Internally gelled w/o and w/o/w double emulsions

International audienceWater-in-oil emulsions having their aqueous internal phase gelled with starch were prepared and investigated. They were the primary emulsions requiredfor the preparation of double w/o/w emulsions that could encapsulate hydrophilic materials inside the internal aqueous gel. The emulsification could be achieved at high temperature in spite of the high viscosity of the aqueous phase; the internal phase gelled upon cooling to room temperature. The high viscosity of the aqueous phase limited the possible concentration range of starch in the aqueous phase. The presence of starch made the surfactant demand larger for both the emulsification and the stabilization of the w/o emulsions. The larger the starch content, the larger the amount of required surfactant. One reason for the high surfactant demand was the high viscosity of the aqueous phase containing starch. Another cause of high surfactant demand was disclosed and it appeared that predominantly theinteractions of the nonionic surfactants with starch retained the former inside theaqueous phase. The immobilized amount of surfactant had to be compensated by a supplementary concentration. Experimental evidence of the interactions between starch and the nonionic surfactants was given by interfacial tension measurements.Lastly, w/o/w double emulsions were prepared using the gelled w/o emulsions and a model hydrophilic molecule (caffeine) was encapsulated inside the internal gelledaqueous phase. The release rate of caffeine from the internally gelled double emulsions was slower than for the non-gelled emulsions, demonstrating theefficiency of the encapsulation and the possible control of the delivery

Internally gelled w/o and w/o/w double emulsions

International audienceWater-in-oil emulsions having their aqueous internal phase gelled with starch were prepared and investigated. They were the primary emulsions requiredfor the preparation of double w/o/w emulsions that could encapsulate hydrophilic materials inside the internal aqueous gel. The emulsification could be achieved at high temperature in spite of the high viscosity of the aqueous phase; the internal phase gelled upon cooling to room temperature. The high viscosity of the aqueous phase limited the possible concentration range of starch in the aqueous phase. The presence of starch made the surfactant demand larger for both the emulsification and the stabilization of the w/o emulsions. The larger the starch content, the larger the amount of required surfactant. One reason for the high surfactant demand was the high viscosity of the aqueous phase containing starch. Another cause of high surfactant demand was disclosed and it appeared that predominantly theinteractions of the nonionic surfactants with starch retained the former inside theaqueous phase. The immobilized amount of surfactant had to be compensated by a supplementary concentration. Experimental evidence of the interactions between starch and the nonionic surfactants was given by interfacial tension measurements.Lastly, w/o/w double emulsions were prepared using the gelled w/o emulsions and a model hydrophilic molecule (caffeine) was encapsulated inside the internal gelledaqueous phase. The release rate of caffeine from the internally gelled double emulsions was slower than for the non-gelled emulsions, demonstrating theefficiency of the encapsulation and the possible control of the delivery

Decay of the “Stretched” M4 Resonance in 13^{13}C

International audience“Stretched” states are examples of the simplest nuclear excitations in the continuum, thus offering an excellent testing ground for various theoretical approaches. The decay of the stretched single-particle state in 13C, located at 21.47 MeV, was investigated in an experiment performed recently at the Cyclotron Centre Bronowice (CCB) at IFJ PAN in Kraków. First experimental information on the proton and neutron decay channels of this resonance was obtained by employing coincidence measurement of protons inelastically scattered on the 13C target and γ rays from daughter nuclei. The new experimental findings will be used for testing predictions obtained by the Gamow Shell Model calculations

Decay of the “Stretched” M4 resonance in 13C

info:eu-repo/semantics/publishe

M4 Resonances in Light Nuclei Studied at CCB

International audienceM4 resonances in light nuclei result from the p3/2 → d5/2 stretched excitations. Their configurations should be relatively simple, which makes them good benchmarks for the theoretical calculations taking into account the role of continuum couplings. The first experimental studies aiming at tracing the decay of the M4 stretched resonance in 13C, located at 21.47 MeV, were undertaken at the Cyclotron Centre Bronowice at the Institute of Nuclear Physics Polish Academy of Sciences in Kraków, Poland (IFJ PAN). They provided information on the proton and neutron decay channels of this resonance to 12B and 12C daughter nuclei, respectively. These experimental results were then compared with the theoretical calculations based on the Gamow Shell Model approach, in terms of energy, width, and in particular, the decay pattern. Furthermore, the studies of the next cases, namely, 14N and 16O, where several M4 resonances appear at around 20 MeV, have been recently performed at CCB. The new experimental findings will serve as a testing ground for future calculations describing the heavier nuclei in this important region of the nuclear chart

M4 resonnaces in light nuclei studied at CCB

info:eu-repo/semantics/publishe

The decay of the 21.47-MeV stretched resonance in 13^{13}C: A precise probe of the open nuclear quantum system description

International audienceThe decay of the 21.47-MeV stretched resonance in 13C, arising from p3/2→d5/2 nucleon excitation coupled to maximum spin, was investigated in a (p,p′) experiment at 135 MeV proton bombarding energy, performed at the Cyclotron Centre Bronowice (CCB) at IFJ PAN in Krakow. First experimental information on the proton and neutron decay branches from this state was obtained by using coincidence measurement of protons inelastically scattered on a 13C target and γ rays from daughter nuclei, namely, 12B (proton decay) and 12C (neutron decay). The main branches lead to the Jπ=2+, first-excited state at 0.953 MeV in 12B, and to the Jπ=1+, T=1 level at 15.110 MeV in 12C. The results were compared with predictions from the Gamow Shell Model (GSM), which was used to describe the stretched resonance in terms of its energy, width, electromagnetic transition strengths and decay pattern. A very good agreement was obtained between the measured and calculated properties of the 21.47-MeV stretched resonance in 13C, demonstrating the high-quality and precision of the GSM wave function calculations, which include coupling to the resonant and non-resonant particle continuum