1,955 research outputs found

    Laboratory Experiments on Long Waves Interacting with Rigid Vertical Cylinders

    Get PDF
    The impact of waves caused by storm surges or floods could lead to significant damage to marine and fluvial structures. Hydraulic forces add significant hydrodynamic loads on bridges built in coastal and fluvial environments; therefore, the effect of the wave impact on bridge substructures must be properly considered for the safe and cost-effective design of the piers. The use of laboratory-scale models is a direct approach to investigate the effects of long waves on simple structures, mimicking bridge piers. The present study describes a laboratory-scale model, where the propagation of two different long waves in a flume, in the presence of two rigid cylinders, was investigated. The velocity measurements were acquired by the Particle Image Velocimetry (PIV) technique, providing instantaneous flow velocity vectors on 2D planes. For each experimental condition, the instantaneous velocity field close to the cylinders was analysed, in order i) to depict how it changes during the wave transit, and thus how the drag force acting on the cylinders could change, ii) to detect the spatial distributions of vorticity downstream. Some first interesting results have been obtained, showing a quite uniform distribution of the longitudinal velocity along the depth of the vertical plane upstream of the cylinders, with increasing values during the wave transit. No interactions in the central part of the flow downstream of the two cylinders was observed in the horizontal plane which are spaced approximately ten times their diameter. Finally, the vorticity has also been studied, displaying a phase-varying behaviour, which appears to lose symmetry during wave transit

    Experimental Setup and Measuring System to Study SolitaryWave Interaction with Rigid Emergent Vegetation

    Get PDF
    The aim of this study is to present a peculiar experimental setup, designed to investigate the interaction between solitary waves and rigid emergent vegetation. Flow rate changes due to the opening and closing of a software-controlled electro-valve generate a solitary wave. The complexity of the problem required the combined use of different measurement systems of water level and velocity. Preliminary results of the experimental investigation, which allow us to point out the effect of the vegetation on the propagation of a solitary wave and the effectiveness of the measuring system, are also presented. In particular, water level and velocity field changes due to the interaction of the wave with rigid vegetation are investigated in detail

    Application of an EGR system in a direct injection diesel engine to reduce NOx emissions

    Get PDF
    This work presents the application of an exhaust gas recirculation (EGR) system in a direct injection diesel engine operating with diesel oil containing 7% biodiesel (B7). EGR rates of up to 10% were applied with the primary aim to reduce oxides of nitrogen (NOx) emissions. The experiments were conducted in a 44 kW diesel power generator to evaluate engine performance and emissions for different load settings. The use of EGR caused a peak pressure reduction during the combustion process and a decrease in thermal efficiency, mainly at high engine loads. A reduction of NOx emissions of up to 26% was achieved, though penalizing carbon monoxide (CO) and total hydrocarbons (THC) emissions

    Conceptual design of superferric magnets for PS2

    Get PDF
    We analyze feasibility and cost of a superferric magnet design for the PS2. Specifically, we provide the conceptual design of dipole and quadrupoles, including considerations on cryogenics and powering. The magnets have warm iron yoke, and cryostated superconducting coils embedded in the magnet, which reduces AC loss at cryogenic temperature. The superconductor has large Operating margin to endure beam loss and operating loads over a long period of time. Although conservative, and without any critical dependence on novel technology developments, this superconducting option appears to be attractive as a low-power alternative to the normal-conducting magnets that are the present baseline for the PS2 design. In addition it provides flexibility in the selection of flat-top duration at no additional cost. This study is the conclusion of the conceptual design work started within the scope of the CARE HHH-AMT activities, following inputs from the workshops ECOMAG and LUMI-06, and finally spurred by the recent discussions on the opportunity of an R&D for the PS2 magnets

    Conceptual Design of Superferric Magnets for PS2

    Get PDF
    We analyze feasibility and cost of a superferric magnet design for the PS2, the 50 GeV ring that should replace the PS in the CERN injector chain. Specifically, we provide the conceptual design of dipole and quadrupoles, including considerations on cryogenics and powering. The magnets have warm iron yoke, and cryostated superconducting coils embedded in the magnet, which reduces AC loss at cryogenic temperature. The superconductor has large operating margin to endure beam loss and operating loads over a long period of time. Although conservative, and without any critical dependence on novel technology developments, this superconducting option appears to be attractive as a low-power alternative to the normal-conducting magnets that are the present baseline for the PS2 design. In addition it provides flexibility in the selection of flat-top duration at no additional cost

    Genomic changes of chromosomes 8p23.1 and 1q21: Novel mutations in malignant mesothelioma

    Get PDF
    Introduction: Malignant mesothelioma is an aggressive malignancy of the thoracic cavity caused by prior asbestos exposure. In the peritoneum the mesothelioma is an extremely rare condition. In the present preliminary study, high-resolution array-comparative genomic hybridization (a-CGH) was performed to identify genetic imbalances in a series of malignant peritoneal mesothelioma cases. Materials and methods: Between 1990 and 2008, among the cases recorded in the Apulia Mesothelioma Register, we found 22 peritoneal mesothelioma cases. CGH-array was performed on samples from all patients. Results: The CGH-array analysis revealed multiple chromosomal imbalances. Interestingly, deletion at 8p23.1 was observed in 12 cases. Furthermore, another novel deletion at 1q21 was present in 11. Often, 1q21 and 8p23.1 losses were present in the same patient (7 cases). Losses of BAP1 and CDKN2A loci were not detected. Discussion: The region at 8p23.1 contains the beta-defensin gene cluster (DEF) and 1q21 contains ubiquitin conjugating enzyme E2 (UBE2Q1). We hypotesized that the loss of function of ubiquitination, as well as of the defensins, could play an important role in the initial development and subsequent progression of mesothelioma

    Fast cycled superconducting magnets for the upgrade of the LHC injector complex

    Get PDF
    An upgrade of the LHC injection chain, and especially the sequence of PS and SPS, up to an extraction energy of 1 TeV, is one of the steps considered to improve the performance of the whole LHC accelerator complex. The magnets for this upgrade require central magnetic field from 2 T (for a PS upgrade) to 4.5 T (for an SPS upgrade), and field ramp rate ranging from 1.5 to 2.5 T/s. In this paper we discuss under which conditions superconducting magnets are attractive in this range of operating field and field ramp-rate, and we list the outstanding issues to be adddressed by a dedicated R&D

    Turbulent jet through porous obstructions under Coriolis effect: an experimental investigation

    Get PDF
    The present study has the main purpose to experimentally investigate a turbulent momentum jet issued in a basin affected by rotation and in presence of porous obstructions. The experiments were carried out at the Coriolis Platform at LEGI Grenoble (FR). A large and unique set of velocity data was obtained by means of a Particle Image Velocimetry measurement technique while varying the rotation rate of the tank and the density of the canopy. The main differences in jet behavior in various flow configurations were assessed in terms of mean flow, turbulent kinetic energy and jet spreading. The jet trajectory was also detected. The results prove that obstructions with increasing density and increased rotation rates induce a more rapid abatement of both jet velocity and turbulent kinetic energy. The jet trajectories can be scaled by a characteristic length, which is found to be a function of the jet initial momentum, the rotation rate, and the drag exerted by the obstacles. An empirical expression for the latter is also proposed and validated

    Effect of Diet and Essential Oils on the Fatty Acid Composition, Oxidative Stability and Microbiological Profile of Marchigiana Burgers

    Get PDF
    The objective of this study is to evaluate the effects of including linseed (L) or linseed plus vitamin E (LE) in the diet of Marchigiana young bulls on the oxidative stability, color measurements, microbiological profile and fatty acid composition (FA) of burgers treated with and without a blend of essential oils (Rosmarinus officinalis and Origanum vulgare var. hirtum) (EOs). For this aim, the burgers were analysed for pH, thiobarbituric-acid-reactive substance (TBARS) content, Ferric Reducing/Antioxidant Power Assay (FRAP), vitamin E and colour measurements (L, a*, b) at 3, 6, 9, 12 days of storage: the TBARs were the highest in group L compared to C and LE after 12 days of storage (0.98, 0.73, and 0.63 mg MDA/kg, respectively). The TBARS content was also influenced by the use of EO compared to burgers not treated with EO (p < 0.05). The vitamin E content was influenced by the diet (p < 0.01), but not by the EO. The meat of the L group showed the lowest value of redness (a*) compared to C and LE (p < 0.01), while the use of EO did not affect colour parameters. The microbiological profile of the burgers showed a lower Pseudomonas count for L and LE at T0 (2.82 ± 0.30 and 2.30 ± 0.52 Log CFU/g, respectively) compared to C (3.90 ± 0.38 Log CFU/g), while the EO did not influence the microbiological profile. The FA composition was analysed at 0 and 12 days. The burgers from the LE group showed the highest value of polyunsaturated FA compared to the L and C groups (p < 0.05). Our findings suggest that the inclusion of vitamin E in a concentrate rich in polyunsaturated fatty acids is useful to limit intramuscular fat oxidation and to preserve the colour stability of burgers from young Marchigiana bulls enriched with healthy fatty acids. Moreover, linseed and vitamin E had a positive effect on microbial loads and growth dynamics, containing microbial development through time

    Salmonella enterica Control in Stick Carrots Through Incorporation of Coriander Seeds Essential Oil in Sustainable Washing Treatments

    Get PDF
    Chemical disinfectants represent one of the commonly used practice in minimally processed vegetables food-chain. However, the scarce safety and sustainability of these agents force food industry to move toward more sustainable “green washing solutions.” Among the latter, while the application of plant derivates for the control of several pathogens is already well-known, the potential anti-Salmonella activity of Coriandrum sativum seeds derivates is still unexplored and was therefore investigated in this study. In detail, Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) of different coriander seed derivates (i.e., essential oil, hydrosol, and ethanolic extract) were determined by broth dilution against six Salmonella enterica strains isolated from fresh and minimally processed fruits and vegetables. Only the essential oil (EO) was effective in vitro with strain-dependent results. In addition, when mixed in co-culture, the strains were more sensitive to the essential oil treatment. Chemical investigations allowed to define (s)-(+)-linalool as major compound in the essential oil, and to underline interesting phenolic content with correlated antioxidant capacity. A cocktail of three strains of different serovars was selected and employed for a preliminary in situ trial on stick carrots. The obtained results allowed to establish that the application of coriander seed EO at concentrations of 5 ÎŒL mL−1 was able to reduce and contain the growth of the Salmonella cocktail up to 24 h at 10°C. Good sensory evaluation results were obtained by applying this EO concentration as washing treatment, especially in terms of color parameter. Further studies should be undertaken to emphasize the upstream activity, improving the formulation or exploiting a combined effect with other sanitizers or treatments (e.g., physical treatments). The present study contributes to the knowledge on coriander derivates activity against Salmonella spp. and on the potential application as sustainable washing treatment in removing this pathogen from fresh cut carrots
    • 

    corecore