Entity

Time filter

Source Type

Milano, Italy

Frison R.,CNR Institute of Crystallography | Cernuto G.,University of Insubria | Cervellino A.,Paul Scherrer Institute | Zaharko O.,Paul Scherrer Institute | And 3 more authors.
Chemistry of Materials | Year: 2013

Very small superparamagnetic iron oxide nanoparticles were characterized by innovative synchrotron X-ray total scattering methods and Debye function analysis. Using the information from both Bragg and diffuse scattering, size-dependent core-shell magnetite-maghemite compositions and full size (number- and mass-based) distributions were derived within a coherent approach. The magnetite core radii in 10 nm sized NPs well match the magnetic domain sizes and show a clear correlation to the saturation magnetization values, while the oxidized shells seem to be magnetically silent. Very broad superstructure peaks likely produced by the polycrystalline nature of the surface layers were experimentally detected in room temperature oxidized samples. Effective magnetic anisotropy constants, derived by taking the knowledge of the full size-distributions into account, show an inverse dependence on the NPs size, witnessing a major surface contribution. Finally, an additional amorphous component was uncovered within the diffuse scattering of the "ordered" magnetite-maghemite NPs. Under the hypothesis that this material may form an external dead layer, an additional thickness varying between 0.3 and 1.0 nm should be added to the overall core-shell NPs size. © 2013 American Chemical Society. Source


Copelli S.,University of Insubria | Torretta V.,University of Insubria | Lunghi A.,Innovhub | Derudi M.,Polytechnic of Milan | And 2 more authors.
Industrial and Engineering Chemistry Research | Year: 2013

Fast and strongly exothermic emulsion polymerization processes are particularly difficult to optimize from both safety and productivity points of view because of the occurrence of a number of undesired side reactions (e.g., propagation of tertiary radicals, chain transfer to monomer, backbiting, termination by disproportionation, etc.) and the triggering of boiling phenomena with consequent stable foam formation under atmospheric pressure. Therefore, it would be useful to develop a suitable combined theoretical and experimental procedure able to detect both the optimum process dosing time and initial reactor temperature. In this work, it is discussed how an extended version of the topological criterion theory, originally developed for isoperibolic semibatch reactors, can be used to safely optimize an indirectly cooled isothermal semibatch reactor. Moreover, such a methodology is applied to a case study represented by the synthesis of poly(butyl acrylate) through the radical emulsion polymerization of butyl acrylate. © 2013 American Chemical Society. Source


Copelli S.,University of Insubria | Torretta V.,University of Insubria | Pasturenzi C.,Innovhub | Derudi M.,Polytechnic of Milan | And 2 more authors.
Journal of Loss Prevention in the Process Industries | Year: 2013

It is well-known that, for certain values of the operative parameters influencing the dynamic behavior of a chemical reactor, a phenomenon known as thermal runaway (that is, a loss of the reactor temperature control) may arise. Such a situation can be really dangerous because above a certain threshold temperature value unwanted side reactions or, worse, decompositions of the reacting mixture may be triggered evolving high amounts of flammable or toxic gases that can cause reactor pressurization and, eventually, its explosion. For this reason, since the beginning of the previous century a number of studies concerning the prediction of the so called runaway boundaries has been carried out. In this work, a modified version of the divergence criterion for runaway detection, originally developed by Zaldívar and co-workers, is presented. Such a modified divergence criterion is capable of treating whatever type of complex controlled reacting system (taking into account not only temperature control but also dosing strategies) and its reliability has been demonstrated for isoperibolic semibatch reactors using literature experimental data concerning the nitration of 4-Chlorobenzotrifluoride in mixed acids and the nitric acid oxidation of 2-octanol to 2-octanone and further carboxylic acids. © 2013 Elsevier Ltd. All rights reserved. Source


Bondioli P.,Innovhub | Rivolta G.,Innovhub
Rivista Italiana delle Sostanze Grasse | Year: 2013

This short paper reports about the quantity and the composition of the liquid oil that can be obtained from Sarcophaga carnaria L larvae by means of hexane extraction. The obtained oil contains palmitic, palmitoleic, oleic and linoleic as the main fatty acids. In particular 2 different positional isomers of palmitoleic, for a total content of approx. 18% were detected. Data are reported about the sterol composition of oil. The residual meal is constituted of 70% of protein and could be of potential interest as a feed. The amino acid composition of the protein fraction is reported. Source


Chlapanidas T.,University of Pavia | Farago S.,Innovhub | Lucconi G.,University of Pavia | Perteghella S.,University of Pavia | And 8 more authors.
International Journal of Biological Macromolecules | Year: 2013

Some biological properties of Bombyx mori sericins from twenty strains were investigated, fourteen fed with artificial diet, two with fresh mulberry leaves and four with both diets. Sericin exhibited ROS-scavenging, anti-tyrosinase and anti-elastase properties, the strain significantly influenced these properties, while diet only influenced the anti-tyrosinase activity. Sericins were clustered into 5 groups and one sericin from each group was further studied: sericins showed anti-proliferative activity on in vitro stimulated peripheral blood mononuclear cells; some strains decreased in vitro secretion of IFNγ, while no effects were observed on TNFα and IL10 release.Therefore, a mixture of sericins extracted from the most promising strains may be useful for dermatological and cosmetic use. © 2013 Elsevier B.V. Source

Discover hidden collaborations