2,531 research outputs found

    Application of novel techniques for interferogram analysis to laser-plasma femtosecond probing

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    Recently, two novel techniques for the extraction of the phase-shift map (Tomassini {\it et.~al.}, Applied Optics {\bf 40} 35 (2001)) and the electronic density map estimation (Tomassini P. and Giulietti A., Optics Communication {\bf 199}, pp 143-148 (2001)) have been proposed. In this paper we apply both methods to a sample laser-plasma interferogram obtained with femtoseconds probe pulse, in an experimental setup devoted to laser particle acceleration studies.Comment: Submitted to Laser and Particle Beam

    Polyether from a biobased Janus molecule as surfactant for carbon nanotubes

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    A new polyether (PE) was prepared from a biobased Janus molecule, 2-(2,5-dimethyl-1H-pyrrol-1-yl)-1,3- propanediol (serinol pyrrole, SP). SP was synthesized with very high yield (about 96%) and high atom efficiency (about 80%) by reacting a biosourced molecule, such as serinol, with 2,5-hexanedione in the absence of solvent or catalyst. The reaction of SP with 1,6-dibromohexane led to PE oligomers, that were used as surfactants for multiwalled carbon nanotubes (MWCNT), in ecofriendly polar solvents such as acetone and ethyl acetate. The synergic interaction of aromatic rings and oxyalkylene sequences with the carbon allotrope led to dramatic improvement of surfactant efficiency: only 24% of SP based PE was extracted with ethyl acetate from the adduct with MWCNT, versus 98% of a typical pluronic surfactant. Suspensions of MWCNT-PE adducts in ethyl acetate were stable for months. High resolution transmission electron microscopy revealed a film of oligomers tightly adhered to MWCNT surface

    The laser-matter interaction meets the high energy physics: Laser-plasma accelerators and bright X/gamma-ray sources

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    Laser matter interaction in the regime of super-intense and ultra-short laser pulses is discovering common interests and goals for plasma and elementary particles physics. Among them, the electron laser wakefield acceleration and the X/Îł tunable sources, based on the Thomson scattering (TS) of optical photons on accelerated electrons, represent the most challenging applications. The activity of the Intense Laser Irradiation Laboratory in this field will be presented

    A valid academic path to promote respiratory physiotherapy

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    A one- year post- graduate Master in Physiotherapy and Pulmonary Rehabilitation has been offered within the University of Milan Medical School in collaboration with Associaz ione Italiana Riabilitatori dell\u2019Insufficienz a Respiratoria (ARIR). The aim is to cover a gap in Italian Physiotherapy academic curricula offering a course with theoretical and practical teaching that make students capable of using different techniques and procedures in respiratory physiotherapy. After the recognition by the International Education Recognition System (IERS), ARIR wanted to investigate if and how this course has affected students'attitude and their profession. METHODS A structured questionnaire made up of 15 multiple- choices items (8 on perceived quality of education and 7 on professional change) was sent by email to all physiotherapists who graduated in the previous four editions of the Master. One month was given for completion. Age, gender, year of degree and year of Master where considered as background variables. RESULTS We had a 78% response rate with 57 out of 73 physiotherapists sending the questionnaire back. Mean age was 37 years (23- 60) and women were the majority (78%). Forty- two students (74%) worked in the respiratory field at the time of application but only 15 (36%) dealt with respiratory patients only. Expectations were completely met at the end of Master for 71% of physiotherapists. 96% reported greater professional and clinical skills after the master with a 67% saying working team relationship has improved. 28% improved their job position thanks to the master degree and physiotherapy working in the respiratory field increased by 22%. CONCLUSIONS This course seems to meet students expectations and offer a solid knowledge to better work within the field of respiratory physiotherapy. It is also a way to promote the profession of respiratory physiotherapy in Italy

    Dynamics of charge-displacement channeling in intense laser-plasma interactions

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    The dynamics of transient electric fields generated by the interaction of high intensity laser pulses with underdense plasmas has been studied experimentally with the proton projection imaging technique. The formation of a charged channel, the propagation of its front edge and the late electric field evolution have been characterised with high temporal and spatial resolution. Particle-in-cell simulations and an electrostatic, ponderomotive model reproduce the experimental features and trace them back to the ponderomotive expulsion of electrons and the subsequent ion acceleration.Comment: 5 figures, accepted for publication in New Journal of Physic

    An original deconvolution approach for oil production allocation based on geochemical fingerprinting

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    We tackle oil commingling scenarios and develop an original deconvolution approach for geochemical production allocation. This yields robust assessment of the proportions of oils forming a mixture originating from commingling oils associated with diverse reservoirs or, wells. Our study starts from considering that production allocation performed by means of geochemical fingerprinting is relevant in the context of modern and sustainable use of georesources, with the added benefit of favoring shared facilities and production equipment. A geochemical production allocation workflow is typically structured according to two steps: (i) determination of the chromatograms associated with the mixture (and eventually with each of the End Members, EMs, constituting the fluids in the mixture), and (ii) the use of a deconvolution algorithm to estimate the mass fraction of each EM. Concerning the latter step, we introduce an original approach and the ensuing deconvolution algorithm (hereafter termed PGM) that does not require additional laboratory efforts in comparison with traditional approaches. We also present extensions of widely used deconvolution algorithms, which we frame in a (stochastic) Monte Carlo context to improve their robustness and reliability. The new PGM approach is assessed jointly with a suite of typically used approaches and algorithms against new laboratory-based commingling scenarios. The latter are based on the design and introduction of a novel and low-cost experimental method. The results of the study (i) constitute a unique and rigorous comparison of the traditionally employed production allocation deconvolution algorithms, (ii) document the critical importance of the number of features of the chromatograms used during a quantitative deconvolution, and (iii) suggest that our new PGM approach is very robust and accurate compared to existing approaches

    Ray-tracing simulations of a bent crystal X-ray optics for imaging using laser-plasma X-ray sources

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    Ray-tracing simulations of an optical X-ray system based on a spherically bent crystal operating in Bragg configuration for monochromatic projection imaging of thin samples are presented, obtained using a code developed for that purpose. The code is particularly suited for characterizing experimental arrangements routinely used with laser-produced plasma X-ray sources. In particular, the spatial resolution of the imaging system was investigated and a careful study of the complex pattern of the X-ray backlighting beam was performed

    Line spectroscopy with spatial resolution of laser-plasma X-ray emission

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    High dynamic range, space-resolved X-ray spectra of an aluminum laser–plasma in the 5.5–8 Å range were obtained using a TlAP crystal and a cooled CCD camera as a detector. This technique was used to investigate the emission region in the longitudinal direction over a distance of approximately 350 μm from the solid target surface. These data show that the electron density profile varies by two orders of magnitude with the temperature ranging from about 180 eV in the overdense region to about 650 eV in the underdense region. Accordingly, different equilibria take place across the explored region which can be identified with this experimental technique. Detailed studies on highly ionized atomic species in different plasma conditions can therefore be performed simultaneously under controlled conditions
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