover, the mechanical strength was little affected for up to 20% TRC replacement and was only 12% reduced for 50%TRC incorporation. Therefore, TRC proved to be a very promising supplementary cementitious material for cement replacement.

The construction sector consumes 95% of the total production of gypsum due to its multiple applications. Gypsum plaster is one of the most common indoor coating material (pastes and mortars), but it can also be used in prefabricated products like plasterboards, blocks and decorative elements. Gypsum waste recycling provides a solution to an important environmental problem from the use of gypsum plaster, which is the generation of large amounts of wastes at different phases (production, construction, rehabilitation and demolition). This paper studies two different replacement alternatives of natural gypsum: Flue Gas Desulphurization (FGD) gypsum and gypsum waste obtained from industrial plasterboard production. The influence of the previous types, amounts of waste (25, 50, 75 and 100 wt%) and different heating temperatures (100 °C, 150 °C and 180 °C) and processes on the workability of gypsum plasters is evaluated and discussed, based on a microstructure analysis using XRD and SEM techniques. This research highlights the feasibility, in terms of workability, of using Gypsum Plasterboard Waste (GPW), without any heating process, as a replacement gypsum in plasters. Despite the fact that a higher amount of water was necessary in the production of the mixes, a good workability was achieved. On the other hand, the unfeasibility of using unheated FGD as a constituent of plasters was demonstrated. However, a good performance, in terms of workability, of the FGD was obtained when the powder was subjected to a heating process at 180 °C during 6 h.

A detailed archaeometric study of pottery was made of a fifteenth-to-sixteenth-century kiln located inside the walls of the Castle of Alenquer. The locally collected sherds are lead glazed, and mostly exhibit a green or dark yellow decoration. Only in one case, a fragment of a bowl, tin oxide was detected in the white glaze. Pastes from the ceramics of the Alenquer kiln were spectroscopically characterized in terms of their mineralogical and elemental composition. This pottery was fired twice, the first time at high temperatures to produce the biscotto, and the second time at lower temperatures to glaze the ceramics. Although only one type of raw material collected locally was used, two types of ceramic pastes were detected and organized into two groups: one produced at about 850 °C and another at about 950 °C. Pastes from Group 1 were converted into Group 2 pastes whenever the temperature of the kiln was raised from 850 to 950 °C, as confirmed by firing Group 1 pastes in an oven. These results were compared with those obtained for coeval ceramics, namely at Santo Antonio da Charneca and Mata da Machada. Both kilns were located on the south shore of the river Tagus (Lisbon), as previously reported. The first archaeometric study of ceramics produced in the kiln of Alenquer, (Portugal, fifteenth to sixteenth centuries) is reported, with the use of surface spectroscopies techniques, namely micro-Raman. Significant differences were found from two coeval kilns also located at the Tagus basin, Santo Antonio da Charneca and Mata da Machada.

In this work, the initial results of the type testing of the LiF:Mg,Cu,P (TLD-100H) whole-body personal dosemeters are presented. An assessment of reproducibility, linearity of the response, the residual signal as a function of the dose, energy and angular dependence of the response was performed. In general, the dosemeters show good reproducibility for different dose values and a linear behaviour for a range between 0.1 and 300 mSv. The detection limits obtained are lower than 50 μSv. The system presents a good energy and angular response for different radiation qualities.

The oldest kilns producing tin glaze wares discovered in the region of Lisbon were located in the south shore of Tagus river at Santo Antonio da Charneca (SAC) and Mata da Machada (MM). Firing this type of pottery from the fourth quarter of the 15th century to mid-16th century, they were located about 20 km away from central Lisbon. Many other examples of ceramics produced in Lisbon workshops from that period are also known and exist in museums or archaeological collections, in spite of the fact that only one kiln dated from that period was found in Lisbon until now. Therefore, the spectroscopic characterization of ceramics found in Lisbon archaeological contexts (attributed to Lisbon workshops) – and also from SAC or MM – was needed and was performed here. Sherds representative of these faience production centres in the Lisbon region dated from the 16th/17th centuries were studied with the use of non-invasive spectroscopies, namely micro-Raman, Ground State Diffuse Reflectance Absorption (GSDR) and X-ray fluorescence emission (XRF). X-ray diffraction (XRD) experiments were also performed. Also clays were collected both in the North and South shores of the river Tagus, as much as possible from the same clay sources as used in the initial workshops. The obtained results evidence a clear similarity in the pastes of the pottery of the Lisbon region, quartz, gehlenite and diopside (or augite) being the major components. Clays are from Miocene origin, but differences between the ceramic pastes were detected pointing to the use of several clay sources. The spectroscopic trend exhibited at SAC and MM pottery is remarkably different, quartz being the major component of those pastes, and clays are from Pliocene origin.

11 páginas.-- 6 figuras.-- 1 tablas- 67 referencias.-- Supplementary information accompanies this paper at https://doi.org/10.1038/s41598-018-20393-2, Microbial diversity in lava tubes from Canary Islands (Spain) has never been explored thus far offering a unique opportunity to study subsurface microbiology. Abundant yellow coloured mats developing on coralloid speleothems in a lava tube from La Palma Islands were studied by next-generation sequencing and DNA/RNA clone library analyses for investigating both total and metabolically active bacteria. In addition, morphological and mineralogical characterization was performed by field emission scanning electron microscopy (FESEM), micro-computed tomography, X-ray diffraction and infrared spectroscopy to contextualize sequence data. This approach showed that the coralloid speleothems consist of banded siliceous stalactites composed of opal-A and hydrated halloysite. Analytical pyrolysis was also conducted to infer the possible origin of cave wall pigmentation, revealing that lignin degradation compounds can contribute to speleothem colour. Our RNA-based study showed for the first time that members of the phylum Actinobacteria, with 55% of the clones belonging to Euzebyales order, were metabolically active components of yellow mats. In contrast, the DNA clone library revealed that around 45% of clones were affiliated to Proteobacteria. Composition of microbial phyla obtained by NGS reinforced the DNA clone library data at the phylum level, in which Proteobacteria was the most abundant phylum followed by Actinobacteria., Tis research was supported by the Spanish Ministry of Economy, Industry and Competitiveness (MINEICO), project CGL2013–41674-P. J.L.G-P. and A.Z.M. were supported by a PhD fellowship (BES-2014–069587) and a “Juan de la Cierva – Incorporación” post-doctoral contract (IJCI-2014–20443) from the MINEICO, respectively. Te Portuguese Foundation for Science and Technology (Strategic project UID/ECI/04028/2013) are also thanked for fnancial support. Te authors would like to thank the assistance during the feld work and photographic contributions in La Palma lava tubes of the speleologist Octavio Fernandez. We gratefully acknowledge the collecting permissions granted by the staf of Caldera del Taburiente National Park (La Palma Island, Spain).

The main factors that affect the extraction of metals from spent lithium-ion batteries by acid leaching using H2SO4, and sodium metabisulphite, were evaluated and optimized through a set of experiments, framed by a techno-economic approach. The maximum value of the profit response was obtained with the highest possible values of acid concentration (2.5 M) and time (2 h), a liquid/solid ratio of 5 L/kg, and the lowest possible value of temperature (40 degrees C). After leaching, the electrodes active material contained in the metals decreased, while it was still significant in the graphite, as observed by scanning electron microscopy-energy dispersive spectrometry and x-ray powder diffraction. Even though the performed economic evaluation was a summarized outline it can be considered suitable to compare different leaching conditions and to determine the possible best combinations of factors that can optimize the profit response. info:eu-repo/semantics/publishedVersion

Lithium extraction from hard-rock ores has regained importance due to the increased demand for this metal to supply the growing battery market. Therefore, several studies have been focused on the lithium extraction from ores, however, leaching and purification steps are sparsely studied. Thus, the objective of this study was to evaluate the main factors affecting the water leaching step and the subsequent purification operations for lithium recovery from a lepidolite concentrate, which was processed by mechanical activation and sulphuric acid digestion. In the leaching step, among the variables studied, only one, the leaching temperature, showed a significant effect on the lithium extraction, taking into account the range of values tested. Thus, the recommended operating value for the leaching time and the L/S ratio is the minimum, while for the leaching temperature is 50°C. After optimizing the leaching operation, the purification of the leachate, by neutralization, was thoroughly performed by efficient removal of impurities (Fe, Al, Mn and Ca), allowing to obtain lithium carbonate as final product, as well as other relevant by-products, such as rubidium and potassium alums. info:eu-repo/semantics/publishedVersion

The hydrometallurgical extraction of metals from spent lithium-ion batteries (LIBs) was investigated. LIBs were first dismantled and a fraction rich in the active material was obtained by physical separation, containing 95% of the initial electrode, 2% of the initial steel and 22% of plastic materials. Several reducers were tested to improve metals dissolution in the leaching step using sulphuric acid. Sodium metabisulphite led to the best results and was studied in more detail. The best concentration of Na2S2O5 was 0.1 M. The metals dissolution increased with acid concentration, however, concentrations higher than 1.25 M are unnecessary. Best results were reached using a stirring speed of 400 min(-1). The metals leaching efficiency from the active material (Li, Mn, Ni, Co) increased with the temperature and was above 80% for temperatures higher than 60 degrees C. The dissolution of metals also rose with the increase in the liquid/solid ratio (LAS), however, extractions above 85% can be reached at LAS as lower as 4.5 L/kg, which is favourable for further purification and recovery operations. About 90% of metals extraction can be achieved after only 0.5 h of leaching. Sodium metabisulphite can be an alternative reducer to increase the leaching of Li, Mn, Co, and Ni from spent LIBs. info:eu-repo/semantics/publishedVersion

Purpose– This paper aims to study the influence of the binder saturation level on the accuracy and on the mechanical properties of three-dimensional (3D)-printed scaffolds for bone tissue engineering.Design/methodology/approach– To study the influence of the liquid binder volume on the models accuracy, two quality test plates with different macropore sizes were designed and produced. For the mechanical and physical characterisation, cylindrical specimens were used. The models were printed using a calcium phosphate powder, which was characterised in terms of composition, particle size and morphology, by X-ray diffraction (XRD), laser diffraction and Scanning electron microscopy (SEM) analysis. The sample’s physical characterisation was made using the Archimedes method (porosity), SEM, micro-computer tomography (CT) and digital scan techniques, while the mechanical characterisation was performed by means of uniaxial compressive tests. Strength distribution was analysed using a statistical Weibull approach, and the dependence of the compressive strength on the porosity was discussed.Findings– The saturation level is determinant for the structural characteristics, accuracy and strength the models produced by three-dimensional printing (3DP). Samples printed with the highest saturation showed higher compressive strengths (24 MPa), which are over the human trabecular bone. The models printed with lower saturations presented the highest accuracy and pore interconnectivity.Originality/value– This study allowed to acquire important knowledge concerning the effects of shell/core saturation on the overall performance of the 3DP. With this information it is possible to devise scaffolds with the required properties for bone scaffold engineering.