A non-geodesic motion in the R^-1 theory of gravity tuned with observations

In the general picture of high order theories of gravity, recently, the R^-1 theory has been analyzed in two different frameworks. In this letter a third context is added, considering an explicit coupling between the R^-1 function of the Ricci scalar and the matter Lagrangian. The result is a non-geodesic motion of test particles which, in principle, could be connected with Dark Matter and Pioneer anomaly problems.Comment: Accepted for Modern Physics Letters

CFD-3D and 1D modeling of fuel cell powertrain for a hydrogen vehicle

As it is known the transport sector represents a major contributor to climate change. In particular, private transport contributes to the degradation of the air quality inside the cities or the residential areas. To address this issue, a progressive reduction of the use of fossil fuels as a primary energy source for these vehicles and the promotion of cleaner powertrain alternatives is in order. This study focuses on designing a fuel cell powertrain for a hydrogen-powered passenger car using numerical modeling. To this purpose, we initially modeled a base fuel cell and optimized its performance by using various materials for the bipolar plates and adjusting the platinum loading between the anode and cathode. Then, a preliminary design of the new powertrain has been proposed in order to achieve a nominal power of 100 kW and it has been tested on a WLTP 3b homologation cycle. Finally, we have been able to numerically estimate the behavior of the three main feeding line: hydrogen line, air line and cooling line. In conclusion, the obtained results demonstrate how numerical modelling can be successfully used in the design of complex systems such as those related to alternative energy. This work also provides a solid basis for the future development of increasingly efficient and environmentally friendly hydrogen vehicles

Influenza del Potyvirus latente del carciofo «Spinoso sardo» sulla produitività delle piante in pieno campo: 2. risultati relativi al secondo anno di impianto

In order to evaluate the influence of the artichoke latent Potyvirus (ALV) on plant productivity, a comparative field trial between virus-freed by meristem-tip culture and naturally Infected «Spinoso sardo» plants has been repeated for the second year in Sardinia. On the whole the results corroborate those of the first year: the latent infection doesn't affect the earliness and the number of heads per plant; whereas it negatively influences the weight, the diamater and the stem length of the heads

Reperimento del virus dell'«arricciamento maculato» il del carciofo (AMCV) in Sardegna

A virus disease of «Masedu» of artichoke has been observed, in a serious form, in southern Sardinia (Italy). Affected plants are stunted with leaves heavily mottled, crinkled and laciniated. On the basis of the herbaceous hosts reactions, physical properties «in vitro», spectrophotometry, electron microscopy and serology, the virus recovered from diseased plants is identified as an isolate of AMCV, belonging to «Tombusvirus» group, serologically undistinguishable from the italian type isolate

Il Risanamento degli agrumi dal viroide dell'Exocortite mediante il microinnesto

Nearly all old line citrus trees growing in Sardinia (Italy) are infected by citrus exocortis viroid (CEV). The technique of shoot-tip grafting has proved effective in recovering various citrus cultivars free of this viroid

Non-canonical WNT/PCP signalling in cancer: Fzd6 takes centre stage.

Frizzled receptors are the mediators of the wnt canonical and non-canonical pathways, which play fundamental roles in cell differentiation and organism development. A large body of work indicates that dysregulation of wnt signalling is a feature of oncogenic transformation, but most of the studies published so far focus on the assessment of the consequences of aberrations of the canonical pathway in human cancer. In this review, we discuss the emerging role of the wnt non-canonical pathway regulated by frizzled receptor 6 (Fzd6) in the pathogenesis of different types of human malignancies. The function played by Fzd6 in the physiology of normal and cancer cells has been highlighted in the view that an increased knowledge of the signalling pathways upstream and downstream of this receptor could ultimately result in the identification of new targets for cancer therapy

Removing black-hole singularities with nonlinear electrodynamics

We propose a way to remove black hole singularities by using a particular nonlinear electrodynamics Lagrangian that has been recently used in various astrophysics and cosmological frameworks. In particular, we adapt the cosmological analysis discussed in a previous work to the black hole physics. Such analysis will be improved by applying the Oppenheimer-Volkoff equation to the black hole case. At the end, fixed the radius of the star, the final density depends only on the introduced quintessential density term $\rho_{\gamma}$ and on the mass.Comment: In this last updated version we correct two typos which were present in Eqs. (21) and (22) in the version of this letter which has been published in Mod. Phys. Lett. A 25, 2423-2429 (2010). In the present version, both of Eqs. (21) and (22) are dimensionally and analytically correc

Three-Dimensional CFD Simulation of a Proton Exchange Membrane Electrolysis Cell

The energy shift towards carbon-free solutions is creating an ever-growing engineering interest in electrolytic cells, i.e., devices to produce hydrogen from water-splitting reactions. Among the available technologies, Proton Exchange Membrane (PEM) electrolysis is the most promising candidate for coping with the intermittency of renewable energy sources, thanks to the short transient period granted by the solid thin electrolyte. The well-known principle of PEM electrolysers is still unsupported by advanced engineering practices, such as the use of multidimensional simulations able to elucidate the interacting fluid dynamics, electrochemistry, and heat transport. A methodology for PEM electrolysis simulation is therefore needed. In this study, a model for the multidimensional simulation of PEM electrolysers is presented and validated against a recent literature case. The study analyses the impact of temperature and gas phase distribution on the cell performance, providing valuable insights into the understanding of the physical phenomena occurring inside the cell at the basis of the formation rate of hydrogen and oxygen. The simulations regard two temperature levels (333 K and 353 K) and the complete polarization curve is numerically predicted, allowing the analysis of the overpotentials break-up and the multi-phase flow in the PEM cell. An in-house developed model for macro-homogeneous catalyst layers is applied to PEM electrolysis, allowing independent analysis of overpotentials, investigation into their dependency on temperature and analysis of the cathodic gas–liquid stratification. The study validates a comprehensive multi-dimensional model for PEM electrolysis, relevantly proposing a methodology for the ever-growing urgency for engineering optimization of such devices

Sampling pollen beetle (Brassicogethes aeneus) pressure in oilseed rape: which method is best?

BACKGROUND: The pollen beetle (Brassicogethes aeneus) is the most abundant pests of oilseed rape in spring and potentially one of the most damaging. Adults feed on the pollen within closed flower buds and the damage leads to bud abscission, resulting in podless stalks and yield reduction. Several methods are currently used to monitor the pressure of this insect such as counting the numbers of adults on the plants, quantifying the number of buds damaged by the insect before flowering or counting the number of podless stalks before harvest. We conducted experiments to evaluate the robustness of these sampling methods and compared their results. We also describe how pollen beetles damage the plants to understand the limitations of the methods based on an estimation of the damage. RESULTS: We found that methods based on adult abundance lack robustness. We observed that most of the damage to buds is caused by pollen beetles feeding on small buds, and that this damage can be quantified later in the season, indicating the robustness of methods based on the count of podless stalks. Different methods gave consistent results and quantification of the pressure on the primary raceme can be a good proxy for data collected by assessing the whole plant. CONCLUSIONS: Standardized methods for assessment of pollen beetle pressure will enable comparison of pest management strategies between different studies and facilitate the development of alternative control strategies for this pest