284 research outputs found
Waste Minimization by Reuse and Recycling
Recently, pollution prevention directs attention towards the elimination or reduction of undesired by- products within the production process itself before treatment. On the long term, pollution prevention through waste minimization and cleaner production is more cost-effective and environmentally sound than traditional pollution control methods.
The objective of this work was to carry out a feasibility study to define and implement an integrated pollution prevention and control measure in order to minimize waste and therefore to achieve compliance with the Romanian Environmental law
Path integral Monte Carlo simulation of charged particles in traps
This chapter is devoted to the computation of equilibrium (thermodynamic)
properties of quantum systems. In particular, we will be interested in the
situation where the interaction between particles is so strong that it cannot
be treated as a small perturbation. For weakly coupled systems many efficient
theoretical and computational techniques do exist. However, for strongly
interacting systems such as nonideal gases or plasmas, strongly correlated
electrons and so on, perturbation methods fail and alternative approaches are
needed. Among them, an extremely successful one is the Monte Carlo (MC) method
which we are going to consider in this chapter.Comment: 18 pages, based on talks on Hareaus school on computational methods,
Greifswald, September 200
Interaction potential between dynamic dipoles: polarized excitons in strong magnetic fields
The interaction potential of a two-dimensional system of excitons with
spatially separated electron-hole layers is considered in the strong magnetic
field limit. The excitons are assumed to have free dynamics in the -
plane, while being constrained or `polarized' in the direction. The model
simulates semiconductor double layer systems under strong magnetic field normal
to the layers. The {\em residual} interaction between excitons exhibits
interesting features, arising from the coupling of the center-of-mass and
internal degrees of freedom of the exciton in the magnetic field. This coupling
induces a dynamical dipole moment proportional to the center-of-mass magnetic
moment of the exciton. We show the explicit dependence of the inter-exciton
potential matrix elements, and discuss the underlying physics. The unusual
features of the interaction potential would be reflected in the collective
response and non-equilibrium properties of such system.Comment: REVTEX - 11 pages - 1 fi
New pathway to bypass the 15O waiting point
We propose the sequential reaction process
O(,)O as a new pathway to bypass of the
O waiting point. This exotic reaction is found to have a surprisingly
high cross section, approximately 10 times higher than the
O(,)O. These cross sections were calculated after
precise measurements of energies and widths of the proton-unbound F low
lying states, obtained using the H(O,p)O reaction. The large
cross section can be understood to arise from the more
efficient feeding of the low energy wing of the ground state resonance by the
gamma decay. The implications of the new reaction in novae explosions and X-ray
bursts are discussed.Comment: submitte
Experimental investigation of the effect of ionization on the 51V(p,n)51Cr reaction
The investigation of the effects of average atomic ionization on nuclear
reactions is of prime importance for nuclear astrophysics. No direct
experimental measurement using a plasma target has been done yet. In this
regard, we measured for the first time the neutron production of a (p,n)
reaction in different states of ionization. The studied nuclear reaction was
51V(p,n)51Cr. We measured a significantly lower neutron production than
expected when the target was ionized, even when taking into account existing
electron screening theory or the effect of the stopping power in the target on
the injected proton beam. This experiment is a first step in the process to
characterize the influence of ionization at astrophysically relevant energies.Comment: 20 pages, 10 figures, submitted to EP
Probing Nuclear forces beyond the drip-line using the mirror nuclei N and F
Radioactive beams of O and O were used to populate the resonant
states 1/2, 5/2 and in the unbound F and F
nuclei respectively by means of proton elastic scattering reactions in inverse
kinematics. Based on their large proton spectroscopic factor values, the
resonant states in F can be viewed as a core of O plus a proton
in the 2s or 1d shell and a neutron in 1p. Experimental
energies were used to derive the strength of the 2s-1p and
1d-1p proton-neutron interactions. It is found that the former
changes by 40% compared with the mirror nucleus N, and the second by
10%. This apparent symmetry breaking of the nuclear force between mirror nuclei
finds explanation in the role of the large coupling to the continuum for the
states built on an proton configuration.Comment: 6 pages, 3 figures, 2 tables, accepted for publication as a regular
article in Physical Review
Spectroscopy of Na: shell evolution toward the drip line
Excited states in Na have been studied using the -decay of
implanted Ne ions at GANIL/LISE as well as the in-beam -ray
spectroscopy at the NSCL/S800 facility. New states of positive
(J=3,4) and negative (J=1-5) parity are proposed. The
former arise from the coupling between 0d protons and a 0d
neutron, while the latter are due to couplings with 1p or 0f
neutrons. While the relative energies between the J=1-4 states are
well reproduced with the USDA interaction in the N=17 isotones, a progressive
shift in the ground state binding energy (by about 500 keV) is observed between
F and Al. This points to a possible change in the proton-neutron
0d-0d effective interaction when moving from stability to the
drip line. The presence of J=1-4 negative parity states around 1.5
MeV as well as of a candidate for a J=5 state around 2.5 MeV give
further support to the collapse of the N=20 gap and to the inversion between
the 0f and 1p levels below Z=12. These features are discussed
in the framework of Shell Model and EDF calculations, leading to predicted
negative parity states in the low energy spectra of the F and O
nuclei.Comment: Exp\'erience GANIL/LISE et NSCL/S80
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Exploring the feasibility of ex-post harmonisation of religiosity items from the European Social Survey and the European Values Study
This paper examines the feasibility of ex-post harmonisation strategies using European Values Study (EVS) Wave 5 (2017–2020) and European Social Survey (ESS) Round 9 (2018–2019) data across 17 countries. The study shows an empirical assessment of the comparability of four items measuring religious behaviours (belonging to a religious denomination at present/in the past, religious services attendance, and praying), captured in both surveys. The novelty of this paper lies in the analytical comparison of religiosity indicators that are rarely assessed from a comparative perspective.The harmonisation strategy was based upon several analytical techniques that seek to determine similarities and differences between the selected items in terms of (a) their validity, by examining their correlations with a set of sociodemographic and substantive correlates, (b) their distributions, supplemented by visual comparisons and relevant statistical tests, and (c) item non-substantive shares. The findings pointed to the most consistency among the partial correlations, where individual religiosity produced the most differences between the surveys. Distributions produced the most discrepancies that also corresponded to less similarity across variable categories as gauged by Duncan’s index. This paper is descriptive and exploratory in its aim. It can be taken as a jumping-off point for future research where the time series of these two surveys, and potentially others, can be examined across aggregate levels (e.g. birth cohorts, countries)
Initial State Dependence of the Breakup of Weakly Bound Carbon Isotopes
The one-neutron nuclear breakup from the Carbon isotopes C and
C, is calculated as an example of application of the theory of transfer
to the continuum reactions in the formulation which includes spin coupling.
The effect of the energy sharing between the parallel and transverse neutron
momentum distributions is taken into account thus resulting in a theory which
is more general than sudden eikonal approaches. Both effects are necessary to
understand properly the breakup from not too weakly bound orbitals.
Breakup which leaves the core into an excited state below particle threshold is
also considered. The core-target interaction is treated in the smooth cut-off
approximation. By comparing to presently available experimental data we show
how to make some hypothesis on the quantum numbers and occupancy of the neutron
initial state. Possible ambiguities in the interpretation of inclusive cross
sections are discussed.Comment: 22 RevTeX pages,3 ps figures. Phys. Rev. C, accepte
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