710 research outputs found

    MULTI‐PHYSICAL MODELLING AND PROTOTYPING OF AN ENERGY HARVESTING SYSTEM INTEGRATED IN A RAILWAY PNEUMATIC SUSPENSION

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    The aim of this PhD thesis is the investigation of an energy harvesting system to be integrated in a railway pneumatic spring to recovery otherwise wasted energy source from suspension vibration. Exploiting the piezoelectric effect to convert the mechanical energy into an electrical one, the final scope consists on the use of this system to power supply one or more sensors that can give useful information for the monitoring and the diagnostics of vehicle or its subsystems. Starting from the analysis of the energy sources, a multi‐physical approach to the study of an energy harvesting system is proposed to take into account all physics involved in the phenomenon, to make the most of the otherwise wasted energy and to develop a suitable and affordable tool for the design. The project of the energy harvesting device embedded in a railway pneumatic spring has been carried out by means of using a finite element technique and multi‐physics modelling activity. The possibility to combine two energy extraction processes was investigated with the purpose of making the most of the characteristics of the system and maximize the energy recovering. Exploiting commercial piezoelectric transducers, an experimental activity was conducted in two steps. A first mock‐up was built and tested on a shaker to develop the device and to tune the numerical model against experimental evidence. In the second step a fullscale prototype of an air spring for metro application with the EH system was realized. In order to test the full‐scale component, the design of a new test bench was carried out. Finally, the Air spring integrated with the EH device was tested and models validated

    A comparison between TOPSIS and SAW methods

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    The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and Simple Additive Weighting (SAW) are among the most employed approaches for aggregating performances in Multi-Criteria Decision-Making (MCDM). TOPSIS and SAW are two MCDM methods based on the value function approach and are often used in combination with other MCDM methods in order to produce rankings of alternatives. In this paper, first, we analyse some common features of these two MCDM methods with aspecific reference to the additive properties of the value function and to the sensitivity of the value function to trade-off weights. Based on such methodological insights, an experimental comparison of the results provided by these two aggregation methods across a computational test is performed. Specifically, similarities in rankings of alternatives produced by TOPSIS and SAW are evaluated under three different Minkowski distances (namely, the Euclidean, Manhattan and Tchebichev ones). Similarities are measured trough a set of statistical indices. Results show that TOPSIS, when used in combination with a Manhattan distance, produces rankings which are extremely similar to the ones resulting from SAW. Similarities are also Experimental results confirm that rankings produced by TOPSIS methods are closer to SAW ones when similar formal properties are satisfied

    Not only P-glycoprotein: amplification of the ABCB1-containing chromosome region 7q21 confers multidrug resistance upon cancer cells by coordinated overexpression of an assortment of resistance-related proteins

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    The development of drug resistance continues to be a dominant hindrance toward curative cancer treatment. Overexpression of a wide-spectrum of ATP-dependent efflux pumps, and in particular of ABCB1 (P-glycoprotein or MDR1) is a well-known resistance mechanism for a plethora of cancer chemotherapeutics including for example taxenes, anthracyclines, Vinca alkaloids, and epipodopyllotoxins, demonstrated by a large array of published papers, both in tumor cell lines and in a variety of tumors, including various solid tumors and hematological malignancies. Upon repeated or even single dose treatment of cultured tumor cells or tumors in vivo with anti-tumor agents such as paclitaxel and doxorubicin, increased ABCB1 copy number has been demonstrated, resulting from chromosomal amplification events at 7q11.2-21 locus, leading to marked P-glycoprotein overexpression, and multidrug resistance (MDR). Clearly however, additional mechanisms such as single nucleotide polymorphisms (SNPs) and epigenetic modifications have shown a role in the overexpression of ABCB1 and of other MDR efflux pumps. However, notwithstanding the design of 4 generations of ABCB1 inhibitors and the wealth of information on the biochemistry and substrate specificity of ABC transporters, translation of this vast knowledge from the bench to the bedside has proven to be unexpectedly difficult. Many studies show that upon repeated treatment schedules of cell cultures or tumors with taxenes and anthracyclines as well as other chemotherapeutic drugs, amplification, and/or overexpression of a series of genes genomically surrounding the ABCB1 locus, is observed. Consequently, altered levels of other proteins may contribute to the establishment of the MDR phenotype, and lead to poor clinical outcome. Thus, the genes contained in this ABCB1 amplicon including ABCB4, SRI, DBF4, TMEM243, and RUNDC3B are overexpressed in many cancers, and especially in MDR tumors, while TP53TG1 and DMTF1 are bona fide tumor suppressors. This review describes the role of these genes in cancer and especially in the acquisition of MDR, elucidates possible connections in transcriptional regulation (co-amplification/repression) of genes belonging to the same ABCB1 amplicon region, and delineates their novel emerging contributions to tumor biology and possible strategies to overcome cancer MDR

    Fractional Calculus Approach to Reproduce Material Viscoelastic Behavior, including the Time–Temperature Superposition Phenomenon

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    The design of modern products and processes cannot prescind from the usage of viscoelastic materials that provide extreme design freedoms at relatively low cost. Correct and reliable modeling of these materials allows effective use that involves the design, maintenance, and monitoring phase and the possibility of reuse and recycling. Fractional models are becoming more and more popular in the reproduction of viscoelastic phenomena because of their capability to describe the behavior of such materials using a limited number of parameters with an acceptable accuracy over a vast range of excitation frequencies. A particularly reliable model parametrization procedure, using the poles-zeros formulation, allows researchers to considerably reduce the computational cost of the calibration process and avoid convergence issues typically occurring for rheological models. The aim of the presented work is to demonstrate that the poles-zeros identification methodology can be employed not only to identify the viscoelastic master curves but also the material parameters characterizing the time-temperature superposition phenomenon. The proposed technique, starting from the data concerning the isothermal experimental curves, makes use of the fractional derivative generalized model to reconstruct the master curves in the frequency domain and correctly identify the coefficients of the WLF function. To validate the methodology, three different viscoelastic materials have been employed, highlighting the potential of the material parameters' global identification. Furthermore, the paper points out a further possibility to employ only a limited number of the experimental curves to feed the identification methodology and predict the complete viscoelastic material behavior

    ÉvĂ©nement : LumiĂšres d’ailleurs. Rencontres de l’édition Ă©trangĂšre et de la traduction, Lyon 2014

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    OrganisĂ©es par les Ă©tudiants du Master 2 Pro TLEC de la FacultĂ© des langues de l’universitĂ© Lyon 2, ces rencontres se sont tenues les 23-24-25 janvier 2014 dans le cadre suggestif du MusĂ©e des Moulages de Lyon. La confĂ©rence inaugurale a Ă©tĂ© confiĂ©e Ă  Jean-Yves Masson qui a examinĂ© du point de vue historique, littĂ©raire, Ă©ditorial et disons, syndical, les aspects inhĂ©rents Ă  la traduction, une vĂ©ritable lectio magistralis. La premiĂšre journĂ©e Ă©tait axĂ©e sur diffĂ©rentes tables rondes privilĂ©gi..

    Ouvrage : La Cigarette et le Néant, Horace Engdahl

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    Il y a une page cĂ©lĂšbre de La coscienza di Zeno, oĂč Italo Svevo disserte sur son addiction Ă  la cigarette. Le propos « Puisque fumer me fait mal, je ne fumerai plus mais avant je veux le faire pour la derniĂšre fois », jamais observĂ©, est devenu paradigmatique de l’ennui et de l’angoisse existentiels. Écrivain et critique, membre de l’AcadĂ©mie suĂ©doise, Horace Engdahl ne cite jamais l’écrivain italien, mais en cite des dizaines d’autres, classiques et modernes, de son pays et d’Europe, dans un..

    ÉvĂ©nement : LumiĂšres d’ailleurs. Rencontres de l’édition Ă©trangĂšre et de la traduction, Lyon 2014

    Get PDF
    OrganisĂ©es par les Ă©tudiants du Master 2 Pro TLEC de la FacultĂ© des langues de l’universitĂ© Lyon 2, ces rencontres se sont tenues les 23-24-25 janvier 2014 dans le cadre suggestif du MusĂ©e des Moulages de Lyon. La confĂ©rence inaugurale a Ă©tĂ© confiĂ©e Ă  Jean-Yves Masson qui a examinĂ© du point de vue historique, littĂ©raire, Ă©ditorial et disons, syndical, les aspects inhĂ©rents Ă  la traduction, une vĂ©ritable lectio magistralis. La premiĂšre journĂ©e Ă©tait axĂ©e sur diffĂ©rentes tables rondes privilĂ©gi..

    Ouvrage : La Cigarette et le Néant, Horace Engdahl

    Get PDF
    Il y a une page cĂ©lĂšbre de La coscienza di Zeno, oĂč Italo Svevo disserte sur son addiction Ă  la cigarette. Le propos « Puisque fumer me fait mal, je ne fumerai plus mais avant je veux le faire pour la derniĂšre fois », jamais observĂ©, est devenu paradigmatique de l’ennui et de l’angoisse existentiels. Écrivain et critique, membre de l’AcadĂ©mie suĂ©doise, Horace Engdahl ne cite jamais l’écrivain italien, mais en cite des dizaines d’autres, classiques et modernes, de son pays et d’Europe, dans un..
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