Search results for "Microwave"

Imaging of Located Buried Defects in Metal Samples by an Scanning Microwave Microscopy

2011

Abstract A non-destructive method is proposed to detect the located buried defects using scanning microwave microscopy. Based on the “skin effect”, our recent developments authorize 3D tomography with nanometric resolution. This technique associates the electromagnetic microwave measurement using a Vector Network Analyzer (VNA) with the nanometer-resolution positioning capabilities of an Atomic Force Microscope. At each used frequency, an incident electromagnetic wave is send to the sample and the reflected wave gives information on a specific depth layer in the material. With a large bandwidth of frequencies, a 3D tomography is allowed inside the material. With characteristic tools of nano…

Microwave effects on germination and growth of radish (Raphanus sativus L.) seedlings

2002

Germination of radish seeds was delayed and reduced by low-power microwave exposure at 10.5 and 12.5 GHz. Irradiation decreased also hypocotyl growth rate. These effects were increased by rising of the microwave power and by the vertically polarised electromagnetic field. When the irradiation was suspended the seedling growth recovered.

LIQUIDI IONICI E FULLERENI: PIATTAFORME PER NUOVI MATERIALI

The synthesis of innovative catalysts based on different carbon nanoforms (CNFs), namely fullerene C60 and carbon nanotubes (CNTs), and their application in Suzuki and Heck C-C coupling reactions, constitutes the common thread of the first part (Chapter 1 and 2) of this thesis. C60 and CNTs were functionalized with ionic liquids (ILs) and poly-amidoamine (PAMAM) dendrimers, respectively, and used as supports for palladium nanoparticles (PdNPs). Moreover, additional supported catalytic systems based on one of the synthesized C60-IL hybrids were prepared and successfully employed in the title coupling reactions. The final part (Chapter 3) of the thesis deals on the microwave-mediated synthesi…

Inulin derivatives obtained via enhanced microwave synthesis as potential drug delivery system.

2013

Microwave response of coaxial cavities made of bulk MgB2

2012

A LAB-SCALE MICROWAVE SYSTEM FOR EXPERIMENTS OF HIGH TEMPERATURE WASTE PYROLYSIS

2016

The reactor designed and assembled at Università degli Studi di Palermo - presented here - was conceived to explore high unit power input, high temperature reductive processes. Its main field of use therefore is likely to be the destruction of liquid waste fed as an aerosol; or of VOCs; or of granular waste making a fluidized bed. If required, a 3 - phase system including a solid catalyst could also be set up. These waste should be free of low - melting or boiling metals. Incidentally, a literature review shows that the compounds taken as benchmark in thermal VOC destruction are trichloroethylene, benzene and toluene. At lower unit power rates this MW - based system lends itself also to rec…

STERILIZZAZIONE CON MICROONDE DI RIFIUTI SANITARI: DETERMINAZIONE DIRETTA DELL’EFFICACIA DEL PROCESSO

2018

In the sterilization of those Health Care Waste that are marked as possibly infectious, microwaves (MW) have long been proposed as an alternative means to steam. The effectiveness of the operation is assessed determining the fraction that has survived to the sterilizing agent of a known starting population of micro-organisms. Customarily, this population is introduced into the waste mass in the form of one or more sealed vials. These make up an artificial environment which is completely under control; but onto it the sterilizing agent could a priori behave with higher or lower effectiveness, compared with the loose mass which is directly exposed to it. As far as the traditional steam steril…

Propagation Channels for mmWave Vehicular Communications : State-of-the-art and Future Research Directions

2018

Vehicular communications essentially support automotive applications for safety and infotainment. For this reason, industry leaders envision an enhanced role for vehicular communications in the fifth generation of mobile communications technology. Over the years, the number of vehicle- mounted sensors has increased steadily, which potentially leads to more volume of critical data communications in a short time. Also, emerging applications such as remote/autonomous driving and infotainment such as high-definition movie streaming require data-rates on the order of multiple Gb/s. Such high data rates require a large system bandwidth, but very limited bandwidth is available in the sub-6 GHz cel…

Probing the radio emission from air showers with polarization measurements

2014

The emission of radio waves from air showers has been attributed to the so-called geomagnetic emission process. At frequencies around 50 MHz this process leads to coherent radiation which can be observed with rather simple setups. The direction of the electric field induced by this emission process depends only on the local magnetic field vector and on the incoming direction of the air shower. We report on measurements of the electric field vector where, in addition to this geomagnetic component, another component has been observed which cannot be described by the geomagnetic emission process. The data provide strong evidence that the other electric field component is polarized radially wit…

On-line tools for microscopic and macroscopic monitoring of microwave processing

2007

International audience; Direct monitoring of temperature, chemistry and microstructure is required to understand microwave heating in more detail, in order to fully exploit the unique features this non-equilibrium processing method can offer. In this paper, we show first that microwave radiometry can be used to follow volumetrically the thermal trajectory of microwave-heated aluminium powder. In-situ Raman spectroscopy is then shown to evidence thermal gradients between diamond and silicon grains in a binary powder mixture. Finally, perspectives and preliminary results of microstructural analysis obtained from X-ray microtomography are presented.