6,290 research outputs found

    Materials and techniques of Art Nouveau architecture in Italy and Portugal: a first insight for an European route to consistent restoration

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    The results of the investigations on building materials and techniques of Casa Major Pessoa, a typical Art Nouveau construction in Aveiro (Portugal), and two coeval Art Nouveau buildings in Bologna (Italy) are presented as a methodological contribution to the restoration of this kind of buildings. This is the first step to ascertain the existence of a common thread between local materials, technologies and architecture in European countries at the same period. A holistic approach was adopted: materials were investigated along with architectural, structural and technological features, in order to achieve a first insight into the Art Nouveau architecture in Europe in particular for its consistent restoration without loss of historical memory

    A new sensorized ceramic plug for the remote monitoring of moisture in historic masonry walls: First results from laboratory and onsite testing

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    The presence of moisture in historic buildings, especially from rising damp, is extremely widespread and severe, causing materials' deterioration, internal discomfort and bad thermal insulation of external walls. Although this phenomenon is widely studied in the literature, the available solutions are frequently only partially effective, also due to the lack of reliable and compatible techniques to monitor the amount of moisture inside porous building materials, especially in heritage buildings where multiple restrictions exist. In this paper, a new sensorized ceramic plug was developed, to be inserted in historic masonry walls for the remote monitoring of moisture. The plug includes a moisture sensor that is currently used for soil irrigation purpose in agriculture and a ceramic envelope of tailored properties. The plug was developed in laboratory following a step-by-step testing program, which took into account both the specific features of the sensor (requiring a strong research effort to be transferred to building materials) and those of historic walls. After a first set of laboratory tests, the sensorized ceramic plug was validated in small-scale laboratory walls and in a real historic masonry in the monumental Certosa cemetery in Bologna, Italy. The results are extremely encouraging, as they show how the new plug can provide valuable information about the rising damp evolution, and in fact, the data were correlated with the changes in the concurrent environmental parameters in the area of the cemetery. The results also suggest some possible measures to improve the sensorized ceramic plug in the near future

    Materiales y tecnologías en la Arquitectura Modernista: casos de estudio de decoración de fachadas en Italia, Portugal y Polonia persiguiendo una restauración racional

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    The results of a diagnostic survey on the materials of representative Art Nouveau buildings in Italy, Portugal and Poland are here presented and compared, as a contribution to their understanding and, hence, to support compatible restoration. In particular, the facade decorations were investigated for the appraisal of their materials and technologies, often neglected in current maintenance/restoration works and so cancelled, leading to a severe loss in architectural image. The ongoing diagnostic campaign, in collaboration among different universities, is aimed to set up a database on materials and technologies of Art Nouveau facade decorations at a European scale, as a technical-scientific background for the highlighting of preservation guidelines

    Consolidation of sugaring marble by hydroxyapatite: some recent developments on producing and treating decayed samples

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    Consolidation of sugaring marble (i.e., marble affected by granular disaggregation) still lacks fully effective solutions. Consequently, the use of an innovative phosphate-based treatment, aimed at bonding calcite grains by formation of hydroxyapatite at grain boundaries, has recently been proposed. In this paper, firstly a novel method for producing artificially decayed marble samples, by contact with a heating plate, is proposed. Then, some results are presented about the effectiveness and the compatibility of two different formulations of the phosphate treatment, differing in terms of concentration of the phosphate precursor (3.0 M or 0.1 M aqueous solutions of diammonium hydrogen phosphate, DAP), possible ethanol addition to the DAP solution and number of DAP solution applications (1 or 2). The results of the study point out that the new weathering method allows to obtain specimens with a gradient in microstructural and mechanical properties with thickness, just like naturally weathered samples. Both phosphate treatments were able to significantly improve marble cohesion, without causing significant changes in thermal behaviour and aesthetic appearance after treatment. The addition of small quantities of ethanol to the DAP solution seems to be a very promising method for favouring HAP formation and improving the treatment performance

    Electrodeposition of hydroxyapatite coatings for marble protection: Preliminary results

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    Surface coatings made of hydroxyapatite (HAP) have been proposed to protect marble artworks from dissolution in rain, originated by the aqueous solubility of calcite. However, HAP coatings formed by wet chemistry exhibit incomplete coverage of marble surface, which results in limited protective efficacy. In this study, electrodeposition was explored as a new route to possibly form continuous coatings over the marble surface, leaving no bare areas. Electrodeposition was performed by placing marble samples in poultices containing the electrolyte (an aqueous solution with calcium and phosphate precursors) and the electrodes. The influence of several parameters was investigated, namely the role of the working electrode (cathode or anode), the distance between the marble sample and the working electrode, the deposition conditions (potentiostatic or galvanostatic), the electrolyte composition and concentration, the applied voltage, and time. The coating morphology and composition were assessed by SEM/EDS and FT-IR. The protective ability of the most promising formulations was then evaluated, in all cases comparing electrodeposition with traditional wet synthesis methods. The results of the study suggest that electrodeposition is able to accelerate and improve formation of HAP coatings over the marble surface, even though the obtained protective efficacy is not complete yet

    SGI como instrumento complementar na avaliação do impacto ambiental da agricultura.

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    Divulga a metodologia, desenvolvida pelo Núcleo, de caracterização e avaliação do impacto ambiental da agricultura, baseada no uso de SGI. O projeto foi executado sobre conjuntos de pequenas propriedades com diferentes sistemas de produção. Na escala municipal articulou espacialmente, via SGI, o uso das terras e os coeficientes técnicos dos sistemas de produção aferentes. Foram geradas 32 cartas de impacto ambiental da atividade agrícola, por recursos e insumos

    Salt-Induced Deterioration on FRP-Brick Masonry Bond

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    In the past decades, several studies have shown how fiber reinforced polymer (FRP) composites are an effective technique to strengthen unreinforced brick masonry structures. However, very little is known about their durability against environmental aggression such as salt attack and freeze-thaw cycles, or elevated moisture content. This paper presents an investigation on influence of salt attack on the stress transfer between the FRP composite and the masonry substrate. In fact, it is well known that, in certain conditions, soluble salts crystallize within the pores of materials, leading to crystallization pressures that may overcome their tensile strength. To investigate this effect, FRP-masonry joints were subjected to salt crystallization cycles according to a conditioning procedure designed by the authors. After conditioning, direct shear tests were conducted on the masonry joints to investigate the interfacial bond between the substrate and the composite. Materials characterization was carried out in order correlate the results of the direct shear tests with the salt distribution within the specimens. For comparison, direct shear tests were conducted on FRP-masonry joints that were not subjected to any cycle and therefore used as control

    Selective Protein Conjugation of Poly(glycerol monomethacrylate) and Poly(polyethylene glycol methacrylate) with Tunable Topology via Reductive Amination with Multifunctional ATRP Initiators for Activity Preservation

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    In this study, we compare poly(glycerol monomethacrylate) (PGMA) of different chain lengths and architectures (linear and two-arm) with poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMA) as an alternative polymer platform for the synthesis of a new generation of protein-polymer conjugates. Mono-and two-arm functional atom-transfer radical polymerization (ATRP) initiators were designed and selectively attached to lysozyme at the N-terminus via reductive amination. Site-specific, grafting from activator regenerated by electron transfer (ARGET) ATRP was carried out in phosphate buffer, and the reaction parameters were optimized to obtain polymer conjugates with predetermined molar mass and topology. The activity preservation under proteolytic and high-temperature conditions showed a clear dependence on the structure of the repeating unit and on the macromolecular architecture. These results highlighted the potential of PGMA as a poly(ethylene glycol) (PEG) alternative for the half-life extension of biotherapeutics. Moreover, this synthetic approach may inspire the design of a new class of protein-polymer conjugates through an optimal combination of macromolecular composition and topology

    Efficacy and safety of felbamate in children under 4 years of age: a retrospective chart review.

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    Background and purpose: To review our experience of the efficacy and tolerability of felbamate in children younger than 4 years. Methods: We used a retrospective chart review to identify 53 children with seizures who were younger than 4 years. Efficacy was evaluated based on the occurrence of responsiveness, defined as seizure frequency reduction of more than 50% for a minimum period of 4 months. Tolerability was based on parent-reported side effects. Results: Twenty-two (41%) patients resulted to be responders and 31 (59%) did not. By univariate analysis, those achieving seizure remission were probably much older, to have a shorter history of epilepsy and a lower frequency of seizures before felbamate therapy. The number of antiepileptic drugs (AEDs) used before felbamate therapy was the only significant predictor of the duration of response to felbamate, with a longer responsiveness to the drug seen in those who were placed under fewer than three AEDs before felbamate compared with those who had taken more than three (median, 16 months vs. 7 months; P < 0.0084). Side effects occurred in 30% of the subjects, but these did not require discontinuation of the drug. Discussion: Felbamate is an effective medication for a wide range of epilepsy syndromes in children younger than 4 years. Although caution is necessary when the drug is used in children, felbamate might represent a possible option for the treatment of epilepsy in this age group. Introduction The incidence of epilepsy is high during the first year of life and it declines steadily during childhood and adolescence. Few of the new antiepileptic drugs (AEDs) are indicated officially for children younger than 4 years [1–3]. None of them is approved for children younger than 2 years [1,3,4]. There is a striking discrepancy between the high incidence of epilepsy in infancy and the relatively few approved AEDs available for this age group [5]. Felbamate (2-phenyl-1,3-propanediol dicarbamate) is a derivative of the anti-anxiety drug meprobamate, exerting additional anticonvulsant and neuroprotective properties [6–8]. The drug has been approved since 1993 for the treatment of several types of epilepsy. Experimental studies suggested that felbamate might inhibit voltage-dependen
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