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Mineralogical, chemical-physical characterization of mineral fibers and their interaction with the human body
Viani, Alberto ; Pérez-Estébanez, Marta ; Mácová, Petra
A standardized protocol of analysis of the mineral fibers with a preliminary full mineralogical characterization has never been applied so far. There are thousands of contributions in the literature on specific aspects of the problem but very few attempts to draw a general picture based on a multidisciplinary approach. To the eye of the proposers of the project, this seems to be the only way to reach a conclusive and shared general view at a molecular level of the bio-toxicity of mineral fibers at a structural level. In this first stage of a more vast project, the study of mineral fibers has been conducted using different experimental approaches. Eight samples of mineral fibers have been selected for their economic and social importance with the objective to systematically characterize their structural, physical-chemical characteristics and attain a direct comparison. X-rays diffraction data, micro-Raman and micro-Infrared spectra of some of them were collected at CET.
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The concept of "end of waste" and recycling of hazardous materials: in depth characterisation of the product of thermal transformation of cement-asbestos
Viani, Alberto
Since many decades, the solution to social and technological problems is made possible by the application of innovative concepts or ideas inspired by Nature. Although this might seem a novel approch, it is indeed a very old scientific method. One of the most outstanding examples is represented by the drawings and models realised by Leonardo da Vinci, which reveal how the most famous inventor of the Renaissance period developed his scientific knowledge through the study of nature. The term Nature-inspired actually means “ideas inspired by Nature” and was recently subjected to a sort of speciation process which branched expressions like geo-inspiration, bio-inpiration and many more (Darder et al., 2007). Geoinspiration denotes the wealth of motivations that materials’ scientists can borrow from the mineral world. It can be a powerful tool to solve modern human problems such as the management of wastes, a global concern of the modern world.
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Accuracy of internal and external standard method in quantitative analysis by X-ray powder diffraction
Pérez-Estébanez, Marta ; Viani, Alberto
The X-ray powder diffraction method is known to convey information on the phase composition of samples. Obtaining an accurate quantification of these phases has been long precluded. With the advent of the Rietveld method [1] this became possible. Hedemonstrated the possibility to extract accurate structural information from neutron powder diffraction data. Later, his approach has been extended to x-ray powder diffraction data with successful results. The basics of the Rietveld method lays on the complete exploitation of the whole powder profile without extracting the integrated intensities. The structural information are obtained by fitting the entire profile of the measured diffraction pattern to a calculated diffraction profile. The refinement procedure implements the least square regression and it requires a reasonable scheme of starting values that approximate the real datum.
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Characterisation of historic materials - the case of Tao-I-Kisra Palace (Iraq)
Slížková, Zuzana ; Pérez-Estébanez, Marta ; Viani, Alberto
The aim of this study is the characterization of bricks from the Taq-I-Kisra palace in southern Iraq (ancient Mesopotamian area). The palace is located in the plain of the Tigri river (see Fig. 1). The construction probably started around year 540 AD even if there is some uncertainty about its age. The arched hall on the facade is about 37 m high and is the largest vault ever constructed at the time (see Fig. 2). Originally conceived as an imperial palace, was later used as a mosque by the Arabs before being gradually abandoned. The historical constructions in this area are what remains of the capital of the empire. In accordance with geological data, in the area where the temple was built (and in general in the Mesopotamian area), the most available construction material was mud. Mud bricks were made mainly of clays. In ancient times there is evidence of mixes with sand, water, mud, and organic material, husks or straw.
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Reaction kinetics of magnesium phosphate cements
Viani, Alberto ; Pérez-Estébanez, Marta
Magnesium phosphate cements (MPCs), are a class of new binders developed to reduce the ecological impact of construction. When magnesium oxide reacts with potassium dihydrogen phosphate (KH2PO4) (KDP) in presence of water, crystallization of magnesium potassium phosphate hydrate (MKP) occurs, according to the reaction: MgO + KH2PO4 + 5H2O --> MgKPO4·6H2O. Despite the importance of MPC for a wide range of applications, including rapid concrete repair, recycling of hazardous wastes, waste encapsulation, bone repair, natural fibre composites, no data are available on hydration reaction kinetics.
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Climatic wind tunnel for material and structures investigation
Král, Radomil ; Pospíšil, Stanislav
The paper deals with a description of the new climatic wind tunnel laboratory built in historical city Telcˇ. As a separate unit of the Institute of Theoretical and Applied mechanics of the Academy of Science of the Czech Republic, the tunnel will be used for fundamental research in engineering problems within civil engineering, architecture, heritage care and in other fields where wind effects appear along with further factors. The paper presents essential information about the interior layout of the tunnel together with description of advanced facilities serving for simulation of a strong wind, rain, freeze and solar heat radiation. Fundamental part of the paper is devoted to pressure losses determination. Using two different methods, the principal parts of the tunnel are designed taking into account both the optimal flow characteristics and flow resistance.
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