Papers by Marcello Romagnoli
Porcelainized stoneware is an extremely hard and homogeneous unglazed ceramic material obtained b... more Porcelainized stoneware is an extremely hard and homogeneous unglazed ceramic material obtained by fastfiring of kaolinitic ceramic bodies containing a large amount of fluxes. The obtained tiles, available in a large variety of colours, shape size and surface finish, are characterized by very low porosity (<0,3wt% expressed as water absorption) and are ideal for heavy-traffic areas subject to mechanical and chemical stresses. Porcelainized stoneware tiles offer alternative valid (and in many cases necessary) solutions to the traditional glazed tiles either for interiors or for exteriors both in modern or classic constructions for flooring and covering.El gres porcelánico es un material cerámico muy duro y homogéneo, no vidriado en su superficie, obtenido por cocción rápida de composiciones ricas en caolinita, conteniendo una gran cantidad de fundentes. Las plaquetas de pavimentos que se obtienen son de una variedad muy extensa en aspectos, diseños y colores, caracterizándose, fun...
Encyclopedia of Thermal Stresses, 2014
This book provides an updated state-of-the-art review on new developments in alkali-activation. T... more This book provides an updated state-of-the-art review on new developments in alkali-activation. The main binder of concrete, Portland cement, represents almost 80% of the total CO2 emissions of concrete which are about 6 to 7% of the Planet’s total CO2 emissions. This is particularly serious in the current context of climate change and it could get even worse because the demand for Portland cement is expected to increase by almost 200% by 2050 from 2010 levels, reaching 6000 million tons/year. Alkali-activated binders represent an alternative to Portland cement having higher durability and a lower CO2 footprint.
CLEAN - Soil, Air, Water, 2014
ABSTRACT A clean and cheap procedure for the synthesis of zeolites is presented, using glass and ... more ABSTRACT A clean and cheap procedure for the synthesis of zeolites is presented, using glass and aluminum wastes as starting materials. The products are aluminosilicate materials with a high cation exchange capacity (CEC: 259–389.5 meq/100 g) containing 25–30% of crystalline zeolites. Since the synthesized materials are free of potentially toxic elements, they could be safely used for environmental and agricultural applications. More specifically, a material containing 30% of zeolite A has been synthesized at 60 °C in one week, using NaOH as mineralizing agent. About 15% of zeolite A has been obtained at room temperature in 6 months. When KOH was employed, 25% of edingtonite has been produced in the final material after 1 week at 90 °C. All the materials have been characterized for crystallinity, crystal morphology, particle size, pore size, surface area, and CEC. The whole process has been designed with the aim to recycle useful waste materials and reduce at minimum energy consumption and the production of harmful greenhouse gases.
En este trabajo se presentan los resultados obtenidos a partir de la caracterización y el estudio... more En este trabajo se presentan los resultados obtenidos a partir de la caracterización y el estudio del comportamiento reológico de suspensiones de fritas cerámicas para la elaboración de esmaltes para baldosas de monococción porosa. En particular se evidencian los efectos que los distintos componentes y aditivos, ejercen sobre los parámetros reológicos que controlan las fases de preparación y de aplicación. El presente estudio se ha desarrollado usando la viscosimetría rotacional como técnica de estudio, para evaluar el comportamiento reológico de los esmaltes, por medio del análisis de curvas de flujo en un amplio intervalo de viscosidades (1-10 4 cP). Las pruebas reológicas ó fueron hechas en flujo continuo que aproxima el efecto de cizalla y reproduce bastante bien las condiciones de preparación y aplicación de los esmaltes.
Materials Research Bulletin, 2009
Nano-size Al2O3–polyetheretherketone(PEEK) composite thick films have been prepared on stainless ... more Nano-size Al2O3–polyetheretherketone(PEEK) composite thick films have been prepared on stainless steel substrates from non-aqueous colloidal suspensions by electrophoretic deposition (EPD). The effects on the deposition efficiency of process parameters, such as the deposition time, the difference of potential applied and their interactions were studied using a neural network approach to develop a quantitative understanding of the system. Furthermore the use
Materiales de Construcción, 1996
ABSTRACT Porcelainized stoneware is an extremely hard and homogeneous unglazed ceramic material o... more ABSTRACT Porcelainized stoneware is an extremely hard and homogeneous unglazed ceramic material obtained by fastfiring of kaolinitic ceramic bodies containing a large amount of fluxes. The obtained tiles, available in a large variety of colours, shape size and surface finish, are characterized by very low porosity (&lt;0,3wt% expressed as water absorption) and are ideal for heavy-traffic areas subject to mechanical and chemical stresses. Porcelainized stoneware tiles offer alternative valid (and in many cases necessary) solutions to the traditional glazed tiles either for interiors or for exteriors both in modern or classic constructions for flooring and covering.El gres porcelánico es un material cerámico muy duro y homogéneo, no vidriado en su superficie, obtenido por cocción rápida de composiciones ricas en caolinita, conteniendo una gran cantidad de fundentes. Las plaquetas de pavimentos que se obtienen son de una variedad muy extensa en aspectos, diseños y colores, caracterizándose, fundamentalmente, por su muy baja porosidad (&lt;0,3wt%, expresado en porcentaje de capacidad de absorción de agua). Estos materiales son ideales para tráfico pesado en áreas sujetas a intensas tensiones mecánicas y químicas. El gres porcelánico ofrece alternativas válidas (y, en muchos casos, soluciones necesarias) a los pavimentos vidriados tradicionales, en interiores o para usos exteriores, ambos con decoraciones modernas o clásicas para suelos o recubrimientos de paredes.
Journal of the American Ceramic Society, 2010
Corrosion of refractories used in glass melting technology is a complex phenomenon involving chem... more Corrosion of refractories used in glass melting technology is a complex phenomenon involving chemical wear (corrosion) and physical/mechanical wear (such as erosion and abrasion) processes as well as thermal shock and spalling. Besides the complexity in the hydrodynamics of a molten silicate bath with which refractory materials are in contact, refractories are polycrystalline heterogeneous materials containing a relatively high porosity. Pores are centers for accelerated corrosion, spalling, and penetration by the hot liquid. In this work, a corrosion study of aluminosilicate refractory crucibles by chromium and calcium oxides during the melting of Cr-containing soda lime glasses as a function of temperature (14001-15001C) and glass basicity has been performed. The features and mechanism of the corrosion process were compared and analyzed as a function of glass acidobasicity (pO-index) and of the ratio of network-dwelling cations to A1 31 cations (R). The advantage of the pO-index and DR gap methods to assess refractory corrosion risk as a function of the acidobasicity differential between the refractory glassy phase and the glass melt was demonstrated. The change of the concentrations of glass constituents was monitored by ICP analysis of glass samples and correlated to the observed extent of corrosion. The crystalline composition and microstructure of the refractory materials before and after being corroded were studied by XRD analyses and SEM. Cr-doped corundum was found to be the main crystalline phase in the refractory microstructure and other mixed phases with chromium and aluminum and/or silica, which formed at the boundary layer (interface) between the glasses and the aluminosilicate refractory, were identified. The results provide a useful guide to the selection of refractory materials for application in glass and glass-ceramic manufacture in terms of their corrosion risk.
Journal of Controlled Release, 2004
The crosslinking process of natural macromolecules with microwave energy should have the potentia... more The crosslinking process of natural macromolecules with microwave energy should have the potentiality to overcome the problems due to the toxicity of the residuals of chemical crosslinking agents and moreover of the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;in vivo&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; biodegradation products of the chemical crosslinked macromolecule. To evaluate the effective crosslinking of the gelatin forming the microspheres, the water-soluble fraction at 37 degrees C, the water absorption capability, the free amino and free carboxylic acid groups of the gelatin were determined. The structural change in the gelatin microspheres has been detected by the porosity studies. Moreover, both the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;in vitro&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; biodegradability and the biocompatibility of the gelatin microspheres microwave-treated after a subcutaneous injection into female albino guinea pigs were tested. As the results suggest only the gelatin microspheres microwave-treated for 10 min at an inlet temperature of 250 degrees C could have been modified by the crosslink formation among the macromolecular chains. The gelatin microspheres treated with the microwave energy were very well biodegraded as indicated both by the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;in vitro&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; enzymatic degradation studies and mainly by the histopathological examination. This latter study has also demonstrated the biocompatibility of the gelatin microspheres crosslinked with the microwave energy. In order to evaluate the feasibility of the microwave crosslinking process for pharmaceutical applications, both the drug loading and the drug release processes were evaluated using diclofenac as drug model, either as acidic form or as sodium salt. The microspheres were swollen in aqueous solution of diclofenac sodium salt, followed by a washing procedure with cool water to maintain the sodium salt into the microspheres or with pH 1.5 HCl to induce the diclofenac precipitation. To increase the amount of diclofenac acid form in the microspheres, the procedure was repeated three times washing with pH 1.5 HCl after each swelling process. Both the X-ray diffractometry and thermal analysis investigations showed a different physical state of the two drug forms in the microspheres, i.e. the amorphous state of the sodium salt and the crystalline state of the acidic form. According to the experimental results, the drug is released from gelatin microspheres according to the drug loading and the drug solubility.
International Journal of Applied Ceramic Technology, 2007
Ultrasonic pulse velocity testing was carried out to perform nondestructive quality control of re... more Ultrasonic pulse velocity testing was carried out to perform nondestructive quality control of refractory plates used as substrates in fast firing of porcelain whiteware. Two cordierite-mullite refractory compositions characterized by different microstructure morphologies and crack propagation behavior were investigated after a number of industrial thermal cycles. Ultrasonic velocity measurements were used to determine the presence of internal voids/cracks in the samples, originating from the manufacturing procedure. A brief discussion about the correlation between microstructure, crack propagation behavior, and thermal shock resistance is presented. Empirical models were developed to predict the service life of refractory plates from measured values of ultrasonic velocities on as-received samples.
IAWA Journal, 2007
Anatomical studies were made on the structural and decorative elements of the wooden ceiling of t... more Anatomical studies were made on the structural and decorative elements of the wooden ceiling of the 12 th century Cappella Palatina in Palermo, Sicily, to identify the timbers used, analyse their likely provenance, and discuss the selection criteria used by the builders. One hundred and fifty fragments were examined. Abies sp., Pinus sp., Betula sp., Populus sp. and Fagus sylvatica were found and all are most probably from Sicily. Some of the Abies fragments probably belong to Abies nebrodensis as they have exceptionally long tracheids, very tall rays, and abundant crystals. This species was over-logged in the past and now only 29 trees remain in the Madonie Natural Reserve in Sicily. Abies and Pinus are found in vertical and horizontal painted panels, while Populus, Betula and Fagus were used in smaller parts of the muqarnas (painted niches). The choice of species seems to have been related to original tree size. The large size of the Abies boles meant that quarter sawn panels could be used. Sicilian Abies was highly valued at that time for its wood quality. Special attention was paid to the problem of distinguishing partly degraded Abies and Cedrus woods. However, the scalloped torus in some samples displayed ambiguous features and these samples were therefore classified as Abies/Cedrus.
Construction and Building Materials, 2014
ABSTRACT The importance of flow properties in most handling techniques requires specific characte... more ABSTRACT The importance of flow properties in most handling techniques requires specific characterizations of geopolymer rheology in the fresh state. In this work, a Design of Experiment (DOE) approach was used to evaluate the influence of solid load, temperature and dispersant on apparent viscosity and yield stress of fly ash-based geopolymers. The solid load was found to be the most influential variable on viscosity. An increase in solid load led to an increase in apparent viscosity but also of yield stress. Apparent viscosity was found to have an Arrhenius type relationship with temperature. The influence of dispersant on yield stress and viscosity appeared to be minor.
Summary In this research are presented experimental laboratory and semi industrial scale results ... more Summary In this research are presented experimental laboratory and semi industrial scale results with the purpose to demonstrate that sludges produced during polishing and cut tile processes can be usefully used as a secondary raw materials in bricks bodies. These type of waste don't have chemical and physical features suitable for their introduction in tiles formulations but result specially promising to be used as components of bricks mixtures. Test carried out highlight that their addition (max 20 wt% ) does not change negatively the main technological properties measured (absorption, linear shrinkage, effloresce, etc.) 1. Introduzione Nell'industria delle piastrelle ceramiche si producono elevate quantità di residui provenienti dalle fasi di finitura superficiale (levigatura e taglio). Dai dati raccolti, per il solo 2004 e per le province di Modena e Reggio Emilia, è possibile stimare una produzione complessiva di fanghi da trattamento gres porcellanato di circa 20.000 ton/anno di solido secco. Attualmente lo smaltimento di detti fanghi viene effettuato per conferimento in discarica. Tale rifiuto, pur non costituendo pericolo di inquinamento (CER 10 12 99 Rifiuto derivante dalla fabbricazione di prodotti di ceramica, mattoni, mattonelle e materiali da costruzione "Non specificato altrimenti"- NON pericoloso), rappresenta problemi ambientali ed economici soprattutto a causa degli elevati quantitativi prodotti. Nell'intento di valutare ipotesi di riciclo all'interno di uno specifico comparto industriale, si deve in primo luogo considerare la particolare e complessa composizione dei fanghi; essi, infatti, sono costituiti sia da polvere asportata dalle piastrelle di gres che da polvere derivante dall'usura degli elementi abrasivi ricchi in cemento magnesiaco (ossicloruro di Mg e calcite, dolomite) e carburo di silicio (SiC). A questo tipo di rifiuto, inoltre, vanno associate le polveri derivanti dalle operazioni di
In this work, an approach for numerical modeling of the fracture process of complex materials mic... more In this work, an approach for numerical modeling of the fracture process of complex materials microstructures is presented. It is well known that the relation between a material microstructure and the resulting macroscopic properties is a problem of great practical interest. Thus, we study the effect of the particular microstructure on the fracture mechanism and damage accumulation. To this aim,
American Ceramic Society Bulletin, 1993
During recent years, special attention has been devoted both to solving pollution problems during... more During recent years, special attention has been devoted both to solving pollution problems during the manufacturing of ceramics and to learning how ceramics can themselves be a solution. Waste encapsulation opportunities for structural clay products have been studied. These opportunities affect environmental isolation within the semivitreous matrix of the product and remove and destroy volatile organic components of the waste
Résumé/Abstract The fracture behaviour of ceramic refractory plates was investigated starting fro... more Résumé/Abstract The fracture behaviour of ceramic refractory plates was investigated starting from a statistic of real fractured pieces in terms of frequency and type of fracture. The plates investigated were used in industrial practice as a support for porcelain whitewares. To fully understand the fracture nucleation and propagation in refractory plates, a numerical model was adopted. This approach relies on the finite element method for the investigation of stresses arising upon thermol loading due to firing cycles. Moreover, a fracture criterion ...
American Ceramic Society Bulletin
The four techniques used to measure porosity are examined: mercury porosimetry, helium pycnometry... more The four techniques used to measure porosity are examined: mercury porosimetry, helium pycnometry, image analysis and water absorption. Helium pycnometry allows determination of both open and closed porosity with greatly contained error. It does not however, make a distinction between the two. Image analysis allows determination of the pore size distribution and pore morphology. However, it does not distinguish between closed and open pores. With mercury porosimetry, it is possible to resolve open porosity with excellent precision, however, it remains blind to closed porosity. Finally, water absorption, although simple and inexpensive, does not obtain any results with a good degree of reliability.
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Papers by Marcello Romagnoli