Alessio Langella | University of Sannio - Benevento (Italy) (original) (raw)

Papers by Alessio Langella

Ceramics International, 2017

Different techniques (X-ray diffraction, field emission scanning electron microscope, colorimetry... more Different techniques (X-ray diffraction, field emission scanning electron microscope, colorimetry, visible-near infrared reflectance spectroscopy) were carried out to investigate the cause of colour changes of traditional ceramic materials. Two clayey materials of different composition, collected in the Bay of Naples, were fired in oxidising atmosphere at different temperatures resulting in different shades of red colour. Hematite is responsible of the reddish hue of ceramics and its nucleation is strictly related to firing temperature and chemical composition of the raw materials. A low CaO concentration allowed hematite to form in higher amounts providing a more intense reddish hue at high firing temperatures (over 950°C). At the highest temperature (1100°C) all samples showed darker colour due to increased size of iron oxide particles. Black core developed in Ca-rich ceramics fired at low temperatures as the short time of firing is insufficient to complete iron oxidation within the matrix, except in those containing high temper amounts. Indeed, microstructural modification occurs due to the presence of discontinuities among temper grains and matrix, which improves the circulation of oxygen in the core of ceramics.

Applied Clay Science, 2017

Bricks are the most common building materials of Madagascar due to the large availability of clay... more Bricks are the most common building materials of Madagascar due to the large availability of clayey raw material, the simple technology of production and the ease of use. The brick production is mainly organised in local workshops close to supplying site of clayey deposit where sediments are extracted, moulded in bricks, dried and then fired in open-air furnaces. Fuel varies from peat soils to wood depending on the local availability. Correspondingly, firing time varies from few days in wood furnaces to some weeks in peat fired furnaces. Samples of bricks and raw materials as well as peat fuel, from four workshops located in central and southwestern Madagascar were collected and analysed to infer the technological skills of the Malagasy traditional brick manufacture. Central Highlands Madagascar workshops use clayey lateritic soils formed from in situ weathering of basement rocks. The main plastic component of these deposits is kaolinite. Also the clayey sediments from southwestern Madagascar have kaolinite along with low-ordered clay minerals and carbonates such as calcite and minor Sr-rich dolomite. As far as fired bricks are concerned, experimental data evidenced quite low firing temperatures (below 600°C) in the two different furnaces, regardless the type of fuel. As far as peat fuel is concerned, its low calorific value along with a large amount of furnace energy dispersion does not allow to achieve the temperatures required to produce good quality bricks, notwithstanding long firing time (some weeks). On the other hand, firewood powdered furnaces, although providing much higher energy and a consequent much shorter firing process (few days), also suffer of diffuse heat dispersions which concur to the bad quality of the final product. The specific energy input calculated for type 1 furnace (peat fuel) ranges between 0.09 MJ/kg and 0.18 MJ/ kg of clayey material thus confirming a rather inadequate firing process for the production of good quality bricks, and a rough estimate indicates that volume ratios between peat and clayey material as low as 1:1 should be used in order to reach "modern" specific energy inputs.

The properties of a non-andic, allophanic Inceptisol (POM1) and two andic, non-allophanic Incepti... more The properties of a non-andic, allophanic Inceptisol (POM1) and two andic, non-allophanic Inceptisols (FLM5 and SPM8), representative of a toposequence on basanite rocks of Mt. St. Antonio (central-western Sardinia, Marghine sub-region), were analyzed to better elucidate factors and processes that lead to a different expression of andic properties and allophane formation in xeric Mediterranean environment. A series of laboratory techniques

Journal of the American Ceramic Society, 2016

Archeological campaigns along the track of the Domitian road in Cuma resulted in the recovery of ... more Archeological campaigns along the track of the Domitian road in Cuma resulted in the recovery of a large amount of potshards and crucible fragments (both open and closed forms), covered with residues of blue and green frits, respectively. Typological analysis of the crucibles combined with mineralogical and petrological analyses on the ceramic body and frit residues revealed that the forms are intimately related to the technological data. Newly formed calcium silicates indicate high firing treatments of crucibles during pigment making (not lower than 950°C). In particular, different working temperatures for the two types of crucibles have been estimated by the presence/absence of sodalite-nosean feldspathoid. This mineral formed after the reaction of Si-Al-rich material (the sintered ceramic body) and alkalis transferred to ceramics via chemical diffusion during the pigment synthesis. Thus, the estimated working temperatures are higher for closed forms (>1100°C) and lower for the open ones (950–1050°C). This different thermal treatment perfectly fits with the temperatures of green and blue pigment synthesis; higher temperatures for green pigments allowed the formation of abundant Cu-bearing glassy phase, whereas, blue pigment is prone to the formation and thermal stability of cuprorivaite crystals (950–1050°C). Moreover, the two frits showed similar recipes (quartz-feldspar-calcite-rich sand) with the exception of more abundant Cu-bearing colorant agent in blue hue and higher proportion of alkaline flux in green frit. The obtained data suggested that crucibles were a fundamental tool for pigment manufacturing, likely one of the best example of ancient technical ceramics, as they permitted controlling the temperatures along with the fuel and the treatment time. Combining analytical and archeological data, the production and the technology of the two colored compounds identified as Egyptian Blue and Green frits in ancient Cuma has been inferred. Finally, considering the Vitruvius excerpt that identified an Egyptian Blue production in Puteoli, the area of production can be widen up to the northern Phlegraean Fields, also including Cumae and Liternum.

Geoarchaeology, 2016

Recent transportation infrastructure works in Naples, Italy, provided important discoveries relat... more Recent transportation infrastructure works in Naples, Italy, provided important discoveries related to the production of pottery in the Hellenistic workshop area of Piazza Nicola Amore. A minero-petrographic investigation was conducted on 35 samples belonging to the widespread Campana A ware and production indicators (clayey raw materials, unfired Graeco-Italic amphorae, kiln wastes, workshop tools). Additional analysis was conducted on black-glaze and common ware samples for comparison. The analyses reveal compositional and technological homogeneity of Campana A ware. Samples are characterized by low CaO content with evidence of both volcanic and sedimentary components, suggesting that different clay sources were properly mixed to prepare a standard recipe. Production indicators, black-glaze and common wares, have a composition well consistent with the calcareous clays from the island of Ischia. Leucite- and garnet-bearing temper from the Somma Volcano were used for the preparation of coarse-grained pastes, unfired Graeco-Italic amphorae, and clayey raw materials, thus suggesting that they represented the clay sources for amphorae production. Our results reveal new technological and socioeconomic aspects of Hellenistic pottery production in the Bay of Naples, in particular for the Campana A ware, now representing a new reference group: Neapolis.

Hematite is responsible of the reddish hue of ceramics and its nucleation is strictly related to firing temperature and chemical composition of the raw materials. A low CaO concentration allowed hematite to form in higher amounts providing a more intense reddish hue at high firing temperatures (over 950 °C). At the highest temperature (1100 °C) all samples showed darker colour due to increased size of iron oxide particles. Black core developed in Ca-rich ceramics fired at low temperatures as the short time of firing is insufficient to complete iron oxidation within the matrix, except in those containing high temper amounts. Indeed, microstructural modification occurs due to the presence of discontinuities among temper grains and matrix, which improves the circulation of oxygen in the core of ceramics.

An experimental pedology research program was started aiming at modeling the potential pedogeniza... more An experimental pedology research program was started aiming at modeling the potential pedogenization of zeolitized tuffs. The present study deals with a medium-term weathering of Phlegraean Yellow Tuff (PYT, with phillipsite>chabazite) and Red Tuff with Black Scoriae (RTBS, with chabazite>phillipsite) under discontinuous treatment by water (W) and by humic acids (HA). Significant amounts of cations, increasing in the sequence Al<Fe<Mg<Ca, were extracted by both water and humic acids. The humic acids showed in all cases the highest extracting efficiency. All cations, especially calcium, were more easily removed from PYT than from RTBS. The only exception was iron which was preferentially removed from RTBS by HA. At the end of the experiment, smectite was not any more detected in the PYT residues. On the whole, the results indicate that PYT is more prone than RTBS to both humic acid and water weathering due to its different mineralogy.

European Journal of Mineralogy, 1999

ABSTRACT Two clinoptilolites from genetically different volcanoclastic formations have been studi... more ABSTRACT Two clinoptilolites from genetically different volcanoclastic formations have been studied. Both deposits are located in the Logudoro region (North-Western Sardinia, Italy) within epiclastic and pyroclastic formations related to calcalkaline volcanic activity. Chemical characterization performed by electron microprobe analysis on both samples showed a quite similar composition ([Si/(Si+Al)] = 0.81√0.82), with the exception of some extra-framework cations. In particular the epiclastic clinoptilolites turned out to be much higher in Mg content (0.72 vs. 0.26 a.f.u.) and considerably lower in K (1.10 vs. 2.37 a.f.u.) than the pyroclastic clinoptilolites. Previous investigations evidenced a different behaviour of the two clinoptilolite samples towards cation exchange processes and a substantial difference between the theoretical and experimental CEC. In this frame, Rietveld refinements based on synchrotron data allowed to define a different cationic population within the four exchangeable cation sites.

Studies in Surface Science and Catalysis, 2002

ABSTRACT Cited By (since 1996): 2, Export Date: 5 November 2012, Source: Scopus

Periodico di Mineralogia, 2011

Reviews in Mineralogy and Geochemistry, 2001

ABSTRACT

Mineralium Deposita, 1996

... Vico 0.24).15 Ma 3(2) Ch, Ph, S, Cpx, B (1) (4) ... a b 455 Fig. 2. a Mole plot of exchangeab... more ... Vico 0.24).15 Ma 3(2) Ch, Ph, S, Cpx, B (1) (4) ... a b 455 Fig. 2. a Mole plot of exchangeable cation content in chabazites and phillipsites of the Vulsini and Vico districts and b chemical variability of the same phases, D, divalent cations; M, monovalent cations 0.5 0.4-"~" 0.3-e 0 g ...

European Journal of Mineralogy, 2010

The study proposes a model by which a thick succession of volcanic tus can be zeolitized by alte... more The study proposes a model by which a thick succession of volcanic tus can be zeolitized by alteration of pyroclastic material in the presence of sucient eruptive water and at temperatures close to water vapour condensation. In the case of phreatomagmatic products, the model simpli®es interpretation of problematic deposits that exhibit pronounced vertical and lateral variation in lithi®cation grade. A major feature of the model is that thick zeolitized tus can be formed during emplacement of pyroclastic products, in marked contrast to later alteration in an open hydrologic system. Geological, volcanological and mineralogical data for the Neapolitan Yellow Tu, a widespread trachytic pyroclastic deposit outcropping around Campi Flegrei (Southern Italy), have been used to infer the physico-chemical conditions that determined mineral genesis. This tu shows a reduction in lithi®cation grade towards the base, top and with distance from the vent and very variable zeolitization within the lithi®ed portion. We suggest that during initial emplacement the erupted products chilled against the ground, inhibiting zeolite crystallization. During rapid deposition of the thick, wet succession thermal insulation allowed the persistence of elevated temperatures for a time sucient for enhancement of hydration-dissolution processes in the volcanic glass. The highly reactive alkali-trachytic glass quickly buered the acid pH of the system, favouring phillipsite crystallization followed by chabazite nucleation. The variable zeolite content re¯ects ¯uctuating emplacement conditions (e.g. changes in water content and temperature). Cooling of the upper and relatively thin distal deposits inhibited the zeolitization process, thereby preserving the primary unlithi®ed deposit.

Archaeometry, 2009

Samples of table and cooking ware, dating back to the Byzantine period of the ancient Greek colon... more Samples of table and cooking ware, dating back to the Byzantine period of the ancient Greek colony of Cuma, were analysed by optical microscopy, X-ray diffraction, X-ray fluorescence and scanning electron microscopy, in order to reconstruct the main technological properties of these manufactures. The comparison of minero-petrographical data from these samples with those of some kiln wastes allowed us to hypothesize a local manufacture for most of the investigated specimens and to confirm the relative reference groups. A restricted number of samples did not link with the main groups, indicating a regional (or maybe extra-regional) production, in agreement with the widespread circulation of this high-medieval ceramic production in southern Italy.

... Author: Allocca, Francesco; Cappelletti, Piergiulio; De'Gennaro, Maurizio; Pinto, Aldo; ... more ... Author: Allocca, Francesco; Cappelletti, Piergiulio; De'Gennaro, Maurizio; Pinto, Aldo; Langella, Alessio Title Article/Chapter: "I materiali lapidei della facciata dell'Università Federico II a Napoli" Title Translated English: "Investigation on the visible stone materials of the façade of ...