307 research outputs found
Atomic and molecular data for spacecraft re-entry plasmas
The modeling of atmospheric gas, interacting with the space vehicles in re-entry conditions in planetary exploration missions, requires a large set of scattering data for all those elementary processes occurring in the system. A fundamental aspect of re-entry problems is represented by the strong non-equilibrium conditions met in the atmospheric plasma close to the surface of the thermal shield, where numerous interconnected relaxation processes determine the evolution of the gaseous system towards equilibrium conditions. A central role is played by the vibrational exchanges of energy, so that collisional processes involving vibrationally excited molecules assume a particular importance. In the present paper, theoretical calculations of complete sets of vibrationally state-resolved cross sections and rate coefficients are reviewed, focusing on the relevant classes of collisional processes: resonant and non-resonant electron-impact excitation of molecules, atom-diatom and molecule-molecule collisions as well as gas-surface interaction. In particular, collisional processes involving atomic and molecular species, relevant to Earth (N2, O2, NO), Mars (CO2, CO, N2) and Jupiter (H2, He) atmospheres are considered
HIPEC after Interval Debulking Surgery as Best Clinical Practice in Ovarian Cancer Patients: Case Series and Literature Review
Background: Hyperthermic intraperitoneal chemotherapy (HIPEC) combined with interval debulking surgery (IDS) constitutes an adjunctive treatment strategy in advanced ovarian cancer (AOC). This approach is based on the concept of perfusing chemotherapy targeting directly the site of residual tumor after optimal surgical debulking. It improves patients' outcome in terms of overall survival (OS) and disease free survival (DFS). The correct selection of patients eligible for IDS + HIPEC is crucial: in particular, they must have shown a good response to neoadjuvant chemotherapy (NACT) and have a good performance status (PS). The application of HIPEC at the end of debulking does not seem to increase neither the rate of intra/postoperative complications nor the time of hospitalization. Clinical Cases: After approving an internal protocol for the application of HIPEC in our hospital, we have submitted four patients to IDS + HIPEC in the past 12 months. One of these patients underwent a minimally invasive procedure. No intra- or postoperative complications were observed. Results: All patients underwent IDS + HIPEC after being assessed as eligible and after showing a good response to NACT. In the course of IDS in all cases complete debulking was achieved. No patient developed intra- or postoperative complications. Conclusions: The addition of HIPEC to interval debulking surgery should be offered to all eligible patients, considering that the association of HIPEC to IDS seems to improve patients' outcomes in terms of OS and DFS, without increasing post-operative morbidity
A measurement of the axial form factor of the nucleon by the p(e,e'pi+)n reaction at W=1125 MeV
The reaction p(e,e'pi+)n was measured at the Mainz Microtron MAMI at an
invariant mass of W=1125 MeV and four-momentum transfers of Q^2=0.117, 0.195
and 0.273 (GeV/c)^2. For each value of Q^2, a Rosenbluth separation of the
transverse and longitudinal cross sections was performed. An effective
Lagrangian model was used to extract the `axial mass' from experimental data.
We find a value of M_A=(1.077+-0.039) GeV which is (0.051+-0.044) GeV larger
than the axial mass known from neutrino scattering experiments. This is
consistent with recent calculations in chiral perturbation theory.Comment: 14 pages, 5 figures, uses elsart.cl
Catalytic pyrolysis of plastics over maghemite-impregnated mesocellular foam using induction heating
Pyrolysis is a key technology that converts unrecyclable end-of-life plastics into value-added products. Nevertheless, the high energy consumption during plastic pyrolysis limits the economic feasibility of a scaledup process. Development of an energy-efficient plastic pyrolysis process is necessary to realise its full potential in the circular economy. Catalysts derived from mesocellular foam possess high acidity and mesoporosity, and exhibit high catalytic activity in chemical reactions. Application of such catalyst in plastic pyrolysis has never been reported. This work presents the catalytic pyrolysis of low- and high-density polyethylene and polypropylene over maghemite-impregnated mesocellular foam (Fe@AlMCF). Fe@AlMCF has a BET surface
area of 629.8 m2/g and a strong Brønsted acidity (677 µmol/gcat). The catalyst contains pentagonal and hexagonal packed mesostructure. Induction heating resulted in a rapid increase in reactor temperature (at 65°C /min) and complete plastics conversion within 10 min. Catalytic pyrolysis produced gas products rich in C3 compounds. The liquid products were rich in alkenes (69.7-71.3 %) and alkanes, followed by aromatics (10.4- 12.8 %). These observations indicate that the highly acidic Fe@AlMCF catalysed hydrocarbon aromatization within a short reaction time. Thermal analysis of the spent catalysts revealed considerably high coke yields (5.78 - 6.03 %), as the higher acidity of the original catalyst promoted coke precursor formation. Based on the research findings, induction heating can rapidly and effectively convert plastics into hydrocarbon feedstocks, and Fe@AlMCF is a valuable catalyst for plastic pyrolysis
Air- and water-stable and photocatalytically active germanium-based 2D perovskites by organic spacer engineering
There is increasing interest in the role of metal halide perovskites for heterogeneous catalysis. Here, we report a Ge-based 2D perovskite material that shows intrinsic water stability realized through organic cation engineering. Incorporating 4-phenylbenzilammonium (PhBz) we demonstrate, by means of extended experimental and computational results, that PhBz2GeBr4 and PhBz2GeI4 can achieve relevant air and water stability. The creation of composites embedding graphitic carbon nitride (g-C3N4) allows a proof of concept for light-induced hydrogen evolution in an aqueous environment by 2D Ge-based perovskites thanks to the effective charge transfer at the heterojunction between the two semiconductors
Observation of weak neutral current neutrino production of
Observation of \jpsi production by neutrinos in the calorimeter of the CHORUS detector exposed to the CERN SPS wide-band \numu beam is reported. A spectrum-averaged cross-section = (6.3 3.0) is obtained for 20 GeV 200 GeV. The data are compared with the theoretical model based on the QCD Z-gluon fusion mechanism
Strangeness enhancement at mid-rapidity in Pb-Pb collisions at 158 GeV/c
, , , and negative particle yields and transverse mass spectra have been measured at central rapidity in Pb-Pb and p-Pb collisions at 158 GeV/. The yields in Pb-Pb interactions % are presented as a function of the collision centrality and compared with those obtained from p-Pb collisions. Strangeness enhancement in Pb-Pb relative to p-Pb collisions increases with the strangeness content of the particle. Going from p-Pb to Pb-Pb, the strange particle yields increase faster than linearly with the number of participants up to , thereafter the increase becomes %linear with . Yields are studied as a function of the number of nucleons participating in the collision , which is estimated with the Glauber model. From p-Pb to Pb-Pb collisions the particle yields per participant increase substantially. The enhancement is more pronounced for multistrange particles, and exceeds an order of magnitude for the . For a number of participants, , greater than , however, all yields per participant appear to be constant
The CHORUS neutrino oscillation search experiment
The CHORUS experiment has successfully finished run I (320~000 recorded \numu\ CC in 94/95) and performed half of run II (225~000 \numu\ CC in 96). The analysis chain was exercised on a small data sample for the muonic \tdecay\ search using for the first time fully automatic emulsion scanning. This pilot analysis, resulting in a limit \sintth \leq 3 \cdot 10^{-2}, confirms that the CHORUS proposal sensitivity (\sintth \leq 3 \cdot 10^{-4}) is within reach in two years
Observation of a first candidate in the OPERA experiment in the CNGS beam
The OPERA neutrino detector in the underground Gran Sasso Laboratory (LNGS)
has been designed to perform the first detection of neutrino oscillations in
direct appearance mode through the study of the
channel. The hybrid apparatus consists of an emulsion/lead target complemented
by electronic detectors and it is placed in the high energy long-baseline CERN
to LNGS beam (CNGS) 730 km away from the neutrino source. Runs with CNGS
neutrinos were successfully carried out in 2008 and 2009. After a brief
description of the beam, the experimental setup and the procedures used for the
analysis of the neutrino events, we describe the topology and kinematics of a
first candidate charged-current event satisfying the kinematical
selection criteria. The background calculations and their cross-check are
explained in detail and the significance of the event is assessed.Comment: 19 pages, 3 figure
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