81 research outputs found
Investigating the inclusive transverse spectra in high-energy collisions in the context of geometric scaling framework
The presence of geometric scaling within the spectra of produced
hadrons at high energy collisions using small- -factorization is
investigated. It is proposed a phenomenological parameterization for the
unintegrated gluon distribution in the scaling range which reproduces the
features of the differential cross section both in the saturated and dilute
perturbative QCD regimes. As the saturation scale acts as an effective
regulator of the infrared region (IR), the extension of the model to quantities
usually associated to soft physics is studied. The approach is applied to
compute the average and the rapidity distribution of produced gluons at
high energies.Comment: 11 pages, 9 figure
Chemical functionalization of graphene surface as filler for rubber compounds
Over the last few years, the surface modification of fillers for high-level technological applications such as polymer composites for tyre industry, conductive inks and coatings has seen a considerable increase in interest since it can increase mechanical, electrical, and thermal properties of the final material. Nano-sized carbon allotropes such as graphene and carbon nanotubes are a suitable class of compounds for these purposes: high thermal and electrical conductivity along with considerable mechanical reinforcement are the main improvements that these fillers bring to the composite and their elevated surface area allows to reduce the filler volume ratio compared to more common alternatives. An efficient and reliable method to modify the surface of these nano-fillers is the so-called pyrrole methodology, a mild procedure that involves bio-sourced reagents to introduce functional groups on the graphitic planes and that has been recently employed in the fabrication of elastomeric composites with improved mechanical properties. In order to understand the mechanism beneath the interaction between the pyrrole and the substrate and thus the behavior of the functionalized filler, a more in-depth analysis is requested. A theoretical work based on molecular dynamics simulations and a DFT study were performed in order to investigate the interaction energy, the geometry of interaction and the mobility of N-substituted pyrrole molecules adsorbed on the graphene planes. This theoretical study at atomistic level can help design a new class of high-performance fillers by better understanding the interaction mechanism given the important role of supramolecular interactions
Investigating the diffractive gluon jet production in lepton-ion collisions
We study the diffractive jet production in electron-ion collisions in the
kinematical region where the mass of the diffractive final state is
larger than . Based on parton saturation framework predictions are done
for the kinematics of future or possible machines as the EIC, LHeC,
HE-LHeC and FCC-eA. We analyze the differential cross section as a function of
jet (gluon) transverse momentum and from the experimental point of view this
observable could be used to extract the saturation scale as a function of
.Comment: 8 pages, 5 figures. To be published in Physical Review
Role of nuclear gluon distribution on particle production in heavy ion collisions
The transverse momentum spectra of hadrons is calculated from the
unintegrated gluon distribution (UGD) within the -factorization framework
at small . Starting from collisions, the modification caused by the
nuclear medium is incorporated in the UGD at high energies, which is related to
the nuclear shadowing phenomenon. Moreover, we consider that particle
production from minijet decaying is not enough to explain the spectra in
collisions due to collective phenomena that take place after the hard
collision. The Boltzmann-Gibbs Blast Wave (BGBW) distribution is utilized in
order to evaluate the distribution of particle production in equilibrium. Data
from ALICE collaboration for collisions at TeV are
analyzed and the nuclear modification factor for pion production is computed.Comment: 8 pages, 5 figure
Dilepton production through timelike Compton scattering within the -factorization approach
In this work we consider the dilepton production via timelike Compton
scattering (TCS) in electron-proton and proton-proton collisions. In
particular, the differential cross section in terms of the dilepton invariant
mass and rapidity is computed within the -factorization approach. Besides,
we utilize distinct unintegrated gluon distributions (UGD) in order to compare
their impact on the differential cross section of TCS in () collisions
evaluated at the LHC (LHeC), HL-LHC (LHeC), HE-LHC (LHeC) and FCC-hh (eh)
center-of-mass energies.Comment: 9 pages, 4 figure
Transition metal nanoparticles on pyrrole-decorated sp2 carbon allotropes for selective hydrogen isotopic exchange
Compared to homogeneous catalysts, heterogeneous systems possess more attractiveness in the chemical industry because of the easier separation from the reaction products, lower amount of wastes, larger recyclability and lower toxicity and corrosiveness. Preparation of supported metal nanoparticles often requires energy demanding techniques such as laser ablation, electrochemical reduction, and high temperature heat treatments. In this work we present a facile and sustainable method to functionalize multi-walled carbon nanotubes (MWCNTs) and exploit the novel surface reactivity to deposit Ruthenium nanoparticles. Serinol pyrrole (SP) was synthesized and, through a Domino reaction, grafted on carbon nanotubes’ surface. Mild reducing conditions were employed to decorate CNT-SP with Ruthenium nanoparticles. The latter adduct was characterized by means of X-ray diffraction and transmission electron microscopy. Ru/CNT-SP was then tested in the selective deuteration of quinoline. High selectivity and conversion, determined through H-NMR, were achieved compared to commercial Ru/C catalysts. The results obtained in this work led to the filing of two patent applications
Transition metal nanoparticles on pyrrole-decorated sp2 carbon allotropes for selective hydrogen isotopic exchange
Compared to homogeneous catalysts, heterogeneous systems possess more attractiveness in the chemical industry because of the easier separation from the reaction products, lower amount of wastes, larger recyclability, and lower toxicity and corrosiveness.
Objective of this research was to prepare more efficient and more selective heterogeneous catalysts, by anchoring transition metal cations and nanoparticles on nitrogen decorated sp2 carbon allotrope (CA), which were functionalized with pyrrole compounds. Triethylenetetramine pyrrole (TETAP) was selected as the pyrrole compound: it was synthesized and grafted onto multiwalled carbon nanotubes and high surface area graphite with efficient and viable methodology.
The CA/TEPAP adduct was used as the support of transition metal nanoparticles.
It is here reported the example of ruthenium supported catalyst, investigated by means of elemental and surface area analyses, X-ray diffraction, transmission electron microscopy. The catalyst was used for the Hydrogen Isotopic Exchange (HIE) of aromatic compounds of pharmaceutical interest.
Outstanding selectivity was obtained
Difference between stable and exotic nuclei: medium polarization effects
The bare NN-potential, parametrized so as to reproduce the nuclear phase
shifts leads to a sizable Cooper pair binding energy in nuclei along the
stability valley. It is a much debated matter whether this value accounts for
the "empirical" value of the pairing gap or whether a similarly important
contribution arises from the exchange of collective vibrations between Cooper
pair partners. In keeping with the fact that two-particle transfer reactions
are the specific probe of pairing in nuclei, and that exotic halo nuclei like
11Li are extremely polarizable, we find that the recent studied reaction,
namely 11Li+p -> 9Li+t, provides direct evidence of phonon mediated pairing in
nuclei
Precision-based exercise as a new therapeutic option for children and adolescents with haematological malignancies
Children and adolescents with haematological malignancies (pedHM) are characterized by a severe loss of exercise ability during cancer treatment, lasting throughout their lives once healed and impacting their social inclusion prospects. The investigation of the effect of a precision-based exercise program on the connections between systems of the body in pedHM patients is the new frontier in clinical exercise physiology. This study is aimed at evaluating the effects of 11 weeks (3 times weekly) of combined training (cardiorespiratory, resistance, balance and flexibility) on the exercise intolerance in PedHM patients. Two-hundred twenty-six PedHM patients were recruited (47% F). High or medium frequency participation (HAd and MAd) was considered when a participant joined; > 65% or between 30% and < 64% of training sessions, respectively. The \u201cup and down stairs\u2019\u2019 test (TUDS), \u201c6 min walking\u201d test (6MWT), the \u201c5 Repetition Maximum strength\u201d leg extension and arm lateral raise test (5RM-LE and 5RM-ALR), flexibility (stand and reach), and balance (stabilometry), were performed and evaluated before and after training. The TUDS, the 5RM-LE and 5RM-ALR, and the flexibility exercises showed an increase in HAd and MAd groups (P < 0.05), while the 6MWT and balance tests showed improvement only in HAd group (P < 0.0001). these results support the ever\u2010growing theory that, in the case of the treatment of PedHM, \u2018exercise is medicine\u2019 and it has the potential to increase the patient\u2019s chances of social inclusion
A Fluorous-Tagged “Safety Catch” Linker for Preparing Heterocycles by Ring-Closing Metathesis
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