Search results for "site"

Effective medium theory for the low-temperature heat capacity of a metasolid plate

2023

Nanopatterning can be used to strongly control the thermal properties of solids, but theoretical understanding relies often on complex numerical simulations. Here, an analytical theory is derived for the low temperature heat capacity of a nanopatterned phononic crystal plate, focusing on the geometry of a square lattice of cylindrical holes in an isotropic matrix material. Its quasistatic elastic properties were studied using an anisotropic effective medium theory, that is, considering it as a homogenized metasolid. The effective elastic parameters can then be used as an input for an anisotropic plate theory, yielding analytical expressions for the dispersion relations of the three lowest p…

Globally Optimized Equilibrium Shapes of Zirconia-Supported Rh and Pt Nanoclusters : Insights into Site Assembly and Reactivity

2019

Metal−support interfaces form an active site for many important catalytic reactions. The modeling of these interfacial sites calls for approximations to set up a structure model, which in turn may significantly have an impact on studied chemistry and obtained atomistic understanding. Herein, we have employed a density functional theory-based genetic approach to obtain globally optimized nanostructures for Rh and Pt clusters on a ZrO2 support. The analysis of the obtained structures shows that Rh clusters take more compact shapes, whereas Pt prefers elongated and low-symmetry structures. We find that metal−oxide perimeter sites are structurally different, presenting varying Pt and Rh coordin…

Alcohol-Selective Oxidation in Water under Mild Conditions via a Novel Approach to Hybrid Composite Photocatalysts

2015

Abstract The oxidation of alcohols to carbonyl compounds in a clean fashion (i.e., with water as a solvent or under solvent‐free conditions, and using O2 or H2O2 as the primary oxidant) is the subject of considerable research efforts. A new approach for the selective oxidation of soluble aromatic alcohols in water under mild conditions via a novel composite photocatalyst has been developed. The catalyst is synthesized by grafting 4‐(4‐(4‐hydroxyphenylimino)cyclohexa‐2,5dienylideneamino)phenol and silver nanoparticles onto the surface of moderately crystalline titanium dioxide. The titanium dioxide‐based composite was first extensively characterized and then employed in the catalytic oxidati…

NANOARCHITECTURE: A NEW CREATIVITY IN CONSTRUCTION

2015

Object of this work is the construction industry that, until the industrial revolution, has always been a major human activity and nowadays still represents a massive sector of production. Nevertheless, it often deals with coarse components and systems as, in the last century, investments in research remained lower than in other industrial sectors as army, medicine, etc.. Only recently, with the development of technology and the advances in materials science and engineering, a new generation of products, that are both of higher performance and more economically viable, is to be realizing as a competitive route to achieve a real sustainable growth and innovation. Nowadays, the market show hu…

STUDIO DELLE PROPRIETÀ MECCANICHE ED ELETTROMECCANICHE DI NANOCOMPOSITI E NANOFIBRE MEDIANTE APPROCCI NUMERICI

BIONANOCOMPOSITES BASED ON NATURAL POLYMERS AND NANOCLAYS. AN EXTENDED PHYSICO-CHEMICAL STUDY TO EVIDENCE THE ROLE OF THE POLYMER NATURE AND THE NANO…

2011

Interazioni tra nanotubi e molecole organiche

Nell'ampio scenario dei nanomateriali, i sistemi nanotubolari godono di un consolidato e crescente interesse sia nell'ambito scientifico che industriale. Fra la miriade di sistemi tubolari, i più utilizzati sono i nanotubi a base di carbonio e carbon nanohorns e più recentemente, vista l'elevata biocompatibilità e il loro basso costo, nanotubi inorganici quali i nanotubi di allosite. la funzionalizzazione di questi materiali con diverse tipologie di molecole organiche, ha permesso la sintesi di materiali che potrebbero o hanno trovato applicazione come filler polimerici, come supporti eterogenei in catalisi e nel campo del drug carrier e delivery. Inoltre, nel caso di nanotubi di allosite, …

Pb-PbOHCl Composite Nanowires Synthesized by Galvanic Deposition in Template

2019

In this paper, we report a detailed study on the synthesis of composite nanowires of Pb-PbOHCl via galvanic deposition into the pores of a membrane acting as a template. PbOHCl deposition quantitatively occurs as the solution pH exceeds the value of about 4.12. Simultaneously, owing to the galvanic coupling, electro-deposition of lead occurs, so composite nanowires were formed. The role of different parameters controlling the kinetic evolution of the process, such as oxygen bubbling, solution pH, surface area and type of sacrificial anode were investigated one at a time. The results suggest that every modification accelerating the alkalization of the solution inside the template pores favor…

Kompozyty polimerowe z napełniaczem roślinnym

2008

EVOLUZIONE DELLA LAGUNA DI TONNARELLA (MAZARA DEL VALLO, TRAPANI) E SUO ATTUALE VALORE ORNITOLOGICO

2016

Temporal changing of Tonnarella lagoon (Mazara del Vallo, Trapani) and its current ornithological value. Aims of this work were to highlight the importance of a small and artificial recently formed wetland area, that presents different interesting ornithological peculiarities. The Tonnarella lagoon is a breeding site of Little Tern Sternula albifrons and Kentish Plover Charadrius alexandrinus, both classified as “endangered” species in 2011 by the Red List of breeding birds in Italy; the site is considered of “national importance“ for Kentish Plover and “recorded site“ for the Sandwich Tern Sterna sandvicensis, due to the consistency of its wintering populations. Besides, the ornithological…