639 research outputs found
Static stability and axial force characteristics of a 1.32 percent scale model of the Saturn IB/Apollo, its components, and the Saturn IB/Apollo/Minuteman launch vehicle, determined by wind tunnel test
Wind tunnel stability tests of scale model Saturn IB/Apollo, and Saturn IB/Apollo/ Minuteman launch vehicl
The Dark Side of the Littlest Seesaw: freeze-in, the two right-handed neutrino portal and leptogenesis-friendly fimpzillas
We propose a minimal model to simultaneously account for a realistic neutrino
spectrum through a type-I seesaw mechanism and a viable dark matter relic
density. The model is an extension of the Littlest Seesaw model in which the
two right-handed neutrinos of the model are coupled to a -odd dark sector
via right-handed neutrino portal couplings. In this model, a highly constrained
and direct link between dark matter and neutrino physics is achieved by
considering the freeze-in production mechanism of dark matter. We show that the
neutrino Yukawa couplings which describe neutrino mass and mixing may also play
a dominant role in the dark matter production. We investigate the allowed
regions in the parameter space of the model that provide the correct neutrino
masses and mixing and simultaneously give the correct dark matter relic
abundance. In certain cases the right-handed neutrino mass may be arbitrarily
large, for example in the range GeV required for vanilla
leptogenesis, with a successful relic density arising from frozen-in dark
matter particles with masses around this scale, which we refer to as
"fimpzillas".Comment: 24 pages, 5 figures. v2: version to appear in JCA
CleAir monitoring system for particulate matter. A case in the Napoleonic Museum in Rome
Monitoring the air particulate concentration both outdoors and indoors is becoming a more relevant issue in the past few decades. An innovative, fully automatic, monitoring system called CleAir is presented. Such a system wants to go beyond the traditional technique (gravimetric analysis), allowing for a double monitoring approach: the traditional gravimetric analysis as well as the optical spectroscopic analysis of the scattering on the same filters in steady-state conditions. The experimental data are interpreted in terms of light percolation through highly scattering matter by means of the stretched exponential evolution. CleAir has been applied to investigate the daily distribution of particulate matter within the Napoleonic Museum in Rome as a test case
Tradition and innovation in the water buffalo dairy products
AbstractThe first part of a two-part synthesis paper focuses on current research on optimization of Mozzarella cheese manufacture. Starting from technology of traditional cheese points susceptible of modification are identified for achieving greater yield and improving quality. In addition ingredients are identified which can enhance quality and performance characteristic of cheese also in term of economy. The second part considers the development of new cheese varieties whose technology has been developed in bovine milk. Water buffalo cheese reproducing bovine counterpart varieties like Gorgonzola, Grana, Asiago, Taleggio has been developed and are commercially available. Yogurt, and kefir, have also developed to enrich the panel of water buffalo dairy products
Linear conduction in N-type organic field effect transistors with nanometric channel lengths and graphene as electrodes
In this work, we test graphene electrodes in nanometric channel n-type Organic Field Effect Transistors (OFETs) based on thermally evaporated thin films of the perylene-3,4,9,10-tetracarboxylic acid diimide derivative. By a thorough comparison with short channel transistors made with reference gold electrodes, we found that the output characteristics of the graphene-based devices respond linearly to the applied bias, in contrast with the supralinear trend of gold-based transistors. Moreover, short channel effects are considerably suppressed in graphene electrode devices. More specifically, current on/off ratios independent of the channel length (L) and enhanced response for high longitudinal biases are demonstrated for L down to 3c140 nm. These results are rationalized taking into account the morphological and electronic characteristics of graphene, showing that the use of graphene electrodes may help to overcome the problem of Space Charge Limited Current in short channel OFETs
Could nearby star-forming galaxies light up the point-like neutrino sky?
Star-forming and starburst galaxies, which are well-known cosmic-rays
reservoirs, are expected to emit gamma-rays and neutrinos predominantly via
hadronic collisions. In this Letter, we analyze the 10-year Fermi-LAT spectral
energy distributions of 13 nearby galaxies by means of a physical model which
accounts for high-energy proton transport in starburst nuclei and includes the
contribution of primary and secondary electrons. In particular, we test the
hypothesis that the observed gamma-ray fluxes are mostly due to star-forming
activity, in agreement with the available star formation rates coming from IR
and UV observations. Through this observation-based approach, we determine the
most-likely neutrino counterpart from star-forming and starburst galaxies and
quantitatively assess the ability of current and upcoming neutrino telescopes
to detect them as point-like sources. Remarkably, we find that the cores of the
Small Magellanic Cloud and the Circinus galaxy are potentially observable by
KM3NeT/ARCA with 6 years of observation. Moreover, most of the nearby galaxies
are likely to be just a factor of a few below the KM3NeT and IceCube-Gen2
point-like sensitivities. After investigating the prospects for detection of
gamma-rays above TeV energies from these sources, we conclude that the joint
observations of high-energy neutrinos and gamma-rays with upcoming telescopes
will be an objective test for our emission model and may provide compelling
evidence of star-forming activity as a tracer of neutrino production.Comment: 7 pages, 2 figure
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