69 research outputs found
Domenico Muzzi, schede nn. 36-37
No full textLe due schede si concentrano sui bozzetti preparatori ad acquerello per la decorazione della cupola di San Liborio a Colorno di Domenico Muzzi (1742-1812
Investigation of synthetic strategies for enhancing the energy product of spinel ferrite nanoparticles
No full textThis work was focused on the development of synthesis strategies for enhancing the energy product of spinel ferrite nanoparticles. The final goal was that of finding the best conditions to realize novel materials with improved magnetic properties, which could be used as building blocks for the realization of rare earth free - permanent magnet with higher energy products than commercial ferrites (i.e. strontium ferrite). To this aim, we focused on quasi-zero-dimensional magnetic materials and as possible strategies to enhance their performances we explored the coupling at the nanoscale with magnetic components endowed with complementary properties, and the modification of the intrinsic core properties by solvent mediated post-synthetic treatment.
In the first part of this work, hybrid nanocomposite magnets were designed, where the effective exchange-coupling through the interface between hard and soft magnetic constituents or between AFM and a F(i)M phases is exploited to increase the energy product of the material. In particular, metal/ferrite nano-heterostructures, NHSs, were synthesized by an optimized one-pot thermal decomposition method, which allowed us to tune the composition of the final product by tuning the synthetic parameters. The best NHSs obtained by this approach had energy product of 19 kJm-3, higher than that of the commercial hexagonal ferrite. With the aim of developing a system able to display exchange bias at room temperature, iron oxide AFM|FiM core|shell (CS) NPs doped with two divalent cations (Co(II) and Ni(II)) were also synthetized. The co-doping with cobalt and nickel revealed to be a good compromise for obtaining nanocrystals stable to further oxidation processes, and with increased anisotropy, bias and Néel temperature (260 K) than the standard CS iron oxide NPs.
The second part of the thesis was devoted to the improvement of the magnetic performances of the prepared CS AFM|F(i)M hybrid NPs and of standard cobalt ferrites NPs, by solvent mediated post-synthesis treatments. In the first case a mild oxidation of the Fe0.95O|Fe3O4, Co0.3Fe0.7O|Co0.8Fe2.2O4 and Ni0.17Co0.21Fe0.62O|Ni0.4Co0.3Fe2.3O4 CS NPs was realized by solvent mediated annealing in the presence of air, with the aim of investigating the role of the nature of the divalent ions on the structure and room temperature magnetic behaviour of the oxidized product. The Ni(II) and Co(II) amount during the oxidation process was found to play a crucial role in the formation of crystalline antiphase boundaries, leading to a mosaic texturing of the spinel structure in the NPs, characterized by enhanced exchange bias and high field magnetization with respect to the standard AFM|F(i)M NPs. The second investigated approach was the solvent mediated annealing treatment of standard cobalt ferrites NPs. This approach has proven to be an excellent strategy for increasing of the 48 % the BHmax value of the material thanks to the reduction of the lattice microstrain generated during the crystallites’ growth. The presented results provide indications on the validity of the proposed approaches. A further investigation is required to obtain materials characterized by exchange effect at room temperatures through a synthesis that can be carried out on a large scale
Two novel approaches to study arthropod anatomy by using dualbeam FIB/SEM. Corresponding author
No full textTransmission Electron Microscopy (TEM) has always been the conventional method to study arthropod ultrastructure, while the use of Scanning Electron Microscopy (SEM) was mainly devoted to the examination of the external cuticular structures by secondary electrons. The new generation field emission SEMs are capable to generate images at sub-cellular level, comparable to TEM images employing backscattered electrons. The potential of this kind of acquisition becomes very powerful in the dual beam FIB/SEM where the SEM column is combined with a Focused Ion Beam (FIB) column. FIB uses ions as a nano-scalpel to slice samples fixed and embedded in resin, replacing traditional ultramicrotomy. We here present two novel methods, which optimize the use of FIB/SEM for studying arthropod anatomy
GREEN NANOMATERIAL SYNTHESIS VIA RF SPUTTERING IN LIQUIDS AND ONTO POWDERS FOR SCALABLE, CRM-FREE CATALYSTS FOR WATER ELECTROLYSIS
No full textWe presented a dry and green synthesis approach using RF magnetron sputtering, a physical vapor deposition (PVD) technique, to fabricate nanofluids (nanoparticles suspended in liquids) and nanohybrids (catalyst-coated powders) as catalysts for water electrolysis applications. This solvent-free method eliminates hazardous chemicals and complex multi-step procedures, enabling sustainable and scalable production of ultrapure catalysts. For nanohybrids, copper-coated multi-walled carbon nanotubes (Cu/CNTs) and nickel-coated titania nanopowders (Ni/TiO2) were synthesized via RF magnetron sputtering combined with a vibrating deposition stage, which ensured uniform nanoparticle coating.1 For nanofluids, ultrapure nanoparticles (gold, copper, nickel, platinum) were obtained by RF sputtering directly into a liquid medium, preserving their native nanoscale morphology.2 These nanoparticles were then seamlessly transferred onto functional substrates such as Nafion membranes and graphene, forming uniform catalyst-coated membranes (CCM) and nanohybrids with ultra-low precious metal loading at the nanogram scale. Comprehensive characterization using SEM-EDX, XPS, XRD, AFM, and TEM confirmed nanoparticle integrity and dispersion. Electrochemical tests demonstrated an excellent hydrogen evolution reaction (HER) performance, comparable to commercial Pt-based materials. Therefore, this process addresses key challenges in PEM electrolyzer technology by lowering material costs, and offering a green, scalable, and industrially viable fabrication route
Functional anatomy of the explosive defensive system of bombardier beetles (Coleoptera, Carabidae, Brachininae). Corresponding author
No full textThis paper provides the first comparative anatomical study of the explosive pygidial defensive system of bombardier beetles in species classified in three brachinine subtribes: Brachinus (Brachinina), Pheropsophus (Pheropsophina) and Aptinus (Aptinina). We investigated the morphology and ultrastructure of this system using optical, fluorescence, and focused ion beam (FIB/SEM) microscopy. In doing so, we characterized and comparatively discussed: (1) the ultrastructure of the gland tissues producing hydroquinones and hydrogen peroxide (secretory lobes), and those producing catalases and peroxidases (accessory glands); (2) the complex anatomy of the collecting duct; (3) the arrangement of the muscular bundles and the folding of the cuticle of the reservoir, suggesting a functional division of this chamber (dynamic part and storage part); (4) the great structural diversity of sculpticles inside the reaction chamber, where we could recognize six main types of microsculpture located in specific districts of the chamber. Additionally, using fluorescence microscopy, we highlighted the presence of resilin in two structures strongly subjected to mechanical stress during the discharge, the valve and the turrets of the reaction chamber. The results of this paper give a solid anatomic overview of the most popular beetle defensive system, contributing to the debate on its evolution within the Carabidae
The non-univocity of the concept of “author” from the perspective of Wittgenstein and Foucault
No full textDue mainly to the Information and Communication Technologies (ICT), the concept of “author” and possibilities of authorship have been broadened, regardless of the area in which the content is created. From the perspective of Wittgenstein’s “language games” and Foucault’s concept of “author,” we analyze the uses, reuses and resignifications attributed to the concept of “author” in the areas of Law, Engineering and, Library Science. We found a non-univocity of the concept based on its transformations and changes over time according to the rules and conventions of each area.Departamento de Ciência da Informação Universidade Estadual Paulista, Av. Hygino Muzzi Filho, 737Departamento de Ciência da Informação Universidade Estadual Paulista, Av. Hygino Muzzi Filho, 73
Can anti-cocitations also measure author relatedness?
No full textSão Paulo State University (UNESP), Av. Hygino Muzzi Filho 737University of Wisconsin-Milwaukee, P.O. Box 413São Paulo State University (UNESP), Av. Hygino Muzzi Filho 73
The non-univocity of the concept of author from the perspective of Wittgenstein and Foucault
No full textDue mainly to the Information and Communication Technologies (ICT), the concept of author and possibilities of authorship have been broadened, regardless of the area in which the content is created. From the perspective of Wittgenstein's language games and Foucault's concept of author, we analyze the uses, reuses and resignifications attributed to the concept of author in the areas of Law, Engineering and, Library Science. We found a non-univocity of the concept based on its transformations and changes over time according to the rules and conventions of each area.Univ Estadual Paulista, Dept Ciencia Informacao, Av Hygino Muzzi Filho 737, Marilia, SP, BrazilUniv Estadual Paulista, Dept Ciencia Informacao, Av Hygino Muzzi Filho 737, Marilia, SP, Brazi
Can Anti-Cocitations Also Measure Author Relatedness?
No full textSao Paulo State Univ UNESP, Av Hygino Muzzi Filho 737, BR-17525900 Marilia, SP, BrazilUniv Wisconsin, POB 413, Milwaukee, WI 53201 USASao Paulo State Univ UNESP, Av Hygino Muzzi Filho 737, BR-17525900 Marilia, SP, Brazi
Studies of Author Cocitation Analysis: A Bibliometric Approach for Domain Analysis
No full textAuthor Cocitation Analysis (ACA) can be defined as the analysis of a group of actors, writers or researchers structurally organized in a (social and cognitive) network of a particular scientific community. The greater the number of researchers selected, the greater the amplitude and the domain boundary under consideration; the more restricted the number of researchers chosen as representative and appropriate, the less extensive the domain. From the perspective of the first axis of Tennis (2003), the selection of authors involves setting parameters on the extent of the domain, i.e., its total scope and amplitude. Thus, from the point of view of Tennis’s (2003) approach to Domain Analysis, the selection of authors for Author Cocitation Analysis is associated with the designations and boundaries of the domain, as well as to their goals (Tennis, 2003). Still, the selection of authors through the most cited authors in the literature, reflects the core elements of a domain and constitute the most specific foundation of a domain, aligning to the Degrees of Specialization characterized by Tennis (2003). It is concluded that the Author Cocitation Analysis (ACA) is a relevant procedure to the analysis of the underlying structure of a scientific knowledge domain, which meets the theories and concepts of Domain Analysis researchers, in that it allows characterizing the science, identifying, analyzing and assessing the conditions under which scientific knowledge is constructed and socialized.Universidade Estadual Paulista Júlio de Mesquita Filho, Departamento de Psicologia da Educação, Faculdade de Filosofia e Ciências - Campus de Marília, Marilia, Av. Hygino Muzzi Filho, 737, Campus Universitário, CEP 17525900, SP, BrasilUniversidade Estadual Paulista Júlio de Mesquita Filho, Departamento de Psicologia da Educação, Faculdade de Filosofia e Ciências - Campus de Marília, Marilia, Av. Hygino Muzzi Filho, 737, Campus Universitário, CEP 17525900, SP, BrasilUniversidade Estadual Paulista Júlio de Mesquita Filho, Departamento de Ciênciada Informação, Faculdade de Filosofia e Ciências - Campus de Marília, Marilia, Av. Hygino Muzzi Filho, 737, Campus Universitário, CEP 17525900, SP, Brasi
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