79 research outputs found

    Two autobiographies from Ludovica Ripa di Meana’s works

    Get PDF
    Nei romanzi e nei testi teatrali di Ludovica Ripa di Meana la dimensione autobiografica risulta quasi completamente assente. È rintracciabile, in forme originali nel libro-intervista al filologo Gianfranco Cortini e nel suo primo testo, Asma. Attraverso questi due testi emerge come il tema autobiografico sia uno strumento fondamentale alla ricerca della propria voce.In the novels and theatrical texts of Ludovica Ripa di Meana the autobiographical dimension is almost completely absent. It can be found in original forms in the book-interview with the philologist Gianfranco Cortini and in his first text, Asma. Through these two texts it emerges that the autobiographical theme is a fundamental tool in the search for one’s own voice

    modelling and energy comparison of system layouts for a hydraulic excavator

    Get PDF
    Abstract For decades the improvement of energy efficiency in mobile hydraulics has forced the research world to develop energy saving solutions and to redesign existing hydraulic circuits. This paper presents an overview about the state of the art of excavator valve systems based on open centre flow control (OFC) and a load sensing principle (LS). The purpose of this study is to compare different hydraulic systems on a middle size (9ton) excavator and to analyse the differences in term of energy saving and fuel consumption. Starting from a validate mathematical model of the considered hydraulic excavator whose functioning is in LS logic, many alternatives are proposed as flow on demand system, positive and negative flow control. Systems comparison has been done on typical excavator working cycles as trench digging and levelling referring to the JCMAS standard. An optimization tool, based on genetic algorithm, has been exploited for the definition of the optimal spool areas to reduce the pressure losses and by-pass flow rate maintaining identical controllability and performance

    dynamic modelling of the swash plate of a hydraulic axial piston pump for condition monitoring applications

    Get PDF
    Abstract In the last years Prognostic and Health Management (PHM) has become one of the challenging topic in the engineering field. In particular, model-based approach for diagnostic relies on the development of a mathematical model of the system representing its flawless status. Once the model has been developed and carefully calibrated on experimental data referred to flawless pump condition the comparison between the model output and the real system output leads to the residual analysis, which gives a diagnosis of the component health. This paper presents the mathematical model of a hydraulic axial piston pump developed in order to replicate the dynamic behavior of the swash plate for PHM applications. The model has been developed on the basis of simplified hypotheses, a friction model between swash plate and bearings has been introduced. A detailed experimental activity was carried out to calibrate and validate the model with step tests and sweep tests. The comparison between numerical and experimental results shows a satisfying agreement and highlights the model capability to reproduce the swash plate dynamics. Future works will include tests with the pump in faulty conditions to evaluate the pump health state through the residual analysis of the swash plate position

    Colonization of transplanted Posidonia oceanica. Understanding the spatial dynamics through high-spatial resolution underwater photomosaics

    Get PDF
    Following the restoration of a Posidonia oceanica meadow impacted by theConcordia shipwreck, we investigated the spatial dynamic of the most important andprotected Mediterranean endemic seagrass over a two-year period applying three spatialmetrics: number of patches, mean patch size and total cover. By means of underwaterphotomosaics, we noticed a diminution in the number of patches in favour of the mean sizeand total cover. The outcomes showed that, under suitable environmental conditions,P. oceanica colonizes rapidly the dead matte substrate. This study underlines the importanceof considering the spatial dynamic of transplanted seagrasses in monitoring programmes andgives new insights on the progression rate of transplanted P. oceanica

    Energy saving solutions for a hydraulic excavator

    Get PDF
    Abstract Nowadays the improvement of energy efficiency and the reduction of pollutant emissions are the major challenges that the mobile machinery manufacturers have to face with. With rising fuel prices and increasingly stringent regulations, the development of energy saving solutions and efficient hydraulic system have become a priority for researchers and OEM's. One of the most effective approach is the machine hybridization but other solutions can be adopted. This paper proposes with the aid of mathematical tools energy saving solutions for an excavator equipped with a load sensing hydraulic system. A comprehensive energy analysis was conducted through the excavator model to highlight the energy dissipations along the system. Different solutions to reduce losses and improve fuel saving including energy recovery from boom and arm and the introduction of a second pump in the flow generation unit were identified and investigated in detail. Finally, combining the proposed solutions, a new hydraulic hybrid excavator concept was obtained with a 15% of fuel saving

    Double trouble. Synergy between habitat loss and the spread of the alien species Caulerpa cylindracea (Sonder) in three Mediterranean habitats

    Get PDF
    The role of habitat degradation on the spread of the alien green alga Caulerpa cylindracea is reported here by comparing observations achieved through a multi-year assessment on three Mediterraneans habitats, namely Posidonia oceanica meadows, Phyllophora crispa turf, and coralligenous reefs. Due to the peculiarity of the study site, both natural-reference and impacted conditions were investigated. C. cylindracea occurred in all the studied habitats under impacted conditions. High susceptibility to the invasion characterized impacted P. oceanica, where Caulerpa cover reached 70.0% in summer months. C. cylindracea cover did not differ significantly among conditions in P. crispa turf, where values never exceeded 5.0%. Conversely, the invasive green algae was low in abundance and patchily distributed in coralligenous reefs. Our results confirmed that habitat loss enhances the spread of C. cylindracea, although with different magnitudes among habitats. Dead matte areas of P. oceanica represented the most vulnerable habitat among those analyzed, whereas coralligenous reefs were less susceptible to the invasion under both the studied conditions

    Human The Distal Perforators Of Posterior Tibial Artery. A Study For The Correct Planning Of Medial Lower Leg Flaps

    Get PDF
     The adipofascial flap, introduced by Lin in 1994 (1), has many advantages compared to fasciocutaneous or free flaps for lower limb reconstruction. Its dissection is relatively easy and fast with low donor site morbidity and it doesn’t alter the shape of the leg. The aim of this dissection study is to evaluate the anatomic localization of the most distal perforator of the posterior tibial vessels to provide an anatomical rationale for the safe harvesting of distally based medial adipofascial flaps of the leg. Thirty lower limbs from 15 cadavers were used for this study. In all the limbs, the femoral artery was cannulated. Different techniques of injection were employed. 26 specimens were injected with latex to fill the entire vascular network and ease dissection. 3 specimens were injected with a mixture of barium sulphate and gelatin and underwent a CT scan. CT scan dataset were used to make 3D reconstruction. They underwent anatomical dissection after the scan. 1 Specimen was injected with red epoxy resin mixed with barium sulphate (2). This technique is aimed to perform comparative anatomical vascular studies between CT three-dimensional reconstructions and traditional dissection techniques. A distal perforator was found in all specimens; the mean caliber was 0.77 mm. In all cases, the perforator artery passed in the septum between flexor hallucis longus m. and flexor digitorum longus m. and was accompanied by two veins. In our series, the distance between the lowest perforator and the medial malleolus ranged from 3.5 to 8.2 cm. The median was 6.75 cm, the 5th percentile 4 cm and the 95th percentile 8.1 cm. The mean distance of the perforator from the medial tibial border was 1.23 cm. The mean ratio between the distance of perforator from the medial malleolus and the total leg length was 21%. Compared to all previous researches (3), our study has found more distal perforators from posterior tibial perforator artery. This fact may have important clinical consequences because the anteromedial adipofascial flap would cover more distal soft tissue defects. Moreover, our data suggest some safety parameters to make the rising of a medial adipofascial leg flap safer in surgical practice

    Novel genetic association of TNF-α-238 and PDCD1-7209 polymorphisms with long-term non-progressive HIV-1 infection.

    Get PDF
    About 2-5% of HIV-1-infected subjects, defined as long-term non-progressors (LTNPs), remain immunologically stable for a long time without treatment. The factors governing this condition are known only in part, and include genetic factors. Thus, we studied 20 polymorphisms of 15 genes encoding proinflammatory and immunoregulatory cytokines, chemokines and their receptors, genes involved in apoptosis, and the gene HCP5. METHODS: We analyzed 47 Caucasian LTNPs infected for >9 years, compared with 131 HIV-1-infected Caucasian patients defined as 'usual progressors'. The genotypes were determined by methods based upon PCR, and the statistical analysis was performed by univariate logistic regression. RESULTS: The well-known CCR5Δ32 del32 allele, the cell death-related TNF-α-238 A and PDCD1-7209 T alleles, and HCP5 rs2395029 G, a non-coding protein associated with the HLA-B*5701, were found positively associated with the LTNP condition. No association was observed for other single nucleotide polymorphisms (SDF-1-801, IL-10-592, MCP-1-2518, CX3CR1 V249I, CCR2V64I, RANTES-403, IL-2-330, IL-1β-511, IL-4-590, FASL IVS3nt-169, FAS-670, FAS-1377, FASL IVS2nt-124, PDCD1-7146, MMP-7-181, and MMP7-153). CONCLUSIONS: The novel genetic associations between allelic variants of genes TNF-α-238 and PDCD1-7209 with the LTNP condition underline the importance of host genetic factors in the progression of HIV-1 infection and in immunological preservation
    • …
    corecore