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Up to 20% of ethanol, base oil, or gas condensates are sometimes illegally added with the purpose to produce a cheaper fuel at the expense of its quality. Fuels are more expensive compared with the additives mentioned above due to the excise taxes and duties levied. Common customs procedures include random fuel sampling, where the tanks of trucks are opened at border crossings to verify that the cargo complies with customs declarations. Although some rapid onsite testing is available, very often more detailed laboratory analysis of fuel samples is required, the results of which may not be available for several days. We have investigated the possibility of using a neutron-based system to determine the elemental composition and density of gasoline, diesel, and various fuel blends, such as gasoline/ethanol, diesel/base oil, and diesel/gas condensate. It has been shown that using the associate particle imaging (API) method, it is possible to analyze elemental composition and density of different fuel types and various kinds of fuel blends onsite, without opening fuel tanks and slowing down border traffic. These analyses can be performed in addition to the already well-developed API method for onsite cargo inspection of illicit materials, such as narcotics and explosives.

Abstract:: The ratio of K- to K+-meson yields has been measured in the systems 96Ru + 96Ru at 1.69 A GeV, 96Ru+96Zr at 1.69 A GeV, and 58Ni+58Ni at 1.93 A GeV incident beam kinetic energy. The yield ratio is observed to vary across the measured phase space. Relativistic transport-model calculations indicate that the data are best understood if in-medium modifications of the kaons are taken into account.

Abstract.: The mass distributions of baryon resonances populated in near-central collisions of Au on Au and Ni on Ni are deduced by defolding the pt spectra of charged pions by a method which does not depend on a specific resonance shape. In addition the mass distributions of resonances are obtained from the invariant masses of (p, π±) pairs. With both methods the deduced mass distributions are shifted by an average value of −60 MeV/c2 relative to the mass distribution of the free Δ(1232) resonance, the distributions descent almost exponentially towards mass values of 2000 MeV/c2. The observed differences between (p, π−) and (p, π+) pairs indicate a contribution of isospin I = 1/2 resonances. The attempt to consistently describe the deduced mass distributions and the reconstructed kinetic energy spectra of the resonances leads to new insights about the freeze out conditions, i.e. to rather low temperatures and large expansion velocities.

Charged pions are measured with the 4π detector FOPIat GSIusing the Au on Au reaction at 1.06 AGeV bombarding energy. The pion multiplicities ngpincrease with the number of participants Apart. The average pion multiplicities per participant are #### and #### These values are only half as large as extrapolated from the low-mass systems studied by Harris et al. The ratio #### increases with Apartand decreases with the pion kinetic energies. The pion kinetic energy spectra have concave shapes, their parametrization in terms of thermal Boltzmann distributions yields a low (Tl,π) and high (Th,π) temperature which change with the cm emission angle Θ of the pions. In the angular range 45dg < Θ< 135° the low temperature < Tl,π−> is larger than < Tl,π+>, the high temperatures < Th,π−>, < Th,π+> are, within experimental uncertainties, the same. The inclusive polar angular distributions of pions are anisotropic, dσ/dΩincreases for forward and backward angles. The forward — backward enhancements are independent of the pion kinetic energies or the number of participants. In addition to the preferred forward — backward emission, also the enhanced emission into the transverse direction Θ =90° is observed for pions with high energies or for pions from near-central collisions. These observations and the shape of the rapidity spectra suggest that pions, emitted from the central rapidity region, are partly rescattered by spectator matter. The strength of the rescattering process depends only weakly on the number of participants. The experimental data are compared to the results of IQMD/GEANTcalculations using momentum dependent NNinteractions and a hard equation of state. The calculated pion multiplicities are approximately 50% larger than experimentally determined; the existence of secondary pion sources is reproduced by the calculation, but their predicted strengths are larger than experimentally observed.

The preequilibrium emission of nucleons from reactions induced by medium-energy heavy ions is analyzed by using (i) the first term of the Griffin-exciton-model expansion and (ii) the modified Harp-Miller-Berne equilibration model. It is shown that both models account well for the high-energy component of angle-integrated emission spectra. The values of the relevant parametern0 (initial number of degrees of freedom which share the available energy), obtained from the analysis with the two models, are practically equal for each reaction studied. The best-fit values ofn0 depend on the incident energy. This behaviour is a novel feature of preequilibrium emission mechanisms in heavy-ion reactions, hitherto unobserved in light-ion reactions.

Experimental inclusive proton spectra of58Ni+60Ni at 15.1 MeV/u have been decomposed using three moving sources associated with, respectively, equilibrium, deep-inelastic, and preequilibrium processes. For the last, a new expression, taking into account the anisotropy of preequilibrium particles in the source system, has been applied. The high-energy part of the obtained angle-integrated proton spectrum has been compared with predictions of the diabatic dissipation model.