Search results for "COMPOSITION"
showing 10 items of 2675 documents
Indoor air quality in schools of a highly polluted south Mediterranean area
2019
This study aimed at surveying lower secondary schools in southern Italy, in a highly polluted area. A community close to an industrial area and three villages in rural areas was investigated. Indoor temperature, relative humidity (RH), gaseous pollutants (CO 2 and NO 2 ), selected biological pollutants in indoor dust, and the indoor/outdoor mass concentration and elemental composition of PM 2.5 were ascertained. Temperature and RH were within, or close to, the comfort range, while CO 2 frequently exceeded the threshold of 1000 ppm, indicating inadequate air exchange rate. In all the classrooms, median NO 2 levels were above the WHO threshold value. Dermatophagoides p. allergen concentration…
Verso una nuova città / Towards a new city
2015
Il saggio affronta il tema della città in estensione assumendolo quale strumento per ragionare su sistemi vasti al fine di elaborare macro-visioni, per far in modo che l’architettura produca grandi racconti e superare l’approccio localizzato La questione, di fatto, riattribuisce la capacità di trasformazione del territorio alla Composizione architettonica, che si riappropria del potere di elaborare strategie di trasformazione ragionando sulla natura dello spazio (esistente e da costruire) che devono orientare verso lo sviluppo economico, sociale e culturale, a partire dalla capacità di leggere la bellezza dei luoghi e dalla possibilità di generare nuova bellezza. Questa visione conduce alla…
A reliable and environmentally-friendly liquid-chromatographic method for multi-class determination of fat-soluble UV filters in cosmetic products.
2013
An environmentally-friendly analytical method for the simultaneous determination of 15 fat-soluble ultraviolet (UV) filters currently authorized by the European Union regulation on cosmetic products has been developed. The determination was performed by liquid chromatography with UV spectrophotometric detection. Different parameters, such as type of column, oven temperature, mobile phase composition and flow rate were studied. The best chromatographic separation was obtained under the following conditions: C18 column set at 60°C and gradient ethanol:water (containing 1% formic acid and 20mM of 2-hydroxypropyl-β-cyclodextrin) as mobile phase pumped at 1mL min(-1). 2-Hydroxypropyl-β-cyclodext…
Development of an ICP-IDMS method for accurate routine analyses of toxic heavy metals in polyolefins and comparison with results by TI-IDMS
2000
An inductively coupled plasma isotope dilution mass spectrometric (ICP-IDMS) method was developed as a suitable method - with respect to its sensitivity, precision, accuracy, and time-consumption - for the analysis of toxic heavy metal traces (Pb, Cd, Cr, and Hg) in polyolefins. Results for Pb, Cd, and Cr were compared with those obtained by thermal ionization isotope dilution mass spectrometry (TI-IDMS), which was used as a reference method. Because of its high first ionization potential and its high volatility mercury could not be determined by TI-IDMS. A multi-element spike solution, containing isotopically enriched 206Pb, 116Cd, 53Cr, and 201Hg, was used for the isotope dilution step. D…
Analysis of insoluble silicate: Decomposition with molten sodium hydroxide and determination of Zr(IV) with chloranilic acid in medium-strong acid
1983
A rapid, accurate and precise method for the determination of zirconium in silicates is proposed. Insoluble or sparingly soluble samples are decomposed by means of molten sodium hydroxide. Chloranilic acid is employed as reagent for the spectrophotometric determination of Zr(IV). The limit of detection is 1.2×10−7 M and the relative standard deviation is 0.24%.
Relaciones entre gestión corporativa y crisis financiera en el mercado de capitales español
2015
ResumenLa crisis financiera internacional impulsada por las noticias vertidas en agosto de 2007 ha tenido efectos devastadores sobre los mercados de capitales internacionales. El objetivo de este artículo se centra en verificar, en este contexto de crisis, si las empresas del mercado continuo español generan rendimientos anormales negativos, a la par que investigar qué factores ligados al gobierno corporativo podrían justificar estas anomalías. Nuestros resultados confirman que: a)cuando un mismo sujeto asume dirección ejecutiva y presidencia de la junta, en contra de todo pronóstico, ha tenido efectos beneficiosos sobre la gestión corporativa, permitiendo que esas anomalías se vayan diluye…
GW170817: Measurements of Neutron Star Radii and Equation of State
2018
On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation…
Salvatore Di Piazza. 2011. Congetture e approssimazioni. Forme del sapere in Aristotele (Milano-Udine : Mimesis)
2013
Quel est le statut épistémologique d’une discipline qui, quelquefois, n’atteint pas à ses objectifs ? C’est la question que Di Piazza pose dans Congetture e approssimazioni. Elle concerne la rhétorique et, avec elle, toutes les disciplines qui ont un statut épistémologique comparable, à commencer par la médecine. Trois éléments - disons trois piliers - délimitent le chantier de Di Piazza : la rhétorique, la médecine et la philosophie d’Aristote.Le point de départ est la décision de ne pas se ...
XRF analysis to identify historical photographic processes: The case of some Interguglielmi Jr.’s images from the Palermo Municipal Archive
2017
Abstract In the early period, even though professional photographers worked with similar techniques and products, their artistic and commercial aims determined different choices and led them to follow different, often personal, recipes. For this reason, identification of the techniques through date and name of the photographer or through some visual features like colour, tonality and surface of the image layer, often needs further investigation to be proved. Chemical characterization, carried out in a non or micro destructive way, can be crucial to provide useful information about the original composition, degradation process, realization technique, in obtaining an indirect dating of the ph…
Biofabrication of biosilica-glass by living organisms
2008
Biosilicification is an evolutionarily old and widespread type of biomineralization both in unicellular and multicellular organisms, including sponges, diatoms, radiolarians, choanoflagellates, and higher plants. In the last few years combined efforts in molecular biology, cell biology, and inorganic and analytical chemistry have allowed the first insight into the molecular mechanisms by which these organisms form an astonishing variety of siliceous structures that cannot be achieved by chemical methods. Here we report about the present stage of knowledge on structure, biochemical composition, and mechanisms of biosilica formation, focusing our attention particularly on sponges because of t…