Search results for "Clay"
showing 10 items of 349 documents
Experimental analysis of the water retention behaviour of shales
2014
Shales are among the most commonly considered geomaterials in current energy-related geomechanical investigations, as they are involved in engineering applications such as the unconventional extraction of natural gas, CO2 sequestration and nuclear waste geological storage. A deep understanding of their behaviour with regard to variations in the degree of saturation is of primary significance for such applications. With the aim to establish a sound protocol for shale retention behaviour analysis, this paper presents an advanced experimental methodology that takes into account the specificities of shales such as small pore size dimensions and the large variations in water potential to be appl…
Shot-clay MX-80 bentonite: An assessment of the hydro-mechanical behaviour
2014
This study presents the results of an experimental study conducted to characterise the hydro-mechanical behaviour of shot-clay MX-80 bentonite. In the shot-clay process, granular bentonite was mixed continuously with water and shot on the walls of a tunnel section at the Grimsel Underground Research Laboratory (URL), in Switzerland. The shot-clay was placed to create a layer of bentonite in direct contact with the host rock to avoid preferential water and/or gas flow along the tunnel wall. Samples for an experimental programme were collected during the shooting. The index properties, microstructural features, swelling potential and water retention properties of the shot-clay were analysed. …
The Role of Anisotropy on the Volumetric Behaviour of Opalinus Clay upon Suction Change
2017
An experimental investigation to analyse the anisotropic volumetric response of shaly and sandy facies of Opalinus Clay upon suction variations is presented. Obtained results demonstrate the different behaviour of the tested facies to a wetting-drying cycle. The shaly facies exhibits higher water retention capacity and stronger volumetric response than the sandy facies. Anisotropic response is experienced by both facies with the strain perpendicular to bedding higher than in the parallel direction. The sandy facies exhibits a more pronounced anisotropic behaviour in particular during the drying phase. A detailed analysis of the response in the two directions with respect to the bedding orie…
Capturing digital data of rock magnetic, gamma-ray and IR spectrometry for in-situ quality control and for the study of the physical–chemical regime …
2014
Abstract Residual kaolin deposits are operated on a worldwide basis. The majority of them is derived from chemical weathering of felsic rocks during the Cenozoic. This is true for the kaolin deposits on the western edge of the Bohemian Massif. Here this type of deposit provides industrial minerals for the ceramic industry in SE Germany. This raw material formed under tropical climatic conditions during the Miocene and Pliocene across a vast peneplain. Only within the Naab-Wondreb Depression, however, were economic accumulations preserved from erosion. Here near Tirschenreuth, kaolin has been mined since its discovery in 1830. The semi-consolidated regolith is composed of quartz and opaline …
Ciprofloxacin carrier systems based on hectorite/halloysite hybrid hydrogels for potential wound healing applications
2021
The design of multifunctional nanomaterials which can help the healing processes of skin, preventing the bacterial infections, is crucial for the development of suitable therapy for the treatment of chronic lesions. The use of clay minerals in wound healing applications is well documented since the prehistoric period and offers several advantages due to their intrinsic properties. Herein, we report the development of ciprofloxacin carrier systems based on hectorite/halloysite (Ht/Hal) hybrid hydrogels for potential wound healing applications. To achieve this objective firstly the ciprofloxacin molecules were loaded onto Hal by a supramolecular and covalent approach. The so obtained fillers …
Halloysite nanotubes filled with salicylic acid and sodium diclofenac: effects of vacuum pumping on loading and release properties
2021
AbstractIn this work, we investigated the effects of the vacuum pumping on both the loading efficiencies and the release kinetics of halloysite nanotubes filled with drug molecules dissolved in ethanol. As model drugs, salicylic acid and sodium diclofenac were selected. For comparison, the loading of the drug molecules was conducted on platy kaolinite to explore the key role of the hollow tubular morphology on the filling mechanism of halloysite. The effects of the pressure conditions used in the loading protocol were interpreted and discussed on the basis of the thermodynamic results provided by Knudsen thermogravimetry, which demonstrated the ethanol confinement inside the halloysite cavi…
Adsorption of dissolved organic matter on clay minerals as assessed by infra-red, CPMAS 13C NMR spectroscopy and low field T1 NMR relaxometry
2011
Abstract Dissolved organic matter (DOM) is a very important environmental constituent due to its role in controlling factors for soil formation, mineral weathering and pollutant transport in the environment. Prediction of DOM physical–chemical properties is achieved by studying its chemical structure and spatial conformation. In the present study, dissolved organic matter extracted from compost obtained from the organic fraction of urban wastes (DOM-P) has been analysed by FT-IR, CPMAS 13C NMR spectroscopy and 1H T1 NMR relaxometry with fast field cycling (FFC) setup. While the first two spectroscopic techniques revealed the chemical changes of dissolved organic matter after adsorption eith…
Presentazione
2013
Il programma di ricerca, partendo dalla terracruda, mira a creare dei materiali nanocompositi, una nuova classe di materiali, caratterizzati da una dispersione delle fasi ultra ne, tipicamente dell’ordine di pochi nanometri; in virtù di questa dispersione, i nanocompositi possiedono proprietà uniche, non condivise dai convenzionali compositi o microcompositi. in altri termini, la ricerca mira a potenziare la terracruda con rinforzi nanostrutturati, allo scopo di migliorare le prestazioni chimico-fisiche e meccaniche del prodotto finale. La proposta di ricerca investe aspetti che riguardano la tradizione culturale e materiale e l’in- novazione come criterio per rinnovare la prassi costruttiv…
La scoperta, sistemazione e conservazione della grande Iscrizione di Gortina, nell'isola di Creta (1884-1921): la protezione delle testimonianze e le…
2013
La scoperta e la conservazione della Grande Iscrizione di Gortina a Creta, da parte degli studiosi italiani, fra la fine del XIX sec. e i primi decenni del XX sec., rappresentò un grande riconoscimento scientifico-culturale per la giovane nazione italiana. Nel passato, l’isola di Creta era stata legata alla Repubblica di Venezia e anche questo rapporto favorì l’invio a Creta del giovane epigrafista F. Halbherr, il quale fra notevoli peripezie rinvenne, assieme all’epigrafista tedesco E. Fabricius, la famosa l’iscrizione nell’antica città di Gortina. L’iscrizione, fra le più antiche e complete finora conosciute in tutta Europa, conteneva le norme sulla famiglia, l’eredità e in generale i dir…
Development and characterization of co-loaded curcumin/triazole-halloysite systems and evaluation of their potential anticancer activity.
2014
Abstract Positively charged halloysite nanotubes functionalized with triazolium salts (f-HNT) were employed as a carrier for curcumin molecules delivery. The synthesis of these f-HNT new materials is described. Their interaction with curcumin was evaluated by means dynamic light scattering (DLS) and UV–vis spectroscopy in comparison with pristine unmodified HNT (p-HNT). The curcumin load into HNT was estimated by thermogravimetric analysis (TGA) measurements, while the morphology was investigated by scanning electron microscopy (SEM) techniques. Release of curcumin from f-HNT, at three different pH values, by means of UV–vis spectroscopy was also studied. Furthermore, different cancer cell …