Atomic force microscopy techniques for nanomechanical characterization : a polymer case study

Atomic force microscopy (AFM) is a versatile tool to perform mechanical characterization of surface samples at the nanoscale. In this work, we review two of such methods, namely contact resonance AFM (CR-AFM) and torsional harmonics AFM (TH-AFM). First, such techniques are illustrated and their applicability on materials with elastic moduli in different ranges are discussed, together with their main advantages and limitations. Then, a case study is presented in which we report the mechanical characterization using both CR-AFM and TH-AFM of polyaniline and polyaniniline doped with nanodiamond particles tablets prepared by a pressing process. We determined the indentation modulus values of their surfaces, which were found in fairly good agreement, thus demonstrating the accuracy of the techniques. Finally, the determined surface elastic moduli have been compared with the bulk ones measured through standard indentation testing. INTRODUCTION In the field of nanotechnology, the development of innovative and nondestructive characterization techniques plays a crucial role. Indeed, the characterization of nanostructured hybrid materials (e.g., thin films and nanocomposites) and devices requires the capability of acquiring maps of the local mechanical properties at the nanoscale. Nanoindentation is the most common method for determining the mechanical properties of thin films. However, its applicability is strictly limited by the thickness of the sample. Furthermore, its poor spatial resolution does not allow the reconstruction of an accurate distribution of the sample surface mechanical properties. For this reason, alternative methods, based on atomic force microscopy (AFM), have been developed. By exploiting the high resolution of the AFM, maps of the surface mechanical properties (i.e., indentation modulus) can be achieved. Among these techniques, AFM nanoindentation1 is the simplest method used to evaluate the local mechanical properties o

Scientific basis of nanotechnology, implications for the food sector and future trends

Nanotechnologies are opening up new horizons in almost all scientific and technological fields. Among these, applications of nanotechnologies are expected to bring large benefits and add value to the food and food-related industries through the current regulatory framework whole food chain, from production to processing, safety, packaging, transportation, storage and delivery. Nanotechnology consists in the realization and manipulation of nano-sized matter, the unique properties of which with respect to their bulk counterparts are illustrated and discussed. Then, the main tools and techniques routinely used in nanotechnology for the nanoscale characterization of food matrices as well as for the analytical determination of nanomaterials in food samples are reviewed. Finally, safety and risk assessment issues are discussed and an overview of applications of nanotechnology to the food sector is provided along with a description of th

Study of MDT calibration constants using H8 testbeam data of year 2004

In year 2004 Atlas performed a long campaign of test beam data taking at the H8 Cern beam. Two sectors of the barrel and endcap regions of the Muon Spectrometer were exposed to the beam and large amount of data were collected in well defined and controlled operating conditions. This allowed a careful study on MDT drift properties. A better understanding of the calibration constants, of their definition and determination and of the criteria for their acceptance has been obtained. Systematic effects and time stability of the constants have also been studied

CONFRONTO DEI PARAMETRI GEOTECNICI E GEOFISICI PRE E POST BLAST TEST PRESSO IL SITO SPERIMENTALE DI MIRABELLO (FE)

L'articolo presenta alcuni risultati preliminari derivanti dal primo esperimento di liquefazione indotta tramite blast test realizzato in Italia, presso Mirabello (FE), comune fortemente colpito da fenomeni di liquefazione durante la sequenza sismica verificatasi in Emilia-Romagna nel 2012. In particolare diverse indagini in sito con tecniche invasive e non invasive sono state eseguite prima e dopo le detonazioni per confrontare la variazione dei parametri geotecnici e geofisici nel tempo

Measurement of the neutron detection efficiency of a 80% absorber - 20% scintillating fibers calorimeter

The neutron detection efficiency of a sampling calorimeter made of 1 mm diameter scintillating fibers embedded in a lead/bismuth structure has been measured at the neutron beam of the The Svedberg Laboratory at Uppsala. A significant enhancement of the detection efficiency with respect to a bulk organic scintillator detector with the same thickness is observed.Comment: 10 pages, 7 figure

Kaon physics with the KLOE detector

In this paper we discuss the recent finalized analyses by the KLOE experiment at DA$\Phi$NE: the CPT and Lorentz invariance test with entangled $K^0 \bar{K}^0$ pairs, and the precision measurement of the branching fraction of the decay ${ K^+} \rightarrow \pi^+\pi^-\pi^+(\gamma)$. We also present the status of an ongoing analysis aiming to precisely measure the $K^{\pm}$ mass

Precision measurement of the η→π+π−π0\eta\to\pi^+\pi^-\pi^0 Dalitz plot distribution with the KLOE detector

Using $1.6$ fb$^{-1}$ of $e^+ e^-\to\phi\to\eta\gamma$ data collected with the KLOE detector at DA$\Phi$NE, the Dalitz plot distribution for the $\eta \to \pi^+ \pi^- \pi^0$ decay is studied with the world's largest sample of $\sim 4.7 \cdot 10^6$ events. The Dalitz plot density is parametrized as a polynomial expansion up to cubic terms in the normalized dimensionless variables $X$ and $Y$. The experiment is sensitive to all charge conjugation conserving terms of the expansion, including a $gX^2Y$ term. The statistical uncertainty of all parameters is improved by a factor two with respect to earlier measurements.Comment: 11 pages, 9 figures, supplement: an ascii tabl

A global fit to determine the pseudoscalar mixing angle and the gluonium content of the eta' meson

We update the values of the eta-eta' mixing angle and of the eta' gluonium content by fitting our measurement R_phi = BR(phi to eta' gamma)/ BR(phi to eta gamma) together with several vector meson radiative decays to pseudoscalars (V to P gamma), pseudoscalar mesons radiative decays to vectors (P to V gamma) and the eta' to gamma gamma, pi^0 to gamma gamma widths. From the fit we extract a gluonium fraction of Z^2_G = 0.12 +- 0.04, the pseudoscalar mixing angle psi_P = (40.4 +- 0.6) degree and the phi-omega mixing angle psi_V = (3.32 +- 0.09) degree. Z^2_G and psi_P are fairly consistent with those previously published. We also evaluate the impact on the eta' gluonium content determination of future experimental improvements of the eta' branching ratios and decay width.Comment: 13 pages, 7 figures to submit to JHE