Cluster production is investigated in central collisions of Ca+Ca, Ni+Ni, 96Zr+96Zr, 96Ru+96Ru, Xe+CsI and Au+Au reactions at 0.4 AGeV incident energy. We find that the multiplicity of clusters with ...charge Z⩾3 grows quadratically with the system's total charge and is associated with a midrapidity source with increasing transverse velocity fluctuations. When reduced to the same number of available charges, an increase of cluster production by about a factor of 5.5 is observed in the midrapidity region between the lightest system (Ca+Ca) and the heaviest one (Au+Au). The results, as well as simulations using quantum molecular dynamics, suggest a collision process where droplets, i.e., nucleon clusters, are created in an expanding, gradually cooling, nucleon gas. Within this picture, expansion dynamics, collective radial flow and cluster formation are closely linked as a result of the combined action of nucleon–nucleon scatterings and the mean fields.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Purpose - Investigated milk fat fraction differs in physical attributes, first of all in melting point and solid fat content and its influence on crystallization process of cocoa butter i.e. ...chocolate mass. It means that this fraction slows down crystallization rate, decreases melting point of mixture with cocoa butter and causes chocolate softness. It is very important for quality of chocolate especially chocolate with nuts or sunflower kernel. The aim of this paper was to investigate the influence of low-melting (26°C) milk fat fraction on crystallization processes in chocolate mass and define the optimal concentration of this fraction with suitable precrystallization temperature time regime. Solid fat content of chocolate which designates the influence of precrystallization changes in chocolate mass with addition of milk fat fractions was investigated.Design methodology approach - The precrystallization was performed in a laboratory crystallizer that is in a modified Brabender pharinograph, which measures the rheological characteristics as indirect parameter of crystallization properties of chocolate mass depending on milk fat fraction concentration and precrystallization temperature. The experiments were performed according to the factorial plan 32 (two factors on three levels) and the results are statistically treated.Findings - The results showed that the optimal conditions for achieving the satisfactory tempering rate (optimal concentration of crystals in chocolate mass) are addition of 3 per cent low-melting milk fat fraction and precrystallization temperature of 25°C.Originality value - The addition of high-melting milk fat fraction slows down the chocolate mass crystallization more then low-melting milk fat fraction. Investigated fraction influenced decreasing in solid fat content of chocolate regardless of precrystallization temperature.
An overview is given over recent measurement of flow and particle production in the energy range from 0.1 to 2 AGeV. Excitation functions for the directed sideward and the azimuthally symmetric ...transverse flow are presented and show the importance of flow phenomena in this incident energy regime. Rapidity density distributions are indicative of a system size dependence of the stopping process. The role of strange particles as a probe for the hot and dense phase of hadronic matter is discussed with respect to the production and propagation. The spectra of Kaons indicate an equilibration with the surrounding baryons during the expansion while their directed flow pattern is different from that of the nucleons.
Full text
Available for:
IJS, IMTLJ, KILJ, KISLJ, NUK, SBCE, SBJE, UL, UM, UPCLJ, UPUK
To further study neutron-rich halo nuclei, we have constructed a neutron detector array. The array consists of two separate banks of detectors, each of area 2 × 2m
2 and containing 250l of liquid ...scintillator. Each bank is position-sensitive to better than 10 cm. For neutron time-of-flight measurements, the time resolution of the detector has been demonstrated to be about 1 ns. By using the scintillator NE-213, we are able to distinguish between neutron and γ-ray signals above 1 MeV electron equivalent energy. Although the detector array was constructed for a particular experiment it has also been used in a number of other experiments.
Full text
Available for:
IJS, IMTLJ, KILJ, KISLJ, NUK, SBCE, SBJE, UL, UM, UPCLJ, UPUK
New results on nuclear collective flow are presented for central and semi-central Ru + Ru collisions at 400
A MeV measured with the FOPI detector at GSI-Darmstadt. The source shape parameters, flow ...angle and aspect ratios, are extracted from Gaussian fits to in-plane and out-of-plane momentum distributions. The orientation and the shape of the source exhibit different trends according to the investigated phase space region. The shape parameters of the participant source are studied as a function of the particle mass and collision centrality. The flow angle is found to be independent of the particle mass. Both the flow angle and the aspect ratios depend sensitively on the impact parameter. Detailed comparisons with the predictions of the isospin quantum molecular dynamics model are performed. It is shown in particular that the source shape parameters permit to extract information on the in-medium nucleon–nucleon cross section.
Full text
Available for:
IJS, IMTLJ, KILJ, KISLJ, NUK, SBCE, SBJE, UL, UM, UPCLJ, UPUK
PDF
