Il dialogo di civiltà alla luce dell’esperienza kazakistana

La Repubblica del Kazakhstan, che ha acquisito l’indipendenza nel 1991 in seguito alla dissoluzione dell’URSS, è uno dei Paesi più variegati del mondo sotto il profilo della composizione nazionale e religiosa: sul suo vasto territorio si contano infatti oltre 130 gruppi etnici e 40 confessioni all’interno di una popolazione di circa 16 milioni di abitanti. Una realtà che si potrebbe definire tanto complessa quanto poco conosciuta, specialmente in Italia. Il testo si concentra sulla strategia perseguita dal governo kazako (la c.d. unità nella diversità, o in alcuni documenti l’unità attraverso la diversità), che a partire dall’indipendenza si è trovato a governare in piena autonomia su una realtà estremamente eterogenea. La scelta delle autorità è stata quella di puntare sulla costruzione di una identità “kazakistana”, ossia civile, laica e sovranazionale, che ambisce a garantire una convivenza pacifica proponendosi come modello di dialogo fra civiltà. La distinzione tra identità “kazaka” (cioè etnicamente e linguisticamente connotata) e identità “kazakistana” (chiamata ad accogliere popoli diversi sotto una cittadinanza esplicitamente multiculturale) costituisce il cuore di questa strategia

Effect of soda-lime glass on sintering and technological properties of porcelain stoneware tiles

The feasibility of waste glass recycling in ceramic tile production was assessed with special reference to fully vitrified products (porcelain stoneware). Soda-lime float or container glass was introduced, in replacement of sodic feldspar, in typical porcelain stoneware bodies (up to 10% wt) that underwent a laboratory simulation of tilemaking process, with a technological and compositional characterization of both fired and unfired tiles. Soda-lime glass had no significant effect on semi-finished products, but it influenced remarkably the firing behaviour, increasing shrinkage and closed porosity, decreasing open porosity and bulk density, and lowering mechanical and tribological performances. Waste glass promotes a more effective melting of quartz and a partial dissolution of mullite, leading to a more abundant and less viscous liquid phase, which accelerates the sintering kinetics. In conclusion, soda-lime glass can be used in small amounts (5% or less) with tolerable modifications of technological behaviour and performances of porcelain stoneware tiles

Clinical relevance of silent red blood cell autoantibodies.

.

The Role of counterions (Mo, Nb, Sb, W) in Cr-, Mn-, Ni- and V-doped rutile ceramic pigments. Part 2. Colour and technological properties

Industrial rutile pigments are manufactured using several chromophores: Cr (giving an orange hue), Mn (tan), Ni (yellow) and V (gray); a second element, the so-called counterion (i.e. Mo, Sb, Nb or W) is always added in order to achieve the desired coloration and/or improve the technological properties (e.g. chemico-physical resistance in ceramic bodies and glazes). The colour of these pigments is determined by both metal-ligand charge transfer (Ti4+ <-> O2-) and crystal field effects (transition metals substituting Ti4+ in octahedral coordination). Though the absorbance bands are broad and frequently overlapped, the UV-vis-NIR spectra suggest the occurrence of Cr3+, Mn2+, Mn3+, Ni2+, V3+, and V4+ as chromophores. Rutile pigments are suitable for through-body (up to 1250 degrees C) and glaze applications (up to 1100 degrees C). The best coloration of porcelain stoneware bodies is achieved with Sb or W as counterions, though the higher stability is ensured by Sb, but in the Ti-Ni-W system. The best glaze colours are accomplished by W-bearing pigments, which however are less stable than Nb- or Sb-containing ones, except than for the V + W coupling. This latter represents a new and very interesting Co-free and Cr-free black pigment for low temperature applications

The influence of microstructure on the performance of white porcelain stoneware

In the last years polished white porcelain stoneware tiles, coupling the smooth and glossy surface with the increased body whiteness, get a prominent role on the market. The bright white colour is obtained by adding noteworthy quantity of opacifiers, such as zircon, corundum and spinel. To better understand the complex relationships among the microstructure and the mechanical, tribological and functional behaviour of this class of products, four polished white porcelain stoneware tiles were selected and thoroughly characterized by a wide spectrum of chemico-physical and microstructural analyses. Products exhibit excellent mechanical properties (flexural strength, Young modulus, fracture toughness) with a clear dependence of these properties on porosity and phase composition. Mullite and zircon tend to increase the mechanical performances, through a predominant mechanism of matrix reinforcement, while quartz plays an opposite role

Effect of waste glass (TV/PC cathodic tube and screen) on technological properties and sintering behaviour of porcelain stoneware tiles

In the present work, the effects of TV and PC cathodic tube and screen glasses additions (5 and 10 wt.%) to a porcelain stoneware body, in replacement of feldspar, were evaluated simulating the tilemaking process. The presence of glass allows to preserve good technological and mechanical properties, complying with the latest requirements of the industrial practice. The sintering pattern of the glass-added bodies, evaluated by hot stage microscopy, is modified according to the different glass amount and typology; in particular, cathodic tube glass when present at 5 wt.% brings about a lowering of the maximum densification temperature and of the activation energy

Clinical characteristics and outcome of patients with autoimmune hemolytic anemia (AIHA) uniformly defined as primary by a diagnostic work-up

Primary autoimmune hemolytic anemia (P-AIHA) is a relatively uncommon and hetereogeneous disease characterized by the destruction of red blood cells due to anti-erythrocyte autoantibodies (AeAbs) in the absence of an associated disease [1–3]. Secondary AHIA is frequently associated with lymphoproliferative diseases (LD) in particular, chronic lymphocytic leukemia, aggressive or indolent lymphomas, autoimmune disorders, malignancies other than lymphoid, and infections [1,2,4]. On the hypothetical assumption that in a significant proportion of cases defined as P-AIHA the clinical heterogeneity could be due to an ignored associated disease, we retrospectively analyzed the clinical characteristics and outcome of patients with a diagnosis of P-AIHA based on a diagnostic work-up aimed at excluding or identifying an associated disease. ..

Zeolite-feldspar epiclastic rocks as flux in ceramic tile manufacturing

Low-cost, naturally-occurring mixtures of feldspar and zeolite occurring in epiclastic rocks are promising substitutes for conventional quartz-feldspathic fluxes in ceramic bodies, since their fusibility and low hardness are expected to improve both grinding and sintering. Three epiclastic outcrops, with a different zeolite-to-feldspar ratio, were characterized (XRPD, fusibility) and tested in porcelain stoneware bodies; their behaviour during processing was appraised and compared with that of a reference. The addition of an epiclastic rock (20 wt.%), replacing rhyolite and aplite fluxes, brought about some significant advantages, mainly represented by better grindability, lower firing temperature with improved mechanical strength and lower porosity. Disadvantages concern increased slip viscosity, worse powder compressibility, resulting in larger firing shrinkage, and a darker colour of the tiles due to relatively high amounts of iron oxide