1,423 research outputs found
Materials selection for green buildings: which tools for engineers and architects?
The selection of building materials plays a key role in the achievement of the 'Green Buildings' target and is performed both at an early stage of the design process (when general and strategic choices concerning the building are made) and at the working plan (when materials available on the market are selected). The latter aspect is important exactly as the first one for the actual fulfilment of 'greenness' requirements, but architects and engineers in charge of this choice often lack of evaluation tools supporting them in materials' selection. In the present paper, after
a brief discussion about the critical aspects of the definition of 'green building materials', the tools presently available for the selection of building materials are overviewed and discussed, with particular attention to the selection of materials at the working plan stage. The applicability of such tools is therefore discussed, with particular reference to the Italian market
Consolidation of porous carbonate stones by an innovative phosphate treatment: Mechanical strengthening and physical-microstructural compatibility in comparison with TEOS-based treatments
For preservation of stones used in Cultural Heritage, affected by weathering processes that threaten their cohesion and mechanical properties, the application of consolidants is a common practice. However, available consolidating products generally exhibit some drawbacks that hinder their performance, in terms of either mechanical efficacy, compatibility with the substrate and/or durability. Ethyl silicate is currently the most widely used among stone consolidants; nevertheless, its reduced efficacy on calcitic substrates, together with its temporary hydrophobicity, its tendency to crack and its common formulation with volatile organic solvent, make the research for alternative consolidants for carbonate stones necessary. In this paper, a recently proposed new consolidation treatment based on the formation of hydroxyapatite inside the stone was tested on two different porous carbonate stones (Globigerina Limestone and Giallo Terra di Siena), and compared with TEOS-based treatments, frequently used for the consolidation of these lithotypes. The results show that the hydroxyapatite treatment exhibits a good efficacy in terms of mechanical properties and, compared to TEOS, it causes less pronounced alterations in open porosity and water transport properties. This makes the new treatment a potentially valid alternative to TEOS, especially in those situations where the possible presence of water behind the consolidated layer (e.g. in case of rising damp, condensation or infiltration) might threaten the durability of the consolidation intervention
A gastronomia como elemento cultural, símbolo de identidade e meio de integração
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Consolidation of sugaring marble by hydroxyapatite: some recent developments on producing and treating decayed samples
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
Preliminary study on the use of ammonium phosphate for the conservation of marble-imitating gypsum-stuccoes
In this study, a novel method for consolidation and improvement of resistance to water of gypsum-stuccoes was preliminarily investigated. The idea is treating gypsum with an aqueous solution of diammonium hydrogen phosphate (DAP, (NH4)2HPO4) to form hydroxyapatite (HAP, Ca10(PO4)6(OH)2), which has much lower solubility than gypsum. Tests carried out on gypsum paste samples, manufactured to resemble historic stuccoes, showed that, after treatment with the DAP solution, a significant improvement in mechanical properties was achieved and brushite (CaHPO4∙2H2O) was formed (alongside some other by-products, that can be removed by an additional poultice treatment). Even if brushite is more soluble than HAP, still its formation is expected to be beneficial for stuccoes conservation, as brushite is significantly less soluble than gypsum
Durable self-cleaning coatings for architectural surfaces by incorporation of TiO2 nano-particles into hydroxyapatite films
To prevent soiling of marble exposed outdoors, the use of TiO2 nano-particles has been proposed in the literature by two main routes, both raising durability issues: (i) direct application to marble surface, with the risk of particle leaching by rainfall; (ii) particle incorporation into inorganic or organic coatings, with the risk of organic coating degradation catalyzed by TiO2 photoactivity. Here, we investigated the combination of nano-TiO2 and hydroxyapatite (HAP), previously developed for marble protection against dissolution in rain and mechanical consolidation. HAP-TiO2 combination was investigated by two routes: (i) in series application of HAP followed by nano-TiO2 (“H+T”); (ii) simultaneous application by introducing nano-TiO2 into the phosphate solution used to form HAP (“HT”). The self-cleaning ability was evaluated before and after prolonged exposure to simulated rain. “H+T” and “HT” coatings exhibited much better resistance to nano-TiO2 leaching by rain, compared to TiO2 alone. In “H+T” samples, TiO2 nano-particles adhere better to HAP (having flower-like morphology and high specific surface area) than to marble. In “HT” samples, thanks to chemical bonds between nano-TiO2 and HAP, the particles are firmly incorporated in the HAP coating, which protects them from leaching by rain, without diminishing their photoactivity and without being degraded by them
The Master in International Health of Parma University: a possible model of sanitary cooperation with developing Countries
The Master in “International Health and Medicine for Cooperation with Developing Countries” was established by CUCI, based on the evaluation that many health facilities and hospitals in the low-middle income Countries are not properly equipped to face daily emergencies.
The objective of the Master’s program is to train doctors with multi-sector skills, necessary to operate in healthcare ambulatories, hospitals and medical districts, characterized by poor infrastructures and management systems, that are typical in areas of high-poverty, facing cases of emergencies of various entities.
The Italian Ministry of Foreign Affairs and International Cooperation is funding a number of scholarships for the best candidates classified in the final selection rating and residing in African Countries. The Course is also open to Italians who wish to extend their professional skills in order to work in resource-constrained settings.
The Master course lasts one year and includes lectures, seminars, videoconferencing and internships both at the University Hospital of Parma and in other Structures / Laboratories. The final work includes a scientific section and a project work for future collaboration with the Countries from which the doctors come from.
Besides the various fields of medicine, other important themes are addressed in the course, like guidelines for hospital managements, health cooperation, development, prevention strategies.
Why this Master could be a model of sanitary cooperation? The WHO and the Geneva Foundation for Medical Education and Research provide scientific support and they are involved in the teaching programme; the physicians formed in the course, once back in their Countries, are expected to facilitate training of the local staff (physicians, nurses and auxiliary personnel) and to continue collaboration; the project allows strengthening of partnerships with other Universities, Ministries, local and international Associations, NGO.
The feedback of the participants who have attended the previous editions will also be discussed
The VOLATILE4ARCHAEO project: A technical report for conservators
The project VOLATILE4ARCHAEO (Investigation of Volatile Binding Media in Temporary Consolidation of archaeological materials) was funded by the European Commission within the call H2020-MSCA-IF-2020 of the Marie Skłodowska-Curie Actions (Grant Agreement n. 101031224) (https://cordis.europa.eu/project/id/101031224). Volatile binding media (VBM) are used to protect fragile heritage materials during transport or other high-risk operations. Cyclododecane (CDD) is currently the most used temporary consolidant. Still, this material exhibits some limitations, such as its possible toxicity for humans and the environment, its low flashpoint posing inflammation risks, and the fact that it provides a single sublimation rate, which makes it not suitable for all the climates and applications. The EU-funded VOLATILE4ARCHAEO project investigated alternative VBM, alone and mixed with CDD. Sublimation rate, interaction and compatibility with various substrates, and presence of residues were tested. The project provided several options for variable-term consolidation with VBM and experimental data on their performance, including testing on real historical objects. This technical report constitutes an overview of the results for conservators
Consolidation of porous carbonate stones by an innovative phosphate treatment: mechanical strengthening and physical-microstructural compatibility in comparison with TEOS-based treatments
For preservation of stones used in Cultural Heritage, affected by weathering processes that threaten their cohesion and mechanical properties, the application of consolidants is a common practice. However, available consolidating products generally exhibit some drawbacks that hinder their performance, in terms of either mechanical efficacy, compatibility with the substrate and/or durability. Ethyl silicate is currently the most widely used among stone consolidants; nevertheless, its reduced efficacy on calcitic substrates, together with its temporary hydrophobicity, its tendency to crack and its common formulation with volatile organic solvent, make the research for alternative consolidants for carbonate stones necessary. In this paper, a recently proposed new consolidation treatment based on the formation of hydroxyapatite inside the stone was tested on two different porous carbonate stones (Globigerina Limestone and Giallo Terra di Siena), and compared with TEOS-based treatments, frequently used for the consolidation of these lithotypes. The results show that the hydroxyapatite treatment exhibits a good efficacy in terms of mechanical properties and, compared to TEOS, it causes less pronounced alterations in open porosity and water transport properties. This makes the new treatment a potentially valid alternative to TEOS, especially in those situations where the possible presence of water behind the consolidated layer (e.g. in case of rising damp, condensation or infiltration) might threaten the durability of the consolidation intervention
Bowing of marble slabs: can the phenomenon be arrested and prevented by inorganic treatments?
Bowing of thin marble slabs is a phenomenon affecting both historic monuments and modern buildings. In spite of the ubiquity and destructiveness of this phenomenon, no fully satisfactory treatment is currently available to arrest and/or prevent bowing. In this study, a treatment based on formation of hydroxyapatite (HAP) was investigated as a possible route to arrest and possibly prevent bowing of Carrara marble slabs. Four different formulations of the HAP-treatment were tested and compared to ammonium oxalate and ethyl silicate (widely used in the practice of marble conservation). The treatments were applied onto pre-weathered and unweathered specimens to investigate their ability to arrest and prevent bowing, respectively. Marble behavior was studied in terms of residual strain and bowing after thermal cycles up to 90°C in dry and wet conditions. Marble cohesion was assessed before and after the thermal cycles by ultrasound. The HAP-treatments exhibited promising results, as the residual strain and the bowing after the cycles were always lower or equal to the untreated references, while marble cohesion was always higher. Surprisingly, ammonium oxalate caused marked worsening of marble thermal behavior. In the case of ethyl silicate, most of the initial benefit after consolidation was lost after the thermal cycles. In general, the results of the study point out the importance of evaluating marble thermal behavior to assess the suitability of any conservation treatment and suggest that treatments able to strengthen marble without causing excessive pore occlusion and stiffening are preferable to enhance durability to thermal cycles
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